• ETRI Journal
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• v.35 no.2
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• pp.234-244
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• 2013

Internet protocol television (IPTV) service depends on the network quality of service (QoS) and bandwidth of the broadband service provider. IEEE 802.16j mobile multihop relay Worldwide Interoperability for Microwave Access networks have the opportunity to offer high bandwidth capacity by introducing relay stations. However, to actually satisfy QoS requirements for offering IPTV services (HDTV, SDTV, Web TV, and mobile TV) for heterogeneous users' requests, providers must use a video server for each IPTV service type, which increases the network load, especially bandwidth consumption and forwarding time. In this paper, we present a solution for forwarding IPTV video streaming to diverse subscribers via an 802.16j broadband wireless access network. In particular, we propose a new multicast tree construction and aggregation mechanism based on the unique property of prime numbers. Performance evaluation results show that the proposed scheme reduces both bandwidth consumption and forwarding time.

• IE interfaces
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• v.20 no.1
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• pp.41-48
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• 2007

The main purpose of this paper is cost reduction in absurd pilot positive expense and human accident prevention which is caused by in the pilot selection process. We use classification models such as logistic regression, decision tree, and neural network based on aptitude test results of 505 ROK Air Force applicants in 2001~2004. First, we determine the reliability and propriety against the aptitude test system which has been improved. Based on this conference flight simulator test item was compared to the new aptitude test item in order to make additional yes or no decision from different models in terms of classification accuracy, ROC and Response Threshold side. Decision tree was selected as the most efficient for each sequential flight training result and the last flight training results predict excellent. Therefore, we propose that the standard of pilot selection be adopted by the decision tree and it presents in the aptitude test item which is new a conference flight simulator test.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.499-510
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• 2007

Shortest path tree(SPT) construction is essential in high performance routing in an interior network using link state protocols. When some links have new state values, SPTs may be rebuilt, but the total rebuilding of the SPT in a static way for a large computer network is not only computationally expensive, unnecessary modifications can cause routing table instability. This paper presents a new update algorithm, dynamic shortest path tree(DSPT) that is computationally economical and that maintains the unmodified nodes mostly from an old SPT to a new SPT. The proposed algorithm reduces redundancy using a dynamic update approach where an edge becomes the significant edge when it is extracted from a built edge list Q. The average number of significant edges are identified through probability analysis based on an arbitrary tree structure. An update derived from significant edges is more efficient because the DSPT algorithm neglect most other redundant edges that do not participate in the construction of a new SPT. Our complexity analysis and experimental results show that DSPT is faster than other known methods. It can also be extended to solve the SPT updating problem in a graph with negative weight edges.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.261-270
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• 2009

We propose a tree-based integration of infrastructure networks and MANETs (TUM) to efficiently extend the scope of mobile Internet protocol to mobile ad hoc networks and devise a tree-based routing protocol (TBRP) that is suitable for the TUM architecture. Infrastructure networks have a number of fixed Internet Gateways that connect two heterogeneous networks. Mobile nodes form a number of small trees named pMANETs, each of them growing from anchor node which can communicate directly with an Internet Gateway. A new node registers with foreign agent and home agent along the tree path without resorting to an inefficient flooding. Furthermore, the TBRP sets up a routing path efficiently by exploiting the tree information without relying on flooding. We show by resorting to simulation that our approach is competitive against the conventional AODV based approach.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.5
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• pp.191-198
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• 2013

It is required to transmit data through shorter path between sensor and base node for real time intrusion detection in wireless sensor networks (WSN) with a mobile base node. Because minimum Wiener index spanning tree (MWST) based routing approach guarantees lower average hop count than that of minimum spanning tree (MST) based routing method in WSN, it is known that MWST based routing is appropriate for real time intrusion detection. However, the minimum Wiener index spanning tree problem which aims to find a spanning tree which has the minimum Wiener index from a given weighted graph was proved to be a NP-hard. And owing to its high dependency on certain nodes, minimum Wiener index tree based routing method has a shorter network lifetime than that of minimum spanning tree based routing method. In this paper, we propose a multi-objective ant colony optimization algorithm to tackle these problems, so that it can be used to detect intrusion in real time in wireless sensor networks with a mobile base node. And we compare the results of our proposed method with MST based routing and MWST based routing in respect to average hop count, network energy consumption and network lifetime by simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.5
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• pp.1303-1315
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• 2012

