• 설비공학논문집
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• 제6권1호
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• pp.39-46
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• 1994

Experiments on the performance of refrigeration system using alternatives to R12 are carried out. The condenser and the evaporator are concentric-tube heat exchangers of counter-flow type and the compressor is driven by a variable speed motor. In this study, R134a, R152a, R22/142b(50 : 50 by mass) are adopted as alternatives to R12. Tests are performed by varying the inlet and outlet temperatures of secondary fluids of evaporator and condenser under the condition of constant compressor speed, degree of superheating and degree of subcooling. Results show that R134a has refrigeration capacity close to that of R12 and requires the greatest compressor power compared with that of others. And the system using R152a shows the best performance from the viewpoint of refrigeration capacity, compressor power and coefficient of performance. R22/142b is superior to R12 in the above points.

• 한국태양에너지학회 논문집
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• 제36권2호
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• pp.53-63
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• 2016

Building Integrated Photovoltaic (BIPV) is one of the best ways to generate electric power using the solar energy, which is clean and inexhaustible energy resources. The most of BIPV modules have the form of GtoG (Glass to Glass) photovoltaic in building applications. Degradation leading to failure in photovoltaic modules is very important factor in BIPV modules. This paper analyzed the performance of various BIPV modules through outdoor exposure tests. Performance of three BIPV modules(c-Si type, a-Si type and DSSC type) with three installation angles influenced by sun light, outdoor temperature, and wind velocity was monitored and analyzed. As a result, c-Si type BIPV module outperforms other BIPV modules(a-Si type). In terms of power efficiency of the module, the installed angle of $45^{\circ}$ is better than others(90 degree, 0 degree). In addition, more realistic data of various BIPV system performance could be available through the field test and integrated building test. In this study, relationship of the BIPV system is identified module's installation angle, power generation, architectural performance, etc.

• 한국간호교육학회지
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• 제19권4호
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• pp.508-517
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• 2013

Purpose: The purpose of this study was to evaluate the effectiveness of infant CPR (Cardiopulmonary Resuscitation) immediate remediation[LAB2]. Methods: This is a quasi-experimental study with a non-equivalent comparison group pre-post test design. Participants were 73 child care teachers in J district in Seoul. The experimental group (35) received immediate remediation with video learning [LAB3]for infant CPR education and the control group (38) received video learning only. We investigated confidence of infant CPR and tested single-rescuer infant CPR performance depending on a checklist (8 items). Data were collected before and right after to evaluate the confidence of infant CPR and before, right after and 2 weeks after the education to evaluate the skill performance and final acceptance. Results: There was a significant increase in confidence of infant CPR in the experimental group and control group. There was a statistically significant difference in the degree of skill performance between groups according to the amount time (F=10.58, p<.001). The degree of skill performance was tested two weeks after the education and immediate remediation was 5.35 times more effective compared to the video image demonstration (B=1.677, p<.001). Conclusion: The findings provide the necessity of immediate remediation education of infant CPR to increase confidence and skill performance ability.

• 한국게임학회 논문지
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• 제10권6호
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• pp.57-65
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• 2010

본 논문에서는 6자유도를 갖는 병렬형 기구의 출력 속도 공간에서 성능을 평가할 수 있는 지표를 제안하였다. Manipulability와 condition number에 기반을 둔 성능 지표가 단위계의 볼일치로 인한 물리적 의미의 결함이 없도록 출력공간을 병진속도 공간과 회전속도 공간으로 분리하는 방법을 제안하였다. 각 공간에서 단위 입력에 대용하는 mobility ellipsoid를 정의하여 이를 기반으로 병진운동 출력공간에서 두 종류 성능 지표와 회전운동 공간에서 두 종류의 성능 지표를 제안하였다.

• 한국식품조리과학회지
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• 제14권5호
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• pp.482-491
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• 1998

The objectives of this study were to characterize the food service managements in university food services. In a survey involving university food service centers throughout the country, the importance, performance scores and policies for food service management were investigated. Of the total 40 institutions surveyed, 23 were run directly by the institution, eight by contract, and nine by rental. Data were analyzed by t-test, ANOVA using the SPSS program. Management system was evaluated separately for organization, human resources, finance, nutrition education, purchasing, quality control, sanitation and safety, and marketing for their relative importance, degree of performance, and policy establishment. It was found that the relative importance scored higher than the degree of performance and policy establishment. When rhe relative importance for the direct, contract and rental operations was compared, the rental operation scored the highest. Performance score of direct was the highest in direct operation. The findings of this research suggest that the university food service should be creative through systematic management, and further research is needed to evaluate various variables that influence productivity, such as employee morale, pleasant working environment, customer satisfaction, and introduction of TOM for university food services.

