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For two years, we have been involved in a challenging project to develop a new architecture for an industrial transportation system. The motivating quality attributes to develop this innovative architecture were flexibility and openness. Taking these quality attributes into account, we proposed a decentralized architecture using multiagent systems (MASs). A MAS consists of multiple autonomous entities that coordinate with each other to achieve decentralized control. The typical advantages attributed to such decentralized architecture are flexibility and openness, the motivating quality attributes to apply MAS in this case.The Architecture Tradeoff Analysis Method (ATAM) was used to provide insights wether our architecture meets the expected flexibility and openness, and to identify tradeoffs with other quality attributes. Applying the ATAM proved to be a valuable experience. One of the main outcome of applying the ATAM was the identification of a tradeoff between flexibility and communication load that results from the use of a decentralized architecture.This paper describes our experiences in applying the ATAM to a MAS architecture, containing both the main outcomes of the evaluation and a critical reflection on the ATAM itself.

Task assignment in multi-agent systems is a complex coordination problem, in particular in systems that are subject to dynamic and changing operating conditions. To enable agents to deal with dynamism and change, adaptive task assignment approaches are needed. In this paper, we study two approaches for adaptive task assignment that are characteristic for two classical families of task assignment approaches. FiTA is a field-based approach in which tasks emit fields in the environment that guide idle agents to tasks. DynCNET is a protocol-based approach that extends Standard Contract Net (CNET). In DynCNET, agents use explicit negotiation to assign tasks. We compare both approaches in a simulation of an industrial automated transportation system. Our experiences show that: (1) the performance of DynCNET and FiTA are similar, while both outperform CNET; (2) the complexity to engineer DynCNET is similar to FiTA but much more complex than CNET; (3) whereas task assignment with FiTA is an emergent solution, DynCNET specifies the interaction among agents explicitly allowing engineers to reason on the assignment of tasks, (4) FiTA is inherently robust to message loss while DynCNET requires substantial additional support. The tradeoff between (3) and (4) is an important criteria for the selection of an adaptive task assignment approach in practice.

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It is commonly agreed that an architectural description (AD) consists of multiple views. Each view describes the architecture from the perspective of particular stakeholder concerns. Although views are constructed separately, they are related as they describe the same system. A thorough study of the literature reveals that research on relations between views is fragmented and that a comprehensive study is hampered by an absence of common terminology. This has become apparent in the discussion on interview relational concepts in the revision of IEEE 1471 as ISO/IEC 42010 (Systems and Software Engineering-Architectural Description). This paper puts forward a framework that employs a consistent terminology to characterize relations between views. The framework sheds light on the usage, scope and mechanisms for relations, and is illustrated using several representative approaches from the literature. We conclude with a reflection on whether the revision of ISO 42010 aligns with our findings.

Architectural conformance checking verifies whether a system conforms to its intended architecture, which is essential to safeguard the quality attributes of the system. Due to the size of many systems, performing conformance checking by means of manual code inspections is often practically infeasible. Code analysis tools can be used to automatically check architectural conformance.In this paper, we investigate several code analysis tools that offer support for Java and compare them on their usefulness for architectural conformance checking: Architecture Rules, Macker, Lattix DSM, SonarJ, Structure101 and XDepend.

Architectural views are at the foundation of software architecture and are used to describe the system from different perspectives. However, some architectural concerns crosscut the decomposition of the architecture in views. The drawbacks of crosscutting with respect to architectural views is similar to the drawbacks with respect to code, i.e. hampering reuse, maintenance and evolution. This paper investigates the relations between architectural concerns and views to identify why concerns tend to crosscut. We propose to extend the architectural description with slices and composition mechanisms to prevent this crosscutting and perform an initial exploration of these concepts in an Online Auction system. Within this limited setting the first results look promising to better separate concerns that otherwise would crosscut the views.

Despite the successes of software product lines (SPL), managing the evolution of a SPL remains difficult and error-prone. Our focus of evolution is on the concrete tasks integrators have to perform to update deployed SPL products, in particular products that require runtime updates with minimal interruption. The complexity of updating a deployed SPL product is caused by multiple interdependent concerns, including variability, traceability, versioning, availability, and correctness. Existing approaches typically focus on particular concerns while making abstraction of others, thus offering only partial solutions. An integrated approach that takes into account the different stakeholder concerns is lacking. In this paper, we present an architectural approach for updating SPL products that supports multiple concerns. The approach comprises of two complementary parts: (1) an update viewpoint that defines the conventions for constructing and using architecture views to deal with multiple update concerns; and (2) a supporting framework that provides an extensible infrastructure supporting integrators of a SPL. We evaluated the approach for an industrial SPL for logistic systems providing empirical evidence for its benefits and recommendations.