Analysis of the OLSR Protocol by Using Formal Passive Testing

In this paper we apply a passive testing methodology to the analysis of a non-trivial system. In our framework, so-called invariants provide us with a formal representation of the requirements of the system. In order to precisely express new properties in multi-node environments, in this paper we introduce a new kind of invariants. We apply the resulting framework to perform a complete study of a MANET routing protocol: The Optimized Link State Routing protocol

Yet Another Autoconf Proposal (YAAP) for Mobile Ad hoc NETworks

This memorandum addresses the issues of automatic address and prefix configuration of MANET routers. Specifically, the paper analyzes the differences between "classic IP networks" and MANETs, emphasizing the interface, link, topology, and addressing assumptions present in "classic IP networks". The paper presents a model for how this can be matched to the specific constraints and conditions of a MANET - i.e., how MANETs can be configured to adhere to the Internet addressing architecture. This sets the stage for development of a MANET autoconfiguration protocol, enabling automatic configuration of MANET interfaces and prefix delegation. This autoconfiguration protocol is characterized by (i) adhering strictly to the Internet addressing architecture, (ii) being able to configure both MANET interface addresses and handle prefix delegation, and (iii) being able to configure both stand-alone MANETs, as well as MANETs connected to an infrastructure providing, e.g., globally scoped addresses/prefixes for use within the MANET. The protocol is specified through timed automatons which, by way of model checking, enable verification of certain protocol properties. Furthermore, a performance study of the basic protocol, as well as of various optimization and extensions hereto, is conducted based on network simulations.Cet article aborde les questions liées à la configuration automatique des adresses et préfixes dans les routeurs MANET. Plus spécifiquement, il analyse les différences entre les « réseaux IP classiques » et les réseaux MANET, en mettant l'accent sur l'interface, les liens et la topologie. Il étudie les hypothèses sous-jacentes dans les réseaux IP classiques et présente un modèle satisfaisant ces hypothèses dans le contexte spécifique des contraintes et conditions d'un réseau MANET, permettant par exemple de configurer les réseaux MANET de sortent qu'ils adhèrent à l'architecture d'adressage d'Internet. Les bases sont ainsi posées pour le développement d'un protocole d'auto configuration MANET, permettant la configuration automatique des interfaces MANET et la délégation automatique de préfixes. Ce protocole de configuration automatique se caractérise (i) par son adhérence stricte à l'architecture d'adressage d'Internet, (ii) par sa double capacité de configuration des interfaces MANET et de délégation de préfixes, et enfin (iii) par son aptitude à configurer aussi bien des réseaux MANETS indépendants que des réseaux MANET connectés à une infrastructure fournissant par exemple des adresses et préfixes à portée globale pour leur utilisation dans MANET. Le protocole est défini au travers d'automates temporels, qui grâce à un modèle de contrôle, permettent de vérifier certaines propriétés du protocole. En outre, une étude des performances du protocole de base, ainsi que de diverses optimisations et extensions, a été conduite à partir de simulations de réseau

