Semantic-based middleware solutions to support context-aware service provisioning in pervasive environments

The dynamicity and heterogeneity that characterize pervasive environments raise new challenges in the design of mobile middleware. Pervasive environments are characterized by a significant degree of heterogeneity, variability, and dynamicity that conventional middleware solutions are not able to adequately manage. Originally designed for use in a relatively static context, such middleware systems tend to hide low-level details to provide applications with a transparent view on the underlying execution platform. In mobile environments, however, the context is extremely dynamic and cannot be managed by a priori assumptions. Novel middleware should therefore support mobile computing applications in the task of adapting their behavior to frequent changes in the execution context, that is, it should become context-aware. In particular, this thesis has identified the following key requirements for novel context-aware middleware that existing solutions do not fulfil yet. (i) Middleware solutions should support interoperability between possibly unknown entities by providing expressive representation models that allow to describe interacting entities, their operating conditions and the surrounding world, i.e., their context, according to an unambiguous semantics. (ii) Middleware solutions should support distributed applications in the task of reconfiguring and adapting their behavior/results to ongoing context changes. (iii) Context-aware middleware support should be deployed on heterogeneous devices under variable operating conditions, such as different user needs, application requirements, available connectivity and device computational capabilities, as well as changing environmental conditions. Our main claim is that the adoption of semantic metadata to represent context information and context-dependent adaptation strategies allows to build context-aware middleware suitable for all dynamically available portable devices. Semantic metadata provide powerful knowledge representation means to model even complex context information, and allow to perform automated reasoning to infer additional and/or more complex knowledge from available context data. In addition, we suggest that, by adopting proper configuration and deployment strategies, semantic support features can be provided to differentiated users and devices according to their specific needs and current context. This thesis has investigated novel design guidelines and implementation options for semantic-based context-aware middleware solutions targeted to pervasive environments. These guidelines have been applied to different application areas within pervasive computing that would particularly benefit from the exploitation of context. Common to all applications is the key role of context in enabling mobile users to personalize applications based on their needs and current situation. The main contributions of this thesis are (i) the definition of a metadata model to represent and reason about context, (ii) the definition of a model for the design and development of context-aware middleware based on semantic metadata, (iii) the design of three novel middleware architectures and the development of a prototypal implementation for each of these architectures, and (iv) the proposal of a viable approach to portability issues raised by the adoption of semantic support services in pervasive applications.

Automated service provisioning in programmable network infrastructures

Modern networks are undergoing a fast and drastic evolution, with software taking a more predominant role. Virtualization and cloud-like approaches are replacing physical network appliances, reducing the management burden of the operators. Furthermore, networks now expose programmable interfaces for fast and dynamic control over traffic forwarding. This evolution is backed by standard organizations such as ETSI, 3GPP, and IETF. This thesis will describe which are the main trends in this evolution. Then, it will present solutions developed during the three years of Ph.D. to exploit the capabilities these new technologies offer and to study their possible limitations to push further the state-of-the-art. Namely, it will deal with programmable network infrastructure, introducing the concept of Service Function Chaining (SFC) and presenting two possible solutions, one with Openstack and OpenFlow and the other using Segment Routing and IPv6. Then, it will continue with network service provisioning, presenting concepts from Network Function Virtualization (NFV) and Multi-access Edge Computing (MEC). These concepts will be applied to network slicing for mission-critical communications and Industrial IoT (IIoT). Finally, it will deal with network abstraction, with a focus on Intent Based Networking (IBN). To summarize, the thesis will include solutions for data plane programming with evaluation on well-known platforms, performance metrics on virtual resource allocations, novel practical application of network slicing on mission-critical communications, an architectural proposal and its implementation for edge technologies in Industrial IoT scenarios, and a formal definition of intent using a category theory approach.

