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Sample records for ad-hoc routing protocol

  1. Receiver-Based Ad Hoc On Demand Multipath Routing Protocol for Mobile Ad Hoc Networks

    PubMed Central

    Al-Nahari, Abdulaziz; Mohamad, Mohd Murtadha

    2016-01-01

    Decreasing the route rediscovery time process in reactive routing protocols is challenging in mobile ad hoc networks. Links between nodes are continuously established and broken because of the characteristics of the network. Finding multiple routes to increase the reliability is also important but requires a fast update, especially in high traffic load and high mobility where paths can be broken as well. The sender node keeps re-establishing path discovery to find new paths, which makes for long time delay. In this paper we propose an improved multipath routing protocol, called Receiver-based ad hoc on demand multipath routing protocol (RB-AOMDV), which takes advantage of the reliability of the state of the art ad hoc on demand multipath distance vector (AOMDV) protocol with less re-established discovery time. The receiver node assumes the role of discovering paths when finding data packets that have not been received after a period of time. Simulation results show the delay and delivery ratio performances are improved compared with AOMDV. PMID:27258013

  2. Routing Protocol of Sparse Urban Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Li, Huxiong

    Vehicular ad hoc network (VANET) is an application of mobile ad hoc technology in transportation systems, it has become an important part of ITS. Since multi-hop link is hard to set up in sparse VANET, a traffic-aware routing (TAR) protocol is proposed which estimates vehicle average neighbors (VAN) of roads by exchanging beacon messages between encounter vehicles. Road with high VAN is preferred to be selected as part of forwarding path at intersection. Packets are forwarded to the next intersection in road in a greedy manner. Simulations show that TAR outperforms the compared protocols in terms of both packet delivery ratio and average end-to-end delay.

  3. Intelligent routing protocol for ad hoc wireless network

    NASA Astrophysics Data System (ADS)

    Peng, Chaorong; Chen, Chang Wen

    2006-05-01

    A novel routing scheme for mobile ad hoc networks (MANETs), which combines hybrid and multi-inter-routing path properties with a distributed topology discovery route mechanism using control agents is proposed in this paper. In recent years, a variety of hybrid routing protocols for Mobile Ad hoc wireless networks (MANETs) have been developed. Which is proactively maintains routing information for a local neighborhood, while reactively acquiring routes to destinations beyond the global. The hybrid protocol reduces routing discovery latency and the end-to-end delay by providing high connectivity without requiring much of the scarce network capacity. On the other side the hybrid routing protocols in MANETs likes Zone Routing Protocol still need route "re-discover" time when a route between zones link break. Sine the topology update information needs to be broadcast routing request on local zone. Due to this delay, the routing protocol may not be applicable for real-time data and multimedia communication. We utilize the advantages of a clustering organization and multi-routing path in routing protocol to achieve several goals at the same time. Firstly, IRP efficiently saves network bandwidth and reduces route reconstruction time when a routing path fails. The IRP protocol does not require global periodic routing advertisements, local control agents will automatically monitor and repair broke links. Secondly, it efficiently reduces congestion and traffic "bottlenecks" for ClusterHeads in clustering network. Thirdly, it reduces significant overheads associated with maintaining clusters. Fourthly, it improves clusters stability due to dynamic topology changing frequently. In this paper, we present the Intelligent Routing Protocol. First, we discuss the problem of routing in ad hoc networks and the motivation of IRP. We describe the hierarchical architecture of IRP. We describe the routing process and illustrate it with an example. Further, we describe the control manage

  4. Routing Protocols to Minimize the Number of Route Disconnections for Communication in Mobile Ad Hoc Networks

    DTIC Science & Technology

    2009-09-01

    Broch , "DSR: The Dynamic Source Routing Protocol for Multi-hop Wireless Ad hoc Networks," in Ad hoc Networking, Chapter 5, C. E. Perkins, Eds. Addison...Project Report: 09/23/2008 to 09/22/2009 W911NF-08-2-0061 References [I] J. Broch , D. A. Maltz, D. B. Johnson, Y. C. Hu and J. Jetcheva, "A...and Mobile Computing, Vol. 2, pp. 723 - 726, Sept. 2005. [4] D. B. Johnson, D. A. Maltz and J. Broch , "DSR: The Dynamic Source Routing Protocol for

  5. Performance Evaluation of Ad Hoc Routing Protocols in a Swarm of Autonomous Unmanned Aerial Vehicles

    DTIC Science & Technology

    2007-03-01

    research in mobile, ad hoc routing protocols. Broch , et al. performed a simulation comparison of the DSDV, DSR, AODV and Temporally-Ordered...July 6, 2005. [Bel58] R. Bellman, “On a Routing Problem,” in Quarterly of Applied Mathematics, 16(1), pp.87-90, 1958. [BJM04] J. Broch , D. B...vol. AD- A404703, 2002. [BMJ98] J. Broch , D. A. Maltz, D. B. Johnson, Y. Hu and J. Jetcheva, “A performance comparison of multi-hop wireless ad hoc

  6. Performance Analysis of Mobile Ad Hoc Networking Routing Protocols

    DTIC Science & Technology

    2004-12-01

    process of establishing the DAG is similar to the query and reply process as proposed in a light-weight mobile routing (LMR) [ Corson 1995]. Upon link...2004. [RIP RFC] RIP Version 2 RFC Website. http://www.faqs.org/rfcs/rfc2453.html accessed on 1 October 2004. [Royer 1999] Elizabeth M. Royer & C

  7. A Comprehensive Performance Comparison of On-Demand Routing Protocols in Mobile Ad-Hoc Networks

    NASA Astrophysics Data System (ADS)

    Khan, Jahangir; Hayder, Syed Irfan

    Mobile ad hoc network is an autonomous system of mobile nodes connected by wireless links. Each node operates not only as an end system, but also as a router to forward packets. The nodes are free to move about and organize themselves on a fly. In this paper we focus on the performance of the on-demand routing protocols such as DSR and AODV in ad-hoc networks. We have observed the performance change of each protocol through simulation with varying the data in intermediate nodes and to compare data throughput in each mobile modes of each protocol to analyze the packet fraction for application data. The objective of this work is to evaluate two routing protocols such as On-demand behavior, namely, Ad hoc Demand Distance vector (AODV) and Dynamic Source Routing (DSR), for wireless ad hoc networks based on performance of intermediate nodes for the delivery of data form source to destination and vice versa in order to compare the efficiency of throughput in the neighbors nodes. To overcome we have proposed OPNET simulator for performance comparison of hop to hop delivery of data packet in autonomous system.

  8. Intelligent QoS routing algorithm based on improved AODV protocol for Ad Hoc networks

    NASA Astrophysics Data System (ADS)

    Huibin, Liu; Jun, Zhang

    2016-04-01

    Mobile Ad Hoc Networks were playing an increasingly important part in disaster reliefs, military battlefields and scientific explorations. However, networks routing difficulties are more and more outstanding due to inherent structures. This paper proposed an improved cuckoo searching-based Ad hoc On-Demand Distance Vector Routing protocol (CSAODV). It elaborately designs the calculation methods of optimal routing algorithm used by protocol and transmission mechanism of communication-package. In calculation of optimal routing algorithm by CS Algorithm, by increasing QoS constraint, the found optimal routing algorithm can conform to the requirements of specified bandwidth and time delay, and a certain balance can be obtained among computation spending, bandwidth and time delay. Take advantage of NS2 simulation software to take performance test on protocol in three circumstances and validate the feasibility and validity of CSAODV protocol. In results, CSAODV routing protocol is more adapt to the change of network topological structure than AODV protocol, which improves package delivery fraction of protocol effectively, reduce the transmission time delay of network, reduce the extra burden to network brought by controlling information, and improve the routing efficiency of network.

  9. Analysis and Proposal of Position-Based Routing Protocols for Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Okada, Hiraku; Takano, Akira; Mase, Kenichi

    One of the most promising applications of a mobile ad hoc network is a vehicular ad hoc network (VANET). Each vehicle is aware of its position information by GPS or other methods, so position-based routing is a useful approach in VANET. The position-based routing protocol can be classified roughly into a next-hop forwarding method and a directed flooding method. We evaluate performance of both methods by analytic approach and compare them in this paper. From the evaluation results, we conclude that it is effective for the position-based routing to choose either the next-hop forwarding method or the directed flooding method according to the environment. Then we propose the hybrid transmission method which can select one of them according to the environment, and clarify that the proposed method can keep the packet delivery ratio at a high level and reduce the delay time.

  10. A Performance Comparison of On-Demand Multicast Routing Protocols for Ad Hoc Networks

    DTIC Science & Technology

    2004-12-15

    33–44, October 2001. [10] L. Ji and M. S. Corson . A Lightweight Adaptive Multicast Algorithm. In Proceedings of IEEE GLOBECOM ’98, pages 1036–1042...December 1998. [11] L. Ji and M. S. Corson . Differential Destination Multicast (DDM) Specification. Internet- Draft, draft-ietf-manet-ddm-00.txt, July... Elizabeth M. Royer and Charles E. Perkins. Multicast Operation of the Ad-hoc On- Demand Distance Vector Routing Protocol. In Proceedings of the Fifth

  11. A Secure 3-Way Routing Protocols for Intermittently Connected Mobile Ad Hoc Networks

    PubMed Central

    Parasuraman, Ganesh Kumar

    2014-01-01

    The mobile ad hoc network may be partially connected or it may be disconnected in nature and these forms of networks are termed intermittently connected mobile ad hoc network (ICMANET). The routing in such disconnected network is commonly an arduous task. Many routing protocols have been proposed for routing in ICMANET since decades. The routing techniques in existence for ICMANET are, namely, flooding, epidemic, probabilistic, copy case, spray and wait, and so forth. These techniques achieve an effective routing with minimum latency, higher delivery ratio, lesser overhead, and so forth. Though these techniques generate effective results, in this paper, we propose novel routing algorithms grounded on agent and cryptographic techniques, namely, location dissemination service (LoDiS) routing with agent AES, A-LoDiS with agent AES routing, and B-LoDiS with agent AES routing, ensuring optimal results with respect to various network routing parameters. The algorithm along with efficient routing ensures higher degree of security. The security level is cited testing with respect to possibility of malicious nodes into the network. This paper also aids, with the comparative results of proposed algorithms, for secure routing in ICMANET. PMID:25136697

  12. Characterizing the Interaction Between Routing and MAC Protocols in Ad-Hoc Networks

    SciTech Connect

    Barrett, C. L.; Drozda, M.; Marathe, A.; Marathe, M. V.

    2002-01-01

    We empirically study the effect of mobility on the performance of protocols designed for wireless ad-hoc networks. An important objective is to study the interaction of the Routing and MAC layer protocols under different mobility parameters. We use three basic mobility models: grid mobility model, random waypoint model, and exponential correlated random model. The performance of protocols is measured in terms of (i) latency, (ii) throughput, (iii) number of packets received, (iv) long term fairness and (v) number of control packets at the MAC and routing layer level. Three different commonly studied routing protocols are used: AODV, DSR and LAR1. Similarly three well known MAC protocols are used: MACA, 802.1 1 and CSMA. Our main contribution is simulation based experiments coupled with rigorous statistical analysis to characterize the interaction of MAC layer protocols with routing layer protocols in ad-hoc networks. From the results, we can conclude the following: e No single MAC or Routing protocol dominated the other protocols in their class. Probably more interestingly, no MAURouting protocol combination was better than other combinations over all scenarios and response variables. 0 In general, it is not meaningful to speak about a MAC or a routing protocol in isolation. Presence of interaction leads to trade-offs between the amount of control packets generated by each layer. The results raise the possibility of improving the performance of a particular MAC layer protocol by using a cleverly designed routing protocol or vice-versa. Thus in order to improve the performanceof a communication network, it is important to study the entire protocol stack as a single algorithmic construct; optimizing individual layers in the seven layer OS1 stack will not yield performance improvements beyond a point. A methodological contribution of this paper is the use of statistical methods such as analysis of variance (ANOVA), to characterize the interaction between the protocols

  13. A time-slotted on-demand routing protocol for mobile ad hoc unmanned vehicle systems

    NASA Astrophysics Data System (ADS)

    Forsmann, J. Hope; Hiromoto, Robert E.; Svoboda, John

    2007-04-01

    Successful deployment of Unmanned Vehicle Systems (UVS) in military operations has increased their popularity and utility. The ability to sustain reliable mobile ad hoc formations dramatically enhances the usefulness and performance of UVS. Formation movement increases the amount of ground coverage in less time, decreases fuel consumption of the individual nodes, and provides an avenue for mission expansion through cooperative maneuvers such as refueling. In this paper, we study the wireless communication demands that arise from formation and maintenance of UVS within the context of a mobile ad hoc network (MANET). A MANET in formation is typically characterized by tradeoffs between network congestion and the ability to maintain useable communication bandwidth. Maintenance of UVS formations requires each node in the network to be peer-aware, which places a heavy demand on inner node communication. In order to mitigate the inner node network congestion, we introduce a time-slotted communication protocol. The protocol assigns time-slots and allows the designated nodes to communicate directly with other peer-nodes. This approach has been introduced within the context of the Time-Slotted Aloha protocol for station-to-station communication. The approach taken here is to embed the time-slotted reservation protocol into a standard on-demand routing protocol to also address the need to reactively and proactively respond to formation maintenance. The time-slotted on-demand routing protocol is shown to eliminate collisions due to route determination and, therefore, enhance quality of service as well as ensure necessary support for formation movement. A worst-case scenario is described and simulations performed to comparatively demonstrate the advantages of the new protocol.

  14. Performance Analysis of Ad Hoc Routing Protocols in City Scenario for VANET

    NASA Astrophysics Data System (ADS)

    Das, Sanjoy; Raw, Ram Shringar; Das, Indrani

    2011-12-01

    In this paper, performance analysis of Location Aided Routing (LAR), AODV and DSR protocol in city scenarios has been done. The mobility model considered is Manhattan model. This mobility model used to emulate the movement pattern of nodes i.e., vehicles on streets defined by maps. Our objective is to provide a comparative analysis among LAR, AODV and DSR protocol in city scenarios in Vehicular Ad hoc Networks. The simulation work has been conducted using the Glomosim 2.03 simulator. The results show that LAR1 protocol achieves maximum packet delivery ratio is 100% in the sparsely populated network. The delay is maximum in AODV 121.88 ms when the number of node is 10 in the network. The results show that LAR1 outperform DSR and AODV in term of packet delivery ratio and end to end delay.

  15. VehiHealth: An Emergency Routing Protocol for Vehicular Ad Hoc Network to Support Healthcare System.

    PubMed

    Bhoi, S K; Khilar, P M

    2016-03-01

    Survival of a patient depends on effective data communication in healthcare system. In this paper, an emergency routing protocol for Vehicular Ad hoc Network (VANET) is proposed to quickly forward the current patient status information from the ambulance to the hospital to provide pre-medical treatment. As the ambulance takes time to reach the hospital, ambulance doctor can provide sudden treatment to the patient in emergency by sending patient status information to the hospital through the vehicles using vehicular communication. Secondly, the experienced doctors respond to the information by quickly sending a treatment information to the ambulance. In this protocol, data is forwarded through that path which has less link breakage problem between the vehicles. This is done by calculating an intersection value I v a l u e for the neighboring intersections by using the current traffic information. Then the data is forwarded through that intersection which has minimum I v a l u e . Simulation results show VehiHealth performs better than P-GEDIR, GyTAR, A-STAR and GSR routing protocols in terms of average end-to-end delay, number of link breakage, path length, and average response time.

  16. Robust message routing for mobile (wireless) ad hoc networks.

    SciTech Connect

    Goldsby, Michael E.; Johnson, Michael M.; Kilman, Dominique Marie; Bierbaum, Neal Robert; Chen, Helen Y.; Ammerlahn, Heidi R.; Tsang, Rose P.; Nicol, David M.

    2004-01-01

    This report describes the results of research targeting improvements in the robustness of message transport in wireless ad hoc networks. The first section of the report provides an analysis of throughput and latency in the wireless medium access control (MAC) layer and relates the analysis to the commonly used 802.11 protocol. The second section describes enhancements made to several existing models of wireless MAC and ad hoc routing protocols; the models were used in support of the work described in the following section. The third section of the report presents a lightweight transport layer protocol that is superior to TCP for use in wireless networks. In addition, it introduces techniques that improve the performance of any ad hoc source routing protocol. The fourth section presents a novel, highly scalable ad hoc routing protocol that is based on geographic principles but requires no localization hardware.

  17. Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks.

    PubMed

    Hu, Miao; Zhong, Zhangdui; Ni, Minming; Baiocchi, Andrea

    2016-11-01

    Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors' best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well.

  18. Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks

    PubMed Central

    Hu, Miao; Zhong, Zhangdui; Ni, Minming; Baiocchi, Andrea

    2016-01-01

    Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well. PMID:27809285

  19. A Time-Slotted On-Demand Routing Protocol for Mobile Ad Hoc Unmanned Vehicle Systems

    SciTech Connect

    Hope Forsmann; Robert Hiromoto; John Svoboda

    2007-04-01

    The popularity of UAVs has increased dramatically because of their successful deployment in military operations, their ability to preserve human life, and the continual improvements in wireless communication that serves to increase their capabilities. We believe the usefulness of UAVs would be dramatically increased if formation flight were added to the list of capabilities. Currently, sustained formation flight with a cluster of UAVs has only been achieved with two nodes by the Multi-UAV Testbed at the Massachusetts Institute of Technology. (Park, 2004) Formation flight is a complex operation requiring the ability to adjust the flight patterns on the fly and correct for wind gusts, terrain, and differences in node equipment. All of which increases the amount of inner node communication. Since one of the problems with MANET communication is network congestion, we believe a first step towards formation flight can be made through improved inner node communication. We have investigated current communication routing protocols and developed an altered hybrid routing protocol in order to provide communication with less network congestion.

  20. A Performance Analysis of the Optimized Link State Routing Protocol Using Voice Traffic Over Mobile Ad Hoc Networks

    DTIC Science & Technology

    2012-03-22

    audio codec is best suited for MANETS. The MANET simulation environment is established using OPNET . Varying combinations of workloads are submitted...Appendix A. OPNET Simulation Setup .......................................................................... 69 A.1 Scenario Creation and Setup...6. OPNET Ad Hoc Node Wireless Suite Configuration ................................................. 44 7. OPNET OLSR Protocol Configuration

  1. A Multi-User Game-Theoretical Multipath Routing Protocol to Send Video-Warning Messages over Mobile Ad Hoc Networks

    PubMed Central

    Mezher, Ahmad Mohamad; Igartua, Mónica Aguilar; de la Cruz Llopis, Luis J.; Segarra, Esteve Pallarès; Tripp-Barba, Carolina; Urquiza-Aguiar, Luis; Forné, Jordi; Gargallo, Emilio Sanvicente

    2015-01-01

    The prevention of accidents is one of the most important goals of ad hoc networks in smart cities. When an accident happens, dynamic sensors (e.g., citizens with smart phones or tablets, smart vehicles and buses, etc.) could shoot a video clip of the accident and send it through the ad hoc network. With a video message, the level of seriousness of the accident could be much better evaluated by the authorities (e.g., health care units, police and ambulance drivers) rather than with just a simple text message. Besides, other citizens would be rapidly aware of the incident. In this way, smart dynamic sensors could participate in reporting a situation in the city using the ad hoc network so it would be possible to have a quick reaction warning citizens and emergency units. The deployment of an efficient routing protocol to manage video-warning messages in mobile Ad hoc Networks (MANETs) has important benefits by allowing a fast warning of the incident, which potentially can save lives. To contribute with this goal, we propose a multipath routing protocol to provide video-warning messages in MANETs using a novel game-theoretical approach. As a base for our work, we start from our previous work, where a 2-players game-theoretical routing protocol was proposed to provide video-streaming services over MANETs. In this article, we further generalize the analysis made for a general number of N players in the MANET. Simulations have been carried out to show the benefits of our proposal, taking into account the mobility of the nodes and the presence of interfering traffic.Finally, we also have tested our approach in a vehicular ad hoc network as an incipient start point to develop a novel proposal specifically designed for VANETs. PMID:25897496

  2. A Multi-User Game-Theoretical Multipath Routing Protocol to Send Video-Warning Messages over Mobile Ad Hoc Networks.

    PubMed

    Mezher, Ahmad Mohamad; Igartua, Mónica Aguilar; de la Cruz Llopis, Luis J; Pallarès Segarra, Esteve; Tripp-Barba, Carolina; Urquiza-Aguiar, Luis; Forné, Jordi; Sanvicente Gargallo, Emilio

    2015-04-17

    The prevention of accidents is one of the most important goals of ad hoc networks in smart cities. When an accident happens, dynamic sensors (e.g., citizens with smart phones or tablets, smart vehicles and buses, etc.) could shoot a video clip of the accident and send it through the ad hoc network. With a video message, the level of seriousness of the accident could be much better evaluated by the authorities (e.g., health care units, police and ambulance drivers) rather than with just a simple text message. Besides, other citizens would be rapidly aware of the incident. In this way, smart dynamic sensors could participate in reporting a situation in the city using the ad hoc network so it would be possible to have a quick reaction warning citizens and emergency units. The deployment of an efficient routing protocol to manage video-warning messages in mobile Ad hoc Networks (MANETs) has important benefits by allowing a fast warning of the incident, which potentially can save lives. To contribute with this goal, we propose a multipath routing protocol to provide video-warning messages in MANETs using a novel game-theoretical approach. As a base for our work, we start from our previous work, where a 2-players game-theoretical routing protocol was proposed to provide video-streaming services over MANETs. In this article, we further generalize the analysis made for a general number of N players in the MANET. Simulations have been carried out to show the benefits of our proposal, taking into account the mobility of the nodes and the presence of interfering traffic. Finally, we also have tested our approach in a vehicular ad hoc network as an incipient start point to develop a novel proposal specifically designed for VANETs.

  3. Auto-configuration protocols in mobile ad hoc networks.

    PubMed

    Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

    2011-01-01

    The TCP/IP protocol allows the different nodes in a network to communicate by associating a different IP address to each node. In wired or wireless networks with infrastructure, we have a server or node acting as such which correctly assigns IP addresses, but in mobile ad hoc networks there is no such centralized entity capable of carrying out this function. Therefore, a protocol is needed to perform the network configuration automatically and in a dynamic way, which will use all nodes in the network (or part thereof) as if they were servers that manage IP addresses. This article reviews the major proposed auto-configuration protocols for mobile ad hoc networks, with particular emphasis on one of the most recent: D2HCP. This work also includes a comparison of auto-configuration protocols for mobile ad hoc networks by specifying the most relevant metrics, such as a guarantee of uniqueness, overhead, latency, dependency on the routing protocol and uniformity.

  4. Protocols for Detection and Removal of Wormholes for Secure Routing and Neighborhood Creation in Wireless Ad Hoc Networks

    ERIC Educational Resources Information Center

    Hayajneh, Thaier Saleh

    2009-01-01

    Wireless ad hoc networks are suitable and sometimes the only solution for several applications. Many applications, particularly those in military and critical civilian domains (such as battlefield surveillance and emergency rescue) require that ad hoc networks be secure and stable. In fact, security is one of the main barriers to the extensive use…

  5. Auto-Configuration Protocols in Mobile Ad Hoc Networks

    PubMed Central

    Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

    2011-01-01

    The TCP/IP protocol allows the different nodes in a network to communicate by associating a different IP address to each node. In wired or wireless networks with infrastructure, we have a server or node acting as such which correctly assigns IP addresses, but in mobile ad hoc networks there is no such centralized entity capable of carrying out this function. Therefore, a protocol is needed to perform the network configuration automatically and in a dynamic way, which will use all nodes in the network (or part thereof) as if they were servers that manage IP addresses. This article reviews the major proposed auto-configuration protocols for mobile ad hoc networks, with particular emphasis on one of the most recent: D2HCP. This work also includes a comparison of auto-configuration protocols for mobile ad hoc networks by specifying the most relevant metrics, such as a guarantee of uniqueness, overhead, latency, dependency on the routing protocol and uniformity. PMID:22163814

  6. Performance Improvement in Geographic Routing for Vehicular Ad Hoc Networks

    PubMed Central

    Kaiwartya, Omprakash; Kumar, Sushil; Lobiyal, D. K.; Abdullah, Abdul Hanan; Hassan, Ahmed Nazar

    2014-01-01

    Geographic routing is one of the most investigated themes by researchers for reliable and efficient dissemination of information in Vehicular Ad Hoc Networks (VANETs). Recently, different Geographic Distance Routing (GEDIR) protocols have been suggested in the literature. These protocols focus on reducing the forwarding region towards destination to select the Next Hop Vehicles (NHV). Most of these protocols suffer from the problem of elevated one-hop link disconnection, high end-to-end delay and low throughput even at normal vehicle speed in high vehicle density environment. This paper proposes a Geographic Distance Routing protocol based on Segment vehicle, Link quality and Degree of connectivity (SLD-GEDIR). The protocol selects a reliable NHV using the criteria segment vehicles, one-hop link quality and degree of connectivity. The proposed protocol has been simulated in NS-2 and its performance has been compared with the state-of-the-art protocols: P-GEDIR, J-GEDIR and V-GEDIR. The empirical results clearly reveal that SLD-GEDIR has lower link disconnection and end-to-end delay, and higher throughput as compared to the state-of-the-art protocols. It should be noted that the performance of the proposed protocol is preserved irrespective of vehicle density and speed. PMID:25429415

  7. Performance improvement in geographic routing for Vehicular Ad Hoc Networks.

    PubMed

    Kaiwartya, Omprakash; Kumar, Sushil; Lobiyal, D K; Abdullah, Abdul Hanan; Hassan, Ahmed Nazar

    2014-11-25

    Geographic routing is one of the most investigated themes by researchers for reliable and efficient dissemination of information in Vehicular Ad Hoc Networks (VANETs). Recently, different Geographic Distance Routing (GEDIR) protocols have been suggested in the literature. These protocols focus on reducing the forwarding region towards destination to select the Next Hop Vehicles (NHV). Most of these protocols suffer from the problem of elevated one-hop link disconnection, high end-to-end delay and low throughput even at normal vehicle speed in high vehicle density environment. This paper proposes a Geographic Distance Routing protocol based on Segment vehicle, Link quality and Degree of connectivity (SLD-GEDIR). The protocol selects a reliable NHV using the criteria segment vehicles, one-hop link quality and degree of connectivity. The proposed protocol has been simulated in NS-2 and its performance has been compared with the state-of-the-art protocols: P-GEDIR, J-GEDIR and V-GEDIR. The empirical results clearly reveal that SLD-GEDIR has lower link disconnection and end-to-end delay, and higher throughput as compared to the state-of-the-art protocols. It should be noted that the performance of the proposed protocol is preserved irrespective of vehicle density and speed.

  8. A Performance Comparison of Stability, Load-Balancing and Power-Aware Routing Protocols for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-06-01

    mostly attributed to the unfairness of node usage. References [1] J. Broch , D. A. Maltz, D. B. Johnson, Y. C. Hu and J. Jetcheva, “A Performance...Wireless Networks & Mobile Computing, pp. 71 – 78, April 2000. [5] D. B. Johnson, D. A. Maltz, and J. Broch , “DSR: The Dynamic Source Routing

  9. Analysis of location-aware QoS-routing protocols based on partial temporal and spatial topology for real-time multimedia in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2004-08-01

    In the distributed operations of route discovery and maintenance, strong interaction occurs across mobile ad hoc network (MANET) protocol layers in the transport of service packets between source and destination nodes. Quality of service (QoS) requirements are specified for multimedia service classes by the application layer. Due to node mobility, knowledge of their locations is inherently incomplete. Network topology is thus only partially known in time and in space. Cross-layer interactions in the protocol are modeled in terms of a set of concatenated design parameters, updates on node positions and associated energy costs. Functional dependencies of the QoS metrics on the concatenated parameters are described. An analytical framework is established for development of new cross-layer designs that optimize layer interdependencies to achieve the "best" QoS available in the MANET given a partially known, time-varying topology. The designs, based on a reactive MANET protocol, adapt provisioned QoS to dynamic network conditions and residual energy capacities. Cross-layer optimization, given partially known topology, is based on stochastic dynamic programming and predictive estimation conditions derived from time-dependent models of MANET behavior. Models of real-time behavior are based on the control of conditional rates of multivariate point processes (MVPPs). These rates depend on the concatenated protocol and resource parameters. The analytical framework supports predictive models to estimate node mobility in addition to measurement-based estimates of probability distributions for voice, video, data, and other Internet traffic. Estimates of QoS metrics are given in terms of recursive stochastic filters of the network state, based on complete or partial observations of topology and events.

  10. Reliable on-demand multicast routing with congestion control in wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Tang, Ken; Gerla, Mario

    2001-07-01

    In this paper, we address the congestion control multicast routing problem in wireless ad hoc networks through the medium access control (MAC) layer. We first introduce the Broadcast Medium Window (BMW) MAC protocol, which provides reliable delivery to broadcast packets at the MAC layer. We then extend the wireless On-Demand Multicast Routing Protocol (ODMRP) to facilitate congestion control in ad hoc networks using BMW. Through simulation, we show that ODMRP with congestion control adapts well to multicast sources that are aggressive in data transmissions.

  11. Fuzzy Multiple Metrics Link Assessment for Routing in Mobile Ad-Hoc Network

    NASA Astrophysics Data System (ADS)

    Soo, Ai Luang; Tan, Chong Eng; Tay, Kai Meng

    2011-06-01

    In this work, we investigate on the use of Sugeno fuzzy inference system (FIS) in route selection for mobile Ad-Hoc networks (MANETs). Sugeno FIS is introduced into Ad-Hoc On Demand Multipath Distance Vector (AOMDV) routing protocol, which is derived from its predecessor, Ad-Hoc On Demand Distance Vector (AODV). Instead of using the conventional way that considering only a single metric to choose the best route, our proposed fuzzy decision making model considers up to three metrics. In the model, the crisp inputs of the three parameters are fed into an FIS and being processed in stages, i.e., fuzzification, inference, and defuzzification. Finally, after experiencing all the stages, a single value score is generated from the combination metrics, which will be used to measure all the discovered routes credibility. Results obtained from simulations show a promising improvement as compared to AOMDV and AODV.

  12. MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

    PubMed Central

    Elizarraras, Omar; Panduro, Marco; Méndez, Aldo L.

    2014-01-01

    The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput. PMID:25140339

  13. Decentralized session initiation protocol solution in ad hoc networks

    NASA Astrophysics Data System (ADS)

    Han, Lu; Jin, Zhigang; Shu, Yantai; Dong, Linfang

    2006-10-01

    With the fast development of ad hoc networks, SIP has attracted more and more attention in multimedia service. This paper proposes a new architecture to provide SIP service for ad hoc users, although there is no centralized SIP server deployed. In this solution, we provide the SIP service by the introduction of two nodes: Designated SIP Server (DS) and its Backup Server (BDS). The nodes of ad hoc network designate DS and BDS when they join the session nodes set and when some pre-defined events occur. A new sip message type called REGISTRAR is presented so nodes can send others REGISTRAR message to declare they want to be DS. According to the IP information taken in the message, an algorithm works like the election of DR and BDR in OSPF protocol is used to vote DS and BDS SIP servers. Naturally, the DS will be replaced by BDS when the DS is down for predicable or unpredictable reasons. To facilitate this, the DS should register to the BDS and transfer a backup of the SIP users' database. Considering the possibility DS or BDS may abruptly go down, a special policy is given. When there is no DS and BDS, a new election procedure is triggered just like the startup phase. The paper also describes how SIP works normally in the decentralized model as well as the evaluation of its performance. All sessions based on SIP in ad hoc such as DS voting have been tested in the real experiments within a 500m*500m square area where about 30 random nodes are placed.

  14. A Dirichlet reputation system in reliable routing of wireless ad hoc network

    SciTech Connect

    Yang, Dr. Li; Cui, Xiaohui; Cemerlic, Alma

    2010-01-01

    Ad hoc networks are very helpful in situations when no fixed network infrastructure is available, such as natural disasters and military conflicts. In such a network, all wireless nodes are equal peers simultaneously serving as both senders and routers for other nodes. Therefore, how to route packets through reliable paths becomes a fundamental problems when behaviors of certain nodes deviate from wireless ad hoc routing protocols. We proposed a novel Dirichlet reputation model based on Bayesian inference theory which evaluates reliability of each node in terms of packet delivery. Our system offers a way to predict and select a reliable path through combination of first-hand observation and second-hand reputation reports. We also proposed moving window mechanism which helps to adjust ours responsiveness of our system to changes of node behaviors. We integrated the Dirichlet reputation into routing protocol of wireless ad hoc networks. Our extensive simulation indicates that our proposed reputation system can improve good throughput of the network and reduce negative impacts caused by misbehaving nodes.

  15. Effective Route Maintenance and Restoration Schemes in Mobile Ad Hoc Networks

    PubMed Central

    Kang, Byung-Seok; Ko, In-Young

    2010-01-01

    This study proposes a location-based hybrid routing protocol to improve data packet delivery and to reduce control message overhead in mobile ad hoc networks. In mobile environments, where nodes move continuously at a high speed, it is generally difficult to maintain and restore route paths. Therefore, this study suggests a new flooding mechanism to control route paths. The essence of the proposed scheme is its effective tracking of the destination’s location based on the beacon messages of the main route nodes. Through experiments based on an NS-2 simulator, the proposed scheme shows improvements in the data packet delivery ratio and reduces the amount of routing control message overhead compared with existing routing protocols such as AODV, LAR, ZRP and AODV-DFR. PMID:22315570

  16. Analysis of a distributed algorithm to determine multiple routes with path diversity in ad hoc networks.

    SciTech Connect

    Ghosal, Dipak; Mueller, Stephen Ng

    2005-04-01

    With multipath routing in mobile ad hoc networks (MANETs), a source can establish multiple routes to a destination for routing data. In MANETs, mulitpath routing can be used to provide route resilience, smaller end-to-end delay, and better load balancing. However, when the multiple paths are close together, transmissions of different paths may interfere with each other, causing degradation in performance. Besides interference, the physical diversity of paths also improves fault tolerance. We present a purely distributed multipath protocol based on the AODV-Multipath (AODVM) protocol called AODVM with Path Diversity (AODVM/PD) that finds multiple paths with a desired degree of correlation between paths specified as an input parameter to the algorithm. We demonstrate through detailed simulation analysis that multiple paths with low degree of correlation determined by AODVM/PD provides both smaller end-to-end delay than AODVM in networks with low mobility and better route resilience in the presence of correlated node failures.

  17. Adaptation of mobile ad-hoc network protocols for sensor networks to vehicle control applications

    NASA Astrophysics Data System (ADS)

    Sato, Kenya; Matsui, Yosuke; Koita, Takahiro

    2005-12-01

    As sensor network applications to monitor and control the physical environment from remote locations, a mobile ad-hoc network (MANET) has been the focus of many recent research and development efforts. A MANET, autonomous system of mobile hosts, is characterized by multi-hop wireless links, absence of any cellular infrastructure, and frequent host mobility. Many kinds of routing protocols for ad-hoc network have been proposed and still actively updated, because each application has different characteristics and requirements. Since the current studies show it is almost impossible to design an efficient routing protocol to be adapted for all kinds of applications. We, therefore, have focused a certain application, inter-vehicle communication for ITS (Intelligent Transport Systems), to evaluate the routing protocols. In our experiment, we defined several traffic flow models for inter-vehicle communication applications. By using simulation, we evaluated end-to-end delay and throughput performance of data transmission for inter-vehicle communications with the existing routing protocols. The result confirms the feasibility of using some routing protocols for inter-vehicle communication services.

  18. Effects of Data Replication on Data Exfiltration in Mobile Ad Hoc Networks Utilizing Reactive Protocols

    DTIC Science & Technology

    2015-03-01

    IN MOBILE AD HOC NETWORKS UTILIZING REACTIVE PROTOCOLS THESIS Presented to the Faculty Department of Electrical and Computer Engineering Graduate...EFFECTS OF DATA REPLICATION ON DATA EXFILTRATION IN MOBILE AD HOC NETWORKS UTILIZING REACTIVE PROTOCOLS THESIS Corey T. Willinger, Captain, USAF AFIT...APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENG-MS-15-M-035 EFFECTS OF DATA REPLICATION ON DATA EXFILTRATION IN MOBILE AD HOC NETWORKS

  19. A Token Ring Protocol for Dynamic Ad-hoc Wireless Environments

    SciTech Connect

    Top, P; Kohlhepp, V; Dowla, F

    2005-09-30

    A wireless ad-hoc networking protocol is presented. The protocol is designed to be flexible, easy to use and adaptable to a wide variety of potential applications. The primary considerations in design are small code size, guaranteed bandwidth access, limited delay, and error resilience in a highly dynamic ad-hoc environment. These considerations are achieved through the use of token ring protocol.

  20. Energy Efficient Link Aware Routing with Power Control in Wireless Ad Hoc Networks

    PubMed Central

    Katiravan, Jeevaa; Sylvia, D.; Rao, D. Srinivasa

    2015-01-01

    In wireless ad hoc networks, the traditional routing protocols make the route selection based on minimum distance between the nodes and the minimum number of hop counts. Most of the routing decisions do not consider the condition of the network such as link quality and residual energy of the nodes. Also, when a link failure occurs, a route discovery mechanism is initiated which incurs high routing overhead. If the broadcast nature and the spatial diversity of the wireless communication are utilized efficiently it becomes possible to achieve improvement in the performance of the wireless networks. In contrast to the traditional routing scheme which makes use of a predetermined route for packet transmission, such an opportunistic routing scheme defines a predefined forwarding candidate list formed by using single network metrics. In this paper, a protocol is proposed which uses multiple metrics such as residual energy and link quality for route selection and also includes a monitoring mechanism which initiates a route discovery for a poor link, thereby reducing the overhead involved and improving the throughput of the network while maintaining network connectivity. Power control is also implemented not only to save energy but also to improve the network performance. Using simulations, we show the performance improvement attained in the network in terms of packet delivery ratio, routing overhead, and residual energy of the network. PMID:26167529

  1. Energy Efficient Link Aware Routing with Power Control in Wireless Ad Hoc Networks.

    PubMed

    Katiravan, Jeevaa; Sylvia, D; Rao, D Srinivasa

    2015-01-01

    In wireless ad hoc networks, the traditional routing protocols make the route selection based on minimum distance between the nodes and the minimum number of hop counts. Most of the routing decisions do not consider the condition of the network such as link quality and residual energy of the nodes. Also, when a link failure occurs, a route discovery mechanism is initiated which incurs high routing overhead. If the broadcast nature and the spatial diversity of the wireless communication are utilized efficiently it becomes possible to achieve improvement in the performance of the wireless networks. In contrast to the traditional routing scheme which makes use of a predetermined route for packet transmission, such an opportunistic routing scheme defines a predefined forwarding candidate list formed by using single network metrics. In this paper, a protocol is proposed which uses multiple metrics such as residual energy and link quality for route selection and also includes a monitoring mechanism which initiates a route discovery for a poor link, thereby reducing the overhead involved and improving the throughput of the network while maintaining network connectivity. Power control is also implemented not only to save energy but also to improve the network performance. Using simulations, we show the performance improvement attained in the network in terms of packet delivery ratio, routing overhead, and residual energy of the network.

  2. Reinforcement learning for routing in cognitive radio ad hoc networks.

    PubMed

    Al-Rawi, Hasan A A; Yau, Kok-Lim Alvin; Mohamad, Hafizal; Ramli, Nordin; Hashim, Wahidah

    2014-01-01

    Cognitive radio (CR) enables unlicensed users (or secondary users, SUs) to sense for and exploit underutilized licensed spectrum owned by the licensed users (or primary users, PUs). Reinforcement learning (RL) is an artificial intelligence approach that enables a node to observe, learn, and make appropriate decisions on action selection in order to maximize network performance. Routing enables a source node to search for a least-cost route to its destination node. While there have been increasing efforts to enhance the traditional RL approach for routing in wireless networks, this research area remains largely unexplored in the domain of routing in CR networks. This paper applies RL in routing and investigates the effects of various features of RL (i.e., reward function, exploitation, and exploration, as well as learning rate) through simulation. New approaches and recommendations are proposed to enhance the features in order to improve the network performance brought about by RL to routing. Simulation results show that the RL parameters of the reward function, exploitation, and exploration, as well as learning rate, must be well regulated, and the new approaches proposed in this paper improves SUs' network performance without significantly jeopardizing PUs' network performance, specifically SUs' interference to PUs.

  3. Reinforcement Learning for Routing in Cognitive Radio Ad Hoc Networks

    PubMed Central

    Al-Rawi, Hasan A. A.; Mohamad, Hafizal; Hashim, Wahidah

    2014-01-01

    Cognitive radio (CR) enables unlicensed users (or secondary users, SUs) to sense for and exploit underutilized licensed spectrum owned by the licensed users (or primary users, PUs). Reinforcement learning (RL) is an artificial intelligence approach that enables a node to observe, learn, and make appropriate decisions on action selection in order to maximize network performance. Routing enables a source node to search for a least-cost route to its destination node. While there have been increasing efforts to enhance the traditional RL approach for routing in wireless networks, this research area remains largely unexplored in the domain of routing in CR networks. This paper applies RL in routing and investigates the effects of various features of RL (i.e., reward function, exploitation, and exploration, as well as learning rate) through simulation. New approaches and recommendations are proposed to enhance the features in order to improve the network performance brought about by RL to routing. Simulation results show that the RL parameters of the reward function, exploitation, and exploration, as well as learning rate, must be well regulated, and the new approaches proposed in this paper improves SUs' network performance without significantly jeopardizing PUs' network performance, specifically SUs' interference to PUs. PMID:25140350

  4. Secure and Fair Cluster Head Selection Protocol for Enhancing Security in Mobile Ad Hoc Networks

    PubMed Central

    Paramasivan, B.; Kaliappan, M.

    2014-01-01

    Mobile ad hoc networks (MANETs) are wireless networks consisting of number of autonomous mobile devices temporarily interconnected into a network by wireless media. MANETs become one of the most prevalent areas of research in the recent years. Resource limitations, energy efficiency, scalability, and security are the great challenging issues in MANETs. Due to its deployment nature, MANETs are more vulnerable to malicious attack. The secure routing protocols perform very basic security related functions which are not sufficient to protect the network. In this paper, a secure and fair cluster head selection protocol (SFCP) is proposed which integrates security factors into the clustering approach for achieving attacker identification and classification. Byzantine agreement based cooperative technique is used for attacker identification and classification to make the network more attack resistant. SFCP used to solve this issue by making the nodes that are totally surrounded by malicious neighbors adjust dynamically their belief and disbelief thresholds. The proposed protocol selects the secure and energy efficient cluster head which acts as a local detector without imposing overhead to the clustering performance. SFCP is simulated in network simulator 2 and compared with two protocols including AODV and CBRP. PMID:25143986

  5. Secure and fair cluster head selection protocol for enhancing security in mobile ad hoc networks.

    PubMed

    Paramasivan, B; Kaliappan, M

    2014-01-01

    Mobile ad hoc networks (MANETs) are wireless networks consisting of number of autonomous mobile devices temporarily interconnected into a network by wireless media. MANETs become one of the most prevalent areas of research in the recent years. Resource limitations, energy efficiency, scalability, and security are the great challenging issues in MANETs. Due to its deployment nature, MANETs are more vulnerable to malicious attack. The secure routing protocols perform very basic security related functions which are not sufficient to protect the network. In this paper, a secure and fair cluster head selection protocol (SFCP) is proposed which integrates security factors into the clustering approach for achieving attacker identification and classification. Byzantine agreement based cooperative technique is used for attacker identification and classification to make the network more attack resistant. SFCP used to solve this issue by making the nodes that are totally surrounded by malicious neighbors adjust dynamically their belief and disbelief thresholds. The proposed protocol selects the secure and energy efficient cluster head which acts as a local detector without imposing overhead to the clustering performance. SFCP is simulated in network simulator 2 and compared with two protocols including AODV and CBRP.

  6. Modelling of Medium Access Control (MAC) Protocols for Mobile Ad-Hoc Networks

    DTIC Science & Technology

    2005-06-01

    Slot IP Internet Protocol LAN Local Area Network MAC Medium Access Control MACAW Medium Access Protocol for Wireless LANs MANET Mobile Ad-hoc...Unforced state – It waits after entering the state until it is invoked by another process or an interrupt. It is in dark grey on this report, and red ... green in OPNET. A MAC process model is built for general initialisations of the MAC module, and to invoke the selected MAC protocol process model

  7. Adaptive Demand-Driven Multicast Routing in Multi-Hop Wireless Ad Hoc Networks

    DTIC Science & Technology

    2004-05-06

    16] L. Ji and M. S. Corson . A Lightweight Adaptive Multicast Algorithm. In Proceedings of IEEE GLOBECOM ’98, pages 1036–1042, December 1998. [17] L...Ji and M. S. Corson . Differential Destination Multicast (DDM) Specification. Internet- Draft, draft-ietf-manet-ddm-00.txt, July 2000. Work in...3 [30] Charles E. Perkins, Elizabeth M. Royer, and Samir R. Das. Ad Hoc On Demand Distance Vector (AODV) Routing. Internet-Draft, draft-ietf-manet

  8. Dynamic autonomous routing technology for IP-based satellite ad hoc networks

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofei; Deng, Jing; Kostas, Theresa; Rajappan, Gowri

    2014-06-01

    IP-based routing for military LEO/MEO satellite ad hoc networks is very challenging due to network and traffic heterogeneity, network topology and traffic dynamics. In this paper, we describe a traffic priority-aware routing scheme for such networks, namely Dynamic Autonomous Routing Technology (DART) for satellite ad hoc networks. DART has a cross-layer design, and conducts routing and resource reservation concurrently for optimal performance in the fluid but predictable satellite ad hoc networks. DART ensures end-to-end data delivery with QoS assurances by only choosing routing paths that have sufficient resources, supporting different packet priority levels. In order to do so, DART incorporates several resource management and innovative routing mechanisms, which dynamically adapt to best fit the prevailing conditions. In particular, DART integrates a resource reservation mechanism to reserve network bandwidth resources; a proactive routing mechanism to set up non-overlapping spanning trees to segregate high priority traffic flows from lower priority flows so that the high priority flows do not face contention from low priority flows; a reactive routing mechanism to arbitrate resources between various traffic priorities when needed; a predictive routing mechanism to set up routes for scheduled missions and for anticipated topology changes for QoS assurance. We present simulation results showing the performance of DART. We have conducted these simulations using the Iridium constellation and trajectories as well as realistic military communications scenarios. The simulation results demonstrate DART's ability to discriminate between high-priority and low-priority traffic flows and ensure disparate QoS requirements of these traffic flows.

  9. A cooperative MAC protocol with error-aware relay selection for wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Liu, Shanzhi; Liu, Kai; Wang, Rui; Fang, Ruochen; Liu, Feng

    2017-01-01

    To solve performance degradation caused by channel fading, we propose a cooperative MAC protocol with error-aware relay selection for wireless ad hoc networks in this paper. In the protocol, the transmission error of data packet caused by channel fading are considered in order to achieve the best cooperative gain in the poor quality channel. In the relay selection process, potential relay nodes satisfying corresponding requirement can compete to sever as final relay node by means of priority selection and collision resolution process. Finally, simulation results show that the proposed protocol outperforms other protocol in terms of packet error rate and the saturation throughput.

  10. Opportunistic Hybrid Transport Protocol (OHTP) for Cognitive Radio Ad Hoc Sensor Networks.

    PubMed

    Bin Zikria, Yousaf; Nosheen, Summera; Ishmanov, Farruh; Kim, Sung Won

    2015-12-15

    The inefficient assignment of spectrum for different communications purposes, plus technology enhancements and ever-increasing usage of wireless technology is causing spectrum scarcity. To address this issue, one of the proposed solutions in the literature is to access the spectrum dynamically or opportunistically. Therefore, the concept of cognitive radio appeared, which opens up a new research paradigm. There is extensive research on the physical, medium access control and network layers. The impact of the transport layer on the performance of cognitive radio ad hoc sensor networks is still unknown/unexplored. The Internet's de facto transport protocol is not well suited to wireless networks because of its congestion control mechanism. We propose an opportunistic hybrid transport protocol for cognitive radio ad hoc sensor networks. We developed a new congestion control mechanism to differentiate true congestion from interruption loss. After such detection and differentiation, we propose methods to handle them opportunistically. There are several benefits to window- and rate-based protocols. To exploit the benefits of both in order to enhance overall system performance, we propose a hybrid transport protocol. We empirically calculate the optimal threshold value to switch between window- and rate-based mechanisms. We then compare our proposed transport protocol to Transmission Control Protocol (TCP)-friendly rate control, TCP-friendly rate control for cognitive radio, and TCP-friendly window-based control. We ran an extensive set of simulations in Network Simulator 2. The results indicate that the proposed transport protocol performs better than all the others.

  11. Energy-Aware Multipath Routing Scheme Based on Particle Swarm Optimization in Mobile Ad Hoc Networks

    PubMed Central

    Robinson, Y. Harold; Rajaram, M.

    2015-01-01

    Mobile ad hoc network (MANET) is a collection of autonomous mobile nodes forming an ad hoc network without fixed infrastructure. Dynamic topology property of MANET may degrade the performance of the network. However, multipath selection is a great challenging task to improve the network lifetime. We proposed an energy-aware multipath routing scheme based on particle swarm optimization (EMPSO) that uses continuous time recurrent neural network (CTRNN) to solve optimization problems. CTRNN finds the optimal loop-free paths to solve link disjoint paths in a MANET. The CTRNN is used as an optimum path selection technique that produces a set of optimal paths between source and destination. In CTRNN, particle swarm optimization (PSO) method is primly used for training the RNN. The proposed scheme uses the reliability measures such as transmission cost, energy factor, and the optimal traffic ratio between source and destination to increase routing performance. In this scheme, optimal loop-free paths can be found using PSO to seek better link quality nodes in route discovery phase. PSO optimizes a problem by iteratively trying to get a better solution with regard to a measure of quality. The proposed scheme discovers multiple loop-free paths by using PSO technique. PMID:26819966

  12. Linear QoS goals of additive and concave metrics in ad hoc cognitive packet routing.

    PubMed

    Lent, Ricardo

    2006-12-01

    This paper addresses two scalability problems related to the cognitive map of packets in ad hoc cognitive packet networks and proposes a solution. Previous works have included latency as part of the routing goal of smart packets, which requires packets to collect their arrival time at each node in a path. Such a requirement resulted in a packet overhead proportional to the path length. The second problem is that the multiplicative form of path availability, which was employed to measure resources, loses accuracy in long paths. To solve these problems, new goals are proposed in this paper. These goals are linear functions of low-overhead metrics and can provide similar performance results with lower cost. One direct result shown in simulation is that smart packets driven by a linear function of path length and buffer occupancy can effectively balance the traffic of multiple flows without the large overhead that would be needed if round-trip delay was used. In addition, energy-aware routing is also studied under this scheme as well as link selection based on their expected level of security.

  13. Developing a Conceptual Unmanned Aerial Vehicle Communications Mobile AD Hoc Network Simulation Model

    DTIC Science & Technology

    2002-06-01

    Elizabeth Royer described the Ad Hoc On-Demand Distance Vector (AODV) routing protocol as “providing quick and efficient route establishment between...Network.” Thesis, Naval Postgraduate School, December 2000. 8. Das, Samir R., Perkins, Charles E., and Royer, Elizabeth M. “ The Ad-hoc On-Demand...Lidong. “Securing Ad Hoc Networks.” Paper Cornell University, Itaca, New York, NY. 16. Corson , Scott S., and Macker, J. “Mobile Ad Hoc

  14. Enhanced Weight based DSR for Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Verma, Samant; Jain, Sweta

    2011-12-01

    Routing in ad hoc network is a great problematic, since a good routing protocol must ensure fast and efficient packet forwarding, which isn't evident in ad hoc networks. In literature there exists lot of routing protocols however they don't include all the aspects of ad hoc networks as mobility, device and medium constraints which make these protocols not efficient for some configuration and categories of ad hoc networks. Thus in this paper we propose an improvement of Weight Based DSR in order to include some of the aspects of ad hoc networks as stability, remaining battery power, load and trust factor and proposing a new approach Enhanced Weight Based DSR.

  15. PNNI routing support for ad hoc mobile networking: A flat architecture

    SciTech Connect

    Martinez, L.; Sholander, P.; Tolendino, L.

    1997-12-01

    This contribution extends the Outside Nodal Hierarchy List (ONHL) procedures described in ATM Form Contribution 97-0766. These extensions allow multiple mobile networks to form either an ad hoc network or an extension of a fixed PNNI infrastructure. This contribution covers the simplest case where the top-most Logical Group Nodes (LGNs), in those mobile networks, all reside at the same level in a PNNI hierarchy. Future contributions will cover the general case where those top-most LGNs reside at different hierarchy levels. This contribution considers a flat ad hoc network architecture--in the sense that each mobile network always participates in the PNNI hierarchy at the preconfigured level of its top-most LGN.

  16. PNNI routing support for ad hoc mobile networking: The multilevel case

    SciTech Connect

    Martinez, L.; Sholander, P.; Tolendino, L.

    1998-01-01

    This contribution extends the Outside Nodal Hierarchy List (ONHL) procedures described in ATM Forum Contributions 97-0766 and 97-0933. These extensions allow multiple mobile networks to form either an ad hoc network or an extension of a fixed PNNI infrastructure. A previous contribution (97-1073) covered the simplest case where the top-most Logical Group Nodes (LGNs), in those mobile networks, all resided at the same level in a PNNI hierarchy. This contribution covers the more general case wherein those top-most LGNs may reside at different PNNI hierarchy levels. Both of the SNL contributions consider flat ad hoc network architectures in the sense that each mobile network always participates in the PNNI hierarchy at the pre-configured level of its top-most LGN.

  17. EFFECT OF MOBILITY ON PERFORMANCE OF WIRELESS AD-HOC NETWORK PROTOCOLS.

    SciTech Connect

    Barrett, C. L.; Drozda, M.; Marathe, M. V.; Marathe, A.

    2001-01-01

    We empirically study the effect of mobility on the performance of protocols designed for wireless adhoc networks. An important ohjective is to study the interaction of the Routing and MAC layer protocols under different mobility parameters. We use three basic mobility models: grid mobility model, random waypoint model, and exponential correlated random model. The performance of protocols was measured in terms of (i) latency, (ii) throughput, (iii) number of packels received, (iv) long term fairness and (v) number of control packets at the MAC layer level. Three different commonly studied routing protocols were used: AODV, DSR and LAR1. Similarly three well known MAC protocols were used: MACA, 802.1 1 and CSMA. The inair1 conclusion of our study include the following: 1. 'I'he performance of the: network varies widely with varying mobility models, packet injection rates and speeds; and can ba in fact characterized as fair to poor depending on the specific situation. Nevertheless, in general, it appears that the combination of AODV and 802.1 I is far better than other combination of routing and MAC protocols. 2. MAC layer protocols interact with routing layer protocols. This concept which is formalized using statistics implies that in general it is not meaningful to speak about a MAC or a routing protocol in isolation. Such an interaction leads to trade-offs between the amount of control packets generated by each layer. More interestingly, the results wise the possibility of improving the performance of a particular MAC layer protocol by using a cleverly designed routing protocol or vice-versa. 3. Routing prolocols with distributed knowledge about routes are more suitable for networks with mobility. This is seen by comparing the performance of AODV with DSR or LAR scheme 1. In DSli and IAR scheme 1, information about a computed path is being stored in the route query control packct. 4. MAC layer protocols have varying performance with varying mobility models. It is

  18. Sender- and Receiver-Initiated Multiple Access Protocols for Ad-Hoc Networks

    DTIC Science & Technology

    2000-12-01

    including MACA [55], MACAW [13], IEEE 802.11 [3], and FAMA [36]. These examples, and most protocols based on collision-avoidance handshakes to date are...used in protocols like MACA [55], MACAW [13] and FAMA [35, 36]. In RIMA with simple polling (RIMA-SP), the receiver sends a Ready-to-Receive (RTR...used the OPNET simulation tool to implement the protocols. Table 2.2 presents the results for RIMA-DP, FAMA-NCS, and MACAW ; the results for MACAW are

  19. Protocol independent adaptive route update for VANET.

    PubMed

    Rasheed, Asim; Ajmal, Sana; Qayyum, Amir

    2014-01-01

    High relative node velocity and high active node density have presented challenges to existing routing approaches within highly scaled ad hoc wireless networks, such as Vehicular Ad hoc Networks (VANET). Efficient routing requires finding optimum route with minimum delay, updating it on availability of a better one, and repairing it on link breakages. Current routing protocols are generally focused on finding and maintaining an efficient route, with very less emphasis on route update. Adaptive route update usually becomes impractical for dense networks due to large routing overheads. This paper presents an adaptive route update approach which can provide solution for any baseline routing protocol. The proposed adaptation eliminates the classification of reactive and proactive by categorizing them as logical conditions to find and update the route.

  20. Protocol Independent Adaptive Route Update for VANET

    PubMed Central

    Rasheed, Asim; Qayyum, Amir

    2014-01-01

    High relative node velocity and high active node density have presented challenges to existing routing approaches within highly scaled ad hoc wireless networks, such as Vehicular Ad hoc Networks (VANET). Efficient routing requires finding optimum route with minimum delay, updating it on availability of a better one, and repairing it on link breakages. Current routing protocols are generally focused on finding and maintaining an efficient route, with very less emphasis on route update. Adaptive route update usually becomes impractical for dense networks due to large routing overheads. This paper presents an adaptive route update approach which can provide solution for any baseline routing protocol. The proposed adaptation eliminates the classification of reactive and proactive by categorizing them as logical conditions to find and update the route. PMID:24723807

  1. Distributed Reinforcement Learning Approach for Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Wu, Celimuge; Kumekawa, Kazuya; Kato, Toshihiko

    In Vehicular Ad hoc Networks (VANETs), general purpose ad hoc routing protocols such as AODV cannot work efficiently due to the frequent changes in network topology caused by vehicle movement. This paper proposes a VANET routing protocol QLAODV (Q-Learning AODV) which suits unicast applications in high mobility scenarios. QLAODV is a distributed reinforcement learning routing protocol, which uses a Q-Learning algorithm to infer network state information and uses unicast control packets to check the path availability in a real time manner in order to allow Q-Learning to work efficiently in a highly dynamic network environment. QLAODV is favored by its dynamic route change mechanism, which makes it capable of reacting quickly to network topology changes. We present an analysis of the performance of QLAODV by simulation using different mobility models. The simulation results show that QLAODV can efficiently handle unicast applications in VANETs.

