Reasoning the FMA ontologies with TrOWL

Publisher PD

GECAF : a generic and extensible framework for developing context-aware smart environments

The new pervasive and context-aware computing models have resulted in the development of modern environments which are responsive to the changing needs of the people who live, work or socialise in them. These are called smart envirnments and they employ high degree of intelligence to consume and process information in order to provide services to users in accordance with their current needs. To achieve this level of intelligence, such environments collect, store, represent and interpret a vast amount of information which describes the current context of their users. Since context-aware systems differ in the way they interact with users and interpret the context of their entities and the actions they need to take, each individual system is developed in its own way with no common architecture. This fact makes the development of every context aware system a challenge. To address this issue, a new and generic framework has been developed which is based on the Pipe-and-Filter software architectural style, and can be applied to many systems. This framework uses a number of independent components that represent the usual functions of any context-aware system. These components can be configured in different arrangements to suit the various systems' requirements. The framework and architecture use a model to represent raw context information as a function of context primitives, referred to as Who, When, Where, What and How (4W1H). Historical context information is also defined and added to the model to predict some actions in the system. The framework uses XML code to represent the model and describes the sequence in which context information is being processed by the architecture's components (or filters). Moreover, a mechanism for describing interpretation rules for the purpose of context reasoning is proposed and implemented. A set of guidelines is provided for both the deployment and rule languages to help application developers in constructing and customising their own systems using various components of the new framework. To test and demonstrate the functionality of the generic architecture, a smart classroom environment has been adopted as a case study. An evaluation of the new framework has also been conducted using two methods: quantitative and case study driven evaluation. The quantitative method used information obtained from reviewing the literature which is then analysed and compared with the new framework in order to verify the completeness of the framework's components for different xiisituations. On the other hand, in the case study method the new framework has been applied in the implementation of different scenarios of well known systems. This method is used for verifying the applicability and generic nature of the framework. As an outcome, the framework is proven to be extensible with high degree of reusability and adaptability, and can be used to develop various context-aware systems.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Traceability of Requirements and Software Architecture for Change Management

