• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.111-122
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• 2007

This paper investigates the rail service patterns by train class. The emphasis in intercity rail planning is to more efficiently use of existing station facilities. Rail transit operations are affected by the system layout and ridership patterns and by work rules. Operations are also influenced by past practices and the institutional setting. Main factors to decide train service patterns are the location, socioeconomic characteristics, land use and travel demand of the station. In this context, the travel demand of intercity rail station is of crucial significance. Tests on a KTX case shows that train service frequency can be efficiently decreased in weekday to transport the same passenger demand. The work has shown many subjects that need further research including various factors influencing on train frequency. This study serves the railroad authorities in planning and determining business strategy in the increasingly competitive environment of regional rail transport.

• Clean Technology
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• v.2 no.2
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• pp.201-213
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• 1996

Environmental regulation has traditionally focused on specific phenomena and adopted the so-called end-of-pipe approach. Recently, however, the new environmental paradigm is more concerned with minimization of waste generation, efficient material and energy use, pollution prevention, etc. The basis of above concept is that one must consider the environmental impacts of a product not only during its manufacturing stage, but during all life stages. In the present study, the current status of LCA and its importance to environmental impacts have been reviewed. In the usual approach to LCA, screening LCA method has been used to promote international competition and define environmental concerns during semiconductor manufacturing. In the present study, a review of semiconductor manufacturing process and its environmental implication has been conducted to quantify the material and energy requirements, minimize the waste generation, and evaluate production cost. Recommended activities are also specified for process modification to improve the process efficiency.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.70-81
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• 2018

Claims in the construction industry can have a serious impact on the profitability of the project or can even result in project failure if it fails to take appropriate prevention. In order to properly prevent and respond to the potential claims and legal disputes throughout the project execution, it is necessary to continuously accumulate informations and clearly define the roles and responsibilities of the important activities systematically. Based on these needs, this study develops and verifies the project information management system(PMIS) that can prevent and respond possible claims for construction projects. Developed system includes such management modules as schedule, cost, PM/CM, design, collaboration, and claims. The system was validated by adopting it to the practical projects. The results showed that information systems tailored to the construction claim need to elevate users' familiarity to be more useful. Besides, the system can be more functional when used by both owners and contractors.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.698-707
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• 2011

Over the past 10 years, South Korea has implemented various plantation projects including the Pine Restoration Project in Tujiin Nars and the desertification prevention forestation in Lun soum. This study has evaluated the implementation feasibility on the small-scale A/R CDM projects in Mongolia through which carbon emission credits can be secured. Characteristics, pros and cons, economic feasibility, and project execution feasibility were compared among three possible sites, Khyalganat, Tujiin Nars, and Lun soum. Among the three evaluated sites, Tujiin Nars has the better condition in tree growth, economic feasibility, and the applicability of experience than the other two sites. A/R CDM project in Mongolia, which has a great environmental benefit of combating desertification, is expected to have some effectiveness such as lowering costs from credit benefit, sustainable management by villagers, contribution to communities, investor's contribution to society and achievement of green image, and strengthening forestry cooperation between Korea and Mongolia.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.887-892
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• 2022

Due to various reasons (normally financial constraints in developing countries), it becomes common to change of the business model from state-run projects to Private Investment Projects (Public Private Partnership) in the global railway businesses. However, due to the nature of railroads compared with other types of infrastructure such as roads and others, railway business require considerable construction cost and O&M cost through the business development, construction, and operation and management stages. Therefore, private investment railway projects, especially in developing countries, can be problematic in terms of the potential for uncertainty when return on investment cannot be guaranteed. In order to strengthen the competitiveness of domestic companies when entering overseas railroad PPP projects, this study proposes PPP-related risks and their countermeasures by reviewing global railroad trends and identifying Korea's weakness in managing international railroad projects.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.843-852
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• 2022

Despite continuous safety management, the death rate of construction workers is not decreasing every year. Accordingly, various studies are in progress to prevent construction site accidents. In this paper, we developed an AI-based priority inspection target selection model that preferentially selects sites are expected to cause construction accidents among construction sites with construction costs of less than 5 billion won (KRW). In particular, Random Forest (90.48 % of accident prediction AUC-ROC) showed the best performance among applied AI algorithms (Classification analysis). The main factors causing construction accidents were construction costs, total number of construction days and the number of construction performance evaluations. In this study an ROI (return of investment) of about 917.7 % can be predicted over 8 years as a result of better efficiency of manual inspections human resource and a preemptive response to construction accidents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.312-321
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• 2018

