Browsing by Issue Date, starting with "1996-05-20"

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Algorithmic aspects of the generalized clique-transversal problem on chordal graphs
(1996-05-20)
Chang, MS
;
Chen, YH
;
Chang, GJ
;
Yan, JH
;
應用數學系
Suppose G=(V,E) is a graph in which each maximal clique C-i is associated with an integer r(i), where 0 less than or equal to r(i) less than or equal to\C-i\. The generalized clique transversal problem is to determine the minimum cardinality of a subset D of V such that \D boolean AND C-i\greater than or equal to r(i) for every maximal clique C-i of G. The problem includes the clique-transversal problem, the i,1 clique-cover problem, and for perfect graphs, the maximum q-colorable subgraph problems as special cases. This paper gives complexity results for the problem on subclasses of chordal graphs, e.g., strongly chordal graphs, k-trees, split graphs, and undirected path graphs.
Algorithmic aspects of the generalized clique-transversal problem on chordal graphs
(1996-05-20)
Chang, MS
;
Chen, YH
;
Chang, GJ
;
Yan, JH
;
應用數學系
Suppose G=(V,E) is a graph in which each maximal clique C-i is associated with an integer r(i), where 0 less than or equal to r(i) less than or equal toC-i. The generalized clique transversal problem is to determine the minimum cardinality of a subset D of V such that D boolean AND C-igreater than or equal to r(i) for every maximal clique C-i of G. The problem includes the clique-transversal problem, the i,1 clique-cover problem, and for perfect graphs, the maximum q-colorable subgraph problems as special cases. This paper gives complexity results for the problem on subclasses of chordal graphs, e.g., strongly chordal graphs, k-trees, split graphs, and undirected path graphs.
Synthesis of (-)-furodysinin from (+)-limonene
(1996-05-21)
Ho, TL
;
Chein, RJ
;
應用數學系
;
Department of Applied Mathematics
Furodysinin is synthesised by elaboration of (1R, 2R)-(+)-limonene oxide; key reactions include a tandem Claisen rearrangement-ene reaction and trapping of a conjugate adduct of an enone providing a bicyclic precursor of the sesquiterpene.
Synthesis of (-)-furodysinin from (+)-limonene
(1996-05-21)
Ho, TL
;
Chein, RJ
;
交大名義發表
;
應用數學系
;
National Chiao Tung University
Furodysinin is synthesised by elaboration of (1R, 2R)-(+)-limonene oxide; key reactions include a tandem Claisen rearrangement-ene reaction and trapping of a conjugate adduct of an enone providing a bicyclic precursor of the sesquiterpene.
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.
青蛙案件物語
(1996-05-31)
管管
青蛙案件物語
(1996-05-31)
管管
First exclusive regioselective fragmentation of primary ozonides controlled by remote carbonyl groups and a new method for determining the regiochemistry of carbonyl oxide formation
(1996-05-31)
Wu, HJ
;
Lin, CC
;
交大名義發表
;
應用化學系
;
National Chiao Tung University
The first exclusive regioselective fragmentation of primary ozonides controlled by remote carbonyl groups on ozonolysis of norbornene derivatives and reaction of final ozonides with triethylamine as a new probe for determining the regiochemistry of carbonyl oxide formation from primary ozonide fragmentation are reported. Ozonolysis of the endo adducts 3a-d and the deuterated compounds 8a and 8b in CDCl3 at -78 degrees C gave the final ozonides 4a-d, 9a, and 9b as the sole products (>95%), respectively. No detectable amount of the isomeric final ozonides 5, 10, ii, and 12 was obtained. A mechanism is proposed to account for the exclusive regioselective fragmentation of the primary ozonides. Ozonolysis of 3a-d, Ba, and 8b in CH2Cl2 at -78 degrees C followed by treatment with triethylamine exclusively gave the convex tetraquinane oxa cage compounds 16a-d, 19a, and 19b in 85-90% yields, respectively. No detectable amount of the other regioisomers 17a-d, 20a, and 20b was obtained. Ozonolysis of 3a-d, 8a, and 8b in CH2Cl2 at -78 degrees C followed by reduction with dimethyl sulfide gave the tetraacetal tetraoxa cage compounds 21a-d, 23a, and 23b in 85% yields, respectively. The difference in function between triethylamine and dimethyl sulfide in reaction with final ozonide is demonstrated. Ozonolysis of the endo adducts 24a and 24b in CDCl3 at -78 degrees C exclusively gave the final ozonides 27a and 27b, respectively, The order of the preference of various remote carbonyl groups to control the fragmentation of the primary ozonides formed by ozonolysis of norbornene derivatives is investigated. Ozonolysis of the endo esters 32a-c in CH2Cl2 at -78 degrees C followed by reduction with dimethyl sulfide gave the new tetraacetal oxa cages 35a-c, with an alkoxyl group directly on the skeleton, and the novel triacetal oxa cages 36b and 36c, respectively. The structures of triacetal oxa cages are proven for the first time by X-ray analysis of the crystalline compound 36c.
