Browsing by Issue Date, starting with "1998-02-19"

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Effects of N2O-annealed sacrificial oxide on the short-channel effects of nMOSFETs
(1998-02-19)
Jong, FC
;
Huang, TY
;
Chao, TS
;
Lin, HC
;
Wang, MF
The authors report the effects of N2O-annealed sacrificial oxide on nMOSFETs. It is demonstrated that by adding an N2O-annealing step to the sacrificial. oxide which was stripped off before growing the final gate oxide, the reverse short-channel effects (RSCE) can still be effectively suppressed.
Effects of 3 '-phosphoadenosine 5 '-phosphate on the activity and folding of phenol sulfotransferase
(1998-02-20)
Yang, YS
;
Tsai, SW
;
Lin, ES
;
生物科技學系
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Department of Biological Science and Technology
Known spectroscopic and kinetic data are used to formulate pathways of the physiological and transfer reactions and the substrate inhibition of phenol sulfotransferase. Kinetic mechanisms indicate that release of PAP from enzyme complex is required for the physiological reaction but not for the transfer reaction. The pathways explain rate difference between the physiological and transfer reactions since the release of PAP is the rate-limiting step of the former reaction. Two enzyme species of phenol sulfotransferase which distinguish the physiological and transfer reaction were found to involve the binding of PAP. Differences between two forms of phenol sulfotransferase, alpha and beta, indicate that they assemble through different folding process. It is demonstrated that only alpha enzyme renatures in the presence of PAP and beta enzyme renatures only ir. the absence of PAP in vitro. In the over-expressed system, formation of alpha and beta phenol sulfotransferase is also dependent on the availability of PAP in Escherichia coli. It is concluded that folding of phenol sulfotransferase is assisted by PAP to form alpha enzyme. In the absence of PAT, beta form of phenol sulfotransferase is produced. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.
Quantum dynamics of a diatomic molecule under chirped laser pulses
(1998-02-28)
Lin, JT
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Lai, TL
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Chuu, DS
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Jiang, TF
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電子物理學系
The photodissociation probability of a diatomic molecule is usually very small even under a strong field due to its anharmonicity. However, the progress in laser technology provides a chirped laser pulse to lower the threshold of the dissociation intensity. We investigate the quantum dynamics of a diatomic molecule under such a kind of pulse. It is found that there is a significant dissociation probability at moderate intensity for a diatomic molecule under a chirped pulse. The quantum dissociation probability is found to be suppressed with respect to the classical one for intensities above the dissociation threshold. Therefore the chirped pulse can efficiently dissociate a diatomic molecule.
Solving facility-layout optimization problems with clustering constraints
(1998-03-01)
Li, HL
;
Hsieh, MC
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資訊管理與財務金融系註：原資管所+財金所
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Department of Information Management and Finance
Most facility-layout problems are at present solved by heuristic methods, which are not suitable for treating layout problems if some facilities need to be placed together. In this paper we add the constraints of clustering facilities and thus propose an optimization model for facility-layout problems. The advantages of introducing clustering constraints are: first, they fit the more practical rationale of facility layouts; second, they can help improve the computational efficiency owing to the reduction in nonoverlapping constraints among the facilities.
Bound water content and water binding strength on sludge flocs
(1998-03-01)
Wu, CC
;
Huang, CP
;
Lee, DJ
;
環境工程研究所
;
Institute of Environmental Engineering
On the basis of the thermodynamic hypothesis and using the thermodynamic approach, a binding strength was calculated to define the physical meaning of bound water content of sludge as measured by dilatometer. The sludge samples considered in this study included kaolin, alum and biological sludge. The binding strength of bound water at -20 degrees C was calculated as 24.5 kJ/kg, which is close to that of the normal physico-adsorption process. Most of the frozen moisture in st dilatometric measurement should be interstitial water or vicinal water. Results also indicated that moisture with a lower binding strength easily became free water. The release of interstitial water from sludge flocs would cause less bound water. When solid concentration is higher, the expelling strength induced by the compacting action of sludge flocs is increased over the binding strength, thereby forcing out the interstitial water. Lower bound water contents are attained. Accurate measurement of bubble volumes with the calculated stem on the top of the dilatometer could improve the precision of expansion coefficient and bound water content measurement. (C) 1998 Elsevier Science Ltd. All rights reserved.
