• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.7
• /
• pp.258-264
• /
• 2018

This paper presents application of a differential search (DS) meta-heuristic optimization algorithm for optimal operation of a micro grid system. The DS algorithm simulates the Brownian-like random-walk movement used by an organism to migrate. The micro grid system consists of a wind turbine, a diesel generator, a fuel cell, and a photovoltaic system. The wind turbine generator is modeled by considering the characteristics of variable output. Optimization is aimed at minimizing the cost function of the system, including fuel costs and maximizing fuel efficiency to generate electric power. The simulation was applied to a micro grid system only. This study applies the DS algorithm with excellence and efficiency in terms of coding simplicity, fast convergence speed, and accuracy in the optimal operation of micro grids based on renewable energy resources, and we compared its optimum value to other algorithms to prove its superiority.

• Journal of the Korean Institute of Gas
• /
• v.18 no.2
• /
• pp.16-20
• /
• 2014

In this paper, the performance of pressure-resistance is validated by experiment on LPG re-fillable cylinder which has increased demands for spreading of camp culture. Propane has increased suppliable requirements as fuel because of easily vaporizing effect of low boiling point. However, propane can be occurring safety problems inevitably by high vapor pressure. So, the priority is that safe cylinder should furnish in order to be circulated as safe fuel. LPG re-fillable cylinder for high pressure is tried to furnish internationally, that is restricted by safe issues. For these reasons, the pressurization and rupture are performed by using pressurizing device that is operated by hydraulic system. Also, this paper will offer rupturable characteristics comparing with vapor pressure of propane. This paper is expected as basis research for developing re-fillable cylinder and using standard for supplying them.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.2
• /
• pp.395-400
• /
• 2017

The paper discussed the air-to-fuel ratio control of automotive fuel-injection systems using the cerebellar model articulation controller(CMAC) neural network. Because of the internal combustion engines and fuel-injection's dynamics is extremely nonlinear, it leads to the discontinuous of the fuel-injection and the traditional method of control based on table look up has the question of control accuracy low. The advantages about CMAC neural network are distributed storage information, parallel processing information, self-organizing and self-educated function. The unique structure of CMAC neural network and the processing method lets it have extensive application. In addition, by analyzing the output characteristics of oxygen sensor, calculating the rate of fuel-injection to maintain the air-to-fuel ratio. The CMAC may easily compensate for time delay. Experimental results proved that the way is more good than traditional for petrol control and the CMAC fuel-injection controller can keep ideal mixing ratio (A/F) for engine at any working conditions. The performance of power and economy is evidently improved.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.2
• /
• pp.66.2-66.2
• /
• 2019

구술채록은 특정 주제의 연구사 기록화 작업에 있어 후대에 생생한 역사체험을 전승할 수 있는 최적의 연구사업이다. 특히 국내 천문우주과학 분야의 원로들이 대부분 연로하다는 점에서 한국천문학 발전사에 대한 구술채록은 시급성이 더욱 요구되고 있다. 이에 한국천문연구원 고천문연구센터는 그간 기관에서 자체적으로 수행해 온 사료분류체계 수립작업과 단발적인 구술채록 경험을 기반으로 본격적인 구술채록 연구사업을 수행할 계획이다. 이 연구는 한국천문학 발전사 구술채록 사업의 절차적 방법에 대한 기획론이다. 크게 (1)구술채록 로드맵 수립, (2) 구술기록 생산 프로세스, (3) 산출물 관리 및 활용으로 제시하고자 한다. 먼저 구술채록 로드맵 수립에 있어서는 현대 한국천문학 발전의 태동기 1950년대 중반을 기점으로 역사연구 및 주제분류를 중심으로 천문학 구술기록 특성화를 기한다. 이를 기반으로 구술대상자를 선정하고 큰 맥락의 역사와 개인 생애사를 교차하는 분석 틀을 중심으로 인터뷰 질문지를 추출한다. 이 과정에서 구술대상자의 소장 사료를 도출하여 미리 잠재적 사료 수집을 도모하도록 한다. 둘째, 본격적 구술기록 생산 프로세스에서는 전 단계에서 이행한 수집정보를 바탕으로 구술 산출물을 제작한다. 면담일지, 상세녹취록, 요약본, 이용동의서 등 기타 필요한 구술 제반 서식을 바탕으로 구술 동영상을 산출하고 라벨링한다. 이 산출물에 대한 사실관계 검증 후 최종 산출물 완성 및 기타 행정 처리로 제작은 종료된다. 마지막으로 산출물 관리 및 활용에 있어서는 사료 수집 전략의 기반 자료와 다양한 지식정보콘텐츠의 활용체계를 수립한다. 더 나아가 향후 이 연구사업은 구술DB화와 서비스 체계화를 위하여 구술아카이브 시스템을 설계하는 데 성과물을 활용한다. 이 연구기획론은 한국천문학이라는 특정 주제에 대한 것이므로 큰 틀에서의 방법은 기록학적 전개방식을 차용하지만, 역사연구와 기록의 특성화에 있어서는 한국천문학 연구사에 대한 깊은 이해가 동반되어야 한다. 따라서 광범위한 한국천문학 네트워크에 해당하는 다양한 학회, 교육기관, 연구기관 및 각종 사단법인 등의 역사와도 긴밀히 연결되어야 성과물은 비로소 가치 있고 풍부할 것이다. 이 연구를 시발점으로 향후 한국천문학 발전사 구술채록 사업에 대한 다양한 관학연구의 인식 공감대가 마련되기를 기대한다.

