• Journal of KIISE:Computer Systems and Theory
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• v.32 no.1
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• pp.21-28
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• 2005

Web servers or web application servers, in general, adopt multi-thread model for efficient handling of many user requests. However, the multi -thread model always does not show the better performance than multi -process model. Sometimes, in a certain specific case, it can show worse performance than multi -process model. In this paper, to trace the cause of the decreased performance of multi -thread model, we experiment and analyze the performance of the multi-thread model by using two approaches. At first, we compare the performance of the multi-process model and multi-thread model for various application environments. Second, we observe the effects of variations of web server's dynamic directives, which are used to increase the flexibility of the web server for various system environments. For the experiments, we integrated a web client simulator, which was written by us, with the Apache 2.0 web server. This paper shows and analyze the results of the experiments.

• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.32-39
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• 2007

An important application domain for online services is an interactive, multi-player game. In recent, many increase of users that use on-line services through networks have caused a heavy load to the server. In this paper, we propose a MMORPG(Massively Multi-player Online Role Playing Game) distributed game server using flayer-Cell. Our method provides efficient solution of a MMORPG distributed game server for large numbers of users. It is shown through the experiments that our method outperforms existing methods in terms of memory utilization rate and processing speed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.833-838
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• 2014

Recently the use router is to allow multiple computers by one IP can be connect to the Internet. Also, the PC or server in order to use a Web server or a print server, Web Hard, P2P should be settings. In this paper, we are building a multi-functional Web server that using a router supported OpenWRT based on network settings and firewall settings and a variety of services. A web server can be provided the Internet phone and secure multimedia service Web server router based OpenWRT may be provided through a mobile app and the PC application service.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.6
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• pp.329-335
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• 2018

Offline-first strategy is that it allows data to be saved while offline, and when connected online, data is synchronized to ensure that all devices have the same data. Multi-device is a term that shares data through synchronization on various platforms on Android, ios, etc. First, all of the data is stored in the local repository like SQLite and then on the server via HTTP communication. Then, the synchronization is completed by receiving the changed data from the server and storing it in the local repository at the time of the synchronization, and sending the changes to the server from the client. We proposed and implemented a database structure, APIs, and a illustrative application running on PC and Android phone.

• Journal of the military operations research society of Korea
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• v.23 no.2
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• pp.25-44
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• 1997

Internet users been rapidly increased due to the convenient GUI environment. Current Web-based HTTP/CGI client/server architecture has several problems such as the CGI bottleneck, no maintaince of state, and no load balancing. However, with Java and CORBA technologies called“Object Web technology”, we can solve them because Java is not only a mobile code but also a platform-independent code, and CORBA has ability to build distributed object and language-independent object model. The goal of “Object Web technology”is to create multivendor, multiOS, multilanguage“legoware”using objects. This paper implement“Book Search System”which is Web-based client/server architecture using distributed objects. Environments of this implementation are Hangul Windows NT(included IIS) server, Hangul Windows 95 client, Visigenic's VisiBroker for Java 1.2 which is a product of CORBA 2.0, HTTP protocol on TCP-IP-based, Sybase SQL Anywhere 5.0 database server, and the interface between application server and database is JDBC-ODBC bridge middleware.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.5
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• pp.712-717
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• 2007

Using home network system including home server, home service robot, a variety of device, it is generally known that application of Multi Agent System for performing variously distributed process that can be occur in home environment, is efficient method. In this system, it is intelligent service robot that a key of human interface and physical service offer Therefore, using application of established multi agent system, we can defined Multi Agent Robot System. In 'open' home environment, between all agent data interaction and cooperation are needed for Multi Agent System offer to user that more efficient service. For this, we focus our attention on define as agent that can autonomic drive and offer to user that physical service robots and, design, suggest the simulator can display that between robot agents communication or between other agents, like home server, and robot agents communication information to user interface.

• Journal of Korea Multimedia Society
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• v.9 no.6
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• pp.742-749
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• 2006

In the network-based game where it uses the Internet infrastructure, the implementation is possible with the various methods. Such Applications are developed in the multi-tired architecture. There are many cases for the server to be separated from the hardware or the software. In this case, a lot of applications make the distributed process possible and are made as the multi-tiered architecture to develop the reusability of the existing software module. Especially, it is mostly general to separate for the case of a database server to a new tier. One of the important points of multi-tiered server side applications is security and because of this, it is difficult to share the related data about the design skill. Using design patterns, it gives help in reusing the existing written-code for the design of the game that needs a lot of money and time. Design Patterns are related to the software reuse. For the development of more efficient games, if well-defined design patterns are provided to the developers, then it would make more easy advanced game API and make possible the framework for the game development based on the API Through the analysis of the general network-based game currently servicing in the Internet, in this paper, we discuss how to implement a business logic tier using database system among the server side architectures. The main objective of this article is to show an efficient APIs(Application Programming Interfaces) design method which can be used to manage the data that must be saved to the database system among the packets that client/server have to be exchange.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.189-192
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• 2006

An important application domain for online services is an interactive, multiplayer game. in recent, many increase of users that use on-line services through networks have caused a heavy load to the server. In this paper, we propose a MMORPG distributed game server using 2Layer-Virtual Cell. Our method provides more effective solution of MMORPG distributed game server for large numbers of users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4347-4366
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• 2015

Distinguished with traditional strategies which offload an application's computation to a single server, parallel computation offloading can promote the performance by simultaneously delivering the computation to multiple computing resources around the mobile terminal. However, due to the variability of communication and computation environments, static application component multi-partitioning algorithms are difficult to maintain the optimality of their solutions in time-varying scenarios, whereas, over-frequent algorithm executions triggered by changes of environments may bring excessive algorithm costs. To this end, an adaptive application component mapping algorithm for parallel computation offloading in variable environments is proposed in this paper, which aims at minimizing computation costs and inter-resource communication costs. It can provide the terminal a suitable solution for the current environment with a low incremental algorithm cost. We represent the application component multi-partitioning problem as a graph mapping model, then convert it into a pathfinding problem. A genetic algorithm enhanced by an elite-based immigrants mechanism is designed to obtain the solution adaptively, which can dynamically adjust the precision of the solution and boost the searching speed as transmission and processing speeds change. Simulation results demonstrate that our algorithm can promote the performance efficiently, and it is superior to the traditional approaches under variable environments to a large extent.

• International Journal of CAD/CAM
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• v.3 no.1_2
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• pp.51-60
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• 2003

The growth of the World Wide Web and the advances in high-speed network access have greatly changed existing CAD/CAE environment. The WWW has enabled us to share various distributed product data and to collaborate in the design process. An international standard for the product model data, STEP, and a standard for the distributed object technology, CORBA, are very important technological components for the interoperability in the advanced design and manufacturing environment. These two technologies provide background for the sharing of product data and the integration of applications on the network. This paper describes a distributed CAD/CAE environment that is integrated on the network by CORBA and product model data standard STEP. Several prototype application modules were implemented to verify the proposed concept and the test result is discussed. Finite element analysis server are further distributed into several frontal servers for the implementation of distributed parallel solution of finite element system equations. Distributed computation of analysis server is also implemented by using CORBA for the generalization of the proposed method.