• 산업공학
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• 제16권4호
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• pp.485-495
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• 2003

This paper reports on the application of the integration of mathematical programming model and database in a decision support system (DSS) for the planning of the multi-reservoir operating system. The DSS is based on a multi-objective, mixed-integer goal programming (MIGP) model, which can generate efficient solutions via the weighted-sums method (WSM). The major concern of this study is seamless, efficient integration between the mathematical model and the database, because there are significant differences in structure and content between the data for a mathematical model and the data for a conventional database application. In order to load the external optimization results on the database, we developed a systematic way of naming variable/constraint so that a rapid identification of variables/constraints is possible. An efficient database structure for planning of the multi-reservoir operating system is presented by taking advantage of the naming convention of the variable/constraint.

• 한국항해항만학회지
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• 제28권8호
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• pp.673-678
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• 2004

전자해도의 표준 형식인 S-57은 수로 데이타의 교환을 위한 표준이다. 이에 따라 제작된 항해용 디지털 해도를 전자해도(ENC: Electronic Navigational Chart)라 하며, 전자해도를 공간 정보의 표현에 적절한 컴퓨터 자료 구조로 변환 한 것을 SENC(System ENC)라 부른 다. SENC는 시스템 제조업체마다 고유한 알고리듬으로 제작되는데, ECDIS(Electronic Chart Display and Information System) 성능에 주요한 역할을 하는 요소임에도 불구하고 아직까지 SENC의 구조의 설계 및 구현에 관한 연구는 발표된 바가 없는 실정이다. 본 연구에서는 새로이 고안한 Mesh 구조를 이용한 SENC 구조를 설계하였고, 이를 Display 할 수 있는 시스템을 구현하여 PDA 및 데스크탑 컴퓨터에서 동작 결과를 확인하였다.

• Geomechanics and Engineering
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• 제2권4호
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• pp.229-252
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• 2010

In this paper, Soil-Structure Interaction (SSI) effect is investigated using a new and integrated approach. Faster solution of time dependant differential equation of motion is achieved using numerical representation of wavelet theory while dynamic Infinite Elements (IFE) concept is utilized to effectively model the unbounded soil domain. Combination of the wavelet theory with IFE concept lead to a robust, efficient and integrated technique for the solution of complex problems. A direct method for soil-structure interaction analysis in a two dimensional medium is also presented in time domain using the frequency dependent transformation matrix. This matrix which represents the far field region is constructed by assembling stiffness matrices of the frequency dependant infinite elements. It maps the problem into the time domain where the equations of motion are to be solved. Accuracy of results obtained in this study is compared to those obtained by other SSI analysis techniques. It is shown that the solution procedure discussed in this paper is reliable, efficient and less time consuming as compared to other existing concepts and procedures.

• ETRI Journal
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• 제32권4호
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• pp.493-502
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• 2010

The operation time of an encoder is one of the critical implementation issues for satisfying the timing requirements of Long Term Evolution (LTE) systems because the encoder is based on binary operations. In this paper, we propose a design and implementation of a latency efficient encoder for LTE systems. By virtue of 8-bit parallel processing of the cyclic redundancy checking attachment, code block (CB) segmentation, and a parallel processor, we are able to construct engines for turbo codings and rate matchings of each CB in a parallel fashion. Experimental results illustrate that although the total area and clock period of the proposed scheme are 19% and 6% larger than those of a conventional method based on a serial scheme, respectively, our parallel structure decreases the latency by about 32% to 65% compared with a serial structure. In particular, our approach is more latency efficient when the encoder processes a number of CBs. In addition, we apply the proposed scheme to a real system based on LTE, so that the timing requirement for ACK/NACK transmission is met by employing the encoder based on the parallel structure.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.907-909
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• 2016

본 논문에서는 DTN에서 UAV 편대를 이용한 효율적인 네트워크 구조를 제안한다. 기존 MANET에서 불안정한 종단간 연결성으로 인한 문제를 해결하기 위해 제안된 DTN은 Store-Carry-Forward 방식을 사용하여 통신한다. Store-Carry-Forward 방식의 통신은 종단간의 연결 없이도 중계 노드가 확보되면 번들 계층을 통해 메시지를 저장하여 목적 노드까지 손실 없이 메시지를 전달한다. 이러한 라우팅 구조는 재해재난 상황이나 전쟁 지역과 같이 네트워크 기반시설이 없는 곳에서도 네트워크를 구성하는 데 유리하기 때문에 현재 많은 연구가 진행되고 있다. 본 논문은 그런 연구의 일환으로 UAV 편대를 이용하여 유동적인 환경에서 더 효율적인 네트워크 구조를 제안한다. 제안하는 방안은 센서로써 작동하는 이질적인 노드들의 환경 정보 이용해 UAV 분대를 조직하여 안정적인 통신이 가능하도록 한다.

