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We test whether the length of an indefinite horizon, or that the horizon is indefinite as opposed to finite, affects cooperation in repeated 3x3 Red Queen Games. With our participant population, and our experimental program and procedures, the length of the indefinite horizon significantly affects cooperation in the Prisoner's Dilemma. However, it does not significantly affect cooperation in the Red Queen Game. Nor does the indefiniteness of the horizon significantly affect cooperation in this latter game. Our results highlight the importance of learning in indefinite games with even slightly larger strategy spaces than the Prisoner's Dilemma.

Entropy regularization has been extensively adopted to improve the efficiency, the stability, and the convergence of algorithms in reinforcement learning. This paper analyzes both quantitatively and qualitatively the impact of entropy regularization for mean field games (MFGs) with learning in a finite time horizon. Our study provides a theoretical justification that entropy regularization yields time-dependent policies and, furthermore, helps stabilizing and accelerating convergence to the game equilibrium. In addition, this study leads to a policy-gradient algorithm with exploration in MFG. With this algorithm, agents are able to learn the optimal exploration scheduling, with stable and fast convergence to the game equilibrium.

This article develops a dynamic version of event-triggered model predictive control (MPC) without utilizing any terminal constraint. Such a dynamic event-triggering mechanism takes the advantages of both event- and self-triggering approaches by dealing explicitly with conservatism in the triggering rate and measurement frequency. The prediction horizon shrinks as the system states converge; we prove that the proposed strategy is able to stabilize the system even without any stability-related terminal constraint. Recursive feasibility of the optimization control problem (OCP) is also guaranteed. The simulation results illustrate the effectiveness of the scheme.

This article proposes a novel objective function formulation based on gradient descent(GD) for finite control set predictive current control(FCS-PCC) with extended horizon. FCS-PCC has become increasingly attractive for electrical drive applications owing to its short settling time, lower switching frequency, capability to handle multiple conflicting targets and feasible inclusion of constraints. However, it still suffers from high torque ripple and poor current quality at the steady state. To tackle the aforementioned issue, a GD-based objective function reformulation is employed in the FCS-PCC with extended horizon. First, the optimization problem underlying FCS-PCC is formulated as a constrained quadratic programming(QP) problem with proved convexity from a geometric perspective. Based on the above, the tracking error of the control objective is minimized more efficiently by searching along the direction of GD. Consequently, the objective function is reconstructed as the deviation between the normalized GD and derivative, combined with the extension of feasible set. The abovementioned procedures are iteratively learned in every prediction horizon. The effectiveness of the proposed algorithm is verified on a 2.2 kW induction machine(IM) platform with a prediction horizon of N=3. It is confirmed that the proposed algorithm outperforms the conventional and multistep FCS-PCC in steady state and transient state.

This work is concerned with the design of a two-step distributed state estimation scheme for large-scale systems in the presence of unknown-but-bounded disturbances and noise. The set-membership approach is employed to construct a compact set containing the states consistent with system measurements and bounded noise and disturbances. The tightened feasible region is then provided to a moving horizon estimator that determines the optimal state estimates. Partitioning of the overall problem and coordination of the resulting subproblems are achieved using decomposition of the optimality conditions and community detection. The proposed strategy is tested on a case study based on a reactor–separator system widely used in the literature. Its performance is compared to those of centralized and distributed (without set-membership) implementations, allowing to highlight its effectiveness.

International audience; This paper addresses the observability analysis and the optimal design of observation parameters in the presence of noisy measurements and parametric uncertainties. The notion of almost !-observability is introduced and a systematic procedure to assess its satisfaction for a given system with a priori known measurement noise statistics and parameter discrepancy is sketched. Moreover, the concept of observation-target quantities is introduced in order to analyze the precision with which specific chosen expressions of the state and the parameters can be reconstructed. The overall framework is exposed and validated through an illustrative example.

We label the degree to which individuals are more optimistic at long horizons relative to short horizons as the horizon bias. We examine whether time-series variation in the horizon bias can explain the time-series variation in the equity term structure. We use analyst earnings forecasts to measure the degree of the horizon bias in the stock market. Consistent with the intuition from a stylized present value model, we find that periods of above-average horizon bias are associated with negative term premiums, whereas periods of below-average horizon bias are associated with positive term premiums. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.

Near Rectilinear Halo Orbits (NRHOs) are stable or nearly stable orbits that are defined as part of the L1 and L2 halo orbit families in the circular restricted three-body problem. Within the Earth-Moon regime, the L1 and L2 NRHOs are proposed as long horizon trajectories for cislunar exploration missions, including NASA’s upcoming Gateway mission. The spacecraft, however, incurs continuous deviations due to unmodeled forces and orbit determination errors in this dynamically sensitive region. The current investigation focuses on an impulsive stationkeeping technique to maintain the spacecraft near a virtual reference orbit despite these uncertainties. The flow dynamics in the region are utilized to identify appropriate maneuver and target locations. The investigation reflects the impact of various factors on maneuver cost and efficacy. For orbits where position and velocity states are particularly sensitive to epoch time, an additional feedback control strategy is applied for phasing constraints.

