• 자원환경지질
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• 제27권1호
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• pp.81-91
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• 1994

There has been considerable research dealing with the influence of surface roughness along surfaces of rock discontinuities in relation to the peak shear strength of rock masses. Concepts accepted recently for measuring such strength include estimation of a roughness coefficient such as developed by Barton's studies. The method for estimation the Joint Roughness Coefficient (JRC) value of a measured roughness profile is subjective. The aim of this research is to estimate the JRC value of the roughness of a surface profile in a rock mass system using an objective method. The study of roughness of surfaces has included measurement of fractal geometric characteristics. Once the irregularity of the surface has been described by the fractal dimension, the spatial variation of the surface irregularities can be described using variogram and drift analysis. An empirical relationships between the roughness profiles of selected JRC ranges and their fractal dimension with variogram and drift were derived. The application of analyses of fractal dimension, variogram and drift was novel for the analysis of roughness profiles. Also, an empirical equation was applied to experimental data.

• 산업경영시스템학회지
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• 제23권54호
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• pp.119-128
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• 2000

This study develops the pay satisfaction questionnaire for Korean employees. Based upon the review of previous studies, 16 questionnaire items are developed. Exploratory factor analysis results in a modified measurement through item deletion, item-to-dimension reassignment, and dimension combination. The measurement model was good fit assessed by overall fit measures(GFI; goodness of fit index, AGFI; adjusted goodness of fit index, RMR; root mean square residual) criteria, lambda score, and squared multiple correlation with confirmatory factor analysis. Implication of this work for future theoretical and empirical development are suggested.

• 한국환경과학회지
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• 제20권1호
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• pp.25-34
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• 2011

The new empirical static model was constructed on the basis of dimension analysis to predict the pressure drop according to the operating conditions. The empirical static model consists of the initial pressure drop term (${\Delta}P_{initial}$) and the dust mass number term($N_{dust}=\frac{{\omega}_0{\nu}_f}{P_{pulse}t}$), and two parameters (dust deposit resistance and exponent of dust mass number) have been estimated from experimental data. The optimum injection distance was identified in the 64 experimental data at the fixed filtration velocity and pulse pressure. The dust deposit resistance ($K_d$), one of the empirical static model parameters got the minimum value at d=0.11m, at which the total pressure drop was minimized. The exponent of dust mass number was interpreted as the elasticity of pressure drop to the dust mass number. The elasticity of the unimodal behavior had also a maximum value at d=0.11m, at which the pressure drop increased most rapidly with the dust mass number. Additionally, the correlation coefficient for the new empirical static model was 0.914.

• Journal of electromagnetic engineering and science
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• 제17권4호
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• pp.241-243
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• 2017

In this paper, we have presented an equation for estimating the gain of a Fabry-Perot cavity (FPC) antenna with a finite dimension. When an FPC antenna has an infinite dimension and its height is half of a wavelength, the maximum gain of that FPC antenna can be obtained theoretically. If the FPC antenna does not have a dimension sufficient for multiple reflections between a partially reflective surface (PRS) and the ground, its gain must be less than that of an FPC antenna that has an infinite dimension. In addition, the gain of an FPC antenna increases as the dimension of a PRS increases and becomes saturated from a specific dimension. The specific dimension where the gain starts to saturate also gets larger as the reflection magnitude of the PRS becomes closer to one. Thus, it would be convenient to have a gain equation when considering the dimension of an FPC antenna in order to estimate the exact gain of the FPC antenna with a specific dimension. A gain versus the dimension of the FPC antenna for various reflection magnitudes of PRS has been simulated, and the modified gain equation is produced through the curve fitting of the full-wave simulation results. The resulting empirical gain equation of an FPC antenna whose PRS dimension is larger than $1.5{\lambda}_0$ has been obtained.

• 기술혁신학회지
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• 제9권1호
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• pp.149-174
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• 2006

기술학습에 대한 개념 연구 및 실증연구가 증가하고 있음에도 불구하고 기업의 구체적인 기술학습과정을 파악하고자 하는 연구는 부족한 실정이다. 본 연구는 기업의 구체적인 기술 지식 학습과정을 분석하기 위하여, 통합적 관점의 기술학습이론에 근거하여 한국의 대표적인 기업이 수행한 13개 기술개발과제에 대한 탐색적 사례연구를 통해 기업의 기술학습과정을 조사하였다. 13개 기술개발과제의 기술학습과정에 대한 사례연구 결과, 두 가지 기술학습과정 유형을 도출할 수 있었다. 첫 번째 기술학습과정 유형은 인지학습과 행동학습의 순서에 따라 네 가지 기술학습과정으로 나누어졌다. 이 기술학습과정 유형은 기술능력 수준에 따라 구분될 수 있었다. 두 번째 기술학습과정 유형은 인지학습과 행동학습의 상대적 난이도에 따라 두 가지 기술학습과정으로 나누어졌다. 이 기술학습과정 유형은 기술의 특성에 따라 구분될 수 있었다. 마지막으로 기술학습을 위한 경영적 함의와 결론, 연구의 한계를 제시하였다.

