• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.233-235
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• 2012

해저보행로봇 CR200은 여러 개의 관절로 이루어진 6개의 다리를 이용하여 해저면에서 보행으로 이동하며 해저 정밀탐사 및 작업을 수행하는 로봇으로, 케이블로 연결된 선상제어실에서 원격 제어된다. CR200 시스템에서는 16개의 카메라가 장착될 예정이며, 취득된 카메라의 영상은 선상제어실의 비디오 컴퓨터로 전송되어 모니터링 및 녹화된다. 설계된 비디오 시스템에서 영상 전송은 전자기 간섭에 의한 화질 열화를 최소화하기 위하여 기가비트의 대역폭을 가진 이더넷과 광케이블을 통하여 디지털 형태로 전송되며, 아날로그 카메라의 영상은 비디오 인코더를 사용하여 디지털 영상으로 변환된 후에 전송된다. 본 논문에서는 CR200의 비디오 시스템의 설계를 소개하고, 실제로 제작하기 전에 설계된 비디오 시스템을 검증하기 위하여 테스트베드를 사용한 통합 테스트 결과를 제시한다. 아직 준비되지 않은 카메라에 대해서는 아이패드의 아날로그 영상 출력을 비디오 인코더의 입력으로 전달하여, 설계된 모든 카메라들이 동작하는 상황을 테스트베드로 실험하였다. 16개 카메라의 영상이 모니터링 및 녹화되는 상황을 테스트베드로 실험한 결과에 따르면, 압축률 10%의 H.264 동영상 압축 알고리즘을 사용할 경우에 30fps 영상의 모니터링 및 녹화에 각각 60Mbps의 전송량으로 비디오 시스템이 정상적으로 동작하는 것을 확인할 수 있었다. 비디오 데이터의 전송은 센서 및 제어 데이터의 전송과 같은 네트워크를 사용하지만, 비디오 데이터의 기가비트 네트워크 사용률은 평균 12%이기 때문에 비디오 데이터 전송으로 인하여 데이터 통신은 거의 영향을 받지 않는다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.659-665
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• 2010

This paper proposes a control algorithm for quadruped robots moving on irregularly sloped uneven surfaces. Since the body balance of a quadruped robot is controlled by the forces acting on its feet during touchdown, the ground reaction force (GRF) is controlled for stable running. The desired GRF for each foot is generated on the basis of the desired galloping pattern; this GRF is then compared with the actual contact force. The difference between the two forces is used to modify the foot trajectory. The desired force is realized by considering a combination of the rate change of the angular and linear momenta at flight. Then, the amplitude of the GRF to be applied at each foot in order to achieve the desired linear and angular momenta is determined by fuzzy logic. Dynamic simulations of galloping motion were performed using RecurDyn; these simulations show that the proposed control method can be used to achieve stable galloping for a quadruped robot on irregularly sloped uneven surfaces.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.27-36
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• 2018

In this paper, we design and implement a real time IoT messaging system that can collect location information of moving vehicles and pedestrians in real time using MQTT protocol and provides location based information service in administrative area. We implemented MQTT based IoT device for vehicle location information collection and communication and MQTT based smartphone application for pedestrian location information service. IoT clients can send messages to the server in administrative units by using the MQTT Topic which is equal to administrative names. The SLIMS (Seoul Location based IoT Messaging System) implemented in this study is able to analyze the real time traffic volume of pedestrians and vehicles by tracking clients. It also can deliver messages to clients based on coordinate range. SLIMS can be used as a real-time location-based information service for large-scale IoT devices such as real-time flow population and vehicle traffic analysis and location-based message delivery.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.494-499
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• 2011

This paper presents the biomechanical analysis and evaluation technology of musculoskeletal system by multi-body human dynamic model and 3-D motion capture data. First, medical image based geometric model and material properties of tissue were used to develop the human dynamic model and 3-D motion capture data based motion analysis techniques were develop to quantify the in-vivo joint kinematics, joint moment, joint force, and muscle force. Walking and push-up motion was investigated using the developed model. The present model and technologies would be useful to apply the biomechanical analysis and evaluation of human activities.