Con la imagen de los horizontes históricos, se interroga de nuevo el gesto persistente en Rivera de escribir ficcionalmente sobre el pasado decimonónico, en un momento en el que la crisis del marxismo coincide con la boga de las manifestaciones de la memoria (Traverso). Desde los recuerdos familiares sobre el antisemitismo y el anticomunismo, hasta las miradas poscoloniales sobre la historia de Argentina, Gran Bretaña y Francia, se va dibujando tenuemente una tradición del “perder y resistir”, forjada con revolucionarios que han perdido las batallas contra el bando de los vencedores. En este trabajo imaginario, las referencias históricas siempre dialogan con las tradiciones literarias: estas son invocadas para escuchar los susurros de los muertos. Al lado del espectro de Marx, aparece, de modo velado, el espectro de Shakespeare, de tal modo que más allá de los determinismos realistas, la ficción asume una teatralidad que hace visible lo que retorna en el acontecer histórico. Avec l’image des horizons historiques, un geste persistant chez Rivera est rééxaminé : l’écriture de fictions autour de l’histoire du 19e siècle, dans un moment où la crise du marxisme coïncide avec la vogue des expressions mémorielles (Traverso). Depuis la mémoire familiale sur l’antisémitisme et l’anticommunisme, jusqu’aux regards postcoloniaux sur l’histoire de l’Argentine, du Royaume-Uni et de la France, une tradition du “perdre et résister” se dessine en demi-teintes, forgée avec des révolutionnaires qui ont perdu leurs batailles contre le camp des vainqueurs. Dans ce travail imaginaire, les références historiques dialoguent avec les traditions littéraires: celles-ci sont invoquées pour donner une écoute aux murmures des morts. À côté du spectre de Marx, apparaît, de façon voilée, le spectre de Shakespeare, de sorte qu’au-delà des déterminismes réalistes, la fiction assume une théâtralité qui rend visible ce qui fait retour dans le devenir de l’histoire. Through the motif of historical horizons, a persistent gesture in Rivera’s work is examined: the writing of fiction concerned with the history of the nineteenth century in a later moment defined by the coincidence of the crisis of Marxism and the increase of memory expressions (Traverso). From family memories of anti-Semitism and anticommunism through postcolonial consideration of the history of Argentina, United Kingdom and France, a “losing and resisting” tradition is quitely traced, shaped with revolutionaries who lose their fights against the vanquishers. In this imaginary work, historic references interact with literary traditions, which are invoked to let us hear the whispers of the dead. By the side of the specter of Marx, appears, thinly veiled, the specter of Shakespeare, so that beyond social and deterministic realism, fiction adopts a theatricality which renders visible the recurrences of history.

Scalar-tensor theories are a natural alternative to general relativity, as they may provide an effective dark energy phenomenology on cosmological scales while passing local tests, but their black hole solutions are still poorly understood. Here, we generalize existing no-hair theorems for spherical black holes and specific theories in the scalar-tensor class. We show that shift symmetry prevents the appearance of scalar hairs in rotating (asymptotically flat, stationary and axisymmetric) black holes for all theories in the Horndeski/beyond Horndeski/DHOST classes, but for those with a coupling between the scalar and the Gauss--Bonnet invariant. Our proof also applies to higher dimensions. We also compute the values of the scalar hair charges if shift symmetry and asymptotic flatness are violated by a time growth of the scalar field at infinity, under suitable regularity conditions at the event horizon., Comment: 14 pages, 1 figure

Since the first investment in mining operations is very high, so, it is absolutely important to model the field in three dimensions for appropriate planning and cost analysis. The whole data set belonging to the geological, geophysical and drilling exploration studies carried out in the field should be evaluated as a package. In the modelling phase, the computer-aided tri-dimensional mining software has been used instead of the classical reserve calculation methods being utilized in previous years. Thus, more realistic and shorter results are achieved. In the present work, three-dimensional seam modelling of the Adana-Tufanbeyli (Turkey) lignite field was carried out. In modelling, the coal horizon of the field was examined. Then, the sub-seam levels in the horizon were determined and after examining their geometric relationships with each other, three sub-seams were defined. Seam composites were prepared by the downhole method to make the analysis results of different sizes uniform. It is possible to make block quality estimations, which will be the basis for reserve calculations, by creating variograms in different directions. Variograms are first created in the vertical direction and then in the horizontal direction respectively, to obtain the necessary parameters. The nugget effect and structural distance parameters were obtained from the created variogram models. To assign quality estimation values on the block model, the Kriging method was used when the number of data was sufficient, and the inverse distance method was applied, when it was insufficient. As a result of this modelling study, a total of 355.617.194 tons of lignite reserves with an average calorific value of 1.153 Kcal/kg were determined in the field.

This paper presents a mathematical formulation and a heuristic approach for a new variant of the Hierarchical Chinese Postman Problem (HCPP). Indeed, we introduce the concept of periodicity, and we define and solve, for the first time, the Periodic-HCPP, denoted as P-HCPP. Given that the resulting integer programming model makes use of a big number of binary variables and given the extended time horizon considered, 30 days in our case, the problem is characterized by a high level of complexity. However, our developed heuristic is able to solve instances having up to 40 nodes, 520 arcs and 5 hierarchies, whereas a general-purpose solver like Gurobi was not able to provide solutions for instances having more than 10 nodes. While the collected results are very encouraging, we provide at the end of this paper a set of possible future extensions of this work.

