• 대한전기학회논문지:전력기술부문A
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• 제49권7호
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• pp.359-364
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• 2000

This paper is introducing a newly developed spark-gap switch with dual trigger system, into which the current from the voltage source is injected along with the test sequence during the synthetic testing of high voltage circuit-breaker. The currently-used spark gap switch is narrow in operating range due to the use of the method of triggering energy being injected by single way. As a result, the frequent happening of misoperation has greatly reduced the test quality and test efficiency and has required the cost of maintenance excessively. In this study, accordingly, in order to basically remove these problems, another triggering system is installed to the opposite direction on the existing triggering system; attaching the same time and the same rising time of pulse wave as on the existing system, so that at a comparatively trigger gap distance from the main electrode(the gap can be operated at 60% of self-break voltage, while at 80% in the current system), the main electrode has been enabled to be closed by the development of spark gap switch with dual trigger system.

• 한국통신학회논문지
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• 제39C권2호
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• pp.184-190
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• 2014

선박 통신은 1993년 ISO에서 국제 표준 규격인 RS-422통신을 이용하며, 마이크로컨트롤러들 간의 통신을 위해 설계된 시리얼 네트워크 통신 방식을 사용하였으나, 최근 NMEA2000 표준화가 진행됨에 따라 점차 빠르게 Ethernet 기반 통신 환경으로 대체 되어질 전망이다. 선박에서 사용되어지고 있는 주요 계측 장비들은 점차 범용성과 편의성을 가지는 최신 장치들을 이용해 이를 관리하게 되어짐에 따라 선박 내 다양한 곳에서 이를 활용하여 제어 및 관리 시스템들이 구현되어지고 있는 실정이다. 풍향 풍속계는 선박의 마스트 끝이나 풍력 단지 가장 높은 곳에 일반적으로 설치되어 풍향과 풍속을 계측하는 장비로써, 국제해사기구(IMO : International Maritime Organization)의 규정에 따라 필수 장비로 선박에 탑재되고 있는 장비이다. 본 논문에서는 초음파 풍향 풍속 시스템을 처리하기 위해 기존에는 별도 제어 콘솔, 데이터 로거(data-logger), 인디케이터(Indicator) 등의 제어 처리를 위한 기반 장비들이 필요하였던 시스템을 사용자 환경에 따른 PC NETWORK를 이용하여 풍향 풍속 자료 처리시스템을 구현하였다. 또한, 초음파 풍향 풍속 자료 처리 시스템을 구현하기 위한 요소 기술을 기능별 함수로 나타내었으며, NMEA 2000 표준 인증에서도 별도의 운용 콘솔 없이 풍향 풍속 자료의 처리를 위한 자료 처리 운용시스템의 기능들을 구현하고자 하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.46-53
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• 1999

As of July 1999, i,185 lomocotives(excluding metropolitan area electric locomotives) are in Korean National Railroad(KNR). With this limited number of resources assigning locomotives to each trains of timetable is very important in the entire railway management point of view because schedule can be regarded as goods in transportation industry. On a simple rail network, it is rather easier to assign proper locomotives to trains with the experience of operating experts and get optimal assignment solution. However, as the network is getting bigger and complicated, the number of trains and corresponding locomotives will be dramatically increased to rover all the demands required to service all of the trains in timetable. There will be also numerous operational constraints to be considered. Assigning proper locomotives to trains and building optimal cyclic rotations of locomotive routings will result in increasing efficiency of schedule and giving a guarantee of more profit. The purpose of this study is two fold: (1) we consider a planning-level locomotive scheduling problem with the objective of minimizing the wasting cost under various practical constraints and (2) development of implementation prototype program of its assigning result. Not like other countries, i.e. Canada, Sweden, Korean railroad operates on n daily schedule basis. The objective is to find optimal assignment of locomotives of different types to each trains, which minimize the wasting cost. This problem is defined on a planning stage and therefore, does not consider operational constraints such as maintenance and emergency cases. Due to the large scale of the problem size and complexity, we approach with heuristic methods and column generation to find optimal solution. The locomotive scheduling prototype consists of several modules including database, optimization engine and diagram generator. The optimization engine solves MIP model and provides an optimal locomotive schedule using specified optimization algorithms. A cyclic locomotive route diagram can be generated using this optimal schedule through the diagram generator.

