OPLA-tool

The Product Line Architecture (PLA) can be improved by taking into account key factors such as feature modularization, and by continuously evaluating its design according to metrics. Search-Based Software Engineering (SBSE) principles can be used to support an informed-design of PLAs. However, existing search-based design works address only traditional software design not considering intrinsic Software Product Line aspects. This paper presents MOA4PLA, a search-based approach to support the PLA design. It gives a multi-objective treatment to the design problem based on specific PLA metrics. A metamodel to represent the PLA and a novel search operator to improve feature modularization are proposed. Results point out that the application of MOA4PLA leads to PLA designs with well modularized features, contributing to improve features reusability and extensibility. It raises a set of solutions with different design trade-offs that can be used to improve the PLA design.

The architectural properties of product‐line architecture (PLA) design have been successfully optimised by multi‐objective genetic algorithms (GAs). Memetic algorithms (MAs) extend GA by adding a local search after the global search process. MA outperformed GA in the context of class modelling, software testing and the next release problem. However, no studies on the application of MAs for PLA design optimisation were found in the literature. In light of this, the authors performed an exploratory study, where MA was used to apply design patterns for a search‐based PLA design (SBPD) and achieved promising results. From the obtained results, they adjusted the MA‐based implementation. This study aims at investigating if the MA is more profitable to SBPD than GAs. Two empirical studies that involve four PLA designs were carried out for this task by varying the pair of objective functions. Empirical results show that MA achieved satisfactory solutions, despite being influenced by the original PLA design.

Search-Based Software Engineering (SBSE) tools offer automatic support by applying search-based techniques to solve different optimization problems of various software engineering areas. However, configuring SBSE tools often requires expertise in optimization techniques, posing a significant barrier for non-specialist users. This task involves selecting suitable algorithms, tuning parameters, choosing appropriate objective functions and search operators, and making decisions that affect optimization quality and performance. To address this challenge, we propose a multiple-LLM approach that integrates Large Language Models (LLMs), specifically ChatGPT-4, into SBSEworkflows to provide context-aware and natural language suggestions for parameter configuration. The approach follows a Divide and Conquer strategy, in which specialized LLMs are trained for distinct parameter configuration subproblems. As a proof of concept, we implemented OPLA-Wizard that works with OPLA-Tool v2.0, for Product Line Architecture (PLA) design. This assistant supports users in configuring algorithm settings, search operators, and objective functions through a user-friendly interface. Preliminary results show that the multiple-LLM approach improves accuracy, explanation clarity, and output format adherence compared to a single-LLM approach. This work contributes to the democratization of SBSE by reducing cognitive load, preventing misconfigurations, and making advanced optimization techniques more accessible to a broader audience.

Search-based algorithms have been successfully employed in Product Line Architecture (PLA) design in the seminal approach named Multi-Objective Approach for Product-Line Architecture Design (MOA4PLA). This approach generates a set of alternative PLA designs, which optimize different architectural properties. In addition to these properties, the alternative PLA designs should have as few architectural smells as possible. Architectural smells can negatively impact PLA variability, PLA extensibility, SPL maintainability, and other non-functional attributes. However, one of the main findings of a previous study is that the tool that automates the application of MOA4PLA adversely introduces architectural smells in the automatically generated solutions. In this work, we present OPLA-Tool-ASP, which is a tool that implements guidelines to detect and prevent the architectural smells Unused Interface, Unused Brick, Concern Overload, and Link Overload in the context of MOA4PLA. An empirical study was carried out to assess the effectiveness of OPLA-Tool-ASP in preventing the aforementioned smells in the resulting PLA designs. The obtained results pointed out that the proposed tool is effective in both preventing the smells and improving the architectural properties selected for optimization.

Software Product Lines (SPLs) is a reuse approach in which a family of products is generalized in a common architecture that can be adapted to different clients. The Product Line Architecture (PLA) is one of the most important artifacts of a SPL. PLA design requires great human effort as it involves several factors that are usually in conflict. To ease this task, PLA design can be formulated as an optimization problem with many factors, i.e, as a multi-objective optimization problem. In this context, the MOA4PLA approach was proposed to optimize PLA design using search algorithms and metrics specific to the context. This approach supported by OPLA-Tool has already been used in several works demonstrating its applicability. However, MOA4PLA does not take into account aspects that are subjective, such as the preferences of a particular Decision Maker (DM). To do so, this paper presents a proposal to incorporate the user preferences in the optimization process performed by MOA4PLA, through an interactive process in which the DM subjectively evaluates the solutions in processing time. Thus, the solutions generated can be better suited to the DM's needs or preferences. In order to allow the user interaction, modifications were made in MOA4PLA and implemented in the OPLA-Tool. Aiming at an initial validation of the proposal, an exploratory study was carried out, composed of two experiments: a qualitative and a quantitative. These experiments were realized with the participation of a software architect. Empirical results pointed out that the proposed interactive process enables the generation of PLAs that are in accordance with the architect's preferences. Another significant contribution are the lessons learned on how to improve the interactive process.

