Lincoln S. Rocha

Requirements and challenges for building service-oriented pervasive middleware

The dinamicy and uncertainness of resources in mobile networks ask for novel uncoupled, adaptable and autonomous programming abstractions. Although applications are built upon a middleware layer that encapsulates some of that complexity, there is a lot left to fully explore the potential of ubiquitous and pervasive systems. To provide an insight on the challenges to develop interoperable middleware systems, this paper highlights the requirements to build service-oriented ubiquitous and pervasive middleware. These requirements are divided into primary and cross-cutting requirements. Primary requirements are Message Exchange, Mobility Support, Service Description, Discovery and Coordination, and Security. While Cross-cutting requirements are Context-Awareness and Adaptability, Autonomy, and QoS Requirements.

MobiLine: A Nested Software Product Line for the domain of mobile and context-aware applications

Mobile devices are multipurpose and multi-sensor equipments supporting applications able to adapt their behavior according to changes in the users context (device, location, time, etc.). Meanwhile, the development of mobile and context-aware software is not a simple task, mostly due to the peculiar characteristics of these devices. Although several solutions have been proposed to facilitate their development, reuse is not systematically used throughout the software development life-cycle. In this paper, we discuss an approach for the development of mobile and context-aware software using the Software Product Line (SPL) paradigm. Furthermore, a Nested SPL for the domain of mobile and context-aware applications is presented, lessons learned in the SPL development are discussed and a product for a context-aware visit guide is shown.

A software product line for the mobile and context-aware applications domain

The mobile and context-aware application domain presents challenging requirements to software development. Although several solutions have been proposed for this type of application, reuse is not systematically used throughout the software development lifecycle. Then, in this paper we propose an approach for the development of a mobile and context-aware Software Product Line (SPL). A SPL for the mobile and context-ware mobile guide domain is presented in order to illustrate the steps of the proposed approach. Furthermore, the lessons learned in the SPL development are discussed. Both approach and SPL are the main contributions of this paper.

A Decoupled and Interoperable Architecture for Coordination in Ubiquitous Systems

Com o avanço das tecnologias de hardware, como o surgimento de computadores menores com maior poder de processamento e armazenamento, e o progresso da comunicação de dados sem fio, a Computação Ubíqua se tornou uma realidade. Entretanto, o desenvolvimento de sistemas ubíquos ainda apresenta inúmeros desafios devido à grande diversidade e complexidade dos seus requisitos. Particularmente, em ambientes ubíquos onde a dinamicidade e a heterogeneidade de dispositivos e serviços são características comuns, a coordenação desacoplada e interoperável das atividades realizadas entre os agentes de software do sistema torna-se essencial. Assim, esse trabalho propõe uma arquitetura que proporciona meios de interação e coordenação desacoplados e interoperáveis para o desenvolvimento de sistemas ubíquos.

Test case design for context-aware applications

ContextCurrent software systems have increasingly implemented context-aware adaptations to handle the diversity of conditions of their surrounding environment. Therefore, people are becoming used to a variety of context-aware software systems (CASS). This context-awareness brings challenges to the software construction and testing because the context is unpredictable and may change at any time. Therefore, software engineers need to consider the dynamic context changes while testing CASS. Different test case design techniques (TCDT) have been proposed to support the testing of CASS. However, to the best of our knowledge, there is no analysis of these proposals on the advantages, limitations and their effective support to context variation during testing. ObjectiveTo gather empirical evidence on TCDT concerned with CASS by identifying, evaluating and synthesizing knowledge available in the literature. MethodTo undertake a secondary study (quasi-Systematic Literature Review) on TCDT for CASS regarding their assessed quality characteristics, used coverage criteria, test type, and test technique. ResultsFrom 833 primary studies published between 2004 and 2014, just 17 studies regard the design of test cases for CASS. Most of them focus on functional suitability. Furthermore, some of them take into account the changes in the context by providing specific test cases for each context configuration (static perspective) during the test execution. These 17 studies revealed five challenges affecting the design of test cases and 20 challenges regarding the testing of CASS. Besides, seven TCDT are not empirically evaluated. ConclusionA few TCDT partially support the testing of CASS. However, it has not been observed evidence on any TCDT supporting the truly context-aware testing, which that can adapt the expected output based on the context variation (dynamic perspective) during the test execution. It is an open issue deserving greater attention from researchers to increase the testing coverage and ensure users confidence in CASS.

