• 동력기계공학회지
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• 제21권6호
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• pp.110-116
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• 2017

Recently the global warming caused by greenhouse gas has emerged as a global environmental problem. For this reason the continued efforts to reduce greenhouse gas emission by international cooperation and each country are in progress. Climate changing has been recognized as the world economy development from fossil fuel use is the culprit. The international maritime organization marine environment protection committee of the global warming reduction emerged restrictions on air pollution have been strengthened. Therefore, the author has investigated the effects of fuel temperature on the characteristics of combustion and performance, using an four-cycle, six cylinders and direct injection diesel engine. The results of cylinder pressure, rate of pressure rise, rate of heat release and specific fuel consumption were increased by changing of fuel temperature.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.63-64
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• 2011

Recently, due to global warming, CO₂ emissions is one of the global issues over all areas including construction industry. In Korea, apartment housing has large ratio of building construction and its CO₂ emissions during the operation and maintenance has the most large amount of tatal life cycle of apartment housing. However, there are rare research related to this subject. So, this study investigates the CO₂ emissions of domestic apartment housing during the operation and maintenance. In the future, the results of this study can be utilized in further study to decrease CO₂ emissions strategy.

• 무역상무연구
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• 제75권
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• pp.159-177
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• 2017

In this paper, we examined trends and regulations of the global medical equipment industry through literature search. The medical equipment industry is attracting attention as a new growth engine in the Fourth Industrial revolution. However, the medical device industry is a highly competitive field due to product diversity, short product life cycle and technological advances. In addition, Medical equipment are related to human health and safety. Therefore, it can only be exported if it is approved by national or international standards. Therefore, from the development stage of the product, the medical equipment should designate the country to be exported and develop a medical equipment that meets the requirements for licensing the medical equipment in the country. Therefore, In this paper, In this paper, we will present the practical considerations of the medical equipment exporting company by examining the global medical equipment market trends and the regulations related to medical equipment in major countries.

• 대한수학회지
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• 제50권4호
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• pp.695-713
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• 2013

We formulate and study a predator-prey model with non-monotonic functional response type and weak Allee effects on the prey, which extends the system studied by Ruan and Xiao in [Global analysis in a predator-prey system with nonmonotonic functional response, SIAM J. Appl. Math. 61 (2001), no. 4, 1445-1472] but containing an extra term describing weak Allee effects on the prey. We obtain the global dynamics of the model by combining the global qualitative and bifurcation analysis. Our bifurcation analysis of the model indicates that it exhibits numerous kinds of bifurcation phenomena, including the saddle-node bifurcation, the supercritical and the subcritical Hopf bifurcations, and the homoclinic bifurcation, as the values of parameters vary. In the generic case, the model has the bifurcation of cusp type of codimension 2 (i.e., Bogdanov-Takens bifurcation).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.219-222
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• 2009

Green ocean is one of the main issues internationally. Most governments are leading the role in boosting the economy through creating new green market and establishing system of coping with increasing international environmental regulation. Green ocean, which is a solution for the environmental issue of global warming, is applied throughout the industry. Domestic transportation industry including railway is also developing technology for creating green ocean. Transportation must decrease energy consumption at running stages because it shows high environmental loads expecially on using stages during its life cycle. Therefore, There are some tries for developing technologies; new engine through alternative energies, hybrid and lightweight. Railway transportation can not be exception. it is intended for this paper to suggest the direction of manufacturing environmentally friendly railway vehicle through the global warming effect evaluation of several materials being applied to vehicle and comparison of the results.

