• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제10권5호
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• pp.406-418
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• 2004

최근의 데이타 처리 환경은 빠르게 변화하고 있다. 특정 단체나, 기업 내에서 상호운용에 대한 고려 없이 서로 다른 목적에 의해서 개별적으로 도입되었던 여러 어플리케이션이나 시스템 등은 유연하고 빠른 처리를 위하여, 프로세스 차원에서 통합되고 연동되어야 할 필요성이 대두되고 있다. 추가 비용을 최소화하면서 통합에 대한 요구를 충족시킬 수 있는 좋은 방법 중 하나는 모든 플랫폼에서 사용 가능한 장치 비종속적인 데이타 형식이고 W3C(World Wide Web Consortium)의 문서 변환 표준인 XSLT (eXtensible Stylesheet Language Transformation)를 이용하여 필요에 따라 다른 형식의 데이타로 변환이 용이한 XML(extensible Markup Language)을 중심으로 통합하는 것이다. 이에 본 논문은 XML 문서의 구조적 정보를 정의하는 XML 스키마(Schema)를 통해 데이타를 제공하는 원본(Source)측과 데이타를 처리하고자 하는 목적(Destination)측의 구조를 나타내고, 이러한 구조정보와 데이타 매핑(Mapping)을 통해 원하는 형태의 구조관계를 정의하며, 정의된 정보를 기반으로 두 구조간의 변환 규칙을 정의한 XSLT 문서를 생성하는 XML 구조 변환 시스템을 설계하고 구현한다. 이렇게 생성된 XSLT 문서를 통해 데이타 처리를 필요로 하는 목적 측의 구조에 맞게 데이타가 재구성 되도록 변환한다. 이렇게, 특정 시스템이나 플랫폼과 관계없이 다양한 구조의 문서를 적용할 수 있게 되고 원하는 형태로의 의미 부여가 가능한 XSLT 문서를 생성하고, 이를 통한 문서간의 변환 처리를 제공하여 데이타의 상호 운용성(Interoperability) 및 확장성을 높이고 XML 문서처리 환경 구축에 기여하는데 목적을 두고 있다.

• 한국정보과학회논문지:데이타베이스
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• 제34권4호
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• pp.328-342
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• 2007

본 논문에서는 데이타의 갱신이 빈번한 상황에서 데이타의 갱신을 효율적으로 처리하기 위한 색인 기법을 제안한다. 제안하는 색인구조는 대표적인 공간 분할 색인 기법 중 하나인 KDB-트리를 기반으로 하고 있으며, 캐시의 활용도를 높이기 위한 데이타 압축 기법과 포인터 제거 기법을 제안한다. 제안하는 기법의 우수성을 보이기 위해서 기존의 대표적인 캐시를 고려한 색인 구조중 하나인 CR-트리와 실험을 통해 성능을 비교하였으며, 성능평가 결과, 제안하는 색인 구조는 삽입 성능과 갱신 성능, 캐시 활용도 면에서 기존 색인 기법에 비해 각각 85%, 97%, 86% 의 성능이 향상되었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.81-88
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• 2000

Unlike structures in the air, the vibration analysis of a submerged or floating structure such as offshore structures or ships is possible only when the fluid-structure interaction is understood, as the whole or part of the structure is in contact with water. Specially, the importance of the added mass is not necessary to say like the submerged vehicle, all of the hull body, is positioned in the water. This paper introduce two method to find natural frequency in consideration of fluid-structure modal coupled vibration analysis. The purpose of this study is to analyze of the vibration characteristic of submerged vehicle to obtain the anti-vibration design data, which could be used in the preliminary design stage data. Underwater pressure hull of submerged vehicle is used as the model of this study. The F.E.M model is meshed by shell and beam element. Also, considering of the inner hull weight, mass element is distributed in the direction of hull length. Numerical calculations are accomplished using the commercial B.E.M code. The characteristics of natural frequency(eigenvalues), mode shape(eigenvectors) and frequency-displacement response are analyzed. The results of this study will be used as the useful design data in preliminary anti-vibration design stage.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2004년도 춘계 종합학술대회 논문집
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• pp.529-534
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• 2004

한국과학기술정보연구원(KISTI)에서는 무기결정구조데이터베이스(ICSD, Inorganic Crystal Structure Database)를 국내 화학, 재료 관련 연구 개발자들에게 무료로 제공하고자 하였다. 그리하여 독일의 FIZ Karlsruhe로부터 ICSD의 국내 라이센스를 받아 이 데이터를 사용하여 데이터베이스를 구축하고 웹 기반의 새로운 정보 검색 시스템을 개발하였다. 웹상에서 여러 가지 방법으로 결정구조 정보를 검색 할 수 있는 다양한 메뉴를 구성하였으며 검색 결과에서는 결정구조에 관한 수치 정보 뿐 아니라 X-선 회절 패턴 및 3차원 결정구조 그래픽도 함께 제공하게 되었다. 이 시스템은 앞으로도 데이터의 계속적인 추가, 갱신이 이루어질 예정이며 연구자들이 편리하고 신속하게 정보를 제공받을 수 있도록 검색시스템을 향상시켜 나갈 것이다.

