• Journal of Astronomy and Space Sciences
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• 제34권3호
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• pp.225-235
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• 2017

The energy balance in a satellite needs to be designed properly for the satellite to safely operate and carry out successive missions on an orbit. In this study, an analysis program was developed using the MATLAB(R) graphic user interface (GUI) for nanosatellites. This program was used in a simulation to confirm the generated power, consumed power, and battery power in the satellites on the orbit, and its performance was verified with applying different satellite operational modes and units. For data transmission, STK(R)-MATLAB(R) connectivity was used to send the generated power from STK(R) to MATLAB(R) automatically. Moreover, this program is general-purpose; therefore, it can be applied to nanosatellites that have missions or shapes that are different from those of the satellites in this study. This power simulation tool could be used not only to calculate the suitable power budget when developing the power systems, but also to analyze the remaining energy balance in the satellites.

• International Journal of Aerospace System Engineering
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• 제3권2호
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• pp.31-37
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• 2016

STEP Cube Lab (Cube Laboratory for Space Technology Experimental Project) is a 1U standardized pico-class satellite. Its main mission objective is an on-orbit verification of five fundamental core space technologies. For assuring a successful missions of the STEP Cube Lab with five payloads, electrical power subsystem (EPS) shall sufficiently provide an electrical power to payloads and bus systems of the satellite during an entire mission life. In this study, a design process of EPS system was introduced including power budget analysis considering a mission orbit and various mission modes of the satellite. In conclusion, adequate EPS hardware in compliance with design requirements were selected. The effectiveness and mission capability of EPS architecture design were confirmed through an energy balance analysis (EBA).

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.66-73
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• 2011

With rapid industrialization, electric power consumption has been increasing every year in Korea and in other countries. The provision of additional power stations to produce more electricity is one possible response to this steady increase in consumption. Another alternative is to improve the efficiency of existing stations through timely and effective maintenance works. Since the construction of a new power plant involves a large amount of capital as well as difficulties in the selection of sites, the improvement of existing power stations' efficiencies is often a preferred solution. Therefore, this paper focuses on maintenance project management to address this issue. Among several types of maintenance works, this paper concentrates on planned outage maintenance (POM). This focus arises from the critical impact of POM on other maintenance work, as well as the entire process of electricity production. Unlike other maintenance work, POM is done on the basis of mid and long-term plans. In addition, only POM works are conducted during the outage of all power plants. To evaluate the efficiency of POM works, budget data relating to 164 POM projects between 2001 and 2008 was collected from 7 sites in South Korea. Data envelopment analysis (DEA) was selected as a methodology for evaluation. From this analysis, comparative study was used to determine the categories of projects that had performed well, and those with the most optimized budget structures. Moreover, through discussion with industry, this research develops a feasible proposed method by which to enhance the efficiency of POM projects.

• 신재생에너지
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• 제8권1호
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• pp.8-17
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• 2012

The Korean government pushed ahead various policies to disseminate photovoltaic (PV), wind power, small hydro, bio-fuel, etc. Renewable energy system (RES) budget of the Korean government increased from 118 billion won of 2003 to 876.6 billion won of 2010. The R&D budgetary supports for RES increased by 6.8 times in the period 2003-2010. It is necessary to confirm RES budget expenditure that renewable energy promotion policy makes good performance evaluated in quantity level. This paper made Input-Output Table 2009 contains photovoltaic power generation equipment industry as a dependent sector and analyzed induced production effect by demand of photovoltaic power generation equipment industry. From the empirical analysis result, additional demand in photovoltaic power generation equipment induced 1.932 times of induced production in Korea. Each of industry sector has positive induced production from the additional demand in photovoltaic power generation equipment. Renewable energy promotion in photovoltaic power generation is considered together with industry policy as the option to sustain economic growth.

• 한국방재학회 논문집
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• 제8권4호
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• pp.67-74
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• 2008

소방수요가 증가하고 형태가 다양화되고 있으므로 가장 필요한 것은 소방력을 충분히 보유하기 위하여 소방예산을 확보하는 일이다. 이러한 예산배정은 주민이 원하는 소방서비스를 충분히 제공하게 되어 사회적 후생만족에 기여할 것이다. 만약 소방예산이 소방수요, 소방력에 적합하지 않게 책정된다면, 소방관의 안전은 위협받게 될 것이다. 또한 위급한 재난이 발생하면 지방정부가 재난을 효과적으로 대처할 수 없을 것이다. 실제로 일부 시 군에서는 소방장비의 부족으로 많은 인명과 재산이 피해를 입고 있다. 본 연구의 목적은 소방예산이 소방력에 어떠한 영향을 주는지 알아보는데 있다. 이를 위하여 본 연구에서는 소방력, 소방예산에 대한 조사를 실시하였다. 그 다음, 이론적 배경과 과거연구를 근거로 3가지 가설을 설정하였다. 가설을 검증하기 위한 통계적 방법은 회귀방정식이다. 본 연구 결과, 주민 1인당 소방예산은 소방력에 양(+)의 유의적인 영향을 미쳤으나, 소방예산비율은 소방력에 유의적인 영향을 주지 않았다. 또한 공동시설세는 소방력에 음(-)의 유의적인 영향을 미치는 것으로 나타나, 공동시설세가 목적세로서의 역할을 하지 못하고 있음을 알 수 있었다.

