201 research outputs found
Proceedings Work-In-Progress Session of the 13th Real-Time and Embedded Technology and Applications Symposium
The Work-In-Progress session of the 13th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS\u2707) presents papers describing contributions both to state of the art and state of the practice in the broad field of real-time and embedded systems. The 17 accepted papers were selected from 19 submissions. This proceedings is also available as Washington University in St. Louis Technical Report WUCSE-2007-17, at http://www.cse.seas.wustl.edu/Research/FileDownload.asp?733. Special thanks go to the General Chairs â Steve Goddard and Steve Liu and Program Chairs - Scott Brandt and Frank Mueller for their support and guidance
Recent Trends in Communication Networks
In recent years there has been many developments in communication technology. This has greatly enhanced the computing power of small handheld resource-constrained mobile devices. Different generations of communication technology have evolved. This had led to new research for communication of large volumes of data in different transmission media and the design of different communication protocols. Another direction of research concerns the secure and error-free communication between the sender and receiver despite the risk of the presence of an eavesdropper. For the communication requirement of a huge amount of multimedia streaming data, a lot of research has been carried out in the design of proper overlay networks. The book addresses new research techniques that have evolved to handle these challenges
Emerging Communications for Wireless Sensor Networks
Wireless sensor networks are deployed in a rapidly increasing number of arenas, with uses ranging from healthcare monitoring to industrial and environmental safety, as well as new ubiquitous computing devices that are becoming ever more pervasive in our interconnected society. This book presents a range of exciting developments in software communication technologies including some novel applications, such as in high altitude systems, ground heat exchangers and body sensor networks. Authors from leading institutions on four continents present their latest findings in the spirit of exchanging information and stimulating discussion in the WSN community worldwide
Performance evaluation of Vehicular Ad Hoc Networks over high speed environment using NCTUns
CatalĂ : Cada any aproximadament un miliĂł dues-centes mil persones moren en accidents de trĂ nsit. D'aquesta dada es desprĂšn que els accidents de trĂ nsit sĂłn la quarta causa de mortalitat al mĂłn. Degut a aixĂČ, un gran nombre de governs i els majors fabricants de vehicles del mĂłn estan invertint temps i diners en recerca i desenvolupament per millorar la seguretat a les carreteres. Amb aquest objectiu, apareix el concepte de VANET: Vehicular Ad-hoc NETwork. Una VANET estĂ basada en vehicles i estacions base intel·ligents que comparteixen informaciĂł a travĂ©s de comunicacions inalĂ mbriques. Aquest intercanvi de dades podria tenir un gran impacte en la seguretat viĂ ria i la qualitat en la conducciĂł perĂČ a mĂ©s a mĂ©s seria una nova font d' entreteniment mĂČbil. La millora en seguretat implicaria una reducciĂł en el nombre d'accidents i les comunicacions inalĂ mbriques usades en mobilitat permetrien una optimitzaciĂł del transport. L'evoluciĂł de les VANETs en els Ășltims anys i les seves aplicacions Ăștils a les carreteres sĂłn les principals raons per dur a terme aquest projecte. El gran suport a aquest tipus de xarxes inalĂ mbriques sembla indicar que les VANETs sĂłn les xarxes del futur en entorns mĂČbils. En relaciĂł al projecte, el primer problema observat Ă©s que el protocol que s'usa especĂficament en VANETs (802.11p) nomĂ©s estĂ disponible en pocs simuladors de xarxa i estĂ en fase de desenvolupament. Per tant, la majoria de les funcions no estan implementades i aixĂČ fa que el protocol no sigui madur. En conseqĂŒĂšncia, es va triar un protocol Ă mpliament usat com Ă©s 802.11b per fer les proves en el simulador NCTUns. L?objectiu del projecte Ă©s avaluar el funcionament de VANETs usant el protocol 802.11b i el protocol d?encaminament AODV en un escenari d?autopista. Ajustant diferents parĂ metres com el nombre de cotxes, la seva velocitat i el seu rang de cobertura Ă©s possible obtenir variacions en les mesures de pĂšrdues, throughput i retard extrem-a-extrem en la xarxa. El resultat final Ă©s que les mesures