• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1144-1150
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• 2015

Presence information provides various informations about users such as on-line status, current location, network connection method and connection address, and there are two kinds of presence information, SIP(Session Initiation Protocol) based presence information and XMPP(Extensible Massaging and Presence Protocol) based presence information. In this paper, a multiple server architecture that can handle these two kinds of presence information has been proposed. In this architecture, severs are added dynamically according to number of users to provide system scalability, and load of each server can be effectively controlled. In this system, a new XMPP stanza architecture and presence information data format are designed for load control. Furthermore message exchanging procedures between servers and users for dynamic server control has been also suggested. The performance of the proposed system has been analysed by simulation.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.79-85
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• 2013

In SIP(Session Initiation Protocol) environment, the presence server should process SIP SUBSCRIBE request messages including multiple presence resources addresses from users, and also precess massive notification messages from the subscribed presence resources. The load of the presence server increases as number of users increase, and it limits system extendability. Therefore a new multiple presence servers architecture has been suggested in this research. In this architecture presence servers can be added dynamically and each server's load can be controlled effectively as number of users increase. Each presence server can monitor current load status of entire presence system by using presence event notification package which newly has been suggested in this paper. When a particular presence server's load increases over predefined limit, the presence service processing is distributed by selecting a server which has the smallest load, or by generating a new server dynamically. In this system the overall load of the entire system can be controlled optimally and extendability of the system can be increased. For this purpose a new presence event notification package and presence information data format have been suggested. The performance of the proposed system has been evaluated by experiments. They shows 44.3% increase in SUBSCRIBE message processing time, and 43.1% increase in Notification message processing time.

• Journal of the Korean Data and Information Science Society
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• v.4
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• pp.131-136
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• 1993

We shall consider the trends of correlation coefficient between the smallest and largest observations in the Weibull model in the presence of an unidentified outlier, and derive the density functions of order statistics by the permanent theory.

• Journal of the Korean Data and Information Science Society
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• v.6 no.1
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• pp.85-96
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• 1995

The purpose of this paper is to propose the kernel density estimator and the jackknife kernel density estimator in the presence of k's unidentified outliers, and to compare the small sample performances of the proposed estimators in a sense of mean integrated square error(MISE).

• Asia pacific journal of information systems
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• v.33 no.2
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• pp.367-388
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• 2023

This study aimed to examine the factors of information-sharing intention on social networking sites (SNSs) by integrating the perspectives of the institution-based trust, social presence, and theory of reasoned action (TRA). An empirical survey was conducted and 364 valid respondents were collected from Facebook (FB) users in Taiwan. These data were analyzed against the research model using the partial least squares (PLS) structural equation modeling. The findings revealed that situational normality and structural assurance have a positive influenced user trust in SNSs which in turn increased their information-sharing attitudes. Furthermore, the subjective norms, user information-sharing attitudes and social presence of the SNSs were shown to have a positive influenced on user information sharing intention. Finally, this study provided several important theoretical and practical implications to understand factors affecting information-sharing intention on SNSs.

• Communications for Statistical Applications and Methods
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• v.25 no.1
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• pp.43-60
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• 2018

This paper considers the use of classical and Bayesian inference methods to analyze data generated by variables whose natural behavior can be modeled using asymmetric distributions in the presence of left censoring. Our approach used a $L{\grave{e}}vy$ distribution in the presence of left censored data and covariates. This distribution could be a good alternative to model data with asymmetric behavior in many applications as lifetime data for instance, especially in engineering applications and health research, when some observations are large in comparison to other ones and standard distributions commonly used to model asymmetry data like the exponential, Weibull or log-logistic are not appropriate to be fitted by the data. Inferences for the parameters of the proposed model under a classical inference approach are obtained using a maximum likelihood estimators (MLEs) approach and usual asymptotical normality for MLEs based on the Fisher information measure. Under a Bayesian approach, the posterior summaries of interest are obtained using standard Markov chain Monte Carlo simulation methods and available software like SAS. A numerical illustration is presented considering data of thyroglobulin levels present in a group of individuals with differentiated cancer of thyroid.

• Journal of The Korean Association of Information Education
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• v.14 no.2
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• pp.175-187
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• 2010

This study aims to analyze the causal relationship among teaching, cognitive, social presence and the learning outcome. It also provides the base data on the development of cyber education and its management strategies. During the first semester of 2009, 802 students at W cyber university completed surveys about their learning experience in teaching presence, cognitive presence, social presence, and learning outcome. The results indicated that there was a meaningful effect of teaching presence and cognitive presence on satisfaction, and that of cognitive presence on academic achievement. Based on these results, this study suggests instructional design methods and management strategies to improve the quality of learning in cyber universities.

• Asia pacific journal of information systems
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• v.23 no.4
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• pp.85-102
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• 2013

This study proposes a web presence readiness model based on pre-payment service functions and a post-payment service function both of which embrace the major concerns of customers in the online purchasing context. Based on the concept of customer utility from the product itself and instrumental utility, the research model suggests four antecedents including, Perceived Economic Benefits, Product Search Support Quality, e-Shopping Method Diversity, and Post-Payment Support Quality. We empirically examined a proposed research model using data collected from online rating company websites. Among the four antecedents, post payment support quality is found to be the most influential determinant of customer evaluation on e-commerce websites. Based on the empirical results, the current study proposes an alternate model of web presence readiness. The findings of this study may provide an insight to field practitioners designing commercial websites. The implications and future research directions are further discussed.

• Journal of the Korean Data and Information Science Society
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• v.14 no.3
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• pp.553-559
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• 2003

The reliability modeling of distributed systems requires a good understanding the reliability of the components. For thousands of web users, competitiveness in web services means a successful presence on the web. Mean time between failures of a web site on SOAP12/HTTP is considered, where SOAP12 is a protocol intended for exchanging structured information in a decentralized, distrbuted environment. Data were collected from statlab.cam.ac.uk/webstat/stat.html via the internet.

• The Journal of Information Systems
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• v.32 no.1
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• pp.23-51
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• 2023

Purpose: Live commerce is a new type of electronic commerce in combination with live streaming services. It is expected to increase virtual presence in the context of online shopping by overcoming a lack of social interactions between sellers and buyers which have been raised as a limitation in electronic commerce. Drawing on the studies of communication media, this study examines how live commerce contributes to the increase of virtual presence which consists of telepresence and social presence. Telepresence refers to a buyer's perception that he or she is present at the physical shopping mall during live shopping streaming whereas social presence refers to a buyer's perception of social interaction with a seller which is human warm, social, sensitive, and personal. In this study, we verify key determinants of virtual presence and its consequences. More specifically, this study proposes virtual presence contributes to the increase of buyers' trust in products and further purchase intentions. Furthermore, we verify influential factors of virtual presence from the technical and influencer perspectives of live commerce. Design/methodology/approach: To test the proposed hypotheses, the partial least squares (PLS) analysis is conducted with a total of 250 data collected on users with experience in the TaoBao live streaming shopping platform. Findings: The results show that first, telepresence and social presence are increased by visibility, media richness and attractiveness in the context of live shopping streaming. Second, buyers' trust in product trust and purchase intentions are positively influenced by telepresence and social presence. Finally, buyers' trust in product has a direct, positve effect on their purchase intentions. Overall, the findings offer new insights into the studies of electronic commerce by introducting the concepts of virtual presence and media richness from the literature of communication media in the field of live commerce.