• Proceedings of the KSR Conference
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• 2002.10b
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• pp.1029-1034
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• 2002

Object of this paper are numerical and experimental evaluation of Korean Standard Train Loading(L-loading scheme) with respect to UIC's and real train loading, quantitative formulation of the real train types in South Korea. These objects are require to changing environment of train operation, for example, high density traffic and gradual train speed increase. For the reasonable repair, reinforcement and rehabilitation of existing railway infrastructures, statistical analysis of the loading effect during the long term experiment in conventional lines have to conduct. Statistical quantitative formulation of the loading case need to consistency numerical evaluation of the railway safety. Hereafter, those results will be core technical data for the economy enhancement of international line construction. Further, these results are using to make track maintenance criterions for transcontinental, speed up railway and revision of standard train leading diagram.

• The Journal of the Acoustical Society of Korea
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• v.18 no.2E
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• pp.18-23
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• 1999

This paper proposes a method of separately determining three intrinsic mechanical parameters of an unknown object in the framework of ultrasound inverse scattering tomography. Those parameters are the speed of sound, density, and absorption whose values are given as the solution of an inhomogeneous Helmholtz wave equation. The separate reconstruction method is mathematically formulated, the integral equations are discretized using the sinc basis functions, and the Newton-Raphson method is adopted as a numerical solver in a measurement configuration where the object is insonified by an incident plane wave over 360˚ and the scattered field is measured by detectors arranged in a rectangular fashion around it. Two distinct frequencies are used to separate each parameter of three Gaussian objects that are either located at the same position or separately from each other. Computer simulation results show that the separate reconstruction method is able to separately reconstruct the three mechanical parameters. The absorption parameter turns out to be a little difficult to reconstruct as compared with the other two parameters.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.3
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• pp.149-154
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• 2002

In this paper, we propose a new graphic deformation algorithm for haptic interface system. Our deformable model is based on non-linear elasticity, anisotropy behavior and the finite element method. Also we developed controller for high-speed communication. The proposed controller is based on the PCI/FPGA technology, which could progress the capability of the position calculating and the force data transmitting. The haptic system is composed of the 6DOF force display device, the high-speed controller, HIR library for 3D graphic deformation algorithm and the haptic rendering algorithm. The developed system will be used on constructing the dynamical virtual environment. We demonstrate the relevance of this approach for the real-time simulating deformations of elastic objects. To show the efficiency of our system, we programmed the simulation of force reflecting. As the result of experiment, we found that it has high stability and easy to control for deformable object than some other systems.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.2
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• pp.120-125
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• 2010

This paper proposes an intelligent PID/Fuzzy control system for two humanoid robots to transport objects stably. When a robot transports an object while walking, a whole body system of a robot may not be stable due to vibration or external factors from a different departure speed error and a body movement of walking robots. Therefore, it is necessary to measure the horizontal and vertical locations and speeds of object, then calibrate the difference of departure speed between robots with PID/Fuzzy control. The results of simulation with two robots indicated that a proposed controller makes robots to transport an object stably.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1007-1010
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• 2003

Efficient using of web cache is becoming important factor that decide system management efficiency in web-Based system. Cache performance depends heavily on replacement algorithms, which dynamically select a suitable subset of objects for caching in a finite space. However, replacement algorithm on web cache has many differences than traditional replacement algorithm. In this paper, a web-caching algorithm is proposed for efficient operation of web base system. The algorithm is designed based on a divided scope that considered size reference characteristic and heterogeneity on web object. The performance of the algorithm is analyzed with an experiment. With the experiment results, the algorithm is compared with previous replacement algorithms, and its performance is confirmed ith an improvement of response speed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.62-69
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• 2002

With the development of CUP speed and graphic technology, real-time simulation of deformable object is embossed as an essential issue in engineering field. Recently, it has been applied to the surgical training and game animation with haptic force feedback. But real time simulation of deformable objects is not easy because of the conflicting demands of speed and low latency and physical accuracy. In this study, we present the implementation of boundary element method(BEM) which is combined with the nonuniform B-spline surface. It is working together with the real-time simulation technique and the geometry data is altered by handling control points without preprocessing routine.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.67-71
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• 2002

In this paper, we propose a new deformable model based on non-linear elasticity, anisotropic behavior and the finite element method and developed the high-speed controller for haptic control. The proposed controller is based on the PCI/FPGA technology, which can calculate the real position and transmit the force data to device rapidly, The haptic system is composed of 6DOF force display device, high-speed controller and HIR library for 3D graphic deformation algorithm & haptic rendering algorithm. The developed system will be used on constructing the dynamical virtual environment. we demonstrate the relevance of this approach for the real-time simulating deformations of elastic objects. To show the efficiency of our system, we designed simulation program of force-reflecting, As the result of the experiment, we found that the controller has much higher resolution than some other controllers.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.42-46
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• 2018

In this paper, we propose fast object detection method of the cars by applying YOLOv2(You Only Look Once version 2) and UAVs (Unmanned Aerial Vehicles) while on the highway. We operated Darknet, OpenCV, CUDA and Deep Learning Server(SDX-4185) for our simulation environment. YOLOv2 is recently developed fast object detection algorithm that can detect various scale objects as fast speed. YOLOv2 convolution network algorithm allows to calculate probability by one pass evaluation and predicts location of each cars, because object detection process has simple single network. In our result, we could find cars on the highway area as fast speed and we could apply to the real time.

• Journal of Korean Association for Spatial Structures
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• v.15 no.3
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• pp.61-68
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• 2015

A study on BRP(Building Rapid Printing) technology is in an initial stage although general 3d printers are being developed in a great speed and with fruitful outputs. Even some laboratories in advanced countries have difficulties in their research due to many technological restrictions and have not produced a practical output yet. This paper proposed distinct directions in which the research of this aera should be developed and this manifested four areas - printing speed, reinforcing tech, material tech and nozzle tech and those areas were proposed with concrete development alternatives and objects.

• Physical Therapy Korea
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• v.29 no.4
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• pp.262-268
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• 2022

Background: Virtual reality (VR) programs based on motion capture camera are the most convenient and cost-effective approaches for remote rehabilitation. Assessment of physical function is critical for providing optimal VR rehabilitation training; however, direct muscle strength measurement using camera-based kinematic data is impracticable. Therefore, it is necessary to develop a method to indirectly estimate the muscle strength of users from the value obtained using a motion capture camera. Objects: The purpose of this study was to determine whether the pedaling speed converted using the VR engine from the captured foot position data in the VR environment can be used as an indirect way to evaluate knee muscle strength, and to investigate the validity and reliability of a camera-based VR program. Methods: Thirty healthy adults were included in this study. Each subject performed a 15-second maximum pedaling test in the VR and built-in speedometer modes. In the VR speedometer mode, a motion capture camera was used to detect the position of the ankle joints and automatically calculate the pedaling speed. An isokinetic dynamometer was used to assess the isometric and isokinetic peak torques of knee flexion and extension. Results: The pedaling speeds in VR and built-in speedometer modes revealed a significantly high positive correlation (r = 0.922). In addition, the intra-rater reliability of the pedaling speed in the VR speedometer mode was good (ICC [intraclass correlation coefficient] = 0.685). The results of the Pearson correlation analysis revealed a significant moderate positive correlation between the pedaling speed of the VR speedometer and the peak torque of knee isokinetic flexion (r = 0.639) and extension (r = 0.598). Conclusion: This study suggests the potential benefits of measuring the maximum pedaling speed using 3D depth camera in a VR environment as an indirect assessment of muscle strength. However, technological improvements must be followed to obtain more accurate estimation of muscle strength from the VR cycling test.