• Annual Conference of KIPS
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• 2009.04a
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• pp.173-176
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• 2009

본 논문에서는 감시시스템이 갖추어진 환경 내에서 발생할 수 있는 특이 행동을 효율적으로 감지하기 위한 기법을 제시한다. 최근 대형 범죄 및 방화 사건 등의 방지목적으로 DVR 의 단순 녹화를 벗어나 지능형 감시시스템을 도입하려는 연구가 활발히 진행되고 있다. 그러나 이러한 시스템들은 아직 초기 연구 단계에 있으며 영상내의 관심물체 추출을 위한 전경과 배경의 분리 및 추적 단계에 그치고 있다. 이에 본 논문에서는 가우시안 혼합 모델을 통하여 전경과 배경을 분리하고, 관심영역에 한해서 Optical Flow 기법을 이용하여 폭력상황과 같은 특이 행동의 감지 여부를 판단 할 수 있는 방법에 대해 실험을 통해 평가하였다.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.9
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• pp.915-921
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• 2013

Most of large scale solar panel handling robots adopt the timing-belt drive system for its driveline because of the simplicity and the easiness of implementation. The vibration caused by the flexure of the timing belt would increase as the size and the weight of the panel that the robot handles increase and the vibration would deteriorate the precision and/or productivity of the whole robot system. For the development of a proper control system and for the improvement of the design of the robot it is important to estimate the oscillatory response of the robot system including the flexible drive system properly. In this paper a flexible multi-body dynamics model of a large-scale solar-panel-handling robot with the flexible timing-belt drive system is developed using a generic multi-body dynamics analysis program, RecurDyn.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.6
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• pp.547-554
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• 2013

This paper proposes a novel formation algorithm of identical robots based on object tracking method using omni-directional images obtained through fisheye lenses which are mounted on the robots. Conventional formation methods of multi-robots often use stereo vision system or vision system with reflector instead of general purpose camera which has small angle of view to enlarge view angle of camera. In addition, to make up the lack of image information on the environment, robots share the information on their positions through communication. The proposed system estimates the region of robots using SURF in fisheye images that have $360^{\circ}$ of image information without merging images. The whole system controls formation of robots based on moving directions and velocities of robots which can be obtained by applying Lucas-Kanade Optical Flow Estimation for the estimated region of robots. We confirmed the reliability of the proposed formation control strategy for multi-robots through both simulation and experiment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.69-74
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• 2009

Abandoned objects should be treated as possibly dangerous things for public areas until they turn out to be safe because explosive material or chemical substance is intentionally contained in them for public terrors. For large public areas such as airports or train stations, there are limits in man-power for security staffs to check all the monitors for covering the entire area under surveillance. This is the basic motivation of developing the automatic detection system for dangerous abandoned objects based on vision technology. In this research, well-known DBE is applied to stably extract background images and the HOG algorithm is adapted to discriminate between human and stuff for object classification. To show the effectiveness of the proposed system, experiments are carried out in detecting intrusion for a forbidden area and alarming for abandoned objects in a room under surveillance.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.4
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• pp.328-336
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• 2020

This paper presents an asymptotic analysis method using the PO(physical optics) approximation technique to analyze the scattering contribution of an electrically large object partially coated with a radar absorbing material(RAM). By using the feature of the PO technique that can calculate the equivalent current value for each mesh independently, instead of analyzing the entire structure, scattering analysis was performed only by calculating the current on the area where the RAM coating is applied. By the numerical examples, the accuracy and the computation time of the proposed method were verified, and the computational efficiency of inverse synthetic aperture radar(ISAR) of the electrically large objects that require enormous resources is improved.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.687-696
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• 2019

To identify the driving dynamic characteristics of the Tractor-Trailer Type Transporter for mounting a large scale precision equipment, real vehicle driving tests on the 3 inch-bump-space-road were performed. And using general Dynamics Analysis Program - RecurDyn(V8R5), Dynamics M&S were carried out assuming the similar condition with real tests. Then the acceleration data obtained from real tests and M&S were analyzed and compared with each other in the part of root-mean-square-acceleration($g_{rms}$), peak-acceleration($g_{peak}$) and frequencies. In simple view of the $g_{rms}$ & $g_{peak}$, although the results of MRBD are more similar to ones of the real vehicle driving tests, but the results of RFlex have more information to get various useful dynamic characteristics.

