Browsing by Author "Yang, WP"

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A classification tree based on discriminant functions
(2006-05-01)
Chien, BC
;
Lin, JY
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
The classification problem is an important topic in knowledge discovery and machine learning. Traditional classification tree methods and their improvements have been discussed widely. This work proposes a new approach to construct decision trees based on discriminant functions which are learned using genetic programming. A discriminant function is a mathematical function for classifying data into a specific class. To learn discriminant functions effectively and efficiently, a distance-based fitness function for genetic programming is designed. After the set of discriminant functions for all classes is generated. a classifier is created as a binary decision tree with the Z-value measure to resolve the problem of ambiguity among discriminant functions. Several popular datasets from the UCI Repository were selected to illustrate the effectiveness of the proposed classifiers by comparing with previous methods. The results show that the proposed classification tree demonstrates high accuracy on the selected datasets.
A new storage and retrieval method to support editing operations in a multi-disk-based video server
(1996)
Lee, CI
;
Chang, YI
;
Yang, WP
;
交大名義發表
;
資訊工程學系
Since the storage ordering is assumed the same ns the retrieval ordering in all the previous storage placement strategies, there is a requirement of a large amount of file copying or merging operations when users insert/delete some data into/from the media data. The observation is also important for video applications because features, like video editing, require the support of random access on individual video frames. fn this paper, roe propose a new strategy for the insert/delete operations on continuous media that are striped into multi- disks without reorganization of the whole data. From our performance analysis and simulation, the proposed algorithms for insertion/deletion may require only some additional movement cost.
A new subliminal channel based on Fiat-Shamir's signature scheme
(1995-11-01)
Chen, CY
;
Chang, CC
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
This paper constructs a subliminal channel in a RSA-like variant of the Fiat-Shamir signature scheme to transfer any secret information. The proposed subliminal channel, unlike that in El-Gamal signature scheme, can avoid the serious shortcoming that a subliminal receiver can undetectably forge a signer's signature. In addition, our channel also overcomes almost all shortcomings from which the subliminal channel in El-Gamal signature scheme suffer.
A new subliminal channel based on Fiat-Shamir's signature scheme
(1995-11-01)
Chen, CY
;
Chang, CC
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
This paper constructs a subliminal channel in a RSA-like variant of the Fiat-Shamir signature scheme to transfer any secret information. The proposed subliminal channel, unlike that in El-Gamal signature scheme, can avoid the serious shortcoming that a subliminal receiver can undetectably forge a signer's signature. In addition, our channel also overcomes almost all shortcomings from which the subliminal channel in El-Gamal signature scheme suffer.
A note on consensus on dual failure modes
(1996-03-01)
Siu, HS
;
Chin, YH
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
Meyer and Pradhan proposed the MS (for ''mixed-sum'') algorithm to solve the Byzantine Agreement (BA) problem with dual failure modes: arbitrary faults (Byzantine faults) and dormant faults (essentially omission faults and timing faults) [3]. Our study indicates that this algorithm uses an inappropriate method to eliminate the effects of dormant faults and that the bound on the number of allowable faulty processors is overestimated. This paper corrects the algorithm and gives a new bound for the allowable faulty processors.
A novel application of the phone card and its authentication in mobile communications
(1999-07-01)
Lee, CH
;
Hwang, MS
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
The Subscriber Identity Module (SIM) is conventionally used in wireless communication systems. However, several limitations involving SIM significantly reduce public access in wireless communications. This study examined the feasibility of using public telephone cards in wireless communications. This novel application retains the merits of SIM. Among the relevent issues addressed are location tracking of the user, authentication of the phone card, and the billing scheme. Moreover, two implementations of phone card authentication are presented.
