Browsing by Author "Chung, CG"

Now showing 1 - 14 of 14

A behavior-based classification and retrieval technique for object-oriented specification reuse
(1996-07-01)
Chou, SC
;
Chen, JY
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
This paper presents a classification and retrieval technique for object-oriented specification reuse, based on the assumption that existing specifications exhibiting behaviors similar to that of the system under development are appropriate for reuse. Existing specifications are classified and retrieved according to the semantic networks abstracted from their behaviors. Since semantic networks attach semantic meanings to certain degrees of detail, our technique is rather precise. Primary behavior is used to classify specifications because it can be obtained in the early phases of system analysis. Therefore, our technique allows early reuse. Moreover, subspecifications and classes of existing specifications are classified independently so that they can be retrieved for reuse separately. Thus, our technique encourages reusing subspecifications as well as classes. Since a subspecification is composed of classes and their relationships, reusing it corresponds to reusing all those classes and relationships, A technique that reuses subspecifications as well as classes is thus expected to save more time than those that reuse only classes.
A behavior-based classification and retrieval technique for object-oriented specification reuse
(1996-07-01)
Chou, SC
;
Chen, JY
;
Chung, CG
;
交大名義發表
;
資訊工程學系
This paper presents a classification and retrieval technique for object-oriented specification reuse, based on the assumption that existing specifications exhibiting behaviors similar to that of the system under development are appropriate for reuse. Existing specifications are classified and retrieved according to the semantic networks abstracted from their behaviors. Since semantic networks attach semantic meanings to certain degrees of detail, our technique is rather precise. Primary behavior is used to classify specifications because it can be obtained in the early phases of system analysis. Therefore, our technique allows early reuse. Moreover, subspecifications and classes of existing specifications are classified independently so that they can be retrieved for reuse separately. Thus, our technique encourages reusing subspecifications as well as classes. Since a subspecification is composed of classes and their relationships, reusing it corresponds to reusing all those classes and relationships, A technique that reuses subspecifications as well as classes is thus expected to save more time than those that reuse only classes.
An enhanced zero-one optimal path set selection method
(1997-11-01)
Chung, CG
;
Lee, JG
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
One issue in structural program testing is how to select a mimimal set of test paths to meet certain test requirements. This is referred to as the optimal path set selection problem. The previously proposed zero-one optimal path set selection method is a generalized method that can be applied to most coverage criteria. However, the major drawback of this method is that for a large program the computation may take ten or more hours because the computation is exponentially proportional to the number of candidate paths and proportional to the number of components to be covered. To alleviate the drawback, this paper enhances the method by (1) defining five reduction rules, and (2) reusing previously selected path sets to reduce both the number of candidate paths and the number of components to be covered. Since both the number of candidate paths and the number of components to be covered are reduced, the computation time can be greatly reduced. In addition, an efficient approach to handling infeasible paths is proposed. An evaluation of the enhanced zero-one method, the original zero-one method, and a greedy method is executed and the result is presented. (C) 1997 Elsevier Science Inc.
An enhanced zero-one optimal path set selection method
(1997-11-01)
Chung, CG
;
Lee, JG
;
資訊工程學系
;
Department of Computer Science
One issue in structural program testing is how to select a mimimal set of test paths to meet certain test requirements. This is referred to as the optimal path set selection problem. The previously proposed zero-one optimal path set selection method is a generalized method that can be applied to most coverage criteria. However, the major drawback of this method is that for a large program the computation may take ten or more hours because the computation is exponentially proportional to the number of candidate paths and proportional to the number of components to be covered. To alleviate the drawback, this paper enhances the method by (1) defining five reduction rules, and (2) reusing previously selected path sets to reduce both the number of candidate paths and the number of components to be covered. Since both the number of candidate paths and the number of components to be covered are reduced, the computation time can be greatly reduced. In addition, an efficient approach to handling infeasible paths is proposed. An evaluation of the enhanced zero-one method, the original zero-one method, and a greedy method is executed and the result is presented. (C) 1997 Elsevier Science Inc.
An executable specification language for specification understanding in object-oriented specification reuse
(1996-06-01)
Chou, SC
;
Chen, JY
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
System analysis time can be reduced through specification reuse which, however, requires specification understanding. This paper presents an object-oriented executable specification language which reduces understanding time through executing specifications. In addition to being executable, the specification language hides as many classes as possible within subsystems, and explicitly specifies relationships between specification components. This facilitates specification modification. Moreover, the language explicitly specifies interface parameters of specification components. This facilitates specification composition.
An executable specification language for specification understanding in object-oriented specification reuse
(1996-06-01)
Chou, SC
;
Chen, JY
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
System analysis time can be reduced through specification reuse which, however, requires specification understanding. This paper presents an object-oriented executable specification language which reduces understanding time through executing specifications. In addition to being executable, the specification language hides as many classes as possible within subsystems, and explicitly specifies relationships between specification components. This facilitates specification modification. Moreover, the language explicitly specifies interface parameters of specification components. This facilitates specification composition.
An experience of using FDOOA method to develop a telecommunications network management system
(1998)
Hung, YS
;
Liu, WC
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
Most OOA methods ignore the importance of system functions that are the focus of users, and require an extra effort to remove the redundant classes introduced in identifying candidate classes from the norms and verbs of problem description To remedy these drawbacks, we proposed the FDOOA (Functional-Decomposition OOA) method. The system function model is introduced; the class model is constructed through a parallel decomposition of function and data and bottom-up composition to formulate a class hierarchy. We also design an executable specification language - AOORPL and a supporting environment to construct the rapid prototype automatically so that the user can validate the specification visually. To evaluate feasibility of the FDOOA method on large-scale software systems, we use a telecommunications network management system as example to define its system specification. This system includes 44 services in total, and its system specification has 112 system functions/subfunctions and 183 classes. After this evaluation, we indeed demonstrate the advantage of facilitating the communication,vith the users, reducing redundant classes, decreasing the cost of modifications, and simplifying the verification of requirement specifications.
