• Journal of information and communication convergence engineering
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• v.2 no.2
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• pp.106-109
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• 2004

This study designs a load balancer via direct routing that share a virtual service on a single IP address in the Linux system and suggests an efficient load balancing method to improve transmission speed in the web server cluster environment. It will increase performance and scalability with fast packet transfer and removing bottleneck problem by using TCP Splicing and Content-Aware Distributor method. This method is expected to be the noticeable technology that provides an important interface, which make application services for e-commerce effectively be applied to high-speed network infrastructure. At this time, it is required to study further on the optimum balancing method in the web server cluster environment so as to apply the hybrid (optimum load balancing method by software and hardware) method and improve the reuse of security cession based on high-speed TCP connections.

• Journal of Information Technology Services
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• v.5 no.3
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• pp.165-172
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• 2006

In this paper, we designed a new type of X-internet framework by using Flash component and server service API and analyzed its performance. Proposed X-internet framework uses Flash MX Professional 2004, Java, and software which opened middleware and database. Since proposed framework use the server service API that we developed in this paper and Flash player, this framework does not need server module. Proposed framework enables to obtain design with dynamic user interface compare to Web application and enables to reduce development time. In analytical results, it has been shown that proposed x-internet framework have efficient characteristics such as network traffic, low development cost and dynamic user interface implementation. Since proposed X-internet framework can operate in environment of current developer friendly, it is useful for development of various new application programs and we confirm it through Flash web mail implementation by using proposed x-internet framework.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.293-298
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• 2001

This paper propose the DoubleQ web server that classifies incoming requests according to whether the requested document is cached or not. Requests that demand a cached document is put into the Service Queue while other requests are added to the Defer Queue. The DoubleQ web server services requests that are in the Service Queue before it services requests in the Defer Queue. This strategy is used to reduce disk accesses that have been the predominant overhead of traditional web servers. Experimental results using synthetic data show that improvements in the average user response time and the throughput of the web server may be achieved.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.2
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• pp.95-102
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• 2011

In this paper, a Mobile Continuous Query Processing System (MCQPS) is designed to solve problems related to database hoarding, maintenance of shared data consistency, and optimization of logging. These problems are caused by weak connectivity and disconnection of wireless networks inherent in mobile database systems under mobile client-server environments. We show the superiority of the proposed MCQPS by comparing its performance to the Client-Intercept-Server (C-I-S) model. In addition, several experimental results show the effectiveness of our proposed indexing structure and methodology for real-time continuous queries.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.7
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• pp.283-292
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• 2013

In order to ensure high performance, all the servers in an existing server cluster are always On regardless of number of real-time requests. They ensure QoS, but waste server power if some of them are idle. To save energy consumed by servers, the server power mode control was developed by shutdowning a server when a server is not needed. There are two types of server power mode control depending on when a server is actually turned off if the server is selected to be off: static or dynamic. In a static mode, the server power is actually turned off after a fixed time delay from the time of the server selection. In a dynamic mode, server power is actually turned off if all the services served in the server are done. This corresponds to a turn off after a variable time delay. The static mdoe has disadvantages. It takes much time to find an optimal shutdown time manually through repeated experiments. In this paper, we propose a dynamic shutdown method to overcome the disadvantages of static shutdown. The proposed method allows to guarantee user QoS with good power-saving because it automatically approaches an optimal shutdown time. We performed experiments using 30 PCs cluster. Experimental results show that the proposed dynamic shutdown method is almost same as the best static shutdown in terms of power saving, but better than the best static shutdown in terms of QoS.