In the draft of the IEEE 802.11s standard, a tree topology is established by the proactive tree-building mode of the Hybrid Wireless Mesh Protocol (HWMP). It is used for cases in which the root station (e.g., gateway) is an end point of the majority of the data connections. In the tree topology, the root or central stations (e.g., parent stations) are connected to the other stations (e.g., leaves) that are one level lower than the central station. Such mesh stations are likely to suffer heavily from contention in bottleneck links when the network has a high traffic load. Moreover, the dependence of the network on such stations is a point of vulnerability. A failure of the central station (e.g., a crash or simply going into sleep mode to save energy) can cripple the whole network in the tree topology. This causes performance degradation for end-to-end transmissions. In a connected mesh topology where the stations having two or more radio links between them are connected in such a way that if a failure subsists in any of the links, the other link could provide the redundancy to the network. We propose a scheme to utilize this characteristic by organizing the network into concentric tiers around the root mesh station. The tier structure facilitates path recovery and congestion control. The resulting mode is referred to as Tier-based Proactive Path Selection Mode (TPPSM). The performance of TPPSM is compared with the proactive tree mode of HWMP. Simulation results show that TPPSM has better performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4531-4535
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• 2011

In this paper, USN(Ubiquitous Sensor Network) is used in the structure of the tree routing was implemented in embedded systems. Tree Routing in the USN to the sink node to transmit sensor data is one of the techniques. When routing, sensor data is transmitted based on pre-defined ID according hop number. In order to have optimal routing path, the current state of the wireless sector and the sensor node informations were used. Also, received sensor data and the results of the tree routing by implementing an embedded system. This embedded system can be applied to a portable sensor information collecting system.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.572-575
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• 2011

It is well known that spanning tree protocol (STP) is the most commonly used protocol in switching networks for smart grid. STP selectively blocks redundancy links of the network to prevent layer 2 loops in network, and it also has a functionality of backing up links. As with the other protocols, STP has been updated with the continuing development of the network. STP is a broad concept and it does not just refer in particular to defined STP protocol in IEEE 802.1D standards, it refers to updated spanning tree protocol based on STP. Because of uneven distribution of communication traffic in root bridge, STP cannot satisfy fast converge nce while the failure occurs near the root bridge or on the root bridge in tree topologies of STP. In this paper, we propose a novel method --- Hyper Cube Spanning Tree Protocol (HCSTP) to solve uneven distribution of communication traffic. Theoretically, hyper cube in our protocol increases throughput and improves the utilization of communication. The simulation results show that HCSTP can achieve comparative and considerably higher performance than other STP protocols in terms of reconnection.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.1
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• pp.61-71
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• 2007

The main purpose of this study was to develop Automatic Measurement System for monitoring tree's vigor using Ubiquitous Sensor Network This study also focused on presenting an alternative for monitoring automatically tree's vigor due to Shigometer's limits. Application test of the system in comparison with Shigometer showed that the measurement values were not different to choose between the two, and battery lasted about 1,844 days in this system. To test the sensor network the possible transmission distance using the sensor network in maximum was 130m. Investigation and management expenses can be reduced and labor productivity will also be improved in the forest and street trees.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.187-189
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• 2000

Nowadays, efforts are in progress for the standardization of CORBAbased telecommunication network management framework. To implement a network management system based on the framework completely, CORBA ORB and some of CORBA service should be installed in the element. And then, there must be the naming tree, which correspond to the containment relationships between components in the network element. If we use conventional OMG naming service to form the naming tree, all MOs, a software fragmenthat corresponds to each component in a system, should be instantiated. However, the network element is usually a kind of limited resource system, which cannot provide sufficient resources for applications run on it. Hence, instantiatingall MOs can cause problems for that kind of system, This paper presents Smart Naming Service architecture as a solution to the problem.