• Journal of Advanced Marine Engineering and Technology
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• 제34권8호
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• pp.1050-1056
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• 2010

디젤기관은 공기만을 흡입 압축한 후에 연료를 분사하여 연소하기 때문에 높은 압축비가 가능하다. 높은 압축비에 의한 고효율의 장점과 연료의 직접분사에 의한 매연미립자의 배출 및 질소산화물의 배출이 많은 단점을 갖고 있다. 이러한 문제점을 해결하기 위하여 많은 연구들이 진행되었으며 수소를 흡기중에 공급하는 기술도 연구되고 있다. 본 논문에서는 미량의 수소를 연소실에 공급하여 엔진성능에 미치는 영향을 평가하였다. 토크와 엔진속도를 100%, 75%, 50%, 25%, 0%와 700rpm, 1000rpm, 1500rpm, 2000rpm로 구분하여 실험하였다. 실험결과 질소산화물이 약간 증가하였지만 연료소비율, 스모크와 일산화탄소 배출은 감소하였다. 수소의 첨가는 저부하 영역에서는 효과가 거의 없었지만 고부하 영역에서 큰 효과가 있었다.

• 한국경영과학회지
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• 제37권4호
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• pp.1-18
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• 2012

With the enormous growth and various applications of private brands, national brand manufacturers are confronted with a dilemmatic situation. That is, paradoxically, some manufacturers have come to produce private brands of retailers which are potential competitors to their own brands. This study reveals why manufacturers with their own brands let themselves do the consignment production of retailers' private brands although those private brands may become strong competitors of their own brands and then investigates the condition in which manufacturers may benefit from such consignment production. Through an analysis of a game theoretical model assuming a monopoly market, the present study presents the theoretical backgrounds and provides new insights about consignment production of manufacturer with its own brand for retailer's private brand. First, such consignment production can play a role in mitigating the loss in the consignee manufacturer's own brand sales caused by the private brand in the competitive environment. Second, the effectiveness of such role is affected by the quality of the private brand produced under consignment. In other word, only if the consignee manufacturer keeps the quality of the private brand low, the manufacturer can maintain the benefit from its own brand. In addition, a consigner retailer needs to consider the final objective of launching its private brand, when it chooses its consignee manufacturer of the brand. Finally, a manufacturer with its own brand may consider consignment production as not merely an unavoidable option compelled by a retailer's power but a reasonable strategic choice to reduce the risk from competition.

• 한국도서관정보학회지
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• 제41권3호
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• pp.25-46
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• 2010

이 연구에서는 2009년 조선일보가 주관한 "시골학교에 도서관을" 캠페인에 신청한 119개 시골 초등학교 도서관의 현황을 분석하였다. 이 학교들의 신청서를 내용분석 방법을 사용하여 검토하고, 시설, 장서, 환경의 측면에서 현황과 특성을 기술하였다. 이 학교도서관들은 전체 장서 규모, 1인당 장서 증가 규모 등 수치상으로는 무난하다고 보인다. 그러나 거의 공통적으로 낡고 열악한 시설, 장서의 부족, 불균형과 낮은 질, 재정지원의 부족, 문화적 고립 등 문제를 가진 것으로 나타났다. 이들이 전형적 시골학교 도서관이 아니라고 해도 통계 수치만으로 알 수 없는 학교도서관 현실의 일면을 보여준다. 이 연구에서는 지방자치단체와 교육청 등의 인식 변화와 재정 지원이 가장 시급한 해결책임을 인식하고 다음을 제안하였다: 첫째, 학교도서관 관련 정책이 유권자들의 관심거리임을 주지시켜야 한다. 둘째, 기존의 각종 도서관 평가와 시상제도의 가시성을 활용해야 한다. 셋째, 각종 도서관 평가에서 질적 측면을 강화해야 한다.