An access control scheme based on Chinese remainder theorem and time stamp concept
(1996)
Hwang, MS
;
Tzeng, WG
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In this paper we propose a new dynamic access control method for the computer system with frequently inserted, deleted and updated users/files. Our method, based on the concepts of the access control matrix, key-lock-pair, time stamp and Chinese remainder theorem, associates each user with a user key and a user lock and each tile with a file key and a file lock Our method can achieve the following four goals. (1) By a simple module operation on the keys and locks of the user and the file, we can reveal the access right of a user to a file. (2) When a user/file is added to the computer system, we only assign a key and a lock to the user/file without affecting the keys and locks of the other users/files in the system. (3) When a user/file is deleted from the computer system, we simply erase the entry of the user/file in the computer system. (4) When the access right of a user to a file is updated, we merely modify the key and lock of the user or the file without affecting the keys and locks of the other users/files in the system. The main contribution of our method is that the action of inserting, deleting a user/file, or updating the access right of a user to a file can be done by modifying only one key and one lock, which could not be achieved simultaneously before.
An adaptive value-based scheduling policy for multiprocessor real-time database systems
(1997)
Tseng, SM
;
Chin, YH
;
Yang, WP
;
交大名義發表
;
資訊工程學系
In a real-time application, a transaction may be assigned a value to reflect the profit of completing the transaction before its deadline. Satisfying both goals of maximizing the totally obtained profit and minimizing the number of missed transactions at the same time is a challenge. In this paper we present an adaptive real-time scheduling policy named Value-based Processor Allocation (VPA-k) for scheduling value-based transactions in a multiprocessor real-time database system. Using VPA-k policy, the transactions with higher values are given higher priorities to execute first, while at most k percentage of total processors are dynamically allocated to execute the urgent transactions. Through simulation experiments, VPA-k is shown to outperform other scheduling policies substantially in bath maximizing the totally obtained profit mid minimizing the number of missed transactions under various system environments.
An efficient conflict-resolution approach to support read/write operations in a video server
(1997-09-01)
Lee, CI
;
Chang, YI
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose an efficient conflict-resolution approach based on the multi-disk architecture for the insertion/deletion operations on continuous media that are split up into blocks and placed in various locations on the disk, without reorganizing the whole data. When a new subobject is inserted after subobject i, it will be assigned with an identification number (i+1) and be inserted into a disk in which the retrieval of the new subobject does not conflict with the retrieval of any other subobject, where a conflict means a pair of two consecutive subobjects that are stored in the same disk have to be retrieved simultaneously However, a new conflict on the same disk may occur since all the identification numbers of subobjects after subobject i are increased by one. Only when such a new conflict occurs, one movement operation is required, so does the case of a deletion operation. Moreover, to reduce those additional movement cost, a deferring approach is proposed at the cost of an additional buffer. In this approach, n data insertions are deferred and stored in a buffer. Then, the system starts to insert those data after an optimal insertion sequence is determined. Based on this approach, two strategies are proposed: the conflict-resolved-first-deferring strategy (the CRFD strategy) and the conflict-resolved-last-deferring strategy (the CRLD strategy). From our performance analysis, we will prove that the CRLD strategy with an insertion sequence according to the ascending order of identification numbers is an optimal strategy based on the proposed deferring approach.
An efficient conflict-resolution approach to support read/write operations in a video server
(1997-09-01)
Lee, CI
;
Chang, YI
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose an efficient conflict-resolution approach based on the multi-disk architecture for the insertion/deletion operations on continuous media that are split up into blocks and placed in various locations on the disk, without reorganizing the whole data. When a new subobject is inserted after subobject i, it will be assigned with an identification number (i+1) and be inserted into a disk in which the retrieval of the new subobject does not conflict with the retrieval of any other subobject, where a conflict means a pair of two consecutive subobjects that are stored in the same disk have to be retrieved simultaneously However, a new conflict on the same disk may occur since all the identification numbers of subobjects after subobject i are increased by one. Only when such a new conflict occurs, one movement operation is required, so does the case of a deletion operation. Moreover, to reduce those additional movement cost, a deferring approach is proposed at the cost of an additional buffer. In this approach, n data insertions are deferred and stored in a buffer. Then, the system starts to insert those data after an optimal insertion sequence is determined. Based on this approach, two strategies are proposed: the conflict-resolved-first-deferring strategy (the CRFD strategy) and the conflict-resolved-last-deferring strategy (the CRLD strategy). From our performance analysis, we will prove that the CRLD strategy with an insertion sequence according to the ascending order of identification numbers is an optimal strategy based on the proposed deferring approach.