• 한국CDE학회논문집
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• 제19권3호
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• pp.245-252
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• 2014

Engineering applications of global optimization techniques are recently abundant in the literature and it may be caused by both new methodologies arising and faster computers coming out. Many of the optimization techniques are based on natural or biological phenomena. This study put focus on enhancing the performace of Cuckoo Search (CS) among them since it has the least number of parameters to tune. The proposed enhancement can be achieved by applying surrogate-based optimization at every cycle of CS, which fortifies the exploitation capability of the original method. The enhanced algorithm has been applied several engineering design problems with constraints. The proposed method shows comparable or superior performance to the original method.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2005년도 학술발표대회 논문집
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• pp.385-392
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• 2005

The restriction of the use of hazardous substances in electrical and electronic equipment legislation mandates the substitution of lead and other hazardous substances in electronics products by July 2006. Due to this legislative pressure, the electronics industry is moving to adoption of lead free solders. In this paper, we investigated a flux to restrict generating electrochemical migration in lead-free solder. The lead-free solders used in this study were Sn-0.7Cu-0.01P and Sn-3.0Ag-0.5Cu. To measure the resistance of electrochemical migration, the dew-cycle test and water drop test were adopted. As the result, now flux having high durable of electrochemical migration was developed.

• 생태와환경
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• 제43권4호
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• pp.453-458
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• 2010

DOC (Dissolved Organic Carbon) is an operational terminology for organic carbon molecules dissolved in natural waters. DOC has been studied by ecologists extensively, because it plays a key role in various ecological functions such as substrates for secondary production and the carbon cycle. DOC also represents a substrate for microbial growth within potable water distribution systems, and can react with disinfectants (e.g., chloride) to form harmful disinfection by-products. In addition, residual DOC may carry with it organically bound toxic heavy metals. DOC in aquatic ecosystems may ultimately be transported to the oceans, or released back to the atmosphere by heterotrophic respiration, which can accelerate global climate change. There is evidence that DOC concentrations in aquatic ecosystems are increasing in many regions of the world including Europe, North America, and even in Korea. Land use changes, elevated temperature, elevated $CO_2$, recovery from acidification, and nitrogen deposition have been proposed as mechanisms for the trend. However, the key driving mechanism is yet to be conclusively determined. We propose that more extensive and longer-term observations, research of chemical properties of DOC, impacts of elevated DOC on environmental issues and interdisciplinary approaches are warranted as future studies to fill the gaps in our knowledge about DOC dynamics.

• Architectural research
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• 제3권1호
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• pp.29-36
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• 2001

Concern about global environment has been increasing in recent years. Efforts to minimize the environmental impact to the globe as well as human beings have increased, especially in the late twentieth century. The study researches one of the solutions for the environmentally friendly building construction, which can contribute to sustaining the world environment. Assessment and proposals are made for high-rise apartments, one of the most popular construction types nowadays in Korea. Since the volume of high-rise apartment construction is so great, a small improvement in each building will make a great contribution. Assessments are made over the life-span of apartment buildings. A tool named EIAHA (Environmental Impact Assessment for High-rise Apartment) has been made through references from western examples, mainly in the UK. The components of EIAHA include passive design strategies, building materials, energy consumption during building operation and management/maintenance. Although the issues are on a global scale, solutions are sought on regional scale. Korean high-rise apartments are assessed with the tool and suggestions for sustainable development are made mainly for improvement of embodied energy of building materials and the life of buildings.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.365-370
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• 2009

LCA is a tool to support for making decisions by offering information of environmental aspects of products or services. It can be used to make decisions to consumers and NGOs as well as government and enterprises. LCA evaluates the environmental aspects throughout the entire life cycle of a product. Therefore it can quantify and assess environmental impacts from raw material acquisition, manufacturing, distribution, use and disposal to end of life and recycling. The demands of the recycling rate increase and the use of suitable materials for RoHS, REACH, WEEE, ELV which are linked trade with environmental regulation have increased the worldwide. Global warming is the critical challenge of the world facing. And under post-Kyoto protocol each country has to prepare for target reduction, so it became essential to save energy and resources. In addition that, the carbon mark has been run as the way of showing example of CO2 reduction in domestic and it will be extended gradually. And also through the introduction of Eco-label, environmentally-friendly product will be promoted. When those systems are operated, global warming gases (i.e. CO2) can be calculated throughout the entire life of the products by LCA. And the environmental impacts such as harmful material emission in the process of manufacturing, energy consumption, distribution and so on, can also be assessed. Therefore, The basic concepts of LCA technique and various cases and the practical application in the future will be review in this study.