An investigation into system security requirements and implementation in an Application Service Provider (ASP) environment

Although the ASP model has been around for over a decade, it has not achieved the expected high level of market uptake. This research project examines the past and present state of ASP adoption and identifies security as a primary factor influencing the uptake of the model. The early chapters of this document examine the ASP model and ASP security in particular. Specifically, the literature and technology review chapter analyses ASP literature, security technologies and best practices with respect to system security in general. Based on this investigation, a prototype to illustrate the range and types of technologies that encompass a security framework was developed and is described in detail. The latter chapters of this document evaluate the practical implementation of system security in an ASP environment. Finally, this document outlines the research outputs, including the conclusions drawn and recommendations with respect to system security in an ASP environment. The primary research output is the recommendation that by following best practices with respect to security, an ASP application can provide the same level of security one would expect from any other n-tier client-server application. In addition, a security evaluation matrix, which could be used to evaluate not only the security of ASP applications but the security of any n-tier application, was developed by the author. This thesis shows that perceptions with regard to fears of inadequate security of ASP solutions and solution data are misguided. Finally, based on the research conducted, the author recommends that ASP solutions should be developed and deployed on tried, tested and trusted infrastructure. Existing Application Programming Interfaces (APIs) should be used where possible and security best practices should be adhered to where feasible.

Service Quality of ASPs (Application Service Providers): Case of an E-accounting Service

Service quality has been a hot topic in services marketing research since the ‘80s. Although it has been widely researched in the B2C context, as well as there is some research in the B2B side, it has received very little attention specifically in the context of the ASP (Application Service Provider) business model. The thesis uses streams of service quality literature in B2C and B2B as well as research of the ASP model to form a comprehensive understanding of service quality in the context of the ASPs. The empirical part consists of a case study of Netvisor, a fast-growing Finnish ASP providing e-accounting services. The key findings are that some traditional service quality dimensions seem to apply also in the ASP context and the relative importance of some dimensions differs with regard to different customer levels. Suggestions are made to improve the service quality of the case company.

ASP-ohjelmiston kehittäminen kansainvälisille markkinoille

ASP eli sovellusvuokraus on jatkuvasti yleistyvä vaihtoehto perinteiselle ohjelmistojen ostamiselle. Suomessa on pieniä ASP-toimittajia joilla voisi olla mahdollisuuksia pärjätä kansainvälisillä markkinoilla, mutta kansainvälistyminen tuo haasteita kaupallisesti sekä myös teknisesti. Työn tavoitteena on suunnitella ASP-ohjelmiston kehittämistä kansainväliseen käyttöön sopivaksi sekä tarkastella myös laajemmin ASP-ohjelmiston vientiä koskevia kysymyksiä. Erityisesti kainsainvälistymiseen liittyvien aiheiden lisäksi työssä esitellään myös ASP-toimintamalli, kehityksen kohteena oleva Severa Oy:n ASP-palvelu sekä ASP-sovelluksen kehittämiseen käytettäviä tekniikoita ja työkaluja niin WWW-sovelluskehityksen kuin tietokantojenkin osalta.

ASP-sovellusvuokraus taloushallinnossa

Tämä kandidaatintyö käsittelee ASP-sovellusvuokrausta ja sen käyttöä taloushallinnon ulkoistamisratkaisuna. Tarkastelu on tehty sovellusvuokrausasiakkaina toimivien pk-yritysten näkökulmasta. ASP-sovellusvuokraus tarkoittaa sovelluksen ja tämän oheispalveluiden käyttöä yhden tai useamman ASP-palveluntarjoajan tuottamana tämän palvelimelta erilaisten tietoverkkojen välityksellä. Työssä esitellään sovellusvuokrauksen käsite, sen kustannukset, mahdollisuudet, käyttöönottoprosessi ja riskit. Toisena osa-alueena on käsitelty sovellusvuokrausta taloushallinnon näkökulmasta sekä yleisesti taloushallinnon ulkoistamista. Tarkasteltuja osa-alueita ovat sopimukset, sähköinen taloushallinto ja lyhyesti toiminnanohjausjärjestelmät. Kolmen caseesimerkin avulla on valotettu taloushallinnon ulkoistamisratkaisua käytännössä. Työn tuloksena todetaan, että sovellusvuokraus on toimiva taloushallinnon ulkoistamisratkaisu niin ohjelmistojen kuin toiminnanohjausjärjestelmienkin näkökulmasta, kunhan riskit huomioidaan ja päätöksentekoprosessi on huolellinen. Toisaalta ASP-mallia tulisi kehittää erityisesti pk-yrityksille ystävällisemmäksi. Tulevaisuudessa taloushallinnon sovellusvuokraus ja ulkoistaminen tulee tarkoittamaan ASP-mallin laajentumista ulkoistettujen palveluiden käyttöön verkon välityksellä.

