• 에너지공학
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• 제5권1호
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• pp.42-49
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• 1996

천연가스는 기존 내연기관의 구조를 크게 변경시키지 않고도 사용이 가능하며, 저공해성, 안전성, 내구성 등에 있어서 우수한 특성을 가지고 있고, 매장량이 풍부하다는 점에서 자동차용 대체연료로서 유망시 되고 있다. 본 연구에서는 기존 가솔린 기관을 CNG 전용기관으로 개조한 후, 공연비, 점화시기 등과 같은 기관 운전조건들을 최적화한 CNG전용기관을 기존 가솔린차량에 탑재하여, 샤시동력계상에서 연료소비량 및 배기배출물 농도를 측정·비교하였다. 또한, 실도로상에서 가속성, 운전성 등의 차량 주행특성에 대해서도 평가하였다. 그 결과, 시작 CNG차량의 경우에는 가솔린 차량에 비하여 연비는 향상되었고 배기배출물은 저감되었으나 출력은 약간 감소되었다.

• 한국식품영양과학회지
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• 제5권1호
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• pp.11-17
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• 1976

Put four different kinds of Jangdongsi, Pasi, Gamsi, and Taebongsi etc. into glass bottle(Fig. 1) of 1150ml and after modulated constitution of air girding this, by means of $CO_2$ the keep in cold storage on $0{\sim}5^{\circ}C$. The results are as follows : 1. $CO_2$ non-addition group was not changed it's own color to four months regardless of kind of persimmons 2. $CO_2$ added test group by double quantity of container was not more rapidly discoloration. 3. One - half quantity of test group added double, same, one-half and one of fifth quantity of container was the most effect, $CO_2$ as the same kind in S. T. P. 4. Taebongsi of test group of four different kinds added one-half quantity of $CO_2$ was maintained effectually possible it's natural color till seven months. 5. In taste, non-addition of $CO_2$ existed astringency taste but addition of $CO_2$ showed sweet taste like a Gamsi since two months of storage.

• 보존과학연구
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• 통권15호
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• pp.104-127
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• 1994

Traditional architecture has structural limits after some terms because it almost made by wood elements. So in the name of 'Restoration', by anatural process, repair works are accomplished. But the repair works of traditional buildings have some problems in spite of best men power and technology. To overcome this problems, we need more detailed studies for examine the reasons of destruction in elements of wooden buildings. The life limits of wooden buildings are caused by natural circumstances and humanic circumstances, the former has bad effect on the damage in wooden buildings. There are various elements of damage in the wooden buildings, earthquake, the falling of a thunderbolt, fire, and rain, microorganism, insect, and so on. Moreover pollutions-sulfurous acid gas, acidorganic matters -are important reason of shortening the life of wooden buildings. From 1981 till now we investigated important traditional buildings under repair works by the way scientific analysis to catch the sample - seramics, woods, insects, metals, etc. In this reports we suggest various method of investigation with two samples of tradional house made by wood, one is Kim Joo Tea House, the order is Simgum-dang of Magok-Sa(dwelling of monk).

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 가을 학술발표회 논문집
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• pp.24-31
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• 1997

Recently, in Korea, demand for establishment of systematic risk assessment techniques for construction projects has increased, especially after the large construction failures occurred during construction such as New Haengju Bridge construction projects, subway construction projects, gas explosion accidents etc. Most of existing risk analysis modeling techniques such as Event Tree Analysis and Fault Tree Analysis may not be available for realistic risk assessment of construction projects because it is very complex and difficult to estimate occurrence frequency and failure probability precisely due to a lack of data related to the various risks inherent in construction projects like natural disasters, financial and economic risks, political risks, environmental risks as well as design and construction-related risks. Therefor the main objective of this paper is to suggest systematic probabilistic risk assessment model and demonstrate an approach for probabilistic risk assessment using advanced Event Tree Analysis introducing Fuzzy set theory concepts. It may be stated that the Fuzzy Event Tree AnaIysis may be very usefu1 for the systematic and rational risk assessment for real constructions problems because the approach is able to effectively deal with all the related construction risks in terms of the linguistic variables that incorporate systematically expert's experiences and subjective judgement.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.107-110
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• 2013

Recently, Korea parliament legislated the Low Carbon Green Growth Act (April, 2012) and approved a bill (May, 2012) to start carbon emission trading system in 2015. It means that for the first time, government would regulate the amounts of carbon emission in private entities, and private entities should attain predefined emission reduction goals by implementing clean development mechanism (CDM) project or buy the Certified Emission Reductions (CERs) from the trading market to avoid penalty. Under these circumstances, it is not easy for them to determine when or how to implement the CDM project because the governmental energy policies about the level of governmental subsidies, periods for free emission allocation, etc. are still under discussion and the future price of the CERs is quite uncertain. Thus, this study presents a real-option based model to assess the financial viability of the CDM project which switches bunker-C oil to liquefied natural gas (LNG). The proposed model is expected to assist private entities in establishing the investment strategy for CDM project under uncertain government energy policies.

