• 전기학회논문지P
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• 제67권4호
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• pp.221-226
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• 2018

In this paper, the power transfer efficiency analysis based on the resonant repeater in a magnetic resonance wireless power transfer system is proposed. The efficiency of the magnetic resonance method was verified by comparing the general frequency with the resonance frequency. The resonance repeater was arranged to increase the efficiency and increase the transfer distance. When using resonant repeaters, the maximum efficiency increase is about 36.23[%] and the transfer distance was extended to more than 20[cm]. Through this study, confirmed the effect of using resonance repeaters in wireless power transfer system. As a result, it can be expected that the overall technology related to wireless power transfer system will be more valuable for energy-IT technology.

• 국제학술발표논문집
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• The 10th International Conference on Construction Engineering and Project Management
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• pp.193-200
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• 2024

This research focuses on the extent to which the water efficiency elective items of the LEED certification system adapt to the environmental characteristics of regions with varying climatic conditions. The building industry, is being called upon to promote energy-efficient construction, and the issues surrounding water resources are becoming increasingly severe, underscoring the importance of sustainable water resource management. Based on the hypothesis that, despite its global recognition and widespread adoption, the LEED certification does not always adequately address the environmental realities of all regions, this study analyzed new construction cases certified by LEED in the United States, Japan, and Taiwan from 2019 to February 2024. The analysis revealed regional differences based on water efficiency elective items and certification level trends under different climatic conditions. The findings suggest that the LEED certification system may not fully respond to the environmental situations and water resource issues in all regions, raising concerns about the adaptability of water efficiency items and the potential for similar issues in other evaluation items.

• 한국철도학회논문집
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• 제12권6호
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• pp.1030-1036
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• 2009

본 연구에서는 철도산업의 효율성을 측정하는데 있어 내부요인인 운영기관의 생산활동 뿐만 아니라 구조개혁으로 인한 조직유형, 사회경제적 관점에서 통제 불가능한 환경요인 등이 철도산업 효율성을 결정짓는데 어떠한 영향을 미치는지 분석하였다. 우리나라를 비롯하여 1990년 이후 구조개혁이 활발히 진행된 유럽국가와 일본을 대상으로, 철도산업 효율성 측정에 적합한 DEA방법을 이용하여 1990년~2006년까지의 효율성 값을 구하였다. 그 결과 우리나라는 모든 연도에 걸쳐 상대적으로 효율적으로 추정되었고, 전반적으로 평가대상국들의 효율성이 시간이 지남에 따라 향상되었음을 나타내었다. 또한 효율성 결정요인을 분석하고자 DEA방법으로 추정된 효율성 값을 종속변수로 하고, 구조개혁으로 인한 조직유형, 사회경제적 환경요인을 독립변수로 한 Tobit 분석에서는 시설과 운영을 분리하는 수직적 분리와 화물과 여객을 분리하는 수평적 분리가 효율성에 긍정적인 영향을 미치는 것으로 나타났다. 이는 철도산업의 경쟁력 강화와 경영효율성을 제고하기 위한 구조개혁은 그 과정과 결과에 대한 신중한 검토 및 평가가 이루어져야 함을 시사하였다.

• 한국태양에너지학회 논문집
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• 제32권2호
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• pp.19-27
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• 2012

This paper describes an experimental study on efficiency of solar collector in solar water heating system connected to hourly water heating load. In general, the functional form of solar efficiency is expressed as a function of fluid temperature entering solar collector, ambient temperature, and solar irradiance. When energy saving from solar heating of water heating system is analyzed on along-term basis such as one year with given solar irradiance data, simplified analysis is more convenient han detailed system simulation for quick assessment. However, the functional form of the efficiency is not convenient for approximately simplified energy analysis because the inlet temperature can be obtained through a detailed system simulation. In the study, solar collector efficiency is obtained with various daily water heating load sand daily solar irradiance using experimental tests. The study also considers large residential buildings such as apartment buildings for application of solar water heating systems. From test results, it is found that daily solar collector efficiency is proportional to daily water heating loads and daily solar irradiance. The data obtained from the study can be utilized to find a functional relation between daily solar irradiance and daily heating load in stead of collector inlet temperature for application of solar collector efficiency to long-term approximated energy analysis of solar heating system.

