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System Theory, 1993. Proceedings SSST '93., Twenty-Fifth Southeastern Symposium on

Date 7-9 March 1993

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Displaying Results 1 - 25 of 122
  • Author index

    Publication Year: 1993
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    Freely Available from IEEE
  • 1993 (25th) Southeastern Symposium on System Theory

    Publication Year: 1993
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    Freely Available from IEEE
  • Robust position tracking control for rigid-link flexible-joint robots

    Publication Year: 1993 , Page(s): 358 - 362
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    The robust tracking controller for rigid-link flexible-joint (RLFJ) robots presented by D. M. Dawson et al. (1991) is redesigned. The controller exploits aspects of the dynamic model to provide a global uniform ultimately bounded (GUUB) stability result despite the presence of parametric uncertainty, joint flexibility, and mechanical actuator dynamics. The controller delivers the GUUB result for both the position and the velocity error. The redesign enables the final ball in which the link tracking error resides to be arbitrarily shrunk and the exponential rate at which the error approaches that ball to be increased by adjustment of the control gains View full abstract»

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  • SPICE-A system analysis program?

    Publication Year: 1993 , Page(s): 195 - 199
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    The use of SPICE behavioral models for system analysis is studied. The basic structure of behavioral models is discussed. Examples of the simulation of a system differential equation using an analog computer-type approach and the simulation of a feedback control system are given. The analysis technique is based on a block diagram description of system elements using subcircuits that lead to a very simple SPICE netlist. A library of basic system elements, SYS.LIB, has been developed for the use of SPICE as a system analysis program View full abstract»

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  • Genetic algorithm composes music

    Publication Year: 1993 , Page(s): 223 - 227
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    Genetic algorithms (GAs) and thematic bridging are applied to composition. Thematic bridging allows for the specification of thematic material (frequency, duration, and amplitude) to the GA. The GA controls a dynamic operation set that dictates the placement and arrangement of the thematic material View full abstract»

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  • An analytic study of porosity evolution in powder metallurgy forming process

    Publication Year: 1993 , Page(s): 210 - 214
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    The behavior of a porous metal in a closed-die compression test is studied with the aid of a Gurson-type model, and the results are compared with the results obtained from its quadratic approximation and the yield functions of S. Shima and M. Oyane (1976) and S.M. Doraivelu et al. (1984). Once the initial porosity and the effective stress-strain relation for the matrix is provided, the response of the powder compact can be predicted for a closed-die compaction case. The simulation demonstrates that quadratic approximation gives a response very close to that predicted by the yield functions. The Gurson-type model seems to be inaccurate at high initial porosities. However, more mechanical tests need to be performed on these yield functions before any conclusions can be made View full abstract»

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  • Design of a robotic feeder

    Publication Year: 1993 , Page(s): 363 - 367
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    The use of US Office of Technology Assessment (OTA) recommendations to develop the design specifications of an inexpensive two-degree-of-freedom robot arm for use in rehabilitation applications is described. The current status of the robotic self-feeder is presented along with the mechanical, electrical, and control software design View full abstract»

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  • Pixel-feature-controlling edge detection based on regularization (PEDBOR)

    Publication Year: 1993 , Page(s): 498 - 502
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    The PEDBOR algorithm, in which a threshold function is used for all images, is presented. The algorithm is iterative. In each iteration, pixels are first grouped into three categories: edge pixels, homogeneous region pixels, and noise pixels based on the magnitude of the gradient and the orientation distribution of the gradient in the neighborhood of each pixel. After grouping, a regularization process is applied to the pixels. Unlike other regularization methods, the PEDBOR algorithm chooses regularization parameters, which control the spatial smoothness of processed images and the fidelity of the processed images to original images, according to the pixel type. The algorithm is suitable for a wide range of images and is robust in a variety of noisy situations View full abstract»

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  • Total least squares and constrained least squares applied to frequency domain system identification

    Publication Year: 1993 , Page(s): 285 - 290
    Cited by:  Papers (2)
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    Total-least-squares and constrained-least-squares methods are applied to the Transfer Function Determination Code (TFDC). TFDC is a frequency domain system identification code for determining the SISO input-output transfer function of a system from experimentally derived frequency response data. TFDC is modified to implement a total-least-squares solution, to employ a solution to the combined least-squares/total-least-squares problem, and to apply constrained least squares to ensure quadrantal symmetry of the poles and zeros. Results of applying each method to an example system are presented and compared View full abstract»

