Product line architecture recovery with outlier filtering in software families: the Apo-Games case study

Software product line (SPL) approach has been widely adopted to achieve systematic reuse in families of software products. Despite its benefits, developing an SPL from scratch requires high up-front investment. Because of that, organizations commonly create product variants with opportunistic reuse approaches (e.g., copy-and-paste or clone-and-own). However, maintenance and evolution of a large number of product variants is a challenging task. In this context, a family of products developed opportunistically is a good starting point to adopt SPLs, known as extractive approach for SPL adoption. One of the initial phases of the extractive approach is the recovery and definition of a product line architecture (PLA) based on existing software variants, to support variant derivation and also to allow the customization according to customers’ needs. The problem of defining a PLA from existing system variants is that some variants can become highly unrelated to their predecessors, known as outlier variants. The inclusion of outlier variants in the PLA recovery leads to additional effort and noise in the common structure and complicates architectural decisions. In this work, we present an automatic approach to identify and filter outlier variants during the recovery and definition of PLAs. Our approach identifies the minimum subset of cross-product architectural information for an effective PLA recovery. To evaluate our approach, we focus on real-world variants of the Apo-Games family. We recover a PLA taking as input 34 Apo-Game variants developed by using opportunistic reuse. The results provided evidence that our automatic approach is able to identify and filter outlier variants, allowing to eliminate exclusive packages and classes without removing the whole variant. We consider that the recovered PLA can help domain experts to take informed decisions to support SPL adoption.This research was partially funded by INES 2.0; CNPq grants 465614/2014-0 and 408356/2018-9; and FAPESB grants JCB0060/2016 and BOL2443/201

What to Fix? Distinguishing between design and non-design rules in automated tools

Technical debt---design shortcuts taken to optimize for delivery speed---is a critical part of long-term software costs. Consequently, automatically detecting technical debt is a high priority for software practitioners. Software quality tool vendors have responded to this need by positioning their tools to detect and manage technical debt. While these tools bundle a number of rules, it is hard for users to understand which rules identify design issues, as opposed to syntactic quality. This is important, since previous studies have revealed the most significant technical debt is related to design issues. Other research has focused on comparing these tools on open source projects, but these comparisons have not looked at whether the rules were relevant to design. We conducted an empirical study using a structured categorization approach, and manually classify 466 software quality rules from three industry tools---CAST, SonarQube, and NDepend. We found that most of these rules were easily labeled as either not design (55%) or design (19%). The remainder (26%) resulted in disagreements among the labelers. Our results are a first step in formalizing a definition of a design rule, in order to support automatic detection.Comment: Long version of accepted short paper at International Conference on Software Architecture 2017 (Gothenburg, SE

A probabilistic threshold model: Analyzing semantic categorization data with the Rasch model

According to the Threshold Theory (Hampton, 1995, 2007) semantic categorization decisions come about through the placement of a threshold criterion along a dimension that represents items' similarity to the category representation. The adequacy of this theory is assessed by applying a formalization of the theory, known as the Rasch model (Rasch, 1960; Thissen & Steinberg, 1986), to categorization data for eight natural language categories and subjecting it to a formal test. In validating the model special care is given to its ability to account for inter- and intra-individual differences in categorization and their relationship with item typicality. Extensions of the Rasch model that can be used to uncover the nature of category representations and the sources of categorization differences are discussed

