• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.9
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• pp.639-646
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• 2022

Landing site searching algorithms are developed for a quadrotor using a depth map in unknown environment. Guidance and control system of Unmanned Aerial Vehicle (UAV) consists of a trajectory planner, a position and an attitude controller. Landing site is selected based on the information of the depth map which is acquired by a stereo vision sensor attached on the gimbal system pointing downwards. Flatness information is obtained by the maximum depth difference of a predefined depth map region, and the distance from the UAV is also considered. This study proposes three landing methods and compares their performance using various indices such as UAV travel distance, map accuracy, obstacle response time etc.

• The Journal of Korea Robotics Society
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• v.18 no.3
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• pp.241-250
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• 2023

This paper describes the posture stabilization control of a bipedal transformer robot being developed for military use. An inverted pendulum model with a rectangular that considers the robot's inertia is proposed, and a posture stabilization moment that can maintain the body tilt angle is derived by applying disturbance observer and state feedback control. In addition, vertical force and posture stabilization moments that can maintain the body height and balance are derived through QP optimization to obtain the necessary torques and vertical force for each foot. The roll and pitch angles of the IMU sensor attached to the robot's feet are reflected in the ankle joint to enable flexible adaptation to changes in ground inclination. Finally, the effectiveness of the proposed algorithm in posture stabilization is verified by comparing and analyzing the difference in body tilt angle due to disturbances and ground inclination changes with and without algorithm application, using Gazebo dynamic simulation and a down-scale test platform.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.194-203
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• 2011

This study investigated the effectiveness of visual biofeedback simulation training for patients with incomplete spinal cord injuries. Fifteen people with an ASIA impairment scale of C and D, according to the intervention method, were studied. They were randomly divided into two groups, seven people in the experimental group and eight people in the control group. They were studied three times a week for six weeks using a Tetrax Interactive Balance System, for a total of eighteen times, and each test took fifteen minutes. Paired t-tests were used to evaluate the changes before and after intervention. The difference between the groups was compared using an independent t-test. The experimental group showed significantly increased general stability, fall risk index, weight distribution (A, C, D, LEFT, HEEL) and weight distribution index, except for synchronization AC, BD. However, the control group only showed significantly increased weight distribution (A, C, LEFT). In a variation, experimental and control groups showed significantly increased weight distribution (A, B, C, HEEL), general stability, fall risk index and synchronization AD. Consequently, it was found that visual biofeedback simulation training was effective for the balance ability of incomplete spinal cord injury patients, and further studies are required.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.277-285
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• 2020

The purpose of this study was to evaluate the effects of wearing Head-Mounted Display (HMD) on the cervical range of motion (CROM), neck muscle thickness, and pain in healthy young adults. The HMD group(male=16, female=7) was asked to perform sitting comfortably in a backless chair with hands on their knees with the HMD was worn on their heads to watch the video for 30 minutes. The control group(male=15, female=8) was asked to sit in the same posture as the HMD group for 30 minutes. CROM, neck muscle thickness, and pressure pain threshold (PPT) of both the upper trapezius and levator scapulae were measured before and after intervention. CROM and PPT of the upper trapezius and levator scapulae in the HMD group were significantly decreased and the thickness of the muscles in the HMD group were significantly increased more than in the pre-test (p<.05). There was no significant difference in CROM, muscle thickness, and PPT in the control group. Wearing HMD for a long time can cause a decrease in CROM and PPT and an increase in muscle thickness, and there is a risk of developing musculoskeletal disorders in the neck and shoulder. Therefore, this study recommends maintaining the correct posture of the neck and shoulder and using HMD only for an appropriate time.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.575-580
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• 2013

The IMU(Inertial Measurement Unit) which is the expensive equipment has been used as a special limited area, usually in measurement of posture of applying to the areas of ship, submarine, aircraft and military equipment application. However, in the current situation, MEMS AHRS technology can replace the high-priced IMU in MEMS AHRS selected application field. In this paper, wireless hull motion measurement system was suggested for measuring key elements of ship's movement such as rolling, pitching and yawing using gyro, acceleration and magnetic sensors of AHRS. In order to reduce the error such as instantaneous acceleration, effects and vibration of geomagnetic, we have adopted the sensors equipped with Kalman filtering. The Wireless hull motion measurement system using AHRS sensors was tested in actual ship and it could easily be applied in limited installation circumstances of the ship. In the future, this system can be useful in the navigation safety and marine accident analysis by using with ship equipment such as INS or VDR in the maritime.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.1 s.24
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• pp.21-28
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• 2007

It is very difficult to forecast accurately a damage from the natural disaster which occurs frequently due to the climate change. When the significant weather event is forecast, it will be able to minimize a damage with the suitable prevention action. But 2000's our country meterological disaster damage is a several trillion won. Therefore, this paper analyzes Korea Meterological Administration, Japan Meterological Agency, television and newspaper have reported, information substance, transmission system, an ex post facto valuation about typhoon Nabi between september $5{\sim}7$ in 2005 and heavy rainfall in 1998 at Japan. Through the investigation, we want to present basic data order to rises the application effect of disaster prevention meterological information. We think KMA must present many information report to promote a people's understanding about the meterological information and the serious disaster situation. Also the disaster damage estimation model development is necessary, which forecasts the accurate damage scale due to the weather event, such as typhoon, heavy rainfall, strong wind. And also we think the KMA, National Emergency Management Agency, related agency, television and newspaper must positive reports the contents which is suitable to disaster response phases and an ex post facto examination. Then it grasps the problem of disaster prevention meterological information and must improve effectively.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.365-372
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• 2017

