text: Applied Sciences http://www.mdpi.com/journal/applsci Latest open access articles published in Appl. Sci. at http://www.mdpi.com/journal/applsci http://www.mdpi.com/2076-3417/6/8/206 The development of engineered systems for energy dissipation (or absorption) during impacts or vibrations is an increasing need in our society, mainly for human protection applications, but also for ensuring the right performance of different sort of devices, facilities or installations. In the last decade, new energy dissipating composites based on the use of certain complex fluids have flourished, due to their non-linear relationship between stress and strain rate depending on the flow/field configuration. This manuscript intends to review the different approaches reported in the literature, analyses the fundamental physics behind them and assess their pros and cons from the perspective of their practical applications. Applied Sciences 2016-07-25 6 8 Review 10.3390/app6080206 206 2076-3417 2016-07-25 doi: 10.3390/app6080206 Francisco Galindo-Rosales http://www.mdpi.com/2076-3417/6/8/208 In this paper, an optical angle sensor with a birefringent transducer for measuring angular displacement based on a heterodyne interferometry is proposed. The achievable repeatability and linearity provide sufficient evidence for the practical use. As a result, a resolution of 5.8 × 10−6 with a dynamic range of 5° has been achieved by utilizing a KTP (potassium titanyl phosphate) plate immersed in a high refractive index oil with refractive index of 1.7. Applied Sciences 2016-07-25 6 8 Article 10.3390/app6080208 208 2076-3417 2016-07-25 doi: 10.3390/app6080208 Ruey-Ching Twu Ching-Shing Wang http://www.mdpi.com/2076-3417/6/7/205 We proposed heterodyne angle deviation interferometry (HADI) for angle deviation measurements. The phase shift of an angular sensor (which can be a metal film or a surface plasmon resonance (SPR) prism) is proportional to the deviation angle of the test beam. The method has been demonstrated in bubble and speaker's vibration measurements in this paper. In the speaker's vibration measurement, the voltage from the phase channel of a lock-in amplifier includes the vibration level and frequency. In bubble measurement, we can count the number of bubbles passing through the cross section of the laser beam and measure the bubble size from the phase pulse signal. Applied Sciences 2016-07-19 6 7 Article 10.3390/app6070205 205 2076-3417 2016-07-19 doi: 10.3390/app6070205 Ming-Hung Chiu Jia-Ze Shen Jian-Ming Huang http://www.mdpi.com/2076-3417/6/7/204 A systematic method to identify key factors that control the synthesis of Physical Vapor Deposition (PVD)-based graphene on copper is necessary for engineering graphene growth. The statistical design-of-experiments method is employed and demonstrated in this work in order to fulfill the necessity. Full-factorial design-of-experiments are performed to examine the significance of the main effects and the extent of the interactions of the controlling factors, which are responsible for the number of layers and the quality of the grown graphene. We found that a thinner amorphous carbon layer and a higher annealing temperature are suitable for the growth of mono-layer/few-layer graphene with low defects, while the effect of annealing time has a trade-off and needs to be optimized further. On the other hand, the same treatment, but with larger annealing times will result in multi-layer graphene and low defects. The results obtained from the analysis of the design-of-experiments are verified experimentally with Raman characterization. Applied Sciences 2016-07-14 6 7 Article 10.3390/app6070204 204 2076-3417 2016-07-14 doi: 10.3390/app6070204 Udit Narula Cher Tan http://www.mdpi.com/2076-3417/6/7/202 This paper describes the fabrication of a series of micro ball-ended stylus tips by applying micro-EDM (Electrical Discharge Machining) and OPED (One Pulse Electrical Discharge) processes, followed by a manual assembly process of a static tri-switches tactile structure on a micro-CMM (Coordinate Measuring Machine). This paper further proves that the essential performance of the proposed system meets an acceptable benchmark among peer micro-CMM systems with a low cost. The system also adjusts for ambient temperature and humidity as the ordinary lab environmental conditions. For demonstration, several experiments used a randomly selected glass stylus with the diameters of stem and sphere of 0.07 mm and 0.12 mm, respectively. By leveraging research guidelines and common practice, this paper further investigates the probing relationship between measurement accuracy and its associated critical characteristics, namely triggering scenarios and geometric feature probing validation. The experimental results show that repeated detections in the uncertainty, in vertical and horizontal directions of the same point, achieved as small as 0.11 μm and 0.29 μm, respectively. This customized tri-switches tactile probing structure was also capable of measuring geometric features of micro-components, such as the inner profile and depth of a micro-hole. Finally, extensions of the proposed approach to pursue higher accuracy measurement are discussed. Applied Sciences 2016-07-13 6 7 Article 10.3390/app6070202 202 2076-3417 2016-07-13 doi: 10.3390/app6070202 Yin Sun Kuo-Yu Tseng Dong-Yea Sheu http://www.mdpi.com/2076-3417/6/7/203 Focusing on incremental bulk metal forming processes, the indentation process is gaining interest as a fundamental part of these kinds of processes. This paper presents the analysis of the pressure obtained in indentation under the influence of different punch geometries. To this end, an innovative Upper Bound Theorem (UBT) based solution is introduced. This new solution can be easily applied to estimate the necessary force that guarantees plastic deformation by an indentation process. In this work, we propose an accurate analytical approach to analyse indentation under different punches. The new Modular Upper Bound (MUB) method presents a simpler and faster application. Additionally, its complexity is not considerably increased by the addition of more Triangular Rigid Zones. In addition, a two-dimensional indentation model is designed and implemented using the Finite Element Method (FEM). The comparison of the two methods applied to the indentation process analysed—the new Modular Upper Bound technique and the Finite Element Method—reveal close similarities, the new Modular Upper Bound being more computationally efficient. Applied Sciences 2016-07-12 6 7 Article 10.3390/app6070203 203 2076-3417 2016-07-12 doi: 10.3390/app6070203 Carolina Bermudo Lorenzo Sevilla Francisco Martín Francisco Trujillo http://www.mdpi.com/2076-3417/6/7/201 With the development of intelligent machine tools, monitoring the vibration by the accelerometer is an important issue. Accelerometers used for measuring vibration signals during milling processes require the characteristics of high sensitivity, high resolution, and high bandwidth. A commonly used accelerometer is the lead zirconate titanate (PZT) type; however, integrating it into intelligent modules is excessively expensive and difficult. Therefore, the micro electro mechanical systems (MEMS) accelerometer is an alternative with the advantages of lower price and superior integration. In the present study, we integrated two MEMS accelerometer chips into a low-pass filter and housing to develop a low-cost dual-axis accelerometer with a bandwidth of 5 kHz and a full scale range of ±50 g for measuring machine tool vibration. In addition, a platform for measuring the linearity, cross-axis sensitivity and frequency response of the MEMS accelerometer by using the back-to-back calibration method was also developed. Finally, cutting experiments with steady and chatter cutting were performed to verify the results of comparing the MEMS accelerometer with the PZT accelerometer in the time and frequency domains. The results demonstrated that the dual-axis MEMS accelerometer is suitable for monitoring the vibration of machine tools at low cost. Applied Sciences 2016-07-12 6 7 Article 10.3390/app6070201 201 2076-3417 2016-07-12 doi: 10.3390/app6070201 Chih-Yung Huang Jian-Hao Chen http://www.mdpi.com/2076-3417/6/7/194 In cold climates, electrical power demand for space conditioning becomes a critical issue for utility companies during certain periods of the day. Shifting a portion or all of it to off-peak periods can help reduce peak demand and reduce stress on the electrical grid. Sensible thermal energy storage (TES) systems, and particularly electrically heated floors (EHF), can store thermal energy in buildings during the off-peak periods and release it during the peak periods while maintaining occupants' thermal comfort. However, choosing the type of storage system and/or its configuration may be difficult. In this paper, the performance of an EHF for load management is studied. First, a methodology is developed to integrate EHF in TRNSYS program in order to investigate the impact of floor assembly on the EHF performance. Then, the thermal comfort (TC) of the night-running EHF is studied. Finally, indicators are defined, allowing the comparison of different EHF. Results show that an EHF is able to shift 84% of building loads to the night while maintaining acceptable TC in cold climate. Moreover, this system is able to provide savings for the customer and supplier if there is a significant difference between off-peak and peak period electricity prices. Applied Sciences 2016-07-11 6 7 Article 10.3390/app6070194 194 2076-3417 2016-07-11 doi: 10.3390/app6070194 Hélène Thieblemont Fariborz Haghighat Alain Moreau http://www.mdpi.com/2076-3417/6/7/200 In this work, we developed a Selective Dynamic Sampling Approach (SDSA) to deal with the class imbalance problem. It is based on the idea of using only the most appropriate samples during the neural network training stage. The "average samples"are the best to train the neural network, they are neither hard, nor easy to learn, and they could improve the classifier performance. The experimental results show that the proposed method is a successful method to deal with the two-class imbalance problem. It is very competitive with respect to well-known over-sampling approaches and dynamic sampling approaches, even often outperforming the under-sampling and standard back-propagation methods. SDSA is a very simple method for automatically selecting the most appropriate samples (average samples) during the training of the back-propagation, and it is very efficient. In the training stage, SDSA uses significantly fewer samples than the popular over-sampling approaches and even than the standard back-propagation trained with the original dataset. Applied Sciences 2016-07-11 6 7 Article 10.3390/app6070200 200 2076-3417 2016-07-11 doi: 10.3390/app6070200 Roberto Alejo Juan Monroy-de-Jesús Juan Pacheco-Sánchez Erika López-González Juan Antonio-Velázquez http://www.mdpi.com/2076-3417/6/7/198 A new series of benzylaminochalcone derivatives with different substituents on ring B were synthesized and evaluated as inhibitors of acetylcholinesterase. The study is aimed at identification of novel benzylaminochalcones capable of blocking acetylcholinesterase activity for further development of an approach to Alzheimer's disease treatment. These compounds were produced in moderate to good yields via Claisen-Schmidt condensation and subjected to an in vitro acetylcholinesterase inhibition assay, using Ellman's method. The in silico docking procedure was also employed to identify molecular interactions between the chalcone compounds and the enzyme. Compounds with ring B bearing pyridin-4-yl, 4-nitrophenyl, 4-chlorophenyl and 3,4-dimethoxyphenyl moieties were discovered to exhibit significant inhibitory activities against acetylcholinesterase, with IC50 values ranging from 23 to 39 µM. The molecular modeling studies are consistent with the hypothesis that benzylaminochalcones could exert their effects as dual-binding-site acetylcholinesterase inhibitors, which might simultaneously enhance cholinergic neurotransmission and inhibit β-amyloid aggregation through binding to both catalytic and peripheral sites of the enzyme. These derivatives could be further developed to provide novel leads for the discovery of new anti-Alzheimer drugs in the future. Applied Sciences 2016-07-07 6 7 Article 10.3390/app6070198 198 2076-3417 2016-07-07 doi: 10.3390/app6070198 Thanh-Dao Tran Thi-Cam-Vi Nguyen Ngoc-Son Nguyen Dai-Minh Nguyen Thi-Thu-Ha Nguyen Minh-Tri Le Khac-Minh Thai http://www.mdpi.com/2076-3417/6/7/199 As the sound signal of a machine contains abundant information and is easy to measure, acoustic-based monitoring or diagnosis systems exhibit obvious superiority, especially in some extreme conditions. However, the sound directly collected from industrial field is always polluted. In order to eliminate noise components from machinery sound, a wavelet threshold denoising method optimized by an improved fruit fly optimization algorithm (WTD-IFOA) is proposed in this paper. The sound is firstly decomposed by wavelet transform (WT) to obtain coefficients of each level. As the wavelet threshold functions proposed by Donoho were discontinuous, many modified functions with continuous first and second order derivative were presented to realize adaptively denoising. However, the function-based denoising process is time-consuming and it is difficult to find optimal thresholds. To overcome these problems, fruit fly optimization algorithm (FOA) was introduced to the process. Moreover, to avoid falling into local extremes, an improved fly distance range obeying normal distribution was proposed on the basis of original FOA. Then, sound signal of a motor was recorded in a soundproof laboratory, and Gauss white noise was added into the signal. The simulation results illustrated the effectiveness and superiority of the proposed approach by a comprehensive comparison among five typical methods. Finally, an industrial application on a shearer in coal mining working face was performed to demonstrate the practical effect. Applied Sciences 2016-07-06 6 7 Article 10.3390/app6070199 199 2076-3417 2016-07-06 doi: 10.3390/app6070199 Jing Xu Zhongbin Wang Chao Tan Lei Si Lin Zhang Xinhua Liu http://www.mdpi.com/2076-3417/6/7/197 Solution-processed CdTe nanocrystals (NCs) photovoltaic devices have many advantages, both in commercial manufacture and daily operation, due to the low-cost fabrication process, which becomes a competitive candidate for next-generation solar cells. All solution-processed CdTe NCs solar cells were first reported in 2005. In recent years, they have increased over four-fold in power conversion efficiency. The latest devices achieve AM 1.5 G power conversion efficiency up to 12.0%, values comparable to those of commercial thin film CdTe/CdS solar cells fabricated by the close-space sublimation (CSS) method. Here we review the progress and prospects in this field, focusing on new insights into CdTe NCs synthesized, device fabrication, NC solar cell operation, and how these findings give guidance on optimizing solar cell performance. Applied Sciences 2016-07-04 6 7 Review 10.3390/app6070197 197 2076-3417 2016-07-04 doi: 10.3390/app6070197 Hao Xue Rongfang Wu Ya Xie Qiongxuan Tan Donghuan Qin Hongbin Wu Wenbo Huang http://www.mdpi.com/2076-3417/6/7/196 For satisfactory traffic management of an intelligent transport system, it is vital that traffic microwave radar detectors (TMRDs) can provide real-time traffic information with high accuracy. In this study, we develop several information-aided smart schemes for traffic detection improvements of TMRDs in multiple-lane environments. Specifically, we select appropriate thresholds not only for removing noise from fast Fourier transforms (FFTs) of regional lane contexts but also for reducing FFT side lobes within each lane. The resulting FFTs of reflected vehicle signals and those of clutter are distinguishable. We exploit FFT and lane-/or time stamp-related information for developing smart schemes, which mitigate adverse effects of lane-crossing FFT side lobes of a vehicle signal. As such, the proposed schemes can enhance the detection accuracy of both lane vehicle flow and directional traffic volume. On-site experimental results demonstrate the advantages and feasibility of the proposed methods, and suggest the best smart scheme. Applied Sciences 2016-07-04 6 7 Article 10.3390/app6070196 196 2076-3417 2016-07-04 doi: 10.3390/app6070196 Tan-Jan Ho Meng-Ju Chung http://www.mdpi.com/2076-3417/6/7/181 Portable articulated coordinate measuring machine (PACMM) is a kind of high accuracy coordinate measurement instrument and it has been widely applied in manufacturing and assembly. A number of key problems should be taken into consideration to achieve the required accuracy, such as structural design, mathematical measurement model and calibration method. Although the classical kinematic model of PACMM is the Denavit-Hartenberg (D-H) model, the representation of D-H encounters the badly-conditioned problem when the consecutive joint axes are parallel or nearly parallel. In this paper, a new kinematic model of PACMM based on a