Dissertations / Theses on the topic '080503 Networking and Communications'
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1
Walton, Michael Tanner. "Mesh Networking for Inter-UAV Communications." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1505208/.
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Unmanned aerial systems (UASs) have a great potential to enhanced situational awareness in public safety operations. Many UASs operating in the same airspace can cause mid-air collisions. NASA and the FAA are developing a UAS traffic management (UTM) system, which could be used in public safety operations to manage the UAS airspace. UTM relies on an existing communication backhaul, however natural disasters may disrupt existing communications infrastructure or occur in areas where no backhaul exists. This thesis outlines a robust communications alternative that interfaces a fleet of UASs with a UTM service supplier (USS) over a mesh network. Additionally, this thesis outlines an algorithm for vehicle-to-vehicle discovery and communication over the mesh network.
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Aydeger, Abdullah. "Software Defined Networking for Smart Grid Communications." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2580.
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Emerging Software Defined Networking (SDN) technology has provided excellent flexibility to large-scale networks in terms of control, management, security, and maintenance. On the other hand, recent years witnessed a tremendous growth of the critical infrastructure networks, namely the Smart-Grid, in terms of its underlying communication infrastructure. Such large local networks requires significant effort in terms of network management and security. We explore the potential utilization of the SDN technology over the Smart Grid communication architecture. Specifically, we introduce three novel SDN deployment scenarios in local networks of Smart Grid. Moreover, we also investigate the pertinent security aspects with each deployment scenario along with possible solutions. On the other hand, we conducted experiments by using actual Smart Grid communication data to assess the recovery performance of the proposed SDN-based system. The results show that SDN is a viable technology for the Smart Grid communications with almost negligible delays in switching to backup wireless links.
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Sadek, Ahmed Kamel. "Cross-layer design for cooperative communications and networking." College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/6735.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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El, Sherif Amr. "Cognitive multiple access for cooperative communications and networking." College Park, Md.: University of Maryland, 2009. http://hdl.handle.net/1903/9601.
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Thesis (Ph.D.) -- University of Maryland, College Park, 2009.Thesis research directed by: Dept. of Electrical and Computer Engineering . Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Zyambo, Emmanuel Baleke. "High-speed wireless infrared communications." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275377.
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Bernard, Jon Ashley. "Communications Resource Allocation: Feasibility Assessment for Tactial Networking Applications." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/31649.
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The research reported here offers a solution to the communications resource allocation problem. Unlike earlier approaches to this problem, we employ a time-sliced event model where messages are sent and received in a single time slice called an epoch. In addition, we also consider networks that contain relay nodes capable of only transferring messages. Consequently, network topologies can be considered where a given node is not directly connected to every other node and must use one or more relay nodes in order to get a message to some destination. The resulting architectures broaden the networks to be considered and enable the capability of constructing more realistic communication scenarios.
In this paper we modify the standard MCNF model by turning our focus to feasibility instead of optimality in an effort to provide adequate and accurate decision support to communication network planners. Given a network configuration and message requirements, our goal is to determine if the proposed scenario is feasible in terms of the communication resources available.
To meet this goal, three algorithms are presented that each solve the extended MCNF problem with varying degrees of accuracy and run-time requirements.
Experimental results show that a large number of multi-variable interactions among input parameters play a key role in determining feasibility and predicting expected execution time. Several heuristics are presented that reduce run-time dramatically, in some cases by a factor of 37.
Each algorithm is tested on a range of inputs and compared to the others. Preliminary results gathered indicate that the second algorithm of the three (APEA) offers the best balance of accuracy vs. execution time.
In summary, the solutions presented here solve the resource allocation problem for message delivery in a way that enables evaluation of real world communication scenarios.Master of Science
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Wu, Bin. "Algorithm design in optical networking." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39329161.
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Ajgaonkar, Prathamesh. "Simulation Studies on ZigBee Communications for Home Automation and Networking." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1289932769.
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Osborne, Delane Julia. "Social Influence Through Word-of-Mouth Communications in Social Networking." Thesis, Curtin University, 2018. http://hdl.handle.net/20.500.11937/75648.
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A study contributing to the existing literature by conceptualising a holistic model of the operation of word-of-mouth communications. Operationalized through a mixed methods research design, the study provides empirical evidence of the existence of influence from brand related word-of-mouth communications exchanged on social networking sites. Considering the impact of this influence on the consumption behaviours of individuals, results from the study have practical implications for marketing practitioners utilising social media as a marketing tool.
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Wu, Bin, and 吳斌. "Algorithm design in optical networking." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39329161.
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Velayos, Muñoz Héctor Luis. "Autonomic wireless networking." Doctoral thesis, KTH, School of Electrical Engineering (EES), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254.
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Large-scale deployment of IEEE 802.11 wireless LANs (WLANs) remains a significant challenge. Many access points (APs) must be deployed and interconnected without a-priori knowledge of the demand. We consider that the deployment should be iterative, as follows. At first, access points are deployed to achieve partial coverage. Then, usage statistics are collected while the network operates. Overloaded and under-utilized APs would be identified, giving the opportunity to relocate, add or remove APs. In this thesis, we propose extensions to the WLAN architecture that would make our vision of iterative deployment feasible.
One line of work focuses on self-configuration, which deals with building a WLAN from APs deployed without planning, and coping with mismatches between offered load and available capacity. Self-configuration is considered at three levels. At the network level, we propose a new distribution system that forms a WLAN from a set of APs connected to different IP networks and supports AP auto-configuration, link-layer mobility, and sharing infrastructure between operators. At the inter-cell level, we design a load-balancing scheme for overlapping APs that increases the network throughput and reduces the cell delay by evenly distributing the load. We also suggest how to reduce the handoff time by early detection and fast active scanning. At the intra-cell level, we present a distributed admission control that protects cells against congestion by blocking stations whose MAC service time would be above a set threshold.
Another line of work deals with self-deployment and investigates how the network can assist in improving its continuous deployment by identifying the reasons for low cell throughput. One reason may be poor radio conditions. A new performance figure, the Multi-Rate Performance Index, is introduced to measure the efficiency of radio channel usage. Our measurements show that it identifies cells affected by bad radio conditions. An additional reason may be limited performance of some AP models. We present a method to measure the upper bound of an AP’s throughput and its dependence on offered load and orientation. Another reason for low throughput may be excessive distance between users and APs. Accurate positioning of users in a WLAN would permit optimizing the location and number of APs. We analyze the limitations of the two most popular range estimation techniques when used in WLANs: received signal strength and time of arrival. We find that the latter could perform better but the technique is not feasible due to the low resolution of the frame timestamps in the WLAN cards.
The combination of self-configuration and self-deployment enables the autonomic operation of WLANs.
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Cheng, Xiaolu. "Efficient Information Dissemination in Vehicular Networks with Privacy Protection." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5560.
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Vehicular ad hoc network (VANET) is a key component of intelligent transportation System (ITS). In VANETs, vehicles and roadside units exchange information for the purpose of navigation, safe driving, entertainment and so on. The high mobility of vehicles makes efficient and private communications in VANETs a big challenge.
Improving the performance of information dissemination while protecting data privacy is studied in this research. Meet-Table based information dissemination method is first proposed, so as to improve the information dissemination, and to efficiently distribute information via utilizing roadside units, Cloud Computing, and Fog Computing. A clustering algorithm is proposed as well, to improve the stability for self-organized cluster-based dissemination in VANETs on highways.
Then, fuzzy neural networks are used to improve the stability and security of routing protocols, AODV, and design a novel protocol, GSS-AODV. To further protect data privacy, a multi-antenna based information protection approach for vehicle-to-vehicle(V2V) communications is also proposed.
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Holzer, Scott Walter. "DESIGN AND IMPLEMENTATION OF USER LEVEL SOCKET APPLICATION PROGRAMMING INTERFACE WITH SOCKET SPLITTING AND MEDIATION." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/403.
