Browsing by Author "CHUNG, CG"

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A KNOWLEDGE-BASED OPERATION SUPPORT SYSTEM FOR NETWORK TRAFFIC MANAGEMENT
(1994-01-01)
CHANG, CY
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CHUNG, CG
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交大名義發表
;
National Chiao Tung University
The operation of a telephone network is subject to unexpected contingencies such as facilities impairments, trunk congestion, and focused overload. When contingencies happen in the network, the proper control actions must be taken promptly within a short period of time (e.g. 5 minutes); otherwise, the serious congestion will soon spread to the other parts of network. Until now, there has been a lack of an automated approach to generate a contingency routing plan to prevent network degradation. In this paper, a knowledge-based traffic control support system (TRACOSS) is proposed for network traffic management. TRACOSS not only contains four knowledge bases to accumulate the domain expertise used for contingencies detection, diagnosis, affected traffic estimation and control commands generation, but also contains a multicommodity network flow model to formulate the operation of telephone network. Based on this model, a heuristic algorithm is developed to design the contingency routing plan. TRACOSS has the following advantages: (1) The acceptable contingency plan can be obtained by the heuristic algorithm within the fixed time constraint. (2) Four knowledge bases can be used to accumulate the domain expertise to automate the network traffic management. (3) When new network components are installed, knowledge bases can be easily upgraded to adapt new technologies.
A STRUCTURAL TESTING METHOD FOR C++ PROGRAMS
(1994)
LEE, JG
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FENG, MJ
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CHUNG, CG
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資訊科學與工程研究所
;
Institute of Computer Science and Engineering
ADAPTIVE TRACKING SYSTEM FOR A MANEUVERING TARGET USING IMAGES WITH CORRELATED NOISES
(1989-05-01)
CHANG, KC
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LEE, HJ
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CHUNG, CG
;
交大名義發表
;
資訊工程學系
AN EFFICIENT APPROACH TO REAL-TIME TRAFFIC ROUTEING FOR TELEPHONE NETWORK MANAGEMENT
(1994-02-01)
CHANG, CY
;
CHUNG, CG
;
交大名義發表
;
National Chiao Tung University
When contingencies occur in the telephone network the proper traffic control actions for rearranging the traffic flow must be promptly taken in a short period of time, otherwise, the congestion will soon spread to other parts of the network. In this paper, a multicommodity maximal flow model is proposed to formulate the problem, and an efficient approach is proposed to find the solution within a short time period. The node pairs are first sorted by the traffic demand into decreasing order and the capacity of links is allocated to the node pair with largest demand. The traffic allocation is then iteratively reallocated on those routes which share the same links to find a better solution, until that solution is obtained. The advantages of this approach are: (1) a feasible solution can be obtained within a short time period; (2) the affected traffic can be rerouted on paths with more than two links; (3) an acceptable solution can be found once the period has expired.
AN OBJECT-ORIENTED MODELING APPROACH TO SYSTEM SOFTWARE-DESIGN
(1994-11-01)
LEE, FPJ
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CHEN, DJ
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CHUNG, CG
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資訊科學與工程研究所
;
Institute of Computer Science and Engineering
In this paper, a modelling method entitled MOOD (Modelling approach to Object-Oriented Design) is proposed for the design of object-oriented system software. The method employs entity-refinement, functional modelling, and object modelling techniques to model the world of solution-domain objects. The modelling result based on MOOD forms a set of graphic notations that describe the structure, functions, and client-server relationships among the entities. These graphic notations can be mapped directly into object-oriented programming constructs during the implementation phase. MOOD devotes special attention to the reuse of existing components or newly designed components for future reuse. Unlike other methods, which find objects from textural statements, the entity-refinement approach proposed here can identify all the entities and their operations within the solution domain. MOOD is compared with existing methods to show its feasibility and uniqueness.
DIGITALIZATION OF CONTINUOUS-DATA SYSTEMS VIA TIME-RESPONSE MATCHING
(1982)
CHUNG, CG
;
HAN, KW
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YEH, HH
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資訊工程學系
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Department of Computer Science
MANEUVERING TARGET TRACKING IN A CLUTTERED ENVIRONMENT FROM NOISY IMAGES BY AN ADAPTIVE PROBABILISTIC DATA ASSOCIATION FILTER
(1991-01-01)
LEE, HJ
;
CHUNG, CG
;
CHANG, KC
;
交大名義發表
;
資訊工程學系
A new tracking method for estimating motion parameters of a manoeuvring target in a cluttered environment from noisy image sequences is presented. Traditionally, tracking systems have been broadly classified according to (1) moving target with or without manoeuvring, and (2) tracking in a clean (uncluttered) or cluttered environment. The difficulties studied here are those arising from (a) unknown acceleration inducing a randomly updated trajectory, and (b) the disturbance of returns from false alarms or other interfering objects. The probability data association filter (PDAF) is augmented by the semi-Markov process, called the adaptive PDAF, to handle the difficulties. Since the acceleration state applied either by a pilot or by a guidance control system is independent of the appearance of false returns, the treatment of target manoeuvring and false returns are separated into two sub-problems, i.e. the PDAF is applied to govern the disturbance of multiple returns and the semi-Markov process is applied to estimate uncertain accelerations. Three simulation results of variations show small biases from the true trajectory. By comparing with a nearest neighbour standard filter, the proposed tracking system also demonstrates better results.
