Current complex service systems are usually comprised of many other components which are often external services performing particular tasks. The quality of service (QoS) attributes such as availability, cost, response time are essential to determine usability and eciency of such system. Obviously, the QoS of such compound system is dependent on the QoS of its components. However, the QoS of each component is naturally unstable and di erent each time it is called due to many factors like network bandwidth, workload, hardware resource, etc. This will consequently make the QoS of the whole system be unstable. This uncertainty can be described and represented with probability distributions. This thesis presents an approach to calculate the QoS of the system when the probability distributions of QoS of each component are provided by service provider or derived from historical data, along with the structure of their compositions. In addition, an analyzer tool is implemented in order to predict the QoS of the given compositions and probability distributions following the proposed approach. The output of the analyzer can be used to predict the behavior of the system to be implemented and to make decisions based on the expected performance. The experimental evaluation shows that the estimation is reliable with a minimal and acceptable error measurement.

Over the years, information technology has created opportunities to improve and extend businesses and to start conducting business in new ways. With the evolution of IT, all businesses and industries are becoming increasingly digitized. This process, or coevolution, of IT and business coming together is called digital transformation. One of the recent trends in this digital transformation is the use of application programmable interfaces (APIs). APIs are standardized digital communication interfaces, used for communication and exchange of information between systems, services and devices (such as computers, smartphones and connected machines). API communication is one of the foundational building blocks in recent disruptive technology trends such as mobile and cloud computing. The purpose of this study is to gain an understanding of the business impact that is created in digital transformation related to the use of APIs. To investigate this novel area, an exploratory study is performed where a frame of reference with an exploratory framework is created based on established academic literature. The exploratory framework consists of three main parts which cover the research questions, including Business Drivers, Business Model Change & Innovation and Challenges & Limitations related to API-enabled digital transformation. The framework is used to gather empirical data consisting of two types, interviews (primary data) and contemporary reports (secondary data). Interviews are performed with API-utilizing companies, consulting firms and IT solution providers and contemporary reports are published by consulting and technology research and advisory firms. Two main business drivers are identified in the study. The first is Understanding & Satisfying Customer Needs which is derived from companies experiencing stronger and changing demands for automated, personalized value-adding services. This requires higher degree of integration across channels and organizations. The second driver is Business Agility, which derives from higher requirements on adapting to changing environments while maintaining operational efficiency. Cost Reduction is also mentioned as a third and secondary driver, as a positive side-effect in combination with the other drivers. The identified impact on business models is that business model innovation is mostly happening in the front-end of business model towards customers. Several examples also exist of purely API-enabled businesses that sell services or manage information exchanges over APIs. The challenges and limitations identified are mostly classic challenges of using IT in businesses and not specific to use of APIs, where the general consensus is that IT and business need to become more integrated, and that strategy and governance for API-initiatives need to be established.