Improvements on Sloan's algorithm for constructing Delaunay triangulations
(1998-03-01)
Huang, CW
;
Shih, TY
;
土木工程學系
;
Department of Civil Engineering
Similarity retrieval by 2D C-trees matching in image databases
(1998-03-01)
Hsu, FJ
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Lee, SY
;
Lin, BS
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
The image retrieval based on spatial content is an attracting task in many image database applications. The 2D strings provide a natural way of constructing spatial indexing for images and support effective picture query. Nevertheless, the 2D string is deficient in describing the spatial knowledge of nonzero sized objects with overlapping. In this paper, we use an ordered labeled tree, a 2D C-tree, to be the spatial representation for images and propose the tree-matching algorithm for similarity retrieval. The distance between 2D C-trees is used to measure the similarity of images. The proposed tree comparison algorithm is also modified to compute the partial tree distance for subpicture query. Experimental results for verifying the effectiveness of similarity retrieval by 2D C-trees matching are presented. (C) 1998 Academic Press.
GMNF-DVMRP: An enhanced version of distance vector multicast routing protocol
(1998-03-01)
Lai, YC
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Lin, YD
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Yu, WC
;
資訊工程學系
;
Department of Computer Science
In this paper we propose an enhancement to the Distance Vector Multicast Routing Protocol (DVMRP), called 'Group Membership Near First DVMRP' (GMNF-DVMRP), to decrease the network cost (NC) of the multicast tree formed by DVMRP. A simulation is implemented to compare our enhanced version and the original DVMRP. We find that our method saves about 5%-7% of NC of the multicast tree formed by DVMRP. (C) 1998 John Wiley & Sons, Ltd.
High-performance capillary electrophoretic analysis of synthetic food colorants
(1998-03-01)
Kuo, KL
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Huang, HY
;
Hsieh, YZ
;
應用化學系
;
Department of Applied Chemistry
A high-performance capillary electrophoresis method with diode-array detection has been developed for analysis of synthetic food colorants. The influence of buffer composition on the separation of the food colorants was examined, as were the effects of alpha-, beta- and gamma-cyclodextrins on analyte migration behavior. Eight food colorants were completely separated within 10 min using pH 9.5 borax - NaOH buffer containing 5 mM beta-cyclodextrin. Experimental results indicate that the relative standard deviations of analyte migration times were < 0.88% under the optimized separation condition. Correlation coefficients of the linear calibration plots of the analytes exceeded 0.998. The method was suitable for determination of the quantities of synthetic food colorants in ice cream bars and fruit soda drinks.
Computerized tooth profile generation and undercut analysis of noncircular gears manufactured with shaper cutters
(1998-03-01)
Chang, SL
;
Tsay, CB
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機械工程學系
;
Department of Mechanical Engineering
Pitch curves of a conjugate noncircular gear pair are derived based on kinematic considerations. A method for considering the inverse mechanism relationship and the equation of meshing, is proposed here to derive a complete mathematical model of noncircular gears manufactured with involute-shaped shaper-cutters. The proposed method is similar to the contact line method and the envelope method but is easier to apply to the determination of tooth profiles. A computer program is developed for generation the tooth profile with backlashes. Undercutting analysis is also investigated by considering the relative velocity and equation of meshing. Finally modified elliptical gears are presented to illustrate the tooth profile generation when the proposed mathematical model is applied and to investigate the phenomenon of tooth undercutting.
New imidazoles as probes of the active site topology and potent inhibitors of beta-glucosidase
(1998-03-01)
Li, YK
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Hsu, HS
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Chang, LF
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Chen, G
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應用化學系
Series of 4-arylimidazoles, omega-N-acylhistamines and 4-(omega-phenylalkyl) imidazoles were synthesized in order to probe the active site topology of sweet almond beta-glucosidase. These imidazole derivatives were shown to be very powerful competitive inhibitors. Among the 20 tested compounds, omega-N-benzoylhistamine and 4-(3'-phenylpropyl)imidazole are the most potent inhibitors of the enzyme, with pH-independent K-i values of 0.06 and 0.07 mu M, respectively, The inhibition of 4-(omega-phenylalkyl)imidazoles exhibited an interesting trend as to K-i values: 4-phenylimidazole (6.6 mu M)>4-benzylimidazole (1.4 mu M)>4-(2'-phenylethyl)imidazole (0.82 mu M)>4-(3'-phenylpropyl)imidazole (0.07 mu M)<4-(4'-phenylbutyl)imidazole (0.13 mu M)<4-(5'-phenylpentyl)imidazole (0.3 mu M), This revealed that the imidazole and aryl binding sites (which result from favorable interactions within the corresponding glycone and aglycone binding subsites) are separated by the optimal distance equivalent to the length of a -CH2-CH2-CH2-group, Substitutions of the phenyl moieties of 4-phenylimidazole and 4-benzoylhistamine result in weaker inhibition, These classes of imidazoles are particularly powerful inhibitors of sweet almond beta-glucosidase.
