• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.249-250
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• 2008

본 연구는 전년도 지형참조항법(TRN; Terrain Referenced Navigation)에 근거하는 3-D 헬리콥터 항법 시스템을 위한 알고리즘 개발의 후속 연구로서 실용적 완성을 위해 수행되었다. 본 연구에서 헬리콥터의 위성항법장치(GPS)로부터의 정보(X,Y,Z 좌표)는 자동차가 도로주행중 매 1초 간격으로 수신되는 GPGGA Code로 대체되었다. 비행체는 3차원 직교 좌표 체계(Cartesian coordinate system)로 표현되는 수치지형모델(DTM; Digital Terrain Model)상에서 시점(Origination)-종점(Destination) 분석 기법에 의해 항로를 결정한다. 본 시스템은 우선 조종사에게 지형의 사전 인식을 위해 시점-종점 주변 3차원 지형도와 항로의 종단면도를 보여준다. 본 시스템은 직접적인 지상 충돌을 피하기 위해 지형 여유 층면(Terrain Clearance Floor)의 개념을 도입, 기복 지형 표면에 일정 높이의 완충 공간을 설정한다. 본 시스템은 매초 GPS로부터 실시간 수신되는 X,Y,Z 위치와 DTM상의 x,y,z를 비교하여 만약 비행체가 완충 공간에 접근하게 되면 즉시 경고음과 메시지를 발한다. 수치지형모델은 (주)첨성대가 확보하고 있는 3초 간격의 DTM을 채택, 작성하였다.

• Journal of Wind Energy
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• v.14 no.4
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• pp.75-86
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• 2023

We observed five species and 163 individuals of birds in the Demonstration Offshore Wind Farm in the southern part of the West Sea in Korea, and 33 species and 4,023 individuals from Gusipo to Dongho Beach. The most dominant bird in both areas was the black-tailed gull, Larus crassirostris. The flight height of birds for collision risk (wind turbine and bird) was divided into two groups. First, the safe height was from sea level to 20 m (< 20 m), with no effect from the action of revolving blades. Second, the danger height was more than 20 m from sea level (> 20 m), with a collision risk from the action of revolving blades. Birds flying a safe height (< 20 m) were 83.9% (271 individuals) and danger height (> 20 m) were 16.1% (52 individuals). Also, 11.7% of birds (35 individuals) used the inside of the Demonstration Offshore Wind Farm as a habitat for foraging and resting, and 88.3% birds used the outside. We suggest that the risk of collision with the wind farm was low due to the relatively low flight height of birds and distance between wind turbines (> 800 m).

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.77-87
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• 2008

This study is to formulate strategy for subject who are selected as national team in horizontal bars event in apparatus gymnastics. For this, skill training program was applied to players for 8 weeks. Then it was analyzed by using 3D motion Analysis system to seek the difference between before and after using the program. There were decisive demerit element K's first try for Tkatchev stretched movement from low elevation and crooked body while elevating. Not only, the location of his center of mass is far and low and there was some concern in his landing due to bended his hip-joint, but also, it exposed weak point in retro-action followed technique. Thus, to overcome that weak point, the subject repeated practices on following; when preparing for Tkatchev stretched movement at downward for big spin, make sure extend shoulder angle faster, make sure Tap movement is short and concise using hip-joint angular while delaying Tap timing for folding the body, and moreover, while backlashing the body, used shoulder joint angle wide to pull up the body. As a result, the speed of vertical upward did rut increase when separation from the bar. However, height of elevation increased that the leg would rut hit the horizontal bar even straight up the hip-joint. Therefore, the movement itself provided magnificent motion and even helped decrease the demerits.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.1
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• pp.49-62
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• 2005

