Coordination of Mobile Mules via Facility Location Strategies

In this paper, we study the problem of wireless sensor network (WSN) maintenance using mobile entities called mules. The mules are deployed in the area of the WSN in such a way that would minimize the time it takes them to reach a failed sensor and fix it. The mules must constantly optimize their collective deployment to account for occupied mules. The objective is to define the optimal deployment and task allocation strategy for the mules, so that the sensors' downtime and the mules' traveling distance are minimized. Our solutions are inspired by research in the field of computational geometry and the design of our algorithms is based on state of the art approximation algorithms for the classical problem of facility location. Our empirical results demonstrate how cooperation enhances the team's performance, and indicate that a combination of k-Median based deployment with closest-available task allocation provides the best results in terms of minimizing the sensors' downtime but is inefficient in terms of the mules' travel distance. A k-Centroid based deployment produces good results in both criteria.Comment: 12 pages, 6 figures, conferenc

Service Provisioning in Mobile Networks Through Distributed Coordinated Resource Management

The pervasiveness of personal computing platforms offers an unprecedented opportunity to deploy large-scale services that are distributed over wide physical spaces. Two major challenges face the deployment of such services: the often resource-limited nature of these platforms, and the necessity of preserving the autonomy of the owner of these devices. These challenges preclude using centralized control and preclude considering services that are subject to performance guarantees. To that end, this thesis advances a number of new distributed resource management techniques that are shown to be effective in such settings, focusing on two application domains: distributed Field Monitoring Applications (FMAs), and Message Delivery Applications (MDAs). In the context of FMA, this thesis presents two techniques that are well-suited to the fairly limited storage and power resources of autonomously mobile sensor nodes. The first technique relies on amorphous placement of sensory data through the use of novel storage management and sample diffusion techniques. The second approach relies on an information-theoretic framework to optimize local resource management decisions. Both approaches are proactive in that they aim to provide nodes with a view of the monitored field that reflects the characteristics of queries over that field, enabling them to handle more queries locally, and thus reduce communication overheads. Then, this thesis recognizes node mobility as a resource to be leveraged, and in that respect proposes novel mobility coordination techniques for FMAs and MDAs. Assuming that node mobility is governed by a spatio-temporal schedule featuring some slack, this thesis presents novel algorithms of various computational complexities to orchestrate the use of this slack to improve the performance of supported applications. The findings in this thesis, which are supported by analysis and extensive simulations, highlight the importance of two general design principles for distributed systems. First, a-priori knowledge (e.g., about the target phenomena of FMAs and/or the workload of either FMAs or DMAs) could be used effectively for local resource management. Second, judicious leverage and coordination of node mobility could lead to significant performance gains for distributed applications deployed over resource-impoverished infrastructures

Organizations and cyber crime: An analysis of the nature of groups engaged in cyber crime

This paper explores the nature of groups engaged in cyber crime. It briefly outlines the definition and scope of cyber crime, theoretical and empirical challenges in addressing what is known about cyber offenders, and the likely role of organized crime groups. The paper gives examples of known cases that illustrate individual and group behaviour, and motivations of typical offenders, including state actors. Different types of cyber crime and different forms of criminal organization are described drawing on the typology suggested by McGuire (2012). It is apparent that a wide variety of organizational structures are involved in cyber crime. Enterprise or profit-oriented activities, and especially cyber crime committed by state actors, appear to require leadership, structure, and specialisation. By contrast, protest activity tends to be less organized, with weak (if any) chain of command

EU organised crime threat assessment 2011.

The bi–annual report, which assesses current and expected trends in organised crime affecting the European Union, explores how a new criminal landscape is emerging, marked increasingly by highly mobile and flexible groups operating in multiple jurisdictions and criminal sectors. "Organised crime is a multi–billion euro business in Europe and it is growing in scale. The further expansion of Internet and mobile technologies, the proliferation of illicit trafficking routes and methods as well as opportunities offered by the global economic crisis, have all contributed to the development of a more potent threat from organised crime," says Rob Wainwright, Director of Europol. The report highlights the fact that criminal groups are increasingly multi–commodity and poly–criminal in their activities, gathering diverse portfolios of criminal business interests, improving their resilience at a time of economic austerity and strengthening their capability to identify and exploit new illicit markets. Activities such as carbon credit fraud, payment card fraud and commodity counterfeiting attract increasing interest due to a lower level of perceived risk. The OCTA estimates for the first time that organised crime groups derived more than 1.5 billion euro from payment card fraud in the EU. While the introduction of the EMV chip standard provides a very high level of protection for payment card transactions within the EU, lack of wholesale implementation in other regions has compelled EU card issuers to retain magnetic strips. As a result, half the fraudulent withdrawals made with cloned EU payment cards are currently made outside the EU. Strong levels of cooperation exist between different organised crime groups, more than ever before, transcending national, ethnic, and business differences. An increasingly collaborative atmosphere has also intensified the practice of barter, in which illicit commodities are exchanged rather than purchased with cash. This has made organised crime activities less visible to authorities targeting criminal assets

