• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1143-1152
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• 1999

A Mobile computing environment is a new paradigm which provides users with the access to information irrespective of users' location. A transaction scheduling method for the mobile computing environment must be designed so that database consistency is maintained with considering the limited performance of mobile hosts and the narrow bandwidth of a wireless network. The scheduling method using a lock has some problems: the high message overhead between a server and a mobile host for maintaining a lock and the high abort ratio of the mobile transactions owing to violating the serializability when a mobile host uses a cache. So, in this paper, we propose an efficient transaction management method using timestamp to resolve these problems. The proposed method is used in the environment under which a mobile host uses a cache having two versions for each cached data item and a server maintains several versions for each data item. So, even though a mobile transaction is executed during several broadcasting interval, can be committed. As a result, the proposed method can improve the commit ratio of the mobile transactions by maintaining multiversion for each data item and does not require the additional message exchange to schedule transactions by using timestamp.

• Journal of KIISE:Databases
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• v.30 no.4
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• pp.397-407
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• 2003

Transactions of updating spatial dta with mobile clients are log transactions because a user disconnected from a server surveys real features and updates them. In this environment, it is appropriate to exploit the optimistic approach based on the validation test in order to control the concurrency of transactions. On the contrary, the pessimistic concurrency control scheme makes transactions wait for a long time due to the lock. In this paper, we propose the surrogate transaction model and implement its manager for the S-S-M(Server-Surrogate PC-Mobile Client) structure which is appropriate for updating spatial data in mobile environments. In the S-S-M structure, the mobile client communicates with the server by the surrogate PC. We extend the validation condition in consideration of spatial relationships between spatial objects in this model. We also present the commit protocol where the user of a surrogate PC adjusts objects of the conflicted surrogate transaction to minimize costs for the abortion of the transaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4786-4793
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• 2012

In a recent mobile computing environment, the research for a transaction model have been actively carried out to deal with real-time transaction. However, the research for recovery model is relatively insufficient. Therefore, it would be very important for mobile recovery methods for database stability, just in case of data loss due to hand-off in mobile computing system. So, further efficient research should be keenly done to reduce I/O hand-off in mobile computing systems. SLL method increases I/O time due to sequential file. This paper have been suggested to efficient mobile recovery method in mobile computing system. Finally, it has been clearly demonstrated for system efficiency, conducting the performance assessment that currently proposed recovery system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.931-939
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• 2014

The Web or Mobile channel of previous Web access authentication system for a payment only provides the authentication of remote users, and does not provide the authentication between a user and a bank/financial institution. Therefore, this paper proposes the Transaction Certificate Mode(TCM) for a payment which can preserve the mutual authentication between a user and a bank/financial institution for Web-based payment systems. The proposed system has designed for wireless network instead of Secure Electronic Transaction (SET) designed for wired electronic transaction. In addition, this system with TCM is able to support an account-based transaction for wireless networks instead of a disadvantage of SET such as a card-based transaction for wired networks. Therefore, customers can check their balances without logging on their bank's web site again due to mutual authentication between a customer and his bank/financial institution.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.149-157
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• 2009

This study aims to empirically examine the factors influencing mobile channel loyalty. This study has been reviewed various theoretical research relating to mobile channel loyalty and transaction cost theory. The model was tested Structural Equation Modeling(SEM) using AMOS 7.0 analysis on the sample collected from 240 respondents. The result of hypothesis testing is as follows. First, asset specificity, uncertainty and transaction frequency were influenced by chanel satisfaction. Second, asset specificity was influenced negatively by chanel preference. Third, chanel satisfaction was influenced positively by chanel preference. Finally, chanel satisfaction and chanel preference were influenced positively by chanel loyalty.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.6
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• pp.913-928
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• 2014

