• 보건행정학회지
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• 제13권2호
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• pp.101-124
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• 2003

Performance of public hospitals is difficult to define and measure because not only their managerial or financial performance but also their role as a public entity is important. The purpose of this paper is to examine the internal and external factors that influence the performance of local government hospitals. A multiple regression was performed to analyze the effects of the environmental, organizational, operational, and cost-related factors on the return on total assets(ROA), operating margin(OM), and the ratio of Medicaid patients. Empirical results show that financial performance (ROA and OM) are more influenced by operational or cost-related factors, while the ratio of Medicaid patients is more affected by environmental or organizational characteristics. It is noteworthy that competition and the contract with private sector management have negative effects on the ratio of Medicaid patients that local government hospitals treat.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.507-513
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• 2004

In the railway system, transportation plan corresponds to a m aster plan for transport services. This service plan must be constructed to minimize operational cost or maximize revenue considering transportation demands and resource capacities in the railway operation company, and it includes several sub-planning activities such as train operation frequency plan, train (schedule) plan, train capacity assignment plan, and rolling stock requirement plan. In these sub- planning processes, train can be con side red as a product for providing customer services, and customer demands and operational advantages must be considered. In this paper, we present an effect estimation system for the train capacity pattern in a train schedule, and the effect of capacity pattern can be expressed as minimum spilled demand, minimum train service cost, and maximum train revenue or profit.

• 전력전자학회논문지
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• 제18권2호
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• pp.192-198
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• 2013

The rapidly growing demand for electric power systems in electric vehicles (EVs) and hybrid electric vehicles (HEVs) require simpler, cost-effective, and higher performance components. In this paper, a novel power conversion system for hybrid electric vehicles is proposed for these needs. The proposed power conversion system reduces the conversion system cost while preserving same functionality. The proposed power conversion system can boost multi-sources to drive a traction motor and to store energy at the same time reducing number of switching components. In this paper, all operational modes of the proposed converter are explained in detail and verified by a computer simulation first. Then, the topology and operational modes are experimentally verified. Based on the results, the feasibility of the proposed multi-mode single leg power conversion system for EV and HEV applications is discussed.

• Archives of Reconstructive Microsurgery
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• 제17권1호
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• pp.48-50
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• 2008

Loupes-assisted microsurgery often needs an operational head lamp for a better condition of light. This may cause serious neck fatigue due to the weight the operational head lamp, the limitation of the operator's head movement from the hind cable, and some cost for purchasing and management of it. On the contrary, a mountain head lamp is very light, full of freedom in movement, applicable to all types of loupes, and relatively very cheap. In conclusion, a mountain head lame can be a cost-effective light source for Loupes-assisted microsurgery.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.19-24
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• 1999

This paper addresses a new project being carried out at Satellite Technology Research Center. The purpose of the project is to implement a system which receives, processes and stores 1m resolution satellite image transmitted at over 300Mbps down link data rates. In order to develop such a system, a system operational concept design and a requirements study were being carried out As a result of the operational concept design, system objectives, system context and system functions were defined. The system shall be operated according to the philosophy of maximum automation. rapid processing, reliability, integrity, cost effectiveness, and expandability. The system is divided into twelve independent processes and its behavior is modeled by operational scenario, which are combinations of independent processes. Process information and logs generated by the system shall be stored in databases and data received and generated be automatically archived and managed in a hierarchical storage device. The system shall have redundant components in order to be ready for recovering from sudden system failures. This paper will describe in detail the system operational concept design and the system requirements derived from the operational concept design.

• 센서학회지
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• 제6권2호
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• pp.145-154
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• 1997

회로 시뮬레이션과 국부적 탐색을 갖는 시뮬레이티드 아닐링을 사용한 새로운 탐색 전략에 기초하여 고성능 연산 증폭기의 설계 자동화를 위한 기법을 제안하였다. 임의의 연산 증폭기 구조와 성능 규격에 대해서, 이산 설계 변수들을 갖는 비용 함수의 이산 최적화를 통해 연산 증폭기의 설계가 이루어진다. 설계 시간의 단축을 위해서 전용 회로 시뮬레이터와 몇 가지 휴리스틱을 사용하였다. 스마트 센서와 10 비트 25 MS/s 파이프라인 A/D 변환기에 사용 가능한 저전력 고속 전차동 CMOS 연산 증폭기의 설계를 통해서, 제안된 기법을 사용하여 개발된 설계 도구는 적은 설계 지식과 설계 노력을 가지고 고성능 연산 증폭기를 설계하는데 사용될 수 있음을 보였다.

