María José Rodríguez

REUBI: A Requirements Engineering method for ubiquitous systems

Recent technological advances are increasing the spread of Ubiquitous Computing, leading to the appearance of numerous software systems, which benefit from the features of this new paradigm. Nevertheless, there are a lack of methodologies to properly support the development process of these systems. An important part of the Software Engineering lifecycle is the Requirements Engineering stage, as it grounds the bases for system design for their success. In particular, systematically addressing Non-Functional Requirements such as dynamicity and adaptation, that are important features of ubiquitous systems, eventually leads to higher quality designs. In this paper, a Requirements Engineering Method for the analysis of Ubiquitous Systems, called REUBI, is introduced. It is a goal-based method that represents the influence of context and adverse situations, providing an evaluation procedure to help in the decision making about objectives satisfaction. The proposal is illustrated through the analysis of a Positioning Service of a real system. Additionally, the application of the method has been evaluated by a team of software engineers for the analysis of an Ambient Assisted Living (AAL) health care system.

A Representation of Software Systems Evolution Based on the Theory of the General System

The more commonly used software development methods assign the activities and results of the process of modification and evolution of software systems to maintenance. In this paper we present an approach to the representation of the evolution of these systems, based on Le Moignes theory of the General System, and a prototype developed in an object-oriented programming language which implements the concepts used.

HEDES: A System Theory Based Tool to Support Evolutionary Software Systems

Software systems evolve over time. Traditional software development methods and tools support partial aspects of this evolving process. Over the last few years we have researched into theoretical evolution search models which might be applied to the development of software systems. The Theory of Systems and biology have interesting views on the evolution process, very different from genetic algorithms, which may aid in the development of software systems and CASE tools. Our aim in this paper is to present a first version of a tool (HEDES) which includes these models and implements them in an object-oriented language (VisualWorks 3.0), using first-order temporal logic as support. In addition, some lessons learnt in the development of these complex and changing tools will be outlined, especially the importance of an iterative lifecycle in object-oriented development, a high degree of cohesion of the develop- ment team and the need for flexible and rapid ways of communicating new ideas using discussion meetings, Internet facilities and development support tools.

A Model-Driven Approach to Requirements Engineering in Ubiquitous Systems

Non-Functional Requirements (NFRs) are of paramount importance for the success of Ubiquitous Systems. However, existing methods and techniques to engineer these systems lack support in their specific and systematic treatment. In this paper, a specification technique and several models are introduced to deal with NFRs paying special attention to those particulary related to the features of Ambient Intelligence (AmI) and Ubiquitous Computing (UC). A Model-Driven approach is followed in order to enable the derivation of software designs for such systems. To this end, formal models and methods are defined, as well as an evaluation procedure to be applied, which aims to help designers to select the most appropriate solutions towards the satisfaction of quality attributes.

Context-Aware Self-adaptations: From Requirements Specification to Code Generation

Embedding context-aware self-adaptation mechanisms in pervasive systems is key to improve their acceptance by the users. These mechanisms involve a precise definition of the software structures that enable adding, removing or replacing components of the system to perform the adaptations. Typically the definition of these mechanisms is a complex and time consuming task. This paper presents a model-driven engineering approach to generate these context-aware self-adaptation mechanisms. The use of models transformations to define these mechanisms helps to reduce the complexity and effort required to define them. In order to illustrate the usefulness of the proposed approach, this paper reports its application to the development of a context-aware notification service.

Representation and Management of Memory and Decision in Evolving Software Systems

General System Theory recognizes a useful distinction in modelling the functionality and structure of the systems. Both concepts are applied tradionally in the development of Software Systems. The aim of this paper is to show the homogeneity between the functioning and the structure in a system and metasystem level in the MEDES software development method. Moreover, we will show how the management of the structural and functional histories can be carried out in a similar way allowing the realization of the necessary queries required in the evaluation of preconditions over the actions. In order to do that we define two kinds of queries (temporal and general queries) and we distinguish between the expressions that must be evaluated and their results. In order to manage these queries in an homogeneous way we have designed an object-oriented hierarchical structure of classes which can be used at the system and metasystem levels.

Applying model-driven engineering to a method for systematic treatment of NFRs in AmI systems

The satisfaction of Non-Functional Requirements NFRs has a clear impact in the success of Ambient Intelligence AmI Systems. However, existing methods and techniques to engineer these systems lack support in their specific and systematic treatment. In this paper, a Model-Driven Engineering MDE method for the design of AmI systems is introduced to deal with NFRs paying special attention to those particularly related to the features of these kind of systems, namely, unobtrusiveness, context-awareness, and self-adaptativeness. The aim is to enable the semi-automatic derivation of quality software design models from an NFRs specification of the system, with special focus on agent-oriented architectures. To this end, Computation Independent Models CIM and transformation techniques between them are defined, as well as an evaluation procedure to be applied, which can help developers to make successful solution decisions satisficing the overall quality properties required for AmI systems, and also specific ones for each particular system. The proposal is illustrated by means of a case study of an Ambient Assisted Living AAL system for elderly people.

Adaptation mechanisms based on quality properties: a case of study of a positioning service

Satisfaction of Non-Functional Requirements (NFR) in Ubiquitous Systems is specially important to guarantee the success in the development of those projects. However, the variety of existing solutions, each of them with different quality properties, together with the variability of the environments, force the designer to deal with a complicated task for their fulfillment. This paper presents the need for a design solution that enables the reconfiguration to obtain a set of adaptations for an indoor positioning service, with the purpose of satisfying the NFR that are expected at every moment. The proposal is illustrated through an application example where different scenarios are presented together with the corresponding adaptations that can be carried out.