  2. An Authenticated On-Demand Routing Protocol with Key Exchange for Secure MANET

    NASA Astrophysics Data System (ADS)

    Park, Youngho; Rhee, Kyung-Hyune

    In the meantime, most secure ad hoc routing protocols based on cryptography just have assumed that pair-wise secret keys or public keys were distributed among nodes before running a routing protocol. In this paper, we raise a question about key management related to existing secure routing protocols, and then we propose an authenticated on-demand ad hoc routing protocol with key exchange by applying the ID-based keyed authenticator. In particular, we focus on providing an authentication mechanism to Dynamic Source Routing protocol combined with Diffie-Hellman key exchange protocol, and then we demonstrate simulated performance evaluations. The main contribution of our work is to provide a concurrent establishment of a route and a session key in a secure manner between source and destination nodes in ad hoc networks.

  3. Combining Infrastructure and Ad Hoc Collaboration for Data Management in Mobile Wireless Networks

    DTIC Science & Technology

    2005-01-01

    Elizabeth M. Royer. "Ad hoc On-Demand Distance Vector Routing." Proceedings of the 2nd IEEE Workshop on Mobile Computing Systems and Applications...Charles Perkins, ACM SIGCOMM󈨢 Conference on Communications Architectures, Protocols and Applications 22. Vincent D. Park and M. Scott Corson , A

  4. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-05-01

    Sagnik Ghosh, Bhaskar D. Rao, and James R. Zeidler; "Outage-Efficient Strategies for Multiuser MIMO Networks with Channel Distribution Information... Distributed cooperative routing and hybrid ARQ in MIMO -BLAST ad hoc networks”, submitted to IEEE Transactions on Communications, 2009. Davide...mobile ad hoc networks using polling techniques for MIMO nodes. Centralized and distributed topology control algorithms have been develop to

  5. Realistic Mobility Modeling for Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Akay, Hilal; Tugcu, Tuna

    2009-08-01

    Simulations used for evaluating the performance of routing protocols for Vehicular Ad Hoc Networks (VANET) are mostly based on random mobility and fail to consider individual behaviors of the vehicles. Unrealistic assumptions about mobility produce misleading results about the behavior of routing protocols in real deployments. In this paper, a realistic mobility modeling tool, Mobility for Vehicles (MOVE), which considers the basic mobility behaviors of vehicles, is proposed for a more accurate evaluation. The proposed model is tested against the Random Waypoint (RWP) model using AODV and OLSR protocols. The results show that the mobility model significantly affects the number of nodes within the transmission range of a node, the volume of control traffic, and the number of collisions. It is shown that number of intersections, grid size, and node density are important parameters when dealing with VANET performance.

  6. A novel Smart Routing Protocol for remote health monitoring in Medical Wireless Networks.

    PubMed

    Sundararajan, T V P; Sumithra, M G; Maheswar, R

    2014-01-01

    In a Medical Wireless Network (MWN), sensors constantly monitor patient's physiological condition and movement. Inter-MWN communications are set up between the Patient Server and one or more Centralized Coordinators. However, MWNs require protocols with little energy consumption and the self-organizing attribute perceived in ad-hoc networks. The proposed Smart Routing Protocol (SRP) selects only the nodes with a higher residual energy and lower traffic density for routing. This approach enhances cooperation among the nodes of a Mobile Ad Hoc Network. Consequently, SRP produces better results than the existing protocols, namely Conditional Min-Max Battery Cost Routing, Min-Max Battery Cost Routing and AdHoc On-demand Distance Vector in terms of network parameters. The performance of the erstwhile schemes for routing protocols is evaluated using the network simulator Qualnet v 4.5.

  7. The research of a new adaptive on-demand routing protocol in WSN

    NASA Astrophysics Data System (ADS)

    Zhu, Dongjie; Cui, Gang; Huang, Junheng; Zhang, Zhaoxing

    2013-03-01

    As an important part of the Internet of Things, WSN also has routing strategies which plays a critical role as well as it does in Ad hoc. After the introduction of some distinct traits of WSN, a detailed analysis is performed for a typical ondemand routing protocol in Ad hoc AODV, which then is transplanted into WSN. Furthermore, a transition method of adaptive clustering routing is proposed, based on which, a new adaptive hierarchical routing transition protocol (BCRP) is put forward. Finally, simulations and comparisons of BCRP are performed which lead to a conclusion that BCRP has been greatly improved concerning adaptability and extensibility.

  8. Detecting and isolating malicious nodes in wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Li, Fanzhi; Jassim, Sabah

    2007-04-01

    Malicious nodes can seriously impair the performance of wireless ad hoc networks as a result of different actions such as packet dropping. Secure routes are shortest paths on which every node on the route is trusted even if unknown. Secure route discovery requires the adoption of mechanisms of associating trust to nodes. Most existing secure route discovery mechanisms rely on shared keys and digital signature. In the absence of central nodes that act as certification authority, such protocols suffer from heavy computational burden and are vulnerable to malicious attacks. In this paper we shall review existing techniques for secure routing and propose to complement route finding with creditability scores. Each node would have a credit list for its neighbors. Each node monitors its neighbors' pattern of delivering packets and regularly credits are reviewed and updated accordingly. Unlike most existing schemes the focus of our work is based on post route discovery stage, i.e. when packets are transmitted on discovered routes. The level of trust in any route will be based on the credits associated with the neighbors belonging to the discovered route. We shall evaluate the performance of the proposed scheme by modifying our simulation system so that each node has a dynamic changing "credit list" for its neighbors' behavior. We shall conduct a series of simulations with and without the proposed scheme and compare the results. We will demonstrate that the proposed mechanism is capable of isolating malicious nodes and thereby counteracting black hole attacks.

  9. Cross-Layer Service Discovery Mechanism for OLSRv2 Mobile Ad Hoc Networks

    PubMed Central

    Vara, M. Isabel; Campo, Celeste

    2015-01-01

    Service discovery plays an important role in mobile ad hoc networks (MANETs). The lack of central infrastructure, limited resources and high mobility make service discovery a challenging issue for this kind of network. This article proposes a new service discovery mechanism for discovering and advertising services integrated into the Optimized Link State Routing Protocol Version 2 (OLSRv2). In previous studies, we demonstrated the validity of a similar service discovery mechanism integrated into the previous version of OLSR (OLSRv1). In order to advertise services, we have added a new type-length-value structure (TLV) to the OLSRv2 protocol, called service discovery message (SDM), according to the Generalized MANET Packet/Message Format defined in Request For Comments (RFC) 5444. Each node in the ad hoc network only advertises its own services. The advertisement frequency is a user-configurable parameter, so that it can be modified depending on the user requirements. Each node maintains two service tables, one to store information about its own services and another one to store information about the services it discovers in the network. We present simulation results, that compare our service discovery integrated into OLSRv2 with the one defined for OLSRv1 and with the integration of service discovery in Ad hoc On-demand Distance Vector (AODV) protocol, in terms of service discovery ratio, service latency and network overhead. PMID:26205272

  10. Cross-Layer Service Discovery Mechanism for OLSRv2 Mobile Ad Hoc Networks.

    PubMed

    Vara, M Isabel; Campo, Celeste

    2015-07-20

    Service discovery plays an important role in mobile ad hoc networks (MANETs). The lack of central infrastructure, limited resources and high mobility make service discovery a challenging issue for this kind of network. This article proposes a new service discovery mechanism for discovering and advertising services integrated into the Optimized Link State Routing Protocol Version 2 (OLSRv2). In previous studies, we demonstrated the validity of a similar service discovery mechanism integrated into the previous version of OLSR (OLSRv1). In order to advertise services, we have added a new type-length-value structure (TLV) to the OLSRv2 protocol, called service discovery message (SDM), according to the Generalized MANET Packet/Message Format defined in Request For Comments (RFC) 5444. Each node in the ad hoc network only advertises its own services. The advertisement frequency is a user-configurable parameter, so that it can be modified depending on the user requirements. Each node maintains two service tables, one to store information about its own services and another one to store information about the services it discovers in the network. We present simulation results, that compare our service discovery integrated into OLSRv2 with the one defined for OLSRv1 and with the integration of service discovery in Ad hoc On-demand Distance Vector (AODV) protocol, in terms of service discovery ratio, service latency and network overhead.

  11. An Optimal CDS Construction Algorithm with Activity Scheduling in Ad Hoc Networks.

    PubMed

    Penumalli, Chakradhar; Palanichamy, Yogesh

    2015-01-01

    A new energy efficient optimal Connected Dominating Set (CDS) algorithm with activity scheduling for mobile ad hoc networks (MANETs) is proposed. This algorithm achieves energy efficiency by minimizing the Broadcast Storm Problem [BSP] and at the same time considering the node's remaining energy. The Connected Dominating Set is widely used as a virtual backbone or spine in mobile ad hoc networks [MANETs] or Wireless Sensor Networks [WSN]. The CDS of a graph representing a network has a significant impact on an efficient design of routing protocol in wireless networks. Here the CDS is a distributed algorithm with activity scheduling based on unit disk graph [UDG]. The node's mobility and residual energy (RE) are considered as parameters in the construction of stable optimal energy efficient CDS. The performance is evaluated at various node densities, various transmission ranges, and mobility rates. The theoretical analysis and simulation results of this algorithm are also presented which yield better results.

  12. Stop_times based Routing Protocol for VANET

    NASA Astrophysics Data System (ADS)

    Moawad, Hafez; Shaaban, Eman; Taha Fayed, Zaki

    2013-11-01

    Vehicular Ad hoc Network (VANET) is a special class of Mobile Ad hoc Network (MANET) where vehicles are considered as MANET nodes with wireless links. The key difference of VANET and MANET is the special mobility pattern and rapidly changeable topology. There has been significant interest in improving safety and traffic efficiency using VANET. The design of routing protocols in VANET is important and necessary issue for support the smart ITS. Existing routing protocols of MANET are not suitable for VANET. AOMDV is the most important on demand multipath routing protocol. This paper proposes SSD-AOMDV as VANET routing protocol. SSD-AOMDV improves AOMDV to suit VANET characteristics. SSD-AOMDV adds the mobility parameters: Stop_times, Speed and Direction to hop count as new AOMDV routing metric to select next hop during the route discovery phase. Stop_times metric is added to simulate buses mobility pattern and traffic lights at intersections. Simulation results show that SSD-AOMDV achieves better performance compared to AOMDV.

  13. A Geographical Heuristic Routing Protocol for VANETs

    PubMed Central

    Urquiza-Aguiar, Luis; Tripp-Barba, Carolina; Aguilar Igartua, Mónica

    2016-01-01

    Vehicular ad hoc networks (VANETs) leverage the communication system of Intelligent Transportation Systems (ITS). Recently, Delay-Tolerant Network (DTN) routing protocols have increased their popularity among the research community for being used in non-safety VANET applications and services like traffic reporting. Vehicular DTN protocols use geographical and local information to make forwarding decisions. However, current proposals only consider the selection of the best candidate based on a local-search. In this paper, we propose a generic Geographical Heuristic Routing (GHR) protocol that can be applied to any DTN geographical routing protocol that makes forwarding decisions hop by hop. GHR includes in its operation adaptations simulated annealing and Tabu-search meta-heuristics, which have largely been used to improve local-search results in discrete optimization. We include a complete performance evaluation of GHR in a multi-hop VANET simulation scenario for a reporting service. Our study analyzes all of the meaningful configurations of GHR and offers a statistical analysis of our findings by means of MANOVA tests. Our results indicate that the use of a Tabu list contributes to improving the packet delivery ratio by around 5% to 10%. Moreover, if Tabu is used, then the simulated annealing routing strategy gets a better performance than the selection of the best node used with carry and forwarding (default operation). PMID:27669254

  14. A Geographical Heuristic Routing Protocol for VANETs.

    PubMed

    Urquiza-Aguiar, Luis; Tripp-Barba, Carolina; Aguilar Igartua, Mónica

    2016-09-23

    Vehicular ad hoc networks (VANETs) leverage the communication system of Intelligent Transportation Systems (ITS). Recently, Delay-Tolerant Network (DTN) routing protocols have increased their popularity among the research community for being used in non-safety VANET applications and services like traffic reporting. Vehicular DTN protocols use geographical and local information to make forwarding decisions. However, current proposals only consider the selection of the best candidate based on a local-search. In this paper, we propose a generic Geographical Heuristic Routing (GHR) protocol that can be applied to any DTN geographical routing protocol that makes forwarding decisions hop by hop. GHR includes in its operation adaptations simulated annealing and Tabu-search meta-heuristics, which have largely been used to improve local-search results in discrete optimization. We include a complete performance evaluation of GHR in a multi-hop VANET simulation scenario for a reporting service. Our study analyzes all of the meaningful configurations of GHR and offers a statistical analysis of our findings by means of MANOVA tests. Our results indicate that the use of a Tabu list contributes to improving the packet delivery ratio by around 5% to 10%. Moreover, if Tabu is used, then the simulated annealing routing strategy gets a better performance than the selection of the best node used with carry and forwarding (default operation).

  15. Security Verification of Secure MANET Routing Protocols

    DTIC Science & Technology

    2012-03-22

    Approved: L1 FEB 12.. Maj Todd R . Andel, PhD (Chairman) Date ~~ Rb 12 Date Date Abstract Secure mobile ad hoc network (MANET) routing protocols are...topology, T=5. 17 Listing 2.1: MPR Selection Algorithm [16]. 1 s e t N2 [ n ] , n e i g h b o r ; 2 3 s e t MPR Selec t ion ( s e t ans , i n t s r c...4 s e l e c t e e = ∅ ; / ∗ ( i ) Remove a l l e n t r i e s from s e l e c t e e ∗ / 5 ans = ans \\ i d ; / ∗ ( i i ) Exc lude y o u r s e l f from

  16. A native Bayesian classifier based routing protocol for VANETS

    NASA Astrophysics Data System (ADS)

    Bao, Zhenshan; Zhou, Keqin; Zhang, Wenbo; Gong, Xiaolei

    2016-12-01

    Geographic routing protocols are one of the most hot research areas in VANET (Vehicular Ad-hoc Network). However, there are few routing protocols can take both the transmission efficient and the usage of ratio into account. As we have noticed, different messages in VANET may ask different quality of service. So we raised a Native Bayesian Classifier based routing protocol (Naive Bayesian Classifier-Greedy, NBC-Greedy), which can classify and transmit different messages by its emergency degree. As a result, we can balance the transmission efficient and the usage of ratio with this protocol. Based on Matlab simulation, we can draw a conclusion that NBC-Greedy is more efficient and stable than LR-Greedy and GPSR.

  17. Building a Simulation Toolkit for Wireless Mesh Clusters and Evaluating the Suitability of Different Families of Ad Hoc Protocols for the Tactical Network Topology

    DTIC Science & Technology

    2005-03-01

    we are going to highlight some of the most important studies and analyze their conclusions. Broch et al (1998) used the ns-2 simulator to compare...delay and routing load. The authors concluded that their results are very similar with the work of Broch et al (1998). Johansson et al (1999) focused...Hoc Networking, ed. S. Basagni, M. Conti, S. Giordano and I. Stojmenovic, 373-409, John Wiley & Sons, Inc. Broch , J., D.A. Maltz, D.B. Johnson, Y.-C

  18. Voice Traffic over Mobile Ad Hoc Networks: A Performance Analysis of the Optimized Link State Routing Protocol

    DTIC Science & Technology

    2009-03-26

    58 C.1. Outlier Identification - Delay . . . . . . . . . . . . . . . . . . . 85 C.2. Outlier Identification - Packet Loss...outlier identification criterion. These values are considered outliers since they do not appear to belong with the rest of the values in the data set...Table C.1: Outlier Identification - Delay 10 25 0 30 1 0 50 10 0 50 25 1 Data entry mistake NO NO NO NO Obtained from NO NO NO NO different population

  19. Management of Energy Consumption on Cluster Based Routing Protocol for MANET

    NASA Astrophysics Data System (ADS)

    Hosseini-Seno, Seyed-Amin; Wan, Tat-Chee; Budiarto, Rahmat; Yamada, Masashi

    The usage of light-weight mobile devices is increasing rapidly, leading to demand for more telecommunication services. Consequently, mobile ad hoc networks and their applications have become feasible with the proliferation of light-weight mobile devices. Many protocols have been developed to handle service discovery and routing in ad hoc networks. However, the majority of them did not consider one critical aspect of this type of network, which is the limited of available energy in each node. Cluster Based Routing Protocol (CBRP) is a robust/scalable routing protocol for Mobile Ad hoc Networks (MANETs) and superior to existing protocols such as Ad hoc On-demand Distance Vector (AODV) in terms of throughput and overhead. Therefore, based on this strength, methods to increase the efficiency of energy usage are incorporated into CBRP in this work. In order to increase the stability (in term of life-time) of the network and to decrease the energy consumption of inter-cluster gateway nodes, an Enhanced Gateway Cluster Based Routing Protocol (EGCBRP) is proposed. Three methods have been introduced by EGCBRP as enhancements to the CBRP: improving the election of cluster Heads (CHs) in CBRP which is based on the maximum available energy level, implementing load balancing for inter-cluster traffic using multiple gateways, and implementing sleep state for gateway nodes to further save the energy. Furthermore, we propose an Energy Efficient Cluster Based Routing Protocol (EECBRP) which extends the EGCBRP sleep state concept into all idle member nodes, excluding the active nodes in all clusters. The experiment results show that the EGCBRP decreases the overall energy consumption of the gateway nodes up to 10% and the EECBRP reduces the energy consumption of the member nodes up to 60%, both of which in turn contribute to stabilizing the network.

  20. Performance optimisation through EPT-WBC in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Agarwal, Ratish; Gupta, Roopam; Motwani, Mahesh

    2016-03-01

    Mobile ad hoc networks are self-organised, infrastructure-less networks in which each mobile host works as a router to provide connectivity within the network. Nodes out of reach to each other can communicate with the help of intermediate routers (nodes). Routing protocols are the rules which determine the way in which these routing activities are to be performed. In cluster-based architecture, some selected nodes (clusterheads) are identified to bear the extra burden of network activities like routing. Selection of clusterheads is a critical issue which significantly affects the performance of the network. This paper proposes an enhanced performance and trusted weight-based clustering approach in which a number of performance factors such as trust, load balancing, energy consumption, mobility and battery power are considered for the selection of clusterheads. Moreover, the performance of the proposed scheme is compared with other existing approaches to demonstrate the effectiveness of the work.

  1. Distribution of Information in Ad Hoc Networks

    DTIC Science & Technology

    2007-09-01

    INTENTIONALLY LEFT BLANK v ABSTRACT Ad-hoc networks are distributed, self-organized networks which do not need a fixed infrastructure. Entities in...73 V . CONCLUSIONS AND FUTURE WORK ............................75 A. OVERVIEW ..........................................75 B. CONCLUSIONS...statistical analysis on the results. Finally, Chapter V concludes the research and provides suggestions for further research. 7 II. BACKGROUND A

  2. Anomaly Detection Techniques for Ad Hoc Networks

    ERIC Educational Resources Information Center

    Cai, Chaoli

    2009-01-01

    Anomaly detection is an important and indispensable aspect of any computer security mechanism. Ad hoc and mobile networks consist of a number of peer mobile nodes that are capable of communicating with each other absent a fixed infrastructure. Arbitrary node movements and lack of centralized control make them vulnerable to a wide variety of…

  3. Energy Efficient Probabilistic Broadcasting for Mobile Ad-Hoc Network

    NASA Astrophysics Data System (ADS)

    Kumar, Sumit; Mehfuz, Shabana

    2016-08-01

    In mobile ad-hoc network (MANETs) flooding method is used for broadcasting route request (RREQ) packet from one node to another node for route discovery. This is the simplest method of broadcasting of RREQ packets but it often results in broadcast storm problem, originating collisions and congestion of packets in the network. A probabilistic broadcasting is one of the widely used broadcasting scheme for route discovery in MANETs and provides solution for broadcasting storm problem. But it does not consider limited energy of the battery of the nodes. In this paper, a new energy efficient probabilistic broadcasting (EEPB) is proposed in which probability of broadcasting RREQs is calculated with respect to remaining energy of nodes. The analysis of simulation results clearly indicate that an EEPB route discovery scheme in ad-hoc on demand distance vector (AODV) can increase the network lifetime with a decrease in the average power consumption and RREQ packet overhead. It also decreases the number of dropped packets in the network, in comparison to other EEPB schemes like energy constraint gossip (ECG), energy aware gossip (EAG), energy based gossip (EBG) and network lifetime through energy efficient broadcast gossip (NEBG).

  4. Supporting Dynamic Ad hoc Collaboration Capabilities

    SciTech Connect

    Agarwal, Deborah A.; Berket, Karlo

    2003-07-14

    Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on building a dynamic and ad hoc collaboration environment and our vision for its evolution into a HENP collaboration environment.

  5. Ad Hoc Selection of Voice over Internet Streams

    NASA Technical Reports Server (NTRS)

    Macha, Mitchell G. (Inventor); Bullock, John T. (Inventor)

    2008-01-01

    A method and apparatus for a communication system technique involving ad hoc selection of at least two audio streams is provided. Each of the at least two audio streams is a packetized version of an audio source. A data connection exists between a server and a client where a transport protocol actively propagates the at least two audio streams from the server to the client. Furthermore, software instructions executable on the client indicate a presence of the at least two audio streams, allow selection of at least one of the at least two audio streams, and direct the selected at least one of the at least two audio streams for audio playback.

  6. Ad Hoc Selection of Voice over Internet Streams

    NASA Technical Reports Server (NTRS)

    Macha, Mitchell G. (Inventor); Bullock, John T. (Inventor)

    2014-01-01

    A method and apparatus for a communication system technique involving ad hoc selection of at least two audio streams is provided. Each of the at least two audio streams is a packetized version of an audio source. A data connection exists between a server and a client where a transport protocol actively propagates the at least two audio streams from the server to the client. Furthermore, software instructions executable on the client indicate a presence of the at least two audio streams, allow selection of at least one of the at least two audio streams, and direct the selected at least one of the at least two audio streams for audio playback.

  7. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2008-08-01

    Maximization in Multi-User, MIMO Channels with Linear Processing...58 2.9 Using Feedback in Ad Hoc Networks....................................................................65 2.10 Feedback MIMO ...in MIMO Ad Hoc Interference Networks.......................................................................................................75 2.12

  8. AD Hoc Study on Human Robot Interface Issues

    DTIC Science & Technology

    2002-09-01

    ARMY SCIENCE BOARD AD HOC STUDY ON HUMAN ROBOT INTERFACE ISSUES FINAL REPORT SEPTEMBER 2002 Distribution: Approved for...conclusions contained in this report are those of the 2002 Ad Hoc Study Panel on “Human- Robot Interface Issues” and do not necessarily reflect the official...DATES COVERED Army Science Board – 2002 Ad Hoc Study 4. TITLE AND SUBTITLE AD HOC STUDY ON HUMAN ROBOT INTERFACE ISSUES 6. AUTHOR(S) Study

  9. Effective Mobile Routing Through Dynamic Addressing

    DTIC Science & Technology

    2007-03-01

    WIRELESS BATTLEFIELD NETWORKS USING UAVS,” 2001. [7] Elizabeth . M. Royer, Chai-Keong Toh, “A Review of Current Routing Protocols for Ad-Hoc Mobile...Wireless Networks,” IEEE personal Communications, April 1999. [8] S. Corson , J. Macker, “Mobile Ad-hoc Networking (MANET) : Routing Protocol...Charles E. Perkins, Elizabeth M. Royer, “Ad-hoc On-Demand Distance Vector Routing,”wmcsa, p.90, Second IEEE Workshop on Mobile Computer System and

  10. GEM: Graph EMbedding for Routing and Data-Centric Storage in Sensor Networks without Geographic Information

    DTIC Science & Technology

    2003-03-01

    Broch et. al. provide a survey of several ad hoc routing protocols[6], including DSDV[26], TORA[22], DSR[16][17], and AODV[27]. Data Dissemination... Broch , David A. Maltz, David B. Johnson, Yih-Chun Hu, and Jorjeta Jetcheva. A performance comparison of multi-hop wireless ad hoc network routing

  11. VANET Clustering Based Routing Protocol Suitable for Deserts

    PubMed Central

    Mohammed Nasr, Mohammed Mohsen; Abdelgader, Abdeldime Mohamed Salih; Wang, Zhi-Gong; Shen, Lian-Feng

    2016-01-01

    In recent years, there has emerged applications of vehicular ad hoc networks (VANETs) towards security, safety, rescue, exploration, military and communication redundancy systems in non-populated areas, besides its ordinary use in urban environments as an essential part of intelligent transportation systems (ITS). This paper proposes a novel algorithm for the process of organizing a cluster structure and cluster head election (CHE) suitable for VANETs. Moreover, it presents a robust clustering-based routing protocol, which is appropriate for deserts and can achieve high communication efficiency, ensuring reliable information delivery and optimal exploitation of the equipment on each vehicle. A comprehensive simulation is conducted to evaluate the performance of the proposed CHE and routing algorithms. PMID:27058539

  12. VANET Clustering Based Routing Protocol Suitable for Deserts.

    PubMed

    Nasr, Mohammed Mohsen Mohammed; Abdelgader, Abdeldime Mohamed Salih; Wang, Zhi-Gong; Shen, Lian-Feng

    2016-04-06

    In recent years, there has emerged applications of vehicular ad hoc networks (VANETs) towards security, safety, rescue, exploration, military and communication redundancy systems in non-populated areas, besides its ordinary use in urban environments as an essential part of intelligent transportation systems (ITS). This paper proposes a novel algorithm for the process of organizing a cluster structure and cluster head election (CHE) suitable for VANETs. Moreover, it presents a robust clustering-based routing protocol, which is appropriate for deserts and can achieve high communication efficiency, ensuring reliable information delivery and optimal exploitation of the equipment on each vehicle. A comprehensive simulation is conducted to evaluate the performance of the proposed CHE and routing algorithms.

  13. 14 CFR 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Ad hoc committees. 1203.903 Section 1203... NASA Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is authorized to establish such ad hoc panels or subcommittees as may be necessary in the conduct of the...

  14. 14 CFR 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Ad hoc committees. 1203.903 Section 1203.903... Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is authorized to establish such ad hoc panels or subcommittees as may be necessary in the conduct of the Committee's work....

  15. 21 CFR 14.90 - Ad hoc advisory committee members.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ad hoc advisory committee members. 14.90 Section... PUBLIC HEARING BEFORE A PUBLIC ADVISORY COMMITTEE Members of Advisory Committees § 14.90 Ad hoc advisory committee members. In selecting members of an ad hoc advisory committee, the Commissioner may use...

  16. 21 CFR 14.90 - Ad hoc advisory committee members.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ad hoc advisory committee members. 14.90 Section... PUBLIC HEARING BEFORE A PUBLIC ADVISORY COMMITTEE Members of Advisory Committees § 14.90 Ad hoc advisory committee members. In selecting members of an ad hoc advisory committee, the Commissioner may use...

  17. Adaptive link-layer intelligence for enhanced ad hoc networking

    NASA Astrophysics Data System (ADS)

    MacLennan, James; Walburg, Bill; Nevins, Larry; Hartup, David

    2005-05-01

    Networked radio systems that utilize self-forming, fault tolerant techniques offer needed communication functions for Homeland Security and Law Enforcement agencies. The use of an ad hoc mesh network architecture solves some of the problems inherent to the wireless physical layer such as interferers, multi-path fading, shadowing, and loss of line-of-site. These effects severely limit the performance of current 802.11 wireless network implementations. This paper describes the use of Adaptive Link-layer Intelligence for Enhanced ad hoc Networking. This technology enhances recognition and characterization of sources of wireless channel perturbations and predicts their effects on wireless link quality. Identifying and predicting channel problems at the link level improves dynamic route discovery, circumvents channel disruptions before they cause a link failure, and increases communications reliability and data rate. First Responders, Homeland Security, and Law Enforcement agencies operating in locations lacking infrastructure, such as Urban Search and Rescue (USAR) operations, can benefit from increased communications reliability in highly impaired channels that are typical in disaster response scenarios.

  18. Design of Intelligent Cross-Layer Routing Protocols for Airborne Wireless Networks Under Dynamic Spectrum Access Paradigm

    DTIC Science & Technology

    2011-05-01

    manet-aodv-11.txt 107 17. D. Johnson, D. A. Maltz, and J. Broch , “The Dynamic Source Routing Protocol for Mobile Ad Hoc Networks,” IETF Internet...multipath distance vector routing,” Wireless Communications And Mobile Computing, vol. 6, pp. 969–988, 2006. 51. J. Broch , D. Maltz, D. Johnson, Y. Hu...wireless networks,” Proc. INFOCOM’97, pp. 1405–1413, April 1997. 55. J. Broch , D. Johnson, and D.Maltz, “The dynamic source routing protocol for mobile ad

  19. On the Routing Protocol Influence on the Resilience of Wireless Sensor Networks to Jamming Attacks

    PubMed Central

    Del-Valle-Soto, Carolina; Mex-Perera, Carlos; Monroy, Raul; Nolazco-Flores, Juan Arturo

    2015-01-01

    In this work, we compare a recently proposed routing protocol, the multi-parent hierarchical (MPH) protocol, with two well-known protocols, the ad hoc on-demand distance vector (AODV) and dynamic source routing (DSR). For this purpose, we have developed a simulator, which faithfully reifies the workings of a given protocol, considering a fixed, reconfigurable ad hoc network given by the number and location of participants, and general network conditions. We consider a scenario that can be found in a large number of wireless sensor network applications, a single sink node that collects all of the information generated by the sensors. The metrics used to compare the protocols were the number of packet retransmissions, carrier sense multiple access (CSMA) inner loop retries, the number of nodes answering the queries from the coordinator (sink) node and the energy consumption. We tested the network under ordinary (without attacks) conditions (and combinations thereof) and when it is subject to different types of jamming attacks (in particular, random and reactive jamming attacks), considering several positions for the jammer. Our results report that MPH has a greater ability to tolerate such attacks than DSR and AODV, since it minimizes and encapsulates the network segment under attack. The self-configuring capabilities of MPH derived from a combination of a proactive routes update, on a periodic-time basis, and a reactive behavior provide higher resilience while offering a better performance (overhead and energy consumption) than AODV and DSR, as shown in our simulation results. PMID:25825979

  20. Cooperative Multi-Agent Systems in Mobile Ad Hoc Networks

    DTIC Science & Technology

    2006-01-01

    COOPERATIVE MULTI - AGENT SYSTEMS IN MOBILE AD HOC NETWORKS Joseph P. Macker William Chao Myriam Abramson Ian Downard Information Technology Division...are, mobile ad hoc networking (MANET) and Multi - Agent Systems (MAS). Despite their value in enabling more autonomous network system operation...2006 to 00-00-2006 4. TITLE AND SUBTITLE Cooperative Multi - Agent Systems in Mobile Ad Hoc Networks 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  1. Spontaneous Ad Hoc Mobile Cloud Computing Network

    PubMed Central

    Lacuesta, Raquel; Sendra, Sandra; Peñalver, Lourdes

    2014-01-01

    Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes. PMID:25202715

  2. Spontaneous ad hoc mobile cloud computing network.

    PubMed

    Lacuesta, Raquel; Lloret, Jaime; Sendra, Sandra; Peñalver, Lourdes

    2014-01-01

    Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes.

  3. SVANET: A smart vehicular ad hoc network for efficient data transmission with wireless sensors.

    PubMed

    Sahoo, Prasan Kumar; Chiang, Ming-Jer; Wu, Shih-Lin

    2014-11-25

    Wireless sensors can sense any event, such as accidents, as well as icy roads, and can forward the rescue/warning messages through intermediate vehicles for any necessary help. In this paper, we propose a smart vehicular ad hoc network (SVANET) architecture that uses wireless sensors to detect events and vehicles to transmit the safety and non-safety messages efficiently by using different service channels and one control channel with different priorities. We have developed a data transmission protocol for the vehicles in the highway, in which data can be forwarded with the help of vehicles if they are connected with each other or data can be forwarded with the help of nearby wireless sensors. Our data transmission protocol is designed to increase the driving safety, to prevent accidents and to utilize channels efficiently by adjusting the control and service channel time intervals dynamically. Besides, our protocol can transmit information to vehicles in advance, so that drivers can decide an alternate route in case of traffic congestion. For various data sharing, we design a method that can select a few leader nodes among vehicles running along a highway to broadcast data efficiently. Simulation results show that our protocol can outperform the existing standard in terms of the end to end packet delivery ratio and latency.

  4. SVANET: A Smart Vehicular Ad Hoc Network for Efficient Data Transmission with Wireless Sensors

    PubMed Central

    Sahoo, Prasan Kumar; Chiang, Ming-Jer; Wu, Shih-Lin

    2014-01-01

    Wireless sensors can sense any event, such as accidents, as well as icy roads, and can forward the rescue/warning messages through intermediate vehicles for any necessary help. In this paper, we propose a smart vehicular ad hoc network (SVANET) architecture that uses wireless sensors to detect events and vehicles to transmit the safety and non-safety messages efficiently by using different service channels and one control channel with different priorities. We have developed a data transmission protocol for the vehicles in the highway, in which data can be forwarded with the help of vehicles if they are connected with each other or data can be forwarded with the help of nearby wireless sensors. Our data transmission protocol is designed to increase the driving safety, to prevent accidents and to utilize channels efficiently by adjusting the control and service channel time intervals dynamically. Besides, our protocol can transmit information to vehicles in advance, so that drivers can decide an alternate route in case of traffic congestion. For various data sharing, we design a method that can select a few leader nodes among vehicles running along a highway to broadcast data efficiently. Simulation results show that our protocol can outperform the existing standard in terms of the end to end packet delivery ratio and latency. PMID:25429409

  5. A Multimetric, Map-Aware Routing Protocol for VANETs in Urban Areas

    PubMed Central

    Tripp-Barba, Carolina; Urquiza-Aguiar, Luis; Igartua, Mónica Aguilar; Rebollo-Monedero, David; de la Cruz Llopis, Luis J.; Mezher, Ahmad Mohamad; Aguilar-Calderón, José Alfonso

    2014-01-01

    In recent years, the general interest in routing for vehicular ad hoc networks (VANETs) has increased notably. Many proposals have been presented to improve the behavior of the routing decisions in these very changeable networks. In this paper, we propose a new routing protocol for VANETs that uses four different metrics. which are the distance to destination, the vehicles' density, the vehicles' trajectory and the available bandwidth, making use of the information retrieved by the sensors of the vehicle, in order to make forwarding decisions, minimizing packet losses and packet delay. Through simulation, we compare our proposal to other protocols, such as AODV (Ad hoc On-Demand Distance Vector), GPSR (Greedy Perimeter Stateless Routing), I-GPSR (Improvement GPSR) and to our previous proposal, GBSR-B (Greedy Buffer Stateless Routing Building-aware). Besides, we present a performance evaluation of the individual importance of each metric to make forwarding decisions. Experimental results show that our proposed forwarding decision outperforms existing solutions in terms of packet delivery. PMID:24476683

  6. A multimetric, map-aware routing protocol for VANETs in urban areas.

    PubMed

    Tripp-Barba, Carolina; Urquiza-Aguiar, Luis; Aguilar Igartua, Mónica; Rebollo-Monedero, David; de la Cruz Llopis, Luis J; Mezher, Ahmad Mohamad; Aguilar-Calderón, José Alfonso

    2014-01-28

    In recent years, the general interest in routing for vehicular ad hoc networks (VANETs) has increased notably. Many proposals have been presented to improve the behavior of the routing decisions in these very changeable networks. In this paper, we propose a new routing protocol for VANETs that uses four different metrics. which are the distance to destination, the vehicles' density, the vehicles' trajectory and the available bandwidth, making use of the information retrieved by the sensors of the vehicle, in order to make forwarding decisions, minimizing packet losses and packet delay. Through simulation, we compare our proposal to other protocols, such as AODV (Ad hoc On-Demand Distance Vector), GPSR (Greedy Perimeter Stateless Routing), I-GPSR (Improvement GPSR) and to our previous proposal, GBSR-B (Greedy Buffer Stateless Routing Building-aware). Besides, we present a performance evaluation of the individual importance of each metric to make forwarding decisions. Experimental results show that our proposed forwarding decision outperforms existing solutions in terms of packet delivery.

  7. Assured Resource Sharing in Ad-Hoc Collaboration

    SciTech Connect

    Ahn, Gail-Joon

    2015-12-19

    The project seeks an innovative framework to enable users to access and selectively share resources in distributed environments, enhancing the scalability of information sharing. We have investigated secure sharing & assurance approaches for ad-hoc collaboration, focused on Grids, Clouds, and ad-hoc network environments.

  8. 14 CFR 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Ad hoc committees. 1203.903 Section 1203.903 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM NASA Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is...

  9. 14 CFR § 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Ad hoc committees. § 1203.903 Section § 1203.903 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM NASA Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson...

  10. 14 CFR 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Ad hoc committees. 1203.903 Section 1203.903 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM NASA Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is...

  11. Assured Information Sharing for Ad-Hoc Collaboration

    ERIC Educational Resources Information Center

    Jin, Jing

    2009-01-01

    Collaborative information sharing tends to be highly dynamic and often ad hoc among organizations. The dynamic natures and sharing patterns in ad-hoc collaboration impose a need for a comprehensive and flexible approach to reflecting and coping with the unique access control requirements associated with the environment. This dissertation…

  12. Ad Hoc Networking for Unmanned Ground Vehicles: Design and Evaluation at Command, Control, Communications, Intelligence, Surveillance and Reconnaissance On-the-Move

    DTIC Science & Technology

    2006-11-01

    software components used in the ad hoc nodes for the C4ISR OTM experiment were OLSRD, an open-source proactive MANET routing software, and OpenVPN , an...developed by Mike Baker (openwrt.org). 6OpenVPN is a trademark of OpenVPN Solutions LLC. 6 Secure communications in the MANET are achieved with...encryption provided by Wired Equivalent Privacy (WEP) and OpenVPN . The WEP protocol, which is part of the IEEE 802.11 wireless networking standard

  13. A Novel Approach to Overlay Multicasting Schemes for Multi-Hop Ad-Hoc Networks

    NASA Astrophysics Data System (ADS)

    Kang, Namhi; Oh, Jejun; Kim, Younghan

    Multicast is an efficient transport mechanism for group-based community communications and mobile ad-hoc networks (MANET) is recently regarded as a promising solution for supporting ubiquitous computing as an underlying network technology. However, it is challenging to deploy the multicast mechanism used in a wired network directly into MANET owing to scarce resources in wireless networks and unpredictable changes in network topology. Several multicast mechanisms have been proposed in the literature to overcome these limitations. In MANET, especially, overlay multicasting schemes present several advantages over network-based multicasting schemes. However we have observed a common limitation of previously proposed overlay multicasting schemes. They introduce redundant data transmissions that waste network bandwidth and the battery of relay nodes. The observation motivated us to propose an efficient way to create and maintain a “semi-overlay structure” that utilizes a few nonmember nodes selected as branch nodes. The proposed scheme, called “SOMRP (Semi-overlay multicast routing protocol),” has been evaluated by using extensive network simulation in two different scenarios, comparing the performance of SOMRP with two previously proposed schemes. Simulation results show that SOMRP outperforms the two schemes in terms of the packet delivery ratio, transmission cost and end-to-end delay.

  14. An Ad-hoc Satellite Network to Measure Filamentary Current Structures in the Auroral Zone

    NASA Astrophysics Data System (ADS)

    Nabong, C.; Fritz, T. A.; Semeter, J. L.

    2014-12-01

    An ad-hoc cubesat-based satellite network project known as ANDESITE is under development at Boston University. It aims to develop a dense constellation of easy-to-use, rapidly-deployable low-cost wireless sensor nodes in space. The objectives of the project are threefold: 1) Demonstrate viability of satellite based sensor networks by deploying an 8-node miniature sensor network to study the filamentation of the field aligned currents in the auroral zones of the Earth's magnetosphere. 2) Test the scalability of proposed protocols, including localization techniques, tracking, data aggregation, and routing, for a 3 dimensional wireless sensor network using a "flock" of nodes. 3) Construct a 6U Cube-sat running the Android OS as an integrated constellation manager, data mule and sensor node deplorer. This small network of sensor nodes will resolve current densities at different spatial resolutions in the near-Earth magnetosphere using measurements from magnetometers with 1-nT sensitivities and 0.2 nT/√Hz self-noise. Mapping of these currents will provide new constraints for models of auroral particle acceleration, wave-particle interactions, ionospheric destabilization, and other kinetic processes operating in the low-beta plasma of the near Earth magnetosphere.

  15. The Ad Hoc process to strengthen the framework convention on climate change

    SciTech Connect

    Ramakrishna, K.; Deutz, A.M.; Jacobsen, L.A.

    1995-11-01

    The Woods Hole Research Center convened an International Conference on The Ad Hoc Process to Strengthen the Framework Convention on Climate Change in Woods Hole, MA, on October 7-9, 1995. The conference was conducted to examine the prospects for successful adoption of a protocol to the Framework Convention on Climate Change by 1997. In preparation for the Second session of the Ad Hoc Group on the Berlin Mandate, several governmental and nongovernmental representatives met in Woods Hole to discuss the process and possible outcome of the Berlin Mandate negotiations for a protocol or other legal instrument to strengthen the Convention. The conference was by invitation and all participants attended in their personal capacities.

  16. Virtual machine-based simulation platform for mobile ad-hoc network-based cyber infrastructure

    SciTech Connect

    Yoginath, Srikanth B.; Perumalla, Kayla S.; Henz, Brian J.

    2015-09-29

    In modeling and simulating complex systems such as mobile ad-hoc networks (MANETs) in de-fense communications, it is a major challenge to reconcile multiple important considerations: the rapidity of unavoidable changes to the software (network layers and applications), the difficulty of modeling the critical, implementation-dependent behavioral effects, the need to sustain larger scale scenarios, and the desire for faster simulations. Here we present our approach in success-fully reconciling them using a virtual time-synchronized virtual machine(VM)-based parallel ex-ecution framework that accurately lifts both the devices as well as the network communications to a virtual time plane while retaining full fidelity. At the core of our framework is a scheduling engine that operates at the level of a hypervisor scheduler, offering a unique ability to execute multi-core guest nodes over multi-core host nodes in an accurate, virtual time-synchronized manner. In contrast to other related approaches that suffer from either speed or accuracy issues, our framework provides MANET node-wise scalability, high fidelity of software behaviors, and time-ordering accuracy. The design and development of this framework is presented, and an ac-tual implementation based on the widely used Xen hypervisor system is described. Benchmarks with synthetic and actual applications are used to identify the benefits of our approach. The time inaccuracy of traditional emulation methods is demonstrated, in comparison with the accurate execution of our framework verified by theoretically correct results expected from analytical models of the same scenarios. In the largest high fidelity tests, we are able to perform virtual time-synchronized simulation of 64-node VM-based full-stack, actual software behaviors of MANETs containing a mix of static and mobile (unmanned airborne vehicle) nodes, hosted on a 32-core host, with full fidelity of unmodified ad-hoc routing protocols, unmodified application

  17. Virtual machine-based simulation platform for mobile ad-hoc network-based cyber infrastructure

    DOE PAGES

    Yoginath, Srikanth B.; Perumalla, Kayla S.; Henz, Brian J.

    2015-09-29

    In modeling and simulating complex systems such as mobile ad-hoc networks (MANETs) in de-fense communications, it is a major challenge to reconcile multiple important considerations: the rapidity of unavoidable changes to the software (network layers and applications), the difficulty of modeling the critical, implementation-dependent behavioral effects, the need to sustain larger scale scenarios, and the desire for faster simulations. Here we present our approach in success-fully reconciling them using a virtual time-synchronized virtual machine(VM)-based parallel ex-ecution framework that accurately lifts both the devices as well as the network communications to a virtual time plane while retaining full fidelity. At themore » core of our framework is a scheduling engine that operates at the level of a hypervisor scheduler, offering a unique ability to execute multi-core guest nodes over multi-core host nodes in an accurate, virtual time-synchronized manner. In contrast to other related approaches that suffer from either speed or accuracy issues, our framework provides MANET node-wise scalability, high fidelity of software behaviors, and time-ordering accuracy. The design and development of this framework is presented, and an ac-tual implementation based on the widely used Xen hypervisor system is described. Benchmarks with synthetic and actual applications are used to identify the benefits of our approach. The time inaccuracy of traditional emulation methods is demonstrated, in comparison with the accurate execution of our framework verified by theoretically correct results expected from analytical models of the same scenarios. In the largest high fidelity tests, we are able to perform virtual time-synchronized simulation of 64-node VM-based full-stack, actual software behaviors of MANETs containing a mix of static and mobile (unmanned airborne vehicle) nodes, hosted on a 32-core host, with full fidelity of unmodified ad-hoc routing protocols, unmodified

  18. Instability Free Routing: Beyond One Protocol Instance

    DTIC Science & Technology

    2008-12-01

    assigned a Rout- ing Information Base (RIB) [13]. This database is used to store the routing information related to the routing process (e.g., routes...presents routing anomalies that can derive from route selection by itself, i.e., without any route redis - tribution configured between the routing... redis - tributed into the RIP protocol, all RIP messages received from the neighbors are in fact discarded independently of the AD values. This

  19. Greedy data transportation scheme with hard packet deadlines for wireless ad hoc networks.

    PubMed

    Lee, HyungJune

    2014-01-01

    We present a greedy data transportation scheme with hard packet deadlines in ad hoc sensor networks of stationary nodes and multiple mobile nodes with scheduled trajectory path and arrival time. In the proposed routing strategy, each stationary ad hoc node en route decides whether to relay a shortest-path stationary node toward destination or a passing-by mobile node that will carry closer to destination. We aim to utilize mobile nodes to minimize the total routing cost as far as the selected route can satisfy the end-to-end packet deadline. We evaluate our proposed routing algorithm in terms of routing cost, packet delivery ratio, packet delivery time, and usability of mobile nodes based on network level simulations. Simulation results show that our proposed algorithm fully exploits the remaining time till packet deadline to turn into networking benefits of reducing the overall routing cost and improving packet delivery performance. Also, we demonstrate that the routing scheme guarantees packet delivery with hard deadlines, contributing to QoS improvement in various network services.

  20. Design of free patterns of nanocrystals with ad hoc features via templated dewetting

    NASA Astrophysics Data System (ADS)

    Aouassa, M.; Berbezier, I.; Favre, L.; Ronda, A.; Bollani, M.; Sordan, R.; Delobbe, A.; Sudraud, P.

    2012-07-01

    Design of monodisperse ultra-small nanocrystals (NCs) into large scale patterns with ad hoc features is demonstrated. The process makes use of solid state dewetting of a thin film templated through alloy liquid metal ion source focused ion beam (LMIS-FIB) nanopatterning. The solid state dewetting initiated at the edges of the patterns controllably creates the ordering of NCs with ad hoc placement and periodicity. The NC size is tuned by varying the nominal thickness of the film while their position results from the association of film retraction from the edges of the lay out and Rayleigh-like instability. The use of ultra-high resolution LMIS-FIB enables to produce monocrystalline NCs with size, periodicity, and placement tunable as well. It provides routes for the free design of nanostructures for generic applications in nanoelectronics.

  1. Global Coverage from Ad-Hoc Constellations in Rideshare Orbits

    NASA Technical Reports Server (NTRS)

    Ellis, Armin; Mercury, Michael; Brown, Shannon

    2012-01-01

    A promising area of small satellite development is in providing higher temporal resolution than larger satellites. Traditional constellations have required specific orbits and dedicated launch vehicles. In this paper we discuss an alternative architecture in which the individual elements of the constellation are launched as rideshare opportunities. We compare the coverage of such an ad-hoc constellation with more traditional constellations. Coverage analysis is based on actual historical data from rideshare opportunities. Our analysis includes ground coverage and temporal revisits for Polar, Tropics, Temperate, and Global regions, comparing ad-hoc and Walker constellation.

  2. How to Bootstrap Security for Ad-Hoc Network: Revisited

    NASA Astrophysics Data System (ADS)

    Shin, Wook; Gunter, Carl A.; Kiyomoto, Shinsaku; Fukushima, Kazuhide; Tanaka, Toshiaki

    There are various network-enabled and embedded computers deployed around us. Although we can get enormous conveniences by connecting them together, it is difficult to securely associate them in an ad-hoc manner. The difficulties originate from authentication and key distribution problems among devices that are strangers to each other. In this paper, we review the existing ways of initiating secure communication for ad-hoc network devices, and propose another solution. Exploiting Pairing-based cryptography and the notion of location-limited channel, the proposed solution bootstraps security conveniently and efficiently. Further, it supports ownership enforcement and key-escrow.

  3. Ad Hoc Technical Committee for Vocational Agriculture. Final Report.

    ERIC Educational Resources Information Center

    Indiana State Commission on Vocational and Technical Education, Indianapolis.

    The goal of the Ad Hoc Technical Committee for Vocational Agriculture in Indiana was to develop a model and recommendations that would result in improved student knowledge and skills for the present and future, address labor market needs, and promote program excellence at all levels of education. The committee developed recommendations for…

  4. 14 CFR § 1203.1002 - Ad hoc committees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Ad hoc committees. § 1203.1002 Section § 1203.1002 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM Special Access Programs (SAP) and Sensitive Compartmented Information (SCI) Programs...

  5. Providing Location Security in Vehicular Ad Hoc Networks

    ERIC Educational Resources Information Center

    Yan, Gongjun

    2010-01-01

    Location is fundamental information in Vehicular Ad-hoc Networks (VANETs). Almost all VANET applications rely on location information. Therefore it is of importance to ensure location information integrity, meaning that location information is original (from the generator), correct (not bogus or fabricated) and unmodified (value not changed). We…

  6. Cost-Effective Encryption-Based Autonomous Routing Protocol for Efficient and Secure Wireless Sensor Networks

    PubMed Central

    Saleem, Kashif; Derhab, Abdelouahid; Orgun, Mehmet A.; Al-Muhtadi, Jalal; Rodrigues, Joel J. P. C.; Khalil, Mohammed Sayim; Ali Ahmed, Adel

    2016-01-01

    The deployment of intelligent remote surveillance systems depends on wireless sensor networks (WSNs) composed of various miniature resource-constrained wireless sensor nodes. The development of routing protocols for WSNs is a major challenge because of their severe resource constraints, ad hoc topology and dynamic nature. Among those proposed routing protocols, the biology-inspired self-organized secure autonomous routing protocol (BIOSARP) involves an artificial immune system (AIS) that requires a certain amount of time to build up knowledge of neighboring nodes. The AIS algorithm uses this knowledge to distinguish between self and non-self neighboring nodes. The knowledge-building phase is a critical period in the WSN lifespan and requires active security measures. This paper proposes an enhanced BIOSARP (E-BIOSARP) that incorporates a random key encryption mechanism in a cost-effective manner to provide active security measures in WSNs. A detailed description of E-BIOSARP is presented, followed by an extensive security and performance analysis to demonstrate its efficiency. A scenario with E-BIOSARP is implemented in network simulator 2 (ns-2) and is populated with malicious nodes for analysis. Furthermore, E-BIOSARP is compared with state-of-the-art secure routing protocols in terms of processing time, delivery ratio, energy consumption, and packet overhead. The findings show that the proposed mechanism can efficiently protect WSNs from selective forwarding, brute-force or exhaustive key search, spoofing, eavesdropping, replaying or altering of routing information, cloning, acknowledgment spoofing, HELLO flood attacks, and Sybil attacks. PMID:27043572

  7. Cost-Effective Encryption-Based Autonomous Routing Protocol for Efficient and Secure Wireless Sensor Networks.

    PubMed

    Saleem, Kashif; Derhab, Abdelouahid; Orgun, Mehmet A; Al-Muhtadi, Jalal; Rodrigues, Joel J P C; Khalil, Mohammed Sayim; Ali Ahmed, Adel

    2016-03-31

    The deployment of intelligent remote surveillance systems depends on wireless sensor networks (WSNs) composed of various miniature resource-constrained wireless sensor nodes. The development of routing protocols for WSNs is a major challenge because of their severe resource constraints, ad hoc topology and dynamic nature. Among those proposed routing protocols, the biology-inspired self-organized secure autonomous routing protocol (BIOSARP) involves an artificial immune system (AIS) that requires a certain amount of time to build up knowledge of neighboring nodes. The AIS algorithm uses this knowledge to distinguish between self and non-self neighboring nodes. The knowledge-building phase is a critical period in the WSN lifespan and requires active security measures. This paper proposes an enhanced BIOSARP (E-BIOSARP) that incorporates a random key encryption mechanism in a cost-effective manner to provide active security measures in WSNs. A detailed description of E-BIOSARP is presented, followed by an extensive security and performance analysis to demonstrate its efficiency. A scenario with E-BIOSARP is implemented in network simulator 2 (ns-2) and is populated with malicious nodes for analysis. Furthermore, E-BIOSARP is compared with state-of-the-art secure routing protocols in terms of processing time, delivery ratio, energy consumption, and packet overhead. The findings show that the proposed mechanism can efficiently protect WSNs from selective forwarding, brute-force or exhaustive key search, spoofing, eavesdropping, replaying or altering of routing information, cloning, acknowledgment spoofing, HELLO flood attacks, and Sybil attacks.

  8. Systematic lossy error protection for video transmission over wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoqing; Rane, Shantanu; Girod, Bernd

    2005-07-01

    Wireless ad hoc networks present a challenge for error-resilient video transmission, since node mobility and multipath fading result in time-varying link qualities in terms of packet loss ratio and available bandwidth. In this paper, we propose to use a systematic lossy error protection (SLEP) scheme for video transmission over wireless ad hoc networks. The transmitted video signal has two parts-a systematic portion consisting of a video sequence transmitted without channel coding over an error-prone channel, and error protection information consisting of a bitstream generated by Wyner-Ziv encoding of the video sequence. Using an end-to-end video distortion model in conjunction with online estimates of packet loss ratio and available bandwidth, the optimal Wyner-Ziv description can be selected dynamically according to current channel conditions. The scheme can also be applied to choose one path for transmission from amongst multiple candidate routes with varying available bandwidths and packet loss ratios, so that the expected end-to-end video distortion is maximized. Experimental results of video transmission over a simulated ad hoc wireless network shows that the proposed SLEP scheme outperforms the conventional application layer FEC approach in that it provides graceful degradation of received video quality over a wider range of packet loss ratios and is less susceptible to inaccuracy in the packet loss ratio estimation.

  9. New Routing Metrics for ADHOC Network Routing Protocols

    NASA Astrophysics Data System (ADS)

    Reddy, P. C.

    2014-12-01

    The performance and reliability of Internet is measured using different quantities. When the quantities measured are essential and have wide range of acceptance then they are called metrics. Performance metrics enable comparison and selection among the alternatives. In computer networks, metrics are used to evaluate an application, protocol etc. Routing in adhoc networks is nontrivial. Routing protocols for adhoc networks are still evolving and there is need for continuous evaluation of them. In the literature existing, several routing protocols are evaluated using standard metrics under different conditions. This paper proposes new metrics for evaluation of routing protocols and uses them to evaluate the adhoc network routing protocols AODV, DSR, DSDV and TORA. Simulation environment is created using NS-2 simulator. Typical range of speeds, pause times and data rates are used. The results provide new insights in to the working of the routing protocols.

  10. Shuttle-run synchronization in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Ma, Sheng-Fei; Bi, Hong-Jie; Zou, Yong; Liu, Zong-Hua; Guan, Shu-Guang

    2015-06-01

    In this work, we study the collective dynamics of phase oscillators in a mobile ad hoc network whose topology changes dynamically. As the network size or the communication radius of individual oscillators increases, the topology of the ad hoc network first undergoes percolation, forming a giant cluster, and then gradually achieves global connectivity. It is shown that oscillator mobility generally enhances the coherence in such networks. Interestingly, we find a new type of phase synchronization/clustering, in which the phases of the oscillators are distributed in a certain narrow range, while the instantaneous frequencies change signs frequently, leading to shuttle-run-like motion of the oscillators in phase space. We conduct a theoretical analysis to explain the mechanism of this synchronization and obtain the critical transition point.

  11. MWAHCA: A Multimedia Wireless Ad Hoc Cluster Architecture

    PubMed Central

    Diaz, Juan R.; Jimenez, Jose M.; Sendra, Sandra

    2014-01-01

    Wireless Ad hoc networks provide a flexible and adaptable infrastructure to transport data over a great variety of environments. Recently, real-time audio and video data transmission has been increased due to the appearance of many multimedia applications. One of the major challenges is to ensure the quality of multimedia streams when they have passed through a wireless ad hoc network. It requires adapting the network architecture to the multimedia QoS requirements. In this paper we propose a new architecture to organize and manage cluster-based ad hoc networks in order to provide multimedia streams. Proposed architecture adapts the network wireless topology in order to improve the quality of audio and video transmissions. In order to achieve this goal, the architecture uses some information such as each node's capacity and the QoS parameters (bandwidth, delay, jitter, and packet loss). The architecture splits the network into clusters which are specialized in specific multimedia traffic. The real system performance study provided at the end of the paper will demonstrate the feasibility of the proposal. PMID:24737996

  12. MWAHCA: a multimedia wireless ad hoc cluster architecture.

    PubMed

    Diaz, Juan R; Lloret, Jaime; Jimenez, Jose M; Sendra, Sandra

    2014-01-01

    Wireless Ad hoc networks provide a flexible and adaptable infrastructure to transport data over a great variety of environments. Recently, real-time audio and video data transmission has been increased due to the appearance of many multimedia applications. One of the major challenges is to ensure the quality of multimedia streams when they have passed through a wireless ad hoc network. It requires adapting the network architecture to the multimedia QoS requirements. In this paper we propose a new architecture to organize and manage cluster-based ad hoc networks in order to provide multimedia streams. Proposed architecture adapts the network wireless topology in order to improve the quality of audio and video transmissions. In order to achieve this goal, the architecture uses some information such as each node's capacity and the QoS parameters (bandwidth, delay, jitter, and packet loss). The architecture splits the network into clusters which are specialized in specific multimedia traffic. The real system performance study provided at the end of the paper will demonstrate the feasibility of the proposal.

  13. Performance Impacts of Lower-Layer Cryptographic Methods in Mobile Wireless Ad Hoc Networks

    SciTech Connect

    VAN LEEUWEN, BRIAN P.; TORGERSON, MARK D.

