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Search Results: 1 - 10 of 35502 matches for " Yi Pan "
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Optimal degeneracy for the signal-recycling cavity in advanced LIGO
Yi Pan
Physics , 2006,
Abstract: As currently designed, the signal-recycling cavity (SRC) in the Advanced-LIGO interferometer is degenerate. In such a degenerate cavity, the phase fronts of optical fields become badly distorted when the mirror shapes are slightly deformed due to mirror figure error and/or thermal aberration, and this causes significant loss of the signal power and the signal-to-noise ratio (SNR) of a gravitational wave event. Through a numerical modal simulation of the optical fields in a simplified model of an Advanced-LIGO interferometer, We investigate the loss of the SNR and the behavior of both the carrier and signal optical fields, with the SRC at various levels of degeneracy. We show that the loss of the SNR is severe with a degenerate SRC, and a nondegenerate SRC can be used to solve this problem. We identify the optimal level of degeneracy for the SRC, which is achieved when the cavity Gouy phase is between 0.2 and 1.3 radians. We also discuss possible alternative designs of the SRC to achieve this optimal degeneracy.
Teaching Parallel Programming Using Both High-Level and Low-Level Languages
Yi Pan
Computer Science , 2001,
Abstract: We discuss the use of both MPI and OpenMP in the teaching of senior undergraduate and junior graduate classes in parallel programming. We briefly introduce the OpenMP standard and discuss why we have chosen to use it in parallel programming classes. Advantages of using OpenMP over message passing methods are discussed. We also include a brief enumeration of some of the drawbacks of using OpenMP and how these drawbacks are being addressed by supplementing OpenMP with additional MPI codes and projects. Several projects given in my class are also described in this paper.
An Energy-Aware Clustering Approach for Wireless Sensor Networks  [PDF]
Peter K. K. Loh, Yi Pan
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.22015
Abstract: Energy conservation is an essential and critical requirement for a wireless sensor network with battery oper-ated nodes intended for long term operations. Prior work has described different approaches to routing protocol designs that achieve energy efficiency in a wireless sensor network. Several of these works involve variations of mote-to-mote routing (flat routing) while some make use of leader nodes in clusters to perform routing (hierarchical routing). A key question then arises as to how the performance of an energy-aware, flat routing protocol compare with that of one based on hierarchical routing. This paper demonstrates a hierarchical routing protocol design that can conserve significant energy in its setup phase as well as during its steady state data dissemination phase. This paper describes the design of this protocol and evaluates its performance against existing energy-aware flat routing protocols. Simulation results show that it exhibits competitive performance against the flat routing protocols.
A Priority Queuing Model for HCF Controlled Channel Access (HCCA) in Wireless LANs  [PDF]
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.21004
Abstract: Recently, there has been a rapid growing interest in new applications requiring quality of service (QoS) guarantees through wireless local area networks (WLAN). These demands have led to the introduction of new 802.11 standard series to enhance access medium supporting QoS for multimedia applications. However, some applications such as variable bit rate (VBR) traffic address some challenges in the hybrid coordination function (HCF) nominated to provide QoS. This paper presents a novel priority queuing model to analyze a medium access in the HCF controlled channel access (HCCA) mode. This model makes use of a MAP (Markovian Arrival Process)/PH (Phase Type)/1 queue with two types of jobs which are suitable to support VBR traffic. Using a MAP for traffic arrival process and PH distribution for service process, the inclusion of vacation period makes our analysis very general and comprehensive to support various types of practical traffic streams. The proposed priority queuing model is very useful to evaluate and enhance the performance of the scheduler and the admission controller in the HCCA mechanism.
Evaluating the appropriateness and consequences of test use
Colombian Applied Linguistics Journal , 2009,
Abstract: this paper addresses the issue of whether it is appropriate for universities or junior colleges to set foreign language proficiency requirements for graduation and offers a historical review of the relationship of test validity and test use. examples of how to evaluate the appropriateness and consequences of test use are presented in order to discover what factors must be taken into account that contributes to the decision-making process. finally, a model that specifies what evidence needs to be collected in support of a valid test decision is offered to help make decisions of test use more convincing and accordingly more beneficial to those individuals and groups who are affected by the tests.