Microservice has been successfully employed in software industry [1, 11], as they provide modularization and easy management of small and autonomous services, high availability, scalability and short time-to-market. A recent study on microservices shows that most studies generate specific solutions, which emphasize the need for fundamental research, proposals of reusable practices and works that focus on providing information to ease communication between architects and stakeholders [11] -- software architecture can be a powerful tool for this regard. The definition and documentation of the software product line architecture (PLA) is an important activity, especially for inception and extraction of microservice-oriented PLA, because they involve decisions about how to design customizable microservices, how to arrange the communication between microsservices and APIs, etc. In this work, it is proposed a metamodel for the specification of microsserve-oriented PLA design in order to assist the developer in carrying out such an activity. The proposed metamodel was validated in an exploratory study, in which a new PLA was designed through the instantiation of the proposed metamodel and a product was configured from the designed PLA. Both the metamodel and its instantiation were evaluated in a survey involving software developers. The results indicate that the metamodel addresses the structural needs of microservice-oriented architectures. The main contributions of this work are (i) to assist the software product line developers in the specification and documentation of microservice-oriented PLA design and (ii) the lessons about the industrial practice learned from the surveys that are useful to enhance the proposed metamodel.

This paper addresses the problem of supporting usability in the early stages of a product line architecture design. The product line used as an example is intended to support a variety of different products each with a radically different user interface. The development cycles for new products varies between three years and five years and usability is valued as an important quality attribute for each product in the line.Traditionally, usability is achieved in a product by designing according to specific usability guidelines, and then performing user tests. User interface design can be performed separately from software architecture design and prototyping, but user tests cannot be performed before detailed UI design and prototyping. If the user tests discover usability problems leading to required architectural changes, the company would not know about this until two years after the architecture design was complete. This problem was addressed by identifying a collection of 19 well known usability scenarios that require architectural support. In our example, the stakeholders for the product line prioritized three of these scenarios as key product-line scenarios for improving usability. For each of these three chosen product-line scenarios we developed an architectural responsibility pattern that provided support for the scenario. The responsibilities are expressed in terms of architectural requirements with implementation details and rationales. The responsibilities were embodied in a web based tool for the architects.The two architects for the product line developed a preliminary design and then reviewed their design against the responsibilities supporting the scenarios. The process of review took a day and the architects conservatively estimated that it saved them five weeks of effort later in the project.

In automotive system design, system architects increasingly use model-based approaches for defining product line architectures (PLAs). This trend is strongly supported by the emergence of domain standards like EAST-ADL and AUTOSAR that facilitate a system design approach based on systematic reuse. In our work, we focus on the automated exploration of PLA design spaces by means of multi-objective optimization and ask what are challenges that stakeholders face as part of this design task. Optimizing PLA design spaces shares certain challenges with conventional architecture optimization, like conflicting quality goals and potentially vast design spaces. However, PLA optimization exacerbates these challenges by an additional layer of complexity in the system architecture, due to product line variability in the system. Our main focus in this paper is on achieving a better understanding of the stakeholder requirements on a support infrastructure for automated PLA design space exploration based on PLA system models. We also address the challenges that stakeholders must overcome when integrating such an approach into an existing process landscape. For that purpose, we conducted a study with automotive industry experts and analyzed the findings using the qualitative data analysis methods of Grounded Theory. Based on the study results, we derive a set of challenges for the realization and integration of automated and semi-automated PLA design space exploration in industrial environments.