    2002-10-01

    In high consequence systems, all layers of the protocol stack need security features. If network and data-link layer control messages are not secured, a network may be open to adversarial manipulation. The open nature of the wireless channel makes mobile wireless mobile ad hoc networks (MANETs) especially vulnerable to control plane manipulation. The objective of this research is to investigate MANET performance issues when cryptographic processing delays are applied at the data-link layer. The results of analysis are combined with modeling and simulation experiments to show that network performance in MANETs is highly sensitive to the cryptographic overhead.

  14. An Investigation into the Advantages, Mechanisms, and Developmental Challenges of Scripted Mobile Routing

    DTIC Science & Technology

    2008-03-01

    Request for Comments 3561, The Internet Society, July 2003. [3] J. Macker and S. Corson . Mobile ad hoc networks (MANET). http://www.ietf.org...html.charters/manet-charter.html, 1997. IETF Working Group Charter. [4] S. Corson , J. Macker, “Mobile Ad hoc Networking (MANET): Routing Protocol...Performance Issues and Evaluation Considerations,” Network Working Group, Request for Comments 2501, January 1999 [5] Elizabeth . M. Royer, Chai-Keong Toh

  15. 75 FR 15742 - NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-30

    ... SPACE ADMINISTRATION NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting AGENCY... Administration announces a meeting of the Ad-Hoc Task Force on Planetary Defense of the NASA Advisory Council... include: Ad-Hoc Task Force on Planetary Defense Terms of Reference. NASA Near Earth Object (NEO)...

  16. 29 CFR 1912.11 - Terms of ad hoc committee members.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Terms of ad hoc committee members. 1912.11 Section 1912.11..., DEPARTMENT OF LABOR (CONTINUED) ADVISORY COMMITTEES ON STANDARDS Organizational Matters § 1912.11 Terms of ad hoc committee members. Each member of an ad hoc advisory committee shall serve for such period as...

  17. 75 FR 43565 - NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-26

    ... SPACE ADMINISTRATION NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting AGENCY... Administration announces a two-part meeting of the Ad-Hoc Task Force on Planetary Defense of the NASA Advisory...@nasa.gov . SUPPLEMENTARY INFORMATION: The agenda topic is: Drafting of the Ad-Hoc Task Force...

  18. 29 CFR 1912.11 - Terms of ad hoc committee members.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Terms of ad hoc committee members. 1912.11 Section 1912.11..., DEPARTMENT OF LABOR (CONTINUED) ADVISORY COMMITTEES ON STANDARDS Organizational Matters § 1912.11 Terms of ad hoc committee members. Each member of an ad hoc advisory committee shall serve for such period as...

  19. Routing Protocols in Wireless Sensor Networks

    PubMed Central

    Villalba, Luis Javier García; Orozco, Ana Lucila Sandoval; Cabrera, Alicia Triviño; Abbas, Cláudia Jacy Barenco

    2009-01-01

    The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks. PMID:22291515

  20. Ubiquitous and Secure Certificate Service for Wireless Ad Hoc Network

    NASA Astrophysics Data System (ADS)

    Ge, Meng; Lam, Kwok-Yan; Li, Jianbin; Chung, Siu-Leung

    Wireless ad hoc network is one of the most suitable platforms for providing communication services to support mobile applications in public areas where no fixed communication infrastructure exists. However, due to the open nature of wireless links and lack of security infrastructure in an ad hoc network environment, applications operating on ad hoc network platforms are subjected to non-trivial security challenges. Asymmetric key management, which is widely adopted to be an effective basis for security services in an open network environment, typically plays a crucial role in meeting the security requirements of such applications. In this paper, we propose a secure asymmetric key management scheme, the Ubiquitous and Secure Certificate Service (USCS), which is based on a variant of the Distributed Certificate Authority (DCA) - the Fully Distributed Certificate Authority (FDCA). Similar to FDCA, USCS introduces the presence of 1-hop neighbors which hold shares of DCA's private signature key, and can collaborate to issue certificates, thereby providing asymmetric key management service. Both USCS and FDCA aim to achieve higher availability than the basic DCA scheme; however, USCS is more secure than FDCA in that the former achieves high availability by distributing existing shares to new members, rather than generating new shares as the FDCA scheme does. In order to realise the high availability potential of USCS, a share selection algorithm is also proposed. Experimental results demonstrated that USCS is a more secure approach of the DCA scheme in that it can achieve stronger security than FDCA while attaining high availability similar to that of FDCA. Experiments also showed that USCS incurs only moderate communication overheads.

  1. Scalable Architecture for Multihop Wireless ad Hoc Networks

    NASA Technical Reports Server (NTRS)

    Arabshahi, Payman; Gray, Andrew; Okino, Clayton; Yan, Tsun-Yee

    2004-01-01

    A scalable architecture for wireless digital data and voice communications via ad hoc networks has been proposed. Although the details of the architecture and of its implementation in hardware and software have yet to be developed, the broad outlines of the architecture are fairly clear: This architecture departs from current commercial wireless communication architectures, which are characterized by low effective bandwidth per user and are not well suited to low-cost, rapid scaling in large metropolitan areas. This architecture is inspired by a vision more akin to that of more than two dozen noncommercial community wireless networking organizations established by volunteers in North America and several European countries.

  2. A Survey on Trust Management for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2011-11-01

    accumulate between these entities.” Capra [34] proposes to use a human trust model based on human interactions in a trust model for fully distributed...network environments such as MANETs. Capra defines trust as the degree of a belief about the behavior of other entities (or agents). Li and Singhal [35...2004. [34] L. Capra , “Toward a Human Trust Model for Mobile Ad-hoc Net- works,” Proc. 2nd UK-UbiNet Workshop, 5-7 May 2004, Cambridge University

  3. Ground-based observations and AD HOC models

    NASA Astrophysics Data System (ADS)

    Ground based observations of B stars in the visible, the infrared, and the radio region are described along with the ad hoc models proposed to interpret them. It is shown that these observations refer essentially to the photosphere and to the regions of the outer atmosphere where the gas is cool and at low velocity. The characteristics of the variability of the continuous and line spectrum are examined in general and in the cases of individual stars. Finally, linear polarization in the B stars is discussed.

  4. Approximate ad-hoc query engine for simulation data

    SciTech Connect

    Abdulla, G; Baldwin, C; Critchlow, T; Kamimura, R; Lozares, I; Musick, R; Tang, N; Lee, B S; Snapp, R

    2001-02-01

    In this paper, we describe AQSim, an ongoing effort to design and implement a system to manage terabytes of scientific simulation data. The goal of this project is to reduce data storage requirements and access times while permitting ad-hoc queries using statistical and mathematical models of the data. In order to facilitate data exchange between models based on different representations, we are evaluating using the ASCI common data model which is comprised of several layers of increasing semantic complexity. To support queries over the spatial-temporal mesh structured data we are in the process of defining and implementing a grammar for MeshSQL.

  5. On the MAC/Network/Energy Performance Evaluation of Wireless Sensor Networks: Contrasting MPH, AODV, DSR and ZTR Routing Protocols

    PubMed Central

    Del-Valle-Soto, Carolina; Mex-Perera, Carlos; Orozco-Lugo, Aldo; Lara, Mauricio; Galván-Tejada, Giselle M.; Olmedo, Oscar

    2014-01-01

    Wireless Sensor Networks deliver valuable information for long periods, then it is desirable to have optimum performance, reduced delays, low overhead, and reliable delivery of information. In this work, proposed metrics that influence energy consumption are used for a performance comparison among our proposed routing protocol, called Multi-Parent Hierarchical (MPH), the well-known protocols for sensor networks, Ad hoc On-Demand Distance Vector (AODV), Dynamic Source Routing (DSR), and Zigbee Tree Routing (ZTR), all of them working with the IEEE 802.15.4 MAC layer. Results show how some communication metrics affect performance, throughput, reliability and energy consumption. It can be concluded that MPH is an efficient protocol since it reaches the best performance against the other three protocols under evaluation, such as 19.3% reduction of packet retransmissions, 26.9% decrease of overhead, and 41.2% improvement on the capacity of the protocol for recovering the topology from failures with respect to AODV protocol. We implemented and tested MPH in a real network of 99 nodes during ten days and analyzed parameters as number of hops, connectivity and delay, in order to validate our simulator and obtain reliable results. Moreover, an energy model of CC2530 chip is proposed and used for simulations of the four aforementioned protocols, showing that MPH has 15.9% reduction of energy consumption with respect to AODV, 13.7% versus DSR, and 5% against ZTR. PMID:25474377

  6. On the MAC/network/energy performance evaluation of Wireless Sensor Networks: Contrasting MPH, AODV, DSR and ZTR routing protocols.

    PubMed

    Del-Valle-Soto, Carolina; Mex-Perera, Carlos; Orozco-Lugo, Aldo; Lara, Mauricio; Galván-Tejada, Giselle M; Olmedo, Oscar

    2014-12-02

    Wireless Sensor Networks deliver valuable information for long periods, then it is desirable to have optimum performance, reduced delays, low overhead, and reliable delivery of information. In this work, proposed metrics that influence energy consumption are used for a performance comparison among our proposed routing protocol, called Multi-Parent Hierarchical (MPH), the well-known protocols for sensor networks, Ad hoc On-Demand Distance Vector (AODV), Dynamic Source Routing (DSR), and Zigbee Tree Routing (ZTR), all of them working with the IEEE 802.15.4 MAC layer. Results show how some communication metrics affect performance, throughput, reliability and energy consumption. It can be concluded that MPH is an efficient protocol since it reaches the best performance against the other three protocols under evaluation, such as 19.3% reduction of packet retransmissions, 26.9% decrease of overhead, and 41.2% improvement on the capacity of the protocol for recovering the topology from failures with respect to AODV protocol. We implemented and tested MPH in a real network of 99 nodes during ten days and analyzed parameters as number of hops, connectivity and delay, in order to validate our Sensors 2014, 14 22812 simulator and obtain reliable results. Moreover, an energy model of CC2530 chip is proposed and used for simulations of the four aforementioned protocols, showing that MPH has 15.9% reduction of energy consumption with respect to AODV, 13.7% versus DSR, and 5% against ZTR.

  7. Topology for efficient information dissemination in ad-hoc networking

    NASA Technical Reports Server (NTRS)

    Jennings, E.; Okino, C. M.

    2002-01-01

    In this paper, we explore the information dissemination problem in ad-hoc wirless networks. First, we analyze the probability of successful broadcast, assuming: the nodes are uniformly distributed, the available area has a lower bould relative to the total number of nodes, and there is zero knowledge of the overall topology of the network. By showing that the probability of such events is small, we are motivated to extract good graph topologies to minimize the overall transmissions. Three algorithms are used to generate topologies of the network with guaranteed connectivity. These are the minimum radius graph, the relative neighborhood graph and the minimum spanning tree. Our simulation shows that the relative neighborhood graph has certain good graph properties, which makes it suitable for efficient information dissemination.

  8. Remote Upload of Evidence over Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Ray, Indrajit

    In this work, we report on one aspect of an autonomous robot-based digital evidence acquisition system that we are developing. When forensic investigators operate within a hostile environment they may use remotely operated unmanned devices to gather digital evidence. These systems periodically upload the evidence to a remote central server using a mobile ad hoc network. In such cases, large pieces of information need to be fragmented and transmitted in an appropriate manner. To support proper forensic analysis, certain properties must ensured for each fragment of evidence — confidentiality during communication, authenticity and integrity of the data, and, most importantly, strong evidence of membership for fragments. This paper describes a framework to provide these properties for the robot-based evidence acquisition system under development.

  9. Ad hoc committee on global climate issues: Annual report

    USGS Publications Warehouse

    Gerhard, L.C.; Hanson, B.M.B.

    2000-01-01

    The AAPG Ad Hoc Committee on Global Climate Issues has studied the supposition of human-induced climate change since the committee's inception in January 1998. This paper details the progress and findings of the committee through June 1999. At that time there had been essentially no geologic input into the global climate change debate. The following statements reflect the current state of climate knowledge from the geologic perspective as interpreted by the majority of the committee membership. The committee recognizes that new data could change its conclusions. The earth's climate is constantly changing owing to natural variability in earth processes. Natural climate variability over recent geological time is greater than reasonable estimates of potential human-induced greenhouse gas changes. Because no tool is available to test the supposition of human-induced climate change and the range of natural variability is so great, there is no discernible human influence on global climate at this time.

  10. Opportunistic Channel Scheduling for Ad Hoc Networks with Queue Stability

    NASA Astrophysics Data System (ADS)

    Dong, Lei; Wang, Yongchao

    2015-03-01

    In this paper, a distributed opportunistic channel access strategy in ad hoc network is proposed. We consider the multiple sources contend for the transmission opportunity, the winner source decides to transmit or restart contention based on the current channel condition. Owing to real data assumption at all links, the decision still needs to consider the stability of the queues. We formulate the channel opportunistic scheduling as a constrained optimization problem which maximizes the system average throughput with the constraints that the queues of all links are stable. The proposed optimization model is solved by Lyapunov stability in queueing theory. The successive channel access problem is decoupled into single optimal stopping problem at every frame and solved with Lyapunov algorithm. The threshold for every frame is different, and it is derived based on the instantaneous queue information. Finally, computer simulations are conducted to demonstrate the validity of the proposed strategy.

  11. Undilatable Stent Neoatherosclerosis Treated with Ad Hoc Rotational Atherectomy

    PubMed Central

    Koutouzis, Michael; Maniotis, Christos; Tsiafoutis, Ioannis; Argyriou, Mihalis

    2017-01-01

    A middle age woman with known ischemic heart disease and old stents in proximal left anterior descending coronary artery (LAD) was admitted to Coronary Care Unit with acute coronary syndrome. The coronary angiography showed one vessel disease with significant restenosis within the previously implanted stents. The lesion was tough and remained undilatable despite high pressure balloon inflation. Eventually, the balloon ruptured creating a massive dissection of the LAD beginning immediately after the distal part of the undilatable lesion. We proceeded with a challenging ad hoc rotational atherectomy of the lesion and finally stenting of the lesion. In-stent restenosis many years after stent implantation is considered to be mainly due to neoatheromatosis compared to intimal hyperplasia, making lesion treatment more difficult and unpredictable. PMID:28168062

  12. A New Distributed Routing Protocol.

    DTIC Science & Technology

    1984-01-01

    Kindm ’[t., BMnclh CntMU Consider a attuatJion in %, Adhd them am n n es0 ndh lidkd to at least ne &her node sudh that all moe a wwmwted. either...distributed Itn r that is cpable, of failsafe distributed routing. 37 ~L MANHATAN %SQ.ARE GP :,!: NETWORK, - CONNECTTVY S . .. . I ip p- t 0 4 Figure 4-3

  13. Secure Adaptive Topology Control for Wireless Ad-Hoc Sensor Networks

    PubMed Central

    Hsueh, Ching-Tsung; Li, Yu-Wei; Wen, Chih-Yu; Ouyang, Yen-Chieh

    2010-01-01

    This paper presents a secure decentralized clustering algorithm for wireless ad-hoc sensor networks. The algorithm operates without a centralized controller, operates asynchronously, and does not require that the location of the sensors be known a priori. Based on the cluster-based topology, secure hierarchical communication protocols and dynamic quarantine strategies are introduced to defend against spam attacks, since this type of attacks can exhaust the energy of sensor nodes and will shorten the lifetime of a sensor network drastically. By adjusting the threshold of infected percentage of the cluster coverage, our scheme can dynamically coordinate the proportion of the quarantine region and adaptively achieve the cluster control and the neighborhood control of attacks. Simulation results show that the proposed approach is feasible and cost effective for wireless sensor networks. PMID:22205866

  14. A User Authentication Scheme Based on Elliptic Curves Cryptography for Wireless Ad Hoc Networks.

    PubMed

    Chen, Huifang; Ge, Linlin; Xie, Lei

    2015-07-14

    The feature of non-infrastructure support in a wireless ad hoc network (WANET) makes it suffer from various attacks. Moreover, user authentication is the first safety barrier in a network. A mutual trust is achieved by a protocol which enables communicating parties to authenticate each other at the same time and to exchange session keys. For the resource-constrained WANET, an efficient and lightweight user authentication scheme is necessary. In this paper, we propose a user authentication scheme based on the self-certified public key system and elliptic curves cryptography for a WANET. Using the proposed scheme, an efficient two-way user authentication and secure session key agreement can be achieved. Security analysis shows that our proposed scheme is resilient to common known attacks. In addition, the performance analysis shows that our proposed scheme performs similar or better compared with some existing user authentication schemes.

  15. A User Authentication Scheme Based on Elliptic Curves Cryptography for Wireless Ad Hoc Networks

    PubMed Central

    Chen, Huifang; Ge, Linlin; Xie, Lei

    2015-01-01

    The feature of non-infrastructure support in a wireless ad hoc network (WANET) makes it suffer from various attacks. Moreover, user authentication is the first safety barrier in a network. A mutual trust is achieved by a protocol which enables communicating parties to authenticate each other at the same time and to exchange session keys. For the resource-constrained WANET, an efficient and lightweight user authentication scheme is necessary. In this paper, we propose a user authentication scheme based on the self-certified public key system and elliptic curves cryptography for a WANET. Using the proposed scheme, an efficient two-way user authentication and secure session key agreement can be achieved. Security analysis shows that our proposed scheme is resilient to common known attacks. In addition, the performance analysis shows that our proposed scheme performs similar or better compared with some existing user authentication schemes. PMID:26184224

  16. Ad-Hoc Queries over Document Collections - A Case Study

    NASA Astrophysics Data System (ADS)

    Löser, Alexander; Lutter, Steffen; Düssel, Patrick; Markl, Volker

    We discuss the novel problem of supporting analytical business intelligence queries over web-based textual content, e.g., BI-style reports based on 100.000's of documents from an ad-hoc web search result. Neither conventional search engines nor conventional Business Intelligence and ETL tools address this problem, which lies at the intersection of their capabilities. "Google Squared" or our system GOOLAP.info, are examples of these kinds of systems. They execute information extraction methods over one or several document collections at query time and integrate extracted records into a common view or tabular structure. Frequent extraction and object resolution failures cause incomplete records which could not be joined into a record answering the query. Our focus is the identification of join-reordering heuristics maximizing the size of complete records answering a structured query. With respect to given costs for document extraction we propose two novel join-operations: The multi-way CJ-operator joins records from multiple relationships extracted from a single document. The two-way join-operator DJ ensures data density by removing incomplete records from results. In a preliminary case study we observe that our join-reordering heuristics positively impact result size, record density and lower execution costs.

  17. Z306 molecular contamination ad hoc committee results

    NASA Technical Reports Server (NTRS)

    Golden, Johnny L.

    1992-01-01

    LDEF external surfaces which did not receive significant amounts of atomic oxygen were observed to be coated with a brown contamination, apparently the result of a condensed organic residue darkened due to UV radiation exposure. During the initial Materials Special Investigation Group (MSIG) Meeting after LDEF deintegration, held in Seattle - July 1990, this organic contamination was the subject of much discussion. The amount of contamination was thought to be significant and its source was immediately believed to be the Z306 black thermal control coating used to coat the entire inner surface of LDEF. Due to the size of the structure, it was not feasible to bake-out the coating. However, initial data on the contamination film was confusing in that significant amounts of silicon was observed by several different researchers. Silicon (from silicone) was not expected to be a potential outgassing product of the Z306 polyurethane coating. To investigate the connection between external contamination and the interior paint, a MSIG ad hoc committee was formed.

  18. Random Time Identity Based Firewall In Mobile Ad hoc Networks

    NASA Astrophysics Data System (ADS)

    Suman, Patel, R. B.; Singh, Parvinder

    2010-11-01

    A mobile ad hoc network (MANET) is a self-organizing network of mobile routers and associated hosts connected by wireless links. MANETs are highly flexible and adaptable but at the same time are highly prone to security risks due to the open medium, dynamically changing network topology, cooperative algorithms, and lack of centralized control. Firewall is an effective means of protecting a local network from network-based security threats and forms a key component in MANET security architecture. This paper presents a review of firewall implementation techniques in MANETs and their relative merits and demerits. A new approach is proposed to select MANET nodes at random for firewall implementation. This approach randomly select a new node as firewall after fixed time and based on critical value of certain parameters like power backup. This approach effectively balances power and resource utilization of entire MANET because responsibility of implementing firewall is equally shared among all the nodes. At the same time it ensures improved security for MANETs from outside attacks as intruder will not be able to find out the entry point in MANET due to the random selection of nodes for firewall implementation.

  19. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Designation of chairperson for Ad Hoc Committees... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  20. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Designation of chairperson for Ad Hoc Committees... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  1. Typicality Mediates Performance during Category Verification in Both Ad-Hoc and Well-Defined Categories

    ERIC Educational Resources Information Center

    Sandberg, Chaleece; Sebastian, Rajani; Kiran, Swathi

    2012-01-01

    Background: The typicality effect is present in neurologically intact populations for natural, ad-hoc, and well-defined categories. Although sparse, there is evidence of typicality effects in persons with chronic stroke aphasia for natural and ad-hoc categories. However, it is unknown exactly what influences the typicality effect in this…

  2. Preferential survival in models of complex ad hoc networks

    NASA Astrophysics Data System (ADS)

    Kong, Joseph S.; Roychowdhury, Vwani P.

    2008-05-01

    There has been a rich interplay in recent years between (i) empirical investigations of real-world dynamic networks, (ii) analytical modeling of the microscopic mechanisms that drive the emergence of such networks, and (iii) harnessing of these mechanisms to either manipulate existing networks, or engineer new networks for specific tasks. We continue in this vein, and study the deletion phenomenon in the web by the following two different sets of websites (each comprising more than 150,000 pages) over a one-year period. Empirical data show that there is a significant deletion component in the underlying web networks, but the deletion process is not uniform. This motivates us to introduce a new mechanism of preferential survival (PS), where nodes are removed according to the degree-dependent deletion kernel, D(k)∝k, with α≥0. We use the mean-field rate equation approach to study a general dynamic model driven by Preferential Attachment (PA), Double PA (DPA), and a tunable PS (i.e., with any α>0), where c nodes ( c<1) are deleted per node added to the network, and verify our predictions via large-scale simulations. One of our results shows that, unlike in the case of uniform deletion (i.e., where α=0), the PS kernel when coupled with the standard PA mechanism, can lead to heavy-tailed power-law networks even in the presence of extreme turnover in the network. Moreover, a weak DPA mechanism, coupled with PS, can help to make the network even more heavy-tailed, especially in the limit when deletion and insertion rates are almost equal, and the overall network growth is minimal. The dynamics reported in this work can be used to design and engineer stable ad hoc networks and explain the stability of the power-law exponents observed in real-world networks.

  3. Data Delivery Method Based on Neighbor Nodes' Information in a Mobile Ad Hoc Network

    PubMed Central

    Hayashi, Takuma; Taenaka, Yuzo; Okuda, Takeshi; Yamaguchi, Suguru

    2014-01-01

    This paper proposes a data delivery method based on neighbor nodes' information to achieve reliable communication in a mobile ad hoc network (MANET). In a MANET, it is difficult to deliver data reliably due to instabilities in network topology and wireless network condition which result from node movement. To overcome such unstable communication, opportunistic routing and network coding schemes have lately attracted considerable attention. Although an existing method that employs such schemes, MAC-independent opportunistic routing and encoding (MORE), Chachulski et al. (2007), improves the efficiency of data delivery in an unstable wireless mesh network, it does not address node movement. To efficiently deliver data in a MANET, the method proposed in this paper thus first employs the same opportunistic routing and network coding used in MORE and also uses the location information and transmission probabilities of neighbor nodes to adapt to changeable network topology and wireless network condition. The simulation experiments showed that the proposed method can achieve efficient data delivery with low network load when the movement speed is relatively slow. PMID:24672371

  4. Does Ad Hoc Coronary Intervention Reduce Radiation Exposure? – Analysis of 568 Patients

    PubMed Central

    Truffa, Márcio A. M.; Alves, Gustavo M.P.; Bernardi, Fernando; Esteves Filho, Antonio; Ribeiro, Expedito; Galon, Micheli Z.; Spadaro, André; Kajita, Luiz J.; Arrieta, Raul; Lemos, Pedro A.

    2015-01-01

    Background Advantages and disadvantages of ad hoc percutaneous coronary intervention have been described. However little is known about the radiation exposure of that procedure as compared with the staged intervention. Objective To compare the radiation dose of the ad hoc percutaneous coronary intervention with that of the staged procedure Methods The dose-area product and total Kerma were measured, and the doses of the diagnostic and therapeutic procedures were added. In addition, total fluoroscopic time and number of acquisitions were evaluated. Results A total of 568 consecutive patients were treated with ad hoc percutaneous coronary intervention (n = 320) or staged percutaneous coronary intervention (n = 248). On admission, the ad hoc group had less hypertension (74.1% vs 81.9%; p = 0.035), dyslipidemia (57.8% vs. 67.7%; p = 0.02) and three-vessel disease (38.8% vs. 50.4%; p = 0.015). The ad hoc group was exposed to significantly lower radiation doses, even after baseline characteristic adjustment between both groups. The ad hoc group was exposed to a total dose-area product of 119.7 ± 70.7 Gycm2, while the staged group, to 139.2 ± 75.3 Gycm2 (p < 0.001). Conclusion Ad hoc percutaneous coronary intervention reduced radiation exposure as compared with diagnostic and therapeutic procedures performed at two separate times. PMID:26351982

  5. A Threshold-Adaptive Reputation System on Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Tsai, Hsiao-Chien; Lo, Nai-Wei; Wu, Tzong-Chen

    In recent years huge potential benefits from novel applications in mobile ad hoc networks (MANET) have been discussed extensively. However, without robust security mechanisms and systems to provide safety shell through the MANET infrastructure, MANET applications can be vulnerable and hammered by malicious attackers easily. In order to detect misbehaved message routing and identify malicious attackers in MANET, schemes based on reputation concept have shown their advantages in this area in terms of good scalability and simple threshold-based detection strategy. We observed that previous reputation schemes generally use predefined thresholds which do not take into account the effect of behavior dynamics between nodes in a period of time. In this paper, we propose a Threshold-Adaptive Reputation System (TARS) to overcome the shortcomings of static threshold strategy and improve the overall MANET performance under misbehaved routing attack. A fuzzy-based inference engine is introduced to evaluate the trustiness of a node's one-hop neighbors. Malicious nodes whose trust values are lower than the adaptive threshold, will be detected and filtered out by their honest neighbors during trustiness evaluation process. The results of network simulation show that the TARS outperforms other compared schemes under security attacks in most cases and at the same time reduces the decrease of total packet delivery ratio by 67% in comparison with MANET without reputation system.

  6. A Survey on Underwater Acoustic Sensor Network Routing Protocols

    PubMed Central

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-01-01

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research. PMID:27011193

  7. A Survey on Underwater Acoustic Sensor Network Routing Protocols.

    PubMed

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-03-22

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research.

  8. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  9. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  10. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  11. Voice Communications over 802.11 Ad Hoc Networks: Modeling, Optimization and Call Admission Control

    NASA Astrophysics Data System (ADS)

    Xu, Changchun; Xu, Yanyi; Liu, Gan; Liu, Kezhong

    Supporting quality-of-service (QoS) of multimedia communications over IEEE 802.11 based ad hoc networks is a challenging task. This paper develops a simple 3-D Markov chain model for queuing analysis of IEEE 802.11 MAC layer. The model is applied for performance analysis of voice communications over IEEE 802.11 single-hop ad hoc networks. By using the model, we finish the performance optimization of IEEE MAC layer and obtain the maximum number of voice calls in IEEE 802.11 ad hoc networks as well as the statistical performance bounds. Furthermore, we design a fully distributed call admission control (CAC) algorithm which can provide strict statistical QoS guarantee for voice communications over IEEE 802.11 ad hoc networks. Extensive simulations indicate the accuracy of the analytical model and the CAC scheme.

  12. A Group Based Key Sharing and Management Algorithm for Vehicular Ad Hoc Networks

    PubMed Central

    Moharram, Mohammed Morsi; Azam, Farzana

    2014-01-01

    Vehicular ad hoc networks (VANETs) are one special type of ad hoc networks that involves vehicles on roads. Typically like ad hoc networks, broadcast approach is used for data dissemination. Blind broadcast to each and every node results in exchange of useless and irrelevant messages and hence creates an overhead. Unicasting is not preferred in ad-hoc networks due to the dynamic topology and the resource requirements as compared to broadcasting. Simple broadcasting techniques create several problems on privacy, disturbance, and resource utilization. In this paper, we propose media mixing algorithm to decide what information should be provided to each user and how to provide such information. Results obtained through simulation show that fewer number of keys are needed to share compared to simple broadcasting. Privacy is also enhanced through this approach. PMID:24587749

  13. A group based key sharing and management algorithm for vehicular ad hoc networks.

    PubMed

    Khan, Zeeshan Shafi; Moharram, Mohammed Morsi; Alaraj, Abdullah; Azam, Farzana

    2014-01-01

    Vehicular ad hoc networks (VANETs) are one special type of ad hoc networks that involves vehicles on roads. Typically like ad hoc networks, broadcast approach is used for data dissemination. Blind broadcast to each and every node results in exchange of useless and irrelevant messages and hence creates an overhead. Unicasting is not preferred in ad-hoc networks due to the dynamic topology and the resource requirements as compared to broadcasting. Simple broadcasting techniques create several problems on privacy, disturbance, and resource utilization. In this paper, we propose media mixing algorithm to decide what information should be provided to each user and how to provide such information. Results obtained through simulation show that fewer number of keys are needed to share compared to simple broadcasting. Privacy is also enhanced through this approach.

  14. Cross-Layered Security Analysis of Wireless Ad Hoc Networks

    DTIC Science & Technology

    2004-12-01

    considerations. Some possible attacks include route disruption attacks such as routing loops, sink holes ( black holes , grey holes , etc.), sub optimal...attempt to jam the communications channel, they can create a wormhole , and as an extreme attack, we assume they can eliminate nodes from the network...spectrum technology and codes resilient to malicious interference. On the other side, a wormhole is very difficult to prevent. However, when the MAC

  15. Resource Management in Multi-hop Ad Hoc Networks

    DTIC Science & Technology

    1999-11-21

    Communications Review, 27(5), 1996. Read from http://www.ece.orst.edu/s̃ingh/papers.html. [8] M. Scott Corson and Anthony Ephremides. A Distributed Routing...France, October 1997. [32] Vincent D. Park and M. Scott Corson . A Highly Adaptive Distributed Routing Algorithm for Mobile Wireless Networks. In...Proceedings of INFOCOM’97, pages 1405–1413, April 1997. [33] Vincent D. Park and M. Scott Corson . A Performance Comparison of TORA and Ideal Link State

  16. Scalable Mobile Ad Hoc Network (MANET) to Enhance Situational Awareness in Distributed Small Unit Operations

    DTIC Science & Technology

    2015-06-01

    saying that he has called for “a network that would allow soldiers to tap their laptop or smart phone keyboards and obtain the information they need, as...AD HOC NETWORK (MANET) TO ENHANCE SITUATIONAL AWARENESS IN DISTRIBUTED SMALL UNIT OPERATIONS by Jonathan Clarke Driesslein June 2015...REPORT DATE June 2015 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE SCALABLE MOBILE AD HOC NETWORK (MANET) TO

  17. Improving English and Chinese Ad-hoc Retrieval: Tipster Text Phase 3

    DTIC Science & Technology

    1998-10-01

    IMPROVING ENGLISH AND CHINESE AD-HOC RETRIEVAL: TIPSTER TEXT PHASE 3 FINAL REPORT Kui-Lam Kwok Computer Science Department, Queens College, CUNY...all past TREC experiments with consistently superior results. Since 1996, we have also participated in the TIPSTER Text Phase 3 program. This...COVERED 00-00-1998 to 00-00-1998 4. TITLE AND SUBTITLE Improving English and Chinese Ad-hoc Retrieval: TIPSTER Text Phase 3 Final Report 5a

  18. A Game Theory Algorithm for Intra-Cluster Data Aggregation in a Vehicular Ad Hoc Network.

    PubMed

    Chen, Yuzhong; Weng, Shining; Guo, Wenzhong; Xiong, Naixue

    2016-02-19

    Vehicular ad hoc networks (VANETs) have an important role in urban management and planning. The effective integration of vehicle information in VANETs is critical to traffic analysis, large-scale vehicle route planning and intelligent transportation scheduling. However, given the limitations in the precision of the output information of a single sensor and the difficulty of information sharing among various sensors in a highly dynamic VANET, effectively performing data aggregation in VANETs remains a challenge. Moreover, current studies have mainly focused on data aggregation in large-scale environments but have rarely discussed the issue of intra-cluster data aggregation in VANETs. In this study, we propose a multi-player game theory algorithm for intra-cluster data aggregation in VANETs by analyzing the competitive and cooperative relationships among sensor nodes. Several sensor-centric metrics are proposed to measure the data redundancy and stability of a cluster. We then study the utility function to achieve efficient intra-cluster data aggregation by considering both data redundancy and cluster stability. In particular, we prove the existence of a unique Nash equilibrium in the game model, and conduct extensive experiments to validate the proposed algorithm. Results demonstrate that the proposed algorithm has advantages over typical data aggregation algorithms in both accuracy and efficiency.

  19. A Game Theory Algorithm for Intra-Cluster Data Aggregation in a Vehicular Ad Hoc Network

    PubMed Central

    Chen, Yuzhong; Weng, Shining; Guo, Wenzhong; Xiong, Naixue

    2016-01-01

    Vehicular ad hoc networks (VANETs) have an important role in urban management and planning. The effective integration of vehicle information in VANETs is critical to traffic analysis, large-scale vehicle route planning and intelligent transportation scheduling. However, given the limitations in the precision of the output information of a single sensor and the difficulty of information sharing among various sensors in a highly dynamic VANET, effectively performing data aggregation in VANETs remains a challenge. Moreover, current studies have mainly focused on data aggregation in large-scale environments but have rarely discussed the issue of intra-cluster data aggregation in VANETs. In this study, we propose a multi-player game theory algorithm for intra-cluster data aggregation in VANETs by analyzing the competitive and cooperative relationships among sensor nodes. Several sensor-centric metrics are proposed to measure the data redundancy and stability of a cluster. We then study the utility function to achieve efficient intra-cluster data aggregation by considering both data redundancy and cluster stability. In particular, we prove the existence of a unique Nash equilibrium in the game model, and conduct extensive experiments to validate the proposed algorithm. Results demonstrate that the proposed algorithm has advantages over typical data aggregation algorithms in both accuracy and efficiency. PMID:26907272

  20. Enabling Secure High-Performance Wireless Ad Hoc Networking

    DTIC Science & Technology

    2003-05-29

    destinations, consuming energy and available bandwidth. An attacker may similarly create a routing black hole , in which all packets are dropped: by sending...all nodes in an area of the network to point “into” that area when in fact the destination is outside the area. As a special case of a black hole , an...may attempt the following attacks: • Create a gray hole or black hole by removing nodes in a ROUTE REQUEST; however, the per- hop hash mechanism in

  1. Energy-efficient algorithm for broadcasting in ad hoc wireless sensor networks.

    PubMed

    Xiong, Naixue; Huang, Xingbo; Cheng, Hongju; Wan, Zheng

    2013-04-12

    Broadcasting is a common and basic operation used to support various network protocols in wireless networks. To achieve energy-efficient broadcasting is especially important for ad hoc wireless sensor networks because sensors are generally powered by batteries with limited lifetimes. Energy consumption for broadcast operations can be reduced by minimizing the number of relay nodes based on the observation that data transmission processes consume more energy than data reception processes in the sensor nodes, and how to improve the network lifetime is always an interesting issue in sensor network research. The minimum-energy broadcast problem is then equivalent to the problem of finding the minimum Connected Dominating Set (CDS) for a connected graph that is proved NP-complete. In this paper, we introduce an Efficient Minimum CDS algorithm (EMCDS) with help of a proposed ordered sequence list. EMCDS does not concern itself with node energy and broadcast operations might fail if relay nodes are out of energy. Next we have proposed a Minimum Energy-consumption Broadcast Scheme (MEBS) with a modified version of EMCDS, and aimed at providing an efficient scheduling scheme with maximized network lifetime. The simulation results show that the proposed EMCDS algorithm can find smaller CDS compared with related works, and the MEBS can help to increase the network lifetime by efficiently balancing energy among nodes in the networks.

  2. Enhancing the selection of backoff interval using fuzzy logic over wireless Ad Hoc networks.

    PubMed

    Ranganathan, Radha; Kannan, Kathiravan

    2015-01-01

    IEEE 802.11 is the de facto standard for medium access over wireless ad hoc network. The collision avoidance mechanism (i.e., random binary exponential backoff-BEB) of IEEE 802.11 DCF (distributed coordination function) is inefficient and unfair especially under heavy load. In the literature, many algorithms have been proposed to tune the contention window (CW) size. However, these algorithms make every node select its backoff interval between [0, CW] in a random and uniform manner. This randomness is incorporated to avoid collisions among the nodes. But this random backoff interval can change the optimal order and frequency of channel access among competing nodes which results in unfairness and increased delay. In this paper, we propose an algorithm that schedules the medium access in a fair and effective manner. This algorithm enhances IEEE 802.11 DCF with additional level of contention resolution that prioritizes the contending nodes according to its queue length and waiting time. Each node computes its unique backoff interval using fuzzy logic based on the input parameters collected from contending nodes through overhearing. We evaluate our algorithm against IEEE 802.11, GDCF (gentle distributed coordination function) protocols using ns-2.35 simulator and show that our algorithm achieves good performance.

  3. Network Management System for Tactical Mobile Ad Hoc Network Segments

    DTIC Science & Technology

    2011-09-01

    Protocol UFO UHF Follow-On UHF Ultra High Frequency USB Universal Serial Bus VHF Very High Frequency VIRT Valuable Information at the Right Time...military satellite system known as the UHF Follow-on system ( UFO ) only provides capacity for 600 concurrent users. DoD users also have commercial

  4. Typicality Mediates Performance during Category Verification in Both Ad-hoc and Well-defined Categories

    PubMed Central

    Sandberg, Chaleece; Sebastian, Rajani; Kiran, Swathi

    2012-01-01

    Background The typicality effect is present in neurologically intact populations for natural, ad-hoc, and well-defined categories. Although sparse, there is evidence of typicality effects in persons with chronic stroke aphasia for natural and ad-hoc categories. However, it is unknown exactly what influences the typicality effect in this population. Aims The present study explores the possible contributors to the typicality effect in persons with aphasia by analyzing and comparing data from both normal and language-disordered populations, from persons with aphasia with more semantic impairment versus those with less semantic impairment, and from two types of categories with very different boundary structure (ad-hoc vs. well-defined). Methods and procedures A total of 40 neurologically healthy adults (20 older, 20 younger) and 35 persons with aphasia (20 LSI (less-semantically impaired) patients, 15 MSI (more-semantically impaired) patients) participated in the study. Participants completed one of two tasks: either category verification for ad-hoc categories or category verification for well-defined categories. Outcomes and Results Neurologically healthy participants showed typicality effects for both ad-hoc and well-defined categories. MSI patients showed a typicality effect for well-defined categories, but not for ad-hoc categories, whereas LSI patients showed a typicality effect for ad-hoc categories, but not for well-defined categories. Conclusions These results suggest that the degree of semantic impairment mediates the typicality effect in persons with aphasia depending on the structure of the category. PMID:22261305

  5. Detailed analysis of routing protocols with different network limitations

    NASA Astrophysics Data System (ADS)

    Masood, Mohsin; Abuhelala, Mohamed; Glesk, Ivan

    2016-12-01

    In network communication field, routing protocols have got a significant role which are not only used in networks to handle the user data but also to monitor the different network environments. Dynamic routing protocols such as OSPF, EIGRP and RIP are used for forwarding user data to its destination by instantly detecting the dynamic changes across the network. The dynamic changes in the network can be in the form of topological changes, congestions, links failure etc. Therefore, it becomes a challenge to develop and implement dynamic routing protocols that fulfills the network requirements. Hence, each routing protocol has its own characteristics such as convergence activity, routing metric, routing table etc. and will perform differently in various network environments. This paper presents a comprehensive study of static and dynamic routing, along with dynamic routing protocols. Experiments that are conducted under various network limitations are presented using the OPNET tool. The performance of each of dynamic routing protocols are monitored and explained in the form of simulated results using network parameters. The results are analyzed, in order to provide a clear understanding of each protocol performance for the selection of the proper protocol for a given network environment.

  6. A Decentralized VPN Service over Generalized Mobile Ad-Hoc Networks

    NASA Astrophysics Data System (ADS)

    Fujita, Sho; Shima, Keiichi; Uo, Yojiro; Esaki, Hiroshi

    We present a decentralized VPN service that can be built over generalized mobile ad-hoc networks (Generalized MANETs), in which topologies can be represented as a time-varying directed multigraph. We address wireless ad-hoc networks and overlay ad-hoc networks as instances of Generalized MANETs. We first propose an architecture to operate on various kinds of networks through a single set of operations. Then, we design and implement a decentralized VPN service on the proposed architecture. Through the development and operation of a prototype system we implemented, we found that the proposed architecture makes the VPN service applicable to each instance of Generalized MANETs, and that the VPN service makes it possible for unmodified applications to operate on the networks.

  7. A double candidate survivable routing protocol for HAP network

    NASA Astrophysics Data System (ADS)

    He, Panfeng; Li, Chunyue; Ni, Shuyan

    2016-11-01

    To improve HAP network invulnerability, and at the same time considering the quasi-dynamic topology in HAP network, a simple and reliable routing protocol is proposed in the paper. The protocol firstly uses a double-candidate strategy for the next-node select to provide better robustness. Then during the maintenance stage, short hello packets instead of long routing packets are used only to check link connectivity in the quasi-dynamic HAP network. The route maintenance scheme based on short hello packets can greatly reduce link spending. Simulation results based on OPNET demonstrate the effectiveness of the proposed routing protocol.

  8. Constraints and Approaches for Distributed Mobile AD-HOC Network Security

    DTIC Science & Technology

    2005-11-01

    sizes, and scenarios. Protocols such as Identity- Based Symmetric Keying and Rich Uncle have limited application until the network’s routing...optimized group determination algorithm – The algorithm we are currently using is sub -optimal since it simply finds the largest group available, whereas a...that may result in sub -optimal configurations. • Integration of routing and keying protocols – Despite the additional complexity of integrating

  9. From Malicious Eyes: A Method for Concise Representation of Ad-Hoc Networks and Efficient Attack Survivability Analysis

    DTIC Science & Technology

    2012-07-01

    a modification of OSPF that is optimized for mobile ad-hoc networks . OSPFv3MDR uses IPv6 addressing. Topology. In attempts to achieve a suitable...From Malicious Eyes: A Method for Concise Representation of Ad-Hoc Networks and Efficient Attack Survivability Analysis by Jaime C. Acosta...White Sands Missile Range, NM 88002-5501 ARL-TR-6035 July 2012 From Malicious Eyes: A Method for Concise Representation of Ad-Hoc Networks

  10. Analysis of the Robustness Dynamics of Wireless Mobile Ad Hoc Networks via Time Varying Dual Basis Representation

    DTIC Science & Technology

    2015-01-08

    Analysis of the Robustness Dynamics of Wireless Mobile Ad Hoc Networks via Time Varying Dual Basis Representation Thomas Parker, Jamie Johnson...between nodes to analyze the robustness of a wireless mobile ad hoc network (MANET) with a time-varying wireless channel. This spectral analysis and...a single eigenvalue is evaluated. 1. Introduction Mobile ad hoc networks (MANETs) are complex systems that can be foreseen supporting

  11. A Survey on Clustering Routing Protocols in Wireless Sensor Networks

    PubMed Central

    Liu, Xuxun

    2012-01-01

    The past few years have witnessed increased interest in the potential use of wireless sensor networks (WSNs) in a wide range of applications and it has become a hot research area. Based on network structure, routing protocols in WSNs can be divided into two categories: flat routing and hierarchical or clustering routing. Owing to a variety of advantages, clustering is becoming an active branch of routing technology in WSNs. In this paper, we present a comprehensive and fine grained survey on clustering routing protocols proposed in the literature for WSNs. We outline the advantages and objectives of clustering for WSNs, and develop a novel taxonomy of WSN clustering routing methods based on complete and detailed clustering attributes. In particular, we systematically analyze a few prominent WSN clustering routing protocols and compare these different approaches according to our taxonomy and several significant metrics. Finally, we summarize and conclude the paper with some future directions. PMID:23112649

  12. Comparison of two commonly practiced atropinization regimens in acute organophosphorus and carbamate poisoning, doubling doses vs. ad hoc: a prospective observational study.

    PubMed

    Perera, P M S; Shahmy, S; Gawarammana, I; Dawson, A H

    2008-06-01

    There is a wide variation and lack of evidence in current recommendations for atropine dosing schedules leading to subsequent variation in clinical practice. Therefore, we sought to examine the safety and effectiveness of a titrated vs. ad hoc atropine treatment regimen in a cohort of patients with acute cholinesterase inhibitor pesticide poisoning. A prospective cohort study was conducted in three district secondary referral hospitals in Sri Lanka using a structured data collection form that collected details of clinical symptoms and outcomes of cholinesterase inhibitor pesticide poisoning, atropine doses, and signs of atropinization. We compared two hospitals that used a titrated dosing protocol based on a structured monitoring sheet for atropine infusion with another hospital using an ad hoc regime. During the study, 272 symptomatic patients with anticholinesterase poisoning requiring atropine were admitted to the three hospitals. Outcomes of death and ventilation were analyzed for all patients, 226 patients were prospectively assessed for atropine toxicity. At baseline, patients in the titrated dose cohort had clinical signs consistent with greater toxicity. This in part may be due to ingestion of more toxic organophosphates. They received less pralidoxime and atropine, and were less likely to develop features of atropine toxicity, such as delirium (1% vs. 17%), hallucinations (1% vs. 35%), or either (1% vs. 35%) and need for patient restraint (3% vs. 48%) compared with the ad hoc dose regime. After adjusting for the pesticides ingested, there was no difference in mortality and ventilatory rates between protocols. Ad hoc high dose atropine regimens are associated with more frequent atropine toxicity without any obvious improvement in patient outcome compared with doses titrated to clinical effect. Atropine doses should be titrated against response and toxicity. Further education and the use of a structured monitoring sheet may assist in more appropriate

  13. Analyzing the effect of routing protocols on media access control protocols in radio networks

    SciTech Connect

    Barrett, C. L.; Drozda, M.; Marathe, A.; Marathe, M. V.

    2002-01-01

    We study the effect of routing protocols on the performance of media access control (MAC) protocols in wireless radio networks. Three well known MAC protocols: 802.11, CSMA, and MACA are considered. Similarly three recently proposed routing protocols: AODV, DSR and LAR scheme 1 are considered. The experimental analysis was carried out using GloMoSim: a tool for simulating wireless networks. The main focus of our experiments was to study how the routing protocols affect the performance of the MAC protocols when the underlying network and traffic parameters are varied. The performance of the protocols was measured w.r.t. five important parameters: (i) number of received packets, (ii) average latency of each packet, (iii) throughput (iv) long term fairness and (v) number of control packets at the MAC layer level. Our results show that combinations of routing and MAC protocols yield varying performance under varying network topology and traffic situations. The result has an important implication; no combination of routing protocol and MAC protocol is the best over all situations. Also, the performance analysis of protocols at a given level in the protocol stack needs to be studied not locally in isolation but as a part of the complete protocol stack. A novel aspect of our work is the use of statistical technique, ANOVA (Analysis of Variance) to characterize the effect of routing protocols on MAC protocols. This technique is of independent interest and can be utilized in several other simulation and empirical studies.

  14. Report of the Ad Hoc Committee on Religious and Cultural Celebrations in the Library.

    ERIC Educational Resources Information Center

    Rathemacher, Andree; Grubman, Sheila Black; Lahiri, Amar; Gilton, Donna; Sharif, Mohammed

    The charge of the University of Rhode Island's Ad Hoc Committee on Religious and Cultural Celebrations in the Library was to: investigate all opportunities for the library to educate the campus community about religious and cultural holidays; consider all the major religions of the world and the possibility of having displays for the symbols of…

  15. The 5th Meeting of the Ad Hoc Panel on Terminal Configured Vehicles

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A report of the fifth meeting of the NASA Research and Technology Advisory Council, Ad Hoc panel on Terminal Configured Vehicles is presented. Some of the following topics were discussed; (1) microwave landing systems; (2) whole word computer system status; (3) flight path angle control: (4) VTOL approaches and landing technology; and (5) simulation study in wind shear.

  16. Using Dominating Sets to Improve the Performance of Mobile Ad Hoc Networks

    DTIC Science & Technology

    2005-09-01

    Communications Research Group (CCRG) directed by J.J., and students (Cintia, Nacho, Kumar and Venkatesh ) in Katia’s lab for their fellowship. I cannot...wireless conference, pages 156–162, 2002. [41] Katia Obraczka, Kumar Viswanath , and Gene Tsudik. Flooding for reliable multicast in multi-hop ad hoc

  17. Work, Family, and Community: Summary Proceedings of an Ad Hoc Committee.

    ERIC Educational Resources Information Center

    Hayes, Cheryl D., Ed.

    These proceedings contain summaries of five working group discussions and a discussion of suggestions for future research from an ad hoc meeting on Work, Family, and Community (Fedruary 21-22, 1980) in Washington, D.C. The meeting had these objectives: (1) to identify salient policy and research issues associated with changing patterns of labor…

  18. A Survey of Routing Protocols in Wireless Body Sensor Networks

    PubMed Central

    Bangash, Javed Iqbal; Abdullah, Abdul Hanan; Anisi, Mohammad Hossein; Khan, Abdul Waheed

    2014-01-01

    Wireless Body Sensor Networks (WBSNs) constitute a subset of Wireless Sensor Networks (WSNs) responsible for monitoring vital sign-related data of patients and accordingly route this data towards a sink. In routing sensed data towards sinks, WBSNs face some of the same routing challenges as general WSNs, but the unique requirements of WBSNs impose some more constraints that need to be addressed by the routing mechanisms. This paper identifies various issues and challenges in pursuit of effective routing in WBSNs. Furthermore, it provides a detailed literature review of the various existing routing protocols used in the WBSN domain by discussing their strengths and weaknesses. PMID:24419163

  19. Ad Hoc Supervision of General Practice Registrars as a "Community of Practice": Analysis, Interpretation and Re-Presentation

    ERIC Educational Resources Information Center

    Clement, T.; Brown, J.; Morrison, J.; Nestel, D.

    2016-01-01

    General practice registrars in Australia undertake most of their vocational training in accredited general practices. They typically see patients alone from the start of their community-based training and are expected to seek timely ad hoc support from their supervisor. Such ad hoc encounters are a mechanism for ensuring patient safety, but also…

  20. 76 FR 71308 - Codex Alimentarius Commission: Meeting of the Ad Hoc Intergovernmental Codex Task Force on Animal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Food Safety and Inspection Service Codex Alimentarius Commission: Meeting of the Ad Hoc... United States (U.S.) positions that will be discussed at the 6th Session of the Ad Hoc...

  1. Enhancements for distributed certificate authority approaches for mobile wireless ad hoc networks.

    SciTech Connect

    Van Leeuwen, Brian P.; Michalski, John T.; Anderson, William Erik

    2003-12-01

    Mobile wireless ad hoc networks that are resistant to adversarial manipulation are necessary for distributed systems used in military and security applications. Critical to the successful operation of these networks, which operate in the presence of adversarial stressors, are robust and efficient information assurance methods. In this report we describe necessary enhancements for a distributed certificate authority (CA) used in secure wireless network architectures. Necessary cryptographic algorithms used in distributed CAs are described and implementation enhancements of these algorithms in mobile wireless ad hoc networks are developed. The enhancements support a network's ability to detect compromised nodes and facilitate distributed CA services. We provide insights to the impacts the enhancements will have on network performance with timing diagrams and preliminary network simulation studies.

  2. Forming an ad-hoc nearby storage, based on IKAROS and social networking services

    NASA Astrophysics Data System (ADS)

    Filippidis, Christos; Cotronis, Yiannis; Markou, Christos

    2014-06-01

    We present an ad-hoc "nearby" storage, based on IKAROS and social networking services, such as Facebook. By design, IKAROS is capable to increase or decrease the number of nodes of the I/O system instance on the fly, without bringing everything down or losing data. IKAROS is capable to decide the file partition distribution schema, by taking on account requests from the user or an application, as well as a domain or a Virtual Organization policy. In this way, it is possible to form multiple instances of smaller capacity higher bandwidth storage utilities capable to respond in an ad-hoc manner. This approach, focusing on flexibility, can scale both up and down and so can provide more cost effective infrastructures for both large scale and smaller size systems. A set of experiments is performed comparing IKAROS with PVFS2 by using multiple clients requests under HPC IOR benchmark and MPICH2.

  3. Vehicular ad hoc network for a surveillance system using multifrequency band enhancement

    NASA Astrophysics Data System (ADS)

    Bunruangses, Montree; Sunat, Khamron; Mitatha, Somsak; Yupapin, Preecha P.

    2010-09-01

    We present a new design of a surveillance system via a vehicular ad hoc network (VANET) integrated by a 3-G or 4-G cellular wireless network. We propose dense wavelength division multiplexing wavelength enhancement for increasing the channel capacity and signal security. Increase in the number of channels can be obtained by increasing the wavelength density. Signal security is introduced by a specific wavelength filter controlled by the central operator. Optical communication wavelength enhancement is reviewed. The advantage of this proposed system is that it can easily be implemented and incorporated into the existing communication link in either a cellular or ad hoc wireless system, where signal security and hence privacy can be provided.

  4. An Ad-Hoc Adaptive Pilot Model for Pitch Axis Gross Acquisition Tasks

    NASA Technical Reports Server (NTRS)

    Hanson, Curtis E.

    2012-01-01

    An ad-hoc algorithm is presented for real-time adaptation of the well-known crossover pilot model and applied to pitch axis gross acquisition tasks in a generic fighter aircraft. Off-line tuning of the crossover model to human pilot data gathered in a fixed-based high fidelity simulation is first accomplished for a series of changes in aircraft dynamics to provide expected values for model parameters. It is shown that in most cases, for this application, the traditional crossover model can be reduced to a gain and a time delay. The ad-hoc adaptive pilot gain algorithm is shown to have desirable convergence properties for most types of changes in aircraft dynamics.

  5. An Adaptive QoS Routing Solution for MANET Based Multimedia Communications in Emergency Cases

    NASA Astrophysics Data System (ADS)

    Ramrekha, Tipu Arvind; Politis, Christos

    The Mobile Ad hoc Networks (MANET) is a wireless network deprived of any fixed central authoritative routing entity. It relies entirely on collaborating nodes forwarding packets from source to destination. This paper describes the design, implementation and performance evaluation of CHAMELEON, an adaptive Quality of Service (QoS) routing solution, with improved delay and jitter performances, enabling multimedia communication for MANETs in extreme emergency situations such as forest fire and terrorist attacks as defined in the PEACE project. CHAMELEON is designed to adapt its routing behaviour according to the size of a MANET. The reactive Ad Hoc on-Demand Distance Vector Routing (AODV) and proactive Optimized Link State Routing (OLSR) protocols are deemed appropriate for CHAMELEON through their performance evaluation in terms of delay and jitter for different MANET sizes in a building fire emergency scenario. CHAMELEON is then implemented in NS-2 and evaluated similarly. The paper concludes with a summary of findings so far and intended future work.

  6. EGPS: An Efficient Privacy Preserving Scheme for Vehicular ad hoc Networks

    NASA Astrophysics Data System (ADS)

    Zhao, Baokang; Su, Xiangyu; Su, Jinshu; Song, Ziming; Sun, Yipin; Tao, Jing; Tang, Yong; Chen, Shuhui; Zhao, Guohong; Chen, Yijiao

    2010-09-01

    In this paper, we propose EGPS, an efficient privacy preserving scheme for vehicular ad hoc networks. The EGPS scheme is based on a very efficient group signature and Identity Based Cryptography(IBC) techniques. Several security properties of EGPS, including the correctness and unforgeability have been proved. Furthermore, EGPS is also proved to be more efficient than GSIS, which is currently one of the best state-of-the-art VANET privacy preserving schemes.

  7. Ad Hoc Categories and False Memories: Memory Illusions for Categories Created On-the-Spot.

    PubMed

    Soro, Jerônimo C; Ferreira, Mário B; Semin, Gün R; Mata, André; Carneiro, Paula

    2017-04-06

    Three experiments were designed to test whether experimentally created ad hoc associative networks evoke false memories. We used the DRM (Deese, Roediger, McDermott) paradigm with lists of ad hoc categories composed of exemplars aggregated toward specific goals (e.g., going for a picnic) that do not share any consistent set of features. Experiment 1 revealed considerable levels of false recognitions of critical words from ad hoc categories. False recognitions occurred even when the lists were presented without an organizing theme (i.e., the category's label). Experiments 1 and 2 tested whether (a) the ease of identifying the categories' themes, and (b) the lists' backward associative strength could be driving the effect. List identifiability did not correlate with false recognition, and the effect remained even when backward associative strength was controlled for. Experiment 3 manipulated the distractor items in the recognition task to address the hypothesis that the salience of unrelated items could be facilitating the occurrence of the phenomenon. The effect remained when controlling for this source of facilitation. These results have implications for assumptions made by theories of false memories, namely the preexistence of associations in the activation-monitoring framework and the central role of gist extraction in fuzzy-trace theory, while providing evidence of the occurrence of false memories for more dynamic and context-dependent knowledge structures. (PsycINFO Database Record

  8. Real Time Semantic Interoperability in AD HOC Networks of Geospatial Data Sources: Challenges, Achievements and Perspectives

    NASA Astrophysics Data System (ADS)

    Mostafavi, M. A.; Bakillah, M.

    2012-07-01

    Recent advances in geospatial technologies have made available large amount of geospatial data. Meanwhile, new developments in Internet and communication technologies created a shift from isolated geospatial databases to ad hoc networks of geospatial data sources, where data sources can join or leave the network, and form groups to share data and services. However, effective integration and sharing of geospatial data among these data sources and their users are hampered by semantic heterogeneities. These heterogeneities affect the spatial, temporal and thematic aspects of geospatial concepts. There have been many efforts to address semantic interoperability issues in the geospatial domain. These efforts were mainly focused on resolving heterogeneities caused by different and implicit representations of the concepts. However, many approaches have focused on the thematic aspects, leaving aside the explicit representation of spatial and temporal aspects. Also, most semantic interoperability approaches for networks have focused on automating the semantic mapping process. However, the ad hoc network structure is continuously modified by source addition or removal, formation of groups, etc. This dynamic aspect is often neglected in those approaches. This paper proposes a conceptual framework for real time semantic interoperability in ad hoc networks of geospatial data sources. The conceptual framework presents the fundamental elements of real time semantic interoperability through a hierarchy of interrelated semantic states and processes. Then, we use the conceptual framework to set the discussion on the achievements that have already been made, the challenges that remain to be addressed and perspectives with respect to these challenges.

