• Journal of the Korean Geotechnical Society
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• v.27 no.1
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• pp.35-40
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• 2011

Dredging and disposal is a conventional method to remove contaminated sediments. However, there are some problems in dredging and disposal, such as disturbance of contaminated sediments, disposal site determination, and high construction cost. Recently, in-situ capping which overcomes the problems of dredging and disposal is widely applied to isolate local contaminated sites. Numerical studies, which have been conducted to simulate contaminant transport during in-situ capping, have been concerned mainly with diffusive transport. However, contaminated sediments experience large strain consolidation induced by self-weight because of initially high moisture content of sediments, and contaminant transport results from advection and diffusion. Previous studies focus on contaminant transport during consolidation, but have neglected consolidation effect on long-term contaminant transport in sediments. This study presents numerical simulation results of consolidation effect on long-term contaminant transport in sediments.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.75-81
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• 2009

The industrial by-products market has increased at a geometric rate worldwide with the rapid economic growth. Among the wide variety of industrial by-products, fly ash which is generated by the combustion of coal is one of the more troublesome industrial wastes because they entail substantial disposal cost and also cause a shortage of disposal sites. In Korea alone, fly ash generation is expected to increase to 5.8 million tons by 2009, and to 6 million tons by 2010. Given the accelerated industrial development in developing countries, the amount of fly ash generation is predicted to reach enormous levels throughout the world. An increasing number of studies have currently focused on the feasibility of recycling industrial wastes i.e., fly ash in terms of environmental advantages. In this study, the optimized mix proportion of high performance shotcrete using fly ash was determined for the purpose of promoting recycling and reuse of resources.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.535-538
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• 2007

Since 1980s, the government has established the overall country development master plan for balance development of country, it set basic aim of restraint overcrowding of the metropolitan area and devising a regional balance development for development policy. But, new urban development master plan which if propelled has revised development master plan for stabilization of housing cost through supply housing in the metropolitan area, not reviewed discussion suitability of development plan with policy propulsion, efficient pre-plan, negotiation with local self-administration community, convergence opinion of local resident, environmental impact evaluation. therefore, we should suggest considerations related to policy and development when it propelled solution of housing inefficience in the metropolitan area and new urban development policy for harmony of central function in capital.

• The KIPS Transactions:PartA
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• v.13A no.2 s.99
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• pp.147-156
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• 2006

Recently, streaming service accounts for large part of internet traffic and it is becoming the most popular service. Because of P2P's scalability, P2P-based streaming system is proposed. There are frequent leave and join of a node. To overcome the group dynamics, Multiple Multicast Trees Methods were suggested. However, since they did not consider discrepancy in peers' capacity, it may cause the trees to be long and unstable. So we suggest Resilient Capacity-Aware Multicast Tree construction scheme (R-CAT) that promotes superior peer to upper position in the tree and construct more stable and short multicast trees. By simulation we can show that R-CAT cost more overhead packets for tree joining process, but it reduce the end-to-end delay of the resulting tree and the number of packets lost during the node joining and leaving processes much more than SplitStream.

• Land and Housing Review
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• v.3 no.2
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• pp.169-175
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• 2012

In recent, there are many studies associated with energy piles to save initial construction cost for ground source heat pump system. In this study, to evaluate geothermal exchange rates two types (a connection type and a slinky type) of cast-in-place energy piles (PRD, 4.5m in depth, 1,200 mm in diameter) were constructed for the tests and their efficiencies were compared with numerical analysis results. As a result, starting with operation, geothermal exchange rate gradually decreases due to exchange of lower ground temperature. In the case of connection type, temperature difference is $0.37^{\circ}C$ in heating mode and $0.34^{\circ}C$, in cooling mode, respectively. In addition, in case of a connection type, geothermal exchange rate in heating mode is 2,314W/m and in cooling mode, 252.2W/m whose value is 9% higher than in heating mode. In the case of slinky type, the average geothermal exchange rate in heating mode is 168.0W/m, which is about 27% lower than that of connection type.