• 수산경영론집
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• 제33권1호
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• pp.43-68
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• 2002

In the fisheries industry, the cost of oil Is the greatest factor, contributing 25% 40% of the cost of production. In order to support fisheries, the government has supplied large amounts of money for oil to the fisheries industry. However, the elimination and restriction against the subsidy of fisheries has been actively discussed throughout international organizations Including the WTO. The purpose of this thesis is to study the existing issue of subsidies on the fisheries Industry, which is currently disputed in international organizations, and predict a future policy about the oil supply that considers the most important factors on fisheries. In chapter 2, the paper begins by outlining the tendencies of discussion in relation to the subsidy on fisheries among international organizations, and categorizes them on the basis of their types. Chapter 3 defines the current conditions and characteristics of the Korean subsidy on fisheries and analyzes which portions of the subsidy on fisheries should be eliminated first when it is prohibited. In chapter 4, procedures and problems for producing tax-free oil are discussed, because tax-free oil has a higher possibility of being ruled out. Chapter 5 proposes a reasonable plan concerning oil supply policies for maintenance or enrichment of the fishing industries, post the elimination of subsidies. Conclusions were drawn in eight areas as a result of this study: 1) securing the large storage of oil, 2) extending customers of oil to include non-fishermen, 3) coordinating the segmentation of marketing area, 4) diversification of the sales goods, 5) producing oil sales experts, 6) developing original brands, 7) expanding the purchasing area to buy oil in the international market, and 8) operating funds to stabilize oil price. It would not be appropriate to wait until international organizations decide to ban the subsidy of fisheries. Corresponding plans ( such as securing the large storage of oil) tend to be large scale and long-term projects because they take a number of years, from designing the oil storage tank to selecting the proper region and initiating the construction. Therefore, it is strongly suggested that any extensive and time consuming projects including preparation for the tax-free oil should be completed in new actions before the ban by the international organizations.

• 한국도로학회논문집
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• 제11권4호
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• pp.117-126
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• 2009

한국도로공사는 40년간 육상교통의 대동맥인 고속국도의 건설 및 운영 대부분을 담당하고 있다. 90년대 이후부터 민영에 의한 고속국도가 건설 및 운영중에 있다. 하지만, 2001년부터 2008년까지 최소운영수입 보장금 명목으로 중앙정부와 지방자치단체가 2001년-2008년까지 민자사업자에게 1조 5,896억원을 지급하였다. 이와 같은 현실에서 한국고속국도 대부분의 건설 및 운영을 담당하고 있는 한국도로공사의 비용구조 파악이 중요한 의미가 있을 것이다. 분석결과 노동과 자본 운영이 높은 교차탄력성을 나타내 높은 대체성이 존재하며, 자본과 운영은 자본의 상승(고속국도 연장 증가)과 고속국도 노후화에 따른 대체성은 다소 존재하지만, 낮은 대체 탄력성을 나타내고 있다. 한국도로공사는 대체적으로 투입요소가 효율적으로 이용되고 있으며, 노동과 자본 운영의 대체탄력성이 높게 나타나 한국도로공사는 전략적으로 아웃소싱 활성화(영업부문)와 영업과 건설(유지관리 포함) 재무적 분리가 필요할 것으로 판단된다. 또한, 고속국도 운영기관의 통합과 함께 하이패스를 활성화 시킨다면, 보다 우리나라 고속국도의 운영의 효율성은 상승시킬 것으로 판단된다.

• 대한조선학회논문집
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• 제53권2호
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• pp.115-126
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• 2016

In the process of ship building, it is known that the maintenance of working period and saving cost are one of the important part during the logistics of blocks transportation. Precise operational planning inside the shipyard plays a big role for a smooth transportation of blocks. But many problems arise in the process of block transportation such as the inevitable road damage during the transportation of the blocks, unpredictable stockyard utilization of the road associated with a particular lot number, addition of unplanned blocks. Therefore, operational plan needs to be re-established frequently in real time for an efficient block management. In order to find the shortest path between lot numbers, there are several representative methods such as Floyd algorithm that has the characteristics of many-to-many mapping, Dijkstra algorithm that has the characteristic of one-to-many mapping, and the A* algorithm which has the one-to-one mapping, but many authors have published without the mutual comparisons of these algorithms. In this study, some appropriate comparison have been reviewed about the advantages and disadvantages of these algorithms in terms of precision and cost analysis of calculating the paths and planning system to operate the transporters. The flexible operating plan is proposed to handle a situation such as damaged path, changing process during block transportation. In addition, an operational algorithm of a vacant transporter is proposed to cover the shortest path in a minimum time considering the situation of transporter rotation for practical use.

