• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 1999년도 압출 및 인발 심포지엄
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• pp.5-8
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• 1999

The present work is concerned with three-dimensional finite element analysis of the hollow section extrusion process using a porthole die. For economic computation, mismatching refinement, an efficient domain decomposition method with different mesh density for each subdomain, is implemented. The proposed method improves the computational efficiency significantly, especially fur the three-dimensional analysis of extrusion problems. As a numerical example, extrusion of the underframe part of a railroad vehicle are analyzed. For three-dimensional mesh generation of a complicated shape with hexahedral elements, a modified grid-based approach with the surface element layer is utilized. The analysis results are then successfully reflected on the industrial porthole die design.

• Journal of Navigation and Port Research
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• 제37권3호
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• pp.231-237
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• 2013

What to analyze cognitive works that are involved in ship navigation is a basic work to make alternatives for maritime safety such as development of bridge equipments, extraction of potential human errors and development of education/ training methods. In the domains in which much research on the human error has been performed such as aviation and nuclear plant, analysis methods for cognitive work analysis have been developed and applied to them. However, the research on the cognitive work analysis is not sufficient in the maritime domain. This paper proposes a method to analyze cognitive work of ship navigation. The method was developed so that some maritime characteristics and a variety of factors influencing cognitive works are reflected on cognitive work analysis processes. On the other hand, an ship collision accident was analyzed by the proposed method as a case study.

• Convergence Security Journal
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• 제17권3호
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• pp.51-57
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• 2017

VOD service provides an additional revenue for broadcasting companies in addition to the existing subscription fees and advertisement-based revenue. Therefore, each broadcasting company develops its own VOD service and performs frequent improvement work. This leads to the development of new VOD services, so developers are considering ways to effectively handle the frequent development needs. In this background, we conducted an underlying research to apply the feature-oriented analysis model to the development of VOD service. The feature-oriented analysis model used in this study is the Feature-Oriented Domain Analysis (FODA) developed by SEI of Carnegie Mellon University. FODA provides a tool for specifying a feature model of a software domain, based on which developers determine the configuration of a software with customers. This study developed a feature model of the VOD service domain and devised the functionalities and testcases in an integrated manner with the feature model. Additionally, we proposed a VOD service development process utilizing the feature model, function specification, and testcases.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제34권1호
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• pp.25-32
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• 2011

Under limited resources such as budgets and experts, it is essential to set promotion priorities for standardization work items on IPv6 (Internet Protocol version 6) multi-networking technologies. Opinions of domain experts are surveyed and analyzed utilizing a multi-criteria decision making tool, the Analytic Hierarchy Process (AHP). Weights of ten evaluation criteria are identified and applied to calculating importance degree of eight work items. According to descending order of importance degree, priorities of work items are determined. The processes and results of this study may provide not only an approach of setting promotion priorities for standardization work items but also a practical guide of implementing of a multi-criteria decision analysis.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.608-609
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• 2011

In this study, we tried to validate FLUENT solver model and domain setting for the problem of convective heat transfer in multiple tube bank under transitional zone. We have paid special attention to verify proper boundary conditions and the grid convergence. Through validation work, it is found that unsteady solution method with two-dimensional simulation domain can produce reasonable accurate results compared with existing experimental data. Simulation results with steady solution generates relatively large error. We found that both steady and unsteady method for three-dimensional domain shows acceptable accuracy. Further parametric study for deriving correlation from transverse and longitudinal pitch is currently underway.

• Journal of the Korea Institute of Military Science and Technology
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• 제25권4호
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• pp.339-346
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• 2022

The importance of stealth technology is increasing in modern warfare, and Radar Cross Section(RCS) is widely used as an indicator of stealth technology. It is useful to measure RCS using an image-based near-field to far-field transformation algorithm in short-range monostatic conditions. However, the near-field measurement system requires a longer measurement time compared to other methods. In this work, it is proposed to reduce the measured data using an interpolation method in azimuth angular domain. The calculated far-field RCS values according to the sampling rate is shown, and the performance of the algorithm applied with interpolation in the angular domain is presented. It is shown that measurement samples can be reduced several times by using the redundancy in the angular domain while producing results similar to the conventional method.

• Journal of the Korean Magnetic Resonance Society
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• 제17권1호
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• pp.59-66
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• 2013

BldD, a developmental transcription factor from Streptomyces coelicolor, is a homodimeric, DNA-binding protein with 167 amino acids in each subunit. Each monomer consists of two structurally distinct domains, the N-terminal domain (BldD-NTD) responsible for DNA-binding and dimerization and the C-terminal domain (BldD-CTD). In contrast to the BldD-NTD, of which crystal structure has been solved, the BldD-CTD has been characterized neither in structure nor in function. Thus, in terms of structural genomics, structural study of the BldD-CTD has been conducted in solution, and in the present work, mainchain NMR assignments of the recombinant BldD-CTD (residues 80-167 of BldD) could be achieved by a series of heteronuclear multidimensional NMR experiments on a [$^{13}C/^{15}N$]-enriched protein sample. Finally, the secondary structure prediction by CSI and TALOS+ analysis using the assigned chemical shifts data identified a ${\beta}-{\alpha}-{\alpha}-{\beta}-{\alpha}-{\alpha}-{\alpha}$ topology of the domain. The results will provide the most fundamental data for more detailed approach to the atomic structure of the BldD-CTD, which would be essential for entire understanding of the molecular function of BldD.

• Journal of the Korean Society of Manufacturing Process Engineers
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• 제15권6호
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• pp.16-23
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• 2016

This study was carried out to investigate how grade level and experiences when taking courses affect the creativity of engineering students in a Korean college. The sample group consisted of 372 engineering students of which 49.5% were first graders, 15.6% second graders, 22.6% third graders, and 12.4% fourth graders. They conducted self-report measures on a domain-general and domain-specific view of creativity. The engineering creativity test, developed by Kang and Yune (2015), is based on the domain-specific view of creativity and consists of four sub-factors: creative attitude, knowledge research, interest in engineering, and team work ability. The domain-general creativity test consists of three sub-factors. Analysis of the results led to the following conclusions: First, we found significant differences in engineering creativity between students depending on experiences in taking courses and tests; and, second, we discovered significant differences in integrative creativity among students depending on experiences in taking courses and tests, and/or grade level. These conclusions suggest that we should develop and apply appropriate strategies to enhance creativity in engineering education.

• Journal of Power Electronics
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• 제11권4호
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• pp.439-448
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• 2011

In this work the Multi-Domain model of an electric vehicle is developed. The electric domain model consists on the traction drive and allows including faults associated with stator winding. The thermal model is based on a spatial discretization. It receives the power dissipated in the electric domain, it interacts with the environment and provides the temperature distribution in the induction motor. The mechanical model is a half vehicle model. Given that all models are obtained using the same approach (Bond Graph) their integration becomes straightforward. This complete model allows simulating the whole system dynamics and the analysis of electrical/mechanical/thermal interaction. First, experimental results are aimed to validate the proposed model. Then, simulation results illustrate the interaction between the different domains and highlight the capability of including faults.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.175-183
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• 2016

This paper brings out a novel method for reducing Near end and Far end Crosstalk using Electromagnetic Band Gap structures (EBG) in High Speed RF transmission lines. This work becomes useful in high speed closely spaced Printed Circuit Board (PCB) traces connected to multi core processors. By using this method, reduction of −40dB in Near-End Crosstalk (NEXT) and −60 dB in Far End Crosstalk (FEXT) is achieved. The results are validated through experimental measurements. Time domain analysis is performed to validate the signal integrity property of coupled transmission lines.