• ETRI Journal
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• 제30권6호
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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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• 제58권3호
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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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• 제3권3호
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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.

• 응용통계연구
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• 제15권2호
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• pp.269-279
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• 2002

다중 이상점 과 다중 지렛점의 식별은 가장효과(masking effect)와 편승효과(swamping effect)에 영향을 받으므로 어려움이 존재한다. Rousseeuw와 van Zomeren(1990)은 LMS (Least Median of Squares) 회귀방법과 MVE(Minimum Volume Ellipsoid) 통계량을 이용하여 다중 이상점과 다중 지렛점을 식별하였다. 그러나 이들의 방법은 LMS와 MVE의 강한 로버스트성으로 인하여 이상점과 지렛점이 아닌 점들도 이상점과 지렛점으로 식별하는 경향이 있다. Fung(1993)은 식별된 이상점과 지렛점들에 대하여 재확인방법을 제안하였는데 이 방법은 인근효과(adjacent effect)에 영향을 받아 이상점과 지렛점을 식별하는데 문제가 있는 것으로 분석되었다. 본 논문은 이러한 문제점을 지적하고 새로운 방법을 제안하여 식별된 이상점과 지렛점을 재확인하고자 한다.

• 경영과정보연구
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• 제32권3호
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• pp.127-151
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• 2013

본 연구는 메시지조절초점 유형이 복수모델의 광고효과에 미치는 영향을 파악하고자 하였다. 그 동안 광고모델, 특히 유명인의 광고의 효과성에 대한 논의는 지속적으로 이루어져 왔지만, 상대적으로 복수모델의 광고효과에 대한 연구는 미비한 실정이고 더욱이 모델의 수에 따른 효과에 영향을 주는 변수로서 메시지조절초점에 관한 연구는 매우 미흡한 상황이다. 본 연구는 복수모델광고가 제시되는 경우를 하나의 광고에 두 명의 광고모델이 동시에 제시되는 광고형태로 제한하여, 광고모델의 수에 메시지 조절초점의 정보처리 특이성을 적용하여 광고효과의 차이점을 검증 하였다. 구체적으로 복수의 광고모델의 기용 시 사회적 합의성 증가와 정보원의 원천확대 증가에 의해 광고모델과 소비자와의 관계성이 향상하는 효과가 나타나며 이러한 복수모델의 광고효과는 소비자가 메시지를 수용할 때 주로 관계적 정교화(relational elaboration) 정보처리를 하게 되는 향상초점메시지에서 보다 높을 것이라는 가설을 검증하였다. 광고 모델 수(단수모델/복수모델)${\times}$메시지 유형(향상초점메시지/예방초점메시지)의 실험결과, 메시지 유형에 상관없이 복수모델의 경우가 단수모델의 경우보다 광고태도, 브랜드 태도, 구매의도에서 모두 높은 결과가 나타났다. 또한, 복수모델의 경우에 향상초점메시지를 사용한 광고가 예방초점 메시지를 사용한 광고보다 광고태도, 브랜드 태도, 구매의도에서 모두 긍정적인 결과가 나타났다. 나아가 광고 모델의 수와 메시지조절초점간의 상호작용효과가 유의미한 것으로 나타났다. 본 연구는 학계는 물론 광고실무자들에게도 시사하는 점이 클 것이며 향후 광고모델수의 광고효과 연구의 확장에도 많은 기초를 제공하고 있다.

• 한국군사과학기술학회지
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• 제15권4호
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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.

• 대한기계학회논문집A
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• 제26권12호
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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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• 제11권4호
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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.

• 생명과학회지
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• 제20권11호
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• pp.1611-1616
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• 2010

W/O/W multiple emulsion의 산화에 미치는 surfactant micelle의 영향을 규명하기 위하여 W/O/W multiple emulsion에서 continuous phase로 전이되는 ferric iron의 양과 hydroperoxide의 양을 측정한 결과, continuous phase로 전이된 ferric iron과 hydroperoxide의 양은 첨가한 과량의 surfactant micelle에 의해, 저장기간이 길어질수록 증가하였다. Ferric iron을 함유한 W/O/W multiple emulsion의 지방산화 정도는 hydroperoxide와 TBA값 및 headspace hexanal을 측정하여 살펴본 결과 과량의 surfactant에 의해 산화는 감소하였다. 이상의 결과로 첨가된 과량의 surfactant에 의해 W/O/W multiple emulsion에서 prooxidant로 작용하는 ferric iron의 위치가 변화되어 산화를 줄일 수 있을 것으로 판단하였다.

• 지식경영연구
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• 제20권2호
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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.