Estimation Of Dissipation Research Articles

Non-fragile distributed mode-dependent dissipative state estimation of uncertain Markov jump systems over sensor networks

This paper considers the non-fragile distributed state estimation problem for Markov jump systems over sensor networks based on dissipative theory. Moreover, both state estimator gain variations and parameter uncertainties are assumed to be with mode-dependent for more practical modeling. On the basis of stochastic analysis and Lyapunov–Krasovskii function method, sufficient conditions with desired mode-dependent estimators are established such that the prescribed dissipative performance can be achieved. In the end, the effectiveness and applicability of the developed scheme is confirmed via the illustrative example.

About the Use of Entropy Production for the Landau\u2013Fermi\u2013Dirac Equation

In this paper, we present new estimates for the entropy dissipation of the Landau–Fermi–Dirac equation (with hard or moderately soft potentials) in terms of a weighted relative Fisher information adapted to this equation. Such estimates are used for studying the large time behaviour of the equation, as well as for providing new a priori estimates (in the soft potential case). An important feature of such estimates is that they are uniform with respect to the quantum parameter. Consequently, the same estimations are recovered for the classical limit, that is the Landau equation.

Asymptotic dynamics of a sixth-order integro-differential equation

We consider a sixth-order integro-differential equation with periodic boundary conditions. The equation describes the phase transition dynamics in ternary oil–water–surfactant systems. Using the energy methods and the basic dissipative estimate, we establish the required estimates. Furthermore, based on these estimates, we prove the existence of the attractors by a decomposition of the solution semigroup.

Non-fragile extended dissipative state estimation for delayed discrete-time neural networks: application to quadruple tank process model

This paper deals with the non-fragile state estimator design to study the robust extended dissipativity criterion for a class of discrete-time neural networks (DNNs) involving uncertainties as well as time-varying delay components. The requisite of the proposed problem is to design a proper state estimator such that the dynamics of the corresponding estimation error is extended dissipative having external disturbance and unpredictable fragility performance. By constructing an appropriate Lyapunov–Krasovskii functional (LKF), the sufficient conditions for the extended dissipativity performance of the error system obtained by means of the proposed DNNs and its estimator which includes the $$H_{\infty }$$ performance, $$L_{2}-L_{\infty }$$ performance, passivity and dissipativity performance in a unified framework. The established theoretical results are expressed in terms of linear matrix inequalities (LMIs) that can be easily checked by using the standard numerical softwares. In order to analyze the applicability and effectiveness of the proposed theoretical results, numerical examples including a quadruple tank process (QTP) system model have been illustrated with simulation results.

Experimental estimation of energy dissipation in rocking masonry walls restrained by an innovative seismic dissipator (LICORD)

This paper presents an innovative anti-seismic device for controlling the out-of-plane rocking motion of masonry walls with traditional tie-rods, called LInear COntrolled Rocking Device (LICORD). LICORD is a low-impact box connected to the extremity of the traditional tie-rod designed to mitigate rocking for medium–high intensity earthquakes. Additionally, the paper widens the knowledge about the dynamic behavior of rocking walls through the interpretation of the results of an extensive experimental campaign performed on masonry specimens composed by clay brick and cementitious mortar. Firstly, the LICORD’s single components are tested to identify their stiffness and damping properties. Secondly, free vibration tests provide actual values of coefficients of restitution on free-standing walls and walls restrained by LICORD, where the walls vary for the height to thickness ratio. For the stockier wall, the ratio of experimental/analytical coefficient of restitution varies from 88 to 98%, whereas for the slender wall, the results are less scattered, with a minimum value of 95% and a maximum value of 96%. The restrained walls are characterized by coefficients of restitution from 5 to 25% less than the values found for unrestrained walls, depending on the equivalent viscous coefficient of the shock absorbers. Moreover, LICORD demonstrated to properly absorb and damp the oscillations of the wall and control its rocking motion, strongly reducing the number of impacts and the rotation amplitudes up to 70%. Considerations about the effect of one-sided motion on the assessment of coefficient of restitution are also given. The equivalent viscous damping coefficients are observed to be on the range 4% (unrestrained wall) and 7–20% for walls restrained by LICORD.

