• Research in Mathematical Education
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• v.16 no.4
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• pp.233-244
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• 2012

The purpose of this study is to investigate the relationship between creativity development and debate in solving a probability task. We developed the probability task with instructional strategies facilitating debating among students. 33 students in grade 11 who were identified as gifted participated in this study. The findings indicated that debating leads students to critical and reflective thinking on prior learning regarding probability concepts, which nurtured creative ideas on sample space.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.102-111
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• 2005

In this paper, we address a position control for a parallel stage, which is levitated and driven by electric magnetic force. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion by the vertical and horizontal force. A dynamic equation of the stage system is derived based on Newton-Euler method and it's special Jacobian matrix describing a relation between the limited velocity and Cartesian velocity is done. There are proposed two control methods for positioning which are Cartesian space controller and Actuator space controller. The control performance of the Cartesian space controller is better than the Actuator space controller in task space trajectory while the Actuator space controller is simpler than the Cartesian space controller in controller realization.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.364-367
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• 2004

This paper presents the flight software of KoDSat (KSLV-l Demonstration Satellite) which performs demonstrating the KSLV-l (Korea Space Launch Vehicle-l)'s satellite launch capability. The KoDSat Flight Software executes in a single-processor, multi-function flight computer on the spacecraft, the OBC (On Board Computer). The flight software running on the single processor is responsible for all real-time processing associated with: processor startup and hardware initialization, task scheduling, RS422 handling function, command and data handling including uplink command and down-link telemetry, attitude determination and control, battery state of charge monitoring and control, thermal control processing.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1136-1139
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• 1996

For on-line trajectory planning such as teleoperation it is desirable to keep good manipulability of the robot manipulators since the motion command is not given in advance. To keep good manipulability means the capability of moving any arbitrary directions of task space. An optimization process with different manipulability measures are performed and compared for a redundant robot system moving in 2-dimensional task space, and gives results that the conventional manipulability ellipsoid based on the Jacobian matrix is not good choice as far as the optimal direction of motion is concerned.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.587-590
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• 2005

Reactive plans for a box-pushing task of a mobile robot are automatically built up, where sequential action plans are found in a configuration space by A* algorithm for various initial configurations. Then, conjunction of conditions to associate with a same behavior are found by a back tracking algorithm. And corresponding reactive plans are generated. Finally, a clustering technique is applied to identify which reactive plan should be applied for a given perceptual condition. Several simulation results are shown to justify our proposed approach.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.10
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• pp.930-939
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• 2004

In this paper, both dynamic constraints and kinematic constraints are considered for the analysis of manipulability of robotic systems comprised of multiple cooperating arms. Given bounds on the torques of each Joint actuator for every robot, the purpose of this study is to drive the bounds of task-space acceleration of object carried by the system. Bounds on each joint torque, described as a polytope, is transformed to the task-space acceleration through matrices related with robot dynamics, robot kinematics, object dynamics, grasp conditions, and contact conditions. A series of mathematical manipulations including the procedure calculating minimum infinite-norm solution of linear equation is applied to get the reachable acceleration bounds from given actuator dynamic constrains. Several examples including two robot systems as well as three robot system are shown with the assumptions of complete-constraint contact model(or' very soft contact') and insufficient or proper degree of freedom robot.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.929-930
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• 2006

In this paper, we propose a planning algorithm which automatically generates robust behavior plans for service robots in the dynamically changing environments. The proposed method searches for paths to perform the given tasks in the physical space and the configuration space where tasks are described. And then, the characteristics of paths for successfully performed task are abstracted and generalized to build an ordered-tree structure. The resulting robust behavior plans guarantee that the given tasks are successfully performed. The validity of our method is tested by simulation work for a pushing-box task.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.925-926
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• 2006

In the multi-agent system for a single task, the action selection can be made for the real-time environment by using the global coordination space, global coordination graph and MAX-PLUS algorithm. However, there are some difficulties in multi-agent system for multi-tasking. In this paper, a real-time decision making method is suggested by using coordination space, coordination graph and dynamic coordinated state of multi-agent system including many agents and multiple tasks. Specifically, we propose locally dynamic coordinated state to effectively use MAX-PLUS algorithm for multiple tasks completion. Our technique is shown to be valid in the box pushing simulation of a multi-agent system.

• The Journal of the Acoustical Society of Korea
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• v.26 no.1E
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• pp.21-26
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• 2007

In this paper, we propose a modified Viterbi algorithm to compensate for endpoint detection error during the decoding phase of an isolated word recognition task. Since the conventional Viterbi algorithm explores only the search space whose boundaries are fixed to the endpoints of the segmented utterance by the endpoint detector, the recognition performance is highly dependent on the accuracy level of endpoint detection. Inaccurately segmented word boundaries lead directly to recognition error. In order to relax the degradation of recognition accuracy due to endpoint detection error, we describe an unconstrained search of word boundaries and present an algorithm to explore the search space with efficiency. The proposed algorithm was evaluated by performing a variety of simulated endpoint detection error cases on an isolated word recognition task. The proposed algorithm reduced the Word Error Rate (WER) considerably, from 84.4% to 10.6%, while consuming only a little more computation power.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.347-352
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• 2022

The paper presents how to update impedance control parameters for dual-arm manipulators using EMG signals and motions of the operator. Since the hand motions of the dual-arm are modeled to be the mass-spring-damper system in this paper, the impedance parameter update method is an important issue to reflect the operator's force. However, task space inertia to be used as the mass parameter goes to infinity if the manipulator approaches a kinematic singularity. To alleviate this issue, the impedance (stiffness and damping) parameters are divided with a diagonal element of the task space inertia. Also, the stiffness and damping matrices are updated using the normalized EMG signals captured from the operator's forearm. Through this process, the motion of the dual-arm manipulator is more stabilized even though it approaches the kinematic singularity.