• 한국항공우주학회지
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• 제43권6호
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• pp.488-496
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• 2015

본 연구에서는 각각 다른 목적지에서 다수의 임무를 수행해야하는 복수 무인항공기(Unmanned Aerial Vehicle, UAVs)의 경로를 결정할 때, 무인항공기의 생존가능성을 고려하여 경로를 결정하는 프레임워크를 제안하였다. 본 라우팅 문제는 무인항공기 안전과 임무 완료시간 간의 trade-off 를 나타내는 비용 매트릭스를 이용한 차량경로문제(Vehicle Routing Problem, VRP)로 정의할 수 있다. 특정위치에서 무인항공기의 위험 레벨은 감지될 확률과 격추될 확률을 고려하여 모델링 하였고, 위협 레벨과 비행거리를 고려한 두 지역간의 최소비용경로는 육각형격자(Hexagonal cells)에서 Dijkstra 알고리듬을 사용하여 결정하였다. 또한, 지속적으로 다수의 적을 감시 정찰하는 임무를 수행하는 복수 무인항공기의 최적경로를 결정하는 case study를 수행하였으며, 그 결과를 논의하였다.

• 항공우주시스템공학회지
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• 제17권2호
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• pp.78-85
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• 2023

다수 무인기 체계에서 임무할당은 임무 수행 능력을 결정하는 중요한 요인이다. 본 논문은 유전 알고리즘에 기반한 임무계획기법을 제안한다. 본 기법을 통해 제한 조건을 만족하면서, 임무 완료 시간을 최소화하는 해를 구할 수 있다. 임무 할당 문제의 최적해를 구하기 위해서는 계산량이 많이 필요하므로 본 기법이 해를 구하는 대안이 될 수 있다. 본 기법은 현실 세계의 다양한 종류의 무인기, 임무, 제한 조건을 고려하였다. 제안된 기법은 각 무인기의 임무 시퀀스와 제한 조건 만족을 위한 임무 별 대기 시간을 도출한다. 다양한 수치적 시뮬레이션 결과를 통해 임무 종료 시간을 최소화하는 임무계획 기법의 성능을 확인하였다.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제11권3호
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• pp.61-73
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• 2005

Recently, Korea is becoming a world-leading country in various industrial fields with it's advanced information technology. In the 20th century, Korea went through a chaotic period from Japanese colonization via the Korean war to IMF because of lack of globalization. Now, we have a mission and the abilities to lead world-wide trends in entire fields of society. This study, comparing the modern healthcare planning trends in Korea, China, Japan and the United States, proposes the Northeast Asia Healthcare Network Plan which Korea leads. United States is the starter of healthcare network, but it's location is too far from Asia and IT is also inferior to the Korean. Japan seems to have no concerns with this healthcare network. And the current China is a rapid growing period and is too much for building its domestic healthcare infra-structure. they still have no concerns with re-structuring of healthcare system and facilities. Because of these reasons, I think Korea should have to lead Northeast Asia Healthcare network.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.387-392
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• 1998

To establish a monthly data collection planning for the Ocean Scanning Multispectral Imager (OSMI), we have examined the global patterns of three impacting factors: pigment concentration, cloud cover, and sun glint. Other than satellite mission constraints (e.g., duty cycle), these three factors are considered critical for the OSMI data collection. The Nimbus-7 Coastal Zone Color Scanner (CZCS) monthly mean products and the International Satellite Cloud Climatology Project (ISCCP) monthly mean products (C2) were used for the analysis of pigment concentration and cloud cover distributions, respectively. And the monthly simulated patterns of sun glint were produced by performing the OSMI orbit prediction and the calculation of sun glint radiances at the top-of-atmosphere (TOA). Using monthly statistics (mean and/or standard deviation) of each factor in the above for a given 10$^{\circ}$ latitude by 10$^{\circ}$ longitude grid, we generated the priority map for each month. The priority maps of three factors for each month were subsequently superimposed to visualize the impact of three factors in all. The initial results illustrated that a large part of oceans in the summer hemisphere was classified into the low priority regions because of seasonal changes of clouds and sun illumination. Sensitivity tests were performed to see how cloud cover and sun glint affect the priority determined by pigment concentration distributions, and consequently to minimize their seasonal effects upon the data collection planning.

• 한국군사과학기술학회지
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• 제15권4호
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• pp.424-434
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• 2012

This paper presents a path planning algorithm of the unmanned aerial vehicle for the neutralization of the enemy firepower. The long range firepower of the ememy is usually located at the rear side of the mountain which is difficult to bomb. The path planner not only consider the differential constraints of the Unmanned Aerial Vehicle (UAV) but also consider the final approaching angle constraint. This problem is easily solved by incorporating the analytical upper bounded continuous curvature path smoothing algorithm into the Rapidly Exploring Random Tree (RRT) planner. The proposed algorithm can build a feasible path satisfying the kinematic constraints of the UAV on the fly. In addition, the curvatures of the path are continuous over the whole path. Simulation results show that the proposed algorithm can generate a feasible path of the UAV for the bombing mission regardless of the posture of the tunnel.

