• Nuclear Engineering and Technology
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• v.41 no.7
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• pp.953-968
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• 2009

It is important to accurately predict the temperature and density distributions in large stratified enclosures both for design optimization and accident analysis. Current reactor system analysis codes only provide lumped-volume based models that can give very approximate results. Previous scaling analysis has shown that stratified mixing processes in large stably stratified enclosures can be described using one-dimensional differential equations, with the vertical transport by jets modeled using integral techniques. This allows very large reductions in computational effort compared to three-dimensional CFD simulation. The BMIX++ (Berkeley mechanistic MIXing code in C++) code was developed to implement such ideas. This paper summarizes major models for the BMIX++ code, presents the two-plume mixing experiment simulation as one validation example, and describes the codes' application to the liquid salt buffer pool system in the AHTR (Advanced High Temperature Reactor) design. Three design options have been simulated and they exhibit significantly different stratification patterns. One of design options shows the mildest thermal stratification and is identified as the best design option. This application shows that the BMIX++ code has capability to provide the reactor designers with insights to understand complex mixing behavior with mechanistic methods. Similar analysis is possible for liquid-metal cooled reactors.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.699-706
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• 2011

This study has a purpose of examining technical feasibility of supplying the in-stream flow for the Gyobang cheon by using treated water from small wastewater treatment facilities as a decentralized option. To do this, the water and contaminant flow in study areas of the Gyobang cheon are defined from the context of the integrated urban water cycle, and analyzed by using the Urban Volume and Quality (UVQ) model. First, the UVQ model was built for the study areas of the Gyobang cheon and calibrated with observation data. Second, the decentralized options of the in-stream flow was explored with consideration of availability of water sources. The UVQ simulation then led to selecting the best option which would meet the criteria of water quantity and quality. It was finally concluded that using water sources out of study areas 1 and 2, adjoining the upper part of the Gyobang cheon, in the decentralized manner can be a feasible option for in-stream flow. It also seems that the UVQ model is useful to understand the water cycle in study areas of the Gyobang cheon.

• English Language & Literature Teaching
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• v.13 no.2
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• pp.63-90
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• 2007

The present study investigated what combination of three form-focused options - explicit explanation, production practice, and corrective feedback - may be effective in helping low-proficiency learners improve accuracy in communicative writing. The subjects were 34 Korean university students enrolled in 'Business English 1' and the study lasted 11 weeks. The relative clause structure was selected as the target structure. The study found that the combination of explicit explanation, sentence-level production practice, communicative writing practice, and recasts had a significantly greater effect on improved accuracy than the combination of communicative writing practice and recasts and that of explicit explanation, communicative writing practice, and recasts. Because the second and third combinations didn't lead to significantly improved accuracy, it can be concluded that of the form-focused options forming the first combination sentence-level production practice made a decisive contribution to the significant increase in accuracy. It also found that the provision of self-correcting opportunities before providing recasts on errors committed in sentence-level production practice resulted in significantly greater accuracy in communicative writing than the provision of recasts alone on them. The results of the study suggest that we should make low-proficiency Korean learners have sentence-level production practice which is intensive and focused and make them self-correct targeted errors before providing them with narrowly focused recasts in order to help them to improve writing accuracy.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.23 no.2
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• pp.209-233
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• 2012

In this study in order to verify the overall information seeking behavior of the Web-based OPAC users, it was analyzed transaction log file for 7 years. Regarding Web-based OPAC information seeking behavior, it was studied from the perspective of information seeking strategy and information seeking failure. In search strategy, it was analyzed search type, search options, Boolean operator, length of search text, number of uses of word, number of use Web-based OPAC, number of use by time, by week day. Also, in search failure, search failure ratio, search failure ratio by search options, search failure ratio by Boolean operator were analyzed. The result of this study is expected to be utilized for OPAC system and service improvement in the future.

• Korean Journal of Social Welfare
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• v.45
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• pp.72-100
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• 2001

Despite the rapid expansion of social security coverage in the 1990s, many wage earners in Korea, especially the majority of the nonstandard workforce are excluded in the social insurance programs. In this regards, the purpose of this paper is to analyze causes of the exclusion of nonstandard workers to the social insurance scheme and to suggest the feasible policy options. Through this paper, four arguments are addressed as follows. First, the main issue for exclusion from coverage of those workers is that they have no entitlement to social insurance. This is not an issue of that they fall below hours or income thresholds for the entitlement Second, the top-down process of the extension in the Korean social insurances have divided the wage earners into two groups, the insider (the included) and the outsider (the excluded). Many nonstandard workers belong to the latter category. Third, the social insurance systems have been designed for the regular workers who were characterized by a full-time with some degree of stability. Reform designed to cope with the growth of nonstandard workers must build on the existing structure of social insurance. Finally, the governance capacity by social security administration body must be improved in order to provide a basic social protection for those workers. For that, four separated social insurance administration bodies could be unified to one administrative body, or tax and contribution of social insurance could be collected by one integrated administration body, the National Tax Service.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.05a
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• pp.181-190
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• 2002

