Component-Based Software Engineering - New Challenges in Software Development

The primary role of component-based software engineering is to address the development of systems as an assembly of parts (components), the development of parts as reusable entities, and the maintenance and upgrading of systems by customising and replacing such parts. This requires established methodologies and tool support covering the entire component and system lifecycle including technological, organisational, marketing, legal, and other aspects. The traditional disciplines from software engineering need new methodologies to support component-based development

Component-based software engineering: a quantitative approach

Dissertação apresentada para a obtenção do Grau de Doutor em Informática pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaBackground: Often, claims in Component-Based Development (CBD) are only supported by qualitative expert opinion, rather than by quantitative data. This contrasts with the normal practice in other sciences, where a sound experimental validation of claims is standard practice. Experimental Software Engineering (ESE) aims to bridge this gap. Unfortunately, it is common to find experimental validation efforts that are hard to replicate and compare, to build up the body of knowledge in CBD. Objectives: In this dissertation our goals are (i) to contribute to evolution of ESE, in what concerns the replicability and comparability of experimental work, and (ii) to apply our proposals to CBD, thus contributing to its deeper and sounder understanding. Techniques: We propose a process model for ESE, aligned with current experimental best practices, and combine this model with a measurement technique called Ontology-Driven Measurement (ODM). ODM is aimed at improving the state of practice in metrics definition and collection, by making metrics definitions formal and executable,without sacrificing their usability. ODM uses standard technologies that can be well adapted to current integrated development environments. Results: Our contributions include the definition and preliminary validation of a process model for ESE and the proposal of ODM for supporting metrics definition and collection in the context of CBD. We use both the process model and ODM to perform a series experimental works in CBD, including the cross-validation of a component metrics set for JavaBeans, a case study on the influence of practitioners expertise in a sub-process of component development (component code inspections), and an observational study on reusability patterns of pluggable components (Eclipse plug-ins). These experimental works implied proposing, adapting, or selecting adequate ontologies, as well as the formal definition of metrics upon each of those ontologies. Limitations: Although our experimental work covers a variety of component models and, orthogonally, both process and product, the plethora of opportunities for using our quantitative approach to CBD is far from exhausted. Conclusions: The main contribution of this dissertation is the illustration, through practical examples, of how we can combine our experimental process model with ODM to support the experimental validation of claims in the context of CBD, in a repeatable and comparable way. In addition, the techniques proposed in this dissertation are generic and can be applied to other software development paradigms.Departamento de Informática of the Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT/UNL); Centro de Informática e Tecnologias da Informação of the FCT/UNL; Fundação para a Ciência e Tecnologia through the STACOS project(POSI/CHS/48875/2002); The Experimental Software Engineering Network (ESERNET);Association Internationale pour les Technologies Objets (AITO); Association forComputing Machinery (ACM

