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Sample records for ad-hoc wireless network

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  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. 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…

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. Dynamic Hierarchical Sleep Scheduling for Wireless Ad-Hoc Sensor Networks

    PubMed Central

    Wen, Chih-Yu; Chen, Ying-Chih

    2009-01-01

    This paper presents two scheduling management schemes for wireless sensor networks, which manage the sensors by utilizing the hierarchical network structure and allocate network resources efficiently. A local criterion is used to simultaneously establish the sensing coverage and connectivity such that dynamic cluster-based sleep scheduling can be achieved. The proposed schemes are simulated and analyzed to abstract the network behaviors in a number of settings. The experimental results show that the proposed algorithms provide efficient network power control and can achieve high scalability in wireless sensor networks. PMID:22412343

  13. 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.

  14. 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

  15. 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

  16. Probabilistic Neural Network-Based Sensor Configuration in a Wireless Ad Hoc Network

    DTIC Science & Technology

    2004-12-20

    This paper describes a novel application of a probabilistic neural network for overcoming the computational complexity involved in performing sensor...overcome the computational complexity, we propose the use of a probabilistic neural network (PNN). The task for the PNN is to produce a distance

  17. Information Potential Fields Navigation in Wireless Ad-Hoc Sensor Networks

    PubMed Central

    Wei, Wei; Qi, Yong

    2011-01-01

    As wireless sensor networks (WSNs) are increasingly being deployed in some important applications, it becomes imperative that we consider application requirements in in-network processes. We intend to use a WSN to aid information querying and navigation within a dynamic and real-time environment. We propose a novel method that relies on the heat diffusion equation to finish the navigation process conveniently and easily. From the perspective of theoretical analysis, our proposed work holds the lower constraint condition. We use multiple scales to reach the goal of accurate navigation. We present a multi-scale gradient descent method to satisfy users’ requirements in WSNs. Formula derivations and simulations show that the method is accurately and efficiently able to solve typical sensor network configuration information navigation problems. Simultaneously, the structure of heat diffusion equation allows more flexibility and adaptability in searching algorithm designs. PMID:22163876

  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

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Adaptive Flow Control for Enabling Quality of Service in Tactical Ad Hoc Wireless Networks

    DTIC Science & Technology

    2010-12-01

    been employed as part of a QoS management system for wired networks in the Ama- ranth system [Hoover 2001]. In Amaranth , applications register their...reducing network congestion. This idea is similar to that seen in IntServ [Braden 1994] and in the Amaranth system [Hoover 2001], without the need...San Francisco, CA (USA), April 2001. IEEE, 2001. [Hoover 2001] Hoover, C., Hansen, J., Koopman, P. & Tamboli, S. “The Amaranth Framework: Policy

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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…

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Unsupervised learning in persistent sensing for target recognition by wireless ad hoc networks of ground-based sensors

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2008-04-01

    In previous work by the author, effective persistent and pervasive sensing for recognition and tracking of battlefield targets were seen to be achieved, using intelligent algorithms implemented by distributed mobile agents over a composite system of unmanned aerial vehicles (UAVs) for persistence and a wireless network of unattended ground sensors for pervasive coverage of the mission environment. While simulated performance results for the supervised algorithms of the composite system are shown to provide satisfactory target recognition over relatively brief periods of system operation, this performance can degrade by as much as 50% as target dynamics in the environment evolve beyond the period of system operation in which the training data are representative. To overcome this limitation, this paper applies the distributed approach using mobile agents to the network of ground-based wireless sensors alone, without the UAV subsystem, to provide persistent as well as pervasive sensing for target recognition and tracking. The supervised algorithms used in the earlier work are supplanted by unsupervised routines, including competitive-learning neural networks (CLNNs) and new versions of support vector machines (SVMs) for characterization of an unknown target environment. To capture the same physical phenomena from battlefield targets as the composite system, the suite of ground-based sensors can be expanded to include imaging and video capabilities. The spatial density of deployed sensor nodes is increased to allow more precise ground-based location and tracking of detected targets by active nodes. The "swarm" mobile agents enabling WSN intelligence are organized in a three processing stages: detection, recognition and sustained tracking of ground targets. Features formed from the compressed sensor data are down-selected according to an information-theoretic algorithm that reduces redundancy within the feature set, reducing the dimension of samples used in the target

  3. 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

  4. Modeling and Analysis of Energy Conservation Scheme Based on Duty Cycling in Wireless Ad Hoc Sensor Network

    PubMed Central

    Chung, Yun Won; Hwang, Ho Young

    2010-01-01

    In sensor network, energy conservation is one of the most critical issues since sensor nodes should perform a sensing task for a long time (e.g., lasting a few years) but the battery of them cannot be replaced in most practical situations. For this purpose, numerous energy conservation schemes have been proposed and duty cycling scheme is considered the most suitable power conservation technique, where sensor nodes alternate between states having different levels of power consumption. In order to analyze the energy consumption of energy conservation scheme based on duty cycling, it is essential to obtain the probability of each state. In this paper, we analytically derive steady state probability of sensor node states, i.e., sleep, listen, and active states, based on traffic characteristics and timer values, i.e., sleep timer, listen timer, and active timer. The effect of traffic characteristics and timer values on the steady state probability and energy consumption is analyzed in detail. Our work can provide sensor network operators guideline for selecting appropriate timer values for efficient energy conservation. The analytical methodology developed in this paper can be extended to other energy conservation schemes based on duty cycling with different sensor node states, without much difficulty. PMID:22219676

  5. Modeling and analysis of energy conservation scheme based on duty cycling in wireless ad hoc sensor network.

    PubMed

    Chung, Yun Won; Hwang, Ho Young

    2010-01-01

    In sensor network, energy conservation is one of the most critical issues since sensor nodes should perform a sensing task for a long time (e.g., lasting a few years) but the battery of them cannot be replaced in most practical situations. For this purpose, numerous energy conservation schemes have been proposed and duty cycling scheme is considered the most suitable power conservation technique, where sensor nodes alternate between states having different levels of power consumption. In order to analyze the energy consumption of energy conservation scheme based on duty cycling, it is essential to obtain the probability of each state. In this paper, we analytically derive steady state probability of sensor node states, i.e., sleep, listen, and active states, based on traffic characteristics and timer values, i.e., sleep timer, listen timer, and active timer. The effect of traffic characteristics and timer values on the steady state probability and energy consumption is analyzed in detail. Our work can provide sensor network operators guideline for selecting appropriate timer values for efficient energy conservation. The analytical methodology developed in this paper can be extended to other energy conservation schemes based on duty cycling with different sensor node states, without much difficulty.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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…

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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).

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  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. 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

  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. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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.

  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. 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

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. Advanced Wireless Integrated Navy Network

    DTIC Science & Technology

    2005-03-01

    Basing visualization of wireless technologies, Ad Hoc networks , network protocols, real-time resource allocation, Ultra Wideband (UWB) communications...4.1 TIP #1: Distributed MIMO UWB sensor networks incorporating software radio 67 4.2 TIP #2: Close-in UWB wireless with applications to Sea- Basing 68...4.3 TIP #3: Secure Ad Hoc Networks 73 4.4 TIP #4: Integration of Close-in UWB wireless with ESM crane for Sea Basing applications 75 5. FINANCIAL REPORT

  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. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Inter-Vehicular Ad Hoc Networks: From the Ground Truth to Algorithm Design and Testbed Architecture

    ERIC Educational Resources Information Center

    Giordano, Eugenio

    2011-01-01

    Many of the devices we interact with on a daily basis are currently equipped with wireless connectivity. Soon this will be extended to the vehicles we drive/ride every day. Wirelessly connected vehicles will form a new kind of network that will enable a wide set of innovative applications ranging from enhanced safety to entertainment. To…

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. Capacity Limit, Link Scheduling and Power Control in Wireless Networks

    ERIC Educational Resources Information Center

    Zhou, Shan

    2013-01-01

    The rapid advancement of wireless technology has instigated the broad deployment of wireless networks. Different types of networks have been developed, including wireless sensor networks, mobile ad hoc networks, wireless local area networks, and cellular networks. These networks have different structures and applications, and require different…

  11. 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

  12. 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

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

    DTIC Science & Technology

    2005-08-01

    electrical engineering of antenna array design and electronics; computer science of networking; and the mathematics of information and control theory...MIMO networks at this time. The COST 259 model does provide improvements over the GSM model since it adds direction of arrival statistics to the...an open research issue especially because the channel statistics are not yet known for mobile MIMO networks. Physical and network diversity could be

  14. 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.

  15. Delay Analysis of Max-Weight Queue Algorithm for Time-Varying Wireless Ad hoc Networks—Control Theoretical Approach

    NASA Astrophysics Data System (ADS)

    Chen, Junting; Lau, Vincent K. N.

    2013-01-01

    Max weighted queue (MWQ) control policy is a widely used cross-layer control policy that achieves queue stability and a reasonable delay performance. In most of the existing literature, it is assumed that optimal MWQ policy can be obtained instantaneously at every time slot. However, this assumption may be unrealistic in time varying wireless systems, especially when there is no closed-form MWQ solution and iterative algorithms have to be applied to obtain the optimal solution. This paper investigates the convergence behavior and the queue delay performance of the conventional MWQ iterations in which the channel state information (CSI) and queue state information (QSI) are changing in a similar timescale as the algorithm iterations. Our results are established by studying the stochastic stability of an equivalent virtual stochastic dynamic system (VSDS), and an extended Foster-Lyapunov criteria is applied for the stability analysis. We derive a closed form delay bound of the wireless network in terms of the CSI fading rate and the sensitivity of MWQ policy over CSI and QSI. Based on the equivalent VSDS, we propose a novel MWQ iterative algorithm with compensation to improve the tracking performance. We demonstrate that under some mild conditions, the proposed modified MWQ algorithm converges to the optimal MWQ control despite the time-varying CSI and QSI.

  16. 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

  17. A Decision Framework for Enhancing Mobile Ad Hoc Network Stability and Security

    DTIC Science & Technology

    2008-06-01

    views expressed in this thesis are those of the author and do not reflect the official policy or position of the Department of Defense or the U.S... THESIS STATEMENT...................................................................................5 D. CONTRIBUTIONS OF THIS RESEARCH...C. THESIS STATEMENT A MANET management process based on an ontological organization of network decision factors and device security characteristics

  18. A Performance Analysis of an Ad-hoc Ocean Sensor Network

    DTIC Science & Technology

    2006-12-01

    and reconnections . Also, the broadcasting of radio channels can be highly unstable and the network layer has to interact with the MAC layer for...will return the PATH variable that contains a list of previously included pathnames that is colon -delimited. 5. Finally, to verify that ns2 has been

  19. 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.

  20. 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

  1. 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.

  2. On the Connectivity and Multihop Delay of Ad Hoc Cognitive Radio Networks

    DTIC Science & Technology

    2011-04-01

    that we can move fast enough such that the driving time on the road is negligible. When the secondary network is instantaneously connected, there...and receiving activities of the primary users. Without loss of generality, we set TS = 1. At the beginning of each slot, the primary transmitters are...the transmission/interference range is a function of the pass- loss exponent. Thus, the pass- loss exponent affects the topology of the secondary

  3. Temporal Traffic Dynamics Improve the Connectivity of Ad Hoc Cognitive Radio Networks

    DTIC Science & Technology

    2014-02-12

    of nearby primary users. Using theories and techniques from continuum percolation and ergodicity, we analytically characterize the con- nectivity of...users depends on the transmitting and receiving activities of nearby primary users. Using theories and techniques from continuum percolation and...connectivity of homogeneous net- works (i.e., secondary network only) have been well studied in [6]–[14] and references therein. The theory of continuum 3Since

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. Energy Efficient and Stable Weight Based Clustering for Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Bouk, Safdar H.; Sasase, Iwao

    Recently several weighted clustering algorithms have been proposed, however, to the best of our knowledge; there is none that propagates weights to other nodes without weight message for leader election, normalizes node parameters and considers neighboring node parameters to calculate node weights. In this paper, we propose an Energy Efficient and Stable Weight Based Clustering (EE-SWBC) algorithm that elects cluster heads without sending any additional weight message. It propagates node parameters to its neighbors through neighbor discovery message (HELLO Message) and stores these parameters in neighborhood list. Each node normalizes parameters and efficiently calculates its own weight and the weights of neighboring nodes from that neighborhood table using Grey Decision Method (GDM). GDM finds the ideal solution (best node parameters in neighborhood list) and calculates node weights in comparison to the ideal solution. The node(s) with maximum weight (parameters closer to the ideal solution) are elected as cluster heads. In result, EE-SWBC fairly selects potential nodes with parameters closer to ideal solution with less overhead. Different performance metrics of EE-SWBC and Distributed Weighted Clustering Algorithm (DWCA) are compared through simulations. The simulation results show that EE-SWBC maintains fewer average numbers of stable clusters with minimum overhead, less energy consumption and fewer changes in cluster structure within network compared to DWCA.

  9. Decentralized Opportunistic Spectrum Resources Access Model and Algorithm toward Cooperative Ad-Hoc Networks

    PubMed Central

    Liu, Ming; Xu, Yang; Mohammed, Abdul-Wahid

    2016-01-01

    Limited communication resources have gradually become a critical factor toward efficiency of decentralized large scale multi-agent coordination when both system scales up and tasks become more complex. In current researches, due to the agent’s limited communication and observational capability, an agent in a decentralized setting can only choose a part of channels to access, but cannot perceive or share global information. Each agent’s cooperative decision is based on the partial observation of the system state, and as such, uncertainty in the communication network is unavoidable. In this situation, it is a major challenge working out cooperative decision-making under uncertainty with only a partial observation of the environment. In this paper, we propose a decentralized approach that allows agents cooperatively search and independently choose channels. The key to our design is to build an up-to-date observation for each agent’s view so that a local decision model is achievable in a large scale team coordination. We simplify the Dec-POMDP model problem, and each agent can jointly work out its communication policy in order to improve its local decision utilities for the choice of communication resources. Finally, we discuss an implicate resource competition game, and show that, there exists an approximate resources access tradeoff balance between agents. Based on this discovery, the tradeoff between real-time decision-making and the efficiency of cooperation using these channels can be well improved. PMID:26727504

  10. A maintenance scheme of communication link in mobile robot ad hoc networks based on potential field

    NASA Astrophysics Data System (ADS)

    Jiang, Hong; Jin, WenPing; Yang, GyoYing; Li, LeiMin

    2007-12-01

    Maintaining communication link in mobile robot networks between task robots and a control center is very important in some urgent application occasions such as remote danger detections. To offer a reliable multi-hop communication link, a link maintaining scheme based on artificial potential field is presented. The scheme is achieved by a task robot and communication relay ones. The task robot performs predefined tasks, and relay ones are simple robots which form a communication relay chain. When robots move towards destination in formation, a kind of attractive force created by communication quality is added to traditional potential field, and relay robots follow the task robot and automatically stop at adequate locations to form a relay chain from the control station to the task robot. In order to increase relay usage efficiency, when some relays are replaced by other short cut relays, the redundant relays can be reused by initiating another moving toward specified location. Simulation results show that the scheme can provide a reliable multi-hop communication link, and that the communication connection can be obtained through minimal number of relays.

  11. 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.

  12. Developing a Cooperative Intrusion Detection System for Wireless Sensor Networks

    DTIC Science & Technology

    2010-11-01

    security measures out. AWISSENET (Ad-hoc personal area network & WIreless Sensor SEcure NETwork) is a project funded by the European Union...Information and Communication Technologies Program that is focused on security and resilience across ad-hoc personal area networks and wireless sensor networks...and provides a security toolbox for trusted route selection, secure service discovery and intrusion detection. This paper deals with intrusion

  13. 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

  14. Scaling Laws for Heterogeneous Wireless Networks

    DTIC Science & Technology

    2009-09-01

    implementation. 210 Bibliography [1] Shuchin Aeron and Venkatesh Saligrama. Wireless ad hoc networks: Strategies and scaling laws for the fixed SNR...Aleksandar Jovičić, and Pramod Viswanath . On outer bounds to the capacity region of wireless networks. IEEE Transactions on In- formation Theory, 52...Aleksandar Jovičić, Pramod Viswanath , and Sanjeev R. Kulkarni. Upper bounds to transport capacity of wireless networks. IEEE Transactions on

  15. Advanced Wireless Integrated Navy Network - AWINN

    DTIC Science & Technology

    2005-09-30

    progress report No. 3 on AWINN hardware and software configurations of smart, wideband, multi-function antennas , secure configurable platform, close-in...and Robust Networks Visualization of Wireless Technology and Ad Hoc Networks Technology Integration Projects The Advanced Antennas Group has completed a...comprehensive investigation of Wideband and Ultra Wideband (UWB) antennas for the AWINN projects. The investigation concluded that Tapered Slot

  16. 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.

  17. Cross-Layer Resource Allocation for Wireless Visual Sensor Networks and Mobile Ad Hoc Networks

    DTIC Science & Technology

    2014-10-01

    source coding and channel coding, while it also has an amount of power necessary for sensing , processing, and transmission of the captured data. Hence...the source coding rate, channel coding rate, and power constitute the transmission parameters of each node. Naturally, each node compresses the...limitations in the bandwidth of the communication channel . Different video sequences have different bit rate requirements for their compression . Generally

  18. Implementation of Software Programmable Radios to Form Ad-Hoc Meshed Networks to Enhance Maritime Interception Operations

    DTIC Science & Technology

    2010-09-01

    Networks, Software Programmable Radios, MIMO , Ultra-wideband, MIO, VBSS 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18...locations where it was never possible before: in crowded urban environments, massive buildings, subway tunnels, - virtually anywhere.  Networks can be...Multiple Input / Multiple Output ( MIMO )  Network-Controlled Robotics (Unmanned Vehicles) 2. Possible Combination of TW220 and Small Satellites Software

  19. A Prototype System for Using Multiple Radios in Directional MANET (Mobile Ad Hoc Network): A NISE Funded Applied Research Project

    DTIC Science & Technology

    2013-09-01

    Reception Algorithms in WLANs with Directional Antennas for QoS Support,” IEEE Networks (May/June), vol. 19, no. 3, pp. 27–32. [11] C. Cirullo, R. Olsen...ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: a. REPORT b. ABSTRACT c. THIS PAGE 17. LIMITATION OF ABSTRACT 18. NUMBER OF

  20. 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

  1. 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

  2. Characterizing Data Streams Over IEEE 802.11b AD-HOC Wireless Networks

    DTIC Science & Technology

    2003-03-01

    system should correctly identify both as HTTP traffic. Also, if one text based e - mail is sent and one image... based e - mail is sent, the system should correctly classify both as e - mail . If the size of the time interval increases, more traffic is captured and...The IIS SMTP service only allows for the configuration of SMTP , not POP3 . Outlook Express requires the SMTP service to send an e - mail message

  3. Distributed Topology Organization and Transmission Scheduling in Wireless Ad Hoc Networks

    DTIC Science & Technology

    2004-01-01

    directional antennae on the intended communication links. We will call systems that tolerate secondary interference multi-channel systems, while systems where...channel defined by a different frequency hopping sequence). A group of devices sharing a common channel is called a piconet. Each piconet has a master...frequency hop the receiver to which is listening. Upon reception of the IAC packet, the receiver sleeps for a random time interval ( called RB delay

  4. Vehicle monitoring under Vehicular Ad-Hoc Networks (VANET) parameters employing illumination invariant correlation filters for the Pakistan motorway police

    NASA Astrophysics Data System (ADS)

    Gardezi, A.; Umer, T.; Butt, F.; Young, R. C. D.; Chatwin, C. R.

    2016-04-01

    A spatial domain optimal trade-off Maximum Average Correlation Height (SPOT-MACH) filter has been previously developed and shown to have advantages over frequency domain implementations in that it can be made locally adaptive to spatial variations in the input image background clutter and normalised for local intensity changes. The main concern for using the SPOT-MACH is its computationally intensive nature. However in the past enhancements techniques were proposed for the SPOT-MACH to make its execution time comparable to its frequency domain counterpart. In this paper a novel approach is discussed which uses VANET parameters coupled with the SPOT-MACH in order to minimise the extensive processing of the large video dataset acquired from the Pakistan motorways surveillance system. The use of VANET parameters gives us an estimation criterion of the flow of traffic on the Pakistan motorway network and acts as a precursor to the training algorithm. The use of VANET in this scenario would contribute heavily towards the computational complexity minimization of the proposed monitoring system.

  5. 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.

  6. 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.

  7. An Analysis of the Feasibility and Applicability of IEEE 802.x Wireless Mesh Networks within the Global Information Grid

    DTIC Science & Technology

    2004-09-01

    SIMPLE AD HOC AND MANET The authors have chosen to differentiate between wireless mesh networking and simple, wireless ad hoc networking in order to...TND) protocol is that it uses " differential " HELLO messages which only report changes in the status of 5 Ibid. 10...change report (additions and deletions) are sent in more frequent differential updates (e.g., every one second). Whenever possible, topology

  8. Quantifying and Assuring Information Transfer in Dynamic Heterogeneous Wireless Networks

    DTIC Science & Technology

    2012-07-31

    TERMS 15. NUMBER OF PAGES:12 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF...THIS PAGE Unclassified 19. SECURITY CLASSIFICATION OF ABSTRACT Unclassified 20. LIMITATION OF ABSTRACT NSN 7540-01-280-5500...for assurance of information transfer. Proposed and studied the use of Network Coding for secure communication in wireless ad hoc and sensor

  9. 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.

  10. Secure and Robust Clustering in Wireless Sensor Networks

    DTIC Science & Technology

    2008-07-20

    guarantee in hostile environments. For example, an adversary can create wormholes [14] or invisible nodes [20] to fool the sensor nodes that are far from each...selection and a centralized detection. The proposed neighbor validation is of independent interest; it can further improve the security of current wormhole ...Johnson. Packet leashes: A defense against wormhole attacks in wireless ad hoc networks. In Proceedings of INFOCOM, April 2003. [15] P. Krishna, N. H

  11. Wireless integrated sensing, processing, and display networks for site security

    NASA Astrophysics Data System (ADS)

    Morrison, Rick L.; Brady, David J.; Rittgers, Andrew; Stack, Ronald A.