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Over the past few decades, the size and scope of the Internet has grown exponentially. In order to maintain support for legacy clients, new applications and services have been limited by dependence on traditional sockets and TCP, which provide no support for modifying endpoints after connection setup. This forces applications to implement their own logic to reroute communications to take advantage of composable services or handle failover. Some solutions have added socket operations that allow for endpoints to be redirected on the fly, but these have been limited in scope to handling failover and load balancing.
We present two new sets of socket operations. The first set allows servers to dynamically insert and remove intermediaries into communication streams. This allows applications to decide in real time whether to use services provided by 3rd parties such as encryption, filtering, and compression. In this way, applications can employ dynamic service composition to customize communication between clients and servers. The second set of operations allows sockets to be split such that all frames written to the socket are sent to multiple recipients. This is useful for implementing fast failover and passive communication monitoring. All of these operations are implemented in user space and gracefully handle legacy TCP clients, making quick deployment of distributed Internet applications a real possibility. Performance tests of the new operations on remote hosts show that the overhead introduced is not prohibitive.
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Mozaffari, Mohammad. "Wireless Communications and Networking with Unmanned Aerial Vehicles: Fundamentals, Deployment, and Optimization." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/83921.
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The use of aerial platforms such as unmanned aerial vehicles (UAVs), popularly known as drones, has emerged as a promising solution for providing reliable and cost-effective wireless communications. In particular, UAVs can be quickly and efficiently deployed to support cellular networks and enhance their quality-of-service (QoS) by establishing line-of-sight communication links. With their inherent attributes such as mobility, flexibility, and adaptive altitude, UAVs admit several key potential applications in wireless systems. Remarkably, despite these inherent advantages of UAVbased communications, little work has analyzed the performance tradeoffs associated with using UAVs as aerial wireless platforms. The key goal of this dissertation is to develop the analytical foundations for deployment, performance analysis, and optimization of UAV-enabled wireless networks. This dissertation makes a number of fundamental contributions to various areas of UAV communications that include: 1) Efficient deployment of UAVs, 2) Performance evaluation and optimization, and 3) Design of new flying, three-dimensional (3D) wireless systems. For deployment, using tools from optimization theory, holistic frameworks are developed for the optimal 3D placement of UAV base stations in uplink and downlink scenarios. The results show that the proposed deployment approaches significantly improve the downlink coverage for ground users, and enable ultra-reliable and energy-efficient uplink communications in Internet of Things (IoT) applications. For performance optimization, a novel framework is developed for maximizing the performance of a UAV-based wireless system, in terms of data service, under UAVs’ flight time constraints. To this end, using the mathematical framework of optimal transport theory, the optimal cell associations, that lead to a maximum data service to ground users within the limited UAVs’ hover duration, are analytically derived. The results shed light on the tradeoff between hover time and quality-of-service in UAV-based wireless networks. For performance evaluation, this dissertation provides a comprehensive analysis on the performance of a UAV-based communication system in coexistence with a terrestrial network. In particular, a tractable analytical framework is proposed for analyzing the coverage and rate performance of a network with a UAV base station and deviceto-device (D2D) users. The results reveal the fundamental tradeoffs in such a UAV-D2D network that allow adopting appropriate system design parameters. Then, this dissertation sheds light on the design of three new drone-enabled wireless systems. First, a novel framework for effective use of cache-enabled UAVs in wireless networks is developed. The results demonstrate how the users’ quality of experience substantially improves by exploiting UAVs’ mobility and user-centric information. Second, a new framework is proposed for deploying and operating a drone-based antenna array system that delivers wireless service to ground users within a minimum time. The results show significant enhancement in QoS, spectral and energy efficiency while levering the proposed drone antenna array system. Finally, to effectively incorporate various use cases of drones ranging from aerial users to base stations, the new concept of a fully-fledged 3D cellular network is introduced. For this new type of 3D wireless network, a unified framework for deployment, network planning, and performance optimization is developed that yields a maximum coverage and minimum latency in the network. In a nutshell, the analytical foundations and frameworks presented in this dissertation provide key guidelines for effective design and operation of UAV-based wireless communication systems.Ph. D.
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Rutabayiro, Ngoga Said. "On Dynamic Spectrum Access in Cognitive Radio Networking." Doctoral thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00568.
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The exploding increase of wireless communications combined with the existing inefficient usage of the licensed spectrum gives a strong impetus to the development and standardization of cognitive radio networking and communications. In this dissertation, a framework for Dynamic Spectrum Access (DSA) is first presented, which is the enabling technology for increasing the spectral efficiency of wireless communications. Based on that, Cognitive Radio (CR) can be developed as an enabling technology for supporting the DSA, which means that the wireless users are provided with enhanced capability for sensing the operating radio environment and for exploiting the network side information obtained from this sensing. The DSA concept means that the users of a wireless system are divided into a multi-tiered hierarchy with the primary users (PUs) entitled to protection and with cognitive radio capable secondary users (SUs). The improved spectrum efficiency is obtained by means of a medium access control protocol with knowledge about the statistical properties or available local information of the channels already occupied by PUs as well as knowledge about the interference tolerance within which the interference to PUs is kept to a given level. Related to this, emphasis is laid on the protocol capability to determine the efficiency of the secondary sharing of spectrum. Based on the type of available local information, the capacity of opportunistic communication is investigated for three models. These are: with dynamic, distributed channels information; with dynamic, parallel channels information; and under a dynamic sub-channels allocation scheme. The results indicate that this capacity is robust with reference to the uncertainty associated with localized sensing of distributed dynamic channels and with timely sensing of parallel dynamic channels. The extension to dynamic parallel sub-channels enables resource allocation to be carried out in sub-channels. The analytical results on the performance of sub-channel allocation indicate a robust traffic capacity in terms of blocking probability, drop-out probability and delay performance as function of PUs traffic loads.
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Davis, Don, Toby Bennett, and Jay Costenbader. "RECONFIGURABLE GATEWAY SYSTEMS FOR SPACE DATA NETWORKING." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/608358.
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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaOver a dozen commercial remote sensing programs are currently under development representing billions of dollars of potential investment. While technological advances have dramatically decreased the cost of building and launching these satellites, the cost and complexity of accessing their data for commercial use are still prohibitively high. This paper describes Reconfigurable Gateway Systems which provide, to a broad spectrum of existing and new data users, affordable telemetry data acquisition, processing and distribution for real-time remotely sensed data at rates up to 300 Mbps. These Gateway Systems are based upon reconfigurable computing, multiprocessing, and process automation technologies to meet a broad range of satellite communications and data processing applications. Their flexible architecture easily accommodates future enhancements for decompression, decryption, digital signal processing and image / SAR data processing.
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Gaber, Donald H. "Analyzing the effectiveness of illustrations in information and communications technologies (networking emphasis) textbooks." Menomonie, WI : University of Wisconsin--Stout, 2007. http://www.uwstout.edu/lib/thesis/2007/2007gaberd.pdf.
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Kalim, Umar. "Cognizant Networks: A Model and Framework for Session-based Communications and Adaptive Networking." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/87387.
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The Internet has made tremendous progress since its inception. The kingpin has
been the transmission control protocol (TCP), which supports a large fraction of
communication. With the Internet's wide-spread access, users now have increased
expectations.
The demands have evolved to an extent which TCP was never
designed to support. Since network stacks do not provide the necessary
functionality for modern applications, developers are forced to implement them
over and over again --- as part of the application or supporting libraries.
Consequently, application developers not only bear the burden of developing
application features but are also responsible for building networking libraries
to support sophisticated scenarios. This leads to considerable duplication of
effort.
