Browsing by Author "Yen, CH"

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A low-complexity MP3 algorithm that uses a new rate control and a fast dequantization
(2005-05-01)
Yen, CH
;
Lin, YS
;
Wu, BF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This work presents a low-complexity MP3 algorithm over a fixed-point arithmetic. A new rate control is introduced for the MP3 encoding algorithm, rather than the rate control in ordinary MP3. The computational complexity of the rate control is reduced by taking the loop-independent components outside the loop and accelerating the nonuniform quantizer using a hybrid scheme. The hybrid scheme includes a lookup-table method for smaller numbers and a linear piecewise approximation for larger numbers. A precise method for predicting the quantizer parameter is developed to decrease the number of times the rate control is execute. hybrid scheme is also used in MP3 decoding algorithm to accelerate the dequantization. However, the approximation for larger numbers is two-tier. The first tier is a linear piecewise approximation that yields a rough value. The second tier uses the rough value as the initial value of the first -order Newton's method to obtain a more closely approximated value. The precise method for prediction has a statistically hit rate of 43%, and the new rate control consumes no more than 4.5 MIPS. The proposed dequantization consumes no more than 2.38 MIPS, and has an error-to-signal ratio of under 0.012%. The implementation Of the complexity-reduced MP3 algorithm over 16bit fixed-point arithmetic is subjectively tested to evaluate the quality of the complexity-reduced MP3 algorithm.
An error-correcting stream cipher design with state-hopping architecture
(2005-01-01)
Yen, CH
;
Wu, BF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A new architecture of stream cipher based oil state-hopping shift registers and a pseudorandom vector generator (PRVG) is introduced. The proposed Stream cipher merges secrecy coding and channel coding into one processing Step. It could be either a pure cryptosystem or a secrecy-channel coding by demand. Considered as cryptography, the PRVG generates pseudo random vectors which are treated as keystreams setting Lip the encryption scheme. This is different from the general concept in stream ciphers, state-hopping shift registers do not generate a pseudo random sequence but act as substitutions on plaintexts. Viewed as channel coding. the state-hopping shift registers play as the ones in convolution code and the PRVG generates a sequence of pseudorandom vector to determine the Trellis diagram. If the system acts as a pure cryptosystem. the decoding scheme is exactly the inverse of the encryption Scheme. When the error-correcting ability is chosen. a modified sequential decoding is proposed.
Characterizing the bit permutation networks obtained from the line digraphs of bit permutation networks
(2001-08-01)
Hwang, FK
;
Yen, CH
;
應用數學系
;
Department of Applied Mathematics
A bit permutation network is an s-stage interconnection network composed of d(n-1) d x d crossbar switches in each stage. This class of networks includes most of the multistage interconnection networks. Recently, Chang et al, [Networks 33 (1999), 261-267] showed that an s-stage d-nary bit permutation network N with d(n) inputs (outputs) can be characterized by an (s - 1)-vector (k(1),..., k(s-1)), where k(1) is an element of {1, ..., n - 1}. In this paper, we give a simple (but not trivial) formula to determine the characteristic vector of a new network G(N)(+), which is, approximately, the line digraph of N. We use this formula to obtain relations between some well-studied bit permutation networks. (C) 2001 John Wiley & Sons, Inc.
Design of a concurrent dual-band receiver front-end in 0.18um CMOS for WLANs IEEE 802.11a/b/g applications
(2004)
Jou, CF
;
Cheng, KH
;
Lien, WC
;
Wu, CH
;
Yen, CH
A fully monolithic dual-band concurrent receiver chip for IEEE 802.11 a, 802.11 b and 802.11 g applications is presented in a 0.18-mum CMOS 1P6M technology. A low IF architecture was chosen in order to achieve a low-cost and low-power solution with a high level of integration compared to direct conversion architecture. This mixer can operate as a sub-harmonic mixer and even as a traditional Gilbert mixer if LO ports connecting to each other to found two RF inputs and two LO inputs. For a 1.8V power supply, the overall power consumptions are 84.3 mW, with 3.5 dB and 6.3 dB overall receive-chain noise figure for 2.45 GHz and 5.25 GHz, respectively.
Intramolecular Diels-Alder reaction of furans with allenyl ethers followed by phenylthio and trialkylsilyl groups rearrangement
(1998-12-01)
Chuang, CT
;
Yen, CH
;
Wu, HJ
;
應用化學系
;
Department of Applied Chemistry
a new reaction involving an intramolecular Diels-Alder reaction of a furan diene with an allenyl ether dienophile followed by phenylthio group rearrangement was discovered. Treatment of the propargyl ethers 2a-c with t-BuOK in t-BuOH at 85 degrees C gave the phenylthio group rearrangement products 5a-c and 6a-c. A reaction involving an intramolecular Diels-Alder reaction of a furan diene with an allenyl ether dienophile followed by trialkylsilyl group rearrangement is also demonstrated.
Intramolecular Diels-Alder reaction of furans with allenyl ethers followed by phenylthio and trialkylsilyl groups rearrangement
(1998-12-01)
Chuang, CT
;
Yen, CH
;
Wu, HJ
;
應用化學系
;
Department of Applied Chemistry
a new reaction involving an intramolecular Diels-Alder reaction of a furan diene with an allenyl ether dienophile followed by phenylthio group rearrangement was discovered. Treatment of the propargyl ethers 2a-c with t-BuOK in t-BuOH at 85 degrees C gave the phenylthio group rearrangement products 5a-c and 6a-c. A reaction involving an intramolecular Diels-Alder reaction of a furan diene with an allenyl ether dienophile followed by trialkylsilyl group rearrangement is also demonstrated.