This paper focuses on zero-sum stochastic differential games in the framework of forward-backward stochastic differential equations on a finite time horizon with both players adopting impulse controls. By means of BSDE methods, in particular that of the notion from Peng's stochastic \textit{% backward semigroups}, we prove a dynamic programming principle for both the upper and the lower value functions of the game. The upper and the lower value functions are then shown to be the unique viscosity solutions of the Hamilton-Jacobi-Bellman-Isaacs equations with a double-obstacle. As a consequence, the uniqueness implies that the upper and lower value functions coincide and the game admits a value., Comment: To appear in Journal of Systems Science and Complexity

On maritime images, the horizon is a linear shape separating the sea and non-sea regions. This visual cue is essential in several sea video surveillance applications, including camera calibration, digital video stabilization, target detection and tracking, and distance estimation of detected targets. Given the nature of these applications, the horizon detection algorithm must satisfy robustness and real-time constraints. Our first aim in this paper is to provide a comprehensive review of horizon detection algorithms. After analyzing assumptions and test results reported in the horizon detection literature, we found a high trade-off between robustness and real-time performance. Thus, our second aim is to propose and describe three workable techniques to reduce this trade-off. The first technique aims to increase the robustness against contrast-degraded horizons. The non-sea region right above the horizon mainly depicts the sky, coast, ship, or combination of these classes. Thus, the second technique suggests a way to handle such class variation. While we believe that the last two techniques require relatively little computations, the third technique concerns using an alternative convolutional neural network (CNN) architecture to avoid a significant quantity of redundant computations in a previous CNN-based algorithm.

In this paper, a novel model to localize a human accurately in indoor industrial environments by integrating the inertial navigation system (INS) technique with ultra wide band (UWB) technology is present. The distances between the target human and the reference node measured from INS and UWB are used by the fusion filter. To improve accuracy, the robust extended finite impulse response (EFIR) filtering algorithm is developed to operate on multi horizons (MHs), thereby providing blind suboptimal estimates. Experimental testing has shown that the real-time blind MH EFIR algorithm is almost as accurate as the EFIR filter, which requires a preliminarily determined optimal horizon.

The interactions between spin of fermionic matter and torsion in Einstein-Cartan-Sciama-Kibble (ECSK) theory of gravity provide a repulsive gravitational potential at very dense states of fermionic matter, which prevents the formation of black hole singularities inside the deeper horizon. While the fermionic matter in the black hole is attracted by the black hole at the beginning, after a critical point it is repelled to bounce at a critical high density and then expand into other side of the horizon as a newly created space, which may be considered as a non-singular, closed universe. We constructed the action of these fermions in a black hole with torsion in the framework of ECSK theory of gravity from which the free Dirac action is inferred and the interaction potential is obtained. Also, this scenario naturally solves the flatness and horizon problems of cosmology without introducing finely tuned scalar fields, or more complicated functions of the Ricci scalar R in gravitational action.

In this paper, we consider a non-standard renewal risk model with dependent claim sizes, where an insurance company is allowed to invest his/her wealth in financial assets, leading to some stochastic investment log-returns described as a general adapted cadlag process. Under the assumptions that the claim sizes are heavy-tailed and the stochastic log-return process on investments is bounded from below almost surely, we derive some asymptotic formulas for the finite-time ruin probability holding uniformly in any finite time horizon.

This article investigates $H_{\infty }$ synchronization of delayed neural networks under a receding horizon scheme, where two types of interval time-varying delays are considered according to whether the lower bound of the delay derivative is known or not. Note that a receding horizon synchronization law can be regarded as an optimization solution at each timeslot to a minimaxization problem related closely with a certain cost functional. In this article, two cost functionals with some delay-dependent matrices are introduced, respectively, for the two types of time delays. In order to obtain less conservative conditions, a novel inequality on quadratic polynomial functions is established, which includes some existing ones as its special cases. Based on the novel inequality, two sufficient conditions are derived to design the terminal weighting matrices of the cost functionals such that the resulting synchronization error system can be stabilized with a prescribed infinite horizon $H_{\infty }$ performance level. Finally, three numerical examples are used to demonstrate the validity of the proposed results.

This paper assesses the thermodynamic properties of classical Schwarzschild Black Holes. We review the thermodynamic cycle in the Geroch gedanken experiment in its relation to the classical limit of Hawking temperature, and conclude that a minimal distance requirement for pouring out radiation onto the event horizon in the gedanken experiment implies the assignment of temperature $${{T}_{{{\text{BH}}}}} \to 0$$ asympotically rather than exact absolute zero $$K$$ : a classical Schwarzschild horizon is an asymptotically zero Kelvin mechanical thermostat operated at asymptotically unit efficiency. We classify the gravitational heat pumping work done by horizon surface gravitation as perpetual motion of the third kind. The latter property does not, however, violate the Second Law, because it is impossible to extract gravitational energy from a classical Schwarzschild Black Hole in quasi-static equilibrium. The classical limit of the Bekenstein–Hawking (quantum) entropy formula is divergent as $${{S}_{{{\text{BH}}}}} \to \infty $$ , yet since $$\delta {{S}_{{{\text{BH}}}}} \to 0$$ the Nernst statement of the Third Law is not violated. Aided by the Bekenstein bound, it is shown that the Generalized Second Law persists to hold in its classical limit, when applied to the joint system of Schwarzschild Black Hole and infalling radiation gas in the Geroch gedanken experiment. The minimal horizon distance $$\delta r$$ is inferred from the Bekenstein bound, and ensures that the Geroch thermodynamic cycle be processed reversibly. The overall conclusion is that the laws of thermodynamics are not transcended by classical Schwarzschild Black Holes, despite their extremal thermodynamic properties.

