• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.11a
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• pp.105-108
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• 1997

We developed a FLC(Fuzzy Logic Controller) for tracking control of MR(Mobile Robot) with obstacle avoidance. In this research, we made a heuristic approach to tracking control which is simple and efficient in almost every situation using FLC. In addition, smooth turn is accomplished and also obstacles are avoided. Also we used the XX(don't care) linguistic variable for inputs in FLC to make simple rule-table. With various simulations, the validity of our FLC was shown.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.5
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• pp.44-51
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• 2008

In this paper, the optimal tuning of a cross-coupled controller linked with the feedforward controller is studied to reduce contouring and tracking errors of a bi-axial servomechanisms by using the previously developed integrated tuning method. The CCC system for an arbitrary curve, which is combined with the feedforward controller, is formulated by a state-space based on a series of linear motion trajectories. An optimal tuning problem is formulated as a nonlinear constrained optimization problem including relevant controller parameters of the servo. To verify the effectiveness of the proposed optimal tuning procedure, linear and circular motion experiments are performed on the xy-table. Experimental results confirm that both tracking and contouring errors are significantly reduced by applying the proposed control and tuning system.

• Journal of Korean Elementary Science Education
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• v.31 no.3
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• pp.358-371
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• 2012

The main purpose of this study was to examine elementary teachers' visual attention that appears in science textbook tables. This paper proposed that teachers' cognitive effectiveness can be different by the presence or absence of the title of tables. The eye fixation data of participants are collected by the eye tracker apparatus. Participants in this study were 10 elementary school teachers and the table on the 2007 revised science textbooks were selected as experimental stimuli. Information about eye-fixations are recorded when subjects are given 4 tables by eye tracker. Eye-fixation time as well as the ratio and the number of fixation can be obtained by using the eye tracker but also we can acquire a significant conclusion through these outcomes. As the result of the experiment, it took less time to interpret in the presence of the title than in the absence of it. However, this result is only effective only for the interpretation of simple stimulus; the presence of title does not influence on fixation time in the analysis of complicated stimulation. This study showed that it is better to insult the title in the tables because it helps teachers to recognize contents of the tables effectively.

• The KIPS Transactions:PartD
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• v.13D no.1 s.104
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• pp.103-110
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• 2006

The Game development process that the Korea Game Development Infinity researches and publishes has laid important groundwork for the game industry. However, the game design cannot guarantee a software quality because an artifact is made incorrect by a game planner's new idea and modification. In this paper theorized the system to maintain artifacts consistently that is generated in planning phase and make changed contents traceable. First, it defined an ACT graph to represent relation of between artifacts, a ACT table that traces and manages it changes and a table of artifacts change history. Also, it suggested the ACT process applying as we mentioned above. Then we worked a case study to verify the change tracking technique which is presented. In a case study, we find game designer is capable to grip and modify a change of artifacts when it occurs a change of game design artifacts. As a result of that, we can save the time and effort to maintain the consistency among game design artifacts.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.296-301
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• 2005

This paper describes the kinematics, dynamics and control of a 6-DOF shaking table with a bell crank structure, which converts the direction of reciprocating movements. In this shaking table, the bell crank mechanism is used to reduce the amount of space needed to install the shaking table and create horizontal displacement of the platform. In kinematics, joint design is performed using $Gr{\ddot{u}}bler's$ formula. The inverse kinematics of the shaking table is discussed. The derivation of the Jacobian matrix is presented to evaluate singularity conditions. Considering the maximum stroke of the hydraulic actuator, collision between links and singularity, workspace is computed. In dynamics, computations are based on the Newton-Euler formulation. To derive parallel algorithms, each of the contact forces is decomposed into one acting in the direction of the leg and the other acting in the plane orthogonal to the direction of the leg. Applying the Newton-Euler approach, the solution of inverse dynamics is almost completely parallel. Only one of the steps-the application of the Newton-Euler equations to the platform-must be performed on one single processor. Finally, the efficient control scheme is proposed for the tracking control of the motion platform.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.828-831
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• 1997