Opportunistic data collection and routing in segmented wireless sensor networks

La surveillance régulière des opérations dans les aires de manoeuvre (voies de circulation et pistes) et aires de stationnement d'un aéroport est une tâche cruciale pour son fonctionnement. Les stratégies utilisées à cette fin visent à permettre la mesure des variables environnementales, l'identification des débris (FOD) et l'enregistrement des statistiques d'utilisation de diverses sections de la surface. Selon un groupe de gestionnaires et contrôleurs d'aéroport interrogés, cette surveillance est un privilège des grands aéroports en raison des coûts élevés d'acquisition, d'installation et de maintenance des technologies existantes. Les moyens et petits aéroports se limitent généralement à la surveillance de quelques variables environnementales et des FOD effectuée visuellement par l'homme. Cette dernière activité impose l'arrêt du fonctionnement des pistes pendant l'inspection. Dans cette thèse, nous proposons une solution alternative basée sur les réseaux de capteurs sans fil (WSN) qui, contrairement aux autres méthodes, combinent les propriétés de faible coût d'installation et maintenance, de déploiement rapide, d'évolutivité tout en permettant d'effectuer des mesures sans interférer avec le fonctionnement de l'aéroport. En raison de la superficie d'un aéroport et de la difficulté de placer des capteurs sur des zones de transit, le WSN se composerait d'une collection de sous-réseaux isolés les uns des autres et du puits. Pour gérer cette segmentation, notre proposition s'appuie sur l'utilisation opportuniste des véhicules circulants dans l'aéroport considérés alors comme un type spécial de nœud appelé Mobile Ubiquitous LAN Extension (MULE) chargé de collecter les données des sous-réseaux le long de son trajet et de les transférer vers le puits. L'une des exigences pour le déploiement d'un nouveau système dans un aéroport est qu'il cause peu ou pas d'interruption des opérations régulières. C'est pourquoi l'utilisation d'une approche opportuniste basé sur des MULE est privilégiée dans cette thèse. Par opportuniste, nous nous référons au fait que le rôle de MULE est joué par certains des véhicules déjà existants dans un aéroport et effectuant leurs déplacements normaux. Et certains nœuds des sous- réseaux exploiteront tout moment de contact avec eux pour leur transmettre les données à transférer ensuite au puits. Une caractéristique des MULEs dans notre application est qu'elles ont des trajectoires structurées (suivant les voies de circulation dans l'aéroport), en ayant éventuellement un contact avec l'ensemble des nœuds situés le long de leur trajet (appelés sous-puits). Ceci implique la nécessité de définir une stratégie de routage dans chaque sous-réseau, capable d'acheminer les données collectées des nœuds vers les sous-puits et de répartir les paquets de données entre eux afin que le temps en contact avec la MULE soit utilisé le plus efficacement possible. Dans cette thèse, nous proposons un protocole de routage remplissant ces fonctions. Le protocole proposé est nommé ACME (ACO-based routing protocol for MULE-assisted WSNs). Il est basé sur la technique d'Optimisation par Colonies de Fourmis. ACME permet d'assigner des nœuds à des sous-puits puis de définir les chemins entre eux, en tenant compte de la minimisation de la somme des longueurs de ces chemins, de l'équilibrage de la quantité de paquets stockés par les sous-puits et du nombre total de retransmissions. Le problème est défini comme une tâche d'optimisation multi-objectif qui est résolue de manière distribuée sur la base des actions des nœuds dans un schéma collaboratif. Nous avons développé un environnement de simulation et effectué des campagnes de calculs dans OMNeT++ qui montrent les avantages de notre protocole en termes de performances et sa capacité à s'adapter à une grande variété de topologies de réseaux.The regular monitoring of operations in both movement areas (taxiways and runways) and non-movement areas (aprons and aircraft parking spots) of an airport, is a critical task for its functioning. The set of strategies used for this purpose include the measurement of environmental variables, the identification of foreign object debris (FOD), and the record of statistics of usage for diverse sections of the surface. According to a group of airport managers and controllers interviewed by us, the wide monitoring of most of these variables is a privilege of big airports due to the high acquisition, installation and maintenance costs of most common technologies. Due to this limitation, smaller airports often limit themselves to the monitoring of environmental variables at some few spatial points and the tracking of FOD performed by humans. This last activity requires stopping the functioning of the runways while the inspection is conducted. In this thesis, we propose an alternative solution based on Wireless Sensor Network (WSN) which, unlike the other methods/technologies, combines the desirable properties of low installation and maintenance cost, scalability and ability to perform measurements without interfering with the regular functioning of the airport. Due to the large extension of an airport and the difficulty of placing sensors over transit areas, the WSN might result segmented into a collection of subnetworks isolated from each other and from the sink. To overcome this problem, our proposal relies on a special type of node called Mobile Ubiquitous LAN Extension (MULE), able to move over the airport surface, gather data from the subnetworks along its way and eventually transfer it to the sink. One of the main demands for the deployment of any new system in an airport is that it must have little or no interference with the regular operations. This is why the use of an opportunistic approach for the transfer of data from the subnetworks to the MULE is favored in this thesis. By opportunistic we mean that the role of MULE will be played by some of the typical vehicles already existing in an airport doing their normal displacements, and the subnetworks will exploit any moment of contact with them to forward data to the sink. A particular characteristic of the MULEs in our application is that they move along predefined structured trajectories (given by the layout of the airport), having eventual contact with the set of nodes located by the side of the road (so-called subsinks). This implies the need for a data routing strategy to be used within each subnetwork, able to lead the collected data from the sensor nodes to the subsinks and distribute the data packets among them so that the time in contact with the MULE is used as efficiently as possible. In this thesis, we propose a routing protocol which undertakes this task. Our proposed protocol is named ACME, standing for ACO-based routing protocol for MULE-assisted WSNs. It is founded on the well known Ant Colony Optimization (ACO) technique. The main advantage of ACO is its natural fit to the decentralized nature of WSN, which allows it to perform distributed optimizations (based on local interactions) leading to remarkable overall network performance. ACME is able to assign sensor nodes to subsinks and generate the corresponding multi-hop paths while accounting for the minimization of the total path length, the total subsink imbalance and the total number of retransmissions. The problem is defined as a multi-objective optimization task which is resolved in a distributed manner based on actions of the sensor nodes acting in a collaborative scheme. We conduct a set of computational experiments in the discrete event simulator OMNeT++ which shows the advantages of our protocol in terms of performance and its ability to adapt to a variety of network topologie

