State space c-reductions for concurrent systems in rewriting logic

We present c-reductions, a state space reduction technique. The rough idea is to exploit some equivalence relation on states (possibly capturing system regularities) that preserves behavioral properties, and explore the induced quotient system. This is done by means of a canonizer function, which maps each state into a (non necessarily unique) canonical representative of its equivalence class. The approach exploits the expressiveness of rewriting logic and its realization in Maude to enjoy several advantages over similar approaches: exibility and simplicity in the definition of the reductions (supporting not only traditional symmetry reductions, but also name reuse and name abstraction); reasoning support for checking and proving correctness of the reductions; and automatization of the reduction infrastructure via Maude's meta-programming features. The approach has been validated over a set of representative case studies, exhibiting comparable results with respect to other tools

Modelling and analyzing adaptive self-assembling strategies with Maude

Building adaptive systems with predictable emergent behavior is a challenging task and it is becoming a critical need. The research community has accepted the challenge by introducing approaches of various nature: from software architectures, to programming paradigms, to analysis techniques. We recently proposed a conceptual framework for adaptation centered around the role of control data. In this paper we show that it can be naturally realized in a reflective logical language like Maude by using the Reflective Russian Dolls model. Moreover, we exploit this model to specify and analyse a prominent example of adaptive system: robot swarms equipped with obstacle-avoidance self-assembly strategies. The analysis exploits the statistical model checker PVesta

An experimental analysis of the instability of non-axisymmetric liquid bridges in a gravitational field

he stability limits of nonaxisymmetric liquid bridges between equal in diameter, coaxial disks have been determined experimentally. Experiments have been performed by working with very small size liquid bridges. The experimental setup allows any orientation of the liquid bridge axis with respect to the local gravity vector acceleration. By appropriately orienting the liquid bridge axis, the influence on the stability limits of both the lateral and the axial component of the acceleration acting on the liquid bridge has been investigated

One-dimensional dynamics of nearly unstable axisymmetric liquid bridges

A general one-dimensional model is considered that describes the dynamics of slender, axisymmetric, noncylindrical liquid bridges between two equal disks. Such model depends on two adjustable parameters and includes as particular cases the standard Lee and Cosserat models. For slender liquid bridges, the model provides sufficiently accurate results and involves much easier and faster calculations than the full three-dimensional model. In particular, viscous effects are easily accounted for. The one-dimensional model is used to derive a simple weakly nonlinear description of the dynamics near the instability limit. Small perturbations of marginal instability conditions are also considered that account for volume perturbations, nonequality of the supporting disks, and axial gravity. The analysis shows that the dynamics breaks the reflection symmetry on the midplane between the supporting disks. The weakly nonlinear evolution of the amplitude of the perturbation is given by a Duffing equation, whose coefficients are calculated in terms of the slenderness as a part of the analysis and exhibit a weak dependence on the adjustable parameters of the one-dimensional model. The amplitude equation is used to make quantitative predictions of both the (first stage of) breakage for unstable configurations and the (slow) dynamics for stable configurations

Analysis of the feeding system in the injection process of peek in fixed partial dentures

[EN] In dental sector, PEEK is a new material used in the injection process of fixed partial dentures (FPD). The design of the feeding system is one of the most important stages in the injection process. This study simulates different locations of the feeding system in fixed partial dentures of PEEK, varying number of the injection points, using the software Moldflow. Variables used to compare simulations are the complete filling of the FPD mould cavity, the filling time, the minimum amount of rejected material of the feeding system, defects due to air traps, welding lines, etc. As results, depending on the geometric complexity, and the number and position of the injection points, it is possible to reduce the rejected material and to improve the filling time of the FPD.Gutiérrez, SC.; Meseguer, MD.; Gandía Barberá, A. (2015). Analysis of the feeding system in the injection process of peek in fixed partial dentures. Procedia Engineering. 132:1021-1028. doi:10.1016/j.proeng.2015.12.591S1021102813

A formal support to business and architectural design for service-oriented systems

