Decidability of the Initial-State Opacity of Real-Time Automata

2018 ◽  
pp. 44-60
Author(s):  
Lingtai Wang ◽  
Naijun Zhan
Keyword(s):  
Real Time ◽  
Initial State

scholarly journals Handling Initial Conditions in Vector Fitting for Real Time Modeling of Power System Dynamics

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2471
Author(s):  
Tommaso Bradde ◽  
Samuel Chevalier ◽  
Marco De Stefano ◽  
Stefano Grivet-Talocia ◽  
Luca Daniel
Keyword(s):  
Dynamical Systems ◽  
Power System ◽  
System Dynamics ◽  
Real Time ◽  
Initial Conditions ◽  
Test System ◽  
Initial State ◽  
Power System Dynamics ◽  
Vector Fitting ◽  
Time Modeling

This paper develops a predictive modeling algorithm, denoted as Real-Time Vector Fitting (RTVF), which is capable of approximating the real-time linearized dynamics of multi-input multi-output (MIMO) dynamical systems via rational transfer function matrices. Based on a generalization of the well-known Time-Domain Vector Fitting (TDVF) algorithm, RTVF is suitable for online modeling of dynamical systems which experience both initial-state decay contributions in the measured output signals and concurrently active input signals. These adaptations were specifically contrived to meet the needs currently present in the electrical power systems community, where real-time modeling of low frequency power system dynamics is becoming an increasingly coveted tool by power system operators. After introducing and validating the RTVF scheme on synthetic test cases, this paper presents a series of numerical tests on high-order closed-loop generator systems in the IEEE 39-bus test system.

Dynamically Feasible Periodic Trajectories for Generic Spatial Three-Degree-of-Freedom Cable-Suspended Parallel Robots1

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Giovanni Mottola ◽  
Clément Gosselin ◽  
Marco Carricato
Keyword(s):  
Real Time ◽  
General Type ◽  
Three Dimensional ◽  
Initial State ◽  
End Effector ◽  
Periodic Trajectories ◽  
Real Time Applications ◽  
State Of Rest ◽  
Three Degree Of Freedom ◽  
Inertia Forces

Cable-suspended robots may move beyond their static workspace by keeping all cables under tension, thanks to end-effector inertia forces. This may be used to extend the robot capabilities, by choosing suitable dynamical trajectories. In this paper, we consider three-dimensional (3D) elliptical trajectories of a point-mass end effector suspended by three cables from a base of generic geometry. Elliptical trajectories are the most general type of spatial sinusoidal motions. We find a range of admissible frequencies for which said trajectories are feasible; we also show that there is a special frequency, which allows the robot to have arbitrarily large oscillations. The feasibility of these trajectories is verified via algebraic conditions that can be quickly verified, thus being compatible with real-time applications. By generalizing previous studies, we also study the possibility to change the frequency of oscillation: this allows the velocity at which a given ellipse is tracked to be varied, thus providing more latitude in the trajectory definition. We finally study transition trajectories to move the robot from an initial state of rest (within the static workspace) to the elliptical trajectory (and vice versa) or to connect two identical ellipses having different centers.

scholarly journals Real-time broadening of nonequilibrium density profiles and the role of the specific initial-state realization

2017 ◽  
Vol 95 (3) ◽  
Author(s):  
R. Steinigeweg ◽  
F. Jin ◽  
D. Schmidtke ◽  
H. De Raedt ◽  
K. Michielsen ◽  
...  
Keyword(s):  
Real Time ◽  
Initial State ◽  
Density Profiles

On the initial-state assimilation for limited-area air-quality forecasts

2020 ◽  
Author(s):  
Rostislav Kouznetsov ◽  
Mikhail Sofiev
Keyword(s):  
Air Quality ◽  
Real Time ◽  
Air Pollutant ◽  
Optimal Interpolation ◽  
Limited Area ◽  
Time Data ◽  
Initial State ◽  
Skill Scores ◽  
Forecast Lead Time ◽  
Set Up

<p>An ensemble of 9 regional Air Quality models is being run operationally within CAMS-50 project providing the 3D fields of air-pollutant distribution over Europe. The models are initialized from their previous-day's forecasts for 00Z and run for 4 days forward. The same models are used for near-real-time reanalysis of the previous day involving the air-quality observations to adjust the modelled  fields via data assimilation methods, such as 3D-var or optimal-interpolation procedures.  In this set-up the observed near-real-time data do not affect the forecasts.  Development of a method to improve the forecast quality by using the assimilated fields from the previous-day analysis is one of the goals for the CAMS-61 project.</p><p>As a prototype evaluation for this study, we made several tests with SILAM model (http://silam.fmi.fi) initializing the simulations from the assimilated or non-assimilated states and evaluated the evolution of the model skill scores along the forecast lead time. The tests were made for summer and winter seasons and for initialization time of 00Z vs 12Z.  In order to generalize the results, and make them independent on particular implementation of 3D-VAR in SILAM, the tests were made also with initialization from the analyses made with other CAMS-50 models.  That experiment utilized the list of species and vertical available in the CAMS-50 product catalog. </p><p>The results of the simulation corroborated with our earlier studies that showed a quite quick relaxation of the scores for runs initialized from analyses to the free-run state: with certain variability between the species, the runs converged to the free-run trajectory generally within several hours.  We also investigated the issues connected with initialization from the incomplete set of species and sparse vertical, which might make the scores of the forecast initialized from the incomplete assimilated model state being worse than the ones from the free-run model.</p><p> </p>

scholarly journals Sensory feedback independent pre-song vocalizations correlate with current state of motor preparation