MpOS: a multiplatform offloading system

Mobile applications and services have changed different aspects of modern life, besides allowing to be accessed by mobile devices at any moment, regardless of time and place. These devices usually interact with more powerful machines usually hosted at Internet on public clouds. This paper presents MpOS (Multiplatform Offloading System), a framework that supports a method-based offloading technique for applications of different mobile platforms, and was also developed initially for Android and Windows Phone. The framework provides several services to support the offloading process (e.g., discovery service, deployment service, and network profiler). In order to assess the proposed framework, we first developed an application using the MpOS framework for both Android and Windows Phone platforms. Finally, we performed an experiment to evaluate the developed applications performance. The result shows that offloading operation achieved a speedup of 14x running on cloudlet when compared with the execution on the mobile device.

Performing computation offloading on multiple platforms

An offloading framework designed for supporting multiple platforms is proposed.The solution supports Android and Windows Phone mobile applications.Developers can use static or dynamic offloading decision.The offloading technique improves the performance of mobile applications.The type of serialization used impacts the offloading performance. Mobile devices such as smart phones and tablets are increasingly important tools in daily routine. These devices generally interact with more powerful machines usually hosted on public clouds. In this context, this paper presents MpOS (Multiplatform Offloading System), a framework that supports a method-based offloading technique for applications of different mobile platforms (Android and Windows Phone). In addition, details of MpOS main components and services as well as code examples are presented. To evaluate the proposed solution and to analyse the impact of different serialization types on the offloading performance, we developed two applications and performed several experiments on both Android and Windows Phone platforms using WiFi and 4G/LTE connections to access the remote execution environments. Our results state that offloading to a cloudlet has provided the best performance for both Android and Windows Phone platforms, beyond showing that the type of serialization used by the framework directly impacts on the offloading performance.

An Architecture Proposal for Nested Software Product Lines in the Domain of Mobile and Context-Aware Applications

The domain of mobile and context-aware applications involves challenging requirements, such as mobility and adaptation, which makes the application development complex for this area. Considering this scenario, we used a nested software product line (SPL) that aims to facilitate the construction of such software by domain decomposition in two levels of analysis. The first concerns the characteristics of a generic SPL for the mobile and context-aware domain. The second is the requirement analysis of a business domain together with characteristics of the generic level. The goal of this paper is to propose a nested SPL.

Analyzing the Feature Models Maintainability over their Evolution Process: An Exploratory Study

The feature model is one of the most important artifact of a Software Product Line (SPL). It is built in the early stages of SPL development and describes the main features and relationships. The feature model evolves according to the evolution of the SPL. Thus, it is important to build maintainable feature models. In this scenario, measures have been proven useful in the maintainability evaluation of the feature models. This paper presents an exploratory study on the impact of feature models maintainability over the SPL evolution process. In order to support this analysis, we built a dataset containing a compiled set of 21 maintainability structural measures extracted from 16 feature models and respective versions. Although not conclusive, our findings indicate that the feature models maintainability tends to decrease as it evolves. We also identified the most common changes performed in a feature model during its evolution process.

Model Verification of Dynamic Software Product Lines

Dynamic Software Product Lines (DSPLs) extend the concept of Software Product Lines enabling adaptation at runtime according to context changes. Such dynamic behavior is typically designed using adaptation rules, context-triggered actions responsible for features activation and deactivation at runtime. The erroneous specification and the interleaving of adaptation rules (i.e., the parallel execution of adaptation rules) can lead DSPL to reach an undesired (improperly or defective) product configuration at runtime. Thus, in order to improve the reliability of DSPL behavior, design faults must be rigorously identified and eliminated in the early stages of DSPL development. In this paper, we address this issue introducing Dynamic Feature Transition Systems (DFTSs) that allow the modeling and formal verification of the DSPLs adaptive behavior. These transition systems are derived from the adaptation rules and a Context Kripke Structure, which is a context evolution model. Furthermore, we formally define five properties that can be used to identify existing design faults in DSPL design. Aiming to assess the feasibility of our approach, a feasibility study was conducted using two DSPLs, Mobile Visit Guides and Car. In both cases, design faults were automatically detected indicating that our formalism can help in the detection of design faults in the DSPLs adaptive behavior.