Showing papers on "Signal published in 2004"

The extraction of neural strategies from the surface EMG

Abstract: This brief review examines some of the methods used to infer central control strategies from surface electromyogram (EMG) recordings. Among the many uses of the surface EMG in studying the neural control of movement, the review critically evaluates only some of the applications. The focus is on the relations between global features of the surface EMG and the underlying physiological processes. Because direct measurements of motor unit activation are not available and many factors can influence the signal, these relations are frequently misinterpreted. These errors are compounded by the counterintuitive effects that some system parameters can have on the EMG signal. The phenomenon of crosstalk is used as an example of these problems. The review describes the limitations of techniques used to infer the level of muscle activation, the type of motor unit recruited, the upper limit of motor unit recruitment, the average discharge rate, and the degree of synchronization between motor units. Although the global surface EMG is a useful measure of muscle activation and assessment, there are limits to the information that can be extracted from this signal.

Functional Magnetic Resonance Imaging

Abstract: 1. An Introduction to fMRI 2. MRI Scanners 3. Basic Principles of MR Signal Generation 4. Basic Principles of MR Image Formation 5. MR Contrast Mechanisms and Acquisition Techniques 6. From Neuronal to Hemodynamic Activity 7. Properties of the fMRI BOLD Response 8. Signal, Noise, and Preprocessing of fMRI Data 9. Experimental Design 10. Statistical Analysis I: Hypothesis Testing 11. Statistical Analysis II: Data-Driven Approaches 12. Applications of fMRI 13. Converging Operations 14. Ethical Issues in fMRI Research

Signal processing apparatus and method

Abstract: A method and an apparatus to analyze two measured signals that are modeled as containing desired and undesired portions such as noise, FM and AM modulation. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, a transformation is used to evaluate a ratio of the two measured signals in order to find appropriate coefficients. The measured signals are then fed into a signal scrubber which uses the coefficients to remove the unwanted portions. The signal scrubbing is performed in either the time domain or in the frequency domain. The method and apparatus are particularly advantageous to blood oximetry and pulserate measurements. In another embodiment, an estimate of the pulserate is obtained by applying a set of rules to a spectral transform of the scrubbed signal. In another embodiment, an estimate of the pulserate is obtained by transforming the scrubbed signal from a first spectral domain into a second spectral domain. The pulserate is found by identifying the largest spectral peak in the second spectral domain.

Digital wireless position sensor

Abstract: A method is provided for tracking an object, including positioning a radio frequency (RF) driver to radiate an RF driving field toward the object, and fixing to the object a wireless transponder that includes a power coil and at least one sensor coil. The method also includes receiving the RF driving field using the power coil and storing electrical energy derived therefrom. A plurality of field generators are driven to generate electromagnetic fields at respective frequencies in a vicinity of the object that induce a voltage drop across the at least one sensor coil. A digital output signal is generated at the wireless transponder indicative of the voltage drop across the sensor coil, and the generation of the digital output signal is powered using the stored electrical energy. The digital output signal is transmitted from the wireless transponder using the power coil, and the transmission of the digital output signal is powered using the stored electrical energy. The digital output signal is received and processed to determine coordinates of the object.

Method and arrangement for control of direct current motor

Abstract: The present invention relates to a method for control of a direct current motor (30) in one or several fan units (43, 20, 21), each comprising a fan, which method comprises: generation of a control signal from a first control unit (22) which is external in relation to the said fan unit (43, 20, 21); transmission of the said control signal to the said fan unit (43, 20, 21); reception of the transmitted control signal in the said fan unit (43, 20, 21); interpretation of the said control signal in a second control unit (26) which is arranged in association with the said fan unit (43, 20, 21); and generation, in the said second control unit (26), of a supply signal for the said direct current motor (30), on the basis of the control signal generated by the first control unit (22) and received in the fan unit and on the basis of a supply voltage. According to the invention, the method comprises transmission of the control signal together with the supply voltage over a shared communication link (44), with the control signal being superposed on the supply voltage. The invention also relates to an arrangement for such control. By means of the invention, improved control is obtained of a motor that can be utilized in a ventilated seat in a vehicle.

