• The Transactions of the Korea Information Processing Society
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• v.7 no.3
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• pp.799-807
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• 2000

In this paper, object replication Client/server under distributed computing system is design and implementation. Today many end-users have a computer communication by using internet in the distributed system of client/server. If many users request services to a specific remote server, the server should have got a overhead for hat service processing, delayed the speed for replay, and bring a bottleneck in communication network. Therefore object replication method was proposed to solve this problems. The growth of internet works and distributed applications has increased the need for large scale replicated systems. However, existing replication protocols do not address scale and autonomy issues adequately. Further, current application protocol require consistency of different levels, and therefore should be the selection function of consistency in them, in order to have particular semantics of each level. In this paper, server overhead and bottleneck happening in remote procedure call be using server object replication. Therefore access transparency can be improved by sharing object duplicately. So it will Keep up with the consistency within the replicated objects.

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

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.668-685
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• 2019

Provision of higher throughput without sacrificing consistency guarantees in replication systems is a critical problem. In this paper, we propose a novel approach called Bidirectional Chain Replication (BCR) to improve throughput in traditional Chain Replication (CR) through better utilization of computing and communication resources of the chain. Unlike CR where the whole replicated data store is treated as a single unit, in BCR the replicated shared data at each server in the chain is split into two disjoint Logical Partitions ($LP_1$, $LP_2$). This forms two chains running concurrently on the same hardware in two opposite directions; the first chain ($CR_1$) exclusively manipulates data objects in $LP_1$, while the second chain ($CR_2$) exclusively manipulates data objects in $LP_2$, therefore, conflict is avoided and concurrency is guaranteed. The simultaneous employment of these two chains results in better utilization of hardware in the sense that the two chains can evenly share the workload, hence, throughput can be improved without sacrificing consistency. Experimental results showed an improvement of approximately 85% in throughput of BCR over CR.

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

• Journal of Internet Computing and Services
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• v.4 no.6
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• pp.87-93
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• 2003

Data Replication makes distributed system and database system improved in availability and performance. But it is difficult to keep strict consistency in data update. Existing algorithms keep strict consistency, but have problems of cost a great deal and delay time. It is to introduce hybrid update propagation algorithm which permits eager update for original copy and propagates lazy update for other copies. Hybrid update propagation algorithm also permits group update in ownership. This algorithm menages replica version in order to control group update consistency. Consistency and performance is improved by combining eager update and lazy update with group ownership. Simulation shows improvement of transaction throughput and response time depending on application and execution environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.91-99
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• 2014

The main game architectures for multiplayer online games are the traditional client-server architectures, multi-server architectures and P2P(peer-to-peer) architectures. P2P architectures, due to their distributed and collaborative nature, have low infrastructure costs and can achieve high scalability as well as fast response time by creating direct connections between players. However, P2P architectures face many challenges. Distributing a game among peers makes maintaining control over the game more complex. These architectures also tend to be vulnerable to churn and cheating. Providing consistency control in P2P systems is also more difficult since conflicting updates might be executed at different sites resulting in inconsistency. In order to avoid or correct inconsistencies, most multiplayer games use a primary-copy replication approach where any update to the object has to be first performed on the primary copy. This paper presents the primary-copy model with the update dissemination mechanism that provides consistency control over an object in P2P architectures for multiplayer online games. The performance for this model is evaluated through simulation experiments and analysis.

• Journal of Internet Computing and Services
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• v.6 no.1
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• pp.73-84
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• 2005

ALTIBASE/sup TM/ is the relational main-memory DBMS in which a main memory is primarily used as the main storage device. We present the database replication strategies and techniques of the ALTIBASETM system in order to meet the requirement of high availability and efficient transaction processing. Our process architecture for replication management and its communication model are proposed, and database replication protocols are also described. We show the experimental result of transaction processing rate with various DBMS parameters and overall performance of database replication system as compared to standalone system.

• Journal of Internet Computing and Services
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• v.2 no.5
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• pp.71-79
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• 2001

Replication in distributed databases is to improve efficiency, availability, and autonomy, But applying the strict consistency in real systems is very difficult. In this paper, I introduce a hybrid protocol permitting group update through eager update propagation and weakening consistency through lazy update, This protocol manages replica version number for the group update consistency and generates partially ordered replica spanning tree for the serializability of lazy update transactions. It preserves weak consistency by combining synchronous and asynchronous update mechanism. Study of performance analysis for the efficiency of the protocol be included in next paper.

• The KIPS Transactions:PartD
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• v.10D no.4
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• pp.647-654
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• 2003

The replication of data is used to increase its availability and to improve the performance of a system. The distributed database system has to maintain both the database consistency and the replica consistency. This paper proposes an algorithm which resolves the conflict of the operations by using the mechanism based on the structure that the replicas of each data item are hierarchically organized. Each update is propagated along the tree based on the fact that the root of each data item is the primary replica in partially replicated databases. The use of a hierarchy of data may eliminate useless propagation since the propagation can be done only to sites having the replicas. In consequence, the propagation delay of updates may be reduced. By using the timestamp and a compensating transaction, our algorithm resolves the non-serializability problem caused by the conflict of operations that can happen on the way of the update propagation due to the lazy propagation. This resolution also guarantees the data consistency.

• Journal of Internet Computing and Services
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• v.17 no.4
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• pp.1-9
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• 2016

Algorithms implementing distributed shared memory (DSM) were developed for ensuring consistency. The performance of DSM algorithms is dependent on system and usage parameters. However, ensuring these algorithms to tolerate faults is a problem that needs to be researched. In this study, we proposed fault-tolerant scheme for DSM system and analyzed reliability and fault-tolerant overhead. Using our analysis, we can choose a proper algorithm for DSM on error prone environment.