• International Journal of Railway
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• 제6권2호
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• pp.33-44
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• 2013

In recent years, energy consumption in the transportation sector by expanding motorization continues to increase in almost every country in the world. Moreover, the growth rate of the transportation energy consumption is significantly higher than those of the civilian and industrial sectors. Therefore, every country strives to reduce its dependence on private transport, which is the main contributor to the transportation energy consumption. In many countries, concepts such as Transit Oriented Development (TOD) or New Urbanism, which controls road traffic by increasing the proportion of the public transportation significantly, have been implemented to encourage a modal shift to public transport. However, the level of change required for eliminating environmental problems is a challenging task. Minimizing transportation energy consumption by controlling the increase of the traffic demand and maintaining the level of urban mobility simultaneously is a pressing dilemma for each city. Grasping the impact of the diversity of the urban transport and infrastructure is very important to improve transportation energy efficiency. However, the potential for reducing urban transportation energy consumption has often been ineffectively demonstrated by the diversity of cities. Therefore, the accuracy of evaluating the current efficiency rate of the urban energy consumption is necessary. Nevertheless, quantitative analyses related to the efficiency of transportation energy consumption are scarce, and the research on the current condition of consumption efficiency based on international quantitative analysis is almost nonexistent. On the basis of this background problem definitions, this research first built a database of the transportation energy consumption of private modes in 119 cities, with an attempt to reflect individual travel behaviors calculated by Person Trip data. Subsequently, Data Envelopment Analysis (DEA) was used as an assessment method to evaluate the efficiency of transportation energy consumption by considering the diversity of the urban traffic features in the world cities. Finally, we clarified the current condition of consumption efficiency by attempting to propose a target values for improving transportation energy consumption.

• 디지털융복합연구
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• 제17권12호
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• pp.129-137
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• 2019

본 연구의 목적은 중국 자치성별 과학기술 예산활용 효율성을 분석하고 개선방향을 제시하는 것이다. 중국교육부가 공시한 2013-2017년의 고등교육 통계연감에서 데이터를 확보하여, 맘퀴스트 분석방법을 활용해 투입대비 산출의 효율성을 분석하였다. 분석결과 기술 진보가 낮은 것은 생산성 MPI지수의 변동을 일으키는 원인이며, 기술적 효율성의 영향을 받은 도시는 효율성을 높이려면 지역 내 대학의 내부 조율, 구조조정 등 내부적 요인의 개선이 필요한 것으로 파악되었다. 기술변화의 영향을 받은 지역은 정부정책, 경제 환경, 사회 환경이나 기술의 발전 등 외적 요인에 대한 적절한 대응이 필요한 것으로 파악되었다. 본 연구는 중국의 자치성별로 과학기술 예산활용 효율성을 제고하는 데에 참고자료를 제시하였다는데 의의가 있으며, 향후 비효율적인 지역의 효율성을 높이기 위한 전략의 수립 및 필수적인 요소에 대한 연구가 필요하다.

• 디지털융복합연구
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• 제17권12호
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• pp.147-157
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• 2019

본 연구의 목적은 도시화 과정에서 생산되는 바람직한 산출과 기대 하지 않는 산출 모두를 포함하여 중국 31개 성과 직할시에 대해 도시화 효율성을 분석하는 것이다. 중국 31개 성 및 직할시의 2017년 도시화 관련 산출 데이터를 활용하여 SBM-DEA모델을 적용해 효율성을 분석하였다. 분석결과 동부지역의 도시화 효율이 가장 높고 중부와 동북지역의 도시화 효율이 그 다음으로 낮으며 서부지역은 도시화 효율이 상대적으로 가장 낮은 것으로 나타났다. 본 연구는 중국 31개 성 및 직할시의 도시화 추진의 효율성을 분석하고 지속적인 도시화 정책 추진의 방향을 제시하였다는데 의의가 있다. 이번 연구는 2017년 1년간의 횡단면적 분석만 시행하여 과거의 추이를 반영하지 못한 한계가 있으며, 향후 종단면적 분석을 추가적으로 실시하여 도시화 효율성을 종합적으로 평가할 필요가 있다.