generalized geometric error model which eliminates the inadequacies of D-H model has been proposed. Furthermore, the generalized geometric error parameters of PACMM are optimized by the Levenberg-Marquard (L-M) algorithm. The experimental result demonstrates that the measurement of standard deviation of PACMM based on the generalized geometric error model has been reduced from 0.0627 mm to 0.0452 mm with respect to the D-H model. Applied Sciences 2016-07-01 6 7 Article 10.3390/app6070181 181 2076-3417 2016-07-01 doi: 10.3390/app6070181 Hui-Ning Zhao Lian-Dong Yu Hua-Kun Jia Wei-Shi Li Jing-Qi Sun http://www.mdpi.com/2076-3417/6/7/195 Recently, high-frame-rate ultrasound has been extensively studied for measurement of tissue dynamics, such as pulsations of the carotid artery and heart. Motion estimators are very important for such measurements of tissue dynamics. In high-frame-rate ultrasound, the tissue displacement between frames becomes very small owing to the high temporal resolution. Under such conditions, the speckle tracking method requires high levels of interpolation to estimate such a small displacement. A phase-sensitive motion estimator is feasible because it does not suffer from the aliasing effect by such a small displacement and does not require interpolation to estimate a sub-sample displacement. In the present study, two phase-sensitive 2D motion estimators, namely, paired 1D motion estimators and 2D motion estimator with shifted cross spectra, were developed. Phase-sensitive motion estimators using frequency spectra of ultrasonic echoes have already been proposed in previous studies. However, such methods had not taken into account the ambiguity of the frequency of each component of the spectrum. We have proposed a method, which estimates the mean frequency of each component of the spectrum, and the proposed method was validated by a phantom experiment. The experimental results showed that the bias errors in the estimated motion velocities of the phantom were less than or equal to (11.5% in lateral, 2.0% in axial) by the proposed 1D paired motion estimators and (3.0%, 2.0%) by the proposed 2D motion estimators, both of which were significantly smaller than (14.0%, 3.0%) of the conventional phase-sensitive 2D motion estimator. Applied Sciences 2016-06-30 6 7 Article 10.3390/app6070195 195 2076-3417 2016-06-30 doi: 10.3390/app6070195 Hideyuki Hasegawa http://www.mdpi.com/2076-3417/6/7/193 Efforts to simulate heat transfer in a PCM (Phase Change Material) storage device are generally led by considerations of Biot number and material thickness, of 2D versus 1D representation, and of possible hysteresis effects arising from the characterisation of the PCM using differential scanning calorimetry (DSC). In this paper we present a numerical treatment of heat conduction in a paraffin-based storage brick, based on experimental data for a full scale, heat storage component studied under laboratory conditions. The PCM was modelled adopting equivalent thermophysical properties during the phase change. An equivalent heat capacity and thermal conductivity were provided for an appropriate description of energy release and storage in the process of solidification and melting. The geometry of the metal container induces 2D effects that are generally neglected in numerical modelling. The thickness of the plates (about 2 cm) is sufficiently large to require the modelling of conduction in the PCM, but can also induce convection that has been neglected in this study. Experimental results are presented and compared for both a 1D and 2D model of the PCM device. It was concluded that a 2D representation is essential for configurations; like the case study and geometry we had; with a large difference in thermal conductivity between PCM and metal casing. Two curves of equivalent heat capacity (measured via DSC) were introduced for heating and cooling phases. Comparisons to experimental results indicated significant errors in the models during melting and solidification of the PCM, which could be reduced by instead adopting the mean of the two heat capacity curves. The rate of temperature change during the experiments and for the DSC characterisation was analysed and found to explain well the observations. In particular, as novelty, two peaks of equivalent heat capacity have been observed with DSC when the rate is very low instead of only one peak using current rate: and that explains the real behaviour in the experiments. Applied Sciences 2016-06-30 6 7 Article 10.3390/app6070193 193 2076-3417 2016-06-30 doi: 10.3390/app6070193 Joseph Virgone Abdelkrim Trabelsi http://www.mdpi.com/2076-3417/6/7/192 In this paper, a flexible control strategy for a synthesis model dedicated to nonlinear friction phenomena is proposed. This model enables to synthesize different types of sound sources, such as creaky doors, singing glasses, squeaking wet plates or bowed strings. Based on the perceptual stance that a sound is perceived as the result of an action on an object we propose a genuine source/filter synthesis approach that enables to elude physical constraints induced by the coupling between the interacting objects. This approach makes it possible to independently control and freely combine the action and the object. Different implementations and applications related to computer animation, gesture learning for rehabilitation and expert gestures are presented at the end of this paper. Applied Sciences 2016-06-30 6 7 Article 10.3390/app6070192 192 2076-3417 2016-06-30 doi: 10.3390/app6070192 Etienne Thoret Mitsuko Aramaki Charles Gondre Sølvi Ystad Richard Kronland-Martinet http://www.mdpi.com/2076-3417/6/7/187 Single electron devices (SEDs) afford the opportunity to isolate and manipulate individual electrons. This ability imbues SEDs with potential applications in a wide array of areas from metrology (current and capacitance) to quantum information. Success in each application ultimately requires exceptional performance, uniformity, and stability from SEDs which is currently unavailable. In this review, we discuss a time instability of SEDs that occurs at low frequency ( ≪ 1 Hz) called charge offset drift. We review experimental work which shows that charge offset drift is large in metal-based SEDs and absent in Si-SiO2-based devices. We discuss the experimental results in the context of glassy relaxation as well as prospects of SED device applications. Applied Sciences 2016-06-29 6 7 Review 10.3390/app6070187 187 2076-3417 2016-06-29 doi: 10.3390/app6070187 M. Stewart Neil Zimmerman http://www.mdpi.com/2076-3417/6/7/188 Polymer flooding is now considered a technically- and commercially-proven method for enhanced oil recovery (EOR). The viscosity of the injected polymer solution is the key property for successful polymer flooding. Given that the viscosity of a polymer solution has a non-linear relationship with various influential parameters (molecular weight, degree of hydrolysis, polymer concentration, cation concentration of polymer solution, shear rate, temperature) and that measurement of viscosity based on these parameters is a time-consuming process, the range of solution samples and the measurement conditions need to be limited and precise. Viscosity estimation of the polymer solution is effective for these purposes. An artificial neural network (ANN) was applied to the viscosity estimation of FlopaamTM 3330S, FlopaamTM 3630S and AN-125 solutions, three commonly-used EOR polymers. The viscosities measured and estimated by ANN and the Carreau model using Lee's correlation, the only method for estimating the viscosity of an EOR polymer solution in unmeasured conditions, were compared. Estimation accuracy was evaluated by the average absolute relative deviation, which has been widely used for accuracy evaluation of the results of ANN models. In all conditions, the accuracy of the ANN model is higher than that of the Carreau model using Lee's correlation. Applied Sciences 2016-06-29 6 7 Article 10.3390/app6070188 188 2076-3417 2016-06-29 doi: 10.3390/app6070188 Pan-Sang Kang Jong-Se Lim Chun Huh http://www.mdpi.com/2076-3417/6/7/189 In this paper, we propose a fuzzy case-based reasoning system, using a case-based reasoning (CBR) system that learns from experience to solve problems. Different from a traditional case-based reasoning system that uses crisp cases, our system works with fuzzy ones. Specifically, we change a crisp case into a fuzzy one by fuzzifying each crisp case element (feature), according to the maximum degree principle. Thus, we add the "vague" concept into a case-based reasoning system. It is these somewhat vague inputs that make the outcomes of the prediction more meaningful and accurate, which illustrates that it is not necessarily helpful when we always create accurate predictive relations through crisp cases. Finally, we prove this and apply this model to practical weather forecasting, and experiments show that using fuzzy cases can make some prediction results more accurate than using crisp cases. Applied Sciences 2016-06-29 6 7 Article 10.3390/app6070189 189 2076-3417 2016-06-29 doi: 10.3390/app6070189 Jing Lu Dingling Bai Ning Zhang Tiantian Yu Xiakun Zhang http://www.mdpi.com/2076-3417/6/7/190 A method for analysing the effect of different hypotheses about the type of the input quantities distributions of a measurement model is presented here so that the developed algorithms can be simplified. As an example, a model of indirect measurements with optical coordinate measurement machine was employed to evaluate these different hypotheses. As a result of the different experiments, the assumption that the different variables of the model can be modelled as normal distributions is proved. Applied Sciences 2016-06-28 6 7 Article 10.3390/app6070190 190 2076-3417 2016-06-28 doi: 10.3390/app6070190 Jesús Caja Piera Maresca Emilio Gómez http://www.mdpi.com/2076-3417/6/7/191 The purpose of this research is to evaluate the fire-extinguishing performance of a compressed air foam system at different mixing ratios of pressurized air. In this system, compressed air is injected into an aqueous solution of foam and then discharged. The experimental device uses an exclusive fire-extinguishing technology with compressed air foam that is produced based on the Canada National Laboratory and UL (Underwriters Laboratories) 162 standards, with a 20-unit oil fire model (Class B) applied as the fire extinguisher. Compressed air is injected through the air mixture, and results with different air-to-aqueous solution foam ratios of 1:4, 1:7, and 1:10 are studied. In addition, comparison experiments between synthetic surfactant foam and a foam type which forms an aqueous film are carried out at an air-to-aqueous solution foam ratio of 1:4. From the experimental results, at identical discharging flows, it was found that the fire-extinguishing effect of the aqueous film-forming foam is greatest at an air-to-aqueous solution foam ratio of 1:7 and weakest at 1:10. Moreover, the fire-extinguishing effect of the aqueous film-forming foam in the comparison experiments between the aqueous film-forming foam and the synthetic surfactant foam is greatest. Applied Sciences 2016-06-28 6 7 Article 10.3390/app6070191 191 2076-3417 2016-06-28 doi: 10.3390/app6070191 Dong-Ho Rie Jang-Won Lee Seonwoong Kim http://www.mdpi.com/2076-3417/6/7/185 In this design study, we introduce a novel class of digital audio effects that extend the recently introduced modal processor approach to artificial reverberation and effects processing. These pitch and distortion processing effects mimic the design and sonics of a classic additive-synthesis-based electromechanical musical instrument, the Hammond tonewheel organ. As a reverb effect, the modal processor simulates a room response as the sum of resonant filter responses. This architecture provides precise, interactive control over the frequency, damping, and complex amplitude of each mode. Into this framework, we introduce two types of processing effects: pitch effects inspired by the Hammond organ's equal tempered "tonewheels", "drawbar" tone controls, vibrato/chorus circuit, and distortion effects inspired by the pseudo-sinusoidal shape of its tonewheels and electromagnetic pickup distortion. The result is an effects processor that imprints the Hammond organ's sonics onto any audio input. Applied Sciences 2016-06-28 6 7 Article 10.3390/app6070185 185 2076-3417 2016-06-28 doi: 10.3390/app6070185 Kurt Werner Jonathan Abel http://www.mdpi.com/2076-3417/6/7/186 Obesity, one of the major problems in modern society, adversely affects people's health and increases the risk of suffering degeneration in supportive tissues such as cartilage, which loses its ability to support and distribute loads. However, no specific research regarding obesity-associated alterations in the mechano-electrochemical cartilage environment has been developed. Such studies could help us to understand the first signs of cartilage degeneration when body weight increases and to establish preventive treatments to avoid cartilage deterioration. In this work, a previous mechano-electrochemical computational model has been further developed and employed to analyze and quantify the effects of obesity on the articular cartilage of the femoral hip. A comparison between the obtained results of the healthy and osteoarthritic cartilage has been made. It shows that behavioral patterns of cartilage, such as ion fluxes and cation distribution, have considerable similarities with those obtained for the early stages of osteoarthritis. Thus, an increment in the outgoing ion fluxes is produced, resulting in lower cation concentrations in all the cartilage layers. These results suggest that people with obesity, i.e. a body mass index greater than 30 kg/m2, should undergo preventive treatments for osteoarthritis to avoid homeostatic alterations and, subsequent, tissue deterioration. Applied Sciences 2016-06-24 6 7 Article 10.3390/app6070186 186 2076-3417 2016-06-24 doi: 10.3390/app6070186 Sara Manzano Manuel Doblaré Mohamed Hamdy Doweidar http://www.mdpi.com/2076-3417/6/6/182 Maize is one of the major food crops in China. Traditionally, field operations are done by manual labor, where the farmers are threatened by the harsh environment and pesticides. On the other hand, it is difficult for large machinery to maneuver in the field due to limited space, particularly in the middle and late growth stage of maize. Unmanned, compact agricultural machines, therefore, are ideal for such field work. This paper describes a method of monocular visual recognition to navigate small vehicles between narrow crop rows. Edge detection and noise elimination were used for image segmentation to extract the stalks in the image. The stalk coordinates define passable boundaries, and a simplified radial basis function (RBF)-based algorithm was adapted for path planning to improve the fault tolerance of stalk coordinate extraction. The average image processing time, including network latency, is 220 ms. The average time consumption for path planning is 30 ms. The fast processing ensures a top speed of 2 m/s for our prototype vehicle. When operating at the normal speed (0.7 m/s), the rate of collision with stalks is under 6.4%. Additional simulations and field tests further proved the feasibility and fault tolerance of our method. Applied Sciences 2016-06-21 6 6 Article 10.3390/app6060182 182 2076-3417 2016-06-21 doi: 10.3390/app6060182 Lu Liu Tao Mei Runxin Niu Jie Wang Yongbo Liu Sen Chu http://www.mdpi.com/2076-3417/6/6/183 Hyperspectral imaging (HSI) technology has been extensively studied in the classification of seed variety. A novel procedure for the classification of maize seed varieties based on HSI was proposed in this study. The optimal wavelengths for the classification of maize seed varieties were selected using the successive projections algorithm (SPA) to improve the acquiring and processing speed of HSI. Subsequently, spectral and imaging features were extracted from regions of interest of the hyperspectral images. Principle component analysis and multidimensional scaling were then introduced to transform/reduce the classification features for overcoming the risk of dimension disaster caused by the use of a large number of features. Finally, the integrating features were used to develop a least squares–support vector machines (LS–SVM) model. The LS–SVM model, using the integration of spectral and image features combined with feature transformation methods, achieved more than 90% of test accuracy, which was better than the 83.68% obtained by model using the original spectral and image features, and much higher than the 76.18% obtained by the model only using the spectral features. This procedure provides a possible way to apply the multispectral imaging system to classify seed varieties with high accuracy. Applied Sciences 2016-06-21 6 6 Article 10.3390/app6060183 183 2076-3417 2016-06-21 doi: 10.3390/app6060183 Min Huang Chujie He Qibing Zhu Jianwei Qin http://www.mdpi.com/2076-3417/6/6/179 Flip chip technology has been widely adopted in modern power light-emitting diode (LED) fabrications and its output efficiency is closely related to the submount material properties. Here, we