Yi-Ching Pan
TEFLIN Journal , 2009,
Abstract: : In light of the importance of understanding the social impacts of test use, this paper synthesizes the opinions and surveys of a variety of stakeholders, including businesses, the government, administrators, educators and students, regarding the English exit requirements, as reported in major local newspapers during the last decade. It then constructs implications in terms of considerations for those involved in the establishment of the requirements and provides insights and suggestions for other stakeholders. By doing so, it is hoped that this study will be beneficial to those who are active in the fields of English teaching, policy-making and test development.
A Closer Examination of Communicative Language Teaching
Yi-chun Pan
Studies in Literature and Language , 2013, DOI: 10.3968/j.sll.1923156320130602.5248
Abstract: This paper offers an in-depth discussion of communicative language teaching (CLT). It elaborates upon the construct and characteristics of CLT, and then documents research findings on CLT’s effectiveness. This paper then addresses components of a communicative curriculum, including the selection of materials, the design of activities, and the development of assessment formats.
Effects of Multi-Faceted Lexical Instruction on the TOEIC Listening Performance of Taiwanese EFL College Students
Yi-chun Pan
International Journal of English Linguistics , 2012, DOI: 10.5539/ijel.v2n6p71
Abstract: The current study conducted an investigation into the effects of multi-faceted lexical instruction on the TOEIC aural performance of Taiwanese EFL students at tertiary institutes of technology. A total of 47 Taiwanese first-year technological college students participated in this study. Throughout the course of a three-week preparatory English class, the students were provided with lexical instruction in which vocabulary was instructed in a multi-faceted way. Not only did students receive exposure to both single lexical items and multiword units, but they also engaged in a variety of oral activities. The findings of this research clearly indicate that the TOEIC aural performance of Taiwanese technological college students generally improved as a result of such instruction. This study also discussed unexplored issues to offer suggestions for future researchers.
Development of Radio Frequency Heating Technology for Shale Oil Extraction  [PDF]
Yi Pan, Can Chen, Shuangchun Yang, Lizhi Xiao
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.22008
Abstract: With the shortage of energy and the rise of crude oil in the world, the development of oil shale is gaining more attention globally. To solve the problem of traditional heat conduction with low efficiency and high cost for oil shale, a new technology called radio frequency (RF) heating (microwave heating) is introduced in this paper. Radio frequency electromagnetic (microwave) can do work directly on medium molecule of oil shale and change into heat energy, the transmission of which allows both inner and outer molecules heating simultaneously without heat conduction. Meanwhile, oil shale is a poor microwave absorbing material and microwave absorbents must be added to reach pyrolysis temperature. By this means, shale oil could be heated at a higher speed and kerogen will gradually be cracked into gas and oil. Then shale oil and gas will flow into the production wells through fractures generated by heating and be pumped up to the surface.
The Research and Application of Bright Spot Quantitative Interpretation in Deepwater Exploration  [PDF]
Yi He, Jitian Zhu, Yingzhao Zhang, Aiqun Liu, Guangchao Pan
Open Journal of Geology (OJG) , 2017, DOI: 10.4236/ojg.2017.74040
Abstract: Prospectors usually recognize the event with strong amplitude in seismic sections as bright spots. However, such a simple and rough method can’t distinguish whether these bright spots are related to favorable gas layer or water layer directly. In this paper, for the high correlation between reservoir gascontent and amplitude anomaly in research area, based on rock physical analysis of the wells drilled, using forward modeling technique respectively simulates and analyzes the seismic amplitude of gas layer and water layer. Then, combining the simulation result with corresponding statistics amplitude obtains the numerical relationship between each layer amplitude. At last, using the display technique directly recognizes the bright spots of gas layer in seismic profile and gets rid of those false bright spots caused by water layer, which improved the robustness in the bright spots interpretation and provided reliable basis for reducing exploration risks. Moreover, applying the method to the target zone, we obtain huge success.
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