• Journal of Chest Surgery
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• v.40 no.12
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• pp.825-830
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• 2007

Background: Minimally invasive cardiac surgery appears to offer certain advantages such as earlier postoperative recovery and a greater cosmetic effect than that achieved through conventional sternotomy. However, this approach has not yet been widely adopted in Korea to replace complex open heart surgery such as mitral valve reconstruction. This study compared the results of robot assisted minimally invasive mitral valve repair with those results of conventional sternotomy. Material and Method: From December 1993 to December 2005, 520 consecutive patients underwent mitral valve reconstruction for mitral regurgitation in our institution. These patients were subdivided according to those whose surgery used the conventional sternotomy approach (Group S, n=432) and those who underwent minimally invasive right anterior thoracotomy (Group M, n=88); we then compared the clinical results of both groups. When we performed minimally invasive right thoracotomy, we used a robot (AESOP 3000) and made an incision less than 5 cm. Result: Our study patients in both groups were similar for their age, gender and preoperative ejection fraction. There were two hospital mortalities in group S. but there was no mortality in the group M patients. Significant reductions in the ICU stay and the postoperative hospital stay were observed in the group M patients compared with the group S patients. However, both the bypass time and the aortic cross-clamp time were significantly longer in the group M patients. In spite of the confined incision in the group M patients, there were no limitations on the mitral valve repair techniques. There was a similar frequency of postoperative significant residual mitral regurgitation in both groups. Conclusion: In this study, the minimally invasive mitral valve repair showed comparable early results with the conventional sternotomy patients. We will now need long-term follow-up of these patients who underwent minimally invasive mitral valve repair, but we anticipate that based on the results of this study, we will begin to routinely perform minimally invasive cardiac surgery as out primary approach for mitral valve reconstruction.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.433-435
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• 1998

인터넷이 그 규모 및 정보의 내용에서의 대형화를 지향하면서 분산환경에서 사용자들의 정보에 대한 요구가 날로 증가하고 있고, 이를 만족시킬 수 있는 저 단계로 정보 수집이라는 것이 새로운 문제로 떠오르고 있다. 이에 에이전트를 기반으로 구성된 분산 디지털 도서관상에서 웨 정보 서비스를 제공하기 위한 로봇 에이전트를 설계.구현하였다. 구현된 로봇은 JAVA와 RMI를 기반으로 에이전트화를 통해 분산환경 구조를 갖추고 있으며, 멀티 쓰레드와 로봇 제어 알고리즘을 통해 정보의 수집 및 관리에 있어서 로봇의 신뢰도를 향상 시켰고 DBMS와 에이전트의 연계를 통한 대용량 처리 기능과 관리자의 관리의 편리성을 도모하기 위해 자동화 기능을 갖추었으며, 로봇과 관련되어 발생할 수 있는 부하를 최소화 할 수 있도록 하였다.

• Journal of Mechanical Science and Technology
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• v.14 no.11
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• pp.1225-1231
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• 2000

This paper proposes a V-shaped Lyapunov function approach for the model-based control of flexible-joint robots, in which a new model-based nonlinear control scheme is designed based on a V-shaped Lyapunov function. The proposed control guarantees global asymptotic stability for link trajectory control while keeping all internal signals bounded. Since joint flexibility is used as a control parameter, the proposed control is not restricted by the degree of joint flexibility and be applied to flexibility-joint, partly-flexibility, or rigid-joint robots without modification. the effectiveness of the proposed control has been by computer simulation.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.339-348
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• 2010

One of the requirements for autonomous vehicles on off-road is to move stably in unstructured environments. Such capacity of autonomous vehicles is one of the most important abilities in consideration of mobility. So, many researchers use contact and/or non-contact methods to determine a terrain whether the vehicle can move on or not. In this paper we introduce an algorithm to classify terrains using visual information(one of the non-contacting methods). As a pre-processing, a contrast enhancement technique is introduced to improve classification of terrain. Also, for conducting classification algorithm, training images are grouped according to materials of the surface, and then Bayesian classification are applied to new images to determine membership to each group. In addition to the classification, we can build Traversability map specified by friction coefficients on which autonomous vehicles can decide to go or not. Experiments are made with Load-Cell to determine real friction coefficients of various terrains.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.45-48
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• 2006