present the electrical, optical and thermal properties of flip chip light-emitting diodes mounted on transparent sapphire and borosilicate glass which have shown a higher output luminous flux when compared to the traditional non-transparent mounted LEDs. Exhibiting both better thermal conductivity and good optical transparency, flip chip LEDs with a sapphire submount showed superior performance when compared to the non-transparent silicon submount ones, and also showed better optical performance than the flip chip LEDs mounted on transparent but poor-thermal-conducting glass substrates. The correspondent analysis was carried out using ANSYS 14 to compare the experimental thermal imaging with the simulation results. TracePro software was also used to check the output luminous flux dependency on different LED mounting designs. Applied Sciences 2016-06-20 6 6 Article 10.3390/app6060179 179 2076-3417 2016-06-20 doi: 10.3390/app6060179 Preetpal Singh Der-Hwa Yeh Cher-Ming Tan Chao-Sung Lai Chih-Teng Hou Ting-Yu Chao Liann-Be Chang http://www.mdpi.com/2076-3417/6/6/180 Saponins are pharmacologically active compounds that have been shown to ameliorate abnormal physiological processes and be aptly applied in folklore for the treatment of maladies occasioned by infectious agents. Consequently, saponins from Vitex doniana and Pentaclethra macrophylla were evaluated for antibacterial properties, as these herbs are used in folk medicine. Dried pulverized plant materials were defatted, and solvents with varying polarity were applied at varying ratios for the extraction of saponins. Phyto-chemistry was in accordance with standard methods, while an antibacterial assay was made through the agar well diffusion and micro broth dilution techniques. Phytochemical quantitation showed high concentrations of tannins, 231 ± 0.6 CE/g, and saponins, 58% from V. doniana. Similarly, P. macrophylla stem bark extract also showed high concentrations of tannins, 309 ± 2.42 CE/g, alkaloids, 71% ± 0.5%, and saponins, 87% ± 3.4%. The ethanol extracts of V. doniana inhibited the growth of Staphylococcus aureus (ATCC 11775) and a clinical strain with inhibition zone ranges of 15.5 ± 2.12 to 7.0 ± 0.0 (mm) against leaf extracts and 20.0 ± 1.41 to 7.0 ± 0.0 (mm) against stem bark extracts. Conversely, saponin extract from V. doniana showed a broad spectrum of activity, as it inhibited both Gram-negative and -positive test strains, E. coli clinical strain (20.0 ± 1.41 mm), P. aeruginosa clinical strain (18.5 ± 0.71 mm), E. coli ATCC 11775 (17.0 ± 0 mm), and S. aureus clinical strain (13.0 ± 1.41 mm). However, a broad spectrum was similarly achieved with P. macrophylla extracts, as all test bacteria genus was susceptible. Saponin fractions showed a high potency and broad spectrum antibacterial activity and thus a validation of the folklore applications and the potential for use as a drug or drug scaffold. Applied Sciences 2016-06-17 6 6 Article 10.3390/app6060180 180 2076-3417 2016-06-17 doi: 10.3390/app6060180 Nneoma Akaniro-Ejim Chibuike Ubani Nkoyo Nubila Alexander Nzei Uchechukwu Nwodo Anthony Okoh http://www.mdpi.com/2076-3417/6/6/176 Smart mobile phones are widely popularized and advanced mobile communication services are provided increasingly often, such that ubiquitous computing environments will soon be a reality. However, there are many security threats to mobile networks and their impact on security is more serious than that in wireline networks owing to the features of wireless transmissions and the ubiquity property. The secret information which mobile users carry may be stolen by malicious entities. To guarantee the quality of advanced services, security and privacy would be important issues when users roam within various mobile networks. In this manuscript, an anonymous authentication scheme will be proposed to protect the security of the network system and the privacy of users. Not only does the proposed scheme provide mutual authentication between each user and the system, but also each user's identity is kept secret against anyone else, including the system. Although the system anonymously authenticates the users, it can still generate correct bills to charge these anonymous users via a credit-based solution instead of debit-based ones. Furthermore, our protocols also achieve fair privacy which allows the judge to revoke the anonymity and trace the illegal users when they have misused the anonymity property, for example, if they have committed crimes. Finally, in this paper, we also carry out complete theoretical proofs on each claimed security property. Applied Sciences 2016-06-17 6 6 Article 10.3390/app6060176 176 2076-3417 2016-06-17 doi: 10.3390/app6060176 Chun-I Fan Vincent Huang http://www.mdpi.com/2076-3417/6/6/178 External bonding of carbon fiber sheets has become a popular technique for strengthening concrete structures all over the world. Epoxy adhesive, which is used to bond the carbon fiber sheets and concrete, deteriorates rapidly when being exposed to high temperatures. This paper presents a high-temperature-resistant modified magnesia-phosphate cement (MPC) with the compressive strength that does not decrease at the temperature of 600 °C. The bond properties of both the modified MPC and the epoxy adhesive between externally bonded carbon fiber sheets and concrete were evaluated by using a double-shear test method after exposure to elevating temperatures from 105 °C to 500 °C. The results showed that the bond strength of the modified MPC at room temperature (RT) is much higher than that of the epoxy resin. Full carbonation with almost 0 MPa was detected for the epoxy sample after the exposure to 300 °C, while only 40% reduction of bond strength was tested for the modified MPC sample. Although the modified MPC specimens failed through interlaminar slip of fiber strips instead of complete debonding, the MPC specimens performed higher bond strength than epoxy resin at ambient temperature, and retained much higher bond strength at elevated temperatures. It could be concluded that it is feasible to strengthen concrete structural members with externally bonded carbon fiber sheets using the modified MPC instead of epoxy adhesive. Furthermore, the use of the modified MPC as the binder between carbon fiber sheets and concrete can be less expensive and an ecologically friendly alternative. Applied Sciences 2016-06-17 6 6 Article 10.3390/app6060178 178 2076-3417 2016-06-17 doi: 10.3390/app6060178 Ailian Zhang Xiaojian Gao http://www.mdpi.com/2076-3417/6/6/177 In wildfire science, spotting refers to non-local creation of new fires, due to downwind ignition of brands launched from a primary fire. Spotting is often mentioned as being one of the most difficult problems for wildfire management, because of its unpredictable nature. Since spotting is a stochastic process, it makes sense to talk about a probability distribution for spotting, which we call the spotting distribution. Given a location ahead of the fire front, we would like to know how likely is it to observe a spot fire at that location in the next few minutes. The aim of this paper is to introduce a detailed procedure to find the spotting distribution. Most prior modelling has focused on the maximum spotting distance, or on physical subprocesses. We will use mathematical modelling, which is based on detailed physical processes, to derive a spotting distribution. We discuss the use and measurement of this spotting distribution in fire spread, fire management and fire breaching. The appendix of this paper contains a comprehensive review of the relevant underlying physical sub-processes of fire plumes, launching fire brands, wind transport, falling and terminal velocity, combustion during transport, and ignition upon landing. Applied Sciences 2016-06-17 6 6 Article 10.3390/app6060177 177 2076-3417 2016-06-17 doi: 10.3390/app6060177 Jonathan Martin Thomas Hillen http://www.mdpi.com/2076-3417/6/6/175 Society is more and more interested in developing mathematical models to assess and forecast the environmental and biological health conditions of our planet. However, most existing models cannot determine the long-range impacts of potential policies without considering the complex global factors and their cross effects in biological systems. In this paper, the Markov property and Neural Network Ensemble (NNE) are utilized to construct an estimated matrix that combines the interaction of the different local factors. With such an estimation matrix, we could obtain estimated variables that could reflect the global influence. The ensemble weights are trained by multiple population algorithms. Our prediction could fit the real trend of the two predicted measures, namely Morbidity Rate and Gross Domestic Product (GDP). It could be an effective method of reflecting the relationship between input factors and predicted measures of the health of ecosystems. The method can perform a sensitivity analysis, which could help determine the critical factors that could be adjusted to move the ecosystem in a sustainable direction. Applied Sciences 2016-06-15 6 6 Article 10.3390/app6060175 175 2076-3417 2016-06-15 doi: 10.3390/app6060175 Rong Shan Zeng-Shun Zhao Pan-Fei Chen Wei-Jian Liu Shu-Yi Xiao Yu-Han Hou Mao-Yong Cao Fa-Liang Chang Zhigang Wang http://www.mdpi.com/2076-3417/6/6/174 Gaze estimation methods play an important role in a gaze tracking system. A novel 2D gaze estimation method based on the pupil-glint vector is proposed in this paper. First, the circular ring rays location (CRRL) method and Gaussian fitting are utilized for pupil and glint detection, respectively. Then the pupil-glint vector is calculated through subtraction of pupil and glint center fitting. Second, a mapping function is established according to the corresponding relationship between pupil-glint vectors and actual gaze calibration points. In order to solve the mapping function, an improved artificial neural network (DLSR-ANN) based on direct least squares regression is proposed. When the mapping function is determined, gaze estimation can be actualized through calculating gaze point coordinates. Finally, error compensation is implemented to further enhance accuracy of gaze estimation. The proposed method can achieve a corresponding accuracy of 1.29°, 0.89°, 0.52°, and 0.39° when a model with four, six, nine, or 16 calibration markers is utilized for calibration, respectively. Considering error compensation, gaze estimation accuracy can reach 0.36°. The experimental results show that gaze estimation accuracy of the proposed method in this paper is better than that of linear regression (direct least squares regression) and nonlinear regression (generic artificial neural network). The proposed method contributes to enhancing the total accuracy of a gaze tracking system. Applied Sciences 2016-06-14 6 6 Article 10.3390/app6060174 174 2076-3417 2016-06-14 doi: 10.3390/app6060174 Jianzhong Wang Guangyue Zhang Jiadong Shi http://www.mdpi.com/2076-3417/6/6/173 The paper describes the strategy adopted to assess the structural condition of the tallest historic tower in Mantua (Italy) after the Italian seismic sequence of May–June 2012 and exemplifies the application of health monitoring using (automated) operational modal analysis. The post-earthquake survey (including extensive visual inspection, historic and documentary research, non-destructive (ND) material testing, and ambient vibration tests) highlighted the poor state of preservation of the upper part of the tower; subsequently, a dynamic monitoring system (consisting of a few accelerometers and one temperature sensor) was installed in the building to address the preservation of the historic structure, and automated modal identification was continuously performed. Despite the low levels of vibration that existed in operational conditions, the analysis of data collected over a period of about 15 months allowed to assess and model the effects of changing temperature on modal frequencies and to detect the occurrence of abnormal behavior and damage under the changing environment. The monitoring results demonstrate the potential key role of vibration-based structural health monitoring, implemented through low-cost hardware solutions and appropriate software tools, in the preventive conservation and the condition-based maintenance of historic towers. Applied Sciences 2016-06-08 6 6 Article 10.3390/app6060173 173 2076-3417 2016-06-08 doi: 10.3390/app6060173 Antonella Saisi Marco Guidobaldi Carmelo Gentile http://www.mdpi.com/2076-3417/6/6/170 Sago biomass is an agro-industrial waste produced in large quantities, mainly in the Asia-Pacific region and in particular South-East Asia. This work focuses on using sago biomass to obtain cellulose as the raw material, through chemical processing using acid hydrolysis, alkaline extraction, chlorination and bleaching, finally converting the material to pharmaceutical grade carboxymethyl sago cellulose (CMSC) by carboxymethylation. The cellulose was evaluated using Thermogravimetric Analysis (TGA), Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and Field Emission Scanning Electronic Microscopy (FESEM). The extracted cellulose was analyzed for cellulose composition, and subsequently modified to CMSC with a degree of substitution (DS) 0.6 by typical carboxymethylation reactions. X-ray diffraction analysis indicated that the crystallinity of the sago cellulose was reduced after carboxymethylation. FTIR and NMR studies indicate that the hydroxyl groups of the cellulose fibers were etherified through carboxymethylation to produce CMSC. Further characterization of the cellulose and CMSC were performed using FESEM and DSC. The purity of CMSC was analyzed according to the American Society for Testing and Materials (ASTM) International standards. In this case, acid and alkaline treatments coupled with high-pressure defibrillation were found to be effective in depolymerization and defibrillation of the cellulose fibers. The synthesized CMSC also shows no toxicity in the cell line studies and could be exploited as a pharmaceutical excipient. Applied Sciences 2016-06-08 6 6 Article 10.3390/app6060170 170 2076-3417 2016-06-08 doi: 10.3390/app6060170 Anand Veeramachineni Thenapakiam Sathasivam Saravanan Muniyandy Pushpamalar Janarthanan Steven Langford Lim Yan http://www.mdpi.com/2076-3417/6/6/172 Hard machining is an efficient solution that can be used to replace the grinding operation in the mold and die manufacturing industry. In this study, an attempt is made to analyze the effect of process parameters on workpiece surface roughness (Ra) in the hard milling of JIS (Japanese Industrial Standard) SKD61 steel, based on a combination of the Taguchi method and response surface methodology (RSM). The cutting parameters are selected based on the structural dynamic analysis of the machine tool. A set of experiments is designed according to the Taguchi technique. The average Ra is measured by a Mitutoyo Surftest SJ-400, and then analysis of variance (ANOVA) is performed to determine the influences of cutting parameters on the given Ra. Quadratic mathematical modeling is introduced for prediction of the Ra during the hard milling process. The predicted values are in reasonable agreement with the observation of experiments. In an effort to obtain the minimizing Ra, a single objective optimization is employed based on the desirability function. The result shows that the percentage error between measured and predicted values of Ra is 3.2%, which is found to be insignificant. Eventually, the milled surface roughness under the optimized machining conditions is 0.122 µm. This finding shows that grinding may be replaced by finish hard milling in the mold and die manufacturing field. Applied Sciences 2016-06-08 6 6 Article 10.3390/app6060172 172 2076-3417 2016-06-08 doi: 10.3390/app6060172 Huu-That Nguyen Quang-Cherng Hsu http://www.mdpi.com/2076-3417/6/6/171 In order to accurately evaluate the health condition of a shearer, a hybrid prediction method was proposed based on the integration of a fuzzy neural network (FNN) and improved particle swarm optimization (IPSO). The parameters of FNN were optimized by the use of PSO, which was coupled with a premature judgment and mutation mechanism to increase the convergence speed and enhance the generalization ability. The key technologies are elaborated and the flowchart of the proposed approach was designed. Furthermore, an experiment example was carried out and the comparison results indicated that the proposed approach was feasible and outperforms others. Finally, a field application example in coal mining face was demonstrated to specify the effect of the proposed system. Applied Sciences 2016-06-07 6 6 Article 10.3390/app6060171 171 2076-3417 2016-06-07 doi: 10.3390/app6060171 Lei Si Zhongbin Wang Ze Liu Xinhua Liu Chao Tan Rongxin Xu http://www.mdpi.com/2076-3417/6/6/169 (Aim) Classification of brain images as pathological or healthy case is a key pre-clinical step for potential patients. Manual classification is irreproducible and unreliable. In this study, we aim to develop an automatic classification system of brain images in magnetic resonance imaging (MRI). (Method) Three datasets were downloaded from