Long-Term Average Cost in Featured Transition Systems

A software product line is a family of software products that share a common set of mandatory features and whose individual products are differentiated by their variable (optional or alternative) features. Family-based analysis of software product lines takes as input a single model of a complete product line and analyzes all its products at the same time. As the number of products in a software product line may be large, this is generally preferable to analyzing each product on its own. Family-based analysis, however, requires that standard algorithms be adapted to accomodate variability. In this paper we adapt the standard algorithm for computing limit average cost of a weighted transition system to software product lines. Limit average is a useful and popular measure for the long-term average behavior of a quality attribute such as performance or energy consumption, but has hitherto not been available for family-based analysis of software product lines. Our algorithm operates on weighted featured transition systems, at a symbolic level, and computes limit average cost for all products in a software product line at the same time. We have implemented the algorithm and evaluated it on several examples

Systems and Cost Effectiveness Modeling of Unmanned Systems Product Lines for Acquisition

Excerpt from the Proceedings of the Nineteenth Annual Acquisition Research SymposiumThis research investigated the systems and cost-effectiveness of unmanned system product lines to improve both the acquisition processes and warfighter's capabilities. Historically defined as the probability that a system can successfully meet an operational demand within a given time when operated under specified conditions, system effectiveness is the ability of a system to do its intended job. Traditionally applied to a single system acquiring DoD systems with overlapping capabilities are most economically acquired as integrated product lines. Therefore, more relevant measures are needed to evaluate product lines and similar systems of systems. Cost-effectiveness measures a system in terms of the cost of system effectiveness and its ability to fulfill the intended mission and total lifecycle cost (LCC). The LCC can be expressed in different ways depending upon specific mission or system parameters under evaluation. The "constructive product line investment model framework" (COPLIMO) applies to performing product line cost estimation and investment analysis. Initially oriented for software product line development, it is now a general framework for system product lines consisting of software, hardware, or combined elements. The Cost model is adaptable for different product types, processes, and estimation relationships necessary to cover unmanned systems. The cost model accomplishes this by employing product-specific parametric cost models to improve estimation fidelity versus using average assumptions. The overall model sums the software and hardware component estimates derived from their detailed cost models. The results of a student capstone report are the focal point of the paper.Approved for public release; distribution is unlimited

Quantitative Analysis of Probabilistic Models of Software Product Lines with Statistical Model Checking

We investigate the suitability of statistical model checking techniques for analysing quantitative properties of software product line models with probabilistic aspects. For this purpose, we enrich the feature-oriented language FLan with action rates, which specify the likelihood of exhibiting particular behaviour or of installing features at a specific moment or in a specific order. The enriched language (called PFLan) allows us to specify models of software product lines with probabilistic configurations and behaviour, e.g. by considering a PFLan semantics based on discrete-time Markov chains. The Maude implementation of PFLan is combined with the distributed statistical model checker MultiVeStA to perform quantitative analyses of a simple product line case study. The presented analyses include the likelihood of certain behaviour of interest (e.g. product malfunctioning) and the expected average cost of products.Comment: In Proceedings FMSPLE 2015, arXiv:1504.0301

Colored model based testing for software product lines (CMBT-SWPL)

Over the last decade, the software product line domain has emerged as one of the mostpromising software development paradigms. The main benefits of a software product lineapproach are improvements in productivity, time to market, product quality, and customersatisfaction.Therefore, one topic that needs greater emphasis is testing of software product lines toachieve the required software quality assurance. Our concern is how to test a softwareproduct line as early as possible in order to detect errors, because the cost of error detectedIn early phases is much less compared to the cost of errors when detected later.The method suggested in this thesis is a model-based, reuse-oriented test technique calledColored Model Based Testing for Software Product Lines (CMBT-SWPL). CMBT-SWPLis a requirements-based approach for efficiently generating tests for products in a soft-ware product line. This testing approach is used for validation and verification of productlines. It is a novel approach to test product lines using a Colored State Chart (CSC), whichconsiders variability early in the product line development process. More precisely, the vari-ability will be introduced in the main components of the CSC. Accordingly, the variabilityis preserved in test cases, as they are generated from colored test models automatically.During domain engineering, the CSC is derived from the feature model. By coloring theState Chart, the behavior of several product line variants can be modeled simultaneouslyin a single diagram and thus address product line variability early. The CSC representsthe test model, from which test cases using statistical testing are derived.During application engineering, these colored test models are customized for a specificapplication of the product line. At the end of this test process, the test cases are generatedagain using statistical testing, executed and the test results are ready for evaluation. Inxaddition, the CSC will be transformed to a Colored Petri Net (CPN) for verification andsimulation purposes.The main gains of applying the CMBT-SWPL method are early detection of defects inrequirements, such as ambiguities incompleteness and redundancy which is then reflectedin saving the test effort, time, development and maintenance costs

