• Journal of Mechanical Science and Technology
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• 제16권11호
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• pp.1522-1539
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• 2002

In the present study, an explicit algebraic stress model is shown to be the exact tensor representation of algebraic stress model by directly solving a set of algebraic equations without resort to tensor representation theory. This repeals the constraints on the Reynolds stress, which are based on the principle of material frame indifference and positive semi-definiteness. An a priori test of the explicit algebraic stress model is carried out by using the DNS database for a fully developed channel flow at Rer = 135. It is confirmed that two-point correlation function between the velocity fluctuation and the Laplacians of the pressure-gradient i s anisotropic and asymmetric in the wall-normal direction. Thus, a novel composite algebraic Reynolds stress model is proposed and applied to the channel flow calculation, which incorporates non-local effect in the algebraic framework to predict near-wall behavior correctly.

• 아동학회지
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• 제22권2호
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• pp.315-327
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• 2001

This study investigated young children's spatial representation of geometrical relations based on their drawings of cube buildings. One hundred seventy-six children from 3 to 6 years of ages were selected from private kindergartens and day care centers. Their drawings were classified into 6 developmental levels: level 1 - drawings show only scribbles or several circles; level 2 - drawings show plane squares from a front view; level 3 - positional relations are included in the drawings; level 4 - separate-joint relations or the general outline of a cube building are shown; level 5 - rotated drawing and an additional square for hidden faces are attempted to represent the lateral view; level 6 - parallel lines are drawn to represent 3-dimensional structures. Three-to four-year-olds were between levels 1 and 2; four-to six-year olds were between levels 3 and 4; and children over six years old were between levels 3 and 5.

• 한국수자원학회논문집
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• 제33권S1호
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• pp.28-36
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• 2000

A TIN, Triagulated Irregular Network, based topographic modeling method and a distributed rainfall-runoff model using the topographic representation is presented. In the TIN based topographic representation, a watershed basin is modeled as a set of contiguous non-overlapping triagular facets : the watershed basin is subdivided according to streamlines to deal with water movement one-dimensionally ; and each partitioned catchment is approximated to a slope element having a quasi-three-dimensional shape by using cubic spline functions. On an approximated slope element, water movement is represented by combined surface-subsurface kinematic wave equations considering a change of slope gradient and slope width. By using the distributed rainfall-runoff model, the effects of spatial variability of soil properties on runoff response are examined.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.170-177
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• 2014

This paper presents a new method of classification of the induction machine faults using Time Frequency Representation, Particle Swarm Optimization and artificial neural network. The essence of the feature extraction is to project from faulty machine to a low size signal time-frequency representation (TFR), which is deliberately designed for maximizing the separability between classes, a distinct TFR is designed for each class. The feature vectors size is optimized using Particle Swarm Optimization method (PSO). The classifier is designed using an artificial neural network. This method allows an accurate classification independently of load level. The introduction of the PSO in the classification procedure has given good results using the reduced size of the feature vectors obtained by the optimization process. These results are validated on a 5.5-kW induction motor test bench.

• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.263-268
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• 2008

An improved linear matrix inequality (LMI) representation of delay-independent $H_2$ performance analysis is introduced for linear delay systems with delays of any size. Based on this representation we propose a new $H_2$ memoryless state feedback design. By introducing a new matrix variable, the new LMI formulation enables us to parameterize memoryles s controllers without involving the Lyapunov variables in the formulations. By using a parameter-dependent Lyapunov function, this new representation proposed here provides us the results with less conservatism.

• 대한산업공학회지
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• 제22권3호
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• pp.427-440
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• 1996

Constraint networks are a major approach to knowledge representation in Concurrent Engineering (CE) systems. The networks model various factors in CE as constraints linked by shared variables. Many systems have been developed to assist constraint network processing. While these systems can be useful, their underlying assumption that a solution must simultaneously satisfy all the constraints is often unrealistic and hard to achieve. Proposed in this paper is a hierarchical representation of constraint networks using priorities, namely Prioritized Constraint Network (PCN). A mechanism to propagate priorities is developed, and a new satisfiability definition taking into account the priorities is described. Strength of constraint supporters can be derived from the propagated priorities. Several properties useful for investigating PCN's and finding effective solving strategies ore developed.

