• 유통과학연구
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• 제20권11호
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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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• 제8권2호
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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.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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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.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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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%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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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.

• 에너지공학
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• 제21권2호
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• pp.144-151
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• 2012

지역난방시스템이란 열에너지를 생산하고 만들어진 열에너지를 넓은 지역에 공급하는 시스템이다. 지역난방시스템은 국부난방보다 더 효율적이고 친환경적이라고 할 수 있다. 생산 된 열은 단열 배관 네트워크를 통해 사용자들에게 공급된다. 지역난방시스템의 효율적인 운전을 위해서는 여러 가지 운전 조건에서 배관망 네트워크의 유량, 압력 및 온도 분포를 예측하는 것이 중요하다. 본 연구에서는 지역난방용 지중매설 배관망 네트워크에서의 열-유체 동적거동을 수학적 모델을 사용하여 예측하였다. 수학적 모델은 물질, 운동량 및 에너지 수지식을 사용하였다. 모델링의 결과를 검증하기 위하여 강남지역 지역난방시스템에서 측정한 결과와 모델링의 결과를 비교하였다.

• 농촌계획
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• 제23권3호
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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.

• 한국강구조학회 논문집
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• 제23권5호
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• pp.569-579
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• 2011

지역난방 시스템의 주요 구성요소의 하나인 열배관은 크게 공급관과 회수관으로 구분되며, 지역난방에서의 열수송 배관은 난방수의 온도변화에 따른 열응력을 받게 되므로 공용년수 증가에 따라 열응력에 의한 피로현상이 발생하게 된다. 한편 지역난방 열배관은 사용자배관의 공용조건에 따라 다양한 특성을 나타내며 이러한 불규칙한 온도변화는 열배관의 피로에 악영향을 미치게 된다. 따라서 본 연구에서는 기 매설된 공용중인 지역별 열배관에 대해 현장계측을 실시하고 각 지역의 데이터를 분석하였다. 또한 사이클기반 피로평가법 및 응력기반 피로평가법을 통하여 지역난방 열배관의 피로안전성을 평가하였다.

• 한국조경학회지
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• 제28권3호
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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.

• 산업공학
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• 제24권4호
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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.