• Knowledge Management Research
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• v.8 no.2
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• pp.31-52
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• 2007

Since the introduction of knowledge management systems, many studies have attempted to analyze its performance and identify the success factors. However, few studies have investigated the relationship between KMS technology characteristics and its quality. This paper attempts to categorize KMS technology functions into socialization, externalization, combination and internalization and then find the relationship between these functions and KMS quality. It also attempts to investigate the moderating effect of task characteristics in this relationship. Our research frame is derived from the well known task-technology fit model and the related KMS performance studies. A survey was conducted from 157 KMS users. It is found that both externalization and combination are important for KMS quality and this quality influences the KMS performance. Furthermore, it is confirmed that the task characteristics can moderate between the KMS technology and its quality.

• Journal of the Korean Data and Information Science Society
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• v.25 no.4
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• pp.903-914
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• 2014

The inverse Weibull distribution has been proposed as a model in the analysis of life testing data. Also, inverse Weibull distribution has been recently derived as a suitable model to describe degradation phenomena of mechanical components such as the dynamic components (pistons, crankshaft, etc.) of diesel engines. In this paper, we derive the approximate maximum likelihood estimators of the scale parameter and the shape parameter in the inverse Weibull distribution under multiply type-II censoring. We also develop four modified empirical distribution function (EDF) type tests for the inverse Weibull or extreme value distribution based on multiply type-II censored samples. We also propose modified normalized sample Lorenz curve plot and new test statistic.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.622-626
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• 2002

Growth records over six generations of 686 pigs in SD-II Swine Line were used to estimate the genetic and phenotypic covariance functions for body weight as longitudinal data. A random regression model with Legendre polynomials of age as independent variables was used to estimate the (co)variances among the regression coefficients, thus the coefficients of genetic and permanent environmental covariance functions by restricted maximum likelihood employing the average information algorithm. The results showed that, using litter effect as additional random effect, a reduced order of fit did not describe the data adequately. For all five orders of fit, however, the change trends of genetic and phenotypic (co)variances were very similar from ${\kappa}$=3 onwards.

• Journal of the Korean Statistical Society
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• v.29 no.2
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• pp.201-217
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• 2000

The method of generalized estimating equations (GEE) has become very popular for the analysis of longitudinal data. We extend this work to the use of M-estimators; the resultant regression estimates are robust to heavy tailed errors and to outliers. The proposed method does not require correct specification of the dependence structure between observation, and allows for heterogeneity of the error. However, an estimate of the dependence structure may be incorporated, and if it is correct this guarantees a higher efficiency for the regression estimators. A goodness-of-fit test for checking the adequacy of the assumed M-estimation regression model is also provided. Simulation studies are conducted to show the finite-sample performance of the new methods. The proposed methods are applied to a real-life data set.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3992-4005
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• 2018

In our current information-based society in which knowledge is a fundamental asset to production, the capability to utilize information and produce knowledge with the use of information technology (IT) has become essential to learning. Massive Open Online Courses (MOOCs) have recently been introduced in light of such changes and are recognized as an alternative to open education. MOOCs' capabilities are being acknowledged in lifelong education in terms of reeducation and knowledge sharing, and also in terms of improving teaching quality, and improving university students' levels of creativity and integrated thinking by supporting high-level content and teaching. Therefore, this study presents an extended research model that combines information system (IS) continuance and task-technology fit models. Our study researches previous literature, revealing factors of continuous use after accepting MOOCs from the learner's perspective, and analyzes the model empirically. The ideal environment for MOOCs learners is evaluated, and a strategic approach to the successful settlement and diffusion of MOOCs is presented based on this study's findings.

• Communications for Statistical Applications and Methods
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• v.24 no.2
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• pp.155-162
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• 2017

In this paper we propose influence measures for two basic goodness-of-fit statistics, the coefficient of determination $R^2$ and test statistic F in the linear regression model using the deletion method. Some useful lemmas are provided. We also express the influence measures in terms of basic building blocks such as residual, leverage, and deviation that showed them as increasing function of residuals and a decreasing function of deviation. Further, the proposed measure reduces computational burden from O(n) to O(1). As illustrative examples, we applied the proposed measures to the stackloss data sets. We verified that deletion of one or few influential observations may result in big change in $R^2$ and F-statistic.

