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An Energy-Aware Multi-tree Video Multicast Scheme in Wireless Ad Hoc Networks (무선 애드 혹 네트워크에서 잔여 에너지를 고려한 다중 트리 비디오 멀티캐스트 기법)

  • Park, Jae-Young;Kang, Kyung-Ran;Cho, Young-Jong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.12B
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    • pp.1336-1348
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    • 2009
  • In this paper, we propose an energy-aware multi-tree video multicast scheme for wireless ad hoc networks. Some network nodes may have energy enough to receive and forward the whole video content whereas some may not. Even though the video quality may vary depending on the remaining energy, our scheme enables the low-energy nodes to join the video multicast session. The video stream is split into a set of multiple and independent descriptions by MDC (Multiple description coding) scheme. Each description corresponds to a substream and number of substreams determine the video quality. The member nodes determine how many substreams it would receive depending on the remaining energy and expected amount of packets per substream. So does the intermediate tree nodes. That builds a tree per substream and multiple trees per session. The data source disseminates each substream through corresponding tree. The video quality of the member nodes varies according to number of participating trees. We evaluate the performance of our scheme by simulation. Our scheme showed better peak signal to noise ratio and extended the lifetime of the network nodes compared with MAODV, which builds a single tree, and MT-MAODV, which builds multiple trees but does not consider the available energy.

Multicast Support in DiffServ Using Mobile Agents

  • El Hachimi, Mohamed;Abouaissa, Abdelhafid;Lorenz, Pascal
    • ETRI Journal
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    • v.27 no.1
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    • pp.13-21
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    • 2005
  • Many multicast applications, such as video-on-demand and video conferencing, desire quality of service (QoS) support from an underlying network. The differentiated services (DiffServ) approach will bring benefits for theses applications. However, difficulties arise while integrating native IP multicasting with DiffServ, such as multicast group states in the core routers and a heterogeneous QoS requirement within the same multicast group. In addition, a missing per-flow reservation in DiffServ and a dynamic join/leave in the group introduce heavier and uncontrollable traffic in a network. In this paper, we propose a distributed and stateless admission control in the edge routers. We also use a mobile agents-based approach for dynamic resource availability checking. In this approach, mobile agents act in a parallel and distributed fashion and cooperate with each other in order to construct the multicast tree satisfying the QoS requirements.

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Modeling and Implementation for Generic Spatio-Temporal Incorporated Information (시간 공간 통합 본원적 데이터 모델링 및 그 구현에 관한 연구)

  • Lee Wookey
    • Journal of Information Technology Applications and Management
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    • v.12 no.1
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    • pp.35-48
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    • 2005
  • An architectural framework is developed for integrating geospatial and temporal data with relational information from which a spatio-temporal data warehouse (STDW) system is built. In order to implement the STDW, a generic conceptual model was designed that accommodated six dimensions: spatial (map object), temporal (time), agent (contractor), management (e.g. planting) and tree species (specific species) that addressed the 'where', 'when', 'who', 'what', 'why' and 'how' (5W1H) of the STDW information, respectively. A formal algebraic notation was developed based on a triplet schema that corresponded with spatial, temporal, and relational data type objects. Spatial object structures and spatial operators (spatial selection, spatial projection, and spatial join) were defined and incorporated along with other database operators having interfaces via the generic model.

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Implementation and Performance Evaluation of Parallel Multi-way Spatial Join (병렬 다중 공간 조인 알고리즘의 구현 및 성능평가)