In this work, we study the Tsallis holographic dark energy with Hubble horizon as IR cut-off with the energy density given by ρ Λ = 3 β 2 M p 2 H − 2 δ + 4 in f ( R , T ) theory. Considering a flat FRW Universe, we obtain the equation of state parameter guided by f ( R , T ) gravity. We investigate the correspondence between the tachyon, Dirac-Born-Infeld-essence, and the phantom scalar field models with the Tsallis holographic dark energy in the context of f ( R , T ) gravity. By equating the equation of state parameter in f ( R , T ) theory and ρ Λ with scalar field models, we reconstruct potentials and dynamics for these models for different Tsallis parameter δ . By analysis, we can show that for Tsallis holographic tachyon, Dirac-Born-Infeld-essence, and the phantom models, if the related model parameters fulfill some constraints, the accelerated expansion can be obtained in the framework of f ( R , T ) gravity.

We solve for a system that emits acceleration radiation at two different temperatures. The equilibrium states occur asymptotically in Planck distributions and transition non-thermally. The model is simple enough to obtain a global solution for the radiation spectrum analytically. We present it as a potentially useful model for investigation of non-thermal vacuum acceleration radiation in the presence of final(initial) asymptotic thermodynamic horizon(less) states in equilibrium., Accepted to Astronomy Reports. 10 pages, 4 figures

Gravitational waves (GWs) may be magnified or de-magnified due to lensing. This phenomenon will bias the distance estimation based on the matched filtering technique. Via the multi-sphere ray-tracing technique, we study the GW magnification effect and selection effect with particular attention to the stellar-mass binary black holes (BBHs). We find that, for the observed luminosity distance $\lesssim 3~\mathrm{Gpc}$, which is the aLIGO/Virgo observational horizon limit, the average magnification keeps as unity, namely unbiased estimation, with the relative distance uncertainty $\sigma(\hat{d})/\hat{d}\simeq0.5\%\sim1\%$. Beyond this observational horizon, the estimation bias can not be ignored, and with the scatters $\sigma(\hat{d})/\hat{d} = 1\%\sim 15\%$. Furthermore, we forecast these numbers for Einstein Telescope. We find that the average magnification keeps closely as unity for the observed luminosity distance $\lesssim 90~\mathrm{Gpc}$. The luminosity distance estimation error due to lensing for Einstein Telescope is about $\sigma(\hat{d})/\hat{d} \simeq 10\%$ for the luminosity distance $\gtrsim 25~\mathrm{Gpc}$. Unlike the aLIGO/Virgo case, this sizable error is not due to the selection effect. It purely comes from the unavoidably accumulated lensing magnification. Moreover, we investigated the effects of the orientation angle and the BH mass distribution models. We found that the results are strongly dependent on these two components., Comment: 9 pages, 9 figures, published in MNRAS

In the advanced driver assistance system (ADAS) and autonomous driving systems, accurate information on preceding vehicle motion states is vital for the path planning and control. To develop those intelligent driving systems, a modular integrated estimation algorithm for the preceding vehicle longitudinal and lateral states is proposed in this paper, the coupled nonlinear characteristics of vehicle dynamics are applied to improve state estimation accuracy. First, considering driver aggressiveness, a linear moving horizon estimator for the vehicle longitudinal speed is designed based on the car following model. Then, the estimated vehicle longitudinal speed is delivered to the lateral estimator module in real-time. For the arbitrary driving routes, the Serret-Frenet equations and nonlinear lateral dynamics are combined to describe the lateral motion of preceding vehicle. Furthermore, a nonlinear moving horizon estimator is constructed to estimate vehicle lateral states accurately. To reduce the computational burden, the multiple shooting (MS) method is introduced, then the objective function is divided into several segments to improve the strong nonlinearity produced by multiple iterations. The proposed estimation algorithm can effectively handle the initial biases, the additive biases and model error, which are common in the acquired signals, and provide an accurate estimate of preceding vehicle states.

This work investigates the formation of primordial black holes within a radiation fluid with an anisotropic pressure. We focus our attention on the initial conditions describing cosmological perturbations in the super horizon regime, using a covariant form of the equation of state in terms of pressure and energy density gradients. The effect of the anisotropy is to modify the initial shape of the cosmological perturbations with respect to the isotropic case. Using the dependence of the threshold $\delta_\mathrm{c}$ for primordial black holes with respect to the shape of cosmological perturbations, we estimate here how the threshold is varying with respect to the amplitude of the anisotropy. If this variation is large enough it could lead to a significant variation of the abundance of PBHs., Comment: Published in Physical Review D, Version 4: 16 pages, 7 figures, minor changes in Sec. III

The Horyu-VI nano-satellite is an international lunar mission with the purpose of studying the lunar horizon glow (LHG)—a still unclear phenomenon caused by electrostatically charged lunar dust particles. This study analyzes the mission trajectory with the hypothesis that it is launched as a secondary payload of the NASA ARTEMIS-II mission. In particular, the effect of the solar gravity gradient is studied; in fact, depending on the starting relative position of the Moon, the Earth, and the Sun, the solar gradient acts differently on the trajectory—changing it significantly. Therefore, the transfer and lunar capture problem is solved in several cases with the initial Sun–Earth–Moon angle as the key parameter. Furthermore, the inclination with respect to the Moon at capture is constrained to be equatorial. Finally, the problem of stabilization and circularization of the lunar orbit is addressed in a specific case, providing an estimate of the total propellant cost to reach the final orbit around the Moon.

