New consumption and inventory recording, tracking, analysis and control techniques are provided. In some aspects of the invention, multiple master tags and signal control elements manage the communication of unique signals indicating and managing inventory status and consumption activity. A master tag may bridge communication from a computer hardware and software control system to smaller, more shielded inventory tags, to assess unique identifying information and control actuation of various functions. In other aspects, drugs and other agents may be variably released and/or applied by a new form of actuable, consumable tag with multiple signal elements.

Human beings have implemented purposeful diets, exercise, medical regimens and other activities and routines ("personal activities") for centuries, in an effort to restore, maintain or enhance personal health and physical performance.
In recent years, research has confirmed that the degree, frequency and type of personal activities can have profound affects on a person's overall morbidity and mortality. For example, it has long been understood that sedentary lifestyles are strongly associated with adverse health conditions and the risk of premature death. Flowing from this, millions of Americans now attempt to follow the advice of health professionals that they should make an effort to exercise frequently. When provided, a physician's specific advice may vary widely, but guidelines from the Centers for Disease Control recommend: (1) a minimum of 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity, and (2) muscle-strengthening activities on 2 or more days a week that work all major muscle groups, among other possible regimen combinations for health benefits.
Strikingly, a majority of patients are still not advised to exercise at all by their physician, even in the face of recent studies establishing that a majority of adults in the United States are overweight or obese.
In recent years, the sufficiency and soundness of general advice on exercise from health authorities has been called into question by empirical research. Several studies now demonstrate that even a high level of regular, moderate-to-vigorous exercise may be insufficient to offset the destructive effects of time spent sitting. Findings like these are extremely important today, because more and more workers in the United States spend most of their time sitting at work—specifically, while working at personal computer terminals. Many of these workers continue to labor under the delusion that, if they spend a half an hour at the gym on a lunch break or after work, they can offset the effects of a sedentary work routine. In fact, some studies may even support the disturbing conclusion that a person may actually be less active, overall, on days that they make an effort to exercise vigorously, offsetting the benefits.
Adherence to medical regimens and compliance with consumption-related instructions from medical and fitness personnel also presents long-standing, serious challenges for millions. In recent years, a plethora of medical compliance tools (such as reminder systems and calendared medicine containers) have flourished, but the issue of compliance with such regimens continues.
It should be understood that the disclosures in this application related to the background of the invention, in, but not limited to this section titled "Background," do not necessarily set forth prior art or other known aspects exclusively, and may instead include art that was invented concurrently or after the present invention and conception, and details of the inventor's own discoveries and work and work results.

Object condition analysis and control techniques

Abstract: A computer display with specialized software may comprise part of the control system, and may reflect, provide, and/or receive modified data signals to and from such tags and signal elements.

Abstract: In other aspects of the invention, an administrative user may use a GUI to access information concerning, and control, consumption by a consumer user.


A pressurized brake bleed system includes a rigid container, a flexible container containing brake fluid disposed within the rigid container, a hose having one end connected to the flexible container and another end for connection to a fluid reservoir of a brake system and a structure to apply a force to pressurize the flexible container to bleed the brake fluid from the flexible container through the hose to the fluid reservoir.

There are several methods of bleeding a brake system for a motor vehicle. For example, when bleeding the brake system at an assembly plant, one method involves the use of a vacuum evacuation and brake fluid fill system. Such a vacuum evacuation and brake fluid fill system is disclosed in U.S. Pat. No. 5,088,529 which issued Feb. 18, 1992. That vacuum evacuation and brake fluid fill system is mounted to a filler tube of a master cylinder of a brake system and has a controller for directing the operation of the system to evacuate the brake system and pressure fill the brake system with brake fluid. In so doing, this method results in using a system which is expensive, cumbersome and needs a pressure and vacuum source.
When bleeding the brake system in the after market, another method involves the use of a bleeder ball system. The bleeder ball system includes a spherical ball filled with brake fluid and a hose to attach the ball to a fluid reservoir of a master cylinder of the brake system. The bleeder ball system is connected to a constant source of air pressure to push air bubbles from the brake system as a fitting or bleeder tube is opened. In so doing, this method results in using a system which is expensive, messy and needs a constant air pressure source.
Still another method of bleeding the brake system in the aftermarket is to open bleed ports or fittings in the brake system and then apply the brakes pushing the brake pedal to the floor. While the brake pedal is depressed the bleed ports or fittings are closed and then the brake pedal is released and fluid is compensated into the system from the fluid reservoir. In this method, an operator manually fills the fluid reservoir to compensate for the fluid being bled through the system. This method can result in excess brake fluid spilling over the workplace, being messy, laborous and cumbersome and it is difficult to flush all air from the brake system. Thus there is a need in the art to provide an inexpensive, aftermarket pressurized brake bleed system.


A method (200) of creating pairwise combinatorial test cases from system configuration data can include reading a graphic representation of the system configuration data (210, 230, 260). Within the graphic representation, parameters can be represented by nodes and parameter can be represented by flows linking the nodes. The method further can include identifying paths of flows through the graphic representation until each parameter value of the graphic representation has been paired with all values of each other parameter of the graphic representation (205). Each path can specify a pairwise combinatorial test case.

1. Field of the Invention
The present invention relates to system testing and, more particularly, to developing test cases from data to be provided to a system under test.
2. Description of the Related Art
Adequately testing software-based systems can be a complex and costly endeavor. To test a system with approximately 100,000 lines of code, for example, a significant number of test scenarios would be required along with several months in which to conduct the testing. A test scenario, or test case, refers to a combination of input parameters, internal events, external events, and the like, which influence the internal operation of the software-based system that is undergoing testing. Typically, even a simple software system has such a large number of parameters that testing each possible test case is difficult, if not impossible.
The increasing complexity of software systems has given rise to the need for suitable testing methodologies. One such technique is referred to as the combinatorial design method. The combinatorial design method can reduce the number of test cases needed to check the functionality of a software-based system. Generally, for a given software-based system, there are too many parameter combinations to test all possible scenarios or internal states. The combinatorial design method aids the tester in selecting which scenarios to test. In the combinatorial design approach, the tester generates tests that cover all pairwise, triple, or n-way combinations of test parameters specified in formal test requirements. Covering all pairwise combinations means that for any two parameters, p1 and p2, and any valid values v1 for p1 and v2 for p2, there is a test in which p1 has the value v1 and p2 has the value v2.
Software-based tools have been developed which construct pairwise combinatorial tables of test parameters. Available tools derive the pairwise combinatorial tables from tabular input data of test parameter information. While such tools are useful in terms of testing, requiring input data in tabular form does have limitations. In particular, when data is presented in tabular form, it can be difficult to indicate relationships and dependencies between multiple parameters and value choices. This can complicate test case development for test personnel. Further, it is difficult to associate supplemental data with test parameters when the parameters are specified in tabular form.
It would be beneficial to provide a more intuitive and reusable methodology for developing test cases which overcomes the deficiencies described above.

