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Systems, Man and Cybernetics, IEEE Transactions on

Issue 4 • Date Jul/Aug 1990

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Displaying Results 1 - 20 of 20
  • Eye-gaze word processing

    Publication Year: 1990 , Page(s): 944 - 950
    Cited by:  Papers (12)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (812 KB)  

    Erica is a personal computer operated by eye-gaze. By looking at menu options displayed at different locations on the computer monitor, a disabled user can invoke commands without the need for standard input devices. The design of test entry software for Erica's gaze word processor is described. A basic encoding is accomplished through a static tree-structured menu system, which associates the 85 most common ASCII characters with unique sequences of menus and eye-gaze picks. The expected length of the pick sequences is minimized based on the approximate frequencies of individual characters determined from a 55882 character corpus of English language text. Text entry speeds are further enhanced by adding context-sensitive nodes to the static tree. The menu screens corresponding to these nodes contain the five characters most likely to follow the last two characters entered, based on character transition probabilities derived from the sample corpus View full abstract»

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  • Analyzing manipulator and feel system effects in aircraft flight control

    Publication Year: 1990 , Page(s): 923 - 931
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    The response characteristics of modern, highly augmented aircraft have reached the point where the vehicle and control system dynamics have begun to interact adversely with the actuation dynamics of the human pilot. Actuation dynamics include the characteristics of both the pilot's neuromuscular system and those of the manipulator and feel system by which the pilot's will is imparted to the aircraft. To address this problem, a simple pilot/vehicle model is developed that can be used both to interpret pertinent flight-test and simulation results and to serve as a tractable tool for assessing proposed changes in manipulator-feel system characteristics. The model hypothesizes proprioceptive information to be a fundamental feedback quantity in the pilot's ability to adopt the compensation characteristics required by the crossover model of the human pilot. The model includes manipulator-feel system dynamics, vestibular (motion) feedback, and a rudimentary form of biodynamic feedback. Simple frequency domain control system analysis techniques are applied to the study of manipulator and force feel system effects and to an analysis of the roll ratchet phenomenon View full abstract»

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  • Reliability analysis in intelligent machines

    Publication Year: 1990 , Page(s): 950 - 956
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    Given an explicit task to be executed, an intelligent machine must be able to find the probability of success, or reliability, of alternative control and sensing strategies. By using concepts for information theory and reliability theory, new techniques for finding the reliability corresponding to alternative subsets of control and sensing strategies are proposed such that a desired set of specifications can be satisfied. The analysis is straightforward, provided that a set of Gaussian random state variables is available. An example problem illustrates the technique, and general reliability results are presented for visual servoing with a computed torque-control algorithm. Moreover, the example illustrates the principle of increasing precision with decreasing intelligence at the execution level of an intelligent machine View full abstract»

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  • Discretized pursuit learning automata

    Publication Year: 1990 , Page(s): 931 - 938
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (816 KB)  

    The problem of a stochastic learning automaton interacting with an unknown random environment is considered. The fundamental problem is that of learning, through interaction, the best action allowed by the environment (i.e. the action that is rewarded optimally). By using running estimates of reward probabilities to learn the optimal action, an extremely efficient pursuit algorithm (PA), which is presently among the fastest algorithms known, was reported in earlier works. The improvements gained by rendering the PA discrete are investigated. This is done by restricting the probability of selecting an action to a finite and, hence, discrete subset of [0, 1]. This improved scheme is proven to be ε-optimal in all stationary environments. Furthermore, the experimental results seem to indicate that the algorithm presented is faster than the fastest nonestimator learning automata reported to date, and also faster than the continuous pursuit automaton View full abstract»

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  • Integrated decision support system for environmental planning

    Publication Year: 1990 , Page(s): 777 - 790
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1004 KB)  