  9. Capacity-Delay Trade-Off in Collaborative Hybrid Ad-Hoc Networks with Coverage Sensing

    PubMed Central

    Chen, Lingyu; Luo, Wenbin; Liu, Chen; Hong, Xuemin; Shi, Jianghong

    2017-01-01

    The integration of ad hoc device-to-device (D2D) communications and open-access small cells can result in a networking paradigm called hybrid the ad hoc network, which is particularly promising in delivering delay-tolerant data. The capacity-delay performance of hybrid ad hoc networks has been studied extensively under a popular framework called scaling law analysis. These studies, however, do not take into account aspects of interference accumulation and queueing delay and, therefore, may lead to over-optimistic results. Moreover, focusing on the average measures, existing works fail to give finer-grained insights into the distribution of delays. This paper proposes an alternative analytical framework based on queueing theoretic models and physical interference models. We apply this framework to study the capacity-delay performance of a collaborative cellular D2D network with coverage sensing and two-hop relay. The new framework allows us to fully characterize the delay distribution in the transform domain and pinpoint the impacts of coverage sensing, user and base station densities, transmit power, user mobility and packet size on the capacity-delay trade-off. We show that under the condition of queueing equilibrium, the maximum throughput capacity per device saturates to an upper bound of 0.7239 λb/λu bits/s/Hz, where λb and λu are the densities of base stations and mobile users, respectively. PMID:28134769

  10. Ad hoc CubeSat constellations: Secondary launch coverage and distribution

    NASA Astrophysics Data System (ADS)

    Marinan, A.; Nicholas, A.; Cahoy, K.

    The primary purpose of a constellation is to obtain global measurements with improved spatial and temporal resolution. The small size, low cost, standardized form factor, and increasing availability of commercial parts for CubeSats make them ideal for use in constellations. However, without taking advantage of secondary payload opportunities, it would be costly to launch and distribute a CubeSat constellation into a specific configuration. A cost-effective way to launch a constellation of CubeSats is via consecutive secondary payload launch opportunities, but the resulting constellation would be an ad hoc mix of orbit parameters. We focus on the feasibility of cobbling together constellation-like functionality from multiple secondary payload opportunities. Each participating CubeSat (or set of CubeSats) per launch could have completely different orbital parameters, even without propulsion onboard the CubeSats or intermediate transfer carriers. We look at the ground coverages that could be obtained for a constellation of five to six orbital planes with one to six satellites in each plane. We analyze past and announced future launch opportunities for CubeSats, including launch platforms supported by the NASA Educational Launch of Nanosatellites (ELaNa). We consider combinations of possible launch locations and temporal spacings over the course of one year and simulate the resulting ground coverage patterns and revisit times for an ad hoc constellation using these launch opportunities. We perform this analysis for two separate case studies - one with only US launches and one with both US and non-US opportunities - and vary the number of satellites per orbital plane. Typical CubeSat mission lifetimes and deorbit times for low-altitude orbits are included in these analyses. The ad hoc constellation results are compared to coverage from uniformly-placed LEO constellations and are quantified in terms of revisit time, time to 100% global coverage, and response time. For mu

  11. SDL design of MPLS routing protocol in the private network

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Lu, Yang; Lin, Xiaokang

    2005-02-01

    Nowadays multi-protocol label switching (MPLS) technology has achieved great popularity in the world. Because MPLS adopts the scheme of "route once and switch many", routing is the key element to ensure packets are transmitted to destinations. Though there are many designs of MPLS routing protocol for public networks, they can hardly fit the private network very well for its special characteristics. This paper presents the design of MPLS routing protocol in the private network using the specification and description language (SDL), which is an object-oriented formal language and mainly used in communications area. In our design the whole autonomous system (AS) is regarded as a single area to reduce the number of protocol packets. The SDL module of MPLS routing protocol consists of four kinds of processes, namely Management, Checking, NeigSession and LSADbase. Simulations of the SDL design are run in many scenarios, the results of which indicate that the SDL module is manageable and the overall performance is satisfying. From our design and simulation experience, we find that the software development cycle can be drastically reduced by the use of SDL, and the code is easy to maintain and reuse.

  12. A Security Solution for IEEE 802.11's Ad-hoc Mode:Password-Authentication and Group Diffie-Hellman Key Exchange

    SciTech Connect

    Emmanuel, Bresson; Olivier, Chevassut; David, Pointcheval

    2005-10-01

    The IEEE 802 standards ease the deployment of networkinginfrastructures and enable employers to accesscorporate networks whiletraveling. These standards provide two modes of communication calledinfrastructure and ad-hoc modes. A security solution for the IEEE802.11's infrastructure mode took several years to reach maturity andfirmware are still been upgraded, yet a solution for the ad-hoc modeneeds to be specified. The present paper is a first attempt in thisdirection. It leverages the latest developments in the area ofpassword-based authentication and (group) Diffie-Hellman key exchange todevelop a provably-secure key-exchange protocol for IEEE 802.11's ad-hocmode. The protocol allows users to securely join and leave the wirelessgroup at time, accommodates either a single-shared password orpairwise-shared passwords among the group members, or at least with acentral server; achieves security against dictionary attacks in theideal-hash model (i.e. random-oracles). This is, to the best of ourknowledge, the first such protocol to appear in the cryptographicliterature.

  13. On-Demand Routing in Multi-hop Wireless Mobile Ad Hoc Networks

    DTIC Science & Technology

    2001-05-01

    6.1.1 Link Layer Emulation : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 68 6.1.2 Doppelganger Emulation...74 6.4 Implementing Doppelganger Emulation Via Direct Emulation : : : : : : : : : : : : : : : : 76 6.5 Validation of Direct Emulation...layers or filtering them out, depending on what the current emulated topology is. 6.1.2. Doppelganger Emulation Figure 6.5 depicts a network where

  14. Trust-Threshold Based Routing in Mobile Ad Hoc Delay Tolerant Networks

    DTIC Science & Technology

    2011-02-15

    indirect. X(£ + A£) I e-A"flt x rj(t), ifm*jand\\Ri\\=0 (4) if m * j and\\R{\\ > 0 The indirect trust evaluation toward nodej is given in Equation 4 above...node i knows that nodej is malicious when it is detected and a message is announced to the system, i.e.. when node/s place DCN (in Fig.l) is not zero

  15. 78 FR 8145 - Sequence 24 Findings of the EISA 436(h) Ad-Hoc Review Group on Green Building Certification Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-05

    ... ADMINISTRATION Sequence 24 Findings of the EISA 436(h) Ad-Hoc Review Group on Green Building Certification... partners in the EISA 436(h) Ad-Hoc Discussion Group are seeking public input regarding possible approaches... certification of green Federal buildings. GSA is using the deliberations from the EISA 436(h) Ad-hoc...

  16. Dynamic fair node spectrum allocation for ad hoc networks using random matrices

    NASA Astrophysics Data System (ADS)

    Rahmes, Mark; Lemieux, George; Chester, Dave; Sonnenberg, Jerry

    2015-05-01

    Dynamic Spectrum Access (DSA) is widely seen as a solution to the problem of limited spectrum, because of its ability to adapt the operating frequency of a radio. Mobile Ad Hoc Networks (MANETs) can extend high-capacity mobile communications over large areas where fixed and tethered-mobile systems are not available. In one use case with high potential impact, cognitive radio employs spectrum sensing to facilitate the identification of allocated frequencies not currently accessed by their primary users. Primary users own the rights to radiate at a specific frequency and geographic location, while secondary users opportunistically attempt to radiate at a specific frequency when the primary user is not using it. We populate a spatial radio environment map (REM) database with known information that can be leveraged in an ad hoc network to facilitate fair path use of the DSA-discovered links. Utilization of high-resolution geospatial data layers in RF propagation analysis is directly applicable. Random matrix theory (RMT) is useful in simulating network layer usage in nodes by a Wishart adjacency matrix. We use the Dijkstra algorithm for discovering ad hoc network node connection patterns. We present a method for analysts to dynamically allocate node-node path and link resources using fair division. User allocation of limited resources as a function of time must be dynamic and based on system fairness policies. The context of fair means that first available request for an asset is not envied as long as it is not yet allocated or tasked in order to prevent cycling of the system. This solution may also save money by offering a Pareto efficient repeatable process. We use a water fill queue algorithm to include Shapley value marginal contributions for allocation.

  17. A novel wavelength availability advertisement based ASON routing protocol implementation

    NASA Astrophysics Data System (ADS)

    Li, Jian; Liu, Juan; Zhang, Jie; Gu, Wanyi

    2005-11-01

    A novel wavelength availability advertisement based ASON routing protocol implementation is proposed in this paper which is derived from Open Shortest Path First protocol (OSPF) version 2. It can be applied to ASON network with a single control domain and can be easily extended to support routing in the multi-domain scenarios. Two new types of link state advertisement (LSA) are suggested for disseminating wavelength availability and network topology information. The OSPF mechanisms are inherited to ensure that the routing messages are delivered more reliably and converged more quickly while with fewer overheads. The topology auto discovery is realized through LSA flooding interacting with auto neighbor discovery using Link Management Protocol. The new LSA formats are given and how the link state database (LSD) is comprised is described. The new data structures proposed include topology resource list, adjacency list and route table. Then we analyze the differences of ASON in link state exchange, routing information flooding procedure, flushing procedure and new resources participating, i.e. new links or nodes join in an existing ASON. The link or node failure and recovery effect and how to deal with them are settled as well. In order to adopt different Routing and Wavelength Assignment (RWA) algorithms, a standard and efficient interface is designed. After extensive simulation we give the numerical analysis and come to the following conclusions: wavelength availability information flooding Convergence Time is about 30 milliseconds and it is not affected by RWA algorithms and the call traffic load; routing Protocol Average Overhead rises linearly with the increase of traffic load; Average Connection Setup Time decreases with the increase of traffic load because of the decrease of Average Routing Distance of the successfully lightpaths; Wavelength availability advertisement can greatly promote the blocking performance of ASON in relatively low traffic load; ASON

  18. A Network Coding Based Routing Protocol for Underwater Sensor Networks

    PubMed Central

    Wu, Huayang; Chen, Min; Guan, Xin

    2012-01-01

    Due to the particularities of the underwater environment, some negative factors will seriously interfere with data transmission rates, reliability of data communication, communication range, and network throughput and energy consumption of underwater sensor networks (UWSNs). Thus, full consideration of node energy savings, while maintaining a quick, correct and effective data transmission, extending the network life cycle are essential when routing protocols for underwater sensor networks are studied. In this paper, we have proposed a novel routing algorithm for UWSNs. To increase energy consumption efficiency and extend network lifetime, we propose a time-slot based routing algorithm (TSR).We designed a probability balanced mechanism and applied it to TSR. The theory of network coding is introduced to TSBR to meet the requirement of further reducing node energy consumption and extending network lifetime. Hence, time-slot based balanced network coding (TSBNC) comes into being. We evaluated the proposed time-slot based balancing routing algorithm and compared it with other classical underwater routing protocols. The simulation results show that the proposed protocol can reduce the probability of node conflicts, shorten the process of routing construction, balance energy consumption of each node and effectively prolong the network lifetime. PMID:22666045

  19. Smart border: ad-hoc wireless sensor networks for border surveillance

    NASA Astrophysics Data System (ADS)

    He, Jun; Fallahi, Mahmoud; Norwood, Robert A.; Peyghambarian, Nasser

    2011-06-01

    Wireless sensor networks have been proposed as promising candidates to provide automated monitoring, target tracking, and intrusion detection for border surveillance. In this paper, we demonstrate an ad-hoc wireless sensor network system for border surveillance. The network consists of heterogeneously autonomous sensor nodes that distributively cooperate with each other to enable a smart border in remote areas. This paper also presents energy-aware and sleeping algorithms designed to maximize the operating lifetime of the deployed sensor network. Lessons learned in building the network and important findings from field experiments are shared in the paper.

  20. Concept Detection and Using Concept in Ad-hoc of Microblog Search

    DTIC Science & Technology

    2012-11-01

    10,887,718 tweets with 200 tags and 2992055 tweets with 301 tags . We use character ASCII code to detect non-English tweets . In specifically, if a tweet ...hfang@ece.udel.edu Abstract: We report our system and experiments in TREC 2012 microblog Ad-hoc task. Our goal is to return most relevant tweets to...about 16 millions tweets over the period from Jan. 24th, 2011 to Feb. 8th, 2011. Each query is presented by short keywords and post time. Systems

  1. Panel Discussion : Report of the APS Ad-Hoc Committee on LGBT Issues

    NASA Astrophysics Data System (ADS)

    Atherton, Tim; Barthelemy, Ramon; Garmon, Savannah; Reeves, Kyle; APS Ad-Hoc Committee on LGBT Issues Team

    Following the presentation of the findings and recommendations of the APS Ad-Hoc Committee on LGBT Issues (C-LGBT) by Committee Chair Michael Falk, a panel discussion will be held featuring several members of the committee. The discussion will focus on how APS can best ensure the recommendations of the committee are carried out in a timely fashion and other ideas on future APS efforts toward LGBT inclusion in physics. Discussion topics will also include the research and other input that shaped the committee's findings and recommendations.

  2. Pheromone routing protocol on a scale-free network.

    PubMed

    Ling, Xiang; Hu, Mao-Bin; Jiang, Rui; Wang, Ruili; Cao, Xian-Bin; Wu, Qing-Song

    2009-12-01

    This paper proposes a routing strategy for network systems based on the local information of "pheromone." The overall traffic capacity of a network system can be evaluated by the critical packet generating rate R(c). Under this critical generating rate, the total packet number in the system first increases and then decreases to reach a balance state. The system behaves differently from that with a local routing strategy based on the node degree or shortest path routing strategy. Moreover, the pheromone routing strategy performs much better than the local routing strategy, which is demonstrated by a larger value of the critical generating rate. This protocol can be an alternation for superlarge networks, in which the global topology may not be available.

  3. A Security Analysis of the 802.11s Wireless Mesh Network Routing Protocol and Its Secure Routing Protocols

    PubMed Central

    Tan, Whye Kit; Lee, Sang-Gon; Lam, Jun Huy; Yoo, Seong-Moo

    2013-01-01

    Wireless mesh networks (WMNs) can act as a scalable backbone by connecting separate sensor networks and even by connecting WMNs to a wired network. The Hybrid Wireless Mesh Protocol (HWMP) is the default routing protocol for the 802.11s WMN. The routing protocol is one of the most important parts of the network, and it requires protection, especially in the wireless environment. The existing security protocols, such as the Broadcast Integrity Protocol (BIP), Counter with cipher block chaining message authentication code protocol (CCMP), Secure Hybrid Wireless Mesh Protocol (SHWMP), Identity Based Cryptography HWMP (IBC-HWMP), Elliptic Curve Digital Signature Algorithm HWMP (ECDSA-HWMP), and Watchdog-HWMP aim to protect the HWMP frames. In this paper, we have analyzed the vulnerabilities of the HWMP and developed security requirements to protect these identified vulnerabilities. We applied the security requirements to analyze the existing secure schemes for HWMP. The results of our analysis indicate that none of these protocols is able to satisfy all of the security requirements. We also present a quantitative complexity comparison among the protocols and an example of a security scheme for HWMP to demonstrate how the result of our research can be utilized. Our research results thus provide a tool for designing secure schemes for the HWMP. PMID:24002231

  4. A security analysis of the 802.11s wireless mesh network routing protocol and its secure routing protocols.

    PubMed

    Tan, Whye Kit; Lee, Sang-Gon; Lam, Jun Huy; Yoo, Seong-Moo

    2013-09-02

    Wireless mesh networks (WMNs) can act as a scalable backbone by connecting separate sensor networks and even by connecting WMNs to a wired network. The Hybrid Wireless Mesh Protocol (HWMP) is the default routing protocol for the 802.11s WMN. The routing protocol is one of the most important parts of the network, and it requires protection, especially in the wireless environment. The existing security protocols, such as the Broadcast Integrity Protocol (BIP), Counter with cipher block chaining message authentication code protocol (CCMP), Secure Hybrid Wireless Mesh Protocol (SHWMP), Identity Based Cryptography HWMP (IBC-HWMP), Elliptic Curve Digital Signature Algorithm HWMP (ECDSA-HWMP), and Watchdog-HWMP aim to protect the HWMP frames. In this paper, we have analyzed the vulnerabilities of the HWMP and developed security requirements to protect these identified vulnerabilities. We applied the security requirements to analyze the existing secure schemes for HWMP. The results of our analysis indicate that none of these protocols is able to satisfy all of the security requirements. We also present a quantitative complexity comparison among the protocols and an example of a security scheme for HWMP to demonstrate how the result of our research can be utilized. Our research results thus provide a tool for designing secure schemes for the HWMP.

  5. A Black Hole Attack Model for Reactive Ad-Hoc Protocols

    DTIC Science & Technology

    2012-03-01

    Technology Conference. IEEE, 2003. pp. 2286-2290. [BhS09] N. Bhalaji, and A. Shanmugam. "Association Between Nodes to Combat Blackhole Attack in DSR...2012. 102 [PSA09] A. Prathapani, L. Santhanam, and P. Agrawal. "Intelligent Honeypot Agent for Blackhole Attack Detection in Wireless Mesh

  6. JTP: An Energy-conscious Transport Protocol for Wireless Ad Hoc Networks

    DTIC Science & Technology

    2006-01-01

    notification (eten) for error-prone wireless and satellite networks,” Comput. Networks, vol. 46, no. 3, pp. 343–362, 2004. [19] D. Barman and I. Matta...Communication,” Wireless Networks, vol. 6, pp. 263–277, 2000. [24] D. Barman , I. Matta, E. Altman, and R. E. Azouzi, “TCP Optimization through FEC

  7. Reputation-Based Internet Protocol Security: A Multilayer Security Framework for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-09-01

    altitude aircraft, ships, high alti- tude aircraft, and satellite platforms . Each has different characteristics in mobility, available power, line-of...UAVs [3]. These two features often determine when a tactical UAV will be utilized. Tactical UAVs are lower in cost than larger platforms like...motivated research in behavior grading systems [56]. Peer-to-peer eCommerce appli- cations such as eBay, Amazon, uBid, and Yahoo have performed research that

  8. A Multihop Key Agreement Scheme for Wireless Ad Hoc Networks Based on Channel Characteristics

    PubMed Central

    Yu, Nenghai

    2013-01-01

    A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks. PMID:23766725

  9. Linking Satellites Via Earth "Hot Spots" and the Internet to Form Ad Hoc Constellations

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix; Lee, Richard Q.; Romanofsky, Robert; Zaman, Afoz; Popovic, Zoya

    2004-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet. the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in ad hoc constellations, mission autonomy and

  10. A multihop key agreement scheme for wireless ad hoc networks based on channel characteristics.

    PubMed

    Hao, Zhuo; Zhong, Sheng; Yu, Nenghai

    2013-01-01

    A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks.

  11. Analysis of a Rumor Routing Protocol with Limited Packet Lifetimes

    DTIC Science & Technology

    2010-03-01

    modified rumor routing protocol system................................................... 29 Figure 3: A MORRP node modeled in OPNET ...41 Table 4: Parameters for OPNET model verification simulations...packet-related parameters can be modeled by an arbitrary distribution. 2. Uses OPNET , a discrete-time network simulator, to analyze the effect each

  12. A Leasing Model to Deal with Partial Failures in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Gonzalez Boix, Elisa; van Cutsem, Tom; Vallejos, Jorge; de Meuter, Wolfgang; D'Hondt, Theo

    In mobile ad hoc networks (MANETs) many partial failures are the result of temporary network partitions due to the intermittent connectivity of mobile devices. Some of these failures will be permanent and require application-level failure handling. However, it is impossible to distinguish a permanent from a transient failure. Leasing provides a solution to this problem based on the temporal restriction of resources. But to date no leasing model has been designed specifically for MANETs. In this paper, we identify three characteristics required for a leasing model to be usable in a MANET, discuss the issues with existing leasing models and then propose the leased object references model, which integrates leasing with remote object references. In addition, we describe an implementation of the model in the programming language AmbientTalk. Leased object references provide an extensible framework that allows programmers to express their own leasing patterns and enables both lease holders (clients) and lease grantors (services) to deal with permanent failures.

  13. Energy conservation in ad hoc multimedia networks using traffic-shaping mechanisms

    NASA Astrophysics Data System (ADS)

    Chandra, Surendar

    2003-12-01

    In this work, we explore network traffic shaping mechanisms that deliver packets at pre-determined intervals; allowing the network interface to transition to a lower power consuming sleep state. We focus our efforts on commodity devices, IEEE 802.11b ad hoc mode and popular streaming formats. We argue that factors such as the lack of scheduling clock phase synchronization among the participants and scheduling delays introduced by back ground tasks affect the potential energy savings. Increasing the periodic transmission delays to transmit data infrequently can offset some of these effects at the expense of flooding the wireless channel for longer periods of time; potentially increasing the time to acquire the channel for non-multimedia traffic. Buffering mechanisms built into media browsers can mitigate the effects of these added delays from being mis-interpreted as network congestion. We show that practical implementations of such traffic shaping mechanisms can offer significant energy savings.

  14. A high performance, ad-hoc, fuzzy query processing system for relational databases

    NASA Technical Reports Server (NTRS)

    Mansfield, William H., Jr.; Fleischman, Robert M.

    1992-01-01

    Database queries involving imprecise or fuzzy predicates are currently an evolving area of academic and industrial research. Such queries place severe stress on the indexing and I/O subsystems of conventional database environments since they involve the search of large numbers of records. The Datacycle architecture and research prototype is a database environment that uses filtering technology to perform an efficient, exhaustive search of an entire database. It has recently been modified to include fuzzy predicates in its query processing. The approach obviates the need for complex index structures, provides unlimited query throughput, permits the use of ad-hoc fuzzy membership functions, and provides a deterministic response time largely independent of query complexity and load. This paper describes the Datacycle prototype implementation of fuzzy queries and some recent performance results.

  15. The improvement and simulation for LEACH clustering routing protocol

    NASA Astrophysics Data System (ADS)

    Ji, Ai-guo; Zhao, Jun-xiang

    2017-01-01

    An energy-balanced unequal multi-hop clustering routing protocol LEACH-EUMC is proposed in this paper. The candidate cluster head nodes are elected firstly, then they compete to be formal cluster head nodes by adding energy and distance factors, finally the date are transferred to sink through multi-hop. The results of simulation show that the improved algorithm is better than LEACH in network lifetime, energy consumption and the amount of data transmission.

  16. Reconfigurable Routing Protocol for Free Space Optical Sensor Networks

    PubMed Central

    Xie, Rong; Yang, Won-Hyuk; Kim, Young-Chon

    2012-01-01

    Recently, free space optical sensor networks (FSOSNs), which are based on free space optics (FSO) instead of radio frequency (RF), have gained increasing visibility over traditional wireless sensor networks (WSNs) due to their advantages such as larger capacity, higher security, and lower cost. However, the performance of FSOSNs is restricted to the requirement of a direct line-of-sight (LOS) path between a sender and a receiver pair. Once a node dies of energy depletion, the network would probably suffer from a dramatic decrease of connectivity, resulting in a huge loss of data packets. Thus, this paper proposes a reconfigurable routing protocol (RRP) to overcome this problem by dynamically reconfiguring the network virtual topology. The RRP works in three phases: (1) virtual topology construction, (2) routing establishment, and (3) reconfigurable routing. When data transmission begins, the data packets are first routed through the shortest hop paths. Then a reconfiguration is initiated by the node whose residual energy falls below a threshold. Nodes affected by this dying node are classified into two types, namely maintenance nodes and adjustment nodes, and they are reconfigured according to the types. An energy model is designed to evaluate the performance of RRP through OPNET simulation. Our simulation results indicate that the RRP achieves better performance compared with the simple-link protocol and a direct reconfiguration scheme in terms of connectivity, network lifetime, packet delivery ratio and the number of living nodes. PMID:22666061

  17. Reconfigurable routing protocol for free space optical sensor networks.

    PubMed

    Xie, Rong; Yang, Won-Hyuk; Kim, Young-Chon

    2012-01-01

    Recently, free space optical sensor networks (FSOSNs), which are based on free space optics (FSO) instead of radio frequency (RF), have gained increasing visibility over traditional wireless sensor networks (WSNs) due to their advantages such as larger capacity, higher security, and lower cost. However, the performance of FSOSNs is restricted to the requirement of a direct line-of-sight (LOS) path between a sender and a receiver pair. Once a node dies of energy depletion, the network would probably suffer from a dramatic decrease of connectivity, resulting in a huge loss of data packets. Thus, this paper proposes a reconfigurable routing protocol (RRP) to overcome this problem by dynamically reconfiguring the network virtual topology. The RRP works in three phases: (1) virtual topology construction, (2) routing establishment, and (3) reconfigurable routing. When data transmission begins, the data packets are first routed through the shortest hop paths. Then a reconfiguration is initiated by the node whose residual energy falls below a threshold. Nodes affected by this dying node are classified into two types, namely maintenance nodes and adjustment nodes, and they are reconfigured according to the types. An energy model is designed to evaluate the performance of RRP through OPNET simulation. Our simulation results indicate that the RRP achieves better performance compared with the simple-link protocol and a direct reconfiguration scheme in terms of connectivity, network lifetime, packet delivery ratio and the number of living nodes.

  18. A Secure Cluster-Based Multipath Routing Protocol for WMSNs

    PubMed Central

    Almalkawi, Islam T.; Zapata, Manel Guerrero; Al-Karaki, Jamal N.

    2011-01-01

    The new characteristics of Wireless Multimedia Sensor Network (WMSN) and its design issues brought by handling different traffic classes of multimedia content (video streams, audio, and still images) as well as scalar data over the network, make the proposed routing protocols for typical WSNs not directly applicable for WMSNs. Handling real-time multimedia data requires both energy efficiency and QoS assurance in order to ensure efficient utility of different capabilities of sensor resources and correct delivery of collected information. In this paper, we propose a Secure Cluster-based Multipath Routing protocol for WMSNs, SCMR, to satisfy the requirements of delivering different data types and support high data rate multimedia traffic. SCMR exploits the hierarchical structure of powerful cluster heads and the optimized multiple paths to support timeliness and reliable high data rate multimedia communication with minimum energy dissipation. Also, we present a light-weight distributed security mechanism of key management in order to secure the communication between sensor nodes and protect the network against different types of attacks. Performance evaluation from simulation results demonstrates a significant performance improvement comparing with existing protocols (which do not even provide any kind of security feature) in terms of average end-to-end delay, network throughput, packet delivery ratio, and energy consumption. PMID:22163854

  19. The Impact of Using Item Parcels on ad hoc Goodness of Fit Indices in Confirmatory Factor Analysis: An Empirical Example.

    ERIC Educational Resources Information Center

    Takahashi, Tomone; Nasser, Fadia

    The Arabic version of I. G. Sarason's (1984) Reactions to Tests scale was used to examine the impact of using item parcels on ad hoc goodness of fit indices in confirmatory factor analysis. Item parcels with different numbers of items and different numbers of parcels per factor were used. Analyses were conducted on a sample of 420 tenth graders…

  20. How Gas-dynamic Flare Models Powered by Petschek Reconnection Differ from Those with Ad Hoc Energy Sources

    NASA Astrophysics Data System (ADS)

    Longcope, D. W.; Klimchuk, J. A.

    2015-11-01

    Aspects of solar flare dynamics, such as chromospheric evaporation and flare light curves, have long been studied using one-dimensional models of plasma dynamics inside a static flare loop, subjected to some energy input. While extremely successful at explaining the observed characteristics of flares, all such models so far have specified energy input ad hoc, rather than deriving it self-consistently. There is broad consensus that flares are powered by magnetic energy released through reconnection. Recent work has generalized Petschek’s basic reconnection scenario, topological change followed by field line retraction and shock heating, to permit its inclusion in a one-dimensional flare loop model. Here we compare the gas dynamics driven by retraction and shocking to those from more conventional static loop models energized by ad hoc source terms. We find significant differences during the first minute, when retraction leads to larger kinetic energies and produces higher densities at the loop top, while ad hoc heating tends to rarify the loop top. The loop-top density concentration is related to the slow magnetosonic shock, characteristic of Petschek’s model, but persists beyond the retraction phase occurring in the outflow jet. This offers an explanation for observed loop-top sources of X-ray and EUV emission, with advantages over that provided by ad hoc heating scenarios. The cooling phases of the two models are, however, notably similar to one another, suggesting that observations at that stage will yield little information on the nature of energy input.

  1. The Role of Business in Education Reform: Blueprint for Action. Report of the Business Roundtable Ad Hoc Committee on Education.

    ERIC Educational Resources Information Center

    Business Roundtable, New York, NY.

    Because of the critical importance of education to the productivity and competitiveness of business, the Ad Hoc Committee on Education, comprised of senior executives from major corporations, was established in November 1987 to identify actions the Business Roundtable could take to improve the quality of elementary and secondary education in the…

  2. Sketching Awareness: A Participatory Study to Elicit Designs for Supporting Ad Hoc Emergency Medical Teamwork

    PubMed Central

    Kusunoki, Diana; Sarcevic, Aleksandra; Zhang, Zhan; Yala, Maria

    2014-01-01

    Prior CSCW research on awareness in clinical settings has mostly focused on higher-level team coordination spanning across longer-term trajectories at the department and inter-department levels. In this paper, we offer a perspective on what awareness means within the context of an ad hoc, time- and safety-critical medical setting by looking at teams treating severely ill patients with urgent needs. We report findings from four participatory design workshops conducted with emergency medicine clinicians at two regional emergency departments. Workshops were developed to elicit design ideas for information displays that support awareness in emergency medical situations. Through analysis of discussions and clinicians’ sketches of information displays, we identified five features of teamwork that can be used as a foundation for supporting awareness from the perspective of clinicians. Based on these findings, we contribute rich descriptions of four facets of awareness that teams manage during emergency medical situations: team member awareness, elapsed time awareness, teamwork-oriented and patient-driven task awareness, and overall progress awareness. We then discuss these four awareness types in relation to awareness facets found in the CSCW literature. PMID:25870498

  3. Ad Hoc Query Support For Very Large Simulation Mesh Data: The Metadata Approach

    SciTech Connect

    Lee, B; Snapp, R; Musick, R; Critchlow, T

    2001-12-17

    We present our approach to enabling approximate ad hoc queries on terabyte-scale mesh data generated from large scientific simulations through the extension and integration of database, statistical, and data mining techniques. There are several significant barriers to overcome in achieving this objective. First, large-scale simulation data is already at the multi-terabyte scale and growing quickly, thus rendering traditional forms of interactive data exploration and query processing untenable. Second, a priori knowledge of user queries is not available, making it impossible to tune special-purpose solutions. Third, the data has spatial and temporal aspects, as well as arbitrarily high dimensionality, which exacerbates the task of finding compact, accurate, and easy-to-compute data models. Our approach is to preprocess the mesh data to generate highly compressed, lossy models that are used in lieu of the original data to answer users' queries. This approach leads to interesting challenges. The model (equivalently, the content-oriented metadata) being generated must be smaller than the original data by at least an order of magnitude. Second, the metadata representation must contain enough information to support a broad class of queries. Finally, the accuracy and speed of the queries must be within the tolerances required by users. In this paper we give an overview of ongoing development efforts with an emphasis on extracting metadata and using it in query processing.

  4. Emergency Situation Prediction Mechanism: A Novel Approach for Intelligent Transportation System Using Vehicular Ad Hoc Networks.

    PubMed

    Ganeshkumar, P; Gokulakrishnan, P

    2015-01-01

    In Indian four-lane express highway, millions of vehicles are travelling every day. Accidents are unfortunate and frequently occurring in these highways causing deaths, increase in death toll, and damage to infrastructure. A mechanism is required to avoid such road accidents at the maximum to reduce the death toll. An Emergency Situation Prediction Mechanism, a novel and proactive approach, is proposed in this paper for achieving the best of Intelligent Transportation System using Vehicular Ad Hoc Network. ESPM intends to predict the possibility of occurrence of an accident in an Indian four-lane express highway. In ESPM, the emergency situation prediction is done by the Road Side Unit based on (i) the Status Report sent by the vehicles in the range of RSU and (ii) the road traffic flow analysis done by the RSU. Once the emergency situation or accident is predicted in advance, an Emergency Warning Message is constructed and disseminated to all vehicles in the area of RSU to alert and prevent the vehicles from accidents. ESPM performs well in emergency situation prediction in advance to the occurrence of an accident. ESPM predicts the emergency situation within 0.20 seconds which is comparatively less than the statistical value. The prediction accuracy of ESPM against vehicle density is found better in different traffic scenarios.

  5. A communication theoretical analysis of FRET-based mobile ad hoc molecular nanonetworks.

    PubMed

    Kuscu, Murat; Akan, Ozgur B

    2014-09-01

    Nanonetworks refer to a group of nanosized machines with very basic operational capabilities communicating to each other in order to accomplish more complex tasks such as in-body drug delivery, or chemical defense. Realizing reliable and high-rate communication between these nanomachines is a fundamental problem for the practicality of these nanonetworks. Recently, we have proposed a molecular communication method based on Förster Resonance Energy Transfer (FRET) which is a nonradiative excited state energy transfer phenomenon observed among fluorescent molecules, i.e., fluorophores. We have modeled the FRET-based communication channel considering the fluorophores as single-molecular immobile nanomachines, and shown its reliability at high rates, and practicality at the current stage of nanotechnology. In this study, for the first time in the literature, we investigate the network of mobile nanomachines communicating through FRET. We introduce two novel mobile molecular nanonetworks: FRET-based mobile molecular sensor/actor nanonetwork (FRET-MSAN) which is a distributed system of mobile fluorophores acting as sensor or actor node; and FRET-based mobile ad hoc molecular nanonetwork (FRET-MAMNET) which consists of fluorophore-based nanotransmitter, nanoreceivers and nanorelays. We model the single message propagation based on birth-death processes with continuous time Markov chains. We evaluate the performance of FRET-MSAN and FRET-MAMNET in terms of successful transmission probability and mean extinction time of the messages, system throughput, channel capacity and achievable communication rates.

  6. Report of the APS Ad-Hoc Committee on LGBT Issues - Presentation of Findings and Recommendations

    NASA Astrophysics Data System (ADS)

    Falk, Michael

    In 2014 the Executive Officer of the American Physical Society (APS), Kate Kirby, created an Ad-Hoc Committee on LGBT Issues (C-LGBT) charged with reporting on the obstacles to inclusion of LGBT physicists, a term which for the purpose of this report refers to persons who self-identify as lesbian, gay, bisexual, transgender, queer, questioning, intersex, or asexual, as well as other sexual and gender minorities. The full charge was as follows: ``The committee will advise the APS on the current status of LGBT issues in physics, provide recommendations for greater inclusion, and engage physicists in laying the foundation for a more inclusive physics community. ?More specifically, the committee will investigate LGBT representation in physics, assess the educational and professional climate in physics, recommend changes in policies and practices that impact LGBT physicists, and address other issues that affect inclusion.'' We will present the findings and recommendations of the C-LGBT final report, and a panel discussion will be held following the presentation to discuss the future of APS efforts toward LGBT inclusion in physics.

  7. Report of the APS Ad-Hoc Committee on LGBT Issues - Presentation of Findings and Recommendations

    NASA Astrophysics Data System (ADS)

    Long, Elena

    2016-03-01

    In 2014 the Executive Officer of the American Physical Society (APS), Kate Kirby, created an Ad-Hoc Committee on LGBT Issues (C-LGBT) charged with reporting on the obstacles to inclusion of LGBT physicists, a term which for the purpose of this report refers to persons who self-identify as lesbian, gay, bisexual, transgender, queer, questioning, intersex, or asexual, as well as other sexual and gender minorities. The full charge was as follows: ``The committee will advise the APS on the current status of LGBT issues in physics, provide recommendations for greater inclusion, and engage physicists in laying the foundation for a more inclusive physics community? More specifically, the committee will investigate LGBT representation in physics, assess the educational and professional climate in physics, recommend changes in policies and practices that impact LGBT physicists, and address other issues that affect inclusion.'' We will present the findings and recommendations of the C-LGBT final report, and a panel discussion will be held following the presentation to discuss the future of APS efforts toward LGBT inclusion in physics.

  8. A DNA-Inspired Encryption Methodology for Secure, Mobile Ad Hoc Networks

    NASA Technical Reports Server (NTRS)

    Shaw, Harry

    2012-01-01

    Users are pushing for greater physical mobility with their network and Internet access. Mobile ad hoc networks (MANET) can provide an efficient mobile network architecture, but security is a key concern. A figure summarizes differences in the state of network security for MANET and fixed networks. MANETs require the ability to distinguish trusted peers, and tolerate the ingress/egress of nodes on an unscheduled basis. Because the networks by their very nature are mobile and self-organizing, use of a Public Key Infra structure (PKI), X.509 certificates, RSA, and nonce ex changes becomes problematic if the ideal of MANET is to be achieved. Molecular biology models such as DNA evolution can provide a basis for a proprietary security architecture that achieves high degrees of diffusion and confusion, and resistance to cryptanalysis. A proprietary encryption mechanism was developed that uses the principles of DNA replication and steganography (hidden word cryptography) for confidentiality and authentication. The foundation of the approach includes organization of coded words and messages using base pairs organized into genes, an expandable genome consisting of DNA-based chromosome keys, and a DNA-based message encoding, replication, and evolution and fitness. In evolutionary computing, a fitness algorithm determines whether candidate solutions, in this case encrypted messages, are sufficiently encrypted to be transmitted. The technology provides a mechanism for confidential electronic traffic over a MANET without a PKI for authenticating users.

  9. Standardization of Negative Controls in Diagnostic Immunohistochemistry: Recommendations From the International Ad Hoc Expert Panel

    PubMed Central

    Torlakovic, Emina E.; Francis, Glenn; Garratt, John; Gilks, Blake; Hyjek, Elizabeth; Ibrahim, Merdol; Miller, Rodney; Nielsen, Søren; Petcu, Eugen B.; Swanson, Paul E.; Taylor, Clive R.; Vyberg, Mogens

    2014-01-01

    Standardization of controls, both positive and negative controls, is needed for diagnostic immunohistochemistry (dIHC). The use of IHC-negative controls, irrespective of type, although well established, is not standardized. As such, the relevance and applicability of negative controls continues to challenge both pathologists and laboratory budgets. Despite the clear theoretical notion that appropriate controls serve to demonstrate the sensitivity and specificity of the dIHC test, it remains unclear which types of positive and negative controls are applicable and/or useful in day-to-day clinical practice. There is a perceived need to provide “best practice recommendations” for the use of negative controls. This perception is driven not only by logistics and cost issues, but also by increased pressure for accurate IHC testing, especially when IHC is performed for predictive markers, the number of which is rising as personalized medicine continues to develop. Herein, an international ad hoc expert panel reviews classification of negative controls relevant to clinical practice, proposes standard terminology for negative controls, considers the total evidence of IHC specificity that is available to pathologists, and develops a set of recommendations for the use of negative controls in dIHC based on “fit-for-use” principles. PMID:24714041

  10. A commentary on the disparate perspectives of clinical microbiologists and surgeons: ad hoc antimicrobial use.

    PubMed

    O'Connell, Nuala H; O'Connor, Ciara; O'Mahony, Jim; Lobo, Ronstan; Hayes, Maria; Masterson, Eric; Larvin, Michael; Coffey, J Calvin; Dunne, Colum

    2014-01-01

    Prosthetic joints and other orthopedic implants have improved quality of life for patients world-wide and the use of such devices is increasing. However, while infection rates subsequent to associated surgery are relatively low (<3%), the consequences of incidence are considerable, encompassing morbidity (including amputation) and mortality in addition to significant social and economic costs. Emphasis, therefore, has been placed on mitigating microbial risk, with clinical microbiologists and surgeons utilizing rapidly evolving molecular laboratory techniques in detection and diagnosis of infection, which still occurs despite sophisticated patient management. Multidisciplinary approaches are regularly adopted to achieve this. In this commentary, we describe an unusual case of Actinomyces infection in total hip arthroplasty and, in that context, describe the perspectives of the clinical microbiology and surgical teams and how they contrasted. More specifically, this case demonstrates an ad hoc approach to structured eradication of biofilms and intracellular bacteria related to biomaterials, as reflected in early usage of linezolid. This is a complex topic and, as described in this case, such accelerated treatment can be effective. This commentary focuses on the merits of such inadvisable use of potent antimicrobials amid the risk of diminishing valuable antimicrobial efficacy, albeit resulting in desirable patient outcomes.

  11. Linking satellites via Earth hot spots and the Internet to form ad hoc constellations

    NASA Astrophysics Data System (ADS)

    Mandl, Daniel; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix A.; Lee, Richard Q.; Romanofsky, Robert R.; Zaman, Afroz; Popovic, Zoya; Sherwood, Robert L.; Chien, Steve; Davies, Ashley

    2005-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet, the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in the area of adaptive antenna arrays and some of the related successful autonomy software that has been implemented using EO-1 and other operational satellites.

  12. Integration of Body Sensor Networks and Vehicular Ad-hoc Networks for Traffic Safety.

    PubMed

    Reyes-Muñoz, Angelica; Domingo, Mari Carmen; López-Trinidad, Marco Antonio; Delgado, José Luis

    2016-01-15

    The emergence of Body Sensor Networks (BSNs) constitutes a new and fast growing trend for the development of daily routine applications. However, in the case of heterogeneous BSNs integration with Vehicular ad hoc Networks (VANETs) a large number of difficulties remain, that must be solved, especially when talking about the detection of human state factors that impair the driving of motor vehicles. The main contributions of this investigation are principally three: (1) an exhaustive review of the current mechanisms to detect four basic physiological behavior states (drowsy, drunk, driving under emotional state disorders and distracted driving) that may cause traffic accidents is presented; (2) A middleware architecture is proposed. This architecture can communicate with the car dashboard, emergency services, vehicles belonging to the VANET and road or street facilities. This architecture seeks on the one hand to improve the car driving experience of the driver and on the other hand to extend security mechanisms for the surrounding individuals; and (3) as a proof of concept, an Android real-time attention low level detection application that runs in a next-generation smartphone is developed. The application features mechanisms that allow one to measure the degree of attention of a driver on the base of her/his EEG signals, establish wireless communication links via various standard wireless means, GPRS, Bluetooth and WiFi and issue alarms of critical low driver attention levels.

  13. Adaptive Control Parameters for Dispersal of Multi-Agent Mobile Ad Hoc Network (MANET) Swarms

    SciTech Connect

    Kurt Derr; Milos Manic

    2013-11-01

    A mobile ad hoc network is a collection of independent nodes that communicate wirelessly with one another. This paper investigates nodes that are swarm robots with communications and sensing capabilities. Each robot in the swarm may operate in a distributed and decentralized manner to achieve some goal. This paper presents a novel approach to dynamically adapting control parameters to achieve mesh configuration stability. The presented approach to robot interaction is based on spring force laws (attraction and repulsion laws) to create near-optimal mesh like configurations. In prior work, we presented the extended virtual spring mesh (EVSM) algorithm for the dispersion of robot swarms. This paper extends the EVSM framework by providing the first known study on the effects of adaptive versus static control parameters on robot swarm stability. The EVSM algorithm provides the following novelties: 1) improved performance with adaptive control parameters and 2) accelerated convergence with high formation effectiveness. Simulation results show that 120 robots reach convergence using adaptive control parameters more than twice as fast as with static control parameters in a multiple obstacle environment.

  14. The congestion control algorithm based on queue management of each node in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Wei, Yifei; Chang, Lin; Wang, Yali; Wang, Gaoping

    2016-12-01

    This paper proposes an active queue management mechanism, considering the node's own ability and its importance in the network to set the queue threshold. As the network load increases, local congestion of mobile ad hoc network may lead to network performance degradation, hot node's energy consumption increase even failure. If small energy nodes congested because of forwarding data packets, then when it is used as the source node will cause a lot of packet loss. This paper proposes an active queue management mechanism, considering the node's own ability and its importance in the network to set the queue threshold. Controlling nodes buffer queue in different levels of congestion area probability by adjusting the upper limits and lower limits, thus nodes can adjust responsibility of forwarding data packets according to their own situation. The proposed algorithm will slow down the send rate hop by hop along the data package transmission direction from congestion node to source node so that to prevent further congestion from the source node. The simulation results show that, the algorithm can better play the data forwarding ability of strong nodes, protect the weak nodes, can effectively alleviate the network congestion situation.

  15. Standardization of negative controls in diagnostic immunohistochemistry: recommendations from the international ad hoc expert panel.

    PubMed

    Torlakovic, Emina E; Francis, Glenn; Garratt, John; Gilks, Blake; Hyjek, Elizabeth; Ibrahim, Merdol; Miller, Rodney; Nielsen, Søren; Petcu, Eugen B; Swanson, Paul E; Taylor, Clive R; Vyberg, Mogens

    2014-04-01

    Standardization of controls, both positive and negative controls, is needed for diagnostic immunohistochemistry (dIHC). The use of IHC-negative controls, irrespective of type, although well established, is not standardized. As such, the relevance and applicability of negative controls continues to challenge both pathologists and laboratory budgets. Despite the clear theoretical notion that appropriate controls serve to demonstrate the sensitivity and specificity of the dIHC test, it remains unclear which types of positive and negative controls are applicable and/or useful in day-to-day clinical practice. There is a perceived need to provide "best practice recommendations" for the use of negative controls. This perception is driven not only by logistics and cost issues, but also by increased pressure for accurate IHC testing, especially when IHC is performed for predictive markers, the number of which is rising as personalized medicine continues to develop. Herein, an international ad hoc expert panel reviews classification of negative controls relevant to clinical practice, proposes standard terminology for negative controls, considers the total evidence of IHC specificity that is available to pathologists, and develops a set of recommendations for the use of negative controls in dIHC based on "fit-for-use" principles.

  16. Integrated data lookup and replication scheme in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Chen, Kai; Nahrstedt, Klara

    2001-11-01

    Accessing remote data is a challenging task in mobile ad hoc networks. Two problems have to be solved: (1) how to learn about available data in the network; and (2) how to access desired data even when the original copy of the data is unreachable. In this paper, we develop an integrated data lookup and replication scheme to solve these problems. In our scheme, a group of mobile nodes collectively host a set of data to improve data accessibility for all members of the group. They exchange data availability information by broadcasting advertising (ad) messages to the group using an adaptive sending rate policy. The ad messages are used by other nodes to derive a local data lookup table, and to reduce data redundancy within a connected group. Our data replication scheme predicts group partitioning based on each node's current location and movement patterns, and replicates data to other partitions before partitioning occurs. Our simulations show that data availability information can quickly propagate throughout the network, and that the successful data access ratio of each node is significantly improved.

  17. Emergency Situation Prediction Mechanism: A Novel Approach for Intelligent Transportation System Using Vehicular Ad Hoc Networks

    PubMed Central

    Gokulakrishnan, P.

    2015-01-01

    In Indian four-lane express highway, millions of vehicles are travelling every day. Accidents are unfortunate and frequently occurring in these highways causing deaths, increase in death toll, and damage to infrastructure. A mechanism is required to avoid such road accidents at the maximum to reduce the death toll. An Emergency Situation Prediction Mechanism, a novel and proactive approach, is proposed in this paper for achieving the best of Intelligent Transportation System using Vehicular Ad Hoc Network. ESPM intends to predict the possibility of occurrence of an accident in an Indian four-lane express highway. In ESPM, the emergency situation prediction is done by the Road Side Unit based on (i) the Status Report sent by the vehicles in the range of RSU and (ii) the road traffic flow analysis done by the RSU. Once the emergency situation or accident is predicted in advance, an Emergency Warning Message is constructed and disseminated to all vehicles in the area of RSU to alert and prevent the vehicles from accidents. ESPM performs well in emergency situation prediction in advance to the occurrence of an accident. ESPM predicts the emergency situation within 0.20 seconds which is comparatively less than the statistical value. The prediction accuracy of ESPM against vehicle density is found better in different traffic scenarios. PMID:26065014

  18. Road Accident Prevention with Instant Emergency Warning Message Dissemination in Vehicular Ad-Hoc Network.

    PubMed

    Gokulakrishnan, P; Ganeshkumar, P

    2015-01-01

    A Road Accident Prevention (RAP) scheme based on Vehicular Backbone Network (VBN) structure is proposed in this paper for Vehicular Ad-hoc Network (VANET). The RAP scheme attempts to prevent vehicles from highway road traffic accidents and thereby reduces death and injury rates. Once the possibility of an emergency situation (i.e. an accident) is predicted in advance, instantly RAP initiates a highway road traffic accident prevention scheme. The RAP scheme constitutes the following activities: (i) the Road Side Unit (RSU) constructs a Prediction Report (PR) based on the status of the vehicles and traffic in the highway roads, (ii) the RSU generates an Emergency Warning Message (EWM) based on an abnormal PR, (iii) the RSU forms a VBN structure and (iv) the RSU disseminates the EWM to the vehicles that holds the high Risk Factor (RF) and travels in High Risk Zone (HRZ). These vehicles might reside either within the RSU's coverage area or outside RSU's coverage area (reached using VBN structure). The RAP scheme improves the performance of EWM dissemination in terms of increase in notification and decrease in end-to-end delay. The RAP scheme also reduces infrastructure cost (number of RSUs) by formulating and deploying the VBN structure. The RAP scheme with VBN structure improves notification by 19 percent and end-to-end delay by 14.38 percent for a vehicle density of 160 vehicles. It is also proved from the simulation experiment that the performance of RAP scheme is promising in 4-lane highway roads.

  19. Integration of Body Sensor Networks and Vehicular Ad-hoc Networks for Traffic Safety

    PubMed Central

    Reyes-Muñoz, Angelica; Domingo, Mari Carmen; López-Trinidad, Marco Antonio; Delgado, José Luis

    2016-01-01

    The emergence of Body Sensor Networks (BSNs) constitutes a new and fast growing trend for the development of daily routine applications. However, in the case of heterogeneous BSNs integration with Vehicular ad hoc Networks (VANETs) a large number of difficulties remain, that must be solved, especially when talking about the detection of human state factors that impair the driving of motor vehicles. The main contributions of this investigation are principally three: (1) an exhaustive review of the current mechanisms to detect four basic physiological behavior states (drowsy, drunk, driving under emotional state disorders and distracted driving) that may cause traffic accidents is presented; (2) A middleware architecture is proposed. This architecture can communicate with the car dashboard, emergency services, vehicles belonging to the VANET and road or street facilities. This architecture seeks on the one hand to improve the car driving experience of the driver and on the other hand to extend security mechanisms for the surrounding individuals; and (3) as a proof of concept, an Android real-time attention low level detection application that runs in a next-generation smartphone is developed. The application features mechanisms that allow one to measure the degree of attention of a driver on the base of her/his EEG signals, establish wireless communication links via various standard wireless means, GPRS, Bluetooth and WiFi and issue alarms of critical low driver attention levels. PMID:26784204

  20. Securing Mobile Ad Hoc Networks Using Danger Theory-Based Artificial Immune Algorithm

    PubMed Central

    2015-01-01

    A mobile ad hoc network (MANET) is a set of mobile, decentralized, and self-organizing nodes that are used in special cases, such as in the military. MANET properties render the environment of this network vulnerable to different types of attacks, including black hole, wormhole and flooding-based attacks. Flooding-based attacks are one of the most dangerous attacks that aim to consume all network resources and thus paralyze the functionality of the whole network. Therefore, the objective of this paper is to investigate the capability of a danger theory-based artificial immune algorithm called the mobile dendritic cell algorithm (MDCA) to detect flooding-based attacks in MANETs. The MDCA applies the dendritic cell algorithm (DCA) to secure the MANET with additional improvements. The MDCA is tested and validated using Qualnet v7.1 simulation tool. This work also introduces a new simulation module for a flooding attack called the resource consumption attack (RCA) using Qualnet v7.1. The results highlight the high efficiency of the MDCA in detecting RCAs in MANETs. PMID:25946001

  1. Ad Hoc modeling, expert problem solving, and R&T program evaluation

    NASA Technical Reports Server (NTRS)

    Silverman, B. G.; Liebowitz, J.; Moustakis, V. S.

    1983-01-01

    A simplified cost and time (SCAT) analysis program utilizing personal-computer technology is presented and demonstrated in the case of the NASA-Goddard end-to-end data system. The difficulties encountered in implementing complex program-selection and evaluation models in the research and technology field are outlined. The prototype SCAT system described here is designed to allow user-friendly ad hoc modeling in real time and at low cost. A worksheet constructed on the computer screen displays the critical parameters and shows how each is affected when one is altered experimentally. In the NASA case, satellite data-output and control requirements, ground-facility data-handling capabilities, and project priorities are intricately interrelated. Scenario studies of the effects of spacecraft phaseout or new spacecraft on throughput and delay parameters are shown. The use of a network of personal computers for higher-level coordination of decision-making processes is suggested, as a complement or alternative to complex large-scale modeling.

  2. A Sensitive Secondary Users Selection Algorithm for Cognitive Radio Ad Hoc Networks

    PubMed Central

    Li, Aohan; Han, Guangjie; Wan, Liangtian; Shu, Lei

    2016-01-01

    Secondary Users (SUs) are allowed to use the temporarily unused licensed spectrum without disturbing Primary Users (PUs) in Cognitive Radio Ad Hoc Networks (CRAHNs). Existing architectures for CRAHNs impose energy-consuming Cognitive Radios (CRs) on SUs. However, the advanced CRs will increase energy cost for their cognitive functionalities, which is undesirable for the battery powered devices. A new architecture referred to as spectral Requirement-based CRAHN (RCRAHN) is proposed to enhance energy efficiency for CRAHNs in this paper. In RCRAHNs, only parts of SUs are equipped with CRs. SUs equipped with CRs are referred to as Cognitive Radio Users (CRUs). To further enhance energy efficiency of CRAHNs, we aim to select minimum CRUs to sense available spectrum. A non-linear programming problem is mathematically formulated under the constraints of energy efficiency and real-time. Considering the NP-hardness of the problem, a framework of a heuristic algorithm referred to as Sensitive Secondary Users Selection (SSUS) was designed to compute the near-optimal solutions. The simulation results demonstrate that SSUS not only improves the energy efficiency, but also achieves satisfied performances in end-to-end delay and communication reliability. PMID:27023562

  3. An adaptive neural swarm approach for intrusion defense in ad hoc networks

    NASA Astrophysics Data System (ADS)

    Cannady, James

    2011-06-01

    Wireless sensor networks (WSN) and mobile ad hoc networks (MANET) are being increasingly deployed in critical applications due to the flexibility and extensibility of the technology. While these networks possess numerous advantages over traditional wireless systems in dynamic environments they are still vulnerable to many of the same types of host-based and distributed attacks common to those systems. Unfortunately, the limited power and bandwidth available in WSNs and MANETs, combined with the dynamic connectivity that is a defining characteristic of the technology, makes it extremely difficult to utilize traditional intrusion detection techniques. This paper describes an approach to accurately and efficiently detect potentially damaging activity in WSNs and MANETs. It enables the network as a whole to recognize attacks, anomalies, and potential vulnerabilities in a distributive manner that reflects the autonomic processes of biological systems. Each component of the network recognizes activity in its local environment and then contributes to the overall situational awareness of the entire system. The approach utilizes agent-based swarm intelligence to adaptively identify potential data sources on each node and on adjacent nodes throughout the network. The swarm agents then self-organize into modular neural networks that utilize a reinforcement learning algorithm to identify relevant behavior patterns in the data without supervision. Once the modular neural networks have established interconnectivity both locally and with neighboring nodes the analysis of events within the network can be conducted collectively in real-time. The approach has been shown to be extremely effective in identifying distributed network attacks.

  4. Zone-Based Routing Protocol for Wireless Sensor Networks

    PubMed Central

    Venkateswarlu Kumaramangalam, Muni; Adiyapatham, Kandasamy; Kandasamy, Chandrasekaran

    2014-01-01

    Extensive research happening across the globe witnessed the importance of Wireless Sensor Network in the present day application world. In the recent past, various routing algorithms have been proposed to elevate WSN network lifetime. Clustering mechanism is highly successful in conserving energy resources for network activities and has become promising field for researches. However, the problem of unbalanced energy consumption is still open because the cluster head activities are tightly coupled with role and location of a particular node in the network. Several unequal clustering algorithms are proposed to solve this wireless sensor network multihop hot spot problem. Current unequal clustering mechanisms consider only intra- and intercluster communication cost. Proper organization of wireless sensor network into clusters enables efficient utilization of limited resources and enhances lifetime of deployed sensor nodes. This paper considers a novel network organization scheme, energy-efficient edge-based network partitioning scheme, to organize sensor nodes into clusters of equal size. Also, it proposes a cluster-based routing algorithm, called zone-based routing protocol (ZBRP), for elevating sensor network lifetime. Experimental results show that ZBRP out-performs interims of network lifetime and energy conservation with its uniform energy consumption among the cluster heads. PMID:27437455

  5. Bringing Ad-Hoc Analytics to Big Earth Data: the EarthServer Experience

    NASA Astrophysics Data System (ADS)

    Baumann, Peter

    2014-05-01

    From the commonly accepted Vs defining the Big Data challenge - volume, velocity, variety - we more and more learn that the sheer volume is not the only, and often not even the decisive factor inhibiting access and analytics. In particular variety of data is a frequent core issue, posing manifold issues. Based on this observation we claim that a key aspect to analytics is the freedom to ask any questions, simple or complex, anytime and combining any choice of data structures, whatever diverging they may be. Actually, techniques for such "ad-hoc queries" we can learn from classical databases. Their concept of high-level query languages brings along several benefits: a uniform semantic, allowing machine-to-machine communication, including automatic generation of queries; massive server-side optimization and parallelization; and building attractive client interfaces hiding the query syntax from casual users while allowing power users to utilize it. However, these benefits used to be available only on tabular and set oriented data, text, and - more recently - graph data. With the advent of Array Databases, they become available on large multidimensional raster data assets as well, getting one step closer to the Holy Grail of itnegrated, uniform retrieval for users. ErthServer is a transatlantic initiative setting up operationa linfrastructures based on this paradigm. In our talk, we present core EarthServer technology concepts as well as a spectrum of Earth Science applications utilizing the EarthServer platform for versatile, visualisation supported analytics services. Further, we discuss the substantial impact EarthServer is having on Big Geo Data standardization in OGC and ISO. Time and Internet connection permitting a live demo can be presented.