青蛙案件物語
(1996-05-31)
管管
青蛙案件物語
(1996-05-31)
管管
A new extraction algorithm for the metallurgical channel length of conventional and LDD MOSFET's
(1996-06-01)
Jean, YS
;
Wu, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A new extraction algorithm for the metallurgical channel length of conventional and LDD MOSFET's is presented, which is based on the well-known resistance method with performing a special technique to eliminate the uncertainty of the channel length as well as to reduce the influence of the parasitic source/drain resistance on threshold-voltage determination. In particular, the metallurgical channel length is determined from a wide range of gate-voltage-dependent effective channel length at an adequate gate overdrive, The 2-D numerical analysis clearly show that the adequate gate overdrive is strongly dependent on the dopant concentration in the source/drain region, Therefore, an analytic equation is derived to determine the adequate gale overdrive for various source/drain and channel doping, It shows that higher and lower gate overdrives are needed to accurately determine the metallurgical channel length of conventional and LDD MOSFET devices, respectively. It is the first time that we can give a Correct gate overdrive to extract L(met) not only for conventional devices but also for LDD MOS devices. Besides, the parasitic source/drain resistance call also he extracted using our new extraction algorithm.
Back-gate forward bias method for low-voltage CMOS digital circuits
(1996-06-01)
Chen, MJ
;
Ho, JS
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Huang, TH
;
Yang, CH
;
Jou, YN
The back-gate forward bias method suitable for present standard hulk CMOS processes has been promoted for low-voltage digital circuit application, A CMOS inverter employing the method has experimentally exhibited the ability of electrically adjusting the transition region of the de voltage transfer characteristics. Transient measurement has further shown that the inverter with a back-gate forward bias of 0.4 V can operate at low supply voltages down to 0.6 V without significant loss in switching speed, Guidelines for ensuring proper implementation of tile method in a bulk CMOS process has been set up against latch-up, parasitic bipolar, impact ionization, and stand-by current, Following these guidelines, a cost-effective low-power, low-voltage, high-density mixed-mode CMOS analog/digital integrated circuits chip with both reasonable speed and improved precision has been projected for the first time.
Two-color above-threshold ionization of atoms
(1996-06-01)
Han, CS
;
電子物理學系
;
Department of Electrophysics
A nonperturbative method is used to study the two-color multiphoton ionization of atoms by solving the Schrodinger equation in momentum space, which facilitates the extraction of the rapidly varying part of the wave function. Our method generalizes the problem for cases where an arbitrary number of ionization photons are absorbed, and also takes into account the threshold shifts due to both the high- and low-frequency fields. The photoelectron energy spectra of the hydrogen atoms are calculated and the dependence on the laser field strengths and frequencies is discussed.
A speech recognition method based on the sequential multi-layer perceptrons
(1996-06-01)
Chen, WY
;
Chen, SH
;
Lin, CJ
;
交大名義發表
;
National Chiao Tung University
A novel multi-layer perceptrons (MLP)-based speech recognition method is proposed in this study. In this method, the dynamic time warping capability of hidden Markov models (HMM) is directly combined with the discriminant based learning of MLP for the sake of employing a sequence of MLPs (SMLP) as a word recognizer. Each MLP is regarded as a state recognizer to distinguish an acoustic event. Next, the word recognizer is formed by serially cascading all state recognizers. Advantages of both HMM and MLP methods are attained in this system through training the SMLP with an algorithm which combines a dynamic programming (DP) procedure with a generalized probabilistic descent (GPD) algorithm. Additionally, two sub-syllable SMLP-based schemes are studied through application of this method toward the recognition of isolated Mandarin digits. Simulation results confirm that the performance of the methods is comparable to a well modeled continuous Gaussian mixture density HMM trained with the minimum error criterion. Not only does the SMLP require less trainable parameters than the HMM system, but the former is more convenient for analysing internal features. With the aid of internal feature selection, discarding the least useful parameters of SMLP without affecting its performance is relatively easy. Copyright (C) 1996 Elsevier Science Ltd
Coupling-efficiency analysis and control of dual antiresonant reflecting optical waveguides
(1996-06-01)
Chen, YH
;
Huang, YT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We have developed the necessary theory to analyze the coupling efficiency of dual ARROW waveguide. Based on the theory, we have found that the coupling efficiency of dual ARROW waveguides can be flexibly controlled from a 100% value to zero by simply varying the outermost cladding thickness. BPM simulations also give same results and verify the theory. The theory and simulation results can be efficiently applied to designing an ARROW power divider with any specified power ratio.
