• New & Renewable Energy
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• v.5 no.2
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• pp.15-24
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• 2009

As new small scale LFG (landfill gas) energy project model which can improve economic feasibility limited due to the economy of scale, LFG-Microturbine combined heat and power system with $CO_2$ fertilization into greenhouses was proposed and investigated including basic design process prior to the system installation at Gwang-ju metro sanitary landfill. The system features $CH_4$ enrichment for stable microturbine operation, reduction of compressor power consumption and low CO emission, and $CO_2$ supplement into greenhouse for enhancement plant growth. From many other researches, high $CO_2$ concentration was found to enhance $CO_2$ assimilation (also known as photosynthesis reaction) which converts $CO_2$ and $H_2O$ to sugar using light energy. For small scale landfills which produce LFG under $3\;m^3$/min, among currently available prime movers, microturbine is the most suitable power generation system and its low electric efficiency can be improved with heat recovery. Besides, since its exhaust gas contains very low level of harmful contaminants to plant growth such as NOx, CO and SOx, microturbine exhaust gas is a suitable and economically advantageous $CO_2$ source for $CO_2$ fertilization in greenhouse. The LFG-Microturbine combined heat and power generation system with $CO_2$ fertilization into greenhouse gas to enhance plant growth is technologically and economically feasible and improves economical feasibility compared to other small scale LFG energy project model.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.2 s.21
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• pp.37-44
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• 2006

Any vehicle and equipment whose total weight is more than 40ton and its axle weight is 10ton or above is banned to cross any bridge in our country under section 54 in the Highway law. This restriction results from the accumulation and application of safety factors about which there is type specification in the "standard design vehicle". And in "standard design vehicle", Vehicle load to bridge is assumed concentrating one. Based on this restriction, there is an issue that military tank which has a total weight of 51ton (63ton in case of the US tank) can not cross any bridge. However, many research and practical examples concerned manifest that it is possible for military tanks to cross these bridges. The reasons of this issue in the current Highway law's provisions are analyzed in this paper. Correspondingly, feasibility of military tanks passing these bridges are discussed here. At last, considering economical efficiency and practicability for military, several suggestions and improving measures are put forward. This research has certain reality significance to guide bridge design considering the passage of military heavy vehicles.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.5
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• pp.33-47
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• 2019

The environmental ecological flow (EEF) of stream or river will be designated according to the enforcement of the Water Environment Preservation Act. Previous researches by Ministry of Environment have proposed agricultural reservoirs as alternative resources to secure river flow where multi-purpose dam does not exist. However, agricultural reservoirs are constructed for the supply of agricultural water, and in fact, there is not a sufficient amount of water to be supplied to rivers as EEF. Therefore, this study examines the economic feasibility of securing EEF through the remodeling or construction of agricultural reservoirs. We investigated water balance of reservoir through simulation of three types of water supply demands such as agricultural water, agricultural water and river maintenance flow, and agricultural water and environmental ecology flow. The economics analysis was conducted on water supply demands and corresponding remodeling or construction of reservoirs. As a result, it was found that the method of securing through heightening existing reservoir enhancement is economically feasible. However, it was not possible to secure all the amount of the EEF due to the size limitation of existing reservoirs or constrain of the watershed for newly built reservoir. Therefore, in order to secure all of the EEF, the utilization of other alternatives as well as agricultural reservoirs should be considered. This study demonstrated the method of economical feasibility study of securing river maintenace flow and EEF using agricultural reservoirs and other considerations.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.11a
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• pp.278-283
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• 2009

Nowadays as public rental apartment increasing, a new national policy for the public rental apartment maintenance is needed. The co-op housing system can be considered as one of the solutions for that needs, as our socio-economical environment changes. This research is on development of the co-op housing maintenance system. The feasibility of the co-op housing maintenance system has been analysed, and an preliminary UML model for the system has been proposed. Research focus is on how the model can be well established from the analysis of a questionnaire survey.