    An integrated decision support system for use in environmental planning has been developed. It consists of eight subsystems: three subsystems are used for the management of relevant data and models; two subsystems are used for the identification of environmental problems; and three subsystems are used for modeling and simulation. The purpose of developing this system is to assist in the identification of environmental problems as well as in the building of statistical models that use experts' knowledge and judgment from relevant fields. As an application, the processes involved in analyzing environmental problems and the formulation of fuzzy model to estimate the likely environmental impacts of possible development programs in Tokyo Bay are presented. The system is useful as a decision support tool because it can clarify current and future issues concerning the environment and assist in planning of effective management programs. It also promotes communication between researchers in different scientific fields who are studying complicated environmental problems View full abstract»

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  • Information modeling for computerized manufacturing

    Publication Year: 1990 , Page(s): 758 - 776
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1740 KB)  

    An information modeling and design approach using a metadatabase framework and a two-stage entity-relationship (TSER) methodology to address the system integration problem is presented. The metadatabase framework is a simplification design entailing a federated system architecture, an integrated information model, and a knowledge-based control methodology. The TSER methodology, used for the information model, features both a semantic modeling construct encompassing the US Air Force's IDEF approach and an operational modeling construct for consolidating data structures across the manufacturing facility. Preliminary results of a pilot study, including both modeling and software system development, are included to illustrate the theoretical work View full abstract»

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  • The optimally stable ranges of 2n-legged wave gaits

    Publication Year: 1990 , Page(s): 888 - 902
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1148 KB)  

    The study of the optimally stable range of the wave gait is extended to the 2n-legged case (n⩾2). To accomplish this, an analytical method is applied to compare the longitudinal stability margin of the wave gait with all periodic and regular gaits. It is shown that the wave gait is optimally stable in the range of 3/4⩽β<1 for n=2, which confirms the analytical result of the R.B. McGhee and A.A. Frank (1968); and in the range of 1/2⩽β<1 for n=3, which confirms the numerical results of P. Bessonov and N.V. Umnov (1973). β is the time fraction of a cycle in which a leg is on the ground. For n>4, the wave gait is optimally stable in the range of 1/2⩽β<1 for most of these cases. However, there are 49 cases for which the lower bound of the optimally stable range is higher than 1/2. The optimally stable ranges of these cases are listed. Overall, the wave gait is optimally stable in the range of 2/3⩽β<1 for n⩾4. If the wave gait is compared with periodic and regular gaits, which are either symmetric or constant-phase-incremented, the wave gait is optimally stable in the range of 3/4⩽β<1 for n=2 and in the range of 1/2⩽β<1 for n⩾3 View full abstract»

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  • Application of heuristic search and information theory to sequential fault diagnosis

    Publication Year: 1990 , Page(s): 872 - 887
    Cited by:  Papers (67)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1308 KB)  

    The problem of constructing optimal and near-optimal test sequences to diagnose permanent faults in electronic and electromechanical systems is considered. The test sequencing problem is formulated as an optimal binary AND/OR decision tree construction problem, whose solution is known to be NP-complete. The approach used is based on integrated concepts from information theory and heuristic AND/OR graph search methods to subdue the computational explosion of the optimal test-sequencing problem. Lower bounds on the optimal cost-to-go from the information-theoretic concepts of Huffman coding and entropy are derived. These lower bounds ensure that an optimal solution is found using the heuristic AND/OR graph search algorithms; they have made it possible to obtain optimal test sequences to problems that are intractable with traditional dynamic programming techniques. In addition, a class of test-sequencing algorithms that provide a tradeoff between solution quality and complexity have been derived using the ε-optimal and limited search strategies View full abstract»

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  • Position independent pattern matching by neural network

    Publication Year: 1990 , Page(s): 816 - 825
    Cited by:  Papers (1)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (852 KB)  

    A novel pattern-matching neural network is proposed. The network matches an input to multiple candidates of the stored templates in parallel. It can find the best matching template, whose features are arranged in the same order as those of the input, regardless of positional differences between corresponding features. The network consists of a pattern-matching layer, a minimal distance detection layer, and a recognition layer. The matching between an input pattern and candidates of the to-be-matched template is performed in the pattern-matching layer. The candidates are selected in the minimal distance detection layer, and are fed back in parallel to the pattern-matching layer. The candidate that has features in the same positional order as the input can be determined in the pattern-matching layer. The matched template is classified by the recognition layer. Results of simulation studies on one- and two-dimensional patterns have shown that the network can perform position-independent pattern matching completely View full abstract»

