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The Lithium Ion Battery Technology

  • Lee, Ki-Young
    • Carbon letters
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    • v.2 no.1
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    • pp.72-75
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    • 2001
  • The performance of Li-ion system based on LiCoO2 and Graphite is well optimized for the 3C applications. The charge-discharge mode, the manufacturing process, the cell performance and the thermal reactions affecting safety has been explained in the engineering point of view. The energy density of the current LIB system is in the range of 300~400 Wh/l. In order to achieve the energy density higher than 500 Wh/l, the active materials should be modified or changed. Adopting new high capacity anode materials would be effective to improve energy density.

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Adaptive MPEG Traffic Prediction

  • Jung, Souhwan;Yoo, Jisang
    • The Journal of the Acoustical Society of Korea
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    • v.16 no.3E
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    • pp.7-13
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    • 1997
  • This paper addresses traffic prediction issues on MPEG. A new adaptive traffic prediction scheme is proposed using MPEG picture characteristic that picture traffic depends on the coding mode of that picture, that is, I, P, and B mode. Our prediction scheme, which is based n picture decomposition (PD) and the cross-correlation of the different types of pictures, has better performance in predicting bursty MPEG traffic than that of the first-order autoregressive (AR) prediction scheme. Our simulation results show that the performance is further improved about 15% by utilizing the cross-correlations between pictures.

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Issues When Estimating Fatigue Life of Structures

  • Lee, Ouk-Sub;Chen, Zhi-wei
    • International Journal of Precision Engineering and Manufacturing
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    • v.1 no.2
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    • pp.43-47
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    • 2000
  • When estimating fatigue crack growth (FCG) life of structures, the use of crack growth models and knowledge of the values of their corresponding parameters are of vital importance. Inconsistency in using models with appropriate parameters can lead to enormous errors in FCG life prediction. In this paper examples are analyzed and compared with test results to show the possible problems, Consistency checks are necessary for avoiding some pitfalls, and also necessary for verifying the correct performance and accuracy of the used computer program.

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A Review on Approach of International Trade Practice Under RFID System Environment (RFID 시스템 환경 하에서 무역업무의 접근에 관한 고찰)

  • Seo, Gab-Sung
    • International Commerce and Information Review
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    • v.10 no.4
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    • pp.153-169
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    • 2008
  • The purpose of this paper is to review the major issues of between electronic trade and Ubiquitous computing. The rapidly developed environment by ubiquitous computing make the paradigm form e-trade to u-trade. This Article suggests an a-trade performance framework based on both field and literatures surveys. We propose some research subjects as well as practical implications for improving the performance of global c-trade under ubiquitous.

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Fault-tolerant design of packet switched network with unreliable links (불안정한 링크를 고려한 패킷 교환망 설계)

  • 강충구
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.2
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    • pp.447-460
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    • 1996
  • Network optimization and design procedures often separate quality of service (QOS) performance measures from reliability issues. This paper considers channel allocation and flow assignment (routing) in a network subject to link failures. Fault-tolerant channel allocation and flow assingments are determined which minimize network cost while maintaining QOS performance requirements. this approach is shown to yield significant network cost reductions compared to previous heuristic methods used in the design of packet switched network with unreliable links.

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An Enhanced Mobile IP Handoff Mechanism using Routing Optimization and Binding Extension (경로설정 최적화와 바인딩 확장을 이용한 개선된 Mobile IP 핸드오프 기법)

  • 오현우
    • Proceedings of the Korea Society for Simulation Conference
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    • 1999.10a
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    • pp.127-132
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    • 1999
  • A mobile IP is proposed to support host mobility over the current Internet. One of the most important issues on the host mobility is location and routing schemes that allow mobile hosts to move effectively from one site to another. In a Mobile IP environment, frequent handoffs are likely to degrade the performance by minimizing the loss of datagrams during handoffs. The handoff scheme is using routing optimization and binding extension to improve the performance by minimizing the average transfer delay of messages and packet loss. Simulation details show the improvement of transport delays and packet loss rate.

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The Analysis on the Safety Plan of Train Performance Tests KHST (KHST 차량성능 시험에 대한 안전체계에 의한 분석)

  • Lee, Chan-Woo;Choi, Sung-Hoom
    • Proceedings of the KSR Conference
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    • 2003.10c
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    • pp.312-315
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    • 2003
  • The KHST vehicle, with the maximum speed of 350km/h, is being developed under the en national R&D project and we investigate the performance test procedure of the vehicle considering the safety plan. First, important issues in the safety plan for the KTX vehicle are reviewed and then they are reflected in the test procedure for the KHST vehicle.

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E-Business Strategies : The Antecedents and Consequences (e 비즈니스 전략 : 선행요인과 결과)

  • Koo, Chul-Mo;Kim, Yona-Jin;Nam, Ki-Chan
    • Journal of the Korean Operations Research and Management Science Society
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    • v.31 no.4
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    • pp.49-68
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    • 2006
  • E-business strategy has interests in Issues of strategic positioning and its impact on firm performance. These studies address the environmental factors as antecedents to strategic decision makings and its consequences such like firm performance. However most studies has not considered the role of business models In explaining e-business firm performance. We adopt Porter's generic strategies to the e-business context. We Identify business models and e-business environmental factors as antecedents and then examine these factors Influence on firm performance. We find that uncertainty of environment has a negatively related to the strategic choices of e-Business firms; in contrast, market turbulence positively affects the level of adoption of all the strategies. Among the strategies, marketing differentiation only makes an Impact on firm performance.

Incorporating nonstructural finish effects and construction quality in a performance-based framework for wood shearwall design

  • Kim, Jun Hee;Rosowsky, David V.
    • Structural Engineering and Mechanics
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    • v.21 no.1
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    • pp.83-100
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    • 2005
  • This paper presents results from a study to extend a performance-based shearwall selection procedure to take into account the contributions of nonstructural finish materials (such as stucco and gypsum wallboard), construction quality issues, and their effects on the displacement performance of engineered wood shearwalls subject to seismic loading. Shearwall performance is evaluated in terms of peak displacements under seismic loading (characterized by a suite of ordinary ground motion records) considering different combinations of performance levels (drift limits) and seismic hazard. Shearwalls are analyzed using nonlinear dynamic time-history analysis with global assembly hysteretic parameters determined by fitting to actual shearwall test data. Peak displacement distributions, determined from sets of analyses using each of the ground motion records taken to characterize the seismic hazard, are postprocessed into performance curves, design charts, and fragility curves which can be used for risk-based design and assessment applications.

A Performance Evaluation Mode1 for Information Systems using the Balanced Scorecard and the Value Chain : A Case Study (BSC와 가치사슬을 이용한 정보시스템의 성과 측정 방법 : 제조업체 사례분석)

  • 최경현;김태균
    • Journal of the Korean Operations Research and Management Science Society
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    • v.27 no.2
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    • pp.63-79
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    • 2002
  • During the last decade many enterprises spent a huge amount of money for investment on Information Technology (IT) & Information System (IS) to attain competitive advantage and to maximize their business performance by satisfying the various requirements of customers. Under such circumstances, methodologies for evaluating IT impact on business performance are very important issues for strategic decision making on investment. In this study, we propose a performance evaluation model that adopts the concept of the Balanced Scorecard (BSC) and the Value Chain to analyze the financial impact and non-financial impact of IT & IS at each critical work area. This model combines the 4 evaluation areas from BSC and 6 critical work areas from Value Chain and measures the Key Performance Indicator (HPI) and the effect of KPI. Also, we present a case study of which the evaluation model has been conducted on a major manufacturing company. finally. we address some important notes to improve the IT & IS performances in the real-world.