Electronic endoscope system

Abstract: An electronic endoscope system includes an image pickup device provided at a distal end of an insertion portion; an image signal processing device; a main light source; an auxiliary light source which emits less amount of light than the light emitted from the main light source; and a light guide member which guides illumination light emitted from one of the main light source and the auxiliary light source to the distal end of the insertion portion to thereby emit the illumination light from the distal end. When the auxiliary light source emits the illumination light instead of the main light source, the image signal processing device sets the gain of the signal output from the image pickup device to a value higher than the gain of the signal when the main light source emits the illumination light, in order to process the image signal.

Coherent detection method using DSP for demodulation of signal and subsequent equalization of propagation impairments

Abstract: A new approach to coherent detection is demonstrated which achieves the same high sensitivity as homodyne detection but without the need to phase lock the local oscillator laser. In addition, 1470 ps/nm of chromatic dispersion is compensated with zero net penalty by electronic domain equalization, a result which has not been achieved before because zero-penalty equalization is not possible after direct detection. The method proposes the use of high-speed digital signal processing technology, and the experimental results are obtained using burst-mode sampling followed by offline signal processing.

Dynamic clustering for acoustic target tracking in wireless sensor networks : Special section on mission-oriented sensor networks

Abstract: In the paper, we devise and evaluate a fully decentralized, light-weight, dynamic clustering algorithm for target tracking. Instead of assuming the same role for all the sensors, we envision a hierarchical sensor network that is composed of 1) a static backbone of sparsely placed high-capability sensors which will assume the role of a cluster head (CH) upon triggered by certain signal events and 2) moderately to densely populated low-end sensors whose function is to provide sensor information to CHs upon request. A cluster is formed and a CH becomes active, when the acoustic signal strength detected by the CH exceeds a predetermined threshold. The active CH then broadcasts an information solicitation packet, asking sensors in its vicinity to join the cluster and provide their sensing information. We address and devise solution approaches (with the use of Voronoi diagram) to realize dynamic clustering: (I1) how CHs cooperate with one another to ensure that only one CH (preferably the CH that is closest to the target) is active with high probability, (12) when the active CH solicits for sensor information, instead of having all the sensors in its vicinity reply, only a sufficient number of sensors respond with nonredundant, essential information to determine the target location, and (13) both the packets that sensors send to their CHs and packets that CHs report to subscribers do not incur significant collision. Through both probabilistic analysis and ns-2 simulation, we show with the use of Voronoi diagram, the CH that is usually closest to the target is (implicitly) selected as the leader and that the proposed dynamic clustering algorithm effectively eliminates contention among sensors and renders more accurate estimates of target locations as a result of better quality data collected and less collision incurred.

Detection and monitoring of hidden fatigue crack growth using a built-in piezoelectric sensor/actuator network: I. Diagnostics

Abstract: A piezoelectric based built-in diagnostic technique has been developed for monitoring fatigue crack growth in metallic structures. The technique uses diagnostic signals, generated from nearby piezoelectric actuators built into the structures, to detect crack growth. It consists of three major components: diagnostic signal generation, signal processing and damage interpretation. In diagnostic signal generation, appropriate ultrasonic guided Lamb waves were selected for actuators to maximize receiving sensor measurements. In signal processing, methods were developed to select an individual mode for damage detection and maximize signal to noise ratio in recorded sensor signals. Finally, in damage interpretation, a physics based damage index was developed relating sensor measurements to crack growth size. Fatigue tests were performed on laboratory coupons with a notch to verify the proposed technique. The damage index measured from built-in piezoceramics on the coupons showed a good correlation with the actual fatigue crack growth obtained from visual inspection. Furthermore, parametric studies were also performed to characterize the sensitivity of sensor/actuator location for the proposed technique.

Time domain radio transmission system

Abstract: A time domain communications system wherein a broadband of time-spaced signals, essentially monocycle-like signals, are derived from applying stepped-in-amplitude signals to a broadband antenna, in this case, a reverse bicone antenna. When received, the thus transmitted signals are multiplied by a D.C. replica of each transmitted signal, and thereafter, they are, successively, short time and long time integrated to achieve detection.