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  • A generalized knowledge-based system for the recognition of unconstrained handwritten numerals

    Publication Year: 1990 , Page(s): 835 - 848
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1008 KB)  

    A method of recognizing unconstrained handwritten numerals using a knowledge base is proposed. Features are collected from a training set and stored in a knowledge base that is used in the recognition stage. Recognition is accomplished by either an inference process or a structural method. The scheme is general, flexible, and applicable to different methods of feature extraction and recognition. By changing the acceptance parameters, a continuous range of performance can be achieved. Encouraging results on nearly 17000 totally unconstrained handwritten numerals are presented. The performance of the system under different recognition-rejection tradeoff ratios is analyzed in detail View full abstract»

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  • Neighboring direction runlength coding: an efficient contour coding scheme

    Publication Year: 1990 , Page(s): 916 - 921
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    An improved exact coding scheme for a two-tone digital contour is proposed. It is assumed that the contour is one pel thick and perfectly 8-connected. The basic idea of the scheme is to segment the contour at the position where 90 degree bends occur. Each segment is considered as a unit for coding. For coding convenience, the subsegments belonging to the segment, and runs in each subsegment, are identified. The codeword consists of subwords representing the starting direction of the segment, subsegment identification, number of runs in the subsegments, and number of pels in the runs. The scheme has been tested on several contours, and experimental results are presented and compared with those of the best known scheme. It is seen that the proposed scheme is consistently better than the NDSC (neighboring direction segment coding) scheme View full abstract»

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  • Task-level tour plan generation for mobile robots

    Publication Year: 1990 , Page(s): 938 - 943
    Cited by:  Papers (5)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    A tour plan generator (TPG) specifically adapted for mobile robots is described. The TPG computes the itinerary of a tour passing through a number of locations. One typical constraint is that a single-armed mobile robot is usually unable to carry more than one object at a time in its gripper. This constraint requires the TPG to generate a tour in which each pick-up location is visited immediately prior to the corresponding drop-off location. A model that makes it possible to reduce this problem to a special case of the traveling salesman problem with asymmetric cost matrix and nonEuclidean distances is introduced. Another constraint in many mobile robots is the need to periodically visit a home location. The TPG introduced here automatically creates multiple subtours such that a predefined maximal length for each subtour is not exceeded. The algorithm obtains near-optimal solutions with short computation times by combining different heuristic tour-construction rules into a heuristic team approach View full abstract»

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  • A probabilistic model of neural networks with static attractors

    Publication Year: 1990 , Page(s): 921 - 922
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    A probabilistic version of the binary Hopfield networks is proposed. Operation of the network is completely parallel, in the sense that evolution of each unit is governed only by its inherent probabilistic law. It is shown that the global state is attracted by one of the equilibria with probability one View full abstract»

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  • Stochastic effectiveness models for human-machine systems

    Publication Year: 1990 , Page(s): 826 - 834
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    Stochastic models for system effectiveness are developed for a multiple-component human-machine system. System effectiveness is defined as the combined measure of availability and reliability at each task-arrival time, when transient human operator behavior is considered in conjunction with the machine state. Because factors such as fatigue, stress, and learning affect the human operator over time, all probability measures for successful human performance are considered to be time-dependent. Performance evaluation models for a generic military system are developed. The modeling techniques can also be used for large-scale, man-machine systems that consist of modern computers and processors View full abstract»

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  • MGA: a decision support system for complex, incompletely defined problems

    Publication Year: 1990 , Page(s): 745 - 757
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1356 KB)  