Abstract This thesis introduces a novel Web service-centric solution to pervasive computing, called Service-oriented Pervasive Computing (also called Pervasive Service Computing), which enables computer systems to deal with context in the user’s environment, to dynamically discover and compose existing services, and to develop Internet-scale multimedia applications that support users’ activities. First, this thesis introduces the concept of Pervasive Service Computing and its relation to community coordinated multimedia, context awareness, and service-oriented computing. It then investigates the state of the art, the practices, and techniques which have been developed to support such services. Building on these tools, this study adopts a service-oriented methodology to design a reference model for Pervasive Service Computing, for accommodating specified technical requirements. This model can serve as a guide for research and development towards Pervasive Service Computing. Second, the thesis examines the nature of community coordinated multimedia, and develops the concept of Community Coordinated Multimedia (CCM). To discover the potentials of discoverability and composability of multimedia applications, the thesis introduces a model for Service-oriented Community Coordinated Multimedia (SCCM), and demonstrates the idea of “multimedia application as a service.” Furthermore, the thesis presents a content annotation service and evaluates its feasibility as an end-user prototype. Third, the thesis investigates the nature of context awareness in Pervasive Service Computing, to broaden the definition of context and context-awareness. This research introduces context-aware pervasive service composition (CAPSC) applications, and specifies three-levels of context awareness. Building on this framework, the context-aware service composition prototype is implemented. Fourth, the author examines the overall potential of service composition in Pervasive Service Computing, distinguishes its two main functions as service collaboration, and service coordination, and then develops an ODPSC (Ontology-Driven Pervasive Service Composition) ontology. To address the availability and scalability of service composition, the thesis introduces options for dynamic service composition in the Cloud, and develops an accelerated Cloud architecture for service composition in the Cloud (namely CM4SC middleware). Last, the CM4SC middleware as a service prototype is implemented. / Tiivistelmä Tässä työssä käsitellään uutta jokapaikan tietotekniikan Web-palvelukeskeistä ratkaisua, palveluorientoitunutta jokapaikan tietotekniikkaa (Pervasive Service Computing). Tämän avulla tietokonejärjestelmät voivat ottaa huomioon käyttäjän ympäristön tilanteen, löytää ja koota palveluja dynaamisesti, ja näin voidaan kehittää Internetin laajuisia käyttäjän toimintoja tukevia multimediasovelluksia. Ensiksi työssä esitellään jokapaikan tietotekniikan palvelujen käsite sekä tällaisten palveluiden suhde yhteisöllisesti koordinoituun multimediaan, tilannetietoisuuten ja palveluorientoituneeseen tietotekniikkaan. Tieteen nykytila sekä tällaisia palveluja tukemaan kehitetyt käytännöt ja tekniikat esitellään. Näihin työkaluihin pohjautuen työssä omaksutaan palveluorientoitunut metodiikka, kun jokapaikan tietotekniikan palveluille suunnitellaan referenssimalli, jonka avulla voidaan määritellä teknisiä vaatimuksia ja joka voi muutenkin toimia ohjenuorana jokapaikan tietotekniikan palvelujen tutkimukselle ja tuotekehitykselle. Toiseksi työssä tutkitaan yhteisöllisesti koordinoidun multimedian ominaispiirteitä ja määritellään yhteisöllisesti koordinoidun multimedian (Community Coordinated Multimedia, CCM) käsite. Multimediasovellusten löydettävyyden ja kokoamisen mahdollisuuksien kartoittamiseen luodaan palveluorientoitunut CCM-malli (Service-oriented Community Coordinated Multimedia, SCCM). Työssä esitellään ”multimediasovellus palveluna” -idea, jonka käyttökelpoisuutta arvioidaan sisältöpohjaisen annotoinnin prototyyppiratkaisun avulla. Kolmanneksi työssä tutkitaan jokapaikan tietotekniikan palvelujen tilannetietoisuutta laajentamalla tilanteen ja tilannetietoisuuden määritelmiä. Tutkimus esittelee tilannetietoiseen jokapaikan tietotekniikan palvelujen kokoamiseen (Context-Aware Pervasive Service Composition, CAPSC) perustuvia sovelluksia ja määrittelee kolme tasoa tilannetietoisuudelle. Tämän viitekehyksen avulla toteutetaan tilannetietoinen palvelujen kokoamisen prototyyppi. Neljänneksi työssä arvioidaan jokapaikan tietotekniikan palvelujen kokoamisen mahdollisuuksia, tunnistetaan sen kaksi keskeistä toiminnallisuutta, palvelujen yhteistoiminnallisuus (service collaboration) ja palvelujen koordinointi (service coordination), sekä kehitetään ODPSC (Ontology-Driven Pervasive Service Composition) -ontologia. Työssä esitetään saavutettavuuden ja laajennettavuuden haasteisiin ratkaisuksi dynaaminen palvelujen kokoaminen pilvipalveluna. Työssä kehitetään kiihdytetty pilviarkkitehtuuri (CM4SC-välikerrosohjelmisto) palvelujen kokoamiseen pilvessä. Lopuksi työssä toteutetaan CM4SC-välikerrosohjelmiston palveluprototyyppi.