• 한국태양에너지학회 논문집
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• 제34권5호
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• pp.33-41
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• 2014

Heliostat field in a tower type solar thermal power plant is the sun tracking mirror system which affects the overall efficiency of solar thermal power plant most significantly while consumes a large amount of energy to operate it. Thus optimal operation of it is very crucial for maximizing the energy collection and, at the same time, for minimizing the operating cost. Heliostat field operational algorithm is the logics to control the heliostat field efficiently so as to optimize the heliostat field optical efficiency and to protect the system from damage as well as to reduce the energy consumption required to operate the field. This work presents the heliostat field operational algorithm developed for the heliostat field of 200kW solar thermal power plant built in Daegu, Korea. We first review the structure of heliostat field control system proposed in the previous work to provide the conceptual framework of how the algorithm developed in this work could be implemented. Then the methodologies to operate the heliostat field properly and efficiently, by defining and explaining the various operation modes, are discussed. A simulation, showing the heat flux distribution collected by the heliostat field at the receiver, is used to show the usefulness of proposed heliostat field operational algorithm.

• 한국농공학회논문집
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• 제50권4호
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• pp.51-58
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• 2008

Unit costs for energy production in bioenergy facilities are dependent upon both fixed cost for facility construction and operational costs including biomass feedstock supply. With the increase of capacity, unit fixed cost could be decreased while supply cost tends to increase due to the longer transportation distance. It is desirable to take into account biomass availability in planning bioenergy facilities. A cumulative curve relationship was proposed to relate biomass availability and cumulative products of biomass amount and transportation distance. Optimum size of gasification facilities was affected by collection cost, biomass cumulative relationship. Based on biomass availability of Icheon-City, optimum sizes were about $400kW_{th}$ for gas production, and about $200kW_{el}$ for power generation. Unit cost of bioenergy production could be substantially reduced by reducing collection cost through supplying biomass from diverse sources including land development areas where significant amount of waste wood is generated. When planning bioenergy facilities, however, biomass availability and spatial distribution are key factors in determining the size of capacity.

• 항공우주산업기술동향
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• 제6권2호
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• pp.69-79
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• 2008

유럽의 우주비행체 시뮬레이터는 요구사항의 증가와 함께 우주비행체 개발 비용에서 높은 비율을 차지하여 개발 비용 절감과 개발 기간 단축의 압력에 직면하고 있다. 현재 유럽은 유럽우주국을 중심으로 다양한 우주프로젝트 경험을 이용하여 소프트웨어 자체의 재사용 연구뿐만 아니라 소프트웨어 요구사항, 설계 노하우, 개발방법론, 경험 등 우주 프로젝트 간의 광범위한 자원 재사용 연구를 활발히 진행하고 있다. 재사용 연구 결과는 시뮬레이션 모델의 표준 제정과 시뮬레이터 개발 프로세스의 효율성 증대로 나타나고 있으며 후속 프로젝트에 적용되어 효과를 입증하고 있다. 본 논문에서는 최근 유럽의 우주비행체 시뮬레이터의 연구동향 추세와 시뮬레이터 소프트웨어 개발 동향을 기술한다.

• 한국군사과학기술학회지
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• 제16권6호
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• pp.762-770
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• 2013

Korean military is currently using and operating a precision approach and landing system, called RAPCON (ASR/PAR), which is imported from overseas. However, drawbacks of this system are operational and cost problems that come along, e.g. straightness of the radio waves, limited ability of narrow searching, lack of interoperability, and high cost of installation and maintenance. Moreover, as the civilian air traffic control uses a similar system compared to the military, the so called DME/VOR/ILS, disturbance between these two systems triggered the consideration of GNSS as alternative system. In this paper, we conduct a research on trends in the field of precise approach and landing systems based on GNSS, analyze weaknesses of GNSS(jamming, fault) and consider possible solutions. Furthermore, we propose the precise approach and landing system based on GNSS to be used by the Korean military as we found it to be also suitable for military purposes. Finally, we examine the benefits of a domestic development with different focuses(development/cost of mass production/operational advantages and potential for increased performance).