This article introduces a model to estimate the risk-neutral density of stock prices derived from option prices. To estimate a complete risk-neutral density, current estimation techniques use a single mathematical model to interpolate option prices on two dimensions: strike price and time-to-maturity. Instead, this model uses B-splines with at-the-money knots for the strike price interpolation and a mixed lognormal function that depends on the option expiration horizon for the time-to-maturity interpolation. The results of this “hybrid” methodology are significantly better than other risk-neutral density extrapolation methods when applied to the recovery theorem.

Security issues of cyber-physical systems have become a timely and hot topic in recent years. In this brief, we investigate the power-constrained optimal denial-of-service (DoS) attack strategy with multiple power levels on state estimation over infinite-time horizon. We start from the two-level case and explicitly derive out the basic form of optimal attack strategy. In order to handle the intractability brought about by the larger number of levels, we develop an equivalent property for general multi-level cases that the multi-level scheduling can be viewed as a feasible combination of several sub-schedules with a designed stochastic-triggered manner, which provides a necessary condition of optimal solution. Moreover, based on the practical communication model, we give the condition under which the optimal schedule can be uniquely and explicitly determined for the two-pick strategy. Numerical simulations are accomplished to verify the effectiveness of our proposed methods.

The study investigated changes in soil reaction among surface and near surface horizons of four soil groups as affected by wet and dry seasons in Southeastern Nigeria. A geological map of the area guided soil sampling. Free survey approach was used in locating soil profiles. Soil samples were collected based on horizon differentiation and samples were collected from the AB-horizon (near-surface) and the A-horizon (Surface). Routine laboratory analyses were conducted on these soil samples after sieving through a 2-mm sieve. Data were subjected to analysis of variance (ANOVA) using SAS Statistical Computer Package. There were significant (p

The ship motion system is a nonlinear control object, and its system parameters exhibit time-varying characteristics with the ship motion state, which increases the difficulty of control. Therefore, parameter identification has an important significance for the stability of ship motion control. Aiming at the real-time identification problem of the nonlinear and time-varying ship motion system during movement, this paper reconstructs the ship motion system with the propeller speed and rudder angle as control variables and designs an online identification algorithm with the sliding time window method based on the extended Kalman filter algorithm. In addition, to solve the problem of noise in ship motion data collected in real-time, a real-time wavelet filter is developed to perform online preprocessing of the input data of the identification algorithm. The applicability of the method is further demonstrated via a model-scale Korea Research Institute of Ships and Ocean Engineering container ship free-running experiments in a basin.

We present new ideas on tests of fundamental symmetries in polarization experiments at the NICA facility. Specifically, we explore the possibilities of high precision tests of the Standard Model by parity violation and searches of Beyond the Standard Model semistrong breaking of time reversal invariance in double polarized proton-deuteron scattering, taking advantage of high intensity beams of polarized protons and deuterons available at NICA. In both cases, we propose to use the new technique of polarized beam with precessing horizontal polarizations, and polarized deuterons are the favored choice. An external target in the extracted beam is optional for the parity violation experiment, which requires furnishing Nuclotron and/or new Booster with very modest new instrumentation. One should not overlook this potential for substantial broadening of the spin physics horizon at the NICA facility.

We consider the Sharma–Mittal holographic dark energy (SMHDE) model within the framework of a spatially homogeneous and isotropic flat Friedmann-Robertson-Walker (FRW) Universe by taking various values of the model parameters $$R$$ and $$\delta$$ , and the Hubble horizon is taken as the infrared cutoff. The deceleration parameter $$(q)$$ changes its sign from positive to negative. Hence, the SMHDE model explains the recent phase transition of the cosmos from decelerated to accelerated phase. To discriminate geometrically the SMHDE model from the Lambda — cold dark matter ( $$\Lambda$$ CDM), we calculate and plot the statefinder diagnostic pairs $$(r,s)$$ and $$(r,q)$$ . The evolutionary trajectory of the statefinder pair $$(r,s)$$ specifies the Chaplygin gas behaviour of the SMHDE model. The evolutionary trajectories of the statefinder pair $$(q,r)$$ of the SMHDE model approach together with the de Sitter expansion ( $$q=-1$$ , $$r=1$$ ) in the future, while it evolves above the matter-dominated Universe, i.e., the standard cold dark matter (SCDM) model ( $$r=1$$ , $$q=0.5$$ ) at early times. Additionally, we also examine the stability of the SMHDE model through squared sound speed.

