• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.132-137
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• 2000

Recently, a severe noise problem was encountered during a shop test of large scale vertical motor. In order to identify the noise characteristics and propose the countermeasure, a variety of experiments such as sound excitation test and contribution analysis was earned out in addition to ordinary noise and vibration measurements. The results showed that the severe noise level was dominated by an acoustic resonance phenonmenon in the cooler housing and higher sound power of outer fan. Through proper treatments, the noise level could be acceptable.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1179-1182
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• 2007

도시 내에 설치된 카메라를 통해서 각종 영상 정보를 수집해야 하는 경우, 수집된 정보들은 그 양이 방대(Large Scale)하고 복잡하므로 이를 효과적으로 저장하고 전달하기 위해서는 분산된 환경의 카메라 네트워크 시스템에 대한 연구가 필요하다. 본 논문에서는 도시 내에 분산된 카메라 네트워크를 효율적으로 관리하고, 수집된 정보를 필요로 하는 모듈 서버에게 효과적으로 분배하는 SVC를 이용한 시스템에 대한 설계를 제시하고 그 기반 연구를 진행한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.2
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• pp.141-147
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• 2011

This study analyzed the issues and its usefulness of drawing small-scale digital map by using the large-scale digital map which was producted with high-resolution digital aerial photograph which are commonly photographed in recent years. To this end, correlation analysis of the feature categories on the digital map was conducted, and this map was processed by inputting data, organizing, deleting, editing, and supervising feature categories according to the generalization process. As a result, 18 unnecessary feature codes were deleted, and the accuracy of 1/5,000 for the digital map was met. Although the size of the data and the number of feature categories increased, this was proven to be shown due to the excellent description of the digital aerial photograph. Accordingly, it was shown that drawing a small-scale digital map with the large-scale digital map by digital aerial photograph provided excellent description and high-quality information for digital map.

• The Journal of Small Business Innovation
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• v.20 no.2
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• pp.35-50
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• 2017

The aims of this study is to analyze the effectiveness of firms financial status quo and the scale of financial support on SMEs overall performance. We have gathered the financial guarantee data from 1998 to 2013, provided by Korea Credit Guarantee Fund (KODIT), to analyze the effectiveness of Financial policy. To classify both financial status quo and scale of financial support, we utilized the following variables; Interest Coverage Ratio (ICR) and newly guaranteed amount ratio. To take the measurement of the overall performance, we employed profitability, growth ratio and activity index. To minimize the effect of repeated financial support (redundancy benefits), firms were selected based on the following criteria: firms that receive no financial support prior to implementing such policy over the last 3 years and no new financial support over the last 2 years. Results suggest that firms with higher ICR and large newly guaranteed amount influence on financial performance in terms of profitability index. Firms with lower ICR and large scale financial support showed a better performance compare to firms with small-scale financial support. Firms with large-scale financial support, irrespective of ICR inclined to have better performance to those of small-scale financial support in terms of growth index. For activity index, however, firms with large scale support led to higher performance in the short term. In turn, our analysis presents objective perspective with respect to the effectiveness of financial policy through credit guarantee on overall performance of SMEs. This study, therefore, implies that well-balanced SMEs supporting policy may lead to better directions.

• Journal of the Korean Society for Railway
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• v.17 no.1
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• pp.43-51
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• 2014

In the earth structures of railways, large coarse granular materials are widely used as fill materials. However, experimental studies that consider the dynamic properties of these coarse granular materials have rarely been carried out in Korea due to the lack of a large scale test apparatus in this country. In this study, large scale cyclic triaxial tests were carried out for materials such as reinforced roadbed (subballast, graded crushed stone), transition zone gravel, and the upper subgrade of a railway. These specimens were prepared according to certain conditions (dry unit weight, grain size distribution, and so on) specified in the Korea railroad design standard. Based on these large triaxial test results, normalized shear modulus and damping ratio curves according to small strain level are suggested. A model and coefficients for each material are also proposed.