Stereoselectivity of the Diels-Alder reaction of (E)gamma-Oxo-alpha,beta-unsaturated thioesters with cyclopentadiene
(1996-06-01)
Tsai, SH
;
Chung, WS
;
Wu, HJ
;
應用化學系
;
Department of Applied Chemistry
The stereoselectivity of the Diels-Alder reaction of (E)-gamma-oxo-alpha,beta-unsaturated thioesters 3a-3d with cyclopentadiene is greatly enhanced in the presence of Lewis acids favoring the endo acyl isomers 4a-4d. In the absence of Lewis acid, Diels-Alder reaction of 3a-3d with cyclopentadiene at 25 degrees C gave two adducts 4a-4d and 5a-5d in a ratio of 1:1 respectively. In the presence of Lewis acids, Diels-Alder reaction of 3a-3d with cyclopentadiene gave 4a-4d and 5a-5d in ratios of 75 similar to 94:25 similar to 6 respectively. The stereoelectivity was enhanced to ratios of 95 similar to 98:5 similar to 2 with lowering the reaction temperature. The stereochemistry of the cycloadducts 4 and 5 was confirmed by iodocyclization. Reaction of the endo-thioester 5c with I-2 in aqueous THF at 0 degrees C gave the novel methylthio group rearranged product 6c in 80% yield, the first example of iodolactonization of endo-thioesters. Reaction of the endo-acyl isomer 4b with I-2 under the same reaction conditions gave an isomeric mixture of 7b and 8b in 1:2 ratio. The stereochemistry of the thioester group in 8b was proved by X-ray single-crystal analysis. The solvent effect on the endo selectivity of (Z)-gamma-oxo-alpha,beta-unsaturated thioester 2b was also examined.
PA CS: Personal access communications system - A tutorial
(1996-06-01)
Noerperl, AR
;
Lin, YB
;
Sherry, H
;
資訊工程學系
;
Department of Computer Science
The Personal Access Communications System (PACS) is an American National Standards Institute common air interface standard developed for the 1.9 GHz PCS band in the United Stales. PACS uses frequency division duplexing technology and is optimized to support low-mobility pedestrian outdoor usage and wireless local loop applications in a medium-range environment. PACS-Unlicensed B (PACS-UB) is a version of PACS using time division duplexing. PACS-UB has been optimized for private, indoor wireless PBX applications and cordless telephony. Both modes of operation are supported using the same portable hardware and the same signaling protocol.
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.
The effect of lead impurity on the DC-etching behaviour of aluminum foil for electrolytic capacitor usage
(1996-06-01)
Lin, W
;
Tu, GC
;
Lin, CF
;
Peng, YM
;
材料科學與工程學系
The effects of lead impurity on the etched morphology of high purity aluminum foils for electrolytic capacitor applications were investigated in this work. The lead impurity was either present in as-received aluminum foils or deposited purposely on the foil surface through an immersion-reduction reaction. The amount and distribution of deposited lead varies with the lead content in as-received foil. The as-received foil with higher lead content gave a higher concentration and a more uniform distribution of deposited lead. Uniformly distributed vertical tunnel etchings were obtained when high lead foil, formed by immersion as-received high lead foil in Pb(NO3)(2) solution, was subject to DC-etching. For the as-received lower lead foils, the deposited lead was concentrated in rolling lines which resulted in surface etching along rolling lines. Both the surfacial and cross-sectional etching morphologies are presented in this study, together with the etching mechanism discussed. Copyright (C) 1996 Elsevier Science Ltd.