• 한국산업보건학회지
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• 제20권3호
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• pp.203-215
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• 2010

This study is an overview of toxicities and measurement techniques of ultrafine particles (UFPs), and their exposure controls. UFPs are ubiquitous in many working situations. Exposure to UFPs is possibly causing adverse health symptoms including cardio-respiratory disease to humans. In order to measure exposure levels of airborne UFPs, there are current available measurement guidelines, instruments and other techniques (i.e. contour mapping, control banding). However, these risk assessment techniques including measurement techniques, controls and guidelines are dependent on background levels, metrics (e.g. size, mass, number, surface area, composition), environmental conditions and controls. There are no standardized measurement methods available and no generic and specific occupational exposure standards for UFPs. It is thought that there needs to be more effort to develop Regulations and Exposure Standards for generic UFPs should be based on more exposure data, health surveys, toxicological data and epidemiological data. A carefully considered hierarchy of controls can also reduce the maximum amount of airborne UFPs being emitted from diverse sources in industries.

• 대한산업공학회지
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• 제42권5호
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• pp.314-326
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• 2016

The purpose of variable selection techniques is to select a subset of relevant variables for a particular learning algorithm in order to improve the accuracy of prediction model and improve the efficiency of the model. We conduct an empirical analysis to evaluate and compare seven well-known variable selection techniques for multiple linear regression model, which is one of the most commonly used regression model in practice. The variable selection techniques we apply are forward selection, backward elimination, stepwise selection, genetic algorithm (GA), ridge regression, lasso (Least Absolute Shrinkage and Selection Operator) and elastic net. Based on the experiment with 49 regression data sets, it is found that GA resulted in the lowest error rates while lasso most significantly reduces the number of variables. In terms of computational efficiency, forward/backward elimination and lasso requires less time than the other techniques.

• 한국컴퓨터정보학회지
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• 제8권2호
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• pp.67-74
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• 2001

최근에 이용 가능한 데이터의 양이 폭발적으로 증가하고 있다 따라서 이들 데이터로부터 유용한 지식을 발견하는 자동화된 기법이 주목을 받고 있다. 데이터 마이닝이란 지식 발견의 중요한 단계로서, 데이터로부터 유용한 패턴을 발견하는 방법이다. 본 논문에서는 데이터 마이닝 기법을 조사한다 이러한 조사과정을 통하여 실세계에서 보다 효율적으로 적용 가능한 데이터 마이닝 기법을 찾아내고. 이들 기법에 대한 적절한 응용 영역과 앞으로의 연구방향을 제시한다.

• 한국가시화정보학회지
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• 제1권2호
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• pp.3-12
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• 2003

This paper describes the general aspects of various visualization techniques employed for marine engineering research including classical naval architecture, ocean engineering and other related topics. Visualization techniques performed mostly by authors' were introduced here, which range from old fashioned methods such as paint and tuft tests to the newly emerging PIV technique and Sonar in broad sense. Brief explanation of each technique was made for the instruction purposes. It is strongly recommended that the interdisciplinary project with experts in other research areas is necessary in order to develop more advanced and profitable techniques.

• 한국주거학회논문집
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• 제13권6호
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• pp.121-131
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• 2002

The rebuilding method for old apartment housing blocks has merits of providing new buildings and larger private living spaces. However, it causes many serious urban problems, such as shortage of infrastructure capacity, traffic congestion, reduction of building life, and deterioration of open space quality. Nowadays, remodeling is accepted as a way of overcoming such negative effects of the rebuilding method. This study focuses on the various techniques of remodeling. The results of this research are as follows; First, old apartment blocks provide poor level of service in general, so they have problems of bad accessibility, deterioration of facilities, and degraded landscape. In many cases, there is a hindrance from walking freely and security problem due to illegal privatization of public spaces. Second, various remodeling techniques are required to meet residents' different needs. The residents of apartment housing value private space above public space, and show low level of willingness to pay cost for remodeling. Third, based on these findings, some remodeling techniques are suggested - integration of a space to another, expansion of spaces, connection of spaces, reuses of roofs and walls, relocation and renovation of paths between buildings, and so on.

• 정보관리학회지
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• 제16권4호
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• pp.53-74
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• 1999

본 논문에서는 효율적인 암묵적 지식을 표현하기위한 도구로써 개념매핑기법에 대해 기술을 하고 있다. 개념매핑기법은 비형식적인 것에서부터 형식적인기법까지 다양하다. 형식적개념매핑은 사용이 용이하지만 컴퓨터 처리능력이 없다. 반면에 비형식적 개념매핑은 추론능력은 있으나 사용이 어렵다는 단점이 있다. 따라서 미래의 지식매핑시스템은 형식적ㆍ비형식적 개념기법의 장점을 모두 고려해야 할 것으로 보인다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.919-920
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• 2008

In this paper, we present early processing techniques for visual inspection of metallic parts. Since metallic surfaces give rise to specular reflections, it is difficult to extract object boundaries using elementary segmentation techniques such as edge detection or binary thresholding. In this paper, we present two techniques for finding object boundaries on micro bit images. First, we explain a technique for detecting blade boundaries using a directional correlation mask. Second, a line and angle extraction technique based on Harris corner detector and Hough transform is described. These techniques have been effective for detecting blade boundaries, and a number of experimental results are presented using real images.

• Structural Monitoring and Maintenance
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• 제1권2호
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• pp.197-211
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• 2014

An investigation of tunnel linings is performed at two tunnels in the US using complimentary noncontact techniques: air-coupled ground penetrating radar (GPR), and a vehicle-mounted scanning system (SPACETEC) that combines laser, visual, and infrared thermography scanning methods. This paper shows that a combination of such techniques can maximize inspection coverage in a comprehensive and efficient manner. Since ground-truth is typically not available in public tunnel field evaluations, the noncontact techniques used are compared with two reliable in-depth contact nondestructive testing methods: ground-coupled GPR and ultrasonic tomography. The noncontact techniques are used to identify and locate the reinforcement mesh, structural steel ribs, internal layer interfaces, shallow delamination, and tile debonding. It is shown that this combination of methods can be used synergistically to provide tunnel owners with a comprehensive and efficient approach for monitoring tunnel lining conditions.

• 한국시스템다이내믹스연구
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• 제5권1호
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• pp.35-47
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• 2004

Analyzers adopt a variety of techniques in analyzing public policy. Based on the results of exploration, they explain problems and suggest prescriptions such as policy alternatives. By doing so, however, they have different degree of confidence in their own results according to what techniques they adopt. This study explores whether system dynamics apporach gives analyzers more confidence on their own simulation results than other approaches do. This study designed an experiment. Three research teams are organized. Each of them applies different analytic techniques on the same policy issue, i.e., introduction of transportation tax. It flnds that researchers using S,D. simulation technique are most confident on what they predict, while researchers adopting survey techniques show moderate degree of confidence on their results. Researchers using regression are least confident.

• 정보관리연구
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• 제27권1호
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• pp.40-65
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• 1996

본고에서는 VOCED 데이터베이스의 정보검색기법을 살펴보았다. VOCED 데이터베이스를 직업 교육 및 훈련, 그러고 성인교육분야와 관련된 국제적인 정보를 수록하고 있다. VOCED는 CDS/ISIS 소프트웨어를 통해 구축되었으며, 레코드는 APSDEP 시소러스를 사용하여 색인되었다. VOCED 데이터베이스의 정보검색시에는 여러가지 검색기법들을 사용할 수 있다. 다수용어, 구문, 불리안 논리, 용어절단, 제한탐색 및 인접탐색기법 등을 통해 원하는 정보에 신속히 접근할 수 있다.