• Digital Contents
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• no.5 s.72
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• pp.54-60
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• 1999

현재 전세계적으로 진행중인 지식관리시스템에 관한 논의는 인터넷의 발전 방향과 함께 전개되고 있다. 이 글에서는 인터넷과 지식경영, 좀더 구체적으로는 웹과 지식관리시스템의 관계에 대해서 살펴보고 그 전개방향에 대해 예측하고자 한다.

• Journal of Aerospace System Engineering
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• v.12 no.6
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• pp.58-65
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• 2018

The dynamic characteristics of the deployable composite parabolic reflector with several panels were numerically and experimentally investigated. The deployment mechanism is designed to efficiently fit in a small volume. The parameters guiding the deployment are determined by considering; the number of panels, folding/twisting angles, and the driving forces of actuating devices. The panels are fabricated using carbon fiber reinforced plastics (CFRPs). The zero-gravity simulator is manufactured for the unfolding test. The deployment behaviors of the reflector are finally observed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.2
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• pp.164-171
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• 2002

In this study, a mass-spring model is used to dynamically describe and calculate the shape and movement of a mid-water trawl system. This mathematical model theorizes that the factors constituting the system are the material points and the external forces such as hydrodynamic load, gravity, and buoyancy act on these material points. In addition, it surmises that these material points are connected to each other by springs, the springs do not have any mass, and the internal force acts on these springs. The non-linear differential equations are implicitly integrated with time for guaranteeing a stable solution. The dynamic simulation by the mass-spring model shows the status of the gear such as fishing gear depth, distance between doors, shape of the gear, and tension of each line. It depends on the parameters such as towing force, warp length, force of a sinker, buoyancy of a float, type of door and netting materials. The validity of the model is verified by comparing simulation motions of a trawl system obtained from computed values to those from an actual experiment.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.136.1-136.1
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• 2012

저궤도지구관측 위성의 태양전지판은 위성이 궤도에 진입하고나서 전개된 후 위성에 전력을 공급하는 임무를 전담하는 중요 시스템이다. 이러한 시스템이 정상적인 임무 수행을 위해서는 우주 환경에서의 원활한 전개가 필수적이다. 따라서 위성은 발사이전 개발과정에서 태양전지판에 대한 전개성이 완벽히 검증되어야 한다. 이를 위해 무중력 조건을 모사하는 별도의 시험 장치를 활용하여 태양전지판의 전개 시험이 실시된다. 본 논문에서는 저궤도지구관측위성용 태양전지판의 비행모델에 대하여 실시한 전개 시험 방법 및 분석 내용을 소개하고자한다.

• Journal of Digital Contents Society
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• v.9 no.1
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• pp.87-99
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• 2008

High Altitude Platform network systems utilize Unmanned Aerial Vehicle as routers for ground node communication. For this purpose, geographical clustering of ground nodes must be required. In this paper, we assume mobile ground nodes over wide area and the clusters composed of ground nodes are identified. UAVs can be positioned at the point of centroid of clusters. The number of UAVs are derived from the area size and the number of ground nodes deployed in that area. From the simulation and application of clustering algorithms, we showed visual clustering results with dynamic variance of number of ground nodes.

• Satellite Communications and Space Industry
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• v.8 no.1 s.18
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• pp.138-151
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• 2000

본 원고는 ITS 구축에 따른 정보통신의 역할, 통신망 접속구조와 전송규격, 표준화 활동과 서비스 요구사항을 해석하고 국내의 ITS전개와 구축현황을 조사하여 정리하였다. 그리고 차세대 ITS 시스템의 전개와 무선 패킷 통신기술의 개발의 필요성과 ITS 접근전략의 제약요인을 기술하였다.

• Journal of Aerospace System Engineering
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• v.16 no.5
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• pp.86-93
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• 2022

Generally, a deployable solar panel is used primarily to achieve sufficient power output to perform the mission. However, temperature distribution on the antenna reflector may increase due to the shading effect induced by the presence of the deployable solar panels. Appropriate thermal design is critical to minimize the thermal deformation of the mesh antenna reflector in harsh on-orbit thermal environments to ensure remote frequency (RF) performance. In this paper, we proposed a dual-surface primary reflector consisting of a mesh antenna and a flexible fabric membrane sheet. This design strategy can contribute to thermal stabilization by using a flexible solar panel on the rear side of membrane sheet to reduce the temperature distribution caused by the deployable solar panel. The effectiveness of the mesh antenna design strategy investigates through on-orbit thermal analysis.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.78-86
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• 2019

This paper describes the stiffness optimization of the torsion spring hinge of the large SAR antenna considering the deployment performance. A large SAR antenna is folded in a launch environment and then unfolded when performing a mission in orbit. Under these conditions, it is very important to find the proper stiffness of the torsion spring hinge so that the antenna panels can be deployed with minimal impact in a given time. If the torsion spring stiffness is high, a large impact load at the time of full deployment damages the structure. If it is weak, it cannot guarantee full deployment due to the deployment resistance. A multi-body dynamics analysis model was developed to solve this problem using RecurDyn and the development performance were predicted in terms of: development time, latching force, and torque margin through deployment analysis. In order to find the optimum torsion spring stiffness, the deployment performance was approximated by the response surface method (RSM) and the optimal design was performed to derive the appropriate stiffness value of the rotating springs.

• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.63-72
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• 2022

The purpose of this paper was to understand the dynamics of deployment of large mesh antennas, and to provide a numerical method for determining the dynamic stiffness and the driving forces for the design. The deployment structure was numerically modeled using the frame elements. The eigenvalue analysis was demonstrated, with respect to the folded and unfolded configurations of the antenna. A multibody dynamic model was formulated with Kane's equation, and simulated using the pseudo upper triangular decomposition (PUTD) method for resolving the constrained problem. Based on the multibody model, the kinetics of the deployment, the motor driving forces, and the feasibility of the designed deployment structure were investigated.

• Journal of the Korean Institute of Intelligent Systems
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• v.6 no.4
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• pp.3-9
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• 1996

본 논문에서는 Boole 함수를 기호 다치 논리 함수로 확장하여 법-M(Modulus-M)의 수체계를 기본으로 하는 기호 다치 논리 함수에 대한 MacLaurin 전개의 구조적 성질을 분석한다. 그리고 기호 다치 변수의 상태 변화에 따라 이에 사상된 퍼지 규칙을 자동 생성할 수 있는 기법을 제안한다. 또한 이러한 이론과 성질을 기존의 퍼지 추론 기능과 결합하여 동적인 상태 변화에 적응할 수 있는 퍼지 추론 시스템 설계방법을 제안한다.