Ink jet printer

Abstract: An ink jet printer has: a vibration detection section to receive ink jetted from the nozzles and output a detection signal having an amplitude corresponding to a vibration generated when the ink lands; a sampling section to sample an amplitude value of the detection signal by a predetermined sampling clock signal; a storing section to store an amplitude value data of the detection signal sampled by the sampling section; a judging section to judge a jet failure of the nozzles based on the amplitude value data of the detection signal in the storing section; and a control section to control to jet the ink continuously a plurality of times with a jet drive cycle which is set by multiplying a standard drive waveform time of an ink jet signal from the nozzles by an odd number not less than five when detecting a jet failure of the nozzles.

Methods and systems for encoding and protecting data using digital signature and watermarking techniques

Abstract: Systems and methods are provided for protecting and managing electronic data signals that are registered in accordance with a predefined encoding scheme, while allowing access to unregistered data signals. In one embodiment a relatively hard-to-remove, easy-to-detect, strong watermark is inserted in a data signal. The data signal is divided into a sequence of blocks, and a digital signature for each block is embedded in the signal via a watermark. The data signal is then stored and distributed on, e.g., a compact disc, a DVD, or the like. When a user attempts to access or use a portion of the data signal, the signal is checked for the presence of a watermark containing the digital signature for the desired portion of the signal. If the watermark is found, the digital signature is extracted and used to verify the authenticity of the desired portion of the signal. If the signature-containing watermark is not found, the signal is checked for the presence of the strong watermark. If the strong watermark is found, further use of the signal is inhibited, as the presence of the strong watermark, in combination with the absence or corruption of the signature-containing watermark, provides evidence that the signal has been improperly modified. If, on the other hand, the strong mark is not found, further use of the data signal can be allowed, as the absence of the strong mark indicates that the data signal was never registered with the signature-containing watermark.

Implantable, retrievable, thrombus minimizing sensors

Abstract: A sensor is disclosed, for implantation within a blood vessel to monitor a substance in or property of blood. In one embodiment, the sensor is retrievable. In another embodiment, the sensor has a layer that minimizes the formation of thrombus. A signal representative of the substance in or property of blood is transmitted to an external receiver. In another embodiment, the sensor detects nitric oxide or a nitric oxide metabolite and can be implanted for a period of hours, days, weeks or years. Methods are also disclosed.

Portable motion detector and alarm system and method

Abstract: A portable security alarm system including a movement detecting and signal transmitting member for mounting on or proximate to the object whose movement is to be detected, a signal receiving and alarm generating member for receiving a signal from the movement detecting and signal transmitting member and producing a security response, a remote control for actuating and deactuating the signal receiving and alarm generating member, an environmental monitoring member for sensing an environmental condition and providing a signal to the signal receiving and alarm generating member, a visual information gathering member for gathering visual information and providing a signal to the signal receiving and alarm generating member, an audio output member for receiving a signal from the signal receiving and alarm generating member and generating an audio output, and components for delivering a security notification to remote recipients. A security network that includes the alarm system is also disclosed. An inertial sensor for alarm system or for activating or deactivating a device is additionally disclosed.

Electronic security system for monitoring and recording activity and data relating to cargo

Abstract: A tracking system for identifying contents of a container includes an electromagnetic identification apparatus that provides an electromagnetic signal indicative of a container content data set; a writer for use in encoding the container signal onto the apparatus; a controller for receiving the encoded signal and for storing the signal in a master database storage apparatus; and a reader configured outside the container for communicating with the electromagnetic identification apparatus and for receiving the encoded signal therefrom and corresponding to the container content data signal set. A system for tracking items in an assembly includes an apparatus for receiving electromagnetic identification tag signals; an apparatus for creating a first tier aggregate signature; an apparatus for storing the signature in a master database; and an apparatus for receiving modifying command signals for creating a second tier aggregate signature corresponding to a modified set of electromagnetic identification tags in an augmented assembly.

