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System Theory, 2002. Proceedings of the Thirty-Fourth Southeastern Symposium on

Date 19-19 March 2002

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  • Proceedings of the Thirty-Fourth Southeastern Symposium on System Theory (Cat. No.02EX540)

    Publication Year: 2002
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    Freely Available from IEEE
  • Author's index

    Publication Year: 2002 , Page(s): 491 - 493
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    Freely Available from IEEE
  • Interpolation and gradient estimation of images using the discrete cosine transform

    Publication Year: 2002 , Page(s): 167 - 170
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (891 KB) |  | HTML iconHTML  

    A signal can be represented completely by the weighted sum of any complete orthonormal set of basis functions. The discrete cosine transform (DCT) has long been used in image processing because, short of the Karhunen-Loeve transform, it typically provides the highest amount of compression of the image transforms commonly used. In addition to its use in compression, the DCT may also be used as a set of basis functions. We demonstrate how the DCT basis functions may be used to interpolate an image and provide a gradient estimate at interpolated points. View full abstract»

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  • Electronic scanning of sonar beam from a phased array of acoustic transducers controlled through programmable digital delay lines

    Publication Year: 2002 , Page(s): 366 - 370
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (369 KB) |  | HTML iconHTML  

    Electronic scanning of the beam with phased arrays is faster compared to rotating antennas, and with the phased arrays kept stationery, the beam could be shifted in a manner as desired by the system by controlling the phases. By and large, delay lines are used for producing the necessary phase shifts for the array elements. The use of digital delay lines improve further the rate of scanning and avoids the installation of bulky acoustic delay lines whose performance characteristics are affected by the environment in which it is operated. The recently reported digital delay line has simplicity in controlling the delay lengths from a single analog source. This project employs that digital delay line for scanning the beam in linear directions and also for scanning a sector like raster scanning. The implementations and performance characteristics are reported. View full abstract»

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  • The costs and benefits of using complex 2-D Gabor filters in a filter-based fingerprint-matching system

    Publication Year: 2002 , Page(s): 171 - 175
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (549 KB) |  | HTML iconHTML  

    In this paper, we investigate the utility of complex, 2-D Gabor filter for a fingerprint matching system. Previous approaches have used an even symmetric 2-D Gabor filter to perform fingerprint feature extraction processing. Several processing methods using a complex filter are explored and compared to the even-symmetric case. Conclusions are drawn based upon both the results of using a complex filter and the added computational costs of doing so. View full abstract»

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  • Comparison of performance of neural network controller and DAC based adaptive controller for a robot arm

    Publication Year: 2002 , Page(s): 371 - 375
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB) |  | HTML iconHTML  

    Disturbances in most of the systems makes their performance mitigating. So in order to comply with the situation, a controller should be developed which could adapt to these disturbances and get the best out of the system. This paper gives a comparison of the results of a disturbance accommodating control based adaptive controller (or better known as linear adaptive controller) and a neural networks model reference controller. The aim of the control algorithm is to control the movement of a robot arm, which is freely suspended. The input to the plant is the torque from the controller. The input to the controller is the difference between the reference angle and the output "angle" from the plant. In comparison, the results prove that the linear adaptive controller adapted in a much wider sense to the disturbances and changes in the system than the neural network model reference controller. The simulation figures support the results that were put forth. View full abstract»

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  • Genetic algorithms-based parameter optimization of a non-destructive damage detection method

    Publication Year: 2002 , Page(s): 152 - 156
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (457 KB) |  | HTML iconHTML  

    The method of strain energy mode shapes allows the determination of changes in structural integrity from changes in the vibrational response of a structure. The modified method presented does not require knowledge of the undamaged state of the structure. Genetic algorithms (GA) are applied to produce a sufficiently optimized amplitude characteristic of a filter used to extract damage information from strain energy mode shapes. Finite element modeling has been used to produce a training data set with the known location of damages. The amplitude characteristic of the filter has been encoded as a genetic string where the pass coefficient for each harmonic of its discrete Fourier transform representation is a number between zero and one in 8-bit Gray code. The genetic optimization has been performed based on the minimization of the signal-to-distortion ratio. The amplitude characteristic of the filter was not limited to any specific configuration, i.e. either low-or high-pass or specific cut-off frequencies. The results obtained from the GA confirmed the theoretical predictions and allowed improvement in the method's sensitivity to damages of lower magnitude. View full abstract»

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  • An accelerometer-based physical rehabilitation system

