Timed I/O Automata: It is never too late to complete your timed specification theory

A specification theory combines notions of specifications and implementations with a satisfaction relation, a refinement relation and a set of operators supporting stepwise design. We develop a complete specification framework for real-time systems using Timed I/O Automata as the specification formalism, with the semantics expressed in terms of Timed I/O Transition Systems. We provide constructs for refinement, consistency checking, logical and structural composition, and quotient of specifications -- all indispensable ingredients of a compositional design methodology. The theory is backed by rigorous proofs and is being implemented in the open-source tool ECDAR.Comment: Version submitted for revie

AUTSEG: Automatic Test Set Generator for Embedded Reactive Systems

Part 2: Tools and FrameworksInternational audienceOne of the biggest challenges in hardware and software design is to ensure that a system is error-free. Small errors in reactive embedded systems can have disastrous and costly consequences for a project. Preventing such errors by identifying the most probable cases of erratic system behavior is quite challenging. In this paper, we introduce an automatic test set generator called AUTSEG. Its input is a generic model of the target system, generated using the synchronous approach. Our tool finds the optimal preconditions for restricting the state space of the model. It only works locally on significant subspaces. Our approach exhibits a simpler and efficient quasi-flattening algorithm than existing techniques and a useful compiled form to check security properties and reduce the combinatorial explosion problem of state space. To illustrate our approach, AUTSEG was applied to the case of a transportation contactless card

Automated reasoning on feature models

Software Product Line (SPL) Engineering has proved to be an effective method for software production. However, in the SPL community it is well recognized that variability in SPLs is increasing by the thousands. Hence, an automatic support is needed to deal with variability in SPL. Most of the current proposals for automatic reasoning on SPL are not devised to cope with extra– functional features. In this paper we introduce a proposal to model and reason on an SPL using constraint programming. We take into account functional and extra–functional features, improve current proposals and present a running, yet feasible implementation

Timing and spatial distribution of deformation in the Newfoundland Appalachians: a "multi-stage collision" history

The Newfoundland Appalachians have been interpreted as an area where Lower Paleozoic plate convergence culminated in collision between an Ordovician volcanic chain and the North American craton hi Middle Ordovician times. Closure of the intervening proto-Atlantic (Iapetus) ocean was considered incomplete. Subsequent deformation gave rise to regional folding and faulting.Recent studies in the Newfoundland Dunnage zone have revealed that the deformation history is far more complex than previously recognized. Large-scale thrusting, folding and faulting occurred in Silurian-Devonian times. Furthermore, it has been suggested that the Dunnage zone is an allochthonous terrane underlain by dominantly continental crust rather than representing remnants of a "rooted" ocean basin.In view of these results a revision of tectonic scenarios and zonal subdivision is warranted and a "multi-stage collision" history will be discussed, with emphasis on the spatial distribution and significance of Silurian-Devonian deformation in central Newfoundland.Subduction in Lower Paleozoic times gave rise to the formation of a volcanic terrane; concurrently, to the southeast a marginal sea was formed (Mariana-type subduction). In Middle Ordovician times the volcanic terrane collided with the North American craton ("first-stage collision") and back-arc spreading terminated. Continued crustal shortening resulted in the formation of a Silurian accretionary terrane (telescoped marginal sea), and its subsequent deformation ("second-stage collision"). Devonian (-Carboniferous?) strike-slip faulting represents the third stage in the collision history.The model is applicable to large tracts of the Caledonian-Appalachian chain. Its main characteristics are: 1. (a) the revised zonal subdivision of the area is based on characteristics of Silurian and older rocks, rather than Middle Ordovician and older rocks only;2. (b) the central part of the orogen represents a telescoped marginal sea that formed to the southeast of the Ordovician volcanic chain, rather than a remnant of the incompletely closed Iapetus ocean;3. (c) the earliest deformation is progressively younger toward the southeast;4. (d) the Appalachian collision history is a result of the activity of a single deformation regime over a long period of at least 75 Ma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26738/1/0000289.pd

20 Years of Mixed and Modal Specifications

Twenty years ago, modal and mixed specifications were proposed as abstract models of system behavior. In this paper, we explain the nature and utility of such specifications, relate them to other formalisms, showcase some of their established applications, and mention some existing tool support. We also present some recent complexity results for decision problems underlying such applications and list some remaining open problems