Method and apparatus for generating pairwise combinatorial tests from a graphic representation


This invention discloses a fastener for fastening a carry bag to a person's body, characterized by a garment having at least one reinforced member. The reinforced member is integrally formed with the garment. It has an elongate strap and a container portion of a backpack or rucksack. The reinforced member includes connector means for connecting the reinforced member to an engagement means of the carry bag. The garment may be, for example, a waistcoat, collared vest or a front portion of a waistcoat or collared vest that extends to a carry bag, rucksack, or backpack.

Backpacks have been known for many years and take a variety of forms, but nowadays in addition to its functional purpose, backpacks also need to be aesthetically pleasing to fit in with the appearance and/or 'image' of the wearer thereof. In the past, backpacks had been used as a primary means of transporting education materials to and from, for example, a school. This has changed and young people are increasingly purchasing backpacks only if they are suitably fashionable and attractive, in addition to being useful.
A backpack is very easy to carry around but many consider backpacks to be childish and meant for students only. Backpacks and, in particular, their straps are often considered unappealing as they differ in colour from the attire worn by the wearer. The straps, which extend over the wearer's shoulders and onto a front portion of his or her upper body, are always prominent and this contributes to conventional backpacks being unlikeable, especially by teenagers and students who commonly refer to it as the unprofessional backpack strap effect.
This invention attempts to, at least in part, address the above issues and provide a carry bag that is more appealing to a wider range of people.

Garment, carry bag, and fastener for fastening a carry bag to a person's body


The invention relates to a male connector for a liquid circuit, comprising: a distal connection piece comprising a tubular part that defines a passage; a proximal connection piece; a joining member extending in a fixed and co-axial manner in the tubular part of the distal connection piece, the joining member being formed by a tubular body on which is fixed, at a free end, a cylindrical valve which is elastically deformable and closed at a distal end by a valve thickness traversed by a slit; and a sliding ring mounted on the tubular body, the sliding ring being movable between an inactive position, in which it encapsulates the walls of the valve, leaving the distal end of the valve free, and a connection position, in which it is situated at a distance from the distal end of the valve and exposes all or part of the lateral walls of the valve.

The invention relates to a connector for a fluid circuit, particularly for medical use.
Such a secure connector is known from document EP 0 544 581, comprising a distal entry cone of the female "Luer" type designed to be connected with a device having a compatible and complementary male "Luer" type connector. The distal entry cone is plugged by a septum or membrane having a flush surface which is easily cleanable to remove germs or bacteria prior to making a connection. The septum protects a tube which, once the connection is made, extends partially into the hole in the male "Luer" type connector which is connected to it. Once connected, the connector of document EP 0 544 581 has a straight tubular passage and reduced dead volume. The connector described in document EP 0 544 581 is a secure female connector.
A secure connector set for a liquid circuit was then proposed in international application PCT/EP 2011/052315, including a male connector and a female connector, each including a proximal coupler and a distal coupler. The distal coupler of each of the connectors defines a passage and includes a tubular part wherein extends coaxially a connection member fixedly mounted on the proximal coupler, and an elastically deformable, substantially tubular membrane, closed at a distal end by a membrane body. The membrane of each connector is movable between a plugging position, wherein the membrane sealingly covers a free end of the connection member, and an connecting position wherein the connection member passes through the membrane. Moreover, the tubular part of the distal coupler of the male connector is designed to be inserted, upon connection, into the tubular part of the distal coupler of the female connector, such that in a plugging position, for each of the male and female connectors, the membrane sealingly blocks the passage in the distal coupler.
This connection set has the advantage of reducing the number of steps needed for its assembly by an operator. Moreover, it includes easily cleanable connection means, particularly at the distal parts of the connectors, in that the membranes are flush with the distal end of the connectors.
Moreover, document WO 2006/062912 describes a sealing male Luer connector which can be fixed to a standard female Luer valve for the purpose of opening a flow channel between the two. To this end, the male connector includes a rigid housing having a distal end provided with a rigid male Luer connector and a proximal end at which a proximal seal is formed. The distal end of the housing includes a valve seat. A resilient biasing member is positioned inside the compartment, this member biasing an actuator into contact with the valve seat so as to prevent fluid flow through the male connector. Upon engagement with a female connector, the actuator is moved in the proximal direction to open the distal valve and then the proximal seal. A partial vacuum is formed within the male connector upon disengagement with the female connector, so as to aspirate liquids on the external surface of the distal end of the male connector into the male tip.
Document WO 00/20070, for its part, describes a needleless penetrating point connector having a hollow spike, a female Luer, a flexible and resilient spike boot having a tip and a spring portion extending above the spike, a centering member covering a portion of the spike boot and a resilient swabbable septum placed between the centering member and one end of the female Luer. The hollow spike and the female Luer are fastened together and terminate the assembly. The length of the Luer and/or the length of the spike are such that, when a male Luer is pushed into the female Luer, it urges a pressure on the septum and presses it toward the spike so that the tip portion of the boot is pierced by the tip of the spike. When the septum is further compressed, it extends above the spike, so that the cavity of the point is in fluid communication with the male Luer hub. This injection port causes minimal reflux and the septum constitutes a swabbable double antibacterial barrier over the spike.
Finally, document WO 2008/052140 describes a medical connector including a rigid housing, a rigid internal member positioned inside the housing and comprising at least one lateral opening, and a hollow flexible member positioned inside the housing, a protrusion whereof is designed to penetrate into the lateral opening.
It is important for these medical liquid circuit connectors to limit or eliminate the risks of drop formation at the outlet of the connectors at the time of their separation. Indeed, the products transferred through these connectors are generally more or less dilute medicines, which can therefore be dangerous for exposed users or patients, as can be the case for those preparing medicines. The formation of drops at the outlet of the connectors can also be the source of cross-contamination in the preparation of the medicines themselves.

Non-drip, direct-flow connectors with secure locking


The present disclosure relates to signal sending methods and apparatus. One example method includes generating a first data signal based on channel state information, receiving a second data signal sent by a primary transmitter, determining a phase of the second data signal, and sending the first data signal based on a phase of a first measurement signal sent by the primary transmitter and the phase of the second data signal sent by the primary transmitter.

