• Journal of the Korea Society for Simulation
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• v.24 no.4
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• pp.89-96
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• 2015

The mediation methods suggested by Baron and Kenny, Sobel, Aroian and Goodman, have widely used to test the mediating effect. However, as there are many problems in statistical test power, as well as statistical accuracy, a bootstrapping technique has been suggested as an alternative. In this paper, we adopt the phantom variables based on the bootstrapping technique to test the mediating effect in multiple mediator model consisting of three or more mediating variables. In particular, we formulate the multiple mediator model for analyzing the relations among organizational resources, the absorption capacity as mediating variables and technology commercialization capabilities. And using the bootstrapping approach, we analyzed the mediating effect of the absorption capacity by setting of phantom variables and calculated total indirect effect size and the statistical significance. The empirical results are as follows. First, we confirmed that the bootstrapping approach and the phantom variable is the very efficient and systematic mediation method. Second, we recognized that there is a difference in the mediating characteristics of the absorption capacity depending on the resource characteristics of human resources and material resources obviously.

• Journal of Information Technology Applications and Management
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• v.18 no.4
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• pp.21-40
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• 2011

Emoticons perform an important role as an enhancement to written communication, in areas such as Windows Live Messenger instant messaging, e-mails, mobile Short Message Services (SMS), and others. Emoticons are graphic images used in communications to indicate the feelings of people exchanging messages via mobile technology. In this research, the perceived usefulness of the emoticon in mobile phone text messages is verified with consumers using the five construct model of Huang. A K-means clustering technique for separating three groups based on levels of perceived usefulness of mobile emoticons is used with a structural equation model test using Smart PLS 2.0, and the bootstrap re-sampling procedure. We analyzed relationships among use of emoticons, enjoyment, interaction, information richness, and perceived usefulness. The results show there are relationships among use of emoticons, enjoyment, interaction, perceived usefulness, and information richness, however enjoyment of emoticons did not significantly affect the perceived usefulness of messages with emoticons alone. The results suggest emoticons have different affects on emotion in both mobile, and Messenger contexts. Our study did not consider more detailed media properties, and thus more studies are needed. Our research results contribute to mobile communication activation, provides companies with an understanding of key characteristics of consumers who use emoticons, and provides useful implications for improving management and marketing strategies.

• ALGAE
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• v.20 no.4
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• pp.261-270
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• 2005

We analyzed chloroplast ATP synthetase beta subunit(atpB) sequences from 32 strains of the zygnemophycean green algae, Staurastrum, Staurodesmus, and a single species of Xanthidium. A total of 42 atpB sequences including previously published ones was aligned for phylogenetic analyses. The phylogenies were validated with bootstrap analysis and Kishino-Hasegawa test. Taxa of Staurastrum excluding S. muticum indicate that they can be characterized by taxa having the ornamented cell wall or the process of cells. However, the genus Staurodesmus was grouped with taxa having the smooth cell wall and the absence of process or arms. The results suggest that the genus Staurodesmus could be extended to include Staurastrum muticum, Desmidium, Onychonema and Xanthidium. Further taxon sampling of Staurodesmus and putative relatives is necessary for a solid classification of the genus.

• Knowledge Management Research
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• v.11 no.5
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• pp.59-78
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• 2010

In this paper, we arrange the concept of 'Green' in SCM after literature study of Green SCM and investigate causal relationships between influencing factors, practice level and environmental performance focused on Korean firms empirically and conduct path analysis for hypothesis test using partial least squares regression with bootstrap. Firstly, we divide influencing factors of Green SCM into environmental and organizational factors through the previous studies of innovation diffusion theory and environmental management theory, and then we selected 'uncertainty', 'competitiveness' as the environmental factors and 'top management support', 'perceived benefit', 'training' as the organizational factors. Secondly, we classify practice level of Green SCM into 'internal environmental management', 'green purchasing', 'eco-design'. Finally, we selected 'financial performance', 'environmental performance' as the organizational performance. We conducted a survey on the middle manager of manufacturing companies implementing SCM and an empirical analysis. The results of analysis show that there exist causal relationships between influencing factors, practice level, and environmental performance of Green SCM. We expect that the result of this study will suggest useful information to managers who are responsible for SCM to design and execute Green SCM in strategic perspectives.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.47.1-47.1
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• 2017

We study the alignment of kinematic position angles (PAkin) of early-type galaxies in the Virgo cluster using Atlas3D data. The PAkin represent the direction of the angular momentum of the galaxies better than the photometric position angles. Therefore, the alignment of their PA$_{kin}$ is a useful tool to trace the momentum direction. The early-type galaxies in the Virgo cluster have been known to be distributed as filamentary structures inside the cluster. We found that their PAkin are aligned to two directions of 20degree and -80degree. This fact is confirmed using the bootstrap test, and that is, the two alignment angles are statistically significant. Besides, these two angles are surprisingly aligned parallel to the filamentary structures inside the cluster. These results suggest that early-type galaxies were formed by major merging in the filament structures and then fall into the Virgo cluster while maintaining their position angles.