permeten saber quines sĂłn les comunicacions que es produeixen a la xarxa per cadascuna de les configuracions i la seva incidĂšncia en les condicions de conducciĂł.Castellano: Cada año cerca de un millĂłn doscientas mil personas fallecen en accidentes de trĂĄfico. De este dato se desprende que los accidentes de trĂĄfico son la cuarta causa de mortalidad en el mundo. Debido a esto, un gran nĂșmero de gobiernos y los mayores fabricantes de vehĂculos del mundo estĂĄn invirtiendo tiempo y dinero en investigaciĂłn y desarrollo para mejorar la seguridad en las carreteras. Con este objetivo, aparece el concepto de VANET: Vehicular Ad-hoc NETwork. Una VANET se basa en vehĂculos y estaciones base inteligentes que comparten informaciĂłn por medio de comunicaciones inalĂĄmbricas. Este intercambio de datos podrĂa tener un gran impacto en la seguridad vial y en la calidad de la conducciĂłn pero ademĂĄs serĂa una nueva fuente de entretenimiento mĂłvil. La mejora en la seguridad implicarĂa una reducciĂłn en el nĂșmero de accidentes y las comunicaciones inalĂĄmbricas utilizadas en movilidad permitirĂan optimizar el transporte. La evoluciĂłn de las VANETs en los Ășltimos años y sus aplicaciones Ăștiles en las carreteras son las principales razones para llevar a cabo este proyecto. El gran apoyo a este tipo de redes inalĂĄmbricas parece indicar que las VANETs son las redes del futuro en entornos mĂłviles. En relaciĂłn al proyecto, el primer problema observado es que el protocolo especĂficamente utilizado en VANETs (802.11p) sĂłlo estĂĄ disponible en pocos simuladores de red y se encuentra en fase de desarrollo. Por lo tanto, la mayorĂa de funciones no estĂĄn implementadas y esto hace que el protocolo no sea maduro. En consecuencia, se escogiĂł un protocolo ampliamente utilizado como es 802.11b para realizar las pruebas en el simulador NCTUns. El objetivo del proyecto es evaluar el funcionamiento de VANETs utilizando el protocolo 802.11b y el protocolo de encaminamiento AODV en un escenario de autopista. Ajustando diferentes parĂĄmetros como el nĂșmero de coches, su velocidad y su rango de cobertura es posible obtener variaciones en las medidas de pĂ©rdidas, throughput y retardo extremo-a-extremo en la red. El resultado final es que las medidas permiten saber cuĂĄles son las comunicaciones que se producen en la red para cada una de las configuraciones y su incidencia en las condiciones de conducciĂłn.English: Every year about 1.2 million people die because of traffic accidents [1]. This means that traffic accidents are the fourth cause of mortality in the world. Therefore, several governments and the most important car manufacturers are investing time and money on research and development in order to improve road safety. At this respect, appears the concept of VANET: Vehicular Ad-hoc NETwork. A VANET is based on smart cars and base-stations that share information via wireless communications. This interchange of data may have a great impact on safety and driving quality but also could be another source of mobile entertainment. This improvement on safety would imply reducing the number of accidents. In addition, the use of wireless communications in mobility would lead to an optimization of transport. The evolution of VANETs in the last years and their useful applications on the road has been the main reason to develop this project. The great support of many people to this type of wireless networks suggests that VANETs are the networks of the future in mobile environments. Regarding the project, the first problem encountered is that the network protocol specially designed for VANETs, IEEE 802.11p, is only available in a few of the network simulators and is on phase of development. This fact means that most of the functions are not implemented so it cannot be considered as a mature protocol. As a consequence, a widely used protocol as IEEE 802.11b was chosen and all the tests were performed on NCTUns simulator. So the purpose of this project is to evaluate the performance of VANETs by using 802.11b protocol and AODV routing protocol in a highway scenario. By adjusting different parameters like number of cars, their speed and their range of coverage, variations on measures of loss ratio, throughput and end-to- end delay were detected on the network. Finally, the measures help to know about network communications for each of the cases and their incidence on driving conditions
Biologically inspired, self organizing communication networks.