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  • A novel approach to synthesis of threshold functions

    Publication Year: 1993 , Page(s): 200 - 204
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    It is noted that threshold elements consist of fewer components and simpler interconnections than the corresponding circuits implemented with conventional gates. The algebra involved in realizing threshold functions is quite different from than the techniques employed for conventional circuits. Existing techniques for synthesis of threshold functions are cumbersome when it comes to practical implementation. A systematic procedure, with examples, for realizing threshold switching functions is presented View full abstract»

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  • An expert system for digital switch alarm processing

    Publication Year: 1993 , Page(s): 229 - 232
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    An expert system for processing the alarm conditions of a digital telephone switching system is proposed. The resulting expert system saves the user time in reacting to alarm conditions. The expert system makes dealing with system alarms a user-friendlier procedure. Normally, a skilled technician is essential to react to and clear alarm situations. The expert system makes alarm clearing a computer guided procedure. The advantages of the system are increased availability and faster response time View full abstract»

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  • Applications of GA-based optimization of neural network connection topology

    Publication Year: 1993 , Page(s): 333 - 337
    Cited by:  Papers (1)
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    A genetic algorithm (GA) is used to explore the connection space of an artificial neural network (ANN) with the objective of finding a sparsely connected network that yields the same accuracy as a fully connected network. Such sparsity is desired as it improves the generalization capabilities of the mapping. The ANN with the GA-chosen set of connections is then trained using a supervised mode of learning known as backpropagation error. Using this technique, three different applications are analyzed View full abstract»

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  • Design of a programmable rainfall simulator

    Publication Year: 1993 , Page(s): 215 - 217
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    A programmable controller (PIC) was designed to provide a greater flexibility in rainfall simulator research. The PIC controlled the rainfall simulator using a process control board employing a microprocessor. This control board provided programmable capability previously unavailable in field research. Software to control the system was developed using assembly language and a microprocessor emulator. This software provided user-friendly interaction and the ability for variations in rainfall intensity and storm duration in simulated rainfall studies View full abstract»

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  • A comparison of methods for the optimization of VGA colormaps

    Publication Year: 1993 , Page(s): 508 - 512
    Cited by:  Papers (1)  |  Patents (1)
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    The results of a project investigating the creation of an optimum colormap for a color image are presented. Optimization methods are investigated to obtain not only the best method, but also alternate methods which provide high quality results in reasonable time. The colormap generation is presented as a two step process which includes an initial colormap selection followed by the optimization of the colormap. Three optimization techniques are investigated: the Linde-Buzo-Gray method, simulated annealing, and a new minimum variance method developed by the authors. Color images with an original 32,768 possible colors are coded using only 256 colors View full abstract»

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  • An efficient park service management package

    Publication Year: 1993 , Page(s): 436 - 440
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    The initial results of an ongoing effort to develop a software package for computerizing the reservation system at the Great Smokey Mountains National Park services are reported. The package is a sophisticated but user-friendly software tool that will ease the problem of keeping track of reservations at the park. It uses advanced routines that are specifically written in assembly language for fast execution. It employs sophisticated database management routines for efficient operation and offers several protection levels to ensure the integrity of the database View full abstract»

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  • Fast progressive reconstruction of images in DCT domain

    Publication Year: 1993 , Page(s): 503 - 507
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    Progressive image transmission (PIT) using the discrete cosine transform (DCT) is considered. An approach to fast progressive reconstruction (FPR) of DCT images is presented. The approach is based on the observation that typical input matrices to IDCT are sparse in PIT. By exploiting the sparsity of a matrix, nonzero elements in the matrix can be processed separately and efficiently. The approach allows any scanning patterns including the zig-zag scan and those incorporating human visual sensitivity. This flexibility distinguishes it from recent approaches to FPR of DCT images View full abstract»

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  • Speaker-independent voiced-stop-consonant recognition using a block-windowed neural network architecture

