Embodiments of the present invention pertain to the formation of microelectronic structures. Low k dielectric materials need to exhibit a dielectric constant of less than about 2.6 for the next technology node of 32 nm. The present invention enables the formation of semiconductor devices which make use of such low k dielectric materials while providing an improved flexural and shear strength integrity of the microelectronic structure as a whole.

1. Field
A number of low k materials which meet the microelectronics industry dielectric constant requirements contain carbon and are deposited by plasma enhanced chemical vapor deposition (PECVD). The carbon containing low k dielectrics need to have a uniform carbon distribution. In addition, the presence of carbon affects the adhesion between a low k dielectric layer and an underlying or overlying diffusion barrier layer.
2. Description of the Background Art
This section describes background subject matter related to the disclosed embodiments of the present invention. There is no intention, either express or implied, that the background art discussed in this section legally constitutes prior art.
The next generation of semiconductor devices will be the 32 nm "technology node". This small feature size requires that each layer of material which forms a part of the device structure be able to perform its function in a smaller space than was previously available. As a result, during the deposition of very thin layers (350 Å or less) of material which make up the device, abrupt changes in material compositions and structures may occur which have undesirable effects, (causing problems in the device function). For example, a layer of low k material is applied for purposes of providing an electrically insulating function, but just enough to control electrical signal transfer while not slowing the functioning of the device as a whole. A number of low k materials have been developed in recent years, and frequently these materials are used in contact with a surface of a diffusion barrier layer which prevents migration of conductive materials into adjacent semiconductor or dielectric layers.
It is important that there be good adhesion between the low k dielectric layer and the diffusion barrier layer. This is important for device performance integrity. It is also important during fabrication of the devices, because the most commonly used processes for creating "multi-layer metal" devices (i.e. multi-layered connectivity devices which are useful in reducing device size) are damascene processes which make use of flattening, milling processes such as chemical mechanical polishing. These milling processes create stress at interfaces between layers present in the device structure at the time of milling.
The stresses created between device layers during a process such as chemical mechanical polishing (CMP) can deform the device, separate interfacial surfaces, and cause performance defects.
Low k dielectric materials which have been developed in recent years and the manner in which these materials are used are described in the related patents and applications previously referred to herein, as well as others mentioned below, for example. This is not an all inclusive list of the background art, but hopefully provides a general understanding of the technology which is improved upon by the present invention.
U.S. Pat. No. 6,455,417 to Bao et al., issued Sep. 24, 2002, titled: "Method for Forming Damascene Structure Employing Bi-layer Carbon doped Silicon Nitride/Carbon Doped Silicon Oxide Etch Stop Layer", describes a damascene method for forming a microelectronic structure, which employs a first etch stop/liner layer formed on a substrate, where the first etch stop/liner layer comprises a carbon doped silicon nitride material and a second layer formed upon the first layer, where the second layer is a carbon doped silicon oxide dielectric material. (Abstract) In a preferred embodiment of the Bao et al. structure, both the carbon doped silicon nitride material and the carbon doped silicon oxide material are formed by employing a PECVD method. Typically the starting precursors used in the PECVD process include an organosilane as a silicon and carbon source material. The organosilane material may be reacted with nitrogen source material such as nitrogen, ammonia, or hydrazine, for example to form the carbon doped silicon nitride. The organosilane material may be reacted with an oxygen source material such as oxygen, ozone, nitrous oxide, nitric oxide, carbon monoxide, and carbon dioxide to form a carbon doped silicon oxide.
Schmitt et al. U.S. Pat. No. 7,611,996 B2 describes the deposition of low k dielectric layers using chemical vapor deposition (CVD), and preferably plasma enhanced CVD (PECVD), so that reactant gases used to produce depositing films can be excited by the plasma and a lower temperature is required for film deposition. A discussion of various CVD deposited films and their function includes the consideration that as devices get smaller, the contribution of resistivity from structures of multiple layered films increases, slowing down the performance of a device. In addition, smaller device geometries result in an increase in parasitic capacitance between devices. Parasitic capacitance between metal interconnects on the same or adjacent layers in a circuit can result in crosstalk between the metal lines or interconnects and/or resistance-capacitance (RC) delay, thereby reducing the response time of the device and degrading the overall performance of the device. The problem becomes worse as the number of levels of metal interconnects is increased.
To reduce the parasitic capacitance between metal interconnects on the same or adjacent layers, it has been necessary to change the low k dielectric material used between the metal lines or interconnects to a material having an increasingly lower dielectric constant. A dielectric constant below 2.5 is mentioned as desirable in the Schmitt et al. patent. The material developed to obtain this dielectric constant was a nano-porous silicon oxide film having dispersed microscopic gas voids. This low k dielectric material is said to be typically deposited over the surface of a barrier layer which is comprised of a PECVD silicon oxide, silicon nitride, silicon oxynitride, or hydrogenated silicon carbide.
The Lee et al. patent (U.S. Pat. No. 7,151,053 B2) describes a method of depositing a barrier layer on a substrate by reacting a gas comprising an oxygen-containing organosilicon compound, a compound comprising oxygen and carbon, and an oxygen-free organosilicon compound, where the resulting film deposited is an oxygen-doped silicon carbide layer having an oxygen content of about 15 atomic % or less. In another embodiment, the reactants include a compound comprising oxygen and carbon and an oxygen-free organosilicon compound, which can also be used to produce an oxygen-doped silicon carbide layer having an oxygen content of about 15 atomic % or less.
The development of silicon oxycarbide films having both a low dielectric constant and desirable chemical and mechanical properties has turned out to be challenging. It has been observed that silicon oxycarbide films which have a desirably low dielectric constant of less than 2.5 often do not adhere well to an underlying barrier layer, such as a silicon and carbon-containing barrier layer. Embodiments of the invention described in the Lakshmanan et al. patent (U.S. Pat. No. 7,189,658 B2) describe a method of depositing a low k dielectric layer, where the low k dielectric layer is deposited in a manner such that there is an oxygen concentration gradient within the deposited layer. The underlying barrier layer may be a silicon carbide, nitrogen-doped silicon carbide, oxygen-doped silicon carbide, or oxygen and nitrogen-doped silicon carbide layer. The low k dielectric layer deposited over the barrier layer is formed using a PECVD process in which the processing gas feed comprises an organosilicon compound and an oxidizing gas, where the flow rate of the organosilicon compound is increased as the deposition progresses. This provides a higher oxygen content and a lower carbon content at the interface between the barrier layer and the low k dielectric layer.
The concept of producing a series of layers to create microelectronic structure having desired properties within a PECVD processing chamber is also described in the Edelstein et al. patent (U.S. Pat. No. 7,615,482). A method is disclosed in which a starting substrate surface is a layer of dielectric or conductive material. A layer of oxide (silicon oxide) is formed on the substrate surface, where the oxide layer contains essentially no carbon. A graded transition layer is then formed over the oxide layer, where the graded transition layer has essentially no carbon at the interface with the oxide layer and gradually increases in carbon content towards a porous SiCOH layer, which forms the upper portion of the low dielectric constant layer. The precursor material used to produce the SiCOH layer is said to be ramped up while the oxygen concentration in the PECVD feed gas is ramped down.
As discussed with reference to FIGS. 2 and 3 of the Edelstein et al. patent, there are likely problems with adhesion between the various layers which have different chemical compositions. For purposes of illustration, please see FIG. 1 of the present application, which illustrates a renumbered Edelstein et al. example for a two metallization layer structure. One of skill in the art will recognize that there may be up to 7 or more metallization layers, depending on the device structure. In FIG. 1A, the semiconductor structure 100 includes a semiconductor material 102 which underlies a low k dielectric layer 104 which contains a metal line 106. Overlying metal line 106 is a capping layer 110, which may be a silicon carbide material such as SiCH or SiCHN, as described in the Edelstein et al. patent. Overlying capping layer 110 is an interfacial structure 112, which is said to be made up of two layers 112a and 112b, as illustrated in more detail in FIG. 1B.
Layer 112a is said to be an oxide layer having essentially no carbon, where "essentially" is defined as ranging from 0.1 to 3 atomic percent carbon. A carbon content of this amount is said not to adversely affect the performance of the oxide layer 112a. Layer 112b is said to be a transition layer, which transitions from an oxide layer having essentially no carbon to a porous SiCOH layer. Overlying the surface of layer 112b is a homogeneous low k dielectric layer of SiCOH which is shown as layer 114. The low k dielectric layer 114 is equivalent to the low k dielectric layer 104. A connective contact via 108 containing a conductive fill material 108 is surrounded by low k dielectric layer 104. A second level metal line 116 is in contact with the conductive material present in connective via 108.
Overlying second metal line 116 is a second capping layer 120, which may be a silicon carbide material such as SiCH or SiCHN, as described in the Edelstein et al. patent. Overlying second capping layer 120 is a second interfacial structure 122, which is made up of two layers (not shown) which would be the equivalent of layers 112a and 112b which are shown in FIG. 1B. A second level contact via 118 filled with conductive material makes the connection with the second metal line 116, and may connect to additional layers of metallization which are not shown above second level via 118. A third homogeneous low k dielectric layer 124 of SiCOH surrounds contact via 118.
As discussed in the Edelstein et al. patent, the problem with the structure shown in prior art FIGS. 1A and 1B (of the present application) is said to be that adhesion tends to be inadequate between the SiCOH layer (104, 114, and 124) and the underlying layer, which may be a semiconductor material 102 (such as silicon, for example) or may be a capping (barrier) material layer (112 and 122) which has typically been a silicon carbide-based material. The transition layer, shown as 112b in prior art FIG. 1B (shown in the present application) is intended to improve the adhesion between layer 112b and underling layer 112a, which is the silicon oxide layer which contains essentially no carbon. Further, layer 112a is said to have been demonstrated to bond well to the surface of the low k dielectric SiCOH layer (104, 114 and 124).
In the Edelstein et al. patent, the key to deposition of the transition layer (shown as 112b in the present application prior art FIG. 1B) is said to be that there is a smooth transition in the amount of carbon present in the depositing film as the amount of carbon is increased. However, finding a method of achieving this smooth transition has been somewhat elusive. For example, the Edelstein et al., patent teaches that the feed of reactive precursors shown in FIG. 5 of the Edelstein et al. patent results in a large carbon peak in the carbon graded transition layer formed, eventually resulting in a mechanically weak interfacial layer with the underlying surface. To solve this problem, a different introduction schedule of the reactants into the chamber, of the kind shown in Edelstein et al. FIG. 6 was used. This was said to still result in a carbon peak and an oxygen dip during film deposition, both of which lead to a mechanically weak interfacial layer at the underlying surface. Finally, a revised introduction schedule of reactants into the chamber, of the kind shown in Edelstein et al. FIG. 7 (prior art FIG. 2 of the present application) is said to provide a transition layer in which both carbon and porosity gradually and uniformly increase.
As mentioned above, prior art FIG. 2 of the present application shows the Edelstein et al FIG. 7. FIG. 200 is a graph showing relative flow rates for various precursor materials on axis 204 and a time period related to the PECVD film deposition process at which the flow is taking place on axis 202. The actual flow rates are not specified in the Edelstein disclosure. The time periods are specified, where T1 is said to range from 1-4 seconds, T2 is said to range from 2-4 seconds, T3 is said to be greater than T2. T4 is described as the time when all flows are stabilized at values to deposit the porous SiCOH low k dielectric film. T4 is said to typically range from 10 seconds to 200 seconds. Curve 206 represents a porogen (one of the kinds known in the art) precursor flow, the precise composition of which is not defined in the Edelstein et al. patent. Curve 208 represents oxygen flow, and Curve 210 represents the SiCOH low k dielectric precursor flow. The low k dielectric precursor materials are not specifically described. T2 is said to be the time at which the dielectric precursor flow is stable. The porogen precursor is said to be introduced during the T1-T2 interval. T3 is said to be the time at which the porogen precursor flow is stable. The ramp up rate of the porogen precursor may be lower than the ramp up rate of the dielectric precursor, as is shown in the present prior art FIG. 2. The interval between T2 and T3 is said to be preferably as short as possible.
Despite all of this effort, the adhesion between barrier layers and low k dielectric layers has continued to cause problems with respect to the structural stability of the overall multi metal layer structures which include low k dielectric layers. The present invention provides an improvement over the prior art described above, by providing an improved device structure which inherently solves many of the prior art problems. While the present invention makes use of many of the same precursor materials as those described in the art, the manner in which the materials are applied is different, and this provides the improved device structure.