PhDThe problem of energy-efficient, reliable, accurate and self-organized target tracking in
Wireless Sensor Networks (WSNs) is considered for sensor nodes with limited physical
resources and abrupt manoeuvring mobile targets. A biologically inspired, adaptive
multi-sensor scheme is proposed for collaborative Single Target Tracking (STT) and
Multi-Target Tracking (MTT). Behavioural data obtained while tracking the targets
including the targetsâ previous locations is recorded as metadata to compute the target
sampling interval, target importance and local monitoring interval so that tracking
continuity and energy-efficiency are improved. The subsequent sensor groups that track
the targets are selected proactively according to the information associated with the
predicted target location probability such that the overall tracking performance is
optimized or nearly-optimized. One sensor node from each of the selected groups is
elected as a main node for management operations so that energy efficiency and load
balancing are improved. A decision algorithm is proposed to allow the âconflictâ nodes
that are located in the sensing areas of more than one target at the same time to decide
their preferred target according to the target importance and the distance to the target. A
tracking recovery mechanism is developed to provide the tracking reliability in the
event of target loss.
The problem of task mapping and scheduling in WSNs is also considered. A
Biological Independent Task Allocation (BITA) algorithm and a Biological Task
Mapping and Scheduling (BTMS) algorithm are developed to execute an application
using a group of sensor nodes. BITA, BTMS and the functional specialization of the
sensor groups in target tracking are all inspired from biological behaviours of
differentiation in zygote formation.
Simulation results show that compared with other well-known schemes, the
proposed tracking, task mapping and scheduling schemes can provide a significant
improvement in energy-efficiency and computational time, whilst maintaining
acceptable accuracy and seamless tracking, even with abrupt manoeuvring targets.Queen Mary university of London full Scholarshi
A framework for evaluating countermeasures against sybil attacks in wireless sensor networks
Although Wireless Sensor Networks (WSNs) have found a niche in numerous applications, they are constrained by numerous factors. One of these important factors is security in WSNs. There are various types of security attacks that WSNs are susceptible to. The focus of this study is centred on Sybil attacks, a denial of service attack. In this type of attack, rogue nodes impersonate valid nodes by falsely claiming to possess authentic identities, thereby rendering numerous core WSN operations ineffective. The diverse nature of existing solutions poses a difficult problem for system engineers wanting to employ a best fit countermeasure. This problem is the largely unanswered question posed to all system engineers and developers alike whose goal is to design/develop a secure WSN. Resolving this dilemma proves to be quite a fascinating task, since there are numerous factors to consider and more especially one cannot assume that every application is affected by all identified factors. A framework methodology presented in this study addresses the abovementioned challenges by evaluating countermeasure effectiveness based on theoretical and practical security factors. Furthermore, a process is outlined to determine the applicationâs engineering requirements and the framework also suggests what security components the system engineer ought to incorporate into the application, depending on the applicationâs risk profile. The framework then numerically aligns these considerations, ensuring an accurate and fairly unbiased best fit countermeasure selection. Although the framework concentrates on Sybil countermeasures, the methodology can be applied to other classes of countermeasures since it answers the question of how to objectively study and compare security mechanisms that are both diverse and intended for different application environments. The report documents the design and development of a comparative framework that can be used to evaluate countermeasures against Sybil attacks in wireless sensor networks based on various criteria that will be discussed in detail. This report looks briefly at the aims and description of the research. Following this, a literature survey on the body of knowledge concerning WSN security and a discussion on the proposed methodology of a specific design approach are given. Assumptions and a short list of factors that were considered are then described. Metrics, the taxonomy for WSN countermeasures, the framework and a formal model are developed. Risk analysis and the best fit methodology are also discussed. Finally, the results and recommendations are shown for the research, after which the document is concluded.Dissertation (MEng)--University of Pretoria, 2011.Electrical, Electronic and Computer Engineeringunrestricte
Decentralized data fusion and data harvesting framework for heterogeneous dynamic network systems
ï»żDiese Dissertation behandelt das Thema der dezentralisieren Sammlung und
Fusion von Daten in heterogenen, ressourcenbeschraekten und dynamischen
Netzwerkszenarien.