• 한국건설관리학회논문집
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• 제11권3호
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• pp.3-12
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• 2010

최근 국내 외의 건설 프로젝트는 이해관계가 복잡해서 업무 흐름을 파악하기 어렵기 때문에 IETM(Interactive Electronic Technical Manual)을 이용하여 사업 참여자들의 의사결정을 지원하려는 연구가 진행되고 있다. 본래 IETM은 신속한 정보 처리가 가능해서 타 분야에 도입되었으나, 건설 사업은 정보의 변화 가능성이 높아서 정보 유지관리에 어려움이 있어 활성화 되지 못했다. 본 연구에서는 건설 사업관리 IETM이 정보 변화성을 수용하고 정보를 지속적으로 유지관리하기 위한 방법으로 위키의 정보 관리기능에 주목하여 위키 기반 시스템의 성공사례를 바탕으로 특성을 분석하고 건설 분야 적용을 위한 요소를 추출하였다. 이를 바탕으로, 건설 사업의 이해관계로 인한 의도적 파괴를 방지하고 프로세스 중심의 특성을 반영하기 위한 IETM 시스템 모델을 제시하고 건설 사업관리 분야의 특성을 대표할 수 있는 도시환경정비사업 절차에 대한 IETM 프로토타입을 구현하였다. 파일럿테스트 결과, 위키 기반 전자매뉴얼은 유지관리측면에서 기존의 결과 중심적인 지식 형성 과정에 의사소통을 가능하게 함으로써 건설 사업 수행 중의 의사소통 프로세스를 개선할 수 있는 것으로 나타났다.

• 대한기계학회논문집B
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• 제29권7호
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• pp.828-836
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• 2005

Impingement/effusion cooling technique is used for combustor liner or turbine parts cooling in gas turbine engine. In the impingement/effusion cooling system, the crossflow generated in the cooling channel induces an adverse effect on the cooling performance, which consequently affects the durability of the cooling system. In the present study, to reduce the adverse effect of the crossflow and improve the cooling performance, circular pin fins are installed in impingement/effusion cooling system and the heat transfer characteristics are investigated. The pin fins are installed between two perforated plates and the crossflow passes between these two plates. A blowing ratio is changed from 0.5 to 1.5 for the fixed jet Reynolds number of 10,000 and five circular pin fin arrangements are considered in this study. The local heat/mass transfer coefficients on the effusion plate are measured using a naphthalene sublimation method. The results show that local distributions of heat/mass transfer coefficient are changed due to the installation of pin fins. Due to the generation of vortex and wake by the pin fin, locally low heat/mass transfer regions are reduced. Moreover, the pin fin prevents the wall jet from being swept away, resulting in the increase of heat/mass transfer. When the pin fin is installed in front of the impinging let, the blockage effect on the crossflow enhances the heat/mass transfer. However, the pin fin installed just behind the impinging jet blocks up the wall jet, decreasing the heat/mass transfer. As the blowing ratio increases, the pin fins lead to the higher Sh value compared to the case without pin fins, inducing $16\%{\~}22\%$ enhancement of overall Sh value at high blowing ratio of M=1.5.

• 대한지구과학교육학회지
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• 제8권1호
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• pp.66-75
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• 2015

This study is to investigate an argumentation level for elementary school students after analysing an argumentation structure about a socio scientific issue(SSI), and inquire a change of the decision-making according to the refutation materials and empathic situation. This data was collected from the semi-structured interview with the 14 students, grade 6th. For this, the first stage is to present the reading materials about the SSI to the students, let them decision-making and make them argue pro and con about the SSI during the interview. After that, facing with the refutation materials against the existing contention and the empathic situation, the change of the decision-making of the students was conducted. After the research, the level of the argumentation of the students was low, and the students who didn't have the background knowledge about the theme made the decisions according to the values, emotions or intuitions of their own. And the decision-making of the students changed more when presented with the refutation materials and the empathic situation, they were difficult to make the decision because of new information and various stances. Besides, they lacked in the ability that recognize the situation related with their own life, just used the fragmentary knowledge associated with value of life respect. Through these result, it is necessary to produce the refutation materials and empathic materials about the SSI to the students for improving the level of argumentation.

• 한국초등과학교육학회지:초등과학교육
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• 제20권1호
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• pp.59-73
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• 2001