• 정보처리학회논문지C
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• 제9C권3호
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• pp.439-444
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• 2002

본 논문은 무선인터넷서되스의 기반기술인 무선CATV 시스템 방식중에 디지털 MMDS(Multipoint Multichannel Distribution System)의 시스템 파라미터에 따른 링크버짓 분석과 송신 출력과 변조방식에 따른 셀반경을 제시한다. 또한, 본 논문에서는 셀 분할에 따른 C/I와 가입자수를 제시한다. 본 논문에서, 디지털 MMDS의 시스템 파라미터에 따른 링크버짓 분석한 결과를 토대로 0dBW에서 -9dBW가지 송신출력과 QPSK, 16QAM, 그리고 64QAM 변조방식에 따라 구한 결과의 셀 반경은 최대 134km에서 최소 4.3km가지 가능했다 또한, 본 논문에서, 4섹터, 6섹터 그리고 8섹터 셀에서, 편파, 주파수 대역, 주파수 재사용 빈도, C/I에 따라 구한 결과의 가입자수는 최대 5,200DSI(Digital Subcriber Interface)에서 최소 1,300DSI까지 가능했다.

• Journal of Astronomy and Space Sciences
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• 제37권2호
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• pp.117-129
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• 2020

In a Satellite communication system, a link budget analysis is the detailed investigation of signal gains and losses moving through a channel from a sender to receiver. It inspects the fading of passed on data signal waves due to the process of spreading or propagation, including transmitter and receiver antenna gains, feeder cables, and related losses. The extent of the proposed tool is to make an effective, efficient, and user-friendly approach to calculate link budget analysis. It is also related to the satellite communication correlation framework by building up a graphical interface link analysis tool utilizing STK^® software with the interface of C# programming. It provides better kinds of graphical display techniques, exporting and importing data files, printing link information, access data, azimuth-elevation-range (AER), and simulation is also possible at once. The components of the link budget analysis tool include transmitter gain, effective isotropic radiated power (EIRP), free space loss, propagation loss, frequency Doppler shift, flux density, link margin, elevation plot, etc. This tool can be useful for amateur users (e.g., CubeSat developers in the universities) or nanosat developers who may not know about the RF communication system of the satellite and the orbital mechanics (e.g., orbit propagators) principle used in the satellite link analysis.

• 한국정보처리학회논문지
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• 제6권9호
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• pp.2460-2469
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• 1999

최근 다양한 무선통신 서비스가 출현함에 따라 무선호출 서비스의 경쟁력이 요구된다. 본 논문에서는 가격 및 기술 경쟁력을 높이기 위해 양방향 무선호출 위성지구국 시스템을 제안하였고 위성링크를 설계하였으며 무궁화위성을 이용한 무선호출망에 대해 설명하였다. 또한 단말국의 비용을 줄이기 위해 중심국과 단말국의 크기를 다르게 설계하였고, 인바운드와 아웃바운드의 전력배당 방법을 제안하였으며 본 위성링크설계에 이용하였다. 링크설계 결과 강우시간율 0.043%에서 중심국과 단말국의 안테나 크기는 3.7m와 1.2m이고 HPA 크기는 10.37W와 2.0W이며 아웃바운드와 인바운드의 전력배당은 84%와 16%로 설계되었다. 또한 강우시간율 0.02%에서 중심국과 단말국의 안테나 크기는 3.7m와 1.8m 그리고 아웃바운드와 인바운드의 전력배당은 63%와 37%로 설계되었다.

• 조명전기설비학회논문지
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• 제28권12호
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• pp.103-107
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• 2014

Together with housings, general buildings and industrial facilities, multi-purpose complexes are equipped with various and special equipment. They are often used by many unspecified people, which causes an increase in annual electricity consumption. Because of this, a great amount of money has been spent for electric charge, far more in excess of the budget, so a reasonable electricity rate needs to be estimated. In this study, we surveyed the power consumption, average power use, and annual electricity bill of multi-purpose complexes in the past five years. To see the general tendency of the survey, we conducted a statistical analysis with such parameters as average, maximum, and minimum values. Through regression analysis, we could see the trend of the survey in linear way. Based on the survey, we have developed an electric-rate calculation program to estimate the next year's budget on electricity.

• 한국군사과학기술학회지
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• 제23권2호
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• pp.147-158
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• 2020

Korea Ministry of National Defense has directed the state-of-the-art technology Forces troops structures that can respond to security threats in all directions through the Defense Innovation 2.0, which aims to reorganize the personnel and organizations in response to population decline. An implement of effective analysis to maintain combat power is necessary due to possible restrictions on combat power, especially in division of mobilization where reserve manpower is operated frequently. In this study, the normal operations of the reserve officers were investigated, the direct effects of the combat forces of the reserve officers was analyzed using ARENA modeling, and the budget required to operate the innovation and indirect effects of employment of veterans were studied. The result of the simulation proved to be effective in demonstrating unit combat power when the reserve officer was in full-time operations and economic benefits were also significant in terms of efficiency of defense budget management.