• 한국군사과학기술학회지
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• 제13권4호
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• pp.612-618
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• 2010

In order to successfully manage of the state-of-the-art weapon system R&D program which are under the limited budget and schedule but also has a high level of technical risks, it is gaining weights to use such a scientific program management tool as TPM. Therefore, the purpose of this research is to review the concept of the TPM and its relation among MOE, MOP and TPM, and introduce an application method of TPM mainly focusing on helicopter development program. It has the organized structure, detailed procedure and 282 parameters for performance management through the TPM.

• 설비공학논문집
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• 제23권7호
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• pp.505-512
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• 2011

Recently, many researchers have analyzed the performance of the transcritical $CO_2$ refrigeration cycle in order to identify opportunities to improve the system energy efficiency. The reduction of the expansion process losses is one of the key issues to improve the efficiency of the transcritical $CO_2$ refrigeration cycle. In this study, the analytical study on the performance characteristics of $CO_2$ cycle with an ejector carried out with a variation of outdoor temperature, gascooler inlet air velocity, evaporator inlet air velocity, and evaporator inlet air temperature. As a result, the system performance could be improved over 85% by using an ejector for various operating condition because of the reduction of compressor work. Moreover, the cooling capacity increased about 18% for variable outdoor condition. Therefore, the high performance of an ejector system could be maintained for wide operating conditions and system reliability could be improved compared to that of a basic system.

• 한국자동차공학회논문집
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• 제4권6호
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• pp.153-163
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• 1996

An expert system to design compressor valve systems has been developed. Design process is viewed as a chain of devisions based on the results of necessary analyses. Actual design is implemented by the interaction between the expert system and the user. In this work, it is demonstrated how a final design is achieved by utilizing the rule bases and analysis capability of the system. The structure of the rule bases and related parameter studies are also explained. Advantages of using an expert system approach for valve designs are explained using a practical example.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.111-114
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• 2006

Recently, it is increased on the concern for the reuse of waste concrete because of the shortage of natural aggregate and the increase of waste concrete. And recycled coarse aggregate is used variously, but the existing wet method producted recycled fine aggregate has problem like the high price facilities, the long time progress of the work and the poor of recycled fine aggregate. The aim of this study is to investigate outline and performance evaluation of the drying specific gravity separation method to product high duality recycled fine aggregate. Finally, this study is shown investigate process flowing of drying separation type with gravity manufacture, producte system and function of detail devices. The performance of the method of drying specific gravity separation is certificated as the qualities of recycled fine aggregate satisfied the KS

• Journal of Advanced Marine Engineering and Technology
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• 제38권7호
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• pp.828-833
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• 2014

본 연구는 이젝터 팽창기를 적용한 냉동기에서 팽창한 냉매가 액기분리기에 포집된 후, 이 중 포화기체의 일부는 이젝터로 재흡입되고, 포화액체는 증발기에 유입되어 증발된 후 액기분리기의 잔여 기체와 혼합되어 압축되는 공정을 고안하여 특성을 해석하였다. 본 공정의 특성은 이젝터에서 등엔트로피 팽창 후 액체량의 증가로 냉동능력이 증가하고, 압축기에 유입되는 기체의 압력이 상승하게 되어 압축일이 감소함으로써 효율이 증가하게 된다. 냉매 R134a를 적용하는 냉장고 시스템과 본 고안 시스템을 비교한 결과, 이젝터에서 압력이 65% 저하될 때 COP는 27.8%가 증가된 최대값이 되었다. 다른 냉매의 경우 R401A가 75% 압력강하에서 40.1%의 COP 증가를 보였다. 이젝터의 디퓨져에서의 압력 상승율이 20%~60%까지 변화될 때, COP 증가율은 2.6%~3%로 영향이 매우 적었다.

