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Abstract Many metrics have been proposed to measure coupling—the degree of association between modules in a system. They have often been described in different ways, hindering comparison and research. Their definitions are often incomplete regarding language features in some languages, meaning that different tool developers may implement the same metric differently. This complicates comparing results from studies that use different tools. This paper therefore aims to define coupling metrics consistently and unambiguously. The paper describes a model of coupling that uses the reification of the concept of dependency as its fundamental unit. Based on this model, it defines a framework for defining coupling metrics. It shows how to define several well-known coupling metrics in the framework, and how defining different metrics based on the same model facilitates direct comparisons. It discusses how the framework resolves issues due to incomplete metric definitions, such as different language features. This formal framework is sufficiently simple that it can be implemented in such a way as to provide multiple metrics. [ABSTRACT FROM AUTHOR]

Fuzzy Switch Graphs (FSG) generalize the notion of Fuzzy Graphs by adding high-order arrows and aggregation functions which update the fuzzy values of arrows whenever a zero-order arrow is crossed. In this paper, we propose a more general structure called Reversal Fuzzy Switch Graph (R F S G), which promotes other actions in addition to updating the fuzzy values of the arrows, like activation and deactivation of the arrows. R F S G s are able to model dynamical aspects of some systems which generally appear in engineering, computer science and some other fields. The paper also provides the relationship between R F S G s and fuzzy graphs, a logic to verify properties of the modeled system and closes with an application. • Fuzzy logic and aggregation functions are used to specify reactive systems. • Fuzzy Reactive Switch Graphs generalize the notion of fuzzy graphs. • Bisimulation of reactive systems is threated in this system. • An example of a control system is provided for Fuzzy Reactive Switch Graphs. [ABSTRACT FROM AUTHOR]

Abstract: Measuring inconsistency is crucial to effective inconsistency management in software development. A complete measurement of inconsistency should focus on not only the degree but also the significance of inconsistency. However, most of the approaches available only take the degree of inconsistency into account. The significance of inconsistency has not yet been given much needed consideration. This paper presents an approach for measuring the significance of inconsistency arising from different viewpoints in the Viewpoints framework. We call an individual set of requirements belonging to different viewpoints a combined requirements collection in this paper. We argue that the significance of inconsistency arising in a combined requirements collection is closely associated with global priority levels of requirements involved in the inconsistency. Here we assume that the global priority level of an individual requirement captures the relative importance of every viewpoint including this requirement as well as the local priority level of the requirement within the viewpoint. Then we use the synthesis of global priority levels of all the requirements in a combined collection to measure the significance of the collection. Following this, we present a scoring matrix function to measure the significance of inconsistency in an inconsistent combined requirements collection, which describes the contribution made by each subset of the requirements collection to the significance of the set of requirements involved in the inconsistency. An ordering relationship between inconsistencies of two combined requirements collections, termed more significant than, is also presented by comparing their significance scoring matrix functions. Finally, these techniques were implemented in a prototype tool called IncMeasurer, which we developed as a proof of concept. [Copyright &y& Elsevier]

Abstract: This paper provides a sound foundation for autonomous objects communicating by remote method invocations and futures. As a distributed extension of -calculus we define ASPfun, a calculus of functional objects, behaving autonomously and communicating by a request-reply mechanism: requests are method calls handled asynchronously and futures represent awaited results for requests. This results in an object language enabling a concise representation of a set of active objects interacting by asynchronous method invocations. This paper first presents the ASPfun calculus and its semantics. Then, we provide a type system for ASPfun which guarantees the “progress” property. Most importantly, ASPfun has been formalised; its properties have been formalised and proved using the Isabelle theorem prover and we consider this as an important step in the formalization of distributed languages. This work was also an opportunity to study different binder representations and experiment with two of them in the Isabelle/HOL theorem prover. [Copyright &y& Elsevier]