  • 류우석;김진덕;홍봉희
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10b
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    • pp.123-125
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    • 1998
  • 지리 정보 시스템이서 다중 공간 조인과 같은 많은 기하 계산을 필요로 하는 질의를 처리하기 위해서는 질의에 대한 병렬화 작업을 통해 실행 시간을 최소화 하는 것이 필수적이다. 다중 공간 조인은 정제에서 많은 시간을 소비하므로 여과와 정제를 분리하여 각각을 수행하는 것이 정제 시간을 단축하게 되고 따라서 좋은 성능을 나타낼 수 있다. 그러므로 다중 공간 조인을 병렬화 하기 위해서는 다중 공간 여과와 정제 각각에 대해 병렬 실행 계획을 세우는 것이 중요하다. 이 논문에서는 우선적으로 병렬 공간 여과를 수행하기 위한 두가지 알고리즘, 즉 blush tree을 사용한 다중 공간 여과와 pipelining을 사용한 다중 공간 여과의 병렬화를 비교한다. 그리고, 다중 공간 여과의 결과로서 생성되는 중간 결과 테이블에서 데이터의 중복에 따라 정제 성능의 저하가 발생되는데, 이를 효율적으로 제거하기 위한 두가지 그래프 생성 알고리즘을 제안하고 이를 비교한다. 그리고, 생성된 그래프에서 병렬 정제를 수행하기 위한 여러 가지 분할 알고리즘을 제안하고 이를 비교 평가한다. 이런 일련의 작업을 통해 우수한 성능의 병렬 다중 공간 조인 방법을 제안하고 성능 평가를 통해 최적의 병렬 수행 방법을 도출한다.

An efficient dynamic routing scheme for delay-bounded multicasting

  • Kang, Moon-Sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.12
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    • pp.2626-2634
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    • 1997
  • The purpose of multicasting is to reduce the network costs for transmitting the same traffic to multiple destinations. In this paper, an efficient delay-bounded multicasting routing algorithm is proposed, which satistifies the network conditions of cost minimization and can adjust the dynamic events, such as 'leave and/or join ones' from the multicast group. Also, our algorithm is designed for various network requirements such as the efficiet dynamic group support, high-quality data distribution, and adaptability to variable situation. After the delay tolerance and the maximum group size are determined according to network state and requirements for delay and cost, the dynamic delay-bounded multicast tree is constructed using partial multicast routing. We evaluate the performance of the proposed algorithm by running simulations on randomly generated test networks using a Sun Sparc 20 workstation. We were able to obtain good simulation resutls, which means solutions that lies between the minimum cost solution and the minimum delay one.

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Materialized View Selection Scheme for enhancing RDF Query Performance (RDF 질의 처리 성능 향상을 위한 실체 뷰 선택 기법)

  • Park, Jaeyeol;Yoon, Sangwon;Choi, Kitae;Lim, Jongtae;Lee, Byoungyup;Shin, Jaeryong;Bok, Kyoungsoo;Yoo, Jaesoo
    • The Journal of the Korea Contents Association
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    • v.15 no.12
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    • pp.24-34
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    • 2015
  • With the development of the semantic web, a large amount of data being produced nowadays is in RDF format. RDF is represented by a triple. An RDF database consisting of triples requires the high cost of join query processing. Materialized view is known as a scheme to reduce the query processing cost by accessing materialized views without accessing the database. It is physically stored the results or the intermediate results of the query processing in a storage area. In this paper, we propose a materialized view selection scheme by using decision tree to solve such a problem. The decision tree considers the size and maintenance costs of the materialized view as well as the profit of query response times. It is shown through performance evaluation that the proposed scheme increases the number of materialized views in the limited storage space and decreases the update rates of the materialized views.

Privilege Management Technique for Unreliable Network Environments based on Tree Structure (신뢰도가 낮은 네트워크 환경을 위한 트리 구조 기반의 권한 관리 기법)

  • Yang, Soo-Mi
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.18 no.5
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    • pp.83-91
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    • 2008
  • IISO/IEC 9594-8 defines the public key framework and attribute certificate framework. Attribute certificate framework deals with privilege management infrastructure(PMI). In PMI, for privilege management using attribute certificates, role assignment certificates and role specification certificates are used to assign and specify privileges independently. Role specification certificates includes privilege specifications and the details far privilege management of network environments. Privilege management of unreliable network environment tries to enhance the reliability and efficiency of privilege information transmission forwarding over unreliable routes in the presence of potentially faulty nodes and edges. Each node forms a role specification tree based on role specification relationship data collected from the network. In this paper privilege management cost with the role specification certificates tree structure is evaluated trying to reduce the overhead incurred by role creation and modification of privileges. The multicasting of packets are used for scalability. We establish management cost model taking into account the packet loss and node reliability which continuously join and leave for network. We present quantitative results which demonstrate the effectiveness of the proposed privilege management scheme.