Today’s 3-D seismic surveys usually contain hundreds of inline and crossline vertical seismic slices. Seismic interpreters usually need to spend weeks or even months for manually picking horizons on vertical seismic slices. Researchers have developed algorithms to accelerate horizon picking and most algorithms employ the seismic reflector’s dip as the input. However, the computed seismic reflector’s dip is usually inaccurate near and across the discontinuities in the seismic images. Note that the time samples which belong to the same horizon should have approximate similar seismic instantaneous phase values. We propose to automatically track the seismic horizon simultaneously considering the seismic reflector’s dip and instantaneous phase attributes. Our algorithm aims to achieve three objectives: 1) minimizing the difference between the dip computed using tracked horizon and seismic dip attribute, 2) minimizing the difference among instantaneous phase value of the time samples on the tracked horizon, and 3) the tracked horizon exactly passes through user-defined control points (seeds). A constrained conjugate least-square algorithm is employed to solve our optimization problem. The applications show that the tracked horizon which only uses dip attribute would “jump” from one seismic event to another seismic event near the unconformity zone. However, the horizon tracked using the proposed method strictly follows the same seismic event over the whole seismic survey.

We consider the anisotropy-based filtering problem for a linear discrete time-varying multiplicative noise system on a finite time horizon. A random disturbance with an inaccurately known distribution is fed to the system input. The uncertainty in the description of this distribution is characterized by a constraint on the anisotropic functional. The output of the original system is estimated using the selected filter of a certain type according to the principle of minimizing the performance indicator in the form of the anisotropic norm of the filtering error system. Based on the lemma on the boundedness of the anisotropic norm of the filtering error system, relations for the unknown filter matrices are derived. As special cases, we consider anisotropy-based filtering problems for a system with measurement dropouts as well as a similar problem for a system with a filter of a special type. A numerical example where the method is used to synthesize an anisotropy-based filter is given.

Finite Control Set Model Predictive Control (FCS-MPC) is an alternative to conventional linear controllers in power converters due to its attractive properties such as its conceptual simplicity, flexibility, direct consideration of non linearities as well as constraints, and fast control response. This last feature imposes computational constraints and short prediction horizons are therefore needed. In fact, in many applications an horizon one FCS-MPC controller is used. However, using FCS-MPC with a short prediction horizon in topologies that exhibit non-minimum phase behavior such as active-front-end rectifiers, dc-dc boost converters, and Z-source converters, among others, may lead to control issues. This work studies the origin of these control issues using nonlinear control theory considering a dc-dc boost converter as a case study. It is shown that the difficulty to directly control the converter output voltage using short horizon FCS-MPC is the resulting unstable internal dynamic, as the short horizon FCS-MPC controller acts like an input-output linearizing controller. To solve the problem of the unstable internal dynamic, a short horizon FCS-MPC controller based on input-state linearization is proposed allowing correct operation of the system. Experimental results show the feasibility of the proposal.

We show that any static linear perturbations around Schwarzschild black holes enjoy a set of conserved charges which forms a centrally extended Schr\"{o}dinger algebra sh(1) = sl$(2,\mathbb{R}) \ltimes \mathcal{H}$. The central charge is given by the black hole mass, echoing results on black hole entropy from near-horizon diffeomorphism symmetry. The finite symmetry transformations generated by these conserved charges correspond to Galilean and conformal transformations of the static field and of the coordinates. This new structure allows one to discuss the static response of a Schwarzschild black hole in the test field approximation from a symmetry-based approach. First we show that the (horizontal) symmetry protecting the vanishing of the Love numbers recently exhibited by Hui et al, dubbed the HJPSS symmetry, coincides with one of the sl$(2,\mathbb{R})$ generators of the Schr\"{o}dinger group. Then, it is demonstrated that the HJPSS symmetry is selected thanks to the spontaneous breaking of the full Schr\"{o}dinger symmetry at the horizon down to a simple abelian sub-group. The latter can be understood as the symmetry protecting the regularity of the test field at the horizon. In the 4-dimensional case, this provides a symmetry protection for the vanishing of the Schwarzschild Love numbers. Our results trivially extend to the Kerr case., Comment: 22+5 pages, clarifications added on the symmetry criterion, extension to Kerr added in Appendix, version published in JHEP

Peridynamic governing equations of fluid mechanics for barotropic flow are developed. As a special case of such a flow, linearized acoustics is also considered. The peridynamic governing equation of acoustics is also developed and discussed in detail. In order to obtain these new peridynamic governing equations, integral operators called “peridynamic D operators” are developed systematically, which are obtained by directly requiring the peridynamic D operators to converge to corresponding classical differential operators as the generalized material horizon approaches 0. Even though peridynamic D operators are applied only to fluid mechanics, acoustics, and heat conduction in an anisotropic inhomogeneous material in the present paper, it is clear that these peridynamic D operators can be used in any other field of mathematical physics to obtain a peridynamic (nonlocal) version of the governing equations. As an application of the newly obtained peridynamic governing equations, a time-dependent 3D (three-dimensional) peridynamic acoustics equation with a sound source is analytically solved for two different initial pressure disturbance profiles, and the results are discussed. These are believed to be the first exact analytical solutions for peridynamic acoustics.

