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System Theory, 1989. Proceedings., Twenty-First Southeastern Symposium on

Date 26-28 March 1989

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Displaying Results 1 - 25 of 134
  • Proceedings. The Twenty-First Southeastern Symposium on System Theory (Cat. No.89CH2714-4)

    Publication Year: 1989
    Request permission for commercial reuse | PDF file iconPDF (131 KB)
    Freely Available from IEEE
  • Digital optical modified signed-digit arithmetic based on symbolic substitution and its encoding scheme

    Publication Year: 1989, Page(s):252 - 256
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (380 KB)

    The authors propose an encoding scheme suitable for a digital optical modified signed-digit arithmetic processor that is based on symbolic substitution. The processor performs binary addition and subtraction in an extremely parallel manner; i.e. the desired result is obtained in three steps, independent of word and array size of the input operands. The encoding scheme is designed to prevent the cr... View full abstract»

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  • A digital simulation model for wind-diesel conversion scheme

    Publication Year: 1989, Page(s):160 - 166
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    The development of a digital computer simulation on a nonlinear model of a unified wind-diesel interface scheme is presented. Wind energy is converted by a self-excited induction generator and interfaced to the diesel-driven synchronous generator by DC link fed by a current-source inverter. The nonlinear model is linearized around an operating point, and the derived linear models are utilized to d... View full abstract»

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  • Stabilization of discrete-time dynamical systems via projection methods

    Publication Year: 1989, Page(s):305 - 309
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (212 KB)

    The problem of stabilizing linear discrete-time dynamical systems is solved using a projection approach. Two state-feedback stabilizing controllers that steer the trajectory of the system onto a desired hyperplane and guarantee asymptotic stability are derived. The first controller reaches the preferred hyperplane asymptotically, whereas the second reaches it in one step, and they both steer the s... View full abstract»

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  • Upper bound frequencies of two dimensional signals

    Publication Year: 1989, Page(s):258 - 263
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    Two-dimensional (2-D) signals are considered, and expressions calculated for the uniform upper bound frequencies for certain classes of functions such that the contribution of frequencies higher than these bounds is less than some specified value given by the error criterion. Two classes of 2-D signals are considered: signals that can be expressed as a convolution of two functions, each of which i... View full abstract»

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  • General adaptive load apportioning for two cooperating robots

    Publication Year: 1989, Page(s):329 - 333
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    The load-sharing-force (LSF) control method for two-arm systems grasping a rigid object is expanded. The LSF control addresses three problems: load sharing; control of interactive forces; and accurate position control. A diagonal matrix α determines how the load is apportioned to each manipulator. An external input specifies the desired compression, tension, or torsion to be applied to the o... View full abstract»

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  • Application of linear multivariable control design for the GE-21 turbofan jet engine

    Publication Year: 1989, Page(s):167 - 171
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    Novel designs are proposed for use in the multivariable control of the GE-21 engine. The designs utilize linear multivariable control theory to generate a new linear quadratic regulator (LQR) followed by loop transfer recovery (LTR) to obtain a robust linear quadratic Gaussian (LQG) controller. The engine control problem and the design process are described. The design techniques involve the analy... View full abstract»

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  • Using the μ-interaction measuring in the design and stability analysis of decentralized control structures

    Publication Year: 1989, Page(s):64 - 70
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    The results of using the μ-interaction measure as an analysis tool in systematically designing decentralized controllers for multivariable systems are given. The μ-interaction measure serves as the upper bound for the maximum allowable gains of a diagonal controller such that stability of the closed-loop diagonal system also implies stability of the closed loop full system. Several examples ... View full abstract»

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  • An optical line of sight sensor for the pinhole facility

    Publication Year: 1989, Page(s):536 - 540
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    A scale model of the optical line-of-sight sensor that measures the pointing angle error to the sun for the Space-Shuttle-based pinhole facility has been designed and tested in the laboratory. This sensor consists of a pinhole camera with two pairs of perpendicularly mounted linear photodiode arrays to detect the intensity distribution of the solar image produced by the pinhole. The video signal o... View full abstract»

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  • The error probability for the BPSK/BPSK and OQPSK/BPSK spread spectrum communication systems in the presence of single tone jammer

    Publication Year: 1989, Page(s):584 - 588
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    The error probability of BPSK/BPSK and OQPSK/BPSK direct-sequence spread-spectrum communication systems, in the presence of the single tone jammer, is developed using a simple technique. This technique clearly illustrates the same error probability for the OQPSK/BPSK and BPSK/BPSK systems. To measure the bit error probability, it is necessary to know the test statistics of the data, jammer, and no... View full abstract»

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  • Random number generator for 16-bit machines

    Publication Year: 1989, Page(s):84 - 88
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (340 KB)

    A general 16-bit multiplicative congruential generator is developed and tested using the chi-square goodness-of-fit test and the Kolmogorov-Smirnov test. The generator is simple and is shown to have good randomness properties for the generation of uniform random numbers. It is also shown that this generator is portable in the sense that it does not overflow the 16-bit computer or require a double-... View full abstract»

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  • A reconfigurable systolic array for polynomial multiplication modulo Xn±1

    Publication Year: 1989, Page(s):460 - 464
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    A simple reconfigurable processor array that utilizes the polynomial residue number system (PRNS) for polynomial multiplication is presented. The mesh-connected systolic array is, in fact, a combination of linear one-dimensional arrays operating in parallel. The reconfiguration scheme is based on a dual role played by the processing elements constituting the array View full abstract»

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  • Optimization of diode-loaded dipole antenna

