A COGNITIVE ARCHITECTURE FOR AMBIENT INTELLIGENCE

L’Ambient Intelligence (AmI) è caratterizzata dall’uso di sistemi pervasivi per monitorare l’ambiente e modificarlo secondo le esigenze degli utenti e rispettando vincoli definiti globalmente. Questi sistemi non possono prescindere da requisiti come la scalabilità e la trasparenza per l’utente. Una tecnologia che consente di raggiungere questi obiettivi è rappresentata dalle reti di sensori wireless (WSN), caratterizzate da bassi costi e bassa intrusività. Tuttavia, sebbene in grado di effettuare elaborazioni a bordo dei singoli nodi, le WSN non hanno da sole le capacità di elaborazione necessarie a supportare un sistema intelligente; d’altra parte senza questa attività di pre-elaborazione la mole di dati sensoriali può facilmente sopraffare un sistema centralizzato con un’eccessiva quantità di dettagli superflui. Questo lavoro presenta un’architettura cognitiva in grado di percepire e controllare l’ambiente di cui fa parte, basata su un nuovo approccio per l’estrazione di conoscenza a partire dai dati grezzi, attraverso livelli crescenti di astrazione. Le WSN sono utilizzate come strumento sensoriale pervasivo, le cui capacità computazionali vengono utilizzate per pre-elaborare i dati rilevati, in modo da consentire ad un sistema centralizzato intelligente di effettuare ragionamenti di alto livello. L’architettura proposta è stata utilizzata per sviluppare un testbed dotato degli strumenti hardware e software necessari allo sviluppo e alla gestione di applicazioni di AmI basate su WSN, il cui obiettivo principale sia il risparmio energetico. Per fare in modo che le applicazioni di AmI siano in grado di comunicare con il mondo esterno in maniera affidabile, per richiedere servizi ad agenti esterni, l’architettura è stata arricchita con un protocollo di gestione distribuita della reputazione. È stata inoltre sviluppata un’applicazione di esempio che sfrutta le caratteristiche del testbed, con l’obiettivo di controllare la temperatura in un ambiente lavorativo. Quest’applicazione rileva la presenza dell’utente attraverso un modulo per la fusione di dati multi-sensoriali basato su reti bayesiane, e sfrutta questa informazione in un controllore fuzzy multi-obiettivo che controlla gli attuatori sulla base delle preferenze dell’utente e del risparmio energetico.Ambient Intelligence (AmI) systems are characterized by the use of pervasive equipments for monitoring and modifying the environment according to users’ needs, and to globally defined constraints. Furthermore, such systems cannot ignore requirements about ubiquity, scalability, and transparency to the user. An enabling technology capable of accomplishing these goals is represented by Wireless Sensor Networks (WSNs), characterized by low-costs and unintrusiveness. However, although provided of in-network processing capabilities, WSNs do not exhibit processing features able to support comprehensive intelligent systems; on the other hand, without this pre-processing activities the wealth of sensory data may easily overwhelm a centralized AmI system, clogging it with superfluous details. This work proposes a cognitive architecture able to perceive, decide upon, and control the environment of which the system is part, based on a new approach to knowledge extraction from raw data, that addresses this issue at different abstraction levels. WSNs are used as the pervasive sensory tool, and their computational capabilities are exploited to remotely perform preliminary data processing. A central intelligent unit subsequently extracts higher-level concepts in order to carry on symbolic reasoning. The aim of the reasoning is to plan a sequence of actions that will lead the environment to a state as close as possible to the users’ desires, taking into account both implicit and explicit feedbacks from the users, while considering global system-driven goals, such as energy saving. The proposed conceptual architecture was exploited to develop a testbed providing the hardware and software tools for the development and management of AmI applications based on WSNs, whose main goal is energy saving for global sustainability. In order to make the AmI system able to communicate with the external world in a reliable way, when some services are required to external agents, the architecture was enriched with a distributed reputation management protocol. A sample application exploiting the testbed features was implemented for addressing temperature control in a work environment. Knowledge about the user’s presence is obtained through a multi-sensor data fusion module based on Bayesian networks, and this information is exploited by a multi-objective fuzzy controller that operates on actuators taking into account users’ preference and energy consumption constraints