• Smart Structures and Systems
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• 제1권3호
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• pp.235-256
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• 2005

The non-linear behaviour of electrorheological (ER) and magnetorheological (MR) dampers makes it difficult to design effective control strategies, and as a consequence a wide range of control systems have been proposed in the literature. These previous studies have not always compared the performance to equivalent passive systems, alternative control designs, or idealised active systems. As a result it is often impossible to compare the performance of different smart damper control strategies. This article provides some insight into the relative performance of two MR damper control strategies: on/off control and feedback linearisation. The performance of both strategies is benchmarked against ideal passive, semi-active and fully active damping. The study relies upon a previously developed model of an MR damper, which in this work is validated experimentally under closed-loop conditions with a broadband mechanical excitation. Two vibration isolation case studies are investigated: a single-degree-of-freedom mass-isolator, and a two-degree-of-freedom system that represents a vehicle suspension system. In both cases, a variety of broadband mechanical excitations are used and the results analysed in the frequency domain. It is shown that although on/off control is more straightforward to implement, its performance is worse than the feedback linearisation strategy, and can be extremely sensitive to the excitation conditions.

• 한국간호교육학회지
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• 제10권1호
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• pp.44-53
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• 2004

Purpose: This research was to grasp task performance of the Preceptor and to offer the basic data to a Preceptorship establishment. Method: 208 Preceptors which have been working at three 3rd medical institutions of Seoul. A task performance degree of Preceptor has been measured using a questionnaire which modifying and supplementing Schiwirian's tool(1974) The collected data was analyzed into description statistics, t-test and ANOVA through the SPSSWIN program. Result: The task performance degree was a $4.06{\pm}.51$ score. Personal relations and understanding was the highest area with a $4.31{\pm}.50$ score and patient education was the lowest area with a $3.69{\pm}.58$ score. the service career as a nurse is more than nine years(F=3.122, P=.027), worked as the Preceptor for more than five years to less than a seven year period(F=3.499, P=.016), the number of new nurses to educate as a Preceptor is more than five(F=3.509, P=.009), it has been evaluated as a good task performance. Conclusion: The selection of competent Preceptor and the development of the education program for Preceptors are required to deal with their task effectively. Above all, the task achieved successfully can be contributed to a Preceptorship establishment.

• 한국구조물진단유지관리공학회 논문집
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• 제7권3호
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• pp.167-174
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• 2003

우리나라 군 시설에서 조적조가 차지하는 비중은 매우 크며, 군 시설 현대화사업의 추진 등으로 성능에 대한 정확한 평가가 없이 노후 시설물을 철거하는 경우가 있어서 낭비를 초래하고 있다. 본 연구는 조적조 노후 군시설을 효율적으로 유지보수 하는데 도움을 주기 위해서 시설물의 기울기 및 침하, 내하력, 내구성 등을 조사하여 시설물 전반의 성능을 객관적으로 평가할 수 있는 기준을 제시하였다. 내하력은 조적상태, 줄눈모르터 상태, 긴결철물의 상태, 테두리보 상태, 하중상태 등으로 평가하고, 내구성은 균열, 표면노후화, 진동등의 항목으로 평가하도록 하였다. 평가항목의 중요도는 AHP 기법을 적용하여 산정한 가중치로 결정하였다. 조사대상 조적조 노후 군시설의 성능을 판정할 수 있는 절차도 제시하였으며, 사례연구를 통하여 본 연구에서 제시한 평가기준의 적용성을 확인할 수 있었다.

• 한국구조물진단유지관리공학회 논문집
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• 제17권4호
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• pp.91-100
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• 2013

이 연구에서는 기존아파트 외벽체의 단열 성능저하 및 보수보강에 필요한 기초 자료를 만들기 위해서 아파트의 구조체 단열성능 측정분석과 함께 단열하자에 대한 기준수립 및 평가를 하고자 한다. 또한 아파트 건축물 구조체의 열교 및 결로발생 부분을 예측하고자 하였다. 한편 시공연도별 분석에 의하여 단열기준 및 시간 경과에 따른 단열성능 정도를 분석하기 위함이다.

• 한국수소및신에너지학회논문집
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• 제32권6호
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• pp.585-591
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• 2021

Liquefied hydrogen have advantage which reduces the volume by about 800 times or more compared to hydrogen gas, so it is possible to increase the storage density. However, liquefied hydrogen produced by cryogenic cooling of 20 K or less at normal pressure has a problem of maximizing the insulation effect that blocks heat introduced from the outside. Representative insulation technologies include vacuum insulation and multi-layer insulation materials and in general, heat blocking is attempted by combining insulation technologies. Therefore, in this study, the pressure of the internal vacuum layer was changed to 10^-1, 10^-2, 10^-3 and 10^-4 Torr to confirm the thermal insulation performance of the vacuum jacket valve for transporting liquefied hydrogen. As a result, it was confirmed that the insulation performance improved as the degree of vacuum increased.