The system that can generate biological brain information processing mechanism more precisely may have several abilities such as exact cognition, situation decision, learning and inference, and output decision. In this paper, to implement high level information processing and thinking ability in a complex system, the information processing layer based on the biological brain is introduced. The biological brain information processing mechanism, which is analyzed in this paper, provides fundamental information about intelligent engineering system, and the design of the layer that can mimic the functions of a brain through engineering definitions can efficiently introduce an intelligent information processing method having a consistent flow in various engineering systems. The applications proposed in this paper are expected to take several roles as a unified model that generates information process in various areas, such as engineering and medical field, with a dream of implementing humanoid artificial intelligent system.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.1
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• pp.45-52
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• 2015

In this paper, the repeated learning technique of neural network was used for gripping force control algorithm. The hybrid control system was introduced and the manipulator's finger reorganized form 2 ea to 3 ea for comfortable gripping. The data was obtained using the gripping force of repeated learning techniques. In the fucture, the adjustable gripping force will be obtained and improved the accuracy using the artificial intelligence techniques.

• Journal of the KSME
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• v.22 no.4
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• pp.271-280
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• 1982

최근 제조업과 공작기계 기술에 있어 세계를 지배하는 추세는 CIM (computer integrated manufacturing)의 도입이다. 그 이유는 CIM을 도입하여 발전시키고 개발시키는 국가에 대해서 장기적인 경제적, 사회적 이익을 주기 때문인 것이다. 이러한 추세는 제조업과 공작기계 분야에 컴퓨터와 관련된 기술의 개발과 응용에 있어 다음의 5가지 영역으로 구분된다. 즉, 일체화된 제조 소프트웨어 시스템 (integrated manufacturing software system), 그룹 기술 (group technology), 구획식제온 (cellular manufacturing), 공작기계의 컴퓨터제어 및 시험, 그리고 컴퓨터 제어식 산업 로봇(robot) 및 가변 제조(flexible manufacturing)이다. 미국에서 이러한 각 분야에 행해지고 있는 예로 응용되고 있으며, CIM이 가져다 주는 경제적, 사회적 이익을 추구 하는 국가들에 의해 많이 연구되고 있다. 이러한 노력은 이십세기말 이전에 이들 국가의 제조 업에 대단한 변화를 가져올 것이다.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2189-2192
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• 1998

The objective of this paper is, based upon the principles of artificial life, to induce emergent behaviors of multiple autonomous mobile robots which form from simple local rules to complex global intelligence. Here, we propose an architecture of neural network learing with reinforcement signals which perceives the neighborhood information and decides the direction and the velocity of movement as mobile robots navigates in a group. As results of the simulations, the optimum weights are obtained in real time, which not only prevent from the collisions between agents and obstacles in the dynamic environment, but also have the mobile robots move and keep in various patterns.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3030-3032
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• 1999

This Paper proposes a fuzzy algorithm for cooperative behaviors of multiple autonomous mobile robots. Each robot makes decision of his behavior based on the information obtained by infrared sensors to measure the position and velocities of other robots. The effectiveness of the proposed algorithm is shown by some computer simulation where a group of mobile robots encircles with equi-interval.

• The Journal of Korea Robotics Society
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• v.13 no.4
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• pp.220-229
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• 2018

In the midst of disaster, such as an earthquake or a nuclear radiation exposure area, there are huge risks to send human crews. Many robotic researchers have studied to send UGVs in order to replace human crews at dangerous environments. So far, two-dimensional camera information has been widely used for teleoperation of UGVs. Recently, three-dimensional information based teleoperations are attempted to compensate the limitations of camera information based teleoperation. In this paper, the 3D map information of indoor and outdoor environments reconstructed in real-time is utilized in the UGV teleoperation. Further, we apply the LTE communication technology to endure the stability of the teleoperation even under the deteriorate environment. The proposed teleoperation system is performed at explosive disposal missions and their feasibilities could be verified through completion of that missions using the UGV with the Explosive Ordnance Disposal (EOD) team of Busan Port Security Corporation.