the Internet. Those images are of T2-weighted along axial plane with size of 256 × 256. We utilized an s-level decomposition on the basis of dual-tree complex wavelet transform (DTCWT), in order to obtain 12s "variance and entropy (VE)" features from each subband. Afterwards, we used support vector machine (SVM) and its two variants: the generalized eigenvalue proximal SVM (GEPSVM) and the twin SVM (TSVM), as the classifiers. In all, we proposed three novel approaches: DTCWT + VE + SVM, DTCWT + VE + GEPSVM, and DTCWT + VE + TSVM. (Results) The results showed that our "DTCWT + VE + TSVM" obtained an average accuracy of 99.57%, which was not only better than the two other proposed methods, but also superior to 12 state-of-the-art approaches. In addition, parameter estimation showed the classification accuracy achieved the largest when the decomposition level s was assigned with a value of 1. Further, we used 100 slices from real subjects, and we found our proposed method was superior to human reports from neuroradiologists. (Conclusions) This proposed system is effective and feasible. Applied Sciences 2016-06-03 6 6 Article 10.3390/app6060169 169 2076-3417 2016-06-03 doi: 10.3390/app6060169 Shuihua Wang Siyuan Lu Zhengchao Dong Jiquan Yang Ming Yang Yudong Zhang http://www.mdpi.com/2076-3417/6/6/167 Interference fit is an important contact mode used for torque transmission existing widely in engineering design. To prevent trackslip, a certain magnitude of interference has to be ensured; meanwhile, the interference needs to be controlled to avoid failure of the mechanical components caused by high assembly stress. The finite element method (FEM) can be used to analyze the stress, while the computational cost of FEM involving nonlinear contact algorithm is relatively high, and likely to come across low precision and convergence problems. Therefore, a rapid and accurate analytical method for estimation is of vital need, especially for the initial design stage when the parameters vary in a large range. In this study, an analytical method to calculate the contact pressure and stress between multi-layer thick-walled cylinders (MLTWC) with multi-contact pairs and temperature-raising effect is proposed, and evaluated by FEM. The analytical solution of the interference for tri-layer thick-walled cylinders is applied to the design of engine crankshaft bearing. The results indicate that the analytical method presented in this study can reduce complexity of MLTWC problems and improve the computational efficiency. It is well suited to be used for the calculation model of parameter optimization in early design. Applied Sciences 2016-06-02 6 6 Article 10.3390/app6060167 167 2076-3417 2016-06-02 doi: 10.3390/app6060167 Jun Qiu Ming Zhou http://www.mdpi.com/2076-3417/6/6/168 To understand the effects of effective microorganisms (EMs) containing multiple strains on microbes and nutrients in kiwifruit planting soil, EMs prepared with four different strains were added to kiwifruit planting soil monthly from April to August. The counts of bacteria, fungi, actinomycetes, and total microbes were determined. The pH, total nitrogen (TN), alkali-hydrolyzable nitrogen (A-N), organic matter (OM), available potassium (A-K), and available phosphorus (A-P) of the soil were measured. Results indicated that the counts of bacteria, fungi, actinomycetes, and total microbes reached 60.33 × 105, 4.00 × 105, 0.92 × 105, and 65.25 × 105 CFU/g, respectively, in August, all of which were higher than those of the control group (CK). The bacterial count of the experimental group (EG) was higher than that of the CK in August. The pH-values of the EG were always lower than those of the CK. In August, the TN content of the EG was 1.52 g/kg, which was higher than that of the CK (1.35 g/kg). A significant negative association between the actinomycetes count and TN (p < 0.05) was found. For A-N and OM, the content of the EG (A-N, 125.18 mg/kg; OM, 49.84 mg/kg) was roughly the same as that of the CK (A-N, 112.51 mg/kg; OM, 53.11 mg/kg) in August. However, the A-K and A-P contents of the EG (A-K, 145.25 mg/kg; A-P, 111.25 mg/kg) were lower than those of the CK (A-K, 182.52 mg/kg; A-P, 202.19 mg/kg) in August. Results show that application of EMs in kiwifruit planting soil can increase the counts of soil microbes and might promote the absorption of major nutrients for kiwifruit tree. Applied Sciences 2016-06-02 6 6 Article 10.3390/app6060168 168 2076-3417 2016-06-02 doi: 10.3390/app6060168 Liangqian Fan Xi Zhou Yongsheng Li Lin Ji Guoyan Wu Bei Li Lin Cheng Mei Long Wenwen Deng Likou Zou http://www.mdpi.com/2076-3417/6/6/164 In this study, an artificial neural network (ANN) model is developed to predict the stability number of breakwater armor stones based on the experimental data reported by Van der Meer in 1988. The harmony search (HS) algorithm is used to determine the near-global optimal initial weights in the training of the model. The stratified sampling is used to sample the training data. A total of 25 HS-ANN hybrid models are tested with different combinations of HS algorithm parameters. The HS-ANN models are compared with the conventional ANN model, which uses a Monte Carlo simulation to determine the initial weights. Each model is run 50 times and the statistical analyses are conducted for the model results. The present models using stratified sampling are shown to be more accurate than those of previous studies. The statistical analyses for the model results show that the HS-ANN model with proper values of HS algorithm parameters can give much better and more stable prediction than the conventional ANN model. Applied Sciences 2016-05-31 6 6 Article 10.3390/app6060164 164 2076-3417 2016-05-31 doi: 10.3390/app6060164 Anzy Lee Zong Geem Kyung-Duck Suh http://www.mdpi.com/2076-3417/6/6/166 Lithium-ion batteries are the primary power source in electric vehicles, and the prognosis of their remaining useful life is vital for ensuring the safety, stability, and long lifetime of electric vehicles. Accurately establishing a mechanism model of a vehicle lithium-ion battery involves a complex electrochemical process. Remaining useful life (RUL) prognostics based on data-driven methods has become a focus of research. Current research on data-driven methodologies is summarized in this paper. By analyzing the problems of vehicle lithium-ion batteries in practical applications, the problems that need to be solved in the future are identified. Applied Sciences 2016-05-27 6 6 Review 10.3390/app6060166 166 2076-3417 2016-05-27 doi: 10.3390/app6060166 Lifeng Wu Xiaohui Fu Yong Guan http://www.mdpi.com/2076-3417/6/6/161 Post-fermented Pu-erh tea (PFPT) has several health benefits, however, little is known about the bioactive compounds. In this study, a PFPT compound was isolated by column chromatography and identified as Teadenol A by spectroscopic data analyses, including mass spectrometry and 1D and 2D NMR spectroscopy. Teadenol A in tea leaves was biotransformed by Aspergillus niger and A. tamari at 28 °C for 14 d at concentrations ranging from 9.85 ± 1.17 to 12.93 ± 0.38 mg/g. Additionally, the compound was detected in 22 commercial PFPTs at concentrations ranging from 0.17 ± 0.1 to 8.15 ± 0.1 mg/g. Teadenol A promoted the secretion of adiponectin and inhibited the expression of protein tyrosine phosphatase-1B. Antioxidant assays (e.g., 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, total antioxidant capacity (T-AOC), hydrogen donating ability, and superoxide anion radical scavenging capacity) revealed that Teadenol A has antioxidant properties. Therefore, Teadenol A is an important bio-active component of PFPT. Applied Sciences 2016-05-26 6 6 Article 10.3390/app6060161 161 2076-3417 2016-05-26 doi: 10.3390/app6060161 Xiao-qin Su Gao-ju Zhang Yan Ma Mao Chen Sheng-hu Chen Shuang-mei Duan Jin-qiong Wan Fumio Hashimoto Hai-peng Lv Jia-hua Li Zhi Lin Ming Zhao http://www.mdpi.com/2076-3417/6/6/165 The electric vehicle market is rapidly growing due to its environmental friendliness and governmental support. As electric vehicles are powered by electricity, the interoperability between the vehicles and the chargers made by multiple vendors is crucial for the success of the technology. Relevant standards are being published, but the methods for conformance testing need to be developed. In this paper, we present our conformance test system for the electric vehicle charger in accordance with the standards ISO/IEC 15118, IEC 61851 and IEC 61850-90-8. Our test system leverages the TTCN-3 framework for its flexibility and productivity. We evaluate the test system by lab tests with two reference chargers that we built. We also present the test results in two international testival events for the ISO/IEC 15118 interoperability. We confirmed that our test system is robust, efficient and practical. Applied Sciences 2016-05-26 6 6 Article 10.3390/app6060165 165 2076-3417 2016-05-26 doi: 10.3390/app6060165 Minho Shin Hwimin Kim Hyoseop Kim Hyuksoo Jang http://www.mdpi.com/2076-3417/6/6/162 This paper presents and discusses various metrics proposed for evaluation of polyphonic sound event detection systems used in realistic situations where there are typically multiple sound sources active simultaneously. The system output in this case contains overlapping events, marked as multiple sounds detected as being active at the same time. The polyphonic system output requires a suitable procedure for evaluation against a reference. Metrics from neighboring fields such as speech recognition and speaker diarization can be used, but they need to be partially redefined to deal with the overlapping events. We present a review of the most common metrics in the field and the way they are adapted and interpreted in the polyphonic case. We discuss segment-based and event-based definitions of each metric and explain the consequences of instance-based and class-based averaging using a case study. In parallel, we provide a toolbox containing implementations of presented metrics. Applied Sciences 2016-05-25 6 6 Article 10.3390/app6060162 162 2076-3417 2016-05-25 doi: 10.3390/app6060162 Annamaria Mesaros Toni Heittola Tuomas Virtanen http://www.mdpi.com/2076-3417/6/6/163 The elastic property of the film-substrate interface of thin-film systems is characterized with an opto-acoustic method. The thin-film specimens are oscillated with an acoustic transducer at audible frequencies, and the resultant harmonic response of the film surface is analyzed with optical interferometry. Polystyrene, Ti, Ti-Au and Ti-Pt films coated on the same silicon substrate are tested. For each film material, a pair of specimens is prepared; one is coated on a silicon substrate after the surface is treated with plasma bombardment, and the other is coated on an identical silicon substrate without a treatment. Experiments indicate that both the surface-treated and untreated specimens of all film materials have resonance in the audible frequency range tested. The elastic constant of the interface corresponding to the observed resonance is found to be orders of magnitude lower than that of the film or substrate material. Observations of these resonance-like behaviors and the associated stiffness of the interface are discussed. Applied Sciences 2016-05-25 6 6 Article 10.3390/app6060163 163 2076-3417 2016-05-25 doi: 10.3390/app6060163 Sanichiro Yoshida David Didie Daniel Didie Tomohiro Sasaki Hae-Sung Park Ik-Keun Park David Gurney http://www.mdpi.com/2076-3417/6/6/159 Poly(vinylidene fluoride) (PVDF) was modified with a styrene-based copolymer. The crystalline behavior, phase, thermal stability, and surface morphology of the modified membranes were analyzed. The membrane surface roughness showed a strong dependence on the styrene-acrylonitrile content and was reduced to 34% for a PVDF/styrene-acrylonitrile blend membrane with a 40/60 ratio. The thermal and crystalline behavior confirmed the blend miscibility of both polymers. It was observed in X-ray diffraction (XRD) experiments that the modified PVDF membranes show a drastic reduction in their crystallinity. The neat PVDF membrane has the highest degradation rate, which decreased with the addition of the styrene-based copolymer. Applied Sciences 2016-05-24 6 6 Article 10.3390/app6060159 159 2076-3417 2016-05-24 doi: 10.3390/app6060159 Harsha Srivastava Harshad Lade Diby Paul G. Arthanareeswaran Ji Kweon http://www.mdpi.com/2076-3417/6/6/160 Multi-instance multi-label learning is a learning framework, where every object is represented by a bag of instances and associated with multiple labels simultaneously. The existing degeneration strategy-based methods often suffer from some common drawbacks: (1) the user-specific parameter for the number of clusters may incur the effective problem; (2) SVM may bring a high computational cost when utilized as the classifier builder. In this paper, we propose an algorithm, namely multi-instance multi-label (MIML)-extreme learning machine (ELM), to address the problems. To our best knowledge, we are the first to utilize ELM in the MIML problem and to conduct the comparison of ELM and SVM on MIML. Extensive experiments have been conducted on real datasets and synthetic datasets. The results show that MIMLELM tends to achieve better generalization performance at a higher learning speed. Applied Sciences 2016-05-24 6 6 Article 10.3390/app6060160 160 2076-3417 2016-05-24 doi: 10.3390/app6060160 Ying Yin Yuhai Zhao Chengguang Li Bin Zhang http://www.mdpi.com/2076-3417/6/6/158 In this paper, a reactive power optimization method based on historical data is investigated to solve the dynamic reactive power optimization problem in distribution network. In order to reflect the variation of loads, network loads are represented in a form of random matrix. Load similarity (LS) is defined to measure the degree of similarity between the loads in different days and the calculation method of the load similarity of load random matrix (LRM) is presented. By calculating the load similarity between the forecasting random matrix and the random matrix of historical load, the historical reactive power optimization dispatching scheme that most matches the forecasting load can be found for reactive power control usage. The differences of daily load curves between working days and weekends in different seasons are considered in the proposed method. The proposed method is tested on a standard 14 nodes distribution network with three different types of load. The computational result demonstrates that the proposed method for reactive power optimization is fast, feasible and effective in distribution network. Applied Sciences 2016-05-24 6 6 Article 10.3390/app6060158 158 2076-3417 2016-05-24 doi: 10.3390/app6060158 Wanxing Sheng Keyan Liu Hongyan Pei Yunhua Li Dongli Jia Yinglong Diao http://www.mdpi.com/2076-3417/6/5/157 In this paper, we propose a method called temporal correlation support vector machine (TCSVM) for automatic major-minor chord recognition in audio music. We first use robust principal component analysis to separate the singing voice from the music to reduce the influence of the singing voice and consider the temporal correlations of the chord features. Using robust principal component analysis, we expect the low-rank component of the spectrogram matrix to contain the musical accompaniment and the sparse component to contain the vocal signals. Then, we extract a new logarithmic pitch class profile (LPCP) feature called enhanced LPCP from the low-rank part. To exploit the temporal correlation among the LPCP features of chords, we propose an improved support vector machine algorithm called TCSVM. We perform this study using the MIREX'09 (Music Information Retrieval Evaluation eXchange) Audio Chord Estimation dataset. Furthermore, we conduct comprehensive experiments using different pitch class profile feature vectors to examine the performance of TCSVM. The results of our method are comparable to the state-of-the-art methods that entered the MIREX in 2013 and 2014 for the MIREX'09 Audio Chord Estimation task dataset. Applied Sciences 2016-05-19 6 5 Article 10.3390/app6050157 157 2076-3417 2016-05-19 doi: 10.3390/app6050157 Zhongyang Rao Xin Guan Jianfu Teng http://www.mdpi.com/2076-3417/6/5/156 This paper presents a micro-coordinate measuring machine (micro-CMM) for large-scale dimensional measurement of a micro-slit on a precision die coater by using a shear-mode micro-probe. A glass micro sphere with a nominal diameter of 52.3 μm was attached on one end of a tapered glass capillary tube as a probe tip ball. The micro-slit width of a slot die coater with a nominal slit width of 85 μm was measured by the micro-CMM. The probe tip was placed in the slit for the measurement. The effective working length of the probe was confirmed experimentally to be at least 1 mm. In order to measure the gap width uniformity over the entire slot die length of 200 mm, an air-bearing linear slide with a travelling stroke of 300 mm was employed in the micro-CMM to position the probe along the length direction of the slot die. The angular alignment error and the motion error of the air-bearing linear slide as well as those of the stages for positioning the probe along the direction