The Korean DR market proposes suppression of peak demand under reliability crisis caused a natural disaster or unexpected power plant accidents as well as saving power plant construction costs and expanding amount of reserve as utility's perspective. End-user is notified a DR event signal DR execution before one hour, and executes DR based on requested amount of load reduction. This paper proposes a DR energy management algorithm that can be scheduled the optimal operations of chiller system and ESS in the next day considering the TOU tariff and DR scheme. In this DR algorithm is divided into two scheduling's; day-ahead operation scheduling with temperature forecasting error and operation rescheduling on DR operation. In day-ahead operation scheduling, the operations of DR resources are scheduled based on the finite number of ambient temperature scenarios, which have been generated based on the historical ambient temperature data. As well as, the uncertainties in DR event including requested amount of load reduction and specified DR duration are also considered as scenarios. Also, operation rescheduling on DR operation day is proposed to ensure thermal comfort and the benefit of a COB owner. The proposed method minimizes the expected energy cost by a mixed integer linear programming (MILP).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.135-142
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• 2017

This study employs an analytical mathematical model to estimate the optimal debt ratio of Korean agricultural corporations, more sensitive to the government debt ratio policy compared to other industries, and the estimation of the optimal debt ratio based on objective data. The analytical model utilizes the equation for ROE, with the debt ratio as an independent variable, and related parameters include ROS, TAT, and NFCL. Regarding the NFCL, the optimal debt ratio standard is defined as the debt ratio that maximizes the ROE by analytical procedures such as adding an equation concerning the debt ratio and a linearity relationship to the analytical model, and from these equations, a quadratic equation with the debt ratio as an independent variable describes the ROE. This methodemploys fourteen years of corporate data. Results show that 138% of debt ratio is the optimal debt ratio to increase the ROE of the corporations, which implies that the existing debt ratio of Korean agricultural corporations is higher than optimal. Consequently, it is required for authorities to change future debt ratio policies in view that the purpose of debt ratio management is to maintain safety and increase profitability.Management should emphasize characteristics of the specific industry rather than standardized judgements based on numerical indexes.

• Journal of Climate Change Research
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• v.2 no.4
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• pp.283-295
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• 2011

Many actions against climate change have been taken to reduce greenhouse gases (GHGs) emissions at home and abroad. As of 2007, the GHGs emitted from buildings accounted for about 23 % of Korea's total GHGs emission, which is the second largest GHG reduction potential following industry. In this study, we introduced Carbon Zero Building (CZB), which was constructed by the National Institute of Environmental Research to cut down GHGs from buildings in Korea, and evaluated the main applied technologies, the amount of energy load and reduced energy, and economic values for CZB to provide data that could be a basis in the future construction of this kind of carbon-neutral buildings. A total of 66 technologies were applied for this building in order to achieve carbon zero emissions. Applied technologies include 30 energy consumption reduction technologies, 18 energy efficiency technologies, and 5 eco-friendly technologies. Out of total annual energy load ($123.8kWh/m^2$), about 40% of energy load ($49kWh/m^2$) was reduced by using passive technologies such as super insulation and use of high efficiency equipments and the other 60% ($74.8kWh/m^2$) was reduced by using active technologies such as solar voltaic, solar thermal, and geothermal energy. The construction cost of CZB was 1.4 times higher than ordinary buildings. However, if active technologies are excluded, the construction cost is similar to that of ordinary buildings. It was estimated that we could save annually about 102 million won directly from energy saving and about 2.2 million won indirectly from additional saving by the reduction in GHGs and atmospheric pollutants. In terms of carbon, we could reduce 100 ton of $CO_2$ emissions per year. In our Life Cycle Cost (LCC) analysis, the Break Even Point (BEP) for the additional construction cost was estimated to be around 20.6 years.

• Journal of Korea Port Economic Association
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• v.24 no.2
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• pp.131-154
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• 2008

The purpose of this paper is to verify the financial validity of dredging the port of Busan with the change of global port logistics circumstances. In order to do so, NPV, IRR, B/C ratio, DPP techniques are adopted. The whole dredging at Northern port area is supposed to be negative at the depth of 16m water. Based upon its financial validity, however, the priority is Shinsundae (option 1) followed by Shinsundae (option 1) and Gamman (option 1), Shinsundae (option 1) and Gamman (option 2), Shinsundae (option 2) and Gamman (option 2), Shinsundae (option 2) and Gamman (option 2) and ShinGamman in sequence. In addition to this, Busan New port is considered to be the positive financial validity at the dredging of 16m water depth. This is because the ultra containerships of over 8,000TEU are trying to call at the port and Hanjin shipping and Hyundai Merchant shipping companies which are now the most significant customers in Northern port are scheduled to divert it.