    2001-02-01

    We consider data management on ad hoc networks of sensing and processing nodes. We describe the construction of simple nodes from off the shelf components (PC 104 single board computers with flash memory, video capture cards and 802.1 lb wireless interfaces). We describe a Java interface to controlling these nodes and accessing images and image processing algorithms. We demonstrate target tracking across nodes and the potential for heterogeneous sensor types.

  12. 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.

  13. Evaluation and Analysis of Node Localization Power Cost in Ad-hoc Wireless Sensor Networks with Mobility

    DTIC Science & Technology

    2006-03-01

    localization structure, and discusses some of the obstacles associated with common ranging and position estimation approaches. 5 The self-organizing...environment measurement errors due to obstacles , reflections, and variations in altitude [SHS01]. For example, the usable transmission range of an RSSI...free position estimation techniques rely on the results of trigonometry and/or geometry to derive position estimations from node connectivity information

  14. 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

  15. 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...

  16. 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....

  17. 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...

  18. 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...

  19. Graphical user interface for wireless sensor networks simulator

    NASA Astrophysics Data System (ADS)

    Paczesny, Tomasz; Paczesny, Daniel; Weremczuk, Jerzy

    2008-01-01

    Wireless Sensor Networks (WSN) are currently very popular area of development. It can be suited in many applications form military through environment monitoring, healthcare, home automation and others. Those networks, when working in dynamic, ad-hoc model, need effective protocols which must differ from common computer networks algorithms. Research on those protocols would be difficult without simulation tool, because real applications often use many nodes and tests on such a big networks take much effort and costs. The paper presents Graphical User Interface (GUI) for simulator which is dedicated for WSN studies, especially in routing and data link protocols evaluation.

  20. 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.

  1. Cognitive Radio Wireless Sensor Networks: Applications, Challenges and Research Trends

    PubMed Central

    Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

    2013-01-01

    A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized. PMID:23974152

  2. Cognitive radio wireless sensor networks: applications, challenges and research trends.

    PubMed

    Joshi, Gyanendra Prasad; Nam, Seung Yeob; Kim, Sung Won

    2013-08-22

    A cognitive radio wireless sensor network is one of the candidate areas where cognitive techniques can be used for opportunistic spectrum access. Research in this area is still in its infancy, but it is progressing rapidly. The aim of this study is to classify the existing literature of this fast emerging application area of cognitive radio wireless sensor networks, highlight the key research that has already been undertaken, and indicate open problems. This paper describes the advantages of cognitive radio wireless sensor networks, the difference between ad hoc cognitive radio networks, wireless sensor networks, and cognitive radio wireless sensor networks, potential application areas of cognitive radio wireless sensor networks, challenges and research trend in cognitive radio wireless sensor networks. The sensing schemes suited for cognitive radio wireless sensor networks scenarios are discussed with an emphasis on cooperation and spectrum access methods that ensure the availability of the required QoS. Finally, this paper lists several open research challenges aimed at drawing the attention of the readers toward the important issues that need to be addressed before the vision of completely autonomous cognitive radio wireless sensor networks can be realized.

  3. 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

  4. 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

  5. 802.11s Wireless Mesh Network Visualization Application

    NASA Technical Reports Server (NTRS)

    Mauldin, James Alexander

    2014-01-01

    Results of past experimentation at NASA Johnson Space Center showed that the IEEE 802.11s standard has better performance than the widely implemented alternative protocol B.A.T.M.A.N (Better Approach to Mobile Ad hoc Networking). 802.11s is now formally incorporated into the Wi- Fi 802.11-2012 standard, which specifies a hybrid wireless mesh networking protocol (HWMP). In order to quickly analyze changes to the routing algorithm and to support optimizing the mesh network behavior for our intended application a visualization tool was developed by modifying and integrating open source tools.

  6. World Without Wires: Is Your District Ready to Go Wireless?

    ERIC Educational Resources Information Center

    Villano, Matt

    2005-01-01

    In this article, the author presents the latest wireless equipments available in market. For starters, wireless networks offer mobility and flexibility: users of laptops, PDAs, tablet PCs, and wireless Voice over IP telephones can move freely about campus while staying connected to the Internet. There are two kinds of wireless networks: ad-hoc, or…

  7. 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

  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. Community Wireless Networks

    ERIC Educational Resources Information Center

    Feld, Harold

    2005-01-01

    With increasing frequency, communities are seeing the arrival of a new class of noncommercial broadband providers: community wireless networks (CWNs). Utilizing the same wireless technologies that many colleges and universities have used to create wireless networks on campus, CWNs are creating broadband access for free or at costs well below…

  13. A Computational Wireless Network Backplane: Performance in a Distributed Speaker Identification Application Postprint

    DTIC Science & Technology

    2008-12-01

    traffic patterns are intense but constrained to a local area. Examples include peer-to-peer applications or sensor data processing in the region. In such...vol. 30, no. 4, pp. 68–74, 1997. [7] J. Dean and S. Ghemawat, “ Mapreduce : simplified data processing on large clusters ,” Commun. ACM, vol. 51, no. 1...DWARF, a general distributed application execution framework for wireless ad-hoc networks which dynamically allocates computation resources and manages

  14. TCPL: A Defense against wormhole attacks in wireless sensor networks

    SciTech Connect

    Kumar, K. E. Naresh; Waheed, Mohd. Abdul; Basappa, K. Kari

    2010-10-26

    Do In this paper presents recent advances in technology have made low-cost, low-power wireless sensors with efficient energy consumption. A network of such nodes can coordinate among themselves for distributed sensing and processing of certain data. For which, we propose an architecture to provide a stateless solution in sensor networks for efficient routing in wireless sensor networks. This type of architecture is known as Tree Cast. We propose a unique method of address allocation, building up multiple disjoint trees which are geographically inter-twined and rooted at the data sink. Using these trees, routing messages to and from the sink node without maintaining any routing state in the sensor nodes is possible. In this paper, we introduce the wormhole attack, a severe attack in ad hoc networks that is particularly challenging to defend against. The wormhole attack is possible even if the attacker has not compromised any hosts and even if all communication provides authenticity and confidentiality. In the wormhole attack, an attacker records packets (or bits) at one location in the network, tunnels them to another location, and retransmits them there into the network. The wormhole attack can form a serious threat in wireless networks, especially against many sensor network routing protocols and location-based wireless security systems. For example, most existing ad hoc network routing protocols, without some mechanism to defend against the wormhole attack, would be unable to find routes longer than one or two hops, severely disrupting communication. We present a new, general mechanism, called packet leashes, for detecting and thus defending against wormhole attacks, and we present a specific protocol, called TIK, that implements leashes.

  15. Wireless Mesh Networks

    NASA Astrophysics Data System (ADS)

    Ishmael, Johnathan; Race, Nicholas

    Wireless Mesh Networks have emerged as an important technology in building next-generation networks. They are seen to have a range of benefits over traditional wired and wireless networks including low deployment costs, high scalability and resiliency to faults. Moreover, Wireless Mesh Networks (WMNs) are often described as being autonomic with self-* (healing and configuration) properties and their popularity has grown both as a research platform and as a commercially exploitable technology.

  16. Information Transfer Ion Wireless Networks

    DTIC Science & Technology

    2010-07-01

    conferences with proceed- ings to be made available online in the IEEE Xplore database, namely IFIP Wireless Days (WD 2008) at Dubai, UAE, and the...Poland, May 2008, pp. 61-64, IEEE Xplore , DOI = 10.1109/INFTECH. 2008.4621591. 2. J. Konorski, IEEE 802.11 LAN Capacity: Incentives and Incentive...2008, Dubai, UAE, Nov. 2008, IEEE Xplore DOI = 10.1109/WD.2008.4812857. 4. J. Konorski, QoS Provision in an Ad Hoc IEEE 802.11 WLAN: A Bayesian War

  17. Information Transfer in Wireless Networks

    DTIC Science & Technology

    2010-07-01

    conferences with proceed- ings to be made available online in the IEEE Xplore database, namely IFIP Wireless Days (WD 2008) at Dubai, UAE, and the...Poland, May 2008, pp. 61-64, IEEE Xplore , DOI = 10.1109/INFTECH. 2008.4621591. 2. J. Konorski, IEEE 802.11 LAN Capacity: Incentives and Incentive...2008, Dubai, UAE, Nov. 2008, IEEE Xplore DOI = 10.1109/WD.2008.4812857. 4. J. Konorski, QoS Provision in an Ad Hoc IEEE 802.11 WLAN: A Bayesian War

  18. Latency-Efficient Communication in Wireless Mesh Networks under Consideration of Large Interference Range

    NASA Astrophysics Data System (ADS)

    Xin, Qin; Yao, Xiaolan; Engelstad, Paal E.

    2010-09-01

    Wireless Mesh Networking is an emerging communication paradigm to enable resilient, cost-efficient and reliable services for the future-generation wireless networks. We study here the minimum-latency communication primitive of gossiping (all-to-all communication) in multi-hop ad-hoc Wireless Mesh Networks (WMNs). Each mesh node in the WMN is initially given a message and the objective is to design a minimum-latency schedule such that each mesh node distributes its message to all other mesh nodes. Minimum-latency gossiping problem is well known to be NP-hard even for the scenario in which the topology of the WMN is known to all mesh nodes in advance. In this paper, we propose a new latency-efficient approximation scheme that can accomplish gossiping task in polynomial time units in any ad-hoc WMN under consideration of Large Interference Range (LIR), e.g., the interference range is much larger than the transmission range. To the best of our knowledge, it is first time to investigate such a scenario in ad-hoc WMNs under LIR, our algorithm allows the labels (e.g., identifiers) of the mesh nodes to be polynomially large in terms of the size of the WMN, which is the first time that the scenario of large labels has been considered in ad-hoc WMNs under LIR. Furthermore, our gossiping scheme can be considered as a framework which can be easily implied to the scenario under consideration of mobility-related issues since we assume that the mesh nodes have no knowledge on the network topology even for its neighboring mesh nodes.

  19. 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

  20. Multimedia wireless networking

    NASA Astrophysics Data System (ADS)

    Jain, Rajeev; Alwan, Abeer; Gerla, Mario; Kleinrock, Leonard; Villasenor, John D.; Belzer, Ben; Boring, Walter; Molloy, Stephen; Nazareth, Sean; Siqueira, Marcio; Short, Joel; Tsai, Jack

    1996-03-01

    Current wireless network systems (e.g. metropolitan cellular) are constrained by fixed bandwidth allocations and support only a narrow range of services (voice and low bit-rate data). To overcome these constraints and advance the state of the art in wireless multimedia communications, we are developing variable-rate video and speech compression algorithms, and wireless node architectures that will enable peer-to-peer multimedia networking even with very low bandwidth. To support this objective, each wireless node must support new applications (for multimedia), advances in networking and source coding to support multimedia under limited bandwidth conditions (wireless), advances in physical layer design to support robust, low power, high packet throughput links, low power DSP for multimedia compression, and an architectural strategy to integrate these components into an efficient node. The algorithms and architectures to support this functionality are presented here, together with some preliminary results on network performance.

  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. Resource optimization scheme for multimedia-enabled wireless mesh networks.

    PubMed

    Ali, Amjad; Ahmed, Muhammad Ejaz; Piran, Md Jalil; Suh, Doug Young

    2014-08-08

    Wireless mesh networking is a promising technology that can support numerous multimedia applications. Multimedia applications have stringent quality of service (QoS) requirements, i.e., bandwidth, delay, jitter, and packet loss ratio. Enabling such QoS-demanding applications over wireless mesh networks (WMNs) require QoS provisioning routing protocols that lead to the network resource underutilization problem. Moreover, random topology deployment leads to have some unused network resources. Therefore, resource optimization is one of the most critical design issues in multi-hop, multi-radio WMNs enabled with multimedia applications. Resource optimization has been studied extensively in the literature for wireless Ad Hoc and sensor networks, but existing studies have not considered resource underutilization issues caused by QoS provisioning routing and random topology deployment. Finding a QoS-provisioned path in wireless mesh networks is an NP complete problem. In this paper, we propose a novel Integer Linear Programming (ILP) optimization model to reconstruct the optimal connected mesh backbone topology with a minimum number of links and relay nodes which satisfies the given end-to-end QoS demands for multimedia traffic and identification of extra resources, while maintaining redundancy. We further propose a polynomial time heuristic algorithm called Link and Node Removal Considering Residual Capacity and Traffic Demands (LNR-RCTD). Simulation studies prove that our heuristic algorithm provides near-optimal results and saves about 20% of resources from being wasted by QoS provisioning routing and random topology deployment.

  3. Resource Optimization Scheme for Multimedia-Enabled Wireless Mesh Networks

    PubMed Central

    Ali, Amjad; Ahmed, Muhammad Ejaz; Piran, Md. Jalil; Suh, Doug Young

    2014-01-01

    Wireless mesh networking is a promising technology that can support numerous multimedia applications. Multimedia applications have stringent quality of service (QoS) requirements, i.e., bandwidth, delay, jitter, and packet loss ratio. Enabling such QoS-demanding applications over wireless mesh networks (WMNs) require QoS provisioning routing protocols that lead to the network resource underutilization problem. Moreover, random topology deployment leads to have some unused network resources. Therefore, resource optimization is one of the most critical design issues in multi-hop, multi-radio WMNs enabled with multimedia applications. Resource optimization has been studied extensively in the literature for wireless Ad Hoc and sensor networks, but existing studies have not considered resource underutilization issues caused by QoS provisioning routing and random topology deployment. Finding a QoS-provisioned path in wireless mesh networks is an NP complete problem. In this paper, we propose a novel Integer Linear Programming (ILP) optimization model to reconstruct the optimal connected mesh backbone topology with a minimum number of links and relay nodes which satisfies the given end-to-end QoS demands for multimedia traffic and identification of extra resources, while maintaining redundancy. We further propose a polynomial time heuristic algorithm called Link and Node Removal Considering Residual Capacity and Traffic Demands (LNR-RCTD). Simulation studies prove that our heuristic algorithm provides near-optimal results and saves about 20% of resources from being wasted by QoS provisioning routing and random topology deployment. PMID:25111241

  4. 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…

  5. 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...

  6. On Modeling Viral Diffusion in Heterogeneous Wireless Networks

    NASA Astrophysics Data System (ADS)

    Nguyen, Hoai-Nam; Shinoda, Yoichi

    Smart phones and computers now are able to co-work in a wireless environment where malware can propagate. Although many investigations have modeled the spread of malware, little has been done to take into account different characteristics of items to see how they affect disease diffusion in an ad hoc network. We have therefore developed a novel framework, consisting of two models, which consider diversity of objects as well as interactions between their different classes. Our framework is able to produce a huge result space thus makes it appropriate to describe many viral proliferating scenarios. Additionally, we have developed a formula to calculate the possible average number of newly infected devices in the considered system. An important contribution of our work is the comprehension of item diversity, which states that a mixture of device types causes a bigger malware spread as the number of device types in the network increases.

  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. 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

  9. Wireless nanosensor network system

    NASA Astrophysics Data System (ADS)

    Oh, Sechang; Kwon, Hyukjun; Kegley, Lauren; Yoon, Hargsoon; Varadan, Vijay K.

    2009-03-01

    Many types of wireless modules are being developed to enhance wireless performance with low power consumption, compact size, high data rates, and wide range coverage. However trade-offs must be taken into consideration in order to satisfy all aspects of wireless performance. For example, in order to increase the data rate and wide range coverage, power consumption should be sacrificed. To overcome these drawbacks, the paper presents a wireless client module which offers low power consumption along with a wireless receiver module that has the strength to provide high data rates and wide range coverage. Adopting Zigbee protocol in the wireless client module, the power consumption performance is enhanced so that it plays a part of the mobile device. On the other hand, the wireless receiver module, as adopting Zigbee and Wi-Fi protocol, provides high data rate, wide range coverage, and easy connection to the existing Internet network so that it plays a part of the portable device. This module demonstrates monitoring of gait analysis. The results show that the sensing data being measured can be monitored in any remote place with access to the Internet network.

  10. Wireless Sensors Network (Sensornet)

    NASA Technical Reports Server (NTRS)

    Perotti, J.

    2003-01-01

    The Wireless Sensor Network System presented in this paper provides a flexible reconfigurable architecture that could be used in a broad range of applications. It also provides a sensor network with increased reliability; decreased maintainability costs, and assured data availability by autonomously and automatically reconfiguring to overcome communication interferences.

  11. A Comparison of Alternative Distributed Dynamic Cluster Formation Techniques for Industrial Wireless Sensor Networks.

    PubMed

    Gholami, Mohammad; Brennan, Robert W

    2016-01-06

    In this paper, we investigate alternative distributed clustering techniques for wireless sensor node tracking in an industrial environment. The research builds on extant work on wireless sensor node clustering by reporting on: (1) the development of a novel distributed management approach for tracking mobile nodes in an industrial wireless sensor network; and (2) an objective comparison of alternative cluster management approaches for wireless sensor networks. To perform this comparison, we focus on two main clustering approaches proposed in the literature: pre-defined clusters and ad hoc clusters. These approaches are compared in the context of their reconfigurability: more specifically, we investigate the trade-off between the cost and the effectiveness of competing strategies aimed at adapting to changes in the sensing environment. To support this work, we introduce three new metrics: a cost/efficiency measure, a performance measure, and a resource consumption measure. The results of our experiments show that ad hoc clusters adapt more readily to changes in the sensing environment, but this higher level of adaptability is at the cost of overall efficiency.

  12. A Comparison of Alternative Distributed Dynamic Cluster Formation Techniques for Industrial Wireless Sensor Networks

    PubMed Central

    Gholami, Mohammad; Brennan, Robert W.

    2016-01-01

    In this paper, we investigate alternative distributed clustering techniques for wireless sensor node tracking in an industrial environment. The research builds on extant work on wireless sensor node clustering by reporting on: (1) the development of a novel distributed management approach for tracking mobile nodes in an industrial wireless sensor network; and (2) an objective comparison of alternative cluster management approaches for wireless sensor networks. To perform this comparison, we focus on two main clustering approaches proposed in the literature: pre-defined clusters and ad hoc clusters. These approaches are compared in the context of their reconfigurability: more specifically, we investigate the trade-off between the cost and the effectiveness of competing strategies aimed at adapting to changes in the sensing environment. To support this work, we introduce three new metrics: a cost/efficiency measure, a performance measure, and a resource consumption measure. The results of our experiments show that ad hoc clusters adapt more readily to changes in the sensing environment, but this higher level of adaptability is at the cost of overall efficiency. PMID:26751447

  13. Analysis of Wireless Sensor Network Topology and Estimation of Optimal Network Deployment by Deterministic Radio Channel Characterization

    PubMed Central

    Aguirre, Erik; Lopez-Iturri, Peio; Azpilicueta, Leire; Astrain, José Javier; Villadangos, Jesús; Falcone, Francisco

    2015-01-01

    One of the main challenges in the implementation and design of context-aware scenarios is the adequate deployment strategy for Wireless Sensor Networks (WSNs), mainly due to the strong dependence of the radiofrequency physical layer with the surrounding media, which can lead to non-optimal network designs. In this work, radioplanning analysis for WSN deployment is proposed by employing a deterministic 3D ray launching technique in order to provide insight into complex wireless channel behavior in context-aware indoor scenarios. The proposed radioplanning procedure is validated with a testbed implemented with a Mobile Ad Hoc Network WSN following a chain configuration, enabling the analysis and assessment of a rich variety of parameters, such as received signal level, signal quality and estimation of power consumption. The adoption of deterministic radio channel techniques allows the design and further deployment of WSNs in heterogeneous wireless scenarios with optimized behavior in terms of coverage, capacity, quality of service and energy consumption. PMID:25664434

  14. Analysis of wireless sensor network topology and estimation of optimal network deployment by deterministic radio channel characterization.

    PubMed

    Aguirre, Erik; Lopez-Iturri, Peio; Azpilicueta, Leire; Astrain, José Javier; Villadangos, Jesús; Falcone, Francisco

    2015-02-05

    One of the main challenges in the implementation and design of context-aware scenarios is the adequate deployment strategy for Wireless Sensor Networks (WSNs), mainly due to the strong dependence of the radiofrequency physical layer with the surrounding media, which can lead to non-optimal network designs. In this work, radioplanning analysis for WSN deployment is proposed by employing a deterministic 3D ray launching technique in order to provide insight into complex wireless channel behavior in context-aware indoor scenarios. The proposed radioplanning procedure is validated with a testbed implemented with a Mobile Ad Hoc Network WSN following a chain configuration, enabling the analysis and assessment of a rich variety of parameters, such as received signal level, signal quality and estimation of power consumption. The adoption of deterministic radio channel techniques allows the design and further deployment of WSNs in heterogeneous wireless scenarios with optimized behavior in terms of coverage, capacity, quality of service and energy consumption.

  15. Wireless Network Security Using Randomness

    DTIC Science & Technology

    2012-06-19

    REPORT WIRELESS NETWORK SECURITY USING RANDOMNESS 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: The present invention provides systems and methods for... securing communications in a wireless network by utilizing the inherent randomness of propagation errors to enable legitimate users to dynamically...Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS Patent, security , wireless networks, randomness Sheng Xiao, Weibo Gong

  16. 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.

  17. 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)...

  18. 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...

  19. 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...

  20. 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...

  1. 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

  2. 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.

  3. 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.

  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. 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.

