D3M: multicast listener mobility support mechanisms over distributed mobility anchoring architectures

The explosion in mobile data traffic is a driver for future network operator technologies, given its large potential to affect both network performance and generated revenue. The concept of distributed mobility management (DMM) has emerged in order to overcome efficiency-wise limitations in centralized mobility approaches, proposing not only the distribution of anchoring functions but also dynamic mobility activation sensitive to the applications needs. Nevertheless, there is not an acceptable solution for IP multicast in DMM environments, as the first proposals based on MLD Proxy are prone to tunnel replication problem or service disruption. We propose the application of PIM-SM in mobility entities as an alternative solution for multicast support in DMM, and introduce an architecture enabling mobile multicast listeners support over distributed anchoring frameworks in a network-efficient way. The architecture aims at providing operators with flexible options to provide multicast mobility, supporting three modes: the first one introduces basic IP multicast support in DMM; the second improves subscription time through extensions to the mobility protocol, obliterating the dependence on MLD protocol; and the third enables fast listener mobility by avoiding potentially slow multicast tree convergence latency in larger infrastructures, by benefiting from mobility tunnels. The different modes were evaluated by mathematical analysis regarding disruption time and packet loss during handoff against several parameters, total and tunneling packet delivery cost, and regarding packet and signaling overhead.

Component Architecture for Context-Aware Applications

Mobiililaitteisiin tehdyt sovellukset ovat nykyään laajassa käytössä. Mobiilisovellukset tarjoavat käyttäjälleen usein tietyn ennalta määritellyn toiminnallisuuden eivätkä ne pysty mukautumaan vaihtelevaan käyttöympäristöönsä. Jos sovellus olisi tietoinen käyttöympäristöstään ja sen muutoksista, se voisi tarjota käyttäjälleen tilanteeseen sopivia ominaisuuksia. Käyttöympäristöstään tietoiset hajautetut sovellukset tarvitsevat kuitenkin huomattavasti perinteisiä sovelluksia monimutkaisemman arkkitehtuurin toimiakseen. Tässä työssä esitellään hajautetuille ja kontekstitietoisille sovelluksille tarkoitettu ohjelmistoarkkitehtuuri. Työ perustuu Oulun yliopiston CAPNET-tutkimusprojektissa kehitettyyn, mobiilisovelluksille tarkoitettuun arkkitehtuuriin. Tämän työn tarkoituksena on tarjota ratkaisuja niihin puutteisiin, jotka tulivat esille CAPNET-arkkitehtuurin kehitys- ja testausvaiheessa. Esimerkiksi arkkitehtuurin komponenttien määrittelyä tulisi tarkentaa ja ne tulisi jakaa horisontaalisiin kerroksiin niiden ominaisuuksien ja alustariippuvuuden mukaisesti. Työssä luodaan katsaus olemassa oleviin teknologioihin jotka tukevat hajautettujen ja kontekstitietoisten järjestelmien kehittämistä. Myös niiden soveltumista CAPNET-arkkitehtuuriin analysoidaan. Työssä esitellään CAPNET-arkkitehtuuri ja ehdotetaan uutta arkkitehtuuria ja komponenttien kerrosjaottelua. Ehdotuksessa arkkitehtuurin komponentit ja järjestelmän rakenne määritellään ja mallinnetaan UML-menetelmällä. Työn tuloksena on arkkitehtuurimäärittely, joka jakaa nykyisen arkkitehtuurin komponentit kerroksiin. Komponenttien rajapinnat on määritelty selkeästi ja tarkasti. Työ tarjoaa myös projektiryhmälle hyvän lähtökohdan uuden arkkitehtuurin suunnittelulle ja toteuttamiselle.