In-depth assessment of the public agricultural extension system of Ethiopia and recommendations for improvement:

Eighty-three percent of the population of Ethiopia depends directly on agriculture for their livelihoods, while many others depend on agriculture-related cottage industries such as textiles, leather, and food oil processing. Agriculture contributes about 46.3 percent of gross domestic product (GDP) (World Bank 2008) and up to 90 percent of total export earnings. As part of the current five-year (2006–2011) Plan for Accelerated and Sustained Development to End Poverty (PASDEP), the government is continuing to invest heavily in agriculture. A core part of the government's investment in agriculture is the public agricultural extension system. This study was conducted to assess the strengths and constraints of the public extension system and to provide suggestions on “best fit” solutions and their scale-up opportunities. The review used a variety of analytical tools to develop the overall findings, including extensive field visits to six of nine regions in Ethiopia; interviews with farmer trainees at farmer training centers (FTCs), more than 100 extension personnel, extension experts, nongovernmental organization (NGO) groups, and government representatives; and a literature review on Ethiopian extension. The study assessed strengths and constraints in the field-level extension system, the ATVET system, and the extension institutional environment. The researchers also considered the overall enabling environment within which extension operates. The field-level extension service has a strong foundation of FTCs and trained development agents (DAs) already in place in the field. Roughly 8,489 FTCs have been created throughout Ethiopia, and about 62,764 DAs have been trained in total, with a reported 45,812 staffed on location. Woreda (district) and regional offices are adequately staffed. DAs and woreda staff have strong technical skills and theoretical knowledge, and are generally trained as specialists. Pockets of entrepreneurialism and innovation exist in specific FTCs and woredas. While acknowledging these strengths, the researchers also identified several sets of constraints within the field-level extension system that will require attention. Basic infrastructure and resources at the FTC and woreda level remain a major constraint, particularly in relation to operating funds: the vast majority of FTCs and kebeles do not have operating equipment or inputs to pursue typical extension activities on the demonstration farm. There are major “soft” skill gaps for DAs and subject matter specialists (SMSs) in the FTCs and woredas, and their ability to serve farmers is limited given a lack of practical skills. Finally, the overall field-level system is often limited in its ability to meet farmer needs and demands; mechanisms to make it more farmer-driven and market-oriented would yield greater results. The authors employed a similar approach at the ATVET level to identify strengths and constraints. Strengths at the ATVET level include a strong record of training broad groups of DAs, a strong technical curriculum, and some pockets of innovation and practical training, including linkages to markets and farmers. Constraints include limited success in enabling DAs to gain practical experience, particularly related to their internships at the woreda level; limited linkages to the broader educational system and research system in Ethiopia; and a general lack of resources to effectively transmit the required skill set to DAs. The countrywide enabling environment in which extension operates is critical to extension efforts. Various aspects of the enabling environment were considered, including seed and other inputs, water management, and credit systems, as well as producer groups. Constraints were also assessed, leading to the conclusion that the enabling environment requires strengthening, particularly in the areas of seed and credit, if extension is to achieve its full potential impact.trained development agents (DA), farmer training centers (FTC), ATVET system, Extension, Agriculture,