This study estimated a dual path model to predict consumers' intention to use a QR code virtual store by the effect of a mobile transaction system and a facilitating condition that also examined the role of experience and the use of an intention model in the context of a QR code virtual store. A longitudinal field study was conducted at selected QR code virtual stores. A questionnaire containing mobile transaction system, facilitating condition, performance expectancy, effort expectance, and intention to use was administered at two different points in time: Initial use (T1) and the second use after one month (T2). This study sampled 109 subjects who voluntarily participated in field studies twice at different time points (pooled sample=218). Participants were asked to visit at the QR code virtual store and undertake shopping tasks on their smartphones. The estimated dual path model showed that a mobile transaction system had a positive effect on performance expectancy, which influenced intention to use; however, facilitating condition had a positive effect on effort expectancy, but the effort expectance did not lead to intention to use. The effort expectance significantly also affected the performance expectance influencing intention to use QR code virtual stores. It was also found that use experience moderated the effect of mobile transaction systems on performance expectancy. The findings discussed a critical and success factor in consumer technology acceptance and use over time. A managerial implication was also discussed to capture potential users by emphasizing performance expectancy with the superiority of an innovative system or consumer facilitating condition as external resources in the introduction stage of new technology.

• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.535-546
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• 2015

Using mobile bookstore application is increasing in accordance with the proliferation of internet and mobile devices. In this circumstances, the purpose of this study is to explore the factors regarding to mobile bookstore application quality evaluation are effecting to customer satisfaction and reuse intention. Thus information, transaction, design, communication, ubiquitous access, personalization, safety are set as a quality evaluation factor. And it is analyzed the effect of these factors to customer satisfaction and reuse intention with path analysis method. As the result, transaction, ubiquitous access, personalization, safety factors effected customer satisfaction and customer satisfaction effected reuse intention. These results show that user mainly access mobile bookstore application for purchasing book. Thus it is important for mobile bookstore operator to keep the application accessed anytime, and serve personalized information, and simplify transaction process, and intensify security for protecting personal or transaction information.

• The KIPS Transactions:PartD
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• v.11D no.2
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• pp.339-350
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• 2004

A broadcast method in mobile computing environments which have very large client populations solves the problem of low bandwidth. But most of previous proposed concurrency control protocols are restricted to read-only transactions from mobile client. In this paper, we propose the UTSM-ARM method which uses caching and broadcast method, and allows update transactions in mobile client. The UTSM-ARM decides the validation of cache data consistency with the dynamic update pattern ratio of accessed cached data. Also, the timestamps of accessed cached data and transaction in mobile client guarantee the serializable execution of mobile transactions. As a result, UTSM-ARM makes efficiently use of the asymmetric bandwidth of broadcast environment and can Increase the transaction throughput.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.131-143
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• 2006

The rapid growth of mobile communication technology has provided the expansion of mobile internet services, particularly mobile realtime transaction takes much weight among mobile fields. Current mobile transaction service has serious problems which check its development, such as low bandwidths, hand over, expensive charge system, and low response time. but, There is an increasing demand for various mobile applications to process transactions in a mobile computing fields. In mobile computing environments. A mobile host computing system demands for new concurrency control method to use the bandwidth efficiently, to improve the bottleneck and the response time of transactions. This study suggests about an efficient concurrency control in a mobile computing environment. Concurrency control method in existing method uses two phases locking method. In this method, Many clients can't use the same segment simultaneously, and so useless waiting time increases. The characteristic of this proposed method unlike existing one, Enable the transaction approaching different data in the same segment to minimize the useless waiting time by permitting segments, and therefore improves the coexistence of system. Also, It shows the algorithm of the proposed concurrence control method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.648-651
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• 2002

In data broadcast environments, data is disseminated from a small number of sewers to a much larger number of clients. The advancing technology of hardware and increasing needs of users' have extended a broadcast environments. A mobile environment use the data broadcasting. A user carrying a portable computer can submit the operations of a transaction. Some limitations such as the poor-resource, user mobility, and low bandwidth are difficult to apply traditional transaction management to the mobile environments. So, the new mechanisms are needed and one of the them is the correctness criteria of transactions. Serializability is the most used criteria, but serializability is not appropriate to the broadcast environment because unnecessary abort and additional message exchanges are occurred. Hence, in this paper, we will address the need of the new correctness criteria weaker than serializability and describe the adoption of the update consistency.