scholarly journals GLMB Tracker with Partial Smoothing

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4419 ◽  
Author(s):  
Tran Nguyen ◽  
Du Kim
Keyword(s):  
Management Strategy ◽  
Threshold Value ◽  
Computational Effort ◽  
Tracking Algorithm ◽  
Multiple Objects ◽  
Short Lifespan ◽  
Wide Range ◽  
Track Management ◽  
Random Finite Sets ◽  
Track Before Detect

In this paper, we introduce a tracking algorithm based on labeled Random Finite Sets (RFS) and Rauch–Tung–Striebel (RTS) smoother via a Generalized Labeled Multi-Bernoulli (GLMB) multi-scan estimator to track multiple objects in a wide range of tracking scenarios. In the forward filtering stage, we use the GLMB filter to generate a set of labels and the association history between labels and the measurements. In the trajectory-estimating stage, we apply a track management strategy to eliminate tracks with short lifespan compared to a threshold value. Subsequently, we apply the information of trajectories captured from the forward GLMB filtering stage to carry out standard forward filtering and RTS backward smoothing on each estimated trajectory. For the experiment, we implement the tracker with standard GLMB filter, the hybrid track-before-detect (TBD) GLMB filter, and the GLMB filter with objects spawning. The results show improvements in tracking performance for all implemented trackers given negligible extra computational effort compared to standard GLMB filters.

The role of slow magnetostrophic waves in dipole formation in rapidly rotating dynamos

2021 ◽  
Author(s):  
Aditya Varma ◽  
Binod Sreenivasan
Keyword(s):  
Magnetic Field ◽  
Threshold Value ◽  
Dipole Field ◽  
Wave Frequency ◽  
Alfven Wave ◽  
Inertial Waves ◽  
Axial Dipole ◽  
Wide Range ◽  
The Magnetic Field

<p>It is known that the columnar structures in rapidly rotating convection are affected by the magnetic field in ways that enhance their helicity. This may explain the dominance of the axial dipole in rotating dynamos. Dynamo simulations starting from a small seed magnetic field have shown that the growth of the field is accompanied by the excitation of convection in the energy-containing length scales. Here, this process is studied by examining axial wave motions in the growth phase of the dynamo for a wide range of thermal forcing. In the early stages of evolution where the field is weak, fast inertial waves weakly modified by the magnetic field are abundantly present. As the field strength(measured by the ratio of the Alfven wave to the inertial wave frequency) exceeds a threshold value, slow magnetostrophic waves are spontaneously generated. The excitation of the slow waves coincides with the generation of helicity through columnar motion, and is followed by the formation of the axial dipole from a chaotic, multipolar state. In strongly driven convection, the slow wave frequency is attenuated, causing weakening of the axial dipole intensity. Kinematic dynamo simulations at the same parameters, where only fast inertial waves are present, fail to produce the axial dipole field. The dipole field in planetary dynamos may thus be supported by the helicity from slow magnetostrophic waves.</p>

Solvent-Induced Damage in Polyimide Thin Films

1989 ◽  
Vol 167 ◽  
Author(s):  
M. S. Hu
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Exposure Time ◽  
Critical Strain ◽  
Threshold Value ◽  
Weak Dependence ◽  
Polyimide Films ◽  
Band Formation ◽  
Enhanced Diffusion ◽  
Wide Range

AbstractSolvent induced damage bands formed in residually strained polyimide thin films on different substrates have been studied. Microscopy studies have shown that these bands resemble crazes. A mechanics approach Is taken to understand the band formation phenomenon.The critical strain for damage formation has been identified. This strain decreases with increase in exposure time, but always exhibits a threshold value. In contrast to the cracking of brittle films, the critical strain has only a weak dependence on the film thickness over a wide range. This behavior obtains because the crazing of the polyimide films is nucleation controlled. Strain-enhanced diffusion of solvent into the films is considered to be responsible for the property degradation that leads to damage formation.

scholarly journals Alternating direction implicit type preconditioners for the steady state inhomogeneous Vlasov equation