Microelectronic structure including a low k dielectric and a method of controlling carbon distribution in the structure


A two-axis inclinometer having an inclination-sensitive ray-deflecting device is described, via which a geometrical figure having at least one angle is projected onto a linear array. In addition to providing high resolution, a large measurement range is also opened up by the special arrangement and configuration of the geometrical figure. X-, Y- and overlapping inclinations can be determined simultaneously using the described inclinometer.

The invention relates to a two-axis inclinometer for measuring inclinations or changes in inclination in two mutually perpendicular directions.
Two-axis inclinometers are used, for example, in geodesy for leveling geodetic measuring instruments. In such inclinometers, an element is provided which changes its position as a function of gravity. A measuring mark is projected above the element onto a positionally stable receiver. A positional variation arising here with respect to a previously adjusted zero point is a measure of the inclination of the instrument.
Such an inclinometer is known from EP 0 161 207 B1. Using slit illumination, a light bundle is projected via a mirror onto a combined glass-liquid prism. The prism has a container filled with silicone oil, the inclination being determined via a reflection at the liquid horizon and projection of the ray onto a light-sensitive array. It is possible to determine only a uniaxial direction of inclination in conjunction with a restricted measurement range using the slit illumination described in the above reference. However, biaxial inclination measurements are necessary with geodetic instruments, in particular.


Some of the embodiments provide a queue comprising a plurality of memory cells arranged in a first column and a second column, the plurality of memory cells also arranged in a plurality of levels, such that ones of the levels include a corresponding memory cell of the first column and a corresponding memory cell of the second column, such that a memory cell of the first column is coupled to at least (i) another memory cell of the first column that is at a different level than a level of the memory cell of the first column and (ii) another memory cell of the second column that is at a same or a different level than the level of the memory cell of the first column; and a control module to selectively add data, selectively remove data, and selectively transfer data between the memory cells of the queue.

Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in the present disclosure and are not admitted to be prior art by inclusion in this section.
A queue, which queues data packets, can be configured to operate, for example, as a first-in first-out (FIFO) queue, or as a last-in first-out (LIFO) queue. In a FIFO queue, data packets that entered the queue first leave the queue first, i.e., the data packets leave the queue in an order in which the data packets arrived at the queue. On the other hand, in a LIFO queue, data packets that entered the queue last leave the queue first, i.e., the data packets leave the queue in an order that is opposite to an order in which the data packets arrived at the queue.


A can stacking and organization device is present herein. The device includes at least one body segment which is formed of an outer wall, an intermediate wall and an inner wall. A first trough is defined between the outer wall and the intermediate wall, and a second trough is defined between the intermediate wall and the inner wall. The intermediate wall includes at least one indentation formed upon a top surface thereof, such that material collected within the first trough can overflow through the indentation and into the second trough.

Cans, buckets and other containers, including but in no way limited to paint cans, soup cans, oil cans/containers, etc. often need to be organized, stacked, and labeled. This can be true for manufacturers or retailers (e.g., stores and other locations where a large amount of cans may be stored for sale or distribution), as well as consumers (e.g., home owners) or professionals (e.g., painters or other service providers). Furthermore, particularly in the case of paint cans, but also for cans or other containers that hold other products or materials, the paint or other material may drip or spill down the side of the can or container. Without any retention mechanism or feature, the paint or other material will often drip down to the floor or other surface, potentially damaging or destroying that surface.
Accordingly, there is a need in the art for a storage and organization device that can be used to store, retain and organize one or a plurality of cans, including but not limited to paint cans. It would also be beneficial if the device included a feature or function that would catch or retain any paint or other material that may drip down the side of the can or other container. In this manner, it would be advantageous for a retention channel or retention trough to be formed in the device, itself, that would catch and retain dripping paint or other product, thereby preventing the product from reaching and potentially damaging the floor or other supporting surface upon which the can or other container is disposed.

Stacking and organization device for cans and other containers


Methods and compounds effective in ameliorating conditions characterized by unwanted calcium channel activity, particularly unwanted T-type calcium channel activity are disclosed. Specifically, a series of compounds containing N-piperidinyl acetamide derivatives as shown in formula (1).