전자 카탈로그 상에서의 상품 검색은 카탈로그에 명시되어 있는 상품을 찾는 표준상품검색과 소비자가 원하는 상품을 맞춤 하는 맞춤상품검색으로 분류할 수 있다. 현재의 대부분의 상품 검색은 표준상품검색에 의존하고 있다. 특히 기업간 구성요소기반(Component-based) 상품의 경우 표준상품검색만으로는 구매자의 다양한 요구에 응하기가 어렵다. 따라서 웹 상의 전자 카탈로그에서의 동적인 맞춤검색에 대한 요구가 증가하고 있다. 본 연구에서는 구성기반 상품에 대해서 표준상품검색만으로는 구매자가 원하는 상품의 검색가능성(Feasibility)과 검색된 대안들이 조정(Adjust) 프로세스 과정을 거쳐 최적해 도달 가능성(Admissibility)이 보장되지 않음을 보이고, 이에 대한 효과적인 방법론으로 검색가능성과 최적해 도달 가능성을 지원하는Template-based Reasoning 방법론을 제안 한다. Template-based Reasoning은 구매자의 요구사항에 따른 대안탐색 부분과 선택된 대안에 대한 조정과정의 두 단계로 이루어진다. 구매자의 주요 선호도(MUST Preference)에 근거하여 대안들을 탐색하고, 탐색 된 대안들 간의 우선순위를 결정한다. 조정 단계에서는 옵션(Options)의 확장을 통해 구매자의 맞춤사양에 따른 상품을 제안하고, 제약 및 규칙기반 추론(Constraint and Rule Satisfaction Approach)을 이용하여 옵션(Options)들 간의 제약조건에 따른 호환성(Compatibility)을 조사하고, 적정가격의 상품을 제안한다. 본 방법론은 Template을 사용하여 기본적으로 구매자가 원하는 상품을 검색하기 위한 검색노력을 줄이고, 검색된 대안들로부터 구매자와 시스템이 웹상에서 서로 상호작용(interactivity) 하여 해를 찾고, 제약조건과 규칙들에 의해 적합한 해를 찾아가는 방법을 제시한다. 본 논문은 구성기반 예로서 컴퓨터 부품조립을 사용해서 Template-based reasoning 예를 보인다 본 방법론은 검색노력을 줄이고, 검색에 있어 Feasibility와 Admissibility를 보장한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.395-399
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• 2002

The UK mobile market continues to grow as much as 73 percent of UK adults had a mobile telephone in August 2001. As a result of increasing competition, market shares of 4 operators, Vodafone, BTCellnet, One2One, Orange, in the UK mobile market become to be balanced. This paper examined driving factors for increasing competition and balancing market in the UK mobile market. In the Korean mobile market, leading operators' market share continues to be bigger than new entrants. Users have been decreased opportunity selecting operators by M&A. This paper discussed the policy options for the effective competition in the Korean mobile market based on the case of the UK mobile market.

• Journal of Magnetics
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• v.20 no.2
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• pp.176-185
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• 2015

We present the design optimization of the magnetic pole and slot design options that minimize the cogging torque of permanent-magnet (PM) brushless generators for small wind turbine generators. Most small wind-turbines use direct-driven PM generators which have the characteristics of low speed and high efficiency. Small wind-turbines are usually self-starting and require very simple controls. The cogging torque is an inherent characteristic of PM generators, and is mainly caused by the generator's geometry. The inherent the cogging torque can cause problems during turbine start-up and cut-in in order to start softly and to run a power generator even when there is little wind power during turbine start-up. Thus, to improve the operation of small turbines, it is important to minimize the cogging torque. To determine the effects of the cogging torque reductions, we adjust the slot opening width, slot skewing, mounting method of magnets, magnet shape, and the opening and combinations of different numbers of slots per pole. Of these different methods, we combine the methods and optimized the design variables for the most significant design options affecting the cogging torque. Finally, we apply to the target design model and compare FEA simulation and measured results to validate the design optimization.

• The Journal of Korean Obstetrics and Gynecology
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• v.31 no.1
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• pp.99-121
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• 2018

Objectives: Genital herpes is common disease in gynecological field. Although various treatment options such as herbal medicine, acupuncture, moxibustion are used in genital herpes, there is not enough evidence about the treatment options. This study is to prove the efficacy of oriental medicine on genital herpes by investigating papers and suggest direction of future research. Method: We searched for papers which had both genital herpes and oriental medicine from Cochrane, Pubmed, Scopus, CNKI, Oasis, Korean traditional knowledge portal, Journal of Korean Obstetrics & Gynecology up to November 2017. After searching papers, we classified according to the study design and analyzed selected studies. Results: Sixteen papers were finally selected. Four papers are laboratory studies with Hartley guinea pig with recurrent genital herpes. Twelve papers are clinical trials which includes one single group trial, one controlled trial, ten randomized controlled trials. All of the studies have shown that herbal medicine is effective in improving the symptom of genital herpes and decreasing the recurrent rate of genital herpes and also has immunoregulatory effect. Conclusions: This study shows that herbal medicine could be a good treatment option for genital herpes. However, more well-designed clinical studies and laboratory studies will be needed.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.14 no.1
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• pp.141-157
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• 2003

This study investigated relocations and expansions of DDC for the Korean university libraries using DDC to develop the standard relocations and expansions suitable for Korean situations. Contents of the standard relocations and expansions of DDC suggested by this study are as followed : Table2, Table5 and Table6. Also included are the Generalities class, Oriental philosophies from the Philosophy class, Buddhism and the oriental-origin religions from the Religion class, Public administration for the Social sciences class, the Language class, the Literature class, and the General geography and history class. The major characteristics of this study is that the standard relocations and expansions of DDC is followed by the options in DDC although it is followed by the basic systems in case that the options are not allowed.