• Current Applied Physics
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• v.18 no.11
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• pp.1388-1392
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• 2018

Metal thin films are used widely to solve the vibration problem. However, damping mechanism is still not clear, which limits the further improvement of the damping properties for film and the development of multi-functional damping coating. In this paper, Damping microscopic mechanism of porous metal films was investigated at both macroscopically and microscopically mixed levels. Molecular dynamics simulation method was used to model and simulate the loading-unloading numerical experiment on the micro-pore and vacancy model to get the stress-strain curve and the microstructure diagram of different defects. And damping factor was calculated by the stress-strain curve. The results show that dislocations and new vacancies appear in the micro-pores when metal film is stretched. The energetic consumption from the motion of dislocation is the main reason for the damping properties of materials. Micro-mechanism of damping properties is discussed with the results of in-situ experiment.

• Structural Engineering and Mechanics
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• v.33 no.6
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• pp.781-784
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• 2009

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.9
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• pp.747-754
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• 2013

This paper describes SCTE(System and Control unit Test Equipment) as an integrated test equipment for airborne SAR system and control unit. SCTE enhances reusability of test equipment by modular design for required functions and strengthens automatic testing and test convenience by providing functions such as script-based testing function and report generation function. Also, it includes a navigation data simulator which can simulate various flight conditions. In this paper, we details SCTE requirements, H/W and S/W design, implementation, and test results with control unit and SAR system.

• Structural Engineering and Mechanics
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• v.33 no.2
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• pp.257-260
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• 2009

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.2
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• pp.147-154
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• 2021

In this paper, the configuration and design of the test equipment are presented to examine the impact of rapid temperature change in cooling-air that may occur during the operation of the fixed wing aircraft Environmental Control System (ECS) on avionic electronic equipment. At the start of the ECS, the temperature of the air supplied by the aircraft ECS may be increased to 5.0℃ per second. In order to ensure operating of the avionic electronic equipment that is mounted on the aircraft and receives cooling-air from the ECS, testing equipment that can implement the cooling-air characteristic test environment is required. During design of test equipment was verified cooling-air rapid rate of temperature change by performing a thermal/flow analysis, performance of the test equipment implemented was verified by applying an avionic electronic equipment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.2
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• pp.187-192
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• 2009

Telecommand & telemetry control equipment is needed for the testing of the transponders during the development of satellite. This equipment must have a loopback function to perform the self testing without satellite. The fabrication of the designed system is easier and cheaper than the conventional testing system using direct modulation method. The measured results of fabricated equipment are satisfied with required specifications. A overall path loss of uplink and downlink is 47.8 dB and 42.6 dB, respectively. Also, IMD3 of uplink has measured 60.68 dBc at an output of -50 dBm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.10
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• pp.849-858
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• 2021

It is difficult to establish a quantitative standard because there are many factors to consider, such as environmental conditions, airworthiness, and maintainability, in determining the installation location of equipment in an aircraft. In addition, as the number of equipment increases, the design proposal increases exponentially, so the design is proceeding depending on the experience of the designer much in order to review it within a limited time schedule. In this paper, a method of calculating the length and weight of the wiring harness according to the location of the equipment and a method of optimizing the weight of the wiring harness and the CG of the equipment using genetic algorithms are described in order to create a quantitative standard useful by comparing the optimal design and the actual design.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.7
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• pp.583-591
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• 2018

In this paper, we propose a new deployment test equipment that is characterized for the deployment test of single large solar panel with tape spring hinge. To perform the deployment test on ground, a device that takes gravity compensation into account should be used to create a zero gravity environment similar to that in orbit. We analyzed the advantages and disadvantages of the most commonly used deployment test equipment in the past through simple conceptual design, analysis, and tests to judge whether it is applicable to the deployment of the solar panel to be tested. A dummy frame was proposed to reduce the air drag effect during on-ground test and a self-aligning ball bearing and adjusting screws were applied to the deployment test equipment to solve the alignment problem with the gravity axis. And a horizontal bearing for radial movement applied to compensate for the change of the axis of the tape spring hinge. From these, we solved the problems of the conventional deployment test equipment by developing and verifying the new deployment test equipment characterized for the solar panel to be deployed in this paper.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.39-40
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• 2022

최근 전동 킥보드, 전동휠, 전기 자전거 등 개인형 이동수단(Personal Mobility)의 보급이 늘면서 관련 인명 교통사고가 급증하고 있다. 본 논문에서는 개인형 이동수단의 사용위험 및 사고 감소를 목적으로, 딥러닝 객체탐지 기술을 적용하여 다양한 위험요소를 증강현실 기술을 기반으로 한 HMD(Helmet mounted display)에 표시하는 '딥러닝 객체 인식과 증강현실을 적용한 개인 이동장치를 위한 HMD(Helmet Mounted Display) 어플리케이션'을 설계한다. 제시하는 방법은 실시간으로 수집된 전방의 실시간 영상 정보를 객체 탐지 알고리즘을 통해 위험요소 및 안전한 주행을 보조하는 객체를 감지하고 증강현실을 적용해 사용자에게 적절한 운전 보조장치 및 기능을 제공한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.8
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• pp.621-629
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• 2020

LRU layout is a complex problem that requires consideration of various criteria such as airworthiness, performance, maintainability and environmental requirements. As aircraft functions become more complex, the necessary equipment is increasing, and unmanned aerial vehicles are equipped with more equipment as a substitute for pilots. Due to the complexity of the problem, the increase in the number of equipment, and the limited development period, the placement of equipment is largely dependent on the engineer's insight and experience. For optimization, quantitative criteria are required for evaluation, but criteria such as safety, performance, and maintainability are difficult to quantitatively compare or have limitations. In this study, we consider the installation and maintenance of the equipment, simplify the deployment model to the traveling salesman problem, Optimization was performed using a genetic algorithm to minimize the weight of the connecting cable between the equipment. When the optimization results were compared with the global calculations, the same results were obtained with less time required, and the improvement was compared with the heuristic.