• Journal of Distribution Science
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• v.20 no.11
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• pp.109-120
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• 2022

Purpose: We would like to identify the appropriate size of stores in the commercial district suitable for the era of low growth. In addition, it is intended to present alternatives to prevent gentrification along with measures to revitalize commercial districts according to the selection of appropriate stores. Research design, data and methodology: The importance and commercial district usage patterns were identified through surveys by consumers and sellers. the demand and size of the commercial area were calculated based on the floating population and resident registration population. In addition, based on this, through metric analysis, the importance of the business district activation plan and what important matters can prevent gentrification were analyzed. Result: In this the study, 555 stores are currently operating in the target area, but it is seen as a commercial district with a scale that can operate 136 stores and 938 stores. In addition, it was analyzed that the Commercial Lease Protection Act needs to be strengthened to prevent gentrification. Conclusions: Due to the nature of small and medium-sized cities in Korea, commercial districts that have once lost their resilience must take much effort to find vitality. It is believed that local commercial districts will have resilience when diagnosis and recovery measures are adequately presented.

• Agribusiness and Information Management
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• v.8 no.2
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• pp.1-8
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• 2016

The present study has aimed at analyzing the technical and scale efficiencies of credit utilization by the farmer-borrowers in Chittoor district of Andhra Pradesh, India. DEA approach was followed to analyze the credit utilization efficiency and to analyze the factors influencing the credit utilization efficiency, log-linear regression analysis was attempted. DEA analysis revealed that, the number of farmers operating at CRS are more in number in marginal farms (40%) followed by other (35%) and small (17.5%) farms. Regarding the number of farmers operating at VRS, small farmers dominate the scenario with 72.5 per cent followed by other (67.5%) and marginal (42.5%) farmers. With reference to scale efficiency, marginal farmers are in majority (52.5%) followed by other (47.5%) and small (25%) farmers. At the pooled level, 26.7 per cent of the farmers are being operated at CRS, 63 per cent at VRS and 32.5 per cent of the farmers are either performed at the optimum scale or were close to the optimum scale (farms having scale efficiency values equal to or more than 0.90). Nearly 58, 15 and 28 percents of the farmers in the marginal farms category were found operating in the region of increasing, decreasing and constant returns respectively. Compared to marginal farmers category, there are less number of farmers operating at CRS both in small farmers category (15%) and other farmers category (22.5%). At the pooled level, only 5 per cent of the farmers are operating at DRS, majority of the farmers (73%) are operating at IRS and only 22 per cent of the farmers are operating at CRS indicating efficient utilization of credit. The log-linear regression model fitted to analyze the major determinants of credit utilization (technical) efficiency of farmer-borrowers revealed that, the three variables viz., cost of cultivation and family expenditure (both negatively influencing at 1% significant level) and family income (positively influencing at 1% significant level) are the major determinants of credit utilization efficiency across all the selected farmers categories and at pooled level. The analysis further indicate that, escalation in the cost of cultivation of crop enterprises in the region, rise in family expenditure and prior indebtedness of the farmers are showing adverse influence on the credit utilization efficiency of the farmer-borrowers.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.825-832
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• 2008

A simulation program is developed for analysing thermal networking process between the District heating and the CES(Community Energy Supply) systems. The effects of thermal networking on the District heating facilities previously being operated are implemented using mathematical correlations in terms of the fuel consumption and energy load such as heating and electricity. The operational characteristics according to the prime movers is modeled based on the materials of efficiency as a function of operational load. The unit energy load model is also developed extensively for several building types such as apartment complex, hotel, hospital, buildings for business and commercial use respectively. The specific features of the newly developed program in simulation of thermal networking process in district heating is described in terms of the reliability and the easiness for operating it etc.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.663-668
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• 2008

This study was carried out solar heating system design for district heating and it's the performance analysis by experiment. This experimental system was installed in Bundang district heating area in the end of 2006. The flat plate and vacuum tube solar collector are combined in one system. So district heating water is heated first by flat plate solar collector and than by vacuum tube solar collector. This solar heating system has not a solar buffer tank and is operating with variable flow rate to obtain a setting temperature of $90{\sim}95^{\circ}C$. As a result, the daily solar thermal collection efficiency is about 30 to 40% for the plate type and 50 to 55% for the vacuum tube solar collector. It varied especially depend on the weather condition like as solar radiation and ambient temperature. This variable flow rate system can be also reduced much pumping power more than 50%.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.185-187
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• 2000

Fault current is flowed into 154/23kV M. Tr when line-to-ground fault occurs in power system. NGR(Neutral Grounded Reactor) is set up in order to prevent M.Tr fault by limiting magnitude of fault currents. Here, disconnection of NGR causes voltage increase by L-C resonance and line-to-ground fault in an unearthed system results in voltage increase at healthy phases. So Over Voltage Ground Relay(OVGR) is used for tripping M.Tr. Also, buses at second phases of M.Trs are all connected with section circuit breakers closed for the purpose of parallel operation and load shedding. In case of speciality buses are comprised of power cable in part for GIS connection. When no-load charged cable or bus is open by a section CB, unbalanced voltage charged on the bus is induced. Also discrepant opening time for circuit breakers on different phases gives rise to unbalanced zero sequence voltage. It was observed that this zero sequence voltage detected in the 22.9kV P.T (Potential Transformer for bus) mal-operated 59GT and tripped M.Tr. The zero sequence voltage of which vanishing time is longer than relay operating time came out by EMTDC simulation. Also, it was shown that the voltage waves of actual test are similar to those of simulation. On the basis of above results, R-C circuit complement on the relay without any effect on a power system made operating time of the relay longer than vanishing time of distorted waves. Consequently, operating time of the relay was delayed and magnitude of distorted waves was decreased by increasing time constant of the relay.