  6. Insecurity of Wireless Networks

    SciTech Connect

    Sheldon, Frederick T; Weber, John Mark; Yoo, Seong-Moo; Pan, W. David

    2012-01-01

    Wireless is a powerful core technology enabling our global digital infrastructure. Wi-Fi networks are susceptible to attacks on Wired Equivalency Privacy, Wi-Fi Protected Access (WPA), and WPA2. These attack signatures can be profiled into a system that defends against such attacks on the basis of their inherent characteristics. Wi-Fi is the standard protocol for wireless networks used extensively in US critical infrastructures. Since the Wired Equivalency Privacy (WEP) security protocol was broken, the Wi-Fi Protected Access (WPA) protocol has been considered the secure alternative compatible with hardware developed for WEP. However, in November 2008, researchers developed an attack on WPA, allowing forgery of Address Resolution Protocol (ARP) packets. Subsequent enhancements have enabled ARP poisoning, cryptosystem denial of service, and man-in-the-middle attacks. Open source systems and methods (OSSM) have long been used to secure networks against such attacks. This article reviews OSSMs and the results of experimental attacks on WPA. These experiments re-created current attacks in a laboratory setting, recording both wired and wireless traffic. The article discusses methods of intrusion detection and prevention in the context of cyber physical protection of critical Internet infrastructure. The basis for this research is a specialized (and undoubtedly incomplete) taxonomy of Wi-Fi attacks and their adaptations to existing countermeasures and protocol revisions. Ultimately, this article aims to provide a clearer picture of how and why wireless protection protocols and encryption must achieve a more scientific basis for detecting and preventing such attacks.

  7. 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

  8. 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

  9. 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.

  10. Non-line-of-sight underwater optical wireless communication network.

    PubMed

    Arnon, Shlomi; Kedar, Debbie

    2009-03-01

    The growing need for ocean observation systems has stimulated considerable interest within the research community in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. Sensors and ad hoc sensor networks are the emerging tools for performing extensive data-gathering operations on land, and solutions in the subsea setting are being sought. Efficient communication from the sensors and within the network is critical, but the underwater environment is extremely challenging. Addressing the special features of underwater wireless communication in sensor networks, we propose a novel non-line-of-sight network concept in which the link is implemented by means of back-reflection of the propagating optic signal at the ocean-air interface and derive a mathematical model of the channel. Point-to-multipoint links can be achieved in an energy efficient manner and broadcast broadband communications, such as video transmissions, can be executed. We show achievable bit error rates as a function of sensor node separation and demonstrate the feasibility of this concept using state-of-the-art silicon photomultiplier detectors.

  11. Flexible quality of service model for wireless body area sensor networks.

    PubMed

    Liao, Yangzhe; Leeson, Mark S; Higgins, Matthew D

    2016-03-01

    Wireless body area sensor networks (WBASNs) are becoming an increasingly significant breakthrough technology for smart healthcare systems, enabling improved clinical decision-making in daily medical care. Recently, radio frequency ultra-wideband technology has developed substantially for physiological signal monitoring due to its advantages such as low-power consumption, high transmission data rate, and miniature antenna size. Applications of future ubiquitous healthcare systems offer the prospect of collecting human vital signs, early detection of abnormal medical conditions, real-time healthcare data transmission and remote telemedicine support. However, due to the technical constraints of sensor batteries, the supply of power is a major bottleneck for healthcare system design. Moreover, medium access control (MAC) needs to support reliable transmission links that allow sensors to transmit data safely and stably. In this Letter, the authors provide a flexible quality of service model for ad hoc networks that can support fast data transmission, adaptive schedule MAC control, and energy efficient ubiquitous WBASN networks. Results show that the proposed multi-hop communication ad hoc network model can balance information packet collisions and power consumption. Additionally, wireless communications link in WBASNs can effectively overcome multi-user interference and offer high transmission data rates for healthcare systems.

  12. 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.

  13. 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

  14. Wireless Networks: New Meaning to Ubiquitous Computing.

    ERIC Educational Resources Information Center

    Drew, Wilfred, Jr.

    2003-01-01

    Discusses the use of wireless technology in academic libraries. Topics include wireless networks; standards (IEEE 802.11); wired versus wireless; why libraries implement wireless technology; wireless local area networks (WLANs); WLAN security; examples of wireless use at Indiana State University and Morrisville College (New York); and useful…

  15. Routing to preserve energy in wireless networks

    NASA Astrophysics Data System (ADS)

    Block, Frederick J., IV

    increase energy consumption. We investigate the effects of time-varying interference on the lifetime of ad hoc networks. It is shown that there is a tradeoff between packet delay and node lifetime. We show that it is possible to design the system to perform well under a wide variety of channel conditions.

  16. Wireless Sensor Networks: Monitoring and Control

    SciTech Connect

    Hastbacka, Mildred; Ponoum, Ratcharit; Bouza, Antonio

    2013-05-31

    The article discusses wireless sensor technologies for building energy monitoring and control. This article, also, addresses wireless sensor networks as well as benefits and challenges of using wireless sensors. The energy savings and market potential of wireless sensors are reviewed.

  17. Low-Power Direct-Sequence Spread-Spectrum Modem Architecture for Distributed Wireless Sensor Networks

    SciTech Connect

    Chien, C; Elgorriaga, I; McConaghy, C

    2001-07-03

    Emerging CMOS and MEMS technologies enable the implementation of a large number of wireless distributed microsensors that can be easily and rapidly deployed to form highly redundant, self-configuring, and ad hoc sensor networks. To facilitate ease of deployment, these sensors should operate on battery for extended periods of time. A particular challenge in maintaining extended battery lifetime lies in achieving communications with low power. This paper presents a direct-sequence spread-spectrum modem architecture that provides robust communications for wireless sensor networks while dissipating very low power. The modem architecture has been verified in an FPGA implementation that dissipates only 33 mW for both transmission and reception. The implementation can be easily mapped to an ASIC technology, with an estimated power performance of less than 1 mW.

  18. 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.

  19. Views of wireless network systems.

    SciTech Connect

    Young, William Frederick; Duggan, David Patrick

    2003-10-01

    Wireless networking is becoming a common element of industrial, corporate, and home networks. Commercial wireless network systems have become reliable, while the cost of these solutions has become more affordable than equivalent wired network solutions. The security risks of wireless systems are higher than wired and have not been studied in depth. This report starts to bring together information on wireless architectures and their connection to wired networks. We detail information contained on the many different views of a wireless network system. The method of using multiple views of a system to assist in the determination of vulnerabilities comes from the Information Design Assurance Red Team (IDART{trademark}) Methodology of system analysis developed at Sandia National Laboratories.

  20. Wireless local area network security.

    PubMed

    Bergeron, Bryan P

    2004-01-01

    Wireless local area networks (WLANs) are increasingly popular in clinical settings because they facilitate the use of wireless PDAs, laptops, and other pervasive computing devices at the point of care. However, because of the relative immaturity of wireless network technology and evolving standards, WLANs, if improperly configured, can present significant security risks. Understanding the security limitations of the technology and available fixes can help minimize the risks of clinical data loss and maintain compliance with HIPAA guidelines.

  1. 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

  2. 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…

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  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. An Efficient Distributed Algorithm for Constructing Spanning Trees in Wireless Sensor Networks

    PubMed Central

    Lachowski, Rosana; Pellenz, Marcelo E.; Penna, Manoel C.; Jamhour, Edgard; Souza, Richard D.

    2015-01-01

    Monitoring and data collection are the two main functions in wireless sensor networks (WSNs). Collected data are generally transmitted via multihop communication to a special node, called the sink. While in a typical WSN, nodes have a sink node as the final destination for the data traffic, in an ad hoc network, nodes need to communicate with each other. For this reason, routing protocols for ad hoc networks are inefficient for WSNs. Trees, on the other hand, are classic routing structures explicitly or implicitly used in WSNs. In this work, we implement and evaluate distributed algorithms for constructing routing trees in WSNs described in the literature. After identifying the drawbacks and advantages of these algorithms, we propose a new algorithm for constructing spanning trees in WSNs. The performance of the proposed algorithm and the quality of the constructed tree were evaluated in different network scenarios. The results showed that the proposed algorithm is a more efficient solution. Furthermore, the algorithm provides multiple routes to the sensor nodes to be used as mechanisms for fault tolerance and load balancing. PMID:25594593

  10. 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.

  11. 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.

  12. Intrusion Detection and Forensics for Self-Defending Wireless Networks

    DTIC Science & Technology

    2012-12-01

    ICNP), Nov. 2007. 5. Yao Zhao, Yan Chen, Bo Li, and Qian Zhang, Hop ID: A Virtual Coordinate based Routing for Sparse Mobile Ad Hoc Networks, in...Liu, Hongbo Zhao, Kai Chen and Yan Chen, " DISCO : Memory Efficient and Accurate Flow Statistics for Network Measurement", in the Proc. of IEEE ICDCS

  13. 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...

  14. 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...

  15. 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…

  16. Wireless sensor network

    NASA Astrophysics Data System (ADS)

    Perotti, Jose M.; Lucena, Angel R.; Mullenix, Pamela A.; Mata, Carlos T.

    2006-05-01

    Current and future requirements of aerospace sensors and transducers demand the design and development of a new family of sensing devices, with emphasis on reduced weight, power consumption, and physical size. This new generation of sensors and transducers will possess a certain degree of intelligence in order to provide the end user with critical data in a more efficient manner. Communication between networks of traditional or next-generation sensors can be accomplished by a Wireless Sensor Network (WSN) developed by NASA's Instrumentation Branch and ASRC Aerospace Corporation at Kennedy Space Center (KSC), consisting of at least one central station and several remote stations and their associated software. The central station is application-dependent and can be implemented on different computer hardware, including industrial, handheld, or PC-104 single-board computers, on a variety of operating systems: embedded Windows, Linux, VxWorks, etc. The central stations and remote stations share a similar radio frequency (RF) core module hardware that is modular in design. The main components of the remote stations are an RF core module, a sensor interface module, batteries, and a power management module. These modules are stackable, and a common bus provides the flexibility to stack other modules for additional memory, increased processing, etc. WSN can automatically reconfigure to an alternate frequency if interference is encountered during operation. In addition, the base station will autonomously search for a remote station that was perceived to be lost, using relay stations and alternate frequencies. Several wireless remote-station types were developed and tested in the laboratory to support different sensing technologies, such as resistive temperature devices, silicon diodes, strain gauges, pressure transducers, and hydrogen leak detectors.

  17. Next Generation RFID-Based Medical Service Management System Architecture in Wireless Sensor Network

    NASA Astrophysics Data System (ADS)

    Tolentino, Randy S.; Lee, Kijeong; Kim, Yong-Tae; Park, Gil-Cheol

    Radio Frequency Identification (RFID) and Wireless Sensor Network (WSN) are two important wireless technologies that have wide variety of applications and provide unlimited future potentials most especially in healthcare systems. RFID is used to detect presence and location of objects while WSN is used to sense and monitor the environment. Integrating RFID with WSN not only provides identity and location of an object but also provides information regarding the condition of the object carrying the sensors enabled RFID tag. However, there isn't any flexible and robust communication infrastructure to integrate these devices into an emergency care setting. An efficient wireless communication substrate for medical devices that addresses ad hoc or fixed network formation, naming and discovery, transmission efficiency of data, data security and authentication, as well as filtration and aggregation of vital sign data need to be study and analyze. This paper proposed an efficient next generation architecture for RFID-based medical service management system in WSN that possesses the essential elements of each future medical application that are integrated with existing medical practices and technologies in real-time, remote monitoring, in giving medication, and patient status tracking assisted by embedded wearable wireless sensors which are integrated in wireless sensor network.

  18. 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.

  19. A Sensible Approach to Wireless Networking.

    ERIC Educational Resources Information Center

    Ahmed, S. Faruq

    2002-01-01

    Discusses radio frequency (R.F.) wireless technology, including industry standards, range (coverage) and throughput (data rate), wireless compared to wired networks, and considerations before embarking on a large-scale wireless project. (EV)

  20. Breaking Free with Wireless Networks.

    ERIC Educational Resources Information Center

    Fleischman, John

    2002-01-01

    Discusses wireless local area networks (LANs) which typically consist of laptop computers that connect to fixed access points via infrared or radio signals. Topics include wide area networks; personal area networks; problems, including limitations of available bandwidth, interference, and security concerns; use in education; interoperability;…

  1. 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

  2. Game-theoretic approach for improving cooperation in wireless multihop networks.

    PubMed

    Ng, See-Kee; Seah, Winston K G

    2010-06-01

    Traditional networks are built on the assumption that network entities cooperate based on a mandatory network communication semantic to achieve desirable qualities such as efficiency and scalability. Over the years, this assumption has been eroded by the emergence of users that alter network behavior in a way to benefit themselves at the expense of others. At one extreme, a malicious user/node may eavesdrop on sensitive data or deliberately inject packets into the network to disrupt network operations. The solution to this generally lies in encryption and authentication. In contrast, a rational node acts only to achieve an outcome that he desires most. In such a case, cooperation is still achievable if the outcome is to the best interest of the node. The node misbehavior problem would be more pronounced in multihop wireless networks like mobile ad hoc and sensor networks, which are typically made up of wireless battery-powered devices that must cooperate to forward packets for one another. However, cooperation may be hard to maintain as it consumes scarce resources such as bandwidth, computational power, and battery power. This paper applies game theory to achieve collusive networking behavior in such network environments. In this paper, pricing, promiscuous listening, and mass punishments are avoided altogether. Our model builds on recent work in the field of Economics on the theory of imperfect private monitoring for the dynamic Bertrand oligopoly, and adapts it to the wireless multihop network. The model derives conditions for collusive packet forwarding, truthful routing broadcasts, and packet acknowledgments under a lossy wireless multihop environment, thus capturing many important characteristics of the network layer and link layer in one integrated analysis that has not been achieved previously. We also provide a proof of the viability of the model under a theoretical wireless environment. Finally, we show how the model can be applied to design a generic

  3. 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.

  4. 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

  5. The Wireless Sensor Network (WSN) Based Coal Ash Impoundments Safety Monitoring System

    NASA Astrophysics Data System (ADS)

    Sun, E. J.; Nieto, A.; Zhang, X. K.

    2017-01-01

    Coal ash impoundments are inevitable production of the coal-fired power plants. All coal ash impoundments in North Carolina USA that tested for groundwater contamination are leaking toxic heavy metals and other pollutants. Coal ash impoundments are toxic sources of dangerous pollutants that pose a danger to human and environmental health if the toxins spread to adjacent surface waters and drinking water wells. Coal ash impoundments failures accidents resulted in serious water contamination along with toxic heavy metals. To improve the design and stability of coal ash impoundments, the Development of a Coal Ash Impoundment Safety Monitoring System (CAISM) was proposed based on the implementation of a wireless sensor network (WSN) with the ability to monitor the stability of coal ash impoundments, water level, and saturation levels on-demand and remotely. The monitoring system based on a robust Ad-hoc network could be adapted to different safety conditions.

  6. Adaptive Protocols for Mobile Wireless Networks

    DTIC Science & Technology

    2005-12-22

    frequency-hop wireless networks," International Journal of Wireless Information Networks , vol. 11, no. 3, pp. 147-159, July 2004. [PRW04c] M. B. Pursley...efficient routing of multimedia traffic in frequency-hop packet radio networks," submitted for publication in the International Journal of Wireless Information Networks , August

  7. Monitoring Churn in Wireless Networks

    NASA Astrophysics Data System (ADS)

    Holzer, Stephan; Pignolet, Yvonne Anne; Smula, Jasmin; Wattenhofer, Roger

    Wireless networks often experience a significant amount of churn, the arrival and departure of nodes. In this paper we propose a distributed algorithm for single-hop networks that detects churn and is resilient to a worst-case adversary. The nodes of the network are notified about changes quickly, in asymptotically optimal time up to an additive logarithmic overhead. We establish a trade-off between saving energy and minimizing the delay until notification for single- and multi-channel networks.

  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. Wi-fi walkman: a wireless handheld that shares and recommends music on peer-to-peer networks

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Reinders, Marcel J.; Pouwelse, Johan; Lagendijk, Reginald L.

    2005-03-01

    The Wi-Fi walkman is a mobile multimedia application that we developed to investigate the technological and usability aspects of human-computer interaction with personalized, intelligent and context-aware wearable devices in peer-to-peer wireless environments such as the future home, office, or university campuses. It is a small handheld device with a wireless link that contains music content. Users carry their own walkman around and listen to music. All this music content is distributed in the peer-to-peer network and is shared using ad-hoc networking. The walkman naturally interacts with the users and users" interest with each other in a peer-to-peer environment. Without annoying interactions, it can learn the users" music interest/taste and consequently provide personalized music recommendation according to the current situated context and user"s interest.

  12. 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

  13. Bio-Mimic Optimization Strategies in Wireless Sensor Networks: A Survey

    PubMed Central

    Adnan, Md. Akhtaruzzaman; Razzaque, Mohammd Abdur; Ahmed, Ishtiaque; Isnin, Ismail Fauzi

    2014-01-01

    For the past 20 years, many authors have focused their investigations on wireless sensor networks. Various issues related to wireless sensor networks such as energy minimization (optimization), compression schemes, self-organizing network algorithms, routing protocols, quality of service management, security, energy harvesting, etc., have been extensively explored. The three most important issues among these are energy efficiency, quality of service and security management. To get the best possible results in one or more of these issues in wireless sensor networks optimization is necessary. Furthermore, in number of applications (e.g., body area sensor networks, vehicular ad hoc networks) these issues might conflict and require a trade-off amongst them. Due to the high energy consumption and data processing requirements, the use of classical algorithms has historically been disregarded. In this context contemporary researchers started using bio-mimetic strategy-based optimization techniques in the field of wireless sensor networks. These techniques are diverse and involve many different optimization algorithms. As far as we know, most existing works tend to focus only on optimization of one specific issue of the three mentioned above. It is high time that these individual efforts are put into perspective and a more holistic view is taken. In this paper we take a step in that direction by presenting a survey of the literature in the area of wireless sensor network optimization concentrating especially on the three most widely used bio-mimetic algorithms, namely, particle swarm optimization, ant colony optimization and genetic algorithm. In addition, to stimulate new research and development interests in this field, open research issues, challenges and future research directions are highlighted. PMID:24368702

  14. Bio-mimic optimization strategies in wireless sensor networks: a survey.

    PubMed

    Adnan, Md Akhtaruzzaman; Abdur Razzaque, Mohammd; Ahmed, Ishtiaque; Isnin, Ismail Fauzi

    2013-12-24

    For the past 20 years, many authors have focused their investigations on wireless sensor networks. Various issues related to wireless sensor networks such as energy minimization (optimization), compression schemes, self-organizing network algorithms, routing protocols, quality of service management, security, energy harvesting, etc., have been extensively explored. The three most important issues among these are energy efficiency, quality of service and security management. To get the best possible results in one or more of these issues in wireless sensor networks optimization is necessary. Furthermore, in number of applications (e.g., body area sensor networks, vehicular ad hoc networks) these issues might conflict and require a trade-off amongst them. Due to the high energy consumption and data processing requirements, the use of classical algorithms has historically been disregarded. In this context contemporary researchers started using bio-mimetic strategy-based optimization techniques in the field of wireless sensor networks. These techniques are diverse and involve many different optimization algorithms. As far as we know, most existing works tend to focus only on optimization of one specific issue of the three mentioned above. It is high time that these individual efforts are put into perspective and a more holistic view is taken. In this paper we take a step in that direction by presenting a survey of the literature in the area of wireless sensor network optimization concentrating especially on the three most widely used bio-mimetic algorithms, namely, particle swarm optimization, ant colony optimization and genetic algorithm. In addition, to stimulate new research and development interests in this field, open research issues, challenges and future research directions are highlighted.

  15. Evolutionary games in wireless networks.

    PubMed

    Tembine, Hamidou; Altman, Eitan; El-Azouzi, Rachid; Hayel, Yezekael

    2010-06-01

    We consider a noncooperative interaction among a large population of mobiles that interfere with each other through many local interactions. The first objective of this paper is to extend the evolutionary game framework to allow an arbitrary number of mobiles that are involved in a local interaction. We allow for interactions between mobiles that are not necessarily reciprocal. We study 1) multiple-access control in a slotted Aloha-based wireless network and 2) power control in wideband code-division multiple-access wireless networks. We define and characterize the equilibrium (called evolutionarily stable strategy) for these games and study the influence of wireless channels and pricing on the evolution of dynamics and the equilibrium.

  16. 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

  17. Gigabit Wireless for Network Connectivity

    ERIC Educational Resources Information Center

    Schoedel, Eric

    2009-01-01

    Uninterrupted, high-bandwidth network connectivity is crucial for higher education. Colleges and universities increasingly adopt gigabit wireless solutions because of their fiber-equivalent performance, quick implementation, and significant return on investment. For just those reasons, Rush University Medical Center switched from free space optics…

  18. Reliable Wireless Broadcast with Linear Network Coding for Multipoint-to-Multipoint Real-Time Communications

    NASA Astrophysics Data System (ADS)

    Kondo, Yoshihisa; Yomo, Hiroyuki; Yamaguchi, Shinji; Davis, Peter; Miura, Ryu; Obana, Sadao; Sampei, Seiichi

    This paper proposes multipoint-to-multipoint (MPtoMP) real-time broadcast transmission using network coding for ad-hoc networks like video game networks. We aim to achieve highly reliable MPtoMP broadcasting using IEEE 802.11 media access control (MAC) that does not include a retransmission mechanism. When each node detects packets from the other nodes in a sequence, the correctly detected packets are network-encoded, and the encoded packet is broadcasted in the next sequence as a piggy-back for its native packet. To prevent increase of overhead in each packet due to piggy-back packet transmission, network coding vector for each node is exchanged between all nodes in the negotiation phase. Each user keeps using the same coding vector generated in the negotiation phase, and only coding information that represents which user signal is included in the network coding process is transmitted along with the piggy-back packet. Our simulation results show that the proposed method can provide higher reliability than other schemes using multi point relay (MPR) or redundant transmissions such as forward error correction (FEC). We also implement the proposed method in a wireless testbed, and show that the proposed method achieves high reliability in a real-world environment with a practical degree of complexity when installed on current wireless devices.

