• Journal of KIISE
• /
• v.42 no.1
• /
• pp.7-14
• /
• 2015

Storage Class Memory(SCM) has been considered as a next-generation storage device because it has positive advantages to be used both as a memory and storage. However, there are significant problems of data consistency in recently proposed file systems for SCM such as insufficient data consistency or excessive data consistency-control overhead. This paper proposes a novel data consistency-control scheme, which changes the write mode for log data depending on the modified data ratio in a block, using a rollback-recovery scheme instead of the Write Ahead Logging (WAL) scheme. The proposed scheme reduces the log data size and the synchronization cost for data consistency. In order to evaluate the proposed scheme, we implemented our scheme on a Linux 3.10.2-based system and measured its performance. The experimental results show that our scheme enhances the write throughput by 9 times on average when compared to the legacy data consistency control scheme.

• Journal of Korean Society for Geospatial Information Science
• /
• v.5 no.2 s.10
• /
• pp.193-205
• /
• 1997

It is required for multi-users to share massive mapping data effectively that distributed data model in the Client-Server environment is developed for the replication consistency. The existing model is not effective to the long transaction just like a mapping system, since it does not account lot consistency between GUI screen and database replications even though it emphasizes on the replication consistency. The performance of concurrency control is very important for those long transactions, especially the mapping systems. This model is to support consistency between GUI screen and replicas using display locks. It suggests consistency model improving process performance by modifying memory consistency model and optimistic concurrency control for mapping data's characteristics.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 1999.05a
• /
• pp.91-96
• /
• 1999

Role-Based Access Control(RBAC) is an access control mechanism that reduce the cost of administering access control policies. The Admin Tool developed for RBAC Model manages relationship informations of user and role. In order to maintain the consistency of the information for these relationships, a set of properties defining consistency of the relationship informations is required. When it will be designed security systems applying RBAC policy on the Linux server system environments, this paper described consistency properties of relationship informations for information management of user and role relationships. It leads us to the development of minimal set obtainable the equivalent results of consistency properties for a more efficient Admin Tool implementation.

• Journal of the Korean Home Economics Association
• /
• v.38 no.10
• /
• pp.15-26
• /
• 2000

This study was to investigate cross-situational consistency in copings and copings according to an internal/external locus of control. The subjects were 489 the sixth grade children selected from seven elementary schools in Seoul. The data were analyzed using Pearson's correlation and ANOVA Major findings were that (1) Correlations among corresponding copings across stress situations-such as parents, friend-alienation, friend-conflict, and loaming related stress situations- ranged from r=.27 to r=.67, reflecting cross-situational consistency in copings. (2) Generally, children with an internal locus of control used more active coping behaviors, but used less passive and aggressive coping behaviors than children with an external locus of control in stress situations.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.4
• /
• pp.73-80
• /
• 2016

Multiplayer Online Games(MOG) using the Internet are typically organized based on a CS(client-server) or P2P(peer-to-peer) architecture. We then propose a method that combines a P2P architecture with a CS architecture in order to utilize their advantages. Most MOGs use a primary-copy replication approach that provides strong consistency control over an object. For each object and character there exists an authoritative copy, called primary copy and all other copies are secondary copies or replicas. Any update to the object has to be first performed on the primary copy. In the proposed hybrid architecture, primary copies may reside on the server or be held by clients. In this architecture, load balancing between a server and clients can be achieved by reducing the number of objects maintained by the server. Games consist of various types of actions with different consistency requirements. A multi-level approach to game consistency is sensible as it provides the best trade-off between consistency and performance. The performance for the hybrid game architecture with the primary-copy model is evaluated through simulation experiments and analysis in this paper.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.135-143
• /
• 2015

