• 경영과학
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• 제16권2호
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• pp.137-147
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• 1999

This paper compares and evaluates the performances of the two types of mathematical programming models for solving the machine-part cell formation problem in group technology manufacturing : indirect formulation relying on surrogate measure such as similarity coefficient and direct formulation seeking to minimize the number of exceptional elements. New indirect formulation, called the generalized {{{{ { p}_{ } }}-median model. is proposed. Unlike existing {{{{ { p}_{ } }}-median formulations, proposed formulation includes the classical cell formation problem in which only one process plan exsits for each part as a special case. The proposed new formulation can also deal with the cell formation problem in which alternative process plans exist for a part. The indirect formulation is compared with a new direct formulation which needs much fewer extra variables and constraints than existing direct formulations. Some significant findings from comparative experiment are discussed.

• 충청수학회지
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• 제29권4호
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• pp.585-598
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• 2016

This paper shows that the solutions to the nonlinear perturbed differential system $$y^{\prime}=f(t,y)+{\int_{t_0}^{t}}g(s,y(s),T_1y(s))ds+h(t,y(t),T_2y(t))$$, have bounded properties. To show these properties, we impose conditions on the perturbed part ${\int_{t_0}^{t}}g(s,y(s),T_1y(s))ds,h(t,y(t),T_2y(t))$, and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of h-stability.

• The Korean Journal of Ecology
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• 제12권3호
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• pp.191-202
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• 1989

This study was carried out to investigate the relationship between soil mites(Acarina:Cryptostigmata) and vegetation in sampled area. From July 1984 to June 1985, samples were taken monthly from coniferous forests; a pinenut (Pinus koraiensis S. et Z.) forest (site C-1), a whitepine(Pinus strobus L.) forest (site C-2), a needle fir tree(Abies holophyla Max.) forest (site C-3), and three broad-leaved forests; site B-1, B-2, and B-3 in Cholanamdo province, southerm part of Korea. Vascular plants of 152 species belonging to 115 genera (53 families) were identified. The flora in the coniferous forests were more diverse than in the broad-leaved forest. Similarity coefficient to the flora was shown highly between the neighbouring sites. The oribatid species in the coniferous forests were more diverse than those in the broadleaved forests. The similarity index suggested that oribatid mites in those surveying sites could be divided into "coniferous forest type" and "broad-leaved forest type".d forest type".uot;.

• 복식
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• 제56권7호
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• pp.17-30
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• 2006

The objectives of this study are to research into the traditional costume succession in south and north korea, and to compare similarity and difference of kinds, names, drawing of Jegory. Conclusions are described as follows: 1. In sort of Jegory, south and north korea have same kind of Jegory according to traditional form. But in making method, south korea have pursued various style from traditional type to modern type, north korea have maintained just simple and practical basic style. 2. South and north korea have used same or similar names for the basic part of Jegory. But north korea has made new names for constructional needs, so many differences were shown in the name of details. 3. In drawing of Jegory, north korea has hold traditional method and then tried to seek for rational, scientific technique. Also, due to the influence of south korea that advanced in modern aesthetic, drawing of Jegory in north korea were changed to similar.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.181-186
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• 2005

In collaborative environment, it is necessary that the participants in collaboration should share the same understanding about the semantics of terms. For example, they should know that 'Part' and 'Item' are different word-expressions for the same meaning. In this paper, we consider sharing between CAD and PDM data. In order to handle such problems in information sharing, an information system needs to automatically recognize that the terms have the same semantics. Serving this purpose, the semantic mapping logic and the ontology based mapper system is described in this paper. In the semantic mapping logic topic, we introduce our logic that consists of four modules: Character Matching, Instance Reasoning, definition comparing and Similarity Checking. In the ontology based mapper, we introduce the system architecture and the mapping procedure.

• 정보관리학회지
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• 제24권1호
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• pp.103-120
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• 2007

노드는 문서를 구성하는 작은 크기의 의미 있는 정보 단위이다. 정보검색에 문서의 구조정보를 이용함과 더불어 문서보다 작은 검색단위에 대한 연구가 활발히 이루어지고 있다. 이 연구에서는 노드정보를 이용한 검색실험을 위해 벡터공간모델 검색기법을 사용하여 다양한 유사도 산출방식을 적용한 실험과 구조정보를 활용한 확장 실험을 수행하였다. 실험결과 문서의 유사도를 산출하는 방식에 따른 검색성능의 차이는 거의 나타나지 않았으며, 구조정보를 적용하는 확장 노드검색이 가장 좋은 성능을 나타냈다.

• 충청수학회지
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• 제30권3호
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• pp.291-304
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• 2017

This paper shows that the solutions to the perturbed differential system $$y^{\prime}=f(t,y)+{{\displaystyle\smashmargin{2}{\int\nolimits_{t_0}}^{t}}g(s,y(s),T_1y(s))ds+h(t,y(t),T_2y(t))$$, have bounded properties by imposing conditions on the perturbed part ${\int}_{t_0}^{t}g(s,y(s),T_1y(s))ds,h(t,y(t),T_2y(t))$, and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of h-stability.

• 통합자연과학논문집
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• 제9권4호
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• pp.241-248
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• 2016

Corticotropin-releasing factor receptors (CRFRs) activate the hypothalamic-pituitary-adrenal axis, which is an integral part of the fight or flight response to stress. Increase in CRH level is observed in Alzheimer's disease and major depression and hypoglycemia. Here, we report on the relevant physicochemical parameters required for the CRFR inhibitors. Comparative molecular similarity indices analysis (CoMSIA) was performed with the derivatives of 8-substituted-2-aryl-5-alkylaminoquinolinesas CRFR inhibitors. The best predictions were obtained for the best CoMSIA model with a $q^2$ of 0.576 with 6 components and $r^2$ of 0.977. The statistical parameters from the generated CoMSIA models indicated that the data are well fitted and have high predictive ability. CoMSIA contour maps could be useful in the designing of more potent and novel CRFR derivatives.

• International Journal of Fluid Machinery and Systems
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• 제10권3호
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• pp.197-208
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• 2017

When Francis turbines operate at partial load, residual swirl in the draft tube causes low-frequency pulsation of pressure and power output. Scale effects and system response may bias the prediction of prototype behavior based on laboratory tests, but could be overcome by means of a 1D analytical model. This paper deals with the two most important features of such a model, the compliance and the source of excitation. In a distributed-parameter version, compliance should be represented as an exponential function of local pressure. Lack of similarity due to different Froude number can thus be compensated. The normally unknown gas content in the vortex cavity has significant influence on the pulsation, and should therefore be measured and considered as a test parameter.

• 소성∙가공
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• 제11권5호
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• pp.430-438
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• 2002

This paper suggests the new technology to control metal flow in orther to change of the cold forging from conventional deep drawing forming. This technology can be summarized the complex forming, which consists of bulk forming and sheet forming, and multi-action forging, which be performed double action press. The proposed technology is applied to hub clutch model which is part of auto-transmission for automobile. The purpose of this study is to investigate the material flow behavior of hub clutch through control the relative velocity ratio and the stroke of mandrel and punch using the flow forming technique. First of all, the finite element simulations are applied to analyse optimal process conditions to prevent flow defect(necking defect etc.) from non-uniform metal flow, then the results are compared with the plasticine model material experiments. The punch load for real material is predict from similarity law. Finally, the model material experiment results are in good agreement with the FE simulation ones.