[pt] Diversos estudos apontam que desenvolvimento orientado a serviços terá, em alguns anos, grande influência sobre o desenvolvimento de sistemas. Esta dissertação discute o que realmente o desenvolvimento orientado a serviços apresenta como novidade tecnológica, através da discussão de todas suas características consideradas relevantes para construção de uma aplicação baseada no conceito de serviços. Características como reuso caixa-preta, distribuição e suporte a heterogeneidade ambiental, entre outras, são discutidas no intuito de identificar suas vantagens e funcionalidades, e principalmente, sua importância para o desenvolvimento orientado a serviços. É discutido, também, o conceito representado pelo termo serviço, que possui interpretações distintas na indústria e em publicações acadêmicas. São apresentados também alguns frameworks que dão suporte ao desenvolvimento orientado a serviços, como Vinci, Jini e os XML Web Services. Finalmente, é apresentada uma proposta para um novo framework que oferece suporte ao desenvolvimento orientado a serviços, e que tem como diferencial a opção de se basear na extensão da infra-estrutura de um servidor de aplicações J2EE. / [en] Several studies point that service-oriented development will have, in some years, great influence on the development of systems. This work shows what service- oriented development actually presents as technological innovation, through the discussion of all its relevant characteristics for construction of an application based on the concept of services. Characteristics as black-box reuse, distribution and environment heterogeneity support, among others, are discussed in intention to identify its advantages and features, and mainly, its importance for the service-oriented development. It is also discussed the concept represented for the term service, that have distinct interpretations in the industry and academic publications. In addition some frameworks are presented that support derviceoriented Development, such as Vinci, Jini and the XML Web Services. Finally, a proposal for a new framework is presented which offers support for Service- Oriented Development. Unlike the others frameworks previously mentioned, this is based on the extension of J2EE application server infrastructure.

M.Tech. / Service Oriented Architecture has many advantages. For example, organisations can align business with Information Technology, reuse the developed functionality, reduce development and maintain cost for applications. Organisations adopt Service Oriented Architecture with the aim of automating and integrating business processes. However, it has information security vulnerabilities that should be considered. For example, applications exchange information across the Internet, where it can be tampered with. Information security is therefore one of the crucial qualities that need to be satisfied within information systems. This dissertation addresses the issue of information security within Service Oriented Architecture applications. Some organisations rely on Service Oriented Architecture governance tools when securing information in their Service Oriented Architecture environment. However, they may purchase them without investigating whether they include information security. The aim of this dissertation is to analyse whether these tools include information security. Each tool is benchmarked against the five information security services, defined by the ISO 7498/2 document and including identification and authentication, authorisation, confidentiality, integrity and non-repudiation. The dissertation concludes with a table summarising the results. This dissertation offers decision-makers information that can assist them in analysing whether Service Oriented Architecture governance tools includes information security. It also assists organisations to be aware of security vulnerabilities within Service Oriented Architecture applications, and the consequences that may arise if information security measures are ignored.

Even though there are many software development and project management methodologies available, research and practice both show that IT software development projects still fail, and that the quality of software products does not always meet customers' expectations. There might be multiple causes for such failures, but some of these reasons can be seen to influence or create others. Therefore, the larger the project is, the higher its risk of failure, especially if the teams involved work remotely (distributed and outsourced). This increase in project complexity is considered the motivation for this paper. Similarly, there are other factors that can result in a project's failure and customers' dissatisfaction regarding software quality. All such factors identified by research conducted by organizations specializing in this area are analyzed in order to identify a common root of IT project failures. Once the root causes of these failures have been identified and analyzed, the goal of the Interface based software development methodology is to solve them. The solution offered by an Interface based software development methodology is to improve understanding of software requirements and to describe these requirements with interfaces in an object-oriented way. Interface based software development will support and drive development towards service-oriented architecture (SOA) and component-based development (CBD). The goal of interface based software development is to increase software testability and maintainability and to make it more easily feasible to execute various software development processes in parallel.

The work targets the very important part of service oriented architecture -- web services. It is focused at one of its practical implementation, from the Microsoft Corporation, especially in the last two releases of .NET Framework. The main target of this work is comprehensive summary and demonstration of Microsoft web services development. The principles of web services and their base in the .NET Framework are described here. At the beginning of this work the web services are put into the scope of service oriented architecture and their main principles are described. Subsequently the .NET Framework is explained with its main principles and with the comparison to the JAVA technology. This part is finished with the explanation of classic ASMX web services. The main part of this work focuses at detailed description of the theoretical and practical aspects of web services in the Windows Communication Foundation and the Windows Workflow Foundation context. Even the development of Windows Forms application is not left out, because they also have done a large progress and they are often consumers of web services. The options of securing web services in the .NET Framework are shown both theoretically and practically including authentication and authorization. The methods of transactional behavior are shown too. The work also focuses at the orchestration of web services including the explanation of workflows with the deployment example. At the end of the work there is revealed how to guarantee interoperability with other technologies, how to manage web services and how to ensure their versioning.