At the present day, software systems get more and more complex. The requirements of software systems change continuously and new requirements emerge frequently. New and/or modified requirements are integrated with the existing ones, and adaptations to the architecture and source code of the system are made. The process of integration of the new/modified requirements and adaptations to the software system is called change management. The size and complexity of software systems make change management costly and time consuming. To reduce the cost of changes, it is important to apply change management as early as possible in the software development cycle. Requirements traceability is considered crucial in change management for establishing and maintaining consistency between software development artifacts. It is the ability to link requirements back to stakeholders’ rationales and forward to corresponding design artifacts, code, and test cases. When changes for the requirements of the software system are proposed, the impact of these changes on other requirements, design elements and source code should be traced in order to determine parts of the software system to be changed. Determining the impact of changes on the parts of development artifacts is called change impact analysis. Change impact analysis is applicable to many development artifacts like requirements documents, detailed design, source code and test cases. Our focus is change impact analysis in requirements and software architecture. The need for change impact analysis is observed in both requirements and software architecture. When a change is introduced to a requirement, the requirements engineer needs to find out if any other requirement related to the changed requirement is impacted. After determining the impacted requirements, the software architect needs to identify the impacted architectural elements by tracing the changed requirements to software architecture. It is hard, expensive and error prone to manually trace impacted requirements and architectural elements from the changed requirements. There are tools and approaches that automate change impact analysis like IBM Rational RequisitePro and DOORS. In most of these tools, traces are just simple relations and their semantics is not considered. Due to the lack of semantics of traces in these tools, all requirements and architectural elements directly or indirectly traced from the changed requirement are candidate impacted. The requirements engineer has to inspect all these candidate impacted requirements and architectural elements to identify changes if there are any. In this thesis we address the following problems which arise in performing change impact analysis for requirements and software architecture. Explosion of impacts in requirements after a change in requirements. In practice, requirements documents are often textual artifacts with implicit structure. Most of the relations among requirements are not given explicitly. There is a lack of precise definition of relations among requirements in most tools and approaches. Due to the lack of semantics of requirements relations, change impact analysis may produce high number of false positive and false negative impacted requirements. A requirements engineer may have to analyze all requirements in the requirements document for a single change. This may result in neglecting the actual impact of a change. Manual, expensive and error prone trace establishment. Considerable research has been devoted to relating requirements and design artifacts with source code. Less attention has been paid to relating Requirements (R) with Architecture (A) by using well-defined semantics of traces. Designing architecture based on requirements is a problem solving process that relies on human experience and creativity, and is mainly manual. The software architect may need to manually assign traces between R&A. Manual trace assignment is time-consuming, expensive and error prone. The assigned traces might be incomplete and invalid. Explosion of impacts in software architecture after a change in requirements. Due to the lack of semantics of traces between R&A, change impact analysis may produce high number of false positive and false negative impacted architectural elements. A software architect may have to analyze all architectural elements in the architecture for a single requirements change. In this thesis we propose an approach that reduces the explosion of impacts in R&A. The approach employs semantic information of traces and is supported by tools. We consider that every relation between software development artifacts or between elements in these artifacts can play the role of a trace for a certain traceability purpose like change impact analysis. We choose Model Driven Engineering (MDE) as a solution platform for our approach. MDE provides a uniform treatment of software artifacts (e.g. requirements documents, software design and test documents) as models. It also enables using different formalisms to reason about development artifacts described as models. To give an explicit structure to requirements documents and treat requirements, architecture and traces in a uniform way, we use metamodels and models with formally defined semantics. The thesis provides the following contributions: A modeling language for definition of requirements models with formal semantics. The language is defined according to the MDE principles by defining a metamodel. It is based on a survey about the most commonly found requirements types and relation types. With this language, the requirements engineer can explicitly specify the requirements and the relations among them. The semantics of these entities is given in First Order Logic (FOL) and allows two activities. First, new relations among requirements can be inferred from the initial set of relations. Second, requirements models can be automatically checked for consistency of the relations. Tool for Requirements Inferencing and Consistency Checking (TRIC) is developed to support both activities. The defined semantics is used in a technique for change impact analysis in requirements models. A change impact analysis technique for requirements using semantics of requirements relations and requirements change types. The technique aims at solving the problem of explosion of impacts in requirements when semantics of requirements relations is missing. The technique uses formal semantics of requirements relations and requirements change types. A classification of requirements changes based on the structure of a textual requirement is given and formalized. The semantics of requirements change types is based on FOL. We support three activities for impact analysis. First, the requirements engineer proposes changes according to the change classification before implementing the actual changes. Second, the requirements engineer indentifies the propagation of the changes to related requirements. The change alternatives in the propagation are determined based on the semantics of change types and requirements relations. Third, possible contradicting changes are identified. We extend TRIC with a support for these activities. The tool automatically determines the change propagation paths, checks the consistency of the changes, and suggests alternatives for implementing the change. A technique that provides trace establishment between R&A by using architecture verification and semantics of traces. It is hard, expensive and error prone to manually establish traces between R&A. We present an approach that provides trace establishment by using architecture verification together with semantics of requirements relations and traces. We use a trace metamodel with commonly used trace types. The semantics of traces is formalized in FOL. Software architectures are expressed in the Architecture Analysis and Design Language (AADL). AADL is provided with a formal semantics expressed in Maude. The Maude tool set allows simulation and verification of architectures. The first way to establish traces is to use architecture verification techniques. A given requirement is reformulated as a property in terms of the architecture. The architecture is executed and a state space is produced. This execution simulates the behavior of the system on the architectural level. The property derived from the requirement is checked by the Maude model checker. Traces are generated between the requirement and the architectural components used in the verification of the property. The second way to establish traces is to use the requirements relations together with the semantics of traces. Requirements relations are reflected in the connections among the traced architectural elements based on the semantics of traces. Therefore, new traces are inferred from existing traces by using requirements relations. We use semantics of requirements relations and traces to both generate/validate traces and generate/validate requirements relations. There is a tool support for our approach. The tool provides the following: (1) generation/validation of traces by using requirements relations and/or verification of architecture, (2) generation/validation of requirements relations by using traces. A change impact analysis technique for software architecture using architecture verification and semantics of traces between R&A. The software architect needs to identify the impacted architectural elements after requirements change. We present a change impact analysis technique for software architecture using architecture verification and semantics of traces. The technique is semi-automatic and requires participation of the software architect. Our technique has two parts. The first part is to identify the architectural elements that implement the system properties to which proposed requirements changes are introduced. By having the formal semantics of requirements relations and traces, we identify which parts of software architecture are impacted by a proposed change in requirements. We have extended TRIC for determining candidate impacted architectural elements. The second part of our technique is to propose possible changes for software architecture when the software architecture does not satisfy the new and/or changed requirements. The technique is based on architecture verification. The output of verification is a counter example if the requirements are not satisfied. The counter example is used with a classification of architectural changes in order to propose changes in the software architecture. These changes produce a new version of the architecture that possibly satisfies the new or the changed requirements