The entry of calcium into cells through voltage-gated calcium channels mediates a wide variety of cellular and physiological responses, including excitation-contraction coupling, hormone secretion and gene expression (Miller, R. J., Science (1987) 235:46-52; Augustine, G. J. et al., Annu Rev Neurosci (1987) 10: 633-693). In neurons, calcium channels directly affect membrane potential and contribute to electrical properties such as excitability, repetitive firing patterns and pacemaker activity. Calcium entry further affects neuronal functions by directly regulating calcium-dependent ion channels and modulating the activity of calcium-dependent enzymes such as protein kinase C and calmodulin-dependent protein kinase II. An increase in calcium concentration at the presynaptic nerve terminal triggers the release of neurotransmitter, which also affects neurite outgrowth and growth cone migration in developing neurons.
Calcium channels mediate a variety of normal physiological functions, and are also implicated in a number of human disorders. Examples of calcium-mediated human disorders include but are not limited to congenital migraine, cerebellar ataxia, angina, epilepsy, hypertension, ischemia, and some arrhythmias. The clinical treatment of some of these disorders has been aided by the development of therapeutic calcium channel antagonists (e.g., dihydropyridines, phenylalkyl amines, and benzothiazapines all target L-type calcium channels) (Janis, R. J. & Triggle, D. J., Ion Calcium Channels: Their Properties, Functions, Regulation and Clinical Relevance (1991) CRC Press, London).
Native calcium channels have been classified by their electrophysiological and pharmacological properties into T-, L-, N-, P/Q- and R-types (reviewed in Catterall, W., Annu Rev Cell Dev Biol (2000) 16: 521-555; Huguenard, J. R., Annu Rev Physiol (1996) 58: 329-348). T-type (or low voltage-activated) channels describe a broad class of molecules that transiently activate at negative potentials and are highly sensitive to changes in resting potential.
The L-, N- and P/Q-type channels activate at more positive potentials (high voltage-activated) and display diverse kinetics and voltage-dependent properties (Catterall (2000); Huguenard (1996)). T-type channels can be distinguished by having a more negative range of activation and inactivation, rapid inactivation, slow deactivation, and smaller single-channel conductances. There are three subtypes of T-type calcium channels that have been molecularly, pharmacologically, and elecrophysiologically identified: these subtypes have been termed α1G, α1H, and α1I (alternately called Cav 3.1, Cav 3.2 and Cav 3.3 respectively).
T-type calcium channels are involved in various medical conditions. In mice lacking the gene expressing the α1G subunit, resistance to absence seizures was observed (Kim, C. et al., Mol Cell Neurosci (2001) 18(2): 235-245). Other studies have also implicated the α1H subunit in the development of epilepsy (Su, H. et al., J Neurosci (2002) 22: 3645-3655). There is strong evidence that some existing anticonvulsant drugs, such as ethosuximide, function through the blockade of T-type channels (Gomora, J. C., et al., Mol Pharmacol (2001) 60: 1121-1132).
Low voltage-activated calcium channels are highly expressed in tissues of the cardiovascular system. Mibefradil, a calcium channel blocker 10-30 fold selective for T-type over L-type channels, was approved for use in hypertension and angina. It was withdrawn from the market shortly after launch due to interactions with other drugs (Heady, T. N., et al., Jpn J. Pharmacol. (2001) 85:339-350).
There is also a growing body of evidence that suggests that T-type calcium channels are abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type calcium channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel is minimal. Therefore, selectively blocking calcium channel entry into cancerous cells may be a valuable approach for preventing tumor growth (PCT Patent Application Nos. WO 05/086971 and WO 05/77082; Taylor, J. T., et al., World J. Gastroenterol (2008) 14(32): 4984-4991; Heo, J. H., et al., Biorganic & Medicinal Chemistry Letters (2008) 18:3899-3901).
Growing evidence suggests T-type calcium channels are also involved in pain (see for example: US Patent Application No. 2003/086980; PCT Patent Application Nos. WO 03/007953 and WO 04/000311). Both mibefradil and ethosuximide have shown anti-hyperalgesic activity in the spinal nerve ligation model of neuropathic pain in rats (Dogrul, A., et al., Pain (2003) 105:159-168). In addition to cardiovascular disease, epilepsy (see also US Patent Application No. 2006/025397), cancer and chronic and acute pain, T-type calcium channels have been implicated in diabetes (US Patent Application No. 2003/125269), sleep disorders (US Patent Application No. 2006/003985), Parkinson's disease (US Patent Application No. 2003/087799); psychosis such as schizophrenia (US Patent Application No. 2003/087799), overactive bladder (Sui, G.-P., et al., British Journal of Urology International (2007) 99(2): 436-441; see also US 2004/197825), renal disease (Hayashi, K., et al., Journal of Pharmacological Sciences (2005) 99: 221-227), neuroprotection and male birth control.
All patents, patent applications and publications are herein incorporated by reference in their entirety.

This patent is subject to a terminal disclaimer.

N-piperidinyl acetamide derivatives as calcium channel blockers


Disclosed is a portable molding apparatus for constructing pre-cast structure. The portable molding apparatus comprises a container, a plurality of partition members, at least one retainer, and a plurality of spacing members. The container comprises a floor, and a pair of longitudinal walls vertically extending from the floor for configuring an interior space therebetween. The plurality of partition members is supported on the floor in a spaced apart manner. The at least one retainer is positioned between at least one pair of partition members of the plurality of partition members for configuring at least two sets of partition members. The plurality of spacing members is positioned between partition members of each of the at least two sets of partition members for configuring a plurality of mold cavities therebetween. The plurality of mold cavities is adapted to receive a building material for constructing the pre-cast structures.

With growing population throughout the world, there has been a corresponding steady increase in the number of architectural structures, such as residential buildings, commercial buildings, and bridges. Building of such architectural structures generally involves utilization of pre-cast structures, such as roof panels, wall panels, bridge sections, box culverts, underground supports, stair systems, concrete retainer walls, fencing, beams, and columns Typically, such pre-cast structures are manufactured in industries using conventional concrete molding apparatuses.
More often, it has been observed that such industries are located at a remote place, far from a construction site of the architectural structures. Accordingly, the pre-cast structures, produced in the remote industries, need to be transported to the construction site. The pre-cast structures may be transported to the construction site by using various transportation means, such as road, rail and water transportation. The transportation of the pre-cast structures to the construction site may increase the overall cost involved in the building of the architectural structure. Further, the transported pre-cast structures need to be stored in a proper manner for the further use thereof. More specifically, extra storage space and extra labor for handling the transported pre-cast structures may be required, which may further increase the overall cost involved in the building of the architectural structures.
Moreover, the conventional concrete molding apparatuses used in the industry, does not include a standard size that may enable in easy transportation thereof. Specifically, the conventional concrete molding apparatuses are configured to assume bulky configurations. Therefore, transportation of such conventional concrete molding apparatuses to the construction site may be a difficult task.
Accordingly, there exists a need for a portable molding apparatus for constructing pre-cast structures in the vicinity of a construction site of an architectural structure.

Portable molding apparatus for constructing pre-cast structures


An image combining viewer transmits a daylight image directly through the viewer, while reflecting at least one wavelength other than visible light towards a sensor. A display for displaying the image received by the sensor in a visible wavelength is reflected by the back surface of the mirror back along the optical path, combining the displayed image with the daylight image so that they appear to be a single image.

1. Field of the Invention
The present invention relates to viewers using wavelengths outside the visible spectrum. More specifically, the invention provides a viewer that combines an image transmitted using wavelengths outside the visible spectrum, for example, thermal infrared, with a visible light image.
2. Description of the Related Art
Although other devices for combining visible light images with images formed in other wavelengths have been proposed, there remains a need for such device that minimizes parallax and image shift to a degree to be sufficient for use as a firearms sight, or for use in front of a daytime telescopic sight.
U.S. Patent Application Publication Number US 2003/0206338 A1, disclosing an invention by L. G. Cook and published on Nov. 6, 2003, discloses an optical system for simultaneous imaging of long wave infrared and millimeter wave radiation. The system includes a primary mirror, a Mangin secondary mirror structured to receive light reflected from the primary mirror, and an immersion lens structured to focus the energy received from the secondary mirror. The immersion lens effectively decreases the wavelength of the millimeter wave radiation, allowing a smaller detector to collect the same amount of radiation as would a larger detector in air.
U.S. Pat. No. 6,909,539, issued to R. J. Korniski, et al. on Jun. 21, 2005, discloses a system for combining multiple energy bands to improve scene viewing. The device includes an objective lens that is optimized for both visible/near infrared wavelengths and infrared wavelengths. After passing through the objective lens, visible light is directed towards an image intensifier, while infrared light is transmitted to an IRFPA. The electronic digital image resulting from the infrared image is displayed on a display to a beam combiner to which the intensified image is also displayed. The combined image is displayed to a user's eye. The preferred embodiments are a monocular or binoculars. The patent does not disclose any means for resisting image shift due to expansion and contraction of the various components due to temperature change, or due to the night vision device receiving an impact, a necessary feature for any night vision device used in conjunction with a weapon. A similar device is disclosed in U.S. Pat. No. 6,646,799, issued to the same inventors on Nov. 11, 2003.
U.S. Pat. No. 6,094,302, issued to D. Bergstedt on Jul. 25, 2000, discloses an infrared viewing device having a parallel channel for visible light. The infrared image and visible light image are displayed to the user separately.
U.S. Pat. No. 6,020,994, issued to L. G. Cook on Feb. 1, 2000, discloses a multi-functional viewer providing for infrared viewing, direct visible viewing, CCD based visible TV viewing, and laser range finding. Mode switching mirrors are used to direct the desired image to a single eye piece. No means for combining images is disclosed.
U.S. Pat. No. 5,973,315, issued to M. R. Saldana et al. on Oct. 26, 1999, discloses a day/night observation, ranging and sighting device. Light passing through the objective lens passes through a beam splitter that permits red and orange light to pass through the beam splitter to an image intensifier, and reflects other visible light to a series of lens elements. About 70% to 80% of the light admitted through the objective lens is directed away from the image intensifier. The visible light image and intensified image are combined using a beam combiner, before passing through an aiming reticle and other lens elements towards the eye piece. A laser range finder is also included. A similar device is disclosed in U.S. Pat. No. 5,892,617, issued to R. E. Wallace on Apr. 6, 1999. Neither of these patents discloses any means for resisting image shift due to expansion and contraction of the various components due to temperature changes, or to impact on a device.
U.S. Pat. No. 5,933,277, issued to J. R. Truxell et al. on Aug. 3, 1999, discloses an imaging system combining visible and non-visible electromagnetic radiation for enhanced vision. Electromagnetic radiation entering the imaging system is directed towards a diffraction grating, which reflects the different wavelengths at different angles to the appropriate detectors. The electric signal output from the detectors is transmitted to processing electronics which combine the data from the two scanned signals to produce an enhanced visible image. This patent does not disclose an image combining method having sufficient resolution for use with firearm sights.
U.S. Pat. No. 5,781,336, issued to B. Coon et al. on Jul. 14, 1998, discloses the use of the combination of a magnesium oxide lens and a calcium fluoride lens for multi-spectral imaging systems utilizing both the visible and infrared spectrums.
U.S. Pat. No. 5,157,548, issued to L. Monnier et al. on Oct. 20, 1992, discloses an optical device combining either a direct daylight view or an intensified image with an image generated by an image generator. No method of combining visible light image with an image outside the visible spectrum is disclosed.
U.S. Pat. No. 5,035,472, issued to C. L. Hansen on Jul. 30, 1991, discloses an integrated multi-spectral man portable weapon sight. The sight emits visible, near infrared, and far infrared light through a single objective lens using beam splitters to separate the light into near infrared, far infrared, and visible light. No means of combining visible light image with an image formed in another wavelength is disclosed.
U.S. Pat. No. 5,841,574, issued to G. W. Willey on Nov. 24, 1998, discloses a multi-spectral decentered catadioptric optical system. The entrance pupil of the lens is not concentric with the lens. The small residual obscuration enters the circular pupil from one side, instead of being located in the center.
Accordingly, there is a need for a system of combining a visible light image with an image from a different wavelength, having sufficient resolution and elimination of parallax for use in conjunction with a firearm sight. There is a further need for such a device that may be placed in front of a firearm sight, without changing the relationship between point of aim and the point of impact of the firearm sight.