Architectural Design Rewriting (ADR) is an approach for the design of software architectures developed within Sensoria by reconciling graph transformation and process calculi techniques. The key feature that makes ADR a suitable and expressive framework is the algebraic handling of structured graphs, which improves the support for specification, analysis and verification of service-oriented architectures and applications. We show how ADR is used as a formal ground for high-level modelling languages and approaches developed within Sensoria

Rewriting Logic Semantics of a Plan Execution Language

The Plan Execution Interchange Language (PLEXIL) is a synchronous language developed by NASA to support autonomous spacecraft operations. In this paper, we propose a rewriting logic semantics of PLEXIL in Maude, a high-performance logical engine. The rewriting logic semantics is by itself a formal interpreter of the language and can be used as a semantic benchmark for the implementation of PLEXIL executives. The implementation in Maude has the additional benefit of making available to PLEXIL designers and developers all the formal analysis and verification tools provided by Maude. The formalization of the PLEXIL semantics in rewriting logic poses an interesting challenge due to the synchronous nature of the language and the prioritized rules defining its semantics. To overcome this difficulty, we propose a general procedure for simulating synchronous set relations in rewriting logic that is sound and, for deterministic relations, complete. We also report on two issues at the design level of the original PLEXIL semantics that were identified with the help of the executable specification in Maude

Analysis of variability in the manufacture of Cr-Co fixed partial dentures by geometric comparison

[EN] This article studies tridimensional adjustment of Cr-Co fixed partial dentures obtained with different manufacturing processes (CNC milling, laser metal sintering and lost-wax), making a special point of the most critical adjustment, the marginal fit. A model was obtained with the impression taken in the oral cavity of a patient. This model was digitalized, and serves as the reference for manufacturing fixed partial dentures using different manufacturing processes. This article proposes a method of comparing the original model with the fixed partial dentures. This comparison was carried out using commercial software, allowing dental technicians to obtain information which can identify errors and geometric discrepancies before the fixed partial denture is implanted in the patient.Gutiérrez, SC.; Meseguer, MD.; Bellera Sosa, J.; Folguera Arbas, F. (2013). Analysis of variability in the manufacture of Cr-Co fixed partial dentures by geometric comparison. Procedia Engineering. 63:481-488. doi:10.1016/j.proeng.2013.08.270S4814886

Using indirect blockmodeling for monitoring students roles in collaborative learning networks

Collaborative learning activities have shown to be useful to address educational processes in several contexts. Monitoring these activities is mandatory to determine the quality of the collaboration and learning processes. Recent research works propose using Social Network Analysis techniques to understand students' collaboration learning process during these experiences. Aligned with that, this paper proposes the use of the indirect blockmodeling network analytic technique for monitoring the behaviour of different social roles played by students in collaborative learning scenarios. The usefulness of this technique was evaluated through a study that analysed the students' interaction network in a collaborative learning activity. Particularly, we tried to understand the structure of the interaction network during that process. Preliminary results suggest that indirect blockmodeling is highly useful for inferring and analysing the students' social roles, when the behaviour of roles are clearly different among them. This technique can be used as a monitoring service that can be embedded in collaborative learning applications.Peer ReviewedPostprint (published version

Tool wear study in edge trimming on basalt fibre reinforced plastics

[EN] In machining of reinforced fibre composite parts, abrasive fibres and material heterogeneity produce poor surface finish, delamination and tool wear. In this research, basalt fibre reinforced plastic is machined with edge trimming in order to study tool wear, using a tool holder of diameter 25 mm, with two exchangeable uncoated carbide cutting inserts. Cutting conditions (cutting speed, feed per tooth and depth) and material characteristics (fibre volume fraction and fibre orientation) are evaluated to know their influence in the flank wear (Vb) of the tool. An analysis of variance (ANOVA) was performed to study flank wear and material removal rate, and a generalized linear model (GLM) was developed. More influence variables in the flank wear are the machining conditions, being the tool life suitable for this machining and material.This work was funded by the Research Project DPI2013-44903-R-AR of the MINER.Navarro-Mas, M.; Meseguer, MD.; Sánchez Galdón, AI.; Gutiérrez, SC. (2017). Tool wear study in edge trimming on basalt fibre reinforced plastics. Procedia Manufacturing. 13:259-266. doi:10.1016/j.promfg.2017.09.067S2592661