  19. 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.

  20. 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.

  1. 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.

  2. Underwater optical wireless communication network

    NASA Astrophysics Data System (ADS)

    Arnon, Shlomi

    2010-01-01

    The growing need for underwater observation and subsea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, biogeochemical, evolutionary, and ecological changes in the sea, ocean, and lake environments, and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. Models are presented for three kinds of optical wireless communication links: (a) a line-of-sight link, (b) a modulating retroreflector link, and (c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered light it was possible to mitigate this decrease in some cases. It is concluded from the analysis that a high-data-rate underwater optical wireless network is a feasible solution for emerging applications such as UUV-to-UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.

  3. Non-line-of-sight optical wireless sensor network operating in multiscattering channel

    NASA Astrophysics Data System (ADS)

    Kedar, Debbie; Arnon, Shlomi

    2006-11-01

    Networks of sensors are envisaged to be major participants in future data-gathering systems for civilian and military applications, including medical and environmental monitoring and surveillance, home security, agriculture, and industry. Typically, a very large number of miniature sensing and communicating nodes are distributed ad hoc at the location of interest, where they establish a network and wirelessly communicate sensed data either to one another or to a base station using various network topologies. The optical modality is a potential solution for the links, due to the small and lightweight hardware and low power consumption, as well as other special features. Notably, the backscattering of light by molecules and aerosols in the atmosphere can function as a vehicle of communication in a way similar to the deployment of numerous tiny reflecting mirrors. The scattering of light at solar-blind ultraviolet wavelengths is of particular interest since scattering by atmospheric particles is significant and ambient solar interference is minimal. In this paper we derive a mathematical model of a simple and low-cost non-line-of-sight (NLOS) optical wireless sensor network operating in the solar-blind ultraviolet spectral range. The viability and limitations of the internode link are evaluated and found to facilitate miniature operational sensor networks.

  4. Non-line-of-sight optical wireless sensor network operating in multiscattering channel.

    PubMed

    Kedar, Debbie; Arnon, Shlomi

    2006-11-20

    Networks of sensors are envisaged to be major participants in future data-gathering systems for civilian and military applications, including medical and environmental monitoring and surveillance, home security, agriculture, and industry. Typically, a very large number of miniature sensing and communicating nodes are distributed ad hoc at the location of interest, where they establish a network and wirelessly communicate sensed data either to one another or to a base station using various network topologies. The optical modality is a potential solution for the links, due to the small and lightweight hardware and low power consumption, as well as other special features. Notably, the backscattering of light by molecules and aerosols in the atmosphere can function as a vehicle of communication in a way similar to the deployment of numerous tiny reflecting mirrors. The scattering of light at solar-blind ultraviolet wavelengths is of particular interest since scattering by atmospheric particles is significant and ambient solar interference is minimal. In this paper we derive a mathematical model of a simple and low-cost non-line-of-sight (NLOS) optical wireless sensor network operating in the solar-blind ultraviolet spectral range. The viability and limitations of the internode link are evaluated and found to facilitate miniature operational sensor networks.

  5. Ultra-wideband radar sensors and networks

    DOEpatents

    Leach, Jr., Richard R; Nekoogar, Faranak; Haugen, Peter C

    2013-08-06

    Ultra wideband radar motion sensors strategically placed in an area of interest communicate with a wireless ad hoc network to provide remote area surveillance. Swept range impulse radar and a heart and respiration monitor combined with the motion sensor further improves discrimination.

  6. Energy efficient medium access protocol for wireless medical body area sensor networks.

    PubMed

    Omeni, O; Wong, A; Burdett, A J; Toumazou, C

    2008-12-01

    This paper presents a novel energy-efficient MAC Protocol designed specifically for wireless body area sensor networks (WBASN) focused towards pervasive healthcare applications. Wireless body area networks consist of wireless sensor nodes attached to the human body to monitor vital signs such as body temperature, activity or heart-rate. The network adopts a master-slave architecture, where the body-worn slave node periodically sends sensor readings to a central master node. Unlike traditional peer-to-peer wireless sensor networks, the nodes in this biomedical WBASN are not deployed in an ad hoc fashion. Joining a network is centrally managed and all communications are single-hop. To reduce energy consumption, all the sensor nodes are in standby or sleep mode until the centrally assigned time slot. Once a node has joined a network, there is no possibility of collision within a cluster as all communication is initiated by the central node and is addressed uniquely to a slave node. To avoid collisions with nearby transmitters, a clear channel assessment algorithm based on standard listen-before-transmit (LBT) is used. To handle time slot overlaps, the novel concept of a wakeup fallback time is introduced. Using single-hop communication and centrally controlled sleep/wakeup times leads to significant energy reductions for this application compared to more ldquoflexiblerdquo network MAC protocols such as 802.11 or Zigbee. As duty cycle is reduced, the overall power consumption approaches the standby power. The protocol is implemented in hardware as part of the Sensiumtrade system-on-chip WBASN ASIC, in a 0.13- mum CMOS process.

  7. Implementation of Multiple Host Nodes in Wireless Sensing Node Network System for Landslide Monitoring

    NASA Astrophysics Data System (ADS)

    Abas, Faizulsalihin bin; Takayama, Shigeru

    2015-02-01

    This paper proposes multiple host nodes in Wireless Sensing Node Network System (WSNNS) for landslide monitoring. As landslide disasters damage monitoring system easily, one major demand in landslide monitoring is the flexibility and robustness of the system to evaluate the current situation in the monitored area. For various reasons WSNNS can provide an important contribution to reach that aim. In this system, acceleration sensors and GPS are deployed in sensing nodes. Location information by GPS, enable the system to estimate network topology and enable the system to perceive the location in emergency by monitoring the node mode. Acceleration sensors deployment, capacitate this system to detect slow mass movement that can lead to landslide occurrence. Once deployed, sensing nodes self-organize into an autonomous wireless ad hoc network. The measurement parameter data from sensing nodes is transmitted to Host System via host node and "Cloud" System. The implementation of multiple host nodes in Local Sensing Node Network System (LSNNS), improve risk- management of the WSNNS for real-time monitoring of landslide disaster.

  8. Wireless Sensor Networks Approach

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M.

    2003-01-01

    This viewgraph presentation provides information on hardware and software configurations for a network architecture for sensors. The hardware configuration uses a central station and remote stations. The software configuration uses the 'lost station' software algorithm. The presentation profiles a couple current examples of this network architecture in use.

  9. 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…

  10. 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.

  11. 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…

  12. Assessment of the 802.11g Wireless Protocol for Lunar Surface Communications

    NASA Technical Reports Server (NTRS)

    Chelmins, David T.; Bguyen, Hung D.; Foore, Lawrence R.

    2009-01-01

    Future lunar surface missions supporting the NASA Vision for Space Exploration will rely on wireless networks to transmit voice and data. The ad hoc network architecture is of particular interest since it does not require a complex infrastructure. In this report, we looked at data performance over an ad hoc network with varying distances between Apple AirPort wireless cards. We developed a testing program to transmit data packets at precise times and then monitored the receive time to characterize connection delay, packet loss, and data rate. Best results were received for wireless links of less than 75 ft, and marginally acceptable (25-percent) packet loss was received at 150 ft. It is likely that better results will be obtained on the lunar surface because of reduced radiofrequency interference; however, higher power transmitters or receivers will be needed for significant performance gains.

  13. 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…

  14. 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...

  15. Availability and End-to-end Reliability in Low Duty Cycle Multihop Wireless Sensor Networks.

    PubMed

    Suhonen, Jukka; Hämäläinen, Timo D; Hännikäinen, Marko

    2009-01-01

    A wireless sensor network (WSN) is an ad-hoc technology that may even consist of thousands of nodes, which necessitates autonomic, self-organizing and multihop operations. A typical WSN node is battery powered, which makes the network lifetime the primary concern. The highest energy efficiency is achieved with low duty cycle operation, however, this alone is not enough. WSNs are deployed for different uses, each requiring acceptable Quality of Service (QoS). Due to the unique characteristics of WSNs, such as dynamic wireless multihop routing and resource constraints, the legacy QoS metrics are not feasible as such. We give a new definition to measure and implement QoS in low duty cycle WSNs, namely availability and reliability. Then, we analyze the effect of duty cycling for reaching the availability and reliability. The results are obtained by simulations with ZigBee and proprietary TUTWSN protocols. Based on the results, we also propose a data forwarding algorithm suitable for resource constrained WSNs that guarantees end-to-end reliability while adding a small overhead that is relative to the packet error rate (PER). The forwarding algorithm guarantees reliability up to 30% PER.

  16. Addressing practical challenges in utility optimization of mobile wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Eswaran, Sharanya; Misra, Archan; La Porta, Thomas; Leung, Kin

    2008-04-01

    This paper examines the practical challenges in the application of the distributed network utility maximization (NUM) framework to the problem of resource allocation and sensor device adaptation in a mission-centric wireless sensor network (WSN) environment. By providing rich (multi-modal), real-time information about a variety of (often inaccessible or hostile) operating environments, sensors such as video, acoustic and short-aperture radar enhance the situational awareness of many battlefield missions. Prior work on the applicability of the NUM framework to mission-centric WSNs has focused on tackling the challenges introduced by i) the definition of an individual mission's utility as a collective function of multiple sensor flows and ii) the dissemination of an individual sensor's data via a multicast tree to multiple consuming missions. However, the practical application and performance of this framework is influenced by several parameters internal to the framework and also by implementation-specific decisions. This is made further complex due to mobile nodes. In this paper, we use discrete-event simulations to study the effects of these parameters on the performance of the protocol in terms of speed of convergence, packet loss, and signaling overhead thereby addressing the challenges posed by wireless interference and node mobility in ad-hoc battlefield scenarios. This study provides better understanding of the issues involved in the practical adaptation of the NUM framework. It also helps identify potential avenues of improvement within the framework and protocol.

  17. 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

  18. 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.

  19. Wireless Communications. Wireless Network Integration Technology: MIRAI Architecture for Heterogeneous Network

    NASA Astrophysics Data System (ADS)

    Mizuno, Mitsuhiko; Wu, Gang; Havinga, Paul J. M.

    2001-12-01

    One of the keywords that describe next generation wireless communications is "seamless." As part of the e-Japan Plan promoted by the Japanese Government, the MIRAI (Multimedia Integrated network by Radio Access Innovation) project has, as its goal, the development of new technologies to enable seamless integration of various wireless access systems for practical use by the year 2005. This paper describes a heterogeneous network architecture including a common tool, a common platform, and a common access. In particular, software-defined radio technologies are used to develop a multi-service user terminal to access different wireless networks. The common platform for various wireless networks is based on a wireless supporting IPv6 network. A basic access network, separated from other wireless access networks, is used as a means for wireless system discovery, signaling, and paging. A proof-concept experimental demonstration system will be available in March, 2002.

  20. Reliability of Wireless Sensor Networks

    PubMed Central

    Dâmaso, Antônio; Rosa, Nelson; Maciel, Paulo

    2014-01-01

    Wireless Sensor Networks (WSNs) consist of hundreds or thousands of sensor nodes with limited processing, storage, and battery capabilities. There are several strategies to reduce the power consumption of WSN nodes (by increasing the network lifetime) and increase the reliability of the network (by improving the WSN Quality of Service). However, there is an inherent conflict between power consumption and reliability: an increase in reliability usually leads to an increase in power consumption. For example, routing algorithms can send the same packet though different paths (multipath strategy), which it is important for reliability, but they significantly increase the WSN power consumption. In this context, this paper proposes a model for evaluating the reliability of WSNs considering the battery level as a key factor. Moreover, this model is based on routing algorithms used by WSNs. In order to evaluate the proposed models, three scenarios were considered to show the impact of the power consumption on the reliability of WSNs. PMID:25157553

  1. Tips for Implementing a Wireless Network

    ERIC Educational Resources Information Center

    Walery, Darrell

    2005-01-01

    This article provides a quick start guide to provide educators with the basic points to consider before installing a wireless network in the school. Since many school districts have already implemented wireless networks, there is a lot of information available online to assist in the process.

  2. Epidemic Propagation In Overlaid Wireless Networks

    SciTech Connect

    Yanmaz, Evsen

    2008-01-01

    Witb tbe emergence of computer worms tbat can spread over air interfaces, wireless ad boc and sensor networks can be vulnerable to node compromises even if the deployed network is not connected to the backbone. Depending on the physical topology of the wireless network, even a single infected node can compromise the whole network. In this work, epidemic (e.g., worm) propagation in a static wireless network is studied, where a number of inCected mobile nodes are injected over the existing network. It is shown that the epidemic spread threshold and size depend on the physical topology of the underlying static wireless network as well as the mobility model employed by the infected mobile nodes. More specifically, results show that in a Cully-connected static wirelessnctwork targeted attacks are more effective, wbereas Cor a random topology random attacks can be sufficient to compromise the whole network.

  3. Wireless sensor network: an aimless gadget or a necessary tool for natural hazards warning systems

    NASA Astrophysics Data System (ADS)

    Hloupis, George; Stavrakas, Ilias; Triantis, Dimos

    2010-05-01

    The purpose of the current study is to review the current technical and scientific state of wireless sensor networks (WSNs) with application on natural hazards. WSN have received great attention from the research community in the last few years, mainly due to the theoretical and practical efforts from challenges that led to mature solutions and adoption of standards, such as Bluetooth [2] and ZigBee [3]. Wireless technology solutions allows Micro-ElectroMechanical Systems sensors (MEMS) to be integrated (with all the necessary circuitry) to small wireless capable devices, the nodes. Available MEMS today include pressure, temperature, humidity, inertial and strain-gauge sensors as well as transducers for velocity, acceleration, vibration, flow position and inclination [4]. A WSN is composed by a large number of nodes which are deployed densely adjacent to the area under monitoring. Each node collects data which transmitted to a gateway. The main requirements that WSNs must fulfilled are quite different than those of ad-hoc networks. WSNs have to be self-organized (since the positions of individual nodes are not known in advance), they must present cooperative processing of tasks (where groups of nodes cooperate in order to provide the gathered data to the user), they require security mechanisms that are adaptive to monitoring conditions and all algorithms must be energy optimized. In this paper, the state of the art in hardware, software, algorithms and protocols for WSNs, focused on natural hazards, is surveyed. Architectures for WSNs are investigated along with their advantages and drawbacks. Available research prototypes as well as commercially proposed solutions that can be used for natural hazards monitoring and early warning systems are listed and classified. [1] I.F. Akyildiz, W. Su, Y. Sankarasubramaniam, E. Cayirci, Wireless sensor networks: a survey, Comput. Networks (Elsevier) 38 (4) (2002) 393-422. [2] Dursch, A.; Yen, D.C.; Shih, D.H. Bluetooth

  4. 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.

  5. 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.

  6. 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.

  7. The optimation of random network coding in wireless MESH networks

    NASA Astrophysics Data System (ADS)

    Pang, Chunjiang; Pan, Xikun

    2013-03-01

    In order to improve the efficiency of wireless mesh network transmission, this paper focused on the network coding technology. Using network coding can significantly increase the wireless mesh network's throughput, but it will inevitably increase the computational complexity to the network, and the traditional linear network coding algorithm requires the aware of the whole network topology, which is impossible in the ever-changing topology of wireless mesh networks. In this paper, we use a distributed network coding strategy: random network coding, which don't need to know the whole topology of the network. In order to decrease the computation complexity, this paper suggests an improved strategy for random network coding: Do not code the packets which bring no good to the whole transmission. In this paper, we list several situations which coding is not necessary. Simulation results show that applying these strategies can improve the efficiency of wireless mesh network transmission.

  8. A Game Theoretic Power Control Algorithm with Sequential Subchannel Nulling for Wireless Networks

    NASA Astrophysics Data System (ADS)

    Park, Jae Cheol; Kim, Yun Hee; Hong, Een Kee; Song, Iickho

    Based on game theory, a distributed power control algorithm with sequential subchannel nulling is proposed for ad-hoc networks. It is shown that the proposed method, by sharing subchannels appropriately according to the interference profiles, can reduce the power consumption of the network while satisfying the target rate of each link.

  9. Self-Configuration and Self-Optimization Process in Heterogeneous Wireless Networks

    PubMed Central

    Guardalben, Lucas; Villalba, Luis Javier García; Buiati, Fábio; Sobral, João Bosco Mangueira; Camponogara, Eduardo

    2011-01-01

    Self-organization in Wireless Mesh Networks (WMN) is an emergent research area, which is becoming important due to the increasing number of nodes in a network. Consequently, the manual configuration of nodes is either impossible or highly costly. So it is desirable for the nodes to be able to configure themselves. In this paper, we propose an alternative architecture for self-organization of WMN based on Optimized Link State Routing Protocol (OLSR) and the ad hoc on demand distance vector (AODV) routing protocols as well as using the technology of software agents. We argue that the proposed self-optimization and self-configuration modules increase the throughput of network, reduces delay transmission and network load, decreases the traffic of HELLO messages according to network’s scalability. By simulation analysis, we conclude that the self-optimization and self-configuration mechanisms can significantly improve the performance of OLSR and AODV protocols in comparison to the baseline protocols analyzed. PMID:22346584

  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. Wireless Security Within Hastily Formed Networks

    DTIC Science & Technology

    2006-09-01

    Fortress Management and Policy Server (MaPS) .................52 e. Newbury Networks WiFi Watchdog.......................................53 F. SUMMARY...Secrets of Wireless Hacking , the authors argue the improved data confidentiality and integrity may improve wireless security for those choosing to...Juniper Networks Steel Belted RADIUS Appliance HW+SW 2, 3 N/A N 2 Newbury Networks WiFi Watchdog HW+SW 1, 3 N N N/A X X Phoenix Technologies

  12. Analysis and Testing of Mobile Wireless Networks

    NASA Technical Reports Server (NTRS)

    Alena, Richard; Evenson, Darin; Rundquist, Victor; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Wireless networks are being used to connect mobile computing elements in more applications as the technology matures. There are now many products (such as 802.11 and 802.11b) which ran in the ISM frequency band and comply with wireless network standards. They are being used increasingly to link mobile Intranet into Wired networks. Standard methods of analyzing and testing their performance and compatibility are needed to determine the limits of the technology. This paper presents analytical and experimental methods of determining network throughput, range and coverage, and interference sources. Both radio frequency (BE) domain and network domain analysis have been applied to determine wireless network throughput and range in the outdoor environment- Comparison of field test data taken under optimal conditions, with performance predicted from RF analysis, yielded quantitative results applicable to future designs. Layering multiple wireless network- sooners can increase performance. Wireless network components can be set to different radio frequency-hopping sequences or spreading functions, allowing more than one sooner to coexist. Therefore, we ran multiple 802.11-compliant systems concurrently in the same geographical area to determine interference effects and scalability, The results can be used to design of more robust networks which have multiple layers of wireless data communication paths and provide increased throughput overall.

  13. On computer vision in wireless sensor networks.

    SciTech Connect

    Berry, Nina M.; Ko, Teresa H.

    2004-09-01

    Wireless sensor networks allow detailed sensing of otherwise unknown and inaccessible environments. While it would be beneficial to include cameras in a wireless sensor network because images are so rich in information, the power cost of transmitting an image across the wireless network can dramatically shorten the lifespan of the sensor nodes. This paper describe a new paradigm for the incorporation of imaging into wireless networks. Rather than focusing on transmitting images across the network, we show how an image can be processed locally for key features using simple detectors. Contrasted with traditional event detection systems that trigger an image capture, this enables a new class of sensors which uses a low power imaging sensor to detect a variety of visual cues. Sharing these features among relevant nodes cues specific actions to better provide information about the environment. We report on various existing techniques developed for traditional computer vision research which can aid in this work.

  14. Wireless Laptops and Local Area Networks.

    ERIC Educational Resources Information Center

    Tolson, Stephanie Diane

    2001-01-01

    Describes experiences at St. Louis Community College at Florissant Valley (Missouri) with the use of wireless technology and a local area network for library bibliographic instruction. Discusses faculty input and attitudes; technical challenges; and experiences at other community colleges that have found wireless connections more economical than…

  15. Vulnerability of Wireless Networks to Interception

    DTIC Science & Technology

    2004-01-01

    S. and Yoshida, S. (1995) Propagation measurements and models for wireless communications channels, IEEE Communications Magazine , 33, 1:42 − 49...Proceedings-H, 138,1:61-73. Pahlavan, K. (1995) Trends in Local Wireless Networks, IEEE Communications Magazine , 33, 3:88-95. Science

  16. 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

  17. 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.

  18. Availability Issues in Wireless Visual Sensor Networks

    PubMed Central

    Costa, Daniel G.; Silva, Ivanovitch; Guedes, Luiz Affonso; Vasques, Francisco; Portugal, Paulo

    2014-01-01

    Wireless visual sensor networks have been considered for a large set of monitoring applications related with surveillance, tracking and multipurpose visual monitoring. When sensors are deployed over a monitored field, permanent faults may happen during the network lifetime, reducing the monitoring quality or rendering parts or the entire network unavailable. In a different way from scalar sensor networks, camera-enabled sensors collect information following a directional sensing model, which changes the notions of vicinity and redundancy. Moreover, visual source nodes may have different relevancies for the applications, according to the monitoring requirements and cameras' poses. In this paper we discuss the most relevant availability issues related to wireless visual sensor networks, addressing availability evaluation and enhancement. Such discussions are valuable when designing, deploying and managing wireless visual sensor networks, bringing significant contributions to these networks. PMID:24526301

  19. 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...

  20. Sinkhole Avoidance Routing in Wireless Sensor Networks

    DTIC Science & Technology

    2011-05-09

    increases the overall data integrity and reliability of wireless sensor networks. Due to battery limitations of individual sensor nodes, many WSN...commanders in real time, reducing risk and saving lives. 2 Introduction A wireless sensor network, or WSN, refers to a group of small battery powered...a battery . Additionally, a sensor node can be fitted with actuators that allow it to generate power, move about its environment, or perform some

  1. 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

  2. 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.