The present invention provides a wet-processing apparatus comprising a chamber having a working space, means for wet processing in the working space, means for supplying nitrogen gas in fluid communication with the chamber, a nitrogen gas outlet located in a wall of the chamber, means for cleaning nitrogen gas by removing contaminants mixed therewith located in an area of the chamber downstream of the working space and upstream of the nitrogen gas outlet and having a contaminated gas inlet and a treated gas outlet in fluid communication with the chamber, means for diverting gas in the chamber located downstream of the treated gas outlet and upstream of the nitrogen gas supplying means, the means for diverting gas having a first position providing egress of treated gas from the chamber through the nitrogen gas outlet while inhibiting fluid communication to other parts of the chamber and a second position permitting fluid communication and recirculation of the treated gas to other parts of the chamber while preventing egress of the treated gas through the nitrogen gas outlet, and means for circulating nitrogen gas in the chamber.

1. Field of the Invention
This invention relates to a wet-process apparatus and a control method for the same and, in particular, to a wet-process apparatus which is equipped with a function of quickly creating a highly clean space as needed when using chemicals in a clean room, and to a control method for such an apparatus.
2. Description of the Related Art
FIG. 4 is a schematic sectional view of a conventional wet-process apparatus. In the drawing, a wet-process apparatus 1 includes a chamber 2 isolated from the atmospheric air. Provided in the upper section of the chamber 2 is a nitrogen-gas supply pipe 3 for supplying nitrogen gas 4 into the wet-process apparatus 1. The nitrogen gas 4 introduced into the wet-process apparatus 1 through the nitrogen-gas supply pipe 3 is fed to a fine cleaning filter 6 by means of a nitrogen-gas supply fan 5 to become highly clean nitrogen gas 7, which is introduced into a working space 9 separated from atmospheric air by an opening/closing means 8, such as a window or a door that can be opened and closed.
Arranged in the working space 9 is a chemical vessel 11 containing a chemical 10, and, lodged in the chemical vessel 11 are a plurality of semiconductor wafers 13 held by a cassette 12, which can be immersed in and taken out of the chemical vessel 11, and further, transferred to other places, by means of an automatic transfer handle 14. The chemical vessel 11 is supported by a draining board 15 having a large number of holes to allow waste liquid 16 of the chemical 10 to drop therethrough. The waste liquid 16 is discharged through a drain port 17 provided at the bottom of the apparatus.
When the highly clean nitrogen gas 7 is contaminated with mist of the chemical 10, it becomes contaminated nitrogen gas 18, which is discharged to the outside through a gas outlet 19.
An example of such a wet-process clean apparatus for creating a highly clean space as needed when using chemicals in a clean room, is disclosed, for example, in Japanese Patent Laid-Open No. 2-211216.
In the conventional wet-process apparatus 1, constructed as described above, the nitrogen gas 4 supplied through the nitrogen-gas supply pipe 3 is conveyed to the fine cleaning filter 6 by the nitrogen-gas supply fan 5, supplying the working space 9 with highly clean nitrogen gas 7. In the working space 9, the highly clean nitrogen gas 7 flows downwards from above, creating a highly clean nitrogen-gas atmosphere in the space. Further, in this space, the automatic transfer handle 4 carries out the operations of immersing or extracting the cassette 12, containing semiconductor wafers 13, in or out of the chemical 10 and transferring it to some other place.
Insofar as they are transferred through the nitrogen-gas atmosphere, the semiconductor wafers 13 which have been processed with the chemical 10 are free from the formation of a natural oxide film thereon; however, if transferred through air which contains oxygen and water, the wafers cannot avoid the formation of a natural oxide film thereon, adversely affecting the characteristics of the semiconductor devices to be made of these wafers. Accordingly, it is desirable that the wet-process operation be performed in a highly clean nitrogen-gas atmosphere.
On the downstream side of the working space 9, the highly clean nitrogen gas 7 is contaminated with mist of the chemical 10, and is discharged through the gas outlet 19 to the exterior of the system as contaminated nitrogen gas 18. Further, that portion of the chemical 10 which has flowed downwards through the draining board 15, accumulates in the lower section of the wet-process apparatus as waste liquid 16, which is discharged through the drain port 17 to the exterior of the system.
A problem with the conventional wet-process apparatus 1, described above, is that all the nitrogen gas 3 supplied thereto is discharged to the exterior of the system, which means a large quantity of nitrogen gas is required to maintain a nitrogen-gas atmosphere in the working space 9 for a long period of time, resulting in an enormous running cost for the apparatus.


Needlepoint sheet having channel perforations with octagonal upper and lower openings. Thread drawn through a channel in a diagonal direction is pulled over a flat surface which widens the area covered by the thread. The needlepoint sheet is made of a polymeric material. The perforations are preferably formed into a plurality of aligned rows for receiving the thread. Each channel is enclosed by eight sides which form octagonal upper and lower openings. The width of each of the sides is substantially equal. In a preferred embodiment of the invention each of the sides form a plane, and the height of each of the side planes is substantially equal. In a preferred embodiment of the invention each of the side planes merge along a curved portion of the wall. This distributes the stress during bending of the needlepoint sheet, and reduces cracking and breakage thereof. In use thread is extended through the channels. At least two of the diagonal sides of each channel are normal to the diagonally positioned portion of the thread. The normal side over which the thread is drawn widens and thus maximize the coverage of the diagonally positioned portions of the thread supported thereby.