2019 ◽  
Author(s):  
Divya Rao ◽  
Satoshi Kojima ◽  
Raghav Rajan
Keyword(s):  
Real Time ◽  
Sensory Feedback ◽  
Motor Preparation ◽  
Initial State ◽  
Final State ◽  
Current State ◽  
Tennis Serve ◽  
Simple Movement ◽  
Summary Statement ◽  
The Brain

ABSTRACTMany self-initiated, learned, motor sequences begin by repeating a simple movement, like ball-bouncing before a tennis serve, and this repetition is thought to represent motor preparation. Do these simple movements provide real-time sensory feedback used by the brain for getting ready or do they simply reflect internal neural preparatory processes? Here, we addressed this question by examining the introductory notes (INs) that zebra finches repeat before starting their learned song sequence. INs progress from a variable initial state to a stereotyped final state before each song and are thought to represent motor preparation before song. Here, we found that the mean number of INs before song and the progression of INs to song were not affected by removal of two sensory feedback pathways (auditory and proprioceptive). In both feedback-intact and feedback-deprived birds, the presence of calls (other non-song vocalizations), just before the first IN, was correlated with fewer INs before song and an initial state closer to song. Finally, the initial IN state correlated with the time to song initiation. Overall, these results show that INs do not provide real-time sensory feedback for preparing the motor system. Rather, repetition of INs, and possibly, other such simple movements, may reflect the “current” state of internal neural preparatory processes involved in getting the brain ready to initiate a learned movement sequence.SUMMARY STATEMENTThe number and progression of introductory notes to song in the zebra finch are not affected by removal of sensory feedback.

scholarly journals Near real-time adjusted reanalysis forcing data for hydrology

2017 ◽  
Author(s):  
Peter Berg ◽  
Chantal Donnelly ◽  
David Gustafsson
Keyword(s):  
Real Time ◽  
Arctic Region ◽  
Analysis Data ◽  
Global Scale ◽  
Current Data ◽  
The Arctic ◽  
Data Sets ◽  
Initial State ◽  
Time Step ◽  
Data Set

Abstract. Updating climatological forcing data to near current data are compelling for impact modelling, e.g. to update model simulations or to simulate recent extreme events. Hydrological simulations are generally sensitive to bias in the meteorological forcing data, especially relative to the data used for the calibration of the model. The lack of daily resolution data at a global scale has previously been solved by adjusting re-analysis data global gridded observations. However, existing data sets of this type have been produced for a fixed past time period, determined by the main global observational data sets. Long delays between updates of these data sets leaves a data gap between present and the end of the data set. Further, hydrological forecasts require initialisations of the current state of the snow, soil, lake (and sometimes river) storage. This is normally conceived by forcing the model with observed meteorological conditions for an extended spin-up period, typically at a daily time step, to calculate the initial state. Here, we present a method named GFD (Global Forcing Data) to combine different data sets in order to produce near real-time updated hydrological forcing data that are compatible with the products covering the climatological period. GFD resembles the already established WFDEI method (Weedon et al., 2014) closely, but uses updated climatological observations, and for the near real-time it uses interim products that apply similar methods. This allows GFD to produce updated forcing data including the previous calendar month around the 10th of each month. We present the GFD method and different produced data sets, which are evaluated against the WFDEI data set, as well as with hydrological simulations with the HYPE model over Europe and the Arctic region. We show that GFD performs similarly to WFDEI and that the updated period significantly reduces the bias of the reanalysis data, although less well for the last two months of the updating cycle. For real-time updates until the current day, extending GFD with operational meteorological forecasts, a large drift is present in the hydrological simulations due to the bias of the meteorological forecasting model.

scholarly journals Impact of the Initial State on BDS Real-Time Orbit Determination Filter Convergence

2018 ◽  
Vol 10 (2) ◽  
pp. 111 ◽  
Author(s):  
Yun Qing ◽  
Yidong Lou ◽  
Yang Liu ◽  
Xiaolei Dai ◽  
Yi Cai
Keyword(s):  
Real Time ◽  
Orbit Determination ◽  
Initial State ◽  
Filter Convergence

An Analog Method for Real-Time Forecasting of Summer Monsoon Subseasonal Variability