Persistence of bioconvection‐induced mixed layers in a stratified lake

AbstractIn situ observations of biophysical interactions in natural waters typically focus on physical mechanisms influencing biological activity. Yet, biological activity can also drive physical processes in aquatic environments. A community of photoautotrophic, motile and heavy bacteria—Chromatium okenii, which requires light, sulfide, and anoxic conditions to perform anoxygenic photosynthesis, accumulates below the chemocline of the meromictic Lake Cadagno (Switzerland). Upward vertical migration drives bioconvection, which modifies the physical environment of the bacteria‐populated water to create a deep and homogeneous mixed layer of up to 1 m thickness. Continuous convection within the mixed layer and diapycnal diffusivity from its adjacent stratified surroundings determine ecologically relevant gradients. The daytime vertical migration that induce convective instabilities is well‐established. It consists in bacteria swimming upward towards light and accumulating at the upper part of the anoxic layer, leading to a locally‐unstable density excess. However, nocturnal activity has not yet been analyzed. An intensive 48‐h survey was conducted in August 2018 using standard and microstructure profilers, as well as a moored high‐resolution current meter coupled with temperature and turbidity sensors deployed across the mixed layer depth. This survey revealed a persistent mixed layer also during nighttime hours. Using a mixed layer shape model, vertical velocity observations and turbulent dissipation estimates, we conclude that photoautotrophic bacteria continue their vertical migration at night. This nocturnal activity thereby drives “dark bioconvection” and maintains the subsurface mixed bacterial layer in Lake Cadagno throughout the diel cycle.

Extended dissipative state estimation for static neural networks via delay-product-type functional

This paper studies the issue of extended dissipative state estimation for static neural networks with time-varying delays. A new delay-product-type (DPT) functional is constructed to introduce triple integrals, which can encompass some existing DPT functionals as its special cases, which leads to less conservative results. A parameter-dependent reciprocally convex inequality (PDRCI) covering some existing results is proposed to estimate the DPT functional, which can reach a tighter bound. Based on these ingredients, a novel estimator design condition is obtained to ensure the estimation error system to be asymptotically stable and extended dissipative. By using a matrix inequality decoupling technique, the estimator gain matrices can be solved by linear matrix inequalities (LMIs). Compared with some existing works, the restrictions on slack matrices are overcome, which increase the flexibility of estimator solutions. The effectiveness of the developed method is illustrated by an example.

Estimation of pulsatile energy dissipation in intersecting pipe junctions using inflow pulsatility indices

This study aims to characterize the effect of inflow pulsatility on the hydrodynamic power loss inside intersecting double-inlet, double-outlet pipe intersection (DIPI) with cross-flow mixing. An extensive set of computational fluid dynamics (CFD) simulations was performed in order to identify the individual effects of flow pulsatility parameters, i.e., amplitude, frequency, and relative phase shift between the inflow waveform oscillations, on power loss. An experimentally validated second order accurate solver is employed in this study. To predict the pulsatile flow performance of any given arbitrary inflow waveforms, we proposed three easy-to-calculate pulsatility indices. The frequency-coupled quasi-steady flow theory is incorporated to identify the functional form of pulsatile power loss as a function of these indices. Our results indicated that the power loss within the inflow branch sections, lumped outflow-junction section, and the whole conduit correlates strongly with the pulsatility of each inflow waveform, the total inflow pulsatility, and inflow frequency content, respectively. The complete CFD simulation matrix provided a unified analytical expression that predicts pulsatile power loss inside a one-degree offset DIPI geometry. The predictive accuracy of this expression is evaluated in comparison to the CFD evaluation of arbitrary multi-harmonic inflow waveforms. These results have important implications on hydrodynamic pipe networks that employ complex junctions as well as in the patient-to-patient comparison of surgically created vascular connections. Coupling the present analytical pulsatile power loss expression with non-dimensional steady power loss formulation provided a valuable predictive tool to estimate the pulsatile energy dissipation for any arbitrary junction geometry with minimum use of the costly CFD computations.