perpendicular to the length direction of the slot die were investigated for evaluation of the expanded uncertainty of gap width measurement. Applied Sciences 2016-05-18 6 5 Article 10.3390/app6050156 156 2076-3417 2016-05-18 doi: 10.3390/app6050156 So Ito Hirotaka Kikuchi Yuanliu Chen Yuki Shimizu Wei Gao Kazuhiko Takahashi Toshihiko Kanayama Kunmei Arakawa Atsushi Hayashi http://www.mdpi.com/2076-3417/6/5/148 Reservoir sedimentation and its effect on the environment are the most serious world-wide problems in water resources development and utilization today. As one of the largest water conservancy projects, the Three Gorges Reservoir (TGR) has been controversial since its demonstration period, and sedimentation is the major concern. Due to the complex physical mechanisms of water and sediment transport, this study adopts the Error Back Propagation Training Artificial Neural Network (BP-ANN) to analyze the relationship between the sediment flushing efficiency of the TGR and its influencing factors. The factors are determined by the analysis on 1D unsteady flow and sediment mathematical model, mainly including reservoir inflow, incoming sediment concentration, reservoir water level, and reservoir release. Considering the distinguishing features of reservoir sediment delivery in different seasons, the monthly average data from 2003, when the TGR was put into operation, to 2011 are used to train, validate, and test the BP-ANN model. The results indicate that, although the sample space is quite limited, the whole sediment delivery process can be schematized by the established BP-ANN model, which can be used to help sediment flushing and thus decrease the reservoir sedimentation. Applied Sciences 2016-05-18 6 5 Article 10.3390/app6050148 148 2076-3417 2016-05-18 doi: 10.3390/app6050148 Xueying Li Jun Qiu Qianqian Shang Fangfang Li http://www.mdpi.com/2076-3417/6/5/155 Toxicity testing in populations probes for responses in demographic variables to anthropogenic or natural chemical changes in the environment. Importantly, these tests are primarily performed on species in isolation of adjacent tropic levels in their ecosystem. The development and validation of coupled species models may aid in predicting adverse outcomes at the ecosystems level. Here, we aim to validate a model for the population dynamics of the green algae Raphidocelis subcapitata, a planktonic species that is often used as a primary food source in toxicity experiments for the fresh water crustacean Daphnia magna. We collected longitudinal data from three replicate population experiments of R. subcapitata. We used this data with statistical model comparison tests and uncertainty quantification techniques to compare the performance of four models: the Logistic model, the Bernoulli model, the Gompertz model, and a discretization of the Logistic model. Overall, our results suggest that the logistic model is the most accurate continuous model for R. subcapitata population growth. We then implement the numerical discretization showing how the continuous logistic model for algae can be coupled to a previously validated discrete-time population model for D. magna. Applied Sciences 2016-05-18 6 5 Article 10.3390/app6050155 155 2076-3417 2016-05-18 doi: 10.3390/app6050155 Michael Stemkovski Robert Baraldi Kevin Flores H.T. Banks http://www.mdpi.com/2076-3417/6/5/154 Singular value decomposition (SVD) is a widely used and powerful tool for signal extraction under noise. Noise attenuation relies on the selection of the effective singular value because these values are significant features of the useful signal. Traditional methods of selecting effective singular values (or selecting the useful components to rebuild the faulty signal) consist of seeking the maximum peak of the differential spectrum of singular values. However, owing to the small number of selected effective singular values, these methods lead to excessive de-noised effects. In order to get a more appropriate number of effective singular values, which preserves the components of the original signal as much as possible, this paper used a difference curvature spectrum of incremental singular entropy to determine the number of effective singular values. Then the position was found where the difference of two peaks in the spectrum declines in an infinitely large degree for the first time, and this position was regarded as the boundary of singular values between noise and a useful signal. The experimental results showed that the modified methods could accurately extract the non-stationary bearing faulty signal under real background noise. Applied Sciences 2016-05-18 6 5 Article 10.3390/app6050154 154 2076-3417 2016-05-18 doi: 10.3390/app6050154 Jie Gao Lifeng Wu Hongmin Wang Yong Guan http://www.mdpi.com/2076-3417/6/5/151 A non-smooth switched harvest on predators is introduced into a simple predator-prey model with logistical growth of the prey and a bilinear functional response. If the density of the predator is below a switched value, the harvesting rate is linear; otherwise, it is constant. The model links the well studied predator-prey model with constant harvesting to that with a proportional harvesting rate. It is shown that when the net reproductive number for the predator is greater than unity, the system is permanent and there may exist multiple positive equilibria due to the effects of the switched harvest, a saddle-node bifurcation, a limit cycle, and the coexistence of a stable equilibrium and a unstable circled inside limit cycle and a stable circled outside limit cycle. When the net reproductive number is less than unity, a backward bifurcation from a positive equilibrium occurs, which implies that the stable predator-extinct equilibrium may coexist with two coexistence equilibria. In this situation, reducing the net reproductive number to less than unity is not enough to enable the predator to go extinct. Numerical simulations are provided to illustrate the theoretical results. It seems that the model possesses new complex dynamics compared to the existing harvesting models. Applied Sciences 2016-05-16 6 5 Article 10.3390/app6050151 151 2076-3417 2016-05-16 doi: 10.3390/app6050151 Bing Li Shengqiang Liu Jing'an Cui Jia Li http://www.mdpi.com/2076-3417/6/5/149 Quorum sensing is a bacterial cell-to-cell communication mechanism and is based on gene regulatory networks, which control and regulate the production of signaling molecules in the environment. In the past years, mathematical modeling of quorum sensing has provided an understanding of key components of such networks, including several feedback loops involved. This paper presents a simple system of delay differential equations (DDEs) for quorum sensing of Pseudomonas putida with one positive feedback plus one (delayed) negative feedback mechanism. Results are shown concerning fundamental properties of solutions, such as existence, uniqueness, and non-negativity; the last feature is crucial for mathematical models in biology and is often violated when working with DDEs. The qualitative behavior of solutions is investigated, especially the stationary states and their stability. It is shown that for a certain choice of parameter values, the system presents stability switches with respect to the delay. On the other hand, when the delay is set to zero, a Hopf bifurcation might occur with respect to one of the negative feedback parameters. Model parameters are fitted to experimental data, indicating that the delay system is sufficient to explain and predict the biological observations. Applied Sciences 2016-05-16 6 5 Article 10.3390/app6050149 149 2076-3417 2016-05-16 doi: 10.3390/app6050149 Maria Barbarossa Christina Kuttler http://www.mdpi.com/2076-3417/6/5/150 Micro parts are increasingly found in a number of industrial products. They often have complex geometrical features in the millimeter to micrometer range which are not accessible or difficult to measure by conventional coordinate measuring machines or by optical microscopy techniques. In the last years, several concepts of tactile micro coordinate measuring machines have been developed in research laboratories and were partly commercialized by industry. The major challenges were related to the development of innovative micro probes, to the requirements for traceability and to the performance assessment at reduced measurement uncertainty. This paper presents a review on state of the art developments of micro coordinate measuring machines and 3D micro probes in the last 20 years, as far as these were qualified in a comparable way, with a special emphasis on research conducted by the Federal Institute of Metrology METAS in this field. It outlines the accuracy limitations for the probe head including the probing element and for the geometrical errors of the machine axes. Finally, the achieved performances are summarized and the challenges for further research are addressed. Applied Sciences 2016-05-16 6 5 Review 10.3390/app6050150 150 2076-3417 2016-05-16 doi: 10.3390/app6050150 Rudolf Thalmann Felix Meli Alain Küng http://www.mdpi.com/2076-3417/6/5/152 Lotus flowers, rose petals, some plant leaves and insects have a naturally super-hydrophobic surface. In fact, the surface of a Lotus leaf is covered by micro and nano structures mixed with wax, which makes its surface superhydrophobic. In microfluidics, superhydrophobicity is an important factor in the rheometers on a chip. It is also sought in other complex fluids applications like the self-cleaning and the antibacterial materials. The wettability of the surface of solid support can be modified by altering its chemical composition. This means functionalizing the interface molecules to different chemical properties, and/or forming a thin film on the surface. We can also influence its texturing by changing its roughness. Despite considerable efforts during the last decade, superhydrophobic surfaces usually involve, among others, microfabrication processes, such as photolithography technique. In this study, we propose an original and simple method to create superhydrophobic surfaces by controlling elastic instability of poly-dimethylsiloxane (PDMS) films. Indeed, we demonstrate that the self-organization of wrinkles on top of non-wettable polymer surfaces leads to surperhydrophobic surfaces with contact angles exceeding 150°. We studied the transition Wenzel-Cassie, which indicated that the passage of morphology drops "impaled" to a type of morphology "fakir" were the strongest topographies. Applied Sciences 2016-05-16 6 5 Article 10.3390/app6050152 152 2076-3417 2016-05-16 doi: 10.3390/app6050152 Abbas Sabbah Ayman Youssef Pascal Damman http://www.mdpi.com/2076-3417/6/5/153 Recent years have witnessed an increased demand for a method for precise measurement of the microstructures of mechanical microparts, microelectromechanical systems, micromolds, optical devices, microholes, etc. This paper presents a measurement system for three-dimensional (3D) microstructures that use an optical fiber probe. This probe consists of a stylus shaft with a diameter of 2.5 µm and a glass ball with a diameter of 5 µm attached to the stylus tip. In this study, the measurement system, placed in a vacuum vessel, is constructed suitably to prevent adhesion of the stylus tip to the measured surface caused by the surface force resulting from the van der Waals force, electrostatic force, and liquid bridge force. First, these surface forces are analyzed with the aim of investigating the causes of adhesion. Subsequently, the effects of pressure inside the vacuum vessel on surface forces are evaluated. As a result, it is found that the surface force is 0.13 µN when the pressure inside the vacuum vessel is 350 Pa. This effect is equivalent to a 60% reduction in the surface force in the atmosphere. Applied Sciences 2016-05-16 6 5 Article 10.3390/app6050153 153 2076-3417 2016-05-16 doi: 10.3390/app6050153 Hiroshi Murakami Akio Katsuki Takao Sajima Mitsuyoshi Fukuda http://www.mdpi.com/2076-3417/6/5/143 Endowing machines with sensing capabilities similar to those of humans is a prevalent quest in engineering and computer science. In the pursuit of making computers sense their surroundings, a huge effort has been conducted to allow machines and computers to acquire, process, analyze and understand their environment in a human-like way. Focusing on the sense of hearing, the ability of computers to sense their acoustic environment as humans do goes by the name of machine hearing. To achieve this ambitious aim, the representation of the audio signal is of paramount importance. In this paper, we present an up-to-date review of the most relevant audio feature extraction techniques developed to analyze the most usual audio signals: speech, music and environmental sounds. Besides revisiting classic approaches for completeness, we include the latest advances in the field based on new domains of analysis together with novel bio-inspired proposals. These approaches are described following a taxonomy that organizes them according to their physical or perceptual basis, being subsequently divided depending on the domain of computation (time, frequency, wavelet, image-based, cepstral, or other domains). The description of the approaches is accompanied with recent examples of their application to machine hearing related problems. Applied Sciences 2016-05-12 6 5 Review 10.3390/app6050143 143 2076-3417 2016-05-12 doi: 10.3390/app6050143 Francesc Alías Joan Socoró Xavier Sevillano http://www.mdpi.com/2076-3417/6/5/147 The use of plastic film in agriculture has the serious drawback of producing vast quantities of waste. In this work, films were prepared from natural fibers and biodegradable polymers as potential substitutes for the conventional non-biodegradable plastic film used as mulching material in agricultural production. The physical properties (e.g., mechanical properties, heat preservation, water permeability, and photopermeability) and degradation characteristics (evaluated by micro-organic culture testing and soil burial testing) of the films were studied in both laboratory and field tests. The experimental results indicated that these fiber/polymer films exhibited favorable physical properties that were sufficient for use in mulching film applications. Moreover, the degradation degree of the three tested films decreased in the following order: fiber/starch (ST) film > fiber/poly(vinyl alcohol) (PVA) film > fiber/polyacrylate (PA) film. The fiber/starch and fiber/PVA films were made from completely biodegradable materials and demonstrated the potential to substitute non-biodegradable films. Applied Sciences 2016-05-12 6 5 Article 10.3390/app6050147 147 2076-3417 2016-05-12 doi: 10.3390/app6050147 Zhijian Tan Yongjian Yi Hongying Wang Wanlai Zhou Yuanru Yang Chaoyun Wang http://www.mdpi.com/2076-3417/6/5/142 This paper presents a novel brain-computer interface (BCI)-based healthcare control system, which is based on steady-state visually evoked potential (SSVEP) and P300 of electroencephalography (EEG) signals. The proposed system is composed of two modes, a brain switching mode and a healthcare function selection mode. The switching mode can detect whether a user has the intent to activate the function selection mode by detecting SSVEP in an ongoing EEG. During the function selection mode, the user is able to select any functions that he/she wants to activate through a healthcare control panel, and the function selection is done by detecting P300 in the user's EEG signals. The panel provides 25 functions representing 25 frequently performed activities of daily life. Therefore, users with severe motor disabilities can activate the system and any functions in a self-paced manner, achieving the goal of autonomous healthcare. To achieve high P300 detection accuracy, a novel P300 detector based on kernel Fisher's discriminant analysis (kernel FDA) and support vector machine (SVM) is also proposed. Experimental results, carried out on five subjects, show that the proposed BCI system achieves high SSVEP detection (93%) and high P300 detection (95.5%) accuracies, meaning that the switching mode has a high sensitivity, and the function selection mode has the ability to accurately detect the functions that the users want to trigger. More important, only three electrodes (Oz, Cz, and Pz) are required to measure EEG signals, enabling the system to have good usability in practical use. Applied Sciences 2016-05-12 6 5 Article 10.3390/app6050142 142 2076-3417 2016-05-12 doi: 10.3390/app6050142 Yi-Hung Liu Shih-Hao Wang Ming-Ren Hu http://www.mdpi.com/2076-3417/6/5/145 A gas and coal dust explosion is potential hazard in majority coal mines. A coal mine mobile refuge chamber is a new class of device for miners those who are unable to escape after an accident which can provide basic survival conditions. In this paper, in order to study the propagation law of an underground methane/air mixture explosive wave, and check the failure mode of a coal mine mobile refuge chamber, a full-sized underground tunnel model and a refuge chamber model have been established in ANSYS/LS-DYNA (LSTC, R7.0.0, Livermore, CA, USA, 2014). The simulation results show that the reflected wave pressure on the