• Journal of Environmental Science International
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• v.16 no.4
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• pp.449-458
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• 2007

Research results for the pressure drop variance depending on operation conditions such as change of inlet concentration, pulse interval, and face velocity, etc., in a pulse air jet-type bag filter show that while at $3kg/cm^2$ whose pulse pressure is low, it is good to make an pulse interval longer in order to form the first layer, it may not be applicable to industry because of a rapid increase in pressure. In addition, the change of inlet concentration contributes more to the increase of pressure drop than the pulse interval does. In order to reduce operation costs by minimizing filter drag of a filter bag at pulse pressure $5kg/cm^2$, the dust concentration should be minimized, and when the inlet dust loading is a lower concentration, the pulse interval in the operation should be less than 70 sec, but when inlet dust loading is a higher concentration, the pulse interval should be below 30 sec. In particular, in the case that inlet dust loading is a higher concentration, a high-pressure distribution is observed regardless of pulse pressure. This is because dust is accumulated continuously in the filter bag and makes it thicker as filtration time increases, and thus the pulse interval should be set to below 30 sec. If the equipment is operated at 1m/min of face velocity, while pressure drop is low, the bag filter becomes larger and thus, its economics are very low due to a large initial investment. Therefore, a face velocity of around 1.5 m/min is considered to be the optimal operation condition. At 1.5 m/min considered to be the most economical face velocity, if the pulse interval increases, since the amount of variation in filter drag is large, depending on the amount of inlet dust loading, the operation may be possible at a lower concentration when the pulse interval is 70 sec. However, for a higher concentration, either face velocity or pulse interval should be reduced.

• Journal of Korean Society of Forest Science
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• v.107 no.3
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• pp.316-323
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• 2018

This study was conducted with the intention of providing basic data that are essential for establishing compensation standards for forest products and diagnosing forestry management in the future by investigating the cultivation process of major wild edible greens such as Pteridium aquilinum var. latiusculum, Ligularia fischeri, and Allium victorialis and analyzing related incomes. According to the result, the cultivation was generally divided into the open filed cultivation and mountain cultivation by the cultivated item. The annual average income by unit area ($3.3m^2$) for each item was 6,500 won for Pteridium aquilinum var. latiusculum cultivated open filed, 3,200 won for Pteridium aquilinum var. latiusculum cultivated in the mountain, 20,400 won for Ligularia fischeri cultivated open filed, 20,900 won for Allium victorialis cultivated open filed, and 7,300 won for Allium victorialis cultivated in the mountain. Particularly, while consumer demand for Allium victorialis and Ligularia fischeri are increasing phenomenally recently, the annual average income per unit area ($3.3m^2$) for these wild edible greens grown open filed was distinctively higher than that for Pteridium aquilinum var. latiusculum. This can be explained by very high working expenses (land rent and labor cost) required for the cultivation of Pteridium aquilinum var. latiusculum compared with other items. As for Ligularia fischeri and Allium victorialis yielding high annual average income, the initial investment costs including the cost of purchasing seeds and seed stocks account for 40% of the working expenses or over and thereby requiring proper support from the government for solidifying the income source and promoting cultivation in the agricultural and mountain regions in the future.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.251-258
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• 2016

This article reports current status of micro fuel cell-combined heat and power (${\mu}FC$-CHP) systems which utilize both power and heat generated by fuel cells. There are several options for constructing CHP systems and among them, fuel cells are the most useful and their total energy efficiency combining heat and power can reach up to about 90%. Fuel cells are classified as five types based on the electrolyte, but the most suitable fuel cell types for the ${\mu}FC$-CHP system are proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs). ${\mu}FC$-CHP systems have several advantages such as decrease of the transmission-distribution loss, reduced costs of electricity due to distributed power generation, and environmental-friendliness owing to zero emission. The main drawback of the ${\mu}FC$-CHP systems is the high initial investment, however, it keeps decreasing as the technology development reduces production costs. Currently, Japan is the most leading country of the ${\mu}FC$-CHP market, however, Korea tries to expand the market by planning the deployment of 1 million units of ${\mu}FC$-CHP systems and governmental subsidiary supporting of half of the install price. In this report, integration technologies for connecting FC and CHP, and technology trends of leading countries are presented as well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.252-263
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• 2018