ASP-palvelut tuotanto- ja teollisuusyrityksille

Tämä kandidaatintyö käsittelee sovellusvuokrausta sekä tuotanto- ja teollisuusyrityksille suunnattuja sähköisiä palveluita, joita on mahdollista hankkia myös ASP-mallin mukaisesti. Sovellusvuokraus tarkoittaa toimintamallia, jossa asiakas käyttää ohjelmistoja tietoverkon välityksellä palveluntarjoajan palvelimilla. Käytöstä maksetaan vuokrahinnoittelun mukaan. Työssä käydään läpi sovellusvuokraus, sen hyödyt, riskit, käyttöönotto sekä sovellusvuokraussopi-muksen sisältö. Tuotanto- ja teollisuusyrityksille suunnattuja sähköisiä palveluita ovat yrityksen toiminnan ohjaukseen liittyvät järjestelmät kuten toimitusketjun hallinta, toiminnanohjausjärjestelmä, valmistuksen ohjaus, asiakkuuden hallinta, tuotetiedon hallinta ja henkilöstöjohtaminen. ASP-palveluna voidaan myös toteuttaa sähköisiä kauppapaikkoja. Kolme case-esimerkkiä valottavat palveluiden toimintaa käytännössä. Työn tuloksena todetaan, että sovellusvuokrauspalveluiden tarjonta sekä myös käyttö on lisääntynyt huimasti. Tuotanto- ja teollisuusyrityksille suunnatuista sähköisistä palveluista suurinta osaa on mahdollista saada myös ASP-mallin mukaisesti. Sovellusvuokraus on varteenotettava vaihtoehto uusittaessa tuotanto- tai teollisuusyritysten tietojärjestelmiä, mutta myös riskit tulee arvioida tarkkaan.

A framework for monitoring and runtime recovery of web service-based applications

Service provisioning is a challenging research area for the design and implementation of autonomic service-oriented software systems. It includes automated QoS management for such systems and their applications. Monitoring, Diagnosis and Repair are three key features of QoS management. This work presents a self-healing Web service-based framework that manages QoS degradation at runtime. Our approach is based on proxies. Proxies act on meta-level communications and extend the HTTP envelope of the exchanged messages with QoS-related parameter values. QoS Data are filtered over time and analysed using statistical functions and the Hidden Markov Model. Detected QoS degradations are handled with proxies. We experienced our framework using an orchestrated electronic shop application (FoodShop).

A load-balancing spare capacity reallocation approach in service-rich SONET metro mesh networks

The next-generation SONET metro network is evolving into a service-rich infrastructure. At the edge of such a network, multi-service provisioning platforms (MSPPs) provide efficient data mapping enabled by Generic Framing Procedure (GFP) and Virtual Concatenation (VC). The core of the network tends to be a meshed architecture equipped with Multi-Service Switches (MSSs). In the context of these emerging technologies, we propose a load-balancing spare capacity reallocation approach to improve network utilization in the next-generation SONET metro networks. Using our approach, carriers can postpone network upgrades, resulting in increased revenue with reduced capital expenditures (CAPEX). For the first time, we consider the spare capacity reallocation problem from a capacity upgrade and network planning perspective. Our approach can operate in the context of shared-path protection (with backup multiplexing) because it reallocates spare capacity without disrupting working services. Unlike previous spare capacity reallocation approaches which aim at minimizing total spare capacity, our load-balancing approach minimizes the network load vector (NLV), which is a novel metric that reflects the network load distribution. Because NLV takes into consideration both uniform and non-uniform link capacity distribution, our approach can benefit both uniform and non-uniform networks. We develop a greedy loadbalancing spare capacity reallocation (GLB-SCR) heuristic algorithm to implement this approach. Our experimental results show that GLB-SCR outperforms a previously proposed algorithm (SSR) in terms of established connection capacity and total network capacity in both uniform and non-uniform networks.

