• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2725-2728
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• 2003

The manipulability of robot provides useful Information for the design and path planning of robots. This paper shows an influence of joint velocities to acceleration of robot end-effector using a dynamic manipulability polytope. The main idea of this paper is that the dynamic manipulability polytope of robot can be divided to three intermediate polytope, the torque-dependant polytope, velocity-dependent polytope, and gravity-dependant polytope. The velocity-dependant polytope is made from the limits of robot joint velocities while the torque-dependant polytope is made from the limits of the joint torques. Combining of these two intermediate polytopes and considering the gravity-dependant polytope, the overall dynamic manipulability polytope of robot is obtained. This investigation will be useful on the field of space robot and high-speed application.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.99.1-99.1
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• 2016

The materials for an electronic packaging provide diverse important functions including electrical contact to transfer signals from devices, isolation to protect from the environment and a path for heat conduction away from the devices. The packaging materials composed of metals, ceramics, polymers or combinations are crucial to the device operating properly and reliably. The demand of effective charge and heat transfer continuous to be challenge for the high-speed and high-power devices. Nanomaterials including graphene, carbon nanotube and boron nitride, have been designed for the purpose of exploiting the high thermal, electrical and mechanical properties by combining in the matrix of metal or polymer. In addition, considering the inherent electrical and surface properties of graphene, it is expected that graphene would be a good candidate for the surface layer of a template in the electroforming process. In this talk, I will present recent our on-going works in nanomaterials for microelectronic packaging: 1) porous graphene/Cu for heat dissipations, 2) carbon-metal composites for interconnects and 3) nanomaterials-epoxy composites as a thermal interface materials for electronic packaging.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.109-117
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• 2000

This study aims at advancing waterfront of Pusan Port and attempting to establish an identity through studying characteristics of place in Pusan Port. The place is consisted of two elements ; orientation and identity, which is expressed clearly the environmental totality including the character and space. The urban waterfront is also one of the place pattern, and that is consist of land area, water area, and transit zone combining two areas. Although there are a lot of primary factors to be able to make the most of the character and identity in Pusan port, badly planned development prevents the plan promoting the sense of place in urban waterfront. The point in the waterfront development plan of Pusan Port is how to secure aminities based on Identity and Orientation; node, landmark, edge, path, district. The result of this study is for planners to develop more and systematic approaches which could utilize waterfront.

• Knowledge Management Research
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• v.10 no.2
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• pp.35-48
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• 2009

The paper proposes a quantitative causal ordering map (QCOM) to combine qualitative and quantitative methods in a framework. The procedures for developing QCOM consist of three phases. The first phase is to collect partially known causal dependencies from experts and to convert them into relations and causal nodes of a model graph. The second phase is to find the global causal structure by tracing causality among relation and causal nodes and to represent it in causal ordering graph with signed coefficient. Causal ordering graph is converted into QCOM by assigning regression coefficient estimated from path analysis in the third phase. Experiments with the prediction model of Korea stock price show results as following; First, the QCOM can support the design of qualitative and quantitative model by finding the global causal structure from partially known causal dependencies. Second, the QCOM can be used as an integration tool of qualitative and quantitative model to offerhigher explanatory capability and quantitative measurability. The QCOM with static and dynamic analysis is applied to investigate the changes in factors involved in the model at present as well discrete times in the future.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.256-260
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• 2001

본 논문은 광대역 무선통신환경에서 3GPP(3rd Generation Partnership Project)에 기반한 비동기 IMT-2000 시스템의 송수신 시스템을 구성하여 기지국의 수신성능을 분석하였다. 이동국과 기지국간의 Uplink 채널 환경을 고려하였으며, 기지국의 수신신호는 다중경로 페이딩(Multi-path Fading)과 다중접속간섭(Mult Access Interference : MAI)의 영향으로 성능일 열화된다. 이에 대한 대책으로 Array 안테나를 채용하였을 경우와 MRC-Diversity(Maximal Combining Diversity)를 채용하였을 경우의 수신성능을 동일한 환경에서 비교 분석하였으며, 각각의 시스템에 간섭제거기를 직렬로 비교분석하였다. 본 논문에서 적용한 Array 안테나는 수신 신호의 방향에 따라 적응적으로 추적하여 수신 SNR(Singnal-to-Noise power Ratio)을 최대로 형성하여 시스템의 성능을 개선하는 기법이며, 안테나의 방향성(Directivity :D=2.67)을 이용하는 3-element Array 안테나를 채용하였다. 최대비 합성 다이버시티 기법은 다이버시티 기법 중 수신효율이 가장 좋으며 가지수(L=2)를 함수를 사용하였다. 성능분석 결과 다중경로 페이딩과 다중접속간섭 환경에서 최대비 합성 다이버시티 기법이 Array 안테나보다 수신효율이 우수하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.153.1-153
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• 2001