In this research, we performed a SWOT analysis to analyze the feasibility of cultivating tropical fruits in Korea, using the mango as a case study. The opportunities for domestic tropical fruit (mango) cultivation are that the domestic cultivation environment is improving due to global warming, the consumer market is expanding due to the increase in domestic demand, and some local governments are supporting the cultivation of tropical fruits as a new high-income crop. The strengths are that it is possible to produce high quality fresh fruits in Korea and that they are still distributed in small quantities, so they can be differentiated from imported ones. There are regular customers and the mango is recognized as a medicinally functional fruit. The threats are that the price competitiveness of imported goods is likely to be further strengthened due to the implementation of the FTA and that it is difficult to cope with the unpredictable climate changes, such as heavy snowfall and extremely cold weather. The weak points are that the initial investment cost is high, the operating costs such as heating bills are also very high, and there is no supply system for the chemicals, fertilizers and cultivation technology required for tropical fruits. In order for tropical fruits such as mangoes to become major fruits, we must make full use of these strengths and opportunities while, at the same time, complementing the weaknesses and eliminating the threats in the value chain.

• The KIPS Transactions:PartD
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• v.12D no.7 s.103
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• pp.947-956
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• 2005

Software(S/W) reengineering is one of the effective technologies to produce a business worth and en and the S/W ROI continuously. In spite of, S/W reengineering has been recognized a cost-consumptive works with inefficient productivity. In fact we have used to transform to confusion system with destructive system architecture by extending and updating legacy system in a temporary expedients. Moreover it is impossible to provide the time-market products for coping with rapid changeable system environment and meeting to complicated customer's requirements. Therefore, we need a systematic reengineering methodology to fulfill the changeable environment, as appearance of new IT techniques, various alteration of business information model, and increment of business logic. Legacy systems can be utilized as the core property in business organization through reengineering methodology. In this paper, we target to establish the reengineering process, proposed MaRMI-RE consisting of initial Planning phase, reverse engineering and component transformation phase. To describe the MaRMI-RE, we presented the concrete tasks and techniques and artifacts per individual phase in process, and the case study is showed briefly.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.753-757
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• 2014

Anode electrode in a microbial fuel cell (MFC) should transfer the receiving electron as well as provide large surface area that can be immobilized microorganisms. Microorganisms' population is one of important factors to improve the current generation and to treat the livestock wastewater by biological treatment. These studies were attempted to investigate if stainless-steel wire skein (SSWS) could be used as anode electrode replacement a graphite felt electrode in microbial fuel cell. For these studies, pretreated livestock wastewater was used diluted to 500 mg/L as COD before use. At this time, the current showed a little difference of about 5% when using each of a SSW and graphite felt (control). There was no significant difference in the current value. The organic removal rate in the microbial fuel cells used graphite felt and SSWS was 82.4% and 88.3%, respectively. The COD removal in the MFC used the SSWS was higher than that of graphite felt. Ammonium nitrogen was showed similar trend in two case all. These results about current generation and organic matter reduction seem possible that SSWS was used to anode electrode. When SSWS is used, the initial investment for system construction is expected to be able to reduce by approximately 1/50.

• Environmental and Resource Economics Review
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• v.16 no.2
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• pp.275-311
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• 2007

Hydrogen energy is emphasized as a substitutable energy of carbon-based energy system in the future, since it is non-depletable and clean energy. Long term vision of Korean government on the national energy system is to promote hydrogen energy by 15% of final energy demand until 2040. This study analyzes economic impacts of hydrogen energy development employing a dynamic CGE model for Korea. Frontier technology such as hydrogen energy is featured as slow diffusion at the initial stage due to the learning effect and energy complementarity. Without government intervention, hydrogen energy would be produced upto 6.5% of final energy demand until 2040. However, if government subsidizes sales price of hydrogen energy by 10%, 20%, and 30%, share of hydrogen energy would increase 9.2%, 15.2%, and 37.7% of final energy demand. This result shows that the slow diffusion problem of hydrogen energy as frontier technology could be figured out by market incentive policy. On the other hand, production levels of transportation sector would increase while growth rate of oil and electricity sectors would decline. Household consumption would be affected negatively since increase of consumption due to the price decrease would be overwhelmed by income reduction owing to the increase of tax. Overall, GDP would not decrease or increase significantly since total production, investment, and export would increase even if household consumption declines.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.139-152
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• 1985