Comportamento sócio-espacial de pessoas em movimento :um estudo exploratório no calçadão da Avenida Engenheiro Roberto Freire

People-environment interaction, focus of Environmental Psychology studies, presupposes that space influences behavior and vice-versa. Despite of the importance of dynamic reciprocity, there are a few works that treat the mobility condition of the people experimenting space. The present study investigates environmental perception of users of the Engenheiro Roberto Freire Avenue sidewalk, one of the few places in Natal for physical activities practicing, where most people are in intense and continuous movement. A few questions for this study where made: In what way does the individual realize the environment while he is moving? How do reciprocal man-environment relations occur there, according to a mobility context? What are the main difficulties and easiness in man-environment interaction under this condition? The search for these answers is based on concepts of social-spatial human behavior - especially personal space, territoriality, density and crowding and contributions of Barker´s Ecologycal Psychology. Considering that the physical space in this case is multifaceted and the perception of theses scenarios is governed by multiples senses and stimuli, it was defined a multi-methodological route: (i) observation participative in loco; (ii) identification of the main behavior settings at the area; (iii) categorization of the activities occurring at the place; (iv) application of a semi-structured interview; (v) images registered and (vi) construction of the researcher s log. The perception of oneself and others in movement in the environment, immersed in a intricate web of inter-actions, makes people develop mobility strategies, many times unconsciously, with the aim of ensuring satisfaction in its activities. Since the Eng. Roberto Freire Avenue sidewalk is an equipment public-urban largely used by the population of Natal, the reflection of the mobility effectiveness in the users environmental perception is expected, providing suggestions for future studies in this field of knowledge

Coordination and Control of Autonomous Mobile Robots Swarms by using Particle Swarm Optimization Algorithm and Consensus Theory

This thesis presents some different techniques designed to drive a swarm of robots in an a-priori unknown environment in order to move the group from a starting area to a final one avoiding obstacles. The presented techniques are based on two different theories used alone or in combination: Swarm Intelligence (SI) and Graph Theory. Both theories are based on the study of interactions between different entities (also called agents or units) in Multi- Agent Systems (MAS). The first one belongs to the Artificial Intelligence context and the second one to the Distributed Systems context. These theories, each one from its own point of view, exploit the emergent behaviour that comes from the interactive work of the entities, in order to achieve a common goal. The features of flexibility and adaptability of the swarm have been exploited with the aim to overcome and to minimize difficulties and problems that can affect one or more units of the group, having minimal impact to the whole group and to the common main target. Another aim of this work is to show the importance of the information shared between the units of the group, such as the communication topology, because it helps to maintain the environmental information, detected by each single agent, updated among the swarm. Swarm Intelligence has been applied to the presented technique, through the Particle Swarm Optimization algorithm (PSO), taking advantage of its features as a navigation system. The Graph Theory has been applied by exploiting Consensus and the application of the agreement protocol with the aim to maintain the units in a desired and controlled formation. This approach has been followed in order to conserve the power of PSO and to control part of its random behaviour with a distributed control algorithm like Consensus.

Progettazione ed analisi di algoritmi di mobilità controllata per reti mesh aeree con vincoli di copertura e persistenza

In questo lavoro di tesi verrà presentata l’implementazione di due algoritmi di Deployment e gestione di uno sciame di dispositivi UAV (Unmanned Aerial Vehicles). L’interesse scientifico su cui si fonda quest'analisi ha origine nelle enormi potenzialità degli UAV che garantiscono un'esplorazione aerea di aree pericolose in contesti di emergenze quali ad esempio scenari post catastrofe. La problematica principale affrontata sarà quella della gestione continuativa dell'area disastrata fornendo un algoritmo di schedulazione della cooperazione degli UAV alternando periodi attivi con quelli di ricarica dei dispositivi.

Arquitetura de rede com suporte à mobilidade de fluxo IP e ao gerenciamento de Mobilidade Distribuído (DMM)

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2016.

Middleware for distributed context-aware systems

Context-aware systems represent extremely complex and heterogeneous distributed systems, composed of sensors, actuators, application components, and a variety of context processing components that manage the flow of context information between the sensors/actuators and applications. The need for middleware to seamlessly bind these components together is well recognised. Numerous attempts to build middleware or infrastructure for context-aware systems have been made, but these have provided only partial solutions; for instance, most have not adequately addressed issues such as mobility, fault tolerance or privacy. One of the goals of this paper is to provide an analysis of the requirements of a middleware for context-aware systems, drawing from both traditional distributed system goals and our experiences with developing context-aware applications. The paper also provides a critical review of several middleware solutions, followed by a comprehensive discussion of our own PACE middleware. Finally, it provides a comparison of our solution with the previous work, highlighting both the advantages of our middleware and important topics for future research.