front surface of the refuge chamber was about twice as high than the incident wave. The pressure on various locations of the chamber was also analyzed. When the peak pressure of the explosive shockwave reached 0.64 MPa, the maximum displacement and stress occur at the center of the front door and the joint of stiffeners and the front plate, respectively. Most parts of the coal mine mobile refuge chamber were in a plastic failure state and the refuge chamber could be defined as damaged. The front door, the front plate, the connecting flange, and the stiffeners on each side were the primary key components. In the end, suggestions were proposed for the refuge chamber. Applied Sciences 2016-05-11 6 5 Article 10.3390/app6050145 145 2076-3417 2016-05-11 doi: 10.3390/app6050145 Boyi Zhang Dongxian Zhai Wei Wang http://www.mdpi.com/2076-3417/6/5/144 Simulative methods are nowadays frequently used in metrology for the simulation of measurement uncertainty and the prediction of errors that may occur during measurements. In coordinate metrology, such methods are primarily used with the typical three-axis Coordinate Measuring Machines (CMMs), and lately, also with mobile measuring systems. However, no similar simulative models have been developed for five-axis systems in spite of their growing popularity in recent years. This paper presents the numerical model of probe head errors for probe heads that are used in five-axis coordinate systems. The model is based on measurements of material standards (standard ring) and the use of the Monte Carlo method combined with select interpolation methods. The developed model may be used in conjunction with one of the known models of CMM kinematic errors to form a virtual model of a five-axis coordinate system. In addition, the developed methodology allows for the correction of identified probe head errors, thus improving measurement accuracy. Subsequent verification tests prove the correct functioning of the presented model. Applied Sciences 2016-05-11 6 5 Article 10.3390/app6050144 144 2076-3417 2016-05-11 doi: 10.3390/app6050144 Adam Gąska Piotr Gąska Maciej Gruza http://www.mdpi.com/2076-3417/6/5/146 This paper proposes, for low buildings, an integrated wall structure of a brick-stem-insulating layer, which plays a major part in both heat preservation and force bearing. The research team has tested the thermal performance of the structure, the results of which are satisfying. To further study the force-bearing performance, the paper carries out compressive tests of specimens of different structural design, with two types of bricks, i.e., clay and recycled concrete bricks; three types of stems, i.e., square-shaped wood, square-shaped steel pipe and circular steel pipe; and one type of insulating layer, i.e., fly ash masonry blocks. Afterward, the force bearing performance, damage that occurred, compressive deformation and ductility of all of the specimens are compared. On the sideline, the structure is applied in the construction of a pilot residence project, yielding favorable outcomes. The results indicate that in comparison with a brick wall with an insulating layer sandwiched in between, the integrated wall structure of bricks and fly ash blocks is a more preferable choice in terms of compressive performance and ductility. The integrated wall structure of brick-stem-fly ash blocks delivers much better performance to this end. Note that regarding the stem's contribution to compressive strength, circular steel pipe is highest, followed by square-shaped steel pipe and then square-shaped wood. The compressive performance of the sandwiched blocks surpasses that of the two brick wall pieces combined by a large margin. Applied Sciences 2016-05-11 6 5 Article 10.3390/app6050146 146 2076-3417 2016-05-11 doi: 10.3390/app6050146 Suizi Jia Yan Liu Wanlin Cao Zhongyi Zhou Yuchen Zhang http://www.mdpi.com/2076-3417/6/5/141 The fluid-structure interaction problems of two side-by-side flexible plates with a finite aspect ratio in a three-dimensional (3D) uniform flow are numerically studied. The plates' motions are entirely passive under the force of surrounding fluid. By changing the aspect ratio and transverse distance, the coupling motions, drag force and energy capture performance are analyzed. The mechanisms underlying the plates' motion and flow characteristics are discussed systematically. The adopted algorithm is verified and validated by the simulation of flow past a square flexible plate. The results show that the plate's passive flapping behavior contains transverse and spanwise deformation, and the flapping amplitude is proportional to the aspect ratio. In the side-by-side configuration, three distinct coupling modes of the plates' motion are identified, including single-plate mode, symmetrical flapping mode and decoupled mode. The plate with a lower aspect ratio may suffer less drag force and capture less bending energy than in the isolated situation. The optimized selection for obtaining higher energy conversion efficiency is the plate flapping in single-plate mode, especially the plate with a higher aspect ratio. The findings of this work provide several new physical insights into the understanding of fish schooling and are expected to inspire the developments of underwater robots or energy harvesters. Applied Sciences 2016-05-10 6 5 Article 10.3390/app6050141 141 2076-3417 2016-05-10 doi: 10.3390/app6050141 Dibo Dong Weishan Chen Shengjun Shi http://www.mdpi.com/2076-3417/6/5/135 Recent bowed string sound synthesis has relied on physical modelling techniques; the achievable realism and flexibility of gestural control are appealing, and the heavier computational cost becomes less significant as technology improves. A bowed string sound synthesis algorithm is designed, by simulating two-polarisation string motion, discretising the partial differential equations governing the string's behaviour with the finite difference method. A globally energy balanced scheme is used, as a guarantee of numerical stability under highly nonlinear conditions. In one polarisation, a nonlinear contact model is used for the normal forces exerted by the dynamic bow hair, left hand fingers, and fingerboard. In the other polarisation, a force-velocity friction curve is used for the resulting tangential forces. The scheme update requires the solution of two nonlinear vector equations. The dynamic input parameters allow for simulating a wide range of gestures; some typical bow and left hand gestures are presented, along with synthetic sound and video demonstrations. Applied Sciences 2016-05-10 6 5 Article 10.3390/app6050135 135 2076-3417 2016-05-10 doi: 10.3390/app6050135 Charlotte Desvages Stefan Bilbao http://www.mdpi.com/2076-3417/6/5/134 Many systems featuring nonlinearities and delay-free loops are of interest in digital audio, particularly in virtual analog and physical modeling applications. Many of these systems can be posed as systems of implicitly related ordinary differential equations. Provided each equation in the network is itself an explicit one, straightforward numerical solvers may be employed to compute the output of such systems without resorting to linearization or matrix inversions for every parameter change. This is a cheap and effective means for synthesizing delay-free, nonlinear systems without resorting to large lookup tables, iterative methods, or the insertion of fictitious delay and is therefor suitable for real-time applications. Several examples are shown to illustrate the efficacy of this approach. Applied Sciences 2016-05-10 6 5 Article 10.3390/app6050134 134 2076-3417 2016-05-10 doi: 10.3390/app6050134 David Medine http://www.mdpi.com/2076-3417/6/5/140 This paper proposes a novel image alignment algorithm based on rotation-discriminating ring-shifted projection for automatic optical inspection. This new algorithm not only identifies the location of the template image within an inspection image but also provides precise rotation information during the template-matching process by using a novel rotation estimation scheme, the so-called ring-shifted technique. We use a two stage framework with an image pyramid searching technique for realizing the proposed image alignment algorithm; in the first stage, the similarity based on hybrid projection transformation with the image pyramid searching technique is employed for quick selection and location of the candidates in the inspection image. In the second stage, the rotation angle of the object is estimated by a novel ring-shifted technique. The estimation is performed only for the most likely candidate which is the one having the highest similarity in the first stage. The experimental results show that the proposed method provides accurate estimation for template matching with arbitrary rotations and is applicable in various environmental conditions. Applied Sciences 2016-05-09 6 5 Article 10.3390/app6050140 140 2076-3417 2016-05-09 doi: 10.3390/app6050140 Chin-Sheng Chen Chien-Liang Huang http://www.mdpi.com/2076-3417/6/5/137 This study presents a new method to track driver's facial states, such as head pose and eye-blinking in the real-time basis. Since a driver in the natural driving condition moves his head in diverse ways and his face is often occluded by his hand or the wheel, it should be a great challenge for the standard face models. Among many, Active Appearance Model (AAM), and Active Shape Model (ASM) are two favored face models. We have extended Discriminative Bayesian ASM by incorporating the extreme pose cases, called it Pose Extended—Active Shape model (PE-ASM). Two face databases (DB) are used for the comparison purpose: one is the Boston University face DB and the other is our custom-made driving DB. Our evaluation indicates that PE-ASM outperforms ASM and AAM in terms of the face fitting against extreme poses. Using this model, we can estimate the driver's head pose, as well as eye-blinking, by adding respective processes. Two HMMs are trained to model temporal behaviors of these two facial features, and consequently the system can make inference by enumerating these HMM states whether the driver is drowsy or not. Result suggests that it can be used as a driver drowsiness detector in the commercial car where the visual conditions are very diverse and often tough to deal with. Applied Sciences 2016-05-07 6 5 Article 10.3390/app6050137 137 2076-3417 2016-05-07 doi: 10.3390/app6050137 In-Ho Choi Chan-Hee Jeong Yong-Guk Kim http://www.mdpi.com/2076-3417/6/5/138 To improve electrical distribution network reliability, some portions of the network could operate in autonomous mode, provided that the related technical issues are addressed. More specifically, when there is not a path from those portions to the primary substation due to a fault in the network, such portions could be disconnected from the main network and supplied by local generation only. Such a mode of operation is known as "intentional islanding" and its effectiveness, in terms of adequacy, depends on the ability of the local generation to meet the island's load. In fact, the ratio between the available local generation and load demand can frequently change during islanding due to load variations and, especially, due to the strongly irregular behavior of the primary energy sources of renewable generators. This paper proposes an analytical formulation to assess local generation adequacy during intentional islanding, accounting for the aforementioned variations. More specifically, the fluctuations of load and green-energy generators during islanding are modeled by means of Markov chains, whose output quantities are encompassed in the proposed analytical formulation. Such a formulation is used by the analytical equations of load points' outage rate and duration. The evaluation of the reliability indices accounts for a protection scheme based on an appropriate communication infrastructure. Therefore, a brief overview on the telecommunications technologies has been presented with reference to their suitability for the specific application. In particular, distribution network safety issues have been considered as the main concern. The results show that neglecting load and generation fluctuations leads to a strong overestimation of the ability of distributed generators to meet the island load. Through a case study it is observed that the error on the load point outage rate is greater than the one affecting the outage duration. Applied Sciences 2016-05-07 6 5 Article 10.3390/app6050138 138 2076-3417 2016-05-07 doi: 10.3390/app6050138 Stefania Conti Giuseppe Faraci Aurelio La Corte Rosario Nicolosi Santi Rizzo Giovanni Schembra http://www.mdpi.com/2076-3417/6/5/139 Helicobacter pylori is a spiral-shaped bacterium that grows in the human digestive tract; it infects ~50% of the global population. H. pylori induce inflammation, gastroenteritis, and ulcers, which is associated with significant morbidity and may be linked to stomach cancer in certain individuals. Motility is an essential virulence factor for H. pylori, allowing it to migrate toward and invade the epithelial lining of the stomach to shelter it from the harsh environment of the stomach. H. pylori senses pH gradients and use polar flagella to move towards the epithelium where the pH approaches neutrality. However, its chemotaxis behaviors are incompletely understood. Previous in vitro tests examining the response of H. pylori to chemical gradients have been subjected to substantial limitations. To more accurately mimic/modulate the cellular microenvironment, a nanoporous microfluidic device was used to monitor the real time chemotactic activity of single cell of H. pylori in response to urea. The results showed that microfluidic method is a promising alternative for accurate studying of chemotactic behavior of H. pylori, the application of which may also be extended in the studies of other bacteria. Applied Sciences 2016-05-07 6 5 Article 10.3390/app6050139 139 2076-3417 2016-05-07 doi: 10.3390/app6050139 Xuan Weng Suresh Neethirajan Adam Vogt http://www.mdpi.com/2076-3417/6/5/136 A simple method was proposed for on-site evaluation of the pulse width of an ultraviolet femtosecond laser coupled with a mass spectrometer. This technique was based on measurement of a two-photon ionization signal in mass spectrometry by translation of the prism in the pulse compressor of the femtosecond laser. The method was applied to optical pulses that were emitted at wavelengths of 267, 241, and 219 nm; the latter two pulses were generated by four-wave Raman mixing using the third harmonic emission of a Ti:sapphire laser (267 nm) in hydrogen gas. The measurement results show that this approach is useful for evaluation of the pulse width of the ultraviolet femtosecond laser used in mass spectrometry for trace analysis of organic compounds. Applied Sciences 2016-05-06 6 5 Article 10.3390/app6050136 136 2076-3417 2016-05-06 doi: 10.3390/app6050136 Tomoko Imasaka Akifumi Hamachi Tomoya Okuno Totaro Imasaka http://www.mdpi.com/2076-3417/6/5/129 Audio equalization is a vast and active research area. The extent of research means that one often cannot identify the preferred technique for a particular problem. This review paper bridges those gaps, systemically providing a deep understanding of the problems and approaches in audio equalization, their relative merits and applications. Digital signal processing techniques for modifying the spectral balance in audio signals and applications of these techniques are reviewed, ranging from classic equalizers to emerging designs based on new advances in signal processing and machine learning. Emphasis is placed on putting the range of approaches within a common mathematical and conceptual framework. The application areas discussed herein are diverse, and include well-defined, solvable problems of filter design subject to constraints, as well as newly emerging challenges that touch on problems in semantics, perception and human computer interaction. Case studies are given in order to illustrate key concepts and how they are applied in practice. We also recommend preferred signal processing approaches for important audio equalization problems. Finally, we discuss current challenges and the uncharted frontiers in this field. The source code for methods discussed in this paper is made available at https://code.soundsoftware.ac.uk/projects/allaboutaudioeq. Applied Sciences 2016-05-06 6 5 Review 10.3390/app6050129 129 2076-3417 2016-05-06 doi: 10.3390/app6050129 Vesa Välimäki Joshua Reiss http://www.mdpi.com/2076-3417/6/5/132 The paper is concerned with the problem of multi-view three-dimensional (3D) point cloud registration. A novel global registration method is proposed to accurately register two series of scans into an object model underlying 3D imaging digitization by using the proposed oriented bounding box (OBB) regional area-based descriptor. A robot 3D scanning strategy is nowadays employed to generate the complete set of point cloud of physical objects by using 3D robot multi-view scanning and data registration. The automated operation has to successively digitize view-dependent area-scanned point cloud from complex-shaped objects by simultaneous determination of the next best robot