• 한국자동차공학회논문집
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• 제16권6호
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• pp.88-96
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• 2008

Currently, due to the serious world-wide air pollution by substances emitted from vehicles, emission control is enforced more firmly and it is expected that the regulation requirements for emission will become more severe. A new concept combustion technology that can reduce the NOx and PM in relation to combustion is urgently required. This study used a split injection method at a 4 cylinder common-rail direct injection diesel engine in order to apply the partially premixed charge compression ignition combustion method without significantly altering engine specifications And it is investigated that the effects of the injection ratio and SCV(swirl control valve) to emission characteristics. From these tests, soot(g) and NOx(g) emission could be reduced to 40% and 92% compared to base engine performance at specified engine driving conditions(6 points with weight factors) according to application of split injection and SCV(swirl control valve).

• 한국발생생물학회지:발생과생식
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• 제23권2호
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• pp.139-148
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• 2019

Rising of water temperature due to global warming is a great concern to aquaculturists and fishery biologists. Hence, the present study aimed to investigate the effects of high water temperature on juvenile red spotted grouper, Epinephelus akaara based on the evaluation of stress responses in blood. E. akaara juveniles were exposed to different thermal conditions ($25^{\circ}C$, $28^{\circ}C$, $31^{\circ}C$, and $34^{\circ}C$) for 6 weeks following 2 weeks of acclimation at $25^{\circ}C$. Blood cell morphology and number were examined at three sampling points (2, 7, and 42 days) from a total of 180 fish. Major erythrocytic cellular abnormalities (ECA) observed in blood smears of thermally stressed groups ($31^{\circ}C$ and $34^{\circ}C$) after 6 weeks were echinocytes, teardrop-like cells, swollen cells and vacuolated cells. Both red and white blood cell number (RBC and WBC) were significantly (p<0.05) elevated in $31^{\circ}C$ and $34^{\circ}C$ group after 6 weeks thermal exposure. Differential leucocytes number showed significant increases in neutrophil (N) and decreases in lymphocytes (L) in the highest temperature ($34^{\circ}C$). Different N:L ratio was observed at different thermal conditions which can be used as a reliable alternative to measure stress response. Taken together, these results suggest that higher temperature ($31^{\circ}C$ and $34^{\circ}C$) can interfere the immune system of red spotted grouper by altering the blood cell morphology and number.

• Steel and Composite Structures
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• 제37권6호
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• pp.663-678
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• 2020

This paper proposes a novel topology optimization method generating multiple materials for external linear plane crack structures based on the combination of IsoGeometric Analysis (IGA) and eXtended Finite Element Method (X-FEM). A so-called eXtended IsoGeometric Analysis (X-IGA) is derived for a mechanical description of a strong discontinuity state's continuous boundaries through the inherited special properties of X-FEM. In X-IGA, control points and patches play the same role with nodes and sub-domains in the finite element method. While being similar to X-FEM, enrichment functions are added to finite element approximation without any mesh generation. The geometry of structures based on basic functions of Non-Uniform Rational B-Splines (NURBS) provides accurate and reliable results. Moreover, the basis function to define the geometry becomes a systematic p-refinement to control the field approximation order without altering the geometry or its parameterization. The accuracy of analytical solutions of X-IGA for the crack problem, which is superior to a conventional X-FEM, guarantees the reliability of the optimal multi-material retrofitting against external cracks through using topology optimization. Topology optimization is applied to the minimal compliance design of two-dimensional plane linear cracked structures retrofitted by multiple distinct materials to prevent the propagation of the present crack pattern. The alternating active-phase algorithm with optimality criteria-based algorithms is employed to update design variables of element densities. Numerical results under different lengths, positions, and angles of given cracks verify the proposed method's efficiency and feasibility in using X-IGA compared to a conventional X-FEM.

• 한국해안·해양공학회논문집
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• 제33권4호
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• pp.160-167
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• 2021

단층파괴에 의한 해저지형변화는 공간적으로 시간차를 가진다. 특정 지점에서 파괴가 발생하면 이웃지점으로 단층파괴가 전파하면서 시간차에 따른 단층파괴가 발생하며, 단층파괴시 연직방향으로 상승하면서 지진해일을 야기한다. 해저 지형의 상승속도는 지진해일 초기파형에 영향을 주며 결과적으로 지진해일의 도달시간 및 크기에 영향을 준다. 본 연구에서는 단층파괴에 의한 해저 지형의 수평적 및 수직적 변화를 능동적 및 동적으로 고려하여 지진해일의 생성 및 전파를 모의할 수 있는 수치모형을 개발하였다. 모델의 검증을 위하여 2011년 동일본대지진에 대해 적용하였으며 기존의 수동적 및 정적 모형에 비해 정확성이 개선되는 것을 확인하였다.

