• 대한기계학회논문집B
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• 제29권12호
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• pp.1369-1376
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• 2005

Effective mixing gives strong advantageous impact on microfluidic applications since mixing is in general very slow process motivated by molecular diffusion transport only on the micro-scale. In this work, the mixing characteristics are analyzed in a Y-channel micromixer with obstacles. For the through analysis, our laboratory in-house unstructured grid CFD code is validated through solving a concentration transport in a uniform microchannel. The solutions well correspond to both exact solutions and those from MemCFD. Mixing in a Y-channel micromixer with obstacles is numerically investigated by the in-house code to search the optimal radius and layout of obstacles. From the simulations, the mixing efficiency appears to be proportional to the magnitude of the formation of lateral velocity component. It is also shown that the asymmetric layout and radius enlargement of obstacles greatly improves mixing efficiency.

• 품질경영학회지
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• 제5권2호
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• pp.29-38
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• 1977

The QC circle is a small group organized for accomplishing the company's purpose of improving constitutions of the enterprise, developing the capabilities of the mem-bers and improving human relations. The present study intends to investigate the current situations and problems of the QC circle and to develop most effective models for QC circle movement in Korea. For this purpose the author surveyed 93 QC circles and interviewed more than 20 QC circle members and managers. The author has concluded that it is necessary to: 1. establish the authority and duty of the QC divisions. 2. train the top and middle management, especially the indirect divisions manage-ment. 3. motivate the QC circle members for achieving their purpose.

• 대한임베디드공학회논문지
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• 제11권6호
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• pp.335-341
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• 2016

As information technology advances rapidly, various smart devices are becoming an essential element in our lives. Smart devices are providing services to users through applications up on the operating system. Operating systems have a variety of rules, such as scheduling applications and controlling hardwares. Among those rules, it is significant to protect private information in the information-oriented society. Therefore, isolation task, that makes certain memory space separated for each application, should highly be guaranteed. However, modern operating system offers the function to access the memory space from other applications for the sake of debugging. If this ability is misused, private information can be leaked or modified. Even though the access authority to memory is strictly managed, there exist cases found exploited. In this paper, we analyze the problems of the function provided in the Android environment that is the most popular and opened operating system. Also, we discuss how to avoid such kind of problems and verify with experiments.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2014년도 제26회 한글 및 한국어 정보처리 학술대회
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• pp.161-163
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• 2014

자연어 처리를 이용한 다양한 응용 시스템에서 지식베이스는 중요한 요소이다. 지식베이스의 대표적인 예로 YAGO와 디비피디아 등이 있다. YAGO는 고성능의 지식베이스지만 한국어를 지원하지 않는다는 문제점이 있다. 그리고 디비피디아는 한국어를 지원하지만 트리플의 속성이 세분화되어 있어서 사용이 어렵다. 본 논문에서는 YAGO와 디비피디아의 트리플을 매칭하여 디비피디아 트리플의 속성을 YAGO에서 사용하는 관계명으로 변환하고 MEM을 이용해 매칭되지 않은 트리플의 속성을 자동으로 분류하는 시스템을 제안한다. 제안한 방식으로 실험한 결과 F1-Measure 79.04%의 성능을 보였다.

• 대한수학회보
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• 제27권2호
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• pp.127-131
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• 1990

Let f:R.rarw.R be a continuous function on the real line R, and denote the n-th iterate of f by f$^{n}$ :f$^{1}$=f and f$^{n}$ =f.f$^{n-1}$ for n>1. A point x.mem.R is a periodic point of f of period k>0 if f$^{k}$ (x)=x but f$^{i}$ (x).neq.x for all 01, then it must also have a fixed point, by the intermediate Theorem. Also the question has an intriguing answer which was found by ths Russian mathematician Sharkovky [6] in 1964.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 춘계 총회 및 학술발표회
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• pp.61-62
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• 1994

