• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1780-1783
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• 2005

In this paper ZMP was considered in order to get a walking stability, so the gait in the stable domain was realized through putting the stability margin in the sole domain of a foot. It is assumed that the robot's legs have 12 joints to operate a open-loop drive and there was no external disturbance under walking phases, additionally, the robot is walking on the flat plane. It was observed that the robot's walking trajectory, locus of COM and ZMP after imposing the motion to each joint. For realizing the simulation considering ZMP and movement of mass center, it was checked if it is stable for the constraint robot model to walk in stability and the feasibility was estimated about its dynamic gait. Eventually it was shown that a constraint gait algorithm is able to realize. To verify the proper walking process, ZMP(Zero Moment Point) theory is applied and the simulation has been done by ADAMS.

• Korean Institute of Interior Design Journal
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• v.13 no.3
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• pp.171-178
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• 2004

A thesis presented on the study of visitors circulation character, and components in an exhibition space in museums. A behavior ethogram is an investigational tool of tracing examination of visitors. An exhibition layout and behavior characters of exhibition viewing in the configuration of exhibition space are planned by using the method of the behavior ethogram. As time goes by an expansion of a museums concept and changing roles are more extroversive and constructive than the past. It will reflect the phases of the times and show several different aspects. The reflection of the changing circumstance will have to examine an each relationship between exhibition data, exhibition spaces and visitors In the beginning of a plan of the museum. However, the study of a unique behavior pattern and character which are made by moving visitors themselves are quietly not enough studied. The exhibition layout which is considerably examined by the viewing behavior of visitors in act response and a following circulation of viewing have a lack of precise directions and examples. In short, this study ultimately represents to grasp the meaning of the behavior characters of viewing. Furthermore, the basic directions in the museums plan are carefully considered by the reflection of exhibition circulation.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.120-131
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• 2004

In this paper, we propose the method of a motion planning generation in which the movement of the 3-link leg subsystem is constrained to a slider-link and a singular posture can be easily avoided. The proposed method is the jumping control moving in vertical direction which mimics a cat's behavior. That is, it is jumping toward wall and kicking it to get a higher-place. Considering the movement from the point of constraint mechanical system, the robotic system which realizes the motion changes its configuration according to the position and it has several phases such as; ⅰ) an one-leg phase, ⅱ) in an air-phase. In other words, the system is under nonholonomic constraint due to the reservation of its momentum. Especially, in an air-phase, we will use a control method using state transformation and linearization in order to control the landing posture. Also, an iterative learning control algorithm is applied in order to improve the robustness of the control. The simulation results for jumping control will illustrate the effectiveness of the proposed control method.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.3-16
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• 2006

In the age where the Internet changes everything, even the earth has become flat. The boarders between nations, locations, times, and industries are not maningful, and no single company can do the whole process well. Therefore, various types of 'Value network' and 'Relation web' emerge for moving first and fast learning. Bort the relationship maturity model (RMM) proposed and the partnership management initiatives at SKT demonstrate that the concept is important, and that the final goal can be reached only through a series of critical outcome at each phase. In particular, recognizing as core infrastructures various online/offline channels, deep trust, and rich communications is an important finding for a successful relationship management. Also, related literatures suggest the following key factors to be influential in more that two phases: professionalism including expertise, similarity, channel capacity. Based on these findings, future efforts need to be put on the research & development of related measurement and management tools. We do hope more people dance with their partners through these efforts.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.21-27
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• 2018

The purpose of this study is to develop a SOP (Standard Operating Procedure) for a distribution board that can monitor the leakage current of a load distribution line in real time. The developed distribution board was fabricated by applying IEC 61439-1. It consists of the distribution board and an alarm device. The work process for making the distribution board was compliant with the KEMC (Korea Electrical Manufacturers Cooperative) regulations. And the AC distribution board range is 1,000 V. In addition, the voltage in DC is less than 1500 V. The distribution board receives a 3-phases and 4-wires power supply system and can supply power to the load of a maximum of 32 single or three phase distribution circuits. Also, leakage current measured on the power distribution board was used by sensors installed. The SOP of the developed distribution board consists of the installation standards for the short circuit alarm device and sensor, the surge protection device, switches and indication lamps, and other devices. The operation procedure was prepared so that each manufacturing step of the distribution board must be confirmed by the persons in charge of preparation, production, quality control and approval before moving forward to the next step.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.417-420
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• 2006

The composition and structure of dendrite phase within $Zr_{76.11}Ti_{4.20}Cu_{4.51}Ni_{3.16}Be_{1.49}Nb_{10.53}$ bulk metallic glass (BMG) were confirmed by using an EPMA, XRD and TEM, respectively. The chief elements of dendrite phase were Zr-Ti-Nb and had a BCC structure. The thermal properties of this BMG have been then subsequently investigated by using a differential scanning calorimeter (DSC). The glass transition and crystallization onset temperatures were determined as $339.7^{\circ}C$ and $375.8^{\circ}C$ for this alloy, respectively. Mechanical properties have also been examined by conducting a series of uniaxial compression tests at various temperatures within supercooled liquid region under the strain rates between $10^{-4}/s$ and $3{\times}10^{-2}/s$. The deformation behavior of BMG composite within supercooled liquid region is similar to one of Vit-1 exhibiting amorphous single phase alloy. The flow stresses of BMG composite, however, are entirely higher than those of Vit-1 because dendrite phases are interfere with moving of atoms.

