• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.84-93
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• 2011

In order to provide the real time and proper information to the pedestrian who is using the transport connection and transfer center through data collecting and processing process, the design of the test-bed (Gimpo airport)'s communication construction and the technology of the pedestrian location tracking has been researched. The design of the communication construction should make sure that it can provide believable data to the user of the transfer center. At the same time, the location tracking should also be considered, so that the require of the communication efficiency and the location tracking efficiency can be met together. In order to make the efficient location tracking technology, the problems related to the commercial technology based real time location identification will be resolved and the new approach method was proposed and be applied and analysed to the test-bed. The wireless access points can be located in the most real-world situation which has added the characteristics of the real building to the electronic map, and through the analysis of theirs location, they can be set as the mainly necessary points for the communication construction design and the location tracking and the method to locate that points has been proposed. How to set, how to apply it to the test-bed and the examination result will be introduced in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4B
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• pp.232-241
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• 2008

In this paper, for analysing the major factors giving the effect to the quality of video on the multicasting service of IPTV, we construct the lab test network environment similar to the real IPTV service network environment. We measure the quality of video on the multicasting of IPTV generating and increasing the broadcasting traffic on the situation that apply the QoS technique to the test lab network and not apply the QoS technique and then find out the threshold value of factors giving the effect to the quality of video on the multicasting service of IPTV. This paper can be used in basic date for guaranteeing the constant video quality on the multicasting service of IPTV.

• Journal of the Ergonomics Society of Korea
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• v.24 no.4
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• pp.55-62
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• 2005

This study examined the effect of ergonomic heel rest that was designed for drivers who have physical handicap in the low leg muscles or have to drive prolonged hours with frequent foot pedaling. An experiment was designed to test the ergonomic heel rest with traditional foot pedal. Forty subjects participated in the experiment. Electromyography(EMG) was used to monitor the muscle activity and fatigue of right leg, and Electro-goniometer was used to measure the ranges of motions of the knee and ankle. A simulator of driver's seat was built for the experiment and the heel rest was installed on it. In order to examine the low muscle activity and range of motion, subjects used the foot pedal for 15 minutes repetitively for each experimental condition. Another 15 minutes test without the heel rest was also performed for comparison. The Root Mean Square(RMS) and Mean Power Frequency(MPF) Shift were used to quantify the level of muscle activity and local muscle fatigue. In results, statistically significant decreases of muscle activity and fatigue were found in all the low leg muscles. The range of motion of the knee and ankle joint also decreased when the heel rest was used. The mechanism of the heel rest effect was discussed in this study. This type of heel rest can be applied to real driving situation after ensuring the safety, or overcoming the psychological discomfort possibly due to unfamiliarity.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2407-2409
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• 2005

As the cumulative amount of spent fuel increases, the reliable and effective management of the spent fuel has become a world-wide mission. For this mission, KAERI is developing the Advanced Spent Fuel Conditioning Process (ACP) as a pre-disposal treatment process for spent fuel. Conventional approach to the development of the process and the remote operation technology is to fabricate the process equipment on the same scale as the real environment and demonstrate the remote handling operation using simulated fuel called a mock-up test. But this mock-up test is expensive and time consuming, since the design may need to be modified and the equipment fabricated again to account for the problems found during a testing. To deal with this problem, we developed a digital mockup for the ACP. Also, for an effective utilization of the digital mockup, we developed user interface modules such as the data acquisition and display module and the external input device interface module. The result of this implementation shows that a continuous motion of the manipulator using the external device interface can be represented easily and the information display screens responded well to the simulation situation.

• Research in Mathematical Education
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• v.4 no.1
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• pp.1-22
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• 2000

The purpose of this study was to investigate the effects of using graphing calculators on students' understanding of the linear and quadratic function concepts. The populators of this study are tenth graders at high school in Seoul, one class for the treatment group and another class for the comparison group, and experiment period is 14 weeks including two weeks for school regular exams.Function tests used in the study was proposed which described a conceptual knowledge of functions in terms of the following components: a) Conceptual understanding, b) Interpreting a function in terms of a verbal experission, c) Translating between different representations of functions, and d) Mathematical modeling a real-world situation using functions. Even though the group test means of the individual components of conceptual understanding, interpreting, translating, mathematical modeling did not differ significantly, there is evidence that the two groups differed in their performance on conceptual understanding. It was shown that students learned algebra using graphing calculators view graphs more globally. The attitude survey assessed students' attitudes and perceptions about the value of mathematics, the usefulness of graphs in mathematics, mathematical confidence, mathematics anxiety, and their feelings about calculators. The overall t-test was not statistically significant, but the students in the treatment group showed significantly different levels of anxiety toward mathematics.