A knowledge based reengineering approach via ontology and description logic.

Traditional software reengineering often involves a great deal of manual effort by software maintainers. This is time consuming and error prone. Due to the knowledge intensive properties of software reengineering, a knowledge-based solution is proposed in this thesis to semi-automate some of this manual effort. This thesis aims to explore the principle research question: “How can software systems be described by knowledge representation techniques in order to semi-automate the manual effort in software reengineering?” The underlying research procedure of this thesis is scientific method, which consists of: observation, proposition, test and conclusion. Ontology and description logic are employed to model and represent the knowledge in different software systems, which is integrated with domain knowledge. Model transformation is used to support ontology development. Description logic is used to implement ontology mapping algorithms, in which the problem of detecting semantic relationships is converted into the problem of deducing the satisfiability of logical formulae. Operating system ontology has been built with a top-down approach, and it was deployed to support platform specific software migration [132] and portable software development [18]. Data-dominant software ontology has been built via a bottom-up approach, and it was deployed to support program comprehension [131] and modularisation [130]. This thesis suggests that software systems can be represented by ontology and description logic. Consequently, it will help in semi-automating some of the manual tasks in software reengineering. However, there are also limitations: bottom-up ontology development may sacrifice some complexity of systems; top-down ontology development may become time consuming and complicated. In terms of future work, a greater number of diverse software system categories could be involved and different software system knowledge could be explored

Inferring Complex Activities for Context-aware Systems within Smart Environments

The rising ageing population worldwide and the prevalence of age-related conditions such as physical fragility, mental impairments and chronic diseases have significantly impacted the quality of life and caused a shortage of health and care services. Over-stretched healthcare providers are leading to a paradigm shift in public healthcare provisioning. Thus, Ambient Assisted Living (AAL) using Smart Homes (SH) technologies has been rigorously investigated to help address the aforementioned problems. Human Activity Recognition (HAR) is a critical component in AAL systems which enables applications such as just-in-time assistance, behaviour analysis, anomalies detection and emergency notifications. This thesis is aimed at investigating challenges faced in accurately recognising Activities of Daily Living (ADLs) performed by single or multiple inhabitants within smart environments. Specifically, this thesis explores five complementary research challenges in HAR. The first study contributes to knowledge by developing a semantic-enabled data segmentation approach with user-preferences. The second study takes the segmented set of sensor data to investigate and recognise human ADLs at multi-granular action level; coarse- and fine-grained action level. At the coarse-grained actions level, semantic relationships between the sensor, object and ADLs are deduced, whereas, at fine-grained action level, object usage at the satisfactory threshold with the evidence fused from multimodal sensor data is leveraged to verify the intended actions. Moreover, due to imprecise/vague interpretations of multimodal sensors and data fusion challenges, fuzzy set theory and fuzzy web ontology language (fuzzy-OWL) are leveraged. The third study focuses on incorporating uncertainties caused in HAR due to factors such as technological failure, object malfunction, and human errors. Hence, existing studies uncertainty theories and approaches are analysed and based on the findings, probabilistic ontology (PR-OWL) based HAR approach is proposed. The fourth study extends the first three studies to distinguish activities conducted by more than one inhabitant in a shared smart environment with the use of discriminative sensor-based techniques and time-series pattern analysis. The final study investigates in a suitable system architecture with a real-time smart environment tailored to AAL system and proposes microservices architecture with sensor-based off-the-shelf and bespoke sensing methods. The initial semantic-enabled data segmentation study was evaluated with 100% and 97.8% accuracy to segment sensor events under single and mixed activities scenarios. However, the average classification time taken to segment each sensor events have suffered from 3971ms and 62183ms for single and mixed activities scenarios, respectively. The second study to detect fine-grained-level user actions was evaluated with 30 and 153 fuzzy rules to detect two fine-grained movements with a pre-collected dataset from the real-time smart environment. The result of the second study indicate good average accuracy of 83.33% and 100% but with the high average duration of 24648ms and 105318ms, and posing further challenges for the scalability of fusion rule creations. The third study was evaluated by incorporating PR-OWL ontology with ADL ontologies and Semantic-Sensor-Network (SSN) ontology to define four types of uncertainties presented in the kitchen-based activity. The fourth study illustrated a case study to extended single-user AR to multi-user AR by combining RFID tags and fingerprint sensors discriminative sensors to identify and associate user actions with the aid of time-series analysis. The last study responds to the computations and performance requirements for the four studies by analysing and proposing microservices-based system architecture for AAL system. A future research investigation towards adopting fog/edge computing paradigms from cloud computing is discussed for higher availability, reduced network traffic/energy, cost, and creating a decentralised system. As a result of the five studies, this thesis develops a knowledge-driven framework to estimate and recognise multi-user activities at fine-grained level user actions. This framework integrates three complementary ontologies to conceptualise factual, fuzzy and uncertainties in the environment/ADLs, time-series analysis and discriminative sensing environment. Moreover, a distributed software architecture, multimodal sensor-based hardware prototypes, and other supportive utility tools such as simulator and synthetic ADL data generator for the experimentation were developed to support the evaluation of the proposed approaches. The distributed system is platform-independent and currently supported by an Android mobile application and web-browser based client interfaces for retrieving information such as live sensor events and HAR results