• Journal of Energy Engineering
• /
• v.8 no.1
• /
• pp.189-201
• /
• 1999

범용 열가소성 플라스틱(polyethylene(PE), polypropylene(PP), polystyrene(PS), polyethylene-terephthalate(PET), acrylonitrile-butandiene-styrene(ABS))과 폐윤활유의 동시처리 열분해반응 실험을 수행하였다. 반응실험은 40$m\ell$ 용량의 회분식 미분반응기(microreactor)를 이용한 실험과 1리터 용량의 autoclave를 이용한 실험의 두 가지로 구분하여 행하였다. 전자의 경우는 통계적 실험적계획법(statistical experimental design)의 하나인 회전계획실험(rotatable design experiments)으로서 오각형 실험계획(pentagonal experimental design)에 의거한 반응변수 실험을 수행한 후 반응표면(response surface)을 회기분석법에 의하여 분석함으로써 최대의 오일 수율을 얻을 수 있는 최적 반응조건을 추적, 결정하였다. Autoclave 반응실험의 기본적인 목적은 실제 연속공정에 있어서 열분해 반응기 거동을 모사하기 위한 전초단계로서 충분한 시료의 확보를 통하여 이 때 생성된 연로유의 체계적인 분석(비등점분포특성, 진공증류, 기체분석, 원소분석, 발열량, 비중 등)을 행함으로써 연료유 수율 및 품질을 모사하고자 하였다. 미분반응기 실험에 있어서 주 범용열가소성수지인 PE, PP 그리고 PS는 각각의 최적반응조건하에서 거의 100%에 가깝게 오일로 전환되었지만 응축수지인 PET와 그래프트공중합수지인 ABS의 오일수율은 각기 78% 및 90%로서 상대적으로 낮게 나타났다. Autoclave를 이용한 실험의 경우 혼합플라스틱을 폐유에 대하여 40wt% 혼합하여 열분해하였을 때, 80wt% 오일, 15wt% 코우크, 그리고 나머지 5wt%는 탄화수소기체(C1-C6)로 전환되었다. 진공증류(252$^{\circ}C$,2 torr) 결과, 기/액-분리도는 3으로서 이는 생성오일의 75wt%가 경질연료유(가솔린, 등유, 경유)로 회수 가능하였다.

• Journal of the Korean Ceramic Society
• /
• v.39 no.12
• /
• pp.1164-1170
• /
• 2002

The effect of fly ash addition to the kaolin block has been investigated. The addition affected the firing temperature and physical properties such as water absorption and compressive strength. The starting materials were from korea natural resources and the fly ash were from the power plant using coal as fuel, containing free carbon of 8∼9 wt%. The starting natural materials were mixed with 5 different proportions of fly ash, pressed and then sintered at 1050, 1100, 1150 and 1200${\circ}C$. With sintering temperature, water absorption decreased and compressive strength increased. When specimens were sintered at the temperature lower than 1100${\circ}C$, water absorption increased and strength decreased with fly ash content. In contrast, when sintering was done at the temperature higher than 1150${\circ}C$, water absorption increased with fly ash content similarly but strength was improved.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.6
• /
• pp.781-787
• /
• 2014

The dimensionless extinction constants of particulate matter for F-76 diesel and JP-8 aviation fuels were measured at both 633 nm and 853 nm in the transmission cell where the simultaneous gravimetric measurement of PM concentration is compared to the light extinction measurement. For the F-76 diesel PM, the average value of the dimensionless extinction constants at 633 nm was 8.8 whereas that of the dimensionless extinction constants for JP-8 was 9.8 at the same wavelength. As the wavelength is increased to 853 nm, the average value for the F-76 diesel was reduced to 8.2 whereas that for JP-8 was decreased to 8.9.

• Journal of Ginseng Culture
• /
• v.1
• /
• pp.78-92
• /
• 2019

Among the Southeast Asian countries, Vietnam had the most cultural exchange with Korea. Through Confusion and Chinese character, which were the common measure for two countries, Korea and Vietnam could communicate and share a sentiment with each other. Two countries showed an enormous interest in each other, and hence they could keep good relationship without official diplomatic relations. During the early 19th century, Korean Ginseng had gained tremendous popularity in Vietnam. Vietnamese believed the stamina of Minh Mang, who had 142 sons and daughters, originated from ginseng. Minh Mang bestowed ginseng on old courtiers for their contribution, which made them more loyal to the king. This tradition was inherited to the future generations, and soldiers who fought with Thai, Cambodia and France also received ginseng for their contribution. In other words, ginseng was the very important key for enforcement of patriotism. Due to the tradition, Korean ginseng has been considered as the premium ginseng in Vietnam. It is presumed that ginseng flew into Vietnam through 4 routes; 1) as an imperial gift from Chinese emperor, 2) by the Vietnamese ambassadors who went to Beijing for a tribute, 3) through private trade and 4) from Ryukyu or Japan, which were the hub of international trade. From 15th to 18th century, ambassadors from Chosun and Vietnam actively interacted in Beijing. Through their interchange, Vietnamese royal family could learn about the value of ginseng. The fact that there were many Shilhak scholars among the ambassadors from Joseon, such as Seo Geojeong and Seo Hosu who had profound knowledge of ginseng proves the theory. It is also possible that reputation of ginseng was already established in Vietnam during Silla period. Ko Byung, an bureaucrat from Tang Dynasty who ruled Vietnam for 10 years in middle 9th century and a friend of Choi Chiwon, might have delivered the knowledge of ginseng to the upper class in Vietnam. This hypothesis, however, should be proven by literatures. Hence, further research about the trace of Korean ginseng in Vietnamese history and literary works still remains to be done.