• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.459-464
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• 2005

The online game system could be largely divided into two parts: servers and clients. Clients accesses to a game server and analyzes the packets transmitted from a server. A game server manages users information and database. U a game server allows a new client to access the server to execute a game, it should accept the access request of the new client maintaining the online connection of the existing users. In this paper, we compare Process method and Thread method within the multiple jobs process methods of a server. Then we propose an asymmetric distributed multi server architecture that is adequate to asymmetric distributed architecture that is widely applied to most game servers. The proposed asymmetric distributed multi server architecture includes login server, game server, communication server and database server to perform its own feature independently. Comparing its other architectures, it shows better performance economically and technically. Especially it improves the stability and expandability of a server.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.272-275
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• 2003

This paper presents the role and its function of Tool server. MPEG-21 means multimedia framework for delivery and consumption of multimedia which is being discussed in ISO/IEC 21000. A view of MPEC-21 aims to define multimedia framework to enable transparent use of multimedia resource across a wide range of networks and devices used by different communities. MPEG-21 will enable all-electronic creation delivery and trade of digital multimedia content and transparent usage of various content types on network device. Therefore, we can provide access to information and services from almost anywhere at anytime with various terminals and networks. In order to support multimedia delivery chain that contains content creation, production, delivery and consumption, we need many standards(elements) for identify, describe, manage and protect the content. Thus, we define Digital Item Player(DIP), Digital Item Adaptation(DIA) server and Tool server as primary objects of MPEG-21 multimedia framework. DIP provides a function which creates and consumes Digital Item(DI) as a kind of a digital object by user. A DI contains both media resources and metadata including rights information. DIA server deals with the usage environment description schema of the user characteristics, terminal and network characteristics and natural environments. DIA server adapts the original DI to the usage environment description sent from the terminal and transmits the adapted DI to the terminal. Tool server searches for a tool requested from DIP or DIA and downloads the best tool to DIP or DIA server. In this paper, we present how Tool sewer is organized and is used among 2 primary objects. The paper is structured as followings: Section 1 briefly describes why MPEG-21 is needed and what MPEG-21 wants. We see requirement that tool server must equip functionally in section 2. The proposed tool server,its structure and its functionality are presented in section 3. Section 4 explains a scenario that tool server transmits tool to DIP and shows the experimental result. The paper concludes in section 5.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.4
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• pp.216-223
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• 2013

As the fast growth of using Internet, the requests of clients having different types and pressing loads on the server have been increased in World Wide Web. Thus the interesting issue is how to measure the real capacity of a Web Server. There have been much recent studies about measuring the capacity of web server. But the cause of Server response time delay is not just server itself but also network packet loss. To measure the practical capacity of web server, we generate scalable clients using Posix Thread, transport packets which were generated by scalable clients to the server using UDP and receive the packets which were the remain packet from network packet loss using TCP. In this paper, we propose a method to measure the practical capacity of a web server using the Scalable Clients based on Posix Thread and the transport on Application level.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.645-648
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• 2007

This paper describes database server management system by mobile device. Our system can control database server immediately in any where by mobile device. We have developed the dataset server CE which interface with mobile device, database management system which rons in mobile device and web services which connect the mobile database with desktop database. External mobile device communicate with web service agent via wireless equipment. Our system includes dataset server CE client engine, web service server agent and mobile device management system. Through the test by an application program, we have confirmed that our system operates very well each others.

• Journal of Korea Multimedia Society
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• v.17 no.4
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• pp.526-534
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• 2014

Most of the multiplayer games available online are based on a client-server architecture because this architecture gives better administration control to the game providers than peer-to-peer architecture. In this architecture, the server is responsible for all the communication between the connected clients. The weakness of this architecture is its bandwidth requirement and scalability. Peer-to-peer architectures have then been proposed to solve these issues. In this paper, we propose a hybrid client-server architecture in which the game state is partially shared by the mobile terminal to achieve consistency among different players. Like a peer-to-peer architecture, this architecture uses client-side capacities to reduce bandwidth requirements for the server and improves consistency in wireless networks. Client events have different timeliness and consistency requirements according to their nature in the game world. These requirements lead to tasks with different priorities on CPU processing. In the proposed architecture, either the server or the client applies consistency mechanism according to the priority level. Simulation experiments show that the bandwidth of the server in this architecture is smaller than that of the client-server architecture. As a result, the server in the proposed architecture can accommodate more clients with enhancing the scalability.

• International journal of advanced smart convergence
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• v.5 no.4
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• pp.26-31
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• 2016

In a cloud computing environment, a cryptographic service allows an information owner to encrypt the information and send it to a cloud server as well as to receive and decode encrypted data from the server which guarantees the confidentiality of shared information. However, if an attacker gains a coded data and has access to an encryption key via cloud server, then the server will be unable to prevent data leaks by a cloud service provider. In this paper, we proposed a key management server which does not allow an attacker to access to a coded key of the owners and prevents data leaks by a cloud service provider. A key management server provides a service where a server receives a coded public key of an information user from an owner and delivers a coded key to a user. Using a key management server proposed in this paper, we validated that the server can secure the confidentiality of an encryption key of data owners and efficiently distribute keys to data users.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.329-332
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• 2005

In order to provide the reliable service and contents to telematics service user, any service server must be tested and verified before launching its service in sufficient. In this paper, we proposed a test framework for telematics server. The proposed framework includes conformance test of server, interoperability test between telematics service server and telematics terminal. The framework proposed the concept and test model for two categories of testing.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.2
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• pp.131-142
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• 2005

This paper proposes queueing models for a Web server system which is composed of an infinite-buffer main server and finite-buffer auxiliary server(s). The system is modeled by the level-dependent quasi-birth- death (QBD) process. Utilizing the special structure of the QBD, we convert the infinite level-dependent QBD into a finite level-independent QBD and compute the state probabilities. We then explore the operational characteristics of the proposed web-server models and draw some useful conclusions.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.30-31
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• 2012

본 논문에서는 Android System 핵심 부분을 기존의 System Server 에 Application Server 를 더하여 2개의 서버로 재구성하는 방안을 논의한다. Application Server 는 DalvikVM 과 Application 저장/스케줄링 프로세스로 구성한다. Application Server 가 모든 사용자의 Application 을 저장하고 스케줄링하고 DalvikVM에 할당하여 실행시키도록 한다. 이 방법은 사용자 입장에서는 단순화된 Android System 구조로 인하여 응용의 개발이 용이해지고 응용의 반응도 빠르게 된다. 시스템 입장에서도 구조가 단순해져서 실행 효율이 좋아지고 메모리 사용 효율도 좋아진다.

• 한국정보통신설비학회:학술대회논문집
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• 2003.08a
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• pp.229-233
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• 2003

최근, 인터넷 사용자가 급증하면서 빠른 서비스에 대한 문제가 큰 관심이 되고있다. 특히 데이터베이스 시스템에서 저장 삭세 수정 등은 사용자에게 긴 대기시간을 요구할 수도 있기 때문에 사용자의 불평을 야기할 수 있다. 이 논문에서는 3-티어 방식에서 요즘 많이 사용되는 application server의 cache에 대해서 말하고자 한다. 기존 application server는 데이터를 application server cache에 저장하여 같은 데이터를 서비스할 경우 server의 cache를 사용하지만 이 논문에서 제안하는 것은 접속된 client를 관리하여 각각의 client에 cache를 만들고 application server나 또는 데이터베이스 server가 서비스를 하지 못할 경우는 가장 최근의 데이터를 가지고 있는 client를 찾아 client cache에 있는 데이터를 서비스 하자는 것이다.