Abstract: Over the past years, the need for high-confidence coordination mechanisms has intensified as new technologies have appeared for the development of service-oriented applications, making formalization of coordination mechanisms critical. Unifying Theories of Programming (UTP) provide a formal semantic foundation not only for programming languages but also for various expressive specification languages. A key concept in UTP is design: the familiar pre/post-condition pair that describes a contract. In this paper we use UTP to formalize Reo connectors, whereby connectors are interpreted as designs in UTP. This model can be used as a semantic foundation for proving properties of connectors, such as equivalence and refinement relations between connectors. Furthermore, it can be used as a reference document for developing tool support for Reo, such as test case generators. A fault-based method to generate test cases for component connectors from specifications is also provided in this paper. For connectors, faults are caused by possible errors during the development process, such as wrongly used channels, missing or redundant subcircuits, or circuits with wrongly constructed topology. We give test cases and connectors a unifying formal semantics by using the notion of design in UTP, and generate test cases by solving constraints obtained from a specification and a faulty implementation. A prototype serves to demonstrate the automatization of the approach. [Copyright &y& Elsevier]

Abstract Object-oriented programming is widely used in both the industry and the education areas. The most-common model of object-oriented programming is the class-based one. However, popular languages not implementing this model are gaining traction as time goes by. This alternative model is the prototype-based one, with one key characteristic: there are no classes. In this paper, a visual tool is proposed as a vehicle for learning the prototype-based object-oriented programming, present, for instance, in Self, Lua, or JavaScript. This software has been in use for three years in a subject of the Computer Science Engineering degree, at the University of Vigo. Highlights • Pooi is an interactive environment which updates with each instruction. • The system sports an diagram viewer, an object inspector, and a REPL. • The software was designed for undergraduate students of computer science engineering. • This tool has been used successfully in lecturing object-oriented programming. • Pooi is free, offering also the sources, and a set of tutorials and examples: http://jbgarcia.webs.uvigo.es/prys/pooi/. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, we applied and extended the theory of Abadi and Lamport (1991)  on the existence of refinement mappings. The present paper presents an overview of our extensions of the theory. For most concepts we provide examples or pointers to case studies where they occurred. The paper presents the results on semantic completeness. It sketches out how the theory is related to the other formalisms in the area. It discusses the tension between semantic completeness and methodological convenience. It concludes with our experience with the theorem provers NQTHM and PVS that were used during these projects. [Copyright &y& Elsevier]

Highlights • An architectural assumption management process with guidelines is developed. • Two case studies were conducted to validate the process. • The process can help to make architectural assumptions explicit. • The process can help to identify and reduce invalid architectural assumptions. Abstract Context Architectural assumption management is critical to the success of software development projects. In this paper, we propose an Architectural Assumption Management (AAM) process, comprised of four AAM activities: Architectural Assumption Making, Description, Evaluation, and Maintenance. Objective Evaluating the AAM process in architectural assumption management, regarding the ease of understanding and the effort of conducting the AAM process, as well as the effectiveness of using the AAM process to make architectural assumptions explicit and to identify and reduce invalid architectural assumptions. Method An explanatory study with 88 first-year master students in software engineering, and an exploratory study with five practitioners from five companies. Results (1) the ease of understanding the AAM process is moderate for first-year master students but easy for practitioners; (2) the effort of conducting the AAM process is moderate for first-year master students; (3) Making and Evaluation took the students more time than Description and Maintenance; (4) the practitioners considered Evaluation as the most time consuming activity; (5) the AAM process can help to make architectural assumptions explicit and to identify and reduce invalid architectural assumptions in projects. The majority of the students and practitioners agreed that Architectural Assumption Evaluation is the most helpful activity for all these three aspects. For other activities, there are different opinions about their helpfulness; and (6) there are various factors identified that can impact the aforementioned results. Being aware of and properly adjusting these factors can facilitate the application of the AAM process in projects. Conclusions The AAM process aims at systematically managing architectural assumptions in software development. The results of the case studies provide preliminary empirical evidence for the evaluation of the AAM process. [ABSTRACT FROM AUTHOR]

Optimizations performed by compilers, usually expressed as rewrites on program graphs, are a core part of modern compilers. However, even production compilers have bugs, and these bugs are difficult to detect and resolve. In this paper we present Morpheus, a domain-specific language for formal specification of program transformations, and describe its executable semantics. The fundamental approach of Morpheus is to describe program transformations as rewrites on control flow graphs with temporal logic side conditions. The syntax of Morpheus allows cleaner, more comprehensible specifications of program optimizations; its executable semantics allows these specifications to act as prototypes for the optimizations themselves, so that candidate optimizations can be tested and refined before going on to include them in a compiler. We demonstrate the use of Morpheus to state, test, and refine the specification of a variety of transformations, including a simple loop peeling transformation for single-threaded code and a redundant store elimination optimization on parallel programs. [ABSTRACT FROM AUTHOR]