124,565 research outputs found
Verifying service continuity in a satellite reconfiguration procedure: application to a satellite
The paper discusses the use of the TURTLE UML profile to model and verify service continuity during dynamic reconfiguration of embedded software, and space-based telecommunication software in particular. TURTLE extends UML class diagrams with composition operators, and activity diagrams with temporal operators. Translating TURTLE to the formal description technique RT-LOTOS gives the profile a formal semantics and makes it possible to reuse verification techniques implemented by the RTL, the RT-LOTOS toolkit developed at LAAS-CNRS. The paper proposes a modeling and formal validation methodology based on TURTLE and RTL, and discusses its application to a payload software application in charge of an embedded packet switch. The paper demonstrates the benefits of using TURTLE to prove service continuity for dynamic reconfiguration of embedded software
Solitons in a system of three linearly coupled fiber gratings
We introduce a model of three parallel-coupled nonlinear waveguiding cores
equipped with Bragg gratings (BGs), which form an equilateral triangle. The
objective of the work is to investigate solitons and their stability in this
system. New results are also obtained for the earlier investigated dual-core
system. Families of symmetric and antisymmetric solutions are found
analytically, extending beyond the spectral gap in both the dual- and tri-core
systems. Moreover, these families persist in the case (strong coupling between
the cores) when there is no gap in the system's linear spectrum. Three
different types of asymmetric solitons are found in the tri-core system. They
exist only inside the spectral gap, but asymmetric solitons with nonvanishing
tails are found outside the gap as well. The symmetric solitons are stable up
to points at which two types of asymmetric solitons bifurcate from them. Beyond
the bifurcation, one type of the asymmetric solitons is stable, and the other
is not. Then, they swap their stability. In both the dual- and tri-core
systems, the stability region of the symmetric solitons extends far beyond the
gap, persisting in the case when the system has no gap at all. The whole
stability region of antisymmetric solitons is located outside the gap. Thus,
solitons in multi-core BGs can be observed experimentally in a much broader
frequency band than in the single-core one, and in a wider parameter range than
it could be expected.Comment: 20 text pages and 11 figure pages at the end of the document;
European Physical Journal D, in pres
Open-Ended Evolutionary Robotics: an Information Theoretic Approach
This paper is concerned with designing self-driven fitness functions for
Embedded Evolutionary Robotics. The proposed approach considers the entropy of
the sensori-motor stream generated by the robot controller. This entropy is
computed using unsupervised learning; its maximization, achieved by an on-board
evolutionary algorithm, implements a "curiosity instinct", favouring
controllers visiting many diverse sensori-motor states (sms). Further, the set
of sms discovered by an individual can be transmitted to its offspring, making
a cultural evolution mode possible. Cumulative entropy (computed from ancestors
and current individual visits to the sms) defines another self-driven fitness;
its optimization implements a "discovery instinct", as it favours controllers
visiting new or rare sensori-motor states. Empirical results on the benchmark
problems proposed by Lehman and Stanley (2008) comparatively demonstrate the
merits of the approach
Open-ended evolution to discover analogue circuits for beyond conventional applications
This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10710-012-9163-8. Copyright @ Springer 2012.Analogue circuits synthesised by means of open-ended evolutionary algorithms often have unconventional designs. However, these circuits are typically highly compact, and the general nature of the evolutionary search methodology allows such designs to be used in many applications. Previous work on the evolutionary design of analogue circuits has focused on circuits that lie well within analogue application domain. In contrast, our paper considers the evolution of analogue circuits that are usually synthesised in digital logic. We have developed four computational circuits, two voltage distributor circuits and a time interval metre circuit. The approach, despite its simplicity, succeeds over the design tasks owing to the employment of substructure reuse and incremental evolution. Our findings expand the range of applications that are considered suitable for evolutionary electronics
The role of cooperative and social enterprises: A multifaceted approach for an economic pluralism
he role of cooperative and social enterprises in contemporary market economies has been downplayed and marginalised to date by the dominant economic approaches. This insufficient attention (Kalmi, 2008 su Cambridge Journal of Economics) derives from the limited applicability of the main assumptions of microeconomic to the case of cooperative and social enterprises. We mainly refer to models. the assumption of self-seeking individuals and of profit maximisation as the only possible firm objective. The mismatch between theoretical assumptions and empirical evidence has led to the underestimation of the growth potential, weight and role of cooperative and social enterprises. We maintain that the improvement of the scientific understanding of cooperative and social enterprises requires to enlarge and deepen the assumption of the relevant theoretical models. Individuals cannot be characterised any more as purely self-interested. Instead, the importance of motivational complexity, and the diverse nature of preferences needs to be introduced in the model as suggested by the behavioural approach. Furthermore, firms cannot be interpreted any more in an exclusive way as profit maximizers. They are instead coordination mechanisms of the economic activity, as suggested by the evolutionary approach. To this end they develop specific organisational routines, and their objectives can be diverse, ranging from purely private appropriation, to