Ingénierie des exigences pour la conception d'architectures de sécurité de systèmes embarqués distribués

During the last ten years, the impact of security concerns on the development and exploration of distributed embedded systems never ceased to grow. This is mainly related to the fact that these systems are increasingly interconnected and thus vulnerable to attacks, and that the economic interest in attacking them has simultane- ously increased. In such a context, requirement engineering methodologies and tools have become necessary to take appropriate decisions regarding security early on. Security requirements engineering should thus strongly support the elicitation and specifica- tion of software security issues and solutions well before designers and developers are committed to a particular implementation. However, and that is especially true in embedded systems, security requirements should not be considered only as the abstract expression of a set of properties independently from the system architecture or from the threats and attacks that may occur. We believe this consideration is of utmost importance for security requirements engineering to be the driving force behind the design and implementation of a secure system. We thus describe in this thesis a security engineering requirement methodology depending upon a constant dialog between the design of system functions, the requirements that are attached to them, the design and development of the system architecture, and the assessment of the threats to system assets. Our approach in particular relies on a knowledge-centric approach to security requirement engineering, applicable from the early phases of system conceptualization to the enforcement of security requirements.Au cours des dix dernières années, l’impact des questions de sécurité sur le développement et la mise en oeuvre des systèmes embarqués distribués n’a jamais cessé de croître. Ceci est principalement lié à l’interconnexion toujours plus importante de ces systèmes qui les rend vulnérables aux attaques, ainsi qu’à l’intérêt économique d’attaquer ces systèmes qui s’est simultanément accru. Dans un tel contexte, méthodologies et outils d’ingénierie des exigences de sécurité sont devenus indispensables pour prendre des décisions appropriées quant a` la sécurité, et ce le plus tôt possible. L’ingénierie des exigences devrait donc fournir une aide substantielle à l’explicitation et à la spécification des problèmes et solutions de sécurité des logiciels bien avant que concepteurs et développeurs ne soient engagés dans une implantation en particulier. Toutefois, et c’est particulièrement vrai dans les systèmes embarqués, les exigences de sécurité ne doivent pas être considérées seulement comme l’expression abstraite d’un ensemble de propriétés indépendamment de l’architecture système ou des menaces et des attaques qui pourraient y survenir. Nous estimons que cette considération est d’une importance capitale pour faire de l’ingénierie des exigences un guide et un moteur de la conception et de la mise en œuvre d’un système sécurisé. Notre approche s’appuie en particulier sur une approche centrée sur les connaissances de l’ingénierie des exigences de sécurité, applicable dès les premières phases de conception du système jusqu’à la mise en application des exigences de sécurité dans l’implantation