Re-use of tests and arguments for assesing dependable mixed-critically systems

The safety assessment of mixed-criticality systems (MCS) is a challenging activity due to system heterogeneity, design constraints and increasing complexity. The foundation for MCSs is the integrated architecture paradigm, where a compact hardware comprises multiple execution platforms and communication interfaces to implement concurrent functions with different safety requirements. Besides a computing platform providing adequate isolation and fault tolerance mechanism, the development of an MCS application shall also comply with the guidelines defined by the safety standards. A way to lower the overall MCS certification cost is to adopt a platform-based design (PBD) development approach. PBD is a model-based development (MBD) approach, where separate models of logic, hardware and deployment support the analysis of the resulting system properties and behaviour. The PBD development of MCSs benefits from a composition of modular safety properties (e.g. modular safety cases), which support the derivation of mixed-criticality product lines. The validation and verification (V&V) activities claim a substantial effort during the development of programmable electronics for safety-critical applications. As for the MCS dependability assessment, the purpose of the V&V is to provide evidences supporting the safety claims. The model-based development of MCSs adds more V&V tasks, because additional analysis (e.g., simulations) need to be carried out during the design phase. During the MCS integration phase, typically hardware-in-the-loop (HiL) plant simulators support the V&V campaigns, where test automation and fault-injection are the key to test repeatability and thorough exercise of the safety mechanisms. This dissertation proposes several V&V artefacts re-use strategies to perform an early verification at system level for a distributed MCS, artefacts that later would be reused up to the final stages in the development process: a test code re-use to verify the fault-tolerance mechanisms on a functional model of the system combined with a non-intrusive software fault-injection, a model to X-in-the-loop (XiL) and code-to-XiL re-use to provide models of the plant and distributed embedded nodes suited to the HiL simulator, and finally, an argumentation framework to support the automated composition and staged completion of modular safety-cases for dependability assessment, in the context of the platform-based development of mixed-criticality systems relying on the DREAMS harmonized platform.La dificultad para evaluar la seguridad de los sistemas de criticidad mixta (SCM) aumenta con la heterogeneidad del sistema, las restricciones de diseño y una complejidad creciente. Los SCM adoptan el paradigma de arquitectura integrada, donde un hardware embebido compacto comprende múltiples plataformas de ejecución e interfaces de comunicación para implementar funciones concurrentes y con diferentes requisitos de seguridad. Además de una plataforma de computación que provea un aislamiento y mecanismos de tolerancia a fallos adecuados, el desarrollo de una aplicación SCM además debe cumplir con las directrices definidas por las normas de seguridad. Una forma de reducir el coste global de la certificación de un SCM es adoptar un enfoque de desarrollo basado en plataforma (DBP). DBP es un enfoque de desarrollo basado en modelos (DBM), en el que modelos separados de lógica, hardware y despliegue soportan el análisis de las propiedades y el comportamiento emergente del sistema diseñado. El desarrollo DBP de SCMs se beneficia de una composición modular de propiedades de seguridad (por ejemplo, casos de seguridad modulares), que facilitan la definición de líneas de productos de criticidad mixta. Las actividades de verificación y validación (V&V) representan un esfuerzo sustancial durante el desarrollo de aplicaciones basadas en electrónica confiable. En la evaluación de la seguridad de un SCM el propósito de las actividades de V&V es obtener las evidencias que apoyen las aseveraciones de seguridad. El desarrollo basado en modelos de un SCM incrementa las tareas de V&V, porque permite realizar análisis adicionales (por ejemplo, simulaciones) durante la fase de diseño. En las campañas de pruebas de integración de un SCM habitualmente se emplean simuladores de planta hardware-in-the-loop (HiL), en donde la automatización de pruebas y la inyección de faltas son la clave para la repetitividad de las pruebas y para ejercitar completamente los mecanismos de tolerancia a fallos. Esta tesis propone diversas estrategias de reutilización de artefactos de V&V para la verificación temprana de un MCS distribuido, artefactos que se emplearán en ulteriores fases del desarrollo: la reutilización de código de prueba para verificar los mecanismos de tolerancia a fallos sobre un modelo funcional del sistema combinado con una inyección de fallos de software no intrusiva, la reutilización de modelo a X-in-the-loop (XiL) y código a XiL para obtener modelos de planta y nodos distribuidos aptos para el simulador HiL y, finalmente, un marco de argumentación para la composición automatizada y la compleción escalonada de casos de seguridad modulares, en el contexto del desarrollo basado en plataformas de sistemas de criticidad mixta empleando la plataforma armonizada DREAMS.Kritikotasun nahastuko sistemen segurtasun ebaluazioa jarduera neketsua da beraien heterogeneotasuna dela eta. Sistema hauen oinarria arkitektura integratuen paradigman datza, non hardware konpaktu batek exekuzio plataforma eta komunikazio interfaze ugari integratu ahal dituen segurtasun baldintza desberdineko funtzio konkurrenteak inplementatzeko. Konputazio plataformek isolamendu eta akatsen aurkako mekanismo egokiak emateaz gain, segurtasun arauek definituriko jarraibideak jarraitu behar dituzte kritikotasun mistodun aplikazioen garapenean. Sistema hauen zertifikazio prozesuaren kostua murrizteko aukera bat plataformetan oinarritutako garapenean (PBD) datza. Garapen planteamendu hau modeloetan oinarrituriko garapena da (MBD) non modeloaren logika, hardware eta garapen desberdinak sistemaren propietateen eta portaeraren aurka aztertzen diren. Kritikotasun mistodun sistemen PBD garapenak etekina ateratzen dio moduluetan oinarrituriko segurtasun propietateei, adibidez: segurtasun kasu modularrak (MSC). Modulu hauek kritikotasun mistodun produktu-lerroak ere hartzen dituzte kontutan. Berifikazio eta balioztatze (V&V) jarduerek esfortzu kontsideragarria eskatzen dute segurtasun-kiritikoetarako elektronika programagarrien garapenean. Kritikotasun mistodun sistemen konfiantzaren ebaluazioaren eta V&V jardueren helburua segurtasun eskariak jasotzen dituzten frogak proportzionatzea da. Kritikotasun mistodun sistemen modelo bidezko garapenek zeregin gehigarriak atxikitzen dizkio V&V jarduerari, fase honetan analisi gehigarriak (hots, simulazioak) zehazten direlako. Bestalde, kritikotasun mistodun sistemen integrazio fasean, hardware-in-the-loop (Hil) simulazio plantek V&V iniziatibak sostengatzen dituzte non testen automatizazioan eta akatsen txertaketan funtsezko jarduerak diren. Jarduera hauek frogen errepikapena eta segurtasun mekanismoak egiaztzea ahalbidetzen dute. Tesi honek V&V artefaktuen berrerabilpenerako estrategiak proposatzen ditu, kritikotasun mistodun sistemen egiaztatze azkarrerako sistema mailan eta garapen prozesuko azken faseetaraino erabili daitezkeenak. Esate baterako, test kodearen berrabilpena akats aurkako mekanismoak egiaztatzeko, modelotik X-in-the-loop (XiL)-ra eta kodetik XiL-rako konbertsioa HiL simulaziorako eta argumentazio egitura bat DREAMS Europear proiektuan definituriko arkitektura estiloan oinarrituriko segurtasun kasu modularrak automatikoki eta gradualki sortzeko

