• Journal of KIISE:Databases
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• v.30 no.5
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• pp.540-551
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• 2003

Recently, several works have been proposed for updating XML documents［l-3] stored in databases. These researches defined update operations and resolved some semantic problems. Because the update operations are usually validated after execution, several conflicts nay occur. For solving these conflicts, XML database systems must be able to validate an update operation immediately according to DTD before the update operation is executed. Furthermore, in many studies for updating, they just validate whole XML documents and can't validate parts of them. If updates are very frequent, validating whole XML documents will cause performance degradation. In this paper, we propose solutions for these two problems. We extract and store DTD information. Then, when an XML document stored in the database is updated, we verifies whether the update is valid or not by using the information. Consequently, XML database systems can always maintain valid XML documents. The validity of update operations is checked immediately before the actual update operation is applied to the database and the validation is performed on only updated parts of an XML document in the database.

• International Journal of Contents
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• v.10 no.1
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• pp.62-67
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• 2014

Usually, cloud storage systems are developed based on DFS (Distributed File System) for scalability and reliability reasons. DFSs are designed to improve throughput than IO response time, and therefore, they are appropriate for batch processing jobs. Recently, cloud storage systems have been used for update intensive applications such as OLTP and so on. However, in DFSs, in-place update operations are not carefully considered. Therefore, when updates are frequent, I/O performance of DFSs are degraded significantly. DFSs with RAID techniques have been proposed to improve their performance and reliability. Their performance degradation caused by frequent update operations can be more significant. In this paper, we propose an in-place update method for DFS RAID exploiting a differential logging technique. The proposed method reduces the I/O costs, network traffic and XOR operation costs for RAID. We demonstrate the efficiency of our proposed in-place update method through various experiments.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.153-161
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• 2004

An efficient mobility management for mobile stations plays an important role in mobile communication networks. In this paper, we intend to improve the performance of the movement-based location update scheme which is simple to implement and shows good performance. The basic idea used in the proposed location update scheme is to avoid the location update if the mobile subscriber moves around the cell where the last location update was performed. This Is made possible by utilizing the simple movement history information. The performance of the proposed scheme is evaluated and compared with the movement-based location update scheme through simulation. The simulation results show that the proposed location update scheme provides the better performance compared with the movement-based location update scheme by minimizing the unnecessary location updates.

• Journal of KIISE:Databases
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• v.31 no.1
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• pp.39-47
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• 2004

Spatio-temporal databases have been mostly studied in the area of access methods. However, without considering an extraordinary update maintenance overhead after building up a spatio-temporal index, most indexing techniques have focused on fast query processing only. In this paper, we propose an efficient update management method that reduces the number of disk accesses required in order to apply the updates of moving objects to a spatio-temporal index. We consider realistic update patterns that can represent the movements of objects properly. We present a memory based structure that can efficiently maintain a small number of very frequently updating objects. For an experimental environment with realistic update patterns, the number of disk accesses of our method is about 40% lower than that of a general update method of existing spatio-temporal indexes.

• The Journal of Information Systems
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• v.24 no.3
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• pp.75-94
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• 2015

Purpose While new versions of mobile applications could offer users better computing environment, users are not always comfortable with them for various reasons. Considering making update decisions is important task for users, it is crucial for us to understand users' behavior and attitude on app updates. The purpose of this study is to explain why mobile users succumb to both reactance toward the update and satisfaction to the current version, ultimately leading them to feel the regret by employing three theoretical perspectives including regret theory, status quo bias theory and the dual model. Design/methodology/approach Survey data collected from 204 mobile users was used to test the research model using partial least squares analysis. The results have shown that both reactance toward the update and satisfaction to the current version have negative impacts on individuals' decisions to update, which leading to their regret after updating the applications Findings By integrating both status quo bias and regret theory in the model, this study tried to explain why mobile users feel regret in application update settings. More specifically, this study has proposed a novel framework that introduces an individual's update decision on mobile applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.395-403
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• 2011

Various studies were performed for providing the latest spatio-temporal information in mobile GIS Environments. The two-way synchronization scheme collects updated spatio-temporal data in the field and synchronizes with a server by using the wireless network. However, the other mobile terminals have to perform periodically synchronizes with a server. In this paper, we propose the update propagation scheme about spatio-temporal data collected from the mobile terminal. The update propagation scheme does considering various factors where an influence is in the update propagation. Therefore, it provides various update propagation policies according to each factors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.588-591
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• 2009

In ubiquitous computing GIS services, it is possible to use the spatio-temporal data anytime through the mobile device. GIS services regularly update use the latest spatio-temporal data to provide the most suitable services. For this situation, update data is distributed to CD or wired networks update services. However, this method has problem to propagate update data to users as taking long time. In this paper, suggests a synchronization system which propagate update data to users for reducing processing time efficiently. This synchronization system collects update data in the field and synchronizes server with collected data to use mobile devices by real time. For this system, I design and materialize synchronization module which updates update data and wireless network module.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.5
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• pp.25-34
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• 2006

Previous binding update protocols for Mobile IPv6 repeats the same protocol each time a mobile node moves to a foreign link Moreover, mobile nodes repeats the same protocol whenever the lifetime of the current binding update expires. To improve the efficiency of binding updates, we Propose a ticket-based binding update protocol for MIPv6. Our protocol minimizes the binding update cost using a ticket issued by the corresponding node. We have analyzed our protocol security against the security requirements of MIPv6 and existing attacks. Furthermore, we have also compared our protocol against previous binding update protocols.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.85-89
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• 2001

In this paper, we analyze a time-based update method in location management and calculate the optimal time-interval. The probability that an MT is j rings away from the center cell is obtained by computer programming. And using these values, an exact analysis is made for the time-based location management cost. From the result, when the time-based method is applied to location update, we can get the optimal time-interval which minimizes the location management cost.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.3
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• pp.39-46
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• 1994

In this paper, three types of parameter update law which can be used in model reference adaptive control are suggested based on speed-gradient algorithm which was introduced by Fradkov. It is shown that the parameter update law which was proposed by Narendra is a special from of these laws and that proposed parameter update laws can insure the global stability under some conditions such as attainability and convexity. We also comment that the transfer function of reference model shoud be positive real for the realization of parameter update law.