• Smart Structures and Systems
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• 제24권2호
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• pp.257-266
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• 2019

The benefit of data fusion in improving the performance of Higher Order Sliding Mode (HOSM) observer is brought out in this paper. This improvement in the performance of HOSM observer, resulted in the improvement of active vibration control of a piezo actuated structure, when controlled by a Discrete Sliding Mode Controller (DSMC). The structure is embedded with two piezo sensors for measuring the first two vibrating modes. The fused output of sensors is applied to the HOSM observer for generating state estimates, these states generated are applied to the DSMC, designed for the fourth order linear time invariant model of the structure. In the simulation study, the structure is excited at the first and second mode resonance. It is found that better vibration suppression is obtained, when the states generated by the fused output of sensors is applied as controller input, than the vibration suppression obtained by applying the states generated by using individual sensor output. The closed loop performance of DSMC obtained with HOSM observer is compared with the closed loop performance obtained with the conventional observer. Results obtained shows that better vibration suppression is obtained when the states generated by HOSM observer is applied as controller input.

• 반도체디스플레이기술학회지
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• 제8권2호
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• pp.59-62
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• 2009

In order to check the validation of LC simulation, 0.7 inch LCOS panel in full-HD resolution was fabricated and used for the electro-optical measurement. Compared the measured data with the calculated data, the averaged difference was 1.72% under 0 ~ +6 V bias on pixel electrode. To improve the optical characteristics of full-HD LCOS panel, the planar structure and trench structures (0.1 um, 0.2 um and 0.3 um-in-depth) between adjacent pixels were investigated with LC simulation. The planar structure showed the higher reflectance and faster reflectance-voltage response time than the trench structure. The optical fill factor and contrast ratio of planar structure were also higher than those of trench structures. As compared 1 um-in-depth trench structure resembled to the real structure with the planar structure, the optical fill factor was improved by 1.15% and the contrast ratio was improved by 5.26%. In order to minimize the loss of luminance and contrast ratio, the planar structure need to be applied between adjacent pixels.

• The Journal of Asian Finance, Economics and Business
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• 제8권1호
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• pp.71-79
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• 2021

This study investigates the capital structure policy among Indonesian public companies. Previous studies suggest that capital structure policy could follow either static or dynamic behavior. The sample data used in this study was companies in the manufacturing sector, divided into three sub-sectors: the basic and chemical industry, miscellaneous industry, and the consumer goods industry. This study uses panel data from 2010 to 2018, with the Generalized Least Square (GLS) method and compared whether the fixed effect model is better than the common effect model. The results show that the dynamic and non-linear model tests can explain the capital structure determinants than the static and linear models. The dynamic model shows that the capital structure of a certain year is influenced by the capital structure of the previous year. The findings indicate that the company performs some adjustments in its capital structure policy by referring to the previous debt ratio, which implies support to the trade-off theory (TOT). The study also shows that profitability, tangible assets, size, and age explain the variation of capital structure policy. The patterns on the dynamic and non-linear confirm that capital structure runs in a nonlinear pattern, based on the sector, company condition, and the dynamic environment.

• Earthquakes and Structures
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• 제12권6호
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• pp.653-663
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• 2017

A seismic margin assessment evaluates how much margin exists for the system under beyond design basis earthquake events. Specifically, the seismic margin for the entire system is evaluated by utilizing a systems analysis based on the sub-system and component seismic fragility data. Each seismic fragility curve is obtained by using empirical, experimental, and/or numerical simulation data. The systems analysis is generally performed by employing a fault tree analysis. However, the current practice has clear limitations in that it cannot deal with the uncertainties of basic components and accommodate the newly observed data. Therefore, in this paper, we present a Bayesian-based seismic margin assessment that is conducted using seismic fragility data and fault tree analysis including Bayesian inference. This proposed approach is first applied to the pooltype nuclear research reactor system for the quantitative evaluation of the seismic margin. The results show that the applied approach can allow updating by considering the newly available data/information at any level of the fault tree, and can identify critical scenarios modified due to new information. Also, given the seismic hazard information, this approach is further extended to the real-time risk evaluation. Thus, the proposed approach can finally be expected to solve the fundamental restrictions of the current method.

• 농촌계획
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• 제23권2호
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• pp.43-54
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• 2017

When an age of low growth and population decline, population migration plays an important role in spatial structure of region. There have been many researches on migration and regional spatial structure. The purpose of this study is to examine the changes of Gwangju and Jeonnam region's spatial structure and central area using social network analysis methods. For analysis it was used that population and migration data and passenger OD(Origin and Destination) travel data released by Statistics Korea and Korea Transport Database(KTDB). Using Gephi 0.8.2, migration and passenger OD networks were visualized, and this describe network flow and density. The results of the network centrality analysis show that the most populated village is not always network center though population mass is an important factor of central places. The average eigenvector centrality of 2010 migration is the lowest during 2005-2015, and it means few regions have high centralities. When comparing migration and travel networks, travel data is more effective than migration data in determining the central location considering spatial functions.

• 한국정보과학회논문지:시스템및이론
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• 제36권4호
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• pp.283-290
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• 2009

Rank/select 자료구조는 트리, 그래프, 문자열 인덱스 등의 다양한 자료구조를 간결하게 표현하는 기본 도구이다. Rank/select 자료구조는 주어진 문자열에 어느 위치까지 나타난 문자 개수를 세는 연산을 처리한다. 효율적인 rank/select 자료구조를 위해 이론적인 압축 방식들이 제안되었으나, 실제 구현에 있어 연산 시간 및 저장 공간의 효율을 보장할 수 없었다. 본 논문은 간단한 방법으로 이론적인 압축 크기를 보장하면서 연산 시간도 효율적인 rank/select 자료구조 구현 방법을 제시한다. 본 논문의 실험을 통해, 복잡한 인코딩 방법 없이도 이론적인 nH$_0$ + O(n) 비트 크기에 근접하면서 기존의 HSS 자료구조보다 빠른 rank/select 연산을 지원하는 구현 방법임을 보인다.