    Modeling-to-generate alternatives (MGA) is a technique for using mathematical programming models to generate a small number of different solutions for the decision maker to consider when dealing with complex, incompletely defined problems. The logic of MGA is presented in the context of concerns about the limitations of mathematical models and the human decision-makers who use them. Arguments and experimental evidence are presented to support the assumption that the human-machine decision-making system will perform better when the human is presented with a few different alternatives than when presented with a homogeneous set of alternatives, as might result from sensitivity analysis View full abstract»

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  • A comparative study of nonlinear shape models for digital image processing and pattern recognition

    Publication Year: 1990 , Page(s): 858 - 871
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (872 KB)  

    Four nonlinear shape models are presented: polynomial, Coons, perspective, and projective modes. Algorithms and some properties of these models are provided. For a given physical model, such as a perspective model, comparisons are made with other mathematical models. It is proved that, under certain conditions, the perspective models can be replaced by the Coons models. Problems related to substitution and approximation of practical models that facilitate digital image processing are raised and discussed. Experimental results on digital images are presented View full abstract»

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  • Nonlinear operators for improving texture segmentation based on features extracted by spatial filtering

    Publication Year: 1990 , Page(s): 804 - 815
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1104 KB)  

    An unsupervised texture segmentation system using texture features obtained from a combination of spatial filters and nonlinear operators is described. Local texture features are evaluated in parallel by a succession of four basic operations: (1) a convolution for local structure detection (local linear transform); (2) a first nonlinearity of the form f(x)=|x|α; (3) an iterative smoothing operator; and (4) a second nonlinearity g(x). The Karhunen-Loeve transform is used to reduce the dimensionality of the resulting feature vector, and segmentation is achieved by thresholding or clustering in feature space. The combination of nonlinearities f(x)=|x|α (in particular, α=2) and g(x)=log x maximizes texture discrimination, and results in a description with variances approximately constant for all feature components and texture regions. This latter property improves the performance of both feature reduction and clustering algorithms significantly View full abstract»

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  • A unified approach for robot motion planning with moving polyhedral obstacles

    Publication Year: 1990 , Page(s): 903 - 915
    Cited by:  Papers (32)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    A unified approach suitable for path planning with moving polyhedral obstacles is presented. The planner views the space-time configuration of free space as disjoint polytopes that represent a time-dependent environment consisting of moving and stationary objects. Each point in the space-time domain is mapped into a unique polytope set. The planner then constructs a family of feasible collision-free trajectories by searching connected polytopes between the start polytope and the goal polytope that satisfy the speed and time constraints. Finally, a near-optimal trajectory is determined by constrained optimization. This approach does not require that obstacles be nonoverlapping or noncolliding. In addition, the obstacle is allowed to move faster than the planned robot. However, the speed of the obstacle must be piecewise-constant. The proposed approach can be easily extended to motion planning in higher dimensional spaces View full abstract»

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  • Coordinating multilimbed robots for generating large Cartesian force

    Publication Year: 1990 , Page(s): 849 - 857
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (752 KB)  

    Two coordination methods to enable a multilimbed robot to generate large Cartesian forces are presented. The first method selects an optimal configuration for the arm in terms of the force generation, regardless of the position where the force needs to be applied. The position and orientation of the main body are then adjusted to make the end-effector reach the required position. The second method treats the multilimbed robot as a single robotic system and applies the nonlinear programming technique to the system. As a result, optimal configurations are obtained for both the arm and mainbody at the same time View full abstract»

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  • Design of knowledge-rich hierarchical controllers for large functional systems

    Publication Year: 1990 , Page(s): 791 - 803
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1220 KB)  

    A hierarchical structure that utilizes all the functionalities of a large-scale system and unifies the dynamics of the system with its functional behavior is introduced. The proposed hierarchy is formed by decomposing the physical structure of a system and by associating knowledge-rich controllers with the structure. The inclusion of structural information in the hierarchy has several advantages. First, it presents multifunctional descriptions of portions of the system. Then, it provides a modular decomposition such that complete reconstruction of the hierarchy is not required if some parts of the system change. Most importantly, it enables local failure handling and replanning. To demonstrate the physical decomposition, task assignment, and control process, a system with two robot arms and a camera was considered as an example View full abstract»

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