• Journal of the Optical Society of Korea
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• v.5 no.4
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• pp.140-145
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• 2001

We present a new method of volumetric interferometer, which is intended to measure the three-dimensional coordinates of a moving object in a simultaneous way with a single optical setup. The method is based on the principles of phase-measuring interferometry with phase shifting. Two diffraction point sources, which are made of the polished ends of single-mode optical fibers are embedded on the object. Two spherical wavefronts emanate from the diffraction point sources and interfere with each other within the measurement volume. One wavefront is phase-shifted by elongating the corresponding fiber using a PZT extender. A CCD array sensor fixed at the stationary measurement station detects the resulting interference field. The measured phases are then related to the three-dimensional location of the object with a set of non-liner equations of Euclidean distance, from which the complete set of three-dimensional spatial coordinates of the object is determined through rigorous numerical computation based upon the least square error minimization.

• Journal of Power Electronics
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• v.8 no.4
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• pp.354-362
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• 2008

This paper presents neural load torque compensation method which is composed of a deadbeat load torque observer and gains compensation by a parameter estimator. As a result, the response of the PMSM (permanent magnet synchronous motor) obtains better precision position control. To reduce the noise effect, the post-filter is implemented by a MA (moving average) process. The parameter compensator with an RLSM (recursive least square method) parameter estimator is adopted to increase the performance of the load torque observer and main controller. The parameter estimator is combined with a high performance neural load torque observer to resolve problems. The neural network is trained in online phases and it is composed by a feed forward recall and error back-propagation training. During normal operation, the input-output response is sampled and the weighting value is trained multi-times by the error back-propagation method at each sample period to accommodate the possible variations in the parameters or load torque. As a result, the proposed control system has a robust and precise system against load torque and parameter variation. Stability and usefulness are verified by computer simulation and experiment.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.135-144
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• 2006

This study was to investigate the kinematic analysis to score of the Yurchenko stretch skill according to phases in a horse vaulting. For this study, 8 male national gymnasts were participated in acquiring three dimensional kinematical imagining data with four Sony PD-150 video cameras After digitizing motion, the Direct Linear Transformation(DLT) technique was employed to obtain 3-D position coordinates. The kinematic factors of the distance, velocity and angle variable were calculated for Kwon3D 3.1. The following conclusions were drawn; 1) The COG resultant velocity of the less skilled group decreased in PRF phase because the less skilled group had a larger flexion-knee angle than the skilled group in BC phase, Because the less skilled group had larger flexion-shoulder angle than the skilled group in HTO phase, At blocking movement, the body inclined a moving direction. By means of it, COG lowered 2) The skilled group had a more rapid COG's vertical velocity than the less skilled group at HTD and HTO event in HC phase, because this was performed the blocking movement with body angle and contacted on a horse vaulting small and its time short by means of contacting hands on a horse vaulting quickly. Such blocking movement made the vertical up-flight movement easy at POF phase bringing out rapid COG's vertical velocity after take off a horse vaulting.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.5
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• pp.538-542
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• 2009

Industrial manipulators have been mostly used in large companies such as automakers and electronics companies. In recent years, however, demands for industrial manipulators from small and medium-sized enterprises are on the increase because of shortage of manpower and high wages. Since these companies cannot hire robot engineers for operation and programming of a robot, intuitive teaching and playback techniques of a robot manipulator should replace the robot programming which requires substantial knowledge of a robot. This paper proposes an intuitive teaching and playback algorithm used in assembly tasks. An operator can directly teach the robot by grasping the end-effector and moving it to the desired point in the teaching phase. The 6 axis force/torque sensor attached to the manipulator end-effector is used to sense the human intention in teaching the robot. After this teaching phase, a robot can track the target position or trajectory accurately in the playback phase. When the robot contacts the environment during the teaching and playback phases, impedance control is conducted to make the contact task stable. Peg-in-hole experiments are selected to validate the proposed algorithm since this task can describe the important features of various assembly tasks which require both accurate position and force control. It is shown that the proposed teaching and playback algorithm provides high positioning accuracy and stable contact tasks.