QoS-aware Mobile Web Services Discovery Using Utility Functions

Existing QoS-aware Web Services discovery architectures tend to focus solely on fulfilling the requirements of either the client or the provider. However, the interests of the provider and client are not equivalent. The provider’s goal is to maximize the profit and consume the least amount of resources. On the other hand, the client’s selection is determined by their own requirements which do not always reflect the real resource overheads. This research aims to provide a novel mobile Web Services discovery and selection method based on utility functions to balance the requirements for clients and providers. In the mobile environment, it is critical to conserve resource consumption in addition to fulfilling user requirements, as resources such as wireless network bandwidth and mobile device power are precious. The proposed service selection strategy enables service providers to balance the cost/performance ratios and utilize the network bandwidth more effectively, while the clients can still attain the functional and quality levels specified in the service request

An Investigation into Dynamic Web Service Composition Using a Simulation Framework

[Motivation] Web Services technology has emerged as a promising solution for creat- ing distributed systems with the potential to overcome the limitation of former distrib- uted system technologies. Web services provide a platform-independent framework that enables companies to run their business services over the internet. Therefore, many techniques and tools are being developed to create business to business/business to customer applications. In particular, researchers are exploring ways to build new services from existing services by dynamically composing services from a range of resources. [Aim] This thesis aims to identify the technologies and strategies cur- rently being explored for organising the dynamic composition of Web services, and to determine how extensively each of these has been demonstrated and assessed. In addition, the thesis will study the matchmaking and selection processes which are essential processes for Web service composition. [Research Method] We under- took a mapping study of empirical papers that had been published over the period 2000 to 2009. The aim of the mapping study was to identify the technologies and strategies currently being explored for organising the composition of Web services, and to determine how extensively each of these has been demonstrated and assessed. We then built a simulation framework to carry out some experiments on composition strategies. The rst experiment compared the results of a close replication of an ex- isting study with the original results in order to evaluate our close replication study. The simulation framework was then used to investigate the use of a QoS model for supporting the selection process, comparing this with the ranking technique in terms of their performance. [Results] The mapping study found 1172 papers that matched our search terms, from which 94 were classied as providing practical demonstration of ideas related to dynamic composition. We have analysed 68 of these in more detail. Only 29 provided a `formal' empirical evaluation. From these, we selected a `baseline' study to test our simulation model. Running the experiments using simulated data- sets have shown that in the rst experiment the results of the close replication study and the original study were similar in terms of their prole. In the second experiment, the results demonstrated that the QoS model was better than the ranking mechanism in terms of selecting a composite plan that has highest quality score. [Conclusions] No one approach to service composition seemed to meet all needs, but a number has been investigated more. The similarity between the results of the close replication and the original study showed the validity of our simulation framework and a proof that the results of the original study can be replicated. Using the simulation it was demonstrated that the performance of the QoS model was better than the ranking mechanism in terms of the overall quality for a selected plan. The overall objectives of this research are to develop a generic life-cycle model for Web service composition from a mapping study of the literature. This was then used to run simulations to replicate studies on matchmaking and compare selection methods

Smart PIN: performance and cost-oriented context-aware personal information network

The next generation of networks will involve interconnection of heterogeneous individual networks such as WPAN, WLAN, WMAN and Cellular network, adopting the IP as common infrastructural protocol and providing virtually always-connected network. Furthermore, there are many devices which enable easy acquisition and storage of information as pictures, movies, emails, etc. Therefore, the information overload and divergent content’s characteristics make it difficult for users to handle their data in manual way. Consequently, there is a need for personalised automatic services which would enable data exchange across heterogeneous network and devices. To support these personalised services, user centric approaches for data delivery across the heterogeneous network are also required. In this context, this thesis proposes Smart PIN - a novel performance and cost-oriented context-aware Personal Information Network. Smart PIN's architecture is detailed including its network, service and management components. Within the service component, two novel schemes for efficient delivery of context and content data are proposed: Multimedia Data Replication Scheme (MDRS) and Quality-oriented Algorithm for Multiple-source Multimedia Delivery (QAMMD). MDRS supports efficient data accessibility among distributed devices using data replication which is based on a utility function and a minimum data set. QAMMD employs a buffer underflow avoidance scheme for streaming, which achieves high multimedia quality without content adaptation to network conditions. Simulation models for MDRS and QAMMD were built which are based on various heterogeneous network scenarios. Additionally a multiple-source streaming based on QAMMS was implemented as a prototype and tested in an emulated network environment. Comparative tests show that MDRS and QAMMD perform significantly better than other approaches