An efficient dynamic threshold scheme
(1996-07-01)
Hwang, SJ
;
Chang, CC
;
Yang, WP
;
交大名義發表
;
資訊工程學系
To improve the efficiency for the threshold schemes, the major problem is that the secret shadows cannot be reused after renewing or recovering the shared secret. However, if the secret shadows cannot be reused, the established threshold scheme is limited to be used only once. It is inefficient to reconstruct the whole secret sharing system. Therefore, we introduce an efficient dynamic threshold scheme. In the new scheme, the shadowholders can reuse the secret shadows no matter that the shared secret is renewed or recovered. In addition, the new scheme provides a way by which the dealer can renew the shared secret or reconstruct the secret sharing system, efficiently. Therefore, this scheme is good for maintaining the important secrets.
An improvement of mobile users authentication in the integration enviromnents
(2002)
Hwang, MS
;
Lee, CC
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
This paper shows that Tzeng and Tzeng's protocol has a drawback that the protocol can be easily crashed by an evil VLR attack. Therefore, we propose a slight modification to their protocol to improve their shortcoming. As a result, our protocol does not only enhance the security of Tzeng and Tzeng's protocol but also improves the efficiency.
An improvement on the Lin-Wu (t, n) threshold verifiable multi-secret sharing scheme
(2005-04-05)
Chang, TY
;
Hwang, MS
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
Lin and Wu [IEE Proc. Comput. Digit. Tech. 146 (1999) 264] have proposed an efficient (t, n) threshold verifiable multi-secret sharing (VMSS) scheme based on the factorization problem and the discrete logarithm modulo a large composite problem. In their scheme, the dealer can arbitrarily give any set Of multiple secrets to be shared, and only one reusable secret shadow is to be kept by every participant. On the other hand, they have claimed that their scheme can provide an efficient solution to the cheating problems between the dealer and any participant. However, He and Wu [IEE Proc. Comput. Digit. Tech. 148 (2001) 139] have shown that Lin and Wu's scheme is in fact insecure against a cheating participant. In this paper, we shall try to improve the security of Lin and Wu's scheme while providing more efficient performance than other VMSS schemes in terms Of computational complexity. (C) 2004 Elsevier Inc. All rights reserved.
An object model at conceptual level to support updatable views on object-oriented databases
(1996-11-01)
Pan, WW
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
The research on view mechanisms for object-oriented databases can be classified into two independent issues, languages to define views and the underlying object models. This paper presents an object model at the conceptual level of abstraction. We call it the view class and real-world object model (V-R model). The major goal of the V-R model is intended to support updatable views efficiently for the object-oriented database systems. The V-R model elaborates a special method to describe the instance-of relationship between stored objects and classes so that a stored object can be the instance of several classes simultaneously. Query results and views can be managed like classes without creating temporary objects or tuples since the V-R model is closed against query operations. In this way, updates on views can be supported easily. This paper also explores the update semantics in depth. By utilizing the specialty of the V-R model, a more eligible update translation is proposed for the updates on classes with or without inheritance relationships and for the updates on views. To show that the V-R model is not only theoretical, how to implement the V-R model and how to integrate the V-R model into an object-oriented database system are illustrated. (C) Elsevier Science Inc. 1996
Authenticated encryption schemes with message linkage
(1996-05-27)
Hwang, SJ
;
Chang, CC
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
Authenticated encryption schemes need redundancy schemes to link up the message blocks; however, these redundancies increase communication costs. To construct links without increasing communication costs, we propose a general solution for all the authenticated encryption schemes based on the discrete logarithm problem. Because the computation cost to construct links is small, the improved scheme adopting our solution is almost as efficient as the original one, Moreover, by our solution, the recipient can easily determine the missing message blocks, and then acknowledge the sender to send only these blocks again. The communication cost will be also reduced. Adopting our solution, we also propose two new authenticated encryption schemes with message linkage.
