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Systems, Man and Cybernetics, IEEE Transactions on

Issue 4 • Date Jul/Aug 1991

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Displaying Results 1 - 23 of 23
  • Fuzzy set representation of neural network classification boundaries

    Publication Year: 1991 , Page(s): 735 - 742
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (724 KB)  

    In neural network classification techniques, the uncertainty of a new observation belonging to a particular class is difficult to express in statistical terms. On the other hand, statistical classification techniques are also poor for supplying uncertainty information for new observations. The use of fuzzy sets is a promising approach to providing imprecise class membership information. The monotonic function neural network is a tool that can be used to develop fuzzy membership functions. This research suggests that a multiarchitecture monotonic function neural network can be used for fuzzy set representation of classification boundaries in monotonic pattern recognition View full abstract»

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  • A two-phase interactive solution method for multiple-objective programming problems

    Publication Year: 1991 , Page(s): 743 - 749
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    There has been increasing emphasis on interactive methods for the solution of multiple objective programming (MOP) models. These solution methods are commonly founded on economic definitions of rationality and assume the existence of a well-defined, stable utility function. A two-phase solution method that is behaviorally founded and draws on the literature about the structure of MOP models is considered. Some relevant behavioral issues are discussed, and a solution approach that integrates the more structural MOP research with a proven behavioral model of human decision-making is presented. The method seeks to accommodate the behavioral characteristics of human decision-making situations. An example of the solution method for the group decision-making situation is given View full abstract»

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  • Groupware research and technology issues with application to software process management

    Publication Year: 1991 , Page(s): 704 - 712
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1020 KB)  

    Technology for actively supporting groups of collaborating users is being applied to many kinds of cooperative work activities. The following topics are addressed: (1) the authors' definition of groupware, (2) a conceptual framework in which to examine research issues, and (3) high-level groupware research issues within this framework. One potentially fertile area of application for such technologies is the problem of software process management. Software process means one of the teamwork, cooperation, coordination, and communication activities that occur within and across groups and organizations of persons throughout the life of software projects, including processes that occur under the broad categories of proposal writing, software engineering, development, and maintenance. This application domain contains a number of research issues and technology problems in such areas as communication, distribution, concurrence control, and human-computer interface design. The research areas needed for groupware to facilitate software processes are described View full abstract»

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  • A knowledge-based pattern recognition approach for real-time diagnosis and control of fermentation processes as variable structure plants

    Publication Year: 1991 , Page(s): 908 - 914
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (720 KB)  

    A fundamental property of microbial systems, which are the central part of fermentation plants, is their structural variability. From the viewpoint of process control, this imposes serious difficulties because the problem of controlling variable structure plants is analytically unsolved. However, the amalgamation of some nonstandard methodologies offers possibilities for handling the variable structure phenomenon. Of special interest is the knowledge-based pattern recognition approach, which provides a natural basis for classification of the structural state of the microbial systems, and is well-suited to their uncertain characteristics. The development of such knowledge-based techniques and their application to the control of an amino acid production process are discussed View full abstract»

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  • Optimization of functions with many minima

    Publication Year: 1991 , Page(s): 840 - 849
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1080 KB)  

    A numerical method for finding the global minimum of nonconvex functions is presented. The method is based on the principles of simulated annealing, but handles continuously valued variables in a natural way. The method is completely general, and optimizes functions of up to 30 variables. Several examples are presented. A general-purpose program, INTEROPT, is described, which finds the minimum of arbitrary functions, with user-friendly, quasi-natural-language input View full abstract»

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  • A model of distributed team information processing under ambiguity

    Publication Year: 1991 , Page(s): 713 - 725
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1132 KB)  

    Distributed information processing by a three-person hierarchical team, consisting of a primary decision maker (DM) and two expert subordinates, is considered. The problem context is binary hypotheses testing, wherein the team is asked to decide whether a contact is a threat or a neutral based on distributed, noisy, and at times ambiguous, measurements. A normative Bayesian model, which prescribes the behavior of an optimal team, is developed. The normative predictions are compared with the experimental data, and the cognitive biases of conservatism and of undervaluing of subordinates' reports by the primary DM are identified. A normative-descriptive model incorporating these human biases is developed using Kalman filtering (least squares) theory. The output of the resulting normative-descriptive model is shown to provide an excellent match with the experimental data View full abstract»

