• Journal of Energy Engineering
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• v.13 no.4
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• pp.296-300
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• 2004

Performance evaluation and economic estimation were conducted on the water to water GSHP (Ground Source Heat Pump) installed in existing building. Ground heat exchanger was a closed vertical loop type and sized to be 5 boreholes and 100m depth per borehole. Operation efficiency of the system shows that, COP increased from 3.0 to 4.2 with entering water temperature in heating operation, however, COP decreased from 5.0 to 3.7 in cooling operation. Economic estimation was analyzed by LCC (Life Cycle Cost) method and it showed that GSHP could save 68% of cost compare to the conventional oil source. Thus, despite of the large amount of initial cost, GSHP has a economic advantage to the other energy sources.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.4
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• pp.153-161
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• 2020

This study investigates the recycling potential of demolition waste (DW) according to building structure, while considering economic aspects. For that, this study surveyed 1,034 residential buildings to collect reliable information on demolition waste generation rates (DWGRs). This study suggested a method for operational cost calculation for each stage and carried out an inventory analysis. The economic value of recycled DW materials was also calculated. And then, the recycling potential(RP) was calculated by building structures and waste types. RP by building structure was low (27-40%), and RP was found in the order of masonry-block, wooden, RC and concrete-brick. By type of DWs, the RP of aggregates was considerably lower than 7%, and DWs such as wood, plastics, and metals showed more than 100% RP. Considering the results of this study, In order to improve the RP of buildings and DWs, the diversification of products that recycled waste like aggregates (i.e., mortar, concrete, bricks, blocks, tiles) and the development of high value-added products are considered to be the most urgent problems. Based on the above RP results, this study proposed a more advanced method for life cycle assessment of buildings and demolition waste.

• Journal of the Korean Regional Science Association
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• v.40 no.1
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• pp.53-67
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• 2024

Regional migration is a problem faced by all non-metropolitan areas in Korea, but the extent of migration varies depending on regional economic conditions. This study examines how the extent of youth migration varies depending on the economic conditions of their birthplaces. The results showed that youth migration was more severe in areas suffering from population decline and aging problems. The smaller the economy and the weaker the financial independence of the region, the more severe the youth migration. In particular, commercial, educational, and cultural facilities, except for medical facilities, were not able to curb youth migration. In addition, there was a significant wage gap between those employed in the metropolitan area and those employed in the regions, regardless of their origin. This suggests that non-metropolitan areas are caught in a vicious cycle of regional economic deterioration and youth migration.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1610-1616
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• 2013

Recently, district heating and cooling (DHC) systems based on combined cycle generation (CCG) providers are increasing in Korea. Since characteristics of combined heat and power (CHP) generators and heat demands of providers, heat trading between DHC providers based on the economic viewpoint is required; the heat trading has been doing. In this paper, a mathematical model for optimal operation based on heat trading between DHC providers is proposed. Especially, start-up characteristic of CCG is included. The operation model is established by mixed integer linear programming (MILP).

• KDI Journal of Economic Policy
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• v.39 no.3
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• pp.43-62
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• 2017

This paper proposes an integrated risk-management framework that includes 1) measuring the risk of credit portfolios, 2) implementing a (macro) stress test, and 3) setting risk limits using the estimated systematic latent factor specific to capture the housing market cycle. To this end, we extract information from a set of real-estate market variables based on the FAVAR methodology proposed by Bernanke, Boivin and Eliasz (2005). Then, we show the method by which the estimated systematic factor is applied to risk management in the housing market in an integrated manner within the Vasicek one-factor credit model. The proposed methodology is well fitted to analyze the risk of slow-moving and low-defaultable forms of capital, such as alternative investments.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.80-86
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• 2011

This study compared and analyzed manual tapping and automatic tapping regarding tapping process characteristics of titanium hard-to-cut-material. Tapping process characteristics of titanium hard-to-cut-material are evaluated as the quality of a screw, wear of a tap, economic analysis, and cycle time etc. The type of screw threads after manual tapping is formed as an irregular type of screw threads, and perfect screw threads are created after automatic tapping. In addition, the chip type after manual tapping process is formed as the discontinuous chip due to work hardening, and the powder type of chip after automatic tapping process is created. In terms of cycle time, an automatic tapping process is shortened by 70% compared to manual tapping process. Insert tip wear of an automatic tapping shown in the process of 5-hole tapping is not found, but hand tap wear for finish cutting is most severe.

• Journal of the Korean housing association
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• v.14 no.5
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• pp.65-74
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• 2003

Recently, the environmental conservation has been emphasized over the world. Building industry should carefully reflected the development focused on the economic aspect as well as the environmental considerations. Therefore, it requires the technology development to mitigate the environmental pollution through the reducement of the energy and resources usage amount over the building life cycle. For these, it should be required to set up the analysis methodology to grasp the amount of the environmental pollution and energy and resources in each step of building life cycle. In this paper, it aimed at preparing the analysis process and analyzing the embodied energy and $CO_2$ and $SO_x$ emission according to the building work, field work, mechanical and electrical work on the new building and remodelling, utilizing the inventory analysis which is one of the LCA process.

• Korean Management Science Review
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• v.19 no.1
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• pp.179-188
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• 2002

Ventures through technological innovation are increasingly suggested as one of the main engines for economic growth that can help control inflation and black trade balance. The Purpose of this study is to extract the network performance factors for ventures according to ventures life cycle. For the Purpose, the existing studies were examined into start-up company, entrepreneurial firm, smell firms with competitive advantage against large firms, and ventures network activity. And 63 samples from ventures in Korea were taken and analyzed empirically. The analyses and results are (1) the actual conditions of network activity on ventures; (2) the investigation of relationship between network activity and performance of ventures by venture's life cycle through the observations of Korean ventures. From the results, It Is also found that factors such as external environment and a ventures life cycle have been considered as the main influences on the performance of ventures. In addition, limitations and suggestions for further studies are noted.

• Computational Structural Engineering : An International Journal
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• v.2 no.1
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• pp.11-17
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• 2002

Cost-effectiveness in design is considered for determining the target reliability of concrete bridges under seismic actions. This objective can be achieved based on the economic optimization of the expected life-cycle cost of a bridge, which includes initial cost, direct losses, and indirect losses of a bridge due to strong earthquakes over its lifetime. A separating factor is defined to consider the redundancy of a transportation network. The Park-Ang damage model is employed to define the damage of a bridge under seismic action, and a Monte Carlo method based on the DRAIN-2DX program is developed to assess the failure probability of a bridge. The results for an example bridge analyzed in this paper show that the optimal target failure probability depends on the traffic volume carried by the bridge and is between 1.0×10/sup -3/ to 3.0×10/sup -3/ over a life of 50 years.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.249-256
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• 1999

This study is intended to propose a systematic procedure for the development of the reliability-based seismic safety and cost-effective Performance criteria for design and upgrading of long span PC bridges. In the paper, a set of cost function models for life cycle cost analysis of bridges is proposed. The total life cycle cost functions consist of initial cost and direct/indirect damage costs considering repair/replacement costs, human losses and property damage costs, road user costs, and indirect regional economic losses. The damage costs are successfully expressed in terms of Park-Ang median global damage indices and damage probabilities. The proposed approach is successfully applied to model bridges in both regions of a moderate seismicity area like Seoul, Korea and a high one like Tokyo, Japan. It may be expected that the proposed approach can be effectively utilized for the development of cost-effective performance criteria for design and upgrading of various types of bridges as well as long span PC bridges.