A multiple-input multiple-output (MIMO)) technology has gradually become a mainstream signal transmission technology in a wireless communications system. The MIMO technology means that a transmitter includes a plurality of antennas. During signal sending, a transmitter may send signals to a plurality of receivers at a same time and at a same frequency. In addition, considering a problem of signal interference, a distance between each two adjacent antennas of the plurality of antennas of the transmitter needs to be greater than a specific value. Based on this, because a device size of the transmitter is limited, a quantity of antennas included in the transmitter is limited. In other words, when a signal is sent by using the MIMO technology, signal transmission efficiency is limited by the device size of the transmitter. Based on this, to further improve the signal transmission efficiency, a distributed MIMO technology is proposed. The distributed MIMO technology refers to coordinating a plurality of transmitters that are spatially independent of each other, to send signals to a plurality of receivers at a same time and at a same frequency, where each of the plurality of transmitters has an independent radio frequency link, and each transmitter may include a plurality of antennas. In this way, when a signal is sent, the data transmission efficiency can be further improved by deploying more independent transmitters, and it can be ensured that the device size of each transmitter does not need to be excessively large or complicated.
In the prior art, when the distributed MIMO technology is used to send a signal, each of the plurality of transmitters that are spatially independent of each other sends a signal by using a clock generated by a local crystal oscillator. In this case, none of frequencies and time of the transmitters is synchronous; a secondary transmitter in the plurality of transmitters may adjust a phase of a to-be-sent second data signal by measuring a phase of a first data signal sent by a primary transmitter, to implement time synchronization between the primary transmitter and the secondary transmitter.
However, in the prior art, if a signal-to-noise ratio of a first data signal received by a secondary transmitter is comparatively low, a comparatively large measurement error exists in a measured phase of the first data signal. In this case, if a phase of a second data signal is adjusted directly by using the phase of the first data signal, a comparatively large error may also exist in an adjusted phase of the second data signal. In this way, not only time synchronization between the secondary transmitter and a primary transmitter cannot be implemented, but also a larger time offset may be caused, leading to signal interference between the primary transmitter and the secondary transmitter.


An image forming apparatus and method produce, when 600 dpi image data is generated from 300 dpi image data, interpolated data of a pixel of interest by a two-value logical operation in a case where the image data about the periphery of the pixel of interest appertains to binary representation. When the image data is judged to appertain to an image of multivalued representation, the interpolated data of the pixel of interest is produced by a numerical operation. As a result, a 600 dpi picture of the same size can be printed and recorded in such a manner that outline sharpness and smoothness, which are characteristics possessed by a two-value image, are maintained at portions of the input 300 dpi image data that are two-value images while smoothness of the grayscale is maintained at portions of the input 300 dpi image data that are halftone images.

This invention relates to an image forming apparatus and method for forming/recording an image while maintaining the quality of a picture by converting resolution of image data.
Printers have recently been given a color printing capability and have come to be utilized by users and means for producing a variety of expressions. In particular, color page printers using electrophotography have become the focus of attention owing to their high-quality printing and high-speed printing capabilities.
A full-color, laser-beam printer, which is one type of color page printer, records a multiple-value colored image by a first process which involves performing a first development by causing a beam to scan a photosensitive drum in a main-scan direction, and then transferring the image to a recording medium such as recording paper on a transfer carrier, and by successive second, third and fourth processes that follow the first process.
An electrophotographic color-laser beam printer is known in which a color image is obtained generally by these four processes using Y (yellow), M (magenta), C (cyan) and K (black) color toners. Recent years have seen the practical application of printers in which halftone image data is received from a host computer as multiple-value information-signal data composed of, say, eight bits per pixel, without the data being binarized as by dithering. These printers output each pixel by printing it in multivalued form. Printers having a printing resolution on the order of 300 dpi (dots per inch), 600 dpi, etc., have been developed and manufactured.
FIG. 46 is a block diagram illustrating the construction of a color laser-beam printer according to the prior art. As shown in FIG. 46, a host computer 201p connected to a printer 202p sends image information, which has been created by application software or the like, in the form of a command or data to a controller 203p within the printer 202p via an interface (not shown).
While expanding the entered command or data to multiple-value (e.g., eight bits) bit data corresponding to pixels of 600 dpi in conformity with the command or data, the controller 203p sequentially plants the data as 600 dpi multivalued data in a buffer memory 108p and stores one page of data. In dependence upon the process timing of a printer engine 207p having a resolution of 600 dpi, the controller sequentially sends a 600 dpi multiple-value image signal to the printer engine to drive the engine in conformity with the image signal, thereby obtaining a color image.
In recent years, information storage devices, such as laser-beam printers, employing electrophotography have come to be used widely as output devices for computers. Owing to the advantages of high printing quality, silence and high speed, these information storage devices have led to rapid growth in the field of desktop publishing (DTP).
Furthermore, electrophotographic color printers have also been developed. Owing to improvements in the capabilities of components such as a controller, which is the image generating unit in a host computer or printer, these color printers handle not only monochromatic printing but also the printing of color images. These printers have been put into practical use and are gaining popularity.
Depending upon the type of color printer, several methods such as the dither method, density-pattern method and error-diffusion method are available as methods for printing a full-color image exhibiting tonality. A characterizing feature of a laser-beam printer is that resolution in the main-scan direction can be changed with comparative ease. For example, laser-beam printers employ pulse-width modulation (so-called PWM) in which grays can be expressed by changing the driving pulse width of a laser diode in dependence upon the value of image data.
In recent monochromatic page printers, the general trend has been to improve picture quality by introducing resolution improving techniques such as smoothing processing for detecting and smoothing the edges of characters and figures. In addition, high-resolution printers in which the resolution of the printer engine serving as the printing mechanism is on the order of 480 or 600 dpi have appeared on the market in place of those having a resolution of 240 or 300 dpi, which was the old standard. By incorporating the aforesaid smoothing processing technique in these high-resolution printers, printing quality has been improved remarkably in comparison with the conventional printers.
Accordingly, there is a need to improve the printing quality of color printers as well by applying resolution-improving processing to smoothen the edges of characters and figures.
In the printers mentioned above, however, the following problem arises owing to the enormous amount of information carried by the signals handled:
Specifically, image information possessing grayscale information for each and every pixel contains an extremely large quantity of information, namely (number of pixels).times.(number of grayscale bits). In this case, the image information must be transferred in conformity with the process speed of the printing process employed by the printer. In addition, an operation is necessary for transforming information indicative of the entered color space to gray-level information of the colors Y (yellow), M (magenta), C (cyan) and K (black).
In order to implement this, an apparatus has been put into practical use in which the printer side is provided with a buffer memory having a capacity equal to or greater than the maximum output size. Once input image information has been stored in the buffer memory, data is transmitted to the printer engine and printed out in accordance with the timing of the printer.
In a printer of this kind, however, memory capacity is very large. Consequently, in a case where resolution is 600 dpi and a multiple-value image of eight bits per pixel is entered to print out data in size A4, the required capacity of the buffer memory is 32 megabytes for each of the colors Y, M, C, K, for a total of 128 megabytes.
This leads to problems such as a major increase in the cost and size of the apparatus. Furthermore, the processing performance of the control unit (CPU) handling the data must be improved. This also is accompanied by higher cost.
Further, in the conventional color printers mentioned above, the image data is multivalued and one picture is reproduced by superimposing images, which are composed of toners of the four colors magenta, cyan, yellow and black, produced from the multiple-value image data. This means that the smoothing processing technique employed in monochromatic printers cannot be applied as is.
Moreover, the above-mentioned conventional color printers often deal with pictorial images such as photographs. This makes it necessary to distinguish between these pictorial images and images such as characters and figures for the sake of processing.
An object of the present invention is to provide an image forming apparatus and method in which memory capacity can be reduced by a wide margin, while a high picture quality is maintained, even when a resolution conversion is performed so as to raise the resolution of image data.
Another object of the present invention is to provide an image forming apparatus and method in which image conversion logic that differs depending upon the characterizing features of an image is applied to effect a conversion of resolution so that a smooth-edged image can be obtained.


