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

Variability-Modelling Practices in Industrial Software Product Lines: A Qualitative Study

Many organizations have transitioned from single-systems development to product-line development with the goal of increasing productivity and facilitating mass customization. Variability modelling is a key activity in software product-line development that deals with the explicit representation of variability using dedicated models. Variability models specify points of variability and their variants in a product line. Although many variability-modelling notations and tools have been designed by researchers and practitioners, very little is known about their usage, actual benefits or challenges. Existing studies mostly describe product-line practices in general, with little focus on variability modelling. We address this gap through a qualitative study on variability-modelling practices in medium- and large-scale companies using two empirical methods: surveys and interviews. We investigated companies' variability-modelling practices and experiences with the aim to gather information on 1) the methods and strategies used to create and manage variability models, 2) the tools and notations used for variability modelling, 3) the perceived values and challenges of variability modelling, and 4) the core characteristics of their variability models. Our results show that variability models are often created by re-engineering existing products into a product line. All of the interviewees and the majority of survey participants indicated that they represent variability using separate variability models rather than annotative approaches. We found that developers use variability models for many purposes, such as the visualization of variabilities, configuration of products, and scoping of products. Although we observed that high degree of heterogeneity exists in the variability-modelling notations and tools used by organizations, feature-based notations and tools are the most common. We saw huge differences in the sizes of variability models and their contents, which indicate that variability models can have different use cases depending on the organization. Most of our study participants reported complexity challenges that were related mainly to the visualization and evolution of variability models, and dependency management. In addition, reports from interviews suggest that product-line adoption and variability modelling have forced developers to think in terms of a product-line scenario rather than a product-based scenario

Toward Optimizing Distributed Programs Directed by Configurations

Networks of workstations are now viable environments for running distributed and parallel applications. Recent advances in software interconnection technology enables programmers to prepare applications to run in dynamically changing environments because module interconnection activity is regarded as an essentially distinct and different intellectual activity so as isolated from that of implementing individual modules. But there remains the question of how to optimize the performance of those applications for a given execution environment: how can developers realize performance gains without paying a high programming cost to specialize their application for the target environment? Interconnection technology has allowed programmers to tailor and tune their applications on distributed environments, but the traditional approach to this process has ignored the performance issue over gracefully seemless integration of various software components

Antiglycation and antioxidant properties of Momordica charantia

Diabetes mellitus is a multifactorial disorder characterised by hyperglycaemia and leads to complications. These complications are caused by advanced glycation endproducts (AGEs) that form through protein glycation as a consequence of hyperglycaemia. A diversity of plants are utilised worldwide as traditional medications for the treatment of diabetes mellitus, particularly in developing nations. A considerable quantity of literature has been published on Momordica charantia (MC) as a potent folk medicine for diabetes mellitus. The aim of this study was to investigate the antiglycation and antioxidant effects of HWE and CWE of MC on protein glycation. To examine whether MC can inhibit oxidative stress in endothelial cells by studying oxidative stress-related transcription factor parameters and their expression. Model proteins such as lysozyme and BSA were glycated using sugars (glucose and methylglyoxal) as glycating agents both in the presence and absence of MC extracts. AGE formation and inhibition were monitored by a number of methods. Furthermore, different antioxidant assays were used to study the antioxidant properties of MC. The inhibitory effects of AGEs, glucose, methylglyoxal and MC extracts on proliferation of cultured BAEC were determined in this research. Western blotting was used to examine the potential modulation of the oxidative stress signalling pathways induced by AGEs. Both extracts of MC inhibited the production of AGEs in a dose-dependent fashion and the HWE exhibited the more potent inhibitory effect on AGEs production. Moreover, parameters of oxidative stress including the expression of oxidative stress-related transcription factors were assessed using real-time PCR to study the protective effects of MC. The expressional inhibition of pro-oxidaive genes and enhancement anti-oidative enzymes could be potent element of vascular complications effect of MC extracts. Thus the aqueous extracts of MC, an edible vegetable, may have therapeutic potential in the management of diabetes mellitus