  6. Exploring the Role of Ad Hoc Grassroots Organizations Providing Humanitarian Aid on Lesvos, Greece

    PubMed Central

    Kitching, George Tjensvoll; J. Haavik, Hanne; Tandstad, Birgit J.; Zaman, Muhammad; Darj, Elisabeth

    2016-01-01

    Introduction: Syrian refugees displaced into Turkey have attempted high-risk sea migrations to reach safer destinations in Europe, most often initially arriving on the Greek island of Lesvos. These refugees were often in need of basic humanitarian assistance that has been provided in part by a new category of ad hoc grassroots organizations (AHGOs). The aim of this study was to understand the internal and external operations of these AHGOs and their role on Lesvos. Methods: The experiences of AHGOs were investigated through a qualitative research design utilizing semi-structured interviews with organization leaders and spokespersons. AHGOs identified through media and social media sources as new Lesvos-specific organizations were purposively invited to complete an interview over phone, Skype or email. Data analysis of the transcribed interviews was performed by Systematic Text Condensation. Results: Forty-one organizations were contacted and 13 interviews were conducted. Most organizations were formed in autumn 2015 responding to the greater influx of refugees and migrants at that time and reported an absence of professional humanitarian agencies providing aid on Lesvos. Three categories emerged from the material. Features of organizations; Features of volunteers and; Evolution of AHGOs. The organizations perceived themselves capable of evaluating needs, mobilizing resources, funding and providing quick response. The volunteers came with limited humanitarian experience and from a wide variety of nationalities and professional backgrounds, and the organizations developed while on Lesvos. Discussion: Knowledge from our findings of AHGOs response to this complex disaster on Lesvos could be utilized in future catastrophes. We conclude that AHGOs may prove effective at providing humanitarian aid in a surge response when international non-governmental organizations are unable to respond quickly. In future complex disasters AHGOs should be recognized as new humanitarian

  7. Road Accident Prevention with Instant Emergency Warning Message Dissemination in Vehicular Ad-Hoc Network

    PubMed Central

    P, Gokulakrishnan; P, Ganeshkumar

    2015-01-01

    A Road Accident Prevention (RAP) scheme based on Vehicular Backbone Network (VBN) structure is proposed in this paper for Vehicular Ad-hoc Network (VANET). The RAP scheme attempts to prevent vehicles from highway road traffic accidents and thereby reduces death and injury rates. Once the possibility of an emergency situation (i.e. an accident) is predicted in advance, instantly RAP initiates a highway road traffic accident prevention scheme. The RAP scheme constitutes the following activities: (i) the Road Side Unit (RSU) constructs a Prediction Report (PR) based on the status of the vehicles and traffic in the highway roads, (ii) the RSU generates an Emergency Warning Message (EWM) based on an abnormal PR, (iii) the RSU forms a VBN structure and (iv) the RSU disseminates the EWM to the vehicles that holds the high Risk Factor (RF) and travels in High Risk Zone (HRZ). These vehicles might reside either within the RSU’s coverage area or outside RSU’s coverage area (reached using VBN structure). The RAP scheme improves the performance of EWM dissemination in terms of increase in notification and decrease in end-to-end delay. The RAP scheme also reduces infrastructure cost (number of RSUs) by formulating and deploying the VBN structure. The RAP scheme with VBN structure improves notification by 19 percent and end-to-end delay by 14.38 percent for a vehicle density of 160 vehicles. It is also proved from the simulation experiment that the performance of RAP scheme is promising in 4-lane highway roads. PMID:26636576

  8. Securely Connecting Instant Messaging Systems for Ad Hoc Networks to Server Based Systems

    DTIC Science & Technology

    2011-06-01

    protocol, a key establishment scheme based on key trees and Diffie - Hellman key establishment. It dynamically changes the group key whenever group...protocol The encryption key is provided by the MIKE protocol MIKE: Group key distribution protocol based on Diffie - Hellman key exchange Key is provided

  9. HOW GAS-DYNAMIC FLARE MODELS POWERED BY PETSCHEK RECONNECTION DIFFER FROM THOSE WITH AD HOC ENERGY SOURCES

    SciTech Connect

    Longcope, D. W.; Klimchuk, J. A.

    2015-11-10

    Aspects of solar flare dynamics, such as chromospheric evaporation and flare light curves, have long been studied using one-dimensional models of plasma dynamics inside a static flare loop, subjected to some energy input. While extremely successful at explaining the observed characteristics of flares, all such models so far have specified energy input ad hoc, rather than deriving it self-consistently. There is broad consensus that flares are powered by magnetic energy released through reconnection. Recent work has generalized Petschek’s basic reconnection scenario, topological change followed by field line retraction and shock heating, to permit its inclusion in a one-dimensional flare loop model. Here we compare the gas dynamics driven by retraction and shocking to those from more conventional static loop models energized by ad hoc source terms. We find significant differences during the first minute, when retraction leads to larger kinetic energies and produces higher densities at the loop top, while ad hoc heating tends to rarify the loop top. The loop-top density concentration is related to the slow magnetosonic shock, characteristic of Petschek’s model, but persists beyond the retraction phase occurring in the outflow jet. This offers an explanation for observed loop-top sources of X-ray and EUV emission, with advantages over that provided by ad hoc heating scenarios. The cooling phases of the two models are, however, notably similar to one another, suggesting that observations at that stage will yield little information on the nature of energy input.

  10. Use of synthesized data to support complex ad-hoc queries in an enterprise information warehouse: a diabetes use case.

    PubMed

    Rogers, Patrick; Erdal, Selnur; Santangelo, Jennifer; Liu, Jianhua; Schuster, Dara; Kamal, Jyoti

    2008-11-06

    The Ohio State University Medical Center (OSUMC) Information Warehouse (IW) is a comprehensive data warehousing facility incorporating operational, clinical, and biological data sets from multiple enterprise system. It is common for users of the IW to request complex ad-hoc queries that often require significant intervention by data analyst. In response to this challenge, we have designed a workflow that leverages synthesized data elements to support such queries in an more timely, efficient manner.

  11. Report of the Ad Hoc Subgroup on the Impact of Competition in Contracting on Research and Development

    DTIC Science & Technology

    1988-06-01

    NUMBER(O LTG Robert Lunn (US Army Ret), Dr. Barbara Glacel, Ms. Naomi J. McAfee, Mr. John Moore, Mr. Edward A. Miller, Dr. Leon Riebman, Mr. Harrison H...Comments on Terms of Reference and Panel Questions 11. Paper dated 20 Jun 88 submitted by Mr. John R. Moore, Subject: Considerations and Issues... Sculley Assistant Secretary of the Army (Research, Development and Acquisition) I September 1987 PARTICIPANTS LIST ARMY SCIENCE BOARD AD HOC SUBGROUP ON

  12. Ad hoc supervision of general practice registrars as a 'community of practice': analysis, interpretation and re-presentation.

    PubMed

    Clement, T; Brown, J; Morrison, J; Nestel, D

    2016-05-01

    General practice registrars in Australia undertake most of their vocational training in accredited general practices. They typically see patients alone from the start of their community-based training and are expected to seek timely ad hoc support from their supervisor. Such ad hoc encounters are a mechanism for ensuring patient safety, but also provide an opportunity for learning and teaching. Wenger's (Communities of practice: learning, meaning, and identity. Cambridge University Press, New York, 1998) social theory of learning ('communities of practice') guided a secondary analysis of audio-recordings of ad hoc encounters. Data from one encounter is re-presented as an extended sequence to maintain congruence with the theoretical perspective and enhance vicariousness. An interpretive commentary communicates key features of Wenger's theory and highlights the researchers' interpretations. We argue that one encounter can reveal universal understandings of clinical supervision and that the process of naturalistic generalisation allows readers to transfer others' experiences to their own contexts. The paper raises significant analytic, interpretive, and representational issues. We highlight that report writing is an important, but infrequently discussed, part of research design. We discuss the challenges of supporting the learning and teaching that arises from adopting a socio-cultural lens and argue that such a perspective importantly captures the complex range of issues that work-based practitioners have to grapple with. This offers a challenge to how we research and seek to influence work-based learning and teaching in health care settings.

  13. Real-Time QoS Routing Protocols in Wireless Multimedia Sensor Networks: Study and Analysis

    PubMed Central

    Alanazi, Adwan; Elleithy, Khaled

    2015-01-01

    Many routing protocols have been proposed for wireless sensor networks. These routing protocols are almost always based on energy efficiency. However, recent advances in complementary metal-oxide semiconductor (CMOS) cameras and small microphones have led to the development of Wireless Multimedia Sensor Networks (WMSN) as a class of wireless sensor networks which pose additional challenges. The transmission of imaging and video data needs routing protocols with both energy efficiency and Quality of Service (QoS) characteristics in order to guarantee the efficient use of the sensor nodes and effective access to the collected data. Also, with integration of real time applications in Wireless Senor Networks (WSNs), the use of QoS routing protocols is not only becoming a significant topic, but is also gaining the attention of researchers. In designing an efficient QoS routing protocol, the reliability and guarantee of end-to-end delay are critical events while conserving energy. Thus, considerable research has been focused on designing energy efficient and robust QoS routing protocols. In this paper, we present a state of the art research work based on real-time QoS routing protocols for WMSNs that have already been proposed. This paper categorizes the real-time QoS routing protocols into probabilistic and deterministic protocols. In addition, both categories are classified into soft and hard real time protocols by highlighting the QoS issues including the limitations and features of each protocol. Furthermore, we have compared the performance of mobility-aware query based real-time QoS routing protocols from each category using Network Simulator-2 (NS2). This paper also focuses on the design challenges and future research directions as well as highlights the characteristics of each QoS routing protocol. PMID:26364639

  14. Real-Time QoS Routing Protocols in Wireless Multimedia Sensor Networks: Study and Analysis.

    PubMed

    Alanazi, Adwan; Elleithy, Khaled

    2015-09-02

    Many routing protocols have been proposed for wireless sensor networks. These routing protocols are almost always based on energy efficiency. However, recent advances in complementary metal-oxide semiconductor (CMOS) cameras and small microphones have led to the development of Wireless Multimedia Sensor Networks (WMSN) as a class of wireless sensor networks which pose additional challenges. The transmission of imaging and video data needs routing protocols with both energy efficiency and Quality of Service (QoS) characteristics in order to guarantee the efficient use of the sensor nodes and effective access to the collected data. Also, with integration of real time applications in Wireless Senor Networks (WSNs), the use of QoS routing protocols is not only becoming a significant topic, but is also gaining the attention of researchers. In designing an efficient QoS routing protocol, the reliability and guarantee of end-to-end delay are critical events while conserving energy. Thus, considerable research has been focused on designing energy efficient and robust QoS routing protocols. In this paper, we present a state of the art research work based on real-time QoS routing protocols for WMSNs that have already been proposed. This paper categorizes the real-time QoS routing protocols into probabilistic and deterministic protocols. In addition, both categories are classified into soft and hard real time protocols by highlighting the QoS issues including the limitations and features of each protocol. Furthermore, we have compared the performance of mobility-aware query based real-time QoS routing protocols from each category using Network Simulator-2 (NS2). This paper also focuses on the design challenges and future research directions as well as highlights the characteristics of each QoS routing protocol.

  15. Awareness of Emerging Wireless Technologies: Ad-hoc and Personal Area Networks Standards and Emerging Technologies (Sensibilisation a l’emergence des technologies sans fil: technologies emergeantes et normes de reseaux personnels et ad-hoc)

    DTIC Science & Technology

    2007-04-01

    Projet Hipercom – INRIA Rocquencourt. [14] Performance analysis of OLSR Multipoint Relay flooding in two ad hoc wireless network models N°4260...comporter la dénomination « RTO » ou « AGARD » selon le cas, suivi du numéro de série. Des informations analogues, telles que le titre est la date de...RTO » ou « AGARD » selon le cas, suivie du numéro de série (par exemple AGARD-AG-315). Des informations analogues, telles que le titre et la date

  16. On Some Challenges and Design Choices in AD-HOC Communications

    DTIC Science & Technology

    2000-01-25

    were proposed - the Multi-hop Access Collision Avoidance (MACA) [Karn90] protocol and the Media Access Protocol for Wireless LANs ( MACAW ) protocol...stations are avoided. MACAW is an improvement of MACA in the sense that it solves some of the fairness problems in MACA; i.e., in MACA some nodes can...be denied access for a long time. FAMA [Fullmer95] further improves the MACAW performance by including a non-persistent CDMA mechanism at the beginning

  17. Trust Management in Mobile Ad Hoc Networks for Bias Minimization and Application Performance Maximization

    DTIC Science & Technology

    2014-02-26

    an active research area as evidenced by the proliferation of trust/reputation protocols to support mobile group based applications in recent years. In...this paper we address the performance issue of trust management protocol design for MANETs in two important areas: trust bias minimization and...design validation, we identify and validate the best trust protocol settings under which trust bias is minimized and application performance is

  18. Theory and New Primitives for Safely Connecting Routing Protocol Instances

    DTIC Science & Technology

    2010-08-01

    reliability, and load. The current route redistribution procedure handles this incompatibility in a crude fashion. It resets the metric of a redis ...routing instances can also be performed in a link-state manner whereby one routing instance passes on its entire link state database to another...routers B and A, respectively. However, route redis - tribution at multiple points can easily result in routing anomalies [8]. Hence, to support

  19. A neural networks-based hybrid routing protocol for wireless mesh networks.

    PubMed

    Kojić, Nenad; Reljin, Irini; Reljin, Branimir

    2012-01-01

    The networking infrastructure of wireless mesh networks (WMNs) is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic-i.e., neural networks (NNs). This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission). The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance.

  20. A Neural Networks-Based Hybrid Routing Protocol for Wireless Mesh Networks

    PubMed Central

    Kojić, Nenad; Reljin, Irini; Reljin, Branimir

    2012-01-01

    The networking infrastructure of wireless mesh networks (WMNs) is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic—i.e., neural networks (NNs). This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission). The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance. PMID:22969360

  1. Control Based Mobile Ad Hoc Networking for Survivable, Dynamic, Mobile Special Operation Force Communications

    DTIC Science & Technology

    2009-09-01

    Edge Network Technologies ( SAPIENT ) ....................................................... 13 F. NETWORK LAYER...14]. 2. Situational Aware Protocols in Edge Network Technologies ( SAPIENT ) SAPIENT is another program running under DARPA to ease the bandwidth

  2. A comparative study of wireless sensor networks and their routing protocols.

    PubMed

    Bhattacharyya, Debnath; Kim, Tai-hoon; Pal, Subhajit

    2010-01-01

    Recent developments in the area of micro-sensor devices have accelerated advances in the sensor networks field leading to many new protocols specifically designed for wireless sensor networks (WSNs). Wireless sensor networks with hundreds to thousands of sensor nodes can gather information from an unattended location and transmit the gathered data to a particular user, depending on the application. These sensor nodes have some constraints due to their limited energy, storage capacity and computing power. Data are routed from one node to other using different routing protocols. There are a number of routing protocols for wireless sensor networks. In this review article, we discuss the architecture of wireless sensor networks. Further, we categorize the routing protocols according to some key factors and summarize their mode of operation. Finally, we provide a comparative study on these various protocols.

  3. A Comparative Study of Wireless Sensor Networks and Their Routing Protocols

    PubMed Central

    Bhattacharyya, Debnath; Kim, Tai-hoon; Pal, Subhajit

    2010-01-01

    Recent developments in the area of micro-sensor devices have accelerated advances in the sensor networks field leading to many new protocols specifically designed for wireless sensor networks (WSNs). Wireless sensor networks with hundreds to thousands of sensor nodes can gather information from an unattended location and transmit the gathered data to a particular user, depending on the application. These sensor nodes have some constraints due to their limited energy, storage capacity and computing power. Data are routed from one node to other using different routing protocols. There are a number of routing protocols for wireless sensor networks. In this review article, we discuss the architecture of wireless sensor networks. Further, we categorize the routing protocols according to some key factors and summarize their mode of operation. Finally, we provide a comparative study on these various protocols. PMID:22163483

  4. BCDP: Budget Constrained and Delay-Bounded Placement for Hybrid Roadside Units in Vehicular Ad Hoc Networks

    PubMed Central

    Li, Peng; Huang, Chuanhe; Liu, Qin

    2014-01-01

    In vehicular ad hoc networks, roadside units (RSUs) placement has been proposed to improve the the overall network performance in many ITS applications. This paper addresses the budget constrained and delay-bounded placement problem (BCDP) for roadside units in vehicular ad hoc networks. There are two types of RSUs: cable connected RSU (c-RSU) and wireless RSU (w-RSU). c-RSUs are interconnected through wired lines, and they form the backbone of VANETs, while w-RSUs connect to other RSUs through wireless communication and serve as an economical extension of the coverage of c-RSUs. The delay-bounded coverage range and deployment cost of these two cases are totally different. We are given a budget constraint and a delay bound, the problem is how to find the optimal candidate sites with the maximal delay-bounded coverage to place RSUs such that a message from any c-RSU in the region can be disseminated to the more vehicles within the given budget constraint and delay bound. We first prove that the BCDP problem is NP-hard. Then we propose several algorithms to solve the BCDP problem. Simulation results show the heuristic algorithms can significantly improve the coverage range and reduce the total deployment cost, compared with other heuristic methods. PMID:25436656

  5. A Survey on Routing Protocols for Large-Scale Wireless Sensor Networks

    PubMed Central

    Li, Changle; Zhang, Hanxiao; Hao, Binbin; Li, Jiandong

    2011-01-01

    With the advances in micro-electronics, wireless sensor devices have been made much smaller and more integrated, and large-scale wireless sensor networks (WSNs) based the cooperation among the significant amount of nodes have become a hot topic. “Large-scale” means mainly large area or high density of a network. Accordingly the routing protocols must scale well to the network scope extension and node density increases. A sensor node is normally energy-limited and cannot be recharged, and thus its energy consumption has a quite significant effect on the scalability of the protocol. To the best of our knowledge, currently the mainstream methods to solve the energy problem in large-scale WSNs are the hierarchical routing protocols. In a hierarchical routing protocol, all the nodes are divided into several groups with different assignment levels. The nodes within the high level are responsible for data aggregation and management work, and the low level nodes for sensing their surroundings and collecting information. The hierarchical routing protocols are proved to be more energy-efficient than flat ones in which all the nodes play the same role, especially in terms of the data aggregation and the flooding of the control packets. With focus on the hierarchical structure, in this paper we provide an insight into routing protocols designed specifically for large-scale WSNs. According to the different objectives, the protocols are generally classified based on different criteria such as control overhead reduction, energy consumption mitigation and energy balance. In order to gain a comprehensive understanding of each protocol, we highlight their innovative ideas, describe the underlying principles in detail and analyze their advantages and disadvantages. Moreover a comparison of each routing protocol is conducted to demonstrate the differences between the protocols in terms of message complexity, memory requirements, localization, data aggregation, clustering manner

  6. Multiple Path Static Routing Protocols for Packet Switched Networks.

    DTIC Science & Technology

    1983-09-01

    has not yet been used in routing schemes implemented in operating networks, although there are plans to incorporate this procedure in future routing...rules and procedures used to develop loop-frea! routing scheses, are extensions of techniques used in network graph theory and flow pattern analysis. The...parameters of interest, of a process that resembles the actual bahavior of a specific ’ system. Thus an evaluation of its performance and other important

  7. Receiver-Initiated Channel-Hopping for Ad-Hoc Networks

    DTIC Science & Technology

    2000-01-01

    SRMA (split-channel reservation multiple access) was first proposed by Kleinrock and Tobagi [15], including MACA [12], MACAW [2], IEEE 802.11 [1], and...Physical Layer (PHY) Specifications. IEEE, July 1996. [2] Bharghavan, V. and Demers, A. and Shenker, S. and Zhang, L. MACAW : A Media Access Protocol for

  8. Hop-Reservation Multiple Access (HRMA) for Ad-Hoc Networks

    DTIC Science & Technology

    1999-01-01

    5] and MACAW [6]. III. CORRECTNESS OF HRMA The following theorem proves that HRMA eliminates hidden- terminal interference problems. To prove this...Bharghavan, A. Demers, S. Shenker, and L. Zhang, “ MACAW : A Me- dia Access Protocol for Wireless LAN’s,” in Proc. ACM SIGCOMM ’94, pp. 212–25, London

  9. A Secure Routing Protocol for Wireless Sensor Networks Considering Secure Data Aggregation

    PubMed Central

    Rahayu, Triana Mugia; Lee, Sang-Gon; Lee, Hoon-Jae

    2015-01-01

    The commonly unattended and hostile deployments of WSNs and their resource-constrained sensor devices have led to an increasing demand for secure energy-efficient protocols. Routing and data aggregation receive the most attention since they are among the daily network routines. With the awareness of such demand, we found that so far there has been no work that lays out a secure routing protocol as the foundation for a secure data aggregation protocol. We argue that the secure routing role would be rendered useless if the data aggregation scheme built on it is not secure. Conversely, the secure data aggregation protocol needs a secure underlying routing protocol as its foundation in order to be effectively optimal. As an attempt for the solution, we devise an energy-aware protocol based on LEACH and ESPDA that combines secure routing protocol and secure data aggregation protocol. We then evaluate its security effectiveness and its energy-efficiency aspects, knowing that there are always trade-off between both. PMID:26131669

  10. Rapid self-organised initiation of ad hoc sensor networks close above the percolation threshold

    NASA Astrophysics Data System (ADS)

    Korsnes, Reinert

    2010-07-01

    This work shows potentials for rapid self-organisation of sensor networks where nodes collaborate to relay messages to a common data collecting unit (sink node). The study problem is, in the sense of graph theory, to find a shortest path tree spanning a weighted graph. This is a well-studied problem where for example Dijkstra’s algorithm provides a solution for non-negative edge weights. The present contribution shows by simulation examples that simple modifications of known distributed approaches here can provide significant improvements in performance. Phase transition phenomena, which are known to take place in networks close to percolation thresholds, may explain these observations. An initial method, which here serves as reference, assumes the sink node starts organisation of the network (tree) by transmitting a control message advertising its availability for its neighbours. These neighbours then advertise their current cost estimate for routing a message to the sink. A node which in this way receives a message implying an improved route to the sink, advertises its new finding and remembers which neighbouring node the message came from. This activity proceeds until there are no more improvements to advertise to neighbours. The result is a tree network for cost effective transmission of messages to the sink (root). This distributed approach has potential for simple improvements which are of interest when minimisation of storage and communication of network information are a concern. Fast organisation of the network takes place when the number k of connections for each node ( degree) is close above its critical value for global network percolation and at the same time there is a threshold for the nodes to decide to advertise network route updates.

  11. Remote detection of riverine traffic using an ad hoc wireless sensor network

    NASA Astrophysics Data System (ADS)

    Athan, Stephan P.

    2005-05-01

    Trafficking of illegal drugs on riverine and inland waterways continues to proliferate in South America. While there has been a successful joint effort to cut off overland and air trafficking routes, there exists a vast river network and Amazon region consisting of over 13,000 water miles that remains difficult to adequately monitor, increasing the likelihood of narcotics moving along this extensive river system. Hence, an effort is underway to provide remote unattended riverine detection in lieu of manned or attended detection measures.

  12. A survey on investigating the need for intelligent power-aware load balanced routing protocols for handling critical links in MANETs.

    PubMed

    Sivakumar, B; Bhalaji, N; Sivakumar, D

    2014-01-01

    In mobile ad hoc networks connectivity is always an issue of concern. Due to dynamism in the behavior of mobile nodes, efficiency shall be achieved only with the assumption of good network infrastructure. Presence of critical links results in deterioration which should be detected in advance to retain the prevailing communication setup. This paper discusses a short survey on the specialized algorithms and protocols related to energy efficient load balancing for critical link detection in the recent literature. This paper also suggests a machine learning based hybrid power-aware approach for handling critical nodes via load balancing.

  13. A Survey on Investigating the Need for Intelligent Power-Aware Load Balanced Routing Protocols for Handling Critical Links in MANETs

    PubMed Central

    Sivakumar, B.; Bhalaji, N.; Sivakumar, D.

    2014-01-01

    In mobile ad hoc networks connectivity is always an issue of concern. Due to dynamism in the behavior of mobile nodes, efficiency shall be achieved only with the assumption of good network infrastructure. Presence of critical links results in deterioration which should be detected in advance to retain the prevailing communication setup. This paper discusses a short survey on the specialized algorithms and protocols related to energy efficient load balancing for critical link detection in the recent literature. This paper also suggests a machine learning based hybrid power-aware approach for handling critical nodes via load balancing. PMID:24790546

  14. Improving the signal-to-noise ratio of an ECL-based sensor using ad hoc carbon nanotube electrodes

    NASA Astrophysics Data System (ADS)

    Sanginario, A.; Giorcelli, M.; Tagliaferro, A.; Demarchi, D.

    2012-07-01

    In this paper, we demonstrate that mechanically modified cylinder-shaped carbon nanotube (CNT) working electrodes (WEs), combined with an averaging processing algorithm, can increase electrogenerated chemiluminescence (ECL) limit of detection by more than one order of magnitude, compared to gold electrodes. With CNT WEs, we obtained a stable light emission that lasts for hundreds of voltammetric cycles. This stability was further exploited to increase the detection limit with a simple algorithm, based on mean calculation. Ad hoc fabricated sensors are characterized with a full-custom potentiostat testbed and software platform, using tris(2,2-bipyridyl)ruthenium (II) as ECL labels. Our measurement results show that the signal-to-noise ratio (SNR) improves by a factor of larger than 20 compared to standard gold WEs to reach a detection limit up to 40 pg μl-1.

  15. Evaluating the Importance of Image-related Text for Ad-hoc and Case-based Biomedical Article Retrieval.

    PubMed

    Simpson, Matthew S; Demner-Fushman, Dina; Thoma, George R

    2010-11-13

    Images and their associated text are an essential source of information in biomedical articles. However, their use in providing evidence for clinical case descriptions has yet to be evaluated in the context of information retrieval. Given the complexity of case-based document retrieval, understanding the importance of images and image-related text is critical for future research into text- and content-based approaches to this problem. In this study, we compare the extent to which image-related text is useful in facilitating document retrieval for both case-based information requests and ad-hoc clinical questions in the domain of family practice. We show that case-based document retrieval is significantly improved with the use of image-related text whereas retrieval for clinical questions is largely unaffected. This suggests that visual evidence is more relevant for the case descriptions used in our study than the clinical questions.

  16. Potentials, Limitations and Applications of long-term and mobile ad-hoc Wireless Sensor Networks for Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Bumberger, Jan; Mollenhauer, Hannes; Lapteva, Yulia; Hutschenreuther, Tino; Toepfer, Hannes; Dietrich, Peter

    2014-05-01

    To characterize environmental systems it is necessary to identify and describe processes with suitable methods. Environmental systems are often characterized by their high heterogeneity, so individual measurements for their complete representation are often not sufficient. The application of wireless sensor networks in terrestrial and aquatic ecosystems offer significant benefits as a better consideration of the local test conditions becomes possible. This can be essential for the monitoring of heterogeneous environmental systems. Significant advantages in the application of mobile ad-hoc wireless sensor networks are their self-organizing behavior, resulting in a major reduction in installation and operation costs and time. In addition, a point measurement with a sensor is significantly improved by measuring at several points. It is also possible to perform analog and digital signal processing and computation on the basis of the measured data close to the sensor. Hence, a significant reduction of the data to be transmitted can be achieved which leads to a better energy management of sensor nodes. Furthermore, their localization via satellite, the miniaturization of the nodes and long-term energy self-sufficiency are current topics under investigation. The possibilities and limitations of the applicability of wireless sensor networks for long-term and mobile environmental monitoring are presented. A concepts and realization example are given in the field of micrometeorology and soil parameters for the interaction of biotic and abiotic processes .This long term monitoring is part of the Global Change Experimental Facility (GCEF), a large field-based experimental platform to assess the effects of climate change on ecosystem functions and processes under different land-use scenarios. Furthermore a mobile ad-hoc sensor network is presented for the monitoring of water induced mass wasting processes.

  17. Data-Centric Multiobjective QoS-Aware Routing Protocol for Body Sensor Networks

    PubMed Central

    Razzaque, Md. Abdur; Hong, Choong Seon; Lee, Sungwon

    2011-01-01

    In this paper, we address Quality-of-Service (QoS)-aware routing issue for Body Sensor Networks (BSNs) in delay and reliability domains. We propose a data-centric multiobjective QoS-Aware routing protocol, called DMQoS, which facilitates the system to achieve customized QoS services for each traffic category differentiated according to the generated data types. It uses modular design architecture wherein different units operate in coordination to provide multiple QoS services. Their operation exploits geographic locations and QoS performance of the neighbor nodes and implements a localized hop-by-hop routing. Moreover, the protocol ensures (almost) a homogeneous energy dissipation rate for all routing nodes in the network through a multiobjective Lexicographic Optimization-based geographic forwarding. We have performed extensive simulations of the proposed protocol, and the results show that DMQoS has significant performance improvements over several state-of-the-art approaches. PMID:22346611

  18. KHIP - A Scalable Protocol for Secure Multicast Routing

    DTIC Science & Technology

    1999-01-01

    communication between hosts and routers. Today, hosts communicate with their designated multicast router using IGMP . For secure multicast, a secure...version of IGMP needs to be developed [3]. A host could then authenticate with its router using the same four way authentication mechanism described...members and to distribute en- 3Internet Group Management Protocol ( IGMP ) [10] is the protocol that a hosts uses to communicate with an attached router

  19. Comparison of Two Hierarchical Routing Protocols for Heterogeneous MANET

    DTIC Science & Technology

    2007-10-01

    révèlent que le protocole H-OLSR est d’un rendement supérieur au protocole H-LANMAR pour la plupart des scénarios de mobilité de groupe qui portent...bien à une topologie de MANET hétérogène du domaine tactique. Nous recourons à des scénarios de mobilité de groupe qui caractérisent l’exploitation

  20. A Secure Region-Based Geographic Routing Protocol (SRBGR) for Wireless Sensor Networks

    PubMed Central

    Adnan, Ali Idarous; Hanapi, Zurina Mohd; Othman, Mohamed; Zukarnain, Zuriati Ahmad

    2017-01-01

    Due to the lack of dependency for routing initiation and an inadequate allocated sextant on responding messages, the secure geographic routing protocols for Wireless Sensor Networks (WSNs) have attracted considerable attention. However, the existing protocols are more likely to drop packets when legitimate nodes fail to respond to the routing initiation messages while attackers in the allocated sextant manage to respond. Furthermore, these protocols are designed with inefficient collection window and inadequate verification criteria which may lead to a high number of attacker selections. To prevent the failure to find an appropriate relay node and undesirable packet retransmission, this paper presents Secure Region-Based Geographic Routing Protocol (SRBGR) to increase the probability of selecting the appropriate relay node. By extending the allocated sextant and applying different message contention priorities more legitimate nodes can be admitted in the routing process. Moreover, the paper also proposed the bound collection window for a sufficient collection time and verification cost for both attacker identification and isolation. Extensive simulation experiments have been performed to evaluate the performance of the proposed protocol in comparison with other existing protocols. The results demonstrate that SRBGR increases network performance in terms of the packet delivery ratio and isolates attacks such as Sybil and Black hole. PMID:28121992

  1. Routing Algorithm Exploits Spatial Relations

    NASA Technical Reports Server (NTRS)

    Okino, Clayton; Jennings, Esther

    2004-01-01

    A recently developed routing algorithm for broadcasting in an ad hoc wireless communication network takes account of, and exploits, the spatial relationships among the locations of nodes, in addition to transmission power levels and distances between the nodes. In contrast, most prior algorithms for discovering routes through ad hoc networks rely heavily on transmission power levels and utilize limited graph-topology techniques that do not involve consideration of the aforesaid spatial relationships. The present algorithm extracts the relevant spatial-relationship information by use of a construct denoted the relative-neighborhood graph (RNG).

  2. Ad Hoc Influenza Vaccination During Years of Significant Antigenic Drift in a Tropical City With 2 Seasonal Peaks

    PubMed Central

    Wong, Martin C.S.; Nelson, E. Anthony S.; Leung, Czarina; Lee, Nelson; Chan, Martin C.W.; Choi, Kin Wing; Rainer, Timothy H.; Cheng, Frankie W.T.; Wong, Samuel Y.S.; Lai, Christopher K.C.; Lam, Bosco; Cheung, Tak Hong; Leung, Ting Fan; Chan, Paul K.S.

    2016-01-01

    Abstract We evaluated the acceptability of an additional ad hoc influenza vaccination among the health care professionals following seasons with significant antigenic drift. Self-administered, anonymous surveys were performed by hard copy questionnaires in public hospitals, and by an on-line platform available to all healthcare professionals, from April 1st to May 31st, 2015. A total of 1290 healthcare professionals completed the questionnaires, including doctors, nurses, and allied health professionals working in both the public and private systems. Only 31.8% of participating respondents expressed an intention to receive the additional vaccine, despite that the majority of them agreed or strongly agreed that it would bring benefit to the community (88.9%), save lives (86.7%), reduce medical expenses (76.3%), satisfy public expectation (82.8%), and increase awareness of vaccination (86.1%). However, a significant proportion expressed concern that the vaccine could disturb the normal immunization schedule (45.5%); felt uncertain what to do in the next vaccination round (66.0%); perceived that the summer peak might not occur (48.2%); and believed that the summer peak might not be of the same virus (83.5%). Furthermore, 27.8% of all respondents expected that the additional vaccination could weaken the efficacy of previous vaccinations; 51.3% was concerned about side effects; and 61.3% estimated that there would be a low uptake rate. If the supply of vaccine was limited, higher priority groups were considered to include the elderly aged ≥65 years with chronic medical conditions (89.2%), the elderly living in residential care homes (87.4%), and long-stay residents of institutions for the disabled (80.7%). The strongest factors associated with accepting the additional vaccine included immunization with influenza vaccines in the past 3 years, higher perceived risk of contracting influenza, and higher perceived severity of the disease impact. The acceptability to an

  3. Preserving Nevada's Environmental Heritage: A Report of the Ad Hoc Committee on Environmental Quality. Final Report to the Governor's Natural Resources Council.

    ERIC Educational Resources Information Center

    Nevada State Dept. of Conservation and Natural Resources, Carson City.

    The Environmental Quality Ad Hoc Committee has prepared this report for the Governor's Natural Resources Council (Nevada). It is a compilation of available factual data focusing attention on needed statutory and administrative changes to preserve Nevada's environmental heritage and from which recommendations for future budgetary and legislative…

  4. Meeting the Needs of CALS Students for Computing Capabilities. Final Report of the Ad Hoc Committee on College of Agriculture and Life Sciences Student Computing Competencies.

    ERIC Educational Resources Information Center

    Monk, David; And Others

    The Ad Hoc Committee on the Cornell University (New York) College of Agriculture and Life Sciences (CALS) Student Computing Competencies was appointed in the fall of 1995 to determine (1) what all CALS undergraduate students should know about computing and related technologies; (2) how the college can make it possible for students to develop these…

  5. Report on Counseling Evaluation Guidelines Developed by the Ad Hoc Counseling Task Force and Endorsed by the Illinois Community College Board.

    ERIC Educational Resources Information Center

    Illinois Community Coll. Board, Springfield.

    Three years of cooperative effort by participating Illinois community colleges and the Ad Hoc Counseling Task Force resulted in the 1977 approval, by the Illinois Community College Board (ICCB), of a position paper on comprehensive counseling services and in the endorsement of guidelines in four student service areas. The ICCB supports counseling…

  6. A survey on the taxonomy of cluster-based routing protocols for homogeneous wireless sensor networks.

    PubMed

    Naeimi, Soroush; Ghafghazi, Hamidreza; Chow, Chee-Onn; Ishii, Hiroshi

    2012-01-01

    The past few years have witnessed increased interest among researchers in cluster-based protocols for homogeneous networks because of their better scalability and higher energy efficiency than other routing protocols. Given the limited capabilities of sensor nodes in terms of energy resources, processing and communication range, the cluster-based protocols should be compatible with these constraints in either the setup state or steady data transmission state. With focus on these constraints, we classify routing protocols according to their objectives and methods towards addressing the shortcomings of clustering process on each stage of cluster head selection, cluster formation, data aggregation and data communication. We summarize the techniques and methods used in these categories, while the weakness and strength of each protocol is pointed out in details. Furthermore, taxonomy of the protocols in each phase is given to provide a deeper understanding of current clustering approaches. Ultimately based on the existing research, a summary of the issues and solutions of the attributes and characteristics of clustering approaches and some open research areas in cluster-based routing protocols that can be further pursued are provided.

  7. A Survey on the Taxonomy of Cluster-Based Routing Protocols for Homogeneous Wireless Sensor Networks

    PubMed Central

    Naeimi, Soroush; Ghafghazi, Hamidreza; Chow, Chee-Onn; Ishii, Hiroshi

    2012-01-01

    The past few years have witnessed increased interest among researchers in cluster-based protocols for homogeneous networks because of their better scalability and higher energy efficiency than other routing protocols. Given the limited capabilities of sensor nodes in terms of energy resources, processing and communication range, the cluster-based protocols should be compatible with these constraints in either the setup state or steady data transmission state. With focus on these constraints, we classify routing protocols according to their objectives and methods towards addressing the shortcomings of clustering process on each stage of cluster head selection, cluster formation, data aggregation and data communication. We summarize the techniques and methods used in these categories, while the weakness and strength of each protocol is pointed out in details. Furthermore, taxonomy of the protocols in each phase is given to provide a deeper understanding of current clustering approaches. Ultimately based on the existing research, a summary of the issues and solutions of the attributes and characteristics of clustering approaches and some open research areas in cluster-based routing protocols that can be further pursued are provided. PMID:22969350

  8. Dynamic Cooperative Clustering Based Power Assignment: Network Capacity and Lifetime Efficient Topology Control in Cooperative Ad Hoc Networks

    PubMed Central

    Xiao, Ling

    2014-01-01

    Cooperative communication (CC) is used in topology control as it can reduce the transmission power and expand the transmission range. However, all previous research on topology control under the CC model focused on maintaining network connectivity and minimizing the total energy consumption, which would lead to low network capacity, transmission interruption, or even network paralysis. Meanwhile, without considering the balance of energy consumption in the network, it would reduce the network lifetime and greatly affect the network performance. This paper tries to solve the above problems existing in the research on topology control under the CC model by proposing a power assignment (DCCPA) algorithm based on dynamic cooperative clustering in cooperative ad hoc networks. The new algorithm clusters the network to maximize network capacity and makes the clusters communicate with each other by CC. To reduce the number of redundant links between clusters, we design a static clustering method by using Kruskal algorithm. To maximize the network lifetime, we also propose a cluster head rotating method which can reach a good tradeoff between residual energy and distance for the cluster head reselection. Experimental results show that DCCPA can improve 80% network capacity with Cooperative Bridges algorithm; meanwhile, it can improve 20% network lifetime. PMID:24757413

  9. International survey of vestibular rehabilitation therapists by the Barany Society Ad Hoc Committee on Vestibular Rehabilitation Therapy.

    PubMed

    Cohen, Helen S; Gottshall, Kim R; Graziano, Mariella; Malmstrom, Eva-Maj; Sharpe, Margaret H

    2009-01-01

    The goal of this study was to determine how occupational and physical therapists learn about vestibular rehabilitation therapy, their educational backgrounds, referral patterns, and their ideas about entry-level and advanced continuing education in vestibular rehabilitation therapy. The Barany Society Ad Hoc Committee for Vestibular Rehabilitation Therapy invited therapists around the world to complete an E-mail survey. Participants were either known to committee members or other Barany Society members, known to other participants, identified from their self-listings on the Internet, or volunteered after reading notices published in publications read by therapists. Responses were received from 133 therapists in 19 countries. They had a range of educational backgrounds, practice settings, and referral patterns. Few respondents had had any training about vestibular rehabilitation during their professional entry-level education. Most respondents learned about vestibular rehabilitation from continuing education courses, interactions with their colleagues, and reading. All of them endorsed the concept of developing standards and educating therapists about vestibular anatomy and physiology, vestibular diagnostic testing, vestibular disorders and current intervention strategies. Therefore, the Committee recommends the development of international standards for education and practice in vestibular rehabilitation therapy.

  10. Dynamic Key Management Schemes for Secure Group Access Control Using Hierarchical Clustering in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Tsaur, Woei-Jiunn; Pai, Haw-Tyng

    2008-11-01

    The applications of group computing and communication motivate the requirement to provide group access control in mobile ad hoc networks (MANETs). The operation in MANETs' groups performs a decentralized manner and accommodated membership dynamically. Moreover, due to lack of centralized control, MANETs' groups are inherently insecure and vulnerable to attacks from both within and outside the groups. Such features make access control more challenging in MANETs. Recently, several researchers have proposed group access control mechanisms in MANETs based on a variety of threshold signatures. However, these mechanisms cannot actually satisfy MANETs' dynamic environments. This is because the threshold-based mechanisms cannot be achieved when the number of members is not up to the threshold value. Hence, by combining the efficient elliptic curve cryptosystem, self-certified public key cryptosystem and secure filter technique, we construct dynamic key management schemes based on hierarchical clustering for securing group access control in MANETs. Specifically, the proposed schemes can constantly accomplish secure group access control only by renewing the secure filters of few cluster heads, when a cluster head joins or leaves a cross-cluster. In such a new way, we can find that the proposed group access control scheme can be very effective for securing practical applications in MANETs.

  11. Dynamic cooperative clustering based power assignment: network capacity and lifetime efficient topology control in cooperative ad hoc networks.

    PubMed

    Li, Xiao-Hong; Xiao, Ling; Wang, Dong

    2014-01-01

    Cooperative communication (CC) is used in topology control as it can reduce the transmission power and expand the transmission range. However, all previous research on topology control under the CC model focused on maintaining network connectivity and minimizing the total energy consumption, which would lead to low network capacity, transmission interruption, or even network paralysis. Meanwhile, without considering the balance of energy consumption in the network, it would reduce the network lifetime and greatly affect the network performance. This paper tries to solve the above problems existing in the research on topology control under the CC model by proposing a power assignment (DCCPA) algorithm based on dynamic cooperative clustering in cooperative ad hoc networks. The new algorithm clusters the network to maximize network capacity and makes the clusters communicate with each other by CC. To reduce the number of redundant links between clusters, we design a static clustering method by using Kruskal algorithm. To maximize the network lifetime, we also propose a cluster head rotating method which can reach a good tradeoff between residual energy and distance for the cluster head reselection. Experimental results show that DCCPA can improve 80% network capacity with Cooperative Bridges algorithm; meanwhile, it can improve 20% network lifetime.

  12. Extended Virtual Spring Mesh (EVSM): The Distributed Self-Organizing Mobile Ad Hoc Network for Area Exploration

    SciTech Connect

    Kurt Derr

    2011-12-01

    Mobile Ad hoc NETworks (MANETs) are distributed self-organizing networks that can change locations and configure themselves on the fly. This paper focuses on an algorithmic approach for the deployment of a MANET within an enclosed area, such as a building in a disaster scenario, which can provide a robust communication infrastructure for search and rescue operations. While a virtual spring mesh (VSM) algorithm provides scalable, self-organizing, and fault-tolerant capabilities required by aMANET, the VSM lacks the MANET's capabilities of deployment mechanisms for blanket coverage of an area and does not provide an obstacle avoidance mechanism. This paper presents a new technique, an extended VSM (EVSM) algorithm that provides the following novelties: (1) new control laws for exploration and expansion to provide blanket coverage, (2) virtual adaptive springs enabling the mesh to expand as necessary, (3) adapts to communications disturbances by varying the density and movement of mobile nodes, and (4) new metrics to assess the performance of the EVSM algorithm. Simulation results show that EVSM provides up to 16% more coverage and is 3.5 times faster than VSM in environments with eight obstacles.

  13. A Software-Based Network Infrastructure for Mobile Ad Hoc Data Networking in Support of Small Tactical Units Using the SINCGARS Radio

    DTIC Science & Technology

    2006-03-01

    RT- 1523C/D/E) is designed to interface with the serial port of Data Terminal Equipment (DTE), such as a laptop computer, via an RS232 protocol...widest impact, the radio used in this research had to provide this well known interface. In RS232 Data Mode, the RT-1523C/D/E is capable of a maximum...have a route to D. Those that do not have a route will prepare to flood the route request. Route Requests are sent with a Time-To-Live ( TTL ) of

  14. Ad Hoc Rural Regionalism

    ERIC Educational Resources Information Center

    Hamin, Elisabeth M.; Marcucci, Daniel J.

    2008-01-01

    A new regionalism has been much documented and researched for metropolitan areas; this article documents that there is a new rural regionalism as well. In the United States, these groups appear most likely to emerge in areas that are challenged by outcomes characterizing globalization's effects on the rural condition: namely, exurban or…

  15. SEAODV: A Security Enhanced AODV Routing Protocol for Wireless Mesh Networks

    NASA Astrophysics Data System (ADS)

    Li, Celia; Wang, Zhuang; Yang, Cungang

    In this paper, we propose a Security Enhanced AODV routing protocol (SEAODV) for wireless mesh networks (WMN). SEAODV employs Blom's key pre-distribution scheme to compute the pairwise transient key (PTK) through the flooding of enhanced HELLO message and subsequently uses the established PTK to distribute the group transient key (GTK). PTK and GTK authenticate unicast and broadcast routing messages respectively. In WMN, a unique PTK is shared by each pair of nodes, while GTK is shared secretly between the node and all its one-hop neighbours. A message authentication code (MAC) is attached as the extension to the original AODV routing message to guarantee the message's authenticity and integrity in a hop-by-hop fashion. Security analysis and performance evaluation show that SEAODV is more effective in preventing identified routing attacks and outperforms ARAN and SAODV in terms of computation cost and route acquisition latency.

  16. Multi-hop routing mechanism for reliable sensor computing.

    PubMed

    Chen, Jiann-Liang; Ma, Yi-Wei; Lai, Chia-Ping; Hu, Chia-Cheng; Huang, Yueh-Min

    2009-01-01

    Current research on routing in wireless sensor computing concentrates on increasing the service lifetime, enabling scalability for large number of sensors and supporting fault tolerance for battery exhaustion and broken nodes. A sensor node is naturally exposed to various sources of unreliable communication channels and node failures. Sensor nodes have many failure modes, and each failure degrades the network performance. This work develops a novel mechanism, called Reliable Routing Mechanism (RRM), based on a hybrid cluster-based routing protocol to specify the best reliable routing path for sensor computing. Table-driven intra-cluster routing and on-demand inter-cluster routing are combined by changing the relationship between clusters for sensor computing. Applying a reliable routing mechanism in sensor computing can improve routing reliability, maintain low packet loss, minimize management overhead and save energy consumption. Simulation results indicate that the reliability of the proposed RRM mechanism is around 25% higher than that of the Dynamic Source Routing (DSR) and ad hoc On-demand Distance Vector routing (AODV) mechanisms.

  17. Multi-Hop Routing Mechanism for Reliable Sensor Computing

    PubMed Central

    Chen, Jiann-Liang; Ma, Yi-Wei; Lai, Chia-Ping; Hu, Chia-Cheng; Huang, Yueh-Min

    2009-01-01

    Current research on routing in wireless sensor computing concentrates on increasing the service lifetime, enabling scalability for large number of sensors and supporting fault tolerance for battery exhaustion and broken nodes. A sensor node is naturally exposed to various sources of unreliable communication channels and node failures. Sensor nodes have many failure modes, and each failure degrades the network performance. This work develops a novel mechanism, called Reliable Routing Mechanism (RRM), based on a hybrid cluster-based routing protocol to specify the best reliable routing path for sensor computing. Table-driven intra-cluster routing and on-demand inter-cluster routing are combined by changing the relationship between clusters for sensor computing. Applying a reliable routing mechanism in sensor computing can improve routing reliability, maintain low packet loss, minimize management overhead and save energy consumption. Simulation results indicate that the reliability of the proposed RRM mechanism is around 25% higher than that of the Dynamic Source Routing (DSR) and ad hoc On-demand Distance Vector routing (AODV) mechanisms. PMID:22303165

  18. Distributed Dynamic Host Configuration Protocol (D2HCP).

    PubMed

    Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

    2011-01-01

    Mobile Ad Hoc Networks (MANETs) are multihop wireless networks of mobile nodes without any fixed or preexisting infrastructure. The topology of these networks can change randomly due to the unpredictable mobility of nodes and their propagation characteristics. In most networks, including MANETs, each node needs a unique identifier to communicate. This work presents a distributed protocol for dynamic node IP address assignment in MANETs. Nodes of a MANET synchronize from time to time to maintain a record of IP address assignments in the entire network and detect any IP address leaks. The proposed stateful autoconfiguration scheme uses the OLSR proactive routing protocol for synchronization and guarantees unique IP addresses under a variety of network conditions, including message losses and network partitioning. Simulation results show that the protocol incurs low latency and communication overhead for IP address assignment.

  19. Distributed Dynamic Host Configuration Protocol (D2HCP)

    PubMed Central

    Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

    2011-01-01

    Mobile Ad Hoc Networks (MANETs) are multihop wireless networks of mobile nodes without any fixed or preexisting infrastructure. The topology of these networks can change randomly due to the unpredictable mobility of nodes and their propagation characteristics. In most networks, including MANETs, each node needs a unique identifier to communicate. This work presents a distributed protocol for dynamic node IP address assignment in MANETs. Nodes of a MANET synchronize from time to time to maintain a record of IP address assignments in the entire network and detect any IP address leaks. The proposed stateful autoconfiguration scheme uses the OLSR proactive routing protocol for synchronization and guarantees unique IP addresses under a variety of network conditions, including message losses and network partitioning. Simulation results show that the protocol incurs low latency and communication overhead for IP address assignment. PMID:22163856

  20. Analysis of energy efficient routing protocols for implementation of a ubiquitous health system

    NASA Astrophysics Data System (ADS)

    Kwon, Jongwon; Park, Yongman; Koo, Sangjun; Ayurzana, Odgeral; Kim, Hiesik

    2007-12-01

    The innovative Ubiquitous-Health was born through convergence of medical service, with development of up to date information technologies and ubiquitous IT. The U-Health can be applied to a variety of special situations for managing functions of each medical center efficiently. This paper focuses on estimation of various routing protocols for implementation of U-health monitoring system. In order to facilitate wireless communication over the network, a routing protocol on the network layer is used to establish precise and efficient route between sensor nodes so that information acquired from sensors may be delivered in a timely manner. A route establishment should be considered to minimize overhead, data loss and power consumption because wireless networks for U-health are organized by a large number of sensor nodes which are small in size and have limited processing power, memory and battery life. In this paper a overview of wireless sensor network technologies commonly known is described as well as evaluation of three multi hop routing protocols which are flooding, gossiping and modified low energy adaptive clustering hierarchy(LEACH) for use with these networks using TOSSIM simulator. As a result of evaluation the integrated wireless sensor board was developed in particular. The board is embedded device based on AVR128 porting TinyOS. Also it employs bio sensor measures blood pressure, pulse frequency and ZigBee module for wireless communication. This paper accelerates the digital convergence age through continual research and development of technologies related the U-Health.

  1. Adaptive Wireless Ad-hoc Sensor Networks for Long-term and Event-oriented Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Bumberger, Jan; Mollenhauer, Hannes; Remmler, Paul; Schaedler, Martin; Schima, Robert; Mollenhauer, Olaf; Hutschenreuther, Tino; Toepfer, Hannes; Dietrich, Peter

    2015-04-01

    Ecosystems are often characterized by their high heterogeneity, complexity and dynamic. Hence, single point measurements are often not sufficient for their complete representation. The application of wireless sensor networks in terrestrial and aquatic environmental systems offer significant benefits as a better consideration to the local test conditions, due to the simple adjustment of the sensor distribution, the sensor types and the sample rate. Another advantage of wireless ad-hoc sensor networks is their self-organizing behavior, resulting in a major reduction in installation and operation costs and time. In addition, individual point measurements with a sensor are significantly improved by measuring at several points continuously. In this work a concept and realization for Long-term ecosystem research is given in the field monitoring of micrometeorology and soil parameters for the interaction of biotic and abiotic processes. This long term analyses are part of the Global Change Experimental Facility (GCEF), a large field-based experimental platform to assess the effects of climate change on ecosystem functions and processes under different land-use scenarios. Regarding to the adaptive behavior of the network, also a mobile version was developed to overcome the lack of information of temporally and spatially fixed measurements for the detection and recording of highly dynamic or time limited processes. First results of different field campaigns are given to present the potentials and limitations of this application in environmental science, especially for the monitoring of the interaction of biotic and abiotic processes, soil-atmosphere interaction and the validation of remote sensing data.

  2. Adaptive Wireless Ad-hoc Sensor Networks for Long-term and Event-oriented Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Bumberger, Jan; Mollenhauer, Hannes; Remmler, Paul; Chirila, Andrei Marian; Mollenhauer, Olaf; Hutschenreuther, Tino; Toepfer, Hannes; Dietrich, Peter

    2016-04-01

    Ecosystems are often characterized by their high heterogeneity, complexity and dynamic. Hence, single point measurements are often not sufficient for their complete representation. The application of wireless sensor networks in terrestrial and aquatic environmental systems offer significant benefits as a better consideration to the local test conditions, due to the simple adjustment of the sensor distribution, the sensor types and the sample rate. Another advantage of wireless ad-hoc sensor networks is their self-organizing behavior, resulting in a major reduction in installation and operation costs and time. In addition, individual point measurements with a sensor are significantly improved by measuring at several points continuously. In this work a concept and realization for Long-term ecosystem research is given in the field monitoring of micrometeorology and soil parameters for the interaction of biotic and abiotic processes. This long term analyses are part of the Global Change Experimental Facility (GCEF), a large field-based experimental platform to assess the effects of climate change on ecosystem functions and processes under different land-use scenarios. Regarding to the adaptive behavior of the network, also a mobile version was developed to overcome the lack of information of temporally and spatially fixed measurements for the detection and recording of highly dynamic or time limited processes. First results of different field campaigns are given to present the potentials and limitations of this application in environmental science, especially for the monitoring of the interaction of biotic and abiotic processes, soil-atmosphere interaction and the validation of remote sensing data.

  3. Neighboring and Connectivity-Aware Routing in VANETs

    PubMed Central

    Koo, Insoo

    2014-01-01

    A novel position-based routing protocol anchor-based connectivity-aware routing (ACAR) for vehicular ad hoc networks (VANETs) is proposed in this paper to ensure connectivity of routes with more successfully delivered packets. Both buses and cars are considered as vehicular nodes running in both clockwise and anticlockwise directions in a city scenario. Both directions are taken into account for faster communication. ACAR is a hybrid protocol, using both the greedy forwarding approach and the store-carry-and-forward approach to minimize the packet drop rate on the basis of certain assumptions. Our solution to situations that occur when the network is sparse and when any (source or intermediate) node has left its initial position makes this protocol different from those existing in the literature. We consider only vehicle-to-vehicle (V2V) communication in which both the source and destination nodes are moving vehicles. Also, no road-side units are considered. Finally, we compare our protocol with A-STAR (a plausible connectivity-aware routing protocol for city environments), and simulation results in NS-2 show improvement in the number of packets delivered to the destination using fewer hops. Also, we show that ACAR has more successfully-delivered long-distance packets with reasonable packet delay than A-STAR. PMID:24982996

  4. Neighboring and connectivity-aware routing in VANETs.

    PubMed

    Ghafoor, Huma; Koo, Insoo; Gohar, Nasir-ud-Din

    2014-01-01

    A novel position-based routing protocol anchor-based connectivity-aware routing (ACAR) for vehicular ad hoc networks (VANETs) is proposed in this paper to ensure connectivity of routes with more successfully delivered packets. Both buses and cars are considered as vehicular nodes running in both clockwise and anticlockwise directions in a city scenario. Both directions are taken into account for faster communication. ACAR is a hybrid protocol, using both the greedy forwarding approach and the store-carry-and-forward approach to minimize the packet drop rate on the basis of certain assumptions. Our solution to situations that occur when the network is sparse and when any (source or intermediate) node has left its initial position makes this protocol different from those existing in the literature. We consider only vehicle-to-vehicle (V2V) communication in which both the source and destination nodes are moving vehicles. Also, no road-side units are considered. Finally, we compare our protocol with A-STAR (a plausible connectivity-aware routing protocol for city environments), and simulation results in NS-2 show improvement in the number of packets delivered to the destination using fewer hops. Also, we show that ACAR has more successfully-delivered long-distance packets with reasonable packet delay than A-STAR.

  5. Region-Based Collision Avoidance Beaconless Geographic Routing Protocol in Wireless Sensor Networks

    PubMed Central

    Lee, JeongCheol; Park, HoSung; Kang, SeokYoon; Kim, Ki-Il

    2015-01-01

    Due to the lack of dependency on beacon messages for location exchange, the beaconless geographic routing protocol has attracted considerable attention from the research community. However, existing beaconless geographic routing protocols are likely to generate duplicated data packets when multiple winners in the greedy area are selected. Furthermore, these protocols are designed for a uniform sensor field, so they cannot be directly applied to practical irregular sensor fields with partial voids. To prevent the failure of finding a forwarding node and to remove unnecessary duplication, in this paper, we propose a region-based collision avoidance beaconless geographic routing protocol to increase forwarding opportunities for randomly-deployed sensor networks. By employing different contention priorities into the mutually-communicable nodes and the rest of the nodes in the greedy area, every neighbor node in the greedy area can be used for data forwarding without any packet duplication. Moreover, simulation results are given to demonstrate the increased packet delivery ratio and shorten end-to-end delay, rather than well-referred comparative protocols. PMID:26057037

  6. Region-Based Collision Avoidance Beaconless Geographic Routing Protocol in Wireless Sensor Networks.

    PubMed

    Lee, JeongCheol; Park, HoSung; Kang, SeokYoon; Kim, Ki-Il

    2015-06-05

    Due to the lack of dependency on beacon messages for location exchange, the beaconless geographic routing protocol has attracted considerable attention from the research community. However, existing beaconless geographic routing protocols are likely to generate duplicated data packets when multiple winners in the greedy area are selected. Furthermore, these protocols are designed for a uniform sensor field, so they cannot be directly applied to practical irregular sensor fields with partial voids. To prevent the failure of finding a forwarding node and to remove unnecessary duplication, in this paper, we propose a region-based collision avoidance beaconless geographic routing protocol to increase forwarding opportunities for randomly-deployed sensor networks. By employing different contention priorities into the mutually-communicable nodes and the rest of the nodes in the greedy area, every neighbor node in the greedy area can be used for data forwarding without any packet duplication. Moreover, simulation results are given to demonstrate the increased packet delivery ratio and shorten end-to-end delay, rather than well-referred comparative protocols.

