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Systems, Man and Cybernetics, IEEE Transactions on

Issue 5 • Date Sept.-Oct. 1988

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Displaying Results 1 - 16 of 16
  • Minimum cross-entropy spectral analysis of time-varying biological signals

    Publication Year: 1988 , Page(s): 802 - 807
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB)  

    The application of minimum cross-entropy (MCE) spectral analysis to successive blocks of biological time series is considered. Examples demonstrate the effectiveness of the MCE procedure for the analysis of cardiovascular ultrasound return and low-frequency electroencephalograph (EEG) signals.<> View full abstract»

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  • Modelling and control of sewer flow for reduced cost operation of a sewage pumping station

    Publication Year: 1988 , Page(s): 807 - 813
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (636 KB)  

    The development of a control strategy for the scheduling of variable speed pumps at a sewage pumping station is described. In a digital simulation of the system, the total pumping cost was minimized while satisfying the operational hydraulic constraints. The storage capacity in the upstream trunk sewer was utilized to achieve smoother operation of pumps at lower costs. A simple discrete-time model with delay was derived to relate the outflow from an upstream pumping station and the inflow to downstream pumping station. Another model was derived to link the flow depths to pumping rates at a proposed downstream pumping station. These models allowed the prediction of flow to the pumping station and given an estimate of the depth in the sewer at the pumping station; this depth prediction was used to determine whether the system constraints on the flow velocity and Froude number would be met View full abstract»

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  • Learning control of finite Markov chains with an explicit trade-off between estimation and control

    Publication Year: 1988 , Page(s): 677 - 684
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    An efficient scheme is presented for a learning control problem of finite Markov chains with unknown dynamics, i.e. with unknown transition probabilities. The scheme is designed to optimize the asymptotic system performance and for easy application to models with relatively many states and decisions. In this scheme a control policy is determined each time through maximization of a simple performance criterion that explicitly incorporates a tradeoff between estimation of the unknown probabilities and control of the system. The policy determination can be easily performed even in the case of large-size models, since the maximizing operation can be greatly simplified by use of the policy-iteration method. It is proven that this scheme becomes ε-optimal as well as optimal by suitable choice of control parameter values in the sense that a relative frequency coefficient of making optimal decisions tends to the maximum View full abstract»

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  • Optimal noise rejection in linear associative memories

    Publication Year: 1988 , Page(s): 814 - 815
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    An associative memory, designed to recall a data vector when presented with the appropriate uncorrupted key vector and to optimally extract the data vector when presented with a corrupted key vector, is described. The extraction is optimal in the sense that a quadratic cost functional is minimized View full abstract»

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  • An expert system approach to control system design and analysis

    Publication Year: 1988 , Page(s): 685 - 694
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (764 KB)  

    The architecture of CONEX-expert system for control system design and analysis-is presented. The important features of CONEX are discussed and they include: a structured organization of the short-term database, a clustering criteria for partitioning the rule-base into connected rule-spaces, a language for representing the domain-specific rules, and an inference engine that can adopt different search strategies for different rule-spaces. Additionally, an explanation generation module gives CONEX the attribute of user friendliness View full abstract»

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  • Standard scaling in decision graphs: an empirical investigation

    Publication Year: 1988 , Page(s): 824 - 831
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (884 KB)  

    With the proliferation of workstation-based end-user technology, the generation of graphics is shifting to individuals who lack formal training in graphics design. This trend increases the possibility that poorly designed graphics will be used in decision-making. An experiment is reported that examined graphs that conformed to and which violated existing graphics standards regarding scaling in the context of financial forecasting. The experiment found that these specific violations of the scaling standards were tolerable when graphs were used for decision-making View full abstract»

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  • A frame architecture for a certain class of graph search problems

    Publication Year: 1988 , Page(s): 815 - 824
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (880 KB)  

    A frame control strategy is presented which directs an efficient graph search when information available for finding a path is distributed throughout the graph. The frame structure requires (worst case) only O(KN) memory size instead of O(K 2N), which is needed for a matrix representation of an N -level, K-branch tree graph. An efficiency analysis is detailed, and its application to a communication system for the nonverbal, severely motor disabled is discussed View full abstract»

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  • An analysis of four uncertainty calculi

    Publication Year: 1988 , Page(s): 700 - 714
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1504 KB)  

    An important issue faced by contemporary artificial intelligence workers is how to deal with uncertain information. Four of the more prominent calculi-probability theory (especially the Bayesian approach), the Dempster-Shafer theory, fuzzy set theory, and the MYCIN and EMYCIN calculi-are examined. Particular attention is paid to the underlying assumptions of these calculi and to their computational complexities. Each of the four calculi has a different perspective in uncertainty, and each manipulates uncertain information in a different way. Despite what some authors have claimed, there does not seem to be one calculus that is the best for all situations. Each of the calculi has its strong points; the main disadvantage seen in all of the calculi is that they compute aggregate numbers, but keep no record of divergence in opinions View full abstract»

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  • Approximate modeling of robots having elastic links

    Publication Year: 1988 , Page(s): 831 - 840
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    A method to derive approximate dynamic models is presented, which consists of a system of ordinary differential equations whose order, for a given robot, is related to the desired order of approximation. Such models are obtained by using the Lagrangian approach and by expanding in a limited number of terms the generalized coordinates describing the exact shape of the beams constituting the robot. A procedure is given that allows, if implemented on a computer, the automatic generation of the models. With such a procedure, by using the symbolic language MACSYMA, the models of one- and two-link flexible robots have been developed. Simulation tests to validate the proposed approximate model are included. These tests show that satisfactory results in terms of dynamic behavior of the approximate model are obtainable even with a reduced order of approximation View full abstract»