The challenge for TCP in supporting modern use cases is mostly due to limiting
assumptions, simplistic communication abstractions, and (once expedient)
implementation shortcuts. To further add to the complexity, the limited TCP
options space is insufficient to support extensibility and thus, contemporary
communication patterns. Some argue that radical changes are required to extend
the networks functionality; some researchers believe that a clean slate approach
is the only path forward. Others suggest that evolution of the network stack is
necessary to ensure wider adoption --- by avoiding a flag day. In either case,
we see that the proposed solutions have not been adopted by the community at
large. This is perhaps because the cost of transition from the incumbent to the
new technology outweighs the value offered. In some cases, the limited scope of the
proposed solutions limit their value. In other cases, the lack of backward
compatibility or significant porting effort precludes incremental adoption
altogether.
In this dissertation, we focus on the development of a communication model that
explicitly acknowledges the context of the conversation and describes (much of)
modern communications. We highlight how the communication stack should be able
to discover, interact with and use available resources to compose richer
communication constructs. The model is able to do so by using session,
flow and endpoint abstractions to describe communications between
two or more endpoints. These abstractions provide means to the application
developers for setting up and manipulating constructs, while the ability to
recognize change in the operating context and reconfigure the constructs allows
applications to adapt to the changing requirements. The model considers two or
more participants to be involved in the conversation and thus enables most
modern communication patterns, which is in contrast with the well-established
two-participant model.
Our contributions also include an implementation of a framework that realizes
such communication methods and enables future innovation. We substantiate our
claims by demonstrating case studies where we use the proposed abstractions to
highlight the gains. We also show how the proposed model may be implemented in a
backwards compatible manner, such that it does not break legacy applications,
network stacks, or middleboxes in the network infrastructure. We also present
use cases to substantiate our claims about backwards compatibility. This
establishes that incremental evolution is possible. We highlight the benefits
of context awareness in setting up complex communication constructs by
presenting use cases and their evaluation. Finally, we show how the
communication model may open the door for new and richer communication patterns.PHD
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Lydon, Sean Michael. "General Direction Routing Protocol." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/97.
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The General Direction Routing Protocol (GDRP) is a Wireless Sensor Network (WSN)
multi-path routing protocol which abstracts localization information (commonly GPS
coordinates) into relative direction information in order to perform routing decisions. By
generating relative direction information GDRP is able to operate with fewer precision
requirements than other protocols. This abstraction also allows the integration of other emerging
hardware-based localization techniques, for example, Beamforming Sensor Arrays.
GDRP does not specifically address the next hop a packet should take, but instead specifies a
direction it should travel. This direction abstraction allows for multiple paths to be taken through
the network thus enhancing network robustness to node mobility and failures. This indirect
addressing scheme also provides a solution to sensor node unique identification.
GDRP is simulated in a custom simulator written in Java. This simulator supports interfaces
for multiple protocols for layers 1, 2, 3, and 7 of the OSI model. For performance comparisons,
GDRP is compared against multiple WSN routing protocols. GDRP operates with a significantly
lower setup cost in terms of bytes transmitted and a lower setup latency for networks of varying
sizes. It also demonstrates an exponentially lower routing cost when compared to another multi-
path routing protocol due to a more efficient packet propagation in the network.
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El, Moutia Abdallah. "Energy-aware Ad Hoc on-demand distance vector routing protocol and optimizing the blocking problem induced in wireless Ad Hoc networks." FIU Digital Commons, 2004. http://digitalcommons.fiu.edu/etd/3124.
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The purpose of this thesis was to investigate some of the issues related to routing and medium access control protocol in ad hoc networks. In routing protocol, the goal is to tackle the power consumption problem and to present a case for using new cost energy-aware metric for Ad Hoc On-Demand Distance Vector (AODV). The idea of the new cost metric is to be able to avoid routes with a low energy capacity. By using this approach, high efficiency in energy consumption can be achieved in Ad-Hoc networks.
The second goal of this thesis was to investigate the blocking problem induced by Request-to-Send/Clear-to-Send (RTS/CTS) mechanism in detail and provide a solution to overcome that problem. To do so, a new parameter is proposed by which the Medium Access control (MAC) protocol will decide when to switch between RTS/CTS mechanism (the 4-way-handshaking) and the Basic Access method (the 2-way-handshaking) in order to reduce the effect of the blocking problem in Ad Hoc networks.
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Hachfi, Fakhreddine Mohamed. "Future of asynchronous transfer mode networking." CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2639.
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The growth of Asynchronous Transfer Mode (ATM) was considered to be the ideal carrier of the high bandwidth applications like video on demand and multimedia e-learning. ATM emerged commercially in the beginning of the 1990's. It was designed to provide a different quality of service at a speed up 100 Gbps for both real time and non real time application. The turn of the 90's saw a variety of technologies being developed. This project analyzes these technologies, compares them to the Asynchronous Transfer Mode and assesses the future of ATM.
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Carter, Noah. "Building Data Visualization Applications to Facilitate Vehicular Networking Research." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/honors/459.
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A web app was developed which allows any internet-connected device to remotely monitor a roadway intersection’s state over HTTP. A mapping simulation was enhanced to allow researchers to retroactively track the location and the ad-hoc connectivity of vehicle clusters. A performance analysis was conducted on the utilized network partitioning algorithm. This work was completed under and for the utility of ETSU’s Vehicular Networking Lab. It can serve as a basis for further development in the field of wireless automobile connectivity.
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Lepère, Renaud. "Approches algorithmiques pour l'ordonnancement d'applications parallèles avec communications." Phd thesis, Grenoble INPG, 2001. http://tel.archives-ouvertes.fr/tel-00010476.
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Cette thèse est consacrée à l'étude de l'ordonnancement des tâches d'un programme parallèle en prenant en compte l'impact des communications. Sur les machines à mémoire distribuée telles que les grappes de PC, les temps de communications peuvent être importants. Les objectifs de cette thèse sont l'étude de modèles permettant de prendre en compte efficacement ces communications et l'étude des problèmes d'ordonnancement sous ces modèles. Nous nous sommes interessés au modèle à grand délai de communications qui est basé sur une prise en compte explicite des communications et au modèle des tâches malléables dans lequel les tâches sont elles-mêmes des activités parallèles pouvant s'exécuter sur un nombre variable de processeurs. Outre l'étude de la pertinance de ces modèles, les contributions obtenues vont dans les trois directions suivantes. Pour l'ordonnancement de tâches malléables avec contraintes de précédence nous avons proposé des algorithmes d'approximation constante (algorithmes polynômiaux offrant des garanties relativement à une solution optimale), pour le cas des arbres et pour le cas d'un graphe de précedence arbitraire. Une heuristique originale pour le problème du regroupement (ordonnancement sur un nombre non borné de processeurs) est proposée. Elle est basée sur une décomposition récursive du graphe de précédence et elle est validée par des simulations sur des graphes d'applications réelles. Enfin nous nous sommes intéressés au problème d'ordonnancement sous le modèle à grand délai de communication en considérant la possibilité de dupliquer des tâches. Dans ce cadre nous avons obtenu un algorithme polyôomial offrant une garantie logarithmique en fonction du délai de communication, améliorant ainsi la meilleure garantie connue (linéaire).
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Bommer, John S. "Joint networking command and control (C2) communications among Distributed Operations, JCAS, and Joint Fires." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FBommer.pdf.
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Thesis (M.S. in Systems Technology (Command, Control, and Communications (C3))--Naval Postgraduate School, June 2007.Thesis Advisor(s): Rex Buddenberg, Carl Oros. "June 2007." Includes bibliographical references (p. 77-80). Also available in print.
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Masacioglu, Mustafa, and Marlon McBride. "Control Based Mobile Ad Hoc Networking for survivable, dynamic, mobile Special Operation Force communications." Thesis, Monterey, California: Naval Postgraduate School, 2009. http://hdl.handle.net/10945/4592.
