• Journal of Positioning, Navigation, and Timing
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• v.13 no.2
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• pp.167-177
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• 2024

The Korea Augmentation Satellite System (KASS) has been certified by the Ministry of Land, Infrastructure and Transport (MOLIT) and commenced Safety-of-Life (SoL) service at the end of 2023. KASS complies with the APV-I signal-in-space performance requirements defined in the International Civil Aviation Organization (ICAO) Standards and Recommendation Practices (SARPs). The performance of KASS is verified through two steps. In the first step, design conformity from the aspect of performance is verified by both review and analysis of design and simulation. In the second step, operational conformity is tested and assessed by operational testing using real data and a deployed system with operational SWs and configurations. This paper presents a methodology, a procedure and results for the KASS operational testing. Finally, performance degradation events and results by month and region during the operational testing are presented and analyzed.

• English Language & Literature Teaching
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• no.3
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• pp.43-54
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• 1997

According to Asher(1972) listening skill must be taught before any other skills. Despite such an importance of listening skill, listening tests taken at the secondary schools depend on simple multiple choice method. So more various method such as Task-Based Listening Test need suggesting. This study aims at (1) three step listening material development (2) and advancement of listening ability through the materials.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.749-752
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• 2003

The HLA is defined by three components: (1) Rules, (2) the HLA Interface Specification, and (3) the Object Model Template(OMT). The RTI(Run-Time Infrastructure) software implements the interface specification. It provides services in a manner that is comparable to the way a distributed operating system provides services to applications. A way to test whether is suitable for a standard, and all service was implemented is tested through two phases of processes to verify the RTI which proposed in DMSO. In this paper, we discuss Level One Test Procedures and a method. Confirms whether RTI was implemented in Interface Specification according to Level One Test Procedures appropriately through a test. Develops Test Suite for every each step to test whether a correct command and the expected results are occur.

• Journal of the Korean Data and Information Science Society
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• v.24 no.3
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• pp.593-601
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• 2013

We often need to include categorial variables as explanatory variables in regression models. The categorial variables in regression models can be quantified through dummy variables. In this study, we provide an education tool using Excel VBA for displaying regression lines along with test results for regression models with a continuous explanatory variable and one or two categorical explanatory variables. The regression lines with test results are provided step by step for the model(s) with interaction(s), the model(s) without interaction(s) but with dummy variables, and the model without dummy variable(s). With this tool, we can easily understand the meaning of dummy variables and interaction effect through graphics and further decide which model is more suited to the data on hand.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1258-1259
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• 2011

LSMs are installed under girders along the long track. In order to improve the efficiency of the LSM, long stator LSM should be divided into the specified length and the propulsion inverters should have the system topology to generate high voltage and current for LSMs. This paper presents a system topology with two-step inverter in order to generate high voltage in inverter. A LSM propulsion system is developed and implemented in Maltab/Simulink. A system model of the two-step Inverter is applied to developed model. This paper demonstrates through simulation, advantages of multi-step inverter. The conclusions can serve the design of LSM propulsion system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.135-142
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• 2004

Two-step identification approach for effective bridge health monitoring is proposed to alleviate the issues associated with many unknown parameters faced in the real structures and to improve the accuracy in the estimate results. It is suitable for on-line monitoring scheme, since the damage assessment is not always needed to be carried out whereas the alarming for damages is to be continuously monitored. In the first step for screening potential damaged members, damage indicator method based on modal strain energy, probabilistic neural networks and the conventional neural networks using grouping technique are used and then the conventional neural network technique is utilized for damage assessment on the screened members in the second step. The proposed methods are verified through a field test on the northern-most span of old Hannam Grand Bridge.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.911-919
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• 2013

This paper reports the development of test bed with the energy recovering technique using two-step boost converter. The device is utilized for LDC aging test of Hyundai Motor's LPI AVANTE HEV in mass production. The developed power recycle type test bed is designed as 1.5 kW class to test up to the maximum load power of LDC and is also designed to supply scant power supply up to 500 W after power recycle. The theoretical design analysis and operational characteristics analysis results of test bed are reported, and its practicality and reliability are verified through the test result. Also, the finally developed test bed confirms approximately 79~85 % energy saving effect compared to the usual traditional aging test system.

• The Journal of the Acoustical Society of Korea
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• v.18 no.1
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• pp.16-24
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• 1999

Design of SAW ladder filters has been performed by a rather trial and error method, that is, by modifying the design variables step by step until designed performance of the filter satisfies given specifications. In this work, optimal design method has been developed that automatically determines the detailed pattern of the SAW ladder filter to meet the specification once desired performance is given. As a first step for the development, the analysis tool for the SAW ladder filter has been produced by means of the Smith equivalent circuit analysis technique, and its validity has been verified through comparison of its calculation result with experimental data. With the analysis tool, we have investigated the performance variation of the filter with the change of its design factors, and the result has led to the optimal design algorithm. Validity and efficiency of the algorithm has been checked through test design of several SAW ladder filter samples on the market.

• Journal of Korean Elementary Science Education
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• v.25 no.1
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• pp.27-38
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• 2006

The purpose of this study was to develop a test of a creative problem solving (CPS) for the selection of gifted science students in elementary school. For this, the methods and procedures of the selection of gifted science students was investigated through the internet homepages 23 gifted science education centers of universities and 16 city. province offices of education. The results of this study were as follows: Most of the gifted science students were selected through a multi-step examination process. They were selected on the basis of their records by recommendation of a principal or a classroom teacher in their school, by operation of standardized tests (ex. intelligence quotient score, achievements in science and mathematics, interest and attitude/aptitude for science as well as through other means), as well as through intensive observation of those gifted science students who are selected by interview and oral tests. The selection of gifted students was not evaluated through creativity testing; giftedness in city. province office of education. Testing of CPS was found to be especially lacking in these organizations. For the development of the test items of CPS in science, the five elements were extracted through the framework for the content analysis of the CPS: problem exploration, problem statement, solution thinking, experiment design, and assesment. In addition, suggestions were made regarding an appropriate scoring system for the test of the CPS. As the result of the developed test was applied to the 4th grade of the gifted and general student, we found that gifted students were superior to general students. In conclusion, it was that the CPS test developed in this study should be used to evaluate the CPS for the selection of gifted students.

• Journal of the Ergonomics Society of Korea
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• v.19 no.1
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• pp.63-76
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• 2000

In this study, the factors affecting reality aspect of virtual reality system were identified through Quality Function Deployment. The influence of some selected factors was evaluated in simulated performance test. It was shown that the factor of whether user can break through the objects in virtual space is the most sensitive to performance, followed by the factors of rotation angle and movement step. Also, the results implied that as more referents were provided to user, feeling of reality was enhanced.