• Journal of the Korea Society of Computer and Information
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• v.16 no.5
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• pp.79-91
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• 2011

In this paper, a DS (Data Synchronization) server for mobile communication environments is constructed and the suitability and the performance of its operations are validated. The DS server provides a way to update the newest data and keep data consistency for clients (mobile devices). In addition, the DS server constructed in this paper supports various synchronization types, and detects all changes and conflicts. In case of data conflicts, the DS server resolves the conflicts according to the several policies implemented in this work. The DS server conforms to the OMA(Open Mobile Alliance) DS standard protocol for interoperability with other mobile devices and servers. In addition to the transmission-by record scheme proposed by the OMA DS standard protocol, the DS server constructed in this paper also provides the transmission-by field scheme for the enhancement transmission performance between the server and clients. In order to validate its operations, data synchronization between the DS server and the SCTS (SyncML Conformance Test Suit), the suitability validation tool provided by the OMA, is performed. The validation results show that the DS server constructed in this paper satisfies all of the test cases except the Large Object function. The Large Object function will be implemented later because the function is not needed for the personal information synchronization process which this paper aims for. Also, synchronization times of the DS server are measured while increasing the number of data and clients. The results of the performance evaluations demonstrate that the DS server is scalable, in the sense that it has not suffered from any serious bottlenecks with respect to the number of data and clients. We expect that this work will provide a framework for various studies in the future for improving mobile DS operations.

• Journal of Korean Society for Quality Management
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• v.45 no.4
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• pp.933-942
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• 2017

Purpose: The purpose of this paper is to evaluate the performance quality of the open source DBMSs. Performance quality is defined as processing time for Join queries. Query processing time is measured and compared in the most widely used open source DBMSs and commercial DBMS. Methods: By varying the number of tuples of two relations to be joined, the average processing time(seconds) of a Join query in each DBMS was obtained experimentally. ANOVA and Tukey HSD test were used in order to compare the performance quality of DBMSs. Results: There was a significant difference between the performance qualities of the three DBMSs at all experimental levels where the number of tuples was 100, 1,000, 2,000, 10,000, and 50,000. As a result of the Tukey HSD test, two open source DBMSs (MariaDB, MySQL) were classified in the same group only at the tuple level of 100. The commercial DBMS (MS-SQL Server) belonged to another group. At level of more than 1,000 tuples, all three DBMSs belonged to different groups. Conclusion: Within the open source DBMS group, MariaDB showed the better performance quality except for a small number of tuples. Thus the results show that MariaDB can be the alternative to MySQL which is currently most widely used. Between open source DBMS and commercial DBMS groups, MS-SQL Server always shows the best performance quality, but the less number of tuples, the less the difference.

• 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.

• Convergence Security Journal
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• v.13 no.3
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• pp.17-23
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• 2013

Clustering is required to configure clustering interdependent structural technology. Clustering handles variable workloads or impede continuity of service to continue operating in the event of a failure. Long as high-availability clustering feature focuses on server operating systems. Active-standby state of two systems when the active server fails, all services are running on the standby server, it takes the service. This function switching or switchover is called failover. Long as high-availability clustering feature focuses on server operating systems. The cluster node that is running on multiple systems and services have to duplicate each other so you can keep track of. In the event of a node failure within a few seconds the second node, the node shall perform the duties broken. Structure for high-availability clustering efficiency should be measured. System performance of infrastructure systems performance, latency, response time, CPU load factor(CPU utilization), CPU processes on the system (system process) channels are represented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.608-617
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• 2011

ubiquitous network management system (u-NMS) is the network management system based on smartphone which are recently of wide use. The purpose of the u-NMS is to provide convenience for network administrator utilizing the mobility of smartphone and to manage the network efficiently. This paper proposes the smart NMS agent and the mobility management server (MMS). The smart NMS agent enables to use the monitoring web server and remote control application on the smartphone in wireless network. The MMS is developed to reduce the problems such as handover latency and packet loss, which can be taken place in wireless network. The network manager can monitor traffic in real time through the smart NMS agent and remotely control the network efficiently when sudden failures happen in the u-NMS. In this paper, performance evaluation is carried out with our test-bed system implemented. We focus on the measurement of the MMS performance. When the MMS is compared to previous mobility management protocol, our mobility management server reduces the average latency up to 65% in initial access, handover latency and processing delay to the network management center.