• 대한기계학회논문집 C: 기술과 교육
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• 제2권2호
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• pp.89-97
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• 2014

내륙의 주전력 공급계통과 단절되어 있는 도서지역은 대부분의 전력공급을 디젤발전설비가 담당하고 있다. 디젤발전설비는 특성상 예방정비 및 유지보수를 통해 사용수명을 연장시킬 수 있으나, 계속 사용에 따른 기계설비의 노후화 및 발전 효율 감소로 인해 운영비가 증가한다. 즉, 적기에 노후 발전설비를 교체할 경우 발전소 운영비용을 줄일 수 있다. 이에 본 연구에서는 디젤발전설비의 상태를 대표할 수 있는 지표를 도출하고, 몬테카를로 시뮬레이션을 이용하여 각 지표별 민감도 분석을 수행하고자 한다. 이를 통해 디젤발전설비의 현상태를 정량적으로 나타낼 수 있는 상태점수를 정의하고 이를 바탕으로 설비 교체의 기준을 마련하고자 한다.

• Agribusiness and Information Management
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• 제8권1호
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• pp.17-26
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• 2016

India is largest producer of banana in the world producing 29.72 million tonnes from an area of 0.803 million ha with a productivity of 35.7 MT ha-1 and accounted for 15.48 and 27.01 per cent of the world's area and production respectively (www.nhb.gov.in). In India, Tamil Nadu leads other states both in terms of area and production followed by Maharashtra, Gujarat and Andhra Pradesh. In Rayalaseema region of Andhra Pradesh, Kurnool district had special reputation in the cultivation of banana in an area of 5765 hectares with an annual production of 2.01 lakh tonnes in the year 2012-13 and hence, it was purposively chosen for the study. On $23^{rd}$ November 2003, the Government of Andhra Pradesh has commenced a comprehensive project called 'Andhra Pradesh Micro Irrigation Project (APMIP)', first of its kind in the world so as to promote water use efficiency. APMIP is offering 100 per cent of subsidy in case of SC, ST and 90 per cent in case of other categories of farmers up to 5.0 acres of land. In case of acreage between 5-10 acres, 70 per cent subsidy and acreage above 10, 50 per cent of subsidy is given to the farmer beneficiaries. The sampling frame consists of Kurnool district, two mandals, four villages and 180 sample farmers comprising of 60 farmers each from Marginal (<1ha), Small (1-2ha) and Other (>2ha) categories. A well structured pre-tested schedule was employed to collect the requisite information pertaining to the performance of drip irrigation among the sample farmers and Data Envelopment Analysis (DEA) model was employed to analyze the performance of drip irrigation in banana farms. The performance of drip irrigation was assessed based on the parameters like: Land Development Works (LDW), Fertigation costs (FC), Volume of water supplied (VWS), Annual maintenance costs of drip irrigation (AMC), Economic Status of the farmer (ES), Crop Productivity (CP) etc. The first four parameters are considered as inputs and last two as outputs for DEA modelling purposes. The findings revealed that, the number of farms operating at CRS are more in number in other farms (46.66%) followed by marginal (45%) and small farms (28.33%). Similarly, regarding the number of farmers operating at VRS, the other farms are again more in number with 61.66 per cent followed by marginal (53.33%) and small farms (35%). With reference to scale efficiency, marginal farms dominate the scenario with 57 per cent followed by others (55%) and small farms (50%). At pooled level, 26.11 per cent of the farms are being operated at CRS with an average technical efficiency score of 0.6138 i.e., 47 out of 180 farms. Nearly 40 per cent of the farmers at pooled level are being operated at VRS with an average technical efficiency score of 0.7241. As regards to scale efficiency, nearly 52 per cent of the farmers (94 out of 180 farmers) at pooled level, 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). Majority of the farms (39.44%) are operating at IRS and only 29 per cent of the farmers are operating at DRS. This signifies that, more resources should be provided to these farms operating at IRS and the same should be decreased towards the farms operating at DRS. Nearly 32 per cent of the farms are operating at CRS indicating efficient utilization of resources. Log linear regression model was used to analyze the major determinants of input use efficiency in banana farms. The input variables considered under DEA model were again considered as influential factors for the CRS obtained for the three categories of farmers. Volume of water supplied ($X_1$) and fertigation cost ($X_2$) are the major determinants of banana farms across all the farmer categories and even at pooled level. In view of their positive influence on the CRS, it is essential to strengthen modern irrigation infrastructure like drip irrigation and offer more fertilizer subsidies to the farmer to enhance the crop production on cost-effective basis in Kurnool district of Andhra Pradesh, India. This study further suggests that, the present era of Information Technology will help the irrigation management in the context of generating new techniques, extension, adoption and information. It will also guide the farmers in irrigation scheduling and quantifying the irrigation water requirements in accordance with the water availability in a particular season. So, it is high time for the Government of India to pay adequate attention towards the applications of 'Information and Communication Technology (ICT) and its applications in irrigation water management' for facilitating the deployment of Decision Supports Systems (DSSs) at various levels of planning and management of water resources in the country.