Distributed energy resources management with cyber-physical SCADA in the context of future smart grids

In the energy management of a small power system, the scheduling of the generation units is a crucial problem for which adequate methodologies can maximize the performance of the energy supply. This paper proposes an innovative methodology for distributed energy resources management. The optimal operation of distributed generation, demand response and storage resources is formulated as a mixed-integer linear programming model (MILP) and solved by a deterministic optimization technique CPLEX-based implemented in General Algebraic Modeling Systems (GAMS). The paper deals with a vision for the grids of the future, focusing on conceptual and operational aspects of electrical grids characterized by an intensive penetration of DG, in the scope of competitive environments and using artificial intelligence methodologies to attain the envisaged goals. These concepts are implemented in a computational framework which includes both grid and market simulation.

Demsi - a demand response simulator in the context of intensive use of distributed generation

Demand response can play a very relevant role in future power systems in which distributed generation can help to assure service continuity in some fault situations. This paper deals with the demand response concept and discusses its use in the context of competitive electricity markets and intensive use of distributed generation. The paper presents DemSi, a demand response simulator that allows studying demand response actions and schemes using a realistic network simulation based on PSCAD. Demand response opportunities are used in an optimized way considering flexible contracts between consumers and suppliers. A case study evidences the advantages of using flexible contracts and optimizing the available generation when there is a lack of supply.

Code offloading on real-time multimedia systems: a framework for handling code mobility and code offloading in a QoS aware environment

Actualmente, os smartphones e outros dispositivos móveis têm vindo a ser dotados com cada vez maior poder computacional, sendo capazes de executar um vasto conjunto de aplicações desde simples programas de para tirar notas até sofisticados programas de navegação. Porém, mesmo com a evolução do seu hardware, os actuais dispositivos móveis ainda não possuem as mesmas capacidades que os computadores de mesa ou portáteis. Uma possível solução para este problema é distribuir a aplicação, executando partes dela no dispositivo local e o resto em outros dispositivos ligados à rede. Adicionalmente, alguns tipos de aplicações como aplicações multimédia, jogos electrónicos ou aplicações de ambiente imersivos possuem requisitos em termos de Qualidade de Serviço, particularmente de tempo real. Ao longo desta tese é proposto um sistema de execução de código remota para sistemas distribuídos com restrições de tempo-real. A arquitectura proposta adapta-se a sistemas que necessitem de executar periodicamente e em paralelo mesmo conjunto de funções com garantias de tempo real, mesmo desconhecendo os tempos de execução das referidas funções. A plataforma proposta foi desenvolvida para sistemas móveis capazes de executar o Sistema Operativo Android.

Service-oriented mobility of java code in web services-based architectures

Dissertação apresentada na Faculdade de Ciências e Tecnologias da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia Informática

Pedestrian Priority Zones in the Context of Urban Mobility and Valorization of Public Space

The second half of the XX century was marked by a great increase in the number of people living in cities. Urban agglomerations became poles of attraction for migration flows and these phenomena, coupled with growing car-ownership rates, resulted in the fact that modern transport systems are characterized by large number of users and traffic modes. The necessity to organize these complex systems and to provide space for different traffic modes changed the way cities look. Urban areas had to cope with traffic flows, and as a result nowadays typical street pattern consists of a road for motorized vehicles, a cycle lane (in some cases), pavement for pedestrians, parking and a range of crucial signage to facilitate navigation and make mobility more secure. However, this type of street organization may not be desirable in certain areas, more specifically, in the city centers. Downtown areas have always been places where economic, leisure, social and other types of facilities are concentrated, not surprisingly, they often attract large number of people and this frequently results in traffic jams, air and noise pollution, thus creating unpleasant environment. Besides, excessive traffic signage in central locations can harm the image and perception of a place, this relates in particular to historical centers with architectural heritage.