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  • Visualization of structural information: automatic drawing of compound digraphs

    Publication Year: 1991 , Page(s): 876 - 892
    Cited by:  Papers (28)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1160 KB)  

    An automatic method for drawing compound digraphs that contain both inclusion edges and adjacency edges are presented. In the method vertices are drawn as rectangles (areas for texts, images, etc.), inclusion edges by the geometric inclusion among the rectangles, and adjacency edges by arrows connecting them. Readability elements such as drawing conventions and rules are identified, and a heuristic algorithm to generate readable diagrams is developed. Several applications are shown to demonstrate the effectiveness of the algorithm. The utilization of curves to improve the quality of diagrams is investigated. A possible set of command primitives for progressively organizing structures within this graph formalism is discussed. The computational time for the applications shows that the algorithm achieves satisfactory performance View full abstract»

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  • Z-Basic algorithm for collision avoidance system

    Publication Year: 1991 , Page(s): 915 - 921
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    A Z-Basic prediction algorithm for an aircraft ground-based collision avoidance system is presented. This system searches for mutually overlapping prediction intervals that are influenced by the aircraft's maneuver capabilities and surveillance accuracy. Z-Basic provides a powerful, fast, interactive, simple to use, and inexpensive Basic compiler. The algorithm is applied to a typical terminal airspace situation. The computer program was executed on Macintosh+, and the execution was less than one minute. The program is easy to understand and implement View full abstract»

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  • Failure propagation trees for diagnosis in manufacturing systems

    Publication Year: 1991 , Page(s): 767 - 776
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1044 KB)  

    The diagnostic step of the error recovery process in manufacturing systems is discussed, and an algorithm for constructing and pruning a failure propagation tree is formalized. The methodology of building of failure propagation tree is proposed. This methodology is based on a hierarchical process plan, a precondition-postcondition model of manufacturing operations, and a classification of the failure reasons. The hierarchical operation model embodies the process plan, and the functional and structural classifications for each failure reason of every operation in the model. Based on the hierarchical operation model, the final failure propagation tree is generated or expanded by linking the operations in the model. The expansion process is accomplished by iteratively applying the expansion rule and priority rule to the operations in the hierarchical operation model View full abstract»

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  • Closed-form dynamic model of planar multilink lightweight robots

    Publication Year: 1991 , Page(s): 826 - 839
    Cited by:  Papers (69)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (852 KB)  

    Closed-form equations of motion are presented for planar lightweight robot arms with multiple flexible links. The kinematic model is based on standard frame transformation matrices describing both rigid rotation and flexible displacement, under small deflection assumption. The Lagrangian approach is used to derive the dynamic model of the structure. Links are modeled as Euler-Bernoulli beams with proper clamped-mass boundary conditions. The assumed modes method is adopted in order to obtain a finite-dimensional model. Explicit equations of motion are detailed for two-link case assuming two modes of vibration for each link. The associated eigenvalue problem is discussed in relation with the problem of time-varying mass boundary conditions for the first link. The model is cast in a compact form that is linear with respect to a suitable set of constant parameters. Extensive simulation results that validate the theoretical derivation are included View full abstract»

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  • A fully autonomous active sensor-based exploration concept for shape-sensing robots

    Publication Year: 1991 , Page(s): 850 - 860
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (980 KB)  

    A technique is developed for the automatic, online generation of trajectories for robotic exploration of unknown objects. For manipulators and end effectors with an arbitrary assortment of sensing apparatus, especially tactile, the Kalman filtering approach is given for the estimation of unknown surface parameters. A cost function is found based on the inverse error covariance matrix for the parameter estimates. It is shown that this cost function can be written in terms of tangent vectors on the surface of the object. The cost can therefore be minimized over possible end effector velocities, resulting in optimally efficient exploration of the surface. Given an estimator and system model, the exploration path automatically generated in this way endows the robot with the ability to seek out geometric surface features that provide the most utility for the improved convergence of the parameter estimate. Computer simulations for a nine-dimensional surface parameter vector show that the algorithm is fast, accurate, and completely independent of the parametrization chosen for the analytic surface models View full abstract»