The National Science Fairs has been held in every year for the promotion of science and technology and scientific civil life. The purpose of this study is to survey the current problems in National Science Fairs by making up a question and to improve them. The study makes up a questionnaires about the existing Science Fairs to the teachers who have submitted their works to the Science Fairs and suggest the ways of improvement. The result of questionnaires is that little availability of reference materials, difficulty of paying proper attention to regular classes because of frequent travels, and absence of experimental devices and experimental rooms are perceived as major obstacles in preparing for the exhibition. Respondents teacher also pointed out some problems with the current organization of the exhibition; non-voluntary selection process for the potential authors, separation of research content from regular teaching materials, unrealistically high standard, low participation rate of teachers, so many exhibited works, lack of professionalism in the screening process. The majority however, agreed that the exhibition event should be continuously done, after remedial measures have been taken about the problems. First, the side of science education is emphasized in a purpose of the science fairs to let activity related to science fair be closely connected with school education. Second, students have to be divided according to grade. Third, research level have to be set not too higher than regular instruction content. Fourth, hand book related to science fairs have to be manufactured and spread. Fifth, data of local science fair have to be arranged. Sixth, judging section have to be subdivided and people related to science education have to be included to a judge. Seventh, excellent works have to be support to participate in ISEF.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.184-192
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• 2008

현재, 전 세계적으로 건설 산업의 문제점으로 인식되고 있는 낮은 생산성, 숙련공 부족, 인력의 부족, 높은 재해율 등을 해결하기 위한 방법으로 낙후된 건설 생산시스템의 첨단 기술화를 위한 건설 자동화연구가 활발히 진행되고 있다. 국내에서도 1980년대부터 건설자동화 연구가 진행되고 있으며 기계화 및 반자동화를 통한 생력화를 위한 연구가 주로 진행되었다. 그러나 최근 IT기술의 비약적 발전과 함께 건설 로봇의 개발에 대한 관심이 집중되고 있으며 2006년 말부터 국토해양부의 건설기술혁신사업의 일환으로 토공자동화를 위한 지능형 굴삭시스템이 개발되고 있다. 본 논문에서는 지능형 굴삭시스템의 최종 개발 목표와 2차 년도까지 진행된 연구내용에 대하여 소개하고자 한다.

• Journal of Information Processing Systems
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• 제15권6호
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• pp.1277-1295
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• 2019

With its technical development, digital printing is being universally introduced to the mass production of clothing factories. At the same time, many fashion platforms have been made for customers' participation using digital printing, and a tool is provided in platforms for customers to make designs. However, there is no sufficient solution in the production stage for automatically converting a customer's design into a file before printing other than designating a square area for the pattern designed by the customer. That is, if 30 different designs come in from customers for one shirt, designers have to do the work of reproducing the design on the clothing pattern in the same location and in the same angle, and this work requires a great deal of manpower. Therefore, it is necessary to develop a technology which can let the customer make the design and, at the same time, reflect it in the clothing pattern. This is defined in relation to the existing clothing pattern with digital printing. This study yields a clothing pattern for digital printing which reflects a customer's design in real time by matching the diagram area where a customer designs on a given clothing model and the area where a standard pattern reflects the customer's actual design information. Designers can substitute the complex mapping operation of programmers with a simple area-matching operation. As there is no limit to clothing designs, the variousfashion design creations of designers and the diverse customizing demands of customers can be satisfied at low cost with high efficiency. This is not restricted to T-shirts or eco-bags but can be applied to all woven wear, including men's, women's, and children's clothing, except knitwear.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.459-465
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• 2007

This study was conducted to calculate the LCC of a apartment complex with a type of heating system, district heating and cogeneration system. For the purpose of analyzing LCC according to size of apartment complex, 500, 1,500 and 4,000 houses of model apartment selected. This research performs design of heating system and the life cycle cost analysis including an initial cost, energy cost, maintenance and operation cost, replacement cost and renovation cost during the project period(15years). According to the calculated results, 1) Initial cost of cogeneration system with 500, 1500 and 4000 houses is higher than district heating system each of 20%, 13%, 12%. 2) In case of cogeneration system, the payback period by electric generation is 5.21, 4.92 and 4.47 years and saving cost was calculated 29 billion won, 94 billion won and 262 billion won after payback period. 3) Cogeneration system LCC was 1.12, 1.07 and 1.06 times larger than district system with the size of apartment complex. According to the case of this study district heating system is more efficient than cogeneration system in terms of the reduction of LCC. 4) Gas Engine Co-generation System is more efficient than other systems because it can collect progressive part from electric charge progressive stage system. However, the efficiency is decreasing because of raising of fuel bills(LNG) and lowering of power rate for house use. Especially the engine is foreign-made so the cost of maintenance and repair is high and the technical expert is short. 5) District heating is also affected by fuel bills so we should improve energy efficiency through recovering of waste heat(incineration heat, etc.). Also, we should supply district cooling on the pattern of heat using of let the temperature high in winter and low in summer.