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Approved for public release, distribution unlimitedIn the next generation of wireless communication systems, there will be a need for the rapid deployment of independent mobile users. Significant examples include establishing survivable, efficient, dynamic mobile communication for tactical Special Operation Force (SOF) networks, as well as SOF units that are ad hoc networking with first responders conducting emergency/rescue and disaster relief operations. Such network scenarios cannot rely on centralized and organized connectivity, and should instead employ applications of newly developing Control Based Mobile Ad Hoc Networking (CBMANET). In a CBMANET environment, an autonomous collection of mobile users communicate over relatively bandwidth constrained wireless links by taking benefit of nodes mobility and topology control in combination with mobile platform switching. The network is decentralized. All network activity, including discovering the topology and delivering messages, must be executed by the nodes themselves (i.e., routing functionality will be incorporated into mobile nodes). Harnessing the tremendous flexibility and efficiency of CBMANET would allow for better control and protection of ad hoc mobile networks. Therefore, we need to work tirelessly to improve our capabilities in the three aforementioned control spaces.
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Rong, Sike. "Networking Communications for a Collective Retailing District of Small Scale Brick-And-Mortar Stores." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1593171660317983.
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McBride, Marlon Masacioglu Mustafa. "Control Based Mobile Ad Hoc Networking for survivable, dynamic, mobile Special Operation Force communications." Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FMcBride.pdf.
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Thesis (M.S. in Information Technology Management)--Naval Postgraduate School, September 2009.Thesis Advisor(s): Bordetsky, Alex. "September 2009." Description based on title screen as viewed on November 5, 2009. Author(s) subject terms: Control Based Mobile Ad Hoc Networking, CBMANET, MANET, Routing Protocol, Wireless Network Includes bibliographical references (p. 67-72). Also available in print.
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Rivera, Polanco Sergio A. "AUTOMATED NETWORK SECURITY WITH EXCEPTIONS USING SDN." UKnowledge, 2019. https://uknowledge.uky.edu/cs_etds/87.
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Campus networks have recently experienced a proliferation of devices ranging from personal use devices (e.g. smartphones, laptops, tablets), to special-purpose network equipment (e.g. firewalls, network address translation boxes, network caches, load balancers, virtual private network servers, and authentication servers), as well as special-purpose systems (badge readers, IP phones, cameras, location trackers, etc.). To establish directives and regulations regarding the ways in which these heterogeneous systems are allowed to interact with each other and the network infrastructure, organizations typically appoint policy writing committees (PWCs) to create acceptable use policy (AUP) documents describing the rules and behavioral guidelines that all campus network interactions must abide by.
While users are the audience for AUP documents produced by an organization's PWC, network administrators are the responsible party enforcing the contents of such policies using low-level CLI instructions and configuration files that are typically difficult to understand and are almost impossible to show that they do, in fact, enforce the AUPs. In other words, mapping the contents of imprecise unstructured sentences into technical configurations is a challenging task that relies on the interpretation and expertise of the network operator carrying out the policy enforcement. Moreover, there are multiple places where policy enforcement can take place. For example, policies governing servers (e.g., web, mail, and file servers) are often encoded into the server's configuration files. However, from a security perspective, conflating policy enforcement with server configuration is a dangerous practice because minor server misconfigurations could open up avenues for security exploits. On the other hand, policies that are enforced in the network tend to rarely change over time and are often based on one-size-fits-all policies that can severely limit the fast-paced dynamics of emerging research workflows found in campus networks.
This dissertation addresses the above problems by leveraging recent advances in Software-Defined Networking (SDN) to support systems that enable novel in-network approaches developed to support an organization's network security policies. Namely, we introduce PoLanCO, a human-readable yet technically-precise policy language that serves as a middle-ground between the imprecise statements found in AUPs and the technical low-level mechanisms used to implement them. Real-world examples show that PoLanCO is capable of implementing a wide range of policies found in campus networks. In addition, we also present the concept of Network Security Caps, an enforcement layer that separates server/device functionality from policy enforcement. A Network Security Cap intercepts packets coming from, and going to, servers and ensures policy compliance before allowing network devices to process packets using the traditional forwarding mechanisms. Lastly, we propose the on-demand security exceptions model to cope with the dynamics of emerging research workflows that are not suited for a one-size-fits-all security approach. In the proposed model, network users and providers establish trust relationships that can be used to temporarily bypass the policy compliance checks applied to general-purpose traffic -- typically by network appliances that perform Deep Packet Inspection, thereby creating network bottlenecks. We describe the components of a prototype exception system as well as experiments showing that through short-lived exceptions researchers can realize significant improvements for their special-purpose traffic.
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Boppana, Neelima. "Simulation and analysis of network traffic for efficient and reliable information transfer." FIU Digital Commons, 2002. http://digitalcommons.fiu.edu/etd/1732.
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With the growing commercial importance of the Internet and the development of new real-time, connection-oriented services like IP-telephony and electronic commerce resilience is becoming a key issue in the design of TP-based networks. Two emerging technologies, which can accomplish the task of efficient information transfer, are Multiprotocol Label Switching (MPLS) and Differentiated Services. A main benefit of MPLS is the ability to introduce traffic-engineering concepts due to its connection-oriented characteristic. With MPLS it is possible to assign different paths for packets through the network. Differentiated services divides traffic into different classes and treat them differently, especially when there is a shortage of network resources. In this thesis, a framework was proposed to integrate the above two technologies and its performance in providing load balancing and improving QoS was evaluated. Simulation and analysis of this framework demonstrated that the combination of MPLS and Differentiated services is a powerful tool for QoS provisioning in IP networks.
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Delgado, Javier. "A grid computing network platform for enhanced data management and visualization." FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/2766.
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This thesis presents a novel approach towards providing a collaboration environment by using Grid Computing. The implementation includes the deployment of a cluster attached to a mural display for high performance computing and visualization and a Grid-infrastructure for sharing storage space across a wide area network and easing the remote use of the computing resources. A medical data processing application is implemented on the platform. The outcome is enhanced use of remote storage facilities and quick return time for computationally-intensive problems.
The central issue of this thesis work is thus one that focuses on the development of a secure distributed system for data management and visualization to respond to the need for more efficient interaction and collaboration between technical researchers and medical professionals. The proposed networked solution is envisioned such as to provide synergy for more collaboration on theoretical and experimental issues involving analysis, visualization, and data sharing across sites.
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Doshi, Abhay. "Fault/configuration management for wireless ad-hoc network." FIU Digital Commons, 2002. http://digitalcommons.fiu.edu/etd/3081.
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An ad hoc network is maintained by the combined efforts of all the mobile nodes themselves, who often operate under severe constraints, such as limited battery power, variable link quality, and limited storage capacity. As a result, there is a growing need for enhanced fault and configuration management solutions to help in tracking problems as well as solving them.
Viable network architecture for a wireless ad-hoc environment, which takes advantages of both hierarchical and distributed architectures, has been investigated. A complete design solution is proposed which makes ad-hoc environments less susceptible to faults. Results shows that by applying the proposed power saving technique, network load due to control traffic may be significantly reduced. Based on other gathered statistics, we can set the optimal value of maximum number of nodes allowed in a cluster for efficient performance to be 35 for a specific scenario.
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Bouassida, Mohamed Salah. "Sécurité des communications de groupe dans les réseaux ad hoc." Phd thesis, Université Henri Poincaré - Nancy I, 2006. http://tel.archives-ouvertes.fr/tel-00134732.
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La transmission multicast est un mécanisme efficace de communication pour des applications, telles que les vidéos conférences, les jeux interactifs et la distribution de logiciels orientés groupe. L'avantage principal des communications multicast est d'optimiser la consommation des ressources de réseaux, principalement en réduisant la consommation de la bande passante et des ressources des routeurs.En parallèle avec le développement des services multicast dans l'Internet, la dernière décennie a vu l'émergence des réseaux ad hoc, grâce à l'apparition de nouvelles technologies sans fil et de nouvelles normes (par exemple 802.11, Wimax, ...). Un réseau ad hoc est une collection dynamique de dispositifs, autonomes, reliés sans aucune infrastructure fixe, qui peut être fortement mobile.