An expert-system technique for object-oriented program testing
(1999-02-01)
Chen, WC
;
Chen, DJ
;
Chung, CG
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
Data abstraction, information hiding, inheritance, and dynamic binding are four basic elements used in designing object-oriented (OO) programs. These four mechanisms enable programmers to write object-oriented programs that are easily extended, reused and maintained. Software implemented by OO methodologies has increased software quality and productivity.(1) However, this cannot be guaranteed without an appropriate software testing approach. Traditional testing approaches cannot be applied directly to the testing of OO programs due to the OO characteristics used in these programs. OO program testing strategies and methods are proposed continually, but fewer OO testing tools with flexibility are discussed.
An optimal representative set selection method
(2000-01-15)
Lee, JG
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
The optimal representative set selection problem is defined thus: given a set of test requirements and a test suite that satisfies all test requirements, find a subset of the test suite containing a minimum number of test cases that still satisfies all test requirements. Existing methods for solving the representative set selection problem do not guarantee that obtained representative sets are optimal (i.e, minimal). The enhanced zero-one optimal path set selection method [C.G. Chung, J.G. Lee, An enhanced zero-one optimal path set selection method, Journal of Systems and Software, 39(2) (1997) 145-164] solves the so-caned optimal path set selection problem, and can be adapted to solve the optimal representative set selection problem by considering paths as test cases and components to be covered (e.g. branches) as test requirements. (C) 2000 Elsevier Science B.V. All rights reserved.
iNetwork - a GSM compliant IF-based communication platform
(2000)
Cheng, CW
;
Liu, WC
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
Enterprise communication systems require data, voice, and mobile communication services. However, the cost to maintain many disparate networks is high. We propose iNetwork, an IF-based communication system complied with GSM to provide these services at an integrated platform Furthermore, an iNetwork system can cooperate with other iNetwork, Internet, PSTN or GSM systems to provide global services.
Path-based protocol verification approach
(2000-03-01)
Liu, WC
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
Protocol verification is one of the most challenging tasks in the design of protocols. Among the various proposed approaches, the one based on reachability analysis (or known as state enumeration approach) is of the most: simple, automatic and effective. However, the state explosion problem is a principle obstacle toward successful and complete verifications of complex protocols. To overcome this problem, we proposed a new approach, the "path-based approach." The idea is to divide a protocol into a collection of individual execution record, denoted as: concurrent paths, a partial order representation recording the execution paths of individual entities. Then, the verification of the protocol is, thus, replaced by that of individual concurrent paths. Since concurrent paths can be automatically generated through Cartesian product:of the execution paths of all modules, and verified independently, the memory requirement is limited to the complexity of individual concurrent path rather than the whole protocol. Thus, the state explosion problem is alleviated from such "divide and conquer" approach. Furthermore, we propose an algorithm, making the trade-off on memory requirement to generate the concurrent paths more efficiently; and utilize the technique of symmetric verification, parallel computing to improve the efficiency of verification. Eventually, our experience of verifying real protocols shows that our approach uses much less memory:and time than reachability analysis. (C) 2000 Elsevier Science B.V. All rights reserved.
Symbolic path-based protocol verification
(2000-03-01)
Liu, WC
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
The principal problem in protocol verification is state explosion problem. In our work (W.C. Liu, C.G. Chung, Path-based Protocol Verification Approach, Technical Report, Department of Computer Science and Information Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan, ROC, 1998), we have proposed a "divide and conquer" approach to alleviate this problem, the path-based approach. This approach-separates the protocol into a set of concurrent paths, each of which can be generated and verified independently of the others. However, reachability analysis is used to identify the concurrent paths from the Cartesian product of unit paths, and it is time-consuming. Therefore,:in this paper, we propose a simple and efficient checking algorithm-to identify the concurrent paths from the Cartesian product, using only Boolean and simple arithmetic operations. (C) 2000 Elsevier Science B.V; All rights reserved.
The design of a signaling system in an enterprise network system
(2003)
Cheng, CW
;
Liu, WC
;
Chung, CG
;
資訊工程學系
;
Department of Computer Science
An enterprise communication system has the requirements of data, voice, and mobile communications. We have proposed iNetwork as an enterprise-based communication system that integrates GSM services and IP network resources to establish a low cost communication environment. In this paper we discuss the design of signaling system in iNetwork system, and study the performance and efficiency of iNetwork by investigating the call setup time and mis-routing events. The resultant design has less routing stages than the original design of GSM and it can avoid bandwidth wastage and enhances the utilization of network resources.
Utilizing 3G/WLAN dual-mode terminals to enhance the efficiency of mobile number portability service
(2006-06-01)
Cheng, CW
;
Chung, CG
;
交大名義發表
;
National Chiao Tung University
Querying routing information is all-call-based during the process of translating portable numbers. Long delays in database searches make portable number translation the bottleneck of providing mobile number portability (NP) service. In this article we propose the mitigation of the traffic load through querying an NP database (NPDB) to alleviate the portable number translation delay. We also present a mechanism that utilizes the routing information on dual-mode MSs to alleviate the traffic load of NPDB and thus enhances the efficiency of mobile NP service. To conclude, we evaluate the performance of the proposed mechanism by simulation.