Authenticated encryption schemes with message linkage
(1996-05-27)
Hwang, SJ
;
Chang, CC
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
Authenticated encryption schemes need redundancy schemes to link up the message blocks; however, these redundancies increase communication costs. To construct links without increasing communication costs, we propose a general solution for all the authenticated encryption schemes based on the discrete logarithm problem. Because the computation cost to construct links is small, the improved scheme adopting our solution is almost as efficient as the original one, Moreover, by our solution, the recipient can easily determine the missing message blocks, and then acknowledge the sender to send only these blocks again. The communication cost will be also reduced. Adopting our solution, we also propose two new authenticated encryption schemes with message linkage.
Business agent
(2002)
Meng, IH
;
Yang, WP
;
Chen, WC
;
Chang, LP
;
資訊工程學系
The Internet and World Wide Web represent an increasingly important channel for retail commerce as well as business transactions. However, there are almost 5 billion pages or sites on the Internet and WWW. There lacks an integrated mediator business agent which is around the internet to connect between suppliers and users. Therefore, an intelligent business broking agent between supply and demand is needed for using and sharing the information efficiently and effectively. In this paper we proposed a new business agent architecture. The Business Spy Agent (BSA) captures the supply and demand information from e-commence sites automatically. Supply and Demand Analysis Mechanism (SDAM) uses NLP technologies to extract product and trading information. Domain ontology is used to classify between supply and demand and to divide them into subsets. A benefit model is proposed to handle the pairing between sub-supply and sub-demand. And a divide-and-conquer algorithm is proposed to handle the whole matching between supply and demand. In the negotiation process, the architecture uses NLP and template to produce negotiation text to handle negotiation through mail. Finally, Hidden Business Mining Mechanism (HBMM) adopts data mining technology to achieve hidden business mining. The architecture covers the four process of buying behavior including support and need identification, Product brokering, Merchant brokering, Negotiation.
Byzantine agreement in the presence of mixed faults on processors and links
(1998-04-01)
Siu, HS
;
Chin, YH
;
Yang, WP
;
資訊工程學系
;
Department of Computer Science
In early stage, the Byzantine agreement (BA) problem was studied with single faults on processors in either a fully connected network or a nonfully connected network. Subsequently, the single fault assumption was extended to mixed faults (also referred to as hybrid fault model) on processors. For the case of both processor and link failures, the problem has been examined in a fully connected network with a single faulty type, namely an arbitrary fault. To release the limitations of a fully connected network and a single faulty type, the problem is reconsidered in a general network. The processors and links in such a network can both be subjected to different types of fault simultaneously. The proposed protocol uses the minimum number of message exchanges and can tolerate the maximum number of allowable faulty components to make each fault-free processor reach an agreement.
Chinese text summarization using a trainable summarizer and latent semantic analysis
(2002)
Yeh, JY
;
Ke, HR
;
Yang, WP
;
資訊工程學系
;
圖書館
In this paper, two novel approaches are proposed to extract important sentences from a document to create its summary. The first is a corpus-based approach using feature analysis. It brings up three new ideas: 1) to employ ranked position to emphasize the significance of sentence position, 2) to reshape word unit to achieve higher accuracy of keyword importance, and 3) to train a score function by the genetic algorithm for obtaining a suitable combination of feature weights. The second approach combines the ideas of latent semantic analysis and text relationship maps to interpret conceptual structures of a document. Both approaches are applied to Chinese text summarization. The two approaches were evaluated by using a data corpus composed of 100 articles about politics from New Taiwan Weekly, and when the compression ratio was 30%, average recalls of 52.0% and 45.6% were achieved respectively.
Comparison and combination of textual and visual features for interactive cross-language image retrieval
(2005)
Cheng, PC
;
Yeh, JY
;
Ke, HR
;
Chien, BC
;
Yang, WP
This paper concentrates on the user-centered search task at ImageCLEF 2004. In this work, we combine both textual and visual features for cross-language image retrieval, and propose two interactive retrieval systems T_ICLEF and VCT_ICLEF. The first one incorporates a relevance feedback mechanism based on textual information while the second one combines textual and image information to help users find a target image. The experimental results show that VCT_ICLEF had a better performance in almost all cases. Overall, it helped users find the topic image within a fewer iterations with a maximum of 2 iterations saved. Our user survey also reported that a combination of textual and visual information is helpful to indicate to the system what a user really wanted in mind.