Search-based software engineering (SBSE) consists of the application of metaheuristic search techniques—such as genetic algorithms, simulated annealing, hill climbing, and tabu search—to software engineering problems. This idea is based on the observation that some software engineering activities can be thought of as optimization problems, and on the fact that techniques providing exact solutions are, very often, unable to adequately scale to large, real-world software engineering problems. Define fitness functions to guide an automated search for solutions, rather than attempting to construct solutions from scratch by hand. SBSE moves the engineer up the abstraction chain, from the tedious and expensive role of detailed solution construction, to the potentially more productive and more cost-effective area of fitness function design. This approach has been repeatedly demonstrated to have successful applications across the software engineering life cycle from requirements and project planning to maintenance and testing. This special issue focuses on applications of search SBSE to the maintenance phase of the life cycle. After software testing 2, software maintenance is the most widely studied application area for SBSE research. Work on SBSE applications to problems in software maintenance can be traced back to the pioneering work of the Mancoridis et al. 3, which led to the development of the Bunch tool for software re-modularization 4. In the past five years there has been a significant increase in SBSE applications to software maintenance and evolution. Search-based techniques have been applied to post-development code improvement problems, such as object-oriented refactoring 5, 6, and imperative language slicing and transformation 7. Other applications are related to software engineering economics and project management problems, such as release planning 8-12, effort, and cost estimation 13-16, and project staffing and planning 17-20. Last, but not the least, SBSE has been applied to deal with service-oriented architectures, for example for services QoS-aware composition 21, service-level agreement negotiation 22, and testing 23. A complete overview of SBSE with a discussion of future research trends can be found in the recent International Conference on Software Engineering (ICSE) ‘Future of Software Engineering’ paper 24. This issue of the Journal of Software Maintenance and Evolution: Research and Practice features three outstanding papers, dealing with different aspects of software maintenance and evolution: release planning and staffing, re-factoring, and component substitution. The paper ‘Optimized Staffing for Product Releases—Focused Search and its Application at Chartwell Technologies’ by Puneet Kapur, An Ngo-The, Günther Ruhe, and Andrew Smith presents an approach for optimizing the staffing for product releases. The problem they solve can be viewed as part of the more general release planning problem, which assigns features to releases such that technical, resource, risk, and budget constraints are met. In particular, the genetic search-based approach the authors propose aims at assigning human resources to software development tasks, taking them from a pool of developers having different levels of skills. The applicability of the proposed approach is demonstrated with an industrial case study. The paper ‘Search-Based Refactoring: an Empirical Study’ by Mark O'Keffe and Mel Ó Cinnéide presents an approach to automatically re-factor, using search-based techniques, object-oriented systems that undergo repeated addition of functionality. Such addition can, very often, deteriorate the quality of the system's underlying design. Their re-factoring is guided by the QMOOD quality model 25, and the paper compares different optimization techniques, such as Genetic Algorithms, Simulated Annealing, and Multiple Ascent Hill-Climbing. The results of experiments carried out on five software systems suggest that the latter technique outperforms the others. The paper ‘Search-based Many-to-one Component Substitution’ by Nicolas Desnos, Marianne Huchard, Guy Tremblay, Christelle Urtado, and Sylvain Vauttier presents a search-based approach that allows the replacement of an obsolete component with a composition of multiple components. When a component becomes obsolete, the approach searches for a minimal assembly of other components, exposing their functionality by means of ports that preserves the behavior of the original component. The proposed approach has been evaluated on a set of randomly generated components. We hope that readers will enjoy this special issue and find the selected papers insightful and inspiring. We would like to thank all the authors who presented papers for this special issue: there were many good quality papers, but unfortunately we could accept only three of them. Last, but not the least, we would like to thank the reviewers who provided timely, detailed and constructive feedbacks to the authors. Without their precious help this special issue would not have been possible.

The application of design patterns through mutation operators in search-based design may improve the quality of the architectures produced in the evolution process. However, we did not find, in the literature, works applying such patterns in the optimization of Product Line Architecture (PLA). Existing works offer manual approaches, which are not search-based, and only apply specific patterns in particular domains. Considering this fact, this paper introduces a meta-model and a mutation operator to allow the design patterns application in the search-based PLA design. The model represents suitable scopes, that is, set of architectural elements that are suitable to receive a pattern. The mutation operator is used with a multi-objective and evolutionary approach to obtain PLA alternatives. Quantitative and qualitative analysis of empirical results show an improvement in the quality of the obtained solutions.

This special issue of Empirical Software Engineering consists of revised and extended versions of five selected papers originally presented at the 1st International Symposium on Search Based Software Engineering (SSBSE 2009). The symposium was held at Cumberland Lodge, Windsor, UK, in May 2009, and brought together the academic researchers and industrial practitioners that make up the international Search Based Software Engineering (SBSE) community for the first conference dedicated to the subject. Search Based Software Engineering is the application of search-based optimization techniques—for example, genetic algorithms, hill climbing, simulated annealing, taboo search, and ant colony optimization—to the solution of software engineering problems. Many such problems are often difficult or impossible to solve manually, and moreover, as modern software becomes more complex and adopts distributed and highly parallel architectures, are proving to be increasingly intractable using traditional automated techniques. In contrast, SBSE approaches can leverage sophisticated optimisation algorithms running on affordable computing infrastructure to solve these problems. SBSE approaches also demonstrate other advantages: they can be used to find acceptably good solutions when time, or resources, are limited, and—by utilizing multi-objective search algorithms—can derive a range of solutions that illustrate potential trade-offs between competing goals. For these reasons, both academic and industrial interest in SBSE is increasing rapidly. A recent survey,1 undertaken by the UK-based SEBASE project, indicated an exponential growth of

