• Industrial Engineering and Management Systems
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• v.8 no.2
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• pp.109-120
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• 2009

As the use of 3DCAD data became widespread in designing products in manufacturing, attempts have been made to shorten lead time and reduce cost of production preparation utilizing 3DCAD data for launching assembly lines. In order to create assembly plans not only efficient but easy for operators to operate ('easy-to-operate'), this study presents approaches, methods, and systems for creating 3DCGAs (3 Dimensional Computer Graphic Animations) which automatically utilize a prototype-free production preparation methodology. Characteristics of this study include that it proposes the methodology for creating assembly operation 3DCGAs automatically, for all the possible assembly operations corresponding each of the possible assembly sequences first. Using the created 3DCGAs, the study next considers assembly methods by evaluating how easy or 'operator friendly' they are in implementing, and devises tools or jigs to be used, and plans efficient assembly line organization. The concept of the methodology was formed by focusing on the value-adding assembly steps at which parts turn into products directly. The study also validates the effectiveness of the presented methodology by employing the methods used in actual production preparation process in businesses, and proves that an efficient assembly line can be organized in a shorter period of time utilizing the developed system and by preparing easy-to-operate and efficient plans in 3DCGAs at the design stage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1709-1715
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• 2005

This paper describes the development of 3-D web graphic library for dynamic web graphic design. The 3-D web graphic library developed in this per supports creation of 3-D objects like cube and sphere objects, elimination of hidden line and surface, and the shading of diffuse and specular reflections. It provides, in drawing, perspective projection of an object depth first sort of multiple objects, and wire frame and solid models. It also supports texture mapping function for realistic and dynamic web application in application software. Each created 3-D object gives functions for the scaling, translation, and rotation of itself. It can be used for the development of dynamic web application software and the advertisement of information for business and tourism as a 3-D web graphic library engine. It is written in 'Java' language and runs on web browsers with Java virtual machine without any dependancy of client computer system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1456-1461
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• 2003

Recently, the quantity of using information go on increasing geometric-progression. At the same time, the management of information is effected on the most organization's effective operation so that many user call for the powerful equipment which expound. access more information. As information searching technology is concentrated about the object of information based on a letter mainly, an effective searching technology for the object of multimedia such as a still image, a video and a sound must be studied. As a monitor of computer is 2-D, it difficult for one to grasp the whole aspect at a look glance like a library. Accordingly, some condition is necessary. First, it acquired the virtual video, turning a camera around by 30 degrees with a camera of 15mm lens, giving a warping and distortion. Second, it improved the books for user to search easily, adding to the video in existing books information system. The original text suggests some way which can embody the video searching technology under the base of personal computer.

• The KIPS Transactions:PartA
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• v.19A no.3
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• pp.147-154
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• 2012

The higher thinking skills, such as creativity and problem-solving about a given problem, are difficult to assess and diagnose. For an accurate diagnosis of these higher thinking abilities, we need to fully observe learner's problem-solving process or learner's individual reports. However, in an online learning or virtual class environments, evaluation of learner's problem-solving process becomes more difficult to diagnose. The best way to solve this problem is through reporting by tracking learner's actions when he tries to solve a problem. In this study, we developed a module which can evaluate and diagnose student's problem-solving ability by tracking actions in MS-Office suite, which is used by students to solve a given problem. This module performs based on the learner's job history through user tracking. To evaluate the effectiveness of this diagnostic module, we conducted satisfaction survey from students who were preparing the actual MOS exams. As a result, eighty-one (81) of the participants were positive on the effectiveness of the learning system with the use of this module.

• Journal of Power Electronics
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• v.16 no.1
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• pp.297-309
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• 2016

Grid-connected inverters (GCIs) with an LCL output filter have the ability of attenuating high-frequency (HF) switching ripples. However, by using only grid-current control, the system is prone to resonances if it is not properly damped, and the current distortion is amplified significantly under highly distorted grid conditions. This paper proposes a synchronous reference frame equivalent proportional-integral (SRF-EPI) controller in the αβ stationary frame using the parallel virtual resistance-based active damping (PVR-AD) strategy for grid-interfaced distributed generation (DG) systems to suppress LCL resonance. Although both a proportional-resonant (PR) controller in the αβ stationary frame and a PI controller in the dq synchronous frame achieve zero steady-state error, the amplitude- and phase-frequency characteristics differ greatly from each other except for the reference tracking at the fundamental frequency. Therefore, an accurate SRF-EPI controller in the αβ stationary frame is established to achieve precise tracking accuracy. Moreover, the robustness, the harmonic rejection capability, and the influence of the control delay are investigated by the Nyquist stability criterion when the PVR-based AD method is adopted. Furthermore, grid voltage feed-forward and multiple PR controllers are integrated into the current loop to mitigate the current distortion introduced by the grid background distortion. In addition, the parameters design guidelines are presented to show the effectiveness of the proposed strategy. Finally, simulation and experimental results are provided to validate the feasibility of the proposed control approach.

