Browsing by Author "HWANG, GJ"

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A FIBEROPTIC REFLECTIVE DISPLACEMENT MICROMETER
(1995-06-01)
KO, WH
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CHANG, KM
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HWANG, GJ
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交大名義發表
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National Chiao Tung University
A simple fiber-optic reflection displacement micrometer with a sensitivity of 200 mV mu m(-1) and a resolution as low as 0.01 mu m is reported with a theoretical explanation of the experimental results. The sensor consists of a pulsed LED light source and a pair (A and B) of identical receiving fibers and photodetectors that detects the light reflected from the surface being measured. The differential signal (A-B) of the detectors is proportional to the displacement of the surface relative to a null position. The light intensity variation of the source and the reflectance change of the surface are compensated when the (A-B) signal is divided by the sum (A+B). The resolution is limited by noise and interference (vibration of the base). A resolution of 0.01 mu m can be achieved at narrow signal bands (d.c, to 3 Hz) excluding the low-frequency noise and vibration. The range, sensitivity and non-linearity can be adjusted according to the theory. The micrometer offers the advantages of non-contact, no electrical interference, simplicity, low cost and portability. It can be used in medical experiments and laboratory instruments.
A HEURISTIC TASK ASSIGNMENT ALGORITHM TO MAXIMIZE RELIABILITY OF A DISTRIBUTED SYSTEM
(1993-09-01)
HWANG, GJ
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TSENG, SS
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資訊工程學系
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Department of Computer Science
Distributed systems potentially provide high reliability owing to the program and data-file redundancy possible. In many applications, high reliability is the major consideration for system design. Some work by Kumar, Hariri, Raghavendra shows that the distribution of programs and data-files can affect the system reliability appreciably, and that redundancy in resources such as computers, programs, and data-files can improve the reliability of distributed system. This paper first formulates a practical application for a reliability-oriented distributed task assignment problem which is NP-hard. Then, to cope with this challenging problem, we propose a greedy algorithm, based upon some heuristics, to find an approximate solution. The simulation shows that, in most cases tested, the algorithm finds suboptimal solutions efficiently; therefore, it is a desirable approach to solve these problems.
DEVELOPMENT AND ANALYSIS OF A NETWORK-BASED MULTI-MEDIA TOUR GUIDING SYSTEM
(1993)
CHEN, FR
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HWANG, GJ
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資訊工程學系
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Department of Computer Science
KNOWLEDGE ACQUISITION FOR FUZZY EXPERT-SYSTEMS
(1995-06-01)
HWANG, GJ
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
;
Department of Computer Science
Expert systems have been successfully applied to a wide variety of application domains. To achieve better performance, researchers have tried to employ fuzzy logic to the development of expert systems. However, as fuzzy rules and membership functions are difficult to define, most of the existing tools and environments for expert systems do not support fuzzy representation and reasoning. Thus, it is time-consuming to develop fuzzy expert systems. In this article we propose a new approach to elicit expertise and to generate knowledge bases for fuzzy expert systems. A knowledge acquisition system based upon the approach is also presented, which can help knowledge engineers to create, adjust, debug, and execute fuzzy expert systems. Some control techniques are employed in the knowledge acquisition system so that the concepts of fuzzy logic could be directly applied to conventional expert system shells; moreover, a graphic user interface is provided to facilitate the adjustment of membership functions and the display of outputs. The knowledge acquisition system has been integrated with a popular expert system shell, CLIPS, to offer a complete development environment for knowledge engineers. With the help of this environment, the development of fuzzy expert systems becomes much more convenient and efficient. (C) 1995 John Wiley & Sons, Inc.
RELIABILITY-ORIENTED SYSTEM DESIGN AND ANALYSIS ON COMPUTER NETWORKS
(1993)
TSAI, WJ
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HWANG, GJ
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資訊工程學系
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Department of Computer Science