Trusted product lines

This thesis describes research undertaken into the application of software product line approaches to the development of high-integrity, embedded real-time software systems that are subject to regulatory approval/certification. The motivation for the research arose from a real business need to reduce cost and lead time of aerospace software development projects. The thesis hypothesis can be summarised as follows: It is feasible to construct product line models that allow the specification of required behaviour within a reference architecture that can be transformed into an effective product implementation, whilst enabling suitable supporting evidence for certification to be produced. The research concentrates on the following four main areas: 1. Construction of an argument framework in which the application of product line techniques to high-integrity software development can be assessed and critically reviewed. 2. Definition of a product-line reference architecture that can host components containing variation. 3. Design of model transformations that can automatically instantiate products from a set of components hosted within the reference architecture. 4. Identification of verification approaches that may provide evidence that the transformations designed in step 3 above preserve properties of interest from the product line model into the product instantiations. Together, these areas form the basis of an approach we term “Trusted Product Lines”. The approach has been evaluated and validated by deployment on a real aerospace project; the approach has been used to produce DO-178B/ED-12B Level A applications of over 300 KSLOC in size. The effect of this approach on the software development process has been critically evaluated in this thesis, both quantitatively (in terms of cost and relative size of process phases) and qualitatively (in terms of software quality). The “Trusted Product Lines” approach, as described within the thesis, shows how product line approaches can be applied to high-integrity software development, and how certification evidence created and arguments constructed for products instantiated from the product line. To the best of our knowledge, the development and effective application of product line techniques in a certification environment is novel and unique

Testing variability-intensive systems using automated analysis: an application to Android

Software product lines are used to develop a set of software products that, while being different, share a common set of features. Feature models are used as a compact representation of all the products (e.g., possible configurations) of the product line. The number of products that a feature model encodes may grow exponentially with the number of features. This increases the cost of testing the products within a product line. Some proposals deal with this problem by reducing the testing space using different techniques. However, a daunting challenge is to explore how the cost and value of test cases can be modeled and optimized in order to have lower-cost testing processes. In this paper, we present TESting vAriAbiLity Intensive Systems (TESALIA), an approach that uses automated analysis of feature models to optimize the testing of variability-intensive systems. We model test value and cost as feature attributes, and then we use a constraint satisfaction solver to prune, prioritize and package product line tests complementing prior work in the software product line testing literature. A prototype implementation of TESALIA is used for validation in an Android example showing the benefits of maximizing the mobile market share (the value function) while meeting a budgetary constraint.Ministerio de Economía y Competitividad TIN2012-32273Junta de Andalucía TIC-5906Junta de Andalucía TIC-186