Le domaine de la recherche en neuroimagerie nécessite de pouvoir partager, réutiliser et comparer les outils de traitement d'images des différents laboratoires. Cependant la tâche de partage de traitement sous forme de services et leur composition sous forme de workflow reste une tâche difficile et trop souvent complexe. Ceci est dû dans la plupart des cas à l'hétérogénéité des services et des plateformes qui diffèrent au niveau de leurs conceptions et de leurs implémentations. Nous travaillons dans le cadre du projet NeuroLOG, une initiative cherchant à construire un système fédéré pour le partage de données et d'outils de traitement dans le domaine de la neuroimagerie. Il adopte une approche ontologique pour assurer la médiation et le partage de ressources entre les différents collaborateurs. Notre travail de thèse vise à compléter la médiation pour assurer le partage et la composition des outils de traitement d'images et à fournir aux utilisateurs spécialistes et non-spécialistes du domaine de la neuroimagerie une plateforme de composition de service ergonomique et facile à utiliser. Nous utilisons pour cela les techniques du web sémantique afin de remédier aux différents problèmes d'interopérabilité et de cohérence de ressources utilisées et produites. La première solution proposée se fonde sur une extension de la plateforme OWL-S. Elle a été adaptée aux différents services web de la plateforme de neuroimagerie. On a déduit que finalement les outils qui ne possèdent pas le format de services web et une description conforme au standard WSDL ne peuvent pas être enchaînés sous forme de workflow. A partir de là, nous avons proposé une autre approche pour effectuer la composition de services de traitement d'images. Elle se se fonde sur un nouveau modèle ontologique de composition de services qui répond aux exigences de la neuroimagerie, qui s'articule bien avec l'ontologie de domaine OntoNeuroLOG et qui pourra remédier aux différents problèmes rencontrés lors de l'élaboration de la première approche. Ce travail a permit de remédier à la fois aux problèmes d'hétérogénéité des descripteurs des services et à l'interopérabilité des services selon les contraintes de la neuroimagerie au sein de la plateforme NeuroLOG. / The field of neuroimaging research requires the ability to share, reuse and compare image processing tools coming from different laboratories. However, sharing treatment as services and composing them as workflows, is usually difficult and a complex task. This is due in most cases to the heterogeneity of services and platforms with regards to their conception and their implementation. We work within the NeuroLOG project, which aims at developing a middleware to federate data repositories and to facilitate the sharing and reuse of processing tools to analyze the shared images. It adopts an ontological approach for data and tools mediation and for sharing resources. This work aims to provide tools mediation to enhance the sharing and composition of image processing tools and provide non-specialist and expert users of neuroimaging field with an ergonomic and easy to use composition platform. We have chosen to use the Semantic Web techniques to address the various problems of resource interoperability and consistency. The first proposed solution is based on an extension of the OWL-S framework. It has been adapted to the various web services of our neuroimaging platform. We finally concluded that services that haven't the WSDL standard as descriptor could not be chained as workflow. So, we have proposed a new approach to compose image processing tools. It is based on a new ontological model for service composition that meets the requirements of the neuroimaging domain and the constraints of our domain ontology OntoNeuroLOG and addresses the various problems encountered in the development of the first approach. This work led to solve the two major problems in the composition of services; the heterogeneity of services descriptors and the interoperability of services according to the constraints within the NeuroLOG platform.

