• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.5B
• /
• pp.414-426
• /
• 2003

XML is being used to describe components and applications in a vendor and language neutral. Therefore it already has a role in distributed system. XML is also being used as a data interchange format between components and applications in loosely coupled large-scale application. Until now, policy is described for specific applications and devices. Its use has been very limited. In current network management system, we can only invoke predefined operations and actions using policy-based network management. The main motivation for the recent interests in policy-based networks is to support dynamic adaptability of behavior by changing policy without recoding or stopping system. For these reasons we present the use of the XML for describing the policy and PIB(Policy Information Base) in COPS-PR. It improves flexibility and interoperability among heterogeneous network systems. It also can add new functionality into network components. In this paper, we propose a dynamically extensible network management architecture using XML-based PIB.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.6
• /
• pp.79-88
• /
• 2015

In this paper, we examine Ethernet based vehicle network which is recently emerging technology. Current MOST for entertainment will be soon replaced with the emerging Ethernet based vehicle network. Although legacy standard Ethernet has several advantages it is not suitable for vehicle backbone network without any modification. As a result, many researches are happening on extending and modification of the Ethernet function for realtime and reliability. Time-triggered Ethernet, one of many trials known as AS6802, is investigated on the architecture and functionalities. We design the traffic model on Time-triggered Ethernet and analyse the latency of the network. We also consider the QoS requirement and environment of operating configuration for vehicle network.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.1
• /
• pp.176-183
• /
• 2013

This study is focused on analyzing the quality importance of hotel SNS(social network service). And by reviewing precedent papers and references regarding concept and quality factors about SNS in hotel industry, it drew proper criteria to select priorities and evaluate hotel SNS quality using AHP. The important factors based upon related theories are suggested in this paper such as information quality, system quality, service quality, interface quality and emotional quality. The survey for empirical study was executed with hotel employees and total 149 questionnaires were used for this study. We used AHP for statistical analysis, As the results, the most important factor is emotional quality factor and the next is interface quality factor.

• Journal of Internet Computing and Services
• /
• v.10 no.2
• /
• pp.65-73
• /
• 2009

IEEE802.11 Wireless LAN(WLAN) is being widely used in public space such as airport, and increases the networking boundary in campus and enterprise, and it has lastly attracted considerable attention for mesh network and converged network with other 3G mobile communication networks. In WLAN, load balancing among Access Points(AP) is an important issue for efficient resource management or supporting the Quality of Service(QoS) of traffic, but most researches focused on the AP selection in network entry or roaming of Stations(STA). In this paper, we propose an AP-Initiated Flow Redirection(FR) for AP load balancing by monitoring AP's availability in the true sense. When the AP's resource becomes almost saturated, that is used more than a specific threshold, the AP queries the roaming possible neighbor APs about their availability and calculates the distribution of traffic load with statistical methods such as entropy or chi-square. Finally, the AP decides flows and new APs for redirection and performs it. Our simulation results show that our FR mechanism increases the performance in the various views.

• The Journal of the Korea Contents Association
• /
• v.14 no.11
• /
• pp.16-27
• /
• 2014

In this paper, we propose an efficient grid based routing scheme using the location information in order to reduce the routing cost in mobile ad-hoc networks. In our proposed scheme, all nodes can be a candidate to forward messages to the specified destination node and reduce the management cost of head nodes because they do not exist. The intermediate nodes determine the next hop relaying messages on the basis of location relations between a node and a grid zone. The proposed scheme explores the routing path considering the direction of a node using the coordinate of a grid zone and neighbor node information. It also maintains the routing path considering connectivities among the nodes. In order to show the superiority of the proposed routing scheme, we compare it with the existing grid based routing scheme in terms of the overhead of message, the success rate of transmission.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.9
• /
• pp.1999-2007
• /
• 2010

Proxy Mobile IPv6(PMIPv6) is a network-based mobility management protocol and it does not require mobile node's involving in mobility management. In PMIPv6, the Mobile Access Gateway (MAG) incurs a high signaling cost to update the location of a mobile node to the remote Local Mobility Anchor (LMA) if it moves frequently. It may cause excessive signaling traffic and increase a high traffic load on LMA. Therefore, we propose a new mobility management scheme in proxy mobile IPv6 networks with dynamic paging support. To minimize signaling overhead, in our proposal, the size of the paging area is determined dynamically according the changes of mobility and traffic patterns of the mobile node. An analytic model is applied to determine the optimal size of the paging area. The cost analysis using fluid flow model presented in this paper shows that our proposal can achieve performance superior that of PMIPv6 scheme.

• Journal of Advanced Navigation Technology
• /
• v.13 no.4
• /
• pp.551-558
• /
• 2009

Most of clustering schemes focusing on the energy efficiency have only a cluster head in each cluster, thus the energy consumption of cluster head in a cluster can rapidly increase. To reduce the energy consumption, recently, the dual-layered clustering which is separated a cluster ranges into two parts, i.e., data aggregation layer and data transmission layer, based on a sensor equipped with geographical positioning system (GPS), was proposed. However, the logical regions existing within the dual-layered clustering range can not distinguish efficiently. This scheme leads to many messages collision and transmission delay among member nodes. In this paper, to solve these problems, we propose a separated dual-layered routing scheme using the position information and the cluster radius. Proposed scheme clearly distinguish the dual-layered clustering range and gets the balanced number of member nodes in each cluster. Therefore, the proposed routing scheme could prolong the overall network life time about 10% compared to the previous two layered clustering scheme and LEACH.

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

• Journal of Korea Multimedia Society
• /
• v.6 no.6
• /
• pp.1034-1045
• /
• 2003

In this paper, we study a multicast transport technique for multimedia services of mobile hosts in wireless network environments. To reduce packet loss during hand-off, we propose a Pre-join scheme in overlapped area and a Buffering scheme in crossover routers. To support seamless service in real time multimedia application, these scheme use an optimal path routing which was provided in remote subscription scheme and a prediction scheme of host movements which was considered overlapped area. To evaluate the peformance of our scheme, we compare Bi-direction tunneling of mobile If, Remote subscription, and MoM by using NS-2. As a result, our scheme shows better performance in network overhead, packet loss and bandwidth's use than other schemes.

• Journal of the Korea Society for Simulation
• /
• v.17 no.1
• /
• pp.17-22
• /
• 2008

Double-binary turbo code has been adopted as an error control code of various future communication systems including wireless metropolitan area networks(WMAN) due to its powerful error correction capability. One of the components affecting the performance of turbo code is internal interleaver. In 802.16 d/e system, an almost regular permutation(ARP) interleaver has been included as a part of specification, however it seems that the interleaver is not optimized in terms of decoding performance. In this paper, we propose three optimization methods for the interleaver based on spatial distance, spread and minimum distance between original and interleaved sequence. We find optimized interleaving parameters for each optimization method and evaluate the performances of the proposed methods by computer simulation under additive white Gaussian noise(AWGN) channel. Optimized parameters can provide up to 1.0 dB power gain over the conventional method and furthermore the obtainable gain does not require any additional hardware complexity.