• 미술이론과 현장
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• 제9호
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• pp.33-57
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• 2010

Focused on the performance of interactivity in the appreciation of media art, this study is associated with the continually changed art texts and a participator's physical reactions to savor the art. Digital works of art emphasizing interactivity usually decentralize and disperse the responsibility and the central role for creating and producing the art works. Proper procedure of the work is generated by actions such as clicking the mouse, controlling the joy stick or actual movement of anticipators' bodies. The art works are influenced by participators' interactivity, which makes the leading roles and the responsibility for creating art scattered and divided. These features are similar with those of the 'Rhizome' which Gilles Deleuze(1925~1995) and Felix Guattari(1930~1992) have discussed. In their argument, 'Rhizome' is an interval or being 'between', which keeps changing. 'Rhizome' is a state in which the individual and the work of art never reach the conclusion, only a phenomenon of eternally altering. Like 'Rhizome', this sort of art work has the decentralized system, opens for several directions, and activates the system which is changeable as linked items increased or decreased. These works stimulate the individual to perform and act while appreciating the art piece. In terms of processing and preceeding, interactivity is the important equipment and catalyzer. Through these procedures, the pieces can be the 'floating work of art' combined and condensed with the whole participators' reactions. The 'floating work of art' is neither the expression of an individual nor that of one particular group. Multidimensional influence of the web is the web which is constantly reorganizing and producing in its connective state. This connective state is activated by interactivity. The Rhizomatic system embodies the floating work of art process. Due to each individual perceiving art in individualistic terms, there is no dominating powers or central points. I regard this art works possessing above traits as the work of art with Rhizomatic system. The work of art with the Rhizomatic system is embodied through interactivity and because physical action activates the process of appreciation, a participator can actually experience and practice the philosophy. Ultimately the Rhizomatic speculation occurs during the interactivity of appreciating the Rhizomatic art pieces. The Rhizomatic system penetrates into the intuitive area beyond our recognition and thoughts, as we are engaged in the connective process. With the methods and manners of interactive art, we can possibly reconsider the system as a tool in which the participator is directly able to link experience and theory to the philosophies of Deleuze and Guattari.

• Spatial Information Research
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• 제17권2호
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• pp.201-212
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• 2009

1980년대 후반 GIS분석 기법이 소개되면서 GIS를 활용한 토지이용에 관한 연구가 다양한 측면에서 진행되었으며, 2003년 이후에는 국토의 난개발 방지를 위해 환경 친화적인 녹색성장 측면에서의 국토관리를 계획하고자 토지적성평가제도가 도입되었다. 특히 용도지역의 지정 및 변경, 도시계획시설 설치 및 정비 등의 계획을 입안하기 위해 지형분석, 중첩분석, 거리분석 등 다양한 GIS분석 기법을 기반으로 한 토지적성평가 평가체계II가 도입되었다. 그러나 기초자료의 부정확, 평가지표상의 문제, 지역실정에 부합되지 않는 임계치, 평가체계간 평가결과 상충 등 많은 문제점들이 지적되었으며, 평가기준에 적합하지 않더라도 지표별 점수분포를 20점부터 적용하고 있어 개발위주의 평가결과를 제공하고 있다. 이에 본 연구에서는 현행 지침에서 지표별 점수를 20점부터 100점까지 제시하고 있는 점수분포 체계를 0점에서부터 100점까지 변경함으로써 적성값과 적성등급의 변화를 살펴보았다. 그 결과, 일부 필지에 대해서 등급변화가 나타났으며, 적성값의 경우 87%에 해당되는 필지들 의 값이 최소 1점에서 최대 70점까지 하락하는 변화를 보였다. 이는 평가체계II의 점수분포 체계의 변화가 적성등급과 적성값에 많은 영향을 미치게 되는 동시에 개발과 보전의 양면성을 모두 고려하였다는 측면에서 그리고 실증적 분석을 하였다는데 그 의의가 있다.