  3. Intrusion detection and monitoring for wireless networks.

    SciTech Connect

    Thomas, Eric D.; Van Randwyk, Jamie A.; Lee, Erik J.; Stephano, Amanda; Tabriz, Parisa; Pelon, Kristen; McCoy, Damon (University of Colorado, Boulder); Lodato, Mark; Hemingway, Franklin; Custer, Ryan P.; Averin, Dimitry; Franklin, Jason; Kilman, Dominique Marie

    2005-11-01

    Wireless computer networks are increasing exponentially around the world. They are being implemented in both the unlicensed radio frequency (RF) spectrum (IEEE 802.11a/b/g) and the licensed spectrum (e.g., Firetide [1] and Motorola Canopy [2]). Wireless networks operating in the unlicensed spectrum are by far the most popular wireless computer networks in existence. The open (i.e., proprietary) nature of the IEEE 802.11 protocols and the availability of ''free'' RF spectrum have encouraged many producers of enterprise and common off-the-shelf (COTS) computer networking equipment to jump into the wireless arena. Competition between these companies has driven down the price of 802.11 wireless networking equipment and has improved user experiences with such equipment. The end result has been an increased adoption of the equipment by businesses and consumers, the establishment of the Wi-Fi Alliance [3], and widespread use of the Alliance's ''Wi-Fi'' moniker to describe these networks. Consumers use 802.11 equipment at home to reduce the burden of running wires in existing construction, facilitate the sharing of broadband Internet services with roommates or neighbors, and increase their range of ''connectedness''. Private businesses and government entities (at all levels) are deploying wireless networks to reduce wiring costs, increase employee mobility, enable non-employees to access the Internet, and create an added revenue stream to their existing business models (coffee houses, airports, hotels, etc.). Municipalities (Philadelphia; San Francisco; Grand Haven, MI) are deploying wireless networks so they can bring broadband Internet access to places lacking such access; offer limited-speed broadband access to impoverished communities; offer broadband in places, such as marinas and state parks, that are passed over by traditional broadband providers; and provide themselves with higher quality, more complete network coverage for use by emergency responders and other

  4. Traffic Management Algorithms in Wireless Sensor Networks

    DTIC Science & Technology

    2006-09-01

    pages 48–51, Los Angeles, February 2003. [4] Ian F. Akyildiz, Weilian Su, Yogesg Sankarasubramaniam, and Erdal Cayirci. A survey on sensor networks... Mehmet C. Vuran, B. Akan, and Ian F. Akyildiz. Spatio-temporal correlation: theory and applications for wireless sensor networks. Computer Networks

  5. Heterogeneous Wireless Sensor Network for Real Time Remote Monitoring of Sand Dynamics on Coastal Dunes

    NASA Astrophysics Data System (ADS)

    Pozzebon, Alessandro; Bove, Carmine; Cappelli, Irene; Alquini, Fernanda; Bertoni, Duccio; Sarti, Giovanni

    2016-10-01

    In this paper, the architecture of a heterogeneous Wireless Sensor Network (WSN) to be deployed on coastal sand dunes is described, the aim of which is to provide real time measurements of physical parameters to better define the sediment transport in connection with Aeolian processes. The WSN integrates different typologies of sensors and is provided with both local and remote connection. In particular, three different typologies of sensors are integrated in the network: a multilayer anemometric station, a sensor developed ad-hoc to measure the sand dune level and a sand collector capable of measuring the weight of trapped sand and its quantity. Each sensor node is made up at least of a ZigBee radio module that is able to transmit the data collected by the sensor at a distance of about 100 meters. While the sand level sensor and the sand collector are provided only with this transmission module, the anemometric station also integrates a microprocessor board in charge of data processing. A Gateway node provided with a GSM connection for remote data transmission and a Zigbee radio module for Local Area communication has also been developed. This node is in charge of collecting all the data packets sent by the Sensor Nodes and transmit them to a remote server through GPRS connection. A Web server has been set up to collect these packets and store them in a database. The proposed WSN can provide both a static and a dynamic framework of sand transport processes acting on coastal dunes.

  6. 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

  7. Wireless Sensor Networks for Ambient Assisted Living

    PubMed Central

    Aquino-Santos, Raúl; Martinez-Castro, Diego; Edwards-Block, Arthur; Murillo-Piedrahita, Andrés Felipe

    2013-01-01

    This paper introduces wireless sensor networks for Ambient Assisted Living as a proof of concept. Our workgroup has developed an arrhythmia detection algorithm that we evaluate in a closed space using a wireless sensor network to relay the information collected to where the information can be registered, monitored and analyzed to support medical decisions by healthcare providers. The prototype we developed is then evaluated using the TelosB platform. The proposed architecture considers very specific restrictions regarding the use of wireless sensor networks in clinical situations. The seamless integration of the system architecture enables both mobile node and network configuration, thus providing the versatile and robust characteristics necessary for real-time applications in medical situations. Likewise, this system architecture efficiently permits the different components of our proposed platform to interact efficiently within the parameters of this study. PMID:24351665

  8. Wireless Wide Area Networks for School Districts.

    ERIC Educational Resources Information Center

    Nair, Prakash

    This paper considers a basic question that many schools districts face in attempting to develop affordable, expandable district-wide computer networks that are resistant to obsolescence: Should these wide area networks (WANs) employ wireless technology, stick to venerable hard-wired solutions, or combine both. This publication explores the…

  9. Modeling IoT-based solutions using human-centric wireless sensor networks.

    PubMed

    Monares, Álvaro; Ochoa, Sergio F; Santos, Rodrigo; Orozco, Javier; Meseguer, Roc

    2014-08-25

    The Internet of Things (IoT) has inspired solutions that are already available for addressing problems in various application scenarios, such as healthcare, security, emergency support and tourism. However, there is no clear approach to modeling these systems and envisioning their capabilities at the design time. Therefore, the process of designing these systems is ad hoc and its real impact is evaluated once the solution is already implemented, which is risky and expensive. This paper proposes a modeling approach that uses human-centric wireless sensor networks to specify and evaluate models of IoT-based systems at the time of design, avoiding the need to spend time and effort on early implementations of immature designs. It allows designers to focus on the system design, leaving the implementation decisions for a next phase. The article illustrates the usefulness of this proposal through a running example, showing the design of an IoT-based solution to support the first responses during medium-sized or large urban incidents. The case study used in the proposal evaluation is based on a real train crash. The proposed modeling approach can be used to design IoT-based systems for other application scenarios, e.g., to support security operatives or monitor chronic patients in their homes.

  10. Modeling IoT-Based Solutions Using Human-Centric Wireless Sensor Networks

    PubMed Central

    Monares, Álvaro; Ochoa, Sergio F.; Santos, Rodrigo; Orozco, Javier; Meseguer, Roc

    2014-01-01

    The Internet of Things (IoT) has inspired solutions that are already available for addressing problems in various application scenarios, such as healthcare, security, emergency support and tourism. However, there is no clear approach to modeling these systems and envisioning their capabilities at the design time. Therefore, the process of designing these systems is ad hoc and its real impact is evaluated once the solution is already implemented, which is risky and expensive. This paper proposes a modeling approach that uses human-centric wireless sensor networks to specify and evaluate models of IoT-based systems at the time of design, avoiding the need to spend time and effort on early implementations of immature designs. It allows designers to focus on the system design, leaving the implementation decisions for a next phase. The article illustrates the usefulness of this proposal through a running example, showing the design of an IoT-based solution to support the first responses during medium-sized or large urban incidents. The case study used in the proposal evaluation is based on a real train crash. The proposed modeling approach can be used to design IoT-based systems for other application scenarios, e.g., to support security operatives or monitor chronic patients in their homes. PMID:25157549

  11. Flexible network wireless transceiver and flexible network telemetry transceiver

    SciTech Connect

    Brown, Kenneth D.

    2008-08-05

    A transceiver for facilitating two-way wireless communication between a baseband application and other nodes in a wireless network, wherein the transceiver provides baseband communication networking and necessary configuration and control functions along with transmitter, receiver, and antenna functions to enable the wireless communication. More specifically, the transceiver provides a long-range wireless duplex communication node or channel between the baseband application, which is associated with a mobile or fixed space, air, water, or ground vehicle or other platform, and other nodes in the wireless network or grid. The transceiver broadly comprises a communication processor; a flexible telemetry transceiver including a receiver and a transmitter; a power conversion and regulation mechanism; a diplexer; and a phased array antenna system, wherein these various components and certain subcomponents thereof may be separately enclosed and distributable relative to the other components and subcomponents.

  12. Dynamic Hop Service Differentiation Model for End-to-End QoS Provisioning in Multi-Hop Wireless Networks

    NASA Astrophysics Data System (ADS)

    Youn, Joo-Sang; Seok, Seung-Joon; Kang, Chul-Hee

    This paper presents a new QoS model for end-to-end service provisioning in multi-hop wireless networks. In legacy IEEE 802.11e based multi-hop wireless networks, the fixed assignment of service classes according to flow's priority at every node causes priority inversion problem when performing end-to-end service differentiation. Thus, this paper proposes a new QoS provisioning model called Dynamic Hop Service Differentiation (DHSD) to alleviate the problem and support effective service differentiation between end-to-end nodes. Many previous works for QoS model through the 802.11e based service differentiation focus on packet scheduling on several service queues with different service rate and service priority. Our model, however, concentrates on a dynamic class selection scheme, called Per Hop Class Assignment (PHCA), in the node's MAC layer, which selects a proper service class for each packet, in accordance with queue states and service requirement, in every node along the end-to-end route of the packet. The proposed QoS solution is evaluated using the OPNET simulator. The simulation results show that the proposed model outperforms both best-effort and 802.11e based strict priority service models in mobile ad hoc environments.

  13. Collaboration in a Wireless Grid Innovation Testbed by Virtual Consortium

    NASA Astrophysics Data System (ADS)

    Treglia, Joseph; Ramnarine-Rieks, Angela; McKnight, Lee

    This paper describes the formation of the Wireless Grid Innovation Testbed (WGiT) coordinated by a virtual consortium involving academic and non-academic entities. Syracuse University and Virginia Tech are primary university partners with several other academic, government, and corporate partners. Objectives include: 1) coordinating knowledge sharing, 2) defining key parameters for wireless grids network applications, 3) dynamically connecting wired and wireless devices, content and users, 4) linking to VT-CORNET, Virginia Tech Cognitive Radio Network Testbed, 5) forming ad hoc networks or grids of mobile and fixed devices without a dedicated server, 6) deepening understanding of wireless grid application, device, network, user and market behavior through academic, trade and popular publications including online media, 7) identifying policy that may enable evaluated innovations to enter US and international markets and 8) implementation and evaluation of the international virtual collaborative process.

  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. Ultra wideband technology for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Xiong, Weiming

    2011-08-01

    Wireless sensor networks (WSNs) have emerged as an important method for planetary surface exploration. To investigate the optimized wireless technology for WSNs, we summarized the key requirements of WSNs and justified ultra wideband (UWB) technology by comparing with other competitive wireless technologies. We also analyzed network topologies as well as physical and MAC layer designs of IEEE 802.15.4a standard, which adopted impulse radio UWB (IR-UWB) technology. Our analysis showed that IR-UWB-based 802.15.4a standard could enable robust communication, precise ranging, and heterogeneous networking for WSNs applications. The result of our present work implies that UWB-based WSNs can be applied to future planetary surface exploration.

  16. File Transfer with Erasure Coding over Wireless Sensor Networks

    DTIC Science & Technology

    2009-03-01

    27 1. Onion Networks JAVA FEC Library ..............................................27 2. SNAIL Server Modifications...internet router , or some other device, the average person today is using wireless devices on an increasingly regular basis. A small subset of wireless...from Onion Networks were extremely helpful during this research [5]. 2. Medium Access Control for Wireless Sensor Networks One of the realizations

  17. Wi-GIM system: a new wireless sensor network (WSN) for accurate ground instability monitoring

    NASA Astrophysics Data System (ADS)

    Mucchi, Lorenzo; Trippi, Federico; Schina, Rosa; Fornaciai, Alessandro; Gigli, Giovanni; Nannipieri, Luca; Favalli, Massimiliano; Marturia Alavedra, Jordi; Intrieri, Emanuele; Agostini, Andrea; Carnevale, Ennio; Bertolini, Giovanni; Pizziolo, Marco; Casagli, Nicola

    2016-04-01

    Landslides are among the most serious and common geologic hazards around the world. Their impact on human life is expected to increase in the next future as a consequence of human-induced climate change as well as the population growth in proximity of unstable slopes. Therefore, developing better performing technologies for monitoring landslides and providing local authorities with new instruments able to help them in the decision making process, is becoming more and more important. The recent progresses in Information and Communication Technologies (ICT) allow us to extend the use of wireless technologies in landslide monitoring. In particular, the developments in electronics components have permitted to lower the price of the sensors and, at the same time, to actuate more efficient wireless communications. In this work we present a new wireless sensor network (WSN) system, designed and developed for landslide monitoring in the framework of EU Wireless Sensor Network for Ground Instability Monitoring - Wi-GIM project (LIFE12 ENV/IT/001033). We show the preliminary performance of the Wi-GIM system after the first period of monitoring on the active Roncovetro Landslide and on a large subsiding area in the neighbourhood of Sallent village. The Roncovetro landslide is located in the province of Reggio Emilia (Italy) and moved an inferred volume of about 3 million cubic meters. Sallent village is located at the centre of the Catalan evaporitic basin in Spain. The Wi-GIM WSN monitoring system consists of three levels: 1) Master/Gateway level coordinates the WSN and performs data aggregation and local storage; 2) Master/Server level takes care of acquiring and storing data on a remote server; 3) Nodes level that is based on a mesh of peripheral nodes, each consisting in a sensor board equipped with sensors and wireless module. The nodes are located in the landslide ground perimeter and are able to create an ad-hoc WSN. The location of each sensor on the ground is

  18. Thermodynamics of Large-Scale Heterogeneous Wireless Networks

    DTIC Science & Technology

    2014-03-06

    David Tse, co-PIs: Piyush Gupta, Devavrat Shah In recent years, large wireless networks have become the architecture of choice in many emerging...of this project, we have applied the lessons we learnt about wireless networks to other types of networks such as power networks. More details below. I...transmit powers . II. SYNCHRONIZATION A key issue to enable relaying/multi-hopping in wireless networks is synchronization between different network nodes

  19. Quality of service for tactical wireless networks

    NASA Astrophysics Data System (ADS)

    Ordower, Rick; Newman, Nisha; Myrtle, Jeremy

    2010-04-01

    Applications resident on tactical wireless networks are levying increasing offered loads. Tradeoffs can be made between range and throughput, but the wireless network is destined to be considered a limitation in information transfer. If managed correctly, the network can be an intelligent aid in ensuring the right information gets to the right place at the right time. Over the last 5 years, SAIC has worked with Natick Soldier Center (NSRDEC) to provide reliable communication with guaranteed service quality for the dismounted soldier. The effort utilizes a series of tools to mark, shape, condense, fragment and persist information for congestion and corruption control. The critical aspect of the congestion control solution is accomplished by adaptively throttling lower priority information at the sending node before it gets pushed to the wireless realm. Of note is that the solution adapts through passive processes without control messages. The solution also implements compression of messages and images, along with fragmentation techniques to alleviate congestion. Information corruption is purely a radio phenomenon and cannot be overcome through cognitive solutions. However, the solution mitigates corruption through information persistence and reliable retransmission. The implemented solution, unlike Transport Control Protocol, is optimized for wireless networks and demonstrates reduction of added signaling traffic. Combined congestion and corruption techniques have demonstrated how soldiers can get the right information at the right time during high traffic loads or network segmentation.

  20. 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.

  1. Detailed OFDM Modeling in Network Simulation of Mobile Ad Hoc Networks

    DTIC Science & Technology

    2003-01-01

    Ptolemy II as the design environment, some of the widely used models of computation for control system design — continuous time...closer to reality. The Ptolemy approach is similar to the approach used in this thesis. Our method of integrating heterogeneous models to...errors by mapping it to a BER value. Notice that, the simulated receiver SINR from the model is used instead of the model BER because of the

  2. Wireless Network Communications Overview for Space Mission Operations

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W.

    2009-01-01

    The mission of the On-Board Wireless Working Group (WWG) is to serve as a general CCSDS focus group for intra-vehicle wireless technologies. The WWG investigates and makes recommendations pursuant to standardization of applicable wireless network protocols, ensuring the interoperability of independently developed wireless communication assets. This document presents technical background information concerning uses and applicability of wireless networking technologies for space missions. Agency-relevant driving scenarios, for which wireless network communications will provide a significant return-on-investment benefiting the participating international agencies, are used to focus the scope of the enclosed technical information.

  3. Research on a Queue Scheduling Algorithm in Wireless Communications Network

    NASA Astrophysics Data System (ADS)

    Yang, Wenchuan; Hu, Yuanmei; Zhou, Qiancai

    This paper proposes a protocol QS-CT, Queue Scheduling Mechanism based on Multiple Access in Ad hoc net work, which adds queue scheduling mechanism to RTS-CTS-DATA using multiple access protocol. By endowing different queues different scheduling mechanisms, it makes networks access to the channel much more fairly and effectively, and greatly enhances the performance. In order to observe the final performance of the network with QS-CT protocol, we simulate it and compare it with MACA/C-T without QS-CT protocol. Contrast to MACA/C-T, the simulation result shows that QS-CT has greatly improved the throughput, delay, rate of packets' loss and other key indicators.

  4. Wireless Network Security Vulnerabilities and Concerns

    NASA Astrophysics Data System (ADS)

    Mushtaq, Ahmad

    The dilemma of cyber communications insecurity has existed all the times since the beginning of the network communications. The problems and concerns of unauthorized access and hacking has existed form the time of introduction of world wide web communication and Internet's expansion for popular use in 1990s, and has remained till present time as one of the most important issues. The wireless network security is no exception. Serious and continuous efforts of investigation, research and development has been going on for the last several decades to achieve the goal of provision of 100 percent or full proof security for all the protocols of networking architectures including the wireless networking. Some very reliable and robust strategies have been developed and deployed which has made network communications more and more secure. However, the most desired goal of complete security has yet to see the light of the day. The latest Cyber War scenario, reported in the media of intrusion and hacking of each other's defense and secret agencies between the two super powers USA and China has further aggravated the situation. This sort of intrusion by hackers between other countries such as India and Pakistan, Israel and Middle East countries has also been going on and reported in the media frequently. The paper reviews and critically examines the strategies already in place, for wired network. Wireless Network Security and also suggests some directions and strategies for more robust aspects to be researched and deployed.

  5. Implementation of Wireless Networks in Rural Areas

    DTIC Science & Technology

    2004-06-01

    access, public telephone service and fax lines to certain rural areas ( Unimas , 2004). 2. Advantages of Wireless Networking in Rural Areas With...648). Kuching. UNIMAS (2004). e-Bario Homepage: Strategy. Retrieved April 5, 2004, from http://www.unimas.my/ebario/Strategy_index.htm Cisco

  6. OCP: Opportunistic Carrier Prediction for Wireless Networks

    DTIC Science & Technology

    2008-08-01

    Many protocols have been proposed for medium access control in wireless networks. MACA [13], MACAW [3], and FAMA [8] are the earlier proposals for...world performance of carrier sense. In Proceedings of ACM SIGCOMM E-WIND Workshop, 2005. [13] P. Karn. MACA : A new channel access method for packet radio

  7. Secure Wireless Networking at Simon Fraser University.

    ERIC Educational Resources Information Center

    Johnson, Worth

    2003-01-01

    Describes the wireless local area network (WLAN) at Simon Fraser University, British Columbia, Canada. Originally conceived to address computing capacity and reduce university computer space demands, the WLAN has provided a seamless computing environment for students and solved a number of other campus problems as well. (SLD)

  8. Object Tracking Using Wireless Sensor Networks

    DTIC Science & Technology

    2005-09-01

    wireless networks weaknesses analogous to the power-consumptions and message-delay concerns of current systems. Medium Access Control (MAC) techniques ...... techniques and routing, like “an asymmetric many-to-one data flow” (Carle & Simplot- Ryl, 2004) to communicate. Nodes’ characteristics (size, lifetime

  9. Clock Synchronization for Multihop Wireless Sensor Networks

    ERIC Educational Resources Information Center

    Solis Robles, Roberto

    2009-01-01

    In wireless sensor networks, more so generally than in other types of distributed systems, clock synchronization is crucial since by having this service available, several applications such as media access protocols, object tracking, or data fusion, would improve their performance. In this dissertation, we propose a set of algorithms to achieve…

  10. LON Technology in Wireless Sensor Networking Applications

    PubMed Central

    Miskowicz, Marek; Golanski, Ryszard

    2006-01-01

    In the paper a discussion on how to optimize LonWorks/EIA-709 sensor networking technology for wireless applications, in presented. Main solutions offered by Local Operating Networks (LON, LonWorks) platform attractive for wireless communication, that is, the send-on-delta concept and the sleep mode, are displayed. The predictive p-persistent CSMA MAC protocol constituting the heart of the communication capability of LON networks is analysed in detail. Next, the message services are described, and the analytical evaluation of delivery reliability is derived. Performance evaluation based on simulation results for unicast traffic is presented first. In order to highlight the robustness of the predictive CSMA to overload situations, the saturation performance for a general case load scenario including multicast transactions is reported. The methods of effective management of energy consumption in LonWorks networks are discussed. Finally, the LON design tradeoffs are summarized.

