• The Journal of Economics, Marketing and Management
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• 제9권2호
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• pp.1-10
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• 2021

Purpose: In this work, we examine several time series models to predict internet and mobile transaction amount in South Korea, whereas Jeong (2020) has obtained the optimal forecasts for online shopping transaction amount by using time series models. Additionally, optimal forecasts based on the model considered can be calculated and applied to the Corona 19 situation. Research design, data, and methodology: The data are extracted from the online shopping trend survey of the National Statistical Office, and homogeneous and comparable in size based on 46 realizations sampled from January 2007 to October 2020. To achieve the goal of this work, both multiplicative ARIMA model and Holt-Winters Multiplicative seasonality method are taken into account. In addition, goodness-of-fit measures are used as crucial tools of the appropriate construction of forecasting model. Results: All of the optimal forecasts for the next 12 months for two online shopping transactions maintain a pattern in which the slope increases linearly and steadily with a fixed seasonal change that has been subjected to seasonal fluctuations. Conclusions: It can be confirmed that the mobile shopping transactions is much larger than the internet shopping transactions for the increase in trend and seasonality in the future.

• The KIPS Transactions:PartD
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• 제12D권1호
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• pp.21-30
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• 2005

In mobile computing environments, a mobile host caches the data to use the narrow bandwidth efficiently and improve the response time. A server periodically broadcasts the update data for maintaining the cache consistency of a mobile host. However, a method for maintaining cache consistency using periodic invalidation report has a problem that defers the commit decision of a mobile transaction to guarantee its serializable execution. In this paper, we propose CCM-AD method that guarantees the serializable execution of a mobile transaction even in the case that it is executed using cached data. As CCM-AD method guarantees the serializable execution of mobile transactions by using the intersection between the data broadcast to mobile host and the data updated at server. Then the CCM-AD method can reduce the delay of commitment decision of a mobile transaction. Also our method can reduce the size of invalidation report.

• The KIPS Transactions:PartC
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• 제10C권3호
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• pp.325-334
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• 2003

In stateless server, if an asynchronous cache invalidation scheme attempts to support local processing of read-only transaction in mobile client/sever database systems, a critical problem may occur ; the asynchronous invalidation reports provide no guarantees of waiting time for mobile transactions requesting commit. To solve this problem, the server in our algorithm broadcasts two kind of messages, asynchronous invalidation report to reduce transaction latency and periodic guide message to avoid the uncertainty of waiting time for the next invalidation report. The asynchronous invalidation report has its own sequence number and the periodic guide message has the sequence number of the most recently broadcast asynchronous invalidation report. A mobile client checks its cache validity by using the sequence numbers of these messages.

• Journal of Internet Computing and Services
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• 제6권1호
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• pp.65-72
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• 2005

Flash memories are one of best media to support portable computers in mobile computing environment. The features of non-volatility, low power consumption. and fast access time for read operations are sufficient grounds to support flash memory as major database storage components of portable computers. However. we need to Improve traditional transaction management scheme due to the relatively slow characteristics of flash operation as compared to RAM memory. In order to achieve this goal. we devise a new scheme called flash-aware transaction management (FATM). FATM improves transaction performance by exploiting SRAM and W-Cache, We also propose a simulation model to show the performance of FATM. Based on the results of the performance evaluation, we conclude that FATM scheme outperforms the traditional scheme.

• The KIPS Transactions:PartD
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• 제9D권2호
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• pp.185-194
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• 2002

Most of mobile computing systems allow mostly read-only transactions from mobile clients for retrieving various types of Information such as stock data, traffic information and news updates. Since previous concurrence control protocols, however, do not consider such a particular characteristics, the performance degradation occurs when previous schemes are applied to the broadcast environment. In this paper, we propose OCC/UTF(Optimistic Concurrence Control with Update Transaction First) that is most appropriate for broadcast environment. OCC/UTF lets a query transaction, that has already read the data item which was invalidated by update transaction, read again the same data item without the abort of the query transaction due to non-serializability. Therefore, serializable order is maintained and the query transaction is committed safely regardless of commitment of update transactions. In OCC/UTF, Clients need not require server to commit their query transactions. Because of broadcasting the validation reports including values updated recently to clients, it reduces the overhead of requesting recent values from the server and the server need not also re-broadcast the newest values. As a result, OCC/UTF makes full use of the asymmetric bandwidth. It can also improve transaction throughput by increasing the commit ratio of query transactions as much as possible.