• Journal of Korean Association for Spatial Structures
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• v.10 no.2
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• pp.135-145
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• 2010

The objective of this study is to draw basic data for the application of the fire protection planning for the future plan large enclosure buildings in Korea through an analysis of its characteristics by case studies of the domestic and foreign large scale gymnasiums. In this study, domestic building codes for the fire protection are investigated and fire detection systems, fire extinguishing systems, smoke control systems and evacuation systems of three large scale gymnasiums located at Korea and eight foreign countries are compared and analyzed. The results of this study show that infrared light fire detection system and flame detector for spacial characteristics are potentially used in fire protection systems of large scale gymnasiums: dry type sprinkler and sprinkler water gun are adopted in fire detection system; and smoke accumulation system is widely utilized in smoke control system.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1604-1615
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• 2023

In an open-pool type research reactor with a downward forced flow in the core, pipes can be under sub-atmospheric pressure because of the large pressure drop at the reactor core in the atmospheric pool. Sub-atmospheric pressure can result in air inflow into the pipe from the pressure difference between the atmosphere and the inside of the pipe, which in a postulated pipe break scenario can lead to the breakdown of the cooling pump. In this study, a plant-scale experiment was conducted to study air inflow in large piping systems by considering the actual operational conditions of an advanced research reactor. The air inflow rate was measured, and the entrained air was visualized to investigate the behavior of air inflow and flow regime depending on the pipe break size. In addition, the developed drift-flux model for a large vertical pipe with a diameter of 600 mm was compared with other correlations. The flow regime transition in a large vertical pipe under downward flow was also studied using the newly developed drift-flux model. Consequently, the characteristics of two-phase flow in a large vertical pipe were found to differ from those in small vertical pipes where liquid recirculation was not dominant.

• KIEE International Transactions on Power Engineering
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• v.11A no.4
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• pp.33-38
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• 2001

The KEPS(KEPCO＇s Enhanced Power system Simulator) Real Time Digital Simulator(RTDS) is the largest real time power system simulator ever built. A power system which includes 320 (3-phase) buses and 90 generators has been modeled and run in real time. Since such large-scale systems were involved, it was not practical to validate them using non-real time electro-magnetic transient programs such as EMTDC™ or EMTP. Instead, the results of the real time electromagnetic transient simulation were validated by comparing to transient stability simulations run using PTI's PSS/E™ program. The comparison of results from the two programs is very good in almost all cases. However, as expected, some differences did exist and were investigated. The differences in the results were primarily traced to the fact that the electromagnetic transient solution algorithm provides more detail solutions and therefore greater accuracy than the transient stability algorithm. After finding very good comparison of results between RTDS Simulator and PSS/E, and after investigating the discrepancies found, KEPCO gained the necessary confidence to use the large-scale real time simulator to analyze and develop their power system.

• Journal of the Korean GEO-environmental Society
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• v.13 no.2
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• pp.49-57
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• 2012

Large-scale collapse happened under excavation construction in the past. But, recently the trend that it is completed safely to minimize damages is growing because of increasing levels of design review and detecting signs of problems before the outbreak of large-scale collapse with proactive planning of measurement. In this paper, through studying case collapses over the past, it put the cause of the collapse in order. And then, after reviewing general information on management and utilization of measurement methods which importantly emerging recently, the type and cause of the problem during the excavation was reviewed. And the causes of problem were analyzed by targeting the site which unusual symptoms happened on measuring results under construction. In this study, the awareness that measurement management and subsurface investigation is highly important will increase for preventing large-scale collapse in advance.

• Journal of KIISE
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• v.43 no.5
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• pp.553-561
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• 2016

Several machine learning techniques are able to automatically populate ontology data from web sources. Also the interest for large scale ontology reasoning is increasing. However, there is a problem leading to the speculative result to imply uncertainties. Hence, there is a need to consider the reliability problems of various data obtained from the web. Currently, large scale ontology reasoning methods based on the trust value is required because the inference-based reliability of quantitative ontology is insufficient. In this study, we proposed a large scale OWL Horst reasoning method based on a confidence value using spark, a distributed in-memory framework. It describes a method for integrating the confidence value of duplicated data. In addition, it explains a distributed parallel heuristic algorithm to solve the problem of degrading the performance of the inference. In order to evaluate the performance of reasoning methods based on the confidence value, the experiment was conducted using LUBM3000. The experiment results showed that our approach could perform reasoning twice faster than existing reasoning systems like WebPIE.