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  • Dynamic cooperative electricity exchange in a power pool

    Publication Year: 1991 , Page(s): 758 - 766
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (752 KB)  

    An approach to the design of a transaction agreement in an electric power pool is proposed. The electricity exchange takes place over a fixed time interval in a stochastic environment. The incentive for the electricity exchanges is due to disparity in the time patterns of the marginal operating costs between the utilities. Electricity produced at the different periods is used as the medium of exchange and no monetary payments between the utilities take place. The exchange policy is chosen so that the savings are distributed to the participants in an equitable manner. The contract definition problem is approached from the point of view of cooperative game theory. Because of the uncertainty, the contract is adjusted at each period so that fair division of the cost savings is obtained View full abstract»

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  • Axiomatization of qualitative belief structure

    Publication Year: 1991 , Page(s): 726 - 734
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (764 KB)  

    There are important theoretical and practical reasons to study belief structures. Similar to qualitative probability, qualitative belief can be described in terms of a preference relation. The precise conditions that a preference relation must satisfy such that it can be faithfully represented by a belief function are specified. Two special classes of preference relations identified are weak and strict belief relations. It is shown that only strict belief relations are consistent (compatible) with belief functions. The axiomization of qualitative belief provides a foundation to develop a utility theory for decision making based on belief functions. The established relationship between qualitative probability and qualitative belief may also lead to a better understanding and useful applications of belief structures in approximate reasoning View full abstract»

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  • Design and implementation of a fuzzy controller for a high performance induction motor drive

    Publication Year: 1991 , Page(s): 921 - 929
    Cited by:  Papers (34)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB)  

    A limit-cycle controlled induction motor drive with a fuzzy controller has been designed and implemented. The torque and flux of the proposed drive system are regulated by the limit-cycle control technique. It follows that very quick torque response can be achieved. Since the dynamic model of this type of drive system is not easy to obtain, a fuzzy controller was developed and used in the speed control feedback loop to obtain good dynamic rotor speed response. The fuzzy algorithms in the proposed controller are systematically found from intuition and experience about the drive systems. The experimental results indicate that good dynamic speed performance can be achieved by the proposed controller. Moreover, since the rotor parameters are not needed in the implementation of the drive system, and due to the inherent feature of high adaptive capability possessed by the fuzzy controller, the performance of the controller drive system is rather insensitive to the parameter and operating condition changes View full abstract»

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  • Time scaling of cooperative multirobot trajectories

    Publication Year: 1991 , Page(s): 900 - 908
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (752 KB)  

    An algorithm to modify the trajectories of multiple robots in cooperative manipulation is developed. If a given trajectory results in joint torques that exceed the admissible torque range for one or more joints, the algorithm slows down or speeds up the trajectory so as to maintain all the torques within the admissible boundary. The proposed trajectory-modification algorithm uses the concept of time scaling developed by Hollerbach (1984) for single robots. The trajectory scaling scheme described in this paper requires the use of linear programming techniques and is designed to accommodate the internal force constraints and payload distribution strategies. The actuator torques may be found from the quadratic minimization that has the effect of lowering energy consumption for the trajectory. A scheme for generating a robust multirobot trajectories when the carried load mass and inertia matrix are unknown but vary within a certain range is described View full abstract»

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  • Neural networks in process fault diagnosis

    Publication Year: 1991 , Page(s): 815 - 825
    Cited by:  Papers (54)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    Fault detection and diagnosis is an important problem in process automation. Both model-based methods and expert systems have been suggested to solve the problem, along with the pattern recognition approach. A number of possible neural network architectures for fault diagnosis are studied. The multilayer perceptron network with a hyperbolic tangent as the nonlinear element seems best suited for the task. As a test case, a realistic heat exchanger-continuous stirred tank reactor system is studied. The system has 14 noisy measurements and 10 faults. The proposed neural network was able to learn the faults in under 3000 training cycles and then to detect and classify the faults correctly. Principal component analysis is used to illustrate the fault diagnosis problem in question View full abstract»

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  • An experimental study comparing the effectiveness of computer graphics data versus computer tabular data