• Journal of Welding and Joining
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• v.21 no.4
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• pp.31-38
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• 2003

Line heating is an effective and economical process for forming flat metal plates into three-dimensional shapes for plating of ships. Because the nature of the line heating process is a transient thermal process, followed by a thermo elastic plastic stress field, predicting deformed shapes of plate is very difficult and complex problem. In this paper, neural network model o3r solving the inverse problem of metal forming is proposed. The backpropagation neural network systems for determining line-heating positions from object shape of plate are reported in this paper. Two cases of the network are constructed-the first case has 18 lines which have different positions and directions and the second case has 10 parallel heating lines. The input data are vertical displacements of plate and the output data are selected heating lines. The train sets of neural network are obtained by using an analytical solution that predicts plate deformations in line heating process. This method shows the feasibility that the neural network can be used to determine the heating-line positions in line heating process.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.15 no.3
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• pp.105-111
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• 2009

In this work, source reduction of poly ethylene terephthalate (PET) packaging are discussed as aspect of sustainability, such as reuse, refill and recycling through the various treatment methods and historical studies for municipal solid waste (MSW) disposal. Since PET has good chemical, physical and mechanical properties, and provides good oxygen and carbon dioxide barrier properties, PET is one of the most widely used thermoplastic polyester in the U.S. and around the world. As the demand for non-renewable PET is increasing, several approaches have been developed to meet economical feasibility and environmental responsibility without degrading material performance. Several companies, such as Coca-Cola Co., Easterform Packaging Co. and Kraft, have tried to develop lightweight PET bottle, and some of lightweight PET bottles are already commercialized. Reuse and refilling for PET container is well developed in Europe, such as Denmark, German and Netherland by supportive legislation and policies. Recycling process is the best way to economically reduce PET waste. In consequence, advanced technique and further development must be provided due to increasing PET packaging waste.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.117-121
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• 2006

Generally, micro-stereolithography technology uses laser and complex optical system as light source and light delivery system, respectively. In this research, a novel micro-stereolithography technology that uses UV lamp that is more economical than UV laser as light source and optical fiber that is simpler than previous light delivery system has been developed. Furthermore, precise control system that is composed of 3-axis linear stage and shutter has been used to fabricate truly three dimensional micro-structure. For confirming the feasibility of developed micro-stereolithography apparatus, the solidification experiments were conducted. The solidification widths and depths datum of photopolymer as varying scanning speed of the UV light have been obtained. Using developed apparatus, some micro structures were fabricated successfully.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.821-824
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• 2009

LFG-MGT CHP system development project with $CO_2$ enrichment in greenhouses was introduced. LFG is produced from the anaerobic digestion of landfilled waste and it has been utilized for power/heat generation since it contains around 50% of $CH_4$. Utilization of LFG from small scale landfill is also needed as well as large scale landfill. However, due to economy of scale, it is very difficult to develop business model. In this context, combining CHP system with greenhouses is considered as feasible option for LFG utilization. LFG-MGT CHP system with $CO_2$ fixation in greenhouses has been derived as an active greenhouse gas reduction strategy, The focus of the system is beyond carbon neutral LFG utilization to neutral carbon absorption. The system is feasible in terms of direct and indirect $CO_2$ emission reduction with more economical way.

• Satellite Communications and Space Industry
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• v.13 no.1 s.28
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• pp.118-124
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• 2006

HAPS(High Altitude Platform Station) which is defined as a station located on an object at an altitude of 20 to 50 km and at a specified, nominal, fixed point relative to the earth is promising technology capable of providing broadband multimedia services. In this study, economical aspects of HAPS service are analyzed by estimating the revenue and costs incurred by the service. To evaluate the profitability of HAPS service, the number of subscribers is estimated and then the net present value (NPV), payback period, and the rate of return on investment (ROI) are calculated under various scenarios

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.38-39
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• 2006

KEPCO is executing a project in Cambodia consisting of two components, "Power Development Master Plan and Institutional Strengthening" and "Greater Mekong Sub-region (GMS) Power Project Preparation" upon request by the government of the Ministry of Industry, Mines and Energy of Cambodia, contracted on $29^{th}$ September 2005. This paper includes a basic design and review of economical efficiency for constructing the two (2) cross border 115 kV transmission lines, which run from the border of Vietnam and Laos to Cambodia, and four (4) 115kV substations. The main contents of the paper include the process of design and results of a review of line route selection, tower and hardware design regarding transmission line design, as well as the type of substation, and arrangement and specifications of equipment with expects to substation design. Also, long-term demand forecasting, and an economic analysis of the project area are included.