The VR (virtual reality) simulator such as helicopter simulation needs virtual environment of existing urban area. But the real urban environment keeps changing. We need a modeling method to make use of the GIS data that are updated periodically. The flight simulation needs to visualize not only buildings in near distance but also a large number of buildings in the far distance. We propose a method for modeling urban environment from aerial image and digital map with a comparatively small manual work. Image based modeling is applied to urban model which considers the characteristic of Korean cities. Buildings in the distance can be presented without creating a lot of polygons. Proposed method consists of the pre-processing stage which prepares the model from the GIS data and the modeling stage which makes the virtual urban environment. The virtual urban environment can be modeled with the simple process which utilizes the height map of buildings.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.3
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• pp.78-95
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• 2011

This study has developed various DEMs with different spatial resolutions using many different interpolation methods with the aid of a 1:5,000 digital map. In addition, this study has evaluated the vertical accuracy of various DEMs constructed by check point data obtained from the network RTK GPS survey. The obtained results suggest that a DEM developed from the TIN-based Terrain method performs well in evaluating height restriction of buildings in a flying safety area considering general RMSE values, land-type RMSE values and profile evaluation results, etc. And, it has been found that three meters is the right spatial resolution for a DEM in evaluating height restriction of buildings in a flying safety area. Meanwhile, elevation values obtained by the DEM are not point estimation values but interval estimation values. This can be used to check whether the height of buildings in the vicinity of an airfield violates height limitation values of the area. To check whether the height of buildings measured in interval estimation values violates height limitation values of the area, this study has adopted three steps: 1) high probability of violation, 2) low probability of violation, 3) inconclusiveness about the violation. The obtained results will provide an important basis for developing a GIS related to the evaluation of height restriction of buildings in the vicinity of an airfield. Furthermore, although results are limited to the study area, the vertical accuracy values of the DEM constructed from a two-dimensional digital map may provide useful information to researchers who try to use DEMs.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.1
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• pp.63-101
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• 2020

'Flight safety zone' means a zone that the Minister of National Defense designates under Articles 4 and 6 of the Protection of Military Bases and Installations Act (hereinafter 'PMBIA') for the safety of flight during takeoff and landing of military aircrafts. The purpose of flight safety zone is to contribute to the national security by providing necessary measures for the protection of military bases and installations and smooth conduct of military operations. In this case, when the state set and used the flight safety zone, the landowner claimed restitution of unjust enrichment against the country. This article is an analysis based on the existing legal theory regarding the legitimacy of plaintiff's claim, and the summary of the discussion is as follows. A person who without any legal ground derives a benefit from the property or services of another and thereby causes loss to the latter shall be bound to return such benefit (Article 741 of the Civil Act). Since the subject matter is an infringing profit, the defendant must prove that he has a legitimate right to retain the profit. The State reserves the right to use over the land designated as a flight safety zone in accordance with legitimate procedures established by the PMBIA for the safe takeoff and landing of military aircrafts. Therefore, it cannot be said that the State gained an unjust enrichment equivalent to the rent over the land without legal cause. Expropriation, use or restriction of private property from public necessity and compensation therefor shall be governed by Act: provided, that in such a case, just compensation shall be paid (Article 23 (1) of the Constitution of The Republic of KOREA). Since there is not any provision in the PMBIA for loss compensation for the case where a flight safety zone is set over land as in this case, next question would be whether or not it is unconstitutional. Even if it is designated as a flight safety zone and the use and profits of the land are limited, the justification of the purpose of the flight safety zone system, the appropriateness of the means, the minimization of infringement, and the balance of legal interests are still recognized; thus just not having any loss compensation clause does not make the act unconstitutional. In conclusion, plaintiff's claim for loss compensation based on the 'Act on Acquisition of and Compensation for land, etc. for Public Works Projects', which has no provision for loss compensation due to public limits, is unjust.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.6
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• pp.467-478
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• 2020