Global Existence of Smooth Solutions for a Nonconservative Bitemperature Euler Model

The bitemperature Euler model describes a crucial step of inertial confinement fusion (ICF) when the plasma is quasineutral while ionic and electronic temperatures remain distinct. The model is written as a first-order hyperbolic system in nonconservative form with partially dissipative source terms. We consider the polytropic case for both ions and electrons with different $\gamma$-law pressures. The system does not fulfill the Shizuta--Kawashima condition and, the physical entropy, which is a strictly convex function, does not provide a symmetrizer of the system. In this paper we exhibit a symmetrizer to apply the result on the local existence of smooth solutions in several space dimensions. In the one-dimensional case we establish energy and dissipation estimates leading to global existence for small perturbations of equilibrium states.

Effects of Convection and Radiation Heat Transfer on Energy Dissipation Estimation of Metal in High-cycle Fatigue

Effects of Convection and Radiation Heat Transfer on Energy Dissipation Estimation of Metal in High-cycle Fatigue

Global Bounded Weak Entropy Solutions to the Euler--Vlasov Equations in Fluid-Particle System

In this paper, we consider a fluid-particle system which describes the evolution of a two-phase flow. The system consists of the compressible Euler equations for the fluid (fluid phase) coupled with the Vlasov equation for the particles (disperse phase) through the drag force. We obtain a global bounded weak entropy solution for such one-dimensional Euler--Vlasov equations with arbitrarily large initial data for the whole range of physical adiabatic exponents $\gamma>1$. To achieve this, we apply the vanishing viscosity method and compensated compactness theory. We construct globally defined approximate solutions by adding our novel viscosity terms to the Euler equations, which together with our key observation on relative velocity plays a fundamental role in the hardest part of our proof: the uniform $L^\infty$ estimate. After deriving an entropy dissipation estimate, we prove the convergence of approximate solutions by the compensated compactness argument.

ECOSYSTEM BIOMASS AS A KEY PARAMETER DETERMINING ITS COASTAL PROTECTION SERVICE

Estimation of the flow energy dissipation induced by an ecosystem that accounts for its characteristics (i.e. biomechanical properties, morphology, density) and the incident hydrodynamic conditions is crucial if ecosystem-based coastal protection measurements want to be implemented. Characterization of a vegetated ecosystem by measuring leaf traits, biomechanical properties of plants and the number of individuals per unit area involves a lot of effort and is case-specific. Standing biomass can be a unique variable defining the flow energy attenuation capacity of the ecosystem. To explore its relation to the induced energy attenuation on the flow, a new set of experiments using real vegetation with contrasting morphology and biomechanical properties, and subjected to different incident flow conditions is presented. The obtained standing biomass-attenuation relationships will help to quantify the expected coastal protection provided by different vegetated ecosystems based on their standing biomass and the flow conditions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/-qaKkBWZApk

BATHYMETRY INVERSION IN THE SURF ZONE VIA ASSIMILATION OF REMOTELY SENSED WAVE BREAKING ENERGY DISSIPATION

In this work, a data assimilation approach treating bathymetry as an uncertain model parameter, is introduced where direct dissipation estimates from remote sensing data are the unique data source. Two dimensional wave breaking dissipation fields are retrieved on a wave-by-wave basis with the algorithms of Daz et al. (2018), who were able to reliably estimate breaking dissipation by removing spurious signals affecting electro-optical and microwave data. After a six hour application, the system was able to retrieve improved bathymetric estimates, without any in situ depth measurement. A prominent feature of this approach is its ability to reliably capture the amplitude and position of nearshore sandbars.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/Y7mgiSvmRYc

Dynamic Event-Based Non-Fragile Dissipative State Estimation for Quantized Complex Networks With Fading Measurements and Its Application

This article is concerned with the issue of dynamic event-based non-fragile dissipative state estimation for a type of stochastic complex networks (CNs) subject to a randomly varying coupling as well as fading measurements, where the variation of coupling is governed by a Markov chain. To characterize the measurement fading phenomenon for different nodes, a Rice fading model is considered with known statistics information of the coefficients. For the sake of further resource saving, a dynamic event-triggering strategy (ETS), which is proved to release less data packets than the static one, is implemented to govern the measurements transmission for each sensor to its corresponding estimator. The main objective of this article is to determine a dynamic event-based non-fragile estimator such that, for all possible parameter fluctuations in estimator gains, the estimation error system is stochastically stable with a strict ( $\Upsilon _{1}, \Upsilon _{2}, \Upsilon _{3}$ )- $\gamma $ -dissipativity. Through intensive stochastic analysis, sufficient conditions are then derived in terms LMI to guarantee the existence of the desired state estimator. Finally, the effectiveness of the proposed results are verified by two practical examples of Chua’s circuit and quadruple-tank process system (QTPS).