2007 ◽  
Vol 135 (12) ◽  
pp. 4149-4160 ◽  
Author(s):  
Prince K. Xavier ◽  
B. N. Goswami
Keyword(s):  
Real Time ◽  
Summer Monsoon ◽  
Large Scale ◽  
Initial Conditions ◽  
Empirical Orthogonal Functions ◽  
Initial Condition ◽  
Analog Method ◽  
Initial State ◽  
Orthogonal Functions ◽  
Modeling Data

Abstract A physically based empirical real-time forecasting strategy to predict the subseasonal variations of the Indian summer monsoon up to four–five pentads (20–25 days) in advance has been developed. The method is based on the event-to-event similarity in the properties of monsoon intraseasonal oscillations (ISOs). This two-tier analog method is applied to NOAA outgoing longwave radiation (OLR) pentad averaged data that have sufficiently long records of observation and are available in nearly real time. High-frequency modes in the data are eliminated by reconstructing the data using the first 10 empirical orthogonal functions (EOFs), which together explain about 75% of the total variance. In the first level of the method, the spatial analogs of initial condition pattern are identified from the modeling data. The principal components (PCs) of these spatial analogs, whose evolution history of the latest five pentads matches that of the initial condition pattern, are considered the temporal PC analogs. Predictions are generated for each PC as the average evolution of PC analogs for the given lead time. Predicted OLR values are constructed using the EOFs and predicted PCs. OLR data for 1979–99 are used as the modeling data and independent hindcasts are generated for the period 2000–05. The skill of anomaly predictions is rather high over the central and northern Indian region for lead times of four–five pentads. The phases and amplitude of intraseasonal convective spells are predicted well, especially the long midseason break of 2002 that resulted in large-scale drought conditions. Skillful predictions can be made up to five pentads when started from an active initial state, whereas the limit of useful predictions is about two–three pentads when started from break initial conditions. An important feature of this method is that unlike some other empirical methods to forecast monsoon ISOs, it uses minimal time filtering to avoid any possible endpoint effects and hence may be readily used for real-time applications. Moreover, as the modeling data grow with time as a result of the increased number of observations, the number of analogs would also increase and eventually the quality of forecasts would improve.

scholarly journals Quarkonia dynamics in the QGP with open quantum systems

2022 ◽  
Vol 258 ◽  
pp. 05009
Author(s):  
Stéphane Delorme ◽  
Thierry Gousset ◽  
Roland Katz ◽  
Pol-Bernard Gossiaux
Keyword(s):  
Real Time ◽  
Quark Gluon Plasma ◽  
Open Quantum Systems ◽  
Gluon Plasma ◽  
Quantum Systems ◽  
Master Equations ◽  
Temperature Evolution ◽  
One Dimension ◽  
Initial State ◽  
Time Dynamics

We investigate the real-time dynamics of a correlated heavy quarkantiquark pair inside the Quark-Gluon Plasma using new quantum master equations derived from first QCD principles and based on the work of Blaizot & Escobedo [4]. The full equations are directly numerically solved in one-dimension to reduce computing costs and is used to gain insight on the dynamics in both a static and evolving medium following a Björken-like temperature evolution. The effect of the initial state on the dynamics is also studied.

scholarly journals Real-Time Deformation Measurements Using Single Image Photogrammetry

2021 ◽  
Vol 1203 (2) ◽  
pp. 022027
Author(s):  
Andrej Hideghéty
Keyword(s):  
Real Time ◽  
Image Plane ◽  
Major Axis ◽  
White Background ◽  
Load Testing ◽  
Initial State ◽  
Semi Major Axis ◽  
Time Deformation ◽  
Matlab Code ◽  
Target Template

Abstract Most photogrammetric measurements are currently based on image acquisition in the field and subsequent processing in office environment with certain temporal delay. However, in some cases it is necessary to process the data real-time, or at least in-situ. Bridge load testing is an example of measurement processing directly at the place of imaging, where almost immediate information about the current state or change of the object is required. An algorithm is developed for these purposes, including a camera controlling software and a MATLAB code that identifies and quantifies the shifts of the observed points in the image plane. The observed points are in the shape of black disks on a white background. Using a horizontal camera position individual epochs are captured. Each image is immediately transferred to a computer via Wi-Fi. The MATLAB code then loads the image and binarizes it. Binarization of the image is performed by the Canny edge detector. Using normalized 2-D cross-correlation, the algorithm determines the approximate coordinates based on a target template. A function performs least squares ellipse fitting and determines the center of the target in sub-pixel accuracy, the semi-major axis, the semi-minor axis and the rotation angle of the ellipse. The target detection is executed in a while cycle loop, which compares the point coordinates from each epoch to the initial state, thus quantifying the deformations in pixels. If the next image is not yet available, the loop restarts. The deformations are calculated based on the known scale of each target. This paper presents a detailed description of the development of the algorithm, the results achieved and the proposed improvements going forward.

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