Determining criteria for selecting software components: lessons learned

Software component selection is growing in importance. Its success relies on correctly assessing the candidate components' quality. For a particular project, you can assess quality by identifying and analyzing the criteria that affect it. Component selection is on the suitability and completeness of the criteria used for evaluation. Experiences from determining criteria for several industrial projects provide important lessons. For a particular selection process, you can organize selection criteria into a criteria catalog. A CC is built for a scope, which can be either a domain (workflow systems, mail servers, antivirus tools, and so on) or a category of domains (communication infrastructure, collaboration software, and so on). Structurally, a CC arranges selection criteria in a hierarchical tree-like structure. The higher-level selection criteria serve to classify more concrete selection criteria, usually allowing some overlap. They also serve to leverage the CC.Peer ReviewedPostprint (published version

Strategies for the intelligent selection of components

It is becoming common to build applications as component-intensive systems - a mixture of fresh code and existing components. For application developers the selection of components to incorporate is key to overall system quality - so they want the `best\u27. For each selection task, the application developer will de ne requirements for the ideal component and use them to select the most suitable one. While many software selection processes exist there is a lack of repeatable, usable, exible, automated processes with tool support. This investigation has focussed on nding and implementing strategies to enhance the selection of software components. The study was built around four research elements, targeting characterisation, process, strategies and evaluation. A Post-positivist methodology was used with the Spiral Development Model structuring the investigation. Data for the study is generated using a range of qualitative and quantitative methods including a survey approach, a range of case studies and quasiexperiments to focus on the speci c tuning of tools and techniques. Evaluation and review are integral to the SDM: a Goal-Question-Metric (GQM)-based approach was applied to every Spiral

Putting Teeth into Open Architectures: Infrastructure for Reducing the Need for Retesting

Proceedings Paper (for Acquisition Research Program)The Navy is currently implementing the open-architecture framework for developing joint interoperable systems that adapt and exploit open-system design principles and architectures. This raises concerns about how to practically achieve dependability in software-intensive systems with many possible configurations when: 1) the actual configuration of the system is subject to frequent and possibly rapid change, and 2) the environment of typical reusable subsystems is variable and unpredictable. Our preliminary investigations indicate that current methods for achieving dependability in open architectures are insufficient. Conventional methods for testing are suited for stovepipe systems and depend strongly on the assumptions that the environment of a typical system is fixed and known in detail to the quality-assurance team at test and evaluation time. This paper outlines new approaches to quality assurance and testing that are better suited for providing affordable reliability in open architectures, and explains some of the additional technical features that an Open Architecture must have in order to become a Dependable Open Architecture.Naval Postgraduate School Acquisition Research ProgramApproved for public release; distribution is unlimited

The Early Assessment of System Performance in Distributed Real-time Systems

Distributed real-time process control systems are notoriously difficult to develop. They frequently overrun time schedules and break cost constraints. The problems are compounded where there are multiple development teams and stakeholders. Conventional model-driven development has been examined to see if it can be extended to resolve some of these problems. It may be possible to use early system design stages to identify performance issues which would otherwise not be identified until late in the development of the system. A functional model is proposed, in addition to those conventionally used for model-driven development, based on loosely coupled functional elements, to represent the behaviour of each system component. The model complements existing requirements and design specifications and addresses the combination of individual component abstractions to produce a complete system specification. The functional model enables the accurate prediction of system performance prior to the detailed design of each component. The thesis examines how performance can be calculated and modelled. An animator tool and associated code generator are used to predict system and component performance in a distributed aircraft navigation system. The use of the animator to support the system design prior to the generation of the component contract specifications and interface control documents provides a means of assessing performance which is accessible to domain experts and system designers alike. The model also enables the effects of requirements changes and component design issues on the system design to be assessed in terms of the system design to provide system wide solutions. This performance assessment model and animator compliments the existing 'fix-it-later' approach, reducing the chances of performance failure detected late during the system development process when they are most expensive to fix

Requirements Engineering

Requirements Engineering (RE) aims to ensure that systems meet the needs of their stakeholders including users, sponsors, and customers. Often consid- ered as one of the earliest activities in software engineering, it has developed into a set of activities that touch almost every step of the software development process. In this chapter, we reflect on how the need for RE was first recognised and how its foundational concepts were developed. We present the seminal papers on four main activities of the RE process, namely (i) elicitation, (ii) modelling & analysis, (iii) as- surance, and (iv) management & evolution. We also discuss some current research challenges in the area, including security requirements engineering as well as RE for mobile and ubiquitous computing. Finally, we identify some open challenges and research gaps that require further exploration