• Journal of the Institute of Convergence Signal Processing
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• v.7 no.1
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• pp.38-44
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• 2006

The omnidirectional mobility of a mobile robot may lose significance in motion control, unless the isotropy characteristics of the mechanism is maintained well. This paper investigates the local and global isotropy of an omnidirectional mobile robot with three caster wheels. All possible actuations with different number and combination of rotating and steering joints are considered. First, the kinematic model based on velocity decomposition and the algebraic conditions for the local isotropy are obtained. Second, the geometric conditions for the local isotropy are derived and all isotropic configurations are fully identified. Third, the global isotropy index is examined to determine the optimal parameters in terms of actuation set, characteristic length, and steering link length.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.208-210
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• 2001

차세대 이동통신 시스템에서 이동단말에 대한 착호를 설정하기 위해서는 위치관리가 필요하다. 기존의 동적 위치관리 기법에서는 시간, 거리, 이동회수와 같은 단편적인 이동 특성을 위치갱신의 기준으로 채택하였다. 이런 기법들은 다양한 이동성을 갖는 이동단말에 대해서 그 위치관리 비용의 편자가 크다. 가장 효율적인 것으로 알려져 있는 거리기반 기법은 이동거리만을 위치관리의 기준으로 택함으로서 이동이 적은 이동단말에 대해서는 갱신비율이 현저히 낮아짐으로서 그 비용이 작지만, 반대로 이동성이 많은 경우에는 갱신비용이 커진다. 따라서 본 논문에서는 위의 거리기반 기법의 이런 단점을 개선하면서 이동단말의 이동성을 이동거리와 시간에 의해 결정되는 속도로 나타내고, 그 속도에 따라 거리 임계값 및 시간 임계값을 조정하여 위치갱신 및 페이징을 수행하는 새로운 위치관리 기법을 제안한다. 세안된 기법의 효율성을 제시하기 위하여 분석적 모델 및 수치적 결과를 통하여 제안하는 기법과 기존의 거리기반 기법의 총 비용을 구하였으며, 그 결과 제안된 기법은 가변적인 속도 변화를 보여주는 이동단말의 이동성에 대하여 효율적임을 보여 준다.

• Journal of Digital Contents Society
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• v.6 no.3
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• pp.157-162
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• 2005

In this paper we propose real-time cocersion methods that can convert into stereoscopic image using depth map that is formed by motion detection extracted from 2-D moving image and region segmentation separated from image. Depth map which represents depth information of image and the proposed absolute parallax image are used as the measure of qualitative evaluation. We have compared depth information, parallax processing, and segmentation between objects with different depth for proposed and conventional method. As a result, we have confirmed the proposed method can offer realistic stereoscopic effect regardless of direction and velocity of moving object for a moving image.

• Annual Conference of KIPS
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• 2017.11a
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• pp.888-890
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• 2017

VR browser is one of the most popular applications for VR(Virtual Reality) environment. However, because most of the web contents are not designed considering the VR environment, scrolling the web pages in the VR browser causes much visual discomfort. We found it's because the angular velocity of the eye movement during scrolling increased because the viewing distance got closer compared with legacy devices. So we have developed a technology that regulates the scrolling to reduce the visual discomfort in the VR browser, in reference of the visual perception characteristics of the human visual system.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.3
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• pp.231-238
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• 2017

In this paper, we propose a method of analyzing exercise behavior to increase health care and exercise effect in personal fitness. In this study, a user wears a band-shaped acceleration sensor, an angular velocity sensor, and a motion sensor equipped with a geomagnetic module. Using the technique presented in this paper, we analyzed the motion of three resistive exercises which is consistent with previous studies. We have acquired a technique for processing personalized exercise information from the data generated in the resistive exercise situation.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1658-1661
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• 2002

In this paper, we propose the intelligent inference trace algorithm of the mobile robot using fuzzy logic. With the proposed algorithm, the mobile robot can trace human at regular intervals. The mobile robot can recognize the distances between it and human with both multi-ultrasonic sensors and PC-camera and then, can inference the direction and velocity of itself to keep the given regular distances. In the first, the mobile robot acquires the information about circumstances using ultrasonic sensor and PC-camera then secondly, recognize the status of circumstances using the fuzzy logic. We also evaluate the experimental navigation test at several times to verify the ability of the fuzzy logic controller.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.1007-1008
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• 2006

This paper presents a optimal path search of mobile robot using energy efficiency. Proposed method has two goals that determining the velocity of mobile robot and finding the optimal path. We model the relationship of motors' speed and power consumption with quadratic polynomials. In order to verify the effectiveness of the proposed method, we performed simulations on the energy consumption of different paths.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.510-512
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• 2013

본 논문에서는 이동 에드 혹 네트워크(Mobile Ad-hoc network: MANET)에서의 상황인식 기반의 에너지 스케쥴링 기법인 ESWC(Energy Scheduling Weighted-value Control) 알고리즘을 제안한다. 기존 MANET에서 노드의 에너지를 관리하기 위한 여러 가지의 방법들이 제안 되고 있다. 특히 이동노드들의 경우 이동성에 따라 에너지 소모율이 다르며, 이때 상호 노드간 전송하는 데이터와 상호 위치에 따라 에너지 소모율은 다르게 된다. 본 논문에서는 계층적 클러스터 단위의 동적인 토폴로지에서 전송 거리와 전송 데이터의 패킷량이 어떠한 상호관계에 따라 노드의 소모 에너지에 미치는 영향이 있는지를 분석한다. ESWC에서 도출된 에너지의 가중치 결과는 최종적으로 전송 경로에 있어 에너지 소모율을 분석하여 네트워크상에서 전체적인 노드의 라이프타임을 향상 시킬 수 있다. 본 연구의 주어진 모의실험환경에서 노드의 방향성 및 시간에 따른 이동성을 반영함으로써 에너지 효율적인 클러스터링 및 라우팅 경로 알고리즘이 제공되어 네트워크의 최적화된 에너지 소모 결과를 보여주었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.1968-1974
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• 1997

In this paper, the spectral domain approach is employed to investigate the characteristics of symmetrical and asymmetrical broadside-coupleed coplanar waveguides(BSC-CPW). These structures have large even(c)-odd(.pi.) mode-velocity ratio, suitable for wide-band and tight-coupling microwave circuit design. Efficient design parameters can be obtained from the effective dielectric constants and characteristic impedances calculated by varying the strip widths and slot widths in the BSC-CPW structure.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.11
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• pp.1095-1101
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• 2006

The clean tube system was developed as a means of transferring air-floated wafers inside a closed tube filled with super clean air. This paper presents a wafer position sensing method in the clean tube system, where the photo proximity sensors are used. The first presented method uses the two positions sensed lately in order to compute the wafer center position. The next method uses the latest sensed position and the next latest position compensated with the information of the wafer velocity. The third method uses the kalman filter, which enable us to use all the previous sensing information. The simulation results are compared to show results of the presented method. In addition, the paper presents a control method to stop the wafer at the center of the unit in the clean tube system. The experimental clean tube system worked successfully with the applying the both presented methods of sensing and control.