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  • Decision problem structuring: generating options

    Publication Year: 1988 , Page(s): 715 - 728
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1404 KB)  

    An integrative framework of methods for generating options for subsequent evaluation in a formal decision analysis is proposed. The overall process of decision problem structuring is briefly discussed. An associative network model of the way knowledge is represented cognitively is presented. Five categories of option-generating procedures are identified, including attribute-based, state-based, composite, option-based, and creativity techniques. The different option-generating procedures are seen as different strategies for traversing the cognitive network to search for and/or create options. The approaches differ by the type of cognitive unit (decision problem attribute, state, or option) to be brought into short-term memory to stimulate further search. Criteria for evaluating the sufficiency of the set of generated options are also presented. A discussion of future research directions is included View full abstract»

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  • An exact interactive method for exploring the efficient facets of multiple objective linear programming problems with quasi-concave utility functions

    Publication Year: 1988 , Page(s): 787 - 801
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1184 KB)  

    Many real-world problems can be formulated as multiple-objective linear programming (MOLP) problems. In the search for the best compromise solution for conflicting and noncommensurate objectives, a quasiconcave preference structure (utility function) is used that is more flexible and general than pseudoconcave, concave, and linear utility functions. Since the complete assessment of such a utility function is very difficult or impossible, an interactive method is developed in which, with a minimum of simple questions to the decision-maker (DM), the best compromise solution can be obtained. The DM responds to either paired comparison or simple trade-off questions. Conversion of tradeoff questions to paired comparison is discussed. The method also uses linear approximations of the nonlinear utility function to improve convergence rate. A procedure is provided for identifying efficient tradeoffs on the efficient facet so that only efficient alternatives are generated. Convergence with a limited number of questions is proven for quasiconcave and pseudoconcave utility functions View full abstract»

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  • Moment-by-moment variation in experts' analytic and intuitive cognitive activity

    Publication Year: 1988 , Page(s): 757 - 776
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1944 KB)  

    Moment-by-moment variation in the use of intuitive and analytical cognition by experts engaged in a complex judgment task is analyzed. Six highway engineers were asked to think aloud while producing formulas that expressed their knowledge of how highway aesthetics, safety, and capacity are determined by sets of relevant factors. Each engineer's statements were measured with multiple indices of the use of intuitive or analytical cognition, thus producing a moment-by-moment measure of the engineer's cognitive activity. Measures reflecting the rate of alternation between intuition and analysis, as well as patterns of change over time, were derived from this. The subtask the engineer was engaged in at each moment was also measured View full abstract»

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  • Human cognitive performance in antisubmarine warfare: situation assessment and data fusion

    Publication Year: 1988 , Page(s): 777 - 786
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    A cognitive simulation model of the antisubmarine warfare commander (ASWC) in a Naval Battle Group was developed, with particular emphasis on modeling his data fusion activities during situation assessment. These activities involve the estimation of enemy submarine tracks (position and velocity) and their likelihoods in a passive sonar convergence zone environment. The simulation is normative-descriptive in nature. A normative (optimal) mathematical model was first developed based on modern estimation and control theory. Experimental results with 20 experienced naval subjects on four scenarios, involving 12 contacts and three submarines each, indicated that the optimal or normative model always demonstrated superior performance to that of the human subjects. Known cognitive limitations and biases, drawn from the cognitive and behavioral sciences and/or directly observed in human subject performance, were then incorporated in the model View full abstract»

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  • Distributed Bayesian hypothesis testing with distributed data fusion

    Publication Year: 1988 , Page(s): 695 - 699
    Cited by:  Papers (48)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    The problem of distributed Bayesian hypothesis testing with distributed data fusion is examined. In the distributed data fusion configuration, some signal processing is done locally at the sensors and the partial results are transmitted to the other sensors for further processing and fusion. Global results are obtained at each of the sensors. This system configuration is attractive for many applications from the survivability point of view. The problem is formulated, and optimum decision rules and fusion schemes are obtained that minimize the Bayesian risk at each sensor. An example is presented for illustration View full abstract»

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  • Decision models for aiding FMS scheduling and control

    Publication Year: 1988 , Page(s): 744 - 756
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1240 KB)  

    Control of flexible manufacturing systems (FMS) requires the complex interaction of two components: (1) computers to perform automated control and routing activities, and (2) humans to supervise the automation, to monitor system flows and outputs, and to intervene to diagnose and either correct or compensate for unanticipated events. Current academic FMS scheduling research has focused mainly on the first component in the control loop, development of scheduling algorithms for optimization and control. Here, the second component is included in both the definition of the FMS control problem and the corresponding control approach. A more realistic definition of the FMS control environment is presented using a supervisory control framework. Within this context, the concept of aiding a human operator who supervises the predominantly automated FMS operations is developed View full abstract»

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  • Efficient scheduling algorithms for robot inverse dynamics computation on a multiprocessor system

    Publication Year: 1988 , Page(s): 729 - 743
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1168 KB)  

    The problem of scheduling the robot inverse dynamics computation consisting of m computational modules to be executed on a multiprocessor system consisting of p identical homogeneous processors to achieve a minimum-schedule length is examined. This scheduling problem is known to be NP-complete. To achieve the minimum computation time, the Newton-Euler equations of motion are expressed in the homogeneous linear recurrence form that results in achieving maximum parallelism. To speed up the searching for a solution, a heuristic search algorithm called dynamical highest-level-first/most-immediate-successors-first (DHLF/MISF) is proposed to find a fast but suboptimal schedule. For an optimal schedule the minimum-schedule-length problem can be solved by a state-space search method, the A* algorithm coupled with an efficient heuristic function derived from the Fernandez and Bussell bound View full abstract»

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