Squat exercise is one of the important free weight exercises that can safely and effectively expect the athletic performance by establishing the rationale. Therefore, it is necessary to study the side effects caused by incorrect exercise, scientific countermeasures and to develop a exercise estimation model. It is effective and accurate to use a variety of assistive devices to calibrate athletic posture. The issues of the structural analysis for designing a foot plate for squat exercise is to model the behavior by the dynamic behavior. It should be consider that the center of gravity of each segmented body is different when the maximum load is applied. It is applied to complete system design through simulation method with kinematic dynamic, ground reaction force and load analysis for the free weight exercise equipment, VR device, and safety foot plate. In this paper, the authors propose the design method for the vertical load distribution applied in the design of the foot plate used for the squat exercise mechanism, and based on these results, design make the more safe and reliable free weight exercise equipment system.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.372-376
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• 2006

현재 심각한 재해에 대한 임박성은 일부 관계자 이외는 감지하지 못하고 있는 것이 현실이다. 재해와 같은 위기에 관한 지식이나 이에 대처하기 위한 기술은 어린 시절부터 습득해 두어야 할 기초적 지식 및 능력이라고 생각한다. 그럼에도 불구하고 대지진 발생이 임박하고 있음을 타인의 일처럼 생각하고 있다는 점은 재해와 같은 위기를 자신의 일처럼 생각하고 어떻게 대처해야 할 것인가에 대해 스스로 생각할 수 있는 기회가 충분하지 않다는 것에서 유래한다. 즉 체계적 실천적인 방재 위기관리교육이 충분하게 실시되지 않고 있다는 점을 지적할 수 있을 것이다. 특히 지역주민의 생명 신체 재산을 보호해야 하는 지방자치단체의 소방담당직원의 실천적 대응능력은 말할 것도 없고 수장(首長)의 리스크 관리능력에 대해 의구심을 가지고 있다. 또한 지역 자체의 방재력 강화라는 관점에서는 자주방재조직 등의 지역방재리더나 지역주민 개개인의 방재능력을 향상시켜야 할 필요성이 강조되고 있다. 최근에 건설된 신관저를 계기로 변화된 방재 위기관리 시스템에 관한 정책적 동향을 살펴본다. 아울러 방재 위기관리에 대한 인재양성을 위한 교육의 일환으로 구축된 e-Learning System인 e-College의 구성 및 관련 내용을 살펴봄으로써 정책적 시사점을 도출하고자 한다. 지방자치단체의 방재 위기관리에 있어서 수장 등 간부직원의 의식과 자세가 지역의 방재력을 크게 좌우하는 것으로 볼 수 있다. 방재담당직원 소방직단원에 대한 교육과제를 들 수 있겠다. 고도로 도시화된 사회가 재해에 대한 취약성이 높아지고 있다. 지역의 방재리더, 재해자원봉사, 주민에 대한 교육과제로 도도부현, 시정촌, 대학에서 방재 위기관리 교육이 실시되고 있지만, 1999년 총리부(總理府)에서 여론조사를 보면 자주방재활동에 참가한 경험이 없는 사람이 전체 70%를 차지하고 있다. 기업에 대한 교육과제로 재해발생시에 사원이나 고객의 안전 확보, 사업의 피해경감 조기복구에 의한 경제에 대한 영향을 경감하기 위한 준비를 충실히 해야 한다.

• Journal of Korean Library and Information Science Society
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• v.35 no.4
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• pp.361-375
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• 2004

This study was to predict through the scenarios, one of the forecast technique the future of library service. In order to do that literature reviews, analysis of library's home page and specialist interview were conducted. As a result, it appeared that based on the scenarios to predict the middle future(after 5-10 years) of library service. The results of this study are as follows. The first the future information environment is represented by mobile md ubiquitous. Through this, anytime, anywhere, any device, we can be taken any media The second, the unreliable factors come out in time lag, the supply speed of terminals, library services, copyrights and so on. The third, as the supply speed of technique and the speed of technological development, the speed of technological development and the solution speed of digital copyright problem these make various scenarios. The fourth library try to find unreliable factors in constant change of the information technique, variety of internal factors. And strategy needs to dispose of various scenarios properly.

• Journal of the Korean Society for Library and Information Science
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• v.38 no.4
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• pp.105-123
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• 2004

This study was to predict through the trend analysis, one of the forecast technique, the future of library End Information center. In order to do that literature reviews, analysis of library's home page and specialist interview were conducted. As a result, It appeared that based on the trend analysis to predict the middle future(after 5-10 years) of library and information center. The results of this study are as follows. The first, the future information environment is represented by mobile and ubiquitous. Through this, anytime, anywhere, any device, we can be taken any media. The second, the problems of future library are technical, economic, social, ethical and legal problem. The third, unreliable factors come out in time lag, the supply speed of terminals, library services, copyrights and so on. The fourth, the future library is expanded through wireless terminal information access and use, development of mobile technique, universal ubiquitous environment and electronic information's use are extended.