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There are three properties which define the global effect on power of a resynthesis step: change in function, change in spurious dynamic activity, and change in delay. In this paper, it is shown that the prediction of change in po...
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There are three properties which define the global effect on power of a resynthesis step: change in function, change in spurious dynamic activity, and change in delay. In this paper, it is shown that the prediction of change in power due to change in functionality and change in spurious dynamic activity is accurate at high levels of estimator abstraction. Change in power due to change in delay is not. However, the magnitude of the effect of delay on power during resynthesis is shown to be the least critical of the three properties.
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Research in the field of intertemporal choice has been growing in recent decades and its contribution is increasingly recognized in various disciplines such as Economics, Psychology, Neuroscience, Medicine, and Political Sciences....
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Research in the field of intertemporal choice has been growing in recent decades and its contribution is increasingly recognized in various disciplines such as Economics, Psychology, Neuroscience, Medicine, and Political Sciences. This extensive research has mainly focused on the analysis of the anomalies of the DU model, both from an empirical point of view, through the conduct of experiments, and from a theoretical point of view, through the proposal of psychological explanations and alternative models. Given the developments observed in the study of intertemporal choice, it is necessary to identify the contributions which have been provided so far. Therefore, the aim of this paper is to offer a systematic review of the existing literature on anomalies in inter-temporal choice which allows researchers from different disciplines to understand the main works in the last 30 years and to be aware of the main gaps and current trends in research. Moreover, some future lines of research are proposed.
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This note is concerned with bandwidth allocation-based switched dynamic triggering control under DoS attacks and time delay. To prevent DoS attacks from causing open-loop unstable operation of the system with single-channel transm...
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This note is concerned with bandwidth allocation-based switched dynamic triggering control under DoS attacks and time delay. To prevent DoS attacks from causing open-loop unstable operation of the system with single-channel transmission, we present a primary-redundancy (PR) communication structure on the basis of limited bandwidth allocation; the correlation of communication delay bound between PR channels is introduced. To save the limited bandwidth, we propose a dynamic the event-triggered mechanism (DETM). Then, a switched delay system model is established to describe system dynamic driven by primary channel control, redundancy channel control, and unstable operation under DoS attacks. Further, by using the convex combination method, a switching law for PR channel is designed with the aim of keeping the concealment of the redundancy channel. With the switching law, a criterion of exponential stability is obtained by using piecewise Lyapunov–Krasovskii functional method. A co-design method is proposed to obtain feedback control gains, DETM parameters and switching law parameters. Finally, two simulation examples are illustrated to verify the validness of our proposed method.
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We describe the development and validation of an operational space weather tool to forecast propagation delay times between L1 and Earth using the Weimer and King (2008) tilted phase front technique. A simple flat plane convection...
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We describe the development and validation of an operational space weather tool to forecast propagation delay times between L1 and Earth using the Weimer and King (2008) tilted phase front technique. A simple flat plane convection delay method is currently used by the NOAA Space Weather Prediction Center (SWPC) to propagate the solar wind from a monitoring satellite located at L1 to a point upstream of the magnetosphere. This technique assumes that all observed solar wind discontinuities, such as interplanetary shocks and interplanetary coronal mass ejection boundaries, are in a flat plane perpendicular to the Sun-Earth line traveling in the GSE X direction at the observed solar wind velocity. In reality, these phase plane fronts can have significantly tilted orientations, and by relying on a ballistic propagation method, delay time errors of ±15 min are common. In principle, the propagation time delay product presented here should more accurately predict L1 to Earth transit times by taking these tilted phase plane fronts into account. This algorithm, which is based on the work of Weimer and King (2008), is currently running in real time in test mode at SWPC as part of the SWPC test bed. We discuss the current algorithm performance, and via our detailed validation study, show that there is no significant difference between the two propagation methods when run in a real-time operational environment.
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This article studies the time delay resolution of radar, which refers to the ability to distinguish the delay of multiple adjacent targets. We propose a novel coarse-fine joint super-resolution time delay estimation (TDE) strategy...
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This article studies the time delay resolution of radar, which refers to the ability to distinguish the delay of multiple adjacent targets. We propose a novel coarse-fine joint super-resolution time delay estimation (TDE) strategy for passive radar using orthogonal frequency division multiplexing (OFDM) signals. First, the modulation symbol domain (MSD) method is employed to estimate the coarse delay and Doppler parameters of the targets. The delay dimension is then oversampled by reference signal compensation (RSC) methods. To achieve super-resolution and high accuracy of the target delay, we present a method based on a 1-D fully convolutional network (1-D FCN). This method takes 1-D segments of coarse time delay parameters in the oversampling delay dimension as inputs, which reduces computational complexity. The simulation and experimental results show that the proposed method outputs low sidelobes, which greatly reduces the influence of strong targets on the delay estimation of adjacent weak targets. Besides, it can also easily realize fractional delay estimation.