• 충청수학회지
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• 제23권3호
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• pp.495-510
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• 2010

An Einstein's connection which takes the form (2.23) is called a $^*g$-ME-connection and the corresponding vector is called a $^*g$-ME-vector. The $^*g$-ME-manifold is a generalized n-dimensional Riemannian manifold $X_n$ on which the differential geometric structure is imposed by the unified field tensor $^*g^{{\lambda}{\nu}}$, satisfying certain conditions, through the $^*g$-ME-connection and we denote it by $^*g-MEX_n$. The purpose of this paper is to derive a general representation and a special representation of the $^*g$-ME-vector in $^*g-MEX_n$.

• 인지과학
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• 제14권2호
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• pp.37-46
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• 2003

성별 고정관념은 대인 집단에 관한 표상이며 암묵적 수준에서 자동적으로 처리된다고 알려졌다. 이 연구는 고정관념의 속성 전형성과 집단 일치성 변인의 효과가 암묵적 점화과제에 반영되는지를 관찰하고자 하였다. 실험 1에서는 성별 고정관념의 성별 속성을 전형성과 선호도 변인을 조작하여 점화 자극으로 제시한 다음 성별 이름에 대한 명명시간을 측정하였다. 전형성 변인의 효과만 관찰되었고, 그 효과는 여자에서 나타났다. 반면에 집단 일치성 효과는 관찰되지 않았다. 실험 2에서는 고정관념의 속성간 조건으로 전형성 변인의 점화효과를 체계적으로 관찰하고자 하였다. 성별 범주의 주효과만 나타났고, 여성 속성이 남성 속성에 비해서 점화효과가 크게 관찰되었다. 전형성 변인의 주효과와 집단 일치성 효과는 관찰되지 않았다. 두 실험의 결과, 성별 고정관념의 속성 전형성은 암묵적인 수준에서 미약하지만 표상에 영향을 미칠 가능성을 확인하였다. 반면에 성별의 집단 일치성 효과는 표상에 영향을 미치지 않았다. 이는 성별 속성이 미약하지만 전형성에 따라 단계적으로 표상되었을 가능성과 성별의 표상이 참가자 성에 따라 비대칭적으로 표상되었을 가능성을 시사하는 것이다.

• 한국정보전자통신기술학회논문지
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• 제2권1호
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• pp.37-42
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• 2009

디지털 신호 처리 분야에서 디지털 필터는 필수불가결한 요소이다. 디지털 필터는 이진수의 곱셈 및 덧셈을 기본으로 하는 것으로 많은 연산량을 필요로 한다. 디지털 필터 내의 곱셈기는 VLSI 기술을 이용한 디지털 필터의 설계에 있어 반도체 칩 내부의 넓은 영역을 차지하고 전력의 대부분을 소비하며, 필터의 critical path를 결정하여 필터의 성능을 결정하는 중요한 요소로서 작용 한다. 본 연구에서는 특히 디지털 필터의 복잡성(complexity)를 해소하고 critical path를 줄여 필터의 연산속도를 증가시키기 위한 방법으로 2의 보수로서 표현되는 이진수를 CSD(canonical signed digit)와 MSD(minimal signed digit)로 동시에 변환하여 표현하는 방법을 제안하였다. 제안된 방법은 VHDL로 구현하고 임의의 필터에 적용하여 필터의 critical path가 감소하는 것을 보였다.

• 한국의류산업학회지
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• 제14권6호
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• pp.906-917
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• 2012

The purpose of this study is to examine the characteristics of expression and their effects of New painting in fashion illustration since 1990s. This study is focused on searching for the development in expressional techniques of the fashion illustration on the basis of various techniques of New painting. New painting as a trend of new expressionism in America was developed in opposition to the minimalism in the 1980s when the discussion of the post-modernism was most widely. The artists of New painting attempted to resurrect figure through the representation of figure and concrete image, rich in color and strong in image. They also expressed the realistic scene of life with the various kind of medium, materials and styles and appropriation of image from mass media and popular culture. The representation of fashion figure and image through the various kind of painting medium, techniques and styles can express the realistic and sensitive image and increase the communication ability in fashion illustration. It could also deliver the fashion message more clearly through the appropriation of image. These findings indicate that fashion illustrations accept variety by interacting with fine arts and expand the scope of expression.