The invention relates to a needlepoint sheet of flexible plastic material. In particular the improved needlepoint sheet provides a plurality of eight sided perforations therein for receiving thread-like material therethrough. In a preferred embodiment of the invention each of the sides forms a plane. The height and width of each of the side planes is substantially equal. The improvements of the invention each taken alone or in combination add to resolve the problems of the prior art. The prior art does not provide a needlepoint sheet of flexible plastic material having a plurality of eight sided perforations therein for receiving thread-like material therethrough.
Marx et al. in U.S. Pat. No. 4,404,750 disclose a needlepoint sheet having four sided perforations enclosed on four sides. Kaye in U.S. Pat. No. 4,284,021 discloses a fabric having triangular shaped pores for embroidery. Mabry in U.S. Pat. No. Re. 31,240 discloses a needlework technique using ribbon in a needlework canvas having four sided openings. Martin in U.S. Pat. No. 4,555,429 discloses a curved needlepoint canvas having four sided perforations. Ciganko in U.S. Pat. No. 4,372,238 discloses a toy stitching set having a stitching grid with four sided perforations. Strasburger in U.S. Pat. No. 1,333,687 discloses an oramental mesh having four sided openings.
It is an object of the invention to provide a needlepoint sheet of flexible plastic material having a plurality of channels each enclosed by a channel wall having eight sides wherein the channels are adapted to receive thread-like material therethrough.
It is an object of the invention to provide a needlepoint sheet of flexible plastic material having a plurality of channels each enclosed by a channel wall having eight sides which form octagonal openings at both the upper and lower end portions of each channel and wherein the channels are adapted to receive thread-like material therethrough.
It is an object of the invention to provide a needlepoint sheet of flexible plastic material having a plurality of channels each enclosed by a channel wall having eight planar sides and wherein each planar side is connected to two curved portions of the channel wall and wherein the channels are adapted to receive thread-like material therethrough.
It is an object of the invention to provide a needlepoint sheet having first, second and third channels formed therein, wherein each channel is enclosed by eight sides forming an octagonal upper opening enclosed by eight substantially straight edges of the eight sides.
It is an object of the invention to provide a needlepoint sheet having first, second and third channels formed therein, wherein each channel is enclosed by eight sides forming an octagonal upper opening enclosed by eight substantially straight edges of the eight sides, and wherein the first and second channels are positioned along a first line, the first and third channels being positioned along a second line, and wherein the first and second lines intersect at an acute angle.
One problem of the prior art is that the needlepoint sheets have four sided perforations having rectangular upper and lower openings. Prior art needlepoint sheets do not provide flat surfaces over which to draw thread in both diagonal and orthogonal directions. Needlepoint sheets having octagonal upper and lower openings provide a flat surface over which to draw thread in diagonal and orthogonal directions. Thread drawn over a flat surface flattens the thread and widens the area covered thereby. Another problem of the prior art is that the orthogonal sides of the perforations tend to crack at the corners, i.e. the intersection of the adjacent sides. The improvements of the present invention beneficially provide a novel, nonobvious and useful manner of providing needlepoint sheets which are adapted to provide a flat surface over which to draw thread in diagonal and orthogonal directions.

Needlepoint sheet having octagonal openings and method of use thereof


A new Lantana plant named ‘LANZ0003’ particularly distinguished by the large sized, two-toned yellow flowers, with good floriferousness as a result of limited seed set, and a relatively compact habit with medium green foliage.

The present invention comprises a new Lantana, botanically known as Lantana camara L., and hereinafter referred to by the variety name 'LANZ0003'.
'LANZ0003' is a product of a planned breeding program. The new cultivar has large sized, two-toned yellow flowers, with good floriferousness as a result of limited seed set, and a relatively compact habit with medium green foliage.
'LANZ0003' originates from a hybridization made in July 2007 in a controlled breeding program in Gilroy, Calif., USA. The female parent was unpatented, proprietary plant identified as 'G307-1' with a peach color, a larger flower size, more floriferousness and is about four days later to flower.
The male parent of 'LANZ0003' was identified as 'G292-1', an unpatented, proprietary plant with peach color, larger flowers, and a tighter compact habit. The resultant seed was sown in December 2007.
'LANZ0003' was selected as one flowering plant within the progeny of the stated cross in April 2008 in a controlled environment in Gilroy, Calif.
The first act of asexual reproduction of 'LANZ0003' was accomplished when vegetative cuttings were propagated from the initial selection in December 2008 in a controlled environment in Gilroy, Calif.


A peristaltic pumping mechanism is provided with a non-permeable peristaltic circuit comprising two strips of thin metal laser bonded at their edges to form a tube. In one embodiment, the non-permeable tubing takes the form of a continuous loop having input and output ports. In another embodiment, the tubing is open and generally U-shaped. In still another embodiment, a dual-tube circuit is provided, wherein a central, metal tube is disposed within an outer elastomeric tube having an inner diameter larger than the outer dimension of the metal tube. The elastomeric tube supports the metal tube only at the ends of the circuit, enabling the metal tube to "float" within the elastomeric tube.

In the medical field, there are numerous applications for pumping mechanisms, that generally operate to pump liquid and/or compressible gas mixtures by repeatedly squeezing a flexible tube to push the pumped substance therethrough. Two examples of such pumping mechanisms are "roller pump" peristaltic pumps and linear peristaltic pumps.
Typically, "roller pumps" employ a stator having a bearing surface against which one or more hoses is compressed by a rotating rotor, the rotor engaging the hoses with two or more rollers. On rotation of the rotor, the fluid in the hose or hoses is transported in the direction of the rotor's rotation. Alternatively, the fluid can be presented to the pump under pressure, such that rotation of the rotor causes the pump to serve as a measuring valve. In either instance, knowledge as to the inner diameter of the hose or hoses and the rotational speed of the rotor provides a knowledge of the amount of fluid passed through the hose or hoses, which amount can be regulated by regulating the speed of the rotor.
Examples of prior art "roller pump" peristaltic pumps, used for drug administration devices, are proposed in U.S. Pat. No. 4,576,556 to Thompson, entitled "Roller Pump," and in U.S. Pat. No. 4,692,147 to Duggan, entitled "Drug Administration Device." The Thompson '556 and Duggan '147 patents are commonly assigned to the assignee of the present invention and are hereby incorporated by reference herein in their respective entireties. It has been demonstrated that peristaltic pumps such as those described in the Thompson '556 and Duggan '147 patents provide a highly reliable mechanism for inclusion in a totally body-implantable drug infusion pump including a control system, power source, fluid reservoir, and refilling mechanism.
Linear peristaltic pumps typically have a series of fingers or cams that contact and compress a flexible tube in a sequential linear fashion so that fluid in the tube is pushed along ahead of the closing fingers or cams. Examples of linear peristaltic pumps include U.S. Pat. No. 4,482,347 for "Peristaltic Fluid-Pumping Apparatus" issued to Alexander S. Borsanyi on Nov. 13, 1984, U.S. Pat. No. 4,909,710 for "Linear Peristaltic Pump" issued to David E. Kaplan, David Burkett and Laurence Warden on Mar. 20, 1990 and U.S. Pat. No. 5,217,355 for "Two-Cycle Peristaltic Pump with Occlusion Detector" issued to Oscar E. Hyman, Ahmadmahir M. Moubayd and Larry L. Wilson on Jun. 8, 1993
A desirable characteristic of either type of peristaltic pump is the fact that the substance being pumped does not come into contact with any component of the pump other than the inside of the flexible tubing; thus, sterility of the substance is preserved. Peristaltic pumps are also known to be volumetrically accurate and to have a high degree of constancy and uniformity of flow. In addition, the positive displacement nature of peristaltic pumping mechanisms render them capable of pumping fluid/compressible gas mixtures and fluids with varying viscosities. Peristaltic pumps have proven to be highly reliable for application with, among others, aqueous drug formulations.
Prior art peristaltic pumping mechanisms for drug delivery or infusion typically use an elastomeric tubing circuit as the conduit for moving the drug through the pumping circuit by displacement during tubing compression by peristaltic pumping rollers. Potential disadvantages of prior art designs using elastomeric tubing include the inability to prevent permeation of water vapor and drug components from the drug formulation through the tubing wall, potentially resulting in adverse corrosive effects on the pump motor and gear drive train assembly.
Permeation of water vapor and drug components through the peristaltic tubing wall can also lead to reduced product longevity due to the increased mechanical friction or compromised electrical isolation with increased parasitic electrical resistance in excess of motor output capacity. Moreover, certain drug formulations may require the use of lipophilic agents or organic solvents due to low aqueous solubility. Such agents or solvents may not be compatible with the elastomeric peristaltic tubing, and elastomer degradation or swelling may arise, causing compromised product life.
Parasitic mechanical friction produced by passing the roller over a drug-swollen elastomeric surface creates an additional energy requirement, which can further limit the pump's functional longevity.
In the context of a fully implantable device, exemplified by the SynchroMed.RTM. drug infusion system commercially available from Medtronic, Inc., Minneapolis, Minn., the foregoing and other considerations are of particular concern. If the elastomeric pump circuit does not establish a hermetic barrier to water vapor permeation, the reduction gear drive mechanism, motor coil, and electronic circuitry will be exposed to a humidified environment. With prolonged exposure to such a humidified environment, gear lubricant breakdown can occur, leading to increased gear wear and friction to moving parts. Secondarily, certain elastomeric tubing, such as silicone polymers and the like, are prone to absorption of various components of the therapeutic formations being pumped. This absorption results in elastomeric swell which manifests itself in either reduced life due to friction or immediate pump stall due to frictional forces in excess of pump driving force.


The oscillating velocity of an oscillating body in a fluid to be measured is positively fed back, so as to activate an actuator. The oscillating state of the oscillating body is monitored while making a velocity feedback gain increase. The velocity feedback gain when the oscillating body has oscillated is obtained as an oscillation limit gain at the oscillation limit, and this oscillation limit gain is used as a viscosity equivalent value representing viscosity of the measured fluid.