In order to prepare polyion complex membranes useful for the separation of water-alcohol by pervaporation, k-carrageenan containing artionic sulfate groups in the backbone and good hydrophilicity was selected for the polyanion membrane material and poly{1,3-bis[4-butyl pyridinium] propane. bromide}, one of the polycations synthesized in our lab and containing cationic pyridinium groups., was used. The polyion complex membranes were prepared by the ion complex formation between kcarrageenan films and poly{1,3-bis[4-butyl pyridinium] propane. bromide}. On the formation process of polyion complex membranes, the way of potyion complex formation was carefully studied. In order to study the effect of the morphology on the permeation properties of the polyion complex membranes, which is one of the important factors affecting on the permeation properties of membranes but rarely studied, the microstructure behaviors of the polyion complex mem6ranes in methanol-water mixtures with different compositions Were also studied with x-ray diffractometry and polarizing microscopy.

• 전기의세계
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• 제41권11호
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• pp.8-15
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• 1992

요즘 자기 스스로 움직이면서 간단한 동작을 명령대로 수행하는 마이크로 머신을 만드는 꿈과같은 이야기를 현실에 한발 가까이 하는 연구가 활발히 진행되고 있다. 즉, IC칩을 제작하는 미세반도체 소자 제조공정으로 수십 내지는 수백미크론 크기의 기계구조물이나 모터, 액츄에이터를 실리콘 기판 위에 제작하는 것이 가능하게 되었다. 이러한 연구분야는 1980년대 중반부터 미국, 일본, 유럽등지에서 시작되었다. 이 연구분야를 IEEE에서는 MEMS(Micro Electro Mechanical Systems)라 부르며, 매년 2월 IEEE주최로 이에 관한 International conference가 열리고 있고, 이분야에 대한 Journal도 1992년부터 발행하고 있다. MEMS를 미국에서는 NSF(National Science Foundation)에서 일본에서는 통산성에서 지원하고 있으며 현재 재료, 제작기술, 소자(센서, 액츄에이터), 시스템, 응용, 마이크로 이공학등에 관한 연구가 진행되고 있다. 이 분양의 파급효과는 의공학이나 유전자공학 뿐만이 아니라 공학에도 매우 크리라 예상된다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.196-203
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• 2000

On the assumption that the voices of the cows are produced by the linear prediction filter, we characterized the cows' voices. The order of this filter is determined by examining the voices characteristics both in time and frequency domains. The proposed order of the linear prediction filter is 15 for modeling voice production of the cow. The combination of the two parameters of the fundamental frequency, the slope of the straight line regressed from the log-log spectra of the amplitude-envelope and the only one coefficient involved in the linear prediction filter can differentiate the two cows.

• 한국수정란이식학회지
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• 제16권1호
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• pp.61-68
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• 2001

Sperm competent for fertilization can become capacitated, bind to the zona pellucida (ZP) of an egg in a specific manner, and complete acrosomal exocytosis. Failure to carry out these functions results in infertility. Although the interactions between the ZP and the plasma mem-brane overlying the sperm acrosome have been considered important for sperm-egg recognition and signalling, recent results have prompted a reassessment of current paradigms concerning these interactions. In this review, we're going to discuss about the roles of the acrosomal matrix, the particulate component of the acrosomal contents, in fertilization. The general hypothesis is that acrosomal exocytosis leads to the exposure of acrosomal matrix proteins that become de-facto extracellular matrix (ECM) on the surface of the sperm head, and that the dynamic interactions of this newly-exposed sperm ECM with the egg ECM (the ZP) govern sperm-egg recognition and sperm penetration of the ZP Informations from these experiments may provide new ways to address the poor ZP binding of sperm from some human infertility patients and may offer new avenues for contraception through the disruption of purposeful sperm-ZP binding.

• 품질경영학회지
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• 제28권2호
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• pp.161-175
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• 2000

The problem of jointly determining the optimum process mem and screening limits for each market is considered in situations where there are several markets with different price/cost structures. Two inspection procedures are considered; an inspection based on the quality characteristic of interest, and an inspection based on a surrogate variable which is highly correlated with the quality characteristic. The quality characteristic is assumed to be a normal distribution with unknown mean and known variance. A Taguchi's quadratic loss function is utilized for developing the economic model for determining the optimum process mean and screening limits. A numerical example is given.