  11. Stabilizing Health Monitoring for Wireless Sensor Networks

    DTIC Science & Technology

    2006-02-01

    protocol as part of enabling a network health status service that is tightly integrated with a remotely accessible wireless sensor network testbed, Kansei ...tation on a heterogenous WSN testbed, Kansei , comprising hundreds of Motes (of multiple types, specifically XSMs and TMoteSkys), Stargates, and PCs...predicted by the analysis. It is also necessary for enabling a health monitoring service that is a crucial and tightly integrated component of Kansei

  12. Topological Analysis of Wireless Networks (TAWN)

    DTIC Science & Technology

    2016-05-31

    Michael American University Department of Mathematics and Statistics 4400 Massachusetts Ave NW Washington, DC 20016 N/A Defense Advanced Research...protocol, activity, and channel conditions can be associated to such a cell complex using a mathematical object called a sheaf. We leveraged the existing... mathematical literature on sheaves that describes how to draw global (network-wide) inferences from them. Wireless network, local homology, sheaf

  13. Distributed Estimation, Coding, and Scheduling in Wireless Visual Sensor Networks

    ERIC Educational Resources Information Center

    Yu, Chao

    2013-01-01

    In this thesis, we consider estimation, coding, and sensor scheduling for energy efficient operation of wireless visual sensor networks (VSN), which consist of battery-powered wireless sensors with sensing (imaging), computation, and communication capabilities. The competing requirements for applications of these wireless sensor networks (WSN)…

  14. Wireless Local Area Networks: The Next Evolutionary Step.

    ERIC Educational Resources Information Center

    Wodarz, Nan

    2001-01-01

    The Institute of Electrical and Electronics Engineers recently approved a high-speed wireless standard that enables devices from different manufacturers to communicate through a common backbone, making wireless local area networks more feasible in schools. Schools can now use wireless access points and network cards to provide flexible…

  15. 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…

  16. 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.

  17. 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…

  18. Potential uses of a wireless network in physical security systems.

    SciTech Connect

    Witzke, Edward L.

    2010-07-01

    Many possible applications requiring or benefiting from a wireless network are available for bolstering physical security and awareness at high security installations or facilities. These enhancements are not always straightforward and may require careful analysis, selection, tuning, and implementation of wireless technologies. In this paper, an introduction to wireless networks and the task of enhancing physical security is first given. Next, numerous applications of a wireless network are brought forth. The technical issues that arise when using a wireless network to support these applications are then discussed. Finally, a summary is presented.

  19. Channel models for wireless body area networks.

    PubMed

    Takizawa, Kenichi; Aoyagi, Akahiro; Takada, Jun-Ichi; Katayama, Norihiko; Yekeh, Kamya; Takehiko, Yazdandoost; Kohno, Kobayashi Ryuji

    2008-01-01

    Wireless patient monitoring using wearable sensors is a promising application. This paper provides stochastic channel models for wireless body area network (WBAN) on the human body. Parameters of the channel models are extracted from measured channel transfer functions (CTFs) in a hospital room. Measured frequency bands are selected so as to include permissible bands for WBAN; ultra wideband (UWB), the industry, science and medical (ISM) bands, and wireless medical telemetry system (WMTS) bands. As channel models, both a path loss model and a power delay profile (PDP) model are considered. But, even though path loss models are derived for the all frequency bands, PDP model is only for the UWB band due to the highly frequency selectiveness of UWB channels. The parameters extracted from the measurement results are summarized for each channel model.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Wireless Sensor Network Handles Image Data

    NASA Technical Reports Server (NTRS)

    2008-01-01

    To relay data from remote locations for NASA s Earth sciences research, Goddard Space Flight Center contributed to the development of "microservers" (wireless sensor network nodes), which are now used commercially as a quick and affordable means to capture and distribute geographical information, including rich sets of aerial and street-level imagery. NASA began this work out of a necessity for real-time recovery of remote sensor data. These microservers work much like a wireless office network, relaying information between devices. The key difference, however, is that instead of linking workstations within one office, the interconnected microservers operate miles away from one another. This attribute traces back to the technology s original use: The microservers were originally designed for seismology on remote glaciers and ice streams in Alaska, Greenland, and Antarctica-acquiring, storing, and relaying data wirelessly between ground sensors. The microservers boast three key attributes. First, a researcher in the field can establish a "managed network" of microservers and rapidly see the data streams (recovered wirelessly) on a field computer. This rapid feedback permits the researcher to reconfigure the network for different purposes over the course of a field campaign. Second, through careful power management, the microservers can dwell unsupervised in the field for up to 2 years, collecting tremendous amounts of data at a research location. The third attribute is the exciting potential to deploy a microserver network that works in synchrony with robotic explorers (e.g., providing ground truth validation for satellites, supporting rovers as they traverse the local environment). Managed networks of remote microservers that relay data unsupervised for up to 2 years can drastically reduce the costs of field instrumentation and data rec

  9. Formation And Maintenance of Self-Organizing Wireless Networks

    NASA Technical Reports Server (NTRS)

    Scott, Keith; Bambos, Nicholas

    1997-01-01

    There are numerous military, commercial, and scientific applications for mobile wireless networks which are able to self-Organize without recousre to any pre-existing infrastructure. We present the Self Organizing Wireless Adaptive Network protocol, a distributed networking protocol capable of managing such networks.

  10. Scalable Video Streaming in Wireless Mesh Networks for Education

    ERIC Educational Resources Information Center

    Liu, Yan; Wang, Xinheng; Zhao, Liqiang

    2011-01-01

    In this paper, a video streaming system for education based on a wireless mesh network is proposed. A wireless mesh network is a self-organizing, self-managing and reliable intelligent network, which allows educators to deploy a network quickly. Video streaming plays an important role in this system for multimedia data transmission. This new…

  11. Bridge monitoring using heterogeneous wireless sensor network

    NASA Astrophysics Data System (ADS)

    Haran, Shivan; Kher, Shubhalaxmi; Mehndiratta, Vandana

    2010-03-01

    Wireless sensor networks (WSN) are proving to be a good fit where real time monitoring of multiple physical parameters is required. In many applications such as structural health monitoring, patient data monitoring, traffic accident monitoring and analysis, sensor networks may involve interface with conventional P2P systems and it is challenging to handle heterogeneous network systems. Heterogeneous deployments will become increasingly prevalent as it allows for systems to seamlessly integrate and interoperate especially when it comes to applications involving monitoring of large infrastructures. Such networks may have wireless sensor network overlaid on a conventional computer network to pick up data from one distant location and carry out the analysis after relaying it over to another distant location. This paper discusses monitoring of bridges using WSN. As a test bed, a heterogeneous network of WSN and conventional P2P together with a combination of sensing devices (including vibration and strain) is to be used on a bridge model. Issues related to condition assessment of the bridge for situations including faults, overloads, etc., as well as analysis of network and system performance will be discussed. When conducted under controlled conditions, this is an important step towards fine tuning the monitoring system for recommendation of permanent mounting of sensors and collecting data that can help in the development of new methods for inspection and evaluation of bridges. The proposed model, design, and issues therein will be discussed, along with its implementation and results.

  12. 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

  13. Seamless wireless networking for video surveillance applications

    NASA Astrophysics Data System (ADS)

    Agrafiotis, D.; Chiew, T.-K.; Ferre, P.; Bull, David R.; Nix, A. R.; Doufexi, A.; Chung-How, J.; Nicholson, Didier

    2005-03-01

    The EU FP6 WCAM (Wireless Cameras and Audio-Visual Seamless Networking) project aims to study, develop and validate a wireless, seamless and secured end-to-end networked audio-visual system for video surveillance and multimedia distribution applications. This paper describes the video transmission aspects of the project, with contributions in the areas of H.264 video delivery over wireless LANs. The planned demonstrations under WCAM include the transmission of H.264 coded material over 802.11b/g networks with TCP/IP and UDP/IP being employed as the transport and network layers over unicast and multicast links. UDP based unicast and multicast transmissions pose the problem of packet erasures while TCP based transmission is associated with long delays and the need for a large jitter buffer. This paper presents measurement data that have been collected at the WCAM trial site along with analysis of the data, including characterisation of the channel conditions as well as recommendations on the optimal operating parameters for each of the above transmission scenarios (e.g. jitter buffer sizes, packet error rates, etc.). Recommendations for error resilient coding algorithms and packetisation strategies are made in order to moderate the effect of the observed packet erasures on the quality of the transmitted video. Advanced error concealment methods for masking the effects of packet erasures at the receiver/decoder are also described.

  14. Learning sensor models for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Ertin, Emre

    2007-04-01

    Sensor data generation is a key component of high fidelity design and testing of applications at scale. In addition to its utility in validation of applications and network services, it provides a theoretical basis for the design of algorithms for efficient sampling, compression and exfiltration of the sensor readings. Modeling of the environmental processes that gives rise to sensor readings is the core problem in physical sciences. Sensor modeling for wireless sensor networks combine the physics of signal generation and propagation with models of transducer saturation and fault models for hardware. In this paper we introduce a novel modeling technique for constructing probabilistic models for censored sensor readings. The model is an extension of the Gaussian process regression and applies to continuous valued readings subject to censoring. We illustrate the performance of the proposed technique in modeling wireless propagation between nodes of a wireless sensor network. The model can capture the non-isotropic nature of the propagation characteristics and utilizes the information from the packet reception failures. We use measured data set from the Kansei sensor network testbed using 802.15.4 radios.

  15. High fidelity wireless network evaluation for heterogeneous cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Ding, Lei; Sagduyu, Yalin; Yackoski, Justin; Azimi-Sadjadi, Babak; Li, Jason; Levy, Renato; Melodia, Tammaso

    2012-06-01

    We present a high fidelity cognitive radio (CR) network emulation platform for wireless system tests, measure- ments, and validation. This versatile platform provides the configurable functionalities to control and repeat realistic physical channel effects in integrated space, air, and ground networks. We combine the advantages of scalable simulation environment with reliable hardware performance for high fidelity and repeatable evaluation of heterogeneous CR networks. This approach extends CR design only at device (software-defined-radio) or lower-level protocol (dynamic spectrum access) level to end-to-end cognitive networking, and facilitates low-cost deployment, development, and experimentation of new wireless network protocols and applications on frequency- agile programmable radios. Going beyond the channel emulator paradigm for point-to-point communications, we can support simultaneous transmissions by network-level emulation that allows realistic physical-layer inter- actions between diverse user classes, including secondary users, primary users, and adversarial jammers in CR networks. In particular, we can replay field tests in a lab environment with real radios perceiving and learning the dynamic environment thereby adapting for end-to-end goals over distributed spectrum coordination channels that replace the common control channel as a single point of failure. CR networks offer several dimensions of tunable actions including channel, power, rate, and route selection. The proposed network evaluation platform is fully programmable and can reliably evaluate the necessary cross-layer design solutions with configurable op- timization space by leveraging the hardware experiments to represent the realistic effects of physical channel, topology, mobility, and jamming on spectrum agility, situational awareness, and network resiliency. We also provide the flexibility to scale up the test environment by introducing virtual radios and establishing seamless signal

  16. Wireless sensor networks in a maritime environment

    NASA Astrophysics Data System (ADS)

    Kavelaars, W.; Maris, M.

    2005-10-01

    In the recent years, there has been a lot of research on sensor networks and their applications. In particular for monitoring large and potentially hostile areas these networks have proven to be very useful. The technique of land-based sensor networks can be extrapolated to sensing buoys at sea or in harbors. This is a novel and intriguing addition to existing maritime monitoring systems. At TNO, much research effort has gone into developing sensor networks. In this paper, the TNOdes sensor network is presented. Its practical employability is demonstrated in a surveillance application deploying 50 nodes. The system is capable of tracking persons in a field, as would be the situation around a military compound. A camera-system is triggered by the sensors and zooms into the detected moving objects. It is described how this system could be modified to create a wireless buoys network. Typical applications of a wireless (and potentially mobile) buoy network are bay-area surveillance, mine detection, identification and ship protection.

  17. SITRUS: Semantic Infrastructure for Wireless Sensor Networks

    PubMed Central

    Bispo, Kalil A.; Rosa, Nelson S.; Cunha, Paulo R. F.

    2015-01-01

    Wireless sensor networks (WSNs) are made up of nodes with limited resources, such as processing, bandwidth, memory and, most importantly, energy. For this reason, it is essential that WSNs always work to reduce the power consumption as much as possible in order to maximize its lifetime. In this context, this paper presents SITRUS (semantic infrastructure for wireless sensor networks), which aims to reduce the power consumption of WSN nodes using ontologies. SITRUS consists of two major parts: a message-oriented middleware responsible for both an oriented message communication service and a reconfiguration service; and a semantic information processing module whose purpose is to generate a semantic database that provides the basis to decide whether a WSN node needs to be reconfigurated or not. In order to evaluate the proposed solution, we carried out an experimental evaluation to assess the power consumption and memory usage of WSN applications built atop SITRUS. PMID:26528974

  18. SITRUS: Semantic Infrastructure for Wireless Sensor Networks.

    PubMed

    Bispo, Kalil A; Rosa, Nelson S; Cunha, Paulo R F

    2015-10-29

    Wireless sensor networks (WSNs) are made up of nodes with limited resources, such as processing, bandwidth, memory and, most importantly, energy. For this reason, it is essential that WSNs always work to reduce the power consumption as much as possible in order to maximize its lifetime. In this context, this paper presents SITRUS (semantic infrastructure for wireless sensor networks), which aims to reduce the power consumption of WSN nodes using ontologies. SITRUS consists of two major parts: a message-oriented middleware responsible for both an oriented message communication service and a reconfiguration service; and a semantic information processing module whose purpose is to generate a semantic database that provides the basis to decide whether a WSN node needs to be reconfigurated or not. In order to evaluate the proposed solution, we carried out an experimental evaluation to assess the power consumption and memory usage of WSN applications built atop SITRUS.

  19. Mobile Assisted Security in Wireless Sensor Networks

    DTIC Science & Technology

    2015-08-03

    reduce to complexity of providing security in wireless sensor networks. We worked on mobile assisted key management to distribute keys using mobile... worked on mobile assisted key management to distribute keys using mobile robots and controlled path traversal where a robot has to prove the path...5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 5c. PROGRAM ELEMENT NUMBER 5b. GRANT NUMBER 5a. CONTRACT NUMBER Form Approved OMB NO

  20. Wireless Local Area Networks: Simulation and Analysis

    DTIC Science & Technology

    1998-06-01

    response, including the time for reviewing instruction, searching existing data sources , gathering and maintaining the data needed, and completing and...multiple paths that the electromagnetic waves travel (multi-path interference). This thesis presents two separate simulations. In the first, a realistic...examine the reliability of the wireless standard for the medium access control (MAC) layer, using CACI COMNET HJ network simulation software. This

  1. Defeating 802.11 Wireless Networks

    DTIC Science & Technology

    2008-06-01

    also known as an access point (AP). The AP is typically connected via a network cable to a router which is then connected to the internet. Wireless...layer messages. Application layer messages contain 39 as e-ma ta e, . . excessive end to end delays. Next, a e “ onion ” are preserved...intercepted frame is un-encapsulated. This step is synonymous to peeling away the layers of an onion to get to the application message. The layers of the

  2. Location Privacy Issues in Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Kůr, Jiří; Stetsko, Andriy

    We discuss location privacy issues in wireless sensor networks. We consider sensor nodes with more responsible roles and the need to protect locations of such nodes. Available countermeasures against various types of traffic analysis attacks are examined and their problems are identified. We do not propose new traffic analysis resistance technique. Instead, we draw attention to blanks in current situation and identify several open questions, which should be answered in order to ensure location privacy of nodes.

  3. 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.

  4. 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

  5. Wireless sensor network for monitoring soil moisture and weather conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless sensor network (WSN) was developed and deployed in three fields to monitor soil water status and collect weather data for irrigation scheduling. The WSN consists of soil-water sensors, weather sensors, wireless data loggers, and a wireless modem. Soil-water sensors were installed at three...

  6. Bidirectional QoS support for novelty detection applications based on hierarchical wireless sensor network model

    NASA Astrophysics Data System (ADS)

    Edwards, Mark; Hu, Fei; Kumar, Sunil

    2004-10-01

    The research on the Novelty Detection System (NDS) (called as VENUS) at the authors' universities has generated exciting results. For example, we can detect an abnormal behavior (such as cars thefts from the parking lot) from a series of video frames based on the cognitively motivated theory of habituation. In this paper, we would like to describe the implementation strategies of lower layer protocols for using large-scale Wireless Sensor Networks (WSN) to NDS with Quality-of-Service (QoS) support. Wireless data collection framework, consisting of small and low-power sensor nodes, provides an alternative mechanism to observe the physical world, by using various types of sensing capabilities that include images (and even videos using Panoptos), sound and basic physical measurements such as temperature. We do not want to lose any 'data query command' packets (in the downstream direction: sink-to-sensors) or have any bit-errors in them since they are so important to the whole sensor network. In the upstream direction (sensors-to-sink), we may tolerate the loss of some sensing data packets. But the 'interested' sensing flow should be assigned a higher priority in terms of multi-hop path choice, network bandwidth allocation, and sensing data packet generation frequency (we hope to generate more sensing data packet for that novel event in the specified network area). The focus of this paper is to investigate MAC-level Quality of Service (QoS) issue in Wireless Sensor Networks (WSN) for Novelty Detection applications. Although QoS has been widely studied in other types of networks including wired Internet, general ad hoc networks and mobile cellular networks, we argue that QoS in WSN has its own characteristics. In wired Internet, the main QoS parameters include delay, jitter and bandwidth. In mobile cellular networks, two most common QoS metrics are: handoff call dropping probability and new call blocking probability. Since the main task of WSN is to detect and report

  7. 47 CFR 27.1305 - Shared wireless broadband network.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... interoperable across public safety local and state agencies, jurisdictions, and geographic areas, and that... 47 Telecommunication 2 2011-10-01 2011-10-01 false Shared wireless broadband network. 27.1305... broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private...

  8. 47 CFR 27.1305 - Shared wireless broadband network.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... interoperable across public safety local and state agencies, jurisdictions, and geographic areas, and that... 47 Telecommunication 2 2010-10-01 2010-10-01 false Shared wireless broadband network. 27.1305... broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private...

  9. 47 CFR 27.1305 - Shared wireless broadband network.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... interoperable across public safety local and state agencies, jurisdictions, and geographic areas, and that... 47 Telecommunication 2 2012-10-01 2012-10-01 false Shared wireless broadband network. 27.1305... broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private...

  10. 47 CFR 90.1405 - Shared wireless broadband network.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... interoperable across public safety local and state agencies, jurisdictions, and geographic areas, and which... 47 Telecommunication 5 2012-10-01 2012-10-01 false Shared wireless broadband network. 90.1405... broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private...

  11. The Systems Librarian: Implementing Wireless Networks without Compromising Security

    ERIC Educational Resources Information Center

    Breeding, Marshall

    2005-01-01

    Many libraries are or soon will be offering Wi-Fi, also known as wireless networks. The largest perceived barriers to providing this service are concerns about security. The prime rule when deploying Wi-Fi is segregation, having a clear separation between a public wireless network and the rest of the library?s network. A number of devices can be…

  12. 47 CFR 90.1405 - Shared wireless broadband network.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... interoperable across public safety local and state agencies, jurisdictions, and geographic areas, and which... 47 Telecommunication 5 2011-10-01 2011-10-01 false Shared wireless broadband network. 90.1405... broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private...

  13. 47 CFR 90.1405 - Shared wireless broadband network.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... interoperable across public safety local and state agencies, jurisdictions, and geographic areas, and which... 47 Telecommunication 5 2010-10-01 2010-10-01 false Shared wireless broadband network. 90.1405... broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private...

  14. A Wireless Communications Laboratory on Cellular Network Planning

    ERIC Educational Resources Information Center

    Dawy, Z.; Husseini, A.; Yaacoub, E.; Al-Kanj, L.

    2010-01-01

    The field of radio network planning and optimization (RNPO) is central for wireless cellular network design, deployment, and enhancement. Wireless cellular operators invest huge sums of capital on deploying, launching, and maintaining their networks in order to ensure competitive performance and high user satisfaction. This work presents a lab…

  15. Wireless body sensor networks for health-monitoring applications.

    PubMed

    Hao, Yang; Foster, Robert

    2008-11-01

    Current wireless technologies, such as wireless body area networks and wireless personal area networks, provide promising applications in medical monitoring systems to measure specified physiological data and also provide location-based information, if required. With the increasing sophistication of wearable and implantable medical devices and their integration with wireless sensors, an ever-expanding range of therapeutic and diagnostic applications is being pursued by research and commercial organizations. This paper aims to provide a comprehensive review of recent developments in wireless sensor technology for monitoring behaviour related to human physiological responses. It presents background information on the use of wireless technology and sensors to develop a wireless physiological measurement system. A generic miniature platform and other available technologies for wireless sensors have been studied in terms of hardware and software structural requirements for a low-cost, low-power, non-invasive and unobtrusive system.

  16. NEURON: Enabling Autonomicity in Wireless Sensor Networks

    PubMed Central

    Zafeiropoulos, Anastasios; Gouvas, Panagiotis; Liakopoulos, Athanassios; Mentzas, Gregoris; Mitrou, Nikolas

    2010-01-01

    Future Wireless Sensor Networks (WSNs) will be ubiquitous, large-scale networks interconnected with the existing IP infrastructure. Autonomic functionalities have to be designed in order to reduce the complexity of their operation and management, and support the dissemination of knowledge within a WSN. In this paper a novel protocol for energy efficient deployment, clustering and routing in WSNs is proposed that focuses on the incorporation of autonomic functionalities in the existing approaches. The design of the protocol facilitates the design of innovative applications and services that are based on overlay topologies created through cooperation among the sensor nodes. PMID:22399931

  17. System and method for time synchronization in a wireless network

    SciTech Connect

    Gonia, Patrick S.; Kolavennu, Soumitri N.; Mahasenan, Arun V.; Budampati, Ramakrishna S.