• Korean Journal of Computational Design and Engineering
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• v.13 no.6
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• pp.429-439
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• 2008

With a remote operated manipulator system, the situation at a remote site can be rendered through remote visualized image to the operator. Then the operator can quickly realize situations and control the slave manipulator by operating a master input device based on the information of the virtual image. In this study, the remote operator visual support system (ROVSS) was developed for viewing support of a remote operator to perform the remote task effectively. A visual support model based on virtual environment was also inserted and used to fulfill the need of this study. The framework for the system was created by Windows API based on PC and the library of 3D graphic simulation tool such as ENVISION. To realize this system, an operation test environment for a limited operating site was constructed by using experimental robot operation. A 3D virtual environment was designed to provide accurate information about the rotation of robot manipulator, the location and distance of operation tool through the real time synchronization. In order to show the efficiency of the visual support, we conducted the experiments by four methods such as the direct view, the camera view, the virtual view and camera view plus virtual view. The experimental results show that the method of camera view plus virtual view has about 30% more efficiency than the method of camera view.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.53-63
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• 2013

To guide the decision making of the expert engineer specialized in power system operation and control; the practical OPF solution should take in consideration the critical situation due to severe loading conditions and fault in power system. Differential Evolution (DE) is one of the best Evolutionary Algorithms (EA) to solve real valued optimization problems. This paper presents simple Differential Evolution (DE) Optimization algorithm to solving multi objective optimal power flow (OPF) in the power system with shunt FACTS devices considering voltage deviation, power losses, and power flow branch. The proposed approach is examined and tested on the standard IEEE-30Bus power system test with different objective functions at critical situations. In addition, the non smooth cost function due to the effect of valve point has been considered within the second practical network test (13 generating units). The simulation results are compared with those by the other recent techniques. From the different case studies, it is observed that the results demonstrate the potential of the proposed approach and show clearly its effectiveness to solve practical OPF under contingent operation states.

• Journal of Power Electronics
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• v.11 no.4
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• pp.471-478
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• 2011

This paper addresses the establishment of a kVA-range plug-in hybrid electrical vehicle (PHEV) integration test platform and associated issues. Advancements in battery and power electronic technology, hybrid vehicles are becoming increasingly dependent on the electrical energy provided by the batteries. Minimal or no support by the internal combustion engine may result in the vehicle being occasionally unable to recharge the batteries during highly dynamic driving that occurs in urban areas. The inability to sustain its own energy source creates a situation where the vehicle must connect to the electrical grid in order to recharge its batteries. The effects of a large penetration of electric vehicles connected into the grid are still relatively unknown. This paper presents a novel methodology that will be utilized to study the effects of PHEV charging at the sub-transmission level. The proposed test platform utilizes the power hardware-in-the-loop (PHIL) concept in conjunction with high-fidelity PHEV energy system simulation models. The battery, in particular, is simulated utilizing a real-time digital simulator ($RTDS^{TM}$) which generates appropriate control commands to a power electronics-based voltage amplifier that interfaces via a LC-LC-type filter to a power grid. In addition, the PHEV impact is evaluated via another power electronic converter controlled through $dSPACE^{TM}$, a rapid control systems prototyping software.

• Convergence Security Journal
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• v.21 no.1
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• pp.45-53
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• 2021

When the security monitoring system is performed in a separation network, there is little normal anomaly detection in internal networks or high-risk sections. Therefore, after the establishment of the security network, a model is needed to evaluate state-of-the-art cyber threat anomalies for internal network in separation network to complete the optimized security structure. In this study, We evaluate it by generating datasets of cyber vulnerabilities and malicious code arising from general and separation networks, It prepare for the latest cyber vulnerabilities in internal network cyber attacks to analyze threats, and established a cyber security test evaluation system that fits the characteristics. The study designed an evaluation model that can be applied to actual separation network institutions, and constructed a test data set for each situation and applied a real-time security assessment model.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.473-483
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• 1998

A learner's cognitive conflict with his /her existing conception is regarded to be one of the most important factors for a conceptual change. In this study, the effects of the conflict situation types on inducing students' cognitive conflicts in Newton's law were examined. The thirty-four students of 10th grade were selected from a rural high school based on the result of pre-test. The two different types of conflict situations among many possible types were used in this study. One type was using logical conflict situation and the other was demonstrating real conflict situation. The levels of cognitive conflict were measured by 4-point Likert scale by three interviewers. As the results, the demonstration method was more effective than the logical argument method. In case of the logical argument method, rather than showing scientific conceptions, suggesting another misconception was more effective to the students who have misconception. However, logical argument method was not effective to those who have scientfic conceptions. To the students who have unscientific conceptions, the demonstration method was very effective for inducing cognitive conflict. From the results of this study, demonstration method of teaching seems to be very effective for inducing students' cognitive conflict and overcoming their misconceptions on scientific concept.