La combinaison d'un environnement ad hoc avec des services multicast à déployer, a induit de nouveaux défis envers l'infrastructure de sécurité requise pour un large déploiement des communications multicast dans un tel environnement. C'est dans ce cadre que nous avons défini deux protocoles de gestion de clé de groupe dans les MANETs, un protocole orienté récepteurs, appelé Enhanced BAAL et un protocole orienté sources, dénommé BALADE. Nous avons également proposé OMCT : un algorithme de clusterisation dynamique du groupe multicast, que nous avons intégré dans BALADE. Ce couplage assure une distribution de clés efficace et rapide, tenant compte de la mobilité et de la localisation des nœuds, tout en optimisant la consommation de l'énergie et de la bande passante. L'applicabilité de BALADE couplé avec OMCT est démontrée à travers sa validation formelle avec l'outil AVISPA, son implantation dans le cadre d'une application de Jukebox coopérative, et l'évaluation de ses performances avec l'outil de simulation de réseaux NS2.
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Martínez-Vidal, Rubén. "Architectures for aeronautical opportunistic networking." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/319697.
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En els últims anys, el camp de les comunicacions aeronàutiques ha experimentat un increment en la demanda d'intercanvis de dades entre plataformes terrestres, aèries i satelitals. Els mètodes de comunicació aeronàutics convencionals han demostrat no ser suficients per manejar aquesta demanda creixent. Com a resultat, els sistemes aeronàutics han tendit cap a l'ús de comunicacions via satèl·lit, que encara que efectives, suposen un repte econòmic tant en la seva instal·lació com en el seu ús. En resposta a aquest problema, el treball acadèmic en aquesta àrea ha proposat l'ús d'alternatives basades en xarxes de comunicació en la forma de xarxes aeronàutiques ad-hoc. Aquestes xarxes usen abastos de comunicació immensos i treballen sota la premissa de les Xarxes Ad-Hoc Mòbils (MANETs) requerint l'existència de connectivitat extrem a extrem per al seu correcte funcionament. Les xarxes aeronàutiques tenen una topologia extremadament variable juntament amb enllaços de comunicació poc fiables. Amb aquestes propietats en ment, creiem que assumir connectivitat de xarxa és una elecció desafortunada. Per tant, en aquesta tesi intentem solucionar aquests reptes utilitzant un enfocament diferent. Específicament, intentarem establir una xarxa d'avions sense assumir garanties de connectivitat, enllaços de radi curts i utilitzant tan sol les trobades esporàdiques entre nodes per realitzar intercanvi de dades. Aquest enfocament oportunista ofereix una alternativa més barata que aquelles basades en enllaços de radi de llarg abast o en comunicacions via satèl·lit. Els fonaments d'aquesta proposta es basen a les xarxes oportunistes, i eventualment s'uneixen amb la tendència actual d'utilitzar enllaços via satèl·lit, per oferir una nova arquitectura de xarxa que redueix àmpliament els costos de comunicació i equipament. Les principals contribucions d'aquesta tesi són les següents. D'una banda, l'ús d'un model de mobilitat precís descrivint patrons aeronàutics basats en informació i horaris de vol reals. A més, aquest treball utilitza un model minuciós per descriure les capacitats de xarxa dels nodes incloent la representació completa de totes les capes de xarxa. Aquestes característiques realistes són molt importants per assegurar el correcte desplegament en xarxes reals. D'altra banda, aquesta tesi ofereix una sèrie de garanties en la qualitat de servei que són difícils d'obtenir en xarxes oportunistes. Fins a on sabem aquesta tesi representa el primer estudi detallat d'una xarxa aeronàutica a gran escala utilitzant comunicacions oportunistes.En los últimos años, el campo de las comunicaciones aeronáuticas ha experimentado un incremento masivo de los intercambios de datos entre plataformas terrestres, aéreas y satelitales. Los métodos de comunicación aeronáuticos convencionales han demostrado no ser suficientes para manejar esta demanda creciente. Como resultado, los sistemas aeronáuticos han tendido hacia el uso de comunicaciones vía satélite, que aunque efectivas, suponen un reto económico tanto en su instalación como en su uso. En respuesta a este problema, el trabajo académico en esta área ha propuesto el uso de alternativas basadas en redes de comunicación en la forma de redes aeronáuticas ad-hoc. Estas redes usan alcances de comunicación inmensos y trabajan bajo la premisa de las Redes Ad-Hoc Móviles (MANETs) requiriendo la existencia de conectividad extremo a extremo para su correcto funcionamiento. Las redes aeronáuticas tienen una topología extremadamente variable juntamente con enlaces de comunicación poco fiables. Con estas propiedades en mente, creemos que asumir conectividad de red es una elección desafortunada. Por tanto, en esta tesis intentamos solucionar estos retos utilizando un enfoque diferente. Específicamente, intentaremos establecer una red de aviones sin asumir garantías de conectividad, enlaces de radio cortos y utilizando tan solo los encuentros esporádicos entre nodos para realizar intercambio de datos. Este enfoque oportunista ofrece una alternativa más barata que aquellas basadas en enlaces de radio de largo alcance o en comunicaciones vía satélite. Los fundamentos de esta propuesta se basan en las redes oportunistas, y eventualmente se unen con la tendencia actual de utilizar enlaces vía satélite, para ofrecer una nueva arquitectura de red que reduce ampliamente los costes de comunicación y equipamiento. Las principales contribuciones de esta tesis son las siguientes. Por un lado, el uso de un modelo de movilidad preciso describiendo patrones aeronáuticos basados en información y horarios de vuelo reales. Además, este trabajo utiliza un modelo minucioso para describir las capacidades de red de los nodos incluyendo la representación completa de todas las capas de red. Estas características realistas son muy importantes para asegurar el correcto despliegue en redes reales. Por otro lado, esta tesis ofrece una serie de garantías en la calidad de servicio que son difíciles de obtener en redes oportunistas. Hasta donde sabemos esta tesis representa el primer estudio detallado de una red aeronáutica a gran escala utilizando comunicaciones oportunistas.
In recent years, the aeronautical communications field has experienced increased demand for data exchanges between terrestrial, aerial and satellite platforms. Conventional aeronautical communications have proven to fall short on handling this growing demand. As a result, aeronautical systems have moved towards the use of satellite-based communications, and while effective, their deployment and later use poses an economical challenge. To deal with this problem, academic work on the topic has proposed the use of networking alternatives in the form of Aeronautical Ad-hoc Networks. These networks use large radio communication ranges and work on the premises of Mobile Ad-Hoc Networks (MANET), requiring end-to-end connectivity to function properly. Aeronautical networks have an extremely varying topology coupled with a frequently unreliable communication channel. With this in mind, we think that assuming full network connectivity is a problematic choice. Therefore, in this thesis we will approach those problems using a different method. Specifically, we will strive to establish a network of aircraft assuming no guarantees for connectivity, limited radio ranges, and relying solely on the sporadic encounters between nodes to perform data exchanges. This opportunistic approach offers a cheaper solution than those based on long-range radio links or satellite communications. The foundation of this proposal lies in opportunistic networks, and eventually merges with the current communication trend based on satellite links, to provide a new network infrastructure that greatly minimizes communication costs and equipment expenditure. The main contributions of this thesis are as follows. On one hand, the use of an accurate mobility model describing aeronautical patterns by considering on flight route and scheduling information of real flights. Additionally, this work provided accurate modeling of the network capabilities of each node including the complete representation of all layers of the network stack. These realistic features are of severe importance to ensure successful deployment in real networks. On the other hand, this thesis provides Quality of Service assurances that are hard to achieve in opportunistic networking. To the best of our knowledge, this thesis represents the first in-depth analysis of a realistic large-scale aeronautical opportunistic network.
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Makasiranondh, Woratat. "An investigation into internetworking education." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2011. https://ro.ecu.edu.au/theses/462.
