• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1213-1220
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• 2004

With the significant advances in mobile computing technology, there is an increasing demand for various mobile applications to process trans-actions in a real-time. When remote data access is considered in a mobile environment, data access delay becomes one of the most serious problems in meeting the deadline of real-time transaction. The mobile real-time transaction should be assured not only correctness of result of trans-action but also completion time of transaction. In this paper, we propose an optimistic concurrency control method to solve conflict among mobile real-time transactions. It minimizes influence on the cascade abort and delay of transactions that occur by disconnection and hand over in a mobile environment.

• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.533-542
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• 2001

In this paper, we present a scheduling method for real-time mobile transaction manager in mobile computing environment. The proposed method checks whether a transaction is executable or not. It is able to by considering not only the deadline of real-time data in mobile hosts. And then, it schedules the real-time mobile transactions by making optimal execution window based on the priority queue, while considering transaction value and deadline. Disconnection with mobile hosts is monitored in selecting the transaction for execution. Using the proposed method reduces the number of restarting times after transaction aborts which is caused by the violation of the validity constraints of real-time data. And in has merits of maximizing the sum of values of real-time mobile transactions which meet the deadline. The performance evaluation demonstrates that the number of committed real-time transactions within the deadline is improved by 20%. This method can be used in real-time mobile transaction manager is such environments as cellular communications, emergency medicine information system and so on.

• 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 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 Internet Computing and Services
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• v.17 no.5
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• pp.25-32
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• 2016

There has been a rapid growth in the development of mobile application resulting from its wide usage for online transaction, data storage and exchange of information. However, an important issue that has been overlooked is the lack of emphasis on the security issues at the early stage of the development. In fact, security issues have been kept until the later stage of the implementation of mobile apps. Requirements engineers frequently ignore and incorrectly elicit security related requirements at the early stage of mobile application development. This scenario has led to the failure of developing secure and safe mobile application based on the needs of the users. As such, this paper intends to provide further understanding of the real challenges in extracting security attributes for mobile application faced by novice requirements engineers. For this purpose, two experiments on eliciting security attributes requirements of textual requirements scenario were conducted. The performance related to the correctness and time taken to elicit the security attributes were measured and recorded. It was found that the process of eliciting correct security attributes for mobile application requires effort, knowledge and skills. The findings indicate that an automated tool for correct elicitation security attributes requirement could help to overcome the challenges in eliciting security attributes requirements, especially among novice requirements engineers.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.6
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• pp.63-69
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• 2009

The decentralized and open characteristic of the internet, along with the mobility and portability of mobile communication, and the interactivity of the internet and mobile communications all have been grafted to enable the creation of wireless internet in our lives, bringing about a lot of change. However, existing system management software solutions show limitations in time and space, as well as problems such as uncertain error messages, and also difficulty providing swift assistance or real time emergency support. Therefore, a wireless remote control system has been designed and implemented in this thesis, which is capable of managing and monitoring remote systems using mobile communication devices (Mobile Phone, PDA, Smart Phone, Webpad) for realtime control. The implemented real time wireless remote control system provides remote server management functions, error or event message functions, log record functions, authentication function via mobile devices and system performance evaluation function classified by client transaction.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.4
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• pp.141-147
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• 2003

Security of the electronic commercial transaction especially through the mobile communication network is gaining its significance due to rapid development of information and communication related fields. For that, some kind of cryptographic algorithm is already in use for the smart card. However, the growing needs of handling multimedia and real time communication bring the smart card into more stringent use of its resources. Therefore, we proposed a hybrid cryptosystem of the smart card to facilitate multimedia communication and real time communication.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1525-1540
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• 2015

Due to a rapid advancement in the electronic commerce technology, the payment method varies from cash to electronic settlement such as credit card, mobile payment and mobile application card. Therefore, financial fraud is increasing notably for a purpose of personal gain. In response, financial companies are building the FDS (Fraud Detection System) to protect consumers from fraudulent transactions. The one of the goals of FDS is identifying the fraudulent transaction with high accuracy by analyzing transaction data and personal information in real-time. Data mining techniques are providing great aid in financial accounting fraud detection, so it have been applied most extensively to provide primary solutions to the problems. In this paper, we try to provide an overview of the research on data mining based fraud detection. Also, we classify researches under few criteria such as data set, data mining algorithm and viewpoint of research.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.187-194
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• 2003

Main Memory storage system can increase the performance of the system by assigning enough slack time to real-time transactions. Due to its high response time of main memory devices, main memory resident data management systems have been used for location management of personal mobile clients to cope with urgent location related operations. In this paper we have developed a multi-threaded main memory storage system as a core component of real-time retrieval system to handle a huge amount of readers and writers of main memory resident data. The storage system is implemented as an embedded component which is working with the help of a disk resident database system. It uses multi-threaded executions and utilizes latches for its concurrency control rather than complex locking method. It only saves most recent data on main memory and data synchronization is done only when disk resident database asks for update transactions. The system controls the number of read threads and update threads to guarantee the minimum requirements of real-time retrievals.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.4
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• pp.229-236
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• 2005

This paper presents a system level architecture evaluation technique that leverages transaction level modeling but also significantly extends it to the realm of system level performance evaluation. A major issue lies with the modeling effort. To reduce the modeling effort the proposed technique develops the concept of worst case scenarios. Since the memory controller is often found to be an important component that critically affects the system performance and thus needs optimization, the paper further addresses how to evaluate and optimize the memory controllers, focusing on the test environment and the methodology. The paper also presents an industrial case study using a real state-of-the-art design. In the case study, it is reported that the proposed technique has helped successfully find the performance bottleneck and provide appropriate feedback on time.