L'Internet des objets (ou IdO) se traduit à l'heure actuelle par l'accroissement du nombre d'objets connectés, c'est-à-dire d'appareils possédant une identité propre et des capacités de calcul et de communication de plus en plus sophistiquées : téléphones, montres, appareils ménagers, etc. Ces objets embarquent un nombre grandissant de capteurs et d'actionneurs leur permettant de mesurer l'environnement et d'agir sur celui-ci, faisant ainsi le lien entre le monde physique et le monde virtuel. Spécifiquement, l'Internet des objets pose plusieurs problèmes, notamment du fait de sa très grande échelle, de sa nature dynamique et de l'hétérogénéité des données et des systèmes qui le composent (appareils puissants/peu puissants, fixes/mobiles, batteries/alimentations continues, etc.). Ces caractéristiques nécessitent des outils et des méthodes idoines pour la réalisation d'applications capables (i) d'extraire des informations utiles depuis les nombreuses sources de données disponibles et (ii) d'interagir aussi bien avec l'environnement, au moyen des actionneurs, qu'avec les utilisateurs, au moyen d'interfaces dédiées. Dans cette optique, nous défendons la thèse suivante : en raison de la nature continue des données (mesures physiques, évènements, etc.) et leur volume, il est important de considérer (i) les flux comme modèle de données de référence de l'Internet des objets et (ii) le traitement continu comme modèle de calcul privilégié pour transformer ces flux. En outre, étant donné les préoccupations croissantes relatives à la consommation énergétique et au respect de la vie privée, il est préférable de laisser les objets agir au plus près des utilisateurs, si possible de manière autonome, au lieu de déléguer systématiquement l'ensemble des tâches à de grandes entités extérieures telles que le cloud. À cette fin, notre principale contribution porte sur la réalisation d'un système distribué de gestion de flux de données pour l'Internet des objets. Nous réexaminons notamment deux aspects clés du génie logiciel et des systèmes distribués : les architectures de services et le déploiement. Ainsi, nous apportons des solutions (i) pour l'accès aux flux de données sous la forme de services et (ii) pour le déploiement automatique des traitements continus en fonction des caractéristiques des appareils. Ces travaux sont concrétisés sous la forme d'un intergiciel, Dioptase, spécifiquement conçu pour être exécuté directement sur les objets et les transformer en fournisseurs génériques de services de calcul et de stockage.Pour valider nos travaux et montrer la faisabilité de notre approche, nous introduisons un prototype de Dioptase dont nous évaluons les performances en pratique. De plus, nous montrons que Dioptase est une solution viable, capable de s'interfacer avec les systèmes antérieurs de capteurs et d'actionneurs déjà déployés dans l'environnement. / The Internet of Things (IoT) is currently characterized by an ever-growing number of networked Things, i.e., devices which have their own identity together with advanced computation and networking capabilities: smartphones, smart watches, smart home appliances, etc. In addition, these Things are being equipped with more and more sensors and actuators that enable them to sense and act on their environment, enabling the physical world to be linked with the virtual world. Specifically, the IoT raises many challenges related to its very large scale and high dynamicity, as well as the great heterogeneity of the data and systems involved (e.g., powerful versus resource-constrained devices, mobile versus fixed devices, continuously-powered versus battery-powered devices, etc.). These challenges require new systems and techniques for developing applications that are able to (i) collect data from the numerous data sources of the IoT and (ii) interact both with the environment using the actuators, and with the users using dedicated GUIs. To this end, we defend the following thesis: given the huge volume of data continuously being produced by sensors (measurements and events), we must consider (i) data streams as the reference data model for the IoT and (ii) continuous processing as the reference computation model for processing these data streams. Moreover, knowing that privacy preservation and energy consumption are increasingly critical concerns, we claim that all the Things should be autonomous and work together in restricted areas as close as possible to the users rather than systematically shifting the computation logic into powerful servers or into the cloud. For this purpose, our main contribution can be summarized as designing and developing a distributed data stream management system for the IoT. In this context, we revisit two fundamental aspects of software engineering and distributed systems: service-oriented architecture and task deployment. We address the problems of (i) accessing data streams through services and (ii) deploying continuous processing tasks automatically, according to the characteristics of both tasks and devices. This research work lead to the development of a middleware layer called Dioptase, designed to run on the Things and abstract them as generic devices that can be dynamically assigned communication, storage and computation tasks according to their available resources. In order to validate the feasability and the relevance of our work, we implemented a prototype of Dioptase and evaluated its performance. In addition, we show that Dioptase is a realistic solution which can work in cooperation with legacy sensor and actuator networks currently deployed in the environment.

This thesis is focused on service in frame of enterprise computing and composition of these services. This brings a number of issues in large spectra of perspectives and this thesis has the ambition these issues resolve. The goal of this thesis is considering the principles application of service oriented architecure and standard methodologies in composition of internally managed by process complex business service, which composes services in SAP information system and which use resources of IBM WebSphere Process Server and IBM WebSphere ESB Server. The basic presumption to goal achieve is precise identification and definition of service. Also important is the notion of composition. So what are especially logical links between services. Based on this service identification it is going to be clarified the options of its composition and it is going to be specified the importance of service definition and composition in enterprise computing area. After defining the services in computing context the thesis is going to be focused on composite business services. Composite business services are going to be analyzed from three perspectives: Engineering, Management and Governance. The benefit of thesis is answer to question if it is possible in specific environment with specific conditions to compose business services, which respect the criterions of three perspectives: Engineering, Management and Governance. If the composition of those business services will respect generally respected standards and recommendations in a defined environment. Thesis in its structure passes from general knowledge about services to knowledge about services in frame of enterprise computing. This knowledge is based on analysis and recommendations of methodologies which are focused on service oriented IT management. Knowledge of this analysis are became basis for definition of three perspectives. Principles defined in three perspectives are going to be verified in real experiment.