The nano-scale viscoelasticity using atomic force microscopy in liquid environment

We measured viscoelasticity of two nanoscale systems, single protein molecules and molecular layers of water confined between solid walls. In order to quantify the viscoelastic response of these nanoscale systems in liquid environment, the measurements are performed using two types of atomic force microscopes (AFMs), which employ different detection schemes to measure the cantilever response. We used a deflection detection scheme, available in commercial AFMs, that measures cantilever bending and a fibre-interferometer based detection which measures cantilever displacement. The hydrodynamics of the cantilever is modelled using Euler–Bernoulli equation with appropriate boundary conditions which accommodate both detection schemes. In a direct contradiction with many reports in the literature, the dissipation coefficient of a single octomer of titin I278 is found to be immeasurably low. The upper bound on the dissipation coefficient is 5 × 10−7 kg s−1, which is much lower than the reported values. The entropic stiffness of single unfolded domains of protein measured using both methods is in the range of 10 mN m−1. We show that in a conventional deflection detection measurement, the phase of the bending signal can be a primary source of artefacts in the dissipation estimates. It is recognized that the measurement of cantilever displacement, which has negligibly small phase lag due to hydrodynamics of the cantilever at low excitation frequencies, is better suited for ensuring artefact-free measurement of viscoelasticity compared to the measurement of the cantilever bending. Further, it was possible to measure dissipation in molecular layers of water confined between the tip and the substrate using fibre interferometer based AFM with similar experimental parameters. It confirms that the dissipation coefficient of a single I278 is below the detection limit of AFM. The results shed light on the discrepancy observed in the measured diffusional dynamics of protein collapse measured using Force spectroscopic techniques and single-molecule optical techniques.

Estimates of spectral wave attenuation in Antarctic sea ice, using model/data inversion

A model-data inversion is applied to an extensive observational dataset collected in the Southern Ocean north of the Ross Sea during late autumn to early winter, producing estimates of the frequency-dependent rate of dissipation by sea ice. The modeling platform is WAVEWATCH III® which accounts for non-stationarity, advection, wave generation, and other relevant processes. The resulting 9477 dissipation profiles are co-located with other variables such as ice thickness to quantify correlations which might be exploited in later studies to improve predictions. An average of dissipation profiles from cases of thinner ice near the ice edge is fitted to a simple binomial. The binomial shows remarkable qualitative similarity to prior observation-based estimates of dissipation, and the power dependence is consistent with at least three theoretical models, one of which assumes that dissipation is dominated by turbulence generated by shear at the ice-water interface. Estimated dissipation is lower closer to the ice edge, where ice is thinner, and waveheight is larger. The quantified correlation with ice thickness may be exploited to develop new parametric predictions of dissipation.

On the Effect of Block Roughness in Ogee Spillways with Flip Buckets

In this study, the effect of the presence of bed-block roughness in an ogee spillway on energy dissipation and jet length is investigated. A series of experimental and numerical tests were conducted using an ogee spillway with block roughness on the bed without a flip bucket and with a flip bucket at different take-off angles (32 °C and 52 °C). To model the free-flow surface, the volume-of-fluid (VOF) method and turbulence model from RNG k–ε were used. Results indicated that the numerical model is fairly capable of simulating a free-flow surface over an ogee spillway; using block roughness on the spillway chute without a bucket, relative energy dissipation increased by 15.4% compared to that in the spillway with a smooth bed, while for the spillway with 32 °C and 52 °C buckets, it increased by 9.5%. The jet length for a spillway with a flip bucket and roughened bed decreased by 8% to 58% compared to that in a smooth bed. Lastly, the relationships for the estimation of relative energy dissipation and jet length are presented.