• Korean Chemical Engineering Research
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• 제58권4호
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• pp.573-580
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• 2020

최근 석유를 대체할 수송 에너지원으로 수소에 대한 관심이 커지고 있다. 수소의 장점을 극대화하기 위해서는 수소 충전소가 많이 보급되어야 한다. 본 논문은 수소 충전소를 보다 가깝게 이용 할 수 있는 최적 위치 선정 방법론을 제안하였다. 기존 에너지의 공급처인 주유소와 천연가스 충전소의 위치를 우선 참고하고, 인구, 등록 차량 수 등의 데이터를 추가 반영하여 수소자동차의 예상 충전 수요를 계산하였다. 기계 학습(machine learning) 기법 중 하나인 k-중심자 군집화(k-medoids Clustering)를 이용하여 예상 수요에 대응하는 최적 수소 충전소 위치를 계산하였다. 제안된 방법의 우수성은 서울의 사례를 통해 수치적으로 설명하였다. 본 방법론과 같은 데이터 기반 방법은 향후 수소의 보급 속도를 높여 환경친화적인 경제 체계를 구축하는데 기여할 수 있을 것이다.

• 한국수소및신에너지학회논문집
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• 제27권1호
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• pp.114-120
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• 2016

This paper describes generating efficiency characteristics of the double acting Stirling engine/generator for domestic small-scale CHP (Combined Heat and Power) system. In small distributed generation applications, Stirling engine has competition from fuel cell, microturbine and etc. In order to be economical in the applications, a long life with minimum maintenance is generally required. Free piston Stirling engine (FPSE) has no crank and rotating parts to generate lateral forces and require lubrication. Double acting Stirling engine/generator has one displacer and two power piston which are supported by flexure springs. Two power pistons oscillate with symmetric displacement and are connected with moving magnet type linear generators for power generation from PV work. In experiments, 1 kW class double acting free piston Stirling engine/generator is fabricated and tested. Heat is supplied to hot end of engine by the combustion of natural gas and converted to electric power by linear generators which are assembled with power pistons. The electric parameters such as voltage, current and phase are measured with for variable flow rate of fuel gas. Especially, generating efficiency of FPSE is measured with three different measurement methods. Generating efficiency of the double acting Stirling engine/alternator is about 24%.

• 전자공학회논문지
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• 제53권11호
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• pp.99-106
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• 2016

라돈이 기관지나 폐포에 머무르게 될 때 라돈의 붕괴로 인해 자핵종(알파선, 베타선, 감마선 등)들이 생성되면서 이것들이 방사선을 방출하는데 세포의 염색체에 돌연변이를 일으켜 폐암을 발생할 가능성이 존재한다. 다시 말해 폐암의 원인이 라돈가스 때문이라기보다는 흡수된 일부 라돈의 붕괴로 인해 생기는 부산물이 방사선을 방출하기 때문이라고 할 수 있다. 사람이 연간 노출되는 방사선의 82%가 자연방사선에 의한 것인데 그중 대부분이 라돈이다. 실내의 라돈 농도를 적절하게 제어할 수 있다면 폐암의 발생확률을 30%나 억제할 수 있다고 알려져 있다. 아직까지 실내의 라돈의 농도를 측정하는 데는 외국의 라돈 센서를 사용하고 있는 실정이다. 실내 라돈 방출량에 대한 데이터 구축과 국내에 맞는 실용적인 라돈측정기기를 개발하도록하는 연구가 필요하다. 본 논문에서는 PIN Photodiode를 이용하여 라돈의 농도를 측정하는 라돈 검출기 구현 방법을 제안한다. 실험을 통해서, PIN photodiode의 라돈 센서 모듈로서의 이용 가능성에 대하여 확인하였다.

• 설비공학논문집
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• 제19권1호
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• pp.94-131
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• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.

• 디자인학연구
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• 제19권4호
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• pp.175-186
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• 2006

21세기는 화석연료 자원의 고갈과 더불어 자동차의 배기가스로 인한 환경오염 문제의 심각성이 더욱 심화되어 화석연료를 대신할 수 있는 대체에너지 개발에 선진국을 비롯한 각 국에서 연구가 진행되고 있다. 제천은 주변에 많은 문화재 단지와 역사문화 유적지를 갖고 있다. 뿐만 아니라 다양한 문화 행사도 주최하고 있어 관광자원도 고루 갖추었다고 할 수 있다. 그러나 제천을 비롯하여 주변의 관광지들을 연계할 수 있는 교통수단이 미비하고 일반적이어서 특별한 교통수단을 개발할 경우 또 다른 관광자원으로서의 역할이 기대된다. 제천지역의 특성화를 위한 친환경운송수단 교통시스템의 설정을 위해 이론적 배경으로 제천지역의 특성을 조사하였다. 방향설정을 위해 기존의 성공적인 사례연구를 통해 교통시스템을 연구하였다. 또한 친환경 에너지원을 사용하는 운송수단인 태양열자동차, 연료전지자동차, 하이브리드 카, 전기자동차, 천연가스 자동차 등의 내용, 방식, 구조 및 장 단점 등을 연구 조사하였다. 연구조사를 바탕으로 제천지역에 적합한 친환경운송수단의 가능한 방향을 세 가지로 제안하였다. 제안된 안을 각 계 전문가들의 자문을 통해 비교 검토한 후 가장 적합한 교통시스템, 자동차 에너지원 및 차량형식, 승차인원과 차량제원 등을 결정하였다. 결정된 방향으로 자동차디자인 프로세스에 따라 디자인 안을 도출하고자 하였다. 제천과 주변지역을 연계하고 청정지역의 이미지를 살릴 수 있도록 친환경 에너지원을 사용하는 교통수단의 특별한 익스테리어디자인을 제천시청과 충북도청에 제안하므로 제천을 관광특성화 할 셔틀버스의 디자인비즈니스를 개발하고자 하였다.