Mechanisms and techniques provide a system to evaluate operational integrity of a data processing system such as an area augmentation system by obtaining at least one set of distribution data related to information processed by the data processing system. The set(s) of distribution data can include corrections information and integrity bounds information related to the corrections information. The system applies a moment generating function to the set of distribution data to produce a moment bounded distribution data result and compares the moment bounded distribution data result to an integrity limit to determine if the data processing system operates within an acceptable integrity threshold. The system can be used in real-time or non-real time with sets of distribution data that are non-Gaussian, non-symmetric and/or non-unimodal.

Many conventional implementations of data processing systems require that such systems operate with a high level of integrity. As an example, a data processing system such as a computer-based vehicle navigation, operation or control system must operate with a sufficient level of integrity and accuracy such that the designers and operators of such a system can trust the system to perform properly in order to avoid hazardous conditions (e.g., the production of hazardously misleading information) which may endanger human life or property. Due to the complexity of modem day computerized data processing systems such as signal-based vehicle navigation systems, performing a verification process to determine that such systems operate at a required level or threshold of integrity can be problematic for system designers.
As an example, consider a conventional data processing system such as a Global Positioning System (GPS) that vehicles or individuals might use for navigation purposes. Generally, a GPS system includes a constellation (e.g. twenty-four or more) of GPS satellite space vehicles that orbit the earth. Each GPS satellite continually transmits, from space, specially coded GPS satellite signals (i.e., radio signals) that GPS receiver devices in vehicles or carried by individuals can receive and process. According to a specific orbital arrangement of the GPS satellites around the earth, a GPS receiver device positioned in the air or on the surface of the earth is provided with between five and eight different visible (i.e., receivable) GPS satellite signals from respective orbiting GPS satellites. By receiving and processing GPS satellite signals from four or more GPS satellites according to certain GPS navigation algorithms (e.g., by measurement of code-phased arrival times of four different GPS signals), a GPS receiver device can compute an estimate of the receiver device's position in three dimensions (e.g., altitude, latitude and longitude or X, Y and Z), an estimate of the receiver device's velocity (if the receiver is moving), and a time offset for a clock operating within the receiver device based on satellite clock information in the GPS signals.
Navigation in three dimensions is the primary function of conventional GPS systems and receivers designed for navigation are manufactured by various vendors for use within aircraft, ships, ground vehicles, and for hand carrying by individuals. In addition, the GPS system may be used for positioning purposes, time dissemination, surveying and geographic research (e.g., studies of plate tectonic movement) as well.

Methods and apparatus for evaluating operational integrity of a data processing system using moment bounding


An inspection apparatus (40) for remote inspection of the trepan radius area (34) of the inlet sleeve (24) of a steam turbine (10). The apparatus (40) provides a sealed volume (50) between a pair of inflatable bladders (46,48) for the introduction of a liquid couplant for the immersion of ultrasonic transducers (42,44). A laser line generator (62) generates a beam of light visible through camera (60) which impinges upon the inlet bell seal (30) when the apparatus (40) is in a proper inspection position within the inlet sleeve (24). Guide vanes (56) provide centering and generate an insertion force during air assisted insertion of apparatus (40). Transducers (42,44) are indexed axially and circumfretially by the independent rotation of axial drive gear (72) and longitudinal drive gear (70) engaged with a pattern of gear teeth (69) formed as a combination of circumferential spur gear teeth and axial rack gear teeth cut into a single surface of a spline shaft (68).