Viscometers for measuring viscosity of a fluid are generally classified according to basic principles into a capillary viscometer, a falling sphere viscometer, a rotational viscometer, a chemical viscometer, and an oscillating viscometer.
Of these types of viscometers, in JP 2004-361300 A, for example, there is proposed a oscillating viscometer for calculating viscosity of a measured object based on a driving current generated due to an inductor plate being electromagnetically oscillating with a predetermined amplitude, or there is proposed a oscillating viscometer for calculating viscosity of the same by making an oscillating body externally excite, obtaining a frequency response curve representing relationship between excitation frequency and corresponding response amplitude of the oscillating body, and finding a Q value thereof.

Viscosity measuring device and viscosity measuring method

National Institute of Advanced Industrial Science and Technology


Provided herein is a system and method implemented on a vehicle. The system comprises one or more sensors, one or more processors, and a memory storing instructions that, when executed by the one or more processors, causes the system to perform: obtaining data from the one or more sensors; comparing the obtained data from the one or more sensors with reference data; determining whether one or more characteristics of the obtained data deviate from corresponding characteristics of the reference data by more than a respective threshold; in response to determining that one or more characteristics of the data obtained deviate from corresponding characteristics of the reference data by more than a respective threshold, determining an action of the vehicle based on amounts of the one or more deviations; and performing the determined action.

On-board sensors in vehicles, such as autonomous vehicles (AVs), supplement and bolster the vehicle's field of vision by providing accurate sensor data. Sensor data is used, for example, in applications of blind spot detection, lane change assisting, rear end radar for collision warning or collision avoidance, park assisting, cross-traffic monitoring, brake assisting, emergency braking, active suspension controlling, and/or automatic distance controlling. Examples of on-board sensors include, for example, passive sensors and active sensors. On-board sensors include camera, Lidar, radar, GPS, sonar, ultrasonic, IMU (inertial measurement unit), accelerometers, gyroscopes, magnetometers, and FIR (far infrared) sensors. However, current vehicles do not monitor conditions or situations surrounding the vehicle when the vehicle is turned off, thus leaving the vehicle vulnerable. Additionally, current vehicles may not monitor all types of conditions or situations while the vehicle is driving. For example, a sensor on a vehicle may not be configured to detect a potential crime or fire, and the vehicle may not take any action even if a potential crime or fire is nearby. These shortfalls are addressed by the present disclosures, which provide an efficient and effective system and method of continuously monitoring for surrounding conditions or situations near a vehicle even when the vehicle is turned off.


A chaotic receiver estimation engine and method of use. The estimation engine synchronizes and recovers data and performs its decision and tracking processes by mapping probability calculation results onto chaotic dynamics via a strange attractor geometrical approximation. Restrictive standard chaotic synchronization requirements of either a stable/unstable subspace separation or a chaotic system inversion are not required. The receiver determines and models both the logical zero and logical one versions of the strange attractor and the transmitted chaotic sequence probability density function (PDF). Two estimates of the transmitted value are created from each received iterate by probability and the transmitted PDF calculations. A third estimate is generated from the chaotic processing of the previous receiver final decisions. The three estimates are combined using a probability-based weighted average to form the initial current decision. A final current decision incorporates chaotic dynamics by mapping the initial decision onto the geometrical model of the attractors via a minimum Euclidean distance metric.