  7. Enhancing space data exploitation through advanced data routing protocols

    NASA Astrophysics Data System (ADS)

    Daglis, I. A.; Rontogiannis, A.; Anastasiadis, A.; Sykioti, O.; Balasis, G.; Keramitsoglou, I.; Paronis, D.; Tsaoussidis, V.; Diamantopoulos, S.

    2012-01-01

    Data sharing and access are major issues in space sciences, as they influence the degree of data exploitation. The project "Space-Data Routers", which was initiated recently, has the aim of allowing space agencies, academic institutes and research centres to share space-data generated by single or multiple missions, in an efficient, secure and automated manner. The approach of "Space-Data Routers" relies on space internetworking - and in particular on Delay-Tolerant Networking (DTN), which marks the new era in space communications, unifies space and earth communication infrastructures and delivers a set of tools and protocols for space-data exploitation. The project has started with defining limitations currently imposed by typical space mission scenarios, in which the National Observatory of Athens (NOA) is currently involved, including space exploration, planetary exploration and Earth observation missions. Here we are presenting the mission scenarios and the associated major scientific objectives of "Space-Data Routers", with an emphasis on the Sun-Earth connection and the Mars hyperspectral imaging spectroscopy scenarios. In the case of the Sun-Earth connection scenario, we plan to test and validate the capabilities of Space-Data Routers in providing: a) Simultaneous real- time sampling of space plasmas from multiple points with cost-effective means and measuring of phenomena with higher resolution and better coverage to address outstanding science questions and b) Successful data transmission even in hostile communication conditions. In the case of the Mars hyperspectral imaging spectroscopy scenario we plan to test and validate the capabilities of Space-Data Routers in augmenting the data volume received from Mars Express, through the increase of Mars Express connectivity with ground stations and through the increase of access speed to the hyperspectral data depository.

  8. An Adaptive Jitter Mechanism for Reactive Route Discovery in Sensor Networks

    PubMed Central

    Cordero, Juan Antonio; Yi, Jiazi; Clausen, Thomas

    2014-01-01

    This paper analyses the impact of jitter when applied to route discovery in reactive (on-demand) routing protocols. In multi-hop non-synchronized wireless networks, jitter—a small, random variation in the timing of message emission—is commonly employed, as a means to avoid collisions of simultaneous transmissions by adjacent routers over the same channel. In a reactive routing protocol for sensor and ad hoc networks, jitter is recommended during the route discovery process, specifically, during the network-wide flooding of route request messages, in order to avoid collisions. Commonly, a simple uniform jitter is recommended. Alas, this is not without drawbacks: when applying uniform jitter to the route discovery process, an effect called delay inversion is observed. This paper, first, studies and quantifies this delay inversion effect. Second, this paper proposes an adaptive jitter mechanism, designed to alleviate the delay inversion effect and thereby to reduce the route discovery overhead and (ultimately) allow the routing protocol to find more optimal paths, as compared to uniform jitter. This paper presents both analytical and simulation studies, showing that the proposed adaptive jitter can effectively decrease the cost of route discovery and increase the path quality. PMID:25111238

  9. An adaptive jitter mechanism for reactive route discovery in sensor networks.

    PubMed

    Cordero, Juan Antonio; Yi, Jiazi; Clausen, Thomas

    2014-08-08

    This paper analyses the impact of jitter when applied to route discovery in reactive (on-demand) routing protocols. In multi-hop non-synchronized wireless networks, jitter--a small, random variation in the timing of message emission--is commonly employed, as a means to avoid collisions of simultaneous transmissions by adjacent routers over the same channel. In a reactive routing protocol for sensor and ad hoc networks, jitter is recommended during the route discovery process, specifically, during the network-wide flooding of route request messages, in order to avoid collisions. Commonly, a simple uniform jitter is recommended. Alas, this is not without drawbacks: when applying uniform jitter to the route discovery process, an effect called delay inversion is observed. This paper, first, studies and quantifies this delay inversion effect. Second, this paper proposes an adaptive jitter mechanism, designed to alleviate the delay inversion effect and thereby to reduce the route discovery overhead and (ultimately) allow the routing protocol to find more optimal paths, as compared to uniform jitter. This paper presents both analytical and simulation studies, showing that the proposed adaptive jitter can effectively decrease the cost of route discovery and increase the path quality.

  10. RoCoMAR: robots' controllable mobility aided routing and relay architecture for mobile sensor networks.

    PubMed

    Le, Duc Van; Oh, Hoon; Yoon, Seokhoon

    2013-07-05

    In a practical deployment, mobile sensor network (MSN) suffers from a low performance due to high node mobility, time-varying wireless channel properties, and obstacles between communicating nodes. In order to tackle the problem of low network performance and provide a desired end-to-end data transfer quality, in this paper we propose a novel ad hoc routing and relaying architecture, namely RoCoMAR (Robots' Controllable Mobility Aided Routing) that uses robotic nodes' controllable mobility. RoCoMAR repeatedly performs link reinforcement process with the objective of maximizing the network throughput, in which the link with the lowest quality on the path is identified and replaced with high quality links by placing a robotic node as a relay at an optimal position. The robotic node resigns as a relay if the objective is achieved or no more gain can be obtained with a new relay. Once placed as a relay, the robotic node performs adaptive link maintenance by adjusting its position according to the movements of regular nodes. The simulation results show that RoCoMAR outperforms existing ad hoc routing protocols for MSN in terms of network throughput and end-to-end delay.

  11. Privacy Preserved and Secured Reliable Routing Protocol for Wireless Mesh Networks.

    PubMed

    Meganathan, Navamani Thandava; Palanichamy, Yogesh

    2015-01-01

    Privacy preservation and security provision against internal attacks in wireless mesh networks (WMNs) are more demanding than in wired networks due to the open nature and mobility of certain nodes in the network. Several schemes have been proposed to preserve privacy and provide security in WMNs. To provide complete privacy protection in WMNs, the properties of unobservability, unlinkability, and anonymity are to be ensured during route discovery. These properties can be achieved by implementing group signature and ID-based encryption schemes during route discovery. Due to the characteristics of WMNs, it is more vulnerable to many network layer attacks. Hence, a strong protection is needed to avoid these attacks and this can be achieved by introducing a new Cross-Layer and Subject Logic based Dynamic Reputation (CLSL-DR) mechanism during route discovery. In this paper, we propose a new Privacy preserved and Secured Reliable Routing (PSRR) protocol for WMNs. This protocol incorporates group signature, ID-based encryption schemes, and CLSL-DR mechanism to ensure strong privacy, security, and reliability in WMNs. Simulation results prove this by showing better performance in terms of most of the chosen parameters than the existing protocols.

  12. Privacy Preserved and Secured Reliable Routing Protocol for Wireless Mesh Networks

    PubMed Central

    Thandava Meganathan, Navamani; Palanichamy, Yogesh

    2015-01-01

    Privacy preservation and security provision against internal attacks in wireless mesh networks (WMNs) are more demanding than in wired networks due to the open nature and mobility of certain nodes in the network. Several schemes have been proposed to preserve privacy and provide security in WMNs. To provide complete privacy protection in WMNs, the properties of unobservability, unlinkability, and anonymity are to be ensured during route discovery. These properties can be achieved by implementing group signature and ID-based encryption schemes during route discovery. Due to the characteristics of WMNs, it is more vulnerable to many network layer attacks. Hence, a strong protection is needed to avoid these attacks and this can be achieved by introducing a new Cross-Layer and Subject Logic based Dynamic Reputation (CLSL-DR) mechanism during route discovery. In this paper, we propose a new Privacy preserved and Secured Reliable Routing (PSRR) protocol for WMNs. This protocol incorporates group signature, ID-based encryption schemes, and CLSL-DR mechanism to ensure strong privacy, security, and reliability in WMNs. Simulation results prove this by showing better performance in terms of most of the chosen parameters than the existing protocols. PMID:26484361

  13. Clinician Ratings of Interpreter Mediated Visits in Underserved Primary Care Settings with Ad hoc, In-person Professional, and Video Conferencing Modes

    PubMed Central

    Nápoles, Anna M.; Santoyo-Olsson, Jasmine; Karliner, Leah S.; O’Brien, Helen; Gregorich, Steven E.; Pérez-Stable, Eliseo J.

    2013-01-01

    Language interpretation ameliorates health disparities among underserved limited English-proficient patients, yet few studies have compared clinician satisfaction with these services. Self-administered clinician post-visit surveys compared the quality of interpretation and communication, visit satisfaction, degree of patient engagement, and cultural competence of visits using untrained people acting as interpreters (ad hoc), in-person professional, or video conferencing professional interpretation for 283 visits. Adjusting for clinician and patient characteristics, the quality of interpretation of in-person and video conferencing modes were rated similarly (OR=1.79; 95% CI 0.74, 4.33). The quality of in-person (OR=5.55; 95% CI 1.50, 20.51) and video conferencing (OR=3.10; 95% CI 1.16, 8.31) were rated higher than ad hoc interpretation. Self-assessed cultural competence was better for in-person versus video conferencing interpretation (OR=2.32; 95% CI 1.11, 4.86). Video conferencing interpretation increases access without compromising quality, but cultural nuances may be better addressed by in-person interpreters. Professional interpretation is superior to ad hoc (OR=4.15; 95% CI 1.43, 12.09). PMID:20173271

  14. IJS: An Intelligent Junction Selection Based Routing Protocol for VANET to Support ITS Services.

    PubMed

    Bhoi, Sourav Kumar; Khilar, Pabitra Mohan

    2014-01-01

    Selecting junctions intelligently for data transmission provides better intelligent transportation system (ITS) services. The main problem in vehicular communication is high disturbances of link connectivity due to mobility and less density of vehicles. If link conditions are predicted earlier, then there is a less chance of performance degradation. In this paper, an intelligent junction selection based routing protocol (IJS) is proposed to transmit the data in a quickest path, in which the vehicles are mostly connected and have less link connectivity problem. In this protocol, a helping vehicle is set at every junction to control the communication by predicting link failures or network gaps in a route. Helping vehicle at the junction produces a score for every neighboring junction to forward the data to the destination by considering the current traffic information and selects that junction which has minimum score. IJS protocol is implemented and compared with GyTAR, A-STAR, and GSR routing protocols. Simulation results show that IJS performs better in terms of average end-to-end delay, network gap encounter, and number of hops.

  15. IJS: An Intelligent Junction Selection Based Routing Protocol for VANET to Support ITS Services

    PubMed Central

    Khilar, Pabitra Mohan

    2014-01-01

    Selecting junctions intelligently for data transmission provides better intelligent transportation system (ITS) services. The main problem in vehicular communication is high disturbances of link connectivity due to mobility and less density of vehicles. If link conditions are predicted earlier, then there is a less chance of performance degradation. In this paper, an intelligent junction selection based routing protocol (IJS) is proposed to transmit the data in a quickest path, in which the vehicles are mostly connected and have less link connectivity problem. In this protocol, a helping vehicle is set at every junction to control the communication by predicting link failures or network gaps in a route. Helping vehicle at the junction produces a score for every neighboring junction to forward the data to the destination by considering the current traffic information and selects that junction which has minimum score. IJS protocol is implemented and compared with GyTAR, A-STAR, and GSR routing protocols. Simulation results show that IJS performs better in terms of average end-to-end delay, network gap encounter, and number of hops. PMID:27433485

  16. Minimum expected delay-based routing protocol (MEDR) for Delay Tolerant Mobile Sensor Networks.

    PubMed

    Feng, Yong; Liu, Ming; Wang, Xiaomin; Gong, Haigang

    2010-01-01

    It is a challenging work to develop efficient routing protocols for Delay Tolerant Mobile Sensor Networks (DTMSNs), which have several unique characteristics such as sensor mobility, intermittent connectivity, energy limit, and delay tolerability. In this paper, we propose a new routing protocol called Minimum Expected Delay-based Routing (MEDR) tailored for DTMSNs. MEDR achieves a good routing performance by finding and using the connected paths formed dynamically by mobile sensors. In MEDR, each sensor maintains two important parameters: Minimum Expected Delay (MED) and its expiration time. According to MED, messages will be delivered to the sensor that has at least a connected path with their hosting nodes, and has the shortest expected delay to communication directly with the sink node. Because of the changing network topology, the path is fragile and volatile, so we use the expiration time of MED to indicate the valid time of the path, and avoid wrong transmissions. Simulation results show that the proposed MEDR achieves a higher message delivery ratio with lower transmission overhead and data delivery delay than other DTMSN routing approaches.

  17. Ad-hoc and context-dependent adjustments of selective attention in conflict control: an ERP study with visual probes.

    PubMed

    Nigbur, R; Schneider, J; Sommer, W; Dimigen, O; Stürmer, B

    2015-02-15

    Cognitive conflict control in flanker tasks has often been described using the zoom-lens metaphor of selective attention. However, whether and how selective attention - in terms of suppression and enhancement - operates in this context has remained unclear. To examine the dynamic interplay of selective attention and cognitive control we used electrophysiological measures and presented task-irrelevant visual probe stimuli at foveal, parafoveal, and peripheral display positions. Target-flanker congruency varied either randomly from trial to trial (mixed-block) or block-wise (fixed-block) in order to induce reactive versus proactive control modes, respectively. Three EEG measures were used to capture ad-hoc adjustments within trials as well as effects of context-based predictions: the N1 component of the visual evoked potential (VEP) to probes, the VEP to targets, and the conflict-related midfrontal N2 component. Results from probe-VEPs indicate that enhanced processing of the foveal target rather than suppression of the peripheral flankers supports interference control. In incongruent mixed-block trials VEPs were larger to probes near the targets. In the fixed-blocks probe-VEPs were not modulated, but contrary to the mixed-block the preceding target-related VEP was affected by congruency. Results of the control-related N2 reveal largest amplitudes in the unpredictable context, which did not differentiate for stimulus and response incongruency. In contrast, in the predictable context, N2 amplitudes were reduced overall and differentiated between stimulus and response incongruency. Taken together these results imply that predictability alters interference control by a reconfiguration of stimulus processing. During unpredictable sequences participants adjust their attentional focus dynamically on a trial-by-trial basis as reflected in congruency-dependent probe-VEP-modulation. This reactive control mode also elicits larger N2 amplitudes. In contrast, when task demands

  18. Development of Innovative and Inexpensive Optical Sensors in Wireless Ad-hoc Sensor Networks for Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Mollenhauer, Hannes; Schima, Robert; Assing, Martin; Mollenhauer, Olaf; Dietrich, Peter; Bumberger, Jan

    2015-04-01

    Due to the heterogeneity and dynamic of ecosystems, the observation and monitoring of natural processes necessitate a high temporal and spatial resolution. This also requires inexpensive and adaptive measurements as well as innovative monitoring strategies. To this end, the application of ad-hoc wireless sensor networks holds the potential of creating an adequate monitoring platform. In order to achieve a comprehensive monitoring in space and time with affordability, it is necessary to reduce the sensor costs. Common investigation methods, especially with regard to vegetation processes, are based on optical measurements. In particular, different wavelengths correspond to specific properties of the plants and preserve the possibility to derive information about the ecosystem, e.g. photosynthetic performance or nutrient content. In this context, photosynthetically active radiation (PAR) sensors and hyperspectral sensors are in major use. This work aims the development, evaluation and application of inexpensive but high performance optical sensors for the implementation in wireless sensor networks. Photosynthetically active radiation designates the spectral range from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis. PAR sensors enable the detection of the reflected solar light of the vegetation in the whole PAR wave band. The amount of absorption indicates photosynthetic activity of the plant, with good approximation. Hyperspectral sensors observe specific parts or rather distinct wavelengths of the solar light spectrum and facilitate the determination of the main pigment classes, e.g. Chlorophyll, Carotenoid and Anthocyanin. Due to the specific absorption of certain pigments, a characteristic spectral signature can be seen in the visible part of the electromagnetic spectrum, known as narrow-band peaks. In an analogous manner, also the presence and concentration of different nutrients cause a characteristic spectral

  19. The deployment of routing protocols in distributed control plane of SDN.

    PubMed

    Jingjing, Zhou; Di, Cheng; Weiming, Wang; Rong, Jin; Xiaochun, Wu

    2014-01-01

    Software defined network (SDN) provides a programmable network through decoupling the data plane, control plane, and application plane from the original closed system, thus revolutionizing the existing network architecture to improve the performance and scalability. In this paper, we learned about the distributed characteristics of Kandoo architecture and, meanwhile, improved and optimized Kandoo's two levels of controllers based on ideological inspiration of RCP (routing control platform). Finally, we analyzed the deployment strategies of BGP and OSPF protocol in a distributed control plane of SDN. The simulation results show that our deployment strategies are superior to the traditional routing strategies.

  20. The Deployment of Routing Protocols in Distributed Control Plane of SDN

    PubMed Central

    Jingjing, Zhou; Di, Cheng; Weiming, Wang; Rong, Jin; Xiaochun, Wu

    2014-01-01

    Software defined network (SDN) provides a programmable network through decoupling the data plane, control plane, and application plane from the original closed system, thus revolutionizing the existing network architecture to improve the performance and scalability. In this paper, we learned about the distributed characteristics of Kandoo architecture and, meanwhile, improved and optimized Kandoo's two levels of controllers based on ideological inspiration of RCP (routing control platform). Finally, we analyzed the deployment strategies of BGP and OSPF protocol in a distributed control plane of SDN. The simulation results show that our deployment strategies are superior to the traditional routing strategies. PMID:25250395

  1. Performance Analysis of AODV Routing Protocol for Wireless Sensor Network based Smart Metering

    NASA Astrophysics Data System (ADS)

    >Hasan Farooq, Low Tang Jung,

    2013-06-01

    Today no one can deny the need for Smart Grid and it is being considered as of utmost importance to upgrade outdated electric infrastructure to cope with the ever increasing electric load demand. Wireless Sensor Network (WSN) is considered a promising candidate for internetworking of smart meters with the gateway using mesh topology. This paper investigates the performance of AODV routing protocol for WSN based smart metering deployment. Three case studies are presented to analyze its performance based on four metrics of (i) Packet Delivery Ratio, (ii) Average Energy Consumption of Nodes (iii) Average End-End Delay and (iv) Normalized Routing Load.

  2. A comprehensive survey of energy-aware routing protocols in wireless body area sensor networks.

    PubMed

    Effatparvar, Mehdi; Dehghan, Mehdi; Rahmani, Amir Masoud

    2016-09-01

    Wireless body area sensor network is a special purpose wireless sensor network that, employing wireless sensor nodes in, on, or around the human body, makes it possible to measure biological parameters of a person for specific applications. One of the most fundamental concerns in wireless body sensor networks is accurate routing in order to send data promptly and properly, and therefore overcome some of the challenges. Routing protocols for such networks are affected by a large number of factors including energy, topology, temperature, posture, the radio range of sensors, and appropriate quality of service in sensor nodes. Since energy is highly important in wireless body area sensor networks, and increasing the network lifetime results in benefiting greatly from sensor capabilities, improving routing performance with reduced energy consumption presents a major challenge. This paper aims to study wireless body area sensor networks and the related routing methods. It also presents a thorough, comprehensive review of routing methods in wireless body area sensor networks from the perspective of energy. Furthermore, different routing methods affecting the parameter of energy will be classified and compared according to their advantages and disadvantages. In this paper, fundamental concepts of wireless body area sensor networks are provided, and then the advantages and disadvantages of these networks are investigated. Since one of the most fundamental issues in wireless body sensor networks is to perform routing so as to transmit data precisely and promptly, we discuss the same issue. As a result, we propose a classification of the available relevant literature with respect to the key challenge of energy in the routing process. With this end in view, all important papers published between 2000 and 2015 are classified under eight categories including 'Mobility-Aware', 'Thermal-Aware', 'Restriction of Location and Number of Relays', 'Link-aware', 'Cluster- and Tree

  3. Novel distributed control protocol in dynamic wavelength-routed optical networks

    NASA Astrophysics Data System (ADS)

    Ho, Pin-Han; Mouftah, Hussein T.

    2002-07-01

    This paper solves the problem of path selection for WDM mesh networks with a special focus on the implementation in middle-sized networks, such as metropolitan-area networks (MANs). A novel routing and signaling protocol, called Asynchronous Criticality Avoidance (ACA), is proposed to improve the network performance. With the ACA protocol, a specific set of wavelength channels are defined as critical links between a node pair according to dynamic link-state. Criticality information is defined as the critical links and the associated information, which is coordinated and disseminated by each source node to every other source node as an inter-arrival planning. Routing and wavelength assignment is performed along with the criticality avoidance mechanism, in which path selection process is devised to take the criticality information into consideration. Simulation is conducted in 22- and 30-node networks to examine the proposed approach. The simulation results show that the ACA protocol significantly outperforms the Fixed-Path Least-Congested (FPLC) scheme under the Fixed Alternate Routing architecture with various patterns of alternate paths assigned to each source-destination pair in the networks.

  4. An Efficient Data-Gathering Routing Protocol for Underwater Wireless Sensor Networks.

    PubMed

    Javaid, Nadeem; Ilyas, Naveed; Ahmad, Ashfaq; Alrajeh, Nabil; Qasim, Umar; Khan, Zahoor Ali; Liaqat, Tayyaba; Khan, Majid Iqbal

    2015-11-17

    Most applications of underwater wireless sensor networks (UWSNs) demand reliable data delivery over a longer period in an efficient and timely manner. However, the harsh and unpredictable underwater environment makes routing more challenging as compared to terrestrial WSNs. Most of the existing schemes deploy mobile sensors or a mobile sink (MS) to maximize data gathering. However, the relatively high deployment cost prevents their usage in most applications. Thus, this paper presents an autonomous underwater vehicle (AUV)-aided efficient data-gathering (AEDG) routing protocol for reliable data delivery in UWSNs. To prolong the network lifetime, AEDG employs an AUV for data collection from gateways and uses a shortest path tree (SPT) algorithm while associating sensor nodes with the gateways. The AEDG protocol also limits the number of associated nodes with the gateway nodes to minimize the network energy consumption and to prevent the gateways from overloading. Moreover, gateways are rotated with the passage of time to balance the energy consumption of the network. To prevent data loss, AEDG allows dynamic data collection at the AUV depending on the limited number of member nodes that are associated with each gateway. We also develop a sub-optimal elliptical trajectory of AUV by using a connected dominating set (CDS) to further facilitate network throughput maximization. The performance of the AEDG is validated via simulations, which demonstrate the effectiveness of AEDG in comparison to two existing UWSN routing protocols in terms of the selected performance metrics.

  5. WEAMR — A Weighted Energy Aware Multipath Reliable Routing Mechanism for Hotline-Based WSNs

    PubMed Central

    Tufail, Ali; Qamar, Arslan; Khan, Adil Mehmood; Baig, Waleed Akram; Kim, Ki-Hyung

    2013-01-01

    Reliable source to sink communication is the most important factor for an efficient routing protocol especially in domains of military, healthcare and disaster recovery applications. We present weighted energy aware multipath reliable routing (WEAMR), a novel energy aware multipath routing protocol which utilizes hotline-assisted routing to meet such requirements for mission critical applications. The protocol reduces the number of average hops from source to destination and provides unmatched reliability as compared to well known reactive ad hoc protocols i.e., AODV and AOMDV. Our protocol makes efficient use of network paths based on weighted cost calculation and intelligently selects the best possible paths for data transmissions. The path cost calculation considers end to end number of hops, latency and minimum energy node value in the path. In case of path failure path recalculation is done efficiently with minimum latency and control packets overhead. Our evaluation shows that our proposal provides better end-to-end delivery with less routing overhead and higher packet delivery success ratio compared to AODV and AOMDV. The use of multipath also increases overall life time of WSN network using optimum energy available paths between sender and receiver in WDNs. PMID:23669714

  6. Self-Adaptive Trust Based ABR Protocol for MANETs Using Q-Learning

    PubMed Central

    Jeyapal, Akilandeswari

    2014-01-01

    Mobile ad hoc networks (MANETs) are a collection of mobile nodes with a dynamic topology. MANETs work under scalable conditions for many applications and pose different security challenges. Due to the nomadic nature of nodes, detecting misbehaviour is a complex problem. Nodes also share routing information among the neighbours in order to find the route to the destination. This requires nodes to trust each other. Thus we can state that trust is a key concept in secure routing mechanisms. A number of cryptographic protection techniques based on trust have been proposed. Q-learning is a recently used technique, to achieve adaptive trust in MANETs. In comparison to other machine learning computational intelligence techniques, Q-learning achieves optimal results. Our work focuses on computing a score using Q-learning to weigh the trust of a particular node over associativity based routing (ABR) protocol. Thus secure and stable route is calculated as a weighted average of the trust value of the nodes in the route and associativity ticks ensure the stability of the route. Simulation results show that Q-learning based trust ABR protocol improves packet delivery ratio by 27% and reduces the route selection time by 40% over ABR protocol without trust calculation. PMID:25254243

  7. Self-adaptive trust based ABR protocol for MANETs using Q-learning.

    PubMed

    Kumar, Anitha Vijaya; Jeyapal, Akilandeswari

    2014-01-01

    Mobile ad hoc networks (MANETs) are a collection of mobile nodes with a dynamic topology. MANETs work under scalable conditions for many applications and pose different security challenges. Due to the nomadic nature of nodes, detecting misbehaviour is a complex problem. Nodes also share routing information among the neighbours in order to find the route to the destination. This requires nodes to trust each other. Thus we can state that trust is a key concept in secure routing mechanisms. A number of cryptographic protection techniques based on trust have been proposed. Q-learning is a recently used technique, to achieve adaptive trust in MANETs. In comparison to other machine learning computational intelligence techniques, Q-learning achieves optimal results. Our work focuses on computing a score using Q-learning to weigh the trust of a particular node over associativity based routing (ABR) protocol. Thus secure and stable route is calculated as a weighted average of the trust value of the nodes in the route and associativity ticks ensure the stability of the route. Simulation results show that Q-learning based trust ABR protocol improves packet delivery ratio by 27% and reduces the route selection time by 40% over ABR protocol without trust calculation.

  8. A lightweight neighbor-info-based routing protocol for no-base-station taxi-call system.

    PubMed

    Zhu, Xudong; Wang, Jinhang; Chen, Yunchao

    2014-01-01

    Since the quick topology change and short connection duration, the VANET has had unstable routing and wireless signal quality. This paper proposes a kind of lightweight routing protocol-LNIB for call system without base station, which is applicable to the urban taxis. LNIB maintains and predicts neighbor information dynamically, thus finding the reliable path between the source and the target. This paper describes the protocol in detail and evaluates the performance of this protocol by simulating under different nodes density and speed. The result of evaluation shows that the performance of LNIB is better than AODV which is a classic protocol in taxi-call scene.

  9. A Lightweight Neighbor-Info-Based Routing Protocol for No-Base-Station Taxi-Call System

    PubMed Central

    Zhu, Xudong; Wang, Jinhang; Chen, Yunchao

    2014-01-01

    Since the quick topology change and short connection duration, the VANET has had unstable routing and wireless signal quality. This paper proposes a kind of lightweight routing protocol-LNIB for call system without base station, which is applicable to the urban taxis. LNIB maintains and predicts neighbor information dynamically, thus finding the reliable path between the source and the target. This paper describes the protocol in detail and evaluates the performance of this protocol by simulating under different nodes density and speed. The result of evaluation shows that the performance of LNIB is better than AODV which is a classic protocol in taxi-call scene. PMID:24737984

  10. Energy Consumption and Control Response Evaluations of AODV Routing in WSANs for Building-Temperature Control

    PubMed Central

    Booranawong, Apidet; Teerapabkajorndet, Wiklom; Limsakul, Chusak

    2013-01-01

    The main objective of this paper is to investigate the effects of routing protocols on wireless sensor and actuator networks (WSANs), focusing on the control system response and the energy consumption of nodes in a network. We demonstrate that routing algorithms designed without considering the relationship between communication and control cannot be appropriately used in wireless networked control applications. For this purpose, an ad-hoc on-demand distance vector (AODV) routing, an IEEE 802.15.4, and a building-temperature control system are employed for this exploration. The findings from our scenarios show that the AODV routing can select a path with a high traffic load for data transmission. It takes a long time before deciding to change a new route although it experiences the unsuccessful transmission of packets. As a result, the desirable control target cannot be achieved in time, and nodes consume more energy due to frequent packet collisions and retransmissions. Consequently, we propose a simple routing solution to alleviate these research problems by modifying the original AODV routing protocol. The delay-threshold is considered to avoid any congested connection during routing procedures. The simulation results demonstrate that our solution can be appropriately applied in WSANs. Both the energy consumption and the control system response are improved. PMID:23807689

  11. A routing protocol based on energy and link quality for Internet of Things applications.

    PubMed

    Machado, Kássio; Rosário, Denis; Cerqueira, Eduardo; Loureiro, Antonio A F; Neto, Augusto; Souza, José Neuman de

    2013-02-04

    The Internet of Things (IoT) is attracting considerable attention from the universities, industries, citizens and governments for applications, such as healthcare, environmental monitoring and smart buildings. IoT enables network connectivity between smart devices at all times, everywhere, and about everything. In this context, Wireless Sensor Networks (WSNs) play an important role in increasing the ubiquity of networks with smart devices that are low-cost and easy to deploy. However, sensor nodes are restricted in terms of energy, processing and memory. Additionally, low-power radios are very sensitive to noise, interference and multipath distortions. In this context, this article proposes a routing protocol based on Routing by Energy and Link quality (REL) for IoT applications. To increase reliability and energy-efficiency, REL selects routes on the basis of a proposed end-to-end link quality estimator mechanism, residual energy and hop count. Furthermore, REL proposes an event-driven mechanism to provide load balancing and avoid the premature energy depletion of nodes/networks. Performance evaluations were carried out using simulation and testbed experiments to show the impact and benefits of REL in small and large-scale networks. The results show that REL increases the network lifetime and services availability, as well as the quality of service of IoT applications. It also provides an even distribution of scarce network resources and reduces the packet loss rate, compared with the performance of well-known protocols.

  12. A Routing Protocol Based on Energy and Link Quality for Internet of Things Applications

    PubMed Central

    Machado, Kassio; Rosário, Denis; Cerqueira, Eduardo; Loureiro, Antonio A. F.; Neto, Augusto; de Souza, José Neuman

    2013-01-01

    The Internet of Things (IoT) is attracting considerable attention from the universities, industries, citizens and governments for applications, such as healthcare,environmental monitoring and smart buildings. IoT enables network connectivity between smart devices at all times, everywhere, and about everything. In this context, Wireless Sensor Networks (WSNs) play an important role in increasing the ubiquity of networks with smart devices that are low-cost and easy to deploy. However, sensor nodes are restricted in terms of energy, processing and memory. Additionally, low-power radios are very sensitive to noise, interference and multipath distortions. In this context, this article proposes a routing protocol based on Routing by Energy and Link quality (REL) for IoT applications. To increase reliability and energy-efficiency, REL selects routes on the basis of a proposed end-to-end link quality estimator mechanism, residual energy and hop count. Furthermore, REL proposes an event-driven mechanism to provide load balancing and avoid the premature energy depletion of nodes/networks. Performance evaluations were carried out using simulation and testbed experiments to show the impact and benefits of REL in small and large-scale networks. The results show that REL increases the network lifetime and services availability, as well as the quality of service of IoT applications. It also provides an even distribution of scarce network resources and reduces the packet loss rate, compared with the performance of well-known protocols. PMID:23385410

  13. Modeling and Simulation of a Novel Relay Node Based Secure Routing Protocol Using Multiple Mobile Sink for Wireless Sensor Networks

    PubMed Central

    Perumal, Madhumathy; Dhandapani, Sivakumar

    2015-01-01

    Data gathering and optimal path selection for wireless sensor networks (WSN) using existing protocols result in collision. Increase in collision further increases the possibility of packet drop. Thus there is a necessity to eliminate collision during data aggregation. Increasing the efficiency is the need of the hour with maximum security. This paper is an effort to come up with a reliable and energy efficient WSN routing and secure protocol with minimum delay. This technique is named as relay node based secure routing protocol for multiple mobile sink (RSRPMS). This protocol finds the rendezvous point for optimal transmission of data using a “splitting tree” technique in tree-shaped network topology and then to determine all the subsequent positions of a sink the “Biased Random Walk” model is used. In case of an event, the sink gathers the data from all sources, when they are in the sensing range of rendezvous point. Otherwise relay node is selected from its neighbor to transfer packets from rendezvous point to sink. A symmetric key cryptography is used for secure transmission. The proposed relay node based secure routing protocol for multiple mobile sink (RSRPMS) is experimented and simulation results are compared with Intelligent Agent-Based Routing (IAR) protocol to prove that there is increase in the network lifetime compared with other routing protocols. PMID:26495426

  14. Modeling and Simulation of a Novel Relay Node Based Secure Routing Protocol Using Multiple Mobile Sink for Wireless Sensor Networks.

    PubMed

    Perumal, Madhumathy; Dhandapani, Sivakumar

    2015-01-01

    Data gathering and optimal path selection for wireless sensor networks (WSN) using existing protocols result in collision. Increase in collision further increases the possibility of packet drop. Thus there is a necessity to eliminate collision during data aggregation. Increasing the efficiency is the need of the hour with maximum security. This paper is an effort to come up with a reliable and energy efficient WSN routing and secure protocol with minimum delay. This technique is named as relay node based secure routing protocol for multiple mobile sink (RSRPMS). This protocol finds the rendezvous point for optimal transmission of data using a "splitting tree" technique in tree-shaped network topology and then to determine all the subsequent positions of a sink the "Biased Random Walk" model is used. In case of an event, the sink gathers the data from all sources, when they are in the sensing range of rendezvous point. Otherwise relay node is selected from its neighbor to transfer packets from rendezvous point to sink. A symmetric key cryptography is used for secure transmission. The proposed relay node based secure routing protocol for multiple mobile sink (RSRPMS) is experimented and simulation results are compared with Intelligent Agent-Based Routing (IAR) protocol to prove that there is increase in the network lifetime compared with other routing protocols.

  15. Discrete Particle Swarm Optimization Routing Protocol for Wireless Sensor Networks with Multiple Mobile Sinks

    PubMed Central

    Yang, Jin; Liu, Fagui; Cao, Jianneng; Wang, Liangming

    2016-01-01

    Mobile sinks can achieve load-balancing and energy-consumption balancing across the wireless sensor networks (WSNs). However, the frequent change of the paths between source nodes and the sinks caused by sink mobility introduces significant overhead in terms of energy and packet delays. To enhance network performance of WSNs with mobile sinks (MWSNs), we present an efficient routing strategy, which is formulated as an optimization problem and employs the particle swarm optimization algorithm (PSO) to build the optimal routing paths. However, the conventional PSO is insufficient to solve discrete routing optimization problems. Therefore, a novel greedy discrete particle swarm optimization with memory (GMDPSO) is put forward to address this problem. In the GMDPSO, particle’s position and velocity of traditional PSO are redefined under discrete MWSNs scenario. Particle updating rule is also reconsidered based on the subnetwork topology of MWSNs. Besides, by improving the greedy forwarding routing, a greedy search strategy is designed to drive particles to find a better position quickly. Furthermore, searching history is memorized to accelerate convergence. Simulation results demonstrate that our new protocol significantly improves the robustness and adapts to rapid topological changes with multiple mobile sinks, while efficiently reducing the communication overhead and the energy consumption. PMID:27428971

  16. Modeling and Analysis of Intrusion Detection Integrated with Batch Rekeying for Dynamic Group Communication Systems in Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-05-01

    Diffie - Hellman Key Distribution Extended to Group Communication,” Proc. of 3rd ACM Conf. on Computer and Communications Security, New Delhi, India, Jan... Diffie -Hallman (GDH) algorithm [23] as the CKA protocol for group members to generate and distribute a new group key upon a group membership change event

  17. Fundamental lifetime mechanisms in routing protocols for wireless sensor networks: a survey and open issues.

    PubMed

    Eslaminejad, Mohammadreza; Razak, Shukor Abd

    2012-10-09

    Wireless sensor networks basically consist of low cost sensor nodes which collect data from environment and relay them to a sink, where they will be subsequently processed. Since wireless nodes are severely power-constrained, the major concern is how to conserve the nodes' energy so that network lifetime can be extended significantly. Employing one static sink can rapidly exhaust the energy of sink neighbors. Furthermore, using a non-optimal single path together with a maximum transmission power level may quickly deplete the energy of individual nodes on the route. This all results in unbalanced energy consumption through the sensor field, and hence a negative effect on the network lifetime. In this paper, we present a comprehensive taxonomy of the various mechanisms applied for increasing the network lifetime. These techniques, whether in the routing or cross-layer area, fall within the following types: multi-sink, mobile sink, multi-path, power control and bio-inspired algorithms, depending on the protocol operation. In this taxonomy, special attention has been devoted to the multi-sink, power control and bio-inspired algorithms, which have not yet received much consideration in the literature. Moreover, each class covers a variety of the state-of-the-art protocols, which should provide ideas for potential future works. Finally, we compare these mechanisms and discuss open research issues.

  18. Fundamental Lifetime Mechanisms in Routing Protocols for Wireless Sensor Networks: A Survey and Open Issues

    PubMed Central

    Eslaminejad, Mohammadreza; Razak, Shukor Abd

    2012-01-01

    Wireless sensor networks basically consist of low cost sensor nodes which collect data from environment and relay them to a sink, where they will be subsequently processed. Since wireless nodes are severely power-constrained, the major concern is how to conserve the nodes' energy so that network lifetime can be extended significantly. Employing one static sink can rapidly exhaust the energy of sink neighbors. Furthermore, using a non-optimal single path together with a maximum transmission power level may quickly deplete the energy of individual nodes on the route. This all results in unbalanced energy consumption through the sensor field, and hence a negative effect on the network lifetime. In this paper, we present a comprehensive taxonomy of the various mechanisms applied for increasing the network lifetime. These techniques, whether in the routing or cross-layer area, fall within the following types: multi-sink, mobile sink, multi-path, power control and bio-inspired algorithms, depending on the protocol operation. In this taxonomy, special attention has been devoted to the multi-sink, power control and bio-inspired algorithms, which have not yet received much consideration in the literature. Moreover, each class covers a variety of the state-of-the-art protocols, which should provide ideas for potential future works. Finally, we compare these mechanisms and discuss open research issues. PMID:23202008

  19. Reliable Freestanding Position-Based Routing in Highway Scenarios

    PubMed Central

    Galaviz-Mosqueda, Gabriel A.; Aquino-Santos, Raúl; Villarreal-Reyes, Salvador; Rivera-Rodríguez, Raúl; Villaseñor-González, Luis; Edwards, Arthur

    2012-01-01

    Vehicular Ad Hoc Networks (VANETs) are considered by car manufacturers and the research community as the enabling technology to radically improve the safety, efficiency and comfort of everyday driving. However, before VANET technology can fulfill all its expected potential, several difficulties must be addressed. One key issue arising when working with VANETs is the complexity of the networking protocols compared to those used by traditional infrastructure networks. Therefore, proper design of the routing strategy becomes a main issue for the effective deployment of VANETs. In this paper, a reliable freestanding position-based routing algorithm (FPBR) for highway scenarios is proposed. For this scenario, several important issues such as the high mobility of vehicles and the propagation conditions may affect the performance of the routing strategy. These constraints have only been partially addressed in previous proposals. In contrast, the design approach used for developing FPBR considered the constraints imposed by a highway scenario and implements mechanisms to overcome them. FPBR performance is compared to one of the leading protocols for highway scenarios. Performance metrics show that FPBR yields similar results when considering freespace propagation conditions, and outperforms the leading protocol when considering a realistic highway path loss model. PMID:23202159

  20. Reliable freestanding position-based routing in highway scenarios.

    PubMed

    Galaviz-Mosqueda, Gabriel A; Aquino-Santos, Raúl; Villarreal-Reyes, Salvador; Rivera-Rodríguez, Raúl; Villaseñor-González, Luis; Edwards, Arthur

    2012-10-24

    Vehicular Ad Hoc Networks (VANETs) are considered by car manufacturers and the research community as the enabling technology to radically improve the safety, efficiency and comfort of everyday driving. However, before VANET technology can fulfill all its expected potential, several difficulties must be addressed. One key issue arising when working with VANETs is the complexity of the networking protocols compared to those used by traditional infrastructure networks. Therefore, proper design of the routing strategy becomes a main issue for the effective deployment of VANETs. In this paper, a reliable freestanding position-based routing algorithm (FPBR) for highway scenarios is proposed. For this scenario, several important issues such as the high mobility of vehicles and the propagation conditions may affect the performance of the routing strategy. These constraints have only been partially addressed in previous proposals. In contrast, the design approach used for developing FPBR considered the constraints imposed by a highway scenario and implements mechanisms to overcome them. FPBR performance is compared to one of the leading protocols for highway scenarios. Performance metrics show that FPBR yields similar results when considering freespace propagation conditions, and outperforms the leading protocol when considering a realistic highway path loss model.

  1. A Multipath Routing Protocol Based on Clustering and Ant Colony Optimization for Wireless Sensor Networks

    PubMed Central

    Yang, Jing; Xu, Mai; Zhao, Wei; Xu, Baoguo

    2010-01-01

    For monitoring burst events in a kind of reactive wireless sensor networks (WSNs), a multipath routing protocol (MRP) based on dynamic clustering and ant colony optimization (ACO) is proposed. Such an approach can maximize the network lifetime and reduce the energy consumption. An important attribute of WSNs is their limited power supply, and therefore some metrics (such as energy consumption of communication among nodes, residual energy, path length) were considered as very important criteria while designing routing in the MRP. Firstly, a cluster head (CH) is selected among nodes located in the event area according to some parameters, such as residual energy. Secondly, an improved ACO algorithm is applied in the search for multiple paths between the CH and sink node. Finally, the CH dynamically chooses a route to transmit data with a probability that depends on many path metrics, such as energy consumption. The simulation results show that MRP can prolong the network lifetime, as well as balance of energy consumption among nodes and reduce the average energy consumption effectively. PMID:22399890

  2. CENTERA: A Centralized Trust-Based Efficient Routing Protocol with Authentication for Wireless Sensor Networks †

    PubMed Central

    Tajeddine, Ayman; Kayssi, Ayman; Chehab, Ali; Elhajj, Imad; Itani, Wassim

    2015-01-01

    In this paper, we present CENTERA, a CENtralized Trust-based Efficient Routing protocol with an appropriate authentication scheme for wireless sensor networks (WSN). CENTERA utilizes the more powerful base station (BS) to gather minimal neighbor trust information from nodes and calculate the best routes after isolating different types of “bad” nodes. By periodically accumulating these simple local observations and approximating the nodes' battery lives, the BS draws a global view of the network, calculates three quality metrics—maliciousness, cooperation, and compatibility—and evaluates the Data Trust and Forwarding Trust values of each node. Based on these metrics, the BS isolates “bad”, “misbehaving” or malicious nodes for a certain period, and put some nodes on probation. CENTERA increases the node's bad/probation level with repeated “bad” behavior, and decreases it otherwise. Then it uses a very efficient method to distribute the routing information to “good” nodes. Based on its target environment, and if required, CENTERA uses an authentication scheme suitable for severely constrained nodes, ranging from the symmetric RC5 for safe environments under close administration, to pairing-based cryptography (PBC) for hostile environments with a strong attacker model. We simulate CENTERA using TOSSIM and verify its correctness and show some energy calculations. PMID:25648712

  3. CENTERA: a centralized trust-based efficient routing protocol with authentication for wireless sensor networks.

    PubMed

    Tajeddine, Ayman; Kayssi, Ayman; Chehab, Ali; Elhajj, Imad; Itani, Wassim

    2015-02-02

    In this paper, we present CENTERA, a CENtralized Trust-based Efficient Routing protocol with an appropriate authentication scheme for wireless sensor networks (WSN). CENTERA utilizes the more powerful base station (BS) to gather minimal neighbor trust information from nodes and calculate the best routes after isolating different types of "bad" nodes. By periodically accumulating these simple local observations and approximating the nodes' battery lives, the BS draws a global view of the network, calculates three quality metrics-maliciousness, cooperation, and compatibility-and evaluates the Data Trust and Forwarding Trust values of each node. Based on these metrics, the BS isolates "bad", "misbehaving" or malicious nodes for a certain period, and put some nodes on probation. CENTERA increases the node's bad/probation level with repeated "bad" behavior, and decreases it otherwise. Then it uses a very efficient method to distribute the routing information to "good" nodes. Based on its target environment, and if required, CENTERA uses an authentication scheme suitable for severely constrained nodes, ranging from the symmetric RC5 for safe environments under close administration, to pairing-based cryptography (PBC) for hostile environments with a strong attacker model. We simulate CENTERA using TOSSIM and verify its correctness and show some energy calculations.

  4. Exploration of α1-antitrypsin treatment protocol for islet transplantation: dosing plan and route of administration.

    PubMed

    Baranovski, Boris M; Ozeri, Eyal; Shahaf, Galit; Ochayon, David E; Schuster, Ronen; Bahar, Nofar; Kalay, Noa; Cal, Pablo; Mizrahi, Mark I; Nisim, Omer; Strauss, Pnina; Schenker, Eran; Lewis, Eli C

    2016-11-07

    Life-long weekly infusions of human α1-antitrypsin (hAAT) are currently administered as augmentation therapy for patients with genetic AAT deficiency (AATD). Several recent clinical trials attempt to extend hAAT therapy to conditions outside AATD, including type 1 diabetes. Since the endpoint for AATD is primarily the reduction of risk for pulmonary emphysema, the present study explores hAAT dose protocols and routes of administration in attempt to optimize hAAT therapy for islet-related injury. Islet-grafted mice were treated with hAAT (Glassia™; i.p. or s.c.) under an array of clinically relevant dosing plans. Serum hAAT and immunocyte cell membrane association were examined, as well as parameters of islet survival. Results indicate that dividing the commonly prescribed 60 mg/kg i.p. dose to three 20 mg/kg injections is superior in affording islet graft survival; in addition, a short dynamic descending dose protocol (240→120→60→60 mg/kg i.p.) is comparable in outcomes to indefinite 60 mg/kg injections. While hAAT pharmacokinetics after i.p. administration in mice resembles exogenous hAAT treatment in humans, s.c. administration better imitated the physiological progressive rise of hAAT during acute phase responses; nonetheless, only the 60 mg/kg dose depicted an advantage using the s.c. route. Taken together, this study provides a platform for extrapolating an islet-relevant clinical protocol from animal models that use hAAT to protect islets. In addition, the study places emphasis on outcome-oriented analyses of drug efficacy, particularly important when considering that hAAT is presently at an era of drug-repurposing towards an extended list of clinical indications outside genetic AATD.

  5. Exploration of α1-Antitrypsin Treatment Protocol for Islet Transplantation: Dosing Plan and Route of Administration

    PubMed Central

    Baranovski, Boris M.; Ozeri, Eyal; Shahaf, Galit; Ochayon, David E.; Schuster, Ronen; Bahar, Nofar; Kalay, Noa; Cal, Pablo; Mizrahi, Mark I.; Nisim, Omer; Strauss, Pnina; Schenker, Eran

    2016-01-01

    Lifelong weekly infusions of human α1-antitrypsin (hAAT) are currently administered as augmentation therapy for patients with genetic AAT deficiency (AATD). Several recent clinical trials attempt to extend hAAT therapy to conditions outside AATD, including type 1 diabetes. Because the endpoint for AATD is primarily the reduction of risk for pulmonary emphysema, the present study explores hAAT dose protocols and routes of administration in attempt to optimize hAAT therapy for islet-related injury. Islet-grafted mice were treated with hAAT (Glassia; intraperitoneally or subcutaneously) under an array of clinically relevant dosing plans. Serum hAAT and immunocyte cell membrane association were examined, as well as parameters of islet survival. Results indicate that dividing the commonly prescribed 60 mg/kg i.p. dose to three 20 mg/kg injections is superior in affording islet graft survival; in addition, a short dynamic descending dose protocol (240→120→60→60 mg/kg i.p.) is comparable in outcomes to indefinite 60 mg/kg injections. Although pharmacokinetics after intraperitoneal administration in mice resembles exogenous hAAT treatment in humans, subcutaneous administration better imitated the physiologic progressive rise of hAAT during acute phase responses; nonetheless, only the 60 mg/kg dose depicted an advantage using the subcutaneous route. Taken together, this study provides a platform for extrapolating an islet-relevant clinical protocol from animal models that use hAAT to protect islets. In addition, the study places emphasis on outcome-oriented analyses of drug efficacy, particularly important when considering that hAAT is presently at an era of drug-repurposing toward an extended list of clinical indications outside genetic AATD. PMID:27821710

  6. Adaptive MANET Multipath Routing Algorithm Based on the Simulated Annealing Approach

    PubMed Central

    Kim, Sungwook

    2014-01-01

    Mobile ad hoc network represents a system of wireless mobile nodes that can freely and dynamically self-organize network topologies without any preexisting communication infrastructure. Due to characteristics like temporary topology and absence of centralized authority, routing is one of the major issues in ad hoc networks. In this paper, a new multipath routing scheme is proposed by employing simulated annealing approach. The proposed metaheuristic approach can achieve greater and reciprocal advantages in a hostile dynamic real world network situation. Therefore, the proposed routing scheme is a powerful method for finding an effective solution into the conflict mobile ad hoc network routing problem. Simulation results indicate that the proposed paradigm adapts best to the variation of dynamic network situations. The average remaining energy, network throughput, packet loss probability, and traffic load distribution are improved by about 10%, 10%, 5%, and 10%, respectively, more than the existing schemes. PMID:25032241

  7. LOPP: A Location Privacy Protected Anonymous Routing Protocol for Disruption Tolerant Network

    NASA Astrophysics Data System (ADS)

    Lu, Xiaofeng; Hui, Pan; Towsley, Don; Pu, Juhua; Xiong, Zhang

    In this paper, we propose an anonymous routing protocol, LOPP, to protect the originator's location privacy in Delay/Disruption Tolerant Network (DTN). The goals of our study are to minimize the originator's probability of being localized (Pl) and maximize the destination's probability of receiving the message (Pr). The idea of LOPP is to divide a sensitive message into k segments and send each of them to n different neighbors. Although message fragmentation could reduce the destination's probability to receive a complete message, LOPP can decrease the originator's Pl. We validate LOPP on a real-world human mobility dataset. The simulation results show that LOPP can decrease the originator's Pl by over 54% with only 5.7% decrease in destination's Pr. We address the physical localization issue of DTN, which was not studied in the literature.

  8. Towards a hybrid energy efficient multi-tree-based optimized routing protocol for wireless networks.

    PubMed

    Mitton, Nathalie; Razafindralambo, Tahiry; Simplot-Ryl, David; Stojmenovic, Ivan

    2012-12-13

    This paper considers the problem of designing power efficient routing with guaranteed delivery for sensor networks with unknown geographic locations. We propose HECTOR, a hybrid energy efficient tree-based optimized routing protocol, based on two sets of virtual coordinates. One set is based on rooted tree coordinates, and the other is based on hop distances toward several landmarks. In HECTOR, the node currently holding the packet forwards it to its neighbor that optimizes ratio of power cost over distance progress with landmark coordinates, among nodes that reduce landmark coordinates and do not increase distance in tree coordinates. If such a node does not exist, then forwarding is made to the neighbor that reduces tree-based distance only and optimizes power cost over tree distance progress ratio. We theoretically prove the packet delivery and propose an extension based on the use of multiple trees. Our simulations show the superiority of our algorithm over existing alternatives while guaranteeing delivery, and only up to 30% additional power compared to centralized shortest weighted path algorithm.

  9. AURP: An AUV-Aided Underwater Routing Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Yoon, Seokhoon; Azad, Abul K.; Oh, Hoon; Kim, Sunghwan

    2012-01-01

    Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved. PMID:22438740

  10. An empirical evaluation of lightweight random walk based routing protocol in duty cycle aware wireless sensor networks.

    PubMed

    Mian, Adnan Noor; Fatima, Mehwish; Khan, Raees; Prakash, Ravi

    2014-01-01

    Energy efficiency is an important design paradigm in Wireless Sensor Networks (WSNs) and its consumption in dynamic environment is even more critical. Duty cycling of sensor nodes is used to address the energy consumption problem. However, along with advantages, duty cycle aware networks introduce some complexities like synchronization and latency. Due to their inherent characteristics, many traditional routing protocols show low performance in densely deployed WSNs with duty cycle awareness, when sensor nodes are supposed to have high mobility. In this paper we first present a three messages exchange Lightweight Random Walk Routing (LRWR) protocol and then evaluate its performance in WSNs for routing low data rate packets. Through NS-2 based simulations, we examine the LRWR protocol by comparing it with DYMO, a widely used WSN protocol, in both static and dynamic environments with varying duty cycles, assuming the standard IEEE 802.15.4 in lower layers. Results for the three metrics, that is, reliability, end-to-end delay, and energy consumption, show that LRWR protocol outperforms DYMO in scalability, mobility, and robustness, showing this protocol as a suitable choice in low duty cycle and dense WSNs.

  11. An Empirical Evaluation of Lightweight Random Walk Based Routing Protocol in Duty Cycle Aware Wireless Sensor Networks

    PubMed Central

    Fatima, Mehwish

    2014-01-01

    Energy efficiency is an important design paradigm in Wireless Sensor Networks (WSNs) and its consumption in dynamic environment is even more critical. Duty cycling of sensor nodes is used to address the energy consumption problem. However, along with advantages, duty cycle aware networks introduce some complexities like synchronization and latency. Due to their inherent characteristics, many traditional routing protocols show low performance in densely deployed WSNs with duty cycle awareness, when sensor nodes are supposed to have high mobility. In this paper we first present a three messages exchange Lightweight Random Walk Routing (LRWR) protocol and then evaluate its performance in WSNs for routing low data rate packets. Through NS-2 based simulations, we examine the LRWR protocol by comparing it with DYMO, a widely used WSN protocol, in both static and dynamic environments with varying duty cycles, assuming the standard IEEE 802.15.4 in lower layers. Results for the three metrics, that is, reliability, end-to-end delay, and energy consumption, show that LRWR protocol outperforms DYMO in scalability, mobility, and robustness, showing this protocol as a suitable choice in low duty cycle and dense WSNs. PMID:24696667

  12. Ad Hoc Influenza Vaccination During Years of Significant Antigenic Drift in a Tropical City With 2 Seasonal Peaks: A Cross-Sectional Survey Among Health Care Practitioners.

    PubMed

    Wong, Martin C S; Nelson, E Anthony S; Leung, Czarina; Lee, Nelson; Chan, Martin C W; Choi, Kin Wing; Rainer, Timothy H; Cheng, Frankie W T; Wong, Samuel Y S; Lai, Christopher K C; Lam, Bosco; Cheung, Tak Hong; Leung, Ting Fan; Chan, Paul K S

    2016-05-01

    We evaluated the acceptability of an additional ad hoc influenza vaccination among the health care professionals following seasons with significant antigenic drift.Self-administered, anonymous surveys were performed by hard copy questionnaires in public hospitals, and by an on-line platform available to all healthcare professionals, from April 1st to May 31st, 2015. A total of 1290 healthcare professionals completed the questionnaires, including doctors, nurses, and allied health professionals working in both the public and private systems.Only 31.8% of participating respondents expressed an intention to receive the additional vaccine, despite that the majority of them agreed or strongly agreed that it would bring benefit to the community (88.9%), save lives (86.7%), reduce medical expenses (76.3%), satisfy public expectation (82.8%), and increase awareness of vaccination (86.1%). However, a significant proportion expressed concern that the vaccine could disturb the normal immunization schedule (45.5%); felt uncertain what to do in the next vaccination round (66.0%); perceived that the summer peak might not occur (48.2%); and believed that the summer peak might not be of the same virus (83.5%). Furthermore, 27.8% of all respondents expected that the additional vaccination could weaken the efficacy of previous vaccinations; 51.3% was concerned about side effects; and 61.3% estimated that there would be a low uptake rate. If the supply of vaccine was limited, higher priority groups were considered to include the elderly aged ≥65 years with chronic medical conditions (89.2%), the elderly living in residential care homes (87.4%), and long-stay residents of institutions for the disabled (80.7%). The strongest factors associated with accepting the additional vaccine included immunization with influenza vaccines in the past 3 years, higher perceived risk of contracting influenza, and higher perceived severity of the disease impact.The acceptability to an additional ad

  13. A Routing Protocol for Multisink Wireless Sensor Networks in Underground Coalmine Tunnels

    PubMed Central

    Xia, Xu; Chen, Zhigang; Liu, Hui; Wang, Huihui; Zeng, Feng

    2016-01-01

    Traditional underground coalmine monitoring systems are mainly based on the use of wired transmission. However, when cables are damaged during an accident, it is difficult to obtain relevant data on environmental parameters and the emergency situation underground. To address this problem, the use of wireless sensor networks (WSNs) has been proposed. However, the shape of coalmine tunnels is not conducive to the deployment of WSNs as they are long and narrow. Therefore, issues with the network arise, such as extremely large energy consumption, very weak connectivity, long time delays, and a short lifetime. To solve these problems, in this study, a new routing protocol algorithm for multisink WSNs based on transmission power control is proposed. First, a transmission power control algorithm is used to negotiate the optimal communication radius and transmission power of each sink. Second, the non-uniform clustering idea is adopted to optimize the cluster head selection. Simulation results are subsequently compared to the Centroid of the Nodes in a Partition (CNP) strategy and show that the new algorithm delivers a good performance: power efficiency is increased by approximately 70%, connectivity is increased by approximately 15%, the cluster interference is diminished by approximately 50%, the network lifetime is increased by approximately 6%, and the delay is reduced with an increase in the number of sinks. PMID:27916917

  14. Evaluation of absorbent materials for use as ad hoc dry decontaminants during mass casualty incidents as part of the UK’s Initial Operational Response (IOR)

    PubMed Central

    Kassouf, Nick; Syed, Sara; Larner, Joanne; Amlôt, Richard

    2017-01-01

    The UK’s Initial Operational Response (IOR) is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A critical element of the IOR is the introduction of immediate, on-scene disrobing and decontamination of casualties to limit the adverse health effects of exposure. Ad hoc cleansing of the skin with dry absorbent materials has previously been identified as a potential means of facilitating emergency decontamination. The purpose of this study was to evaluate the in vitro oil and water absorbency of a range of materials commonly found in the domestic and clinical environments and to determine the effectiveness of a small, but representative selection of such materials in skin decontamination, using an established ex vivo model. Five contaminants were used in the study: methyl salicylate, parathion, diethyl malonate, phorate and potassium cyanide. In vitro measurements of water and oil absorbency did not correlate with ex vivo measurements of skin decontamination. When measured ex vivo, dry decontamination was consistently more effective than a standard wet decontamination method (“rinse-wipe-rinse”) for removing liquid contaminants. However, dry decontamination was ineffective against particulate contamination. Collectively, these data confirm that absorbent materials such as wound dressings and tissue paper provide an effective, generic capability for emergency removal of liquid contaminants from the skin surface, but that wet decontamination should be used for non-liquid contaminants. PMID:28152053

  15. Evaluation of absorbent materials for use as ad hoc dry decontaminants during mass casualty incidents as part of the UK's Initial Operational Response (IOR).