2017 ◽  
Vol 83 (1) ◽  
Author(s):  
Markus Gasteiger ◽  
Lukas Einkemmer ◽  
Alexander Ostermann ◽  
David Tskhakaya
Keyword(s):  
Steady State ◽  
Numerical Simulations ◽  
Vlasov Equation ◽  
Numerical Solutions ◽  
Splitting Method ◽  
Time Integration ◽  
Computational Effort ◽  
Alternating Direction Implicit ◽  
Alternating Direction ◽  
Wide Range

The purpose of the current work is to find numerical solutions of the steady state inhomogeneous Vlasov equation. This problem has a wide range of applications in the kinetic simulation of non-thermal plasmas. However, the direct application of either time stepping schemes or iterative methods (such as Krylov-based methods such as the generalized minimal residual method (GMRES) or relaxation schemes) is computationally expensive. In the former case the slowest time scale in the system forces us to perform a long time integration while in the latter case a large number of iterations is required. In this paper we propose a preconditioner based on an alternating direction implicit type splitting method. This preconditioner is then combined with both GMRES and Richardson iteration. The resulting numerical schemes scale almost ideally (i.e. the computational effort is proportional to the number of grid points). Numerical simulations conducted show that this can result in a speed-up of close to two orders of magnitude (even for intermediate grid sizes) with respect to the unpreconditioned case. In addition, we discuss the characteristics of these numerical methods and show the results for a number of numerical simulations.

Summation of Contrast in Perceived Form from Texture

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 224-224
Author(s):  
P I Laurinen ◽  
L A Olzak
Keyword(s):  
Threshold Value ◽  
Sinusoidal Grating ◽  
Vertical Orientation ◽  
Similar Frequency ◽  
The Third ◽  
Wide Range ◽  
Relative Contrast ◽  
Narrow Frequency Band ◽  
Spatial Grain ◽  
Contrast Discrimination

The relative contrast of two superimposed triangles formed by truncated sinusoidal gratings determines which appears more salient. We have previously reported that the saliency of one triangle is selectively enhanced by superimposing a third grating of similar frequency but different orientation. We now ask how the contrasts of the three gratings combine to determine saliency. Stimuli were two superimposed isosceles triangles, formed by overlaying sharply truncated patches of a sinusoidal grating, one at 1.5 cycles deg−1 tilted +45°, the other at 6 cycles deg−1, tilted −45° from vertical. The sharpest-angle apexes pointed in opposite directions (left or right). Contrasts of the gratings were initially adjusted to yield equal performance when observers chose whether the more salient target pointed left or right following a brief (400 ms) monocular exposure. In each test condition a third grating of vertical orientation (spatial frequency 1.5, 3, or 6 cycles deg−1) was added to the entire stimulus at one of six contrast levels ranging from near threshold to 10 × threshold. The point of equal saliency was re-determined from psychometric functions by varying the contrast of one triangle in a 2AFC staircase procedure. The saliency of each triangle was enhanced when the third grating was matched in frequency, but no effect occurred when the third grating differed by an octave (eg was 3 cycles deg−1). Beyond some threshold value of the third grating contrast, the contrast needed to reinstate equal salience was found to be inversely proportional to the contrast of the third grating. Our results are in agreement with the characteristics of higher-level mechanisms that mediate spatial-grain and/or pattern contrast discrimination, and suggest that form-from-texture mechanisms sum component contrasts linearly over a wide range of orientations within a narrow frequency band.

Linear Multi-Target Integrated Probabilistic Data Association Filter With Automatic Track Management for Autonomous Vehicles

2018 ◽  
Author(s):  
Andinet Hunde ◽  
Beshah Ayalew
Keyword(s):  
Target Tracking ◽  
Tracking System ◽  
Data Association ◽  
Tracking Algorithm ◽  
Probabilistic Data ◽  
Probabilistic Data Association ◽  
Address Data ◽  
Multi Target Tracking ◽  
Track Management ◽  
Track Initiation

Target tracking in public traffic calls for a tracking system with automated track initiation and termination facilities in a randomly evolving driving environment. In addition, the key problem of data association needs to be handled effectively considering the limitations in the computational resources onboard an autonomous car. In this paper, we discuss a multi-target tracking system that addresses target birth/initiation and death/termination processes with automatic track management feature. The tracking system is based on Linear Multi-target Integrated Probabilistic Data Association Filter (LMIPDAF), which is adapted to specifically include algorithms that handle track initiation and termination, clutter density estimation and track management. The performance of the proposed tracking algorithm is compared to other single and multi-target tracking schemes and is shown to have acceptable tracking error. It is further illustrated through multiple traffic simulations that the computational requirement of the tracking algorithm is less than that of optimal multi-target tracking algorithms that explicitly address data association uncertainties.