• 품질경영학회지
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• 제44권3호
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• pp.639-648
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• 2016

Purpose: Existing precedent studies include success factors of individual management innovation activities constantly. However, those studies have limitations about the common key success factors of individual management innovation activities. Methods: For this study, we investigate the key success factors using literature research of the most typical management innovation activities adopted and implemented by many companies in Korea, such as 6sigma, TQM, Lean 6sigma, ERP, TPM, BPR, Project Management, System Engineering. Factors emerging repeatedly was combined into common factors and inherent factors that are necessary for the success of individual management innovation activities are designated to essential factors. Results: 'Essential factors for Six Sigma' consist of 5 items. Black belt operating system, personnel management system linkage, the correct management of the data, perform improvement projects associated with financial performance financial result, linked to financial performance improvement project, project progress management. 'Essential factors of TQM' are arranged 4 items. Quality team's independence and role, goal-setting, Quality Information System, corporate's philosophy of quality first. 'Essential factors of Lean Six Sigma' are the selection of value stream which is based on the customer needs and the value creation and identify the project based on the selected value in the company. 'Essential factors of ERP' are investigated 6 items. Ongoing system maintenance and upgrades, the measurement and support of user satisfaction, the operating systems and the policies for the maintenance, IT infrastructure, change adaption condition monitoring, focusing on improving business performance. 'Essential factors for TPM' are arranged 4 items. Motivated and energetic Bottom-Up, CEO's recognition of the importance facility management, long-term perspective of necessity and ongoing patience. 'Essential factors for BPR' are the pursuit of change process and the staff's sense of crisis management. 'Essential factors for Project Management' are the strategy that reduce the risk management skills through risk management and the understanding and organized management for the project participant's needs. 'Essential factors for System Engineering' consist of 2 items. The first is the design for the best balanced system with pre-analysis about the compromise the cost, schedule and the performance. The second is the analysis of large problem into small problems which can solved. We have found the solution considering components of the interface through the systematic perspective. Conclusion: Common factors and essential factors presented in this study will properly help to introduce the individual management innovation activities for the each business sector and implement management innovation. After this study, new literature research that reflect new studies should accomplish steadily.

• 유통과학연구
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• 제14권3호
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• pp.73-83
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• 2016

Purpose - The parcel delivery service(courier) industry all over the world has been expanding its market so far, but its growth has been declining in recent years. In this situation, most parcel delivery companies are having trouble with managing themselves because of the pressure from the customer to increase service level and decrease the rate. The purpose of this study is to provide ways to improve competitive advantages of the parcel delivery service industry by evaluating the multi-period operating efficiency of Korea, Japan and global service providers. Research design, data, and methodology - The data for the period of 2011 to 2014 were collected from the annual reports published by parcel delivery companies. In this study, we analyze the marketability (revenue), profitability (operating profits), and management conditions (net profits) of parcel service companies by combining information on human resources (number of employees) and material resources (total assets and equity). Therefore, the number of employees, total assets, and equity are selected as input variables, and revenue, operating profits, and net profits as the output variables. In this study, DEA (Data Envelopment Analysis) is used to measure the comparative efficiency and MPI (Malmquist Productivity Index) is used to analyze the trend of change of the efficiency for a multi-year period. Results - The operational efficiency scores of medium-sized parcel delivery companies in Korea are higher than other larger competitors such as Korean, Japan and Global larger companies. As of 2014, Logen(1.878) was found to be the most efficient parcel delivery enterprise, followed by KGB (1.224), and Kyoungdong(1.002). Otherwise, Hanjin(0.235), CJ(0.262), Hyundai Logistics(0.657), DHL(0.611), UPS(0.766), FedEx(0.498), TNT(0.350), Yamato(0.762) and Sagawa(0.520), larger sized companies, were done inefficiently. The productivity of parcel delivery companies is influenced by endogenous factors as well as exogenous ones such as changes in business environment and technological advances. Conclusions - Korean medium-sized companies have relatively high efficiency scores in operation. That is why they still survive the competitive market in Korea where market restructuring on the industry has been expected to be conducted for many years. The reason why medium-sized couriers had higher efficient scores than larger couriers is that most of couriers spend more operating expenses versus unit price of delivery which is the amount of money that is needed in order to send a package by parcel service. So the delivery unit price must be taken into account by all the expenses associated with the cost of fuel, labor and maintenance expenses for facilities, etc. therefore, the unit price must be increased to strengthen business competitive power. In order for the industry to have more competitive advantage, the companies need to make profits by increasing demand volume and raising the delivery rate to provide high-quality delivery service to customers. And both endogenous and exogenous change must take precedence in order to strengthen their competitiveness.