• 정보보호학회논문지
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• 제23권2호
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• pp.279-286
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• 2013

최근 전력 수요의 급증으로 인한 전력난은 효율적 전력 사용을 위한 스마트그리드 기술의 중요성을 부각시키고 있다. 스마트그리드 네트워크의 필수구성요소인 스마트미터기의 가용성 취약점에 대한 실험적 내용이 보고되고 있다. 따라서 안전한 스마트그리드의 실현가능성을 위한 가용성 보호 메커니즘 고안이 필수불가결하다. 본 논문에서는 스마트그리드 구조 및 트래픽패턴의 특징 분석을 통해 스마트미터기에 대한 가용성 침해 공격을 탐지하고, 이상 트래픽을 발생하는 공격노드를 검출할 수 있는 메커니즘을 제안한다. 제안하는 탐지 메커니즘은 공격 탐지를 수행하는 시스템의 탐지 부하를 줄이고 적은 샘플 수에도 높은 탐지율을 제공하기 위해 근사엔트로피 기법을 사용한다. 또한 공격노드가 공격트래픽에서 변경할 수 없는 물리정보(CIR 또는 RSSI 등)를 이용하여 공격 탐지 및 공격노드 검출을 수행한다. 마지막으로 본 논문 제안 기법에 대한 시뮬레이션 결과, 탐지 성능과 실현가능성을 보인다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.911-916
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• 2012

It is important to identify dynamic characteristics of nuclear fuel components. Since the fuel always exposed to turbulent flow, the dynamic contact between grids and rods is one of the fuel failure modes. The dynamic behavior of grids in nuclear fuels is quite complex, since two pairs of spring support are placed in the limited space. The strap in a cell has single spring and double dimples and this paper focuses on investigation of the grid strap(Test Fuel Strap, TFS) vibration in one cell. To identify the grid strap vibration, modal analysis of the strap is performed using Finite Element Method (FEM). Modal testing on a $5{\times}5$ grid structure without rods is performed. The modal testing results are compared to analytic results. In addition, random test considering rod effect is performed about a $5{\times}5$ grid with rods under real contact condition in the air. Finally, the strap vibration of a $5{\times}5$ fuel bundle in INvestigation of Flow INduced vIbraTion(INFINIT) facility is measured in real fluid velocity condition without heating. It is shown that modal frequencies from the test are almost equal to those peak frequencies in the INFINIT test.

• Journal of Power Electronics
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• 제16권5호
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• pp.1904-1917
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• 2016

The moving average filter (MAF) is widely utilized to improve the disturbance rejection capability of phase-locked loops (PLLs). This is of vital significance for the grid-integration and stable operation of power electronic converters to electric power systems. However, the open-loop bandwidth is drastically reduced after incorporating a MAF into the PLL structure, which makes the dynamic response sluggish. To overcome this shortcoming, some new techniques have recently been proposed to improve the transient response of MAF-based PLLs. In this paper, a comprehensive performance comparison of advanced MAF-based PLL algorithms is presented. This comparison includes HPLL, MPLC-PLL, QT1-PLL, and DMAF-PLL. Various disturbances, such as grid voltage sag, voltage flicker, harmonics distortion, phase-angle and frequency jumps, DC offsets and noise, are considered to experimentally test the dynamic performances of these PLL algorithms. Finally, an improved positive sequence extraction method for a HPLL under the frequency jumps scenario is presented to compensate for the steady-state error caused by non-frequency adaptive DSC, and a satisfactory performance has been achieved.

• 한국정보통신학회논문지
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• 제22권8호
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• pp.1114-1122
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• 2018

본 연구에서는 그리드 네트워크에 대해서 정상적인 트래픽 예측에 의해서 설계된 자원 이외에 예측 불가능한 비상사태를 대비하기 위한 추가자원의 한계용량 설계에 관한 해석적 모델을 제안한다. 구체적으로는 그리드 네트워크 전체를 대상으로 한계용량을 산정하는 경우의 최솟값에 대한 상한을 예측하는 방법을 제안한다. 이를 위해서 본 논문에서는 그리드 네트워크를 그리드 그래프로 추상화하여 Roman domination number의 개념을 이용한 해석적 기법을 통해서 한계용량의 상한을 도출한다.