    2010-03-30

    A system includes multiple wireless nodes forming a cluster in a wireless network, where each wireless node is configured to communicate and exchange data wirelessly based on a clock. One of the wireless nodes is configured to operate as a cluster master. Each of the other wireless nodes is configured to (i) receive time synchronization information from a parent node, (ii) adjust its clock based on the received time synchronization information, and (iii) broadcast time synchronization information based on the time synchronization information received by that wireless node. The time synchronization information received by each of the other wireless nodes is based on time synchronization information provided by the cluster master so that the other wireless nodes substantially synchronize their clocks with the clock of the cluster master.

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. Performance of Floor Acquisition Multiple Access in Ad-Hoc Networks

    DTIC Science & Technology

    1998-01-01

    collision avoidance dialogues (e.g., MACA, MACAW , and IEEE 802.11 DFWMAC) in the presence of hidden terminals. Simulations experiments are used to confirm...connected. Section IV compares by simulation the performance of FAMA-NCS with MACAW and DFWMAC. Our results show very clearly that carrier sensing at...strategies can be adopted (e.g., see those proposed for MACAW [1]). To simplify our analysis and description of FAMA-NCS, we do not address the effect of

  5. Mobility Based Key Management Technique for Multicast Security in Mobile Ad Hoc Networks

    PubMed Central

    Madhusudhanan, B.; Chitra, S.; Rajan, C.

    2015-01-01

    In MANET multicasting, forward and backward secrecy result in increased packet drop rate owing to mobility. Frequent rekeying causes large message overhead which increases energy consumption and end-to-end delay. Particularly, the prevailing group key management techniques cause frequent mobility and disconnections. So there is a need to design a multicast key management technique to overcome these problems. In this paper, we propose the mobility based key management technique for multicast security in MANET. Initially, the nodes are categorized according to their stability index which is estimated based on the link availability and mobility. A multicast tree is constructed such that for every weak node, there is a strong parent node. A session key-based encryption technique is utilized to transmit a multicast data. The rekeying process is performed periodically by the initiator node. The rekeying interval is fixed depending on the node category so that this technique greatly minimizes the rekeying overhead. By simulation results, we show that our proposed approach reduces the packet drop rate and improves the data confidentiality. PMID:25834838

  6. 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

  7. Beamspace Multiple Input Multiple Output. Part II: Steerable Antennas in Mobile Ad Hoc Networks

    DTIC Science & Technology

    2016-09-01

    reconfigurable antenna in- cluding the electronically steerable parasitic array radiator (ESPAR) promises a low form-factor steerable antenna with a single RF...MIMO that, in theory, approaches MIMO capacity using a single transceiver and an electronically steerable directional antenna. Standard MIMO transmits...Beamspace MIMO requires electronically steerable antennas. One such antenna is the Elec- tronically Steerable Parasitic Antenna Radiator (ESPAR). The initial

  8. High Throughput via Cross-Layer Interference Alignment for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2013-08-26

    minimized, e.g. all the signals are to be received within the cyclic prefix of orthogonal frequency division multiplexing ( OFDM ) system. For frequency...transmission [77]. In [77], the master continuously sends its OFDM -based training to the slaves via a dedicated synchronization channel, and the phase rotation...of OFDM subcarriers caused by time and frequency offset from the master is measured and compensated by the slaves before they send their own data

  9. MELOC - Memory and Location Optimized Caching for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2011-01-01

    locations PZID, CZID, <CD> list O/P: Cache Reallocation Operation Notations: PZ Previous Zone CZ Current Zone NCD List of nodes whose original...zone C Cache location crossing the zone CD[C] Cached data of C Trigger :( Cache Location moving from PZ to CZ) if (( NCD minus NPZ)> NCD /2) then...Insert CD[C] into H [PZ] Else No operation if (( NCD minus NCZ)> NCD /2) then No operation Else Delete CD[C] from C

  10. An Analysis Platform for Mobile Ad Hoc Network (MANET) Scenario Execution Log Data

    DTIC Science & Technology

    2016-01-01

    Case The SEDAP web interface has been tested with, and is compatible with, the following browsers: Internet Explorer, Google Chrome, and Iceweasel...a plugin-based platform that provides a flexible and efficient mechanism for the model generation process. This platform consists of a web portal...Fig. 8 SEDAP backend module diagram .......................................................18 Fig. 9 SEDAP web service diagram

  11. 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

  12. 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

  13. An Investigation into Component Reconfigurability Management for Dependable Ad-Hoc Networking

    DTIC Science & Technology

    2007-11-02

    Albrecht Schmidt, "Sensor-based Context-Awareness for Situated Computing", Workshop on Software Engineering and Pervasive Computing SEWPC00 at ICSE 2000...the 8th International Python Conference, Arlington, VA, USA. 24-27 January, 2000 [KindbergBarton2001] Tim Kindberg, John Barton, Jeff Morgan, Gene...Schmidt, Albrecht , Kofi Asante Aidoo, Antti Takaluoma, Urpo Tuomela, Kristof Van Laerhoven and Walter Van de Velde (1999). Advanced interaction in

  14. Medium Access Control in Ad Hoc Networks With Omni-Directional and Directional Antennas

    DTIC Science & Technology

    2004-06-01

    49 3.3.2 The DTOR Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 3.3.3 The MTOR Scheme...53 3.3 Calculation of various areas . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 3.4 The MTOR scheme...directional or directional reception can be applied to this approach. When the former is used, we call it MTOR scheme (short for “mixed-directional

  15. 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

  16. An Agent-based Model Simulation of Multiple Collaborating Mobile Ad Hoc Networks (MANET)

    DTIC Science & Technology

    2011-06-01

    RESULTS: Agent Learning Profiles Discounted Positive Reinforcement Learning Learning and Forgetting Forgetting is triggered by task conditions that...disable rational and deliberate mental models –forcing the agent to ignore (or forget) routine processes. Positive reinforcement is earned by an...deliberate behavior of agents as rational entities (model-based functions). 6.Experiment with positive reinforcement learning (with incremental gain over

  17. Mobility based key management technique for multicast security in mobile ad hoc networks.

    PubMed

    Madhusudhanan, B; Chitra, S; Rajan, C

    2015-01-01

    In MANET multicasting, forward and backward secrecy result in increased packet drop rate owing to mobility. Frequent rekeying causes large message overhead which increases energy consumption and end-to-end delay. Particularly, the prevailing group key management techniques cause frequent mobility and disconnections. So there is a need to design a multicast key management technique to overcome these problems. In this paper, we propose the mobility based key management technique for multicast security in MANET. Initially, the nodes are categorized according to their stability index which is estimated based on the link availability and mobility. A multicast tree is constructed such that for every weak node, there is a strong parent node. A session key-based encryption technique is utilized to transmit a multicast data. The rekeying process is performed periodically by the initiator node. The rekeying interval is fixed depending on the node category so that this technique greatly minimizes the rekeying overhead. By simulation results, we show that our proposed approach reduces the packet drop rate and improves the data confidentiality.

  18. 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

  19. In Reputation We Believe: Query Processing in Mobile Ad-Hoc Networks

    DTIC Science & Technology

    2005-01-01

    peers as: Definition 5 A device is a trusted peer for device if and only if $ &%(’ where ’ is ’s trust threshold. When a device receives a...not yet trusted devices. Consequently, the querying device cannot learn and adjust its trust degree about other peers in its vicinity it does not...out the discovery mes- sages more than once based on the responses it receives from its peers . 3.1.2. Information Advertisement When a cooperating

  20. 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.

  1. 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.

  2. 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

  3. Mechanisms for Prolonging Network Lifetime in Wireless Sensor Networks

    ERIC Educational Resources Information Center

    Yang, Yinying

    2010-01-01

    Sensors are used to monitor and control the physical environment. A Wireless Sensor Network (WSN) is composed of a large number of sensor nodes that are densely deployed either inside the phenomenon or very close to it [18][5]. Sensor nodes measure various parameters of the environment and transmit data collected to one or more sinks, using…

  4. 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.

  5. Graphical Model Theory for Wireless Sensor Networks

    SciTech Connect

    Davis, William B.

    2002-12-08

    Information processing in sensor networks, with many small processors, demands a theory of computation that allows the minimization of processing effort, and the distribution of this effort throughout the network. Graphical model theory provides a probabilistic theory of computation that explicitly addresses complexity and decentralization for optimizing network computation. The junction tree algorithm, for decentralized inference on graphical probability models, can be instantiated in a variety of applications useful for wireless sensor networks, including: sensor validation and fusion; data compression and channel coding; expert systems, with decentralized data structures, and efficient local queries; pattern classification, and machine learning. Graphical models for these applications are sketched, and a model of dynamic sensor validation and fusion is presented in more depth, to illustrate the junction tree algorithm.

  6. Theoretical Foundations of Wireless Networks

    DTIC Science & Technology

    2015-07-22

    ICASSP 2012 - 2012 IEEE International Conference on Acoustics, Speech and Signal Processing. 25- MAR-12, Kyoto , Japan. : , Yichuan Hu, A. Ribeiro...also worked in the development of optimal resource allocation protocols for random access networks in the presence of fading. These algorithms were...these distributions vary from link to link and are not known beforehand. Adaptive algorithms and protocols to learn fading’s probability distributions

  7. Design and Implementation of Secure Area Expansion Scheme for Public Wireless LAN Services

    NASA Astrophysics Data System (ADS)

    Watanabe, Ryu; Tanaka, Toshiaki

    Recently, wireless LAN (WLAN) technology has become a major wireless communication method. The communication bandwidth is increasing and speeds have attained rates exceeding 100 Mbps. Therefore, WLAN technology is regarded as one of the promising communication methods for future networks. In addition, public WLAN connection services can be used in many locations. However, the number of the access points (AP) is insufficient for seamless communication and it cannot be said that users can use the service ubiquitously. An ad-hoc network style connection can be used to expand the coverage area of a public WLAN service. By relaying the user messages among the user nodes, a node can obtain an Internet connection via an AP, even though the node is located outside the AP's direct wireless connection area. Such a coverage area extending technology has many advantages thanks to the feature that no additional infrastructure is required. Therefore, there is a strong demand for this technology as it allows the cost-effective construction of future networks. When a secure ad-hoc routing protocol is used for message exchange in the WLAN service, the message routes are protected from malicious behavior such as route forging and can be maintained appropriately. To do this, however, a new node that wants to join the WLAN service has to obtain information such as the public key certificate and IP address in order to start secure ad-hoc routing. In other words, an initial setup is required for every network node to join the WLAN service properly. Ordinarily, such information should be assigned from the AP. However, new nodes cannot always contact an AP directly. Therefore, there are problems about information delivery in the initial setup of a network node. These problems originate in the multi hop connection based on the ad-hoc routing protocols. In order to realize an expanded area WLAN service, in this paper, the authors propose a secure public key certificate and address provision

  8. New Applications for the Testing and Visualization of Wireless Networks

    NASA Technical Reports Server (NTRS)

    Griffin, Robert I.; Cauley, Michael A.; Pleva, Michael A.; Seibert, Marc A.; Lopez, Isaac

    2005-01-01

    Traditional techniques for examining wireless networks use physical link characteristics such as Signal-to-Noise (SNR) ratios to assess the performance of wireless networks. Such measurements may not be reliable indicators of available bandwidth. This work describes two new software applications developed at NASA Glenn Research Center for the investigation of wireless networks. GPSIPerf combines measurements of Transmission Control Protocol (TCP) throughput with Global Positioning System (GPS) coordinates to give users a map of wireless bandwidth for outdoor environments where a wireless infrastructure has been deployed. GPSIPerfView combines the data provided by GPSIPerf with high-resolution digital elevation maps (DEM) to help users visualize and assess the impact of elevation features on wireless networks in a given sample area. These applications were used to examine TCP throughput in several wireless network configurations at desert field sites near Hanksville, Utah during May of 2004. Use of GPSIPerf and GPSIPerfView provides a geographically referenced picture of the extent and deterioration of TCP throughput in tested wireless network configurations. GPSIPerf results from field-testing in Utah suggest that it can be useful in assessing other wireless network architectures, and may be useful to future human-robotic exploration missions.

  9. Diagnosing degradation of services in hybrid wireless tactical networks

    NASA Astrophysics Data System (ADS)

    Tati, Srikar; Novotny, Petr; Ko, Bong Jun; Wolf, Alexander; Swami, Ananthram; La Porta, Thomas

    2013-05-01

    In this paper, we consider a problem related to service management and deployment in tactical military networks. Tactical networks are typically hybrid wireless networks in which there are both static and mobile nodes with several wireless interfaces, such as 802.11, 3G, satellite, etc. In tactical networks, performance degradation in services could prove fatal, so it must be diagnosed quickly. This degradation could be due to mobility or bottlenecks in capacity at network layer. We provide a cross-layer framework to detect and diagnose these causes of performance degradation as part of service management; it includes a monitoring model of services and a network model for hybrid wireless networks. In addition, we give a working example in tactical military networks to illustrate our framework. We provide an experimental setup to simulate our hybrid wireless tactical network scenario along with preliminary results.

  10. Secure dissemination of electronic healthcare records in distributed wireless environments.

    PubMed

    Belsis, Petros; Vassis, Dimitris; Skourlas, Christos; Pantziou, Grammati

    2008-01-01

    A new networking paradigm has emerged with the appearance of wireless computing. Among else ad-hoc networks, mobile and ubiquitous environments can boost the performance of systems in which they get applied. Among else, medical environments are a convenient example of their applicability. With the utilisation of wireless infrastructures, medical data may be accessible to healthcare practitioners, enabling continuous access to medical data. Due to the critical nature of medical information, the design and implementation of these infrastructures demands special treatment in order to meet specific requirements; among else, special care should be taken in order to manage interoperability, security, and in order to deal with bandwidth and hardware resource constraints that characterize the wireless topology. In this paper we present an architecture that attempts to deal with these issues; moreover, in order to prove the validity of our approach we have also evaluated the performance of our platform through simulation in different operating scenarios.

  11. Fiber Optic Infrastructure for Wireless Communication Networks

    NASA Astrophysics Data System (ADS)

    Lau, Kam Y.; Cutrer, David M.; Georges, John B.; Yeung, Simon

    It is clear that to meet the new demands of wireless customers, conventional cellular service providers and upcoming Personal Communication Service (PCS) providers for conventional phone service and high bandwidth wireless LAN must upgrade their networks to provide complete radio coverage. This evolution has motivated the need for low-cost systems that transport radio signals to and from areas of poor signal coverage. The most important area where this problem must be solved is inside of buildings, since this is where people spend most of their time. Unfortunately, the in-building environment is also the most challenging area to provide radio coverage due to severe attenuation and multi-path effects. The problem must be tackled from the viewpoint of optimization of performance/cost ratio of the network. In this paper, we describe a system-level approach to tackle this problem. We demonstrate how one can trade-off hardware performance, which represent cost, with proper choice of system architecture which includes, among other factors, in-building radio environment, to arrive at an optimum network solution technically and economically.

  12. Mobile middleware for wireless body area network.

    PubMed

    Chen, Xiang; Waluyo, Agustinus Borgy; Pek, Isaac; Yeoh, Wee-Soon

    2010-01-01

    This paper presents a flexible, efficient and lightweight Wireless Body Area Network (WBAN) Middleware. The Middleware is developed to bridge the communication between mobile device as a gateway and the sensor nodes, and therefore it shields the underlying sensor and OS/protocol stack away from the WBAN application layer. The middleware is coded in the form of lightweight dynamic link library, which allows the application developer to simply incorporate the middleware resource dynamic link library into their application and call the required functions (i.e. data acquisition, resource management and configurations). A showcase of the middleware deployment is exhibited at the end of the paper.

  13. Wireless sensor network for irrigation application in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless sensor network was deployed in a cotton field to monitor soil water status for irrigation. The network included two systems, a Decagon system and a microcontroller-based system. The Decagon system consists of soil volumetric water-content sensors, wireless data loggers, and a central data...

  14. Utilising eduroam[TM] Architecture in Building Wireless Community Networks

    ERIC Educational Resources Information Center

    Huhtanen, Karri; Vatiainen, Heikki; Keski-Kasari, Sami; Harju, Jarmo

    2008-01-01

    Purpose: eduroam[TM] has already been proved to be a scalable, secure and feasible way for universities and research institutions to connect their wireless networks into a WLAN roaming community, but the advantages of eduroam[TM] have not yet been fully discovered in the wireless community networks aimed at regular consumers. This aim of this…

  15. 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

  16. Self Calibrated Wireless Distributed Environmental Sensory Networks

    PubMed Central

    Fishbain, Barak; Moreno-Centeno, Erick

    2016-01-01

    Recent advances in sensory and communication technologies have made Wireless Distributed Environmental Sensory Networks (WDESN) technically and economically feasible. WDESNs present an unprecedented tool for studying many environmental processes in a new way. However, the WDESNs’ calibration process is a major obstacle in them becoming the common practice. Here, we present a new, robust and efficient method for aggregating measurements acquired by an uncalibrated WDESN, and producing accurate estimates of the observed environmental variable’s true levels rendering the network as self-calibrated. The suggested method presents novelty both in group-decision-making and in environmental sensing as it offers a most valuable tool for distributed environmental monitoring data aggregation. Applying the method on an extensive real-life air-pollution dataset showed markedly more accurate results than the common practice and the state-of-the-art. PMID:27098279

  17. Self Calibrated Wireless Distributed Environmental Sensory Networks.

    PubMed

    Fishbain, Barak; Moreno-Centeno, Erick

    2016-04-21

    Recent advances in sensory and communication technologies have made Wireless Distributed Environmental Sensory Networks (WDESN) technically and economically feasible. WDESNs present an unprecedented tool for studying many environmental processes in a new way. However, the WDESNs' calibration process is a major obstacle in them becoming the common practice. Here, we present a new, robust and efficient method for aggregating measurements acquired by an uncalibrated WDESN, and producing accurate estimates of the observed environmental variable's true levels rendering the network as self-calibrated. The suggested method presents novelty both in group-decision-making and in environmental sensing as it offers a most valuable tool for distributed environmental monitoring data aggregation. Applying the method on an extensive real-life air-pollution dataset showed markedly more accurate results than the common practice and the state-of-the-art.

  18. Validation of a wireless accelerometer network for energy expenditure measurement.

    PubMed

    Montoye, Alexander H K; Dong, Bo; Biswas, Subir; Pfeiffer, Karin A

    2016-11-01

    The purpose of this study was to validate a wireless network of accelerometers and compare it to a hip-mounted accelerometer for predicting energy expenditure in a semi-structured environment. Adults (n = 25) aged 18-30 engaged in 14 sedentary, ambulatory, exercise, and lifestyle activities over a 60-min protocol while wearing a portable metabolic analyser, hip-mounted accelerometer, and wireless network of three accelerometers worn on the right wrist, thigh, and ankle. Participants chose the order and duration of activities. Artificial neural networks were created separately for the wireless network and hip accelerometer for energy expenditure prediction. The wireless network had higher correlations (r = 0.79 vs. r = 0.72, P < 0.01) but similar root mean square error (2.16 vs. 2.09 METs, P > 0.05) to the hip accelerometer. Measured (from metabolic analyser) and predicted energy expenditure from the hip accelerometer were significantly different for the 3 of the 14 activities (lying down, sweeping, and cycle fast); conversely, measured and predicted energy expenditure from the wireless network were not significantly different for any activity. In conclusion, the wireless network yielded a small improvement over the hip accelerometer, providing evidence that the wireless network can produce accurate estimates of energy expenditure in adults participating in a range of activities.

  19. 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

  20. Multipath Routing in Wireless Sensor Networks: Survey and Research Challenges

    PubMed Central

    Radi, Marjan; Dezfouli, Behnam; Bakar, Kamalrulnizam Abu; Lee, Malrey

    2012-01-01

    A wireless sensor network is a large collection of sensor nodes with limited power supply and constrained computational capability. Due to the restricted communication range and high density of sensor nodes, packet forwarding in sensor networks is usually performed through multi-hop data transmission. Therefore, routing in wireless sensor networks has been considered an important field of research over the past decade. Nowadays, multipath routing approach is widely used in wireless sensor networks to improve network performance through efficient utilization of available network resources. Accordingly, the main aim of this survey is to present the concept of the multipath routing approach and its fundamental challenges, as well as the basic motivations for utilizing this technique in wireless sensor networks. In addition, we present a comprehensive taxonomy on the existing multipath routing protocols, which are especially designed for wireless sensor networks. We highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages. Furthermore, this paper compares and summarizes the state-of-the-art multipath routing techniques from the network application point of view. Finally, we identify open issues for further research in the development of multipath routing protocols for wireless sensor networks. PMID:22368490

  1. Multipath routing in wireless sensor networks: survey and research challenges.

    PubMed

    Radi, Marjan; Dezfouli, Behnam; Abu Bakar, Kamalrulnizam; Lee, Malrey

    2012-01-01

    A wireless sensor network is a large collection of sensor nodes with limited power supply and constrained computational capability. Due to the restricted communication range and high density of sensor nodes, packet forwarding in sensor networks is usually performed through multi-hop data transmission. Therefore, routing in wireless sensor networks has been considered an important field of research over the past decade. Nowadays, multipath routing approach is widely used in wireless sensor networks to improve network performance through efficient utilization of available network resources. Accordingly, the main aim of this survey is to present the concept of the multipath routing approach and its fundamental challenges, as well as the basic motivations for utilizing this technique in wireless sensor networks. In addition, we present a comprehensive taxonomy on the existing multipath routing protocols, which are especially designed for wireless sensor networks. We highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages. Furthermore, this paper compares and summarizes the state-of-the-art multipath routing techniques from the network application point of view. Finally, we identify open issues for further research in the development of multipath routing protocols for wireless sensor networks.

  2. A Novel Energy-Driven Architecture for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Jayakody, D. N. K.; Khan, Z. A.; Rodrigo; de Lamare, C.; Thompson, J.