This paper describes a development of rehabilitation training system for the postural balance control. A new rehabilitation training system, designated as a virtual cycling system, was developed to improve postural balance control by combining virtual reality technology with an unfixed bicycle. In this experiment, 20 normal adults were tested to investigate the influencing parameters of postural balance control. In order to evaluate the usefulness and the training effects of the system, several parameters Including path deviation, cycling velocity, cycling time, center of pressure, and head movement were evaluated and analyzed quantitatively. Also, to improve the effect of balance training, the visual feedback information related to the subject´s weight shift was ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.181.6-181
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• 2001

This paper describes a development of rehabilitation training system for the postural balance control. A new rehabilitation training system, designated as a virtual cycling system, was developed to improve postural balance control by combining virtual reality technology with an unfixed bicycle. In this experiment, 20 normal adults were tested to investigate the influencing parameters of postural balance control. In order to evaluate the usefulness and the training effects of the system, several parameters including path deviation, cycling velocity, cycling time, center of pressure, and head movement were evaluated and analyzed quantitatively. Also, to improve the effect of balance training, the visual feedback information related to the subject's weight shift was assessed to identify whether it was useful. It could be also known ...

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1477-1480
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• 2005

AOC-SS (Advanced Orthogonal Code-Spread Spectrum) modulation [1] is a flexible scheme to obtain a multi-rate transmission but PAPR (Peak-to-Average Power Ratio) increases in proportion to the number of AOCs and thus, the mapping technique is proposed to solve this problem. Moreover, by combining with space-time coding (STC), AOC-SS is capable of resistance to multi-path fading. The simulation programs have been performed to verify the validity of the suggested scheme.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.19-22
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• 2005

XML은 비즈니스 메시징, 웹사이트 정보 통합, 그리고 카탈로그 통합 등의 분야에서 다양한 데이터를 표현하기 위한 포맷으로 급격하게 성장했다. 그러나 XML 데이터의 형태가 고정되어 있지 않기 때문에 전통적인 질의 방법이 항상 정확한 결과를 보여주지는 않는다. 또한 객체 지향 DBMS가 이 영역에 적합한지의 여부는 아직 명확하지 않다. 따라서 XML 데이터를 효율적으로 검색하기 위해 기존의 관계형 DBMS와 연계하여 구조 유사성을 기반으로 하는 검색 기법이 연구되고 있다. 그 중 문서, 경로, 단어로 구성된 3차원 비트맵 인덱스를 이용한 검색 시스템은 다른 XML 문서 검색 시스템보다 훨씬 빠른 수행 속도를 보여주지만, 3차원의 메모리 구조를 사용하여 많은 저장공간을 필요로 하는 단점이 있다. 본 논문에서는 XML 문서를 저장할 때 경로들 사이의 유사성을 이용하여 XML 데이터의 경로를 통합하는 기법에 대해 소개한다. 이렇게 통합된 경로를 이용하여 생성하는 3차원 비트맵 인덱스는 그 크기가 상당히 줄어들게 되고, 기존의 연구에서 보여주었던 문제점들을 해결하게 되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.303-309
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• 2006

By combining the space-time diversity technique and iterative turbo codes, space-time turbo codes(STTCS) are able to provide powerful error correction capability. However, the multi-path transmission and iterative decoding structure of STTCS make the decoder very complex. In this paper, we propose a low complexity decoder, which can be used to decode STTCS as well as general iterative codes such as turbo codes. The efficient implementation of the backward recursion and the log-likelihood ratio(LLR) update in the proposed algorithm improves the computational efficiency. In addition, if we approximate the calculation of the joint LLR by using the approximate ratio(AR) algorithm, the computational complexity can be reduced even further. A complexity analysis and computer simulations over the Rayleigh fading channel show that the proposed algorithm necessitates less than 40% of the additions required by the conventional Max-Log-MAP algorithm, while providing the same overall performance.