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Computer network technology and the Internet grew rapidly in recent years. Their growth created a large demand from industry for the development of IT and internetworking professionals. These professionals need to be equipped with both technical hands-on skills and non-technical or soft skills. In order to supply new professionals to the industry, educational institutions need to address these skills training in their curricula. Technical hands-on skills in internetworking education can be emphasised through the practical use of equipment in classrooms. The provision of the networking equipment to the internetworking students is a challenge. Particularly, university students in developing countries may find that this equipment is ineffectively provided by their teaching institutions, because of the expense. Modern online learning tools, such as remote access laboratories, may be used to address this need. However, the provision of such tools will also need to concentrate upon the pedagogical values. In addition, traditional remote access laboratories provide only text-based access, which was originally designed for highly professional use. Novice students may struggle with learning in these virtual environments, especially when the physical equipment is not available locally. Furthermore, non-technical skills or soft skills are social skills that should not be neglected in graduates’ future workplaces. A traditional model of developing soft skills that was used in face-to-face classroom may not be as effective when applied in an online classroom. Research on students’ opinions about their soft skills development during attending internetworking courses is needed to be conducted. In order to address both research needs, this study was focused on two research aspects related to online learning in internetworking education. The first focus was on research into providing a suitable technical learning environment to distance internetworking students. The second focus was on the students’ opinions about their non-technical skills development. To provide a close equivalent of a face-to-face internetworking learning environment to remote students in Thailand, a transformation of a local internetworking laboratory was conducted. A new multimedia online learning environment integrated pedagogically-rich tools such as state model diagrams (SMDs), a real-time video streaming of equipment and a voice communication tool. Mixed research data were gathered from remote online and local student participants. The remote online participants were invited to use the new learning environment developed in this study. Qualitative research data were collected from twelve remote online students after their trial usage. Concurrently, another set of research data were collected from local students asking their opinion about the development of soft skills in the internetworking course. There were sixty six participants in this second set of research data. Although the research data was limited, restricting the researcher’s ability to generalise, it can be concluded that the provision of multimedia tools in an online internetworking learning environment was beneficial to distant students. The superiority of the traditional physical internetworking laboratory cannot be overlooked; however, the remote laboratory could be used as a supplementary self-practice tool. A concrete learning element such as a real-time video stream and diagrams simplified students learning processes in the virtual environment. Faster communication with the remote instructors and the equipment are also critical factors for a remote access network to be successful. However, unlike the face-to-face laboratory, the future challenge of the online laboratory will creating materials which will encourage students to build soft skills in their laboratory sessions.
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Clevenger, Bryan. "HIDRA: Hierarchical Inter-Domain Routing Architecture." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/292.
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As the Internet continues to expand, the global default-free zone (DFZ) forwarding table has begun to grow faster than hardware can economically keep pace with. Various policies are in place to mitigate this growth rate, but current projections indicate policy alone is inadequate. As such, a number of technical solutions have been proposed. This work builds on many of these proposed solutions, and furthers the debate surrounding the resolution to this problem. It discusses several design decisions necessary to any proposed solution, and based on these tradeoffs it proposes a Hierarchical Inter-Domain Routing Architecture - HIDRA, a comprehensive architecture with a plausible deployment scenario. The architecture uses a locator/identifier split encapsulation scheme to attenuate both the immediate size of the DFZ forwarding table, and the projected growth rate. This solution is based off the usage of an already existing number allocation policy - Autonomous System Numbers (ASNs). HIDRA has been deployed to a sandbox network in a proof-of-concept test, yielding promising results.
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Bernard, Nicolas. "Non-observabilité des communications à faible latence." Phd thesis, Université Joseph Fourier (Grenoble), 2008. http://tel.archives-ouvertes.fr/tel-00325234.
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Cette thèse s'articule autour de deux parties, toutes deux liées à la protection de la vie privée dans les réseaux informatiques en général et sur l'Internet en particulier.Dans la première partie, nous proposons un système permettant d'établir des communications interactives non-observables, c'est-à-dire telles qu'un observateur ne puisse pas déterminer vers quelle(s) destination(s) sont établies ces communications, ni même, en fait, être certain qu'il y a bien de vraies communications!
Ce système innove par le niveau de protection qu'il vise, puisque même un observateur très puissant ne devrait pas être à même de la contourner.
Cette protection se base sur l'Onion-Routing et le complète avec des méthodes sophistiquées destinées à déjouer l'analyse de trafic.
Dans la seconde partie, nous nous intéressons plus particulièrement au protocole DNS.
Bien qu'il soit possible de le protéger avec notre proposition de la partie précédente, cela dégrade ses performances (en termes de latence), ce qui à son tour a un impact sur celles des protocoles qui utilisent DNS.
Dans cette partie, nous proposons une solution spécifique à DNS, qui fournit à la fois un bon niveau de protection et de meilleures performances.
Ces deux systèmes peuvent bien sûr se combiner, mais aussi être utilisés comme des briques séparées, avec d'autre mécanismes de protection de la vie privée.
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Aguilar, Melchior Carlos. "Les communications anonymes à faible latence." Phd thesis, INSA de Toulouse, 2006. http://tel.archives-ouvertes.fr/tel-00110313.
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Dans ce mémoire nous proposons des systèmes de communication anonyme à faible latence. Pour cela nous étudions les performances des systèmes basés sur les primitives classiques : envoi superposé ou bourrage chiffré pour l'émission, et diffusion avec adressage implicite pour la réception, quand les groupes d'utilisateurs potentiels sont contraints à être de petite taille, peu changeants, ou localisés. Nous proposons l'utilisation des protocoles de récupération d'informations privée (ou protocoles PIR pour Private Information Retrieval) comme alternative à la diffusion avec adressage implicite, et nous étudions les systèmes en résultant. Ces systèmes permettent de réduire significativement le coût des communications, au prix d'un coût calculatoire important. Au moyen d'exemples, nous montrons que ces nouvelles solutions offrent un meilleur choix dans certaines situations, notamment pour les utilisateurs connectés au service par Internet. Dans un deuxième temps, nous mettons en avant les relations entre les différentes techniques et montrons que les systèmes basés sur les primitives classiques ne sont en fait que des instances d'une famille qui, par l'utilisation de la récupération d'informations privée, devient nombreuse et polyvalente. Ainsi, on dispose de beaucoup plus de degrés de liberté pour l'implémentation de solutions fournissant des communications anonymes dans le cadre des groupes d'utilisateurs sous contraintes.
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Reid, Robert J., and Nancy Callaghan. "Twenty-First Century Live Play - Recent Developments." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611413.
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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThe 21st Century Live Play (21CLP) program is developing a mobile, low cost, wireless networking system that supports applications to provide a number of services for military use. 21CLP is a joint Defense Advanced Research Projects Agency (DARPA) and Central Test and Evaluation Investment Program (CTEIP) project. The Naval Undersea Warfare Center, Division Newport (NUWCDIVNPT), Code 382 has been assigned as the program manager for a T&E version of the 21CLP system. The 21CLP vision is a common instrumentation function that links, in real-time, live land, air and maritime entities together with a virtual battlespace in any location where forces are deployed or being trained, weapons systems are being tested and evaluated, and ultimately where missions are being conducted. This vision will be realized with an embedded, mobile, distributed, untethered system that requires little or no site preparation.
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Kurtz, Fabian Markus [Verfasser]. "Design and Performance Evaluation of Adaptive Critical Infrastructure Communications based on Software-Defined Networking / Fabian Markus Kurtz." Düren : Shaker, 2021. http://d-nb.info/1240583982/34.
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Jiang, Qiangfeng. "ALGORITHMS FOR FAULT TOLERANCE IN DISTRIBUTED SYSTEMS AND ROUTING IN AD HOC NETWORKS." UKnowledge, 2013. http://uknowledge.uky.edu/cs_etds/16.