• 컴퓨터교육학회논문지
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• 제12권4호
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• pp.57-64
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• 2009

단백질 구조 비교는 각 단백질에 존재하는 수많은 원자들을 처리해야 하므로 많은 컴퓨팅 자원을 요구하는 작업이다. 이러한 작업을 처리하기 위한 접근법으로써 그리드 환경에서 시간 소모가 큰 계산 작업을 분산 처리하는 것이 널리 사용되어 왔다. 그러나 이러한 그리드 환경을 통제하는 것은 비전문가들에게 쉽지 않을 수 있다. 본 논문에서는 비전문가들도 쉽게 그리드 환경을 통제할 수 있는 JXTA 기반의 단백질 구조 비교 시스템을 제안한다. 쿼리 단백질과 비슷한 단백질들을 찾기 위해 사전처리 단계 와 인식단계로 구성된 기하학적 해싱 알고리즘이 사용되었다. 실험 결과에 의하면 주어진 쿼리 단백질 구조와 일치하는 단백질 구조를 시스템이 정확히 찾고 또한 제안된 시스템은 쉽게 단백질 다킹 문제를 해결하도록 확장될 수도 있다. 본 논문에서 제안하는 시스템은 비전문가들, 특히 생물학이나 화학을 전공하는 대학생들처럼 일반적으로 분산 시스템에 대한 숙련된 지식이 없는 사용자들에게 도움이 되리라 기대된다.

• 한국공간구조학회논문집
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• 제18권1호
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• pp.93-100
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• 2018

The retractable roof structures have actions of various types of loads and external forces depending on the retraction and operation conditions of the roof in terms of efficiency of control and maintenance as the aspect of structural plan. In particular, there is a need for studies on the establishment of retraction controlled wind velocity to maintain the stable control and usability of roof structure against strong winds or sudden gusts during the retraction of the roof. In this paper, it was intended to provide basic materials for the development of guidelines on the operation and maintenance of domestic retractable buildings with large space by analyzing the factors affecting the retraction controlled wind velocity for the overseas stadiums with the large spatial retractable roof structures where the sliding system was applied on the steel retractable systems. As a result, the controlled wind velocity tends to decrease as the retractable roof area increases. On the other hand, the controlled wind velocity tends to increase as the retraction time increases. In addition, in the space-grid roof structures, the spherical roof structures type showed the average controlled wind velocity of 10m/sec lower than that of 17.3m/sec for curved-roof structure type, and in the curved-roof structure type, the truss roof structure showed the average controlled wind velocity of 8.9m/sec which is lower than that of 17.3m/sec for the space for the space-grid roof structure.

• 대한전자공학회논문지
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• 제26권9호
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• pp.1428-1435
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• 1989

In this paper we propose a new algorithm which extracts spatial arrangement information of texture elements in structural textures. In the proposed algorithm, by the use of projection information in several directions obtained from the texture image we can get two directions which determine the texture structure and the parallelogram grid which isolates texture elements. The isolated texture elements are analyzed and used to synthesize texture images. Computer simulation shows that the proposed method can extract proper spatial structure of the texture element even when the texture image is highly corrupted by additive noise.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1996년도 정기총회 및 학술발표회
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• pp.32-32
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• 1996

Molecular docking studies were performed for a humanized HBV Pre-S2 antibody and its antigen adr. Antigen structure was taken from NMR experiment and antibody structure was determined by using homology technique. At first step, Grid search was performed for finding energetically favorable orientations antigen. (omitted)

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 추계학술대회 학술발표 논문집
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• pp.433-439
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• 1998

In this paper, we present an approach to the structure identification based on the input space partition methods and to the parameter identification by hybrid learning method in neuro-fuzzy system. The structure identification can automatically estimate the number of membership function and fuzzy rule using grid partition, tree partition, scatter partition from numerical input-output data. And then the parameter identification is carried out by the hybrid learning scheme using back-propagation and least squares estimate. Finally, we sill show its usefulness for neuro-fuzzy modeling to truck backer-upper control.

• 한국공간구조학회논문집
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• 제14권1호
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• pp.93-99
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• 2014

Deployable structure is a system on which the study is being actively performed in various fields including architecture field. However, There is little study which can enhance the practicality since the interpretation condition is difficult as the unstable structure in the architecture field. In this study, the Scissors system has been focused on among the Deployable structure. The structure was developed using the Scissors system and the Mock-up test was performed. Through this, the unfolding method was proposed and the practicability was surveyed through the specific design of the Test model. Also, the structure stability was reviewed through structure analysis of Mock-up test model. and stabilizing method was proposed.