• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.38-46
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• 2010

A stable game managing system is absolutely needed to accept simultaneous interlacing of many users for on- line game system. The proposed P2P on-line game system in this paper is able to get stable and real-time game managing within limited time stamp utilizing through reorganizing peers according to synchronous time which can be avoid congestion on one region, it is possible to synchronize for game nodes within limited time stamp utilizing. Reorganizing M-tree which leads 10 distribute loads. The system manages each region unit, and it is execute no matter how big game sizes are. Thus to ensure such as the problems of expand server and stabilization or message transmission. Also, prove efficiency of the suggested system through the simulation.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.21-25
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• 2009

The results of a recent case study for material characterizations and structural evaluation to design asphalt overlay thickness of William P Hobby airport in Houston, Texas are presented herein. The existing runway 12R-30L of Hobby airport consisted of thick asphalt overlay over Portland Cement Concrete (PCC) and the localized surface shoving as evident in the closure of surface groove has been observed recently. Using the field cored asphalt concrete mixtures, measurements of percent air voids, asphalt content and aggregate gradation were conducted to find out the causations of surface shoving and groove closure. The FAA layered elastic program, LEDFAA was utilized to evaluate pavement structural conditions for new asphalt overlay. Two different composition assumptions for existing pavement were made to evaluate the pavement as followings: 1) APC, Asphalt Concrete Overlay over PCC pavement and 2) AC, Asphalt Concrete pavement. Based on laboratory testing results, a ratio of percent passing #200 to asphalt content ranged 1.1 to 2.2, which is considered a high ratio and a tendency of tender mix design was observed. Thus, the localized surface shoving and groove closure of the runway 12R-30L could be attributed to the use of excessive fine contents and tender mix design. Based on the structural evaluation results, it was ascertained that the analysis assuming the pavement structure as AC pavement gives more realistic structural life when the asphalt overlay is thicker enough compared to PCC layer because the existing PCC pavement under asphalt overlay acts more like a high quality base material.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.6
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• pp.430-434
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• 2009

In this paper, we propose an efficient content sharing scheme for structured P2P overlay network. The main idea of this paper is to exploit the identified routing table instead of anonymous one using social relationships among nodes. The contribution of this paper is to present a means of mitigating the problem of 'free riding' and the threat of misrouting attack by malicious nodes.

• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.245-256
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• 2009

Pastry overlay network is one of structured P2Ps using DHT(Distributed Hash Table). To reduce the number of messages among nodes, Rosary and LAR have been proposed by exploiting spatial locality and caching, respectively, in the Pastry. Rosary consists of Inter-Pastry and Intra-Pastry. A root node is assigned as a representative in each Intra-Pastry and it has the responsibility of Inter-Pastry and Intra-Pastry routing. Therefore, Rosary has several disadvantages; 1) low fault tolerance in case of root node failure 2) routing hop count increases because of the use of root nodes compared to the existing structured P2Ps, and 3) the communication load is concentrated in some specific areas. LAR has inefficient problems in that caching is not distributed among nodes in Intra-Pastry and caching is used by only nodes in the Intra-Pastry. In this paper, we propose an improved Pastry called Doughnut to overcome the above problems of Rosary and LAR. By dividing nodes with the local characteristics, the Doughnut consists of Inter-Pastry and Intra-Pastry, and all nodes have the responsibility of Inter-Pastry and Intra-Pastry routing. This results in that all nodes perform the role of the existing root node. This solves the problems of the reducing of fault-tolerance, the increasing of routing hop count, and the not-distributed communication load. Also Doughnut can use cache effectively because it guarantees the even cache distribution in local(Intra-Pastry) and the cache contents in local can be used in the other local. The proposed algorithm is implemented using simulator and the experimental results show the effectiveness of the proposed method compared to the existing method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.211-216
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• 2011

Networked virtual environments (NVEs) are distributed systems where geographically dispersed users interact with each other in virtual worlds by exchanging network messages. Massively Multiplayer Online Game (MMOG) is one of diverse applications where more than hundreds of users enjoy experiencing virtual worlds. A limited area called area of interest (AOI) in MMOG is reduced the load caused by message exchange between users. Voronoi-based Overlay Network (VON) is proposed to reduce the bandwidth consumption in P2P environments and Vorocast also is made using message forwarding in VON. We propose a dynamic AOI management method that solves problems such as a consistency and latency due to forwarding position updates to neighbor nodes from the message originator in forwarding scheme. Our scheme provides the consistency and reduces latency by combining direct connection scheme and Vorocast scheme compared to existing schemes. The communication between a user and users existing in center circle within AOI of the user is directly connected and the communication between the user and users existing outside the center area within AOI is using Vorocast scheme. The proposed model is evaluated through simulations.