    PubMed

    Kassouf, Nick; Syed, Sara; Larner, Joanne; Amlôt, Richard; Chilcott, Robert P

    2017-01-01

    The UK's Initial Operational Response (IOR) is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A critical element of the IOR is the introduction of immediate, on-scene disrobing and decontamination of casualties to limit the adverse health effects of exposure. Ad hoc cleansing of the skin with dry absorbent materials has previously been identified as a potential means of facilitating emergency decontamination. The purpose of this study was to evaluate the in vitro oil and water absorbency of a range of materials commonly found in the domestic and clinical environments and to determine the effectiveness of a small, but representative selection of such materials in skin decontamination, using an established ex vivo model. Five contaminants were used in the study: methyl salicylate, parathion, diethyl malonate, phorate and potassium cyanide. In vitro measurements of water and oil absorbency did not correlate with ex vivo measurements of skin decontamination. When measured ex vivo, dry decontamination was consistently more effective than a standard wet decontamination method ("rinse-wipe-rinse") for removing liquid contaminants. However, dry decontamination was ineffective against particulate contamination. Collectively, these data confirm that absorbent materials such as wound dressings and tissue paper provide an effective, generic capability for emergency removal of liquid contaminants from the skin surface, but that wet decontamination should be used for non-liquid contaminants.

  16. Revision of the venous clinical severity score: venous outcomes consensus statement: special communication of the American Venous Forum Ad Hoc Outcomes Working Group.

    PubMed

    Vasquez, Michael A; Rabe, Eberhard; McLafferty, Robert B; Shortell, Cynthia K; Marston, William A; Gillespie, David; Meissner, Mark H; Rutherford, Robert B

    2010-11-01

    In response to the need for a disease severity measurement, the American Venous Forum committee on outcomes assessment developed the Venous Severity Scoring system in 2000. There are three components of this scoring system, the Venous Disability Score, the Venous Segmental Disease Score, and the Venous Clinical Severity Score (VCSS). The VCSS was developed from elements of the CEAP classification (clinical grade, etiology, anatomy, pathophysiology), which is the worldwide standard for describing the clinical features of chronic venous disease. However, as a descriptive instrument, the CEAP classification responds poorly to change. The VCSS was subsequently developed as an evaluative instrument that would be responsive to changes in disease severity over time and in response to treatment. Based on initial experiences with the VCSS, an international ad hoc working group of the American Venous Forum was charged with updating the instrument. This revision of the VCSS is focused on clarifying ambiguities, updating terminology, and simplifying application. The specific language of proven quality-of-life instruments was used to better address the issues of patients at the lower end of the venous disease spectrum. Periodic review and revision are necessary for generating more universal applicability and for comparing treatment outcomes in a meaningful way.

  17. An ultra-wide bandwidth-based range/GPS tight integration approach for relative positioning in vehicular ad hoc networks

    NASA Astrophysics Data System (ADS)

    Shen, Feng; Wayn Cheong, Joon; Dempster, Andrew G.

    2015-04-01

    Relative position awareness is a vital premise for the implementation of emerging intelligent transportation systems, such as collision warning. However, commercial global navigation satellite systems (GNSS) receivers do not satisfy the requirements of these applications. Fortunately, cooperative positioning (CP) techniques, through sharing the GNSS measurements between vehicles, can improve the performance of relative positioning in a vehicular ad hoc network (VANET). In this paper, while assuming there are no obstacles between vehicles, a new enhanced tightly coupled CP technique is presented by adding ultra-wide bandwidth (UWB)-based inter-vehicular range measurements. In the proposed CP method, each vehicle fuses the GPS measurements and the inter-vehicular range measurements. Based on analytical and experimental results, in the full GPS coverage environment, the new tight integration CP method outperforms the INS-aided tight CP method, tight CP method, and DGPS by 11%, 15%, and 24%, respectively; in the GPS outage scenario, the performance improvement achieves 60%, 65%, and 73%, respectively.

  18. Assessment of methods for amino acid matrix selection and their use on empirical data shows that ad hoc assumptions for choice of matrix are not justified

    PubMed Central

    Keane, Thomas M; Creevey, Christopher J; Pentony, Melissa M; Naughton, Thomas J; Mclnerney, James O

    2006-01-01

    Background In recent years, model based approaches such as maximum likelihood have become the methods of choice for constructing phylogenies. A number of authors have shown the importance of using adequate substitution models in order to produce accurate phylogenies. In the past, many empirical models of amino acid substitution have been derived using a variety of different methods and protein datasets. These matrices are normally used as surrogates, rather than deriving the maximum likelihood model from the dataset being examined. With few exceptions, selection between alternative matrices has been carried out in an ad hoc manner. Results We start by highlighting the potential dangers of arbitrarily choosing protein models by demonstrating an empirical example where a single alignment can produce two topologically different and strongly supported phylogenies using two different arbitrarily-chosen amino acid substitution models. We demonstrate that in simple simulations, statistical methods of model selection are indeed robust and likely to be useful for protein model selection. We have investigated patterns of amino acid substitution among homologous sequences from the three Domains of life and our results show that no single amino acid matrix is optimal for any of the datasets. Perhaps most interestingly, we demonstrate that for two large datasets derived from the proteobacteria and archaea, one of the most favored models in both datasets is a model that was originally derived from retroviral Pol proteins. Conclusion This demonstrates that choosing protein models based on their source or method of construction may not be appropriate. PMID:16563161

  19. Estimating HIV Incidence during Pregnancy and Knowledge of Prevention of Mother-to-Child Transmission with an Ad Hoc Analysis of Potential Cofactors

    PubMed Central

    Egbe, Thomas Obinchemti; Tazinya, Rose-Mary Asong; Halle-Ekane, Gregory Edie; Egbe, Eta-Nkongho; Achidi, Eric Akum

    2016-01-01

    Background. We determined the incidence of HIV seroconversion during the second and third trimesters of pregnancy and ad hoc potential cofactors associated with HIV seroconversion after having an HIV-negative result antenatally. We also studied knowledge of PMTCT among pregnant women in seven health facilities in Fako Division, South West Region, Cameroon. Method. During the period between September 12 and December 4, 2011, we recruited a cohort of 477 HIV-negative pregnant women by cluster sampling. Data collection was with a pretested interviewer-administered questionnaire. Sociodemographic information, knowledge of PMTCT, and methods of HIV prevention were obtained from the study population and we did Voluntary Counselling and Testing (VCT) for HIV. Results. The incidence rate of HIV seroconversion during pregnancy was 6.8/100 woman-years. Ninety percent of the participants did not use condoms throughout pregnancy but had a good knowledge of PMTCT of HIV. Only 31.9% of participants knew their HIV status before the booking visit and 33% did not know the HIV status of their partners. Conclusion. The incidence rate of HIV seroconversion in the Fako Division, Cameroon, was 6.8/100 woman-years. No risk factors associated with HIV seroconversion were identified among the study participants because of lack of power to do so. PMID:27127653

  20. A Scalable Context-Aware Objective Function (SCAOF) of Routing Protocol for Agricultural Low-Power and Lossy Networks (RPAL)

    PubMed Central

    Chen, Yibo; Chanet, Jean-Pierre; Hou, Kun-Mean; Shi, Hongling; de Sousa, Gil

    2015-01-01

    In recent years, IoT (Internet of Things) technologies have seen great advances, particularly, the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL), which provides a powerful and flexible routing framework that can be applied in a variety of application scenarios. In this context, as an important role of IoT, Wireless Sensor Networks (WSNs) can utilize RPL to design efficient routing protocols for a specific application to increase the ubiquity of networks with resource-constrained WSN nodes that are low-cost and easy to deploy. In this article, our work starts with the description of Agricultural Low-power and Lossy Networks (A-LLNs) complying with the LLN framework, and to clarify the requirements of this application-oriented routing solution. After a brief review of existing optimization techniques for RPL, our contribution is dedicated to a Scalable Context-Aware Objective Function (SCAOF) that can adapt RPL to the environmental monitoring of A-LLNs, through combining energy-aware, reliability-aware, robustness-aware and resource-aware contexts according to the composite routing metrics approach. The correct behavior of this enhanced RPL version (RPAL) was verified by performance evaluations on both simulation and field tests. The obtained experimental results confirm that SCAOF can deliver the desired advantages on network lifetime extension, and high reliability and efficiency in different simulation scenarios and hardware testbeds. PMID:26266411

  1. A Scalable Context-Aware Objective Function (SCAOF) of Routing Protocol for Agricultural Low-Power and Lossy Networks (RPAL).

    PubMed

    Chen, Yibo; Chanet, Jean-Pierre; Hou, Kun-Mean; Shi, Hongling; de Sousa, Gil

    2015-08-10

    In recent years, IoT (Internet of Things) technologies have seen great advances, particularly, the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL), which provides a powerful and flexible routing framework that can be applied in a variety of application scenarios. In this context, as an important role of IoT, Wireless Sensor Networks (WSNs) can utilize RPL to design efficient routing protocols for a specific application to increase the ubiquity of networks with resource-constrained WSN nodes that are low-cost and easy to deploy. In this article, our work starts with the description of Agricultural Low-power and Lossy Networks (A-LLNs) complying with the LLN framework, and to clarify the requirements of this application-oriented routing solution. After a brief review of existing optimization techniques for RPL, our contribution is dedicated to a Scalable Context-Aware Objective Function (SCAOF) that can adapt RPL to the environmental monitoring of A-LLNs, through combining energy-aware, reliability-aware, robustness-aware and resource-aware contexts according to the composite routing metrics approach. The correct behavior of this enhanced RPL version (RPAL) was verified by performance evaluations on both simulation and field tests. The obtained experimental results confirm that SCAOF can deliver the desired advantages on network lifetime extension, and high reliability and efficiency in different simulation scenarios and hardware testbeds.

  2. Routing to preserve energy in wireless networks

    NASA Astrophysics Data System (ADS)

    Block, Frederick J., IV

    Many applications for wireless radio networks require that some or all radios in the network rely on batteries as energy sources. In many cases, battery replacement is infeasible, expensive, or impossible. Communication protocols for such networks should be designed to preserve limited energy supplies. Because the choice of a route to a traffic sink influences how often radios must transmit and receive, poor route selection can quickly deplete the batteries of certain nodes. Previous work has shown that a network's lifetime can be extended by assigning higher routing costs to nodes with little remaining energy and nodes that must use high transmitter power to reach neighbor radios. Although using remaining energy levels in routing metrics can increase network lifetime, in practice, there may be significant error in a node's estimate of its battery level. The effect of battery level uncertainty on routing is examined. Routing metrics are presented that are designed to explicitly account for uncertainty in remaining energy. Simulation results using several statistical models for this uncertainty show that the proposed metrics perform well. In addition to knowledge of current battery levels, estimates of how quickly radios are consuming energy may be helpful in extending network lifetime. We present a family of routing metrics that incorporate a radio's rate of energy consumption. Simulation results show that the proposed family of metrics performs well under a variety of traffic models and network topologies. Route selection can also be complicated by time-varying link conditions. Radios may be subject to interference from other nearby communication systems, hostile jammers, and other, non-communication sources of noise. A route that first appears to have only a small cost may later require much greater energy expenditure when transmitting packets. Frequent route selection can help radios avoid using links with interference, but additional routing control messages

  3. Intelligent algorithms for persistent and pervasive sensing in systems comprised of wireless ad hoc networks of ground-based sensors and mobile infrastructures

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2007-04-01

    With the development of low-cost, durable unmanned aerial vehicles (UAVs), it is now practical to perform persistent sensing and target tracking autonomously over broad surveillance areas. These vehicles can sense the environment directly through onboard active sensors, or indirectly when aimed toward ground targets in a mission environment by ground-based passive sensors operating wirelessly as an ad hoc network in the environment. The combination of the swarm intelligence of the airborne infrastructure comprised of UAVs with the ant-like collaborative behavior of the unattended ground sensors creates a system capable of both persistent and pervasive sensing of mission environment, such that, the continuous collection, analysis and tracking of targets from sensor data received from the ground can be achieved. Mobile software agents are used to implement intelligent algorithms for the communications, formation control and sensor data processing in this composite configuration. The enabling mobile agents are organized in a hierarchy for the three stages of processing in the distributed system: target detection, location and recognition from the collaborative data processing among active ground-sensor nodes; transfer of the target information processed on the ground to the UAV swarm overhead; and formation control and sensor activation of the UAV swarm for sustained ground-target surveillance and tracking. Intelligent algorithms are presented that can adapt to the operation of the composite system to target dynamics and system resources. Established routines, appropriate to the processing needs of each stage, are selected as preferred based on their published use in similar scenarios, ability to be distributively implemented over the set of processors at system nodes, and ability to conserve the limited resources at the ground nodes to extend the lifetime of the pervasive network. In this paper, the performance of this distributed, collaborative system concept for

  4. Children's Pedestrian Route Selection: Efficacy of a Video and Internet Training Protocol

    PubMed Central

    Schwebel, David C.; McClure, Leslie A.

    2014-01-01

    Objective This randomized controlled trial examined one aspect of child pedestrian behavior, route selection across intersections, to evaluate whether a combination of widely-available videos and websites effectively train children in safe pedestrian route selection compared to active pedestrian safety control training and a no-contact control group. Methods A sample of 231 seven- and eight-year-olds were randomly assigned to one of four groups: training with videos and internet websites, active control groups of individualized streetside training or training within a virtual pedestrian environment, or a no-contact control group. All training groups received six 30-minute training sessions. Pedestrian route selection was assessed using two strategies, vignettes accompanied by illustrations and tabletop models of intersections, on three occasions: prior to intervention group assignment, immediately post-training, and six months after training. Results Although there were differences in route selection over time, no time by condition interaction effects were significant (ps > .05), suggesting children in the video/internet training group did not learn pedestrian route selection skills at a rate different from those in the other training groups or those in the no-contact control group. Conclusion Safe route selection is a critical component of pedestrian safety. Our results suggest children may not learn route selection from widely-available videos or websites. Explanations for the null finding and implications for both research and future practice are discussed. PMID:25170289

  5. Highly Scalable, UDP-Based Network Transport Protocols for Lambda Grids and 10 GE Routed Networks

    SciTech Connect

    PI: Robert Grossman Co-PI: Stephen Eick

    2009-08-04

    Summary of Report In work prior to this grant, NCDM developed a high performance data transport protocol called SABUL. During this grant, we refined SABUL’s functionality, and then extended both the capabilities and functionality and incorporated them into a new protocol called UDP-based Data transport Protocol, or UDT. We also began preliminary work on Composable UDT, a version of UDT that allows the user to choose among different congestion control algorithms and implement the algorithm of his choice at the time he compiles the code. Specifically, we: · Investigated the theoretical foundations of protocols similar to SABUL and UDT. · Performed design and development work of UDT, a protocol that uses UDP in both the data and control channels. · Began design and development work of Composable UDT, a protocol that supports the use of different congestion control algorithms by simply including the appropriate library when compiling the code. · Performed experimental studies using UDT and Composable UDT using real world applications such as the Sloan Digital Sky Survey (SDSS) astronomical data sets. · Released several versions of UDT and Composable, the most recent being v3.1.

  6. A decentralized fuzzy C-means-based energy-efficient routing protocol for wireless sensor networks.

    PubMed

    Alia, Osama Moh'd

    2014-01-01

    Energy conservation in wireless sensor networks (WSNs) is a vital consideration when designing wireless networking protocols. In this paper, we propose a Decentralized Fuzzy Clustering Protocol, named DCFP, which minimizes total network energy dissipation to promote maximum network lifetime. The process of constructing the infrastructure for a given WSN is performed only once at the beginning of the protocol at a base station, which remains unchanged throughout the network's lifetime. In this initial construction step, a fuzzy C-means algorithm is adopted to allocate sensor nodes into their most appropriate clusters. Subsequently, the protocol runs its rounds where each round is divided into a CH-Election phase and a Data Transmission phase. In the CH-Election phase, the election of new cluster heads is done locally in each cluster where a new multicriteria objective function is proposed to enhance the quality of elected cluster heads. In the Data Transmission phase, the sensing and data transmission from each sensor node to their respective cluster head is performed and cluster heads in turn aggregate and send the sensed data to the base station. Simulation results demonstrate that the proposed protocol improves network lifetime, data delivery, and energy consumption compared to other well-known energy-efficient protocols.

  7. Monitoring of slope-instabilities and deformations with Micro-Electro-Mechanical-Systems (MEMS) in wireless ad-hoc Sensor Networks

    NASA Astrophysics Data System (ADS)

    Arnhardt, C.; Fernández-Steeger, T. M.; Azzam, R.

    2009-04-01

    In most mountainous regions, landslides represent a major threat to human life, properties and infrastructures. Nowadays existing landslide monitoring systems are often characterized by high efforts in terms of purchase, installation, maintenance, manpower and material. In addition (or because of this) only small areas or selective points of the endangered zone can be observed by the system. Therefore the improvement of existing and the development of new monitoring and warning systems are of high relevance. The joint project "Sensor based Landslide Early Warning Systems" (SLEWS) deals with the development of a prototypic Alarm- and Early Warning system (EWS) for different types of landslides using low-cost micro-sensors (MEMS) integrated in a wireless sensor network (WSN). Modern so called Ad-Hoc, Multi-Hop wireless sensor networks (WSN) are characterized by a self organizing and self-healing capacity of the system (autonomous systems). The network consists of numerous individual and own energy-supply operating sensor nodes, that can send data packages from their measuring devices (here: MEMS) over other nodes (Multi-Hop) to a collection point (gateway). The gateway provides the interface to central processing and data retrieval units (PC, Laptop or server) outside the network. In order to detect and monitor the different landslide processes (like fall, topple, spreading or sliding) 3D MEMS capacitive sensors made from single silicon crystals and glass were chosen to measure acceleration, tilting and altitude changes. Based on the so called MEMS (Micro-Electro-Mechanical Systems) technology, the sensors combine very small mechanical and electronic units, sensing elements and transducers on a small microchip. The mass production of such type of sensors allows low cost applications in different areas (like automobile industries, medicine, and automation technology). Apart from the small and so space saving size and the low costs another advantage is the energy

  8. VANET Broadcast Protocol Based on Fuzzy Logic and Lightweight Retransmission Mechanism

    NASA Astrophysics Data System (ADS)

    Wu, Celimuge; Ohzahata, Satoshi; Kato, Toshihiko

    Vehicular ad hoc networks have been attracting the interest of both academic and industrial communities on account of their potential role in Intelligent Transportation Systems (ITS). However, due to vehicle movement and fading in wireless communications, providing a reliable and efficient multi-hop broadcast service in vehicular ad hoc networks is still an open research topic. In this paper, we propose FUZZBR (FUZZy BRoadcast), a fuzzy logic based multi-hop broadcast protocol for information dissemination in vehicular ad hoc networks. FUZZBR has low message overhead since it uses only a subset of neighbor nodes to relay data messages. In the relay node selection, FUZZBR jointly considers multiple metrics of inter-vehicle distance, node mobility and signal strength by employing the fuzzy logic. FUZZBR also uses a lightweight retransmission mechanism to retransmit a packet when a relay fails. We use computer simulations to evaluate the performance of FUZZBR.

  9. Traffic dynamics based on local routing protocol on a scale-free network.

    PubMed

    Wang, Wen-Xu; Wang, Bing-Hong; Yin, Chuan-Yang; Xie, Yan-Bo; Zhou, Tao

    2006-02-01

    We propose a packet routing strategy with a tunable parameter based on the local structural information of a scale-free network. As free traffic flow on the communication networks is key to their normal and efficient functioning, we focus on the network capacity that can be measured by the critical point of phase transition from free flow to congestion. Simulations show that the maximal capacity corresponds to alpha= -1 in the case of identical nodes' delivering ability. To explain this, we investigate the number of packets of each node depending on its degree in the free flow state and observe the power law behavior. Other dynamic properties including average packets traveling time and traffic load are also studied. Inspiringly, our results indicate that some fundamental relationships exist between the dynamics of synchronization and traffic on the scale-free networks.

  10. Efficient and Stable Routing Algorithm Based on User Mobility and Node Density in Urban Vehicular Network

    PubMed Central

    Al-Mayouf, Yusor Rafid Bahar; Ismail, Mahamod; Abdullah, Nor Fadzilah; Wahab, Ainuddin Wahid Abdul; Mahdi, Omar Adil; Khan, Suleman; Choo, Kim-Kwang Raymond

    2016-01-01

    Vehicular ad hoc networks (VANETs) are considered an emerging technology in the industrial and educational fields. This technology is essential in the deployment of the intelligent transportation system, which is targeted to improve safety and efficiency of traffic. The implementation of VANETs can be effectively executed by transmitting data among vehicles with the use of multiple hops. However, the intrinsic characteristics of VANETs, such as its dynamic network topology and intermittent connectivity, limit data delivery. One particular challenge of this network is the possibility that the contributing node may only remain in the network for a limited time. Hence, to prevent data loss from that node, the information must reach the destination node via multi-hop routing techniques. An appropriate, efficient, and stable routing algorithm must be developed for various VANET applications to address the issues of dynamic topology and intermittent connectivity. Therefore, this paper proposes a novel routing algorithm called efficient and stable routing algorithm based on user mobility and node density (ESRA-MD). The proposed algorithm can adapt to significant changes that may occur in the urban vehicular environment. This algorithm works by selecting an optimal route on the basis of hop count and link duration for delivering data from source to destination, thereby satisfying various quality of service considerations. The validity of the proposed algorithm is investigated by its comparison with ARP-QD protocol, which works on the mechanism of optimal route finding in VANETs in urban environments. Simulation results reveal that the proposed ESRA-MD algorithm shows remarkable improvement in terms of delivery ratio, delivery delay, and communication overhead. PMID:27855165

  11. Efficient and Stable Routing Algorithm Based on User Mobility and Node Density in Urban Vehicular Network.

    PubMed

    Al-Mayouf, Yusor Rafid Bahar; Ismail, Mahamod; Abdullah, Nor Fadzilah; Wahab, Ainuddin Wahid Abdul; Mahdi, Omar Adil; Khan, Suleman; Choo, Kim-Kwang Raymond

    2016-01-01

    Vehicular ad hoc networks (VANETs) are considered an emerging technology in the industrial and educational fields. This technology is essential in the deployment of the intelligent transportation system, which is targeted to improve safety and efficiency of traffic. The implementation of VANETs can be effectively executed by transmitting data among vehicles with the use of multiple hops. However, the intrinsic characteristics of VANETs, such as its dynamic network topology and intermittent connectivity, limit data delivery. One particular challenge of this network is the possibility that the contributing node may only remain in the network for a limited time. Hence, to prevent data loss from that node, the information must reach the destination node via multi-hop routing techniques. An appropriate, efficient, and stable routing algorithm must be developed for various VANET applications to address the issues of dynamic topology and intermittent connectivity. Therefore, this paper proposes a novel routing algorithm called efficient and stable routing algorithm based on user mobility and node density (ESRA-MD). The proposed algorithm can adapt to significant changes that may occur in the urban vehicular environment. This algorithm works by selecting an optimal route on the basis of hop count and link duration for delivering data from source to destination, thereby satisfying various quality of service considerations. The validity of the proposed algorithm is investigated by its comparison with ARP-QD protocol, which works on the mechanism of optimal route finding in VANETs in urban environments. Simulation results reveal that the proposed ESRA-MD algorithm shows remarkable improvement in terms of delivery ratio, delivery delay, and communication overhead.

  12. Routing Based on Length of Time of Available Connection

    NASA Technical Reports Server (NTRS)

    Anandappan, Thanga (Inventor); Roy, Aloke (Inventor); Malve, Sharath Babu (Inventor); Toth, Louis T. (Inventor)

    2016-01-01

    In an embodiment, a method of routing packets at a first node in an ad-hoc network is provided. The method includes receiving, at the first node, a plurality of route-alive messages corresponding to a destination, each of the plurality of route-alive messages including a route time indicating a length of time in which a communicative connection is available between the second node that sent the respective route-alive message and the destination. The method also includes determining an updated route time for each second node. The updated route time corresponds to a length of time in which a communication connection is available between the first node and the destination through the respective second node. A second node is selected for sending a packet to based on the updated route time for each of the second nodes, wherein a node having a longer updated route time is given higher priority for selection.

  13. An Evidence-Based Unified Definition of Lifelong and Acquired Premature Ejaculation: Report of the Second International Society for Sexual Medicine Ad Hoc Committee for the Definition of Premature Ejaculation

    PubMed Central

    Serefoglu, Ege Can; McMahon, Chris G; Waldinger, Marcel D; Althof, Stanley E; Shindel, Alan; Adaikan, Ganesh; Becher, Edgardo F; Dean, John; Giuliano, Francois; Hellstrom, Wayne JG; Giraldi, Annamaria; Glina, Sidney; Incrocci, Luca; Jannini, Emmanuele; McCabe, Marita; Parish, Sharon; Rowland, David; Segraves, R Taylor; Sharlip, Ira; Torres, Luiz Otavio

    2014-01-01

    Introduction The International Society for Sexual Medicine (ISSM) Ad Hoc Committee for the Definition of Premature Ejaculation developed the first evidence-based definition for lifelong premature ejaculation (PE) in 2007 and concluded that there were insufficient published objective data at that time to develop a definition for acquired PE. Aim The aim of this article is to review and critique the current literature and develop a contemporary, evidence-based definition for acquired PE and/or a unified definition for both lifelong and acquired PE. Methods In April 2013, the ISSM convened a second Ad Hoc Committee for the Definition of Premature Ejaculation in Bangalore, India. The same evidence-based systematic approach to literature search, retrieval, and evaluation used by the original committee was adopted. Results The committee unanimously agreed that men with lifelong and acquired PE appear to share the dimensions of short ejaculatory latency, reduced or absent perceived ejaculatory control, and the presence of negative personal consequences. Men with acquired PE are older, have higher incidences of erectile dysfunction, comorbid disease, and cardiovascular risk factors, and have a longer intravaginal ejaculation latency time (IELT) as compared with men with lifelong PE. A self-estimated or stopwatch IELT of 3 minutes was identified as a valid IELT cut-off for diagnosing acquired PE. On this basis, the committee agreed on a unified definition of both acquired and lifelong PE as a male sexual dysfunction characterized by (i) ejaculation that always or nearly always occurs prior to or within about 1 minute of vaginal penetration from the first sexual experience (lifelong PE) or a clinically significant and bothersome reduction in latency time, often to about 3 minutes or less (acquired PE); (ii) the inability to delay ejaculation on all or nearly all vaginal penetrations; and (iii) negative personal consequences, such as distress, bother, frustration, and/or the

  14. Space-Data Routers: Advanced data routing protocols for enhancing data exploitation for space weather applications

    NASA Astrophysics Data System (ADS)

    Anastasiadis, Anastasios; Daglis, Ioannis A.; Balasis, George; Papadimitriou, Constantinos; Tsaoussidis, Vassilios; Diamantopoulos, Sotirios

    2014-05-01

    Data sharing and access are major issues in space sciences, as they influence the degree of data exploitation. The availability of multi-spacecraft distributed observation methods and adaptive mission architectures require computationally intensive analysis methods. Moreover, accurate space weather forecasting and future space exploration far from Earth will be in need of real-time data distribution and assimilation technologies. The FP7-Space collaborative research project "Space-Data Routers" (SDR) relies on space internetworking and in particular on Delay Tolerant Networking (DTN), which marks the new era in space communications. SDR unifies space and earth communication infrastructures and delivers a set of tools and protocols for space-data exploitation. The main goal is to allow space agencies, academic institutes and research centers to share space-data generated by single or multiple missions, in an efficient, secure and automated manner. Here we are presenting the architecture and basic functionality of a DTN-based application specifically designed in the framework of the SDR project, for data query, retrieval and administration that will enable addressing outstanding science questions related to space weather, through the provision of simultaneous real-time data sampling at multiple points in space. The work leading to this paper has received funding from the European Union's Seventh Framework Programme (FP7-SPACE-2010-1) under grant agreement no. 263330 for the SDR (Space-Data Routers for Exploiting Space Data) collaborative research project. This paper reflects only the authors' views and the Union is not liable for any use that may be made of the information contained therein.

  15. A Comparative experimental study of media access protocols for wireless radio networks

    SciTech Connect

    Barrett, C. L.; Drozda, M.; Marathe, M. V.

    2001-05-24

    We conduct a comparative experimental analysis of three well known media access protocols: 802.11, CSMA, and MACA for wireless radio networks. Both fixed and ad-hoc networks are considered. The experimental analysis was carried out using GloMoSim: a tool for simulating wireless networks. The main focus of experiments was to study how (i) the size of the network, (ii) number of open connections, (iii) the spatial location of individual connections, (iv) speed with which individual nodes move and (v) protocols higher up in the protocol stack (e,g. routing layer) affect the performance of the media access sublayer protocols. The performance of the protocols was measured w.r.t. three important parameters: (1) number of received packets, (2) average latency of each packet, and (3) throughput. The following general qualitative conclusions were obtained; some of the conclusions reinforce the earlier claims by other researchers. (1) Although 802.11 performs better than the other two protocols with respect to fairness of transmission, packets dropped, and latency, its performance is found to (i) show a lot of variance with changing input parameters and (ii) the overall performance still leaves a lot of room for improvement. (2) CSMA does not perform too well under the fairness criteria, however, was the best in terms of the latency criteria. (3) MACA also shows fairness problems and has poor performance at high packet injection rates. (4) Protocols in the higher level of the protocol stack affect the MAC layer performance. The main general implications of our work is two folds: (1) No single protocol dominated the other protocols across various measures of efficiency. This motivates the design of a new class of parameterized protocols that adapt to changes in the network connectivity and loads. We refer to these class of protocols as parameterized dynamically adaptive efficient protocols and as a first step suggest key design requirements for such a class of protocols. (2

  16. On Alarm Protocol in Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Cichoń, Jacek; Kapelko, Rafał; Lemiesz, Jakub; Zawada, Marcin

    We consider the problem of efficient alarm protocol for ad-hoc radio networks consisting of devices that try to gain access for transmission through a shared radio communication channel. The problem arise in tasks that sensors have to quickly inform the target user about an alert situation such as presence of fire, dangerous radiation, seismic vibrations, and more. In this paper, we present a protocol which uses O(logn) time slots and show that Ω(logn/loglogn) is a lower bound for used time slots.

  17. Effective Protocols for Mobile Communications and Networking

    SciTech Connect

    Espinoza, J.; Sholander, P.; Van Leeuwen, B,

    1998-12-01

    This report examines methods of mobile communications with an emphasis on mobile computing and wireless communications. Many of the advances in communications involve the use of Internet Protocol (IP), Asynchronous Transfer Mode (ATM), and ad hoc network protocols. However, many of the advances in these protocols have been focused on wired communications. Recently much focus has been directed at advancing communication technology in the area of mobile wireless networks. This report discusses various protocols used in mobile communications and proposes a number of extensions to existing protocols. A detailed discussion is also included on desirable protocol characteristics and evaluation criteria. In addition, the report includes a discussion on several network simulation tools that maybe used to evaluate network protocols.

  18. The Traffic Adaptive Data Dissemination (TrAD) Protocol for both Urban and Highway Scenarios.

    PubMed

    Tian, Bin; Hou, Kun Mean; Zhou, Haiying

    2016-06-21

    The worldwide economic cost of road crashes and injuries is estimated to be US$518 billion per year and the annual congestion cost in France is estimated to be €5.9 billion. Vehicular Ad hoc Networks (VANETs) are one solution to improve transport features such as traffic safety, traffic jam and infotainment on wheels, where a great number of event-driven messages need to be disseminated in a timely way in a region of interest. In comparison with traditional wireless networks, VANETs have to consider the highly dynamic network topology and lossy links due to node mobility. Inter-Vehicle Communication (IVC) protocols are the keystone of VANETs. According to our survey, most of the proposed IVC protocols focus on either highway or urban scenarios, but not on both. Furthermore, too few protocols, considering both scenarios, can achieve high performance. In this paper, an infrastructure-less Traffic Adaptive data Dissemination (TrAD) protocol which takes into account road traffic and network traffic status for both highway and urban scenarios will be presented. TrAD has double broadcast suppression techniques and is designed to adapt efficiently to the irregular road topology. The performance of the TrAD protocol was evaluated quantitatively by means of realistic simulations taking into account different real road maps, traffic routes and vehicular densities. The obtained simulation results show that TrAD is more efficient in terms of packet delivery ratio, number of transmissions and delay in comparison with the performance of three well-known reference protocols. Moreover, TrAD can also tolerate a reasonable degree of GPS drift and still achieve efficient data dissemination.

  19. The Traffic Adaptive Data Dissemination (TrAD) Protocol for both Urban and Highway Scenarios

    PubMed Central

    Tian, Bin; Hou, Kun Mean; Zhou, Haiying

    2016-01-01

    The worldwide economic cost of road crashes and injuries is estimated to be US$518 billion per year and the annual congestion cost in France is estimated to be €5.9 billion. Vehicular Ad hoc Networks (VANETs) are one solution to improve transport features such as traffic safety, traffic jam and infotainment on wheels, where a great number of event-driven messages need to be disseminated in a timely way in a region of interest. In comparison with traditional wireless networks, VANETs have to consider the highly dynamic network topology and lossy links due to node mobility. Inter-Vehicle Communication (IVC) protocols are the keystone of VANETs. According to our survey, most of the proposed IVC protocols focus on either highway or urban scenarios, but not on both. Furthermore, too few protocols, considering both scenarios, can achieve high performance. In this paper, an infrastructure-less Traffic Adaptive data Dissemination (TrAD) protocol which takes into account road traffic and network traffic status for both highway and urban scenarios will be presented. TrAD has double broadcast suppression techniques and is designed to adapt efficiently to the irregular road topology. The performance of the TrAD protocol was evaluated quantitatively by means of realistic simulations taking into account different real road maps, traffic routes and vehicular densities. The obtained simulation results show that TrAD is more efficient in terms of packet delivery ratio, number of transmissions and delay in comparison with the performance of three well-known reference protocols. Moreover, TrAD can also tolerate a reasonable degree of GPS drift and still achieve efficient data dissemination. PMID:27338393

  20. Hearings before the Ad Hoc Committee on Maritime Education and Training of the Committee on Merchant Marine and Fisheries, Ninety-Third Congress; Second Session on Officer Requirements, and Session on Maritime Education Regarding Safety at Sea. Serial No. 93-44.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Committee on Merchant Marine and Fisheries.

    The publication consists of Congressional hearings before the Ad Hoc Committee on Maritime Education and Training: (1) June 26, 1974 hearing pertaining to officer requirements and (2) November 19, 1974 hearing on maritime education regarding safety at sea. Estimated cost per graduate for the U. S. Merchant Marine 1973 class was $31,100. Supply and…

  1. [Multimodal pain therapy for treatment of chronic pain syndrome. Consensus paper of the ad hoc commission on multimodal interdisciplinary pain management of the German Pain Society on treatment contents].

    PubMed

    Arnold, B; Brinkschmidt, T; Casser, H-R; Diezemann, A; Gralow, I; Irnich, D; Kaiser, U; Klasen, B; Klimczyk, K; Lutz, J; Nagel, B; Pfingsten, M; Sabatowski, R; Schesser, R; Schiltenwolf, M; Seeger, D; Söllner, W

    2014-10-01

    Multimodal pain management is a comprehensive treatment of complex chronic pain syndromes. In addition to medical therapy various other specialized therapeutic interventions based on the biopsychosocial model of pain origin and chronic pain development, are added. During the last few years treatment centers for chronic pain have been established throughout Germany. Multimodal pain management has been included in the official catalogue of the recognized medical procedures for day clinic units as well as for inpatient pain management. In daily practice there is, however, still a lack of clarity and of consistency about the components that multimodal pain management should contain. This is the reason for the ad hoc commission on multimodal interdisciplinary pain management of the German Pain Society to propose the following position paper that has been worked out in a multilevel and interdisciplinary consensus process. The paper describes the mandatory treatment measures in the four core disciplines of multimodal pain management, pain medicine, psychotherapy, exercise therapy including physiotherapy and assistant medical professions including nurses.

  2. Criteria for the diagnosis of heat-related deaths: National Association of Medical Examiners. Position paper. National Association of Medical Examiners Ad Hoc Committee on the Definition of Heat-Related Fatalities.

    PubMed

    Donoghue, E R; Graham, M A; Jentzen, J M; Lifschultz, B D; Luke, J L; Mirchandani, H G

    1997-03-01

    The National Association of Medical Examiners Ad Hoc Committee on the Definition of Heat-Related Fatalities recommends the following definition of "heat-related death": a death in which exposure to high ambient temperature either caused the death or significantly contributed to it. The committee also recommends that the diagnosis of heat-related death be based on a history of exposure to high ambient temperature and the reasonable exclusion of other causes of hyperthermia. The diagnosis may be established from the circumstances surrounding the death, investigative reports concerning environmental temperature, and/or measured antemortem body temperature at the time of collapse. In cases where the measured antemortem body temperature at the time of collapse was > or = 105 degrees F (> or = 40.6 degrees C), the cause of death should be certified as heat stroke or hyperthermia. Deaths may also be certified as heat stroke or hyperthermia with lower body temperatures when cooling has been attempted prior to arrival at the hospital and/or when there is a clinical history of mental status changes and elevated liver and muscle enzymes. In cases where the antemortem body temperature cannot be established but the environmental temperature at the time of collapse was high, an appropriate heat-related diagnosis should be listed as the cause of death or as a significant contributing condition.

  3. [Health evaluation of trichloroethylene in indoor air : communication from the German ad-hoc working group on indoor guidelines of the Indoor Air Hygiene Committee and of the states' supreme health authorities].

    PubMed

    2015-07-01

    In the European Hazardous Substances Regulation No 1272/2008 trichloroethylene has been classified as a probable human carcinogen and a suspected mutagen. According to several Committees (German Committee on Hazardous Substances, European Scientific Committee on Occupational Exposure Limits, European Chemicals Agency´s Committee for Risk Assessment (ECHA-RAC)) concentrations of trichloroethylene cytotoxic to renal tubuli may increase the risk to develop renal cancer. At non-cytotoxic concentrations of trichloroethylene a much lower cancer risk may be assumed. Therefore, evaluating the cancer risk to the public following inhalation of trichloroethylene ECHA-RAC has assumed a sublinear exposure-response relationship for carcinogenicity of trichloroethylene. Specifically, ECHA-RAC assessed a cancer risk of 6.4 × 10(- 5) (mg/m(3))(- 1) following life time exposure to trichloroethylene below a NOAEC for renal cytotoxicity of 6 mg trichloroethylene/m(3). Further evaluation yields a life-time risk of 10(- 6) corresponding to 0.02 mg trichloroethylene/m(3). This concentration is well above the reference (e.g. background) concentration of trichloroethylene in indoor air. Consequently the Ad-hoc Working Group on Indoor Guidelines recommends 0.02 mg trichloroethylene/m(3) as a risk-related guideline for indoor air. Measures to reduce exposure are considered inappropriate at concentrations below this guideline.

  4. [Indoor air guide values for acetaldehyde. Announcement of the German Ad-hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and of the States' Supreme Health Authorities].

    PubMed

    2013-10-01

    The German Ad-hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and the States' Supreme Health Authorities is issuing indoor air guide values to protect public health. No suitable human studies are available for health evaluation of acetaldehyde in indoor air. In a well-documented subchronic inhalation animal study with rats assessed as reliable, local irritation effects were observed in nasal epithelia, most prominently in the olfactory epithelium with loss of olfactory neuronal cells. This study leads to a LOAEC of 48 mg acetaldehyde/m3 for continuous exposure for the endpoint nasal epithelium degeneration. By applying an interspecies factor of 1, a factor of 10 for interindividual variability, and a factor of 2 to account for the higher respiratory rate of children compared to adults, a health hazard guide value (RW II) of 1 mg acetaldehyde/m3 is obtained. A health precaution guide value (RW I) of 0.1 mg acetaldehyde/m3 is recommended.

  5. Ad-Hoc Implicature in Preschool Children

    ERIC Educational Resources Information Center

    Stiller, Alex J.; Goodman, Noah D.; Frank, Michael C.

    2015-01-01

    If a speaker tells us that "some guests were late to the party," we typically infer that not all were. Implicatures, in which an ambiguous statement ("some and possibly all") is strengthened pragmatically (to "some and not all"), are a paradigm case of pragmatic reasoning. Inferences of this sort are difficult for…

  6. Swift Trust in Distributed Ad Hoc Teams

    DTIC Science & Technology

    2007-10-04

    team at risk. Questionnaires assessed the impact of regimental identity and potential trust violations on levels of team trust before the mission...personnellement. Cette notion est de plus en plus utilisée dans les ouvrages spécialisés pour expliquer comment les membres des équipes spéciales... questionnaires distribués aux participants ont permis d’évaluer l’impact de l’identité régimentaire et des abus de confiance sur le niveau de confiance

  7. Life Cycles of Ad Hoc Task Groups

    DTIC Science & Technology

    1983-10-01

    internal group dynamics, and external influence on the group . Time pressure . Members’ first comments about time pressure appeared at transition meetings...organizational supports and management behavior can influence team effectiveness. Yet it is unclear how such factors may affect the group "_.3...on members’ ability to work together, yet little is known about how the gradual creation of work products influences groups ’ social development. The

  8. DAWN: Dynamic Ad-hoc Wireless Network

    DTIC Science & Technology

    2016-06-19

    none) (c) Presentations 03/15/2007 03/15/2007 27.00 28.00 Received Paper Ning Li, Jennifer C. Hou. A Scalable, Power-Efficient Broadcast Algorithm for...Wireless Networks, , ( ): . doi: Ning Li, Jennifer C. Hou. Localized Topology Control Algorithms for Heterogeneous Wireless Networks, IEEE

  9. Mobile Ad Hoc Network Emulation Environment

    DTIC Science & Technology

    2009-10-01

    and debugging information in both real-time and post-test-run playback modes. Display characteristics are controlled by the test nodes, which pass...2007. MILCOM 2007. IEEE , vol., no., pp.I-6, 29-31 Oct. 2007. [IS] http ://cs.itd.nrl.navy.mil /work/rapr/index, php [16] http ://www.alionscience.com

  10. [Guide values for 1-butanol in indoor air. Report of the German Ad Hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and of the States' Supreme Health Authorities].

    PubMed

    2014-06-01

    The German Ad Hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and the States' Supreme Health Authorities is issuing indoor air guide values to protect public health. No human studies of sufficient quality are available for the evaluation of 1-butanol in indoor air. In a well-documented oral study on reproduction toxicity in rats, assessed as reliable, impairment of embryo development was observed. Benchmark modeling of the study data by US-EPA revealed a BMDL10 of 26.1 mg/kg b.w. per day. The working group used this BMDL10 as the point of departure for the derivation of the guide value II. Considering a human respiration rate of 20 m(3) per day and a human body weight of 70 kg, this dose was converted into an inhalative concentration. Applying a factor of 0.6 to account for the inhalative absorption rate, an allometric extrapolation factor from rat to human (factor 4), an interspecies factor of 2.5 for toxicodynamics, and a factor of 10 to account for individual differences (intraspecies factor), results in a health hazard guide value (RW II) of 2 mg 1-butanol/m(3). The benchmark dose calculation of the same study generated a BMDL05 of 12.4 mg/kg b.w. per day. Applying the same assessment factors as for RW II, a precautionary guide value (RW I) of 0.7 mg 1-butanol/m(3) indoor air is calculated.

  11. On Designing Thermal-Aware Localized QoS Routing Protocol for in-vivo Sensor Nodes in Wireless Body Area Networks

    PubMed Central

    Monowar, Muhammad Mostafa; Bajaber, Fuad

    2015-01-01

    In this paper, we address the thermal rise and Quality-of-Service (QoS) provisioning issue for an intra-body Wireless Body Area Network (WBAN) having in-vivo sensor nodes. We propose a thermal-aware QoS routing protocol, called TLQoS, that facilitates the system in achieving desired QoS in terms of delay and reliability for diverse traffic types, as well as avoids the formation of highly heated nodes known as hotspot(s), and keeps the temperature rise along the network to an acceptable level. TLQoS exploits modular architecture wherein different modules perform integrated operations in providing multiple QoS service with lower temperature rise. To address the challenges of highly dynamic wireless environment inside the human body. TLQoS implements potential-based localized routing that requires only local neighborhood information. TLQoS avoids routing loop formation as well as reduces the number of hop traversal exploiting hybrid potential, and tuning a configurable parameter. We perform extensive simulations of TLQoS, and the results show that TLQoS has significant performance improvements over state-of-the-art approaches. PMID:26083228

  12. Reducing Communication Detection and Eavesdropping using Mobile Agent Relay Networks

    DTIC Science & Technology

    2010-12-01

    to maintain a wireless network to support the users. This type of solution is often used in Mobile Ad Hoc Networking (MANET) ( Corson 1999). MANET...USA: IEEE Computer Society. Corson , S. 1999. Mobile Ad hoc Networking (MANET): Routing Protocol Performance Issues and Evaluation Considerations. RFC

  13. Synthesizing Existing CSMA and TDMA Based MAC Protocols for VANETs

    PubMed Central

    Huang, Jiawei; Li, Qi; Zhong, Shaohua; Liu, Lianhai; Zhong, Ping; Wang, Jianxin; Ye, Jin

    2017-01-01

    Many Carrier Sense Multiple Access (CSMA) and Time Division Multiple Access (TDMA) based medium access control (MAC) protocols for vehicular ad hoc networks (VANETs) have been proposed recently. Contrary to the common perception that they are competitors, we argue that the underlying strategies used in these MAC protocols are complementary. Based on this insight, we design CTMAC, a MAC protocol that synthesizes existing strategies; namely, random accessing channel (used in CSMA-style protocols) and arbitral reserving channel (used in TDMA-based protocols). CTMAC swiftly changes its strategy according to the vehicle density, and its performance is better than the state-of-the-art protocols. We evaluate CTMAC using at-scale simulations. Our results show that CTMAC reduces the channel completion time and increases the network goodput by 45% for a wide range of application workloads and network settings. PMID:28208590

  14. Synthesizing Existing CSMA and TDMA Based MAC Protocols for VANETs.

    PubMed

    Huang, Jiawei; Li, Qi; Zhong, Shaohua; Liu, Lianhai; Zhong, Ping; Wang, Jianxin; Ye, Jin

    2017-02-10

    Many Carrier Sense Multiple Access (CSMA) and Time Division Multiple Access (TDMA) based medium access control (MAC) protocols for vehicular ad hoc networks (VANETs) have been proposed recently. Contrary to the common perception that they are competitors, we argue that the underlying strategies used in these MAC protocols are complementary. Based on this insight, we design CTMAC, a MAC protocol that synthesizes existing strategies; namely, random accessing channel (used in CSMA-style protocols) and arbitral reserving channel (used in TDMA-based protocols). CTMAC swiftly changes its strategy according to the vehicle density, and its performance is better than the state-of-the-art protocols. We evaluate CTMAC using at-scale simulations. Our results show that CTMAC reduces the channel completion time and increases the network goodput by 45% for a wide range of application workloads and network settings.

  15. A novel end-to-end fault detection and localization protocol for wavelength-routed WDM networks

    NASA Astrophysics Data System (ADS)

    Zeng, Hongqing; Vukovic, Alex; Huang, Changcheng

    2005-09-01

    Recently the wavelength division multiplexing (WDM) networks are becoming prevalent for telecommunication networks. However, even a very short disruption of service caused by network faults may lead to high data loss in such networks due to the high date rates, increased wavelength numbers and density. Therefore, the network survivability is critical and has been intensively studied, where fault detection and localization is the vital part but has received disproportional attentions. In this paper we describe and analyze an end-to-end lightpath fault detection scheme in data plane with the fault notification in control plane. The endeavor is focused on reducing the fault detection time. In this protocol, the source node of each lightpath keeps sending hello packets to the destination node exactly following the path for data traffic. The destination node generates an alarm once a certain number of consecutive hello packets are missed within a given time period. Then the network management unit collects all alarms and locates the faulty source based on the network topology, as well as sends fault notification messages via control plane to either the source node or all upstream nodes along the lightpath. The performance evaluation shows such a protocol can achieve fast fault detection, and at the same time, the overhead brought to the user data by hello packets is negligible.

  16. Nutritional route in oesophageal resection trial II (NUTRIENT II): study protocol for a multicentre open-label randomised controlled trial

    PubMed Central

    Berkelmans, Gijs H K; Wilts, Bas J W; Kouwenhoven, Ewout A; Kumagai, Koshi; Nilsson, Magnus; Weijs, Teus J; Nieuwenhuijzen, Grard A P; van Det, Marc J; Luyer, Misha D P

    2016-01-01

    Introduction Early start of an oral diet is safe and beneficial in most types of gastrointestinal surgery and is a crucial part of fast track or enhanced recovery protocols. However, the feasibility and safety of oral intake directly following oesophagectomy remain unclear. The aim of this study is to investigate the effects of early versus delayed start of oral intake on postoperative recovery following oesophagectomy. Methods and analysis This is an open-label multicentre randomised controlled trial. Patients undergoing elective minimally invasive or hybrid oesophagectomy for cancer are eligible. Further inclusion criteria are intrathoracic anastomosis, written informed consent and age 18 years or older. Inability for oral intake, inability to place a feeding jejunostomy, inability to provide written consent, swallowing disorder, achalasia, Karnofsky Performance Status <80 and malnutrition are exclusion criteria. Patients will be randomised using online randomisation software. The intervention group (direct oral feeding) will receive a liquid oral diet for 2 weeks with gradually expanding daily maximums. The control group (delayed oral feeding) will receive enteral feeding via a jejunostomy during 5 days and then start the same liquid oral diet. The primary outcome measure is functional recovery. Secondary outcome measures are 30-day surgical complications; nutritional status; need for artificial nutrition; need for additional interventions; health-related quality of life. We aim to recruit 148 patients. Statistical analysis will be performed according to an intention to treat principle. Results are presented as risk ratios with corresponding 95% CIs. A two-tailed p<0.05 is considered statistically significant. Ethics and dissemination Our study protocol has received ethical approval from the Medical research Ethics Committees United (MEC-U). This study is conducted according to the principles of Good Clinical Practice. Verbal and written informed consent is

  17. A Signcryption based Light Weight Key Exchange Protocol

    NASA Astrophysics Data System (ADS)

    Feng, Yong; Wei, Qian; Zhang, Xing

    Traditional cryptography based authenticated Diffie-Hellman key exchange protocols expose the problems of efficiency and privacy since signature-then-encryption is heavy to wireless communication special for flexible dynamic deployment, i.e., wireless mesh networks, wireless sensor networks, mobile ad hoc networks, etc., in computational cost and communicational overhead and traditional digital signature allows anyone to verify its validity using the corresponding public key. In this paper, we propose a signcryption based light weight key exchange protocol named SLWKE which can provide resistance to traditional attacks, i.e., eavesdropping, deducing, replaying, interleaving, forging and repudiating, and unknown key-share attack and save computational cost by three modular calculations, i.e., one modular inversion, one modular addition and one modular multiplicative, included in a signature s and communicational overhead by secure length of IqI in comparison to signcryption based direct key exchange using a time-stamp protocol termed Dkeuts.

  18. Self-Organized Link State Aware Routing for Multiple Mobile Agents in Wireless Network

    NASA Astrophysics Data System (ADS)

    Oda, Akihiro; Nishi, Hiroaki

    Recently, the importance of data sharing structures in autonomous distributed networks has been increasing. A wireless sensor network is used for managing distributed data. This type of distributed network requires effective information exchanging methods for data sharing. To reduce the traffic of broadcasted messages, reduction of the amount of redundant information is indispensable. In order to reduce packet loss in mobile ad-hoc networks, QoS-sensitive routing algorithm have been frequently discussed. The topology of a wireless network is likely to change frequently according to the movement of mobile nodes, radio disturbance, or fading due to the continuous changes in the environment. Therefore, a packet routing algorithm should guarantee QoS by using some quality indicators of the wireless network. In this paper, a novel information exchanging algorithm developed using a hash function and a Boolean operation is proposed. This algorithm achieves efficient information exchanges by reducing the overhead of broadcasting messages, and it can guarantee QoS in a wireless network environment. It can be applied to a routing algorithm in a mobile ad-hoc network. In the proposed routing algorithm, a routing table is constructed by using the received signal strength indicator (RSSI), and the neighborhood information is periodically broadcasted depending on this table. The proposed hash-based routing entry management by using an extended MAC address can eliminate the overhead of message flooding. An analysis of the collision of hash values contributes to the determination of the length of the hash values, which is minimally required. Based on the verification of a mathematical theory, an optimum hash function for determining the length of hash values can be given. Simulations are carried out to evaluate the effectiveness of the proposed algorithm and to validate the theory in a general wireless network routing algorithm.

  19. Making MANET secured against malicious attack

    NASA Astrophysics Data System (ADS)

    Kush, Ashwani; Taneja, Sunil; Kush, Shagun

    2011-12-01

    A Mobile Adhoc Network (MANET) is characterized by mobile nodes, multihop wireless connectivity, infrastructureless environment and dynamic topology. A recent trend in Ad Hoc network routing is the reactive ondemand philosophy where routes are established only when required. Stable Routing is of major concern in Ad hoc routing. Security and Power efficiency are the major concerns in this field. This paper is an effort to use security to achieve more reliable routing. The ad hoc environment is accessible to both legitimate network users and malicious attackers. The proposed scheme is intended to incorporate security aspect on existing protocols. The study will help in making protocol more robust against attacks to achieve stable routing in routing protocols.

  20. Reliable Internet Routing

    DTIC Science & Technology

    2011-09-01

    constraints [38]), and the destination of the packet (as needed for blackholing , motivated by security or politics). In particular, we admit as “typical...reducing convergence time, or adding mech- anisms to detect transient loops and blackholes , we avoid dynamic routing protocols entirely [18]. Our...solution can significantly reduce the occurrence of route blackholing and data interception caused either by malicious attacks or accidental

  1. Adaptive Bio-Inspired Wireless Network Routing for Planetary Surface Exploration

    NASA Technical Reports Server (NTRS)

    Alena, Richard I.; Lee, Charles

    2004-01-01

    Wireless mobile networks suffer connectivity loss when used in a terrain that has hills, and valleys when line of sight is interrupted or range is exceeded. To resolve this problem and achieve acceptable network performance, we have designed an adaptive, configurable, hybrid system to automatically route network packets along the best path between multiple geographically dispersed modules. This is very useful in planetary surface exploration, especially for ad-hoc mobile networks, where computational devices take an active part in creating a network infrastructure, and can actually be used to route data dynamically and even store data for later transmission between networks. Using inspiration from biological systems, this research proposes to use ant trail algorithms with multi-layered information maps (topographic maps, RF coverage maps) to determine the best route through ad-hoc network at real time. The determination of best route is a complex one, and requires research into the appropriate metrics, best method to identify the best path, optimizing traffic capacity, network performance, reliability, processing capabilities and cost. Real ants are capable of finding the shortest path from their nest to a food source without visual sensing through the use of pheromones. They are also able to adapt to changes in the environment using subtle clues. To use ant trail algorithms, we need to define the probability function. The artificial ant is, in this case, a software agent that moves from node to node on a network graph. The function to calculate the fitness (evaluate the better path) includes: length of the network edge, the coverage index, topology graph index, and pheromone trail left behind by other ant agents. Each agent modifies the environment in two different ways: 1) Local trail updating: As the ant moves between nodes it updates the amount of pheromone on the edge; and 2) Global trail updating: When all ants have completed a tour the ant that found the

  2. Vehicle density based forwarding protocol for safety message broadcast in VANET.

    PubMed

    Huang, Jiawei; Huang, Yi; Wang, Jianxin

    2014-01-01

    In vehicular ad hoc networks (VANETs), the medium access control (MAC) protocol is of great importance to provide time-critical safety applications. Contemporary multihop broadcast protocols in VANETs usually choose the farthest node in broadcast range as the forwarder to reduce the number of forwarding hops. However, in this paper, we demonstrate that the farthest forwarder may experience large contention delay in case of high vehicle density. We propose an IEEE 802.11-based multihop broadcast protocol VDF to address the issue of emergency message dissemination. To achieve the tradeoff between contention delay and forwarding hops, VDF adaptably chooses the forwarder according to the vehicle density. Simulation results show that, due to its ability to decrease the transmission collisions, the proposed protocol can provide significantly lower broadcast delay.

  3. Vehicle Density Based Forwarding Protocol for Safety Message Broadcast in VANET

    PubMed Central

    Huang, Jiawei; Wang, Jianxin

    2014-01-01

    In vehicular ad hoc networks (VANETs), the medium access control (MAC) protocol is of great importance to provide time-critical safety applications. Contemporary multihop broadcast protocols in VANETs usually choose the farthest node in broadcast range as the forwarder to reduce the number of forwarding hops. However, in this paper, we demonstrate that the farthest forwarder may experience large contention delay in case of high vehicle density. We propose an IEEE 802.11-based multihop broadcast protocol VDF to address the issue of emergency message dissemination. To achieve the tradeoff between contention delay and forwarding hops, VDF adaptably chooses the forwarder according to the vehicle density. Simulation results show that, due to its ability to decrease the transmission collisions, the proposed protocol can provide significantly lower broadcast delay. PMID:25121125

  4. Concise review: no breakthroughs for human mesenchymal and embryonic stem cell culture: conditioned medium, feeder layer, or feeder-free; medium with fetal calf serum, human serum, or enriched plasma; serum-free, serum replacement nonconditioned medium, or ad hoc formula? All that glitters is not gold!