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Checkpointing and rollback recovery are well-known techniques for coping with failures in distributed systems. Future generation Supercomputers will be message passing distributed systems consisting of millions of processors. As the number of processors grow, failure rate also grows. Thus, designing efficient checkpointing and recovery algorithms for coping with failures in such large systems is important for these systems to be fully utilized. We presented a novel communication-induced checkpointing algorithm which helps in reducing contention for accessing stable storage to store checkpoints. Under our algorithm, a process involved in a distributed computation can independently initiate consistent global checkpointing by saving its current state, called a tentative checkpoint. Other processes involved in the computation come to know about the consistent global checkpoint initiation through information piggy-backed with the application messages or limited control messages if necessary. When a process comes to know about a new consistent global checkpoint initiation, it takes a tentative checkpoint after processing the message. The tentative checkpoints taken can be flushed to stable storage when there is no contention for accessing stable storage. The tentative checkpoints together with the message logs stored in the stable storage form a consistent global checkpoint.
Ad hoc networks consist of a set of nodes that can form a network for communication with each other without the aid of any infrastructure or human intervention. Nodes are energy-constrained and hence routing algorithm designed for these networks should take this into consideration. We proposed two routing protocols for mobile ad hoc networks which prevent nodes from broadcasting route requests unnecessarily during the route discovery phase and hence conserve energy and prevent contention in the network. One is called Triangle Based Routing (TBR) protocol. The other routing protocol we designed is called Routing Protocol with Selective Forwarding (RPSF). Both of the routing protocols greatly reduce the number of control packets which are needed to establish routes between pairs of source nodes and destination nodes. As a result, they reduce the energy consumed for route discovery. Moreover, these protocols reduce congestion and collision of packets due to limited number of nodes retransmitting the route requests.
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Guercio, Remy. "Exploring Radio Frequency Positioning Methods and Their Use in Determining User Context in Public Spaces." Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/cmc_theses/1441.
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RF positioning methods have various tradeoffs that make them suitable for differing applications. This thesis identifies the most prominent positioning methods and deter-mines their suitability for context aware applications in pub-lic spaces using a number of different factors. This thesis first explores the physical characteristics of GPS, GSM, 802.11 and Bluetooth focusing on coverage and accuracy in both a historical and forward looking context. Next, it explores what it means for an application to be context aware and how that translates into building applications that are used in the context of public places. This thesis then reflects on the intersection of the two and explores some challenges related to practical implementations. In order to further explore these challenges, it assesses a high accuracy use case of merging Bluetooth positioning with augmented reality and virtual reality applications. We find that in the last decade Bluetooth has made rapid advancements in relation to competing technologies, but it is still far from ideal in all situations, especially when the situation requires extremely high accuracy.
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Laverty, Calvin Andrew. "Multi-Vector Tracking of WiFi and Zigbee Devices." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2047.
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Location privacy preservation has shifted to the forefront of discussions about next generation wireless networks. While pseudonym-changing schemes have been proposed to preserve an individual's privacy, simulation has shown that new association attack models render these schemes useless. The major contribution of this thesis is the implementation of a tracking network with commodity hardware on the California Polytechnic State University campus which leverages the combination of de-anonymization strategies on captured wireless network data to show the effectiveness of a pseudonym-changing scheme for wireless identification across WiFi and Zigbee protocols.
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Zhou, Liang. "Recherche sur les techniques clés pour les communications multimédias dans les Ad-Hoc réseaux." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2009. http://tel.archives-ouvertes.fr/tel-00506045.
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Dans cette thèse, nous étudions certains points techniques clé sur ce sujet et proposons une résolution pratique et efficace des aspects suivants: Dans un cadre de design inter-couche, nous avons d'abord réglé le problème du contrôle de débit et du routage. Nous étudions la combinaison de l'acheminement et le contrôle du taux avec une formulation optimisation convexe afin de proposer une solution distribuée commune basée sur la conception des inter-couche. Nous avons d'abord développé un modèle de distorsion qui couvre à la fois l'impact de la quantification du codeur et la perte de paquets en raison de la congestion du réseau sur la qualité vidéo globale. Ensuite, le contrôle du taux d'émission optimal commun et le choix du routage sont réalisés en adaptant la vitesse variable d'émission au cours du temps et en minimisant la congestion du réseau global. Ensuite, nous abordons le problème du mécanisme d'authentification du codage conjoint. Dans cette partie, nous proposons un cadre pour une collaboration entre authentification et codage multimédia transmis sur des réseaux sans fil. Premièrement, nous fournissons un système d'authentification basé sur des méthodes graphiques qui peut non seulement construire une authentification flexible, mais aussi un compromis parmi certaines exigences pratiques telles que la robustesse et le retard. Puis, un taux de distorsion conjoint Source-Canal (JSCC) est optimisé ; une approche résistante aux erreurs vidéo encodée adpatative est présentée, dans laquelle la vidéo est encodée en plusieurs flux indépendants et à chaque flux est attribué une correction (Forward Error Correction-FEC) afin d'éviter la propagation des erreurs. En outre, nous considérons l'authentification avec le régime spécifique JSCC afin de parvenir à un résultat satisfaisant en termes de qualité de reconstruction de bout en bout. Ensuite, nous proposons d'appliquer conjointement la résilience aux erreurs (ER) et la super-résolution (SR) afin d'améliorer glabalement la résolution des flux d'images transmises sur les réseaux sans fil. Afin de lutter contre la propagation d'erreurs, une description multiple, méthode flexible de codage basée sur SPIHT-3-D (partitionnement 3-D dans des arbres hiérarchiques) est présentée pour générer des descriptions variables indépendantes en fonction de l'état du réseau. Puis, une stratégie originale de protection inégale contre les erreurs suivant le niveau de priorité est prévu afin d'attribuer un niveau supérieur de protection contre les erreurs des parties les plus importantes des flux. En outre, un algorithme robuste SR est proposé, en présence de différents types de taux de perte de paquets pour améliorer la résolution de l'image. Enfin, nous décrivons le problème du contrôle du taux pour le multimédia sur des réseaux hétérogènes. Dans cette partie, nous développons et évaluons un cadre d'allocation des taux optimaux sur plusieurs réseaux hétérogènes toujours basés sur le cadre de la conception inter-couches. Au début, nous développons et évaluons un modèle de distorsion en fonction de taux disponibles observés (ABR) et du temps d'aller-retour (RTT) dans chaque réseau d'accès, ainsi que des caractéristiques de chaque application. Ensuite, la répartition du taux est formulée comme un problème d'optimisation convexe qui minimise la somme de la distorsion attendue sur tous les flux applicatifs. Afin d'obtenir une résolution satisfaisante et simple à ce problème, nous proposons un théorème d'approximation par morceaux afin de simplifier le problème convexe et de prouver la validité de la théorie. En outre, la réalisation de l'algorithme rapide heuristique pour parvenir à une répartition optimale de qualité de service ou quasi-optimale de bout en bout dans le cadre du budget global des ressources limitées est le point le plus important de cette partie de thèse. En fin de compte, un bref résumé de tous les sujets abordés dans cette thèse est donné. Les principales contributions de cette thèse sont alors rappelés.
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Vio, Renato Peres. "Improved uuv positioning using acoustic communications and a potential for real-time networking and collaboration/Renato Peres Vio." reponame:Repositório Institucional da Diretoria do Patrimônio Histórico e Documentação da Marinha, 2017. http://repositorio.mar.mil.br/handle/ripcmb/26340.
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Tese (Doutorado) - Naval Postgraduate Scholl, Monterey, CA, 2017.Devido a falta de auxílios na navegação subaquática, um sistema capaz de ajudar um veículo submersível a manter a precisão da posição, permitindo que ele permaneça subaquático por períodos mais longos, é extremamente desejável. A precisão e confiabilidade
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Rieser, Christian James. "Biologically Inspired Cognitive Radio Engine Model Utilizing Distributed Genetic Algorithms for Secure and Robust Wireless Communications and Networking." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/11283.
