• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.25-40
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• 2015

Understanding the effects of the parameters affecting the interaction of tandem hydrofoil system is a crucial subject in order to fully comprehend the aero/hydrodynamics of any vehicle moving inside a fluid. This study covers a parametric study on tandem hydrofoil interaction in both potential and viscous fluids using iterative Boundary Element Method (BEM) and RANSE. BEM allows a quick estimation of the flow around bodies and may be used for practical purposes to assess the interaction inside the fluid. The produced results are verified by conformal mapping and Finite Volume Method (FVM). RANSE is used for viscous flow conditions to assess the effects of viscosity compared to the inviscid solutions proposed by BEM. Six different parameters are investigated and they are the effects of distance, thickness, angle of attack, chord length, aspect ratio and tapered wings. A generalized 2-D code is developed implementing the iterative procedure and is adapted to generate results. Effects of free surface and cavitation are ignored. It is believed that the present work will provide insight into the parametric interference between hydrofoils inside the fluid.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.124-131
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• 2009

In any form of construction work, it is essential that accidents be prevented at every stage, from foundation preparation to build completion. For this, it is necessary to use models that can assess risk and provide instructions for safe work processes so that the risk of accidents is reduced. Currently, however, very few models can perform these tasks. In this paper, we present a model that assesses risk quantitatively by analyzing the risk factors involved in each stage of construction, such as foundation work, temporary work, structural work, equipment work, and finishing work. The model performs assessment based on examples of accidents and by investigating actual conditions during construction. In addition, we present in this paper a safety management system developed to assess risk during construction and to effectively train laborers.

• Journal of the Korean Geotechnical Society
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• v.15 no.4
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• pp.19-42
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• 1999

In urban area, there are several major factors to be considered in tunnel design and construction. The first is to predict the magnitude and distribution of ground movements for particular ground conditions and construction procedures. The second is to assess the potential damage to nearby structures in response to the predicted ground movements. The third is to select the measures to be taken if a potential damage is foreseen. This study is concerned primarily with the first and second stages of the problem. Particularly, this paper is focused on the second stage to assess the potential damage to the nearby building with any type of geometries and locations above ground surface. In order to solve this problem, we introduced damage parameters(angular distortion, deflection ratio, maximum building settlements, maximum differential settlements, horizontal strain, etc.), and extended these parameters into 3-dimensional safety assessment. Also, to assess the safety of any walls existing in the building, we developed a 3-dimensional analysis program, and various parametric studies for the nearby building with any type of geometries and locations were presented. In addition to these parametric studies, we compared the results of the proposed techniques with some abroad case records for particular tunnels and adjacent buildings.

• Journal of Information Technology Applications and Management
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• v.18 no.4
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• pp.55-79
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• 2011

This study attempts to examine the factors affecting the introduction of e-Business systems and also, to assess the effects of various e-Business systems on firm performance. Empirical analysis is carried out with firm data of 2009, which is collected from Firm Activity Survey of Statistics Korea. Firm performance is measured by four indexes; operating income per employee, value added per employee, return on assets, and return on sales. Empirical results indicate that a firm is more likely to introduce any e-Business system as its size and its assets per employee are larger and as its ratio of labor compensations to operating costs is lower. Additionally, a firm with higher skill levels and more fruitful management experiences is more likely to have any e-Business system. In general, it appears that the presence of e-Business, especially enterprise resources planning, has positive effects on the firm performance.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.35.2-35.2
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• 2013

I will present a new approach to constrain galaxy physical parameters from the combined interpretation of stellar and nebular emission in wide ranges of observations. This approach relies on a comprehensive library of synthetic spectra, assembled using state-of-the-art models of star formation and chemical enrichment histories, stellar population synthesis, nebular emission and attenuation by dust. We focus on the constraints set by 5-band photometry and low- and medium-resolution spectroscopy at optical rest wavelengths on a few physical parameters characterizing the stars and interstellar medium. Since these parameters cannot be known a priori for any galaxy sample, we assess the accuracy to which they can be retrieved by simulating 'pseudo-observations' using models with known parameters. We find that the combined analysis of stellar and nebular emission in low-resolution (50A FWHM) galaxy spectra provides valuable constraints on all physical parameters. The approach can be extended to the analysis of any type of observation and during this talk i will present some applications to observed galaxies up to redshift 1.5.

• Proceedings of the Korean Statistical Society Conference
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• 2003.10a
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• pp.149-154
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• 2003

문항반응이론(item response theory, IRT)에서는 문항이 가지고 있는 특성을 기초로 피험 자의 능력을 추정 하고 동시 에 각 문항별 문항특성곡선(item characteristics curve; ICC)을 이용하여 문항모수를 추정하게 된다. 이러한 추정알고리즘은 이미 외국에서는 상용화되 어 활용되고 있는바, 국내 에서 개 발한 Any Assess의 활용 가능성을 모의 실험을 통하여 그 결과의 신뢰성을 검증해 보았다.

• Communications for Statistical Applications and Methods
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• v.24 no.6
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• pp.583-604
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• 2017

The most popular regression model for the analysis of time-to-event data is the Cox proportional hazards model. While the model specifies a parametric relationship between the hazard function and the predictor variables, there is no specification regarding the form of the baseline hazard function. A critical assumption of the Cox model, however, is the proportional hazards assumption: when the predictor variables do not vary over time, the hazard ratio comparing any two observations is constant with respect to time. Therefore, to perform credible estimation and inference, one must first assess whether the proportional hazards assumption is reasonable. As with other regression techniques, it is also essential to examine whether appropriate functional forms of the predictor variables have been used, and whether there are any outlying or influential observations. This article reviews diagnostic methods for assessing goodness-of-fit for the Cox proportional hazards model. We illustrate these methods with a case-study using available R functions, and provide complete R code for a simulated example as a supplement.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.619-637
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• 2011

The development of society and the desire for a happy life for the safety of the public's interest in higher things of the increased body, Bain safety awareness and safety of repeated disasters without action to prevent the spread will have no choice but to tough it will also harm. Safety education training from an early age desperately needed for safety's why. Elementary Middle High School students' characteristics and level of safety for your knowledge, skills, attitudes and habits in order to train to teach in any manner whatsoever any information about the study will assess the need.

• The Korean Journal of Applied Statistics
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• v.21 no.5
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• pp.889-900
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• 2008

Child labour is a disturbing issue for any society. It is attempted here in this article to develop an estimator to assess the numerical strength of this menace in Lahore division. A Horvitz and Thompson (1952) type of estimator is developed where weights are calculated on the basis of poverty and illiteracy to increase the sampling efficiency. Different characteristic features of this estimator, like its unbiasedness, variance, probability distribution, confidence intervals are also developed for its study from different angles.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.487-497
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• 2008

This paper addresses the Fault Monitoring System developed by Hyundai-Rotem based on the Mil-HDBK-2155 Failure Reporting, Analysis and Corrective Action System. The purpose of a FRACAS is to provide a documented history of any problems, failures, their associated corrective actions as well as detailing how and why each problem arose or failure occurred during the Warranty Period for Rolling Stock delivered by Hyundai-Rotem. The Fault Monitoring System can assess the reliability, availability and maintainability as well as can predict no. of failure at a time which can input to Life Cycle Cost.