• Korean Management Science Review
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• v.31 no.2
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• pp.1-13
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• 2014

In almost all of the organizations, the cost for acquiring and maintaining the inventory takes a considerable portion of the management budget, and thus a certain constraint is set upon the budget itself. The previous studies on inventory control for each item that aimed to improve the fill rate, backorder, and the expenditure on inventory are fitting for the commercially-operated SCM, but show some discrepancies when they are applied to the spare parts for repairing disabled systems. Therefore, many studies on systematic approach concept considering spare parts of various kinds simultaneously have been conducted to achieve effective performance for the inventory control at a lower cost, and primarily, METRIC series models can be named. However, the past studies were limited when dealing with the probability distributions for representing the situation on demand and transportation of the parts, with the (S-1, S) inventory control policy, and so on. To address these shortcomings, the Continuous Time Markov Chain (CTMC) model, which considers the phase-type distributions and the (s, Q) inventory control policies to best describe the real-world situations inclusively, is presented in this study. Additionally, by considering the cost versus the system availability, the optimization of the inventory level, based on this model, is also covered.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.885-901
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• 2020

A forest watershed management project was introduced in 2004 to develop ecologically sound forest watersheds. It includes landslide prevention and erosion control, water resource management, landscape development, and forest resource management. However, it has been managed fragmentarily and inefficiently, far from the original intents. This study investigated current status, problems, and improvement measures of the project. Literature reviews were conducted on forest watershed management in Korea and other countries, and surveys were conducted on 201 erosion control experts. When introduced, the forest watershed management project was well planned and implemented as intended. It later turned to focus only on disaster prevention such as erosion control dams and stream conservation measures. The survey results showed that a majority (89% and 86%) of surveyees wanted increases in the project period and budget. They also responded that conflicts with local residents (51%) and determining project locations (32%) were the most difficult tasks when implementing the projects, and only 36% kept project records. To plan and implement the projects as intended, the following suggestions should be considered: (1) establishment of a solid legal foundation and improvement of the erosion control practices law; (2) increase in the project period (from 1 to 2 - 3 years) and budget; (3) development of a manual for project site selection and guidelines; (4) monitoring and systematic information management; and (5) development of spatial analysis tools for watershed analysis and management.

• Journal of the Korea Safety Management & Science
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• v.8 no.5
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• pp.131-137
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• 2006

The Cost has been much emphasized in inside of an army because of the promotion of reconciliation atmosphere between South and North Korea and the reduction of defense budget since 1990. So we are now faced with the problem that we should consider a cost above all besides the performance and arrangement for such a restriction of budget in time of developing new generation weapon systems. In this research we are suggested following two methodologies. One is the develop a weapon system with optimum cost considering a Life Cycle Cost from the first stage of design and the other is the cost control and management with the establishment of Target cost.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.104-108
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• 1998

Analysis of energy budget in Neomysis awatschensis exposed to PCB toxicity was carried out by measurement of bioassay, growth, oxygen consumption, nitrogen excretion at 10 and $20^{\circ}C$. Energy contents of the body, molted exoskeleton and eggs, which measured to understand used energy for growth, molt and oxygen consumption were 5.52cal/mg, 2.17 cal/mg and 6.15 cal/mg, respectively. Feeding energies at $10^{\circ}C$ were 3.755ca1 in control group and 3.420 cal at 2.0 ppb concentration, of them, $70.19\%$ and $67.53\%$ of their energies were assimilated. At $20^{\circ}C$, feeding energies were 5.998 cal in control group and 4.166 cal at 2.0 ppb concentration. The assimilation efficiency of the mysid estimated by ash-ratio method ranged between $11.5\~67.5\%$ and $73.4\~70.5\%$ with PCB toxicity at $10^{\circ}C$ and $20^{\circ}C$ respectively. Energy used by respiration of total assimilated energy was $45.18\%$ in control group and $62.27\%$ in 2.0 pub concentration at $20^{\circ}C$, and energy used by metabolism was high 2.0 ppb concentration than control group.

• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.105-114
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• 2022

The purpose of this study was to present a conceptual design of the 6U micro-satellite system for optical image of 3 m GSD. An optical camera system with a payload of 3 m GSD image was designed and optimized. The optical system has a diameter of Ø78 mm, length 250 mm, and 1400 mm focal length. The requirement and constraints were configured for the 6U micro-satellite bus system with the payload. Satisfying the requirement and constraints, the subsystems of the 6U bus were designed such as attitude and orbit control, propulsion, command and data handling, electrical power, communication, structures and mechanisms, and thermal control subsystem. The mass budget, power budget, and communication link budget were also confirmed for the 6U micro-satellite comprising the optical payload and the subsystems of bus. To take optical images, a mission operation concept is proposed for the 6U micro-satellite in a low-Earth orbit. A constellation comprising many 6U micro-satellites studied in this paper, can provide with various data for reconnaissance and disaster tracking.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.190-197
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• 2012

