• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.660-664
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• 2003

The optimal thickness distribution of an active damping layer is sought so that it satisfies a certain constraint on the dynamic performance of a system minimizing control efforts. To obtain a topologically optimized configuration, which includes size and shape optimization, thickness of the active damping layer is interpolated using linear functions. With the control energy as the objective function to be minimized, the state error energy is introduced as the dynamic performance criterion for the system and used lot a constraint. The optimal control gains are evaluated from LQR simultaneously as the optimization of the layer position proceeds. From numerical simulation, the topologically optimized distribution of the active damping layer shows the same dynamic performance and cost as the Idly covered counterpart, which is optimized only in terms of control gains, with less amount of the layer.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.19-30
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• 2015

The objective of this study is to analyze the performance and farmer's awareness on the large-scale environment-friendly agricultural districts (LEAD). For this, we survey 393 farmers who cultivate in the 14 LEAD. Most of farmers aware a necessity of LEAD project. They have a higher awareness and practical use on the 'production facilities and equipments for environment-friendly agricultural materials' and 'resource recovery center of crop-animal farming'. The spread and consciousness on the environment-friendly agriculture increase before LEAD project. Also the environment-friendly agricultural areas and incomes slightly increase. The results of this study show that the LEAD project need a modification in to response to change of agricultural issues and customer's needs.

• Research in Mathematical Education
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• v.13 no.3
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• pp.181-195
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• 2009

Students' approaches to mathematical problem solving vary greatly with each other. The main objective of the current study was to compare students' performance with different thinking styles (divergent vs. convergent) and working memory capacity upon mathematical problem solving. A sample of 150 high school girls, ages 15 to 16, was studied based on Hudson's test and Digit Span Backwards test as well as a math exam. The results indicated that the effect of thinking styles and working memory on students' performance in problem solving was significant. Moreover, students with divergent thinking style and high working memory capacity showed higher performance than ones with convergent thinking style. The implications of these results on math teaching and problem solving emphasizes that cognitive predictor variable (Convergent/Divergent) and working memory, in particular could be challenging and a rather distinctive factor for students.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.1
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• pp.30-38
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• 2013

This paper describes the design optimization of Unmanned Aerial Vehicles(UAVs). An optimization framework has been developed and implemented for the conceptual design of UAVs. An integrated design analysis program was developed with several analysis modules such as propulsion, performance, mission, weight, and stability and control. A UAV configuration design optimization was performed by implementing the integrated analysis to enhance the endurance of UAVs. A SQP optimizer was utilized to build an optimization module for this program and sensitivity analysis was performed to determine the trends of shape variables for developing optimization objective. In conclusion, the results indicate that the resulting optimized UAVs configurations show performance improvements over the baseline design and reliable analysis results.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.351-357
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• 2003

In absorption system, the performance of the absorber is critical the overall system performance, size, and first-cost. The objective of this paper is to provide a comprehensive review of the significant effects that researchers have made to numerically analysis model the coupled heat and mass transfer process that occur during falling-film absorption and experimental researches. This study includes experimental work in the enhancement of absorption performance, the effect of the geometry of a vertical absorber, and the effect of configuration of absorption system. This paper is used to highlight key areas which need attention such as film ans vapor hydrodynamics, especially the non-periodicity, instability, and recirculatory motion of waves in the vertical absorber case.

• Journal of Information Technology Services
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• v.7 no.2
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• pp.25-39
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• 2008

As the amount of IT investment and the complexity of information systems in public agencies have been increased, efficient and structured management of IT systems is more emphasized. For the Korean government. ITA (Information Technology Architecture) is one of the core parts of the e-Government initiative. Also introducing and managing ITA in organizations is mandated by law in Korea. The objective of the paper is to study whether using ITA in public agencies is related with their IT capability and IT performance or not. A questionnaire had been designed for the purpose, and a survey had been performed on Korean public agencies. The survey results show that using ITA has influence on relation and technology capability. However, ITA does not influence on human capability and IT performance. The reason why using ITA is linked to relation and technology capability is that ITA includes relationship between both business and technology. Also ITA provides a technical reference model (TRM) and standard profile (SP), so it has influence on technology capability.

• Journal of Information Technology Services
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• v.7 no.2
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• pp.95-111
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• 2008

The objective of this study is to suggest the effects of the fit between project managers' competency and leadership style on the performance of IT projects. Also, this study examine that the project duration among the project's characteristics moderates the impact of the managers' competency and leadership style on the performance of IT projects. As the results of analysis, we found that the participative leadership and the supportive leadership of project manager is affected by the human and the conceptual skills, and the directive-achievement leadership is affected by the technical skills positively. The project duration moderates the impact of the fit between the participative leadership and the technical skills. and the fit between the directive-achievement leadership and the technical and the human skills positively.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.203-205
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• 2001

This paper is part of an ongoing project of KEPCO; 'A Study on Criteria and Standards for Transmission System Planning', The objective of this project is to develop the standards and procedures for transmission system planning. This involves reviewing published literatures, other documents of existing criteria and procedures, and various case studies of advanced countries which are already under the competitive electricity industry. This paper presents the result of evaluating Korean Power System as a pre-study for developing the Planning Standards of Korean Power System. For this, WSCC/NERC's performance criteria for planning transmission system, and KEPCO's 'Long Term Transmission System Planning Criteria' are considered. By doing this, the level of performance criteria which should be applied to Korean Power System and the detailed procedures which would be used in system test were reviewed.

• Journal of Auto-vehicle Safety Association
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• v.7 no.1
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• pp.13-19
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• 2015

Recently, Child safety has become one of the issue with Q10 dummy representing large child. The objective of this paper was to evaluate performance of three child restraints system (backless booster, high-back booster and without booster) by changing D-ring location in the rear seat. Sled tests were carried out with a Q 10 in 64km/h frontal impact. Before the dynamic sled tests, we assessed dummy positioning with difference in CRS types and height adjustment positions. Dynamic sled test results indicated that there is different performance of CRS types and belt routing. These test results will use as base line data for development CRS safety performance for Q 10.

• Journal of the Korea Society of Computer and Information
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• v.20 no.12
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• pp.175-180
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• 2015

It is important to maintain information system (IS) following the business and institutional change. Even if successfully developed information systems, we cannot gain the benefit from the systems without the proactive maintenance activities. However, the importance of IS maintenance has not been considered as much as the system development, and we don't have any specific performance management structure. The objective of this study is to identify the relationship between IS maintenance activities and utilization. For empirical test of the hypothesis model, the sample data is collected from public information system sites. Results from multiple regression analysis reveal that proactive maintenance activities including IS maintenance cost increase, improving functionality, and enhancing ease of use have a causal effect on the IS utilization.