A Configuration Management System for Software Product Lines

Software product line engineering (SPLE) is a methodology for developing a family of software products in a particular domain by systematic reuse of shared code in order to improve product quality and reduce development time and cost. Currently, there are no software configuration management (SCM) tools that support software product line evolution. Conventional SCM tools are designed to support single product development. The use of conventional SCM tools forces developers to treat a software product line as a single software project by introducing new programming language constructs or using conditional compilation. We propose a research conguration management prototype called Molhado SPL that is designed specifically to support the evolution of software product lines. Molhado SPL addresses the evolution problem at the configuration level instead of at the code level. We studied the type of operations needed to support the evolution of software product lines and proposed a versioning model and eight cases of change propagation. Molhado SPL supports independent evolution of core assets and products, the sharing of code and the tracking relationships between products and shared code, and the eight cases of change propagation. The Molhado SPL consists of four layers with each layer providing a different type of service. At the heart of Molhado SPL are the versioning model, component object, shared component object, and project objects that allow for independent evolution of products and shared artifacts, for sharing, and for supporting change propagation. Furthermore,they allow product specific changes to shared code without interfering with the core asset that is shared. Products can also introduce product specific assets that only exist in that product. In order to for Molhado SPL to support product line, we implemented XML merging, feature model editing and debugging, and version-aware XML documents. To support merging of XML documents, we implemented a 3-way XML document merging algorithm that uses versioned data structures, change detection, and node identity. To support software product line derivation or modeling of software product line, we implemented support for feature model including editing and debugging. Finally, we created the version-aware XML document framework to support collaborative editing of XML documents without requiring a version repository. The version history is embedded in the documents using XML namespaces, so that the documents remain valid under the XML specification. The version-aware XML framework can also be used to support the exporting of documents from Molhado SPL repository to be edit outside and import back the change history made to the document. We evaluated Molhado SPL with two product lines: a document product line and a the graph data structures product line. This evaluation showed that Molhado SPL supports independently evolution of products and core assets and the eight change propagation cases. We did not evaluate MolhadoSPL in terms of scalability or usability. The main contributions of this dissertation research are: 1) Molhado SPL that supports the evolution of product lines, 2) a fast 3-way XML merge algorithm, 3) a version-aware XML document framework, and 4) a feature model editor and debugger

Business Models for ASP Marketplaces

ASP (Application Server Provider) marketplaces provide a fundamental alternative to the classical business model of software licensing. At this point, it is still unclear why and when customers prefer the ASP model over more traditional approaches. To make ASP more attractive, more knowledge about possible pricing and product strategies is needed. In this paper we describe different business models for ASP marketplaces. We first compare the cost structures of the classical licensing model with the new server-based approach. Then we illustrate how price and product differentiation may improve overall market efficiency. In particular, we show that by selling different software versions for different prices, ASP marketplaces may obtain near-optimal revenues with products that are relatively inexpensive, disaggregated, and customizable. Consumers can thus choose between a wide variety of product lines to fit their differing budgets and requirements

Naval Combat System Product Line Architecture Economics

Acquisition Research Program Sponsored Report SeriesSponsored Acquisition Research & Technical ReportsA Model-Based Systems Engineering (MBSE) approach has been developed at the Naval Postgraduate School that integrates parametric cost and product modeling methods for economic trade-off analysis of system product lines. The research assesses the economic consequences of DoD product line options and has been refining a framework for others to use and adapt. This report provides details of the methodology and its application to several empirical case studies. The modeling framework includes a reference architecture and cost model for a general combat system product line that is extensible to other DoD and government domains. It has been applied to assess the economics of Navy combat system product line architecture approaches in coordinated case studies. The case studies were performed for a three-tier cruise missile system, the Aegis ship software product line, and an Anti-Submarine Warfare (ASW) cross-domain product line architecture for air, surface, and sub-surface applications. An overall business case analysis for DoD product line practices was performed synthesizing the case studies with recommendations generated.Approved for public release; distribution is unlimited.Approved for public release; distribution is unlimited

Review of Requirement Engineering Approaches for Software Product Lines

The Software Product Lines (SPL) paradigm is one of the most recent topics of interest for the software engineering community. On the one hand, the Software Product Lines is based on a reuse strategy with the aim to reduce the global time-to-market of the software product, to improve the software product quality, and to reduce the cost. On the other hand, traditional Requirement Engineering approaches could not be appropriated to deal with the new challenges that arises the SPL adoption. In the last years, several approaches have been proposed to cover this limitation. This technical report presents an analysis of specific approaches used in the development of SPL to provide solutions to model variability and to deal with the requirements engineering activities. The obtained results show that most of the research in this context is focused on the Domain Engineering, covering mainly the Feature Modeling and the Scenario Modeling. Among the studied approaches, only one of them supported the delta identification; this fact implies that new mechanisms to incorporate new deltas in the Domain specification are needed. Regarding the SPL adoption strategy, most of the approaches support a proactive strategy. However, this strategy is the most expensive and risk-prone. Finally, most of the approaches were based on modeling requirements with feature models giving less support to other important activities in the requirements engineering process such as elicitation, validation, or verification of requirements. The results of this study provide a wide view of the current state of research in requirements engineering for SPL and also highlight possible research gaps that may be of interest for researchers and practitioners.Blanes Domínguez, D.; Insfrán Pelozo, CE. (2011). Review of Requirement Engineering Approaches for Software Product Lines. http://hdl.handle.net/10251/1023