This invention relates generally to the field of non-destructive examination, and more specifically to the non-destructive examination of portions of a steam turbine apparatus, and particularly to an apparatus and method for the remote inspection of the inlet sleeve area of a high pressure steam turbine.
Steam turbines are well known in the power generation industry. A steam turbine is a device operable to extract heat energy from a flow of high pressure, high temperature steam and to convert that heat energy into mechanical energy in the form of the rotation of a shaft. The steam flow may be generated by any known type of steam generator, such as for example a fossil fueled boiler or a nuclear powered steam supply system. The rotating shaft of the turbine is commonly connected to a rotor shaft of an electrical generator to further convert the mechanical energy of the rotating shaft into electrical energy for distribution via the electrical power grid.
A typical steam turbine is illustrated in FIG. 1. The steam turbine 10 includes a rotor shaft 12 journaled for rotation within an inner cylinder 14 and an outer cylinder 16. The inner cylinder 14 includes, among other parts, a blade carrier ring 18 and several nozzle chamber units 20 each welded to the inner cylinder so as to become an integral part thereof. The outer cylinder 16 includes one or more high pressure steam inlets 22 and a number of inlet sleeve units 24, each of which extends inwardly in telescoping relation to its associated nozzle chamber 20 in the inner cylinder 14. Steam enters the turbine inlet 22 from a high pressure steam line (not shown) downstream from one or more control valves (not shown), into a nozzle chamber 20 integrally attached to the inner cylinder 14. The steam then passes through the nozzle and control stage rotating blades 26 that are attached to the rotor shaft 12. Steam from several parallel inlet paths flows into a control stage chamber 27 and around the various nozzle units 20 to merge together to flow through the remainder of the turbine array of stationary 28 and rotating 29 blade rows. The expanded steam exiting the last blade row enters a steam outlet annulus 36 formed between the inner and outer cylinders 14, 16 and is directed to an outlet 38.
The inlet steam flow must pass between the inner and outer cylinders 14, 16 without leakage between the cylinders. This requires a static seal that will withstand extremely high pressures, high temperatures, and differential thermal expansion. The seal must be substantially fluid tight and stable under conditions of extremely high velocity and sometimes pulsating steam flow. Dynamic instability, vibration and thermal shock are repeatedly encountered in use by the seal assembly. It is know to use a bell seal 30 for this application. Several known designs of such bell seals are described in U.S. Pat. No. 3,907,308 dated Sep. 23, 1975; U.S. Pat. No. 4,802,679 dated Feb. 7, 1989; and U.S. Pat. No. 4,812,105 dated Mar. 14, 1989.
Reliable operation of a steam turbine is desired in order to ensure the integrity of the electrical power supply and to avoid unplanned, and therefore more costly, repairs resulting from failures during the operation of the turbine. A variety of routine inspections are performed on a steam turbine to assess the condition of the machine during its useful operating life, and to detect degraded conditions before they mature into a part failure. The inlet sleeve area of a turbine is subject to extremes of temperature, thermal shock, vibration, and differential expansion, and as such, is an area vulnerable to mechanical wear and cracking. In particular, it is known that the surface 32 of the inner cylinder 14 in contact with the bell seal 30 is subject to wear. Such wear can result in a decrease in the effectiveness of the bell seal 30 and a greater leakage between the inner cylinder 14 and the outer cylinder 16 than desired. Furthermore, the trepan radius area 34 of the outer cylinder inlet sleeve 24 has been known to develop high cycle fatigue cracks in some turbines. It is known to inspect portions of a steam turbine by inserting a miniature camera into the turbine through the main steam inlet nozzle 22, such as is taught by U.S. Pat. No. 5,164,826 dated Nov. 17, 1992. However, inspections of the bell seal and trepan radius areas 30, 34 have previously been performed with the turbine out of service and with the turbine casing disassembled to provide access to these parts. Consequently, these inspections are time consuming and expensive.
Once the turbine is disassembled, the bell seal 30 may be visually inspected and measured for wear. The trepan radius area 34 is, however, too restricted to permit a reliable visual inspection. It is known to inspect this area with a special magnetic rubber material. The trepan radius area 34 must first be cleaned of accumulated scale and dirt such as by grit blasting. Special bladders are inserted into the trepan groove 35 to provide a sealed cavity therein. A multi-loop coil is wrapped around the outside of the inlet sleeve 24, and a liquid magnetic rubber material is then pumped into the sealed cavity. An electrical current is passed through the multi-loop coil to produce a magnetic field within the inlet sleeve 24. Cracks in the trepan area 34 will act as flux leakage sites and will draw small magnetic particles in the liquid magnetic rubber material toward the flux leakage sites. As the liquid rubber solidifies, this build up of magnetic particles is captured and can be interpreted as an indication of cracks in the trepan area 34 by a skilled non-destructive examination technician. This type of inspection is generally performed only during scheduled turbine maintenance outages when the turbine is being disassembled for other purposes, and the information provided about flaws in the trepan radius area is affected by the inherent limitations of electromagnetic testing techniques.
Thus there is a particular need for an inspection technique that provides an improved non-destructive examination of the turbine inlet sleeve area without the need for the disassembly of the turbine.
Accordingly, a method of inspecting the inlet sleeve area of a steam turbine is described herein, the method comprising the steps of: providing an inspection tool adapted for insertion into a steam inlet of the steam turbine, the inspection tool including a spaced pair of inflatable bladders and an ultrasonic transducer disposed there between; inserting the inspection tool into the steam inlet and moving it into an inspection position proximate the inlet sleeve; pressurizing the pair of inflatable bladders to form a sealed area surrounding the ultrasonic transducer; introducing liquid couplant into the sealed area; operating the ultrasonic transducer to perform a non-destructive examination of the inlet sleeve area; depressurizing the pair of inflatable bladders; and withdrawing the inspection tool from the steam inlet. The method may further include the steps of: providing a source of light and a camera on the inspection tool; and monitoring the output of the camera during the step of inserting the inspection tool to identify the inspection position when light produced by the source of light impinges upon a predetermined structure proximate the inspection tool.
An apparatus for implementing the disclosed method of inspecting the inlet sleeve of a turbine is also described. The apparatus includes a guide tube adapted for insertion into a steam line connected to a turbine; an ultrasonic transducer movably connected about an inspection section of the guide tube for remote operation of the transducer; an actuator connected between the guide tube and the ultrasonic transducer for selectively and remotely moving the transducer relative to the inspection section for inspecting a surrounding structure; a leading inflatable bladder and a trailing inflatable bladder each attached about the guide tube on opposed sides of the inspection section; and a couplant supply line having an opening between the leading and trailing inflatable bladders for selectively and remotely providing couplant to a volume between the leading and trailing bladders including the ultrasonic transducer. The apparatus may also include an optical positioning device attached to the guide tube for providing a remote indication of the position of the inspection section. The optical positioning device may be a laser for projecting a beam of light; and a camera for remotely monitoring the location of impingement of the beam of light.
A tool for providing both axial and rotational movement of the ultrasonic transducer in the inspection apparatus may include a shaft having an axis; a pattern of spur gear teeth formed on a first portion of the surface of the shaft, the pattern of spur gear teeth formed in a circumferential direction about the surface of the shaft; a pattern of rack gear teeth formed on the first portion of the surface of the shaft, the pattern of rack gear teeth formed in a longitudinal direction about the surface of the shaft; a driven oscillator gear engaged with the pattern of spur gear teeth for imparting rotation of the shaft about the axis; and a driven axial spur gear engaged with the pattern of rack gear teeth for imparting axial movement of the shaft along the axis.

Steam turbine inlet sleeve inspection apparatus and method


A method to determine a relative position between antennae comprising generating phase carrier measurements for a carrier frequency and at least three antennae including a master antenna and other antennae, generating phase integer sets based on the phase carrier measurements, and calculating a relative position between the master antenna and at least one other antenna based on the generated phase integer sets and a fixed baseline between two of the other antennae.

Existing requirements for providing precision approach and landing navigation during flight for both commercial and military aircraft include accuracy, integrity, availability, and continuity of function. Traditionally, location determination incorporates the use of global positioning system (GPS)-based satellite navigation that can provide accuracy down to the centimeter level. The integrity of a navigation system is typically expressed in terms of confidence levels. The higher the confidence level, the more reliable the information provided. Availability and continuity provide assurances that the system will be available not only at the beginning of the operation, but throughout the entire duration of the flight.
Meeting these requirements is especially crucial for autonomous shipboard landings on seaborne aircraft carriers. Proposals of using GPS to generate relative navigation and guidance to meet these challenges can provide the accuracy and integrity required, however, a shipboard approach and landing is more demanding than typical land-based approaches and landings. Aircraft navigation systems used in a shipboard approach and landing must continue to meet the requirements listed above even at sea under severe weather conditions and demanding electromagnetic environments. This is particularly important when landing on an aircraft carrier, where vertical landing errors of more than 0.3 meters is unacceptable and can result in unsafe landing conditions.
Some of the factors to consider during autonomous shipboard landings are a lack of visibility, operating under combat conditions, and a dynamically changing touchdown point. In addition to low rate GPS measurement data other, higher rate, measurements are needed in order to evaluate the relative state between aircraft and aircraft carrier, i.e., the aircraft's position and velocity with respect to the moving runway and touchdown point, as accurately as possible during a precision approach and landing. Existing navigational aids include using an inertial navigation system (INS) to measure the position and altitude of the approaching aircraft in conjunction with GPS. With a combination GPS/INS solution, the short-term measurement data from the INS, which is susceptible to drift errors over time, is corrected by the exact location and time references provided by satellite navigation.
Rapid and high-precision positioning with a Global Navigation Satellite System (GNSS) is feasible only when very precise carrier-phase observations can be used. Raw carrier phase measurements are generally the by-product of all GPS receivers. These phase measurements cannot be used as "range" observations because they are ambiguous.
Carrier phase measurements are ambiguous by an unknown, integer number of cycles. These integer ambiguity parameters need to be resolved before carrier-phase observations can begin to serve as very precise range measurements. For precise navigation, reliable real-time ambiguity resolution is necessary. For short-distance baseline, with current GPS, the reliability of ambiguity resolution with single-epoch data is not high. This makes it impossible to realize real-time precise navigation for safety-related applications. For medium- and long-distance baselines, with current GPS, it generally takes more than twenty minutes to get reliable ambiguity resolution. This low efficiency makes it impossible for global positioning system to be used in many applications where both high precision and high efficiency are needed.

