Finite-Time Stability for Caputo–Katugampola Fractional-Order Time-Delayed Neural Networks

Neural Processing Letters - In this paper, an original scheme is presented, in order to study the finite-time stability of the equilibrium point, and to prove its existence and uniqueness, for...     

Real-time scene background initialization based on spatio-temporal neighborhood exploration

In this paper, we address the problem of scene background initialization to define a background model free from foreground objects. The complexity of this task resides in the continuous clutter of the scene by moving and stationary objects. To face this challenge, we propose a robust real-time iterative model completion method based on online block-level processing to initialize the background with low computational cost. First, temporal data analysis is conducted to cluster similar blocks. Meanwhile, a two-folded inter-block spatial neighborhood exploration is performed. It aims to capture relationships among neighboring clusters and reduce the number of candidate clusters employed in the next phase. Then, a smoothness analysis between neighboring locations is performed to iteratively reconstruct the background based on a newly proposed edge matching metric and an inter-block color discontinuity. Extensive evaluations of the proposed approach on the public Scene Background Initialization 2015 dataset and on the Scene Background Modeling Contest 2016 dataset revealed a performance superior or comparable to state-of-the-art methods.

     

Visco‐hyperelastic constitutive model for modeling the quasi‐static behavior of polyurethane foam in large deformation

Flexible polyurethane foam is widely used in numerous applications such as seats and mattresses, due to its low stiffness and its ability to absorb deformation energy. The main objective of this article is to model the quasi‐static mechanical behavior of three types of polyurethane foam in large deformation and to compare these three foams with three proposed models. The uniaxial compression/decompression tests at three different strain rates were performed. The test results show that the three foams present different plateau stresses, maximum stresses, and abilities to absorb energy. Moreover, polyurethane foam also presents a nonlinear hyperelastic behavior and a viscoelastic behavior in large deformation. Three visco‐hyperelastic models which include a hyperelastic component and a memory component are proposed to model these behaviors. Model parameters were identified using the experimental data and a proper identification method. These models were validated on these three types of foam with the aim to present comparison results. The comparison results show that Ogden's viscoelastic model best agrees with the experimental results. POLYM. ENG. SCI., 55:1795–1804, 2015. © 2014 Society of Plastics Engineers     

State estimation for nonlinear conformable fractional‐order systems: A healthy operating case and a faulty operating case

The issue of estimating states for classical integer‐order nonlinear systems has been widely addressed in the literature. Yet, generalization of existing results to the fractional‐order framework represents a fertile area of research. Note that, recently, a new and advantageous type of fractional derivative, the conformable derivative, was defined. So far, the general query of designing observers for conformable fractional‐order systems has not been investigated. In addition, it has been proved in the literature that some important tools for stability analysis of fractional‐order systems are valid using the conformable derivative concept, but invalid using other fractional derivative concepts. Motivated by the cited facts, this paper presents a first‐state estimation scheme for fractional‐order systems under the conformable derivative concept. A healthy operating case and a faulty operating case are treated. In this paper, a version of Barbalat's lemma, which is invalid using the well‐known Caputo derivative, is exploited to prove the convergence of the estimation errors. In order to validate the theoretical results, a numerical example is studied in the simulation section.     

Adaptive estimation of component faults and actuator faults for nonlinear one‐sided Lipschitz systems

Fault estimation for classical nonlinear Lipschitz systems has been subject to several research works. So far, much less interest has been given to the more generalized class of systems, namely, one‐sided Lipchitz systems. Dealing with component faults and actuator faults, only very few works have been done to reconstruct these types of faults for this new class of systems. A major limitation of the previous works is that the fault vector to be estimated there does not give any information about the actual faulty physical parameters of the system, so component faults and actuator faults are not distinguishable. In this paper, a set of possible faulty parameters in the system is estimated. Component faults and actuator faults are separated and distinguished. The effectiveness of the proposed method is shown through simulations for a numerical example.     

Assisted DASH-aware networking over SDN–CCN architecture

Photonic Network Communications - High bandwidth demand is incited by online video streaming that has become a fundamental of many consumers’ lives. To provide the best user experience taking...     

On Observer Design for Nonlinear Caputo Fractional‐Order Systems

The observer design problem for integer‐order systems has been the subject of several studies. However, much less interest has been given to the more general fractional‐order systems, where the fractional‐order derivative is between 0 and 1. In this paper, a particular form of observers for integer‐order Lipschitz, one‐sided Lipschitz and quasi‐one‐sided Lipschitz systems, is extended to the fractional‐order calculus. Then, the obtained states estimates are used for an eventual feedback control, and the separation principle is tackled. The effectiveness of the proposed scheme is shown through simulation for two numerical examples.     

Study of clay's mineralogy effect on mechanical properties of ceramic body using an experimental design

Three clays minerals namely illite (I), montmorillonite (M), and kaolin (K) were chosen as references to study the effect of mixture composition of clays on the mechanical properties and the shrinkage of the fired ceramic. The study was accomplished using the experimental design methodology. More specifically, a mixture design was carried out in order to establish relationships between mechanical strength and shrinkage of finished products and the proportions of the three clay mineral references in the mixture. The statistical study shows that the fitted models were adequate to describe these properties of fired ceramic bodies. The results demonstrate that the mechanical resistance was mainly governed by the amount of montmorillonite mineral. In fact, the mixture design performed in this study shows clearly that montmorillonite can be incorporated in industrial ceramic products up to 45 wt% with high mechanical resistance. On the other hand, the shrinkage decreases strongly with the amount of kaolin in the mixture and increases with the amount of illite while montmorillonite exhibits moderate effect on this property. The higher strength was shown in mixture in which mullite and anorthite appear together due to the presence of kaolinite and illite and give, as a consequence, a synergic power.