• Journal of the HCI Society of Korea
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• v.14 no.2
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• pp.41-47
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• 2019

In this study, a smart assistive device is designed to recognize pedestrian signal and to provide audio instructions for visually impaired people in crossing streets safely. Walking alone is one of the biggest challenges to the visually impaired and it deteriorates their life quality. The proposed device has a camera attached on a pair of glasses which can detect traffic lights, recognize pedestrian signals in real-time using a machine learning algorithm on GPU board and provide audio instructions to the user. For the portability, the dimension of the device is designed to be compact and light but with sufficient battery life. The embedded processor of device is wired to the small camera which is attached on a pair of glasses. Also, on inner part of the leg of the glasses, a bone-conduction speaker is installed which can give audio instructions without blocking external sounds for safety reason. The performance of the proposed device was validated with experiments and it showed 87.0% recall and 100% precision for detecting pedestrian green light, and 94.4% recall and 97.1% precision for detecting pedestrian red light.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.585-592
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• 2014

In this study, a multibody simulator was developed to analyze the bio-mimetic motion of a lizard robot design. A RecurDyn multibody dynamics model of a lizard was created using a micro-computerized tomography scan and motion capture data. The bio-mimetic motion simulator consisted of a trajectory generator, an inverse kinematics module, and an inverse dynamics module, which were used for various walking motion analyses of the developed lizard model. The trajectory generation module produces spinal movements and gait trajectories based on the lizard's speed. Using the joint angle history from an inverse kinematic analysis, an inverse dynamic analysis can be carried out, and the required joint torques can be obtained for the lizard robot design. In order to investigate the effectiveness of the developed simulator, the required joint torques of the model were calculated using the simulator.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.3
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• pp.94-104
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• 2016

In this study, factor and cluster analysis are used to classify characteristics of the administrative basic unit, "Dong", of the Incheon Metropolitan City. Travel characteristics of the classified groups are then analyzed through databases to provide directions of urban transportation planning. First, industrially developed administrative-dong show a high commuting volume by using cars. Thus the analysis indicated the need to staggering work-hour system and signal operating system policy. Second, commercially developed administrative-dong show heavy use of public transportation and long distance commute as well as high volume of shoppers. The analysis indicated the need to improve road infrastructure. Third, densely populated administrative-dong show a high rate of commute to work and school as well as long hours of commuting. Thus the analysis indicated the need to improve road transportation policies during rush hours. Fourth, administrative-dong with multiple characteristics feature heavy pedestrian traffic thus the study analyzed the need to improve pedestrian environment policies. Lastly, administrative-dong in close proximity to train stations feature extensive use of biking as well as high volume of shoppers and students commuting. Thus the study analyzed the necessity to have plans to enhance accessibility.

• Journal of the Korea Convergence Society
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• v.10 no.3
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• pp.39-47
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• 2019

In this paper, we proposed extracting modified Histogram of Oriented Gradients (HOG) features using background removal when tracking pedestrians in real time. HOG feature extraction has a problem of slow processing speed due to large computation amount. Background removal has been studied to improve computation reductions and tracking rate. Area removal was carried out using S and V channels in HSV color space to reduce feature extraction in unnecessary areas. The average S and V channels of the video were removed and the input video was totally dark, so that the object tracking may fail. Histogram equalization was performed to prevent this case. HOG features extracted from the removed region are reduced, and processing speed and tracking rates were improved by extracting clear HOG features. In this experiment, we experimented with videos with a large number of pedestrians or one pedestrian, complicated videos with backgrounds, and videos with severe tremors. Compared with the existing HOG-SVM method, the proposed method improved the processing speed by 41.84% and the error rate was reduced by 52.29%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.4
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• pp.768-778
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• 1998

Human beings usually absorb a shock from terrain during walking through the damping effects of joints, muscles and skin. With this analogy, a robot-leg with a shock absorber is built to absorb the impact forces at its foot during high-speed walking on irregular terrain. To control the hip position while walking, the dynamic controller suitable for high speed walking is designed and implemented based on a dynamic model by Kane's equation. The hip position tracking performances of various controllers (PID controller, computed torque controller and feedforward torque controller) are compared through the experiments of the real robot-leg.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1346-1349
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• 2007

신축 구조물의 설계 단계에서 동적 강도 기준 및 진동 설계 기준을 설정하고 사람의 거동에 따른 기준층 구조의 동적 사용성 및 건물의 용도별 진동 영향성 평가를 동적 시뮬레이션 기법을 토대로 정량적인 방법을 통하여 수행하고 그 결과를 바탕으로 건물 사용성 및 용도에 따른 구조물의 안정성, 근무 요원들의 근무 환경 및 건물 운용의 관점에서 진동 영향성 평가를 수행함과 동시에 필요한 경우 최적의 동적 대책을 수립한다. 또한 건물 내부의 운용설비가 구조물에 미치는 영향을 평가하여 최적의 방진 대책을 제시하여 건물 완료 후 발생할 수 있는 진동 문제를 최소화 하고자 한다.