Carrier phase interger ambiguity resolution with multiple reference receivers


A frequency resolution for measuring transmission characteristics of a device under test is increased. With a measuring device including a first terahertz light generator that generates incident light, a second terahertz light generator that generates reference light having an optical frequency f1−f2−fIF different from an optical frequency f1−f2 of the incident light by a constant difference frequency fIF, a terahertz light detector which outputs an light detection signal having the difference frequency fIF based on response light obtained by making the incident light incident to an optical fiber and the reference light, and a network analyzer that receives the light detection signal, thereby measuring characteristics of the optical fiber, a spectrum of the incident light (terahertz light) incident to the optical fiber includes the carrier frequency (f1−f2), but does not include sideband frequencies (f1−f2±fIF). It is thus possible to reduce the effective spectrum width of the incident light. As a result, the frequency resolution increases in the measurement of the transmission characteristics of the optical fiber.

There has conventionally been known measurement of transmission characteristics of a device under test in the terahertz region.
For example, there has been known a device which measures transmission characteristics of a device under test using terahertz light modulated by an intensity modulation according to FIG. 1 of International Publication WO2003/005002. Terahertz light having a carrier frequency (f2−f1) and side band frequencies (f2−f1±fIF) is made incident to a device under test. As a result, the effective spectrum width (referred to as "incident spectrum width" hereinafter) of the terahertz light incident to the device under test becomes twice (2×fIF) as wide as that of the modulation frequency fIF.
However, according to the prior art described above, the frequency resolution of the transmission characteristics of the device under test decreases. The wider the incident spectrum width becomes, the lower the frequency resolution of the measurement of the transmission characteristics of the device under test becomes.
If the modulation frequency fIF is then decreased in order to increase the frequency resolution, the measurement accuracy for measuring the group delay time of the device under test (group delay resolution) decreases.
In this way, it is not possible for the prior art as described above to increase both the frequency resolution and the group delay resolution at the same time.
An object of the present invention is to increase the frequency resolution for measuring the transmission characteristics of a device under test.

Measuring device, method, program, and recording medium


A method and system is described for enabling rapid access from voice-responsive interface processor to applications running on a plurality of connected host processors, each host processor using screens to communicate with the interface processor. The method is performed by the interface processor and includes the steps of: establishing virtual terminal session with each host processor that initializes applications on the host processor and places them in an idle state, awaiting further commands; responding to a user's request that requires one such application by accessing a virtual terminal session in existence with the host processor on which the application is running, entering user data in a screen from the application stored by the interface processor, and transmitting the screen with its entered data to the host processor, whereby the host processor immediately processes the screen; and transmits a new screen to the interface processor, the new screen containing data for the user. The interface processor then finds the data in the new screen and transmits it, via a voice interface, to the user.

Voice-based processing systems respond to user-telephoned inquiries by providing an intelligible voice response that provides requested information. Some transactions which are now performed on voice-based processing systems are:
The caller is requested to provide an account number via the telephone keypad, at which point, the processor employs the account number to find an account balance and returns the balance to the caller; PA1 The system provides a caller with information such as current interest rate; PA1 The system enters information from the caller into a data base, such as the status of a sales order or a repair call; PA1 The system places outgoing calls, automatically, for service orders or appointments, using data from a host computer.
Most voice-based processing systems employ an interface processor which includes a voice processing unit (VPU). A VPU replaces a human intermediary between the telephone and a host processor. One such prior art VPU is the IBM 9270 which communicates with its host processor through the vehicle of screen transactions. In specific, when the VPU receives an inquiry from a user, its associated processor requests a "screen" of data from a connected host processor, which screen includes the requested data.
A screen is a pixel image prepared by application software in the host processor in response to an inquiry. The screen is supplied to the VPU and its associated processor for the purpose of providing an answer in response to the user's inquiry.
In order to speed up a host processor's responses to user initiated inquiries, the prior art has employed the concept of "priming" applications running on a host processor. In U.S. Pat. No. 4,949,254 to Shorter, assigned to the same assignee as this application, a method is disclosed for allowing a host processor to establish within itself a number of virtual machines, each of which possesses a "primed" application. Shorter positions a "pool manager" within the host computer which acts to start a plurality of applications so that they are immediately ready when a request for access is received. This procedure avoids the log-in delays which occur when an application is initialized. After the applications are primed, each virtual machine within the host processor goes into an "idle" state and awaits a user to request the initiation of a session. Shorter also describes an algorithm for allocating virtual machines within the processor to assume that sufficient primed applications are available for the anticipated level of requests.
In order for the Shorter system to function, modifications must be made to the software operating system of the host processor to enable the establishment of the virtual machines. It is often desirable that a VPU operate in conjunction with a plurality of host processors which are not necessarily compatible at the operating system level. The Shorter system, in such an arrangement, requires that each host processor's operating system be altered. This is not only an expensive proposition, but it is often resisted by the owners of host processors for fear that any change to the operating system will alter other unrelated functions running on the host.
In addition to being able to access multiple hosts, a VPU should also be capable of handling multiple host sessions with different applications, in response to a single phone call. Likewise, a VPU should be able to map, via a virtual session, an incoming inquiry to any available host processor that contains a primed application capable of responding to the incoming request. Prior art describing various virtual session and machine arrangements can be found in the following U.S. Pat. No. 4,982,421 to Kirsch et al; U.S. Pat. No. 4,331,835 to Gueldner et al.; U.S. Pat. No. 5,012,466 to Buhrke et al; and U.S. Pat. No. 4,742,447 to Duvall et al.
Accordingly, it is an object of this invention to provide a voice processing interface system which enables access to a plurality of host processors, without requiring modification to the operating systems of those host processors.
It is an other object of this invention to provide a voice processing interface unit which enables a plurality of host sessions to be established in response to a single telephone inquiry.
It is still another object of this invention to provide a voice processing interface unit which employs screen interface communications with a plurality of host processors.

