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        검색결과 5

        1.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The structural analysis module is an essential part of any integrated structural system. Diverse integrated systems today require, from the analysis module, efficient real-time responses to real-time input such as earthquake signals, extreme weather-related forces, and man-made accidents. An integrated system may also be for the entire life span of a civil structure conceived during the initial conception, developed throughout various design stages, effectively used in construction, and utilized during usage and maintenance. All these integrated systems’ essential part is the structural analysis module, which must be automated and computationally efficient so that responses may be almost immediate. The finite element method is often used for structural analysis, and for automation, many effective finite element meshes must be automatically generated for a given analysis. A computationally efficient finite element mesh generation scheme based on the r-h method of mesh refinement using strain deviations from the values at the Gauss points as error estimates from the previous mesh is described. Shape factors are used to sort out overly distorted elements. A standard cantilever beam analyzed by four-node plane stress elements is used as an example to show the effectiveness of the automated algorithm for a time-domain dynamic analysis. Although recent developments in computer hardware and software have made many new applications in integrated structural systems possible, structural analysis still needs to be executed efficiently in real-time. The algorithm applies to diverse integrated systems, including nonlinear analyses and general dynamic problems in earthquake engineering.
        4,000원
        2.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        유한요소법은 구조해석법으로 가장 많이 사용되는 방법으로 자리잡고 있으며, 근래에는 다소 복잡한 동적 및 비선형 문제에도 사용이 일반화되고 있다. 이러한 거동 예측이 어려운 구조해석에도 구조물을 적절한 유한요소와 요소망으로 표현하면 신뢰있는 해석 결과를 얻을 수 있다. 구조물의 동적 또는 비선형 거동에는 예상하지 않은 부분에서 큰 변형이 일어날 수 있으며, 유한요소해석 과정에서 같은 요소망을 계속 사용하면 요소의 모양이 신뢰 범위 밖으로 변형될 수 있으므로 요소망 역시 동적으로 적응할 필요가 있다. 또한, 유한요소 프로그램의 사용자 요구 사항 중 하나가 실시간으로 빠르게 진행되는 것이므로 연산면에서 효율적이어야 한다. 본 연구는 시간영역 동적해석에서 전 단계 해석 결과를 사용하여 계산된 대표 변형률 값을 오차 평가에 사용하여 절점 이동인 r-법과 요소 분할인 h-법의 조합으로 요소 세분화를 진행하여 동적으로 적응하는 요소망 형성 과정을 기술한다. 해석 중 과대하게 변형되는 요소는 모양계수 개념으로 방지한다. 간단한 프레임의 동적 유한 요소해석을 예제로 정확성과 연산 효율성을 보여준다. 본 연구에서 제시하는 적응적 유한요소망 형성 전략은 복잡한 동적 및 비선형 해석에 일반적으로 적용될 수 있다.
        4,000원
        3.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        MoSi-TiC composite powders were fabricated by in-situ reaction through mechanical alloying. Also the monolithic MoSi as well as TiC were synthesiced by mechanical alloying for comparison. An abrupt increase of vial surface temperature was detected due to a sudden reaction between elemental powders during milling. The reaction time for synthesis of composite powders decreased with increasing the content of (Ti+C) powder. It was found that a significant decrease of Ti grain size was observed with increasing the milling time. And the synthesis reaction of MoSi-TiC composite powders were largely dependent on the reaction between Ti and C powders.
        4,000원
        4.
        2005.03 KCI 등재 서비스 종료(열람 제한)
        Pureundeul farming corporation(PFC) is an exemplary body of all producer organizations for environmentally friendly agriculture(EFA) in Korea. It is located at Asan in Chungnam and has 301 farmers. They attained more than 10 billion wons as a sale in 2004. And The direct marketing channel of the EFA products is the second logistics center(Asan)→the first logistics center(Gwangju Gyunggi) → local hansalim shops → consumers. It is needed to construct the system of the direct marketing as follows : First, it needs to construct the direct marketing system within the region for EFA products of Asan. Second, the direct shop and suppling area should be enlarged as a way to promote sales with the demand increase of EFA products. Third, an aggressive promotion campaign is be needed for increasing motivation of consumption and understanding of EFA products.
        5.
        2005.03 KCI 등재 서비스 종료(열람 제한)
        This study was focused on the system of regional resource circulation(RRC) of Asan-Si as a case region. So 301 farmers(members of producer organization) who are managing environmental-friendly agriculture(EFA) are surveyed. The RRC system is focused on establishing the system of regional complex farming connected with the seedling farming and the livestock. The main results surveyed are as follows : First, total cultivated acreage is 574ha. Second, the total quantity of by-products of rices, beans, wheats is 983M/T. Third, the total quantity of nutrient requirement for seedling farming is 85,335.6kg This research shows how to develop the RRC system for EFA. The development model and strategies are as follows : The first model for the system of regional resource circulation can be called the scenario of the best output for the system of environmentally friendly resource circulation. It is considered to estimate the appropriate number of heads of Korean cattle and hen which can be bred simultaneously. And the second model can be called the scenario of the regional allotment for the appropriate number of heads of those. It is considered to estimate the appropriate number of heads of those which can be alloted by the individual farm or area.