• 한국건축시공학회지
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• 제7권4호
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• pp.153-159
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• 2007

Recently, as a result of the economic growth, the concentration of population towards the cities and the rise in land prices, the demand for high rise buildings has increased significantly, the trend to build high rise buildings such as the mixed-use development buildings by the domestic construction companies continues. It's very important what kind of form work system is applied on the Core Wall of the high rise buildings to determine the economic efficiency for the whole project. That's because the appropriate selection of the Formwork system enables the construction cost lower, makes the good quality of the finished concrete, reduces the construction period, assurance of safety, and further more, it enables to achieve the successful performance of the projects. Therefore, this research, after comparing the strength and the weakness between the construction methods, focus the point to provide a builder the basic data to choose the right Formwork method.

• 한국건설관리학회논문집
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• 제6권5호
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• pp.78-88
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• 2005

공동주택의 비중이 점차 확대되고, 고층화되는 추세에 따라 공동주택 유지관리의 중요성이 강조되고 있다. 이러한 필요성에 의해 최근 기존 건축물의 종합성능 평가모델이 개발되었으나, 업무의 분석이 미흡한 한계가 있다 따라서 본 연구는 공동주택 유지관리 성능평가의 기반이 되는 유지관리 업무를 분석하여 성능평가 대상항목 도출을 목적으로 한다. 유지관리 성능평가 후보항목은 기존문헌과 업무체계를 분석하여 도출하였고, 학계 전문가 및 주택관리사를 대상으로 설문을 실시하여 성능평가의 용이성, 체계성을 보완하였다. 최종적으로 결정된 성능평가 대상항목은 운영적 유지관리 성능평가 항목 14개와 기술적 유지관리 성능평가 항목 15개 항목이다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제23회 학술대회
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• pp.53-59
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• 1996

The new trends in main spindle design of Machining Center are focused on high-speed, high-precision and high-stiffness. As a main spindle bearing, the angular-contact ball bearing is well used. A rolling bearing is usually only a small part of a larger mechanical system, but its performance can have a great influence on the functioning of the whole machine. This work is about fatigue life tester design and monitoring of defected rolling-element bearings. The major work is done via experiments and the vibration signal is analysised by means of frequency spectrum technique. By analyzing the frequency spectrum, it is possible to view the condition of the bearings.

• 한국융합학회논문지
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• 제10권3호
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• pp.265-274
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• 2019

본 연구는 교원성과급제도에 대한 고등학교 교사들의 주관성을 탐색하는데 목적이 있다. 이를 위해 인간의 주관적 인식을 탐색할 수 있는 Q방법론을 활용하였다. 연구결과 3개의 유형이 탐색되었다. 제1유형은, '성과급제 부정형'으로 연구 참여 교사 24명 중 20명, 약 83%가 포함되었다. 교원성과급제도에 대해 정부의 일방적 정책 시행에 대한 불만, 불필요한 스트레스 야기 그리고 교원 간 갈등 및 경쟁 등을 유발하고 교사들의 동기유발이나 직무만족도에는 오히려 부정적인 영향을 준다는 인식을 나타냈다. 제2유형은 '성과급제 중립형'으로 성과급제 대해 공정한 업무 평가와 교육공동체의 협력적 분위기 강화, 직무만족도 증대 등에 긍정적 인식을 나타냈으나, 교직에 대한 자긍심 증대나 교육적 행동 유발 등에 대해서는 부정적 인식을 나타냈다. 제3유형은 '성과급제 수용형'으로 성과급제는 기피업무에 대한 보상이면서 교원의 동기유발 및 직무만족도를 높이고 참여적 업무수행과 창의적 업무 수행 등에 대해 긍정적 인식을 나타냈다. 끝으로, 모든 유형에서 성과급제의 평가 척도의 타당도에 부정적 반응을 나타냈다.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.120-127
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• 2013

Hybrid electric vehicles have applied electric parts for saving fuel consumption and reducing levels of environmental pollution. Electrification of automobiles is indispensable for entering into global market because of enhanced environment restriction. ISG (Integrated Starter & Generator) system is one of main electric parts and can improve fuel efficiency more than other components by using Idle Stop & Go function and regenerative braking system. However, if ISG motor and inverter work under the continuously high load condition, it will make them the decrease of performance and durability. So the ISG motor and inverter need to properly design the cooling system of them. In this study, we suggested the enhancement points by modifying the thermal design of ISG motor and then confirmed the improvement of the cooling performance.