• Journal of information and communication convergence engineering
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• v.5 no.2
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• pp.83-87
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• 2007

This research studies real time interaction and dynamic data shared through 3D scenes in virtual network environments. In a distributed virtual environment of client-server structure, consistency is maintained by the static information exchange; as jerks occur by packet delay when updating messages of dynamic data exchanges are broadcasted disorderly, the network bottleneck is reduced by predicting the movement path by using the Dead-reckoning algorithm. In Dead-reckoning path prediction, the error between the estimated and the actual static values which is over the threshold based on the shared object location requires interpolation and multicasting of the previous location by the ESPDU of DIS. The shared dynamic data of the 3D virtual environment is implementation using the VRML.

• KIEE International Transactions on Power Engineering
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• v.3A no.3
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• pp.161-167
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• 2003

This paper presents a study performed to investigate the steady-state operational strategies of UPFCs in the Jeollanam-Do system in Korea. The objective of the study was to determine the UPFC operating points under normal and contingency conditions. The study consists of developing load flow models to simulate different load levels with and without UPFCs in the system, assessing the effectiveness of UPFCs by contingency analysis, and introducing optimal corrective actions for removing voltage problems caused by contingencies. The paper describes analytical tools, models and approach. It also includes analysis and discussion of the study results. The paper contributes to the area of transmission operational studies with FACTS applications.

• International Journal of Fluid Machinery and Systems
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• v.10 no.2
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• pp.99-118
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• 2017

ECHO progress was defined to depict the rotordynamic pump theory development. Experience (E) era for pumps lasted nearly one and a half hundred years before the Industrial Revolution due to the low rotation speed of motor and undeveloped manufacture ability. Classic (C) theory referring to quasi-static performance as well as the items those were not able to be steadily resolved under the level were briefly and sophisticated outlined. Since 1962, flow instabilities and the dynamic responses had come into main attention with the development of the modern technologies such as ballistic missile, rocket and space shuttle main engine, and were finally heuristically (H) elucidated by talented scholars and researchers. Recently, new applications for the pumps open (O) to the surrounding fluid and diversity of the medium such as multiphase flow need more studies and some examples were briefly introduced to display the potential problems lastly.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.241-247
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• 2009

It is important to satisfy the requirements and standards for the protections of passengers in a car accident. There are lots of studies on the crushing energy absorption of a structure members in automobiles. We have studied to investigate collapse characteristics and moisture absorption movements of CFRP(Carbon Fiber Reinforced Plastics) hat shaped sectional members when CFRP laminates are under the hygrothermal environment. In particular, the absorbed energy, mean collapse load and deformation mode were analyzed for side members which absorbed most of the collision energy. Variation of CFRP interlaminar numbers is important to increase the energy absorption capability. Therefore we have made a static collapse experiment to research into the difference of absorbed energy and deformation mode between moisture absorbed specimen and non-moisture absorbed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.437-446
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• 2013

There have been numerous studies on end milling processes. However, these have been restricted to the application of tools for special cutting purposes. A side milling cutter can handle long, deep, and open slots in a more efficient manner, and it provides the best stability and productivity for this type of milling. In this paper, a method to predict the cutting forces in side milling is described, and simulated cutting forces are compared with those obtained by cutting experiments. In particular, the side milling process easily generates relative motion between the tools and the workpiece because it produces intermittent cutting forces that cause vibrations over a wide frequency range. Therefore, the application of a dynamic cutting model instead of a static cutting model is appropriate to forecast the cutting forces more accurately.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.73-78
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• 2001

It has been proposed that the acceptable level of discomfort was a valid measure of postural loading. Although the number of women employees has increased at a much faster rate than men workers did and female workers are thought to be more vulnerable to musculoskeletal disorders, most previous studies dealt with perceived discomforts for joint motions focused on male subjects. This study aims to measure perceived discomfort ratings of females for static joint motions. Ten female subjects participated in the experiment measuring perceived discomforts, in which almost every possible joint motion was included and the free modulus method of the magnitude estimation was employed. The results showed that discomfort levels were dependent on the joint motions and joints, and subjective discomfort ratings of women were significantly larger than those of men.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.233-236
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• 2001

This study explores on the static and dynamic growth patterns of high-tech ventures in Korea. We developed an integrative framework with target market (local vs. global), product/market maturity (existing vs. emerging), and technological capability (follower vs. pioneer). We also identified seven new ventures strategies as follows: i) reactive imitation, ii) proactive localization, iii) import substitution, iv) creative imitation, v) early market-entry, vi) global niche, and vii) global innovation. With five successful Korean new ventures, we found different competitive behaviors and performance among new venture strategic types. This study also observed two different growth patterns: growth through strategic replication and growth through strategic change. It depends on whether they are pursuing similar strategy over time or different strategy within for growth. In addition, we found that creative imitation plays a stepping-stone role in two-step internationalization processes. Although this study is exploratory and needs more empirical studies, it can provide new ventures with meaningful guidelines for growth and internationalization with a dynamic perspective.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.30-35
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• 2013

Many function of railway signalling system which is in charge of most core function in a railway system are being operated by the software according to the development of computer technology. Accordingly, the source code testing to verify the safety of the railway signalling system software becomes to be more important, and related international standards highly recommend verifications on the source code also. For this reason, several related studies on vital source code verification were executed from several years ago in Korea. This paper performed tests through the application to railway signalling system being applied to the existing actual domestic railway sites through automated testing tools for coding rules of signalling system software and another signaling system software under development in Korea recently, and analyzed their results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.9
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• pp.54-60
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• 2006

Large steel industries have time-varying nonlinear loads such as electric arc furnaces. These nonlinear loads generate harmonic currents and create distortions on the sinusoidal voltage of the power system. The main objective of the static var compensator is to maintain the rms voltage at the point of common coupling within the limit. In this research, harmonic mitigation studies were conducted with and without the SVC, and time-varying harmonics were evaluated according to the international harmonic standards (IEC 61000-3-6 and IEEE Std. 519) using a cumulative probabilistic approach.

• The korean journal of orthodontics
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• v.19 no.2
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• pp.109-120
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• 1989

We tend to consider only static occlusion such as molar relationship, canine key, and interdigitation at finishing stage. Of course, this static occlusion is important for post-orthodontic stability. But we should remember that mandible is always on the move during its various functions. If no pressure or too much pressure is put on during its functions, untoward tooth movement could occur. And tooth mobility, periodontitis, wear facet, bruxism, and far worse temporomandibular disorder could occur. After many studies have been done on what is a desirable occlusal scheme to strengthen post-orthodontic stability, today, "mutually protective occlusion" is recommended. If an orthodontist does not have understanding about this occlusal scheme during orthodontic treatment, the following conditions will be resulted after orthodontic treatment. I. Centric discrepancy 1. centric prematurity 2. sunday bite 3. molar fulcrum II. Eccentric discrepancy 1. posterior interference 2. anterior interference If we have deep understanding about these discrepancies that can happen after orthodontic treatment and their causes, corrections, and especially preventions against them, post-orthodontic stability could be strengthened and further temporomandibular disorder could be prevented.