Investigating TCP performance in mobile ad hoc networks

Mobile ad hoc networks (MANETs) have become increasingly important in view of their promise of ubiquitous connectivity beyond traditional fixed infrastructure networks. Such networks, consisting of potentially highly mobile nodes, have provided new challenges by introducing special consideration stemming from the unique characteristics of the wireless medium and the dynamic nature of the network topology. The TCP protocol, which has been widely deployed on a multitude of internetworks including the Internet, is naturally viewed as the de facto reliable transport protocol for use in MANETs. However, assumptions made at TCP’s inception reflected characteristics of the prevalent wired infrastructure of networks at the time and could subsequently lead to sub-optimal performance when used in wireless ad hoc environments. The basic presupposition underlying TCP congestion control is that packet losses are predominantly an indication of congestion in the network. The detrimental effect of such an assumption on TCP’s performance in MANET environments has been a long-standing research problem. Hence, previous work has focused on addressing the ambiguity behind the cause of packet loss as perceived by TCP by proposing changes at various levels across the network protocol stack, such as at the MAC mechanism of the transceiver or via coupling with the routing protocol at the network layer. The main challenge addressed by the current work is to propose new methods to ameliorate the illness-effects of TCP’s misinterpretation of the causes of packet loss in MANETs. An assumed restriction on any proposed modifications is that resulting performance increases should be achievable by introducing limited changes confined to the transport layer. Such a restriction aids incremental adoption and ease of deployment by requiring minimal implementation effort. Further, the issue of packet loss ambiguity, from a transport layer perspective, has, by definition, to be dealt with in an end-to-end fashion. As such, a proposed solution may involve implementation at the sender, the receiver or both to address TCP shortcomings. Some attempts at describing TCP behaviour in MANETs have been previously reported in the literature. However, a thorough enquiry into the performance of those TCP agents popular in terms of research and adoption has been lacking. Specifically, very little work has been performed on an exhaustive analysis of TCP variants across different MANET routing protocols and under various mobility conditions. The first part of the dissertation addresses this shortcoming through extensive simulation evaluation in order to ascertain the relative performance merits of each TCP variant in terms of achieved goodput over dynamic topologies. Careful examination reveals sub-par performance of TCP Reno, the largely equivalent performance of NewReno and SACK, whilst the effectiveness of a proactive TCP variant (Vegas) is explicitly stated and justified for the first time in a dynamic MANET environment. Examination of the literature reveals that in addition to losses caused by route breakages, the hidden terminal effect contributes significantly to non-congestion induced packet losses in MANETs, which in turn has noticeably negative impact on TCP goodput. By adapting the conservative slow start mechanism of TCP Vegas into a form suitable for reactive TCP agents, like Reno, NewReno and SACK, the second part of the dissertation proposes a new Reno-based congestion avoidance mechanism which increases TCP goodput considerably across long paths by mitigating the negative effects of hidden terminals and alleviating some of the ambiguity of non-congestion related packet loss in MANETs. The proposed changes maintain intact the end-to-end semantics of TCP and are solely applicable to the sender. The new mechanism is further contrasted with an existing transport layer-focused solution and is shown to perform significantly better in a range of dynamic scenarios. As solution from an end-to-end perspective may be applicable to either or both communicating ends, the idea of implementing receiver-side alterations is also explored. Previous work has been primarily concerned with reducing receiver-generated cumulative ACK responses by “bundling” them into as few packets as possible thereby reducing misinterpretations of packet loss due to hidden terminals. However, a thorough evaluation of such receiver-side solutions reveals limitations in common evaluation practices and the solutions themselves. In an effort to address this shortcoming, the third part of this research work first specifies a tighter problem domain, identifying the circumstances under which the problem may be tackled by an end-to-end solution. Subsequent original analysis reveals that by taking into account optimisations possible in wireless communications, namely the partial or complete omission of the RTS/CTS handshake, noticeable improvements in TCP goodput are achievable especially over long paths. This novel modification is activated in a variety of topologies and is assessed using new metrics to more accurately gauge its effectiveness in a wireless multihop environment

A novel anomaly behavior detection scheme for mobile ad hoc networks

To sustain the security services in a Mobile Ad Hoc Networks (MANET), applications in terms of confidentially, authentication, integrity, authorization, key management, and abnormal behavior detection/anomaly detection are significant. The implementation of a sophisticated security mechanism requires a large number of network resources that degrade network performance. In addition, routing protocols designed for MANETs should be energy efficient in order to maximize network performance. In line with this view, this work proposes a new hybrid method called the data-driven zone-based routing protocol (DD-ZRP) for resource-constrained MANETs that incorporate anomaly detection schemes for security and energy awareness using Network Simulator 3. Most of the existing schemes use constant threshold values, which leads to false positive issues in the network. DD-ZRP uses a dynamic threshold to detect anomalies in MANETs. The simulation results show an improved detection ratio and performance for DD-ZRP over existing schemes; the method is substantially better than the prevailing protocols with respect to anomaly detection for security enhancement, energy efficiency, and optimization of available resources

An approach to pervasive monitoring in dynamic learning contexts : data sensing, communication support and awareness provision

