• Title/Summary/Keyword: Empirical power

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A Study on Factor Analytical Methods and Procedures for PLS-SEM (Partial Least Squares Structural Equation Modeling)

  • YIM, Myung-Seong
    • The Journal of Industrial Distribution & Business
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    • v.10 no.5
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    • pp.7-20
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    • 2019
  • Purpose - This study provides appropriate procedures for EFA to help researchers conduct empirical studies by using PLS-SEM. Research design, data, and methodology - This study addresses the absolute and relative sample size criteria, sampling adequacy, factor extraction models, factor rotation methods, the criterion for the number of factors to retain, interpretation of results, and reporting information. Results - The factor analysis procedure for PLS-SEM consists of the following five stages. First, it is important to look at whether both the Bartlett test of sphericity and the KMO MSA meet the qualitative criteria. Second, PAF is a better choice of methodology. Third, an oblique technique is a suitable method for PLS-SEM. Fourth, a combined approach is strongly recommended to factor retention. PA should be used at the onset. Next, it is recommended using the K1 criterion. In addition, it is necessary to extract factors that increase the total variance explanatory power through the PVA-FS. Finally, it is appropriate to select an item with a factor loading into 0.5 or higher and a communality of 0.5. Conclusions - It is expected that the accurate factor analysis processed for PLS-SEM as previously presented will help us extract more precise factors of the structural model.

A Scheduling System based on DBMS for Shipbuilding (DATABASE 기반의 조선업 일정계획 시스템 구축)

  • Lee, Dong-Uk;Kim, Shun-Kyum;Lee, Ho-Yoon;Park, Sung-Kyu;Lee, Dae-Hyeong;Wang, Gi-Nam
    • Korean Journal of Computational Design and Engineering
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    • v.17 no.1
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    • pp.26-34
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    • 2012
  • Assembly scheduling in shipbuilding is responsible for determine assembly process orders and departmental production schedule for the block, the basic composite unit of ships. It is necessary much more information to decide production scheduling as the characteristic of shipbuilding which has been more complex and more various and also, a lot of waste of time and of human power is generated in the course of data processing. The target shipbuilding manufacturer of this study use empirical techniques, based on the user's discretion, to compile and to apply data which are scattered in DB storages separately. Because of that reason, the user should not only be performed identification and screening operations but also modification and verification for vast amounts of data, so it is hard to keep the consistency of the data and also the operation time is not constant. Accordingly, the object in this study is by presenting an efficient DB framework to reduce wasting time and man-hour at experienced-oriented process, abate user's manual operations and support an efficient scheduling in assembly processes.

Design of a Turbine System for Liquid Rocket Engine (액체로켓용 터빈시스템 설계)

  • Choi, Chang-Ho;Kim, Jin-Han;Yang, Soo-Seok;Lee, Dae-Sung;Woo, Yoo-Cheol
    • 유체기계공업학회:학술대회논문집
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    • 2000.12a
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    • pp.145-152
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    • 2000
  • A turbopump system composed of two pumps and one turbine is considered. The turbine composed of a nozzle and a rotor is used to drive the pumps while gas passes through the nozzle, potential energy is converted to kinematic energy, which forces the rotor blades to spin. In this study, an aerodynamic design of turbine system is investigated using compressible fluid dynamic theories with some pre-determined design requirements (i.e., pressure ratio, rotational speed, required power etc.) obtained from liquid rocket engine (L.R.E.) system design. For simplicity of turbine system, impulse-type rotor blades for open type L.R.E. have been chosen. Usually, the open-type turbine system requires low mass flow rate compared to close-type system. In this study, a partial admission nozzle Is adopted to maximize the efficiency of the open-type turbine system. A design methodology of turbine system has been introduced. Especially, partial admission nozzle has been designed by means of simple empirical correlations between efficiency and configuration of the nozzle. Finally, a turbine system design for a 10 ton thrust level of L.R.E is presented.

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Comparative analysis of live satisfaction of husband and wife -Concentrated on subject evaluation of economic level- (부부의 생활 만족도 비교 분석 : 주관적 경제수준 평가를 중심으로)