• Journal of Information Technology Application
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• v.3 no.4
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• pp.119-134
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• 2001

Improving software product quality is a key to increasing user satisfaction and to achieving competitive edge. There are two approaches to assure high software product quality; development process-oriented and product-oriented. There have been many efforts for improving software quality through process certification, for example, CMM, ISO 9000 family, ISO/IEC 12207, SPICE and Bootstrap. However, a good process alone cannot guarantee good product quality. A need for the evaluation of software product quality by an independent third party is growing rapidly for several reasons. We are concerned with an application of Statistical Quality Control (SQC) to the evaluation of software product quality to obtain the efficiency of evaluation processes and the objectivity of evaluation results. Methods for selecting test cases using a random sampling approach have been discussed and methods for selecting acceptance criteria with respect to software product quality have also been suggested.

• The Korean Journal of Applied Statistics
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• v.17 no.3
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• pp.489-498
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• 2004

In this paper, a new form of linear models referred to as generalized weighted linear models is proposed. The proposed models assume that the relationship between the response variable and explanatory variables can be modelled by a distribution function of the response mean and a weighted linear combination of distribution functions of covariates. This form addresses a structural problem of the link function in the generalized linear models in which the parameter space may not be consistent with the space derived from linear predictors. The maximum likelihood estimation with Lagrange's undetermined multipliers is used to estimate the parameters and resampling method is applied to compute confidence intervals and to test hypotheses.

• Mycobiology
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• v.47 no.4
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• pp.408-414
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• 2019

Crinum asiaticum and Hymenocallis littoralis, commonly known as spider lilies are bulbous perennial and herbaceous plants that widely planted in Malaysia as ornamental. During 2015-2016, symptom of leaf blight was noticed on the hosts from several locations in Penang. The symptom appeared as irregular brown to reddish lesions surrounded by yellow halos. As the disease progressed, the infected leaves became blighted, dried, and fell off with the presence of black microsclerotia and pycnidia on the lesions parts. The present study was conducted to investigate the causal pathogen of leaf blight on C. asiaticum and H. littoralis. Based on morphological characteristics and DNA sequences of internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-α) gene, the causal pathogen was identified as Macrophomina phaseolina. Phylogenetic analysis of combined dataset of ITS and TEF1-α grouped the isolates studied with other isolates of M. phaseolina from GenBank. The grouping of the isolates was supported by 96% bootstrap value. Pathogenicity test proved the role of the fungus in causing leaf blight on both hosts.

• Journal of Species Research
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• v.4 no.1
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• pp.49-56
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• 2015

Zeuzera is one of the most important wood borer pests in South East Asia. Like of most other genera of moths, the systematic of this genus is still in dispute, especially on the monophyly and the relationship within this genus due to the fact that genus is very varied. This genus was defined based on external characters only such as cross vein Sc-Rs present, humeral plate approximately triangular in shape and anal plate moderately long to moderately short. Therefore, the monophyly of this genus need to be evaluated based on more comprehensive data. To clarify the monophyly of the genus Zeuzera, to reveal the phylogenetic relationships among the Indonesian species, and to establish the genetic characters of Indonesian Zeuzera, we analyzed seven species of Indonesian Zeuzera including three other species distributed around the world based on nucleotide sequence variation across a 580-bp region in the CO I gene. The results showed that the monophyly of Zeuzera was supported by bootstrap tests at the MP and ML tree building methods (>95%). Genus Zeuzera was divided into two groups (A and B) with Z. borneana was excluded from the two groups and occupied at the basal node. Indonesian species was distributed into two different clades. CO I gene alone was able to fully resolve the relationships among species within clade B. However, further investigations were needed by including more species and other genes that the more conserved to test the validity of the phylogenetic hypothesis proposed here.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.171-180
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• 2016

Basel committee suggests using Value-at-Risk (VaR) and expected shortfall (ES) as a measurement for market risk. Various estimation methods of VaR and ES have been studied in the literature. This paper compares semi-parametric methods, such as conditional autoregressive value at risk (CAViaR) and conditional autoregressive expectile (CARE) methods, and a Gaussian quasi-maximum likelihood estimator (QMLE)-based method through back-testing methods. We use unconditional coverage (UC) and conditional coverage (CC) tests for VaR, and a bootstrap test for ES to check the adequacy. A real data analysis is conducted for S&P 500 index and Hyundai Motor Co. stock price index data sets.