The mean field Schr\xf6dinger problem: ergodic behavior, entropy estimates and functional inequalities

We study the mean field Schrödinger problem (MFSP), that is the problem of finding the most likely evolution of a cloud of interacting Brownian particles conditionally on the observation of their initial and final configuration. Its rigorous formulation is in terms of an optimization problem with marginal constraints whose objective function is the large deviation rate function associated with a system of weakly dependent Brownian particles. We undertake a fine study of the dynamics of its solutions, including quantitative energy dissipation estimates yielding the exponential convergence to equilibrium as the time between observations grows larger and larger, as well as a novel class of functional inequalities involving the mean field entropic cost (i.e. the optimal value in (MFSP)). Our strategy unveils an interesting connection between forward backward stochastic differential equations and the Riemannian calculus on the space of probability measures introduced by Otto, which is of independent interest.

On the Sobolev Stability Threshold of 3D Couette Flow in a Uniform Magnetic Field

We study the stability of the Couette flow $$(y,0,0)^T$$ in the presence of a uniform magnetic field $$\alpha (\sigma , 0, 1)$$ on $${{\mathbb {T}}}\times {{\mathbb {R}}}\times {{\mathbb {T}}}$$ using the 3D incompressible magnetohydrodynamics (MHD) equations. We consider the inviscid, ideal conductor limit $$\mathbf{Re} ^{-1}$$, $$\mathbf{R }_m^{-1} \ll 1$$ and prove that for strong and suitably oriented background fields the Couette flow is asymptotically stable to perturbations small in the Sobolev space $$H^N$$. More precisely, we show that if $$\mathbf{Re} ^{-1} = \mathbf{R }_m^{-1} \in (0,1]$$, $$\alpha > 0$$ and $$N > 0$$ are sufficiently large, $$\sigma \in {{\mathbb {R}}}{\setminus } {\mathbb {Q}}$$ satisfies a generic Diophantine condition, and the initial perturbations $$u_{\text{ in }}$$ and $$b_{\text{ in }}$$ to the Couette flow and magnetic field, respectively, satisfy $$\Vert u_{\text{ in }}\Vert _{H^N} + \Vert b_{\text{ in }}\Vert _{H^N} = \epsilon \ll \mathbf{Re} ^{-1}$$, then the resulting solution to the 3D MHD equations is global in time and the perturbations $$u(t,x+yt,y,z)$$ and $$b(t,x+yt,y,z)$$ remain $${\mathcal {O}}(\mathbf{Re} ^{-1})$$ in $$H^{N'}$$ for some $$1 \ll N'(\sigma ) < N$$. Our proof establishes enhanced dissipation estimates describing the decay of the x-dependent modes on the timescale $$t \sim \mathbf{Re} ^{1/3}$$, as well as inviscid damping of the velocity and magnetic field with a rate that agrees with the prediction of the linear stability analysis. In the Navier–Stokes case, high regularity control on the perturbation in a coordinate system adapted to the mixing of the Couette flow is known only under the stronger assumption $$\epsilon \ll \mathbf{Re} ^{-3/2}$$ (Bedrossian et al. in Ann. Math. 185(2): 541–608, 2017). The improvement in the MHD setting is possible because the magnetic field induces time oscillations that partially suppress the lift-up effect, which is the primary transient growth mechanism for the Navier–Stokes equations linearized around Couette flow.

A high-cycle fatigue energy dissipation accurate estimation method considering natural convection and radiation heat transfer

As a rapid fatigue performance estimation method, the accuracy of dissipated energy estimation by infrared thermography methodology seriously affects the prediction of fatigue parameters. An energy dissipation accurate estimation method considering natural convection and radiation is developed. Numerical simulation verifies the accuracy of the presented method, and natural convection and radiation account for a large proportion of energy dissipation estimation, which cannot be ignored. With the experimental results of FV520B stainless steel, the energy dissipations during the high-cycle fatigue process were estimated and verified. This work provides theoretical and experimental basis for accurate estimation of energy dissipation in high-cycle fatigue.