The present invention relates generally to chaotic communications systems and more particularly to a chaotic communication system utilizing a chaotic receiver estimation engine. This estimation engine both synchronizes and recovers data by mapping probability calculation results onto the chaotic dynamics via a strange attractor geometrical approximation. For synchronization, the system does not require either a stable/unstable subsystem separation or a chaotic system inversion. The techniques employed can be implemented with any chaotic system for which a suitable geometric model of the attractor can be found.
Chaos is an area of science and mathematics that is characterized by processes that are nonlinear, such as equations that have a squared or higher order term. Chaotic processes are iterative, in that they perform the same operations over and over. By taking the result of the process (equations) and performing the process again on the result, a new result is generated. Chaos is often called deterministically random motion. Chaotic processes are deterministic because they can be described by equations and because knowledge of the equations and a set of initial values allows all future values to be determined. Chaotic processes also appear random since a sequence of numbers generated by chaotic equations has the appearance of randomness. One unique aspect of chaos compared to an arbitrarily chosen aperiodic nonlinear process is that the chaotic process can be iterated an infinite number of times, with a result that continues to exist in the same range of values or the same region of space.
A chaotic system exists in a region of space called phase space. Points within the phase space fly away from each other with iterations of the chaotic process. Their trajetories are stretched apart but their trajectories are then folded back onto themselves into other local parts of the phase space but still occupy a confined region of phase space A geometrical shape, called the strange attractor, results from this stretching and folding process. One type of strange attractor for a chaotic process called the Rossler system is depicted in FIG. 1, and illustrates the stretching and folding process. The chaotic attracter exists in perpetuity in the region of phase space for which the chaotic system is stable.
In an unstable system, two points in phase space that are initially close together become separated by the stretching and the folding, which causes the points to be placed correspondingly farther apart in the phase space than they originally were. Repeating the process (iterating) accentuates the situation. The points not only diverge from each other, but both trajectories move toward infinity and, therefore, away from the stable region of perpetual chaotic existence.
The sequences of points that result from two closely spaced initial conditions become very different very quickly in chaotic processes. The Henon chaotic system, for example, has been shown to start with two initial conditions differring by one (1) digit in the 15th decimal place. The result was that within 70 iterates the trajectories were so different that subtracting them resulted in a signal that was as large as the original trajectories"" signals themselves. Therefore, the stretching and folding causes the chaotic process to exhibit sensitive dependence on initial conditions. A receiver without perfect information about a transmitter (a xe2x80x9ckeyxe2x80x9d) will be unable to lock to the transmitter and recover the message. Even if a very close lock were achieved at one point in time, it is lost extremely quickly because the time sequences in the transmitter and receiver diverge from each other within a few iterations of the chaotic process.
Chaotic nonlinear dynamics may be utilized in telecommunications systems. There is interest in utilizing and exploiting the nonlinearities to realize secure communications, while achieving reductions in complexity, size, cost, and power requirements over the current communications techniques. Chaotic processes are inherently spread in frequency, secure in that they possess a low probability of detection and a low probability of intercept, and are immune to most of the conventional detection, intercept, and disruption methods used against current xe2x80x98securexe2x80x99 communications systems based on linear pseudorandom noise sequence generators. Chaotic time sequences theoretically never repeat, making them important for such applications as cryptographic methods and direct sequence spread spectrum spreading codes. In addition, chaotic behavior has been found to occur naturally in semiconductors, feedback circuits, lasers, and devices operating in compression outside their linear region.
Unfortunately, many of these characteristics also complicate the task of recovering the message in the chaotic transmission. A fundamental problem permeating chaotic communications research is the need for synchronization of chaotic systems and/or probabilistic estimation of chaotic state, without which there can be no transfer of information. Without synchronization, meaning alignment of a local receiver chaotic signal or sequence with that of the transmitter, the characteristic of sensitive dependence on initial conditions causes free-running chaotic oscillators or maps to quickly diverge from each other, preventing the transfer of information. Probability-based estimates of chaotic state are typically made via correlation or autocorrelation calculations, which are time consuming. The number of iterates per bit can be reasonable in conjunction with synchronization, but values of several thousand iterates per bit are typically seen without synchronization.
A general communications system employing chaos usually consists of a message m(t) injected into a chaotic transmitter, resulting in a chaotic, encoded transmit signal y(t). This signal is altered as it passes through the channel, becoming the received signal r(t). The receiver implements some mix of chaotic and/or statistical methods to generate an estimate of the message me(t).
The recovery of a message from transmitted data depends on the ability of the receiver to perform either asynchronous or synchronous detection. There are three fundamental approaches to chaotic synchronization delineated in the literature of the prior art: (1) decomposition into subsystems, (2) inverse system approach, and (3) linear feedback.
If the approach is a decomposition into subsystems, the chaotic system is divided into two or more parts: an unstable subsystem usually containing a nonlinearity and one or more stable subsystems. The stable subsystem may contain a nonlinearity if its Lyapunov exponents remain negative. The Lyapunov exponents of all subsystems must be computed to evaluate the stability or instability of each one, where negative Lyapunov exponents indicate stability and positive Lyapunov exponents indicate instability. The arbitrary division into stable and unstable systems is accomplished by trial and error until successful. The driver or master system is the complete chaotic system, and the driven or slave system(s) consists of the stable subsystem(s). In general, synchronization will depend on circuit component choices and initial conditions.
The problem with using the decomposition approach is threefold. First, the decomposition into subsystems is arbitrary, with success being defined via the results of Lyapunov exponent calculations. There is presently no known method by which to synthesize successful subsystem decomposition to satisfy a set of requirements. Second, the evaluation of Lyapunov exponents can become extremely involved, complicated, and messy. The time and effort spent evaluating a trial, arbitrary decomposition can be extensive, with no guarantee of success. Third, there can be several possible situations for the subsystem decompositions for a given chaotic process. A chaotic process could have single acceptable decomposition, multiple acceptable decompositions, or no acceptable decompositions. Since the method is by trial-and-error and without guarantee of success, a general approach that will work for an arbitrary chaotic process is highly desirable.
In the inverse system approach, the receiver is designed to invert the chaotic function of the transmitter. For appropriate choices of transmitter systems and initial conditions, inverse systems can be designed into a receiver that results in perfect recovery of a noiseless transmitted message. However, one major drawback of using the inverse system approach is that signal noise results in erroneous message recovery. In addition, the invertible system must be based on a specially designed chaotic process since generic chaotic signals are not invertible. The collection of specially designed invertible chaotic processes is very small. This seriously limits the repertoire of receiver designs as well as the library of applicable chaotic process choices. Hostile countermeasures designers would have a relatively easy time analyzing and compromising the small set of systems that could be developed using these invertible chaotic functions.
In the linear feedback system approach, a master-slave setup is used in which the output of the slave system is fed back and subtracted from the received chaotic time sequence to generate an error function. The error function drives the slave system in a manner reminiscent of a phase-lock loop. Synchronization depends on the initial conditions of the master and slave systems. One drawback of linear feedback systems is that without a set of constraints on the initial conditions, synchronization of the master and slave systems cannot be guaranteed. In addition, the slave is a stable subsystem of the chaotic process, and is subject to the same drawbacks and limitations enumerated for the subsystem decomposition method above.
In addition to the three fundamental approaches to chaotic synchronization, there are four basic methods of encoding digital data into chaotic transmitted sequences: masking, orbit control, chaos shift key, and orthogonal autocorrelation sequence. They employ several different chaotic systems, with the most commonly mentioned including the Henon, Rossler, Lorenz, and Double Scroll (Chua""s circuit). Most of these methods have variations in their implementations. A common problem among them is the issue of transmitter-receiver synchronization.
Signal masking refers to the process of embedding a message in a free-running chaotic time series such that the message is hidden, the chaotic dynamics are not altered enough to preclude synchronization, and the chaotic noise-like waveform is the dominant transmit feature. Signal masking consists of the message signal being added to a chaotic signal and recovered via subtraction of the synchronized receiver local chaotic signal from the received waveform. The masking signal requirements are satisfied when the message power has an embedding factor on the order of xe2x88x9230 dBc, which places the message power 30 dB below the chaotic power. Synchronization has been shown at higher information signal power levels, but with increased incidence of synchronization error bursts and degraded message recovery. One difficulty with this method is that noise power on the order of the message signal power level results in erroneous message recovery. The transmit SNR, which is determined by the power of the chaotic signal, must be very large in order to overcome the effects of modest channel noise which wastes power and broadcasts the signal presence (non-LPD). In addition, small trajectory perturbations, as little as the order of 10xe2x88x9216, can result in significant synchronization error bursts. Another difficulty for real implementations is that most synchronous chaotic systems can""t accommodate channel losses, because the receiver synchronization degrades when the received signal has been attenuated from its original transmitted value. Finally, an unintended listener can recover the message without knowledge of the chaotic system by performing a mathematical reconstruction of the chaotic attractor and using it in conjunction with a set of recent observations to make local predictions of the immediate future for the chaotic system. Sufficiently accurate results are obtained to subtract out the chaotic process and uncover the hidden message, thereby compromising the security of the chaotic communication.
Chaotic attractors consist of an infinite number of unstable periodic orbits, all of which will be approached eventually from any initial condition. The system trajectory will be repelled away from any given orbit because of the stretching and folding of the chaotic dynamics, but it will eventually return to within a small neighborhood of the same orbit for the same reason. Orbit control exploits this type of behavior to transmit information by controlling the system trajectory such that it stays in the vicinity of one or more orbits for a prescribed length of time or follows a predetermined sequence of orbits. This method is very sensitive to noise and relatively small perturbations to the transmitted signal can cause the receiver trajectory to drift out of the required orbit.
Using the chaos shift key method of encoding digital data into chaotic transmitted sequences, for a binary-valued data stream, an aspect of the chaotic system is altered to create a transmit data stream. One method is to toggle a chaotic system parameter value, causing the data stream to switch between two chaotic attractors. Alternatively, the output can be inverted or not (i.e., multiplied by +1 or xe2x88x921), causing the two attractors to be mirror images of each other. Both methods utilize a chaotic synchronization scheme as a precondition of message recovery. The message is demodulated either via the detection of synchronization with one of two attractors in the receiver (a hardware version of which is used with a Chua""s circuit), or by the statistical method of correlation between the received sequence and a local chaotic signal over a large number of samples.
The orthogonal autocorrelation sequence method of encoding digital data into chaotic transmitted sequences develops a system with signal properties such that multiple user signals can be combined at the transmitter and then separated at each receiver by an autocorrelation calculation. The technique is presented as a general design method independent of the chaotic system used for the transmitter, but heavy use is made of a specific chaotic process in developing the concepts and results. Reasons for developing this scheme include the claims that non-repeating chaotic carrier signals provide greater transmission security than periodic carriers, require neither acquisition nor tracking logic for successful detection, and are more immune to co-channel interference than periodic carrier methods. Implementation investigations have demonstrated that an extremely large number of received values is required to accomplish demodulation, severely restricting the message data rates.
The present invention is a communications system based on a chaotic estimation engine. The invention provides for efficient communication with as little as two iterates per bit, a very general synchronization scheme, the integration of statistical methods with chaotic dynamics in the data recovery calculations, algorithms to enable a maximum aposteriori transmitted value estimation, secure communication by using completely overlapping ranges of transmit values for the conveyance of a logical zero or a logical one, and the development of a signal-to-noise ratio (SNR) estimator that produces good estimates of the true channel SNR and tracks changes in the channel noise power over time.
A transmit sequence is derived that sends one version of the chaotic strange attractor for a logical one and another version for a logical zero. Several new computational techniques allow for the estimation of both the instantaneous and average signal-to-noise ratio (SNR) values, as well as the maximum a posteriori (MAP) transmitted value for a given received chaotic iterate.
The receiver synchronizes to the transmitted chaotic sequence without requiring a chaotic equation separation into stable and unstable components or the design of an invertible chaotic process as was done in previous systems. The two processes of chaotic synchronization and message recovery required for synchronous communications are interleaved in the receiver estimation engine algorithms, obviating the need for an independent effort to achieve the synchronization of the transmitted chaotic signal with a locally generated version in the receiver. The estimation engine has the ability to make accurate decisions with as little as two chaotic iterations per data bit.
Three different estimates are generated for each received value and then combined into a single initial decision. This initial decision is mapped onto the closest portion of the geometric structures used to model the chaotic attractors via a minimum Euclidean metric. This mapping results in the final receiver decision of the transmitted value for the current received iterate. The concluding step of combining the decisions for all iterates in a bit yields the receiver bit decision, which is the transmitted message recovery.
A nonlinear chaotic receiver comprises a component for receiving a chaotic encoded digital signal transmission from a chaotic transmitter, synchronizing the chaotic receiver with the chaotic transmitter and recovering the contents of the encoded chaotic digital signal transmission using a chaotic strange attractor model and a chaotic probability density function model. Synchronization of the chaotic receiver with the chaotic transmitter and recovery of the contents of the encoded chaotic digital signal transmission may occur in the same calculations and result concurrently from the same calculations. The chaotic encoded digital signal transmission is a data sequence comprising a first through N number of iterates, wherein the first iterate represents a first value in the data sequence and the Nth iterate represents a last value in the data sequence. The chaotic strange attractor model comprises using one chaotic sequence to represent a logical zero data state and using a second chaotic sequence to represent a logical one data state. The first and second chaotic sequences may have attractors with completely overlapping regions of validity and the attractors may be mirror images of each other. The attractors are modeled as a set of geometrical functions having defined regions of validity. The chaotic strange attractor model comprises a strange attractor generated by combining Henon and mirrored Henon attractors, wherein the Henon and mirrored Henon attractors are generated by starting with one or more arbitrary points within an area of phase space that stretches and folds back onto itself, and inputting the points to a set of Henon equations, the result being the Henon attractor, and taking a mirror image of the Henon attractor to form the mirrored Henon attractor where the strange attractor is represented as a set of parabolas displayed on a Cartesian coordinate system and the parabolic regions of validity of the strange attractor are determined. The chaotic attractor model determines any existing fixed point on the strange attractor that repeats itself through multiple iterations of the chaotic transmission. The data sequence of the received chaotic encoded digital signal transmission is randomly selected from the group consisting of a first logical state for the Henon attractor and a second logical state for the mirrored Henon attractor. The chaotic probability density function models the probability of the first and second logical states of the Henon and mirrored Henon attractors as a random selection. The Henon strange attractor is generated by using image calculations on a Henon map, is represented in a Cartesian coordinate system as a crescent-like shape which occupies all four quadrants of the Cartesian coordinate system and is modeled as a set of four parabolas. The contents of the encoded chaotic digital signal transmission is determined by generating an initial decision for the contents of each iterate and generating a final decision for the contents of each iterate using a decision and weighting function. The final decision is generated using a synchronizer and final decision function and the final decision is used to recover the data sequence. The contents of the encoded chaotic digital signal transmission are determined by generating three estimates for each iterate received and calculating an initial decision for each iterate and mapping the initial decision onto the chaotic attractor to form a final decision for each estimate. The three estimates comprise a first estimate which is the value of the received iterate, a second estimate which is a minimum error probabilistic estimate and a third estimate which is a final decision of the previous iterate processed through Henon and mirrored Henon equations. The three estimates are combined to form the initial decision through a weighted average using probability calculations for the first, second and third estimates.
A means for determining a synchronization estimate to synchronize the chaotic receiver with a chaotic transmitter that generates the encoded chaotic digital signal transmission is provided. Signal estimates of the value of the 1 through N iterates received are generated.
The signal estimates comprise a received value which is equal to the actual value of the received iterate, a maximum a posteriori (MAP) estimate and a decision feedback estimate. The decision feedback estimate comprises generating a first decision feedback estimate for iterate n by passing iterate (nxe2x88x921) through Henon equations and generating a second decision feedback estimate for iterate n by passing iterate (nxe2x88x921) through mirrored Henon equations.
The decision and weighting function comprises performing a probabilistic combination of the three signal estimates by finding a probability for each iterate for each received value, MAP estimate and decision feedback estimate, generating an initial decision for each iterate, selecting the feedback estimate closest in value to the received value and the MAP estimate, generating weighting factors used in a weighted average computation and performing a weighted average, calculating a discount factor to discount a final decision for received values close to zero, determining the Cartesian coordinate representation of the initial decision and passing the Cartesian coordinates of the initial decision to a synchronizer and final decision generator and passing the zero proximity discount value to a system to bit map function. The weighting factors comprise generating a first weighting factor that quantifies channel effects by using a transmit PDF window used in determining the MAP estimate and multiplying the channel effects weighting factor by a second weighting factor that uses a PDF selected from the group consisting of the received PDF and transmit PDF, the result being the weighting factor for each iterate which is passed to the synchronization and final decision function. A discount weight is calculated to reduce the impact of initial decisions whose receive values are close to zero.
The selection of the feedback estimate comprises calculating one dimensional Euclidean distances from the received value and MAP estimate to the first and second feedback estimates and selecting the feedback estimate with the minimum Euclidean distance.
The synchronization and final decision function uses an initial decision from the decision and weighting function and maps Cartesian coordinates of the initial decision onto a Cartesian coordinate representation of the strange attractor. The mapping comprises inputting the initial decision into parabola models, the parabola models comprising equations approximating Henon and mirrored Henon attractors and calculating two dimensional Euclidean distance between the initial decision and every point on all parabolas and selecting a point on an attractor model corresponding to a minimum Euclidean distance as the final decision of the value of each iterate. The transmitted data sequence is recovered by combining the final decision of iterates 1 through N to determine the encoded digital signal transmission data sequence.
The nonlinear chaotic receiver comprises a receiver estimation engine for synchronizing the chaotic receiver with a chaotic transmitter and recovering the value of an encoded chaotic digital signal transmission. The receiver estimation engine comprises a signal-to-noise ratio (SNR) estimator, a maximum a posteriori (MAP) estimator, a feedback estimator wherein the chaotic receiver and the chaotic transmitter synchronization and the encoded digital signal transmission recovery occur concurrently while executing the same set of calculations within the receiver estimation engine. The receiver also includes a decision and weighting function within the receiver estimation engine comprising determining the probability of the estimate produced by the SNR estimator, the MAP estimator and the feedback estimator for each received iterate. The receiver calculates an initial decision for the iterate, a discount weight for a final decision for received values in close proximity to zero, and determines the final estimate of each iterate based on the initial decision from the decision and weighting function and then combines the final decision of iterates 1 through N to recover the encoded digital signal transmission data sequence.
The present invention comprises a method in a computer system and computer-readable instructions for controlling a computer system for receiving and recovering the contents of a chaotic encoded digital signal transmission by receiving a chaotic encoded digital signal transmission from a chaotic transmitter, synchronizing the chaotic receiver with the chaotic transmitter, and recovering the contents of the encoded chaotic digital signal transmission using a chaotic strange attractor model and a chaotic probability density function model.

