Browsing by Author "Hwang, SJ"

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A computerized quality function deployment approach for retail services
(1996-09-01)
Trappey, CV
;
Trappey, AJC
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Hwang, SJ
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管理科學系
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工業工程與管理學系
Product and service quality can only be effectively improved when the most important needs of customers are satisfied. Quality Function Deployment (QFD) is an approach used to guide R&D, manufacturing and management toward the development of products and services that satisfy the needs of consumers. The QFD operations are performed by way of a diagram called the House of Quality (HOQ). The HOQ contains information about the customers' needs (what), mechanisms to address these needs (how), and the criterion for deciding which ''what'' is the most important and which ''how'' provides the greatest customer satisfaction. A less familiar application of QFD is for the improvement of retail services. When QFD is applied to retail services, a computerized HOQ approach becomes integral to the process for providing continuous, iterative quality improvement. The objective of this research is to develop a formal QFD methodology for the retail industry and to build a computerized retail QFD system. The system provides a HOQ architecture for specifying and analyzing the customers' needs, deriving improvement strategies, and formalizing records of progress. Furthermore, two ranking methods that apply customer satisfaction theory are used to assist managers improve retail services. This system provides an integrated workbench for building retail HOQs and designing retail service strategies. Copyright (C) 1996 Elsevier Science Ltd
An efficient dynamic threshold scheme
(1996-07-01)
Hwang, SJ
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Chang, CC
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Yang, WP
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交大名義發表
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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 encryption/multisignature scheme with specified receiving groups
(1998-03-01)
Hwang, SJ
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Chen, CY
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Chang, CC
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資訊工程學系
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Department of Computer Science
In this paper, we propose a new multisignature scheme that allows all of the signers to specify the recipients. The encryption function is also integrated into our multisignature scheme, thus the new scheme can provide secrecy, authenticity, and integrity services. Moreover, the message expansion is also reduced. Comparing to the proposed multisignature scheme, the new scheme is the first one which allows the singers to specify the recipients.
Authenticated encryption schemes with message linkage
(1996-05-27)
Hwang, SJ
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Chang, CC
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Yang, WP
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資訊工程學系
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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.
Cryptanalysis of the Hwang-Shi proxy signature scheme
(2002-11-01)
Hwang, MS
;
Lee, CC
;
Hwang, SJ
;
資訊工程學系
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Department of Computer Science
Recently, Hwang and Shi proposed an efficient proxy signature scheme without using one-way hash functions. In their scheme, an original signer needn't send a proxy certificate to a proxy signer through secure channels. However, there are two public key substitution methods that can be used to attack their scheme. In this article, we show that their scheme is vulnerable to the public key substitution attacks.
Energy losses of charged particles moving parallel to the surface of an overlayer system
(2003-06-01)
Kwei, CM
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Hwang, SJ
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Li, YC
;
Tung, CJ
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電子工程學系及電子研究所
An energetic charged particle moving parallel to the surface of an overlayer system was studied. This system was composed of a thin film on the top of a semi-infinite substrate. Based on the dielectric response theory, the induced potentia I was formulated by solving the Poisson. equation and matching the boundary conditions. The stopping force was built-up using the energy-momentum conservation relations and the extended. Drude dielectric functions with spatial dispersion. Surface (vacuum-film) and interface (film-substrate) excitations were included in the formulations of the interaction between charged particles and the overlayer system. Results of the wake potential were presented for protons moving parallel to a vacuum-copper-silicon system. Dependences of the induced potential and the stopping force on film thickness, distance of the proton from surface, and proton velocity were investigated. (C) 2003 American Institute of Physics.
Some active attacks on fast server-aided secret computation protocols for modular exponentiation
(1996)
Hwang, SJ
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Chang, CC
;
Yang, WP
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資訊工程學系
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Department of Computer Science
Four server-aided secret computation protocols, Protocols 1, 2, 3, and 4, for modular exponentiation were proposed by Kawamura and Shimbo in 1993. By these protocols, the client can easily compute the modular exponentiation M(d) mod N with the help of a powerful server, where N is the product of two large primes. To enhance the security, the client was suggested to use a verification scheme and a slight modification on each proposed protocol. In this paper, we propose two new active attacks to break Protocols 3 and 4, respectively. Even if Protocols 3 and 4 have included the slight modification and verification, the untrusted server can still obtain the secret data d. The client cannot detect these attacks by the proposed verification. To adopt these new attacks, the difficulty of finding the value of the secret data d will be decreased drastically.