  • 박미금
    • Journal of the Korean Home Economics Association
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    • v.32 no.1
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    • pp.1-18
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    • 1994
  • The purpose of this study is to find the differences between the husband's and wife's satisfaction of home life. This study is also to compare and analyze some empirical influence on life satisfaction of husband and wife according to home socio-demographic variables and subjective evaluation of economic level including their perception levels of home economics circumstance. The major results are as follows; 1. The husband's score of life satisfaction shows signifcantly more than wife's score that is his score is 3.36 and her score is 3.19. 2. The variables which affect couple's life satisfaction are the perception of resource adequacy the perception of the adequacy of household income, the evaluation level of resource contribution and the perception of level of living relative to others. The most influential variable of the husband is the perception of resource adequacy, while the most influential variable of the sife is the evaluation level of resource contribution. 3. The result of the relative contribution for the variables of life satisfaction are as follows. The explanation of husband's sociodemographic variable is 11.5% if variable of subjective evaluation of economic level is added the explain power is 34.1%(increase, 22.6% (p<0.001)) The explanation of wife's socio-demographic variable is 9.8% If variable of subjective evaluation of economic level is added the explanation is 41.2% (increase 31.4% (p<0.001)).

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Disk-averaged Spectra Simulation of Earth-like Exoplanets with Ray-tracing Method

  • Ryu, Dong-Ok;Kim, Sug-Whan
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.76.2-76.2
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    • 2012
  • The understanding spectral characterization of possible earth-like extra solar planets has generated wide interested in astronomy and space science. The technical central issue in observation of exoplanet is deconvolution of the temporally and disk-averaged spectra of the exoplanets. The earth model based on atmospheric radiative transfer method has been studied in recent years for solutions of characterization of earthlike exoplanet. In this study, we report on the current progress of the new method of 3D earth model as a habitable exoplanet. The computational model has 3 components 1) the sun model, 2) an integrated earth BRDF (Bi-directional Reflectance Distribution Function) model (Atmosphere, Land and Ocean) and 3) instrument model combined in ray tracing computation. The ray characteristics such as radiative power and direction are altered as they experience reflection, refraction, transmission, absorption and scattering from encountering with each all of optical surfaces. The Land BRDF characteristics are defined by the semi-empirical "parametric-kernel-method" from POLDER missions from CNES. The ocean BRDF is defined for sea-ice cap structure and for the sea water optical model, considering sun-glint scattering. The input cloud-free atmosphere model consists of 1 layers with vertical profiles of absorption and aerosol scattering combined Rayleigh scattering and its input characteristics using the NEWS product in NASA data and spectral SMARTS from NREL and 6SV from Vermote E. The trial simulation runs result in phase dependent disk-averaged spectra and light-curves of a virtual exoplanet using 3D earth model.

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A Numerical Study On Various Energy and Environmental Systems (에너지${\cdot}$환경 제반 시스템에 관한 수치해석적 연구)

  • Jang D.S.;Song W.Y.;Na H.R.;Park B.S.;Lee E.J.;Kim B.S.
    • 한국전산유체공학회:학술대회논문집
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    • 1995.10a
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    • pp.160-168
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    • 1995
  • This paper describes computational efforts on the various energy and environmental problems using Patankar's SIMPLE method. The specific problems included in this study are : pollutant and flammable material dispersions in open and confined areas, aerator-induced flow in a lake for DO(dissolved oxygen) concentration, primary clarifier for water and waste water treatment, hood ventilation in workplace, cyclone and LNG combustors and Dow chlorination reactor. A control-volume based finite-difference method is employed together with the power-law scheme. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, says SIMPLER and SIMPLEC. The Reynolds stresses are closed using the standard or the RNG $k-{\varepsilon}$ models. Turbulent reaction is modeled using two fast chemistry methods such as eddy breakup and conserved scalar models. Further, a nonequilibrium model is developed for the application of the chlorination process in the Dow reactor. Other important empirical models and physical insights appeared in this study are presented and discussed in a brief note. The computational method developed in this study is considered, in general, as a viable tool for the design and determination of the optimal condition of various engineering system of interest.

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A study on effect related to health industry through WTO entrance of China (중국(中國) WTO 가입(加入) 및 관세인하(關稅引下)에 따른 4개 분야(分野) 보건산업(保健産業) 수출(輸出)에 대한 연구(硏究))

  • Kim, Jong-Kwon
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.27
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    • pp.165-181
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    • 2005
  • The health industry of China is faster than before, so it will be rank 5th at world-wide markets in 2010. Firstly, the custom tariff was lower at 15% in 2000 and at 10.4% on June 2005. And, it will be lower into 9.8% in 2010. Secondly, this is because of expansion of purchase power on increase in economic growth, extended human life expectancy. As it is entered the WTO in January 2002, it will positively affect on export of Korea for China. This paper focuses on the analysis of export increase caused by reduction of custom tariff in China. As above mentioned, the time schedule on average reduction of custom tariff was 15% in 2000, 10.4% in 2005. Then, it will be lower into 9.8% in 2010. As the empirical test related health industry, it presents 19.80% export increase rate for China of Korea on reduction of custom tariff from 2001 to 2010. The exporting of drug for China will be up to 17.85% for 10 years. Also, the exporting of Biomedical will be up to 20.99%, and respectively 22.95%, 22.60% in Cosmetics and food industry. Conclusionally, the exporting of this health industry will be increase greatly, compared with any other industries. So, it is necessary that firms increase in R&D investment and government support as policy for health industry.

