Tomás Ruiz-López

A survey on indoor positioning systems: Foreseeing a quality design

The plethora of current positioning technologies, each one with very different features, together with the variety of environments wherein they are to be implanted, force system architects to thoroughly consider the choice for one of them in an isolated way, without combinining several options. Additionally, what makes a technology very appropriate in a certain constraints, may be the result of failing to fulfill others. Thus, trade-off solutions are usually to be made. In this paper, we provide a survey on different positioning techniques in relation to the satisfaction of certain non-functional requirements such as accuracy, responsiveness, complexity, scalability, etc, so that it can serve as guide to system designers in their ultimate decisions. The survey serves as an analysis and intends to highlight the need to undertake a new design capable of adapting this kind of distributed systems to specific characteristics of those technologies and environments; this objective could be achieved on the basis of a design considering non-functional such as requirements.

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 Communication Model to Integrate the Request-Response and the Publish-Subscribe Paradigms into Ubiquitous Systems

The Request-Response (RR) paradigm is widely used in ubiquitous systems to exchange information in a secure, reliable and timely manner. Nonetheless, there is also an emerging need for adopting the Publish-Subscribe (PubSub) paradigm in this kind of systems, due to the advantages that this paradigm offers in supporting mobility by means of asynchronous, non-blocking and one-to-many message distribution semantics for event notification. This paper analyzes the strengths and weaknesses of both the RR and PubSub paradigms to support communications in ubiquitous systems and proposes an abstract communication model in order to enable their seamless integration. Thus, developers will be focused on communication semantics and the required quality properties, rather than be concerned about specific communication mechanisms. The aim is to provide developers with abstractions intended to decrease the complexity of integrating different communication paradigms commonly needed in ubiquitous systems. The proposal has been applied to implement a middleware and a real home automation system to show its applicability and benefits.

Towards a Reusable Design of a Positioning System for AAL Environments

There exists a large diversity of decisions to be dealt with in the design and construction of positioning systems, each of them implying different advantages and disadvantages. We present a design proposal which aims to provide reusable and adaptable support to Location-based Systems, through a reconfigurable positioning service composed of interoperable components. The interest of the proposal concerns the combination between different methods, algorithms and technologies to be selected in run-time so as to take advantage of the benefits of each one of them. The positioning system aims to use that technology which is more beneficial taking into account the quality properties that need to be fulfilled at a given time. For instance, the proposal enables AAL solutions to address indoor and outdoor positioning by means of the same service switching dynamically and automatically between methods and technologies, and combine two different methods simultaneously to improve accuracy. This research work also describe results obtained from a competition with other proposals.

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.

Requirements Systematization through Pattern Application in Ubiquitous Systems

Application of patterns to address Non-Functional Requirements (NFRs) is a field that has not been widely explored, and that is still uncovered in the scope of Ubiquitous Computing. The unique features of this paradigm, such as context-awareness or technological unobtrusiveness, present a challenge to appropriately treat the specific NFRs related to this field. In this paper, recurring situations in ubiquitous systems have been identified and captured as patterns, which can be used to satisfy NFRs in different domains.

SIGUEME: Technology-based intervention for low-functioning autism to train skills to work with visual signifiers and concepts

BACKGROUND People with low-functioning ASD and other disabilities often find it difficult to understand the symbols traditionally used in educational materials during the learning process. Technology-based interventions are becoming increasingly common, helping children with cognitive disabilities to perform academic tasks and improve their abilities and knowledge. Such children often find it difficult to perform certain tasks contained in educational materials since they lack necessary skills such as abstract reasoning. In order to help these children, the authors designed and created SIGUEME to train attention and the perceptual and visual cognitive skills required to work with and understand graphic materials and objects. METHODS A pre-test/post-test design was implemented to test SIGUEME. Seventy-four children with low-functioning ASD (age=13.47, SD=8.74) were trained with SIGUEME over twenty-five sessions and compared with twenty-eight children (age=12.61, SD=2.85) who had not received any intervention. RESULTS There was a statistically significant improvement in the experimental group in Attention (W=-5.497, p<0.001). There was also a significant change in Association and Categorization (W=2.721, p=0.007) and Interaction (W=-3.287, p=0.001). CONCLUSIONS SIGUEME is an effective tool for improving attention, categorization and interaction in low-functioning children with ASD. It is also a useful and powerful instrument for teachers, parents and educators by increasing the childs motivation and autonomy.

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.

Leveraging the Model-Driven Architecture for Service Choreography in Ubiquitous Systems

In ubiquitous systems, the context information (location, time, networking conditions, etc.) may influence the way of operation or even require to guarantee the availability of particular services at a certain moment. As a consequence, service composition may become more complex from a design viewpoint, due to the need of systematically taking into account all the variations of the contextual information in order to adapt the behavior of the set of involved services. Business Process Model and Notation 2.0 (BPMN 2.0) can be used to specify process choreography, which helps modeling service composition. Even so, the peculiarities of ubiquitous systems make it difficult to actually obtain an executable model that fulfills the mobility, availability and adaptability requirements of these systems. In this paper, it is presented a Model-Driven Architecture (MDA) approach to transform a BPMN choreography model into software templates for specific target platforms. The proposal has been implemented making use of the Eclipse Modeling Framework (EMF).