Intramolecular Diels-Alder reaction of furans with allenyl ethers followed by sulfur and silicon atom-containing group rearrangement
(1998-07-24)
Wu, HJ
;
Yen, CH
;
Chuang, CT
;
應用化學系
;
Department of Applied Chemistry
The intramolecular Diels-Alder reactions of a furandiene with an allenyl ether dienophile followed by the alkylthio, alkylsulfinyl, alkylsulfonyl, and trimethylsilyl group rearrangements are reported. Refluxing the propargyl ether 3 with t-BuOK in t-BuOH at 85 degrees C gave the 1,4-rearrangement product 4 exclusively. The alkylthio group 1,4-rearrangement may proceed intramolecularly via the tight; ion pairs. Refluxing the 5-(alkylsulfinyl)-2-furfuryl propargyl ethers 9a-e and the 5-(alkylsulfonyl)-2-furfuryl propargyl ethers 19a-e under the same reaction conditions gave the alkylsulfinyl group and the alkylsulfonyl group 1,2-rearrangement products 10a-e and 20a-e, respectively. No detectable amount of the corresponding 1,4-rearrangement products 11a-e and 21a-e was obtained. In the cases of 9b and 19b, which possess two furfurylic hydrogen atoms, no detectable amount of the furan ring-transfer reaction products was obtained. Refluxing the 5-(trimethylsilyl)-2-furfuryl propargyl ethers 25a-d with t-BuOK in t-BuOH at 85 degrees C for 10 h gave the trimethylsilyl group 1,2-rearrangement products 26a-d and Brook rearrangement products 27a-d. The reaction mechanisms for these novel intramolecular Diels-Alder reactions are discussed. In the case of 37, which possesses two furfurylic hydrogen atoms, compound 38 was obtained via an intramolecular Diels-Alder reaction followed by the furan ring-transfer reaction and Brook rearrangement.
Intramolecular Diels-Alder reaction of furans with allenyl ethers followed by trimethylsilyl group 1,2-rearrangement and Brook rearrangement
(1996-10-07)
Wu, HJ
;
Yen, CH
;
Chuang, CT
;
應用化學系
;
Department of Applied Chemistry
The base-catalyzed intramolecular Diels-Alder reactions of 5-trimethylsilyl-2-furfuryl propargyl ethers la-lf gave compounds 2a-2f and 3a-3f in 70-90% yields respectively, a novel reaction involving an intramolecular Diels-Alder reaction followed by a trimethylsilyl group 1,2-rearrangement and Brook rearrangement. Copyright (C) 1996 Elsevier Science Ltd
Intramolecular Diels-Alder reaction of furans with allenyl ethers followed by trimethylsilyl group 1,2-rearrangement and Brook rearrangement
(1996-10-07)
Wu, HJ
;
Yen, CH
;
Chuang, CT
;
交大名義發表
;
應用化學系
The base-catalyzed intramolecular Diels-Alder reactions of 5-trimethylsilyl-2-furfuryl propargyl ethers la-lf gave compounds 2a-2f and 3a-3f in 70-90% yields respectively, a novel reaction involving an intramolecular Diels-Alder reaction followed by a trimethylsilyl group 1,2-rearrangement and Brook rearrangement. Copyright (C) 1996 Elsevier Science Ltd
Simple error detection methods for hardware implementation of advanced encryption standard
(2006-06-01)
Yen, CH
;
Wu, BF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In order to prevent the Advanced Encryption Standard (AES) from suffering from differential fault attacks, the technique of error detection can be adopted to detect the errors during encryption or decryption and then to provide the information for taking further action, such as interrupting the AES process or redoing the process. Because errors occur within a function, it is not easy to predict the output. Therefore, general error control codes are not suited for AES operations. In this work, several error-detection schemes have been proposed. These schemes are based on the (n + 1, n) cyclic redundancy check (CRC) over GF(2(8)), where n n is an element of {4, 8, 16,}. Because of the good algebraic properties of AES, specifically the Mixcolumns operation, these error detection schemes are suitable for AES and efficient for the hardware implementation; they may be designed using round-level, operation-level, or algorithm-level detection. The proposed schemes have high fault coverage. In addition, the schemes proposed are scalable and symmetrical. The scalability makes these schemes suitable for an AES circuit implemented in 8-bit, 32-bit, or 128-bit architecture. Symmetry also benefits the implementation of the proposed schemes to achieve that the encryption process and the decryption process can share the same error detection hardware. These schemes are also suitable for encryption-only or decryption-only cases. Error detection for the key schedule in AES is also proposed and is based on the derived results in the data procedure of AES.
Synthesis of dioxa-cages as a new probe for the stereochemistry of the bisadducts of p-quinone with cyclopentadiene and cyclohexadiene
(1998-12-01)
Yen, CH
;
Tsai, SH
;
Wu, HJ
;
應用化學系
;
Department of Applied Chemistry
The synthesis of dioxa-cages via iodine-induced cyclization reaction can be used as a new method for the determination of the stereochemistry of the bisadducts of p-quinone with cyclopentadiene and cyclohexadiene. The bisadducts 2 and 8 were converted into the dioxa-cages 13a and 13b via a three-step sequence, respectively. The stereochemistry of 13a and 13b was determined on the basis of NOE experiments.
Tessellating polyominos in the plane
(2006-06-28)
Chen, MY
;
Hwang, FK
;
Yen, CH
;
應用數學系
;
Department of Applied Mathematics
Let the R-2 space be divided into unit squares where a polyomino is a finite, connected set of unit squares. In this paper, we give a necessary and sufficient condition on tessellating polyominos by observing an unexpected relation between such tessellations and systems of arithmetic progressions. (c) 2006 Elsevier B.V. All rights reserved.