• 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 Plant Biotechnology
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• v.35 no.1
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• pp.75-80
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• 2008

In vitro culture of shoot tip of garlic (Allium sativium L. cv. Seosan) was carried out to find medium condition of the induction of multiple shoots and bulbing for muliproduction of virus-free seed bulbs. For this work, tank culture was introduced. In shoot tip culture on MS solid medium the induction of multiple shoots and bulbing were better by adding 3% sucrose than 8%. Supplementation with 2mg/L 2ip and 0.2 mg/L IAA in this medium was effective. Three point three shoots including 2.7 bulbs were formed from a shoot tip after cultivation for 30 days on this medium. Bulbing of garlic in liquid culture with plastic water tank of 20L supplied air at the side of the lower part was better by adding 3% sucrose than 8% by subculture for 45 days with shoots obtained from shoot tip culture for 30 days on soid MS medium. Shoot growth was vigorous at 3% sucrose however bulb growth was more effective on the medium of 8% sucrose. Because of the effectiveness on solid medium added 3% sucrose, 2 mg/L 2ip and 0.2 mg/L IAA for initial production of multi-shoot in stem tip culture and the effectiveness in liquid culture with water tank for growth of bulbs, the method of two-step culture could be introduced for the multiple production of seed bulb of high quality. It was more desirable by supply of 0.2 mg/L BA and 0.02 mg/L NAA at tank culture time. But growth of the bulbs became poor by increasing concentration of NAA of the medium.

• Journal of Space Technology and Applications
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• v.1 no.1
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• pp.121-130
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• 2021

Since the 1960s, the United States has developed and implemented policies to encourage commercial space launches. Specifically, national policies have been implementing to expand the role of commercial space actors, which required establishing a process for private space launches. In the early days of the space age, private launches accounted for a small portion of the total launch rate, but, since the 1990s, the proportion has exploded, with private space companies presenting large projects one after another, accounting for more than 50% of the total launch rate. This diversification of space actors and the increase in orbital space objects have led to changes in the perspectives of existing space environmental management processes. During and after the Cold War, when the space age began, civilian actors' actions were limited, and policies limited their actions, too. So they had little impact on government space activities. However, space technology's entry barrier has lowered since, and policies to facilitate commercial space launches have been implemented for a long, and the accumulated amount of space waste over the past 60 years is also threatening the safety, stability, and sustainability of space use. This paper examined how the United States, the most active country in commercial space launches, has managed commercial space launches. The United States has a Space Traffic Management (STM), distributed to departments such as the Department of Defense, Department of Commerce, Department of Transport, NASA, etc. A review of changes in U.S STM management policy could also provide implications for us to manage commercial space launches in Korea.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.259-265
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• 2016

The present study aims to design and utilize a model test system of a Caisson in wet towing condition, to assess towing stability of a 9,300 ton class caisson. The suggested towing system was designed to provide regular tension on the towline, whereas the previous model test system towed the model in constant speed. The new model test system was expected to reproduce the towing condition more realistically than the test system with constant speed condition, as the tugboat in actual towing condition tows the towline with constant power. Model tests were conducted in a towing tank with 1/30 scaled model. In the model tests, six-degrees-of-freedom motion of the caisson model and tension on the towline were measured and analyzed. By using the new system, fluctuation of the motion of model and tension on the towline decreased. The variation in the draft and initial trim was applied in the model tests. In the initial trim condition, the motion and towing force decreased.