A survey on service quality description

Quality of service (QoS) can be a critical element for achieving the business goals of a service provider, for the acceptance of a service by the user, or for guaranteeing service characteristics in a composition of services, where a service is defined as either a software or a software-support (i.e., infrastructural) service which is available on any type of network or electronic channel. The goal of this article is to compare the approaches to QoS description in the literature, where several models and metamodels are included. consider a large spectrum of models and metamodels to describe service quality, ranging from ontological approaches to define quality measures, metrics, and dimensions, to metamodels enabling the specification of quality-based service requirements and capabilities as well as of SLAs (Service-Level Agreements) and SLA templates for service provisioning. Our survey is performed by inspecting the characteristics of the available approaches to reveal which are the consolidated ones and which are the ones specific to given aspects and to analyze where the need for further research and investigation lies. The approaches here illustrated have been selected based on a systematic review of conference proceedings and journals spanning various research areas in computer science and engineering, including: distributed, information, and telecommunication systems, networks and security, and service-oriented and grid computing.

Dynamic adaptation of stability periods for service level agreements

A QoS adaptation to dynamically changing system conditions that takes into consideration the user’s constraints on the stability of service provisioning is presented. The goal is to allow the system to make QoS adaptation decisions in response to fluctuations in task traffic flow, under the control of the user. We pay special attention to the case where monitoring the stability period and resource load variation of Service Level Agreements for different types of services is used to dynamically adapt future stability periods, according to a feedback control scheme. System’s adaptation behaviour can be configured according to a desired confidence level on future resource usage. The viability of the proposed approach is validated by preliminary experiments.

Real-time Quality of Service Controller for Differentiated Services

IP-verkkojen hyvin tunnettu haitta on, että nämä eivät pysty takaamaan tiettyä palvelunlaatua (Quality of Service) lähetetyille paketeille. Seuraavat kaksi tekniikkaa pidetään lupaavimpina palvelunlaadun tarjoamiselle: Differentiated Services (DiffServ) ja palvelunlaatureititys (QoS Routing). DiffServ on varsin uusi IETF:n määrittelemä Internetille tarkoitettu palvelunlaatumekanismi. DiffServ tarjoaa skaalattavaa palvelujen erilaistamista ilman viestintää joka hypyssä ja per-flow –tilan ohjausta. DiffServ on hyvä esimerkki hajautetusta verkkosuunnittelusta. Tämän palvelutasomekanismin tavoite on viestintäjärjestelmien suunnittelun yksinkertaistaminen. Verkkosolmu voidaan rakentaa pienestä hyvin määritellystä rakennuspalikoiden joukosta. Palvelunlaatureititys on reititysmekanismi, jolla liikennereittejä määritellään verkon käytettävissä olevien resurssien pohjalta. Tässä työssä selvitetään uusi palvelunlaatureititystapa, jota kutsutaan yksinkertaiseksi monitiereititykseksi (Simple Multipath Routing). Tämän työn tarkoitus on suunnitella palvelunlaatuohjain DiffServille. Tässä työssä ehdotettu palvelunlaatuohjain on pyrkimys yhdistää DiffServ ja palvelunlaatureititysmekanismeja. Työn kokeellinen osuus keskittyy erityisesti palvelunlaatureititysalgoritmeihin.