• 한국항공우주학회지
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• 제41권7호
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• pp.569-576
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• 2013

군용항공기 산업의 비약적인 발전으로 정부의 군용항공기 감항인증은 점차적으로 중요한 역할을 차지하고 있다. 감항인증은 모든 항공기가 전 수명주기 동안 운용범위 내에서 비행안전에 적합하도록 항공기 개발에 필수적으로 요구되는 절차이다. 감항인증의 도입은 단일 수요자의 요구도에 부합되게 개발 해왔던 기존의 개발 사업특성에서 다수의 수요자의 공통의 요구도를 맞춘 개발 패러다임의 변화로 이끌어 가고 있다. 본 논문에서는 전투기급 항공기의 비행제어법칙의 감항인증 기준 설정에 대한 상세 연구와 감항인증 기술기준에 대한 입증 분석을 결과로 제시하였다.

• 한국항공우주학회지
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• 제44권6호
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• pp.484-491
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• 2016

본 연구의 목적은 항공기 메커니즘 구조물에 사용되는 금속 소재 토크바를 복합소재를 이용하여 무게절감이 가능한 구조물을 개발 하는것에 있다. 토크바에 주어진 하중조건 및 구조물의 설계 경계조건에 부합하는 유한요소모델을 이용하여 구조해석을 수행 하였다. 이를 바탕으로 최적화된 복합소재의 적층 조건 및 토크바의 두께 요건을 설정하였다. 설계요건에 맞게 제작된 시제품을 이용하여 복합소재 토크바의 비틀림 시험을 실시하였으며, 동구조 시험을 통해서 토크바의 강도 및 강성 요구조건을 만족한다는 것을 증명하였다.

• 구강회복응용과학지
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• 제20권2호
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• pp.143-150
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• 2004

Endosseous implants have been used to provide anchorage control in orthodontic treatment without the need for special patient cooperation. However these implants have limitation like space requirement, cost, equipments. Recently titanium micro-implant for orthodontic anchorage was introduced. Micro-implants are small enough to place in any area of the alveolar bone, easy to implant and remove, and inexpensive. In addition, orthodontic force application can begin almost immediately after implantation. The mandibular first, maxillary first, mandibula second, and maxillary second molars were the four most commonly missing teeth in adult sample. In case of posterior molar teeth missing, deflective contacts in any position, over time, has produced pathologic change of occlusal scheme because of extrusion of opposing teeth. This case had interocclusal space deficiency by mandibular right molars missing over time. The micro-implants had been used for intrusion of maxillary right molars for interocclusal space. The micro-implant would be absolute anchorage for orthodontic movement. Therefore, the micro-implant would be effective method for correction of occlusal plane.

• Journal of Astronomy and Space Sciences
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• 제16권2호
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• pp.177-190
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• 1999

An absorbed heat-flux method for ground simulation of on-orbit thermal environment of satellite is addressed in this paper. For satellite ground test, high vacuum and extremely low temperature of deep space are achieved by space simulation chamber, while spatial environmental heating is simulated by employing the absorbed heat-flux method. The methodology is explained in detail with test requirement and setup implemented on a satellite. Developed heat-load control system is presented with an adjusted PID-control logic and the system schematic realized is shown. A practical and successful application of the heat simulation method to KOMPSAT(Korea Multi-purpose Satellite)thermal environmental test is demonstrated, finally.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1553-1557
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• 2005

High performance and reliability of the storage system to handle a very large amount of data has been become very important. Many techniques have been applied on the various application systems to establish very large capacity storage that satisfy the requirement of high I/O speed and physical or logical failure protection. We applied RAID and LVM to construct a storage system for the global data center which needs a very reliable large capacity storage system. The storage system is successfully established and equipped on the latest Linux application server.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 2005년도 추계학술대회 발표 논문집
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• pp.349-358
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• 2005

Recently, developing U-City as an integrated set of ubiquitous spaces has been regarded as a promising field in realizing ubiquitous computing technology. However, well-organized requirement analyses of U-City to declare what kinds of ubiquitous space services are needed and which ubiquitous computing technology should be incorporated to come up with the needs are still insufficient. Hence, the aims of this Paper are to Propose a set of unique U-City construction philosophies and to analyze which services Should be offered in the ubiquitous Space services in U-Cities. A field survey to the citizens who are potential end users of the ubiquitous space services was conducted to analyze the success factors of U-City using CSF methodology. Focused group interview with professionals in the field of ubiquitous computing technology in Korea was then performed to identify the relationship of the ubiquitous space services and the critical success factors.