Evidence-based defect assessment and prediction for software product lines

The systematic reuse provided by software product lines provides opportunities to achieve increased quality and reliability as a product line matures. This has led to a widely accepted assumption that as a product line evolves, its reliability improves. However, evidence in terms of empirical investigation of the relationship among change, reuse and reliability in evolving software product lines is lacking. To address the problem this work investigates: 1) whether reliability as measured by post-deployment failures improves as the products and components in a software product line change over time, and 2) whether the stabilizing effect of shared artifacts enables accurate prediction of failure-prone files in the product line. The first part of this work performs defect assessment and investigates defect trends in Eclipse, an open-source software product line. It analyzes the evolution of the product line over time in terms of the total number of defects, the percentage of severe defects and the relationship between defects and changes. The second part of this work explores prediction of failure-prone files in the Eclipse product line to determine whether prediction improves as the product line evolves over time. In addition, this part investigates the effect of defect and data collection periods on the prediction performance. The main contributions of this work include findings that the majority of files with severe defects are reused files rather than new files, but that common components experience less change than variation components. The work also found that there is a consistent set of metrics which serve as prominent predictors across multiple products and reuse categories over time. Classification of post-release, failure-prone files using change data for the Eclipse product line gives better recall and false positive rates as compared to classification using static code metrics. The work also found that on-going change in product lines hinders the ability to predict failure-prone files, and that predicting post-release defects using pre-release change data for the Eclipse case study is difficult. For example, using more data from the past to predict future failure-prone files does not necessarily give better results than using data only from the recent past. The empirical investigation of product line change and defect data leads to an improved understanding of the interplay among change, reuse and reliability as a product line evolves

An Analysis of Measurement and Metrics Tools: A Systematic Literature Review

Measurement is an important field in Software Engineering, since it allows for organizations to obtain trustworthy estimates regarding deadlines, cost, and quality for the development of their software projects. Many tools are available for the calculation and storage of metrics and therefore, choosing the best tool can be a hard task. Faced with such a problem, this study carries out an analysis of the measurement tools presented in literature. The methodology chosen for the task was the systematic literature review. The results of the systematic review present the metric tools chosen in literature, their functionalities, and the main metrics used by these tools. The primary contribution of this article is a list with the metrics used by each of these tools, and their respective classification, according to their use in academia as well as in the software industry

Construction of embedded fMRI resting state functional connectivity networks using manifold learning

We construct embedded functional connectivity networks (FCN) from benchmark resting-state functional magnetic resonance imaging (rsfMRI) data acquired from patients with schizophrenia and healthy controls based on linear and nonlinear manifold learning algorithms, namely, Multidimensional Scaling (MDS), Isometric Feature Mapping (ISOMAP) and Diffusion Maps. Furthermore, based on key global graph-theoretical properties of the embedded FCN, we compare their classification potential using machine learning techniques. We also assess the performance of two metrics that are widely used for the construction of FCN from fMRI, namely the Euclidean distance and the lagged cross-correlation metric. We show that the FCN constructed with Diffusion Maps and the lagged cross-correlation metric outperform the other combinations

User Interface Matters : Analysing the Complexity of Mobile Applications from a Visual Perspective

Product-centric techniques to analyze mobile applications leverage traditional source code analysis, size, market success, complexity, and others. Many of these techniques converge in the strategy of evaluating metrics taken from the source code that delivers the functionality of the software product. However, when following the Model-View-Controller (MVC) architecture, mobile applications are typically constructed by a compound of at least two programming languages, one to deliver the functionality and the other to describe the visual aspects. The latter is commonly left out from source code analysis, even though critical parts of the application are present in the graphic User Interface (UI). In this paper, we identify an opportunity to strengthen the product-centric mobile app analysis by incorporating UI metrics. This approach aims to enhance the expressiveness of source code metrics and deliver a more comprehensive analysis of the complexity, maintainability, and effort estimation of a mobile app. To introduce the concept, we present a case study realized using a block-based programming language to create mobile apps, in which we describe and calculate functional and UI metrics, discover commonalities and differences, discuss traits, and open tracks for further research.Peer reviewe

Visual analysis of sensor logs in smart spaces: Activities vs. situations

Models of human habits in smart spaces can be expressed by using a multitude of representations whose readability influences the possibility of being validated by human experts. Our research is focused on developing a visual analysis pipeline (service) that allows, starting from the sensor log of a smart space, to graphically visualize human habits. The basic assumption is to apply techniques borrowed from the area of business process automation and mining on a version of the sensor log preprocessed in order to translate raw sensor measurements into human actions. The proposed pipeline is employed to automatically extract models to be reused for ambient intelligence. In this paper, we present an user evaluation aimed at demonstrating the effectiveness of the approach, by comparing it wrt. a relevant state-of-the-art visual tool, namely SITUVIS