Registry composition in ambient networks

Ambient Networks (AN) is a new networking concept for beyond 3G. It is a product of the European Union's Sixth Framework Program (FP6). Network composition is a core concept of ANs. It allows dynamic, scalable and uniform cooperation between heterogeneous networks. ANs can host various registries. These registries may be of different types (e.g. centralized, distributed), store heterogeneous types of information (e.g. raw data vs. aggregated data), and rely on different interfaces to access the stored information (i.e. protocols or programming interfaces). When ANs compose, the hosted registries need to compose. Registry composition is a sub-process of network composition. It provides seamless and autonomous access to the content of all of the registries in the composed network. This thesis proposes a new architecture for registry composition in ANs. This overall architecture is made up of four components: interface interworking, data interworking, negotiation and signaling. Interface interworking enables dynamic intercommunication between registries with heterogeneous interfaces. Data interworking involves dynamically overcoming data heterogeneity (e.g. format and granularity). Interface and data interworking go beyond static interworking using gateways, as done today. The negotiation component allows the negotiation of the composition agreement. Signaling coordinates and regulates the negotiation and the execution of the composition agreement. Requirements are derived and related work is reviewed. We propose a new functional entity and a new procedure to orchestrate the composition process. We also propose a new architecture for interface interworking, based on a peer to peer overlay network. We have built a proof-of-concept prototype. The interface-interworking component is used as the basis of our new architecture to data interworking. This architecture reuses mechanisms and algorithms from the federated data base area. The thesis proposes as well a new architecture for on-line negotiation. The architecture includes a template for composition agreement proposals, and a negotiation protocol that was validated using SPIN. A new signaling framework is also proposed. It is based on the IETF Next Step in Signaling (NSIS) framework and was validated using OPNET. Most of these contributions are now part of the AN concept, as defined by the European Union's Sixth Framework Progra

Data Driven Adaptation of Heterogeneous Service-Oriented Processes

Η με βάση τα δεδομένα προσαρμογή διαδικασιών αποτελεί μια επέκταση της έννοιας των Δυναμικών και με βάση τα Δεδομένα Καθοδηγουμενων Συστήματων (DDDAS) όπως αυτά έχουν καθοριστεί από την Δαρεμά. Συγεκριμένα όπως και στα DDDAS συστήματα η προσέγγιση μας επιτρέπει την προσφορά προσαρμοζόμενων διαδικασιών χρησιμοποιώντας διαθέσιμες πληροφορίες και υπηρεσίες. H προσφορά προσαρμοζόμενων διαδικασιών περιλαμβάνει την αναγνώριση και χρήση πιθανών εναλλακτικών μονοπατιών εκτέλεσης (ή διαδρομών) για την επίτευξη των στόχων και υπό-στόχων της κάθε διαδικασίας. Τα εναλλακτικά μονοπάτια λαμβάνουν υπόψη και χρησιμοποιούν σχετικές πληροφορίες ή/και υπηρεσίες (ή συνθέσεις υπηρεσιών). Για την αναζήτηση των πιθανών εναλλακτικών χρησιμοποιούνται τεχνικές από το χώρο της Τεχνητής Νοημοσύνης Σχεδιασμού (AI Planning) και της υπολογιστικής Πλαισίου (Context-Aware computing) κατά τον χρόνο διάθεσης της διαδικασίας. Κατά τον υπολογισμό των πιθανών εναλλακτικών, στόχος της προσέγγισης μας είναι η μείωση των βημάτων εκτέλεσης, δλδ του πλήθους των εργασιών της διαδικασίας που έχουν οριστείIn principle the Data-Driven Process Adaptation (DDPA) approach is based on the concept of Dynamic Data Driven Application Systems (DDDAS) as this is stated by Darema in [8]. In accordance to the DDDAS notion such systems support the utilization of appropriate information at specific decision points so as to make real systems more efficient. In this regard, DDPA accommodates the provision of adaptable service processes by exploiting the use of information available to the process environment in addition to existing services. Adaptation in the context of our approach includes the identification and use of possible alternatives for the achievement of the goals and sub-goals defined in a process; alternatives include the utilization of available related information and/or services (or service chains). Data-Driven adaptation incorporates AI planning and Context-Aware Computing techniques to support the identification of possible alternatives at deployment time. When calculating the possible alternatives the goal of our approach is to reduce the number of steps, i.e. number of process tasks, defined in the original process