pose and multi-view point cloud registration. To achieve this, the OBB regional area-based descriptor is employed to determine an initial transformation matrix and is then refined employing the iterative closest point (ICP) algorithm. The key technical breakthrough can resolve the commonly encountered difficulty in accurately merging two neighboring area-scanned images when no coordinate reference exists. To verify the effectiveness of the strategy, the developed method has been verified through some experimental tests for its registration accuracy. Experimental results have preliminarily demonstrated the feasibility and applicability of the developed method. Applied Sciences 2016-05-05 6 5 Article 10.3390/app6050132 132 2076-3417 2016-05-05 doi: 10.3390/app6050132 Liang-Chia Chen Dinh-Cuong Hoang Hsien-I Lin Thanh-Hung Nguyen http://www.mdpi.com/2076-3417/6/5/133 The recycled Kevlar®/polyester/low-melting-point polyester (recycled Kevlar®/PET/LPET) nonwoven geotextiles are immersed in neutral, strong acid, and strong alkali solutions, respectively, at different temperatures for four months. Their tensile strength is then tested according to various immersion periods at various temperatures, in order to determine their durability to chemicals. For the purpose of analyzing the possible factors that influence mechanical properties of geotextiles under diverse environmental conditions, the experimental results and statistical analyses are incorporated in this study. Therefore, influences of the content of recycled Kevlar® fibers, implementation of thermal treatment, and immersion periods on the tensile strength of recycled Kevlar®/PET/LPET nonwoven geotextiles are examined, after which their influential levels are statistically determined by performing multiple regression analyses. According to the results, the tensile strength of nonwoven geotextiles can be enhanced by adding recycled Kevlar® fibers and thermal treatment. Applied Sciences 2016-05-05 6 5 Article 10.3390/app6050133 133 2076-3417 2016-05-05 doi: 10.3390/app6050133 Jing-Chzi Hsieh Jia-Hsun Li Ching-Wen Lou Chien-Teng Hsieh Wen-Hao Hsing Yi-Jun Pan Jia-Horng Lin http://www.mdpi.com/2076-3417/6/5/131 The effects of transition metals on the hydrophobicity of nano–structured layered double hydroxides (LDHs) and the compatibility of LDHs/ethylene vinyl acetate (EVA) composites have seldom been reported. NiMgAl–LDHs slightly surface–modified with stearate and doped with transition metal cations (Mn2+, Co2+, Cu2+, Zn2+) are investigated. Compared to the pure EVA, not only were the maximal degradation–rate temperatures (Tmax) of the ethylene–based chains enhanced, but also the smoke production rate (SPR) and the production rate of CO (COP) were sharply decreased for all the composites. Most importantly, a new flame retardant mechanism was found, namely the peak heat release rate (pk-HRR) time, which directly depends on the peak production rate of CO2 (pk-CO2) time for EVA and all composites by cone calorimeter test. Moreover, the Mn–doped LDH S–NiMgAl–Mn shows more uniform dispersion and better interfacial compatibility in the EVA matrix. The cone calorimetric residue of S–NiMgAl–Mn/EVA has the intumescent char layer and the compact metal oxide layer. Therefore, S–NiMgAl–Mn/EVA shows the lowest pk-HRR and the longest pk-HRR time among all the composites. Applied Sciences 2016-05-04 6 5 Article 10.3390/app6050131 131 2076-3417 2016-05-04 doi: 10.3390/app6050131 Lili Wang Milin Zhang Bin Li http://www.mdpi.com/2076-3417/6/5/123 The practice of harmonic mixing is a technique used by DJs for the beat-synchronous and harmonic alignment of two or more pieces of music. In this paper, we present a new harmonic mixing method based on psychoacoustic principles. Unlike existing commercial DJ-mixing software, which determines compatible matches between songs via key estimation and harmonic relationships in the circle of fifths, our approach is built around the measurement of musical consonance. Given two tracks, we first extract a set of partials using a sinusoidal model and average this information over sixteenth note temporal frames. By scaling the partials of one track over ±6 semitones (in 1/8th semitone steps), we determine the pitch-shift that maximizes the consonance of the resulting mix. For this, we measure the consonance between all combinations of dyads within each frame according to psychoacoustic models of roughness and pitch commonality. To evaluate our method, we conducted a listening test where short musical excerpts were mixed together under different pitch shifts and rated according to consonance and pleasantness. Results demonstrate that sensory roughness computed from a small number of partials in each of the musical audio signals constitutes a reliable indicator to yield maximum perceptual consonance and pleasantness ratings by musically-trained listeners. Applied Sciences 2016-05-03 6 5 Article 10.3390/app6050123 123 2076-3417 2016-05-03 doi: 10.3390/app6050123 Roman Gebhardt Matthew Davies Bernhard Seeber http://www.mdpi.com/2076-3417/6/5/130 This paper proposes the development of a two-axis sun tracking solar energy system using fuzzy logic as intelligent quality policy. To achieve maximum efficiency for solar panels, it is necessary to follow the sun's path in the sky. Therefore, the architecture for the two-axis sun tracking solar energy system uses software to control the hardware. The hardware comprises (i) solar cells; (ii) lead-acid batteries; (iii) a gear box; (iv) a stepping motor; and (v) a light detection circuit, while the software comprises (i) a detection system; (ii) a fuzzy tracking controller; and (iii) a database system. A fuzzy logic controller is designed as the software architecture of the system to decide the timing for tracking the sun. The nearest position that results in receiving direct sunlight is obtained from the database. Our system is fully automatic in a changing environment and takes into account meteorological changes and the effects of the external environment arising from a malfunction. This approach reduces the number of starting motors and results in smaller energy loss in cloudy, cloud mask, or unstable weather conditions. Applied Sciences 2016-05-03 6 5 Article 10.3390/app6050130 130 2076-3417 2016-05-03 doi: 10.3390/app6050130 Cong-Hui Huang Heng-Yau Pan Kuan-Chen Lin http://www.mdpi.com/2076-3417/6/5/126 This paper presents a case study on the rehabilitation of a fire-damaged structure and describes the results of a site investigation and tests, leading to a plan for the rehabilitation of the structure. The fire took place in the main control room of a thermal power plant and lasted about three hours until it was finally extinguished. To set up a rehabilitation plan for the damaged structure, a visual inspection of the damaged condition was first carried out, which was followed by analysis and on-site material tests indicating the degree of neutralization progress in the remaining structure. Specimens of damaged concrete and reinforcing bars were sampled and tested for their residual strengths. As a conclusion, two methods of rehabilitation were suggested considering the current condition of the structure and the sequence of construction. Applied Sciences 2016-05-02 6 5 Article 10.3390/app6050126 126 2076-3417 2016-05-02 doi: 10.3390/app6050126 Taehun Ha Jeongwon Ko Sangho Lee Seonwoong Kim Jieun Jung Dae-Jin Kim http://www.mdpi.com/2076-3417/6/5/128 We report a passively Q-switched Ho:YVO4 laser pumped at 1.94 µm with multilayer graphene as a saturable absorber. At the absorbed pump power of 9.3 W, the maximum average output power of 2.2 W was obtained in Ho:YVO4 laser with minimum pulse width of 265.2 ns and pulse repetition rate of 131.6 kHz at 2052.1 nm. In addition, a beam quality factor of M2~1.7 was measured at the maximum output level. This is, as far as we know, the first time that graphene has been used in a passively Q-switched Ho:YVO4 laser. Applied Sciences 2016-05-02 6 5 Letter 10.3390/app6050128 128 2076-3417 2016-05-02 doi: 10.3390/app6050128 Wenmiao Lin Xiaoming Duan Zheng Cui Baoquan Yao Tongyu Dai Xiaolei Li http://www.mdpi.com/2076-3417/6/5/127 Sinusoids are widely used to represent the oscillatory modes of musical instrument sounds in both analysis and synthesis. However, musical instrument sounds feature transients and instrumental noise that are poorly modeled with quasi-stationary sinusoids, requiring spectral decomposition and further dedicated modeling. In this work, we propose a full-band representation that fits sinusoids across the entire spectrum. We use the extended adaptive Quasi-Harmonic Model (eaQHM) to iteratively estimate amplitude- and frequency-modulated (AM–FM) sinusoids able to capture challenging features such as sharp attacks, transients, and instrumental noise. We use the signal-to-reconstruction-error ratio (SRER) as the objective measure for the analysis and synthesis of 89 musical instrument sounds from different instrumental families. We compare against quasi-stationary sinusoids and exponentially damped sinusoids. First, we show that the SRER increases with adaptation in eaQHM. Then, we show that full-band modeling with eaQHM captures partials at the higher frequency end of the spectrum that are neglected by spectral decomposition. Finally, we demonstrate that a frame size equal to three periods of the fundamental frequency results in the highest SRER with AM–FM sinusoids from eaQHM. A listening test confirmed that the musical instrument sounds resynthesized from full-band analysis with eaQHM are virtually perceptually indistinguishable from the original recordings. Applied Sciences 2016-05-02 6 5 Article 10.3390/app6050127 127 2076-3417 2016-05-02 doi: 10.3390/app6050127 Marcelo Caetano George Kafentzis Athanasios Mouchtaris Yannis Stylianou http://www.mdpi.com/2076-3417/6/5/125 Audio feedback is defined as a positive feedback of acoustic signals where an audio input and output form a loop, and may be utilized artistically. This article presents new context-based controls over audio feedback, leading to the generation of desired sonic behaviors by enriching the influence of existing acoustic information such as room response and ambient noise. This ecological approach to audio feedback emphasizes mutual sonic interaction between signal processing and the acoustic environment. Mappings from analyses of the received signal to signal-processing parameters are designed to emphasize this specificity as an aesthetic goal. Our feedback system presents four types of mappings: approximate analyses of room reverberation to tempo-scale characteristics, ambient noise to amplitude and two different approximations of resonances to timbre. These mappings are validated computationally and evaluated experimentally in different acoustic conditions. Applied Sciences 2016-04-28 6 5 Article 10.3390/app6050125 125 2076-3417 2016-04-28 doi: 10.3390/app6050125 Seunghun Kim Graham Wakefield Juhan Nam http://www.mdpi.com/2076-3417/6/5/122 Demand Side Management (DSM) through optimization of home energy consumption in the smart grid environment is now one of the well-known research areas. Appliance scheduling has been done through many different algorithms to reduce peak load and, consequently, the Peak to Average Ratio (PAR). This paper presents a Comprehensive Home Energy Management Architecture (CHEMA) with integration of multiple appliance scheduling options and enhanced load categorization in a smart grid environment. The CHEMA model consists of six layers and has been modeled in Simulink with an embedded MATLAB code. A single Knapsack optimization technique is used for scheduling and four different cases of cost reduction are modeled at the second layer of CHEMA. Fault identification and electricity theft control have also been added in CHEMA. Furthermore, carbon footprint calculations have been incorporated in order to make the users aware of environmental concerns. Simulation results prove the effectiveness of the proposed model. Applied Sciences 2016-04-28 6 5 Article 10.3390/app6050122 122 2076-3417 2016-04-28 doi: 10.3390/app6050122 Anzar Mahmood Faisal Baig Nabil Alrajeh Umar Qasim Zahoor Khan Nadeem Javaid http://www.mdpi.com/2076-3417/6/5/124 This work presents a practical active noise control system composed of distributed and collaborative acoustic nodes. To this end, experimental tests have been carried out in a listening room with acoustic nodes equipped with loudspeakers and microphones. The communication among the nodes is simulated by software. We have considered a distributed algorithm based on the Filtered-x Least Mean Square (FxLMS) method that introduces collaboration between nodes following an incremental strategy. For improving the processing efficiency in practical scenarios where data acquisition systems work by blocks of samples, the frequency-domain partitioned block technique has been used. Implementation aspects such as computational complexity, processing time of the network and convergence of the algorithm have been analyzed. Experimental results show that, without constraints in the network communications, the proposed distributed algorithm achieves the same performance as the centralized version. The performance of the proposed algorithm over a network with a given communication delay is also included. Applied Sciences 2016-04-28 6 5 Article 10.3390/app6050124 124 2076-3417 2016-04-28 doi: 10.3390/app6050124 Christian Antoñanzas Miguel Ferrer Maria de Diego Alberto Gonzalez http://www.mdpi.com/2076-3417/6/5/120 Apartment houses have been continuously constructed in Korea to solve overcrowding in large cities. The interlayer noise arising from these apartment houses has now become a critical social problem which requires an urgent solution. In recent years, studies applying numerical analysis techniques with respect to the structural type and floor plane have been carried out to effectively reduce the heavy weight impact noise, which is a cause for the interlayer noise. This study proposes analytical impact force models based on the actual measurement data regarding the heavy weight impact noise, which is mandatory input data for performing a numerical analysis. Additionally, the appropriateness of the proposed models has been verified through a comparative review with Korean standards. With the use of the proposed model, a numerical analysis has been conducted using a wall-type specimen, and a comparative analysis has been also performed with respect to the field measurement data. The applicability of the proposed model to the numerical analysis shows the possibility to resolve the interlayer noise problems numerically posing difficulties due to both the limited costs and time. Finally, it is expected that more information can be provided to resolve the interlayer noise problem based on the numerical analysis of various boundary conditions. Applied Sciences 2016-04-26 6 5 Article 10.3390/app6050120 120 2076-3417 2016-04-26 doi: 10.3390/app6050120 Sangki Park Haseog Kim http://www.mdpi.com/2076-3417/6/5/121 In this work, the first experimental results of thermotropic liquid crystals used as phase change materials for thermal storage are presented. For that purpose, the n = 10 derivative from the family of 4′-n-alkoxybiphenyl-4-carboxylic acids has been prepared. Different techniques like polarized-light microscopy, differential scanning calorimetry, thermogravimetric analysis and rheological measurements have been applied for its characterization. Having a mesophase/isotropic transition temperature around 251 °C, a clearing enthalpy of 55 kJ/kg, a thermal heat capacity of around 2.4 kJ/kg and a dynamic viscosity lower than 0.6 Pas, this compound fulfills the main requirements for being considered as latent heat storage material. Although further studies on thermal stability are necessary, the results already obtained are both promising and encouraging since they demonstrate de viability of this new application of liquid crystals as thermal storage media. Applied Sciences 2016-04-25 6 5 Article 10.3390/app6050121 121 2076-3417 2016-04-25 doi: 10.3390/app6050121 Rocío Bayón Silverio Coco María Barcenilla Pablo Espinet Gorka Imbuluzqueta Jokin Hidalgo Esther Rojas http://www.mdpi.com/2076-3417/6/5/119 To strengthen concrete beams, a new anchorage was proposed, and its performance was evaluated in this study. Seven concrete beams were manufactured and flexurally loaded with displacement control up to the failure point. As important test variables, the anchorage type (new/conventional) and the prestress levels in the steel rebar (0, 50, and 100 kN) were selected. To investigate the strengthening effects based on these test variables, the deflection, strain, and failure mode were recorded, and then the load, ductility index, and energy ratio were analyzed. Test results showed that the newly proposed end anchorage had better strengthening effects and a greater inelastic energy than the conventional end anchorages. Applied Sciences 2016-04-25 6 5 Article 10.3390/app6050119 119 2076-3417 2016-04-25 doi: 10.3390/app6050119 Sungnam Hong Dooyong Cho Sun-Kyu Park http://www.mdpi.com/2076-3417/6/4/118 Intraguild predation (IGP) is a widespread ecological