The purpose of this study was to evaluate thermal environment and heat budget of light thin layer green roof through an experiment in order to quantify its heat budget. Two concrete model boxes($1.2m(W){\times}1.2m(D){\times}1.0m(H)$) were constructed: One experiment box with Zoysia japonica planted on substrate depth of 10cm and one control box without any plant. Between June 6th and 7th, 2012, outside climatic conditions(air temperature, relative humidity, wind direction, wind speed), evapotranspiration, surface and ceiling temperature, heat flux, and heat budget of the boxes were measured. Daily maximum temperature of those two days was $29.4^{\circ}C$ and $30^{\circ}C$, and daily evapotranspiration was $2,686.1g/m^2$ and $3,312.8g/m^2$, respectively. It was found that evapotranspiration increased as the quantity of solar radiation increased. A surface and ceiling temperature of those two boxes was compared when outside air temperature was the greatest. and control box showed a greater temperature in both cases. Thus it was found that green roof was effective in reducing temperature. As results of heat budget analysis, heat budget of a green roof showed a greater proportion of net radiation and latent heat while heat budget of the control box showed a greater proportion of sensible heat and conduction heat. The significance of this study was to analyze heat budget of green roof temperature reduction. As substrate depth and types, species and seasonal changes may have influences on temperature reduction of green roof, further study is necessary.

• Journal of Advanced Navigation Technology
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• v.8 no.1
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• pp.19-26
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• 2004

This paper deals with the automatic flight control system for an unmanned target drone which is operated by an army as an anti-air gun shooting training. By automation of unmanned target drone that is manually operated by external pilot, pilot can reduce workload and an army can reduce the budget. Most UAVs which are developed until today use high-cost sensors as AHRS and IMU to measure the attitude, but those are contradictory for the reduction of budget. This paper says the development of low-cost automatic flight control system which makes possible of automatic flight with low-cost sensors. We have developed the integrated automatic flight control system by integrating electricity module, switching module, monitoring module and RC receiver as an one module. We also prove the performance of automatic flight control system by flight test.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.201-203
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• 2015

편안한 3차원 입체영상 콘텐츠 제작을 위해선 시청 환경 조건에 부합하는 최적의 제작 방법을 필요로 한다. 현재의 입체영상 제작 과정은 경험자의 지식이나 시청자 실험에 기반 한 가이드라인들을 활용하고 있으나, 특정 제작 환경에 국한되어 있다. 보다 구체적이고 정량적인 가이드라인 도출을 위해선 다양한 카메라 제어 및 시청 환경 요소를 고려한 실험용 입체영상이 제작되고, 그 실험 영상을 기반으로 다양한 시청자 실험 데이터가 구축되어야 한다. 또한, 실험용 입체영상 제작은 단기간에 이루어지고, 실험 목적 변경에 따라 변화 요인을 수용할 수 있어야 한다. 본 논문에서는 다양한 실험용 입체영상 제작을 위해, 상업용 3D 게임 엔진 저작 툴(Unity3D)에서 운용되고, 깊이예산(Depth Budget) 제어가 쉽게 가능한 입체 카메라 모듈을 구현하고, 구현된 모듈을 활용한 입체영상의 제작 예를 보여준다.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.2
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• pp.15-25
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• 2004

For the effective operation of irrigation reservoirs, a general and systematic policy is suggested to make balance of the conflicting purposes between water conservation and flood control. In this study, the flood effective analysis system was developed through the integration of long-term water budget analysis model, GIS-based HEC-HMS model and HEC-RAS model. The system structure consists of long-term water budget model using modified TANK theory, flood runoff and flood effects analysis model using HEC-GeoHMS, HEC-HMS and HEC-RAS models. The flood effects analysis system simulated the flood runoff from the upstream, downstream flood and long-term runoff of the watershed using the observed data collected from 1998 to 2002 of Seongju dam. The simulated results were reasonably good compared with the observed data. The optimal management method of the reservoir during the whole season is suggested in this study, and the flood analysis system can be a useful tool to evaluate a reservoir operation quantitatively for the mitigation of flood damages of reservoir basin.

• Journal of the Korean Society for Library and Information Science
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• v.6
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• pp.105-135
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• 1979

This paper is intended to analyze and investigate the versity libraries in Korea. Nineteen national col-present status of four-year national college and unileges and universities based on a number of faculty member, enrollment, department, library staff, volumes in library, academic journals, book budget and facilities of library, and so we have to improve and develop a kind of problems with which national college and university libraries are confronted as follows: 1) Establishment of a position for the INFORMATION SPECIALIST. 2) Reorganization of the organization of college and university library. 3) Securing a position for the EDUCATIONAL RESEARCHER. 4) Upgrading a part of temporary employees. 5) Securing a self-control of library's administration. 6) Revising rules for labor employees in library. 7) Revising a STANDARD STATEMENT FOR ESTABLISHMENT OF UNIVERSITY. (Books and academic journals) 8) ' ( Facilities of library ) 9) Increase of a budget of library and establishing for an article of library budget. 10) Establishment of a new department exclusively responsible for library administration in the Ministry of Education. 11) Giving a leading(proper) role to Seoul National University Library among the other college and university libraries. 12) Establishment of The master course of INFORMATION SCIENCE or THE RESEARCH CENTER FOR INFORMATION SCIENCE in Seoul National University.