• 전력전자학회논문지
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• 제17권6호
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• pp.553-561
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• 2012

Existing energy sources convert chemical energy into mechanical energy, while fuel cell directly generates electricity through an electrochemical reaction between hydrogen and oxygen. Therefore, it has a lot of strong points such as high efficiency, zero emission, and etc. In addition, with the development of hydrogen preservation technique, some companies have been researching and releasing portable fuel cell power packs for specific applications like military equipment, automobile, and so on. However, there are some drawbacks to the fuel cell, high cost and slow dynamic response. In order to compensate these weak points, auxiliary energy storages could be applied to the fuel cell system. In this paper, the optimum structure for a 150W portable fuel cell power pack with a battery pack is selected considering the specification of the system, and the design process of main parts is described in detail. Here, main objectives are compact size, simple control, high efficiency, and low cost. Then, an automatic mode change algorithm, which converts the operating mode depending on the states of fuel cell stack, battery pack, and load, is introduced. Finally, performance of the designed prototype using the automatic mode change control is verified through experiments.

• 한국문헌정보학회지
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• 제44권4호
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• pp.413-433
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• 2010

이 연구는 공공도서관 디지털자료실을 구성하는 가장 중요한 요소인 정보자원의 유형별 중요성을 파악하고자한 사례연구이다. 공공도서관의 수적 증가와 함께 디지털 정보원을 매개로 한 정보서비스의 고도화에 있어서도 많은 진전이 있었지만 현재 공공도서관의 디지털 정보자원은 주로 디지털자료실이라는 공간을 중심으로 소극적으로 관리되고 있으며, 디지털 정보원을 활용한 서비스도 활성화 되고 있지 못한 것이 현실이다. 이 연구에서는 그 원인을 콘텐츠에서 찾고자 하였다. 시설투자에 비하여 적정한 규모를 확보하지 못한 정보자원 측면의 문제점을 살펴보고 공공도서관에서 디지털 정보원을 수집, 관리하는데 있어서 기본이 되는 콘텐츠 측면의 요소들에 어떠한 것들이 있는지 파악하고 각각의 중요도를 조사함으로써 향후 공공도서관의 디지털 정보자원 관리를 위한 시사점을 제공하고자 하였다. 이를 위하여 관련 연구와 해외 주요 공공도서관 사례로부터 정보자원에 해당되는 요소들을 추출하였고 이를 바탕으로 전문가 서베이를 거친 후 도출된 정보자원 요소들과 중요도를 조사하여 제안함으로써 향후 공공도서관의 디지털 콘텐츠 구성에 참고가 되고자 하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제39권1호
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• pp.28-31
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• 2015

전기기기나 엔진의 축은 여러 가지 원인으로 축기전력이 발생한다. 이런 축과 베어링이 윤활유로 절연되어 있어 콘덴서를 이루고 있고, 콘덴서와 같은 역할로 기전력을 축적하고 있다. 이 축 기전력은 선체에 비해 극히 일부를 제외하고 +전압을 갖고 있다. 이 +전압이 축의 전기 스파크를 일으켜 부식을 야기 시킬 수 있다. 이 부식을 막기 위해 선박에서는 샤프트 그라운드 시스템을 설치하여 운용하고 있다. 이 축기전력을 측정은 프로펠러 축의 전압과 메인엔진의 회전수를 동시에 측정하였다. 측정장치는 내셔널인스트루먼트사의 24비트 A/D컨버터를 사용하여 측정하였고, 프로그램은 Lab View를 사용하였다. 본 논문은 축에 발생되는 기전력을 분석하였고, 분석결과를 이용하여 모델링을 하였다. 결과로 축기전력은 메인엔진의 회전수에 따라 비례하다가 일정회전수를 넘어가면 감소하는 경향을 보였다. 후진보다는 전진이 축기전력이 높은 결과를 얻었다. 전체기전력에 비하면 지구자기의 기전력은 미미하였다.