With the complexity of mechanical manufacturing system design increasing, the traditional single-objective optimization method can no longer meet the needs of multi-objective optimization, such as lightweight, high efficiency, low energy consumption and long life. Multi-objective optimization algorithm is widely used in mechanical design and manufacturing process planning because of its good convergence and diversity. Taking robot motion planning as an example, this paper analyzes the application methods of multi-objective optimization algorithm in mechanical structure design in detail, including problem description, multi-objective optimization model construction, algorithm application and performance analysis. Through the application of Genetic Algorithm (GA), this paper shows how the multi-objective optimization algorithm can balance multiple objectives such as path length, energy consumption and obstacle avoidance effect, and realize more intelligent and efficient solutions in robot motion planning. Performance analysis shows that GA is superior to single-objective optimization and random search algorithm in optimization effect, computational efficiency and stability. In addition, this paper also discusses the influence of the change of target weight and algorithm parameters on the optimization results, which provides valuable reference for future algorithm optimization and practical application. Multi-objective optimization algorithm shows obvious advantages in mechanical manufacturing system, which provides new ideas and methods for realizing more efficient, more environmentally friendly and more intelligent mechanical manufacturing design.

Battle Royale Optimizer (BRO) is a recently proposed optimization algorithm that has added a new category named game-based optimization algorithms to the existing categorization of optimization algorithms. Both continuous and binary versions of this algorithm have already been proposed. Generally, optimization problems can be divided into single-objective and multi-objective problems. Although BRO has successfully solved single-objective optimization problems, no multi-objective version has been proposed for it yet. This gap motivated us to design and implement the multi-objective version of BRO (MOBRO). Although there are some multi-objective optimization algorithms in the literature, according to the no-free-lunch theorem, no optimization algorithm can efficiently solve all optimization problems. We applied the proposed algorithm to four benchmark datasets: CEC 2009, CEC 2018, ZDT, and DTLZ. We measured the performance of MOBRO based on three aspects: convergence, spread, and distribution, using three performance criteria: inverted generational distance, maximum spread, and spacing. We also compared its obtained results with those of three state-of-the-art optimization algorithms: the multi-objective Gray Wolf optimization algorithm (MOGWO), the multi-objective particle swarm optimization algorithm (MOPSO), the multi-objective artificial vulture's optimization algorithm (MOAVAO), the optimization algorithm for multi-objective problems (MAOA), and the multi-objective non-dominated sorting genetic algorithm III (NSGA-III). The obtained results approve that MOBRO outperforms the existing optimization algorithms in most of the benchmark suites and operates competitively with them in the others.

Product line engineering is a recent approach to software development that has shown to enable organizations to achieve significant reductions in development and maintenance cost as well as time-to-market of increasingly complex software systems. Yet, the testing process has not kept up with these reductions and the relative cost for testing product lines is actually becoming higher than in traditional single system development. Also, testing often cannot keep pace with accelerated development in product line engineering due to technical and organizational issues. This paper advocates that testing of product lines can be made more efficient and effective by considering testability already during architectural design. It explores the relationship between testability and product line architecture and discusses the importance of high testability for reducing product line testing effort and achieving required coverage criteria. The paper also outlines a systematic approach that will support product line organizations in improving and evaluating testability of product lines at the architectural level.

Various software engineering paradigms and real-time projects have proved that software testing is the most critical and highly important phase in the SDLC. In general, software testing takes approximately 40–60% of the total effort and time involved in project development. Generating test cases is the most important process in software testing. There are many techniques involved in the automatic generation of these test cases which aim to find a smaller group of cases that could allow for an adequacy level to be achieved which will hence reduce the effort and cost involved in software testing. In the structural testing of a product, the auto-generation of test cases that are path focused in an efficient manner is a challenging process. These are often considered optimization problems and hence search-based methods such as genetic algorithm (GA) and swarm optimizations have been proposed to handle this issue. The significance of the study is to address the optimization problem of automatic test case generation in search-based software engineering. The proposed methodology aims to close the gap of genetic algorithms acquiring local minimum due to poor diversity. Here, dynamic adjustment of cross-over and mutation rate is achieved by calculating the individual measure of similarity and fitness and searching for the more global optimum. The proposed method is applied and experimented on a benchmark of five industrial projects. The results of the experiments have confirmed the efficiency of generating test cases that have optimum path coverage.