Reliability prediction in model driven development

Evaluating the implications of an architecture design early in the software development lifecycle is important in order to reduce costs of development. Reliability is an important concern with regard to the correct delivery of software system service. Recently, the UML Profile for Modeling Quality of Service has defined a set of UML extensions to represent dependability concerns (including reliability) and other non-functional requirements in early stages of the software development lifecycle. Our research has shown that these extensions are not comprehensive enough to support reliability analysis for model-driven software engineering, because the description of reliability characteristics in this profile lacks support for certain dynamic aspects that are essential in modeling reliability. In this work, we define a profile for reliability analysis by extending the UML 2.0 specification to support reliability prediction based on scenario specifications. A UML model specified using the profile is translated to a labelled transition system (LTS), which is used for automated reliability prediction and identification of implied scenarios; the results of this analysis are then fed back to the UML model. The result is a comprehensive framework for addressing software reliability modeling, including analysis and evolution of reliability predictions. We exemplify our approach using the Boiler System used in previous work and demonstrate how reliability analysis results can be integrated into UML models

Integrating the ConcernBASE Approach with SADL

We describe ConcernBASE, a UML-based approach that is an instantiation of the IEEE's Conceptual Framework (Std 1471) for describing software architectures. We show how the approach supports advanced separation of concerns in software architecture by allowing one to identify and define multiple viewpoints, concern spaces and views of an architecture. Our work focuses on integrating the ConcernBASE approach with the Structural Architecture Description Language (SADL) in order to make the verification capabilities of SADL available to those who develop in UML. The result is a UML profile for structural description of software architecture. The paper also presents a prototype tool that supports this UML profile

From AOP to UML: Towards an Aspect-Oriented Architectural Modeling Approach

Capturing concerns that crosscut the boundaries of multiple components in software architecture descriptions is problematic. Standard description languages, such as UML, do not provide adequate means to understand and modularize such concerns, but aspect-oriented programming techniques do. This paper explores and analyzes the suitability of UML for aspect-oriented architectural modeling. It takes a bottom-up approach, starting from the code level to the level of software architecture description, via aspect-oriented design, using standard UML

Task 19 : software architecture

This document will cover the software architecture of the current WebPA system in use at Loughborough University. Within the document, the definition of the term software architecture is covered, as it has various meanings dependant on which angle is taken. The architecture description language is also identified. This will be used in the rest of the document to aid in the understanding of the different software architectures described. In order for the reader to understand this document they will need to have some familiarity with the concept of software architecture. Time has been taken to explain the concept and the main areas of software architecture that will be covered within this document. In order to read and understand the diagrams used to describe the software architecture it is useful for the reader to understand the main elements of UML. The constructs of UML will not be examined and are beyond the scope of this document. However, all efforts have been made to explain the diagrams to the user

Towards a UML Profile for Software Architecture

To formally describe architectures of software systems, specific languages called Architecture Description Languages (ADLs) have been developed by academic institutions and research labs. However, more and more research and industrial projects are using the standard Unified Modeling Language (UML) for representing software architectures of systems. In this paper, we focus on how to extend the UML by incorporating some key abstractions found in current ADLs, such as connectors, components and configurations, and how the UML can be used for modeling architectural viewpoints. Our approach is demonstrated by the software architecture of a video surveillance system. It is therefore the purpose of the paper to show that a UML profile for software architecture is needed

Pattern Reification as the Basis for Description-Driven Systems

One of the main factors driving object-oriented software development for information systems is the requirement for systems to be tolerant to change. To address this issue in designing systems, this paper proposes a pattern-based, object-oriented, description-driven system (DDS) architecture as an extension to the standard UML four-layer meta-model. A DDS architecture is proposed in which aspects of both static and dynamic systems behavior can be captured via descriptive models and meta-models. The proposed architecture embodies four main elements - firstly, the adoption of a multi-layered meta-modeling architecture and reflective meta-level architecture, secondly the identification of four data modeling relationships that can be made explicit such that they can be modified dynamically, thirdly the identification of five design patterns which have emerged from practice and have proved essential in providing reusable building blocks for data management, and fourthly the encoding of the structural properties of the five design patterns by means of one fundamental pattern, the Graph pattern. A practical example of this philosophy, the CRISTAL project, is used to demonstrate the use of description-driven data objects to handle system evolution.Comment: 20 pages, 10 figure

QuantUM: Quantitative Safety Analysis of UML Models

When developing a safety-critical system it is essential to obtain an assessment of different design alternatives. In particular, an early safety assessment of the architectural design of a system is desirable. In spite of the plethora of available formal quantitative analysis methods it is still difficult for software and system architects to integrate these techniques into their every day work. This is mainly due to the lack of methods that can be directly applied to architecture level models, for instance given as UML diagrams. Also, it is necessary that the description methods used do not require a profound knowledge of formal methods. Our approach bridges this gap and improves the integration of quantitative safety analysis methods into the development process. All inputs of the analysis are specified at the level of a UML model. This model is then automatically translated into the analysis model, and the results of the analysis are consequently represented on the level of the UML model. Thus the analysis model and the formal methods used during the analysis are hidden from the user. We illustrate the usefulness of our approach using an industrial strength case study.Comment: In Proceedings QAPL 2011, arXiv:1107.074

Towards a design-by-contract based approach for realizable connector-centric software architectures

Despite being a widely-used language for specifying software systems, UML remains less than ideal for software architectures. Architecture description languages (ADLs) were developed to provide more comprehensive support. However, so far the application of ADLs in practice has been impeded by at least one of the following problems: (i) advanced formal notations, (ii) lack of support for complex connectors, and (iii) potentially unrealizable designs. In this paper we propose a new ADL that is based on Design-by-Contract (DbC) for specifying software architectures. While DbC promotes a formal and precise way of specifying system behaviours, it is more familiar to practising developers, thus allowing for a more comfortable way of specifying architectures than using process algebras. Furthermore, by granting connectors a first-class status, our ADL allows designers to specify not only simple interaction mechanisms as connectors but also complex interaction protocols. Finally, in order to ensure that architectural designs are always realizable we eliminate potentially unrealizable constructs in connector specifications (the connector “glue”)

Non-functional property analysis using UML2.0 and model transformations

Real-time embedded architectures consist of software and hardware parts. Meeting non-functional constraints (e.g., real-time constraints) greatly depends on the mappings from the system functionalities to software and hardware components. Thus, there is a strong demand for precise architecture and allocation modeling, amenable to performance analysis. The report proposes a model-driven approach for the assessment of the quality of allocations of the system functionalities to the architecture. We consider two technical domains: the UML domain for the definition of the model elements (for both description and analysis), and an analysis domain, external to UML, used for formal verification. This report defines three meta-models, one for each domain, and provides automated transformations within and between these domains. A special attention is then paid to temporal property analysis, based on a particular analysis model: the Modular and Hierarchical Time Petri Nets