• The Transactions of the Korea Information Processing Society
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• v.7 no.10
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• pp.3138-3147
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• 2000

EC(Electronic Commerce) which is cone the virtual space through Internet, has the advantage of time and space. On the contrary, it also has weak point like security probelm because anybody can easily access to the system due to open network attribute of Internet. Theretore, we need the solutions that protect the EC security problem for safe and useful EC activity. One of these solution is the implemonlation of a strong cipher algorithm. YK2(YoungKu Kang) cipher algorithm proposed in this paper is advantage for the EC security and it overcomes the limit of the current 6/1 bits block cipher algorithm using 128 bits key length for input, output, encryption key and 32 rounds. Moreover, it is degigned for the increase of time complexity and probability calculation by adapting more complex design for key scheduling regarded as one of the important element effected to enciyption.

• The Journal of Korea Robotics Society
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• v.1 no.1
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• pp.17-24
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• 2006

Though the final goal of mobile robot navigation is to be autonomous, operators' intelligent and skillful decisions are necessary when there are many scattered obstacles. There are several limitations even in the camera-based tele-operation of a mobile robot, which is very popular for the mobile robot navigation. For examples, shadowed and curved areas cannot be viewed using a narrow view-angle camera, especially in bad weather such as on snowy or rainy days. Therefore, it is necessary to have other sensory information for reliable tele-operations. In this paper, sixteen ultrasonic sensors are attached around a mobile robot in a ring pattern to measure the distances to obstacles. A collision vector is introduced in this paper as a new tool for obstacle avoidance, which is defined as a normal vector from an obstacle to the mobile robot. Based on this collision vector, a virtual reflection force is generated to avoid the obstacles and then the reflection force is transferred to an operator who is holding a joystick to control the mobile robot. Relying on the reflection force, the operator can control the mobile robot more smoothly and safely. For this bi-directional tele-operation, a master joystick system using a hall sensor was designed to resolve the existence of nonlinear sections, which are usual for a general joystick with two motors and potentiometers. Finally, the efficiency of a force reflection joystick is verified through the comparison of two vision-based tele-operation experiments, with and without force reflection.

• The Korean Journal of Cytopathology
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• v.19 no.2
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• pp.65-71
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• 2008

In Korea, the quality control(QC) program forcytopathology was introduced in 1995. The program consists of a checklist for the cytolopathology departments, analysis data on all the participating institutions' QC data, including the annual data on cytologic examinations, the distribution of the gynecological cytologic diagnoses, as based on The Bethesda System 2001, and the data on cytologic-histolgical correlation of the gynecological field, and an evaluation for diagnostic accuracy. The diagnostic accuracy program has been performed 3 times per year with using gynecological, body fluid and fine needle aspiration cytologic slides. We report here on the institutional QC data and the evaluation for diagnostic accuracy since 2004, and also on the new strategy for quality control and assurance in the cytologic field. The diagnostic accuracy results of both the participating institutions and the QC committee were as follows; Category 0 and A: about 94%, Category B: 4-5%, Category C: less than 2%. As a whole, the cytologic daignostic accuracy is relatively satisfactory. In 2008, on site evaluation for pathology and cytology laboratories, as based on the "Quality Assurance Program for Pathology Services" is now going on, and a new method using virtual slides or image files for determining the diagnostic accuracy will be performed in November 2008.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.8-15
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• 2007

Freeway corridors consist of urban freeways and parallel arterials that drivers can use alternatively. Ramp metering in freeways and signal control in arterials are contemporary traffic control methods that have been developed and applied in order to improve traffic conditions of freeway corridors. However, most of the existing studies have focused on either optimal ramp metering in freeways, or progression signal strategies between arterial intersections. There have been no traffic control systems in Korea that integrates the freeway ramp metering and arterial signal control. The effective control strategies for freeway operations may cause negative effects on arterial traffic. On the other hand, traffic congestion and bottleneck phenomenon of arterials due to the increasing peak-hour travel demand and ineffective signal operation may generate an accessibility problem to freeway ramps. Thus, the main function of the freeway which is the through-traffic process has not been successful. The purpose of this study is to develop an integrated control model that connects freeway ramp metering systems and signal control systems in arterial intersections. And Optimization of integrated control model which consists of ramp metering and signal control is another purpose. The design of experiment, neural network, and simulated annealing are used for optimization.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.5
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• pp.393-400
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• 2017

A virtual simulation test program to carry out the handling qualities of unmanned Rotorcraft has developed by using the MATLAB GUIDE(Graphic User Interface Development Environment). The handling quality evaluation program based on ADS-33E contributes to design the flight control system and to evaluate handling qualities. In addition, Linear Quadratic Tracker with Integrator(LQTI) attitude controller based on Linear Quadratic Regulator(LQR) for to rotorcraft BO-105C and the effects of the handling qualities is analyzed change to weight matrices of the Q and R.