MANY-SORTED 1ST-ORDER LOGIC DATABASE LANGUAGE
(1992-04-01)
YANG, JSH
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CHIN, YH
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CHUNG, CG
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資訊科學與工程研究所
;
Institute of Computer Science and Engineering
A database languages based on Many-Sorted First-Order Logic (MSFOL) have many, advantages over one based on One-Sorted First-Order Logic (OSFOL). The advantages includes ease-of-expressiveness, efficiency, and the abstraction mechanism. Many database researchers have used OSFOL to view the Relational Data Model (RDM); however, no RDM has been modelled by MSFOL. This paper first gives a formal definition for MSFOL and then its advantages of expressiveness and of abstraction are illustrated. Two reduction algorithms which can transform an MSFOL-based language into/from an OSFOL-based language are given. The semantic equivalence between languages based on MSFOL and Typed OSFOL is also proved. Recent extensions of RDMs require aggregation, classification, and generalisation/specialisation mechanisms which MSFOL-based languages can provide, but OSFOL-based languages cannot.
PATH-ANALYSIS TESTING OF CONCURRENT PROGRAMS
(1992-01-01)
YANG, RD
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CHUNG, CG
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資訊工程學系
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Department of Computer Science
Path analysis testing is a widely used approach to program testing. However, the conventional path analysis testing method is designed specifically for sequential program testing; it is inapplicable to concurrent program testing because of the existence of multi-loci of control and task synchronizations. A path analysis approach to concurrent program testing is proposed. A concurrent path model is presented to model the execution behaviour of concurrent programs. In the model, an execution of a concurrent program is seen as involving a concurrent path (which is comprised of the paths of all concurrent tasks), and the tasks' synchronizations are modelled as a concurrent route to traverse the concurrent path involved in the execution. Accordingly, testing is a process to examine the correctness of each concurrent route along all concurrent paths of concurrent programs. Examples are given to demonstrate the effectiveness of path analysis testing for concurrent programs and some practical issues of path analysis testing, namely, test path selection, test generation, and test execution, are discussed. Moreover, the errors of concurrent programs are classified into three classes: domain errors, computation errors, and missing path errors, similar to the error classification for sequential programs. Based on the error classification, the potential reliability of path analysis testing for concurrent programs is assessed.
PREVENTIVE STRUCTURAL-ANALYSIS OF DATA-FLOW DIAGRAMS
(1992-02-01)
CHEN, MJ
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CHUNG, CG
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交大名義發表
;
資訊科學與工程研究所
;
National Chiao Tung University
Editors for dataflow diagrams (DFDs) perform structural analysis conventionally after structural errors have been introduced into DFDs. This is a corrective approach to eliminating structural errors. However, cross-examining voluminous DFDs to fix structural errors is time-consuming and frustrating. The paper proposes a preventive approach to structural analysis. The approach associates structural checking with editing operators so that editing operations that will introduce structural errors into DFDs are inhibited. As not all of the structural errors can be prevented, a decision on which structural errors can/should be prevented must be made. Consideration of two factors is suggested: the characteristics of structural errors and the construction method(s) for DFDs. Both considerations are demonstrated. A set of editing operators that enforce the prevention is then proposed and specified.
RAPID PROTOTYPING FROM STRUCTURED ANALYSIS - EXECUTABLE SPECIFICATION APPROACH
(1990-11-01)
LEA, RJ
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CHUNG, CG
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資訊工程學系
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Department of Computer Science
RELIABILITY MODELING OF PARALLEL PROGRAMS WITH MODULAR STRUCTURE USING STOCHASTIC PETRI NETS
(1991-10-01)
HO, TF
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CHAN, WC
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CHUNG, CG
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資訊工程學系
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Department of Computer Science
Concurrent programming is witnessing a trend toward greater use of multiprocessing and distributed systems. However, the problem of reliability estimation for parallel programs has not yet been addressed. This article presents a methodology for software reliability estimation for parallel programs with modular structure. In deriving a model, the failure behavior of the parallel program is described by a stochastic Petri net. The reliability of the parallel program is calculated in terms of the relative frequencies of the failure events that are determined from simulation results of the stochastic Petri net model. An attractive feature of the proposed method is that the integration testing phase is not required for the estimation of reliability of the program. Therefore, the proposed method can be useful in an early phase of the software development process. An example is presented to illustrate the applicability of the proposed method.
RESTRUCTURING OPERATIONS FOR DATA-FLOW DIAGRAMS
(1991-07-01)
CHEN, MJ
;
CHUNG, CG
;
交大名義發表
;
資訊科學與工程研究所
;
National Chiao Tung University
When defining and designing software with structured analysis and design methods, we need to restructure data-flow diagrams. Using basic editing operations to restructure large systems with voluminous data-flow diagrams is tedious, laborious and error-prone. It is necessary to have data-flow diagram editors that provide editing operations specific for restructuring. This paper proposes and formally specifies a set of operations sufficient for all restructuring needs. It also confirms that the properties of consistency and completeness are observed by all the restructuring operations, and that both models of data-flow diagrams are equivalent, before and after each of the restructuring operations.
SIMPLIFICATION AND IDENTIFICATION OF DISCRETE TRANSFER-FUNCTION VIA STEP-RESPONSE MATCHING
(1981)
CHUNG, CG
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HAN, KW
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YEH, HH
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資訊工程學系
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Department of Computer Science