• Journal of Mechanical Science and Technology
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• 제18권9호
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• pp.1549-1558
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• 2004

This study is concerned with the general solution of the field intensity factors and energy release rate for a Griffith crack in a piezoelectric ceramic of finite radius under combined anti-plane mechanical and in-plane electrical loading. Both electrically continuous and impermeable crack surface conditions are considered. Employing Mellin transforms and Fourier series, the problem is reduced to dual integral forms. The solution to the resulting expressions is expressed in terms of Fredholm integral equation of the second kind. The solutions are provided to study the influence of the crack length, the crack surface boundary conditions on the intensity factors and the energy release rate.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.410-413
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• 2005

There are technical requirements to manufacture large size functional parts with not only simple geometries like a flat or spherical surface but also sculptured geometries. In addition, the required machining accuracy for these parts is becoming more severe day-by-day. In general, the forms of machined parts are determined by relative position between the workpiece and the tool during cutting. To improve machining accuracy, the relative position error should be maintained within the required accuracy. This study deals with estimation and calibration of depth of cut using AE signal in micro-machining.

• 한국통신학회논문지
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• 제16권4호
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• pp.358-381
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• 1991

본 논문에서는 모니터 개념에 입각한 IPC 메커니즘을 사용하는 원격 데이터 액세스 인터페이스 모델을 구축하였다. 네트워크 환경에서 작동하는 분삭 프로세스들에 대하여 유연성 있는 통신 제어를 구현하기 위한 일반성 있는 IPC 메커니즘이 모델의 프레임워크 확립을 위한 기반으로 개발되었다. 위의 IPC 메커니즘을 사용하여 응용 프로세스들에게 원격 데이터 액세스 기능을 부여할 수 있도록 인터페이스 모델과 동기 메커니즘이 기술되었다.

• Journal of Information Processing Systems
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• 제14권2호
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• pp.539-551
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• 2018

Images are unavoidably contaminated with different types of noise during the processes of image acquisition and transmission. The main forms of noise are impulse noise (is also called salt and pepper noise) and Gaussian noise. In this paper, an effective method of removing mixed noise from images is proposed. In general, different types of denoising methods are designed for different types of noise; for example, the median filter displays good performance in removing impulse noise, and the wavelet denoising algorithm displays good performance in removing Gaussian noise. However, images are affected by more than one type of noise in many cases. To reduce both impulse noise and Gaussian noise, this paper proposes a denoising method that combines adaptive median filtering (AMF) based on impulse noise detection with the wavelet threshold denoising method based on a Gaussian mixture model (GMM). The simulation results show that the proposed method achieves much better denoising performance than the median filter or the wavelet denoising method for images contaminated with mixed noise.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.139-145
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• 2002

Recently, power-electronics equipments or machine that microprocessor is included and computers have been installed continuously in industrial process or region of electronics customer. So concern for power quality, especially sags has been increased. Because those equipments are very sensitive to sags. The sag is phenomenon that magnitude of load voltage temporarily decreases because of power system fault. If a certain equipment in industrial process have any trouble result from sag, it can cause utility to be charged for enormous economics loss. Therefore it need to analyze the characteristic of sag and then mitigation method for sags in distribution system in odor to increase reliability. This paper gives an overview of sags characteristic due to short circuit fault in distribution system and after a general discussion of the various forms mitigation, gives a sags mitigation method with concentrating on changing the distribution system like spot network, on-site generation.

• Journal of Advanced Marine Engineering and Technology
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• 제31권7호
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• pp.863-871
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• 2007

This paper proposes a methodology to estimate the system coefficients for the infinite impulse response(IIR) digital filters using real code GA. In the traditional real coded GA, it adapts the general genetic operations, whereas in this paper the proposed real coded GA applies improved genetic operations in order to search the optimal solution in given problems. Each of unknown IIR digital coefficients collected as forms of a chromosome. Two illustrative examples including the band pass and band stop IIR digital filters are demonstrated to verify the proposed method.

• 전기학회논문지
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• 제58권3호
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• pp.614-620
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• 2009

The force distribution in multi-legged robots is a constrained, optimization problem. The solution to the problem is the set points of the leg contact forces for a particular system task. In this paper, an efficient and general formulation of the force distribution problem is developed using linear programming. The considered walking robot is a quadruped robot with a locked-joint failure, i.e., a joint of the failed leg is locked at a known place. For overcoming the drawback of marginal stability in fault-tolerant gaits, we define safety margin on friction constraints as the objective function to be maximized. Dynamic features of locked-joint failure are represented by equality and inequality constraints of linear programming. Unlike the former study, our result can be applied to various forms of walking such as crab and turning gaits. Simulation results show the validity of the proposed scheme.

• 한국실내디자인학회논문집
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• 제14권5호
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• pp.193-204
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• 2005

Design took a radical turn in the 1980's, deconstructing the rigid ideology of the Modernism, often with great humor. Contemporary representable Avant-garde designers, Philippe Starck and Ron Arad brazenly borrowed from the 'historical elements' of previous styles and created bio-morphic forms with whimsical names of furniture. This study is proposed to understand the diversity of contemporary design, by comparing these two furniture designers. It also covers the common factors in contemporary furniture design, and analyzes their individual differences and similarities in design. It helps to plan the foundation of design methods for 21C, and predict and respond to the future as a reference point. Philippe Starck links Romantic Rationalism within Minimal style and Ron Arad links Deconstructivism within High-tech style but both of them pursue of Organic concept design in their furniture through the concept of humanism. They are able to establish a base of contemporary furniture design by adapting new conceptual form, and design process for the general public.

• 한국컴퓨터산업학회논문지
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• 제4권4호
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• pp.661-670
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• 2003

최근에 유비쿼터스 기술이 바뀌어 가고 있다. 유비쿼터스의 비전이 데스크탑 인터페이스와 정보 환경자체를 투명하게 변화시켜 주고 있다 유비쿼터스 연구는 컴퓨터 분야에서 많은 이슈를 던져주고 있고, 그러나 적용되는 사례에 있어서 다 성공적인 것 많은 아니다. 성공하기 위해서는 소프트웨어 엔지니어링과 연구와 결부 시켜야 한다. 그리고 많은 그와 관련된 응용 부분이 개발되어져야만 유비쿼터스 컴퓨팅안에 연구가 성공적일 수 있다. 우리는 이 문제에 대하여 살펴보았고, 이 논문에서는 정보기술 연구에 대한 방향을 검토, 비교, 제시하였다.

• 대한수학회보
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• 제34권2호
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• pp.273-285
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• 1997

The aim of this paper is to present theorems on the exitence of zeros for mappings defined on convex subsets of topological vector spaces with values in a vector space. In addition to natural assumptions of continuity, convexity, and compactness, the mappings are subject to some geometric conditions. In the first theorem, the mapping satisfies a "Darboux-type" property expressed in terms of an auxiliary numerical function. Typically, this functions is, in this case, related to an order structure on the target space. We derive an existence theorem for "obtuse" quasiconvex mappings with values in an ordered vector space. In the second theorem, we prove the existence of a "common zero" for an arbitrary (not necessarily countable) family of mappings satisfying a general "inwardness" condition againg expressed in terms of numerical functions (these numerical functions could be duality pairings (more generally, bilinear forms)). Our inwardness condition encompasses classical inwardness conditions of Leray-Schauder, Altman, or Bergman-Halpern types.