• 대한간호학회지
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• 제29권3호
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• pp.467-484
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• 1999

The main objectives of this study were to investigate the concept of family function from the perspective of the contemporary Korean family, and to construct model of change of family function with chronic illness. The hybrid model approach was applied in which three phases(theoretical phase, empirical phase, and analytic phase) of concept development were explored for family functioning. The study was conducted from 1997 to 1998. In empirical phase, two groups of purposive samples were drawn : normal family group composed of six families without ill family member, and ill family group composed of seven families of which wives have rheumatoid arthritis. Only families with child(or children) in primary or secondary schools were included in the study. The results were as follows : In theoretical phase, six dimensions of family concept were emerged : affective, structural, control, cognitive, financial, and reproductive dimension. In order to analyse the Korean normal family function in middle class with middle-aged women, financial and reproductive dimension were not included. In empirical phase, five dimensions(affective, structural, control, cognitive, and external relationship) were found from the normal family data. External relationship dimension is very important factor as a resource of the support, especially when their parents or siblings had no help or support to them. In the affective dimension, Korean family emphasized harmony and balance rather than affective expression between couples and between parents and children. They also showed common goals of the families to solve their problems to control the family members. The priority of the goals was getting into the higher education of their children or helping their unhealthy parents or family members. Six dimensions (affective, structural, control, cognitive, external relationship, and financial) of family functions were emerged from the ill family data. From the analysis of ill family data, types of restructuring house chore after wives illness were developed : (a) negociated, (b) accomodated, and (c) isolated, enduring types. Although the dimensions of family functioning identified in this study are similar to the conceptualizations that exist in the western literature, there were distinct differences in the nature of major themes and subconcepts under these family function dimensions.

• Journal of Information Technology Applications and Management
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• 제12권3호
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• pp.81-96
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• 2005

ASP (Application service provider) as a new type of information systems service has been popular recently and has taken a much attention of information systems professionals and researchers. One stream of the research on ASP performed by IS community dealt with utilization and benefits of ASP systems use. The other researchers argue the importance of ASP vendors' capability to provide users with appropriate services. Kern, Lacity and Willcock (2002) summarized the components of core competency of service providers based on their extensive case studies on application service providers. Also, Levina and Ross (2003) developed a value delivery process of application service Providers in their case study This study is developing Prepositions and an empirical model based on the theory of core competency from strategic management study. The dimension of core competency is composed of management competency, technical service competency and customer service competency. Each dimension is made up of competency items derived from previous studies and adapted by professionals in ASP industry. The validity of the dimensions and items in each dimension has been checked with factor analytic method for empirical test. The core competency dimensions are correlated with performance factors of application service providers including growth of revenue, asset and customer base.

• 품질경영학회지
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• 제29권3호
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• pp.151-165
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• 2001

The purpose of this study is to develop systematic methods for evaluating the suitability of a seat and build an empirical model for predicting the suitability of a seat. The following research schemes were pursued to achieve the objectives - Development of suitable chair dimensions - Analysis scheme for decomposing the human-product interface system - Development of model for evaluating suitability. As a result, we uncovered six dominant suitability dimensions for the design of a comfortable seat that is related to the physical dimension of a body, Here, six suitability dimensions were identified as the dimensions that represent the human sensitivity and psychological feeling on comfortable seats. Also, 43 human-interface elements (HIE's) such as seat height, seat width, seat depth, tilting angle, seat surface etc. were investigated. HIE was generally defined as the physical characteristic of manufacturing goods, and it had close related to the body dimension of a user and environment that it was used.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.503-509
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• 2004

With modem computational fluid dynamics method (CFD), air-charging models of the air brake pipe system and auxiliary reservoir are built. Compared with one-dimension model, no empirical formula is introduced to solve branch pipe fields for two-dimension model. A modified operator-splitting method is presented to solve the coupled equations of pressure and velocity, and numerical simulation shows that it is very stable. Compare the numerical results with empirical data of heavy haul trains in home and abroad so as to prove the correctness of the theory and algorithm presented. This paper gives theoretic reference to the experiments of braking effects of heavy haul trains, and forms a basis for development of complete freight train air brake system simulation.

• Journal of the Korean Data Analysis Society
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• 제20권6호
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• pp.2733-2746
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• 2018

The two inverse regression estimation methods, SIR and SAVE to estimate the central space are computationally easy and are widely used. However, SIR and SAVE may have poor performance in finite samples and need strong assumptions (linearity and/or constant covariance conditions) on predictors. The two non-parametric estimation methods, MAVE and dMAVE have much better performance for finite samples than SIR and SAVE. MAVE and dMAVE need no strong requirements on predictors or on the response variable. MAVE is focused on estimating the central mean subspace, but dMAVE is to estimate the central space. This paper explores and compares four methods to explain the dimension reduction. Each algorithm of these four methods is reviewed. Empirical study for simulated data shows that MAVE and dMAVE has relatively better performance than SIR and SAVE, regardless of not only different models but also different distributional assumptions of predictors. However, real data example with the binary response demonstrates that SAVE is better than other methods.