Voice processing interface unit employing virtual screen communications for accessing a plurality of primed applications

International Business Machines Corporation


A method and apparatus for filter spectrum deconvolution and reshaping include providing a filter output of a spectrum signal and determining the intensity and wavelength of the spectrum signal at each spectral peak. The filter output is characterized as an integral of convolution of a spectrum signal function and a filter function. Transformation are then performed on the filter output to deconvolve and remove the undesirable filter function and add a desirable filter function to reshape the output filter spectrum.

The fiber optics telecommunications area includes such technologies as fiber optical cables and fiber optical networks. Fiber optical networks carry a great variety of everyday information, such as conversations, data communications (e.g., fax messages), computer-to-computer data transfers, cable television, the Internet, and so forth. Such information signals are transported between cities as well as from place to place within cities. Due to the rapidly increasing amounts of such communication traffic, the increased capacity of fiber optical cables is more and more necessary, compared to the lower capacities of older metallic wire cables.
An optical fiber cable is typically composed of a bundle of individual optical fibers. One single optical fiber can carry thousands of data and communication signals on a single wavelength of light. That same single optical fiber can also carry multiple wavelengths of light, thus enabling it to carry many, many multiple optical signals at the same time. Each wavelength alone can carry data transferring at a rate over 10 Gbit/s.
To maintain communications over such optical networks, it is necessary to perform a variety of sensitive analyses, such as measuring the optical power, wavelength, and the optical signal-to-noise ratio of the optical signals at each of the wavelengths traveling through the optical fiber. Such analysis is carried out by an analytical tool called an optical spectrum analyzer ("OSA"). The OSA performs optical spectrum analysis (also referred to as "OSA"), which, as indicated, is the measurement of optical power as a function of wavelength.
OSA is typically performed by passing an optical signal to be analyzed through a tunable optical filter. "Tunable" means that the filter can be adjusted to resolve or pick out the individual components (wavelengths) of the optical signal.
Three basic types of filters are widely used to make OSAs: diffraction gratings, Fabry-Perot ("FP") filters, and Michelson interferometers. A tunable FP filter ("TFPF") has many advantages for OSA. Principal among these are its relatively simple design, small size, fast speed, ease of control, and its great sensitivity for distinguishing optical signals that are very closely spaced (i.e., signals that have frequencies or wavelengths that are very nearly the same.)
However, as compared with a diffraction grating with the same 3-dB bandwidth (which is defined as the magnitude of wavelength or frequency difference between the left and right spectral positions at 3-dB down from the peak position), the transmission profile of a TFPF has a relatively "broad skirt". The broad skirt means that beyond the 3-dB bandwidth ("BW") spectrum position, for example, the TFPF has a relatively slow decay of the rejection ratio to optical signals that are nearby in frequency or wavelength to the signals of interest. Such a broad skirt can be a considerable disadvantage for TFPFs when used to measure the optical-signal-to-noise-ratio ("OSNR") of signals of a wavelength division multiplexing ("WDM") system. This can allow signals from nearby, or adjacent, wavelengths to leak through and raise the "noise" floor artificially. The relatively broad skirt admits cross talk from adjacent WDM channels, thereby limiting the FP OSA's dynamic range ("DR") for OSNR measurements.
In contrast, with the same 3-dB BW the transmission profile of a diffraction grating has a much steeper skirt, but it is not so sensitive at distinguishing optical signals that are very closely spaced as compared with a TFPF. Theoretically, every optical filter admits cross talk from adjacent WDM channels. Due to its steeper skirt, a diffraction grating has much smaller cross talk than the FP filter with the same 3-dB BW.
Thus, a considerable need remains for methods and apparatus that can greatly enhance the DR for OSNR measurements of a FP filter-based OSA. In view of the ever-increasing need to save costs and improve efficiencies, it is more and more critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.

Method and apparatus for spectrum deconvultion and reshaping


The invention relates to a steerable catheter having a distal section with reduced variation in deflection path during deflection. The distal section of the catheter includes stripes of different material hardness along the length of the distal section affecting the directionality of catheter deflection upon the application of a deflection force like that applied by pull wires. The stripes result in preferential bending in a desired path with greater reproducibility.

a. Field of the Invention
The instant invention relates to catheters. In particular, the instant invention relates to a catheter with a steerable distal section having reduced variation in planarity during deflection.
b. Background Art
It is well-known that the pumping action of the heart is controlled by electrical stimulation of myocardial tissue. Stimulation of this tissue in various regions of the heart is controlled by a series of conduction pathways contained within the myocardial tissue.
Cardiac arrhythmias arise when the pattern of the heartbeat is changed by abnormal impulse initiation or conduction in the myocardial tissue. Such disturbances often arise from additional conduction pathways which are present within the heart either from a congenital developmental abnormality or an acquired abnormality which changes the structure of the cardiac tissue, such as a myocardial infarction.
One of the ways to treat such disturbances is to identify the conductive pathways and to sever part of this pathway by destroying these cells which make up a portion of the pathway. Traditionally, this has been done by either cutting the pathway surgically; freezing the tissue, thus destroying the cellular membranes; or by heating the cells, thus denaturing the cellular proteins. The resulting destruction of the cells eliminates their electrical conductivity, thus destroying, or ablating, a certain portion of the pathway. By eliminating a portion of the pathway, the pathway may no longer maintain the ability to conduct, and the arrhythmia ceases.
The success and advancement of current therapies is dependent upon the development and use of more precise localization techniques which allow accurate anatomical determination of abnormal conductive pathways and other arrythmogenic sites. Historically, the electrophysiologist has had to compromise between placing the catheter in the place of greatest clinical interest and areas that are anatomically accessible.
One area of advancement in improving localization techniques and accessing additional sites includes the use of curved and steerable catheters. Curved catheters offer improved maneuverability to specific, otherwise inaccessible sites by being shaped specifically to access a particular site. Although perhaps useful for some more accessible sites, the use of this type of catheter has limitations in reaching sites requiring active articulation during placement. Steerable catheters, which may also be pre-curved, proved additional advantages.
While steerability of catheters has improved, there is a need to eliminate significant variations in planarity during deflection of the distal tips of catheters. In accordance with this invention, a catheter is provided that addresses and potentially eliminates significant variation in planarity during catheter tip deflection. The invention also offers a catheter capable of a multitude of angular shaft deflection trajectories through a two or three dimensional range including a catheter that could initially be straight and, upon complete deflection, turn into a loop-shaped catheter. This invention would improve product reliability, consistency, and performance, as well as improve safety of electrophysiology ablation or diagnostic procedures.

True angular catheter shaft deflection apparatus

St. Jude Medical, Atrial Fibrillation Division, Inc.