• Journal of Pharmaceutical Investigation
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• 제3권4호
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• pp.5-15
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• 1973

An investigation was carried out on a basis of the bacteriological examination with a view to detecting the degree of bacterial contamination for the 77 samples collected from the locally-sold liquid specialties. It's test period was 50 days from July 10 to August 30, 1971. Specially, the survey has put emphasis on the population of general bacteria and the identification of coli-form group, staphylococcus species, streptococcus species, bacillus species, fungi, and yeast species from liquid samples. The results obtained are summarized as follows; (1) For the 77 samples tested, the contamination of general bacteria was found out as minimun 0, i,e., maximum, $12{\times}10^4$ and the total average $45{\times}10^2$ per milliliter. (2) Although streptococcus species could not be detected with the samples, the contamination of the coli-form and staphylococcus species means the strong suggestion of the possibility of pathogenic bacterial contamination. (3) Specially, the products which stay in the neutral pH range and use suspending agents need to care for the microbial contamination in the manufacturing crocess. (4) It is thought necessary to perform the microbiological quality control in the liquid preparations only at least. (5) As the microbial contamination degree in the liquid decreases according to the elapse of time, the microbiological quality control will have to be carried out immediately after the completion of the manufacturing process in order to know the accurate degree. (6) The author thinks that the main reason of the microbial contamination in the liquid is the contamination during the manufacturing process. (7) For the purpose of prevention of the microbial contamination in liquid, therefore, it is more important to make efforts for the rationalization of manufacturing process, the improvement of equipment and environment, the specific training of workers for hygienic knowledges, etc. rather than the use of preservatives for the preparations.

• 한국식품영양학회지
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• 제31권2호
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• pp.284-292
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• 2018

This study was conducted to determine the elements that are required and that need improvement in the contents of dietary life education and the educational environment by analyzing the importance-satisfaction of a dietary life education program for dietary life education trainees. The results of the rank test for the satisfactory elements of dietary life education were in the order of competence of instructors, educational contents, time of education, educational environment and affordability of tuition. The importance-satisfaction analysis of the contents and construction of the dietary life education program showed that "suitable contents for the theme of the class", "contents and construction of practice class", "diversity of practice menu" and "diversity of educational contents" had high importance and satisfaction scores and therefore, could be maintained at their current levels. Meanwhile, "adequacy of class time" and "contents and construction of theory class" showed low importance and satisfaction scores, requiring a little effort. Whereas, "time and construction of group practice", "structure of textbook for class" and "duration of course and number of classes" showed relatively low satisfaction compared to importance, requiring major efforts for improvement. Similarly, analysis of the lecture element from dietary life education showed that "professional lecture by instructors", "lectures suitable for themes" and "lecture applicable in real life" had relatively low satisfaction compared to importance, requiring major efforts for improvement. In addition, analysis of the educational environment from dietary life education showed that "adequacy of lecture room space", "cooking equipment", "diversity of cooking utensils" and "sanitary condition of cooking utensils" also require major efforts for improvement. Therefore, dietary life education should not be executed with a simple delivery of knowledge but with both theory and practice classes to increase its application in real life, and active and specific efforts are required to nurture professional instructors and establish educational strategies.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2002년도 추계학술대회 발표 논문집
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• pp.100-111
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• 2002

The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle, four-cylinder, swirl chamber type, water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas recirculation(EGR) control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce $NO_x$ emissions. And a novel diesel soot-removal device of cylinder-type scrubber with five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection, however, would be included within those of scrubber EGR system. In order to survey the effect of intake mixture temperature on performance and exhaust emissions, the intake mixtures of fresh air and recirculated exhaust gas are heated by a heating device with five heating coils made of a steel drum. It is found that the specific fuel consumption rate is considerably elevated by the increase of intake mixture temperature, and that $NO_x$ emissions are markedly decreased as EGR rates are increased and intake mixture temperature is dropped, while soot emissions are increased with increasing EGR rates and intake mixture temperature. Thus one can conclude that the performance and exhaust emissions are considerably influenced by the cooled EGR.

