• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.117-122
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• 2018

This paper suggests smart agricultural diffusion strategy through advanced ICT technology. Today, the world is threatened by environmental pollution and traditional warming due to global warming, and the decrease in agricultural workers due to low fertility and aging is expected to bring social problems to future food resources. The convergence of ICT technology and agriculture is not a labor-intensive primary industry, but a new paradigm that includes cultivation, manufacturing and services. It is urgent to spread smart farm technology that can supply stable food with low labor force. In this paper, we review the current state of smart farm technology, analyze the impediments to diffusion, and present the direction of smart agricultural development in the future by upgrading ICT technology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.109-115
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• 2020

As the maritime targets that threaten allies become lower, smaller, and faster, the need for analysis and modeling of clutter according to sea state increases. Clutter according to the sea state has a great influence on radar performance, such as lowering the probability of detection of low-altitude small maritime targets. In this paper, to analyze the detection performance of a multi function radar for a ship, a sea clutter model suitable for the radar operating environment is selected from several sea clutter models, and analysis of low-altitude, small target detection under a clutter is performed. By using the actual data of the already mounted radar for maritime target detection, four known clutter models have been implemented for each sea state and compared with the actual data. Through this, by selecting a clutter model that best reflects the actual radar environment, reliability of the clutter model is improved. Subsequently, the selected model is used to detect the detectable distance to the low-altitude small target.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.4
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• pp.287-295
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• 2022

As low altitude long-range artillery threat has been strengthened, the development of anti-artillery interception system to protect assets against its attacks will be kicked off. We view the defense of long-range artillery attacks as a typical dynamic weapon target assignment (DWTA) problem. DWTA is a sequential decision process in which decision making under future uncertain attacks affects the subsequent decision processes and its results. These are typical characteristics of Markov decision process (MDP) model. We formulate the problem as a MDP model to examine the assignment policy for the defender. The proximity of the capital of South Korea to North Korea border limits the computation time for its solution to a few second. Within the allowed time interval, it is impossible to compute the exact optimal solution. We apply approximate dynamic programming (ADP) approach to check if ADP approach solve the MDP model within processing time limit. We employ Shoot-Shoot-Look policy as a baseline strategy and compare it with ADP approach for three scenarios. Simulation results show that ADP approach provide better solution than the baseline strategy.

• Journal of the Korean Society for Precision Engineering
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• v.4 no.2
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• pp.17-19
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• 1987

지난해 우리나라 경제는 안정속에 고도성장과 국제수지 흑자를 기록한 값진 보람을 느낀 한 해였다. 그러나 이같은 흑자기조는 개개기업의 성장잠재력에서 찾아볼 수도 있겠으나 대부분이 3저요인을 배경으로한 수출환경의 변화에 힘입은 바 크다. 그럼으로 언제 무산될지 모르는 장래를 낙관만 할 수는 없다. 지금의 현상을 어떻게 보는가에 대하여는 각계각층이 보는 시각에 따라 견해가 달라지겠으나 분명한 것은 국제유가나 국제이자가 오름세를 보이기 시작했다는 사실과 우리에게 국제경상수지흑자시대를 열어준 3저호재는 확실히 변해가고 있다는 것이다. 이렇게 볼 때 우리나라 경제는 해외요인변화에 매우 예민함으로 지금, 흑자기조가 정착되었다고 속단하기에는 너무 이른것 같다. 적어도 흑자기조가 정착되려면 모든 산업간, 계층간, 지역간의 불균형이 시정되고 기존의 산업기반을 내실화하는 단계에 있을 때 비로서 흑자경제의 향배가 가름하게 되는 것이다. 최근에 일어나고 있는 원화의 지속적인 평가절하, 엔화강세에 따른 원자재가격폭등은 우리에게 적지않은 위협을 주고있다. 이같은 상황에서 정부는 올해 국제수지흑자의 적정선유지를 위해 대미구매사절단의 파견, 수입선의 다변화, 수출지원정책의 감소등 다각적인 정책을 선택하고 있는 것으로써 일응 올바른 판단으로 수긍하나 다만 업종에 따른 특성에 배려가 있었으면 한다. 특히 우리나라의 기계공업은 20년의 짧은 근대화건설 과정에서 그나마 지금의 수준과 규모의 기반을 닦아왔다. 그러나 아직도 기술면에서 많은 취약점을 지니고 있어 대부분의 기초소재와 핵심부품이 해외에서 수입되고 있는 실정이다. 따라서 기계공업이 명실공히 선도산업으로써 의 위치를 굳히기 위해서는 적어도 기계류의 수입국에서 수출국으로의 탈바꿈을 할 때 비로소 성취될 것이며, 이 때가 관련산업간의 불균형이 시정된 흑자시대라고 보는 것이 옳을 것 같다. 작금의 주변환경은 서두에서 언급한 3저호재에 심상치 않는 조짐이 보이고 있다. 이같은 주변환경에 관점을 두고 지금 우리가 당면하고 있는 과제 중의 하나인 원화절상을 지적하지 않을 수 없다. 이같은 원화절상내용을 중심으로 부가적으로 수반된 몇가지의 현안문제와 함께 점검해 보기로한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.11
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• pp.1104-1111
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• 2009

In the low altitude, mission of the aircraft is restricted by a variety of threats such as anti-air missiles and terrain obstacles. Especially, aircraft have always a risk of ground collision near terrain. In this study, to effectively solve this problem, we developed the flight path generation algorithm that is considered the terrain avoidance. In this flight path generation algorithm, waypoints that should be passed by the UAV are selected first. The waypoints are located in the middle of the terrain obstacles. Then, physically meaningful waypoints sets are classified by Dijkstra algorithm. The optimal waypoint guidance law based on the optimal control theory is applied to produce trajectory candidates. And finally the minimum control energy trajectory is determined.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.117-124
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• 2018

This paper describes the localization development of an axial fan for KM-SAM multi-function radar. The multi-function radar, which is constantly affected by the external environment, is a key instrument for detecting and tracking low and medium altitude threat targets. Operating this equipment smoothly requires a fan for controlling the internal temperature and humidity. Presently, all such fans are imported. To solve these problems, localization development research was proposed. The development of localization includes analysis of requirements through review of related technical reports such as original equipment and system equipment specification, prototype design, and verification of design requirement through performance test and environmental test. The study results are described. The blower consisted of an axial fan with guide vanes and the motor was designed to generate a maximum airflow of 970 CFM and a wind pressure of 4.8 IWG. Six prototypes were manufactured for performance evaluation. In addition, for reliable data acquisition, AC power supply, fan performance tester and data acquisition equipment were designed and tested. All prototypes were verified as having design requirements equal to or better than those of imports.

• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.435-444
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• 2008

High energy charged particles are trapped by geomagnetic field in the region named Van Allen Belt. These particles can move to low altitude along magnetic field and threaten even low altitude spacecraft. Space Radiation can cause equipment failures and on occasions can even destroy operations of satellites in orbit. Sun sensors aboard Science and Technology Satellite (STSAT-l) was designed to detect sun light with silicon solar cells which performance was degraded during satellite operation. In this study, we try to identify which particle contribute to the solar cell degradation with ground based radiation facilities. We measured the short circuit current after bombarding electrons and protons on the solar cells same as STSAT-1 sun sensors. Also we estimated particle flux on the STSAT-l orbit with analyzing NOAA POES particle data. Our result clearly shows STSAT-l solar cell degradation was caused by energetic protons which energy is about 700keV to 1.5MeV. Our result can be applied to estimate solar cell conditions of other satellites.