    Publication Year: 2002 , Page(s): 57 - 60
    Cited by:  Papers (3)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (625 KB) |  | HTML iconHTML  

    This paper presents a portable physical rehabilitation monitoring system based on a personal network of intelligent sensors. Rehabilitation is traditionally carried out in hospitals under supervision of qualified personnel. However, significantly better results could be achieved using out-of-hospital portable monitoring to allow patients computer-assisted rehabilitation in their homes. The new generation of personal digital assistants (PDA), such as Compaq iPAQ, offers large processing power, decent graphical user interface, and compact flash based secondary memory. Therefore, they are perfectly suited for portable monitoring units. Individual sensors are positioned on limbs to analyze movements using 2-axis MEMS accelerometers. The system monitors periods and forces of individual sensors, visualizing relevant physiological data in real-time on PDA, and archiving progress data on compact flash. A specialist supervises current advance and sets new optimum rehabilitation modes, thresholds for forces, step periods, etc. The system generates real-time warnings when predefined thresholds have been exceeded. We are developing a system for hip and knee replacement rehabilitation, as well as general physical rehabilitation. Other possible applications of our system include rehabilitation of stroke and heart attack patients. View full abstract»

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  • Adaptivity on an OFDM fixed wireless access system

    Publication Year: 2002 , Page(s): 458 - 462
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (588 KB) |  | HTML iconHTML  

    A special characteristic of multicarrier modulation techniques such as OFDM is that they can assign different modulation schemes to each subcarrier according to a reception quality measurement such as the signal-to-noise ratio (SNR) on a subcarrier. This process allocates different bits to subcarriers and is further known at the literature as bit loading. In the paper, a bit-loading algorithm has been modified to take into account the presence of variable location pilots in each OFDM symbol. The target of this enhancement is to measure the system performance increase and the bandwidth efficiency improvement obtained. The study has been done for a broadband fixed wireless system. View full abstract»

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  • Inductive load current harmonic injection

    Publication Year: 2002 , Page(s): 307 - 310
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (411 KB) |  | HTML iconHTML  

    Induction motor audible noise can be related to the frequency content present in the stator winding currents. These currents produce time varying air gap fluxes which in turn produce exciting forces resulting in vibrations in the mechanical structure. By adding harmonics into the winding currents, additional frequencies can be added to the air gap flux and audible noise. If the additional frequencies can be made to mask the switching related noise components, a motor drive combination will be less annoying than an unmasked combination. This paper shows results obtained by using a wait-hop strategy to extend the range of frequencies obtainable by using a look-up table, and a multiple index implementation for signal construction. View full abstract»

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  • Analysis of a linear variable reluctance motor with magnetically coupled phases

    Publication Year: 2002 , Page(s): 219 - 223
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (571 KB) |  | HTML iconHTML  

    This paper deals with the magnetic modeling of a type of linear variable reluctance motor. The motor under study is a three-phase motor that exhibits strong magnetic coupling between its phases. Two modeling techniques are used: the magnetic circuit analysis is emphasized due to its simplicity and computational efficiency; and the finite element analysis is used primarily to provide accurate benchmark data for comparison. Qualitative agreement between the two modeling techniques is demonstrated. View full abstract»

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  • Communication delays in wide area measurement systems

    Publication Year: 2002 , Page(s): 118 - 122
    Cited by:  Papers (54)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (577 KB) |  | HTML iconHTML  

    This paper provides a tutorial introduction to phasor measurement units (PMU) when applied in a power system environment, provides an overview of communication alternatives for wide area measurement systems (WAMS), and computes the delay budget for each type of communication link. The goal of this study is to provide data regarding the communication delay that can be incorporated into the analysis and simulation of WAMS. View full abstract»

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  • Increasing the efficiency of the use of wavelet-like finite element basis functions

    Publication Year: 2002 , Page(s): 142 - 146
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB) |  | HTML iconHTML  

    In this paper, some of the advantages and disadvantages of the use of wavelet-like basis functions are discussed. Two modifications for mitigating some of the disadvantages are considered. Numerical results obtained using these modifications are presented. View full abstract»

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  • Multi-class support vector machine classifier applied to hyper-spectral data

    Publication Year: 2002 , Page(s): 271 - 274
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (481 KB) |  | HTML iconHTML  