scholarly journals A New Conceptual Model for Slope-Infiltration

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 678 ◽  
Author(s):  
Renato Morbidelli ◽  
Corrado Corradini ◽  
Carla Saltalippi ◽  
Alessia Flammini ◽  
Jacopo Dari ◽  
...  
Keyword(s):  
Surface Water ◽  
Conceptual Model ◽  
Soil Type ◽  
Unsolved Problem ◽  
Threshold Value ◽  
Water Velocity ◽  
Water Infiltration ◽  
Infiltration Process ◽  
Wide Range ◽  
Steep Slopes

Rainfall infiltration modeling over surfaces with significant slopes is an unsolved problem. Even though water infiltration occurs over soil surfaces with noticeable gradients in most real situations, the typical mathematical models used were developed for infiltration over horizontal surfaces. In addition, recent investigations on infiltration over sloping surfaces have provided conflicting results, suggesting that our understanding of the process may still be lacking. In this study, our objective is to specifically examine if the surface water velocity that is negligible over near horizontal soil surfaces can affect the infiltration process over steep slopes. A new conceptual model representing a wide range of experimental results is proposed. The model represents water flow as an ensemble of infinitesimal “particles” characterized by specific velocities and assumes that only “particles” with velocity less than a threshold value can contribute to the infiltration process. The velocity distribution and the threshold value depend on slope and soil type, respectively. This conceptual model explains observed results and serves as a foundation for developing further experiments and refining models that offer more realistic representations of infiltration over sloping surfaces.

A general consideration of incident impact energy accumulation in molecular dynamics thin film simulations—a new approach using thermal control layer marching algorithms

2005 ◽  
Vol 461 (2064) ◽  
pp. 3977-3998 ◽  
Author(s):  
Hong-Chang Lin ◽  
Jee-Gong Chang ◽  
Shin-Pon Ju ◽  
Chi-Chuan Hwang
Keyword(s):  
Thin Film ◽  
Layer Thickness ◽  
Reaction Layer ◽  
Incident Energy ◽  
Thermal Control ◽  
Computational Effort ◽  
Energy Accumulation ◽  
Wide Range ◽  
The Impact ◽  
Control Layer

This paper investigates several highly accurate algorithms which can be used to calculate the morphology in a wide range of thin film process simulations, and which require minimum computational effort. Three different algorithms are considered, namely the kinetic energy corrector (KEC) algorithm, the thermal control layer marching (TLM) algorithm, and the thermal control layer marching algorithm with an incorporated KEC function (TLMC). A common characteristic of these algorithms is that they all address the recovery of the impact incident energy within the free reaction layer. However, they differ in their treatment of the thermal control layer. The TLM and TLMC algorithms consider this layer to be moveable, whereas the KEC algorithm regards it as being fixed. The advantage of employing a moveable thermal control layer is that the computational effort required to carry out simulation is reduced since the atoms lying below this layer are excluded. The relative accuracy and efficiency of the proposed algorithms are evaluated by considering their use in the simulation of the trench-filling problem associated with the damascene process. The results of the present investigation indicate that the TLM algorithm has the ability to provide an accurate morphology calculation for low and medium energy incident atoms. However, for higher incident energy impacts, the TLMC algorithm is found to be a more appropriate choice because the incorporated energy corrector function is required to remove the higher energy accumulation which occurs within the deposited atoms. Furthermore, for all three algorithms, it is noted that a suitable specification of the free reaction layer thickness is essential in determining the accuracy and efficiency of the simulation. Finally, this paper discusses the relationship between the energy absorption rate and the thickness of the free reaction layer, and presents the optimal free reaction layer thickness for different incident energy intensities.

scholarly journals Adaptive Real-Time Wavelet Denoising Architecture Based on Feedback Control Loop