본 NEWASA 지역의 접수관정관개 개발에 따른 정제성분석 연구는 IBRD-EDI와 INDIA RESERVE BANK의 College of Banking이 공동주최한 Trainers Trining for Rural Finance (1985. 1.19-3.1)의 일환으로 1985. 2. 14-19 까지 NEWASA BLOCK에 대한 정수정관개의 경제적 효율성을 평가하기 위하여 농가조사를 실시하였고, 그 분석결과를 정리한 것으로 농지는 넓으나 농업용수가 부족한 본 지역은 빈곤과 저생산성 농촌잠재 실업을 특징으로 하고 있다. 농촌소득의 제고와 농촌실업의 고용확대는 전 인구의 80% 이상이 농민인 본지역뿐만 아니라 선언도 경제개발의 중심과제이다. 호당 6 acres 규모의 관개가 가능한 Dug-well Irrigation Development는 연평균 강우량이 650m/m에 불과한 인도의 Plateau 지역에서는 농촌빈곤과 실업문제의 해결, 토지 이용율제고를 통한 토지생산성 향상등 농촌경제개발의 중심과제로서 인도정부가 추진하는 핵심적인 농업정책이다. 본 지역의 농가호당 평균 소유농지연적은 8.67 acres(3.5ha)로써 모두가 Rainfed farming으로 현재 본 지역의 관개율은 17.5%에 불과하다. 농작물은 Jowar라고 하는 내한성 작물이 재배되며, 관개 조건하에서는 Jowar, Wheat, Sugarcane이 재배된다. With and Without Dug-Well Irrigation 조건하에서 각 작물별 ha당 생산성을 보면 Jowar는 0.86 ton/ha에서 2.22 ton/ha으로 증산되고 Wheat는 2.96 ton/ha, Sugarcane는 98.8 ton/ha이 생산된다. 한편 Dug-well Irrigation 전후의 농가소득의 변화를 보면 시행전의 4,275Rs가 되어 4배의 농가소득이 증가된다. 이와 같은 농업소득을 획득하기 위해서는 Dug-well에 대한 Initial Investment로서 33,400Rs(2,137,600원)이 투자되어야 하는데 종류별 융자 기간을 보면 Dug-well 15년(95%융자) Pump Set 9년(95%융자), Woriking capital 1년이며 인도의 Union Bank에서 융자하고 있다. 결론적으로 이러한 Dug-well Irrigation Development에 따른 IRR는 Before Financing시에는 29%이며 After Financing 시에는 24%이고 B/C ratio는 두경우에 있어 1.89, 1.24를 각각 나타냈다. 따라서, 본 사업은 재무적인 측면 즉 농가소득증대와 농촌고용증대 및 토지이용면에서 타당성이 크며 Dug-well Irrigation은 인도의 농업성장 및 경제개발의 관건으로 생각된다. 한국의 수리개발 기술 및 농업기술(Bio-chemical, Mechanical & Hydrological Technology)이 이전된다면 보다 괄목할 만한 농업발전이 이룩될 것을 생각된다.

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.446-457
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• 2012

Recently, BIM(Building Information Modeling),which has been an issue in construction work, has been focused on as a new alternative of building industry for way out of crisis by slowing down and decreasing of orders in construction industry. Research for introducing BIM to the architectural field is already proceeding actively at home and abroad. However, civil engineering is so nonrecurring, horizontal, and different from regular construction works that it a large amount of information occurs because of wide range of project, which causes construction firms and design engineers to have some questions whether their initial investment cost would work or not and feel uncomfortable with the cost. In this study, technology level in engineering firms were surveyed for adapting BIM to domestic civil engineering. Development direction of BIM standard information model was drawn through awareness change analysis of BIM in civil engineering, as well. Deduced development direction is composed of guide development, system development, deliverable check and international standard proposal. The outcome will be employed as preliminary data for the study on development of infrastructure BIM standard and deliverable check system in civil engineering.

• Journal of the Korea Society for Simulation
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• v.24 no.1
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• pp.35-43
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• 2015

This research proposed a new method to evaluate the objective validity to launch smart transportation services that various stakeholders are complicatedly inter-connected. First of all, we have designed the fundamental business model to form the smart transportation services and defined the stakeholders taking part in the services. Also, the criteria to evaluate the economical validity has been proposed based on the relationship among stakeholders. Especially, in the case EV drivers and charging service providers, the economical validity depends on the scale of spreading. Therefore, we have compared the two extreme scenarios, the poor and stable level of EV spreading. According to the result, it may be said that EV drivers and charging service providers cannot be guaranteed the economical validity due to the burden of initial investment. On the contrary to this, suppliers of EV and charging gears may secure more than a certain level of profit. In addition, the government may have great profit due to reducing the CO2 emission and cost for importing energy sources. Therefore, it is needed to enhance the level of supporting EV drivers and charging service providers at the first stage. Also, the impact of the ratio of EV and charging service stations on the economical validity of smart transportation should be further investigated.