Distributed discovery and management of alternate paths with enhanced quality of service in the internet

La convergence de récentes avancées technologiques permet l'émergence de nouveaux environnements informatiques pervasifs, dans lesquels des terminaux en réseaux coopèrent et communiquent de manière transparente pour les utilisateurs. Ces utilisateurs demandent des fonctionalités de plus en plus avancées de la part de ces terminaux. Etant données les limites intrinsèques des terminaux mobiles, ces fonctionalités, au lieu d'être directement implémentées dans les terminaux, sont appelées à être fournies par des fournisseurs de services situés à la périphérie du réseau. Ce derniers devient alors une source illimitée de services, et non plus seulement un medium de communication. Ces services, ou applications d'overlays, sont formés de plusieurs éléments applicatifs distribués qui coopèrent et communiquent entre eux via un réseau de recouvrement dynamique particulier, une association d'overlay. La Qualité de Service (QdS) perçue par les utilisateurs d'une application d'overlay dépend de la QdS existant au niveau des chemins de communications qui forment l'association d'overlay correspondante. Cette thèse montre qu'il est possible de fournir de la QdS à une application d'overlay en utilisant des chemins Internet alternatifs, résultant de la composition de chemins distincts. De plus, cette thèse montre également qu'il est possible de découvrir, sélectionner, et composer d'une manière distribuée ces chemins élémentaires, au sein d'une communauté comprenant un nombre important d'entités paires (telles que les précédents fournisseurs de services). Les principales contributions de cette thèse sont : i) une description et une analyse des caractéristiques de QdS de ces chemins alternatifs composés, ii) une architecture originale appelée SPAD (Super-Peer based Alternate path Discovery), qui permet la découverte et la sélection de manière distribuée de ces chemins alternatifs. SPAD est un système complètement décentralisé, qui peut être facilement et incrémentalement déployé sur l'Internet actuel. Il permet aux utilisateurs situés à la périphérie du réseau de découvrir et d'utiliser directement des chemins alternatifs. ABSTRACT : The convergence of recent technology advances opens the way to new ubiquitous environments, where network-enabled devices collectively form invisible pervasive computing and networking environments around the users. These users increasingly require extensive applications and capabilities from these devices. Recent approaches propose that cooperating service providers, at the edge of the network, offer these required capabilities (i.e services), instead of having them directly provided by the devices. Thus, the network evolves from a plain communication medium into an endless source of services. Such a service, namely an overlay application, is composed of multiple distributed application elements, which cooperate via a dynamic communication mesh, namely an overlay association. The Quality of Service (QoS) perceived by the users of an overlay application greatly depends on the QoS on the communication paths of the corresponding overlay association. This thesis asserts and shows that it is possible to provide QoS to an overlay application by using alternate Internet paths resulting from the compositions of independent consecutive paths. Moreover, this thesis also demonstrates that it is possible to discover, select and compose these independent paths in a distributed manner within an community comprising a limited large number of autonomous cooperating peers, such as the fore-mentioned service providers. Thus, the main contributions of this thesis are i) a comprehensive description and QoS characteristic analysis of these composite alternate paths, and ii) an original architecture, termed SPAD (Super-Peer based Alternate path Discovery), which allows the discovery and selection of these alternate paths in a distributed manner. SPAD is a fully distributed system with no single point of failure, which can be easily and incrementally deployed on the current Internet. It empowers the end-users at the edge of the network, allowing them to directly discover and utilize alternate paths