• Journal of the Korea Society of Computer and Information
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• 제17권2호
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• pp.13-21
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• 2012

Mobile data caching is usually used as an effective way to improve the speed of local transaction processing and reduce server load. In mobile database environment, due to its characters - low bandwidth, excessive latency and intermittent network, caching is especially crucial. A lot of mobile data caching strategies have been proposed to handle these problems over the last few years. However, with smart phone widely application these approaches cannot support vast data requirements efficiently. In this paper, to make full use of cache data, lower wireless transmission quantity and raise transaction success rate, we design a new mobile data caching synchronization strategy based on in-demand and replacement priority. We experimentally verify that our techniques significantly reduce quantity of wireless transmission and improve transaction success rate, especially when mobile client request a large amount of data.

• Convergence Security Journal
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• 제10권2호
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• pp.51-57
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• 2010

This paper proposes extended trust evaluation mechanism which is able to become the standard of the node selection which provides a better service by using the basic transaction message which occurs from within the mobile Ad-hoc network and the additional transaction message and add confidence value. Furthermore, throughout the simulation shows the efficiency of the proposed trust evaluation mechanism.

• International journal of advanced smart convergence
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• 제6권1호
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• pp.1-8
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• 2017

Diverse types of malicious code such as evasive Server-side Polymorphic are developed and distributed in third party open markets. The suspicious new type of polymorphic malware has the ability to actively change and morph its internal data dynamically. As a result, it is very hard to detect this type of suspicious transaction as an evidence of Server-side polymorphic mobile malware because its C&C server was shut downed or an IP address of remote controlling C&C server was changed irregularly. Therefore, we implemented Simulated C&C Server to aggregate activated events perfectly from various Server-side polymorphic mobile malware. Using proposed Simulated C&C Server, we can proof completely and classify veiled server-side polymorphic malicious code more clearly.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제22권51호
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• pp.139-149
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• 1999

Developed in this paper is a prototype extranet using mobile device such as Personal Digital Assistance(PDA) or Handheld PC(HPC). Especially an adjustment transaction system for auto insurance using wireless data communications is described. Using infrastructures such as PCS, Cellular, Private Radio, wireless communications offers tremendous applications in Korea. A survey of such applications is presented in this paper. Also an analysis of currently available infrastructures of wireless communications is described in this paper. The scheme of an adjustment transaction consists of seven steps: (1) get list of adjustment, (2) obtain insurance information, (3) check police record, (4) get an accident record, (5) get bluebook value, (6) examine the car, (7) file report. Comparing with the previous on-line method that spends much time on gathering data, the proposed system guarantees more rapid transaction using wireless communications.

• Journal of Information Technology Services
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• 제13권4호
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• pp.245-254
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• 2014

Payment system is defined as the various contracts and operating facilities for the transfer of monetary value to clear the relationship between credit and debt. Payment systems essentially require the efficient and reliable operations. Card-based payment systems are developed practically and creatively in accordance with the progress of ICT. Especially in mobile environment with intelligent mobile devices such as smart-phones and tablets, a variety of payment services are provided. Existing card-based payment services are configured by the payment transaction initiated by the merchants card acceptance and then swiping into the CAT (Card Authorization Terminal) to begin the transaction. The merchant initiated payment services are now applied to the Wireless CAT (W-CAT) for mobile environment. That kind of payment services cause many problems such the illegal card information leaks and the lingering threat of W-CAT theft. Also, the use of many W-CATs increased cost to the merchant. In this paper, we propose the card holder initiated card payment system using the intelligent mobile devices in mobile environment for solving problems of the existing merchant initiated card payment system and coping effectively with the activation of a wireless data network and changes of information technology.