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This research focuses on developing a cognitive radio that could operate reliably in unforeseen communications environments like those faced by the disaster and emergency response communities. Cognitive radios may also offer the potential to open up secondary or complimentary spectrum markets, effectively easing the perceived spectrum crunch while providing new competitive wireless services to the consumer. A structure and process for embedding cognition in a radio is presented, including discussion of how the mechanism was derived from the human learning process and mapped to a mathematical formalism called the BioCR. Results from the implementation and testing of the model in a hardware test bed and simulation test bench are presented, with a focus on rapidly deployable disaster communications. Research contributions include developing a biologically inspired model of cognition in a radio architecture, proposing that genetic algorithm operations could be used to realize this model, developing an algorithmic framework to realize the cognition mechanism, developing a cognitive radio simulation toolset for evaluating the behavior the cognitive engine, and using this toolset to analyze the cognitive engineà Âs performance in different operational scenarios. Specifically, this research proposes and details how the chaotic meta-knowledge search, optimization, and machine learning properties of distributed genetic algorithm operations could be used to map this model to a computable mathematical framework in conjunction with dynamic multi-stage distributed memories. The system formalism is contrasted with existing cognitive radio approaches, including traditionally brittle artificial intelligence approaches. The cognitive engine architecture and algorithmic framework is developed and introduced, including the Wireless Channel Genetic Algorithm (WCGA), Wireless System Genetic Algorithm (WSGA), and Cognitive System Monitor (CSM). Experimental results show that the cognitive engine finds the best tradeoff between a host radio's operational parameters in changing wireless conditions, while the baseline adaptive controller only increases or decreases its data rate based on a threshold, often wasting usable bandwidth or excess power when it is not needed due its inability to learn. Limitations of this approach include some situations where the engine did not respond properly due to sensitivity in algorithm parameters, exhibiting ghosting of answers, bouncing back and forth between solutions. Future research could be pursued to probe the limits of the engineà Âs operation and investigate opportunities for improvement, including how best to configure the genetic algorithms and engine mathematics to avoid engine solution errors. Future research also could include extending the cognitive engine to a cognitive radio network and investigating implications for secure communications.Ph. D.
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Sato, Ken-ichi, and Hiroshi Hasegawa. "Optical Networking Technologies That Will Create Future Bandwidth-Abundant Networks [Invited]." IEEE, 2009. http://hdl.handle.net/2237/13919.
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Ginzburg, Ilan. "Athapascan-0b : intégration efficace et portable de multiprogrammation légère et de communications." Phd thesis, Grenoble INPG, 1997. http://tel.archives-ouvertes.fr/tel-00004946.
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Athapascan-0b est un noyau exécutif pour machines parallèles supportant la multiprogrammation légère. Athapascan-0b permet un développement portable d'applications parallèles irrégulières et une exécution efficace de celles-ci sur un grand nombre de plates-formes. Ce document commence par la présentation du cadre dans lequel s'inscrit Athapascan-0b, à savoir les communications, la multiprogrammation légère et l'intégration de ces deux fonctionnalités. Sont ensuite présentes les concepts structurant Athapascan-0b ainsi que son interface de programmation. La problématique d'une intégration de communications et de multiprogrammation légère est posée, la réalisation d'Athapascan-0b est décrite et plus précisement le choix d'implantation, à savoir un mariage de bibliothèques existantes de multiprogrammation légère et de communications. Enfin, la performance d'Athapascan-0b est evaluée, comparée à la performance des bibliothèques au dessus desquelles il a été développé. L'exécution de quelques exemples est analysée afin de mieux comprendre les mécanismes en jeu.
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Ascigil, Mehmet O. "Design of a Scalable Path Service for the Internet." UKnowledge, 2015. http://uknowledge.uky.edu/cs_etds/29.
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Despite the world-changing success of the Internet, shortcomings in its routing and forwarding system have become increasingly apparent. One symptom is an escalating tension between users and providers over the control of routing and forwarding of packets: providers understandably want to control use of their infrastructure, and users understandably want paths with sufficient quality-of-service (QoS) to improve the performance of their applications. As a result, users resort to various “hacks” such as sending traffic through intermediate end-systems, and the providers fight back with mechanisms to inspect and block such traffic.
To enable users and providers to jointly control routing and forwarding policies, recent research has considered various architectural approaches in which provider- level route determination occurs separately from forwarding. With this separation, provider-level path computation and selection can be provided as a centralized service: users (or their applications) send path queries to a path service to obtain provider- level paths that meet their application-specific QoS requirements. At the same time, providers can control the use of their infrastructure by dictating how packets are forwarded across their network. The separation of routing and forwarding offers many advantages, but also brings a number of challenges such as scalability. In particular, the path service must respond to path queries in a timely manner and periodically collect topology information containing load-dependent (i.e., performance) routing information.
We present a new design for a path service that makes use of expensive pre- computations, parallel on-demand computations on performance information, and caching of recently computed paths to achieve scalability. We demonstrate that, us- ing commodity hardware with a modest amount of resources, the path service can respond to path queries with acceptable latency under a realistic workload. The ser- vice can scale to arbitrarily large topologies through parallelism. Finally, we describe how to utilize the path service in the current Internet with existing Internet applica- tions.
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Calabrigo, Adam Chase. "SD-MCAN: A Software-Defined Solution for IP Mobility in Campus Area Networks." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1797.
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Campus Area Networks (CANs) are a subset of enterprise networks, comprised of a network core connecting multiple Local Area Networks (LANs) across a college campus. Traditionally, hosts connect to the CAN via a single point of attachment; however, the past decade has seen the employment of mobile computing rise dramatically. Mobile devices must obtain new Internet Protocol (IP) addresses at each LAN as they migrate, wasting address space and disrupting host services. To prevent these issues, modern CANs should support IP mobility: allowing devices to keep a single IP address as they migrate between LANs with low-latency handoffs. Traditional approaches to mobility may be difficult to deploy and often lead to inefficient routing, but Software-Defined Networking (SDN) provides an intriguing alternative. This thesis identifies necessary requirements for a software-defined IP mobility system and then proposes one such system, the Software-Defined Mobile Campus Area Network (SD-MCAN) architecture. SD-MCAN employs an OpenFlow-based hybrid, label-switched routing scheme to efficiently route traffic flows between mobile hosts on the CAN. The proposed architecture is then implemented as an application on the existing POX controller and evaluated on virtual and hardware testbeds. Experimental results show that SD-MCAN can process handoffs with less than 90 ms latency, suggesting that the system can support data-intensive services on mobile host devices. Finally, the POX prototype is open-sourced to aid in future research.
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Plewtong, Nicholas. "Modeling Adversarial Insider Vehicles in Mix Zones." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1810.
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Security is a necessity when dealing with new forms of technology that may not have been analyzed from a security perspective. One of the latest growing technological advances are Vehicular Ad-Hoc Networks (VANETs). VANETs allow vehicles to communicate information to each other wirelessly which allows for an increase in safety and efficiency for vehicles. However, with this new type of computerized system comes the need to maintain security on top of it.
In order to try to protect location privacy of the vehicles in the system, vehicles change pseudonyms or identifiers at areas known as mix zones. This thesis implements a model that characterizes the attack surface of an adversarial insider vehicle inside of a VANET. This adversarial vehicle model describes the interactions and effects that an attacker vehicle can have on mix zones in order to lower the overall location privacy of the system and remain undetected to defenders in the network. In order to reach the final simulation of the model, several underlying models had to be developed around the interactions of defender and attacker vehicles.
The evaluation of this model shows that there are significant impacts that internal attacker vehicles can have on location privacy within mix zones. From the created simulations, the results show that having one to five optimal attackers shows a decrease of 0.6%-2.6% on the location privacy of the network and a 12% decrease in potential location privacy in a mix zone where an attacker defects in a 50-node network. The industry needs to consider implementing defenses based on this particular attack surface discussed.