Fuel level indicator for combustion tools

Abstract: A combustion tool employing a replaceable pressurized fuel cell includes a fuel condition monitor system for monitoring and indicating fuel cell fuel condition. The fuel condition monitor system includes a fuel condition monitor for monitoring at least one of fuel cell pressure and fuel flow from the fuel cell, a control unit connected to the monitor for receiving fuel condition data sensed by the monitor, comparing the sensed data with preset values and determining fuel level in the fuel cell based on the determinations, a metering valve connected to the control unit, providing the exact amount of fuel based upon fuel cell condition, and an indicator connected to the control unit for providing an indication of fuel level. A method of monitoring and indicating combustion tool fuel cell condition includes providing a preset series of fuel cell condition values, monitoring fuel cell condition, obtaining fuel cell condition data, comparing the monitored data with preset values and determining whether there is sufficient fuel and providing a signal to an indicator.

Systems and methods for color changing device and enclosure

Abstract: A color-changing device which includes an enclosure at least a portion of which is material which is desired to change color. There is also included an illumination device, such as an LED or collection of LEDs which can illuminate the material. There can also be included a controller which can take some form of input, such as from a network, or a sensor, and can convert that input into a signal to control the illumination. There is also included a method for performing such color change.

Distance image sensor

Abstract: A distance image sensor for removing the background light and improving the charge transfer efficiency in a device for measuring the distance to an object by measuring the time-of-flight of the light. In a distance image sensor for determining the signals of two charge storage nodes which depend on the delay time of the modulated light, a signal by the background light is received from the third charge storage node or the two charge storage nodes in a period when the modulated light does not exist, and is subtracted from the signal which depends on the delay time of the two charge storage nodes, so as to remove the influence of the background. Also by using a buried diode as a photo-detector, and using an MOS gate as gate means, the charge transfer efficiency improves. The charge transfer efficiency is also improved by using a negative feedback amplifier where a capacitor is disposed between the input and output.

System and method for closed-loop neural stimulation

Abstract: Various aspects of the present subject matter provide a device. In various embodiments, the device comprises a port adapted to connect a lead, a pulse generator connected to the port and adapted to provide a neural stimulation signal to the lead, and a signal processing module connected to the port and adapted to receive and process a nerve traffic signal from the lead into a signal indicative of the nerve traffic. The device includes a controller connected to the pulse generator and the signal processing module. The controller is adapted to implement a stimulation protocol to provide the neural stimulation signal with desired neural stimulation parameters based on the signal indicative of the nerve traffic. Other aspects are provided herein.

Motion compatible sensor for non-invasive optical blood analysis

Abstract: A non-invasive optical sensor which uses the motion signal to calculate the physiological characteristic being measured. For pulse oximetry, a least squares or a ratio-of-ratios technique can be applied to the motion signal itself. This is made possible by selecting a site on the patient where variations in motion produce signals of two wavelengths which are sufficiently correlated. In particular, it has been determined that a sensor placed on a nail, in particular a thumbnail, exhibits the characteristics of having the red and infrared signals correlated when used for pulse oximetry, and the resulting signals correlate to arterial oxygen saturation.

Wavelet-based active sensing for delamination detection in composite structures

Abstract: In this paper a signal processing technique is developed to detect delamination on composite structures. In particular, a wavelet-based signal processing technique is developed and combined with an active sensing system to produce a near-real-time, online monitoring system for composite structures. A layer of piezoelectric patches is used to generate an input signal with a specific wavelet waveform and to measure response signals. Then, the response signals are processed by a wavelet transform to extract damage-sensitive features from the original signals. The applicability of the proposed method to delamination identification has been demonstrated by experimental studies of a composite plate under varying temperature and boundary conditions.

Apparatus and method for bioelectric stimulation, healing acceleration, pain relief, or pathogen devitalization

Abstract: An method and method for generating an electrical signal for use in biomedical applications, including two timing-interval generators, each optionally driving a multistep sequencer; analog, digital or hybrid means for combining the resulting timed signals into a complex electrical signal; optional filtering means for blocking direct current, removing selected frequency components from the resulting signal, and/or providing voltage step-up if needed; and conductive means for coupling the resulting signal to a human or animal body, food, beverage or other liquid, cell or tissue culture, or pharmaceutical material, in order to relieve pain, stimulate healing or growth, enhance the production of specific biochemicals, or devitalize selected types of organisms.

