Software Architecture Patterns for a Context-Processing Middleware Framework

International audienceUbiquitous applications are characterised by variations of their execution context. Their correct operation requires some continual adaptations based on the observation of their execution context. The design and the implementation of these observation policies is then the cornerstone of any ubiquitous applications. In this article, we propose COSMOS which is a framework for the principled specification and composition of context observation policies. With COSMOS, these policies are decomposed into fine-grained units called \emph{context nodes} implemented as software components. These units perform basic context-related operations (\emph{e.g.}, gathering data from a system or network probe, computing threshold or average values) and are assembled with a set of well-identified architectural design patterns. In this article, COSMOS is motivated and illustrated with an example from the domain of mobile e-commerce applications

Towards dynamic context discovery and composition

Context-awareness has been identified as a key characteristic for pervasive computing systems. As a variety of context-aware environments begin to flourish, pervasive applications shall have to interact different environments well. In this paper we propose extensions to the Strathclyde Context Infrastructure that gives context-aware applications the potential to adapt to unfamiliar environments transparently. We present a vision of a context discovery technique based on automated semantic reasoning about context information and services. The technique will offer higher levels of scalability and of interoperability with new context environments that cannot be achieved with current methods

Real-time επεξεργασία για Big Data Location-based Services και υλοποίηση στο Apache Storm

Η διπλωματική εργασία αυτή εκπονήθηκε με σκοπό την προσέγγιση και την υλοποίηση μιας αναλυτικής λογικής για την real time επεξεργασία δεδομένων σε indoor (και όχι μόνο) δίκτυα αισθητήρων. Αρχικά ορίζονται και αναλύονται οι αρχές και τα βασικότερα δομικά στοιχεία των υπηρεσιών τοποθεσίας (location-based services). Συγκεκριμένα αναλύονται οι επικρατέστερες τεχνολογίες στον κλάδο και τα θεμέλια στοιχεία τους, δηλαδή το middleware, τα network components καθώς και οι επιμέρους παράγοντες. Γίνεται αναφορά στα στοιχεία και στα κριτήρια πάνω στα οποία θα υλοποιηθεί έπειτα ο κώδικας επεξεργασίας στο ορισμένο περιβάλλον λειτουργίας (Apache Storm). Έπειτα αναλύεται το stream processing ως βασικό στοιχείο για την παράλληλη επεξεργασία μιας συγκεκριμένης μορφής πληροφορίας, η οποία δεν απαιτεί περαιτέρω συμφωνία και παράλληλες ρυθμίσεις από τους κόμβους τους οποίους συνδέει. Αναφέρονται τα χαρακτηριστά που πρέπει να πληρούνται από τις εφαρμογές ώστε να μπορούν να χρησιμοποιούν κατάλληλα stream processing. Εν συνεχεία αναλύονται οι contextors ως βασικός μηχανισμός αφαιρετικής διανομής της πληροφορίας. Συγκεκριμενοποιώντας το stream processing στην εν λόγω διπλωματική γίνεται αναφορά και στα real time processing συστήματα ως προς τις stream processing λογικές που χρησιμοποιούν. Τέλος, γίνεται αναλυτική αναφορά στον κώδικα υλοποίησης της business logic για indoor positioning συστήματα που υλοποιήθηκε στο Apache Storm και σε γλώσσα προγραμματισμού Java.This master thesis was developed in order to approach and implement a detailed logic for real-time data processing in indoor (and not only) sensor networks. The principles and the basic building blocks of location-based services are defined and analyzed. Specifically, we analyze the prevalent technologies in the industry and the foundation elements, namely the middleware (and its construction principles), the network components and othere individual factors. A detailed reference is been made to the criteria on which we will then produce the source code in the specific operating environment we chose to work (Apache Storm). Then we proceed to the analysis of the stream processing as a key element for the parallel processing of a particular kind of information, which requires no further agreement (on software and configurations) or parallel arrangents of the nodes which connects. The characteristics that need to be fulfilled by the applications are reported as well in order to give a clear image of appropriate stream processing implementation. Then we analyze contextors as a key mechanism of deductive distribution of information. Furthermore, we specify the stream processing based systems in comparison with real-time processing systems. Finally, there is a detailed report of the implementation of business logic and of the source code itself. The system of implementation was Apache Storm and Java programming language

Distributed reservoir sampling algorithms for data pre-processing with use of Kafka Streams