Robot control optimization using reinforcement learning
(1998-03-01)
Song, KT
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Sun, WY
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電控工程研究所
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Institute of Electrical and Control Engineering
Conventional robot control schemes are basically model-based methods. However, exact modeling of robot dynamics poses considerable problems and faces various uncertainties in task execution. This paper proposes a reinforcement learning control approach for overcoming such drawbacks. An artificial neural network (ANN) serves as the learning structure, and an applied stochastic real-valued (SRV) unit as the learning method. Initially, force tracking control of a two-link robot arm is simulated to verify the control design. The simulation results confirm that even without information related to the robot dynamic model and environment states, operation rules for simultaneous controlling force and velocity are achievable by repetitive exploration. Hitherto, however, an acceptable performance has demanded many learning iterations and the learning speed proved too slow for practical applications. The approach herein, therefore, improves the tracking performance by combining a conventional controller with a reinforcement learning strategy. Experimental results demonstrate improved trajectory tracking performance of a two-link direct-drive robot manipulator using the proposed method.
Broadcasting secrets in communication networks
(1998-03-01)
Chang, CC
;
Wu, TC
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Yeh, YS
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資訊科學與工程研究所
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Institute of Computer Science and Engineering
One property of a broadcast channel is that a single message broadcasted from an originator may be received simultaneously by several recipients in communication links. Based on the Chinese remainder theorem (CRT), we propose a new secure broadcasting scheme to distribute different secrets in one single broadcasting transaction such that each of the secrets is dedicated to different authorized recipients. On receiving the ciphertext broadcasted by the originator, only authorized recipients can obtain and authenticate their dedicated secrets individually, while no secret is revealed to unauthorized recipients. In a single broadcasting transaction, each authorized recipient cannot know who are the other intended recipients for this transaction. Furthermore, the processes for decryption and authentication of the dedicated secret are performed through simple arithmetic computation, i.e., modular operations, hence it is suitable for the applications that the recipient has less computing power. We also show that the proposed scheme can withstand the attack on replaying a previously intercepted broadcasting message.
A novel fabrication technique of T-shaped gates using an EGMEA and PMIPK multilayer resist system and a single-step electron-beam exposure
(1998-03-01)
Lai, YL
;
Lai, YK
;
Chang, CY
;
Chang, EY
;
材料科學與工程學系
A novel fabrication process of submicron T-shaped gates using an EGMEA and PMIPK multi-layer resist system and e-beam lithography has been developed. Due to the different sensitivities of the EGMEA and PMIPK resists, narrow/wide/narrow resist opening was obtained. The status of the electron scattering and the incident primary electron beams statistically construct the absorbed energy density distribution contours. The absorbed energy density distribution contours in association with the sensitivity feature of the resists and the appropriate development conditions determine the final resist profile. Only a single exposure step and a single development step are required. The simplified fabrication process of T-shaped gates significantly reduces not only the process time but also the production costs. The simple submicron T-shaped gate fabrication process studied provides a suitable technique for the mass manufacture of the advanced InP-based and GaAs-based microwave devices and circuits.
Multi-objective machine-component grouping in cellular manufacturing: a genetic algorithm
(1998-03-01)
Hsu, CM
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Su, CT
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工業工程與管理學系
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Department of Industrial Engineering and Management
The cellular manufacturing system (CMS) is an important group technology (GT) application. The first step of CMS design is cell formation, generally known as machine-cell formation (MCF) or machine-component grouping (MCG). A genetic algorithm (CA) is a robust adaptive optimization method based on principles of natural evolution and is appropriate for the MCG problem, which is an NP complete complex problem. In this study, we propose a GA-based procedure to solve the MCG problem. More specifically, this study aims to minimize (1) total cost, which includes intercell and intracell part transportation costs and machines investment cots; (2) intracell machine loading imbalance; and (3) intercell machine loading imbalance under many realistic considerations. An illustrative example and comparisons demonstrate the effectiveness of this procedure. The proposed procedure is extremely adaptive, flexible, efficient and can be used to solve real MCG problems in factories by providing robust manufacturing cell formation in a short execution time.