• 한국컴퓨터산업학회논문지
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• 제2권8호
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• pp.1089-1098
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• 2001

구조적 문서가 가지는 구조 정보는 문서로의 다양한 접근경로를 나타내는데 사용될 수 있다. 이러한 구조적 문서가 가지는 구조 정보를 활용하기 위해서는 문서의 구조에 대해서 색인을 해야 한다. 이때 내용색인뿐만 아니라 문서마다 구조정보를 저장하므로 색인에 필요한 공간이 커진다. 그러므로, 색인공간 오버헤드를 최소화시키면서도 엘리먼트간의 포함관계나 순서 등 문서의 순수 구조에 바탕을 둔 순수 구조 질의를 처리할 수 있어야 한다. 본 논문에서는 색인공간 오버헤드를 최소화하면서도 여러 유형의 구조 관련 질의를 효율적으로 처리할 수 있는 구조 색인 구조와 GDIT자료구조를 제시한다. 제안하는 구조 색인 구조는 문서에 존재하는 가장 하위 엘리먼트만을 색인대상으로 하며, 검색엘리먼트가 존재하는 문서개수에 영향을 받지 않는다. 그리고 이 색인구조를 바탕으로 순수 구조에 대한 질의 처리과정을 보이고 색인공간에 대해 그 성능을 평가한다. 제안된 색인 구조는 GDIT개념［2］에 바탕을 두고, GDIT기반의 색인기법을 사용한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.574-575
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• 2008

In this paper, we have explored current hierarchy for demand side management programs and proposed an efficient structure for the successful implementation of DSM programs in Korea.

• 전자공학회논문지B
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• 제29B권8호
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• pp.54-65
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• 1992

A huge amount of multiplications is required for 2-D filtering on the image data, making it difficult to implement a real-time quincuncial interpolator. In this paper, efficient design technique and VLSI structures for 2-D multipleierless filter are presented. In the filter design, by introducing an efficient scheme for discretizing the frequency response of the prototype filter, it is shown that a significant amount of the computational burden required in the conventional techniques, such as local search, branch and bound techniques, could be saved. In the case of 5$\times$5 filter, it is found that the design technique described in this paper could save about 80% of the computation time, compared to the conventional methods, while providing a comparable performance. For a hardware implementation, two different VLSI structures for 2-D multiplierless filter are also introduced in the paper : One is for block parallel processing and the other for scan-line parallel processing. In both structure, the AP(area-period) figure improves over Wu's structure[4].

• 한국멀티미디어학회논문지
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• 제13권12호
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• pp.1748-1759
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• 2010

We extend the octree subdivision process from Cartesian coordinates to spherical coordinates to develop more efficient space-partitioning structure for surface models. As an application of the proposed structure, we apply the octree subdivision in spherical coordinates ("S-Octree") to geometry compression in progressive mesh coding. Most previous researches on geometry-driven progressive mesh compression are devoted to improve predictability of geometry information. Unlike this, we focus on the efficient information storage for the space-partitioning structure. By eliminating void space at initial stage and aligning the R axis for the important components in geometry information, the S-Octree improves the efficiency in geometry information coding. Several meshes are tested in the progressive mesh coding based on the S-Octree and the results for performance parameters are presented.

• Structural Engineering and Mechanics
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• 제46권2호
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• pp.231-244
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• 2013

An efficient method is proposed here to identify multiple damage cases in structural systems using the concepts of flexibility matrix and strain energy of a structure. The flexibility matrix of the structure is accurately estimated from the first few mode shapes and natural frequencies. Then, the change of strain energy of a structural element, due to damage, evaluated by the columnar coefficients of the flexibility matrix is used to construct a damage indicator. This new indicator is named here as flexibility strain energy based index (FSEBI). In order to assess the performance of the proposed method for structural damage detection, two benchmark structures having a number of damage scenarios are considered. Numerical results demonstrate that the method can accurately locate the structural damage induced. It is also revealed that the magnitudes of the FSEBI depend on the damage severity.