• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.911-925
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• 1996

Emerging service classes need an error model which efficiently satisfies the requirements for each media and application. However limited flexibility in the error control has been provided. Therefore we propose a new error control model which applies error control scheme per media flexibly with respect to ETL(Error Tolerance Leverl) and delay. In order to select the error control scheme in this model, the attributes of media(i.e., ETL, isochronism), the attributes of application(i.e., delay) and environment parameters(i.e., packet loss ration, network types, connection modes of the application) are considered as effect factors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1125-1130
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• 2005

This paper presents a method for inter-sheet spacing control in a flexible media handling device. In order to verify the performance of inter-sheet spacing control by experiment, system of section structure is introduced in the first place. In the introduced system, each section is driven by different servo motor for independent section freedom. And suitable inter-sheet spacing control algorithm that is more optimal than conventional inter-sheet spacing control algorithm is proposed. Finally experiments are performed to confirm the performance of inter-sheet spacing control. And two inter-sheet spacing control algorithms, conventional and proposed, are compared with each other.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.906-911
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• 2004

In the development of sheet-handling machinery, it is important to be able to predict the italic and dynamic behavior of the sheets with a high degree of reliability because the sheets are fed and stacked at such a high speed. In this paper, a spring-mass-beam model is introduced. This model consists of rotational springs, shear springs and masses. The formulations for static and dynamic behavior of sheets are introduced. And some simulations are presented for static and dynamic cases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.564-568
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• 2005

As functional requirements of automatic office machines like printers, ATMs, copying machines are on a trend for the higher speed and precision, extensive technical advances are being developed and implemented in the industry. Media transport system is a device to convey a sheet of paper in ATMs and printers. The stability of media transport system is a matter of concern as their operating throughput rapidly increases. And defects of belts or rollers in a transport system directly affect the level of stability of the system. Therefore an automatic diagnostic system for predicting various defects is necessary for the stable operation of the media transport system. A simulation based on multi-body dynamics has been done for a feasibility study of a system design for the defect anticipation.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.59-63
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• 2005

Nowadays, various approaches are performed to increase the storage capacity of optical storage device. One of the promising candidates is using the high NA lens. By using high NA lens, the beam spot size can be reduced which will lead to increase the storage density. This paper proposes a double cantilever beam type bimorph PZT actuator for fine motion that can control the gap between the flexible media and optical pickup which uses high NA lens. Mathematical model is derived by using Hamilton's principle and the model is verified by finite element analysis and experiment. Position controller is designed and its performance is evaluated by experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.608-608
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• 2008

• Journal of KSNVE
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• v.17 no.2 s.86
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• pp.29-34
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• 2007

• 한국경영정보학회:학술대회논문집
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• 2007.11a
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• pp.257-262
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• 2007

본 연구에서는 온라인 커뮤니케이션 매체특성이 그룹의 협력과 프로젝트 성과에 미치는 영향을 메신저와 e-Learning시스템을 대상으로 비교분석하였다. 독립변수인 커뮤니케이션 매체특성은 풍부성(richness), 동기성(synchronization), 유연성(flexibility), 이용편이성(easy of use)으로 구분하였으며, 이 매체특성들이 그룹의 협력에 미치는 영향과 궁극적으로 프로젝트 성과에 미치는 영향을 밝혀내고자 하였다. 검증을 위해 실제 그룹 프로젝트를 수행하는 실험 설계를 이용하였다. 연구결과 메신저를 주로 이용하여 프로젝트를 수행한 그룹에서는 커뮤니케이션 매체특성으로 풍부성과 이용편이성이 협력을 증진시키는 것으로 밝혀졌으며, e-Learning 시스템을 주로 이용한 그룹에서는 이용 편이성만이 협력을 증진시켰으며, 궁극적으로 프로젝트 성과를 향상시키는 것으로 밝혀졌다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7A
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• pp.709-716
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• 2006

본 논문에서는 무선 센서 네트워크의 다양한 응용 환경 및 상/하향 트래픽 스트림의 특성에 따라 유연하게 적용할 수 있는 새로운 매체접근제어 프로토콜을 제안한다. HiPERMAC(Hierarchically-Paired Evolutionary Radio MAC)이라고 불리는 제안 매체접근제어방식은 다양한 클러스터링 방식에 의하여 구축된 다 계층 (Hierarchical) 네트워크에서 별도의 대역 확산 전송방식이나 다수의 주파수 채널을 사용하지 않고, 단 2개의 시간 구간을 공간적으로 재활용하여 N 계층의 개별적인 통신이 가능한 구조를 제공한다. 즉, 제안방식은 단일 주파수 개념을 이용하여 계층화된 우선 센서 네트워크를 계층적 이중화(Hierarchically-Paired)하고 이때 발생하는 클러스터 간 상호 간섭의 요인들을 시간 및 공간적으로 분리하여 망 확장성과 자원 효율성을 극대화 하는 새로운 매체접근 제어 방식 이다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.380-383
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• 2006

The media transport system is used in a printer, a ATM(Automated Tellor Machine), and so on. The media transport system has many problems through miniaturization and rapid transportation of these machines. In the paper feeding mechanism, it is important to feed the sheet without jamming under any conditions. To avoid sheet jamming, first we need to predict the behavior of the sheet exactly. In this paper, the analysis of media behavior is based on J. Stolte's studies. In all of OA machines, a flexible beam or plate is pushed from the channel. The motion may be constrained by guides. This leads to a transient and geometrically nonlinear problem. The behavior of paper is simulated by dynamic elastica theory. The shape of guide is represented by parametric cubic curve. But J. Stolte's studies did not considered contact condition between sheet and guide. So Klarbring's Model. will be applied. And the analysis of flexible media has to include aerodynamic effect for more exact behavior analysis, because the flexible media can be deformed drastically by a little force. Therefore aerodynamic force must be applied to the governing equation. Lastly, the simulation of this model is performed, and the experiment is performed for verification of this model. The experimental results of low exit velocity are consistent with the simulation results, however experimental results of high exit velocity do not agree well with analytical results. The reason is that there may be other effects like nip Phenomena