A linear actuator (1) comprising a housing (6), a motor (2) comprising a stator with coils (4), a screw-nut system, and a rotor (5) axially and radially supported on the motor side by a bearing (11). The bearing comprises a ball (14) rigidly attached to the rotor, a cylindrical cavity (15) formed or positioned in the housing into which the ball (14) is inserted. A stop (17) is positioned in the cavity, supported in an axial direction of the rotor, against the ball (14) in essentially one point.

Linear actuators are used in many different applications. In the automotive field, linear actuators are used, inter alia, for positioning headlights in the horizontal and vertical planes, as described in publications U.S. Pat. No. 6,641,292, US 2005/0046291, and US 2005/0174796. The devices described in these publications include a stepping motor driving a screw-nut system for the linear displacement of a screw shaft. With the stepping motor, it is possible to displace and position the screw shaft rapidly, with few mechanical parts and by using a relatively simple control.
In the field of automobile headlight adjustment, it is important to have a high performance, reliable and dynamic screw-nut system, while using compact, lightweight and economical components. Components used in automobiles should moreover perform even under extreme environmental conditions, in particular for ranges of temperatures from −40° C. to 120° C.
In conventional actuators, the torque to be exerted by the rotor on the member to be displaced decreases when the temperature decreases, because of the increase of frictional forces in the bearings positioned between the rotor and the stator. This is due to the increase in the viscosity of the lubricants present in the bearings. Although certain lubricants have an acceptable viscosity at a very low temperature, the latter are either expensive or unacceptable for ecological reasons.
Another disadvantage of the aforementioned conventional actuators is the mechanical play that occurs when the displacement direction of the linear member is changed, this play being detrimental to the positioning accuracy of the headlights, as well as causing vibration and wear of the components.
US 2006/0108885 A1 discloses a motor with ball bearings, intended for consumer electronics applications. This motor is however not suitable for a linear actuator application in the automotive field because of the instability of the bearings. Indeed, the balls are housed in cavities of parts assembled in the housing of the motor, the balls being in abutment against an essentially spherical surface at the ends of the axis of the motor, but in a separable manner. In the case of vibration or shock, the interface between the balls and the ends of the axes may separate and even be fouled and worn, thereby leading not only to the possibility of radial vibration of the motor, but also to decentralization of the rotor. Moreover, the shape of the housing in which the balls are mounted, is sensitive to wear and positioning of the balls and requires accurate manufacturing and mounting tolerances.


The present disclosure discloses a multi-droplet sensing and actuation system, for use in a digital microfluidic chip operation wherein a linearly independent alternating current signal is applied to each discrete actuation electrode thus encoding the electrode's identity. The combined measured impedance signal from multiple channels is then processed to decode an impedance measurement for the volume between each discrete actuation electrode and its corresponding conductive counter electrode region, where the sensed impedance is inversely proportional to an amount of liquid within the volume.

Digital microfluidic chips are a technology for use in the micromanipulation of discrete droplets of fluid. This technology is employed as an alternative to conventional lab-on-a-chip systems. Conventional lab-on-a-chip systems typically use micro-scale mechanical devices (pumps, valves etc.) for the manipulation of the enclosed fluid. In contrast, in DMF systems, there are no moving parts; droplets are simply manipulated on a stationary array of electrodes covered by a dielectric layer. When one or more electrodes in the array is actuated (i.e., an electrical potential is applied to that/those electrode/s), the dielectric becomes locally polarized near the activated electrode(s). If one or more droplets are in the vicinity of the activated electrode(s), it is drawn over it/them, allowing direct manipulation of said droplets. This scheme allows for a number of unit droplet operations, including movement, merging, splitting, dispensing, and storing.
In the use of a DMF chip, there is a need to achieve fully automated control of said chips. Realizing this level of control requires strategies to detect and recover from the many possible errors that can occur during routine operation, including fabrication defects (e.g., shorts between electrodes, broken traces, dielectric breakdown), and surface modifications that occur during use (e.g., biofouling,1-3 ionization,4 or charge trapping5 caused by voltage saturation). These error-conditions can make it difficult or impossible to achieve any given operation that comprises moving a droplet to or from an affected electrode. In addition, some operations such as splitting and dispensing can be unpredictable even without defects or surface changes—i.e., the time required to complete these operations and the final volumes of daughter droplets are highly sensitive to the starting conditions (e.g., the volume and placement of the mother droplet,6 surface tension,7 etc.). Therefore, it is critical that digital microfluidics be paired with a detection system that is capable of sensing failure modes and also able to provide fast, dynamic control of splitting operations. Ideally, such a system would be simple, low-cost, and easy to integrate into existing systems.
The capability to sense droplet position and failure modes has been demonstrated with the open-source "DropBot" system.8 DropBot applies a common alternating current (AC) actuation signal to all actuated electrodes and measures the combined feedback signal from all actuated electrodes simultaneously and thus (unfortunately) has no means for isolating any single electrode. For DMF to be scalable, the detection system must be able to track the behavior of multiple droplets across many different electrodes in parallel. There are several functional approaches for implementing multi-electrode, parallel sensing. Gong and Kim9 described a simple method based on a ring oscillator circuit which they applied to droplet dispensing and splitting under proportional-integral-derivative (PID) control. They improved the precision of dispensed droplet volumes from +/−5% to +/−1% and demonstrated the ability to perform non-symmetric splitting. The major limitation to their method is that it only works with DC actuation, which has several drawbacks relative to AC operation, including an increased susceptibility to forces that resist droplet movement. Shin and Lee10 demonstrated a machine-vision approach for tracking a single droplet which could be extended to track multiple droplets in theory; however, such a system would be non-trivial to implement and operate. Image-based methods require extensive processing, high-speed cameras (if they are to capture droplet dynamics), controlled lighting, and they may be sensitive to the visual appearance of liquids (e.g., color). Furthermore, it is unlikely that an optically based system could explain a given observed problem—e.g., dielectric breakdown, shorts, and broken traces may appear the same to an optical sensor. One system that seems well suited for multi-electrode fault detection is the active, thin-film transistor (TFT) array-based device recently reported by Hadwen et al.11 These DMF devices consist of a 64×64 electrode array, each with its own integrated capacitive sensor that can perform measurements at a rate of 50 Hz.
This technology clearly has great potential, having achieved a scale (in terms of the number of addressable electrodes) that is orders of magnitude higher than any competing methods; however, fabricating these devices requires access to an industrial manufacturing line and therefore this technology is currently only available to employees of Sharp Corporation (Ichinomoto-cho, Tenri-shi, Japan) and their collaborators. Further, when produced at scale, it is not clear that TFT-based devices could ever be formed at appropriate cost for the single use (disposable) device requirements for many applications (e.g., applications involving biological samples are inherently limited by device lifetime). Thus, there is a critical need for an AC-compatible system for multi-droplet manipulation and sensing that is compatible with conventional, inexpensive devices.

Multiplexed droplet actuation and sensing in digital microfluidics