System and method for activation of portable and mobile media player devices for wireless lan services

Abstract: A system and a method for activation of portable and mobile media player devices for wireless LAN services have been disclosed. In one embodiment, the system includes a server computer, a wireless transmitter to transmit a signal, and a portable device comprising a wireless receiver to receive the signal and a wireless transceiver to transition from a first state to a second state to perform content synchronization with the server computer in response to the signal, wherein the wireless transceiver consumes less power in the first state than in the second state. Other embodiments have been claimed and described.

Adaptive and interactive scene illumination

Abstract: Apparatus for adaptively and interactively lighting a scene includes a digital light projector that includes a light emitter and a digital light processor optically coupled to the emitter such that the emitter light is projected onto respective individual fields of view of a field of regard illuminating the scene in accordance with a projector control signal. A camera adjacent to the projector is operative to detect light reflected or projected from the illuminated scene and generate a signal corresponding to the detected light. A signal processor coupled to the projector and the camera is operative to receive the camera signal, process the received signal into a light projector control signal in accordance with an associated set of instructions, and apply the control signal to the light projector such that the light projected onto the respective individual fields of view of the illuminating array is controlled in accordance with the instructions.

Generation of electrical energy for portable devices: Comparative study of an electromagnetic and a piezoelectric system

Abstract: This paper presents the comparative study of two different electromechanical systems, in order to conceive autonomous portable generators capable of harvesting human mechanical energy. The first one is an electromagnetic system, made of a magnet in translation within a coil. The second one is a piezoelectric system, which is a PZT ceramic bar, polarised longitudinally, embedded at one end and constrained at the other end. The analytical models described in this paper present a high similarity and a duality in signal levels, adapted load and optimal working frequency, the two latters corresponding to the maximal electrical power generated.

Nonlinear analysis of EEG signals at different mental states.

Abstract: Background: The EEG (Electroencephalogram) is a representative signal containing information about the condition of the brain. The shape of the wave may contain useful information about the state of the brain. However, the human observer can not directly monitor these subtle details. Besides, since bio-signals are highly subjective, the symptoms may appear at random in the time scale. Therefore, the EEG signal parameters, extracted and analyzed using computers, are highly useful in diagnostics. This work discusses the effect on the EEG signal due to music and reflexological stimulation. Methods: In this work, nonlinear parameters like Correlation Dimension (CD), Largest Lyapunov Exponent (LLE), Hurst Exponent (H) and Approximate Entropy (ApEn) are evaluated from the EEG signals under different mental states. Results: The results obtained show that EEG to become less complex relative to the normal state with a confidence level of more than 85% due to stimulation. Conclusions: It is found that the measures are significantly lower when the subjects are under sound or reflexologic stimulation as compared to the normal state. The dimension increases with the degree of the cognitive activity. This suggests that when the subjects are under sound or reflexologic stimuli, the number of parallel functional processes active in the brain is less and the brain goes to a more relaxed state

Touch detection for a digitizer

Abstract: A detector for providing position detection of objects over a sensor with a first and second set of conductor lines forming a grid with a plurality of junctions there between at which the conductor lines do not contact, includes a signal generator providing a signal to at least one conductor line of the first set of conductor lines, and circuitry detecting output arising from one or both of an electromagnetic stylus and one or more fingers when present. The output arising from each of the one or more fingers is detected from at least one conductor line of the second set of conductor lines in response to the signal provided to the at least one conductor line of the first set of conductor lines. The circuitry detects positions of one or both the electromagnetic stylus and each of the one or more fingers when present responsive to the output detected.

Semiconductor memory device

Abstract: PROBLEM TO BE SOLVED: To repeatedly perform defectives relieving for the same address without increasing a load of a data system SOLUTION: A semiconductor memory device is provided with a memory cell array 1, a plurality of redundant cell array 3, a plurality of redundant address program circuits 20 outputting a redundant selecting signal for selecting a corresponding redundant cell array 3, an address selecting circuit 15 selecting an address of the memory cell array 1 corresponding to an address selecting signal when a redundant selecting signal is not outputted from any of the redundant address program circuits 20, and redundant cell array selecting means 30, 31 selecting only a redundant cell array 3 having the highest priority when priority is given to the plurality of redundant cell arrays 3 and a redundant selecting signal for selecting redundant cell arrays 3 of two or more for the same address out of the plurality of redundant address program circuits 20 is received COPYRIGHT: (C)2004,JPO&NCIPI