Hypervisor virtualize hardware resources to utilize them more effectively. At the same time, hypervisor's characteristics of time and space partitioning improves reliability of flight software by reducing a complexity of the flight software. Korea Aerospace Research Institute chooses one of hypervisors for space, XtratuM, and examine its applicability to the flight software. XtratuM has strong points in performance improvement with high reliability. However, it does not support SMP. Therefore, it has limitation in using it with high performance applications including satellite altitude orbit control systems. This paper proposes RTEMS XM-SMP to support SMP with RTEMS, one of real time operating systems for space. Several components are added as hypercalls, and initialization processes are modified to use several processors with inter processors communication routines. In addition, all components related to processors are updated including context switch and interrupts. The effectiveness of the developed RTEMS XM-SMP is demonstrated with a GR740 board by executing SMP benchmark functions. Performance improvements are reviewed to check the effectiveness of SMP operations.

• Korean Journal of Remote Sensing
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• v.36 no.5_4
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• pp.1209-1220
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• 2020

In the case of forest areas, the installation of ground control points (GCPs) and the selection of terrain features, which are one of the unmanned aerial photogrammetry work process, are limited compared to urban areas, and safety problems arise due to non-visible flight due to high forest. To compensate for this problem, the drone equipped with a real time kinematic (RTK) sensor that corrects the position of the drone in real time, and a 3D flight method that fly based on terrain information are being developed. This study suggests to present a method for investigating damage using drones in forest areas. Position accuracy evaluation was performed for three methods: 1) drone mapping through GCP measurement (normal mapping), 2) drone mapping based on topographic data (3D flight mapping), 3) drone mapping using RTK drone (RTK mapping), and all showed an accuracy within 2 cm in the horizontal and within 13 cm in the vertical position. After evaluating the position accuracy, the volume of the landslide area was calculated and the volume values were compared, and all showed similar values. Through this study, the possibility of utilizing 3D flight mapping and RTK mapping in forest areas was confirmed. In the future, it is expected that more effective damage investigations can be conducted if the three methods are appropriately used according to the conditions of area of the disaster.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.597-604
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• 2016

The aim of this study was to prevent the decrease in crop output by disease and insect pests and excessive spraying of agricultural pesticides by application uniformity. A 3m height and 15km/h speed is difficult to maintain with an unmanned helicopter for aerial application, which has been affected by the controlling habits and methods or environmental factors, such as changes in the wind. Therefore, in this study, an aerial application system was design to be attached to an unmanned helicopter, which can allow a controlled application width and spray rate automatically and verified experimentally using Rmax of MS-AVIATION. The size of agricultural land was 50 m2 and nine water sensitive cards were arranged at 1.25m intervals in 5 rows with each row having a 10m interval from the position of 5m. The unmanned helicopter was flying at speeds ranging from 7.2km/h to 17.6km/h and heights ranging from 2.32m to 3.47m. The proposed aerial application system allowed application uniformity by making a valid spraying area of 7.5 m2 with 46423 particles distributed on average.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.125-131
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• 2004

최근 급속한 도시화와 국토개발에 의해 대규모의 사회기반시설이 확충되면서 각종 재해와 환경오염이 우리의 생활환경을 위협하고 있다. 따라서 체계적이고 효율적으로 시설물을 관리하기 위한 핵심기술로서의 GIS는 정보화시대에서 그 활용성이 높이 평가되고 있다. 이러한 지리 정보시스템에 비디오 데이터 연계 기능을 더하여 영상을 기반으로 직접 사용자와 상호작용을 하며 공간 데이터를 분석, 관리, 출력하는 비디오 지리 정보 시스템(Video Geographic Information System: Video GIS)이 GIS 분야에 있어서 새로운 연구 분야로 떠오르고 있다. 본 연구에서는 급변하는 도시지역의 시설물들을 실시간적으로 관리를 하기 위해 비행선촬영시스템을 통하여 취득된 비디오 자료를 데이터베이스화하고 이를 공간정보와 연계시켜 도시지역에 존재하는 각종 시설물을 관리할 수 있는 동영상 정보시스템을 prototype으로 구축하여 그 가능성을 제시하였다.