• Title/Summary/Keyword: Virtual Nodes

Search Result 222, Processing Time 0.022 seconds

Development of Easy-to-use VI Programming Library (사용자 편의성을 고려한 VIA 라이브러리 개발에 관한 연구)

  • 이상기;이윤영;서대화
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.27 no.4C
    • /
    • pp.326-332
    • /
    • 2002
  • To transfer the large size of data more quickly among cluster nodes, the lightweight messaging scheme has been developed. VIA(Virtual Interface Architecture) allows that user can directly communicate with network devices without any interference of kernel and has become a communication protocol for clusters. But one must spend a lot of time to be skillful with it because of difficulties of programming. Therefore, we propose an easier library called EVIL(Easy-to-use Virtual Interface Library) that developers can easily deal with. We evaluated the performance of EVIL, Native VIA, TCP/IP respectively.

Overlay Multicast considering Fast Path Recovery (빠른 경로 복구를 고려한 오버레이 멀티캐스트)

  • Gu, Myeong-Mo;Kim, Bong-Gi
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.17 no.3
    • /
    • pp.332-337
    • /
    • 2016
  • The rapid reconstruction of a transfer path is caused by frequent secession of nodes in many applications using overlay multicast. For this, however, many studies have been proposed, but a study of fast path recovery is required. This paper proposes a new method for fast path recovery to improve the path reconstruction time and for stable path maintain caused by the sudden secession of the parent node on overlay multicast. The proposed method uses the virtual transfer path and the candidate parent node for the fast path recovery. All nodes exchange periodically the RTT (Round Trip Time) information between the other nodes of similar position itself and neighboring node. All nodes have a candidate parent node list, and each node stores the exchanged RTT information on the list. Each node constructs the virtual transfer path to reduce the recovery time after deciding a candidate parent node that is one of them by the RTT order. In this way, when the parent node is seceded, all nodes can recover the transfer path quickly using the virtual transfer path. The simulation result showed that the recovery time of the proposed method is an average 30% faster than the known method.

Cluster Based Multi-tier MAC Protocol for Dense Wireless Sensor Network (밀집된 무선센서네트워크를 위한 클러스터 기반의 멀티티어 MAC 프로토콜)

  • Hwan, Moon-Ji;Mu, Chang-Tae
    • Journal of the Korea Society of Computer and Information
    • /
    • v.16 no.2
    • /
    • pp.101-111
    • /
    • 2011
  • A new MAC protocol, MT-MAC(Multi-Tier Medium Access Control) by name, is proposed for dense sensor networks. Depending on the density of nodes in a virtual cluster, the cluster header performs the splitting to several tiers in nodes of virtual cluster. MT-MAC split the tiers to use modfied-SYNC message after receiving the beacon message from the cluster header. Because only the sensor nodes in the same tier communicate each other, less power is consumed and longer network life time is guaranteed. By a simulation method with NS-2, we evaluated our protocol. In dense nodes environments, MT-MAC protocol shows better results than S-MAC in terms of packet delivery rates throughput and energy consumption.

The typd of service and virtual destination node based multicast routing algorithm in ATM network (ATM 통신망에서의 서비스 유형과 경로 충첩 효과를 반영한 멀티캐스트 라우팅 알고리즘)

  • 양선희
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.21 no.11
    • /
    • pp.2886-2896
    • /
    • 1996
  • The Type of Service based multicast routing algorithm is necessary to support efficiently herogeneous applications in ATM network. In this paper I propose the Constrained Multicast Tree with Virtual Destination(DMTVD) heuristic algorithm as least cost multicast routing algorithm. The service is categorized into two types, as delay sensitive and non in CMTVD algorithm. For the delay sensitive service type, the cost optimized route is the Minimum Cost Stenier Tree connecting all the destination node group, virtual destination node group and source node with least costs, subject to the delay along the path being less than the maximum allowable end to end delay. The other side for the non-delay sensitive service, the cost optimized route is the MCST connecting all the multicast groups with least costs, subject to the traffic load is balanced in the network. The CMTVD algorithm is based on the Constrained Multicasting Tree algorithm but regards the nodes branching multiple destination nodes as virtural destination node. The experimental results show that the total route costs is enhanced 10%-15% than the CTM algorithm.

  • PDF

A Geographic Distributed Hash Table for Virtual Geographic Routing in MANET (MANET에서 가상 위치 기반 라우팅을 위한 지역 분산 해쉬 테이블 적용 방법)

  • Ko, Seok-Kap;Kim, Young-Han
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.45 no.12
    • /
    • pp.58-65
    • /
    • 2008
  • This paper presents a new geographic distributed hash table (GDHT) for MANETs or Mesh networks, where virtual geographic protocol is used. In previous wort GDHT is applied to a network scenario based on two dimensional Cartesian coordinate system. Further, logical data space is supposed to be uniformly distributed. However, mobile node distribution in a network using virtual geographic routing is not matched to data distribution in GDHT. Therefore, if we apply previous GDHT to a virtual geographic routing network, lots of DHT data are probably located at boundary nodes of the network or specific nodes, resulting in long average-delay to discover resource (or service). Additionally, in BVR(Beacon Vector Routing) or LCR(Logical Coordinate Routing), because there is correlation between coordinate elements, we cannot use normal hash function. For this reason, we propose to use "geographic hash function" for GDHT that matches data distribution to node distribution and considers correlation between coordinate elements. We also show that the proposed scheme improves resource discovery efficiently.

Security Improvement of Authentication Method Using Transfer Agent in USN

  • Cho, Do-Eun
    • International Journal of Contents
    • /
    • v.7 no.4
    • /
    • pp.35-43
    • /
    • 2011
  • USN is a technology to detect human external environment. It is an important factor in buildinga ubiquitous computing environment. In this thesis, an authentication method was proposed to allow the sensor nodes, which have weak computing operation capability, to safely communicate with each other in USN and guarantee the anonymity of users for their privacy. In the proposed authentication method that takes into account the characteristics of sensor network, sensor nodes based on a symmetric key algorithm do not transfer keys directly, instead, they mix the random numbers received from AS to generate keys necessary for communications, having a master key and a pseudo-random number generator.In addition, in this thesis, TA was adopted to minimize the leakage of users' information, and a scheme through which virtual IDs received from AS are delivered to sensor nodes was applied to improve anonymity.

P2P Networking based on CAN for Effective Multimedia Contents Sharing (효율적인 멀티미디어 콘텐츠 공유를 위한 CAN 기반 P2P 네트워킹)

  • 박찬모;김종원
    • Proceedings of the IEEK Conference
    • /
    • 2003.11a
    • /
    • pp.259-262
    • /
    • 2003
  • A efficient P2P (peer to peer) networking for sharing multimedia contents is proposed to overcome the limitations of unstructured approaches. The proposed approach is attempting to organize the participating P2P nodes by modifying a n-dimensional cartesian-coordinate space DHT (distributed hash table), CAN (content addressable network). The network identifiers (e.g., network prefix of IP address) of participating nodes are mapped into the CAN virtual coordinate space (in 2-d) and nodes with similar identifiers are grouped into the same zone. The proposed scheme is expected to show some level of concentration reflecting the network identifiers. Network simulator-based evaluation is performed to verify the effectiveness of the proposed scheme.

  • PDF

A Game Theoretic Study of Energy Efficient Cooperative Wireless Networks

  • Brown, Donald Richard III;Fazel, Fatemeh
    • Journal of Communications and Networks
    • /
    • v.13 no.3
    • /
    • pp.266-276
    • /
    • 2011
  • In wireless networks, it is well-known that intermediate nodes can be used as cooperative relays to reduce the transmission energy required to reliably deliver a message to an intended destination. When the network is under a central authority, energy allocations and cooperative pairings can be assigned to optimize the overall energy efficiency of the network. In networks with autonomous selfish nodes, however, nodes may not be willing to expend energy to relay messages for others. This problem has been previously addressed through the development of extrinsic incentive mechanisms, e.g., virtual currency, or the insertion of altruistic nodes in the network to enforce cooperative behavior. This paper considers the problem of how selfish nodes can decide on an efficient energy allocation and endogenously form cooperative partnerships in wireless networks without extrinsic incentive mechanisms or altruistic nodes. Using tools from both cooperative and non-cooperative game theory, the three main contributions of this paper are (i) the development of Pareto-efficient cooperative energy allocations that can be agreed upon by selfish nodes, based on axiomatic bargaining techniques, (ii) the development of necessary and sufficient conditions under which "natural" cooperation is possible in systems with fading and non-fading channels without extrinsic incentive mechanisms or altruistic nodes, and (iii) the development of techniques to endogenously form cooperative partnerships without central control. Numerical results with orthogonal amplify-and-forward cooperation are also provided to quantify the energy efficiency of a wireless network with sources selfishly allocating transmission/relaying energy and endogenously forming cooperative partnerships with respect to a network with centrally optimized energy allocations and pairing assignments.

3D Navigation Real Time RSSI-based Indoor Tracking Application

  • Lee, Boon-Giin;Lee, Young-Sook;Chung, Wan-Young
    • Journal of Ubiquitous Convergence Technology
    • /
    • v.2 no.2
    • /
    • pp.67-77
    • /
    • 2008
  • Representation of various types of information in an interactive virtual reality environment on mobile devices had been an attractive and valuable research in this new era. Our main focus is presenting spatial indoor location sensing information in 3D perception in mind to replace the traditional 2D floor map using handheld PDA. Designation of 3D virtual reality by Virtual Reality Modeling Language (VRML) demonstrates its powerful ability in providing lots of useful positioning information for PDA user in real-time situation. Furthermore, by interpolating portal culling algorithm would reduce the 3D graphics rendering time on low power processing PDA significantly. By fully utilizing the CC2420 chipbased sensor nodes, wireless sensor network was established to locate user position based on Received Signal Strength Indication (RSSI) signals. Implementation of RSSI-based indoor tracking method is low-cost solution. However, due to signal diffraction, shadowing and multipath fading, high accuracy of sensing information is unable to obtain even though with sophisticated indoor estimation methods. Therefore, low complexity and flexible accuracy refinement algorithm was proposed to obtain high precision indoor sensing information. User indoor position is updated synchronously in virtual reality to real physical world. Moreover, assignment of magnetic compass could provide dynamic orientation information of user current viewpoint in real-time.

  • PDF

Efficient Processing of Huge Airborne Laser Scanned Data Utilizing Parallel Computing and Virtual Grid (병렬처리와 가상격자를 이용한 대용량 항공 레이저 스캔 자료의 효율적인 처리)

  • Han, Soo-Hee;Heo, Joon;Lkhagva, Enkhbaatar
    • Journal of Korea Spatial Information System Society
    • /
    • v.10 no.4
    • /
    • pp.21-26
    • /
    • 2008
  • A method for processing huge airborne laser scanned data using parallel computing and virtual grid is proposed and the method is tested by generating raster DSM(Digital Surface Model) with IDW(Inverse Distance Weighting). Parallelism is involved for fast interpolation of huge point data and virtual grid is adopted for enhancing searching efficiency of irregularly distributed point data. Processing time was checked for the method using cluster constituted of one master node and six slave nodes, resulting in efficiency near to 1 and load scalability property. Also large data which cannot be processed with a sole system was processed with cluster system.

  • PDF