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A Numerical Study On Various Energy and Environmental Systems(Ⅰ) : LPG dispersion, Lake flow, Primary clarifier, Hood ventilation, Cyclone combustor, Dow chlorination reactor. (에너지$\cdot$환경 제반 시스템에 관한 수치 해석적 연구 (Ⅰ) : LPG 확산, 호소 유동, 일차침전조, 국소 환기용 후두, 싸이클론 연소로, Dow 화학 반응로)

  • Jang Dong-Sun;Kim Gyeong-Mi;Lee Eun-Ju;Park Byeong-Su;Kim Bok-Sun
    • Journal of computational fluids engineering
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    • v.2 no.1
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    • pp.93-108
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    • 1997
  • This paper describes several computational results on the various energy and environmental problems using Patankar's SIMPLE method. The specific problems included in this study are : pollutant and flammable material dispersions in open and confined areas, buoyancy-driven flow in a lake, primary clarifier for water and waste water treatment, hood ventilation in workplace. cyclone combustor and Dow chlorination reactor. A control-volume based finite-difference method is employed together with the power-law scheme. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, says SIMPLER and SIMPLEC. The Reynolds stresses are closed using the standard or RNG κ-ε models. A nonequilibrium turbulent reaction model is developed for the application of the chlorination process in the Dow thermal reactor. Other important empirical models and physical insights appeared in this study are presented and discussed in a brief note. The computational method developed in this study is considered, in general, as a viable tool for the design and determination of the optimal operating condition of various environmental engineering system of interest.

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Dynamic behaviour of high-sided road vehicles subject to a sudden crosswind gust

  • Xu, Y.L.;Guo, W.H.
    • Wind and Structures
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    • v.6 no.5
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    • pp.325-346
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    • 2003
  • High-sided road vehicles are susceptible to a sharp-edged crosswind gust, which may cause vehicle accidents such as overturning, excessive sideslip, or exaggerated rotation. This paper thus investigates the dynamic behaviour and possible accidents of high-sided road vehicles entering a sharp-edged crosswind gust with road surface roughness and vehicle suspension included. The high-sided road vehicle is modelled as a combination of several rigid bodies connected by a series of springs and dampers in both vertical and lateral directions. The random roughness of road surface is generated from power spectral density functions for various road conditions. The empirical formulae derived from wind tunnel test results are employed to determine aerodynamic forces and moments acting on the vehicle. After the governing equations of motion are established, an extensive computation work is performed to examine the effects of road surface roughness and vehicle suspension on the dynamic behaviour and vehicle accidents. It is demonstrated that for the high-sided road vehicle and wind forces specified in the computation, the accident vehicle speed of the road vehicle running on the road of average condition is relatively smaller than that running on the road of very good condition for a given crosswind gust. The vehicle suspension system should be taken into consideration, and the accident vehicle speed becomes smaller if the vehicle suspension system has softer springs and lighter dampers.

The Effect of Fit between IT Strategy and IT Investment on the IT Performance (정보기술전략과 투자방향의 일치가 정보기술성과에 미치는 영향)

  • Kang Tea-Gyung
    • Management & Information Systems Review
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    • v.13
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    • pp.27-47
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    • 2003
  • The strategic usages of IT(Information Technology) can convey important competitive advantages with an operational productivity. For this reason, many firms have heavily invested in IT and computing power. However, many companies were getting expected results by IT investment, but some companies had to be satisfied with a poor results. The question of whether or not benefit lead to expected performance is not easy to answer. The purpose of this study was to investigate the relationship among IT strategy, IT investment, and IT performance to resolve this problem. The 147 questionnaire responses completed by IS managers in manufacturing sector was conducted for a test of research hypothesis. ANOVA was used to investigate the relationship among three constructs and six factors. An operational performince of fitted group between IT strategy and IT investment was higher than not fitted group(H1). And also an competitive performance of fitted group between IT strategy and IT investment was higher than not fitted group(H2). The study shows a positive relationship between IT strategic orientation, IT investment direction, and performance of IT. The research results provide empirical evidence that supports the research hypothesis that closer fit between IT strategies and IT investment directions does lead to increase operational and competitive performance of IT.

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