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In this paper, we investigate the stability of stochastic delay differential systems with delayed impulses by Razumikhin methods. Some criteria on the pth moment exponential stability are obtained. It is shown that if a stochastic...
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In this paper, we investigate the stability of stochastic delay differential systems with delayed impulses by Razumikhin methods. Some criteria on the pth moment exponential stability are obtained. It is shown that if a stochastic delay differential system is exponentially stable, then under some conditions, its stability is robust or weaken with respect to delayed impulses. Moreover, it is also shown that an unstable stochastic delay system can be successfully stabilized by delayed impulses. The effectiveness of the proposed results is illustrated by three examples.
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This paper develops a finite-time control approach for nonlinear teleoperation systems, which is capable of unifying the study of model uncertainties, actuator saturation, and asymmetric time-varying delays in the same framework. ...
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This paper develops a finite-time control approach for nonlinear teleoperation systems, which is capable of unifying the study of model uncertainties, actuator saturation, and asymmetric time-varying delays in the same framework. First, a novel anti-windup compensator is designed to analyze the effect of actuator saturation. To achieve the finite-time tracking, a nonsmooth generalized switched filter is also investigated. By introducing the anti-windup compensator and the generalized switched filter into the adaptive fuzzy control torque design, a novel finite-time controller is developed. By using the multiple Lypaunov-Krasovskii functionals method, the resulting closed-loop system is state-independent input-to-output practical stable (SIIOpS) and based on this, it is proved to be finite-time SIIOpS. It is shown that the asymptotic convergence of the adaptive estimation errors and the finite-time convergence of the position tracking errors are obtained, whether the robots contact with the human operator/environment or not. Finally, the effectiveness is demonstrated by the simulation results.
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Uncertainty of effective delayed neutron fraction βeff is evaluated in terms of three quantities; uncertainties of the basic delayed neutron constants, energy dependence of delayed neutron yield V~m-d in the low energy side below...
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Uncertainty of effective delayed neutron fraction βeff is evaluated in terms of three quantities; uncertainties of the basic delayed neutron constants, energy dependence of delayed neutron yield V~m-d in the low energy side below about 50 keV and in the high energy side above about 4 MeV, and the uncertainties of the fission cross sections of fuel elements. The uncertainty of βeff due to the delayed neutron yield is expressed by a linearized formula assuming that the delayed neutron yield does not depend on the incident energy, and the energy dependence is supplemented by using the detailed energy dependence proposed by D'Angelo and Filip.
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In this paper, two novel adaptive finite-time control schemes are proposed for position tracking of nonlinear teleoperation system, which dynamic uncertainties, actuator saturation, and time-varying communication delays are consid...
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In this paper, two novel adaptive finite-time control schemes are proposed for position tracking of nonlinear teleoperation system, which dynamic uncertainties, actuator saturation, and time-varying communication delays are considered. First, a novel auxiliary variable is designed to provide more stable performance. The radial basis function (RBF) neural network is introduced to estimate dynamic uncertainties. Second, two adaptive finite-time control schemes are investigated. In control scheme I, the RBF neural network and the gain switching strategy are applied to compensate the actuator saturation. In control scheme II, an auxiliary compensation filter and the compensation adaptive update laws, which contain the finite-time structure, are developed for dealing with saturation. Third, the finite-time adaptive controller is designed in each of these two control schemes. Based on the multiple Lyapunov function method, the closed-loop teleoperation system with these two control methods is proved to be bounded and finite-time stability. Finally, the simulation experiments are performed and the comparisons with other control methods are shown. The effectiveness of the proposed control schemes is demonstrated.
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This paper presents a new control strategy for a spherical motion platform capable of three DOFs translational and three DOFs unlimited rotational motion undergoing time delay problems. The control is based on a state prediction a...
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This paper presents a new control strategy for a spherical motion platform capable of three DOFs translational and three DOFs unlimited rotational motion undergoing time delay problems. The control is based on a state prediction and preview method to make a state correctly track a time-varying desired trajectory despite input time delay and disturbance. The spherical motion platform can suffer from a delay effect since it needs a wireless data link to control a cockpit sphere without any mechanical linkage. The delay decreases operation efficiency and further causes control instability. The proposed prediction-based preview control (PPC) offers that a state vector under input time delay is predicted using a disturbance predictor attenuating the disturbance effect. In addition, a predictor-based previewed reference with the state prediction is applied to the controller to achieve desired tracking control. In numerical simulations, it is shown that the proposed controller stabilizes the state to the desired trajectory under delay and disturbance, whereas most existing controllers only show delayed tracking. Finally, the proposed controller is applied to the motion platform, and the result shows excellent performance minimizing the effect of time delay and disturbance.
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