Receiver estimation engine for a chaotic system


The preferred embodiment of an apparatus for ski pole retention and storage is provided. A proximal half of a cuboid bracket embodied in a U-shape is substantially connected, via a hinge, to a distal half of a cuboid bracket embodying the same characteristics. Both the proximal and distal halves are secured with a binding strap and ratchet located on the plane opposite the hinge. The preferred embodiment also comprises of elastic straps that bias the apparatus to an open position. A binding strap is substantially fixed to said proximal half and said binding ratchet is substantially fixed to said distal half. Both the proximal and distal halves of the cuboid bracket have interior surfaces to which high-density foam is substantially connected. The exterior surface of the proximal half of the cuboid bracket comprises a second mechanism by which it attaches the body of the apparatus to a rigid surface.

Ski poles are commonly used in cross-country or mountain slope skiing and less commonly in snowboarding. While not typically employed during a user's decent, the use of ski poles while riding a snowboard becomes particularly useful when traversing flat land. Ski poles are desirable in traversing terrain because they allow the user to create an anchor point in the snow or other various substrate from which to generate momentum and alter trajectory. While useful, if not necessary, to traverse flat land while on snowboard, the use of ski poles while the user descends the slope of a mountain is most often a hindrance. In downhill skiing, the user uses the ski poles to generate momentum, redirect momentum and to provide balance. When properly used, ski poles are held in the hands with the body of poles extending downward longitudinally and travel parallel to the skis and, consequentially, the path of the user. Conversely, during snowboarding the user, as well as the path of travel for the ski poles, is oriented perpendicular to the snowboard. This perpendicular orientation disrupts the user balance and may possibly cause the ski poles to contact the snow thereby limiting the angle at which the user may lean into a turn. Accordingly, this change in orientation makes the use of the ski poles during descent increasingly difficult and unsuitable for snowboarders.
The retention and storage of ski poles has traditionally been inefficient. Common problems with previous storage methods include a low speed of deployment and subsequent storage, the possibility of injury resulting from being struck or impaled by the ski poles during a crash and limitations to the maneuverability of the user. For example, a solution that places the storage mechanism on the arm of a user presents a substantial risk of injury in the event of a crash. Specifically, the inherent flexibility of the user's arm may redirect the point of the ski poles towards the body upon impact. What's more, the sudden deceleration from 25-30 MPH during the event of a crash may potentially cause the ski pole, if not fixed to a rigid object, to strike, impale or lacerate the user.
Additionally, solutions which would place the storage apparatus on the user's back greatly diminishes the user's ability to deploy and subsequently store the ski poles. Beyond the dangers of bodily injury previously mentioned, the human anatomy's resistance to posterior external rotation of the shoulders makes reaching the poles and/or mechanism holding same extremely difficult and results in the need to remove any storage device from that anatomical plane before it can be addressed with any precision. Thus, in order for a user to store ski poles in a backpack or similar system, the user must first remove that system from its carried position before they are able to access the ski poles, making the deployment and storage of said ski poles a slow, cumbersome process.
Furthermore, previous methods of securing ski poles in other fixed positions have been unsuccessful. A simplistic approach of utilizing fabric hook and loop fasteners, or any other friction-based securing method, fails on two fronts. First, the aforementioned method does not possess the requisite strength to secure the ski poles in their intended position during impact. The mere contact with the snow on the extremities of the ski pole while traveling at even casual speeds has the potential to generate enough force to separate the two halves of the fabric hook and loop fasteners resulting in the ski poles become dislodged or lost. Second, fabric hook and loop fasteners, or other friction-based securing methods are prone to fail as they come into contact with snow and ice. Additionally, when the halves of the fabric hook and loop fasteners are left unsecured, the buildup of snow, ice or water may disrupt the interface of the hook and loop causing subsequent closure to be inefficient or impossible.
Accordingly, there is a need in the art for a ski pole retention and storage apparatus that allows for fast deployment and storage, is easy to use and reduces the likelihood of injury upon impact. Additionally, the desired device should not interfere with the user's maneuverability while traversing flat lands or slopes. Moreover, the desired device should be capable of fixation to the body of existing equipment. Other objects and advantages of the invention will be apparent from the drawings and detailed description to follow.

Ski pole retention and storage apparatus