    The availability of sufficient training data is a continuing challenge for most real world classification problems. This is especially true for hyperspectral processing since there are a very limited number of high quality hyperspectral sensors. In general, discrimination techniques require a large amount of training data in order to produce reliable probability distributions. Unfortunately, there is usually not a statistically significant amount of real data to adequately describe the various object classes. Given this limitation, we propose a novel algorithm approach based on support vector machines (SVM). Support vector machines are a type of learning machine based on statistical learning theory developed by Vapnik (1982, 1995). SVM overcome the limitations of traditional discrimination approaches that seek to minimize risk based solely on training data. SVM accomplishes this through its ability to "generalize errors" which has been shown to be more robust than traditional risk approaches. This capability to generalize makes SVM ideal for real world problems. This paper will present a support vector machine algorithm applied to a multiclass hyperspectral scenario using data from the AVIRIS sensor. View full abstract»

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  • Improved radar revisit time control to observe ballistic missile mode transitions

    Publication Year: 2002 , Page(s): 349 - 353
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB) |  | HTML iconHTML  

    For systems that can be modeled using multiple models and Markovian switching probabilities, an interacting multiple model (IMM) estimator is a good approach to state estimation and mode detection. For good mode detection, it is desirable to maintain the mode-probability set so that one of the probabilities is near unity. For radar tracking a ballistic missile, the mode probability is dependent on the so-called revisit time defined as the elapsed time between each measurement. It is shown that selecting a revisit time that controls the value of a mode-switching coefficient yields acceptable performance in terms of both the mode probability and tracking error. The potential robustness of the method to tracking conditions is demonstrated through a mid-fidelity, physics-based radar simulation using targets that differ in both type and radar-to-target geometry. The results show that the proposed adaptive-revisit method performs well during boost, boost-to-coast transition, and ballistic coast, as measured by tracking error when compared to both a constant revisit interval and an ad-hoc, altitude-based revisit schedule. View full abstract»

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  • Cooperative visual team working and target tracking of mobile robots

    Publication Year: 2002 , Page(s): 376 - 380
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (857 KB) |  | HTML iconHTML  

    The problem of visual coordination and target tracking mobile robots cooperating in an unstructured environment is addressed. In this paper, we consider a team of semi-autonomous robots controlled by a remote supervisory control system. We present an algorithm for visual position tracking of individual cooperative robots within their working environment. Initially, we present a technique suitable for visual servoing of a robot toward its landmark targets. Then, we present an image-processing technique that utilizes images from a remote surveillance camera for localization of the robots within the operational environment. In this algorithm, the surveillance camera can be either stationary or mobile. The supervisor control system keeps tracks of relative locations of individual robots and utilizes relative coordinates information of the robots to coordinate their cooperative activities. We present some results of this research effort that illustrates the effectiveness of the proposed algorithms for cooperative robotic systems visual team working and target tracking. View full abstract»

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  • Virtual attendance in real engineering labs

    Publication Year: 2002 , Page(s): 61 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (481 KB) |  | HTML iconHTML  

    Engineering laboratory equipment at UTC has been made available for users via the World Wide Web. Users can conduct systems lab experiments from remote sites, anytime day-or-night, any day of the week. This paper describes the development of these systems, the current situation and future plans. View full abstract»

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  • Performance of noise canceller using adjusted step size LMS algorithm

    Publication Year: 2002 , Page(s): 248 - 250
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    An adjusted step size LMS (least mean squares) algorithm is proposed for possible improvements in the performance of adaptive FIR filters in nonstationary environments. Nonstationary signals means that the statistical properties of the noise changes in time such as the high frequency channel time variations. In the paper, an adaptive noise canceller is proposed which is based on signal to noise ratio number to adjust the step size. In addition the same algorithm can be used for line enhancement and tracking high frequency channels which is used to provide high data rate in communications. View full abstract»

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  • Evaluation of the measurement update interval for an adaptive radar scheduler

    Publication Year: 2002 , Page(s): 354 - 357
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (359 KB) |  | HTML iconHTML  

    This paper presents a technique for determining the radar scheduler update interval. Given the system state-variable model and its statistical data, a matrix expression for the general order predictor error covariance matrix is derived. A cost function of this covariance matrix is solved to regulate the radar's Kalman filter measurement update intervals. Simulation experiments are performed and results presented. View full abstract»

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  • Wireless distributed data acquisition system

    Publication Year: 2002 , Page(s): 463 - 466
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (521 KB) |  | HTML iconHTML  

