2,802 research outputs found
Quasi-potentials of the entropy functionals for scalar conservation laws
We investigate the quasi-potential problem for the entropy cost functionals
of non-entropic solutions to scalar conservation laws with smooth fluxes. We
prove that the quasi-potentials coincide with the integral of a suitable
Einstein entropy.Comment: 26 pages, 4 figure
Convergence of the one-dimensional Cahn-Hilliard equation
We consider the Cahn-Hilliard equation in one space dimension with scaling a
small parameter \epsilon and a non-convex potential W. In the limit \espilon
\to 0, under the assumption that the initial data are energetically
well-prepared, we show the convergence to a Stefan problem. The proof is based
on variational methods and exploits the gradient flow structure of the
Cahn-Hilliard equation.Comment: 23 page
Towards Testing and Analysis of Systems that Use Serialization
AbstractObject serialization facilitates the flattening of structured objects into byte streams and is therefore important for all component-based applications that strongly rely on data-exchange among components. Unfortunately, implementing and controlling the serialization mechanisms may expose the software to subtle faults. This paper paves the way towards testing and analysis techniques specifically tailored to the assessment of software that uses serialization. In particular, we introduce a taxonomy of abstractions and terms to semantically characterize and classify the main data-exchange cases, which serialization can be involved with. The resulting conceptual framework provides a means to forecast how erroneous implementations of serialization would look like in different cases, thus enabling the focusing of testing and analysis techniques to address serialization-related faults
Optimal sensor placement through Bayesian experimental design: effect of measurement error and number of sensors
Sensors networks for the health monitoring of structural systems ought to be designed to
render both accurate estimations of the relevant mechanical parameters and an affordable
experimental setup. Therefore, the number, type and location of the sensors have to be chosen so
that the uncertainties related to the estimated health are minimized. Several deterministic methods
based on the sensitivity of measures with respect to the parameters to be tuned are widely used.
Despite their low computational cost, these methods do not take into account the uncertainties
related to the measurement process. In former studies, a method based on the maximization of the
information associated with the available measurements has been proposed and the use of
approximate solutions has been extensively discussed. Here we propose a robust numerical
procedure to solve the optimization problem: in order to reduce the computational cost of the
overall procedure, Polynomial Chaos Expansion and a stochastic optimization method are
employed. The method is applied to a flexible plate. First of all, we investigate how the information
changes with the number of sensors; then we analyze the effect of choosing different types of sensors
(with their relevant accuracy) on the information provided by the structural health monitoring
system
Cost-Benefit Optimization of Sensor Networks for SHM Applications
Structural health monitoring (SHM) is aimed to obtain information about the structural integrity of a system, e.g., via the estimation of its mechanical properties through observations collected with a network of sensors. In the present work, we provide a method to optimally design sensor networks in terms of spatial configuration, number and accuracy of sensors. The utility of the sensor network is quantified through the expected Shannon information gain of the measurements with respect to the parameters to be estimated. At assigned number of sensors to be deployed over the structure, the optimal sensor placement problem is ruled by the objective function computed and maximized by combining surrogate models and stochastic optimization algorithms. For a general case, two formulations are introduced and compared: (i) the maximization of the information obtained through the measurements, given the appropriate constraints (i.e., identifiability, technological and budgetary ones); (ii) the maximization of the utility efficiency, defined as the ratio between the information provided by the sensor network and its cost. The method is applied to a large-scale structural problem, and the outcomes of the two different approaches are discussed
Self-Test Components for Highly Reconfigurable Systems
Abstract Verification of component-based systems presents new challenges not yet completely addressed by existing testing techniques. This paper proposes a new approach for automatically testing highly reconfigurable component-based systems, i.e., systems that can be obtained by changing some components. The paper presents an industrial case that motivates our research and proposes a testing infrastructure that tracks run-time information for components. The collected information is used for automatic testing new versions of existing components and new configurations of existing systems
ReSpecTX: Programming Interaction Made Easy
In this paper we present the ReSpecTX language, toolchain, and standard library as a first step of a path aimed at closing the gap between coordination languages \u2013 mostly a prerogative of the academic realm until now \u2013 and their industrial counterparts. Since the limited adoption of coordination languages within the industrial realm is also due to the lack of suitable toolchains and libraries of reusable mechanisms, ReSpecTX equips a core coordination language (ReSpecT) with tools and features commonly found in mainstream programming languages. In particular, ReSpecTX makes it possible to provide a reference library of reusable and composable interaction patterns
Novel Opportunities for Tuple-based Coordination: XPath, the Blockchain, and Stream Processing
The increasing maturity of some well-established technologies \u2013 such as XPath \u2013 along with the sharp rise of brand-new ones \u2013 i.e. the blockchain \u2013 presents new opportunities to researchers in the field of multi-agent coordination. In this position paper we briefly discuss a few technologies which, once suitably interpreted and integrated, have the potential to impact the very roots of tuple-based coordination as it stems from the archetypal LINDA model
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