Dazu wird ein generisches Framework vorgestellt, dass
es erlaubt die Datensammlung, den Datenaustausch und auch die Datenfusion
dynamisch zu konfigurieren. Im Zuge dessen wird auch eine Methode zur
gerichteten Fusion von Daten auf graphentheoretischer Basis eingefrt, die
es erlaubt eine logische Struktur fuer die Fusion von Informationen zu
modellieren. Eine Markup-Sprache, die sowohl menschen- als auch
maschinenlesbar ist, erlaubt es diese Struktur leicht zu editieren.
Im
Bereich der Protokolle zum Datenaustausch liegt der Fokus dieser Arbeit auf
Energieeffizienz, um auch ressourcenbeschraenkte Geraete einzubinden. Ein
weiterer Schwerpunkt liegt auf Robustheit fuer die betrachteten dynamischen
Szenarien.
Diese Dissertation schlaet zudem Design-Richtlinien vor, um
verschiedene Ziele fuer unterschiedliche Applikationen umzusetzen. Diese
lassen sich leicht in das vorgestellte Framework integrieren und darueber
konfigurieren. Dadurch ergibt sich im Ganzen eine flexible Architektur, die
sich leicht an dynamische Umgebungen anpassen laesst.With the increasing number of available smart phones, sensor nodes, and
novel mobile smart devices such as Google glass, a large volume of data
reflecting the environment is generated in the form of sensing data sources
(such as GPS, received signal strength identification, accelerometer,
microphone, images, videos and gyroscope, etc.). Some context-aware and
data centric applications require the online processing of the data
collected. The thesis researches on the decentralized data fusion and data
harvesting framework for heterogeneous dynamic network system consisting of
various devices with resource constraints. In order to achieve the flexible
design, a general architecture is provided while the detailed data fusion
and data exchange functions can be dynamically configured. A novel method
to use directed fusion graph to model the logical structure of the
distributed information fusion architecture is introduced. This directed
fusion graph can accurately portray the interconnection among different
data fusion components and the data exchange protocols, as well as the
detailed data streams. The directed fusion graph is then transformed into a
format with marked language, so that both human and machine can easily
understand and edit. In the field of data exchange protocols, this thesis
targets energy-efficiency considering the resource constraints of the
devices and robustness, as the dynamic environment might cause failures to
the system. It proposes a refined gossip strategy to reduce retransmission
of redundant data. The thesis also suggests a design guideline to achieve
different design aims for different applications. These results in this
field can be integrated into the framework effortlessly. The configuration
mechanism is another feature of this framework. Different from other
research work which consider configuration as a post-design work separated
from the main design of any middle-ware. This thesis considers the
configuration part as another dimension of the framework. The whole
strategy in configuration sets up the foundation for the flexible
architecture, and makes it easy to adapt to the dynamic environment. The
contributions in the above fields lead to a light-weight data fusion and
data harvesting framework which can be deployed easily above wireless
based, heterogeneous, dynamic network systems, even in extreme conditions,
to handle data-centric applications
Radio Communications
In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modiïŹed our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the ïŹeld of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks
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