    Publication Year: 1991 , Page(s): 897 - 900
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    A number of studies that compare the effectiveness of data presented in graphic form versus data presented in tabular form have been performed. Results have been mixed. In a study by Dickson et al. (1986) that used business students as subjects it is suggested that task variables are paramount in the determination of such effectiveness. It is suggested that the type of data and type of subject used in the work by Dickson et al. favored tabular presentation and compromise any generalization of their conclusions. The current study finds that user training/expertise is a critical variable in determining the effectiveness of graphs versus tables. The conclusion drawn is that a user-friendly system should make both modes available so that the users have the option of selecting their preferred mode View full abstract»

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  • Combination and selection of binary forecasts

    Publication Year: 1991 , Page(s): 750 - 757
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    Binary yes-no forecasts are used to indicate whether a particular set of events will or will not occur. A mechanism for combining independent binary forecasts for the case where likelihood functions are available is given. The decision maker (DM) has to assume a priori from the natural conjugate family of distributions, and uses the forecasts as data points. The assumptions of this model are examined, and some statistical properties are developed. These properties are used to provide a dynamic programming procedure for a priori and sequential selection of an optimal subset of the forecast set when they are costly View full abstract»

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  • On certain classes of spatiotemporal random fields with applications to space-time data processing

    Publication Year: 1991 , Page(s): 861 - 875
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1244 KB)  

    A theory of spatiotemporal random fields is developed as an extension of the Ito-Gel'fand theory of random distributions. Notable characteristics of the most important classes of spatiotemporal fields are examined. The theory is used to describe the correlation structure of generally space nonhomogeneous/time nonstationary processes and to derive optimal estimators for data dispersed simultaneously in space and time. A variety of applications of subtemporal data processing are reviewed. The outcomes of this processing may be not an end in themselves. In several situations they will be the valuable inputs to decision-making processes, risk evaluation methods, control and investment policies, etc View full abstract»

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  • Experimental studies in real-time, Monte Carlo simulation

    Publication Year: 1991 , Page(s): 802 - 814
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1260 KB)  

    Several research concerns resulting from experiments in real-time Monte Carlo simulation are presented. An overview of the computational processes used in the experimental study, a definition for the system state and state transition mechanism, and the performance measures considered are given. The statistical concerns that arise in the analysis of transient phenomena are discussed. The method of statistical analysis incorporated is reported. Research concerns associated with the process are discussed. Future research concerns are related, and current research efforts are summarized. In particular, the development of graphical interfaces to assist the decision maker in the analysis of the real-time data are discussed View full abstract»

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  • Sampling behavior in a four-instrument monitoring task

    Publication Year: 1991 , Page(s): 893 - 897
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    Previous research on human monitoring behavior showed a positive correlation between sampling frequency and signal bandwidth. In those experiments, however, bandwidth was found confounded with a number of critical events. In the present study bandwidth and number of events were not correlated. It demonstrates that bandwidth offers sufficient information to distinguish between signals and that sampling behavior is affected by actual positions View full abstract»

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  • On discovering potential inconsistencies in validating uncertain knowledge bases by reflecting on the input

    Publication Year: 1991 , Page(s): 790 - 801
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    The problem of finding potential inconsistencies during the process of validating knowledge based systems is discussed. A novel methodology, called reflecting on the inputs, is introduced. This effectively requires the knowledge base to stipulate the possible values for the inputs to the system. It is shown that the existence of potential inconsistencies manifest themselves by putting restrictions on the allowable input values View full abstract»

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  • A Petri-net coordination model for an intelligent mobile robot

    Publication Year: 1991 , Page(s): 777 - 789
    Cited by:  Papers (25)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1160 KB)  

    A Petri net model of the coordination level of an intelligent mobile robot system (IMRS) is presented. The purpose of this model is to specify the integration of the individual efforts on path planning, supervisory motion control, and vision system that are necessary for the autonomous operation of a mobile robot in a structured dynamic environment. This is achieved by analytically modeling the various units of the system as Petri net transducers and explicitly representing the task precedence and information dependence among them. The model can be used to simulate the task processing and evaluate the efficiency of operations and the responsibility of decisions in the coordination level of the intelligent mobile robot system. Some simulation results of the task processing and learning are presented View full abstract»

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