Optimal MISO repetitive control system design using mixed time and frequency domain criteria
(1998-03-01)
Hu, JS
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Yu, SH
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Huang, SC
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電控工程研究所
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Institute of Electrical and Control Engineering
This paper presents an optimal repetitive controller design approach when both frequency and time domains criteria are considered. These criteria include limited control force, convergence rate, and robustness. In particular, the design formulation is based on MISO (multiple-input-single-output) plants which aim at solving nodal point problems encountered in flexible dynamic systems. Nodal points represent physical constraints for feedback control, especially when their frequencies are within the control bandwidth. If multiple control paths with distinct nodal frequencies are available, the proposed method is able to design controllers to compensate the effect and reach certain design objectives. The ellipsoid algorithm is used to calculate controllers' parameters. Experiments were conducted to demonstrate the proposed method.
Linewidth-deduction method for nonlinear optical spectroscopy with transform-limited light pulses
(1998-03-01)
Yang, PK
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Huang, JY
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光電工程學系
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Department of Photonics
We have developed a Fourier-deconvolution-based linewidth-deduction method for nonlinear optical spectroscopy with transform-limited light pulses. The phase-retrieval problem involved in this method was solved with a phase-retrieval procedure based on the maximum-entropy model. Our proposed method can also help one to surpass the resolution limit set by the uncertainty principle when the amplitude line-shape function of the laser source can be fully predetermined. (C) 1998 Optical Society of America [S0740-3224(98)00303-8].
D-stability analysis for discrete uncertain time-delay systems
(1998-03-01)
Hsiao, FH
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Hwang, JD
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Pan, SP
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電控工程研究所
;
Institute of Electrical and Control Engineering
Two cases of the robust D-stability criterion are derived for discrete uncertain systems with multiple time delays. One is a direct test and the other is a boundary test. These cases provide the sufficient conditions under which all solutions of the characteristic equation remain inside the specific disk D(alpha, r) in the presence of parametric uncertainties.
Role of perovskite PMN in phase formation and electrical properties of high dielectric Pb[(Mg-x, Zn1-x)(1/3)Nb-2/3]O-3 ceramics
(1998-03-01)
Chen, SY
;
Wang, CM
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Cheng, SY
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The structural evolution of perovskite phase Pb[(MgxZn1-x)(1/3)Nb-2/3]O-3 (abbreviated to PZMN) was found to be highly dependent on its precursors' strong tendency of forming pyrochlore phase in the mixture of raw materials. Three major pyrochlore compositions, Pb2Nb2O7, Pb3Nb2O8 and Pb3Nb4O13, were characterized and analyzed to understand their roles in the formation of the perovskite PZMN phase. Based on phase structure evolution, a preparation method for forming high dielectric constant PZMN ceramics without using common stabilizers such as SrTiO3 was proposed. By using pre-synthesized perovskite PMN, a Zn-rich PZMN composition with an almost 100% perovskite content and a maximum dielectric constant of 22 000 at 1 kHz is obtained. The formation mechanism of PZMN perovskite phase was also reported in this research. The pre-synthesized perovskite PMN acts as stabilizer and nuclei to initiate PZMN perovskite formation through the reaction in the PMN/ZnO interface. A ternary phase diagram of PMN-PZN-SrTiO3 was further constructed to investigate the perovskite development and its related electrical properties. (C) 1998 Elsevier Science S.A.
Force control of a single-link flexible arm using sliding-mode theory
(1998-03-01)
Chang, JL
;
Chen, YP
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Motivated by the relation between a force acting on a flexible arm and the resultant bending deflection, this paper presents a force control technique simply via position control. The dynamic equations of a flexible arm with tip position placed on a fu;ed horizontal plane are modeled by an approach similar to the finite element method. Based on this model, the constraint force on the horizontal plane can be directly estimated from the motor's angle and the bending deflection, and thus the use of force sensor is no longer needed. The controller structure consists of two nested feedback loops in which the inner loop is designed for the motor's angle by a PD control algorithm and the outer loop deals with the constraint force by sliding-mode control. Experimental results are included to demonstrate the success of the developed controller.