    Publication Year: 1989, Page(s):367 - 371
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    A circuit model for a microwave diode-loaded dipole electric field measurement probe that is valid for frequencies below 10 GHz is presented. Assumptions are made to allow linear analysis based on the Laplace transform method. Optimized design criteria for the probe are then developed, the major considerations being large bandwidth, independence of temperature, and maximum output. Experimental mea... View full abstract»

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  • Representing structurally adaptive systems with state variables and logic programs

    Publication Year: 1989, Page(s):178 - 182
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    It is suggested that a structurally adaptive system can be best represented using a state-variable model with state or output feedback and a validity vector that indicates the operability of sensors and actuators. Reconfiguration operators can be represented by logic programs. A brief survey of previous work in the nuclear industry on the representation of adaptive systems follows. The state-varia... View full abstract»

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  • Identification and control of large flexible spacecraft

    Publication Year: 1989, Page(s):284 - 288
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    The authors present a system identification technique that represents the structural dynamics of large, flexible space structures in terms of a reduced-order modal model. The finite-element method is used to reduce the order of the physical model, and then the model is transformed from a physical to a modal form. The maximum-likelihood method is used to parameterize the modal model on the basis of... View full abstract»

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  • A technique to stabilize the output voltage level of an emitter follower

    Publication Year: 1989, Page(s):524 - 526
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (140 KB)

    The emitter follower configuration, which is usually driven by another amplifier stage, is discussed. Together, the preceding and emitter follower stages are modified to provide constant-output DC levels. A design method to stabilize these voltage levels is presented. Several practical circuits are illustrated. Typical results show the output DC voltage to have a temperature coefficient of only 0.... View full abstract»

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  • Simulating the nonstationary behavior of communication networks

    Publication Year: 1989, Page(s):589 - 593
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    The problem of simulating communication networks under nonstationary conditions is considered. The critical issues in simulating the nonstationary behavior, such as determining appropriate performance measures, calculating confidence intervals, and selecting initial conditions, are discussed and approaches to their solutions are proposed. To illustrate some of the issues, results for the problem o... View full abstract»

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  • Modular state variable simulation of spacecraft power systems including nonlinear inductances

    Publication Year: 1989, Page(s):127 - 131
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    Some preliminary results of a study directed at the modeling and simulation of spacecraft power systems are presented. Each power device is modeled as a two-port subnetwork. An appropriate set of state-space equations for each two-port model is derived, with port voltages as the independent variables. The first device modeled is the series resonant converter, which includes a nonlinear inductor. S... View full abstract»

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  • Maximal-length pseudorandom number generator

    Publication Year: 1989, Page(s):89 - 92
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    A pseudorandom generator for decimal numbers is considered. This generator is based on combination of a binary and a quinary m-sequence. It is shown that with an appropriate mapping the autocorrelation function of the decimal sequence takes on only the three levels 1, 0.5, and 0. This effectively renders the numbers uncorrelated, except at values equal to the lengths of the individual maximal-leng... View full abstract»

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  • Accommodation of input-derivatives in linear adaptive control

    Publication Year: 1989, Page(s):626 - 628
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    It is shown how the author's theory (1984, 1988) of linear adaptive control can be generalized to accommodate plant models having input-derivative (numerator dynamics) terms. This generalization significantly extends the range of practical applications for linear adaptive control. Only the main ideas and procedures for modifying linear adaptive control theory to accommodate input-derivative terms ... View full abstract»

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  • Model-based control of robots including actuator dynamics

    Publication Year: 1989, Page(s):334 - 337
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    A model-based control method in which the model of the mechanical plant is augmented by the actuator dynamics is proposed. The reflex-action-position control method is expanded to fit the higher order dynamics. The control law has a third-order feed-forward term and feedback compensation for the errors in acceleration, rate, and position. Thus the governing equation in the error space is third ord... View full abstract»

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  • Image enhancement and processing for positron emission tomography

    Publication Year: 1989, Page(s):513 - 517
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    A filtering method for positron emission tomography is proposed. The image is converted from the rectangular x-y coordinate system to the polar ρ-θ coordinate system. This causes the radial noise to map into horizontal lines. Using the Fourier transform, radial noise is then mapped into and around the vertical axis of the Fourier spectrum in the corresponding ω-&t... View full abstract»

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  • A control theory perspective of iterative numerical methods

    Publication Year: 1989, Page(s):71 - 73
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    Interactive numerical methods are examined from the perspective of the theory of feedback control systems. Results show that a linear iterative numerical scheme is readily described by a system of linear discrete state equations. It follows that the process is also describable using Z-transform techniques if desired, and that standard control system analytical procedures for stability analysis can... View full abstract»

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  • Si diode under avalanche breakdown as a light emitting source for VLSI optical interconnect

    Publication Year: 1989, Page(s):677 - 680
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    Light-emission properties of a reverse-biased silicon diode under avalanche breakdown are investigated for optical interconnections for VLSI systems. Silicon, being an indirect bandgap semiconductor, is a poor material for light emission from forward biased diodes. The optical emission at reverse breakdown is weak but is coupled to an optical fiber and detected by a photodiode, indicating its pote... View full abstract»

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  • Numerical simulations of current collection for the electrodynamic tether in space

    Publication Year: 1989, Page(s):376 - 379
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    Numerical simulations have been carried out to determine the I -V characteristic of a long cylindrical body moving in a magnetized plasma. Results show that at relatively small body voltages, the collected current in the presence of magnetic field is insignificantly small compared with the situation without a magnetic field. However, when the body voltage increases, the current c... View full abstract»

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