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Systems, Man and Cybernetics, IEEE Transactions on

Issue 1 • Date Jan/Feb 1989

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Displaying Results 1 - 20 of 20
  • On the trade-offs between the file redundancy and the communication costs in distributed database systems

    Publication Year: 1989 , Page(s): 108 - 112
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    The operating cost of distributed database systems (DDBS) usually depends on the storage costs of file copies, i.e file redundancy, and the communication cost of queries and for updates. A basic model is proposed to clarify the tradeoffs between the file redundancies and the communication cost of queries from the viewpoint of rate-distortion theory and its applications, for the case in which almost all requests are assumed to be queries. The result suggests that the addition of a few file copies is effective for the bus or ring network subsystems and the existence of only one file is essential to the star network subsystem, as the system size becomes large. The model leads to a useful measure for selecting the file-allocation design of a large scale DDBS View full abstract»

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  • Pool2: a generic system for cognitive map development and decision analysis

    Publication Year: 1989 , Page(s): 31 - 39
    Cited by:  Papers (40)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (792 KB)  

    The authors present Pool2, a generic system for cognitive map development and decision analysis that is based on negative-positive-neutral (NPN) logics and NPN relations. NPN logics and relations are extensions of two-valued crisp logic, crisp (binary) relations, and fuzzy relations, NPN logics and relations assume logic values in the NPN interval [-1, 1] instead of values in [0, 1]. A theorem is presented that provides conditions for the existence and uniqueness of heuristic transitive closures of an NPN relation. It is shown that NPN logic and NPN relations can be used directly to model a target world with a combination of NPN relationships of attributes and/or concepts for the purposes of cognitive map understanding, and decision analysis. Two algorithms are presented for heuristic transitive closure computation and for heuristic path searching, respectively. Basic ideas are illustrated by example. A comparison is made between this approach and others View full abstract»

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  • Continuing education in engineering

    Publication Year: 1989 , Page(s): 2 - 5
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    The author considers whether universities are equipped to provide continuing education in engineering. He discusses faculty commitment and institutional realignment at universities. He touches briefly on industry and government response View full abstract»

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  • Two approaches for information retrieval through fuzzy associations

    Publication Year: 1989 , Page(s): 123 - 130
    Cited by:  Papers (5)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB)  

    Two approaches for the formulation of information through fuzzy associations are presented. A fuzzy association is introduced as a fuzzy relation defined on a set of indices to a database. One approach is the extension of fuzzy indices to a database using fuzzy associations. A fuzzy association is a generalization of the concept of fuzzy thesauri. An algorithm for fuzzy information retrieval based on this approach is developed. The other approach represents the retrieval process as a block diagram. Maximum and minimum operations are used instead of the ordinary sum and product operations on the diagram. Studies of advanced indexing, such as the clustering of articles, are represented as feedback on the diagram. Properties of fuzzy information retrieval, such as level fuzzy sets and set operations on responses of the retrieval system, are discussed using the diagram representation View full abstract»

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  • Nonstationary composite modeling of images

    Publication Year: 1989 , Page(s): 112 - 117
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1020 KB)  

    Images are modeled as second-order nonstationary random fields, using a composite model that consists of a space-varying mean value function and a zero-mean nonstationary random field. The first component represents the underlying structure of an image, whereas the residual component provides the image's fine information. The authors develop space-varying estimators for the mean value and the variance functions and obtain conditions for such estimators to be statistically unbiased and consistent. The residual image component is modeled as an autoregressive system with space-varying coefficients. Identification of these coefficients is accomplished using a complete set of orthonormal basis functions to represent them. An efficient recursive procedure is proposed to solve the normal equations resulting from the minimum-mean square identification. Applications for the proposed modeling procedure can be found in the restoration and coding of images. Examples illustrating some aspects of the procedure and its application to image restoration are given View full abstract»

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  • Development and application of a metric on semantic nets

    Publication Year: 1989 , Page(s): 17 - 30
    Cited by:  Papers (160)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1344 KB)  

    Motivated by the properties of spreading activation and conceptual distance, the authors propose a metric, called distance, on the power set of nodes in a semantic net. Distance is the average minimum path length over all pairwise combinations of nodes between two subsets of nodes. Distance can be successfully used to assess the conceptual distance between sets of concepts when used on a semantic net of hierarchical relations. When other kinds of relationships, like `cause', are used, distance must be amended but then can again be effective. The judgements of distance significantly correlate with the distance judgements that people make and help to determine whether one semantic net is better or worse than another. The authors focus on the mathematical characteristics of distance that presents novel cases and interpretations. Experiments in which distance is applied to pairs of concepts and to sets of concepts in a hierarchical knowledge base show the power of hierarchical relations in representing information about the conceptual distance between concepts View full abstract»

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  • Filtering information from human experts

    Publication Year: 1989 , Page(s): 6 - 16
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1036 KB)  