• 대한교통학회지
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• 제28권5호
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• pp.31-41
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• 2010

본 논문에서는 2005년 1사분기부터 2009년 3사분기까지 개별 화물자동차 운전자들의 실제 화물운송 실적자료를 이용하여 영업용 도로화물운송업의 업종 및 품목별 생산 효율성을 평가하고, 위탁관리제 및 다단계거래 등 규제적 요인을 포함하여 영업용 도로화물운송업의 생산 효율성에 영향을 미치는 요인들을 분석하였다. 구체적으로 영업용 도로화물운송업의 생산 효율성 평가를 위해 자료포락분석법을 적용하였고, 개별 화물자동차 운전자들의 생산 효율성에 미치는 영향요인을 분석하기 위해 토빗모형을 이용하였다. 분석결과, 개별화물과 용달화물보다는 일반화물 업종의 생산 효율성이 더 높은 것으로 분석되었으며, 품목별로는 철강화물의 생산 효율성이 가장 높고, 유류화물의 생산 효율성이 가장 낮은 것으로 평가되었다. 특히 시간이 지남에 따라 영업용 도로화물운송업의 생산 효율성은 소폭 증감을 보이고 있으나, 전반적으로 증가하는 추세를 보이고 있다. 아울러 본 연구에서는 실증분석결과를 토대로 영업용 도로화물운송업의 생산 효율성 증대를 위한 정책방향을 제시하였다.

• Journal of Korea Trade
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• 제25권1호
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• pp.169-183
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• 2021

Purpose - This paper analyzes the effect of the agricultural export market for Korea's new southern countries in consideration of logistics efficiency. In order to expand Korean agricultural exports, the logistics performance index, national income, per capita income, consumer price index, distance and FTA are included. Through empirical analysis, the impact of logistics efficiency on Korean agricultural exports is derived and measures are proposed to expand exports in the future. Design/methodology - The analytical model of this study takes into account the import demand factors of the new southern countries for Korean agricultural exports. A research model was established based on prior research based on the gravity model, which is widely used in international trade effect analysis. In particular, logistics efficiency measures the effect on Korean agricultural exports using the logistics performance index and examines the effect by deriving factors for export expansion. Findings - The main findings of this study can be summarized as follows: The higher the logistics efficiency of the new southern countries in exporting Korean agricultural products, the more directly they have an effect on expanding exports. In addition, it was analyzed that the expansion of Korean agricultural exports has a positive effect on the other countries' national income, per capita income, consumer price index, population, and FTA. Based on these results, the importance of efficient logistics management in agricultural exports has been emphasized. Originality/value - There are not many studies on the export of agricultural products by logistics efficiency. However, prior studies that have adapted to manufacturing and other areas suggest that logistics efficiency has a direct effect on exports. This study suggests that Korean agricultural products are directly effective in exporting to new southern countries in terms of logistics efficiency. This can be an important time point in recognizing that logistics capabilities are important to ensure new books and the safety of agricultural products.

• Journal of Korea Trade
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• 제27권4호
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• pp.1-18
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• 2023

Purpose - The purpose of this paper is to study how flexibility and mutuality in determining trade terms impact logistics efficiency in the context of relational theory. Additionally, the effect of relational contracts on logistical efficiency relative to the value of the goods being traded is investigated. Design/methodology - According to the relational contract theory, we developed 17 factors utilizing a 7-point Likert scale to measure variables related to flexibility, mutuality, logistics efficiency, and the added value of goods. The survey occurred over four months, and was distributed directly, and via email, phone, and online Google surveys. A total of 403 surveys were collected out of 1,800 distributed, and 380 were analyzed. The principal respondents were import/export companies and members of the Korea International Trade Association and the Korea Small and Medium Business Export-Import Association. The collected data were analyzed using frequency analysis, exploratory factor analysis, and correlation analysis using SPSS ver. 26.0 statistical software, and hypothesis test results were derived using Process Macro ver. 3.5. Findings - This study provides evidence that negotiation flexibility for trade terms affects the efficiency of the logistics process, and the mutuality of such arrangements is shown to be associated with the flexibility and efficiency of logistics processes. Additionally, it has been established that companies whose trade goods possess a low degree of added value may experience increased efficiency in logistics operations if they agree to trade terms that are both flexible and mutually beneficial with their counterparts. Originality/value - This study suggests that in an environment of rapidly shifting global logistics and unpredictable related costs, trade companies may be able to improve logistics efficiency by establishing flexible, mutually beneficial trade terms when entering into contracts. Furthermore, it is suggested that companies dealing in low-value-added products may improve the logistical performance of approaching trade from a perspective of relational contracts.