• ETRI Journal
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• v.30 no.6
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• pp.765-773
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• 2008

Spatial correlation is a result of insufficient antenna spacing among multiple antenna elements, while temporal correlation is caused by Doppler spread. This paper compares the effect of spatial and temporal correlation in order to investigate the performance of multiuser scheduling algorithms in multiple-input multiple-output (MIMO) broadcast channels. This comparison includes the effect on the ergodic capacity, on fairness among users, and on the sum-rate capacity of a multiuser scheduling algorithm utilizing statistical channel state information in spatio-temporally correlated MIMO broadcast channels. Numerical results demonstrate that temporal correlation is more meaningful than spatial correlation in view of the multiuser scheduling algorithm in MIMO broadcast channels. Indeed, the multiuser scheduling algorithm can reduce the effect of the Doppler spread if it exploits the information of temporal correlation appropriately. However, the effect of spatial correlation can be minimized if the antenna spacing is sufficient in rich scattering MIMO channels regardless of the multiuser scheduling algorithm used.

• Human Ecology Research
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• v.58 no.3
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• pp.391-400
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• 2020

This study examined the relationship between ambivalence of Korean working mothers for children and their future desire for child birth. This study examined multiple-role efficacy as a mediator in the relationship between ambivalence for their children and future desire for child birth by Korean working mothers having more than one pre-school aged child. This study examined the mediation effect of multiple-role efficacy on the relationship between ambivalence and desire for child birth by working mothers. On-line and off-line survey data from 291 Korean working mothers with more than one pre-school aged child was used for this study. Collected data were analyzed using the PASW 18.0 program and descriptive statistics analyses. Structural equation modeling and bootstrapping were conducted by AMOS 20.0 program. Results showed that ambivalence for children of working mothers having pre-school aged children had no direct influence on future child birth desire. However, their ambivalence had an indirect influence on future child birth desire through multiple-role efficacy and multiple-role efficacy by working mothers had significant effect on child birth desire. In conclusion, the working mothers' multiple-role efficacy had a mediation influence on the relationship between ambivalence for children and desire of child birth. These results were discussed for designing a policy to counter low birth.

• International Journal of Contents
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• v.3 no.3
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• pp.20-25
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• 2007

Standards impact the economy in various ways. Moreover, intense competition exists between a variety of standards in this era of globalization. This paper quantifies the economic effect of multiple standards in the Information Communications and Technology (ICT) sector. Thus, it identifies and specifies which standard applies when economic gains exist. A model is developed which quantifies the magnitude of the economic effect of multiple standards as compared with a single standard or no standard. The model allows for both the micro- and macroeconomic gains from standardization to be quantified. Preliminary estimates indicate that at the macro level the multiple standards multiplier is approximately three. That is for every dollar invested, the gain is on the order of three dollars. Although not as robust. preliminary results indicated a similar economic gain at the micro level Overall, multiple standards dominate a single standard. This paper applies the model to IMT-2000, an example of multiple standards, to demonstrate this approach to quantify the standards economic effect.

• The Korean Journal of Applied Statistics
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• v.15 no.2
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• pp.269-279
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• 2002

We considered the problem for confirmation of multiple outliers and leverage points. Identification of multiple outliers and leverage points is difficult because of the masking effect and swamping effect. Rousseeuw and van Zomeren(1990) identified multiple outliers and leverage points by using the Least Median of Squares and Minimum Value of Ellipsoids which are high-breakdown robust estimators. But their methods tend to declare too many observations as extremes. Atkinson(1987) suggested a method for confirming of outliers and Fung(1993) pointed out Atkinson method's limitation and proposed another method by using the add-back model. But we analyzed that Fung's method is affected by adjacent effect. In this thesis, we proposed one procedure for confirmation of outliers and leverage points and compared three example with Fung's method.