• International Journal of Aeronautical and Space Sciences
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• 제18권3호
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• pp.579-587
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• 2017

Spaceborne cryocoolers produce undesirable micro-vibration disturbances during their on-orbit operation, which are a primary source of image-quality degradation for high-resolution observation satellites. Therefore, to comply with the strict mission requirement of high-quality image acquisition, micro-vibration disturbances induced by cooler operation have always been subjected to an isolation objective. However, in this study, we focused on the applicability of energy harvesting technology to generate electrical energy from micro-vibration energy of the cooler and investigated the feasibility of utilizing harvested energy as a power source to operate low-power-consumption devices such as micro-electromechanical system (MEMS) devices. A tuned mass damper (TMD)-type electromagnetic energy harvester combined with a conventional passive vibration isolator was proposed to achieve this objective. The system performs the dual functions of electrical energy generation and micro-vibration isolation. The effectiveness of the strategy was evaluated through numerical simulations.

• 한국항공우주학회지
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• 제39권10호
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• pp.946-951
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• 2011

본 논문에서는 제주 국제 공항에서 실시된 항공우주연구원의 비행 실험 데이터를 기반으로 항공기 착륙 상황을 시뮬레이션하고, Protection Level 관점에서 제주 국제 공항 GBAS 시스템의 가용성 및 성능 향상을 위한 요구조건을 분석하였다. 요구조건을 분석하기위해, CAT I, CAT II/III의 결심고도에서 항공기 착륙 상황 (기준국 정밀좌표, 항공기 착륙 속도, 기준국 및 항공기 안테나 성능지표 등)을 Protection Level 계산에 적용하였다. 이 때 귀무가설 / 대립가설 (H0 / H1) Protection Level을 한계치 (Alert Limit)와 비교 분석하여, 현재 CAT I, CAT II/III의 가용도 및 개선 방향을 도출하였다.

• 한국정보전자통신기술학회논문지
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• 제11권1호
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• pp.12-17
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• 2018

본 연구는 디지털위성중계기용 SHF 대역 안테나의 설계 및 구현에 대해 기술하였다. SHF 대역 안테나는 반사판, Septom Polarizer, Feed Horn 및 지지대 등으로 구성된다. 제작 전 우주환경에 대한 사전 시뮬레이션 분석을 통하여 장비 오동작 가능성을 최소하였으며, 발사환경 시 발생하는 진동에 대한 시뮬레이션을 통해 신뢰성 있는 안테나를 설계하였으며, 제작 후 주요 성능지표에 대해 만족여부 확인 및 사전 성능 시뮬레이션 결과와 비교하였다. 안테나를 제작 후 안테나 주빔의 최대이득은 36.5dBi 로 요구조건인 35dBi 이상을 만족하며, 반사손실에 대해서도 최대 -24dB 이하로 요구조건 -20dB를 만족한다. 또한 안테나의 송수신 격리도에 대해서도 -22.6dB 이하로 요구조건 -20dB 이하를 만족한다. 본 논문에 기술한 위성 중계기용 안테나는 고신뢰성이 요구되는 정지궤도 및 저궤도 위성분야에 향후 활용이 가능하다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.109-113
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• 2007

The COMS provides the LRIT/HRIT services to users. The COMS LRIT/HRIT broadcast service should satisfy the 15 minutes timeliness requirement. The requirement is important and critical enough to impact overall performance of the LHGS. HRIT image data is acquired from INRSM output receiving but LRIT image data is generated by sub-sampling HRIT image data in the LHGS. Specially, since LRIT is acquired from sub-sampled HRIT image data, LRIT processing spent more time. Besides, some of data loss for LRIT occurs since LRIT is compressed by lossy JPEG. Therefore, algorithm with the fastest processing speed and simplicity to be implemented should be selected to satisfy the requirement. Investigated sub-sampling algorithm for the LHGS were nearest neighbour algorithm, bilinear algorithm and bicubic algorithm. Nearest neighbour algorithm is selected for COMS LHGS considering the speed, simplicity and anti-aliasing corresponding to the guideline of user (KMA: Korea Meteorological Administration) to maintain the most cloud itself information in a view of meteorology. But the nearest neighbour algorithm is known as the worst performance. Therefore, it is studied in this paper that the selection of nearest neighbour algorithm for the LHGS is reasonable. First of all, characteristic of 3 sub-sampling algorithms is studied and compared. Then, several sub-sampling algorithm were applied to MTSAT-1R image data corresponding to COMS HRIT. Also, resized image was acquired from sub-sampled image with the identical sub-sampling algorithms applied to sub-sampling from HRIT to LRIT. And the difference between original image and resized image is compared. Besides, PSNR and MSE are calculated for each algorithm. This paper shows that it is appropriate to select nearest neighbour algorithm for COMS LHGS since sub-sampled image by nearest neighbour algorithm is little difference with that of other algorithms in quality performance from PSNR.