The spatial and time behaviors of fluid flows at different Reynolds numbers and free-stream turbulence intensity levels are studied by combining dynamic mode decomposition (DMD) and moving horizon estimation to detect flow-regime transitions. In more detail, the norm of residuals provided by DMD when processing successive snapshots of the flow velocity field shows a trend that is identified by means of a moving horizon estimator based on a switching model. This allows detecting the change from stable to unstable flow regimes, which in turn enables to extract modes, frequencies, and growth rates of com- plex structures such as vortices, characterizing the fluid flow in the spatial and temporal domains. Different cases of experimental measurements given by a particle image velocimetry are analyzed to recognize the complexity of the underlying flow physics, while showing the effectiveness of the proposed approach.

In peridynamic models for fracture, the dissipated fracture energy is regularized over a non-local region denoted as the peridynamic horizon. This paper investigates the influence of this parameter on the dynamic fracture process in brittle solids, using two as well as three dimensional simulations of dynamic fracture propagation in a notched plate for two loading cases. The predicted crack speed for the various scenarios of the initially stored energy, also known as the velocity toughening behavior as well as characteristics of the crack surface topology obtained in different crack propagation regimes in 3D computational simulations are compared with the experimentally observed crack velocity and fracture surfaces for Polymethyl Methacrylate (PMMA) specimens. In addition, we investigate the influence of the specimen size on the dynamic fracture process using two dimensional peridynamic simulations. The fracture strengths and the velocity toughening relationship obtained from different specimen sizes are compared with the Linear Elastic Fracture Mechanics (LEFM) size effect relationship and with results from experiments, respectively.

The standard cosmological model is inherently relativistic, and yet a wide range of cosmological observations can be predicted accurately from essentially Newtonian theory. This is not the case on `ultra-large' distance scales, around the cosmic horizon size, however, where relativistic effects can no longer be neglected. In this paper, we present a novel suite of 53 fully relativistic simulations generated using the gevolution code, each covering the full sky out to $z \approx$ 0.85, and approximately 1930 square degrees out to $z \approx$ 3.55. These include a relativistic treatment of massive neutrinos, as well as the gravitational potential that can be used to exactly calculate observables on the past light cone. The simulations are divided into two sets, the first being a set of 39 simulations of the same fiducial cosmology (based on the Euclid Flagship 2 cosmology) with different realisations of the initial conditions, and the second which fixes the initial conditions, but varies each of seven cosmological parameters in turn. Taken together, these simulations allow us to perform statistical studies and calculate derivatives of any relativistic observable with respect to cosmological parameters. As an example application, we compute the cross-correlation between the Doppler magnification term in the convergence, $\kappa_v$, and the CDM+baryon density contrast, $\delta_{\rm cb}$, which arises only in a (special) relativistic treatment. We are able to accurately recover this term as predicted by relativistic perturbation theory, and study its sample variance and derivatives with respect to cosmological parameters., Comment: 9 pages, 6 figures, corresponds to published version

Optimal wave energy control is noncausal as the control command is optimized based on incoming wave force. Therefore, implementation of wave energy control requires forecasting of future wave force. A real-time latching control algorithm based on short-term wave force prediction is developed in this study to tackle such noncausality. The future wave forces are forecasted using a gray model. The receding horizon strategy is used to optimize the control command online, over the prediction horizon interval. Based on the predicted wave forces, the power extraction is maximized by locking and releasing the buoy alternately according to the optimized control command. Simulation results show that the power extraction is increased substantially with implementation of the developed real-time latching control algorithm, even if the future wave forces are predicted. Effects of prediction length and prediction error on the energy conversion are examined. It is found that more wave energy is harvested when a long prediction length is employed while prediction error decreases the control efficiency. The extreme load of power takeoff system increases when the wave energy control is implemented although its travel distance is hardly varied.

We develop a mathematical model of the coronavirus propagation in different countries (Brazil, India, US, Japan, Israel, Spain, Sweden), in the city of Moscow, and across the world. The pandemic spreads by a highly complex dynamics because it occurs in open nonhomogeneous systems where new infection foci erupt from time to time, triggering new transmission chains from infected to susceptible people. In general, statistical data collected as cumulative and epidemic curves are a superposition of many distinct local pandemic waves. In our modeling, we use the system of Feigenbaum’s discrete logistic equations (a logistic map) that describes the variation of the total number of infected over time. We show that this is the optimal model for the description of pandemic propagation in open nonhomogeneous systems with large errors in statistical data. We develop a procedure for isolating local waves, determining their model parameters, and predicting further evolution of each wave. We show that this model provides a good description of the statistical data and makes realistic forecasts. The forecast horizon depends on the degree of system closure and homogeneity. We calculate the start and end times of each wave, the peak, and the total number of infected in the current wave.

This brief proposes an adaptation of the Generalized Predictive Control (GPC) for ramp-reference tracking. The second-order difference operation and the plant model are used to get an augmented model with two embedded integrators and whose output is the tracking error. Differently from other GPC-based tracking algorithms, the proposed approach does not require information about the reference parameters, and the GPC prediction horizon is composed of the predicted errors instead of the expected plant outputs. Thus, the optimization function and the receding horizon strategy used in conventional GPC can be applied to get the control law. Simulation and experimental results prove that the proposed approach can successfully track constant and ramp references. The proposed method is applicable for single-input single-outputs plants. However, the mathematical background presented in this brief can be used in the development of new GPC strategies.