    Publication Year: 1993 , Page(s): 400 - 404
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    The authors study several of the more well-known connectionist models, and how they address the time and frequency variability of the multispeaker, voiced-stop-consonant recognition task. Among the network architectures reviewed or tested for were the self-organizing feature maps (SOFM) architecture, various derivatives of this architecture, the time-delay neural network (TDNN) architecture, various derivatives of this architecture, and two frequency-and-time-shift-invariant architectures, frequency-shift-invariant TDNN, and the block-windowed neural network (FTDNN and BWNN). Voiced-stop speech was extracted from up to four dialect regions of the TIMIT continuous speech corpus for subsequent preprocessing and training and testing of network instances. Various feature representations were tested for their robustness in representing the voiced-stop consonants View full abstract»

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  • Design of an expert system for transmission planning

    Publication Year: 1993 , Page(s): 105 - 109
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    An expert system for transmission planning (ESTP) that encapsulates the use of conventional power system analysis tools without actual or functional code duplication, which is in the developmental stage, is described. The ESTP allows utility specifics to be added, so that system planning peculiarities can be taken into account View full abstract»

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  • Characterization of an infra-red multi-position sensor system

    Publication Year: 1993 , Page(s): 291 - 295
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    The results of calibrating an infrared multiposition sensor system are presented. The system is characterized from both a spatial position accuracy and frequency domain point of view. Data are presented to support the conclusions drawn from these results View full abstract»

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  • Programmable logic devices in undergraduate digital design courses

    Publication Year: 1993 , Page(s): 416 - 417
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    It is pointed out that design automation tools and programmable logic devices allow the student to put the design into a single chip and test and debug the logical operations with a simulator. Students enjoy applying the programmable logic devices while gaining knowledge of current design practices. An actual senior design project is used as an example View full abstract»

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  • Non-inductive impedance transformer

    Publication Year: 1993 , Page(s): 155 - 158
    Cited by:  Papers (1)
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    An innovative design for a noninductive transformer circuit that transforms values of impedance less than 1 Ω to very high values of approximately several kΩ is based on GaAs CHIGFET technology, with intrinsic radiation hardness in excess of several hundred megarads. A principal advantage of the circuit is that the speed and bandwidth sensitivity is weakly affected by detector source capacity (up to 1 nF), thereby allowing greater design flexibility for both hadronic and electromagnetic calorimetry, or even charge particle detection (tracking) integrated within the same device. The simulated risetime is less than 2 ns, and power dissipated is less than 40 mW View full abstract»

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  • Design and simulation of a modified duobinary acquisition system

    Publication Year: 1993 , Page(s): 576 - 580
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    The implementation of a fast timing recovery system for the modified duobinary pulse amplitude (PAM) system is described, the implementation was verified by simulation, and the hang-up effects were examined. Simulation results for key components of the system and some key system parameters, such as the deviation constant and the loop gains, are in good agreement with previously published results View full abstract»

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  • A heuristic approach to the computation of 3D-ray trajectories in step index optical fibers

    Publication Year: 1993 , Page(s): 179 - 183
    Cited by:  Papers (1)
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    Three-dimensional-ray trajectories in an optical fiber are derived using a simple correspondence principle. The ray trajectories are linked to the mode number of the exact waveguide solutions. The analysis and simulations presented are in terms of dimensionless parameters needed to characterize the optical fiber. Specifically, this includes the V-parameter, the core index of refraction, and the numerical aperture. The curves for allowed radial and azimuthal mode numbers are presented in terms of dimensions that are normalized by the core radius. The approach is extensible to graded-index fibers View full abstract»

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  • Observability requirements for passive target tracking

    Publication Year: 1993 , Page(s): 253 - 257
    Cited by:  Papers (3)
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    Observability requirements for passive target tracking in a three-dimensional coordinate system are derived. The observability problem is formulated as an optimization problem. Certain practical situations, previously known, can be identified from the established observability requirements. However, direct application of these theoretical results does not seem to be trivial for a practical situation View full abstract»

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  • New DSP microprocessor-based programmable interface components

    Publication Year: 1993 , Page(s): 205 - 208
    Cited by:  Papers (1)
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    Two new interface components and their high-potential payoff applications are described. The architectures on which these components are based consist of a DSP microprocessor driving a digital-to-analog converter (DAC), and an analog-to-digital converter (ADC) driving a DSP microprocessor. These interface components could be described as smart DACs or smart ADCs, respectively View full abstract»

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