A Multiplayer Online Game(MOG) is a game capable of supporting hundreds or thousands of players and is mostly played using the Internet. P2P(peer-to-peer) architectures for MOGs can potentially achieve high scalability, low cost, and good performance. The basic idea of many P2P-based games is to distribute the game state among peers and along with it processing, network, and storage tasks. In a primary-copy based replication scheme where any update to the object has to be first performed on the primary copy, this means distributing primary copies of objects among peers. Most multiplayer games use a primary-copy model in order to provide strong consistency control over an object. Games consist of various types of actions that have different levels of sensitivity and can be categorized according to their consistency requirements. With the appropriate consistency level of each action type within a game, this paper allows developers to choose the right trade-off between performance and consistency. The performance for P2P game architecture with the primary-copy model is evaluated through simulation experiments and analysis.

• Journal of Information Technology Applications and Management
• /
• v.17 no.1
• /
• pp.83-105
• /
• 2010

The competence of enterprise for managing information is evaluated not by the amount of information but by the quality of information such as response time, data consistency, and data correctness. The degradation of data quality is usually caused by the inappropriate process of managing the structure and value of stored data. According to the recent survey on the actual condition of data quality management, the correctness and consistency of data appeared to be the most problematic area among the six criteria of data quality management such as correctness, consistency, availability, timeliness, accessibility, and security. Moreover, the problem was more serious in case of small and medium-sized companies than large enterprises. In this paper, therefore, we attempt to propose a new data quality control methodology for small and medium-sized companies that can improve the correctness and consistency of data without consuming too much time and cost. To adopt the proposed methodology to real application immediately, we provided some scripts for as-is analysis and devised automation tools for managing naming rules of vocabulary, terminology, and data code. Additionally, we performed case study on the distribution service of a small-sized company to estimate the applicability of our tool and methodology.

• Journal of KIISE:Databases
• /
• v.30 no.1
• /
• pp.95-107
• /
• 2003

The broadcast environment has asymmetric communication aspect that is typically much greater communication bandwidth available from server to clients than in the opposite direction. In addition, most of mobile computing systems allow mostly read-only transactions from mobile clients for retrieving different types of information such as stock data, traffic information and mews updates. Since previous concurrency 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 the efficient concurrency control for query transaction in broadcast environment. The following requirements are satisfied by adapting weak consistency that is the appropriate correctness criterion of read-only transactions: (1) the mutual consistency of data maintained by the server and read by clients (2) the currency of data read by clients. We also use the serialization graph scheme to check the weak consistency efficiently. As a result, we improved a performance by reducing unnecessary aborts and restarts of read-only transactions caused when global serializability was adopted.

• Journal of KIISE:Databases
• /
• v.29 no.6
• /
• pp.477-491
• /
• 2002

The broadcast environment has asymmetric communication aspect that is typically much greater communication bandwidth available from server to clients than in the opposite direction. In addition, mobile computing systems generate mostly read-only transactions from mobile clients for retrieving different types of information such as stock data, traffic information and news updates. Since previous concurrency 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 optimistic concurrency control based on timestamp interval for broadcast environment. The following requirements are satisfied by adapting weak consistency that is the appropriate correctness criterion of read-only transactions: (1) the mutual consistency of data maintained by the server and read by clients (2) the currency of data read by clients. We also adopt the timestamp Interval protocol to check the weak consistency efficiently. As a result, we improved a performance by reducing unnecessary aborts and restarts of read-only transactions caused when global serializability was adopted.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.985-990
• /
• 2007

This paper presents a novel control algorithm for position control of pneumatic cylinder. Generally, it is difficult to control the pneumatic servo system, due to nonlinearities such as air compressibility, the opening area of the valve, and frictional force between the cylinder and the piston. Especially, it is of significant importance for the control consisten-cy to return the cylinder pressures at equilibrium point to the initial states, still with guaranteeing the continuity of the pressures. For this purpose, the proposed control algorithm makes pressures of both cylinder chambers identical in magnitude but different in direction. The effectiveness and practicability of the control algorithm for the precise position control of the pneumatic cylinder are verified through the simulation study.