phenomenon which occurs when one predator species attacks another predator species with which it competes for a shared prey species. The objective of this paper is to study the dynamical properties of a stochastic intraguild predation model. We analyze stochastic persistence and extinction of the stochastic IGP model containing five cases and establish the sufficient criteria for global asymptotic stability of the positive solutions. This study shows that it is possible for the coexistence of three species under the influence of environmental noise, and that the noise may have a positive effect for IGP species. A stationary distribution of the stochastic IGP model is established and it has the ergodic property, suggesting that the time average of population size with the development of time is equal to the stationary distribution in space. Finally, we show that our results may be extended to two well-known biological systems: food chains and exploitative competition. Applied Sciences 2016-04-22 6 4 Article 10.3390/app6040118 118 2076-3417 2016-04-22 doi: 10.3390/app6040118 Zejing Xing Hongtao Cui Jimin Zhang http://www.mdpi.com/2076-3417/6/4/117 High quality headphones can generate a realistic sound immersion reproducing binaural recordings. However, most people commonly use consumer headphones of inferior quality, as the ones provided with smartphones or music players. Factors, such as weak frequency response, distortion and the sensitivity disparity between the left and right transducers could be some of the degrading factors. In this work, we are studying how these factors affect spatial perception. To this purpose, a series or perceptual tests have been carried out with a virtual headphone listening test methodology. The first experiment focuses on the analysis of how the disparity of sensitivity between the two transducers affects the final result. The second test studies the influence of the frequency response relating quality and spatial impression. The third test analyzes the effects of distortion using a Volterra kernels scheme for the simulation of the distortion using convolutions. Finally, the fourth tries to relate the quality of the frequency response with the accuracy on azimuth localization. The conclusions of the experiments are: the disparity between both transducers can affect the localization of the source; the perception of quality and spatial impression has a high correlation; the distortion produced by the range of headphones tested at a fixed level does not affect the perception of binaural sound; and that some frequency bands have an important role in the front-back confusions. Applied Sciences 2016-04-22 6 4 Article 10.3390/app6040117 117 2076-3417 2016-04-22 doi: 10.3390/app6040117 Pablo Gutierrez-Parera Jose Lopez http://www.mdpi.com/2076-3417/6/4/116 Equalisation is one of the most commonly-used tools in sound production, allowing users to control the gains of different frequency components in an audio signal. In this paper we present a model for mapping a set of equalisation parameters to a reduced dimensionality space. The purpose of this approach is to allow a user to interact with the system in an intuitive way through both the reduction of the number of parameters and the elimination of technical knowledge required to creatively equalise the input audio. The proposed model represents 13 equaliser parameters on a two-dimensional plane, which is trained with data extracted from a semantic equalisation plug-in, using the timbral adjectives warm and bright. We also include a parameter weighting stage in order to scale the input parameters to spectral features of the audio signal, making the system adaptive. To maximise the efficacy of the model, we evaluate a variety of dimensionality reduction and regression techniques, assessing the performance of both parameter reconstruction and structural preservation in low-dimensional space. After selecting an appropriate model based on the evaluation criteria, we conclude by subjectively evaluating the system using listening tests. Applied Sciences 2016-04-20 6 4 Article 10.3390/app6040116 116 2076-3417 2016-04-20 doi: 10.3390/app6040116 Spyridon Stasis Ryan Stables Jason Hockman http://www.mdpi.com/2076-3417/6/4/115 In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately maintains the sun's radiation perpendicular to the plane of the heating head. The results indicated that the position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, we can obtain the maximum temperature of the heating head of the Stirling engine. Therefore, the temperature of heating head can be higher than 1000 °C in our experiment on a sunny day. Moreover, the results also revealed that the temperature decrease of the heating head is less than the power decrease of solar irradiation because of the latent heat of copper and the small heat loss from the heating head. Applied Sciences 2016-04-20 6 4 Article 10.3390/app6040115 115 2076-3417 2016-04-20 doi: 10.3390/app6040115 Tsung Cheng Chao Yang I Lin http://www.mdpi.com/2076-3417/6/4/110 This paper summarizes an engineering experience of solving the problem of thermal cracking in mass concrete by using a large project, Zhongguancun No.1 (Beijing, China), as an example. A new method is presented for controlling temperature cracks in the mass concrete of a foundation. The method involves controlled cycles of water circulating between the surface of mass concrete foundation and the atmospheric environment. The temperature gradient between the surface and the core of the mass concrete is controlled at a relatively stable state. Water collected from the well-points used for dewatering and from rainfall is used as the source for circulating water. Mass concrete of a foundation slab is experimentally investigated through field temperature monitoring. Numerical analyses are performed by developing a finite element model of the foundation with and without water circulation. The calculation parameters are proposed based on the experiment, and finite element analysis software MIDAS/CIVIL is used to calculate the 3D temperature field of the mass concrete during the entire process of heat of hydration. The numerical results are in good agreement with the measured results. The proposed method provides an alternative practical basis for preventing thermal cracks in mass concrete. Applied Sciences 2016-04-20 6 4 Article 10.3390/app6040110 110 2076-3417 2016-04-20 doi: 10.3390/app6040110 Wenchao Liu Wanlin Cao Huiqing Yan Tianxiang Ye Wang Jia http://www.mdpi.com/2076-3417/6/4/114 Surface reconstruction for freehand 3D ultrasound is used to provide 3D visualization of a VOI (volume of interest) during image-guided tumor ablation surgery. This is a challenge because the recorded 2D B-scans are not only sparse but also non-parallel. To solve this issue, we established a framework to reconstruct the surface of freehand 3D ultrasound imaging in 2011. The key technique for surface reconstruction in that framework is based on variational interpolation presented by Greg Turk for shape transformation and is named Variational Surface Reconstruction (VSR). The main goal of this paper is to evaluate the quality of surface reconstructions, especially when the input data are extremely sparse point clouds from freehand 3D ultrasound imaging, using four methods: Ball Pivoting, Power Crust, Poisson, and VSR. Four experiments are conducted, and quantitative metrics, such as the Hausdorff distance, are introduced for quantitative assessment. The experiment results show that the performance of the proposed VSR method is the best of the four methods at reconstructing surface from sparse data. The VSR method can produce a close approximation to the original surface from as few as two contours, whereas the other three methods fail to do so. The experiment results also illustrate that the reproducibility of the VSR method is the best of the four methods. Applied Sciences 2016-04-19 6 4 Article 10.3390/app6040114 114 2076-3417 2016-04-19 doi: 10.3390/app6040114 Shuangcheng Deng Yunhua Li Lipei Jiang Ping Liang http://www.mdpi.com/2076-3417/6/4/113 The main goal of osteoporosis treatment is prevention of osteoporosis-induced bone fracture. Dual-energy X-ray absorptiometry (DXA) and quantitative computed tomographic imaging (QCT) are widely used for assessment of bone mineral density (BMD). However, they have limitations in patients with special conditions. This study evaluated a method for diagnosis of osteoporosis using peripheral cone beam computed tomography (CBCT) to estimate BMD. We investigated the correlation between the ratio of cortical and total bone areas of the forearm and femoral neck BMD. Based on the correlation, we established a linear transformation between the ratio and femoral neck BMD. We obtained forearm images using CBCT and femoral neck BMDs using dual-energy X-ray absorptiometry (DXA) for 23 subjects. We first calculated the ratio of the cortical to the total bone area in the forearm from the CBCT images, and investigated the relationship with the femoral neck BMDs obtained from DXA. Based on this relationship, we further investigated the optimal forearm region to provide the highest correlation coefficient. We used the optimized forearm region to establish a linear transformation of the form to estimate femoral neck BMD from the calculated ratio. We observed the correlation factor of r = 0.857 (root mean square error = 0.056435 g/cm2; mean absolute percentage error = 4.5105%) between femoral neck BMD and the ratio of the cortical and total bone areas. The strongest correlation was observed for the average ratios of the mid-shaft regions of the ulna and radius. Our results suggest that femoral neck BMD can be estimated from forearm CBCT images and may be useful for screening osteoporosis, with patients in a convenient sitting position. We believe that peripheral CBCT image-based BMD estimation may have significant preventative value for early osteoporosis treatment and management. Applied Sciences 2016-04-19 6 4 Article 10.3390/app6040113 113 2076-3417 2016-04-19 doi: 10.3390/app6040113 Kwanmoon Jeong Hoon Ko Chang-Hoon Lee Myeung Lee Kwon-Ha Yoon Jinseok Lee http://www.mdpi.com/2076-3417/6/4/111 An innovative high-speed lancing device has a lancet that moves so fast that it is not affected at all by the vibration of its spring, and does not pierce the skin repeatedly, greatly reducing the pain that is caused to diabetes mellitus (DM) patients during blood sampling. As revealed by experimental measurements of the acceleration of a lancet using an accelerometer, the lancet pierces the skin only once. The maximum acceleration and the instant piercing velocity of the lancet are 9.4 times and 1.78 times those of a conventional lancing device, respectively. Meanwhile, the period for which the lancet remains in the skin is 0.014 s shorter than that of the conventional lancing device. A clinical trial that involved 100 participants yielded statistical results concerning the numeric rating of pain scale (NRS) of pain intensity, which is internationally recognized as the pain with the highest validity, that showed that the NRS of participants who used the innovative high-speed lancing device was 2.65 less than that of those who used the conventional lancing device, and the duration of the pain after blood sampling was 76.1 min shorter. Applied Sciences 2016-04-18 6 4 Article 10.3390/app6040111 111 2076-3417 2016-04-18 doi: 10.3390/app6040111 Ho Chang Yao-Jen Yeh Rahnfong Lee Chia-Chun Lee Jenq-Huey Shyu http://www.mdpi.com/2076-3417/6/4/112 The thermal behavior of a commercial paraffin with a melting temperature of 58 °C is analyzed as a phase change material (PCM) candidate for industrial waste heat recovery and domestic hot water applications. A full and complete characterization of this PCM is performed based on two different approaches: a laboratory characterization (mass range of milligrams) and an analysis in a pilot plant (mass range of kilograms). In the laboratory characterization, its thermal and cycling stability, its health hazard as well as its phase change thermal range, enthalpy and specific heat are analyzed using a differential scanning calorimeter, thermogravimetric analysis, thermocycling and infrared spectroscopy. Laboratory analyses showed its suitability up to 80 °C and for 1200 cycles. In the pilot plant analysis, its thermal behavior was analyzed in a shell-and-tube heat exchanger under different heat transfer fluid mass flow rates in terms of temperature, power and energy rates. Results from the pilot plant analysis allowed understanding the different methods of heat transfer in real charging and discharging processes as well as the influence of the geometry of the tank on the energy transferred and required time for charging and discharging processes. Applied Sciences 2016-04-18 6 4 Article 10.3390/app6040112 112 2076-3417 2016-04-18 doi: 10.3390/app6040112 Jaume Gasia Laia Miró Alvaro de Gracia Camila Barreneche Luisa Cabeza http://www.mdpi.com/2076-3417/6/4/109 Double- and triple-walled carbon nanotubes (DWNTs and TWNTs) consist of coaxially-nested two and three single-walled carbon nanotubes (SWNTs). They act as the geometrical bridge between SWNTs and multi-walled carbon nanotubes (MWNTs), providing an ideal model for studying the coupling interactions between different shells in MWNTs. Within this context, this article comprehensively reviews various synthetic routes of DWNTs' and TWNTs' production, such as arc discharge, catalytic chemical vapor deposition and thermal annealing of pea pods (i.e., SWNTs encapsulating fullerenes). Their structural features, as well as promising applications and future perspectives are also discussed. Applied Sciences 2016-04-16 6 4 Review 10.3390/app6040109 109 2076-3417 2016-04-16 doi: 10.3390/app6040109 Kazunori Fujisawa Hee Kim Su Go Hiroyuki Muramatsu Takuya Hayashi Morinobu Endo Thomas Hirschmann Mildred Dresselhaus Yoong Kim Paulo Araujo http://www.mdpi.com/2076-3417/6/4/108 In recent decades, the proliferation of smart phones, tablets, and wireless networks has fostered a growing interest in indoor passive positioning. The Wi-Fi-based passive positioning systems can provide Location-Based Services (LBSs) to the third party such as market and security departments. Most of the existing systems are based on the Receive Signal Strength Indication (RSSI) information, which are generally time-consuming and susceptible to environmental change. To overcome this problem, we propose the Wi-Fi compass for indoor passive positioning system (WIPP), an Angle of Arrival (AOA) based passive positioning system using the existing commodity Wi-Fi network. In this paper, we first propose a new algorithm for the joint estimation of AOA and Time of Arrival (TOA) measurements based on the fine-grained Channel State Information (CSI), which is collected by an off-the-shelf Wi-Fi device equipped with only three antennas. Second, we use the affinity propagation clustering algorithm to identify the direct signal path from the target to each Wi-Fi Access Point (AP). Finally, we deploy the WIPP in an actual indoor environment to conduct the performance comparison with the well-known radio-frequency (RF) based system for locating and tracking users inside buildings (RADAR), as well as the conventional passive positioning system using the AOA solely. The experimental results show that the WIPP is able to achieve the median positioning error 0.7 m, which is much lower than the ones by the RADAR system and the conventional system using the AOA solely. Applied Sciences 2016-04-13 6 4 Article 10.3390/app6040108 108 2076-3417 2016-04-13 doi: 10.3390/app6040108 Zhenyuan Zhang Zengshan Tian Mu Zhou Ze Li Zipeng Wu Yue Jin http://www.mdpi.com/2076-3417/6/4/106 Phase change materials (PCMs) have been used in various fields including the materials of buildings. In this research, mixed shape-stabilized PCMs (Mixed SSPCMs) were prepared by impregnating coconut oil and n-hexadecane into exfoliated graphite nanoplatelets (xGnP) through a vacuum impregnate method. Coconut oil is fatty acid ester PCM which is relatively economical in comparison to other PCMs, and n-hexadecane is paraffin PCM that has high latent heat capacity. Drawbacks include leakage in a liquid state and low thermal conductivity resolved by xGnP. When preparing Mixed SSPCMs, coconut oil and n-hexadecane were impregnated at different proportions, namely 70:30, 50:50, 30:70 wt %. Mixed SSPCMs were analyzed through SEM, FT-IR, DSC, TGA and TCi. As a result, we confirmed the microstructure, chemical stability, thermal properties, thermal stability and thermal conductivity of Mixed SSPCMs. Latent heat capacity of Mixed SSPCMs were 89.06, 104.30 and 124.50 J/g while those of SSPCMs containing single PCM were 82.34 and 96.40 J/g. Thermal conductivity of Mixed SSPCMs was more than 284% higher than that of pure coconut oil and n-hexadecane. Finally, we confirmed that coconut oil and n-hexadecane were impregnated into xGnP, and the Mixed SSPCMs have high thermal durability. Applied Sciences 2016-04-12 6 4 Article 10.3390/app6040106 106 2076-3417 2016-04-12 doi: 10.3390/app6040106 Hwayoung Lee Su-Gwang Jeong Seong Chang Yujin Kang Seunghwan Wi Sumin Kim