mutual benefit based on reciprocity, to public benefit aim supported by other-regarding preferences. (Le teorie economiche dominanti, ed in particolare lâapproccio ortodosso e quello neo-istituzionalista, hanno sottostimato e marginalizzato il ruolo delle cooperative e delle imprese sociali nei mercati economici contemporanei. Lâinsufficiente attenzione a queste organizzazioni deriva principalmente dallâimpossibilitĂ di applicare ad esse le assunzioni principali della teoria microeconomica ortodossa, ossia la presenza di individui auto-interessati e di organizzazioni che puntino solo alla massimizzazione del profitto. Anche la teoria neo-istituzionalista non riesce a spiegare la presenza e la crescita del ruolo ricoperto da cooperative e imprese sociali. Per questa ragione, il presente paper Ăš volto a dimostrare come, per spiegare il ruolo di cooperative ed imprese sociali da un punto di vista scientifico, i principali modelli teorici economici debbano essere estesi. Innanzitutto, tanto gli individui quanto le istituzioni non possono essere piĂč assunti come soggetti meramente egoistici, ma ne vanno studiate la complessitĂ motivazionale e le strutture di preferenze, cosĂŹ come proposto dalla teoria comportamentale (behavioural economics). Inoltre, le imprese devono essere concepite come meccanismi di coordinamento delle attivitĂ economiche, come suggerito dallâapproccio evoluzionista, e devono quindi esserne analizzate le specifiche routine organizzative sviluppate al loro interno e gli obiettivi organizzativi, i quali possono variare tra gli interessi di appropriazione privata dei profitti ed obiettivi pro-sociali sostenuti da preferenze altruistiche.Cooperatives, social enterprises, organizational pluralism, economic theories
Efficient Neural Network Implementations on Parallel Embedded Platforms Applied to Real-Time Torque-Vectoring Optimization Using Predictions for Multi-Motor Electric Vehicles
The combination of machine learning and heterogeneous embedded platforms enables new potential for developing sophisticated control concepts which are applicable to the field of vehicle dynamics and ADAS. This interdisciplinary work provides enabler solutions -ultimately implementing fast predictions using neural networks (NNs) on field programmable gate arrays (FPGAs) and graphical processing units (GPUs)- while applying them to a challenging application: Torque Vectoring on a multi-electric-motor vehicle for enhanced vehicle dynamics. The foundation motivating this work is provided by discussing multiple domains of the technological context as well as the constraints related to the automotive field, which contrast with the attractiveness of exploiting the capabilities of new embedded platforms to apply advanced control algorithms for complex control problems. In this particular case we target enhanced vehicle dynamics on a multi-motor electric vehicle benefiting from the greater degrees of freedom and controllability offered by such powertrains. Considering the constraints of the application and the implications of the selected multivariable optimization challenge, we propose a NN to provide batch predictions for real-time optimization. This leads to the major contribution of this work: efficient NN implementations on two intrinsically parallel embedded platforms, a GPU and a FPGA, following an analysis of theoretical and practical implications of their different operating paradigms, in order to efficiently harness their computing potential while gaining insight into their peculiarities. The achieved results exceed the expectations and additionally provide a representative illustration of the strengths and weaknesses of each kind of platform. Consequently, having shown the applicability of the proposed solutions, this work contributes valuable enablers also for further developments following similar fundamental principles.Some of the results presented in this work are related to activities within the 3Ccar project, which has
received funding from ECSEL Joint Undertaking under grant agreement No. 662192. This Joint Undertaking
received support from the European Unionâs Horizon 2020 research and innovation programme and Germany,
Austria, Czech Republic, Romania, Belgium, United Kingdom, France, Netherlands, Latvia, Finland, Spain, Italy,
Lithuania. This work was also partly supported by the project ENABLES3, which received funding from ECSEL
Joint Undertaking under grant agreement No. 692455-2
Cyber physical systems implementation for asset management improvement: A framework for the transition
Libro en Open AccessThe transformation of the industry due to recent technologies introduction is an evolving
process whose engines are competitiveness and sustainability, understood in its broadest sense (environmental,
economic and social). This process is facing, due to the current state of scientific and technological
development, a new challenge yet even more important: the transition from discrete technological solutions
that respond to isolated problems, to a global conception where the assets, plant, processes and engineering
systems are conceived, designed and operated as an integrated complex unit. This vision is evolving
besides a set of concepts that are, in some way, to guide this development: Smart Factories, Cyber-Physical
Systems, Factory of the Future or Industry 4.0, are examples. The full integration of the operation and
maintenance (O&M) processes in the production systems is a key topic within this new paradigm. Not
only that, this evolution necessarily results in the emergence of new processes and needs of O&M, i.e.
also, the O&M will undergo a profound transformation. The transition from actual isolated production
assets to such Industry 4.0 with CPS is far from easy. This document presents a proposal to develop such
transition adapting one iteration of the Model of Maintenance Management (MMM) integrated into
ISO 55000 to the complexity of incorporating âSystem of Systemsâ CPSs maintenance. It involves several
stages: identification, prioritization, risk management, planning, scheduling, execution, control, and
improvement supported by system engineering techniques and agile/concurrent project managemen
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