• ETRI Journal
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• v.36 no.6
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• pp.1008-1015
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• 2014

In this paper, we present a method for reconstructing a surface mesh animation sequence from point cloud animation data. We mainly focus on the articulated body of a subject - the motion of which can be roughly described by its internal skeletal structure. The point cloud data is assumed to be captured independently without any inter-frame correspondence information. Using a template model that resembles the given subject, our basic idea for reconstructing the mesh animation is to deform the template model to fit to the point cloud (on a frame-by-frame basis) while maintaining inter-frame coherence. We first estimate the skeletal motion from the point cloud data. After applying the skeletal motion to the template surface, we refine it to fit to the point cloud data. We demonstrate the viability of the method by applying it to reconstruct a fast dancing motion.

• The Korean Journal of Applied Statistics
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• v.25 no.6
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• pp.1037-1047
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• 2012

The generalized linear mixed model(GLMM) is widely used in fitting categorical responses of clustered data. In the numerical approximation of likelihood function the normality is assumed for the random effects distribution; subsequently, the commercial statistical packages also routinely fit GLMM under this normality assumption. We may also encounter departures from the distributional assumption on the response variable. It would be interesting to investigate the impact on the estimates of parameters under misspecification of distributions; however, there has been limited researche on these topics. We study the sensitivity or robustness of the maximum likelihood estimators(MLEs) of GLMM for counts data when the true underlying distribution is normal, gamma, exponential, and a mixture of two normal distributions. We also consider the effects on the MLEs when we fit Poisson-normal GLMM whereas the outcomes are generated from the negative binomial distribution with overdispersion. Through a small scale Monte Carlo study we check the empirical coverage probabilities of parameters and biases of MLEs of GLMM.

• Journal of Information Technology Services
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• v.17 no.4
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• pp.1-19
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• 2018

Effective internal communication is known to have a positive impact on business performance, but there is a lack of research on the effects of online channels for workplace communication. This study using regression analysis examines how task-technology fit, information richness, self-efficacy, perceived ease of use, and perceived usefulness related to online communication channels affect not only the satisfaction with the tools but also the effectiveness of them. Additionally, we verify how the organizational culture of online and offline communication shows the control effect. As a result, all five variables were positively correlated with internal communication channels satisfaction, and we found that the organizational culture of online and offline communication controls the relationship between online communication channels satisfaction and effectiveness.

• Journal of Distribution Science
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• v.17 no.2
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• pp.77-89
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• 2019

Purpose - This study presents the relationships between parent brand-self image congruence, parent brand -functional congruity, perceived fit between parent brand and extension product, and consumer's attitude toward extension product using the structural equation model. As for preceding concepts having a direct effect on consumer's attitude toward brand extension, the study focuses on parent brand-self image congruence and parent brand-functional congruity. It also looks at the effect of parent brand-self image congruence and parent brand-functional congruity on the consumer's attitude toward extension product and identifies if the perceived fit between parent brand and extension product is a concept playing a mediating role between parent brand-self image congruence or parent brand-functional congruity and consumer's attitude toward brand extension product. Research design, data, and Methodology - SPSS for Windows 18.0 and AMOS 18.0 were used for data analysis. Then, the Cronbach's α coefficient was obtained using SPSS for Windows 18.0 to measure reliability. In addition, the convergence and discriminative measures of the measured items were statistically verified using AMOS 18.0. Finally, we have validated a path model and a parameter model in which brand personality-self-matched attitude toward brand extension. Results - Studies have shown that the impact of parent brand-self image consistency and parent brand-functional consistency on the attitude of extended products was positive. Perceived fit between parent brand and extension products has been shown to play a role of intermediary between parent brand-self image congruence and consumer attitudes to extended products. However, perceived fit between parent brand and extension products did not play a role as intermediary between the parent brand-functional congruity and the attitude toward the extended product. Finally, in relation to the causal relationship between parent brand-congruity (self image/functionality) and attitudes to extended products. The effect of parent brand-functional coherency on attitudes toward extended products was found to be greater in groups with higher involvement than in those with lower involvement. Conclusions - Although few studies have been done on what variables mediated when parent brand-self image consistency and parent brand-functional coherency affect consumer attitude, this paper is significant in finding whether perceived fitness between the parent brand-congruity and the extension product is mediated.