    Distributed data acquisition requires a flexible system organization, particularly when individual devices are mobile. The utility companies have been developing similar systems for several years now. In the case of medical devices, a mobile patient monitoring device would allow patients to leave the hospital and engage in normal activity, uploading physiological data only periodically. The wireless distributed data acquisition system presented in this paper is developed for mobile client devices, and mobile gateways. Each client device has some form of secondary storage, such as flash memory, to store the data that it acquired while it is not transmitting the data to the gateway device. The system maintains a database to keep track of the data acquired with respect to the data that it transmits to the gateway device. Each client device is uniquely identified. The gateway device polls client devices within its reach to transfer the client records to database. Gateways use existing communication infrastructure, such as cell phone link, and local connection to upload data to the server. We present the system developed around low-power microcontroller Texas Instruments MSP430F149, using standard 900 MHz wireless link, Smart Media Card as a secondary memory, and a portable PDA based gateway. View full abstract»

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  • Supervised control of cooperative multi-agent robotic vehicles

    Publication Year: 2002 , Page(s): 386 - 390
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (719 KB) |  | HTML iconHTML  

    In this paper, we address some of technical challenges associated with supervised tactical mobility behaviors modeling and control of a group of cooperative multi-agent robotic vehicles. Cooperative task planning of robotic systems is a dynamic and complex problem and very challenging. The challenge comes from many avenues including task decomposition, assignment, resource allocation, and task execution and monitoring. Furthermore, the behavior-based control system requires a deliberative and reactive task planning capability for execution of cooperative tasks of mobile robots as well as adequate adaptability to learn new cooperative schemes to improve system performance in over-time. Another challenge of this problem is associated with sensory data gathering, distributed data processing, centralized/decentralized data fusion, and intelligent world perception modeling and comprehension of cooperative mobile robots. We propose a multilayered supervisory control architecture for coordinated task planning of a group of multi-agent robots. The supervisory controller allows control of robotic vehicles in either teleoperation, semi-autonomous, and/or autonomous modes. View full abstract»

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  • A low power intelligent video-processing sensor

    Publication Year: 2002 , Page(s): 176 - 178
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (409 KB) |  | HTML iconHTML  

    Power efficient video signal processing is very important in the fields of intelligent robots, self guided vehicles and security systems. We have developed a low power intelligent video imaging sensor (IVIS), based on the Kodak CMOS Digital Image Sensor KAC-0311 with a resolution of 640×480 pixels. The image sensor is controlled by the low power Texas Instruments MSP430F149 microcontroller. The IVIS sensor can be integrated into distributed or hierarchical systems using a wireless interface or a standard RS-232 serial link. The sensor has a low typical power consumption and a processing power of 8 MIPS. This paper presents prototype development and basic features of the IVIS video processing sensor. View full abstract»

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  • A survey paper on independent component analysis

    Publication Year: 2002 , Page(s): 239 - 242
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (404 KB) |  | HTML iconHTML  

    Independent component analysis (ICA) is a statistical and computational technique for revealing hidden or underlying factors in data. The independent components or sources can be found using ICA provided that all components are independent and non-Gaussian. View full abstract»

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  • Prototype design of a personal static VAr compensator

    Publication Year: 2002 , Page(s): 311 - 315
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (505 KB) |  | HTML iconHTML  

    A prototype personal static VAr compensator (PSVC) has been designed and implemented for load power factor correction for both residential and commercial applications. The PSVC demonstrates the two key benefits of power factor correction, which include decreased power costs and increased system capacity. The PSVC also demonstrates conventional static VAr compensator (SVC) principles that are routinely applied by power utilities. The designed PSVC prototype consists of two main branches-a TSC (thyristor switched capacitor) branch and a TCR (thyristor controlled reactor) branch. A microcontroller is responsible for calculating the displacement power factor and for executing the fuzzy logic control scheme for the two branches. The PSVC is being evaluated using an inductive load and an AC motor. Test results are presented in this paper. View full abstract»

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  • Some implementation results and system effects of power electronic speed control of three-phase AC motors in closed-loop operation

    Publication Year: 2002 , Page(s): 224 - 228
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (401 KB) |  | HTML iconHTML  

    Certain properties of electronic speed control of three-phase AC motors are described, including some properties that can be modified by the user in the field. Emphasis is placed on the closed-loop operation. Test results for one system are obtained. Using a standard control algorithm from the linear control theory, a method of reducing steady-state speed error is demonstrated. No case of instability is found using various starting speeds, final speeds, and controller parameters for test results. Simulation results are obtained for the closed-loop operation using a controller model previously obtained for open-loop operation of this type system. The model contains multiple nonlinearities. No case of instability is found for various starting speeds, final speeds, controller parameters, and motor parameters for the simulation. View full abstract»

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