Browsing by Author "Tseng, CM"

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Fractional steps scheme of finite analytic method for advection-diffusion equation
(2005-01-01)
Tsai, TL
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Tseng, CM
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Yang, JC
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土木工程學系
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防災與水環境研究中心
For simply finding local analytic solution, the time derivative in the traditional finite analytic (FA) method is generally replaced with a first-order finite difference approximation as a source term. However, this may induce excessive numerical diffusion, especially for advection-dominated transport problems. In this paper, a fractional steps scheme of the FA method without using the finite difference approximation to time derivative is proposed by applying the one-dimensional FA method whose local analytic solution is obtained from both spatial and time domains, together with the method of fractional steps. Four hypothetical examples, including two-dimensional and three-dimensional cases, are employed to investigate this newly proposed method as compared with the traditional FA method, the optimal unsteady FA method, and the alternating direction scheme of the hybrid FA method. The results show that the fractional steps scheme of the FA method can greatly diminish numerical diffusion and is superior to the other methods compared herein.
Is rigorous punishment effective? A case study of lifetime license revocation in Taiwan
(2006-03-01)
Chang, HL
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Woo, TH
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Tseng, CM
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
This study investigated the effectiveness of administrative lifetime driver's license revocation (ALLR) and its impact on offenders, based on a two-stage survey of 768 offenders. It was found that after ALLR had been imposed, 23.4% of these offenders were still driving almost the same as before, 59.8% drove significantly less frequently, and only 16.8% of the offenders gave up driving completely. The results of logistic regression models showed that offenders' compliance with ALLR was significantly correlated with their personal characteristics (age, income), penalty status (incarceration, duration of ALLR), and the need to drive for working, commuting and shopping. Elderly and low-income offenders were more likely to abide by the ALLR restriction. The application of the generalized estimating equations (GEE) model was used to identify the determinant factors affecting offenders' driving mileage, and to effectively estimate the driving mileage reduction as a result of the ALLR. It was found that ALLR is fairly effective in keeping offenders off the road, but that it may reduce their ability to make a living. resulting in the less fortunate becoming more helpless. (c) 2005 Elsevier Ltd. All rights reserved.
Photodissociation of nitrosobenzene and decomposition of phenyl radical
(2004-09-30)
Tseng, CM
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Choi, YM
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Huang, CL
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Ni, CK
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Lee, YT
Photodissociation of nitrosobenzene in a molecular beam has been studied by multimass ion imaging techniques. Photodissociation at 248 nm shows that there is only one dissociation channel, i.e., C6H5NO --> C6H5 + NO, regardless of the fact that the other channel, C6H5NO --> C6H4 + HNO, is energetically accessible in agreement with theoretically predicted results. Photodissociation at 193 nm also shows the same dissociation channel. However, about 10% of the C6H5 radicals produced at this wavelength further decomposed into benzyne and H atom, and the dissociation rates of phenyl radical as a function of internal energies were measured. The averaged photofragment translational energies released from the dissociation of nitrosobenzene at 193 and 248 nm are 10.2 and 6.9 kcal/mol, respectively, and fragment distributions are almost isotropic at both wavelengths. In addition, the thermal rate constant for dissociation of C6H5NO has been computed and compared with experimental data; the agreement between theory and experiment is excellent, confirming the most recently reported unusually high A-factor (> 10(17) s(-1)).