    2017-01-01

    This paper proposes a novel Energy-Driven Architecture (EDA) as a durable architecture and considers almost all principal energy constituents of wireless sensor networks applications. By creating a single overall model, a tolerable formulation is then offered to communicate the total energy use of a wireless sensor network application regarding the energy constituents. The formulation provides a tangible illustration for analyzing the performance of a wireless sensor network application, optimizing its constituent’s operations, as well as creating more energy saving applications. The simulations are employed to show the feasibility of our model and also energy formulation.

  3. Autonomous vision networking: miniature wireless sensor networks with imaging technology

    NASA Astrophysics Data System (ADS)

    Messinger, Gioia; Goldberg, Giora

    2006-09-01

    The recent emergence of integrated PicoRadio technology, the rise of low power, low cost, System-On-Chip (SOC) CMOS imagers, coupled with the fast evolution of networking protocols and digital signal processing (DSP), created a unique opportunity to achieve the goal of deploying large-scale, low cost, intelligent, ultra-low power distributed wireless sensor networks for the visualization of the environment. Of all sensors, vision is the most desired, but its applications in distributed sensor networks have been elusive so far. Not any more. The practicality and viability of ultra-low power vision networking has been proven and its applications are countless, from security, and chemical analysis to industrial monitoring, asset tracking and visual recognition, vision networking represents a truly disruptive technology applicable to many industries. The presentation discusses some of the critical components and technologies necessary to make these networks and products affordable and ubiquitous - specifically PicoRadios, CMOS imagers, imaging DSP, networking and overall wireless sensor network (WSN) system concepts. The paradigm shift, from large, centralized and expensive sensor platforms, to small, low cost, distributed, sensor networks, is possible due to the emergence and convergence of a few innovative technologies. Avaak has developed a vision network that is aided by other sensors such as motion, acoustic and magnetic, and plans to deploy it for use in military and commercial applications. In comparison to other sensors, imagers produce large data files that require pre-processing and a certain level of compression before these are transmitted to a network server, in order to minimize the load on the network. Some of the most innovative chemical detectors currently in development are based on sensors that change color or pattern in the presence of the desired analytes. These changes are easily recorded and analyzed by a CMOS imager and an on-board DSP processor

  4. Impact of reduced scale free network on wireless sensor network

    NASA Astrophysics Data System (ADS)

    Keshri, Neha; Gupta, Anurag; Mishra, Bimal Kumar

    2016-12-01

    In heterogeneous wireless sensor network (WSN) each data-packet traverses through multiple hops over restricted communication range before it reaches the sink. The amount of energy required to transmit a data-packet is directly proportional to the number of hops. To balance the energy costs across the entire network and to enhance the robustness in order to improve the lifetime of WSN becomes a key issue of researchers. Due to high dimensionality of an epidemic model of WSN over a general scale free network, it is quite difficult to have close study of network dynamics. To overcome this complexity, we simplify a general scale free network by partitioning all of its motes into two classes: higher-degree motes and lower-degree motes, and equating the degrees of all higher-degree motes with lower-degree motes, yielding a reduced scale free network. We develop an epidemic model of WSN based on reduced scale free network. The existence of unique positive equilibrium is determined with some restrictions. Stability of the system is proved. Furthermore, simulation results show improvements made in this paper have made the entire network have a better robustness to the network failure and the balanced energy costs. This reduced model based on scale free network theory proves more applicable to the research of WSN.

  5. Software-defined Radio Based Measurement Platform for Wireless Networks

    PubMed Central

    Chao, I-Chun; Lee, Kang B.; Candell, Richard; Proctor, Frederick; Shen, Chien-Chung; Lin, Shinn-Yan

    2015-01-01

    End-to-end latency is critical to many distributed applications and services that are based on computer networks. There has been a dramatic push to adopt wireless networking technologies and protocols (such as WiFi, ZigBee, WirelessHART, Bluetooth, ISA100.11a, etc.) into time-critical applications. Examples of such applications include industrial automation, telecommunications, power utility, and financial services. While performance measurement of wired networks has been extensively studied, measuring and quantifying the performance of wireless networks face new challenges and demand different approaches and techniques. In this paper, we describe the design of a measurement platform based on the technologies of software-defined radio (SDR) and IEEE 1588 Precision Time Protocol (PTP) for evaluating the performance of wireless networks. PMID:27891210

  6. Software-defined Radio Based Measurement Platform for Wireless Networks.

    PubMed

    Chao, I-Chun; Lee, Kang B; Candell, Richard; Proctor, Frederick; Shen, Chien-Chung; Lin, Shinn-Yan

    2015-10-01

    End-to-end latency is critical to many distributed applications and services that are based on computer networks. There has been a dramatic push to adopt wireless networking technologies and protocols (such as WiFi, ZigBee, WirelessHART, Bluetooth, ISA100.11a, etc.) into time-critical applications. Examples of such applications include industrial automation, telecommunications, power utility, and financial services. While performance measurement of wired networks has been extensively studied, measuring and quantifying the performance of wireless networks face new challenges and demand different approaches and techniques. In this paper, we describe the design of a measurement platform based on the technologies of software-defined radio (SDR) and IEEE 1588 Precision Time Protocol (PTP) for evaluating the performance of wireless networks.

  7. Wireless networking and its application in nuclear safeguards.

    SciTech Connect

    Goncalves, Joao G. M.; Smartt, Heidi Anne; Conti, Michele; Caskey, Susan Adele; Rossini, Angelo; Glidewell, Donnie Dwight

    2004-07-01

    Wireless networking can provide a cost effective and convenient method for installing and operating an unattended or remote monitoring system in an established facility. There is concern, however, that wireless devices can interfere with each other and with other radio systems within the facility. Additionally, there is concern that these devices add a potential risk to the security of the network. Since all data is transmitted in the air, it is possible for an unauthorized user to intercept the data transmissions and/or insert data onto the network if proper security is not in place. This paper describes a study being undertaken to highlight the benefits of wireless networking, evaluate interference and methods for mitigation, recommend security architectures, and present the results of a wireless network demonstration between Sandia National Laboratories (SNL) and the Joint Research Centre (JRC).

  8. Differential Space-Time Modulation for Wideband Wireless Networks

    DTIC Science & Technology

    2006-09-30

    modulation for wireless relay networks in Nakagami -m channels,” in Proceedings of the 2006 IEEE International Conference on Acoustic, Speech, and Signal... Nakagami -m fading channels," in Proceedings of the 6th IEEE International Workshop on Signal Processing Advances for Wireless Communications (SPAWC

  9. Are Wireless Networks the Wave of the Future?

    ERIC Educational Resources Information Center

    Young, Jeffrey R.

    1999-01-01

    Some college administrators feel the next major trend in educational technology will be wireless networks that let students and professors connect to the Internet with radio waves rather than cumbersome cables. Several universities are already using the less expensive technology. However, some find the slower speed of available wireless services…

  10. A Wireless Sensor Network For Soil Monitoring

    NASA Astrophysics Data System (ADS)

    Szlavecz, K.; Cogan, J.; Musaloiu-Elefteri, R.; Small, S.; Terzis, A.; Szalay, A.

    2005-12-01

    The most spatially complex stratum of a terrestrial ecosystem is its soil. Among the major challenges of studying the soil ecosystem are the diversity and the cryptic nature of biota, and the enormous heterogeneity of the soil substrate. Often this patchiness drives spatial distribution of soil organisms, yet our knowledge on the spatio-temporal patterns of soil conditions is limited. To monitor the environmental conditions at biologically meaningful spatial scales we have developed and deployed a wireless sensor network of thirty nodes. Each node is based on a MICAz mote connected to a custom-built sensor suite that includes a Watermark soil moisture sensor, an Irrometer soil temperature sensor, and sensors capable of recording ambient temperature and light intensity. To assess CO2 production at the ground level a subset of the nodes is equipped with Telaire 6004 CO2 sensor. We developed the software running on the motes from scratch, using the TinyOS development environment. Each mote collects measurements every minute, and stores them persistently in a non-volatile memory. The decision to store data locally at each node enables us to reliably retrieve the data in the face of network losses and premature node failures due to power depletion. Collected measurements are retrieved over the wireless network through a PC-class computer acting as a gateway between the sensor network and the Internet. Considering that motes are battery powered, the largest obstacle hindering long-term sensor network deployments is power consumption. To address this problem, our software powers down sensors between sampling cycles and turns off the radio (the most energy prohibitive mote component) when not in use. By doing so we were able to increase node lifetime by a factor of ten. We collected field data over several weeks. The data was ingested into a SQL Server database, which provides data access through a .NET web services interface. The database provides functions for spatial

  11. Visualization and Analysis of Wireless Sensor Network Data for Smart Civil Structure Applications Based On Spatial Correlation Technique

    NASA Astrophysics Data System (ADS)

    Chowdhry, Bhawani Shankar; White, Neil M.; Jeswani, Jai Kumar; Dayo, Khalil; Rathi, Manorma

    2009-07-01

    Disasters affecting infrastructure, such as the 2001 earthquakes in India, 2005 in Pakistan, 2008 in China and the 2004 tsunami in Asia, provide a common need for intelligent buildings and smart civil structures. Now, imagine massive reductions in time to get the infrastructure working again, realtime information on damage to buildings, massive reductions in cost and time to certify that structures are undamaged and can still be operated, reductions in the number of structures to be rebuilt (if they are known not to be damaged). Achieving these ideas would lead to huge, quantifiable, long-term savings to government and industry. Wireless sensor networks (WSNs) can be deployed in buildings to make any civil structure both smart and intelligent. WSNs have recently gained much attention in both public and research communities because they are expected to bring a new paradigm to the interaction between humans, environment, and machines. This paper presents the deployment of WSN nodes in the Top Quality Centralized Instrumentation Centre (TQCIC). We created an ad hoc networking application to collect real-time data sensed from the nodes that were randomly distributed throughout the building. If the sensors are relocated, then the application automatically reconfigures itself in the light of the new routing topology. WSNs are event-based systems that rely on the collective effort of several micro-sensor nodes, which are continuously observing a physical phenomenon. WSN applications require spatially dense sensor deployment in order to achieve satisfactory coverage. The degree of spatial correlation increases with the decreasing inter-node separation. Energy consumption is reduced dramatically by having only those sensor nodes with unique readings transmit their data. We report on an algorithm based on a spatial correlation technique that assures high QoS (in terms of SNR) of the network as well as proper utilization of energy, by suppressing redundant data transmission

  12. Wireless Sensor Networks for Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Liang, X.; Liang, Y.; Navarro, M.; Zhong, X.; Villalba, G.; Li, Y.; Davis, T.; Erratt, N.

    2015-12-01

    Wireless sensor networks (WSNs) have gained an increasing interest in a broad range of new scientific research and applications. WSN technologies can provide high resolution for spatial and temporal data which has not been possible before, opening up new opportunities. On the other hand, WSNs, particularly outdoor WSNs in harsh environments, present great challenges for scientists and engineers in terms of the network design, deployment, operation, management, and maintenance. Since 2010, we have been working on the deployment of an outdoor multi-hop WSN testbed for hydrological/environmental monitoring in a forested hill-sloped region at the Audubon Society of Western Pennsylvania (ASWP), Pennsylvania, USA. The ASWP WSN testbed has continuously evolved and had more than 80 nodes by now. To our knowledge, the ASWP WSN testbed represents one of the first known long-term multi-hop WSN deployments in an outdoor environment. As simulation and laboratory methods are unable to capture the complexity of outdoor environments (e.g., forests, oceans, mountains, or glaciers), which significantly affect WSN operations and maintenance, experimental deployments are essential to investigate and understand WSN behaviors and performances as well as its maintenance characteristics under these harsh conditions. In this talk, based on our empirical studies with the ASWP WSN testbed, we will present our discoveries and investigations on several important aspects including WSN energy profile, node reprogramming, network management system, and testbed maintenance. We will then provide our insight into these critical aspects of outdoor WSN deployments and operations.

  13. Optimizing Retransmission Threshold in Wireless Sensor Networks

    PubMed Central

    Bi, Ran; Li, Yingshu; Tan, Guozhen; Sun, Liang

    2016-01-01

    The retransmission threshold in wireless sensor networks is critical to the latency of data delivery in the networks. However, existing works on data transmission in sensor networks did not consider the optimization of the retransmission threshold, and they simply set the same retransmission threshold for all sensor nodes in advance. The method did not take link quality and delay requirement into account, which decreases the probability of a packet passing its delivery path within a given deadline. This paper investigates the problem of finding optimal retransmission thresholds for relay nodes along a delivery path in a sensor network. The object of optimizing retransmission thresholds is to maximize the summation of the probability of the packet being successfully delivered to the next relay node or destination node in time. A dynamic programming-based distributed algorithm for finding optimal retransmission thresholds for relay nodes along a delivery path in the sensor network is proposed. The time complexity is OnΔ·max1≤i≤n{ui}, where ui is the given upper bound of the retransmission threshold of sensor node i in a given delivery path, n is the length of the delivery path and Δ is the given upper bound of the transmission delay of the delivery path. If Δ is greater than the polynomial, to reduce the time complexity, a linear programming-based (1+pmin)-approximation algorithm is proposed. Furthermore, when the ranges of the upper and lower bounds of retransmission thresholds are big enough, a Lagrange multiplier-based distributed O(1)-approximation algorithm with time complexity O(1) is proposed. Experimental results show that the proposed algorithms have better performance. PMID:27171092

  14. Optimizing Retransmission Threshold in Wireless Sensor Networks.

    PubMed

    Bi, Ran; Li, Yingshu; Tan, Guozhen; Sun, Liang

    2016-05-10

    The retransmission threshold in wireless sensor networks is critical to the latency of data delivery in the networks. However, existing works on data transmission in sensor networks did not consider the optimization of the retransmission threshold, and they simply set the same retransmission threshold for all sensor nodes in advance. The method did not take link quality and delay requirement into account, which decreases the probability of a packet passing its delivery path within a given deadline. This paper investigates the problem of finding optimal retransmission thresholds for relay nodes along a delivery path in a sensor network. The object of optimizing retransmission thresholds is to maximize the summation of the probability of the packet being successfully delivered to the next relay node or destination node in time. A dynamic programming-based distributed algorithm for finding optimal retransmission thresholds for relay nodes along a delivery path in the sensor network is proposed. The time complexity is O n Δ · max 1 ≤ i ≤ n { u i } , where u i is the given upper bound of the retransmission threshold of sensor node i in a given delivery path, n is the length of the delivery path and Δ is the given upper bound of the transmission delay of the delivery path. If Δ is greater than the polynomial, to reduce the time complexity, a linear programming-based ( 1 + p m i n ) -approximation algorithm is proposed. Furthermore, when the ranges of the upper and lower bounds of retransmission thresholds are big enough, a Lagrange multiplier-based distributed O ( 1 ) -approximation algorithm with time complexity O ( 1 ) is proposed. Experimental results show that the proposed algorithms have better performance.

  15. Mobility management techniques for the next-generation wireless networks

    NASA Astrophysics Data System (ADS)

    Sun, Junzhao; Howie, Douglas P.; Sauvola, Jaakko J.

    2001-10-01

    The tremendous demands from social market are pushing the booming development of mobile communications faster than ever before, leading to plenty of new advanced techniques emerging. With the converging of mobile and wireless communications with Internet services, the boundary between mobile personal telecommunications and wireless computer networks is disappearing. Wireless networks of the next generation need the support of all the advances on new architectures, standards, and protocols. Mobility management is an important issue in the area of mobile communications, which can be best solved at the network layer. One of the key features of the next generation wireless networks is all-IP infrastructure. This paper discusses the mobility management schemes for the next generation mobile networks through extending IP's functions with mobility support. A global hierarchical framework model for the mobility management of wireless networks is presented, in which the mobility management is divided into two complementary tasks: macro mobility and micro mobility. As the macro mobility solution, a basic principle of Mobile IP is introduced, together with the optimal schemes and the advances in IPv6. The disadvantages of the Mobile IP on solving the micro mobility problem are analyzed, on the basis of which three main proposals are discussed as the micro mobility solutions for mobile communications, including Hierarchical Mobile IP (HMIP), Cellular IP, and Handoff-Aware Wireless Access Internet Infrastructure (HAWAII). A unified model is also described in which the different micro mobility solutions can coexist simultaneously in mobile networks.

  16. High Fidelity Simulations of Large-Scale Wireless Networks

    SciTech Connect

    Onunkwo, Uzoma; Benz, Zachary

    2015-11-01

    The worldwide proliferation of wireless connected devices continues to accelerate. There are 10s of billions of wireless links across the planet with an additional explosion of new wireless usage anticipated as the Internet of Things develops. Wireless technologies do not only provide convenience for mobile applications, but are also extremely cost-effective to deploy. Thus, this trend towards wireless connectivity will only continue and Sandia must develop the necessary simulation technology to proactively analyze the associated emerging vulnerabilities. Wireless networks are marked by mobility and proximity-based connectivity. The de facto standard for exploratory studies of wireless networks is discrete event simulations (DES). However, the simulation of large-scale wireless networks is extremely difficult due to prohibitively large turnaround time. A path forward is to expedite simulations with parallel discrete event simulation (PDES) techniques. The mobility and distance-based connectivity associated with wireless simulations, however, typically doom PDES and fail to scale (e.g., OPNET and ns-3 simulators). We propose a PDES-based tool aimed at reducing the communication overhead between processors. The proposed solution will use light-weight processes to dynamically distribute computation workload while mitigating communication overhead associated with synchronizations. This work is vital to the analytics and validation capabilities of simulation and emulation at Sandia. We have years of experience in Sandia’s simulation and emulation projects (e.g., MINIMEGA and FIREWHEEL). Sandia’s current highly-regarded capabilities in large-scale emulations have focused on wired networks, where two assumptions prevent scalable wireless studies: (a) the connections between objects are mostly static and (b) the nodes have fixed locations.

  17. Fast notification architecture for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Hahk

    2013-03-01

    In an emergency, since it is vital to transmit the message to the users immediately after analysing the data to prevent disaster, this article presents the deployment of a fast notification architecture for a wireless sensor network. The sensor nodes of the proposed architecture can monitor an emergency situation periodically and transmit the sensing data, immediately to the sink node. We decide on the grade of fire situation according to the decision rule using the sensing values of temperature, CO, smoke density and temperature increasing rate. On the other hand, to estimate the grade of air pollution, the sensing data, such as dust, formaldehyde, NO2, CO2, is applied to the given knowledge model. Since the sink node in the architecture has a ZigBee interface, it can transmit the alert messages in real time according to analysed results received from the host server to the terminals equipped with a SIM card-type ZigBee module. Also, the host server notifies the situation to the registered users who have cellular phone through short message service server of the cellular network. Thus, the proposed architecture can adapt an emergency situation dynamically compared to the conventional architecture using video processing. In the testbed, after generating air pollution and fire data, the terminal receives the message in less than 3 s. In the test results, this system can also be applied to buildings and public areas where many people gather together, to prevent unexpected disasters in urban settings.

  18. Scaleable wireless web-enabled sensor networks

    NASA Astrophysics Data System (ADS)

    Townsend, Christopher P.; Hamel, Michael J.; Sonntag, Peter A.; Trutor, B.; Arms, Steven W.

    2002-06-01

    Our goal was to develop a long life, low cost, scalable wireless sensing network, which collects and distributes data from a wide variety of sensors over the internet. Time division multiple access was employed with RF transmitter nodes (each w/unique16 bit address) to communicate digital data to a single receiver (range 1/3 mile). One thousand five channel nodes can communicate to one receiver (30 minute update). Current draw (sleep) is 20 microamps, allowing 5 year battery life w/one 3.6 volt Li-Ion AA size battery. The network nodes include sensor excitation (AC or DC), multiplexer, instrumentation amplifier, 16 bit A/D converter, microprocessor, and RF link. They are compatible with thermocouples, strain gauges, load/torque transducers, inductive/capacitive sensors. The receiver (418 MHz) includes a single board computer (SBC) with Ethernet capability, internet file transfer protocols (XML/HTML), and data storage. The receiver detects data from specific nodes, performs error checking, records the data. The web server interrogates the SBC (from Microsoft's Internet Explorer or Netscape's Navigator) to distribute data. This system can collect data from thousands of remote sensors on a smart structure, and be shared by an unlimited number of users.

  19. Challenges for Environmental Wireless Sensor Networks (WSNs) (Invited)

    NASA Astrophysics Data System (ADS)

    Liang, X.; Davis, T. W.

    2013-12-01

    There are many challenges posed to researchers looking to collect eco-hydrological information with monitoring systems exposed to the natural environment due, in part, to the unpredictable interactions between the environment and the wireless hardware and the scale of the deployment. While wireless sensor network technology has introduced autonomy and pervasiveness to studying the environment, it is not a panacea for outdoor monitoring systems. Despite the fact that each outdoor deployment will encounter its own unique set of challenges, it is often a benefit to researchers to know what problems were faced during other deployments and how these problems were mitigated or solved. This work examines a long-term (i.e., multi-year) environmental wireless sensor network which was deployed in a forested hill-sloped region of western Pennsylvania, USA and the main challenges that were encountered. These include: (1) the startup and maintenance costs of the wireless network; (2) the data collection system and remote access to the network; (3) the security of the network hardware and software; and (4) the reliability of wireless network connectivity. Based on our field study, it was found that while wireless sensor networks (WSNs) have less expensive startup costs compared to similarly sized wired systems (such as data logging), the WSN has relatively high maintenance costs as it requires frequent site visits (mean of 38 days per wireless node). One possible way to reduce the maintenance costs is by adjusting the sampling and/or collection frequency of the wireless nodes. In addition to the high maintenance costs, wireless communications, especially over complex networks, have low success rates of data capture from the field (approximately 50%). Environmental conditions, such as background noise, interference and weather conditions, may significantly influence the wireless communications. Technological advancements (such as smart sampling and data compression) are being

  20. 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.