• 융합보안논문지
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• 제9권4호
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• pp.7-12
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• 2009

DDoS 공격은 외부의 공격자가 일반 사용자들의 PC를 감염시킨 후 감염된 PC에서 특정 웹 사이트나 서버에 대량의 트래픽을 전송하여 리소스를 고갈시키거나 네트워크 대역폭을 점유함으로써 서비스를 마비시키는 공격으로, 완벽하게 막는 것이 대단히 어렵다. IDS(Intrusion Detection System：침입 탐지 시스템), IPS(Intrusion Prevention System：침입 방지 시스템), ITS(Intrusion Tolerance System), FW(Firewall) 또는 DDoS 전용 보안 장비 등을 이용하여 DDoS 공격을 막아내거나, 감내하려고 한다. 여러 종류의 보안 장비 비용 문제가 발생하기도 하고, 각 시스템 간의 연계성을 고려하지 않은 설치로 제 기능을 발휘하지 못하기도 한다. 본 논문에서는 DDoS 공격에 대한 보안 장비의 효과적인 연계와 대응 방법론을 제시한다. 설계된 방법론을 적용할 경우 기존의 네트워크 구조상에서보다 DDoS 공격에 대한 차단 및 감내 효율이 실험을 통해 입증되었다. 따라서 차별화된 DDoS 공격을 대응 및 감내하는 관제 방안을 본 연구를 통해 제시하고자 한다.

• 한국재난정보학회 논문집
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• 제13권4호
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• pp.550-561
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• 2017

본 논문에서는 한국의 119 상황 접수 요원들의 업무능력 향상을 위하여 업무와 교육방식의 문제점과 개선방안을 제시하였다. 먼저, 한국 및 미국의 응급전화 접수에 대한 매뉴얼과 교육 방법을 조사 및 비교분석 하였다. 조사내용을 바탕으로 경기도 119상황실 상황접수 요원 95명을 대상으로 설문조사를 실시하여 구체적인 개선방안을 검토하였다. 그 결과 119상황 접수와 관련된 인력 및 장비는 지속적으로 보완되고 있지만, 접수요원들에 대한 사전교육 등 훈련은 부족하여 실무에서는 요원들의 개인적인 경험과 역량에 의존하고 있는 실정이었다. 또한 업무에 비하여 전체적으로는 여전히 인력이 부족한 실정이었다. 따라서 119상황접수 요원에 대한 체계적인 교육 프로그램 마련 및 적정한 훈련과 테스트 기준 마련을 통한 상황접수요원의 전문성 강화, 대응 업무의 표준화 및 적정인력을 배치를 통하여 상황 판단의 오류 발생을 방지하고 업무를 체계화할 필요가 있는 것으로 검토 되었다.

• 한국실내디자인학회논문집
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• 제17권3호
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• pp.15-22
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• 2008

The purpose of this study is to propose evaluation factors for elementary school facility in terms of educational adequacy. The focal point of this study is to clarify the proper measure of educational facility evaluation in the light of specific characteristics of facility. In order to improve the level of educational adequacy, more information is needed regarding school facility design and various factors which affect to the design. This is important works because such information is essential in implementing facility design to meet the needs of the new educational policy. To get the goal, first, it is attempted to analyse the meaning of design information which deeply affect on the school facility design. The design information is classified into three main aspects, such as human aspect, social aspect and physical aspect. The design information regarding the physical space verses human psychology and behavior belongs to category of human aspect. Pedagogic ideology which varies depend upon the time and regions is classified into the category of social aspect. The Physical aspect means efficient equipment performance of space to support educational activities effectively. Secondly, as for the educational adequacy evaluation concern, it is attempted to select more items which usually has been neglected by the existing evaluation criteria which mainly emphasized functional performances only. With the premise of the above, in this paper, it is attempted to propose proper evaluation factors in terms of educational adequacy for school facilities. As the research methods, researching of literature on this subject, field trip, interview, site analysis, and survey is used.

• 한국군사과학기술학회지
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• 제22권5호
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• pp.599-606
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• 2019

The Arena Fragmentation Test(AFT) is one of the important tasks for designing a high-explosive warhead. In order to measure the statistics of a warhead in the test, fragments of a warhead that penetrate steel plates are detected by using complex and expensive measuring equipment. In this paper, instead of using specific hardware to measure the statistics of a warhead, we propose to use an image processing based object detection algorithm to detect fragments in AFT. To this end, we use a hard-thresholding method with a brightness feature and apply a morphology filter to remove noise components. We also propose a simple yet effective temporal filtering method to detect only the first penetrating fragments. We show that the performance of the proposed method is comparable to that of a hardware system under the same experimental conditions. Furthermore, the proposed method can produce better results in terms of finding exact positions of fragments.