Culture as a dynamic system of meaningful relations can naturally accommodate a hermeneutic analysis. In this essay, the notion of Gadamer’s hermeneutics as involving interpretable meaning throughout experiential reality permits a natural concordance with an understanding of culture as meaningful. The Gadamerian idea that prejudices inform the horizons that make our experiences intelligible is applied to the view that culture is both a self-enclosed structure that is given by one’s horizon and one that continuously points past this horizon in genuine dialogue. Nevertheless, in seeing culture as a coherent system that transcends itself, we are consequently faced with a dilemma regarding the evolution of one’s cultural horizons: whether past horizons can survive the creation of novel ones through dialogue. However, this may be resolved through Gadamer’s understanding of the functions of sameness and difference within horizonal evolution, and how these functions feature in the distinction between a shared ontological ground and the horizons through which the ground is interpreted. Ultimately, we showcase how it is noncontradictory to suppose that culture is both self- and other-referential.

The trade-off between optimality and complexity has been one of the most important challenges in the field of robust Model Predictive Control (MPC). To address the challenge, we propose a flexible robust MPC scheme by synergizing the multi-stage and tube-based MPC approaches. The key idea is to exploit the non-conservatism of the multi-stage MPC and the simplicity of the tube-based MPC. The proposed scheme provides two options for the user to determine the trade-off depending on the application: the choice of the robust horizon and the classification of the uncertainties. Beyond the robust horizon, the branching of the scenario-tree employed in multi-stage MPC is avoided with the help of tubes. The growth of the problem size with respect to the number of uncertainties is reduced by handling \emph{small} uncertainties via an invariant tube that can be computed offline. This results in linear growth of the problem size beyond the robust horizon and no growth of the problem size concerning small magnitude uncertainties. The proposed approach helps to achieve a desired trade-off between optimality and complexity compared to existing robust MPC approaches. We show that the proposed approach is robustly asymptotically stable. Its advantages are demonstrated for a CSTR example.

The widely used Novikov-Thorne relativistic thin disc equations are only valid down to the radius of the innermost stable circular orbit (ISCO). This leads to an undetermined boundary condition at the ISCO, known as the inner stress of the disc, which sets the luminosity of the disc at the ISCO and introduces considerable ambiguity in accurately determining the mass, spin and accretion rate of black holes from observed spectra. We resolve this ambiguity by self-consistently extending the relativistic disc solution through the ISCO to the black hole horizon by calculating the inspiral of an average disc particle subject to turbulent disc forces, using a new particle-in-disc technique. Traditionally it has been assumed that the stress at the ISCO is zero, with material plunging approximately radially into the black hole at close to the speed of light. We demonstrate that in fact the inspiral is less severe, with several (~4-17) orbits completed before the horizon. This leads to a small non-zero stress and luminosity at and inside the ISCO, with a local surface temperature at the ISCO between ~0.15 and 0.3 times the maximum surface temperature of the disc, in the case where no dynamically important net magnetic field is present. For a range of disc parameters we calculate the value of the inner stress/surface temperature, which is required when fitting relativistic thin disc models to observations. We resolve a problem in relativistic slim disc models in which turbulent heating becomes inaccurate and falls to zero inside the plunging region., 27 pages, 8 figures, accepted for publication in MNRAS

We study a quadratic hedging problem for a sequence of contingent claims with random weights in discrete time. We obtain the optimal hedging strategy explicitly in a recursive representation, without imposing the non-degeneracy (ND) condition on the model and square integrability on hedging strategies. We relate the general results to hedging under random horizon and fair pricing in the quadratic sense. We illustrate the significance of our results in an example in which the ND condition fails., 20 pages

Matrix---not only the arrays of numbers but also has been used as a tool for many calculations in various subjects. Its inverse, eigen values, eigen vectors are of great importance to know its characters. In this paper I have discussed about some new properties of Hermitian, Skew Hermitian matrices, diagonalisation, eigen values, eigen vectors, spectrum, which will open up a new horizon to the students of Mathematics. Also, in this paper I have authored two totally new theorems for students and researchers . SB’s Theorem 1 is on Normality of a block diagonal matrix and SB’s Theorem 2 is on Spectrum of eigen values. These ideas came to me in course of teaching. Hope, these two theorems will be of great help for the students of Physics and Chemistry as well.

In this paper, a fast-moving horizon state estimation algorithm for nonlinear continuous systems with measurement noises and model disturbances is developed. The optimization problem required to be solved at each sampling instant is formulated into a backward nonlinear optimal control problem over the finite past. Once prior knowledge of the observed system is available, constraints can be further imposed. The highly efficient and accurate symplectic pseudospectral algorithm is taken as the core solver, which leads to the symplectic pseudospectral moving horizon estimation (SP-MHE) method. The developed SP-MHE is first evaluated by numerical simulations for a hovercraft. Then the developed method is extended to parameter estimation and applied to a chaotic system with an unknown parameter. Simulation results show that the SP-MHE can generate accurate estimations even under large sampling periods or large noise where regular filters fail. In addition, the SP-MHE exhibits excellent online efficiency, suggesting it can be used for scenarios where the sampling period is relatively small.

In this paper, we consider the creation/annihilation of a wormhole in the matter and dark energy universe based on wormhole cosmology. Several cases for the generation of a wormhole are reviewed, and the events are found to happen by controlling the input phantom (ghost) fields. However, when we adopt the wormhole cosmological model, a throat is created, expands, and disappears at late time with the hubble horizon in a matter-phantom-based universe background.