• Advances in aircraft and spacecraft science
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• 제4권3호
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• pp.237-267
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• 2017

Automatic trajectory re-planning is an integral part of unmanned aerial vehicle mission planning. In order to be able to perform this task, it is necessary to dispose of formulas or tables to assess the flyability of various typical flight segments. Notwithstanding their importance, there exist such data only for some particularly simple segments such as rectilinear and circular sub-trajectories. This article presents an analysis of a new, very efficient, way for an airplane to fly on an inclined circular trajectory. When it flies this way, the only thrust required is that which cancels the drag. It is shown that, then, much more inclined trajectories are possible than when they fly at constant speed. The corresponding equations of motion are solved exactly for the position, the speed, the load factor, the bank angle, the lift coefficient and the thrust and power required for the motion. The results obtained apply to both types of airplanes: those with internal combustion engines and propellers, and those with jet engines. Conditions on the trajectory parameters are derived, which guarantee its flyability according to the dynamical properties of a given airplane. An analytical procedure is described that ensures that all these conditions are satisfied, and which can serve for producing tables from which the trajectory flyability can be read. Sample calculations are shown for the Cessna 182, a Silver Fox like unmanned aerial vehicle, and an F-16 jet airplane.

• Archives of Plastic Surgery
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• 제44권3호
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• pp.217-222
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• 2017

Background The prevalence of flap necrosis after palatoplasty in patients with cleft palate. The prevalence of mucoperiosteal flap necrosis after palatoplasty remains unknown, and this complication is rare. This event is highly undesirable for both the patient and the surgeon. We present here a new scale to evaluate the degree of hypoplasia of the palate and identify patients with cleft palate at high risk for the development of this complication. Methods In this case series, a 20-year retrospective analysis (1994-2014) identified patients from our records (medical records and screening day registries) with nonsyndromic cleft palate who underwent operations at 3 centers. All of these patients underwent operations using 2-flap palatoplasty and also underwent a physical examination with photographs and documentation of the presence of palatal flap necrosis after primary palatoplasty. Results Palatal flap necrosis was observed in 4 cases out of 1,174 palatoplasties performed at these centers. The observed prevalence of palatal flap necrosis in these groups was 0.34%. Conclusions The prevalence of flap necrosis can be reduced by careful preoperative planning, and prevention is possible. The scale proposed here may help to prevent this complication; however, further studies are necessary to validate its utility.

• Journal of Astronomy and Space Sciences
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• 제19권3호
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• pp.197-206
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• 2002

NORAD Two Line Elements (TLE) are widely used for the increasing number of small satellite mission operations and analysis. However, due to the irregular periodicity of generation of the NORAD TLE, a new TLE that is independent of NORAD is required. A TLE type Orbit Determination (TLEOD) has been developed for the generation of a new TLE. Thus, the TLEOD system can provide an Antenna Control Unit (ACU) with the orbit determination result in the type of a TLE, which provides a simple interface for the commercialized ACU system. For the TLEOD system, NORAD SGP4 was used to make a new orbit determination system. In addition, a least squares method was implemented for the TLEOD system with the GPS navigation solutions of the KOMPSAT-1. Considering both the Orbit Propagation (OP) difference and the tendency of $B^{*}$ value, the preferable span of the day in the observation data was selected to be 3 days. Through the OD with 3 days observation data, the OP difference was derived and compared with that of Mission Analysis and Planning (MAPS) for the KOMPSAT-1. It has the extent from 2 km after sit days to 4 km after seven days. This is qualified enough for the efficiency of an ACU in image reception and processing center of the KOMPSAT-2.

• International Journal of Aeronautical and Space Sciences
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• 제12권3호
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• pp.283-287
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• 2011

Science and Technology Satellite-3 (STSAT-3) is a 150 kg class micro satellite based with the national space program. The STSAT-3 system consists of a space segment, ground segment, launch service segment, and various external interfaces including additional ground stations to support launch and early operation phases. The major ground segment is the ground station at the Satellite Technology Research Center, Korea Advanced Institute of Science and Technology site. The ground station provides the capability to monitor and control STSAT-3, conduct STSAT-3 mission planning, and receive, process, and distribute STSAT-3 payload data to satisfy the overall missions of STSAT-3. The ground station consists of the mission control element and the data receiving element. This ground station is designed with the concept of low cost and high efficiency. In this paper, the requirements and design of the ground station that has been developed are examined.

• 한국군사과학기술학회지
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• 제16권1호
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• pp.5-26
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• 2013

Since the optimized use of sonar systems for target tracking is a practical problem for naval operations, the measure of mission achievability is needed for preparing efficient sonar-maneuver tactic. In order to quantify the mission achievability or Measure Of Effectiveness(MOE) for given sonar-maneuver tactics, we developed and tested a simulation algorithm. The proposed algorithm for tracking is based on Measure Of Performance(MOP) for localization and tracking system of sonar against target. Probability of Detection(PD) using steering beam patterns referenced to the aspect angle of sonar is presented to consider the tracking-performance of sonar. Also, the integrated software package, named as Optimal Acoustic Search Path Planning(OASPP) is used for generating sonar-maneuver patterns and vulnerability analysis for a given scenario. Through simulation of a simple case for which the intuitive solution is known, the proposed algorithm is verified.