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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]

Abstract: Software engineering research is driven by the aim of making software development more dynamic, flexible and evolvable. Nowadays the emphasis is on the evolution of pre-existing sub-systems and component and service-based development, where often only a part of the system is totally under control of the designer, most components being remotely operated by external vendors. In this context, we tackle the following problem: given the formal specification of the (incomplete) system, say it , already built, how to characterize collaborators of to be selected, based on a given communication interface , so that a given property is satisfied. Using properties described by temporal logic formulae and systems by CCS processes, if is the formula to be satisfied by the complete system, an efficient and automatic procedure is defined to identify a formula such that, for each existing process satisfying , the process satisfies . Important features of this result are simplicity of the derived property , compared to the original one, and scalability of the verification process. Such characteristics are necessary for applying the method to both incremental design and system evolution scenarios where is already in place, and one needs to understand the specification of the functionality of the new component that should correctly interact with . Indeed, in general, finding a suitable partner for is easier than finding a complete system satisfying the global property. Moreover, in this paper it is shown how can be used also to select a set of possible candidate processes through a property-directed and structural heuristic. From the verification point of view, the description of the lacking component through a logic formula guarantees correctness of the integration with of any process that exhibits a behaviour compliant with the inferred formula. [Copyright &y& Elsevier]

Abstract: In this paper, we present a formal model, named PobSAM (Policy-based Self-Adaptive Model), for developing and modeling self-adaptive evolving systems. In this model, policies are used as a mechanism to direct and adapt the behavior of self-adaptive systems. A PobSAM model is a collection of autonomous managers and managed actors. The managed actors are dedicated to the functional behavior while the autonomous managers govern the behavior of managed actors by enforcing suitable policies. A manager has a set of configurations including two types of policies: governing policies and adaptation policies. To adapt the system behavior in response to the changes, the managers switch among different configurations. We employ the combination of an algebraic formalism and an actor-based model to specify this model formally. Managed actors are expressed by an actor model. Managers are modeled as meta-actors whose configurations are described using a multi-sorted algebra called CA. We provide an operational semantics for PobSAM using labeled transition systems. Furthermore, we provide behavioral equivalence of different sorts of CA in terms of splitting bisimulation and prioritized splitting bisimulation. Equivalent managers send the same set of messages to the actors. Using our behavioral equivalence theory, we can prove that the overall behavior of the system is preserved by substituting a manager by an equivalent one. [Copyright &y& Elsevier]

Abstract: In order to cope with the increasing complexity of system design, component-based software engineering advocates the reuse and adaptation of existing software components. However, many applications—particularly embedded systems—consist of not only software, but also hardware components. Thus, component-based design should be extended to systems with both hardware and software components. Such an extension is not without challenges though. The extended methodology has to consider hard constraints on performance as well as different cost factors. Also, the dissimilarities between hardware and software (such as level of abstraction, communication primitives, etc.) have to be resolved. In this paper, the authors propose such an extended component-based design methodology to include hardware components as well. This methodology allows the designer to work at a very high level of abstraction, where the focus is on functionality only. Non-functional constraints are specified in a declarative manner, and the mapping of components to hardware or software is determined automatically based on those constraints in the so-called hardware/software partitioning step. Moreover, a tool is presented supporting the new design methodology. Beside automating the partitioning process, this tool also checks the consistency between hardware and software implementations of a component. The authors also present a case study to demonstrate the applicability of the outlined concepts. [Copyright &y& Elsevier]