    PubMed

    Mannello, Ferdinando; Tonti, Gaetana A

    2007-07-01

    The choice of an optimal strategy of stem cell culture is at the moment an impossible task, and the elaboration of a culture medium adapted to the production of embryonic and adult mesenchymal stem cells for the clinical application of cell therapy remains a crucial matter. To make an informed choice, it is crucial to not underestimate the theoretical health risk of using xenogenic compounds, to limit the immunological reactions once stem cells are transplanted, to not overestimate the controversial results obtained with human serum, plasma, and blood derivatives, as well as to carefully examine the pros and cons of serum-free and ad hoc formulation strategies; besides that, to also maintain multipotentiality, self-renewal, and transplantability. The extent to which we are able to achieve effective cell therapies will depend on assimilating a rapidly developing base of scientific knowledge with the practical considerations of design, delivery, and host response. Although clinical studies have already started, many questions remain unsolved, and concomitantly even more evidence on suitable and safe off-the-shelf products (mainly xeno-free) for embryonic and mesenchymal stem cells is cropping up, even though there should be no rush to enter the clinical stage while the underlying basic research is still not so solid; this solely will lead to high-quality translational research, without making blunders stemming from the assumption that all that glitters is not gold. Disclosure of potential conflicts of interest is found at the end of this article.

  5. Demand on Temporary Parallel Route Recovery for Frequent Link Failure in VANET

    NASA Astrophysics Data System (ADS)

    Sakthi Ganesh, M.; Venkata krishna, P.

    2015-03-01

    Vehicular Ad-hoc Network (VANET) is an upcoming technology for communication between vehicles during the trip, which provides Internet connectivity resulting in safer roads giving access important alerts and comfort during the slip. VANET technology integrates wireless cellular and ad hoc for seamless connectivity between vehicles. VANETs are organizations that allow vehicles to communicate with each other. Wireless-vice can send data to nearby vehicles, and messages can be transported from one vehicle to another, so that the information can be broadcast throughout the metropolis. In the network, link failure is very common due to the high mobility of clients. Frequent link failure occurs as packets do not arrive at the respective goals. The mechanism proposed here establishes a form of route discovery packet parallel to the real time application to be extradited to the destination, while minimizing losses. The primary aim is to establish parallel paths during link failure scenarios for real-time applications to provide information to their destination safely. During link failures, the recovery road is parallel to the fixed temporary parallel path between the nodes. The node before the link failure packet buffers, after setting the new parallel paths before the packets stored in the buffer via the destination newly created path.

  6. Sensor Sharing in Mobile Ad-Hoc Networks

    ERIC Educational Resources Information Center

    Mitra, Pramita

    2013-01-01

    Today's modern mobile devices (such as smartphones and tablets) present great potential for growth of many novel, powerful, but also highly demanding applications. However, most mobile devices/users operate in isolation from one another, i.e., they are not aware of the presence of other devices in their proximity. There are numerous situations…

  7. Applying Ad Hoc Institutional Research Findings to College Strategic Planning

    ERIC Educational Resources Information Center

    Clagett, Craig A.

    2004-01-01

    Environmental scanning, enrollment forecasting, budget analyses, and institutional effectiveness assessment are examples of the explicit contributions institutional research offices make to campus strategic planning.

  8. Report of ad hoc OTEC cold water pipe committee

    SciTech Connect

    Barr, R.; Giannotti, J.; Deuchler, W.; Scotti, R.; Stadter, J.; Walsh, J. P.; Weiss, R.

    1980-02-01

    Now that the design work on the pilot plant is scheduled to start in the near future, DOE has considered it essential that an overall look be taken at the cold water pipe design process. The VSE Corporation, in its role as a support contractor to DOE, was tasked to organize a small study group to answer the question, Where do we stand on the verification of the computer models of the cold water pipe response by experimental measurements. The committee has studied all the available results of the cold water pipe development program. This report summarizes those results. The development and present capabilities of the computer programs used to calculate the response of a cold water pipe attached to a platform under known at-sea conditions are discussed. The various cold water pipe designs that have been done using the computer programs are summarized. The experiments that have been conducted up to the present time to measure the response of cold water pipes at-sea and in experimental tanks are described. The results of these experiments are presented. The experimental results are compared with the predictions made with the analytical computer programs. Conclusions drawn as a result of this analysis are presented and some recommendations are made. (WHK)

  9. Attaining Realistic Simulations of Mobile Ad-hoc Networks

    DTIC Science & Technology

    2010-06-01

    Optimized 2-8 Network Engineering Tools ( OPNET ) [33], and Global Mobile Information Systems Simulation Library (GloMoSim) [30]. NS and GloMoSim are...both provided as open use software to researchers, whereas OPNET is a commercial simulation engine. While all of these engines can simulate MANETs, the...key environmental and technical aspects have yet to be accurately modeled in any of the major simulation engines such as OPNET Modeler, NS-2, or

  10. Report of the AD HOC Committee on Patent Documentation.

    ERIC Educational Resources Information Center

    Urbach, Peter; And Others

    The Committee was established in September 1967 to study and make recommendations on Recommendation XXIX and XXX of the Report of the President's Commission on the Patent System. Based on interviews with Patent Office officials, patent examiners and classifiers and a review of Patent Office studies and documents, the Committee concluded that the…

  11. Report of the Ad Hoc Group for Irradiated Food Program

    DTIC Science & Technology

    1975-05-01

    food irradiation technology. The last briefer of this session was from the Energy Research and Development Administration, who monitors the...34remnants" of the Atomic Energy Commissions low-dosti irradiation program (Memoranduum For Record at Appendix F). In addition to inputs from these meetings...Agriculture, and State; the Energy Research and Development Administration; the National Science Foundation; the International Congress of Radiation

  12. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2007-08-01

    In both cases the impact of jamming and hostile intercept is being considered. The possibility of hostile action to deny services or exploit the...network accessing to a common access point. We see that the ace-only scheme is ur future plan includes orks under partial loading (as opposed to...time scheme and the sp remarkable. Future plan : O • Effect of channel estimation errors on throughput of large networks • Fundamental understanding

  13. IPv6 Autoconfiguration for Mobile Ad-Hoc Networks: AUTOLSR

    DTIC Science & Technology

    2010-09-01

    these are the MANET border routers ( MBR ). Each network partition is characterized by a network parameter set (NPS) which includes sufficient...of time ; and depending on operative conditions, later may be joined. MBR ware gateways for communication between tactical MANETs and command centers...list have already been applied, a random suffix is generated. 1.4 MANET border router The MBR (MANET Border Router) has two roles: it serves as a

  14. Army Science Board Ad Hoc Subgroup Report, Manning Army Systems

    DTIC Science & Technology

    1982-09-01

    Jr. (USMC-Ret) Dr. K. C. Emerson Dr. P. Phillip Sidwell Dr. John R. Tooley SECURITY CLASSIFICATION OF THIS PAGEOWi"! Data Et .1 I DEPARTMENT OF...Drive Sanibel, FL 33957 (813) 472-9156 Dr. P. Phillip Sidwell Post Office Box 88531 Atlanta, GA 30338 (404) 394-2548 Dr. John R. Tooley ...30338 . Dr. John R. Tooley * Dean, School of Engineering and Applied Science University of Evansvllle Post Office Box 329 Evansvllle, IN 47702 DIST-4 1 •I

  15. Modeling Terrain Impact on Mobile Ad Hoc Networks (MANET) Connectivity

    DTIC Science & Technology

    2014-05-01

    O R D E F E N S E A N A L Y S E S INSTITUTE FOR DEFENSE ANALYSES 4850 Mark Center Drive Alexandria, Virginia 22311-1882 IDA Document NS D-5246 Log: H...AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Institute for Defense Analyses ...Institute for Defense Analyses 4850 Mark Center Drive, Alexandria, Virginia 22311-1882 • (703) 845-2000. This material may be reproduced by or for the

  16. Report of the ADE Ad Hoc Committee on Governance.

    ERIC Educational Resources Information Center

    ADE Bulletin, 2001

    2001-01-01

    Considers how decisions about curriculum, hiring, and institutional policies have changed due to increasing regulatory, legal, and financial pressures conflicting with ever-magnifying and multiplying sense of need. Identifies three dominant models of institutional governance--models that represent different emphases and that, for the purposes of…

  17. Secure Ad Hoc Networking on an Android Platform

    DTIC Science & Technology

    2014-05-01

    Haselsteiner, E. & Breitfuß, K. (2006) Security in near field communication (nfc), in Workshop on RFID Security RFIDSec. Khan, S., Banuri, S. H. K...security on mobile phones, in Workshop on RFID Security–RFIDSec09. UNCLASSIFIED 21 DSTO–TN–1390 UNCLASSIFIED Appendix A Certificate Authority Key

  18. Ad hoc methods for accurate determination of Bader's atomic boundary

    NASA Astrophysics Data System (ADS)

    Polestshuk, Pavel M.

    2013-08-01

    In addition to the recently published triangulation method [P. M. Polestshuk, J. Comput. Chem. 34, 206 (2013)], 10.1002/jcc.23121, two new highly accurate approaches, ZFSX and SINTY, for the integration over an atomic region covered by a zero-flux surface (zfs) were developed and efficiently interfaced into the TWOE program. ZFSX method was realized as three independent modules (ZFSX-1, ZFSX-3, and ZFSX-5) handling interatomic surfaces of a different complexity. Details of algorithmic implementation of ZFSX and SINTY are discussed. A special attention to an extended analysis of errors in calculations of atomic properties is paid. It was shown that uncertainties in zfs determination caused by ZFSX and SINTY approaches contribute negligibly (less than 10-6 a.u.) to the total atomic integration errors. Moreover, the new methods are able to evaluate atomic integrals with a reasonable time and can be universally applied for the systems of any complexity. It is suggested, therefore, that ZFSX and SINTY can be regarded as benchmark methods for the computation of any Quantum Theory of Atoms in Molecules atomic property.

  19. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2009-08-01

    transmissions. a) Average SEP/ BEP analysis with Channel Estimation Errors and Feedback Delay In this work, we analyze average symbol error probability...packet has to be re-transmitted. 64 Extensive analytical results quantifying the impact of fading on average symbol and error probability (SEP/ BEP ...are available for various modulation schemes. However, in slow fading situations, there is no mapping between the average SEP/ BEP and the average PEP

  20. A Discovery Process for Initializing Ad Hoc Underwater Acoustic Networks

    DTIC Science & Technology

    2008-12-01

    Bay (near the Seaweb network gateway node). ..................................................................... 15 Figure 11. Bellhop eigenray ...compute the eigenray traces and channel impulse response using code from Torres [18] that employs a Bellhop Gaussian beam tracing acoustic propagation...model. Figure 11 depicts the eigenray traces and channel impulse response for the Halifax trial environment with a transmit frequency of 12 kHz, water

  1. Mobile Ad Hoc Networks: An Evaluation of Smartphone Technologies

    DTIC Science & Technology

    2011-10-01

    dans un tel environnement et offre une comparaison des diverses plateformes de téléphone intel- ligent disponibles à l’égard de leurs capacités et...CORA CR 2011-169 5 Networking and the Open System Interconnection Model The International Organization for Standardization (ISO) began working on a

  2. Flow Control in Wireless Ad-Hoc Networks

    DTIC Science & Technology

    2009-01-01

    these mechanisms can be improved in order to fine-tune TCP under various networking environments. Low, Paganini and Doyle [36] study TCP from a control...Derivative Securities, M. A. H. Dempster and S. R. Pliska, Eds., vol. 16. Cambridge University Press , 1997, pp. 504–527. [30] KUSHNER, H. J., AND DIMASI...wireless networks: Optimality and stability. IEEE Trans- actions on Information Theory 55, 9 (Sept. 2009), 4087–4098. 76 [36] LOW, S. H., PAGANINI , F

  3. Mobile Ad-Hoc Networking on Android Devices

    DTIC Science & Technology

    2014-03-01

    2012 Android and iOS devices dominated the market share with 75.0% and 14.9%, respectively (5). This strongly suggested Android devices as our platform...networks, it lacks the ability to create them. This lack of ability and the fact that the Android operating system is open source, while iOS is very...Battlefield Scenarios; U.S. Army Research Laboratory: Aberdeen Proving Ground, MD To be published in 2014. 4. Kerr, D. Android beats iOS 5-to-1 in Q3

  4. Device Discovery in Frequency Hopping Wireless Ad Hoc Networks

    DTIC Science & Technology

    2004-09-01

    Thesis, Blekinge Institute of Technology, Available: http://www.inst-informatica.pt/v20/cid/ biblioteca digital /telecomunicacoes...Single-Channel Ground And Airborne Radio System,” Available: http://www.fas.org/man/dod-101/sys/land/docs/sincgars.pdf, 1996. Skl01. B. Sklar, Digital

  5. Credible Mobile and Ad Hoc Network Simulation-Based Studies

    DTIC Science & Technology

    2006-10-26

    packet radio. In Proceed- ings of the 9th ARRL /CRRL Amateur Radio Computer Networking Conference, pages 134-140, 1990. [45] H. Kee. NAM support for...Selected Areas in Communications (JSAC), pages 1335-1346, 2004. [102] P. Welch. The Computer Performance Modeling Handbook , chapter The Statis- tical

  6. Ad Hoc Network Architecture for Multi-Media Networks

    DTIC Science & Technology

    2007-12-01

    Ethernet traffic while 1.9On  characterizes video traffic. These four parameters are in the range of self-similarity (i.e. , H is the Hurst ...For self-similar traffic,  falls in the range of 1 2  [24], which is related to . H is the Hurst parameter given in Equation 0.5 1H  (3.4...2y x , which is the exponent of  1 r , can be separated into 1 2y x     . Thus, Equation (4.2) is the new equation used to compute and . In

  7. A Survey on Trust Management for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-07-01

    negative consequences if the expectation is not conrmed than positive consequences if it is conrmed. In addition, Hardin [27] and Rotter [28...insights provided by our internal ARL staff including Eliza- beth Bowman, Kevin Chan, Natalie Ivanic, and Brian Rivera. The authors also give special...Processes, Carl Hovland Memorial Lectures Series, New Haven and London: Yale University Press, 1973. [27] R. Hardin , “The Street-Level Epistemology of

  8. Robust Connectivity in Sensory and Ad Hoc Network

    DTIC Science & Technology

    2011-02-01

    known that, for a scalar Gaussian MAC, orthogonal transmissions, e.g., frequency division multiple access ( FDMA ) or time division multiple access...TDMA) under an average power constraint, can achieve the sum capacity [11]. As such, although FDMA and TDMA is suboptimal in terms of the entire...proportional singular values, well aligned singular vectors and appropriate power constraints in order for FDMA /TDMA to achieve the sum capacity

  9. Ad hoc methods for accurate determination of Bader's atomic boundary.

    PubMed

    Polestshuk, Pavel M

    2013-08-07

    In addition to the recently published triangulation method [P. M. Polestshuk, J. Comput. Chem. 34, 206 (2013)], two new highly accurate approaches, ZFSX and SINTY, for the integration over an atomic region covered by a zero-flux surface (zfs) were developed and efficiently interfaced into the TWOE program. ZFSX method was realized as three independent modules (ZFSX-1, ZFSX-3, and ZFSX-5) handling interatomic surfaces of a different complexity. Details of algorithmic implementation of ZFSX and SINTY are discussed. A special attention to an extended analysis of errors in calculations of atomic properties is paid. It was shown that uncertainties in zfs determination caused by ZFSX and SINTY approaches contribute negligibly (less than 10(-6) a.u.) to the total atomic integration errors. Moreover, the new methods are able to evaluate atomic integrals with a reasonable time and can be universally applied for the systems of any complexity. It is suggested, therefore, that ZFSX and SINTY can be regarded as benchmark methods for the computation of any Quantum Theory of Atoms in Molecules atomic property.

  10. Self-organized Anonymous Authentication in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Freudiger, Julien; Raya, Maxim; Hubaux, Jean-Pierre

    Pervasive communications bring along new privacy challenges, fueled by the capability of mobile devices to communicate with, and thus “sniff on”, each other directly. We design a new mechanism that aims at achieving location privacy in these forthcoming mobile networks, whereby mobile nodes collect the pseudonyms of the nodes they encounter to generate their own privacy cloaks. Thus, privacy emerges from the mobile network and users gain control over the disclosure of their locations. We call this new paradigm self-organized location privacy. In this work, we focus on the problem of self-organized anonymous authentication that is a necessary prerequisite for location privacy. We investigate, using graph theory, the optimality of different cloak constructions and evaluate with simulations the achievable anonymity in various network topologies. We show that peer-to-peer wireless communications and mobility help in the establishment of self-organized anonymous authentication in mobile networks.

  11. Experiments with OLSR Routing in a MANET

    DTIC Science & Technology

    2006-12-01

    philippe.jacquet @inria.fr / plesse lecomte @celar.fr Abstract Wireless ad-hoc networks (MANETs) are autonomous , self-configuring and adaptive networks...of wireless technologies. Wireless ad-hoc networks are autonomous , self-configuring and self-adaptive net- works. Their ability to be operational...doctrine integrates all the tactical components : warriors, Unmanned Ground Vehicules (UGV), Unmanned Aerial Vehicules (UAV), tactical vehicules

  12. Scalability enhancement of AODV using local link repairing

    NASA Astrophysics Data System (ADS)

    Jain, Jyoti; Gupta, Roopam; Bandhopadhyay, T. K.

    2014-09-01

    Dynamic change in the topology of an ad hoc network makes it difficult to design an efficient routing protocol. Scalability of an ad hoc network is also one of the important criteria of research in this field. Most of the research works in ad hoc network focus on routing and medium access protocols and produce simulation results for limited-size networks. Ad hoc on-demand distance vector (AODV) is one of the best reactive routing protocols. In this article, modified routing protocols based on local link repairing of AODV are proposed. Method of finding alternate routes for next-to-next node is proposed in case of link failure. These protocols are beacon-less, means periodic hello message is removed from the basic AODV to improve scalability. Few control packet formats have been changed to accommodate suggested modification. Proposed protocols are simulated to investigate scalability performance and compared with basic AODV protocol. This also proves that local link repairing of proposed protocol improves scalability of the network. From simulation results, it is clear that scalability performance of routing protocol is improved because of link repairing method. We have tested protocols for different terrain area with approximate constant node densities and different traffic load.

  13. Contact Graph Routing

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.

    2011-01-01

    Contact Graph Routing (CGR) is a dynamic routing system that computes routes through a time-varying topology of scheduled communication contacts in a network based on the DTN (Delay-Tolerant Networking) architecture. It is designed to enable dynamic selection of data transmission routes in a space network based on DTN. This dynamic responsiveness in route computation should be significantly more effective and less expensive than static routing, increasing total data return while at the same time reducing mission operations cost and risk. The basic strategy of CGR is to take advantage of the fact that, since flight mission communication operations are planned in detail, the communication routes between any pair of bundle agents in a population of nodes that have all been informed of one another's plans can be inferred from those plans rather than discovered via dialogue (which is impractical over long one-way-light-time space links). Messages that convey this planning information are used to construct contact graphs (time-varying models of network connectivity) from which CGR automatically computes efficient routes for bundles. Automatic route selection increases the flexibility and resilience of the space network, simplifying cross-support and reducing mission management costs. Note that there are no routing tables in Contact Graph Routing. The best route for a bundle destined for a given node may routinely be different from the best route for a different bundle destined for the same node, depending on bundle priority, bundle expiration time, and changes in the current lengths of transmission queues for neighboring nodes; routes must be computed individually for each bundle, from the Bundle Protocol agent's current network connectivity model for the bundle s destination node (the contact graph). Clearly this places a premium on optimizing the implementation of the route computation algorithm. The scalability of CGR to very large networks remains a research topic

  14. Assessing Routing Strategies for Cognitive Radio Sensor Networks

    PubMed Central

    Zubair, Suleiman; Fisal, Norsheila; Baguda, Yakubu S.; Saleem, Kashif

    2013-01-01

    Interest in the cognitive radio sensor network (CRSN) paradigm has gradually grown among researchers. This concept seeks to fuse the benefits of dynamic spectrum access into the sensor network, making it a potential player in the next generation (NextGen) network, which is characterized by ubiquity. Notwithstanding its massive potential, little research activity has been dedicated to the network layer. By contrast, we find recent research trends focusing on the physical layer, the link layer and the transport layers. The fact that the cross-layer approach is imperative, due to the resource-constrained nature of CRSNs, can make the design of unique solutions non-trivial in this respect. This paper seeks to explore possible design opportunities with wireless sensor networks (WSNs), cognitive radio ad-hoc networks (CRAHNs) and cross-layer considerations for implementing viable CRSN routing solutions. Additionally, a detailed performance evaluation of WSN routing strategies in a cognitive radio environment is performed to expose research gaps. With this work, we intend to lay a foundation for developing CRSN routing solutions and to establish a basis for future work in this area. PMID:24077319

  15. Content-based image retrieval using greedy routing

    NASA Astrophysics Data System (ADS)

    Don, Anthony; Hanusse, Nicolas

    2008-01-01

    In this paper, we propose a new concept for browsing and searching in large collections of content-based indexed images. Our approach is inspired by greedy routing algorithms used in distributed networks. We define a navigation graph, called navgraph, whose vertices represent images. The edges of the navgraph are computed according to a similarity measure between indexed images. The resulting graph can be seen as an ad-hoc network of images in which a greedy routing algorithm can be applied for retrieval purposes. A request for a target image consists of a walk in the navigation graph using a greedy approach : starting from an arbitrary vertex/image, the neighbors of the current vertex are presented to the user, who iteratively selects the vertex which is the most similar to the target. We present the navgraph construction and prove its efficiency for greedy routing. We also propose a specific content-descriptor that we compare to the MPEG7 Color Layout Descriptor. Experimental results with test-users show the usability of this approach.

  16. Satellite Communications Using Commercial Protocols

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Griner, James H.; Dimond, Robert; Frantz, Brian D.; Kachmar, Brian; Shell, Dan

    2000-01-01

    NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space- based communications networks as well as expectations for future protocol development. It serves as a reference point from which the detailed work can be readily accessed. Areas that will be addressed include asynchronous-transfer-mode quality of service; completed and ongoing work of the Internet Engineering Task Force; data-link-layer protocol development for unidirectional link routing; and protocols for aeronautical applications, including mobile Internet protocol routing for wireless/mobile hosts and the aeronautical telecommunications network protocol.

  17. A fast and scalable content transfer protocol (FSCTP) for VANET based architecture

    NASA Astrophysics Data System (ADS)

    Santamaria, A. F.; Scala, F.; Sottile, C.; Tropea, M.; Raimondo, P.

    2016-05-01

    In the modern Vehicular Ad-hoc Networks (VANET) based systems even more applications require lot of data to be exchanged among vehicles and infrastructure entities. Due to mobility issues and unplanned events that may occurs it is important that contents should be transferred as fast as possible by taking into account consistence of the exchanged data and reliability of the connections. In order to face with these issues, in this work we propose a new transfer data protocol called Fast and Scalable Content Transfer Protocol (FSCTP). This protocol allows a data transfer by using a bidirectional channel among content suppliers and receivers exploiting several cooperative sessions. Each session will be based on User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) to start and manage data transfer. Often in urban area the VANET scenario is composed of several vehicle and infrastructures points. The main idea is to exploit ad-hoc connections between vehicles to reach content suppliers. Moreover, in order to obtain a faster data transfer, more than one session is exploited to achieve a higher transfer rate. Of course it is important to manage data transfer between suppliers to avoid redundancy and resource wastages. The main goal is to instantiate a cooperative multi-session layer efficiently managed in a VANET environment exploiting the wide coverage area and avoiding common issues known in this kind of scenario. High mobility and unstable connections between nodes are some of the most common issues to address, thus a cooperative work between network, transport and application layers needs to be designed.

  18. A Routing Protocol for Packet Radio Networks

    DTIC Science & Technology

    1995-01-01

    table of node K is a matrix containing, for each destination L and each neighbor of K (say M ), the distance to L ( NEOPRQ ) and the predecessor ( S OP Q...identifier T The distance to the destination ( N OP ) T The predecessor of the shortest path chosen toward L ( S OP ) T The successor ( U OP ) of the shortest...P and the predecessor is updated as S OP À ¾ S Q P . Thus, a node can determine whether or not an update received from M affects its other distance

  19. "Recalculating Route".

    PubMed

    Baum, Neil

    2015-01-01

    Can you imagine going to a doctor who uses a paper chart, sends you a bill on a ledger card, and handwrites a prescription? You wouldn't have a great deal of confidence that the clinical skills of the doctor were up to date. This would be an example of a doctor who did not "recalculate his or her route." This article provides 10 examples of adjustments that have been made in medicine where the route has been recalculated.

  20. Mobility based multicast routing in wireless mesh networks

    NASA Astrophysics Data System (ADS)

    Jain, Sanjeev; Tripathi, Vijay S.; Tiwari, Sudarshan

    2013-01-01

    There exist two fundamental approaches to multicast routing namely minimum cost trees and shortest path trees. The (MCT's) minimum cost tree is one which connects receiver and sources by providing a minimum number of transmissions (MNTs) the MNTs approach is generally used for energy constraint sensor and mobile ad hoc networks. In this paper we have considered node mobility and try to find out simulation based comparison of the (SPT's) shortest path tree, (MST's) minimum steiner trees and minimum number of transmission trees in wireless mesh networks by using the performance metrics like as an end to end delay, average jitter, throughput and packet delivery ratio, average unicast packet delivery ratio, etc. We have also evaluated multicast performance in the small and large wireless mesh networks. In case of multicast performance in the small networks we have found that when the traffic load is moderate or high the SPTs outperform the MSTs and MNTs in all cases. The SPTs have lowest end to end delay and average jitter in almost all cases. In case of multicast performance in the large network we have seen that the MSTs provide minimum total edge cost and minimum number of transmissions. We have also found that the one drawback of SPTs, when the group size is large and rate of multicast sending is high SPTs causes more packet losses to other flows as MCTs.

  1. Quality of Service Routing in Manet Using a Hybrid Intelligent Algorithm Inspired by Cuckoo Search.

    PubMed

    Rajalakshmi, S; Maguteeswaran, R

    2015-01-01

    A hybrid computational intelligent algorithm is proposed by integrating the salient features of two different heuristic techniques to solve a multiconstrained Quality of Service Routing (QoSR) problem in Mobile Ad Hoc Networks (MANETs) is presented. The QoSR is always a tricky problem to determine an optimum route that satisfies variety of necessary constraints in a MANET. The problem is also declared as NP-hard due to the nature of constant topology variation of the MANETs. Thus a solution technique that embarks upon the challenges of the QoSR problem is needed to be underpinned. This paper proposes a hybrid algorithm by modifying the Cuckoo Search Algorithm (CSA) with the new position updating mechanism. This updating mechanism is derived from the differential evolution (DE) algorithm, where the candidates learn from diversified search regions. Thus the CSA will act as the main search procedure guided by the updating mechanism derived from DE, called tuned CSA (TCSA). Numerical simulations on MANETs are performed to demonstrate the effectiveness of the proposed TCSA method by determining an optimum route that satisfies various Quality of Service (QoS) constraints. The results are compared with some of the existing techniques in the literature; therefore the superiority of the proposed method is established.

  2. Simple wavelength assignment protocol

    NASA Astrophysics Data System (ADS)

    Suryaputra, Stephen; Touch, Joseph D.; Bannister, Joseph A.

    2000-10-01

    IP routers can be coupled with wavelength-selective optical cross- connects to support existing Internet infrastructure in a wavelength division multiplexing (WDM) optical network. Because optical wavelength routing is transparent to IP, packets can bypass traditional forwarding and pass directly through the optical cross-connect, resulting in very high throughput and low delay routing. This approach shares features with label switching, but wavelengths are much more scarce resource than labels. Because optical switches have larger switching times than electronic switches, and wavelength conversions are expensive, wavelength label swapping is not easily done. Wavelength label assignments must consider these limitations to be practical in an optical environment. The performance of an instance of this approach, called Packet over Wavelengths (POW) has been simulated and studied. A new signaling protocol, Simple Wavelength Assignment Protocol (SWAP) is devised to be POW signaling protocol. SWAP takes into account the optical device limitations, and is designed to minimize wavelength conversion, utilize wavelengths with the merging of flows, and reduce the reconfiguration of optical switches. SWAP, to our knowledge, is the first approach to combine signaling and wavelength assignment in an on- line protocol. This paper describes high level SWAP design challenges, decision, and overhead.

  3. An Optimal Symmetric Secret Distribution of Star Networks

    DTIC Science & Technology

    2007-01-01

    itself be assisted by other sensors in terms of routing. However, the intermediate sensors can neither learn the contents of the message nor can...instantiation in ad-hoc networks. Computer Comunications , (29):200–215, 2006. [5] Aiyer A.S., Alvisi L, and Gouda M. G. Key grids: A protocol family for

  4. AFRL/Cornell Information Assurance Institute

    DTIC Science & Technology

    2007-11-02

    Election Protocol for Large Groups. DISC 2000 ( Toledo , Spain, October 2000). (61) Z. Haas, J. Y. Halpern and L. Li. Gossip-based ad hoc routing. Pro...Joseph Y. Halpern, Robert Harper, Neil Immerman, Phokion G. Ko- laitis, Moshe Y. Vardi, and Victor Vianu. The Unusual Effectiveness of Logic in Computer

  5. A Context-Aware Paradigm for Information Discovery and Dissemination in Mobile Environments

    ERIC Educational Resources Information Center

    Lundquist, Doug

    2011-01-01

    The increasing power and ubiquity of mobile wireless devices is enabling real-time information delivery for many diverse applications. A crucial question is how to allocate finite network resources efficiently and fairly despite the uncertainty common in highly dynamic mobile ad hoc networks. We propose a set of routing protocols, Self-Balancing…

  6. NIST cooperative laboratory for OSI routing technology

    SciTech Connect

    Montgomery, D.

    1994-05-23

    This document is one of two reports on the Integrated ISIS protocol. Required by the IAB/IESG in order for an Internet routing protocol to advance to Draft Standard Status. Integrated ISIS is an Interior Gateway Protocol and is designed to carry both IP and ISO CLNP routing information. Integrated ISIS is currently designated as a Proposed Standard. The protocol was first published in RFC 1195. Internet Draft was published subsequently to RFC 1195 and documents the current version of the protocol. This report documents experience with Integrated ISIS. This includes reports on interoperability testing, field experience and the current state of Integrated ISIS implementations. It also presents a summary of the Integrated ISIS Management Information Base (MIB), and a summary of the Integrated ISIS authentication mechanism.

  7. Exploration of an Opportunistic Overlaid Paradigm for Complex Networks via Stochastic Geometry

    DTIC Science & Technology

    2012-03-01

    gossip -based information exchange protocol , the M-GIKF, is presented. Un- der the assumption of global detectability of the signal/observation model...Cui, “A Selection Region Based Routing Protocol for Ran- dom Mobile ad hoc Networks,” Proceedings: IEEE GLOBECOM Workshop on Heterogeneous, Multi...all static; ii) the primary nodes are static while the secondary nodes are mobile. With the proposed protocols for the two tiers, we show that the

  8. Communications protocol

    NASA Technical Reports Server (NTRS)

    Zhou, Xiaoming (Inventor); Baras, John S. (Inventor)

    2010-01-01

    The present invention relates to an improved communications protocol which increases the efficiency of transmission in return channels on a multi-channel slotted Alohas system by incorporating advanced error correction algorithms, selective retransmission protocols and the use of reserved channels to satisfy the retransmission requests.

  9. Design and performance evaluation of a distributed OFDMA-based MAC protocol for MANETs.

    PubMed

    Park, Jaesung; Chung, Jiyoung; Lee, Hyungyu; Lee, Jung-Ryun

    2014-01-01

    In this paper, we propose a distributed MAC protocol for OFDMA-based wireless mobile ad hoc multihop networks, in which the resource reservation and data transmission procedures are operated in a distributed manner. A frame format is designed considering the characteristics of OFDMA that each node can transmit or receive data to or from multiple nodes simultaneously. Under this frame structure, we propose a distributed resource management method including network state estimation and resource reservation processes. We categorize five types of logical errors according to their root causes and show that two of the logical errors are inevitable while three of them are avoided under the proposed distributed MAC protocol. In addition, we provide a systematic method to determine the advertisement period of each node by presenting a clear relation between the accuracy of estimated network states and the signaling overhead. We evaluate the performance of the proposed protocol in respect of the reservation success rate and the success rate of data transmission. Since our method focuses on avoiding logical errors, it could be easily placed on top of the other resource allocation methods focusing on the physical layer issues of the resource management problem and interworked with them.

  10. Design and Performance Evaluation of a Distributed OFDMA-Based MAC Protocol for MANETs

    PubMed Central

    Chung, Jiyoung; Lee, Hyungyu; Lee, Jung-Ryun

    2014-01-01

    In this paper, we propose a distributed MAC protocol for OFDMA-based wireless mobile ad hoc multihop networks, in which the resource reservation and data transmission procedures are operated in a distributed manner. A frame format is designed considering the characteristics of OFDMA that each node can transmit or receive data to or from multiple nodes simultaneously. Under this frame structure, we propose a distributed resource management method including network state estimation and resource reservation processes. We categorize five types of logical errors according to their root causes and show that two of the logical errors are inevitable while three of them are avoided under the proposed distributed MAC protocol. In addition, we provide a systematic method to determine the advertisement period of each node by presenting a clear relation between the accuracy of estimated network states and the signaling overhead. We evaluate the performance of the proposed protocol in respect of the reservation success rate and the success rate of data transmission. Since our method focuses on avoiding logical errors, it could be easily placed on top of the other resource allocation methods focusing on the physical layer issues of the resource management problem and interworked with them. PMID:25133254

  11. Routing architecture and security for airborne networks

    NASA Astrophysics Data System (ADS)

    Deng, Hongmei; Xie, Peng; Li, Jason; Xu, Roger; Levy, Renato

    2009-05-01

    Airborne networks are envisioned to provide interconnectivity for terrestial and space networks by interconnecting highly mobile airborne platforms. A number of military applications are expected to be used by the operator, and all these applications require proper routing security support to establish correct route between communicating platforms in a timely manner. As airborne networks somewhat different from traditional wired and wireless networks (e.g., Internet, LAN, WLAN, MANET, etc), security aspects valid in these networks are not fully applicable to airborne networks. Designing an efficient security scheme to protect airborne networks is confronted with new requirements. In this paper, we first identify a candidate routing architecture, which works as an underlying structure for our proposed security scheme. And then we investigate the vulnerabilities and attack models against routing protocols in airborne networks. Based on these studies, we propose an integrated security solution to address routing security issues in airborne networks.

  12. Optical Circuit Switched Protocol

    NASA Technical Reports Server (NTRS)

    Monacos, Steve P. (Inventor)

    2000-01-01

    The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

  13. Positioning clinical nurse specialists and nurse practitioners as change champions to implement a pain protocol in long-term care.

    PubMed

    Kaasalainen, Sharon; Ploeg, Jenny; Donald, Faith; Coker, Esther; Brazil, Kevin; Martin-Misener, Ruth; Dicenso, Alba; Hadjistavropoulos, Thomas

    2015-04-01

    Pain management for older adults in long-term care (LTC) has been recognized as a problem internationally. The purpose of this study was to explore the role of a clinical nurse specialist (CNS) and nurse practitioner (NP) as change champions during the implementation of an evidence-based pain protocol in LTC. In this exploratory, multiple-case design study, we collected data from two LTC homes in Ontario, Canada. Three data sources were used: participant observation of an NP and a CNS for 18 hours each over a 3-week period; CNS and NP diaries recording strategies, barriers, and facilitators to the implementation process; and interviews with members of the interdisciplinary team to explore perceptions about the NP and CNS role in implementing the pain protocol. Data were analyzed using thematic content analysis. The NP and CNS used a variety of effective strategies to promote pain management changes in practice including educational outreach with team members, reminders to nursing staff to highlight the pain protocol and educate about practice changes, chart audits and feedback to the nursing staff, interdisciplinary working group meetings, ad hoc meetings with nursing staff, and resident assessment using advanced skills. The CNS and NP are ideal champions to implement pain management protocols and likely other quality improvement initiatives.

  14. Genetic algorithms for route discovery.

    PubMed

    Gelenbe, Erol; Liu, Peixiang; Lainé, Jeremy

    2006-12-01

    Packet routing in networks requires knowledge about available paths, which can be either acquired dynamically while the traffic is being forwarded, or statically (in advance) based on prior information of a network's topology. This paper describes an experimental investigation of path discovery using genetic algorithms (GAs). We start with the quality-of-service (QoS)-driven routing protocol called "cognitive packet network" (CPN), which uses smart packets (SPs) to dynamically select routes in a distributed autonomic manner based on a user's QoS requirements. We extend it by introducing a GA at the source routers, which modifies and filters the paths discovered by the CPN. The GA can combine the paths that were previously discovered to create new untested but valid source-to-destination paths, which are then selected on the basis of their "fitness." We present an implementation of this approach, where the GA runs in background mode so as not to overload the ingress routers. Measurements conducted on a network test bed indicate that when the background-traffic load of the network is light to medium, the GA can result in improved QoS. When the background-traffic load is high, it appears that the use of the GA may be detrimental to the QoS experienced by users as compared to CPN routing because the GA uses less timely state information in its decision making.

  15. A Model of Onion Routing with Provable Anonymity

    NASA Astrophysics Data System (ADS)

    Feigenbaum, Joan; Johnson, Aaron; Syverson, Paul

    Onion routing is a scheme for anonymous communication that is designed for practical use. Until now, however, it has had no formal model and therefore no rigorous analysis of its anonymity guarantees. We give an IO-automata model of an onion-routing protocol and, under possibilistic definitions, characterize the situations in which anonymity and unlinkability are guaranteed.

  16. Reliable Multihop Broadcast Protocol with a Low-Overhead Link Quality Assessment for ITS Based on VANETs in Highway Scenarios

    PubMed Central

    Galaviz-Mosqueda, Alejandro; Villarreal-Reyes, Salvador; Galeana-Zapién, Hiram; Rubio-Loyola, Javier; Covarrubias-Rosales, David H.

    2014-01-01

    Vehicular ad hoc networks (VANETs) have been identified as a key technology to enable intelligent transport systems (ITS), which are aimed to radically improve the safety, comfort, and greenness of the vehicles in the road. However, in order to fully exploit VANETs potential, several issues must be addressed. Because of the high dynamic of VANETs and the impairments in the wireless channel, one key issue arising when working with VANETs is the multihop dissemination of broadcast packets for safety and infotainment applications. In this paper a reliable low-overhead multihop broadcast (RLMB) protocol is proposed to address the well-known broadcast storm problem. The proposed RLMB takes advantage of the hello messages exchanged between the vehicles and it processes such information to intelligently select a relay set and reduce the redundant broadcast. Additionally, to reduce the hello messages rate dependency, RLMB uses a point-to-zone link evaluation approach. RLMB performance is compared with one of the leading multihop broadcast protocols existing to date. Performance metrics show that our RLMB solution outperforms the leading protocol in terms of important metrics such as packet dissemination ratio, overhead, and delay. PMID:25133224

  17. Reliable multihop broadcast protocol with a low-overhead link quality assessment for ITS based on VANETs in highway scenarios.

    PubMed

    Galaviz-Mosqueda, Alejandro; Villarreal-Reyes, Salvador; Galeana-Zapién, Hiram; Rubio-Loyola, Javier; Covarrubias-Rosales, David H

    2014-01-01

    Vehicular ad hoc networks (VANETs) have been identified as a key technology to enable intelligent transport systems (ITS), which are aimed to radically improve the safety, comfort, and greenness of the vehicles in the road. However, in order to fully exploit VANETs potential, several issues must be addressed. Because of the high dynamic of VANETs and the impairments in the wireless channel, one key issue arising when working with VANETs is the multihop dissemination of broadcast packets for safety and infotainment applications. In this paper a reliable low-overhead multihop broadcast (RLMB) protocol is proposed to address the well-known broadcast storm problem. The proposed RLMB takes advantage of the hello messages exchanged between the vehicles and it processes such information to intelligently select a relay set and reduce the redundant broadcast. Additionally, to reduce the hello messages rate dependency, RLMB uses a point-to-zone link evaluation approach. RLMB performance is compared with one of the leading multihop broadcast protocols existing to date. Performance metrics show that our RLMB solution outperforms the leading protocol in terms of important metrics such as packet dissemination ratio, overhead, and delay.

  18. ZERO: probabilistic routing for deploy and forget Wireless Sensor Networks.

    PubMed

    Vilajosana, Xavier; Llosa, Jordi; Pacho, Jose Carlos; Vilajosana, Ignasi; Juan, Angel A; Vicario, Jose Lopez; Morell, Antoni

    2010-01-01

    As Wireless Sensor Networks are being adopted by industry and agriculture for large-scale and unattended deployments, the need for reliable and energy-conservative protocols become critical. Physical and Link layer efforts for energy conservation are not mostly considered by routing protocols that put their efforts on maintaining reliability and throughput. Gradient-based routing protocols route data through most reliable links aiming to ensure 99% packet delivery. However, they suffer from the so-called "hot spot" problem. Most reliable routes waste their energy fast, thus partitioning the network and reducing the area monitored. To cope with this "hot spot" problem we propose ZERO a combined approach at Network and Link layers to increase network lifespan while conserving reliability levels by means of probabilistic load balancing techniques.

  19. Implementation of direct routing mobile IP for solving triangular routing

    NASA Astrophysics Data System (ADS)

    Jang, Jongwook; Jang, SeongHo; Park, Miri; Lee, Dae-bong

    2001-10-01

    Mobility support on the network layer is of special importance, as the network layer holds together the huge Internet with common protocol IP. Although based on possibility different wireless or wired technologies, all nodes of the network should be able to communicate. Therefore, mobile IP(an extension of the classical IP) has been designed which enablemobility in the Internet without changing existing wired systems. However, mobile IP leaves some points unsolved. Especially, if it comes to security, efficiency of the packet flow that is called triangular routing. Especially triangular routing can cause unnecessary overhead for the network. Furthermore latency can increase dramatically. This is particularly unfortunate if two communicating hosts are separated by transatlantic links. In order to this problem, many methods like IPv6 and ROMIP are proposed. But these methods have limitation. In other words, they have not compatibility because of needing modification of original IP scheme. Especially ROMIP is very complex and the overhead of control message and processing are serious. The problem of inconsistency of Binding caches may occur too. We therefore propose and analyze the performance of the DRMIP (Direct Routing Mobile IP) which do not modify IP source needed in the sender, is compatible with IP and Mobile IP.

  20. Go the Yeshiva Route?

    ERIC Educational Resources Information Center

    Miles, Leland

    1981-01-01

    The Supreme Court's decision in the National Labor Relations Board v. Yeshiva University court case is discussed. National reactions to the case, arguments in favor of the Yeshiva route, arguments against the Yeshiva route, and financial considerations are discussed. (MLW)

  1. Learning multiple routes in homing pigeons.

    PubMed

    Flack, Andrea; Guilford, Tim; Biro, Dora

    2014-01-01

    The aerial lifestyle of central-place foraging birds allows wide-ranging movements, raising fundamental questions about their remarkable navigation and memory systems. For example, we know that pigeons (Columba livia), long-standing models for avian navigation, rely on individually distinct routes when homing from familiar sites. But it remains unknown how they cope with the task of learning several routes in parallel. Here, we examined how learning multiple routes influences homing in pigeons. We subjected groups of pigeons to different training protocols, defined by the sequence in which they were repeatedly released from three different sites, either sequentially, in rotation or randomly. We observed that pigeons from all groups successfully developed and applied memories of the different release sites (RSs), irrespective of the training protocol, and that learning several routes in parallel did not impair their capacity to quickly improve their homing efficiency over multiple releases. Our data also indicated that they coped with increasing RS uncertainty by adjusting both their initial behaviour upon release and subsequent homing efficiency. The results of our study broaden our understanding of avian route following and open new possibilities for studying learning and memory in free-flying animals.

  2. Using Sphinx to Improve Onion Routing Circuit Construction

    NASA Astrophysics Data System (ADS)

    Kate, Aniket; Goldberg, Ian

    This paper presents compact message formats for onion routing circuit construction using the Sphinx methodology developed for mixes. We significantly compress the circuit construction messages for three onion routing protocols that have emerged as enhancements to the Tor anonymizing network; namely, Tor with predistributed Diffie-Hellman values, pairing-based onion routing, and certificateless onion routing. Our new circuit constructions are also secure in the universal composability framework, a property that was missing from the original constructions. Further, we compare the performance of our schemes with their older counterparts as well as with each other.

  3. Suppressing traffic-driven epidemic spreading by adaptive routing strategy

    NASA Astrophysics Data System (ADS)

    Yang, Han-Xin; Wang, Zhen

    2016-12-01

    Despite extensive work on the interplay between traffic dynamics and epidemic spreading, the control of epidemic spreading by routing strategies has not received adequate attention. In this paper, we study the impact of efficient routing protocol on epidemic spreading. In the case of infinite node-delivery capacity, where the traffic is free of congestion, we find that that there exists optimal values of routing parameter, leading to the maximal epidemic threshold. This means that epidemic spreading can be effectively controlled by fine tuning the routing scheme. Moreover, we find that an increase in the average network connectivity and the emergence of traffic congestion can suppress the epidemic outbreak.

  4. Ad-Hoc Sensor Networks for Maritime Interdiction Operations and Regional Security

    DTIC Science & Technology

    2012-09-01

    which results in the coverage of every location of interest while other sensors of the network that do not possess vital data can hibernate to conserve...perform “sleep and wake up” and “ hibernation ” modes when there is no operational requirement. ARTEMIS has two platforms where sensors can be

  5. Towards Trust-based Cognitive Networks: A Survey of Trust Management for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2009-06-01

    destination.  Wormhole attack: A group of cooperating malicious nodes can pretend to connect two distant points in the network with a low-latency...communication link called wormhole link, causing disruptions in normal traffic load and flow.  Black hole attack: A malicious node, the so called

  6. Providing Effective Security in Mobile Ad Hoc Networks Without Affecting Bandwidth or Interoperability

    DTIC Science & Technology

    2008-12-01

    attacker access to a side-channel. 1.1 Wormhole Attacks Among the most difficult attacks to defend against in a MANET is the wormhole attack (Hu...Rev. 8-98) Prescribed by ANSI Std Z39-18 shown in Fig. 1, a wormhole attack consists of two colluding attackers acting in tandem to distort the...neighbours, and much of the traffic in their local areas, is now sent through a wormhole created by the attackers. Once implemented, the attackers

  7. Mission-Dependent Trust Management in Heterogeneous Military Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-06-01

    mission requirements. Bertocco and Ferrari [2] proposed a reputation system for a centralized system where an agent can join a group with particular...IPCCC’05), Phoenix, AX, 7-9 Apr. 2005, pp. 303-307. [2] C. Bertocco and C. Ferrari , “Context-Dependent Reputation Management for Soft Security in...Cologne, Germanu, 30 June – 3 July 2008, pp. 1-8. [19] A. Preece, M. Gomez , G. de Mel, W. Vasconcelos, D. Sleeman, S. Colley, G. Pearson, T. Pham

  8. Solving data-at-rest for the storage and retrieval of files in ad hoc networks

    NASA Astrophysics Data System (ADS)

    Knobler, Ron; Scheffel, Peter; Williams, Jonathan; Gaj, Kris; Kaps, Jens-Peter

    2013-05-01

    Based on current trends for both military and commercial applications, the use of mobile devices (e.g. smartphones and tablets) is greatly increasing. Several military applications consist of secure peer to peer file sharing without a centralized authority. For these military applications, if one or more of these mobile devices are lost or compromised, sensitive files can be compromised by adversaries, since COTS devices and operating systems are used. Complete system files cannot be stored on a device, since after compromising a device, an adversary can attack the data at rest, and eventually obtain the original file. Also after a device is compromised, the existing peer to peer system devices must still be able to access all system files. McQ has teamed with the Cryptographic Engineering Research Group at George Mason University to develop a custom distributed file sharing system to provide a complete solution to the data at rest problem for resource constrained embedded systems and mobile devices. This innovative approach scales very well to a large number of network devices, without a single point of failure. We have implemented the approach on representative mobile devices as well as developed an extensive system simulator to benchmark expected system performance based on detailed modeling of the network/radio characteristics, CONOPS, and secure distributed file system functionality. The simulator is highly customizable for the purpose of determining expected system performance for other network topologies and CONOPS.

  9. MUSIC algorithm DoA estimation for cooperative node location in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Warty, Chirag; Yu, Richard Wai; ElMahgoub, Khaled; Spinsante, Susanna

    In recent years the technological development has encouraged several applications based on distributed communications network without any fixed infrastructure. The problem of providing a collaborative early warning system for multiple mobile nodes against a fast moving object. The solution is provided subject to system level constraints: motion of nodes, antenna sensitivity and Doppler effect at 2.4 GHz and 5.8 GHz. This approach consists of three stages. The first phase consists of detecting the incoming object using a highly directive two element antenna at 5.0 GHz band. The second phase consists of broadcasting the warning message using a low directivity broad antenna beam using 2× 2 antenna array which then in third phase will be detected by receiving nodes by using direction of arrival (DOA) estimation technique. The DOA estimation technique is used to estimate the range and bearing of the incoming nodes. The position of fast arriving object can be estimated using the MUSIC algorithm for warning beam DOA estimation. This paper is mainly intended to demonstrate the feasibility of early detection and warning system using a collaborative node to node communication links. The simulation is performed to show the behavior of detecting and broadcasting antennas as well as performance of the detection algorithm. The idea can be further expanded to implement commercial grade detection and warning system

  10. Benchmarking of Whole Exome Sequencing and Ad Hoc Designed Panels for Genetic Testing of Hereditary Cancer.

    PubMed

    Feliubadaló, Lídia; Tonda, Raúl; Gausachs, Mireia; Trotta, Jean-Rémi; Castellanos, Elisabeth; López-Doriga, Adriana; Teulé, Àlex; Tornero, Eva; Del Valle, Jesús; Gel, Bernat; Gut, Marta; Pineda, Marta; González, Sara; Menéndez, Mireia; Navarro, Matilde; Capellá, Gabriel; Gut, Ivo; Serra, Eduard; Brunet, Joan; Beltran, Sergi; Lázaro, Conxi

    2017-01-04

    Next generation sequencing panels have been developed for hereditary cancer, although there is some debate about their cost-effectiveness compared to exome sequencing. The performance of two panels is compared to exome sequencing. Twenty-four patients were selected: ten with identified mutations (control set) and fourteen suspicious of hereditary cancer but with no mutation (discovery set). TruSight Cancer (94 genes) and a custom panel (122 genes) were assessed alongside exome sequencing. Eighty-three genes were targeted by the two panels and exome sequencing. More than 99% of bases had a read depth of over 30x in the panels, whereas exome sequencing covered 94%. Variant calling with standard settings identified the 10 mutations in the control set, with the exception of MSH6 c.255dupC using TruSight Cancer. In the discovery set, 240 unique non-silent coding and canonic splice-site variants were identified in the panel genes, 7 of them putatively pathogenic (in ATM, BARD1, CHEK2, ERCC3, FANCL, FANCM, MSH2). The three approaches identified a similar number of variants in the shared genes. Exomes were more expensive than panels but provided additional data. In terms of cost and depth, panels are a suitable option for genetic diagnostics, although exomes also identify variants in non-targeted genes.

  11. Simultaneous Localization, Calibration, and Tracking in an ad Hoc Sensor Network

    DTIC Science & Technology

    2005-04-26

    4] J. J. Leonard and P. M. Newman, “Consistent, convergent, and constant-time SLAM,” in IJCAI, 2003. [5] Y. Liu , R. Emery, D . Chakrabarti, W. Burgard...2001. [6] S. Thrun, Y. Liu , D . Koller, A.Y. Ng, Z. Ghahramani, and H. Durrant-Whyte, “Simultaneous localiza- tion and mapping with sparse extended...b r i d g e , m a 0 213 9 u s a — w w w. c s a i l . m i t . e d u April 26, 2005MIT-CSAIL-TR-2005-029 AIM-2005-016 Report Documentation Page

  12. Simultaneous Localization and Tracking in Wireless Ad-hoc Sensor Networks

    DTIC Science & Technology

    2005-05-31

    Technical report, MIT Computer Science and AI Lab, http:// nms.lcs.mit.edu/projects/ cricket /#papers, 2003. [2] D . P. Bertsekas and J. T. Tsitsiklis. Parallel...spatial relationships in robotics. In Uncertainity in Artificial Intelligence, 1988. [34] S. Thrun, Y. Liu , D . Koller, A.Y. Ng, Z. Ghahramani, and H...Taylor Technical Report m a s s a c h u s e t t s i n s t i t u t e o f t e c h n o l o g y, c a m b r i d g e , m a 0 213 9 u s a — w w w. c s a

  13. Probabilistic monitoring in intrusion detection module for energy efficiency in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    De Rango, Floriano; Lupia, Andrea

    2016-05-01

    MANETs allow mobile nodes communicating to each other using the wireless medium. A key aspect of these kind of networks is the security, because their setup is done without an infrastructure, so external nodes could interfere in the communication. Mobile nodes could be compromised, misbehaving during the multi-hop transmission of data, or they could have a selfish behavior to save energy, which is another important constraint in MANETs. The detection of these behaviors need a framework that takes into account the latest interactions among nodes, so malicious or selfish nodes could be detected also if their behavior is changed over time. The monitoring activity increases the energy consumption, so our proposal takes into account this issue reducing the energy required by the monitoring system, keeping the effectiveness of the intrusion detection system. The results show an improvement in the saved energy, improving the detection performance too.

  14. On the Connectivity and Multihop Delay of Ad Hoc Cognitive Radio Networks

    DTIC Science & Technology

    2010-05-01

    depends on the density of SUs and the traffic load of PUs. 9 Connectivity: Static Case When PTxs/ PRxs are static over time: PSfrag replacements λ P T...Connectivity: Dynamic Case When temporal dynamics of PTxs/ PRxs are sufficiently rich: PSfrag replacements λ P T (D en si ty of P T xs ) λS (Density of SUs)λ

  15. Enhancing the Effectiveness of Ad Hoc Units: A Revised Training Model

    DTIC Science & Technology

    2009-06-01

    1965, when Bruce Tuckman developed a unitary sequence to describe group dynamics, that the field really developed. The sequence which Tuckman ...described is the same for every group, consisting of forming, storming, norming, and performing.40 Tuckman postulates that as the team develops maturity...producing a successor leader so that the previous leader can move on to develop a new team. Tuckman and Mary Ann Jensen further amended the

  16. In-drilling alignment scheme for borehole assembly trajectory tracking over a wireless ad hoc network

    NASA Astrophysics Data System (ADS)

    Odei-Lartey, E.; Hartmann, K.

    2016-05-01

    This paper describes the feasibility and implementation of an In-drilling alignment method for an inertia navigation system based measurement while drilling system as applied to the vertical drilling process, where there is seldom direct access to a reference measurement due the communication network architecture and telemetry framework constraints. It involves the sequential measurement update of multiple nodes by the propagation of the reference measurement sequentially over nodes, each of which has an integrated inertia measurement unit sensor and runs the extended Kalman filter based signal processing unit, until the final measurement update of the main sensor node embedded in the borehole assembly is done. This is done particularly to keep track of the yaw angle position during the drilling process.

  17. 75 FR 33838 - NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    .... Asteroid detection, warning, response, and concepts for deflection. International coordination on planetary..., Advisory Committee Management Officer, National Aeronautics and Space Administration. BILLING CODE P...

  18. A probabilistic dynamic energy model for ad-hoc wireless sensors network with varying topology

    NASA Astrophysics Data System (ADS)

    Al-Husseini, Amal

    In this dissertation we investigate the behavior of Wireless Sensor Networks (WSNs) from the degree distribution and evolution perspective. In specific, we focus on implementation of a scale-free degree distribution topology for energy efficient WSNs. WSNs is an emerging technology that finds its applications in different areas such as environment monitoring, agricultural crop monitoring, forest fire monitoring, and hazardous chemical monitoring in war zones. This technology allows us to collect data without human presence or intervention. Energy conservation/efficiency is one of the major issues in prolonging the active life WSNs. Recently, many energy aware and fault tolerant topology control algorithms have been presented, but there is dearth of research focused on energy conservation/efficiency of WSNs. Therefore, we study energy efficiency and fault-tolerance in WSNs from the degree distribution and evolution perspective. Self-organization observed in natural and biological systems has been directly linked to their degree distribution. It is widely known that scale-free distribution bestows robustness, fault-tolerance, and access efficiency to system. Fascinated by these properties, we propose two complex network theoretic self-organizing models for adaptive WSNs. In particular, we focus on adopting the Barabasi and Albert scale-free model to fit into the constraints and limitations of WSNs. We developed simulation models to conduct numerical experiments and network analysis. The main objective of studying these models is to find ways to reducing energy usage of each node and balancing the overall network energy disrupted by faulty communication among nodes. The first model constructs the wireless sensor network relative to the degree (connectivity) and remaining energy of every individual node. We observed that it results in a scale-free network structure which has good fault tolerance properties in face of random node failures. The second model considers additional constraints on the maximum degree of each node as well as the energy consumption relative to degree changes. This gives more realistic results from a dynamical network perspective. It results in balanced network-wide energy consumption. The results show that networks constructed using the proposed approach have good properties for different centrality measures. The outcomes of the presented research are beneficial to building WSN control models with greater self-organization properties which leads to optimal energy consumption.

  19. A Discussion of Metrics for Parallelized Army Mobile ad hoc Network Simulations

    DTIC Science & Technology

    2011-09-01

    years including Yet Another Network Simulator (YANS), ns-2 and ns-3, OPNET , and ROSS (4–8). All of these approaches employ a discrete event simulator (DES...adding NetDMF awareness to the COMPOSER toolkit. Commercial tools, such as OPNET , also maintain a suite of tools for analysis of network simulation...Network Simulator-3 (ns-3). [6] Chang, X. Network Simulations with OPNET . In Winter Simulation Conference, 1999. [7] Khosa, I.; Haider, U.; Mosood, H

  20. Wireless Ad-Hoc Networks with Receiver Multipacket Reception: Performance Analysis and Signal Processing

    DTIC Science & Technology

    2007-11-02

    estimation and symbol detection algorithms are developed for long code wide-band CDMA systems , including systems with multirate and multicode...CDMA systems . If the spreading codes have good cross- and auto-correlation properties, the matched filter front- end suppresses multiaccess...selective fading, however, code orthogonality can not be guaranteed, and the conventional RAKE receiver that uses a bank of matched filters may perform