It is within the capabilities of current technology to support the emerging learning paradigms. These paradigms suggest that today’s learning activities and environments are pervas ive and require a higher level of dynamism than the traditional learning contexts. Therefore, we have to rethink our approach to learning and use technology not only as a digital information support, but also as an instrument to reinforce knowledge, foster collaboration, promote creativity and provide richer learning experiences. Particularly, this thesis was motivated by the rapidly growing number of smartphone users and the fact that these devices are increasingly becoming more and more resource-rich, in terms of their communication and sensing technologies, display capabilities battery autonomy, etc. Hence, this dissertation benefits from the ubiquity and development of mobile technology, aiming to bridge the gap between the challenges posed by modern learning requirements and the capabilities of current technology. The sensors embedded in smartphones can be used to capture diverse behavioural and social aspects of the users. For example, using microphone and Bluetooth is possible to identify conversation patterns, discover users in proximity and detect face-to-face meetings. This fact opens up exciting possibilities to monitor the behaviour of the user and to provide meaningful feedback. This feedback offers useful information that can help people be aware of and reflect on their behaviour and its effects, and take the necessary actions to improve them. Consequently, we propose a pervasive monitoring system that take advantage of the capabilities of modern smartphones, us ing them to s upport the awarenes s provis ion about as pects of the activities that take place in today’s pervas ive learning environments. This pervasive monitoring system provides (i) an autonomous sensing platform to capture complex information about processes and interactions that take place across multiple learning environments, (ii) an on-demand and s elf-m anaged communication infras tructure, and (ii) a dis play facility to provide “awarenes s inform ation” to the s tudents and/or lecturers. For the proposed system, we followed a research approach that have three main components. First, the description of a generalized framework for pervasive sensing that enables collaborative sensing interactions between smartphones and other types of devices. By allowing complex data capture interactions with diverse remote sensors, devices and data sources, this framework allows to improve the information quality while saving energy in the local device. Second, the evaluation, through a real-world deployment, of the suitability of ad hoc networks to support the diverse communication processes required for pervasive monitoring. This component also includes a method to improve the scalability and reduce the costs of these networks. Third, the design of two awareness mechanisms to allow flexible provision of information in dynamic and heterogeneous learning contexts. These mechanisms rely on the use of smartphones as adaptable devices that can be used directly as awareness displays or as communication bridges to enable interaction with other remote displays available in the environment. Diverse aspects of the proposed system were evaluated through a number of simulations, real-world experiments, user studies and prototype evaluations. The experimental evaluation of the data capture and communication aspects of the system provided empirical evidence of the usefulness and suitability of the proposed approach to support the development of pervasive monitoring solutions. In addition, the proof-of-concept deployments of the proposed awareness mechanisms, performed in both laboratory and real-world learning environments, provided quantitative and qualitative indicators that such mechanisms improve the quality of the awareness information and the user experienceLa tecnología moderna tiene capacidad de dar apoyo a los paradigmas de aprendizaje emergentes. Estos paradigmas sugieren que las actividades de aprendizaje actuales, caracterizadas por la ubicuidad de entornos, son más dinámicas y complejas que los contextos de aprendizaje tradicionales. Por tanto, tenemos que reformular nuestro acercamiento al aprendizaje, consiguiendo que la tecnología sirva no solo como mero soporte de información, sino como medio para reforzar el conocimiento, fomentar la colaboración, estimular la creatividad y proporcionar experiencias de aprendizaje enriquecedoras. Esta tesis doctoral está motivada por el vertiginoso crecimiento de usuarios de smartphones y el hecho de que estos son cada vez más potentes en cuanto a tecnologías de comunicación, sensores, displays, autonomía energética, etc. Por tanto, esta tesis aprovecha la ubicuidad y el desarrollo de esta tecnología, con el objetivo de reducir la brecha entre los desafíos del aprendizaje moderno y las capacidades de la tecnología actual. Los sensores integrados en los smartphones pueden ser utilizados para reconocer diversos aspectos del comportamiento individual y social de los usuarios. Por ejemplo, a través del micrófono y el Bluetooth, es posible determinar patrones de conversación, encontrar usuarios cercanos y detectar reuniones presenciales. Este hecho abre un interesante abanico de posibilidades, pudiendo monitorizar aspectos del comportamiento del usuario y proveer un feedback significativo. Dicho feedback, puede ayudar a los usuarios a reflexionar sobre su comportamiento y los efectos que provoca, con el fin de tomar medidas necesarias para mejorarlo. Proponemos un sistema de monitorización generalizado que aproveche las capacidades de los smartphones para proporcionar información a los usuarios, ayudándolos a percibir y tomar conciencia sobre diversos aspectos de las actividades que se desarrollan en contextos de aprendizaje modernos. Este sistema ofrece: (i) una plataforma de detección autónoma, que captura información compleja sobre los procesos e interacciones de aprendizaje; (ii) una infraestructura de comunicación autogestionable y; (iii) un servicio de visualización que provee “información de percepción” a estudiantes y/o profesores. Para la elaboración de este sistema nos hemos centrado en tres áreas de investigación. Primero, la descripción de una infraestructura de detección generalizada, que facilita interacciones entre smartphones y otros dispositivos. Al permitir interacciones complejas para la captura de datos entre diversos sensores, dispositivos y fuentes de datos remotos, esta infraestructura consigue mejorar la calidad de la información y ahorrar energía en el dispositivo local. Segundo, la evaluación, a través de pruebas reales, de la idoneidad de las redes ad hoc como apoyo de los diversos procesos de comunicación requeridos en la monitorización generalizada. Este área incluye un método que incrementa la escalabilidad y reduce el coste de estas redes. Tercero, el diseño de dos mecanismos de percepción que permiten la provisión flexible de información en contextos de aprendizaje dinámicos y heterogéneos. Estos mecanismos descansan en la versatilidad de los smartphones, que pueden ser utilizados directamente como displays de percepción o como puentes de comunicación que habilitan la interacción con otros displays remotos del entorno. Diferentes aspectos del sistema propuesto han sido evaluados a través de simulaciones, experimentos reales, estudios de usuarios y evaluaciones de prototipos. La evaluación experimental proporcionó evidencia empírica de la idoneidad del sistema para apoyar el desarrollo de soluciones de monitorización generalizadas. Además, las pruebas de concepto realizadas tanto en entornos de aprendizajes reales como en el laboratorio, aportaron indicadores cuantitativos y cualitativos de que estos mecanismos mejoran la calidad de la información de percepción y la experiencia del usuario.Postprint (published version