Building Low Delay Application Layer Multicasting Trees for Streaming Services (스트리밍 서비스를 위한 적은 지연의 응용계층 멀티캐스트 트리 구축)

  • Kim, Jong-Gyung
    • The Journal of the Korea Contents Association
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    • v.8 no.10
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    • pp.20-26
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    • 2008
  • The quality of stream remaking is decided the load of a server and Jitter through the traffic of the transmission path between end to end. In order to improve these problems in this paper, I propose tree construction method of low-delay-level-multicast. In this case which the network congestion will be occurred by streaming quality, I also propose the technique which dynamically changes the transmission path. This technique first constructs the overlay structure for relaxing the overload of server. Secondly, in order to decrease Jitter of client, it makes upload bandwidth and low latency balanced. In the evaluation of the performance, this paper showed better enhancement of about 15 than P2CAST[4] in the simulation about node average join count, average bandwidth, service request refusal ratio, RTT measurement of nodes, and node average join count by defect ratio.

An Efficient Routing Scheme based on Link Quality and Load Balancing for Wireless Sensor Networks (무선 센서 네트워크에서 링크 상태 및 트래픽 분산 정보를 이용한 효과적인 라우팅 방법)

  • Kim, Sun-Myeng;Yang, Yeon-Mo
    • Journal of the Korea Society for Simulation
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    • v.19 no.4
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    • pp.11-19
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    • 2010
  • ZigBee is a standard for wireless personal area networks(WPANs) based on the IEEE 802.15.4 standard. It has been developed for low cost and low power consumption. There are two alternative routing schemes that have been proposed for the ZigBee standard: Ad-hoc On-Demand Distance Vector(AODV) and tree routing. The tree routing forwards packets from sensors to a sink node based on the parent-child relationships established by the IEEE 802.15.4 MAC topology formation procedure. In order to join the network, a sensor node chooses an existing node with the strongest RSSI(Received signal strength indicator) signal as a parent node. Therefore, some nodes carry a large amount of traffic load and exhaust their energy rapidly. To overcome this problem, we introduce a new metric based on link quality and traffic load for load balancing. Instead of the strength of RSSI, the proposed scheme uses the new metric to choose a parent node during the topology formation procedure. Extensive simulation results using TOSSIM(TinyOS mote SIMulator) show that the CFR scheme outperforms well in comparison to the conventional tree routing scheme.

A Mobile Multicasting Mechanism Based on Mobility Information of Mobile Hosts (호스트의 이동 정보에 근거한 모바일 멀티캐스팅 기법)

  • Baek DeukHwa;Kim Jaesoo
    • Journal of Korea Multimedia Society
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    • v.8 no.2
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    • pp.258-268
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    • 2005
  • The efficient provision of multicast service to moving hosts in mobile computing environments is not so easy task. Bi-directional tunneling scheme causes overhead about encapsulation and triangular routing. On the other hand, remote subscription scheme need freDuent tree reconstruction, which is inefficient for rapid moving hosts. In this paper we propose Mobility Based Mobile Multicast(MBMOM) scheme which is based on host's mobility information. Ultimately MBMOM try to find the strong points of remote subscription scheme and hi-directional tunneling scheme. If host's mobility speed is considered to be high, multicast packets are forwarded using hi-directional tunneling scheme from home agent continuously. If host's mobility speed is considered to be slow, remote subscription scheme is applied for foreign agent and it try to join multicast tree. We developed analytical models to analyze the performance of proposed scheme and simulated our scheme compared with MOM(Mobile Multicast), RBMOM(Range Based MOM), and TBMOM(Timer Based MOM) schemes. Simulation results show that our scheme has shorter transmission delay than above 3 schemes in the aspect of host's mobility speed and multicast group size.

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