• The KIPS Transactions:PartC
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• v.18C no.1
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• pp.51-60
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• 2011

In this paper, we propose a P4P based P2P system for live multimedia streaming services. In order to satisfy the strict requirement of delay in live multimedia streaming, in the proposed scheme, the P4P server of network provider provides the network status information related to delay and congestion links to P2P system in addition to the information to optimize the network resource utilization. The P2P system server, then, makes the peering suggestion based on the information from the network server. Also, we propose a playback synchronization mechanism that enable each peer to start the playback within the limited variation from the playback positions of source peer. Through the simulation results, it is shown that the proposed scheme not only deals with the original objective of the P4P framework, i.e., effective network utilization, but also the live multimedia streaming requirements. It enhances the playback continuity, and reduces the playback start-up latency and the control overhead. In addition, the proposed scheme reduces the variation in playback positions of the peers.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.266-271
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• 2010

최근 MMORPG 게임이나 가상현실 게임들은 대규모의 사용자가 가상세계에 접속하여 게임을 즐긴다. 이러한 환경에서 서버-클라이언트 모델은 서버에 많은 부하를 가져오게 되어, 게임 서비스의 QoS에 나쁜 영향을 준다. 이러한 방법을 해결하기 위해서 서버를 증설 할 수 있으나, 비용이 많이 들기 때문에 최근에 P2P 모델로 구현하려는 시도가 늘고 있다. 하지만 P2P 모델로 구현할 경우 서버의 부하는 쉽게 해결할 수 있으나, 데이터의 동기화에 문제가 생겨서 게임을 아예 진행할 수 없게 되거나, 사용자간의 잘못된 P2P망 구성으로 인해 서버-클라이언트 모델보다 안정적이지 못하다는 문제 점이 있다. 이 논문에서는 기존의 P2P 기법을 통한 영역 분할에 대해 살펴보고, 새로운 영혁 분할 기법을 제안하려고 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.875-878
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• 2010

IPTV 서비스와 함께 홈 채널 서비스가 제공되면 개인이 프로슈머의 입장에서 콘텐츠를 생산 및 소비할 수 있게 된다. 서비스 오버레이 네트워크에서 개인화된 콘텐츠를 이용하고자 하는 개인 이용자들을 묶어서 하나의 가상 그룹으로 형성하고 개인화된 콘텐츠를 송신, 수신 할 때 서비스 오버레이 네트워크에서는 개인화된 콘텐츠의 송신, 수신을 위해 P2P 를 지원한다. 서비스 오버레이 네트워크에서 지원하는 P2P 는 이용자 환경, 상황, 네트워크 상황 등을 능동적으로 인지하여 개인 혹은 다수에게 개인화된 콘텐츠를 전달 할 수 있어야 한다. 따라서 능동적으로 서비스 오버레이 네트워크가 형성될 때 개인이 콘텐츠를 공유, 소비하기 위해 개인 혹은 다수에게 개인화된 콘텐츠를 전달하기 위한 P2P 멀티캐스트 구조를 제안 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.116-119
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• 2009

In this paper, a P2P streaming system for community TV service which requires realtime interactions was designed and implemented. The proposed system constructs a short delay tree-based P2P network in order to effectively support various community TV services within end-to-end delay bounds. Because a community service based on conversation requires a short delay. The P2P network of this paper was constructed by using an algorithm which utilizes locality and delay information. The implemented P2P streaming system is composed of a Web server and a application, each of which was implemented using Asp.Net and C#.Net respectively.

• Journal of Information Processing Systems
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• v.3 no.1
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• pp.8-15
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• 2007

Grid environments provide the mechanism to share heterogeneous resources among nodes. Because of the similarity between grid environments and P2P networks, the structures of P2P networks can be adapted to enhance scalability and efficiency in deployment and to search for services. In this paper, we present a membership management based on a hierarchical ring which constructs P2P-like Grid environments. The proposed approach uses only a limited number of connections, reducing communication cost. Also, it only keeps local information for membership, which leads to a further reduction in management cost. This paper analyzes the performance of the approach by simulation and compares it with other approaches.