Με την ανάπτυξη του IoT και με τον αριθμό των συσκευών που αναμένεται να συνδεθούν σε αυτό να ξεπερνάει τα 30 δισεκατομμύρια μέχρι το 2020 καθώς και με την συνεπακόλουθη αύξηση στα δεδομένα που μεταδίδονται κρίνεται αναγκαίο από τα σύγχρονα συστήματα επεξεργασίας δεδομένων μεγάλης κλίμακας να χρησιμοποιούν αποδοτικούς αλγορίθμους σε συνδυασμό με προγραμματιστικές βιβλιοθήκες που χρησιμοποιούνται ευρέως στον τομέα της βιομηχανίας. Σκοπός της διπλωματικής εργασίας είναι η ανάλυση και παρουσίαση αλγορίθμων αποθέματος καθώς και η ανάπτυξη τους με την χρήση της βιβλιοθήκης Kafka Streams με σκοπό την επίλυση του προβλήματος της κατανομής τους. Αξιοποιώντας τις ιδιαιτερότητες της βιβλιοθήκης και των αλγορίθμων στοχεύουμε στην υλοποίηση ενός εργαλείου που βοηθάει αναλυτές και πειραματιστές στο τομέα του ΙοΤ στην προεπεξεργασία των δεδομένων και την ταχεία λήψη αποτελεσμάτων από μια συνεχόμενη ροή δεδομένων.With the rapid growth of the Internet of Things (IoT) and with the number of devices expected to connect to it estimated to exceed 30 billion by 2020 and the consequent increase in data transmitted, it is necessary for big data processing systems to use efficient algorithms in combination with programming libraries that are widely used in the industry. This master thesis aims to analyze and present reservoir sampling algorithms as well as to develop them using the Kafka Streams API in order to solve the problem of their distribution. By taking advantage of the API and the algorithm specific characteristics, we aim to implement a tool that helps analysts and experimenters on the IoT field to preprocess data and quickly obtain results from a continuous data stream

Towards ad-hoc situation determination

Toolkits such as PlaceLab [1] have been successful in making location information freely available for use in experimental ubiquitous computing applications. As users' expectations of ubiquitous computing applications grow, we envisage a need for tools that can deliver a much richer set of contextual information. The high-level situation of the current environment is a key contextual element, and this position paper focuses on a method to provide this information for an ad-hoc group of people and devices. The contributions of this paper are i) a demonstration of how information retrieval (IR) techniques can be applied to situation determination in context-aware systems, ii) a proposal of a novel approach to situation determination that combines these adapted IR techniques with a process of cooperative interaction, and iii) a report of preliminary results. The approach offers a high level of utility and accuracy, with a greater level of automation than other contemporary approaches

Active architecture for pervasive contextual services

International Workshop on Middleware for Pervasive and Ad-hoc Computing MPAC 2003), ACM/IFIP/USENIX International Middleware Conference (Middleware 2003), Rio de Janeiro, Brazil This work was supported by the FP5 Gloss project IST2000-26070, with partners at Trinity College Dublin and Université Joseph Fourier, and by EPSRC grants GR/M78403/GR/M76225, Supporting Internet Computation in Arbitrary Geographical Locations, and GR/R45154, Bulk Storage of XML Documents.Pervasive services may be defined as services that are available "to any client (anytime, anywhere)". Here we focus on the software and network infrastructure required to support pervasive contextual services operating over a wide area. One of the key requirements is a matching service capable of as-similating and filtering information from various sources and determining matches relevant to those services. We consider some of the challenges in engineering a globally distributed matching service that is scalable, manageable, and able to evolve incrementally as usage patterns, data formats, services, network topologies and deployment technologies change. We outline an approach based on the use of a peer-to-peer architecture to distribute user events and data, and to support the deployment and evolution of the infrastructure itself.Peer reviewe

The Smart Stage: Designing 3D interaction metaphors for immersive and ubiquitous music systems

This conceptual paper describes a work in progress in the process of design and implementation of the Smart Stage, an interactive music system prototype for collaborative musical creativity in immersive and ubiquitous environments. This system is intended to have a low entry barrier, thus more forgiving to users with lesser experience or knowledge in music, and it is designed with affordances to support intuitive progress in improvisational performance in a collaborative setting. We present a preliminary technical overview of the system and a first case study of a 3D interaction metaphor for granular synthesis, developed for this environment.Innovation Agency (Agência de Inovação, ADI, Portugal) and Quadro de Referência Estratégico Nacional (QREN, Portugal): VisualYzARt: Visual programming framework for augmented reality and ubiquitous natural user interfaces (QREN-ADI ref: 23201) and COMPETE - Programa Operacional Factores de Competitividade (POFC

Display-centred applications in ubiquitous computing

Public displays can play an important enabling role in ubiquitous computing environments. This paper describes an on-going work for a multipurpose, multi-display infrastructure, designed to address the requirements of display-centred applications in ubiquitous computing environments. The system provides an infrastructure in which situated displays can act as portals to the physical space, allowing ubicomp applications to support their association with the physical world by providing them with display services and situationspecific user input and context information

Active architecture for pervasive contextual services

Pervasive services may be defined as services that are available to any client (anytime, anywhere). Here we focus on the software and network infrastructure required to support pervasive contextual services operating over a wide area. One of the key requirements is a matching service capable of assimilating and filtering information from various sources and determining matches relevant to those services. We consider some of the challenges in engineering a globally distributed matching service that is scalable, manageable, and able to evolve incrementally as usage patterns, data formats, services, network topologies and deployment technologies change. We outline an approach based on the use of a peer-to-peer architecture to distribute user events and data, and to support the deployment and evolution of the infrastructure itself