• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.2
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• pp.9-17
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• 2011

Based on the statistical annual report, there are 17,649 reservoirs are operating for the purpose of agricultural water supply in Korea. 58 % of entire agricultural reservoirs had been constructed before 1948 which indicate the termination of required service life and rest of those reservoirs have also exposed to the dam break risk by extreme flood event caused by current ongoing climate change. To prevent damages from dam failure accident of these risky small size dams, it is necessary to evaluate and manage the structural and hydrological safety of the reservoirs. In this study, a simplified evaluation method for hydrologic safety of dam is suggested by using Rational and Creager formula. Hydrologic safety of small scale dams has evaluated by calculating flood discharge capacity of the spillway and compares the results with design frequency of each reservoir. Applicability and stability of suggested simplified method have examined and reviewd by comparing the results from rainfall-runoff modeling with dam break simulation using HEC-HMS. Application results of developed methodology for three sample reservoirs show that simplified assessment method tends to calculate greater inflow to the reservoirs then HEC-HMS model which lead lowered hydrologic safety of reservoirs. Based on the results of application, it is expected that the developed methodology can be adapted as useful tool for small scale reservoir's hydrologic safety evaluation.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1710-1715
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• 2010

Service life of water pipes buried in the underground is considerably affected from various factors such as environmental characteristics, pipe characteristics, operation and maintenance, etc. Therefore it is difficult to determine their service life as uniformly the same value assigned by related laws and ordinances. As a result, the service life should be determined by the technical judgement based on the assessment for the condition of water pipes. In this study, It was established that the methodology could predict present and future failure risk, and plan short and long-term strategies for replacement/rehabilitation through the assessment for the physical deterioration and economical values of buried water pipe. The methodology was applied for the verification and reliability to several sites selected in multi-regional transmission pipelines. The proposed method could helps to support reasonable and economical decision of rehabilitation/replacement in the present and future. To improve conventional assessment method of aged water pipes, affecting factors are simplified based on the statistical analysis results from the measured data in the field and the physical deterioration mechanism for better reliability. Also, the guide-line is developed to carry out the reasonal rehabilitation planning through water pipe condition assessment.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.233-242
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• 2020

As studies and developments of nano-material increase, the release of the nano-sized material to water environment increase. Especially, silver nanoparticles have been found as dissolved and particulate state since nano-silver particle have been intensively used in industrial and our living environment due to the anti-bacterial effect of the nano-particles. The silver nano-particles and silver ion gives adverse effect on ecology and US-EPA set a secondary drinking water standards as 0.1 mg/L. Current study focused on the analysis of silver in groundwater, small scale water supply systems in Gyeongbook area. The results have been compared with the secondary drinking water standards and discussed at the point of characteristics of the local area and purpose of use of the water sample. Among the total of 298 samples, 2 samples exceed the secondary drinking water standards of EPA, 0.64% rate. Community drinking water and simplified water service showed relatively high detection rate and groundwater gave relatively higher concentration of silver indicating anthropogenic source and natural source could contribute simultaneously on groundwater.

• Culinary science and hospitality research
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• v.9 no.4
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• pp.54-68
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• 2003

This study aims at efficiency of kitchen management by adoption of a systematic central kitchen and conversion of conventional kitchen to convenience kitchen at ' H ' restaurant. First, integrated menu control of banquet buffet functions became more competitive with quality menu and eventually brought about guests satisfaction. Second, systematic central kitchen made possible standardization and mass production through simplified production line. Efficiency through quick service and shortened preparation time was realized, and food materials were recycled effectively at the same time. Integrated ordering lowered purchasing price and built an efficient cost control system. Third, conversion of conventional kitchen to convenience kitchen and strengthened central kitchen system facilitated agreeable work conditions and optimal work flow with butcher's and even sauce making utensils. Fourth, integrated supply system of buffet menu and sauce from western restaurants saved about 520 million won of labor costs. Last, one integrated kitchen out of two was easier in sanitation control with pleasant restaurant space. Sharing kitchen facilities and equipments also saved about 30% of maintenance fee. Power, water, and gas were also saved and eventually curtailed overall expenses.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.4
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• pp.330-335
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• 2011

This paper presents estimation of average compressive strengths of three types of stiffened panels under lateral pressure and axial compression based on simplified formulas from CSRs and nonlinear FEAs. FEA scenarios are prepared based on the slenderness ratios of the stiffened panels used for in-service vessels. The seven step lateral pressures by 1bar increment are imposed on FE models assuming maximum 30m water height. The number of FEAs for FB-, AB-, and TB-stiffened panels is totally 189 times. FEA results show that existence of pressure can evolves significant reduction of ultimate strengths, meanwhile CSR formulas do not take into account the lateral pressure effect. Lateral pressure acting on the stiffened panel with higher column slenderness ratio more reduces the ultimate strengths than those with smaller column slenderness ratio. A new concept of relative average compressive strain energy instead of the ultimate strength is introduced in order to rationally compare the average compressive strength through complete compressive straining regime. The differences of the ultimate strengths between CSR formulas and FEA results are relatively small for FB- and AB-stiffened panels, but larger discrepancies of relative average compressive strain energies are shown.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.129-136
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• 2017

Climate change is the biggest environmental issue of our times. A variety of activities to reduce greenhouse gas emissions have been in progress to observe the Kyoto Protocol. Especially, the Energy Target Scheme is created to reduce greenhouse emission with the supervision of Korean government. This includes Green-house Gas Information Systems to promote activities in the private sector to reduce green-house gas emissions, to cut a cost of energy use, and to reduce GHG emissions. Also, the system has calculated the amount of greenhouse gases. Without any additional investment, 2.75% savings are increased over the previous year. In service sector, a cooperation of customers and employees is necessary. A reduction of GHG emissions requires a proper service organization, considering an amount of investment and payback period. Without any additional investment or replacement, employees can save energy easily turning off ventilation systems an hour before employees' departure, installing timers to turn off water purifiers and vending machines after some period of no use. The Green-house Gas Information System is similar to that of Environmental Management System. However, the Excel is the best program to calculate an amount of green-house gas emissions, and to assess for a reduced amount of GHG emissions. A goal of this research is to propose a practical method in the private sector to calculate an amount of green-house gases. The Green-house gas Information System based on Excel spreadsheet gives standards for good evaluation. The greenhouse gas information system establishes and executes the policies and objectives related to greenhouse gas emissions Similar to ISO 14001 environment management system structures, the advantages of using simplified Excel Sheet for calculating GHG emissions and reducing GHG emissions are easy to access.