Radio mobility in the digital era: interactivity, participation and content share possibilities in Iberian broadcasters

In the context of the scientific research into radio, recent years have encouraged many theories about the meaning of a post-radio (Oliveira & Portela, 2011), thus enlisting several parameters regarding the inclusion of contemporary radio in the digital and online environments. This digital migration has led to the development of mobile applications for radio, broadening the communicative potential of audiences (Aguado, Feijoo & Martínez, 2013), as well as promoting convergence of interactive content among listeners-users. Aware of this opportunity, the main broadcasters in Spain and Portugal have broadened their radiophonic scope to the mobile platform, especially geared towards smartphones through the development of mobile applications, commonly known as apps (Cerezo, 2010). As a symbol of a culture in permanent changing, smartphones not only provide greater easiness in terms of access and interaction, but also afford larger opportunities for disseminating content among audiences, a phenomenon that some studies have labelled as user distributed content (Villi, 2012). This article presents an exploratory analysis of the current policies of the main Spanish and Portuguese radio broadcasters regarding mobile applications, evaluating the different levels of interaction and participation in these platforms. This observation led to the conclusion, among other findings, that the mobile platform represents a supplementary channel for traditional FM radio, rather than a new medium with its own language and expression.

Context as a Service

In the vision of Mark Weiser on ubiquitous computing, computers are disappearing from the focus of the users and are seamlessly interacting with other computers and users in order to provide information and services. This shift of computers away from direct computer interaction requires another way of applications to interact without bothering the user. Context is the information which can be used to characterize the situation of persons, locations, or other objects relevant for the applications. Context-aware applications are capable of monitoring and exploiting knowledge about external operating conditions. These applications can adapt their behaviour based on the retrieved information and thus to replace (at least a certain amount) the missing user interactions. Context awareness can be assumed to be an important ingredient for applications in ubiquitous computing environments. However, context management in ubiquitous computing environments must reflect the specific characteristics of these environments, for example distribution, mobility, resource-constrained devices, and heterogeneity of context sources. Modern mobile devices are equipped with fast processors, sufficient memory, and with several sensors, like Global Positioning System (GPS) sensor, light sensor, or accelerometer. Since many applications in ubiquitous computing environments can exploit context information for enhancing their service to the user, these devices are highly useful for context-aware applications in ubiquitous computing environments. Additionally, context reasoners and external context providers can be incorporated. It is possible that several context sensors, reasoners and context providers offer the same type of information. However, the information providers can differ in quality levels (e.g. accuracy), representations (e.g. position represented in coordinates and as an address) of the offered information, and costs (like battery consumption) for providing the information. In order to simplify the development of context-aware applications, the developers should be able to transparently access context information without bothering with underlying context accessing techniques and distribution aspects. They should rather be able to express which kind of information they require, which quality criteria this information should fulfil, and how much the provision of this information should cost (not only monetary cost but also energy or performance usage). For this purpose, application developers as well as developers of context providers need a common language and vocabulary to specify which information they require respectively they provide. These descriptions respectively criteria have to be matched. For a matching of these descriptions, it is likely that a transformation of the provided information is needed to fulfil the criteria of the context-aware application. As it is possible that more than one provider fulfils the criteria, a selection process is required. In this process the system has to trade off the provided quality of context and required costs of the context provider against the quality of context requested by the context consumer. This selection allows to turn on context sources only if required. Explicitly selecting context services and thereby dynamically activating and deactivating the local context provider has the advantage that also the resource consumption is reduced as especially unused context sensors are deactivated. One promising solution is a middleware providing appropriate support in consideration of the principles of service-oriented computing like loose coupling, abstraction, reusability, or discoverability of context providers. This allows us to abstract context sensors, context reasoners and also external context providers as context services. In this thesis we present our solution consisting of a context model and ontology, a context offer and query language, a comprehensive matching and mediation process and a selection service. Especially the matching and mediation process and the selection service differ from the existing works. The matching and mediation process allows an autonomous establishment of mediation processes in order to transfer information from an offered representation into a requested representation. In difference to other approaches, the selection service selects not only a service for a service request, it rather selects a set of services in order to fulfil all requests which also facilitates the sharing of services. The approach is extensively reviewed regarding the different requirements and a set of demonstrators shows its usability in real-world scenarios.