    The authors propose a model, or filter, for debiasing opinions from multiple experts and combining them into a single consistent estimate of some variable of interest. A distinguishing feature of the approach consists of making the calibration of experts an integral part of filtering. This enables the filter to learn from previous experience with the experts. The theoretical development takes a Bayesian perspective, using B. de Finetti's notion of exchangeability (1964). Experimental results with a preliminary computer implementation of the filter show that its estimates are better than those from comparable filters that do not involve calibration View full abstract»

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  • Reorganization of historical data to support the analysis of organization's behavior

    Publication Year: 1989 , Page(s): 153 - 158
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    An approach to reorganizing the historical data of an organization, where the data are based on a concept of black box and protocol, is proposed. A data model containing two time variables to represent the cycle time of operations in the organization and the time length for behavior analysis is developed. Using this model, a database containing the data files of all protocols describing the input state and output state of the activities concerned and the numerical data files of the statistics of interactions between and/or among entities concerned can be created from historical data taken from the daily operational database. The evidence from a case study in a general teaching hospital shows that the approach can be implemented and used to support the analysis of an organization's behavior for management purposes View full abstract»

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  • Identifying nondominated alternatives with partial information for multiple-objective discrete and linear programming problems

    Publication Year: 1989 , Page(s): 95 - 107
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1124 KB)  

    The problem addressed is that of reducing the set of finite (discrete) multiple-criteria alternatives to a subset of alternatives based on three assumptions: that the (multiattribute) utility function is additive over attributes; that single-attribute functions are known; and that scaling constants are not known exactly but are specified by a set of linear equalities through interactions with the decision-maker (DM). Definitions, theories, and computationally efficient procedures are developed to determine whether an alternate is worthy of further consideration, should be eliminated, or is the most preferred alternative for the given partial information. The concepts of convex and tradeoff nondominancy are defined. All ensuing problems can be solved by linear programming. A computationally efficient algorithm is discussed. Other uses for the concepts developed are presented. It is shown that multiattribute discrete problems can be formulated as multiple-objective linear programming (MOLP) problems View full abstract»

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  • Group decision support with MOLP applications

    Publication Year: 1989 , Page(s): 143 - 153
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (904 KB)  

    Describes a group decision support system (GDSS) for a situation in which there are two groups of participants: a professional staff and the decision-makers (DMs). Through the participants' reciprocation and complementation, a three-step decision process utilizing a general multiple-objective linear programming (MOLP) model is designed. The three-steps are the generation of alternatives, the group-decision operation, and the evaluation of the final results. The GDSS is evaluated with respect to four criteria: complete information, full participation, equity principle, and economic decision time. On the basis of these criteria, the system has shown its potential to improve the quality of decision-making and to shorten the time required for the process View full abstract»

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  • Three-dimensional interpretation of perspective images

    Publication Year: 1989 , Page(s): 117 - 123
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB)  

    Quadrangle patterns are considered as the simplest closed figure that can provide 3D information from a 2D image. The necessary and sufficient conditions for the interpretation of perspective images are the existence of both images of a line in the space and a line projected orthographically on the base plane. Usually, these are not satisfied, and 3D information is recovered under appropriate assumptions. The following assumptions are proposed: a general viewpoint, a flat plane, the necessary condition for interpreting linear perspective, depth interpretation of the quadrangle, and the angle accommodation. The assumption of a flat plane has been examined by a psychophysical experiment. The results show that the existence of parallel line segments in the image plays an important role in the interpretation of perspective images View full abstract»

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  • Acceleration compensation for biped robots to reject external disturbances

    Publication Year: 1989 , Page(s): 74 - 84
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    The disturbance rejection problem associated with practical biped robots is studied. When the biped robot receives an external disturbance, robot joints suffer abrupt velocity changes. This causes angular velocity of the supporting angle (the angle between the supporting foot and ground) to deviate from 0°, which makes the robot unstable. To reject external disturbances, a strategy called acceleration compensation is proposed. This strategy uses joint accelerations to impose negative acceleration on the angular velocity of the supporting angle, i.e the acceleration is in the opposite direction to the angular velocity. The angular velocity acquired at the moment of a disturbance can thus be reduced to zero in a minimum amount of time, so the deviation of the supporting angle is minimized. Computer simulation and experimental results are presented that verify the usefulness of the method View full abstract»

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  • Mathematical classification of evoked potential waveforms

    Publication Year: 1989 , Page(s): 68 - 73
    Cited by:  Papers (6)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB)  

