Browsing by Author "Peng, HY"

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A new closed-form solution for a radial two-layer drawdown equation for groundwater under constant-flux pumping in a finite-radius well
(2003-07-01)
Yeh, HD
;
Yang, SY
;
Peng, HY
;
環境工程研究所
;
Institute of Environmental Engineering
A mathematical model is presented for describing the groundwater flow in a radial two-layer confined aquifer system with a constant-flux pumping well that has a wellbore skin and finite well radius. The Laplace-domain solution for the model is first derived by the Laplace transforms; and the time-domain solution in terms of the aquifer drawdown is then obtained form the Laplace inversion using the Bromwich integral method. When neglecting the well radius, our Laplace-domain solution is shown to reduce to a Laplace-domain solution given by Butler [J. Hydrol. 101 (1988) 15]. A unified numerical approach including a root search approach, the Gaussian quadrature, and the Shanks method is employed for evaluating this time-domain solution. The evaluated results of the solution agree well with those of the Laplace-domain solution estimated by the modified Crump algorithm. This new solution can be used either to predict the spatial and temporal drawdown distributions in both the skin and formation zones or to investigate the effects of the skin type, skin thickness and well radius on the drawdown distribution. (C) 2003 Elsevier Science Ltd. All rights reserved.
An efficient hierarchical motion estimation on algorithm and its VLSI architecture
(2005)
Wu, BF
;
Peng, HY
;
Chen, CJ
;
Yu, TL
;
電控工程研究所
This manuscript addresses the design and implementation of an efficient hierarchical motion estimation algorithm, HMEA, using multiple motion vector candidates to increase the estimation quality. HMEA satisfies the high estimation performance and efficient VLSI implementation. The algorithm adopts multi-resolution frames to reduce the computation complexity, and the original frame is down sampled into one-fourth and one-sixteenth respectively. At the smallest resolution, the least two motion vector candidates are selected using full-search block matching algorithm with search range equals to 4. At the middle level, these two motion vector candidates are used as center points for local searches, and the search range is reduce to 2. Then, at the original resolution level, the final motion vector is obtained from local search around the single candidate from the middle level. This paper also describes an efficient VLSI architecture based on the HMEA. We implement this architecture with about 59K gates and 798 bytes of RAM for a search range of [-16.0, +15.5] by using a synthesizable VHDL.
An encrypted mobile embedded surveillance system
(2005)
Wu, BF
;
Peng, HY
;
Chen, CJ
;
Chan, YH
;
電控工程研究所
This manuscript addresses the design and implementation of an encrypted mobile embedded surveillance system, EMESS, including a wireless server and mobile devices. Not only the mobility of the hand-held devices, but also the surveillance system can work in a moving body, then, a real mobile surveillance system is provided. In the security applications of vehicles, EMESS also can provide the images of thieves and robbers to the vehicle owner. We complete the related works of EMESS and the corresponding application programs for wireless communication of hand-held devices.
Improved numerical evaluation of the radial groundwater flow equation
(2002-06-01)
Peng, HY
;
Yeh, HD
;
Yang, SY
;
環境工程研究所
;
Institute of Environmental Engineering
The closed-form solution for the hydraulic head, derived for the radial groundwater flow equation subject to the constant-head boundary condition at the wellbore, is in an integral form that covers an integration range from zero to infinity. The integral is difficult to evaluate due to the integrand not only consisting of the product and the square of the Bessel functions but also having a singularity at the origin. A unified numerical method is proposed to evaluate the solution with accuracy to five decimal places and for very wide ranges of dimensionless distances and times. This approach includes a singularity removal scheme, Newton's method, the Gaussian quadrature, and Shanks' method. It gives the dimensionless heads in tabular forms with better accuracy while comparing to those given by other approaches. A formula describing the flow rate across the wellbore, derived by the authors based on Darcy's law, is proved to equal those presented by Jaeger [Proc Royal Soc Edinburgh 61 (1942) 223] and Jacob and Lohman [Am Geo Union 33 (4) (1952) 559]. The same singularity removal scheme and the Gaussian quadrature are also employed to evaluate the wellbore flow rate. Computed values of dimensionless flow rate versus dimensionless time expressed in tabular forms are also correct to five decimal places. Both the tabular results of dimensionless hydraulic head and dimensionless flow rate may be useful in engineering applications. (C) 2002 Elsevier Science Ltd. All rights reserved.
University students' self-efficacy and their attitudes toward the Internet: the role of students' perceptions of the Internet
(2006-03-01)
Peng, HY
;
Tsai, CC
;
Wu, YT
;
教育研究所
;
師資培育中心
The attitudes and the self-efficacy that characterize learners relative to the Internet have been identified as important factors that affect learners' motivation, interests and performance in Internet-based learning environments. Meanwhile, learners' perceptions of the Internet may shape learners' attitudes and online behaviours. This study investigates university students' attitudes and self-efficacy towards the Internet, and explores the role that university students' perceptions of the Internet may play in their Internet attitudes and self-efficacy. The results indicate that university students demonstrate positive attitudes and adequate Internet self-efficacy and that these students are more inclined to view the Internet as a functional tool - a functional technology. Gender differences exist in university students' attitudes towards, and perceptions of, the Internet; that is, male students demonstrate Internet attitudes that are more positive than those of their female peers. Furthermore, students who perceive the Internet as a leisure tool ( e. g. as a tour or a toy) show more positive attitudes and communicative self-efficacy than students who use the Internet as a functional technology. Educators and researchers need to be aware of these differences and to take them into consideration in their instruction. Lastly, this study serves as a starting-point for research that more broadly explores learners' perceptions of the Internet.