Design of an UAV swarm

This master thesis tries to give an overview on the general aspects involved in the design of an UAV swarm. UAV swarms are continuoulsy gaining popularity amongst researchers and UAV manufacturers, since they allow greater success rates in task accomplishing with reduced times. Appart from this, multiple UAVs cooperating between them opens a new field of missions that can only be carried in this way. All the topics explained within this master thesis will explain all the agents involved in the design of an UAV swarm, from the communication protocols between them, navigation and trajectory analysis and task allocation

Development and Evaluation of Methodologies for Vulnerability Analysis of Ad-hoc Routing Protocols

This thesis presents a number methodologies for computer assisted vulnerability analysis of routing protocols in ad-hoc networks towards the goal of automating the process of finding vulnerabilities (possible attacks) on such network routing protocols and correcting the protocols. The methodologies developed are (each) based on a different representation (model) of the routing protocol, which model predicated the quantitative methods and algorithms used. Each methodology is evaluated with respect to effectiveness feasibility and possibility of application to realistically sized networks. The first methodology studied is based on formal models of the protocols and associated symbolic partially ordered model checkers. Using this methodology, a simple attack in unsecured AODV is demonstrated. An extension of the Strands model is developed which is suitable for such routing protocols. The second methodology is based on timed-probabilistic formal models which is necessary due to the probabilistic nature of ad-hoc routing protocols. This second methodolgy uses natural extensions of the first one. A nondeterministic-timing model based on partially ordered events is considered for application towards the model checking problem. Determining probabilities within this structure requires the calculation of the volume of a particular type of convex volume, which is known to be #P-hard. A new algorithm is derived, exploiting the particular problem structure, that can be used to reduce the amount of time used to compute these quantities over conventional algorithms. We show that timed-probabilistic formal models can be linked to trace-based techniques by sampling methods, and conversely how execution traces can serve as starting points for formal exploration of the state space. We show that an approach combining both trace-based and formal methods can have faster convergence than either alone on a set of problems. However, the applicability of both of these techniques to ad-hoc network routing protocols is limited to small networks and relatively simple attacks. We provide evidence to this end. To address this limitation, a final technique employing only trace-based methods within an optimization framework is developed. In an application of this third methodology, it is shown that it can be used to evaluate the effects of a simple attack on OLSR. The result can be viewed (from a certain perspective) as an example of automatically discovering a new attack on the OLSR routing protocol

Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)

This aim of paper is to presents the development of a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The goal of the project was the training in geospatial data acquiring and processing for students attending Architecture and Engineering Courses, in order to start up a team of "volunteer mappers". Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing. The proposed area for testing the training activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According to other international experiences, the group is expected to be active after emergencies in order to upgrade maps, using data acquired by typical geomatic methods and techniques such as terrestrial and aerial Lidar, close-range and aerial photogrammetry, topographic and GNSS instruments etc.; or by non conventional systems and instruments such us UAV, mobile mapping etc. The ultimate goal is to implement a WebGIS platform to share all the data collected with local authorities and the Civil Protectio

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms