Combining Multiple Granularity Variability in a Software Product Line Approach for Web Engineering

[Abstract] Context: Web engineering involves managing a high diversity of artifacts implemented in different languages and with different levels of granularity. Technological companies usually implement variable artifacts of Software Product Lines (SPLs) using annotations, being reluctant to adopt hybrid, often complex, approaches combining composition and annotations despite their benefits. Objective: This paper proposes a combined approach to support fine and coarse-grained variability for web artifacts. The proposal allows web developers to continue using annotations to handle fine-grained variability for those artifacts whose variability is very difficult to implement with a composition-based approach, but obtaining the advantages of the composition-based approach for the coarse-grained variable artifacts. Methods: A combined approach based on feature modeling that integrates annotations into a generic composition-based approach. We propose the definition of compositional and annotative variation points with custom-defined semantics, which is resolved by a scaffolding-based derivation engine. The approach is evaluated on a real-world web-based SPL by applying a set of variability metrics, as well as discussing its quality criteria in comparison with annotations, compositional, and combined existing approaches. Results: Our approach effectively handles both fine and coarse-grained variability. The mapping between the feature model and the web artifacts promotes the traceability of the features and the uniformity of the variation points regardless of the granularity of the web artifacts. Conclusions: Using well-known techniques of SPLs from an architectural point of view, such as feature modeling, can improve the design and maintenance of variable web artifacts without the need of introducing complex approaches for implementing the underlying variability.The work of the authors from the Universidad de Málaga is supported by the projects Magic P12-TIC1814 (post-doctoral research grant), MEDEA RTI2018-099213-B-I00 (co-financed by FEDER funds), Rhea P18-FR-1081 (MCI/AEI/FEDER, UE), LEIA UMA18-FEDERIA-157, TASOVA MCIU-AEI TIN2017-90644-REDT and, European Union’s H2020 research and innovation program under grant agreement DAEMON 101017109. The work of the authors from the Universidade da Coruña has been funded by MCIN/AEI/10.13039/501100011033, NextGenerationEU/PRTR, FLATCITY-POC: PDC2021-121239-C31 ; MCIN/AEI/10.13039/501100011033 EXTRACompact: PID2020-114635RB-I00 ; GAIN/Xunta de Galicia/ERDF CEDCOVID: COV20/00604 ; Xunta de Galicia/FEDER-UE GRC: ED431C 2021/53 ; MICIU/FEDER-UE BIZDEVOPSGLOBAL: RTI-2018-098309-B-C32 ; MCIN/AEI/10.13039/501100011033 MAGIST: PID2019-105221RB-C41Junta de Andalucía; P12-TIC-1814Universidad de Málaga; UMA18-FEDERIA-157Xunta de Galicia; COV20/00604Xunta de Galicia; ED431C 2021/53Junta de Andalucía; P18-FR-108

Energy efficient adaptation engines for android applications

Context The energy consumption of mobile devices is increasing due to the improvement in their components (e.g., better processors, larger screens). Although the hardware consumes the energy, the software is responsible for managing hardware resources such as the camera software and its functionality, and therefore, affects the energy consumption. Energy consumption not only depends on the installed code, but also on the execution context (environment, devices status) and how the user interacts with the application. Objective In order to reduce the energy consumption based on user behavior, it is necessary to dynamically adapt the application. However, the adaptation mechanism also consumes a certain amount of energy in itself, which may lead to an important increase in the energy expenditure of the application in comparison with the benefits of the adaptation. Therefore, this footprint must be measured and compared with the benefit obtained. Method In this paper, we (1) determine the benefits, in terms of energy consumption, of dynamically adapting mobile applications, based on user behavior; and (2) advocate the most energy-efficient adaptation mechanism. We provide four different implementations of a proposed adaptation model and measure their energy consumption. Results The proposed adaptation engines do not increase the energy consumption when compared to the benefits of the adaptation, which can reduce the energy consumption by up to 20%. Conclusion The adaptation engines proposed in this paper can decrease the energy consumption of the mobile devices based on user behavior. The overhead introduced by the adaptation engines is negligible in comparison with the benefits obtained by the adaptation.Junta de Andalucía MAGIC P12-TIC1814Ministerio de Economía y Competitividad TIN2015-64841-RMinisterio de Ciencia, Innovación y Universidades TIN2017-90644-REDTMinisterio de Ciencia, Innovación y Universidades RTI2018-099213-B-I00Universidad de Málaga LEIA UMA18-FEDERJA-15

A modular metamodel and refactoring rules to achieve software product line interoperability.

Emergent application domains, such as cyber–physical systems, edge computing or industry 4.0. present a high variability in software and hardware infrastructures. However, no single variability modeling language supports all language extensions required by these application domains (i.e., attributes, group cardinalities, clonables, complex constraints). This limitation is an open challenge that should be tackled by the software engineering field, and specifically by the software product line (SPL) community. A possible solution could be to define a completely new language, but this has a high cost in terms of adoption time and development of new tools. A more viable alternative is the definition of refactoring and specialization rules that allow interoperability between existing variability languages. However, with this approach, these rules cannot be reused across languages because each language uses a different set of modeling concepts and a different concrete syntax. Our approach relies on a modular and extensible metamodel that defines a common abstract syntax for existing variability modeling extensions. We map existing feature modeling languages in the SPL community to our common abstract syntax. Using our abstract syntax, we define refactoring rules at the language construct level that help to achieve interoperability between variability modeling languages.Work supported by the projects MEDEA RTI2018-099213-B-I00, IRIS PID2021-122812OB-I00 (co-financed by FEDER funds), Rhea P18-FR-1081 (MCI/AEI/FEDER, UE), LEIA UMA18-FEDERIA-157, and DAEMON H2020-101017109. // Funding for open access: Universidad de Málaga / CBUA

A first prototype of a new repository for feature model exchange and knowledge sharing

Feature models are the “de facto” standard for variability modelling and are used in both academia and industry. The MODEVAR initia tive tries to establish a common textual feature modelling language that can be used by different communities and can allow informa tion sharing. Feature model related researches use different models for different purposes such as analysis, sampling, testing, debug ging, teaching, etc. Those models are shared in private repositories and there is a risk that all that knowledge is spread across different platforms which hinder collaboration and knowledge reuse. In this paper, we propose a first working version of a new feature model repository that allows to centralise the knowledge generated in the community together with advanced capabilities such as DOI generation, an API, analysis reports, among others. Our solution is a front end interface that uses the popular open science repos itory Zenodo as an end point to materialise the storage of all the information. Zenodo is enhanced with characteristics that facilitate the management of the models. The idea of our repository is to provide existing but also new features that are not present in other repositories (e.g., SPLOT). We propose to populate our repository with all the existing models of many sources including SPLOT.Ministerio de Ciencia, Innovación y Universidades RTI2018-101204-B-C22 (OPHELIA)Agencia Estatal de Investigación TIN2017-90644-RED

Variability-aware data migration tool

Relational databases are widely present in the development of soft ware applications. A typical implementation can be seen in content management systems found on most websites. However, the migra tion of database structure and content between different manage ment systems is not trivial, and the manual creation of scripts makes it difficult to reuse them in other scenarios. This paper presents a tool for database migration by modeling what we call a migration product line. This tool allows to obtain different configurations resulting in final products in a semi-automatic way, i.e., products according to software requirements, considering the variability be tween any two relational databases. To study the feasibility of our proposal, we have implemented a proof of concept that performs the migration between two databases.Ministerio de Ciencia e Innovación RTI2018-101204-B-C22 (OPHELIA)Junta de Andalucía P20-01224 (COPERNICA)Junta de Andalucía METAMORFOSIS (US-1381375

Context-dependent reconfiguration of autonomous vehicles in mixed traffic

Human drivers naturally adapt their behaviour depending on the traffic conditions, such as the current weather and road type. Autonomous vehicles need to do the same, in a way that is both safe and efficient in traffic composed of both conventional and autonomous vehicles. In this paper, we demonstrate the applicability of a reconfigurable vehicle controller agent for autonomous vehicles that adapts the parameters of a used car-following model at runtime, so as to maintain a high degree of traffic quality (efficiency and safety) under different weather conditions.We follow a dynamic software product line approach to model the variability of the car-following model parameters, context changes and traffic quality, and generate specific configurations for each particular context. Under realistic conditions, autonomous vehicles have only a very local knowledge of other vehicles' variables.We investigate a distributed model predictive controller agent for autonomous vehicles to estimate their behavioural parameters at runtime, based on their available knowledge of the system.We show that autonomous vehicles with the proposed reconfigurable controller agent lead to behaviour similar to that achieved by human drivers, depending on the context.Junta de Andalucía MAGIC P12-TIC1814Ministerio de Ciencia, Innovación y Universidades HADAS TIN2015-64841-

FM fact label: a configurable and interactive visualization of feature model characterizations

Recognizing specific characteristics of feature models (FM) can be challenging due to the different nature and domains of the models. There are several metrics to characterize FMs. However, there is no standard way to visualize and identify the properties that make an FM unique and distinguishable. We propose FM Fact Label as a tool to visualize an FM characterization based on its metadata, structural measures, and analytical metrics. Although existing tools can provide a visualization of the FM and report some metrics, the feature diagram of large-scale FMs becomes ineffective to take an overall shape of the FM properties. Moreover, the reported metrics are often embedded in the tool user interface, preventing further analysis. FM Fact Label is a standalone web-based tool that provides a configurable and interactive visualization of FM characterizations that can be exported to several formats. Our contribution becomes important because the Universal Variability Language (UVL) is starting to gain attraction in the software product line community as a unified textual language to specify FMs and share knowledge. With this contribution, we help to advance the UVL ecosystem one step forward while providing a common representation for the results of existing analysis toolsMinisterio de Ciencia, Innovación y Universidades RTI2018-101204-B-C22 (OPHELIA)Junta de Andalucía P20-01224 (COPERNICA)Junta de Andalucía METAMORFOSIS (US-1381375)Ministerio de Economía y Competitividad RTI2018-099213-B-I00 (MEDEA)Ministerio de Ciencia e Innovación PID2021-122812OB-I00 (IRIS)Junta de Andalucía P18-FR-1081 (RHEA)Junta de Andalucía UMA18-FEDERIA-157 (LEIA)European Union H2020 101017109 (DAEMON

Empirical analysis of the tool support for software product lines

For the last ten years, software product line (SPL) tool developers have been facing the implementation of different variability requirements and the support of SPL engineering activities demanded by emergent domains. Despite systematic literature reviews identifying the main characteristics of existing tools and the SPL activities they support, these reviews do not always help to understand if such tools provide what complex variability projects demand. This paper presents an empirical research in which we evaluate the degree of maturity of existing SPL tools focusing on their support of variability modeling characteristics and SPL engineering activities required by current application domains. We first identify the characteristics and activities that are essential for the development of SPLs by analyzing a selected sample of case studies chosen from application domains with high variability. Second, we conduct an exploratory study to analyze whether the existing tools support those characteristics and activities. We conclude that, with the current tool support, it is possible to develop a basic SPL approach. But we have also found out that these tools present several limitations when dealing with complex variability requirements demanded by emergent application domains, such as non-Boolean features or large configuration spaces. Additionally, we identify the necessity for an integrated approach with appropriate tool support to completely cover all the activities and phases of SPL engineering. To mitigate this problem, we propose different road map using the existing tools to partially or entirely support SPL engineering activities, from variability modeling to product derivation.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Funding for open access charge: Universidad de Málaga / CBU

Dynamic Deployment and Monitoring of Security Policies

INTER-TRUST is a framework for the specification, negotiation, deployment and dynamic adaptation of interoperable security policies, in the context of pervasive systems where devices are constantly exchanging critical information through the network. The dynamic adaptation of the security policies at runtime is addressed using Aspect- Oriented Programming (AOP) that allows enforcing security requirements by dynamically weaving security aspects into the applications. However, a mechanism to guarantee the correct adaptation of the functionality that enforces the changing security policies is needed. In this paper, we present an approach with monitoring and detection techniques in order to maintain the correlation between the security policies and the associated functionality deployed using AOP, allowing the INTERTRUST framework automatically reacts when needed.European Union INTER-TRUST FP7-317731Ministerio de Economía y Competitividad TIN2012-34840Junta de Andalucía FamiWare P09-TIC-5231Junta de Andalucía MAGIC P12-TIC181