• Journal of Energy Engineering
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• v.21 no.2
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• pp.144-151
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• 2012

A district heating system produces thermal energy and supplies it to a large region. District heating systems can provide higher efficiencies and better pollution control than localized boilers. The heat generated by a district heating system is distributed to the customer via a network of insulated pipes. For the optimal operation of a district heating system, it is important to predict the distributions of pressure, flow rate and temperature of heating fluid within the network of pipes at various operating conditions. In this work, a mathematical modeling was performed to predict the dynamic hydraulic-thermal behaviors of heating fluid in the network of pipes for a district heating system. The mathematical model accounts for the conservations of mass, momentum and energy. In order to verify the validity of modeling, the modeling results were compared with the monitoring data of Gang-nam Branch of District Heating.

• Journal of Korean Society of Rural Planning
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• v.23 no.3
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• pp.107-120
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• 2017

This study started with drawing problems of early implementation and suggesting improvement plans in order to lead a rural convergence industrialization district system to early settlement and management for its policy goals. The study aimed at 13 districts that were designated from 2014 to 2016 for analyzing an actual condition of promoting early implementation, and went ahead with it combining literature research, interview survey and specialist opinion investigation. The study examined and organized an outline, policy goal, and actual condition of rural convergence industrialization district. Furthermore, it analyzed an actual condition of promoting at each stage such as designating processes of rural convergence industrialization districts, operating body and system, regulation improvement, district supporting projects and relating projects, drew problems and finally suggested improvement plans. This study could be meaningful because it is the first study to grasp an actual condition of promoting early implementation and to remedy problems in order to manage rural convergence industrialization district system which was newly promoted since 2014 for its policy goal. In addition, it suggests that the further study of the result after managing district system for a certain period of time should be needed.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.569-579
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• 2011

Heating pipes, which are among the main equipment in district heating systems, can be classified into supply and return pipes. Because when the district heating transmission pipe, which is charged with district heating in small to medium-size cities, is under thermal stress during temperature variances in heating water, it suffers from the fatigue phenomenon caused by the thermal stress, according to the number of its service years. District heatingpipes have shown various characteristics according to the operating condition of the service connections, and the irregular temperature variance has had a bad influence on fatigue heating pipes. Therefore, in this study, a field test on laid heating pipes was performed, and the data for each region were analyzed. Also, the fatigue safety of district heating pipes was evaluated via cycle-based evaluation and stress-based evaluation.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.3
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• pp.105-115
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• 2000

The purpose of paper is to investigate the characteristics of regulations on landscape management of historic city of Kyongju in Korea, compared with those of Nara in japan to answer the research question that what is the regulative characteristics of landscape management of historic city in Korea. We have analyzed the three laws of the two country - Urban Planning Law, Cultural Assets Protection law, and Building Law. This research has been done in terms of regulative systems of the two country and articles, ordinances, and bylaws on landscape managements of historic city Major components of urban historic landscape management are goals and devices of preservation, preserving actor, authorized actor permitting major planning change, regulatory power on landscape development, and backgrounds of enacting regulations. From this research, we have fond the fact that 1) Kyongju City has general and implicit objectives of landscape management based on conservation of natural environment while Nara City has concrete objectives of lansdscape management, 2) Kyongju City has no regulations on landscape planning while Nara City has systematic planning measures such as designation of landscape management district, planning for preservation of historic landscape, and planning for establishing urban landscape, 3) In an application of landscape management district, Kyongju City designate the district based on the general principle of urban planning district while nara City designate it in a more detailed manner such as district of preservation of historic landscape, district of landscape establishment, and district of building agreement. 4) Kyongju has no legal actor in implementation and management of historic landscape plan while Nara City has administrative organization and procedures, including citizen participation, public hearing, and voluntary participation, and 5) Kyongju City does not operate the consultation committee on landscape management just like Nara City operating. This research results will provide us the remedial insights for landscape preservation of such Korean historic city as Kongju, Puyo, and Chunju. Since our research is focused on the limited area of preserving landscape in historic cities in korea and Japan we need to study sociocultural issues on preserving urban historic landscape more in depth in the future.

• IE interfaces
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• v.24 no.4
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• pp.373-378
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• 2011

High level of accuracy in forecasting heat demand of each district is required for operating and managing the district heating efficiently. Heat demand has a close connection with the demands of the previous days and the temperature, general demand forecasting methods may be used forecast. However, there are some exceptional situations to apply general methods such as the exceptional low demand in weekends or vacation period. We introduce a new method to forecast the heat demand to overcome these situations, using the linearities between the demand and some other factors. Our method uses the temperature and the past 7 days' demands as the factors which determine the future demand. The model consists of daily and hourly models which are multiple linear regression models. Appling these two models to historical data, we confirmed that our method can forecast the heat demand correctly with reasonable errors.