• Korean Journal of Construction Engineering and Management
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• v.21 no.5
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• pp.38-45
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• 2020

Presently, safety management of facilities is conducted as a site-oriented safety inspection, but depending on the facilities, there are difficulties in access to the site, and the cost and time of inspection are inefficient due to excessive reliance on human resources. Therefore, the necessity of sensor-based safety management is being raised to ensure the safety of the facility at all times, and various studies on sensor safety management are being conducted, but the research on verification of practicality is still insufficient. Therefore, the improvement points were presented through analysis of domestic and international studies, and additional processes for setting sensor attachment location and threshold were derived by analyzing the H city sensor safety management process, and practicality of sensor safety management was verified through sensor data measurement values. It is expected that efficient, sensor-based facility safety management will be possible if clear criteria and ongoing practicality verification for the additional processes presented in this study should be carried out in the future.

• Korean Journal of Construction Engineering and Management
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• v.22 no.4
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• pp.41-49
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• 2021

Domestic maintenance strategies are shifting from safety assessment to performance assessment, and related systems and laws are being restructured to meet those criteria. In order to introduce asset management based on performance evaluation, related evaluation methods such as performance measures and level of service should be made to evaluate performance according to the characteristics of the structure, but these are not well-prepared in Korea. In this study, we present a computerized model and system for implementing asset management that introduces techniques such as performance evaluation, life cycle cost analysis, performance measures, and level of service in conjunction with existing maintenance and safety diagnosis procedures. The features of this system consist of three modules to enable separate operations of existing maintenance, safety management and asset management. The system is designed to be used as a reference for public institutions to introduce asset management in the future.

• Plant Journal
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• v.14 no.4
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• pp.48-54
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• 2018

As the emission limits for NOx in power generation facilities were strengthened, HRSGs installed in the 1990s became necessary to install additional DeNOx system. However, since there is no space in the HRSG for installing the entire the catalyst and ammonia injection grid, as an alternative, the catalyst was installed inside of the HRSG and the ammonia injection device was installed in the exhaust duct of the gas turbine. Experiments were conducted in horizontal HRSG of Incheon combined cycle power plant. Experimental results show that the ammonia injection method in the gas turbine exhaust duct is 1.2 times higher than the HRSG internal ammonia injection method. However when operating a HRSG for 30 years as its life span, ammonia injection method in the gas turbine exhaust duct is more economical than the cost of new HRSG construction.

• Journal of Navigation and Port Research
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• v.31 no.3 s.119
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• pp.165-172
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• 2007

Logistics needs in Asia are surprisingly increasing due to rapid growth of China in Northeast Asia We are endeavoring to make an economic block in opposition to NAFTA and EU by economic revival, political stability, and easing of exclusive parts between countries as increasing of traffic infra such as asian highway, transcontinental railway in the region of Northeast Asia and as considering diversification of transportation mode. Now, Busan is not a final terminal of this business, and it is not a concreted level in considering an undersea tunnel between Korea and Japan as effort to extend to Japan. Therefore, this study performed an effect analysis which be affected to Northeast Asia and Korea in future by analysis and comparison of a cost and time required of marine transportation and railway before and after construction through course analysis and summary of discussed content until now for undersea tunnel between Korea and Japan. This result expects as a accelerative play for study cf undersea tunnel between Korea and Japan in future. In this result, we estimate that it is an effective things in a cost and time required if undersea tunnel between Korea and Japan is constructed, and we simply searched for theirs effects in the aspects of Northeast Asia, national balanced development, regional economic in Busan, and marine logistics.

• Korean Journal of Construction Engineering and Management
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• v.13 no.4
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• pp.141-151
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• 2012

Infrastructure are the essential element in the country for they are the basic facilities forming the basis of economic activity. In Korea Infrastructure which are subject to the management of government are increasing annually, and subsequently the budget of maintenance costs is expected to rise significantly. For the effective management of the constructed and accumulated infrastructure, the integrated management of the future assets will be needed which includes the determination of the asset status, management subjects, and the location, the maintenance of their performance and state, and the prediction of the cost required to increase their useful lifetime. However, in the domestic cases the road facilities valuation has not been done systematically, and the preparation and research on this is scarce. Thus, the systematic procedure for the road facilities valuation is required. In this paper the following study was conducted to derive the reasonable asset valuation methods. First, the valuation methods was investigated and summarized throughout the domestic and international research literature. Second, to apply the investigated valuation methods to the road facilities the valuation process that reflects domestic conditions and characteristics has been developed. Third, a working Bridge, Highways, and General national ways were applied to the general valuation process, and the results were analyzed. As a final step a schematic diagram of the asset management support by WDRC valuation method was presented.