One of the most important design factor for the image tracker is the speed of the data processing which allows real-time operation of the system and provides reasonably accurate performance at the same time. Use of powerful DSP alone does not guarantee to meet such requirement. In this paper, a simple efficient algorithm for real-time multi-target image tracking is suggested. The suggested method is based on a recursive centroiding technique and color table look-up. This method has been successfully implemented in a image processing system for Micro-Robot Soccer Tournament(MIROSOT). This tracker can track positions of a ball, 3 enemies, and 3 agents at the same time. The experimental results show that the processing time for each frame of image is less than 7ms, which is well within the 60Hz sampling interval for real-time operation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.64-69
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• 2004

The work presented here deals with controller design using error model constructed with proportional control ramp response. The design aims at the improvement of transient response, steady-state error reduction with stability preservation, generation of the consistent contour error through the proportional gain regulation of a mismatched system. The first step is to generate tracking-error curve with proportional control only and decide the added error signal shape on the error curve. The next is to construct a table for the steady-state loop gain with step input. The table is used for selecting the proportional gain. The effectiveness of the proposed controller is confirmed through the simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.11
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• pp.487-494
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• 1986

This paper is concerned with the techniques of error check and reduction of state diagram using logic programming. Error check program aims to check not only syntax errors but also semantic errors. And reduction program optimizes the state diagram by finding the redundant equivalence states and removing those from the set of states. The input of both program is state diagram represented as state table form. The output of error check program is error comment. The output of reduction program is equivalence reduced state table. Both programs are implemented using prolog. Prolog has very powerful pattern matching, and its automatic back-tracking capabilities facilitate easy-to-write error check and reduction programs.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.208-217
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• 1998

본 연구에서는 ER 브레이크와 ER클러치를 피드백작동기로 사용하여 이송테이블의 위치 추적제어를 수행하였다. 이를 위해 먼저 아라빅 검(arabic gum)계통의 ER유체를 자체조성한 후 전기장에 대한 빙햄(Bingham)모델을 실험적으로 도출하였다. 빙햄모델에 근거하여 평판형의 ER브레이크와 실린더형의 ER클러치를 설계 제작하였으며, 계단입력(step input)전기장에 따른 출력토오크특성을 통하여 이들 작동기의 동적모델을 얻었다. 이들 작동기와 연계된 이송테이블시스템의 운동지배방정식을 유도한 후 위치추적제어를 위한 슬라이딩모드제어기를 설계하였다. 제어기 설계시 이송해이블의 부하질량 변화에 대한 시스템 불확실성과 마찰력을 고려하여 제어성능의 강건성을 보장하도록 하였다. 제안된 제어시스템의 제어영역(control bandwidth)을 주파수 영역에서 고찰한 후 여러 레적에 대한 위치추적제어 실험을 수행하였다.

• Physical Therapy Korea
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• v.22 no.3
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• pp.61-70
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• 2015

To develop an effective and efficient measurement system for tracking changes of functional status across two measures, it is essential to integrate information and communicate scores across two measures. The lack of communication between two measures leads to score incompatibility. A potential solution would be the development of a crosswalk table between those measures. Prior to creating a crosswalk table, selecting common items between two measures is critical. By using the Oswestry low back pain disability questionnaire (Oswestry) and a short form measuring disability resulting from low back pain, item level statistics as well as differential item functioning (DIF) using the Rasch measurement were investigated. Eighty-two participants with known group validity were recruited. Based on the application of the Rasch measurement model, item difficulties across the two measures were logically and hierarchically ordered. Ceiling effects for both measures were detected, which were not be able to be effectively measured with the two measures. The DIF analysis across the two measures confirmed that five paired items were found to have DIF and five common items were selected for common items. Although five paired items function differently across the Oswestry and the short form, all items of both measures were well targeted study participants. The common items selected by the Rasch measurement model may be effective when creating a crosswalk table between the Oswestry and the short form.