• Management & Information Systems Review
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• v.32 no.3
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• pp.127-151
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• 2013

This research was to investigate the role of message regulatory focus on the advertising effect of multiple models. The multiple models are limited to two models in one advertisement in this research. This research investigated the hypothesis that multiple models, in terms of multiple source effect and social consensus, appears specifically to enhance the relationship of consumer and commercial models on the conditions of promotion-focused message which leads to the information processing of relational elaboration. This research applied a between-subjects factorial design targeting 2(the number of model: single model vs. multiple models) by 2(message regulatory focus: promotion-focused message vs. prevention-focused message). As a result, multiple models showed more positive ad attitude, brand attitude, and purchase intention than did single model. And promotion-focused message with multiple models showed more positive ad attitude, brand attitude, and purchase intention than did prevention-focused message with multiple models. Also there was an interaction effect between the number of model and the type of message regulatory focus. It wasn't fully supported that there is no difference of advertising effect between promotion-focused message and prevention-focused message on the condition of single model.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.435-441
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• 2012

This paper provides simulation-based results of effect analysis of sample size and sampling periods on accuracy of reliability estimation methods using multiple comparisons with analysis of variance. Sum of squared errors in estimated reliability measures were evaluated through applying seven estimation methods for one-shot systems to simulated quantal-response data. Analysis of variance was implemented to investigate change in these errors according to variations of sample size and sampling periods for each estimation method, and then the effect analysis on accuracy in reliability estimation was performed using multiple comparisons based on sample size and sampling periods. An efficient way to allocate both sample size and sampling periods for reliability estimation tests of one-shot systems is proposed in this paper from the effect analysis results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.12
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• pp.2656-2661
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• 2002

Multiple impact models to examine the effect of stress interference are proposed and investigated. The single shot model analysis, which used various shot ball conditions, was carried out to compare with multiple impacts analysis. Then the multiple impact analysis were performed to predict the effect of the shot ball distances. The results showed that the stress interference in the multiple impact model significantly reduced the maximum value of the compressive residual stresses. The residual stress profiles were strongly effected by the shot ball distances. The multiple impact model can simulate a realistic shot peening process rather than a single shot model does. It is concluded that the proposed model predicts the real process more accurately.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.915-920
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• 2016

A power system designer may have difficulties in choosing a suitable multiple-input converter topology for a specific target application because each multiple-input converter topology presented in the literature has its own advantages and disadvantages. In this perspective, this paper presents a systematic topology selection method for multiple-input converters with three comparison criteria including cost-saving effect, modularity potential and flexibility. Based on these criteria, this paper proposes a strategic flow chart example for choosing a proper multiple-input converter topology. This flow chart will provide a powerful selection tool to a power system designer when he or she chooses a specific multiple-input converter for a given application.

• Journal of Life Science
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• v.20 no.11
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• pp.1611-1616
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• 2010

The purpose of this research was to determine the effect of surfactant micelles on lipid oxidation in W/O/W multiple emulsions. The content of ferric irons and hydroperoxide in the continuous phase in W/O/W multiple emulsions was measured as a function of Brij micelle. The concentration of ferric iron and hydroperoxide in the continuous phase increased with increased storage time (1~6 days). Lipid oxidation rates, as determined by the formation of lipid hydroperoxides, TBARs and headspace hexanal, in the W/O/W multiple emulsions containing ferric iron decreased when 3% surfactant micelles were exceeded. These results indicate that excess surfactant micelles could alter the physical location and prooxidant activity of iron in W/O/W multiple emulsions.

• Knowledge Management Research
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• v.20 no.2
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• pp.1-24
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• 2019

This tutorial introduces procedures and methods for performing structural equation modeling using R. To do this, we present advanced analysis methods based on structural equation model such as mediation effect analysis, moderation effect analysis, moderated mediation effect analysis, and multiple-group analysis with R program code using R lavaan package that supports structural equation modeling. R is flexible and scalable, unlike traditional commercial statistical packages. Therefore, new analytical techniques are likely to be implemented ahead of any other statistical package. From this point of view, R will be a very appropriate choice for applying new analytical techniques or advanced techniques that researchers need. Considering that various studies in the social sciences are applying structural equations modeling techniques and increasing interest in open source R, this tutorial is expected to be useful for researchers who are looking for alternatives to existing commercial statistical packages.