    It is shown that evoked potential waveforms can be classified into clinically significant patterns in computerised EEG analysis and other medical fields through application of a pattern-recognition technique which is presented. Fourier descriptors are used to characterize each waveform. Since the feature sets of Fourier descriptors contain information about the shape of the waveforms, they are used in the structural stage of the algorithm. In this stage, discriminant analysis is used to design a measure of dissimilarity between pairs of waveforms. Only the resulting interdistance matrix is preserved in the construction of the vector representation, making the dissimilarity measure crucial to the success of the remainder of the procedure. An algorithm using Fourier descriptors as feature vectors and the sum of squared error criterion to indicate improvement in percent of correctly classified waveforms has yielded accuracies of at least 90% View full abstract»

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  • Constraints identification in time-varying obstacle avoidance for mechanical manipulators

    Publication Year: 1989 , Page(s): 140 - 143
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB)  

    The time-varying obstacle avoidance problem is considered mathematically. The manipulator motion is described in terms of constrained motions, which are classified into two categories: the environmental constraints and the manipulator constraints. The constraints are converted into the reachable path segment at each servo time instant to verify the existence of a collision-free trajectory View full abstract»

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  • Correction procedures for flexible interpretive structural modeling

    Publication Year: 1989 , Page(s): 85 - 94
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (684 KB)  

    Flexible interpretive structural modeling (FISM) is an extended and improved version of the interpretive structural modeling developed by J.N. Warfield (1974). The computer algorithm of FISM is based on the partially filled reachability matrix (PR matrix) model, an extension of the reachability matrix (R matrix) model that has great utility in all phases of ISM. While an FISM structural model is being developed, or after it has been developed, the developer may want to make changes (corrections) in it. Several types of corrections for FISM are defined: change of one or more entries from zero to one; change of one or more entries from one to zero; deletion of one or more elements and their connections; and addition of one or more elements and their connections. Four tuned-up correction procedures are proposed to provide effective and consistent corrections. The correction procedures, along with the implication procedures for a PR-matrix, give a complete set of procedures for implementing FISM View full abstract»

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  • Semantic nets as paradigms for both causal and judgemental knowledge representation

    Publication Year: 1989 , Page(s): 58 - 67
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (900 KB)  

    The use of semantic nets to represent causation in static and dynamic processes is proposed. Their conventional usage as mechanisms for representing judgemental and experimental knowledge is reviewed. A specific semantic net called an M-labeled digraph is investigated with respect to its potential for evolving a more unified and holistic knowledge representation paradigm. A breadth-first inference engine utilizing Boolean multiplication of binary matrices is presented. Limitations of the method are discussed View full abstract»

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  • On the LU factorization of Hessenberg matrices

    Publication Year: 1989 , Page(s): 139 - 140
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    The LU factorization of the Hessenberg matrix is explicitly presented. The matrix is recognized for reliable and robust numerical computation View full abstract»

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  • Intelligent computer-aided instruction: a survey organized around system components

    Publication Year: 1989 , Page(s): 40 - 57
    Cited by:  Papers (7)  |  Patents (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1932 KB)  

    The issues and previous research in intelligent computer-aided instruction (ICAI) are surveyed, concentrating on the contribution of each effort to understanding the various components of ICAI systems. Comparisons are made between ICAI and CAI. Various learning scenarios are discussed including computer coaches, gaming environments, mixed initiative dialog, Socratic tutors, articulate experts, interactive simulation, and discovery learning. Various forms of knowledge representation are discussed along with relevant issues and examples. Several techniques for student modeling and diagnosis are presented, as are their respective advantages and disadvantages. Pedagogical knowledge, its role in ICAI and several examples are highlighted. The evolution of discourse-management techniques for ICAI is outlined. Techniques for the automatic generation of problems from a general base of domain knowledge are presented. The design of user interfaces for ICAI systems is briefly discussed View full abstract»

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  • Singularity of nonlinear feedback control scheme for robots

    Publication Year: 1989 , Page(s): 134 - 139
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    The author investigates the singular problem of a robot-control scheme with u sin θ as the orientation error, where u and θ are, respectively, the unit vector of the rotational axis and the rotational angle from the current orientation of the end effector to the desired one. It is rigorously found that the singularity points of the control scheme are at θ=±π/2 and ±π, and, for a step into θ, π/2<θ<π, the orientation error converges to θ=π instead of θ=0. Therefore, the applicable domain of the control scheme is only -π/2<θ<π/2. The theory is also verified by simulations run on the Stanford manipulator View full abstract»

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  • Error recovery: a condition-oriented replanning approach

    Publication Year: 1989 , Page(s): 130 - 134
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    Normally, a plan must be carried out in a world whose behavior cannot be predicted exactly, so that failures (or unexpected events) can occur during execution. A system that is capable of handling such failures is presented. The error recovery process consists of error detection, error identification, and plan repair. The problem of error identification has been solved by using the condition-oriented approach, which is the authors' central theme. Error classification is accomplished by checking the role of failed conditions in the plan. If all conditions in a plan are stored during the plan generation phase, the subplans that are affected by a failed condition can be easily located. Three error categories and the modification processes are described View full abstract»

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