2021 ◽  
Vol 9 (ICRIE) ◽  
Author(s):  
Fars Samann ◽  
◽  
Serwan Ali Bamerni ◽  
Jeeman Ahmed Khorsheed ◽  
Ahmed Khorsheed Al-sulaifanie ◽  
...  
Keyword(s):  
Feedback Control ◽  
Real Time ◽  
Window Size ◽  
Threshold Value ◽  
Wavelet Denoising ◽  
Discrete Wavelet ◽  
Control Loop ◽  
Denoising Method ◽  
Low Snr ◽  
Wide Range

The discrete wavelet transform is commonly used as a denoising step for many applications, like biomedical applications which are usually suffering from low SNR of the recorded signal. However, the choice of appropriate threshold value for DWT coefficients plays significant role in reconstructing the denoised signal. This paper presents a design of real-time wavelet denoising architecture which is suitable for wide range of real-time denoising applications. In this design, an adaptive thresholding approach based on feedback control loop is proposed to make the architecture more applicable for real-time wavelet denoising. This thresholding method considers a noise level estimator module based on first detail coefficients level 𝑑1 to calculate the unknown standard deviation of background noise. The proposed architecture is developed using MATLAB to simulate the suggested denoising method. The performance of the proposed denoising method is studied in terms of integral gain 𝐺 of feedback control and window size 𝑀 with respect to the improvement in SNR and settling time. The results imply that the proposed denoising architecture is suitable for real-time denoising applications with acceptable improvement in SNR approximately 8 dB.

scholarly journals An Efficient and Robust Multi-Object Recognition and Tracking Algorithm using Mask Region based Convolution Neural Network (R-CNN)

2019 ◽  
Vol 8 (9) ◽  
pp. 607-613
Keyword(s):  
Neural Network ◽  
Computer Vision ◽  
Object Recognition ◽  
Object Tracking ◽  
Ground Truth ◽  
Benchmark Dataset ◽  
Tracking Algorithm ◽  
Multiple Objects ◽  
High Quality ◽  
Extensive Simulation

Presently, Multi-Object tracking (MOT) is mainly applied for predicting the positions of many predefined objects across many successive frames with the provided ground truth position of the target in the first frame. The area of MOT gains more interest in the area of computer vision because of its applicability in various fields. Many works have been presented in recent years that intended to design a MOT algorithm with maximum accuracy and robustness. In this paper, we introduce an efficient as well as robust MOT algorithm using Mask R-CNN. The usage of Mask R-CNN effectively identifies the objects present in the image while concurrently creating a high-quality segmentation mask for every instance. The presented MOT algorithm is validated using three benchmark dataset and the results are extensive simulation. The presented tracking algorithm shows its efficiency to track multiple objects precisely

scholarly journals Динамика спинорной экситон-поляритонной системы в латерально сжатых GaAs микрорезонаторах при резонансном фотовозбуждении

2018 ◽  
Vol 60 (8) ◽  
pp. 1567
Author(s):  
А.А. Деменев ◽  
Н.А. Гиппиус ◽  
В.Д. Кулаковский
Keyword(s):  
Laser Pulse ◽  
Spatial Coherence ◽  
Picosecond Laser ◽  
Threshold Value ◽  
Laser Pulses ◽  
Josephson Effects ◽  
High Q ◽  
Wide Range ◽  
Linearly Polarized ◽  
Polariton Branch

AbstractThe evolution of the spatial coherence and the polarization has been studied in a freely decaying polariton condensate that is resonantly excited by linearly polarized picosecond laser pulses at the lower and upper sublevels of the lower polariton branch in a high-Q GaAs-based microcavity with a reduced lateral symmetry without excitation of the exciton reservoir. It is found that the condensate inherits the coherence of the exciting laser pulse at both sublevels in a wide range of excitation densities and retains it for several dozen picoseconds. The linear polarization of the photoexcited condensate is retained only in the condensate at the lower sublevel. The linearly polarized condensate excited at the upper sublevel loses its stability at the excitation densities higher a threshold value: it enters a regime of internal Josephson oscillations with strongly oscillating circular and diagonal linear degrees of polarization. The polariton–polariton interaction leads to the nonlinear Josephson effects at high condensate densities. All the effects are well described in terms of the spinor Gross–Pitaevskii equations. The cause of the polarization instability of the condensate is shown to be the spin anisotropy of the polariton–polariton interaction.

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