This document describes a method for correcting smear in images captured by frame transfer CCD cameras when there are significant changes in illumination between frames. Existing smear correction algorithms assume constant illumination, which is not always valid. The proposed method models smear using a matrix equation that accounts for variable illumination levels transitioning between frames. It was developed for fast polarimetric imaging but could benefit other applications involving highly variable scenes synchronized with detector readout.
Investigation of repeated blasts at Aitik mine using waveform cross correlationIvan Kitov
We present results of signal detection from repeated events at the Aitik and Kiruna mines in Sweden as based on waveform cross correlation. Several advanced methods based on tensor Singular Value Decomposition is applied to waveforms measured at seismic array ARCES, which consists of three-component sensors.
The document describes two algorithms for enhancing cometary coma morphology in digital images: the radial weighted model and median coma model. The radial weighted model multiplies each pixel value by its distance from the comet's nucleus, removing the typical 1/r intensity gradient. The median coma model calculates the median pixel value on concentric circles from the nucleus to build a synthetic coma model, which can then be subtracted from or divided into the original image. Examples show how these techniques enhance structural details in cometary comae compared to unprocessed images. The source code for implementing these algorithms is freely available online.
This document summarizes a study that used sigmoidal parameterization and Metropolis-Hasting (MH) inversion to estimate seismic velocity models from traveltime data. The key points are:
1) Sigmoidal functions were used to parameterize discontinuous velocity fields, allowing for sharp variations while maintaining continuity.
2) Ray tracing and the MH algorithm were used to invert traveltime data and estimate model parameters.
3) Tests on synthetic models showed the MH method produced higher resolution velocity models that better fit the observed traveltime data, compared to other global optimization methods like very fast simulated annealing.
International Refereed Journal of Engineering and Science (IRJES) is a peer reviewed online journal for professionals and researchers in the field of computer science. The main aim is to resolve emerging and outstanding problems revealed by recent social and technological change. IJRES provides the platform for the researchers to present and evaluate their work from both theoretical and technical aspects and to share their views.
www.irjes.com
Four experiments were conducted using a paint can hanging from a spring. In the first experiment, the paint can oscillated purely vertically, and PCA isolated this behavior in a single principal component, capturing 95% of the variance. When noise was added by shaking the cameras in the second experiment, PCA was still able to isolate the oscillatory behavior but with less accuracy. In experiments three and four where the paint can moved in both vertical and horizontal directions, PCA extracted the multidimensional behavior with the expected rank and reasonable accuracy.
Interferogram Filtering Using Gaussians Scale Mixtures in Steerable Wavelet D...CSCJournals
An interferogram filtering is presented in this paper. The main concern of the proposed scheme is to lower the residues count mean while preserving the location and jump height of the lines of phase discontinuity. The proposed method is based on a statistical model of the coefficients of multi-scale oriented basis. Neighborhoods of coefficients at adjacent positions and scales are modeled as the product of two independent random variables: a Gaussian vector and a hidden positive scalar multiplier. Under this model, the Bayesian least squares estimate of each coefficient reduces to a weighted average of the local linear estimates over all possible values of the hidden multiplier variable. The performance of this method substantially has the advantages of reducing number of residuals without affecting line of height discontinuity.
P-Wave Onset Point Detection for Seismic Signal Using Bhattacharyya DistanceCSCJournals
In seismology Primary p-wave arrival identification is a fundamental problem for the geologist worldwide. Several numbers of algorithms that deal with p-wave onset detection and identification have already been proposed. Accurate p- wave picking is required for earthquake early warning system and determination of epicenter location etc. In this paper we have proposed a novel algorithm for p-wave detection using Bhattacharyya distance for seismic signals. In our study we have taken 50 numbers of real seismic signals (generated by earthquake) recorded by K-NET (Kyoshin network), Japan. Our results show maximum standard deviation of 1.76 sample from true picks which gives better accuracy with respect to ratio test method.
This poster was created in LaTeX on a Dell Inspiron laptop with a Linux Fedora Core 4 operating system. The background image and the animation snapshots are dxf meshes of elastic waveform solutions, rendered on a Windows machine using 3D Studio Max.
Investigation of repeated blasts at Aitik mine using waveform cross correlationIvan Kitov
We present results of signal detection from repeated events at the Aitik and Kiruna mines in Sweden as based on waveform cross correlation. Several advanced methods based on tensor Singular Value Decomposition is applied to waveforms measured at seismic array ARCES, which consists of three-component sensors.
The document describes two algorithms for enhancing cometary coma morphology in digital images: the radial weighted model and median coma model. The radial weighted model multiplies each pixel value by its distance from the comet's nucleus, removing the typical 1/r intensity gradient. The median coma model calculates the median pixel value on concentric circles from the nucleus to build a synthetic coma model, which can then be subtracted from or divided into the original image. Examples show how these techniques enhance structural details in cometary comae compared to unprocessed images. The source code for implementing these algorithms is freely available online.
This document summarizes a study that used sigmoidal parameterization and Metropolis-Hasting (MH) inversion to estimate seismic velocity models from traveltime data. The key points are:
1) Sigmoidal functions were used to parameterize discontinuous velocity fields, allowing for sharp variations while maintaining continuity.
2) Ray tracing and the MH algorithm were used to invert traveltime data and estimate model parameters.
3) Tests on synthetic models showed the MH method produced higher resolution velocity models that better fit the observed traveltime data, compared to other global optimization methods like very fast simulated annealing.
International Refereed Journal of Engineering and Science (IRJES) is a peer reviewed online journal for professionals and researchers in the field of computer science. The main aim is to resolve emerging and outstanding problems revealed by recent social and technological change. IJRES provides the platform for the researchers to present and evaluate their work from both theoretical and technical aspects and to share their views.
www.irjes.com
Four experiments were conducted using a paint can hanging from a spring. In the first experiment, the paint can oscillated purely vertically, and PCA isolated this behavior in a single principal component, capturing 95% of the variance. When noise was added by shaking the cameras in the second experiment, PCA was still able to isolate the oscillatory behavior but with less accuracy. In experiments three and four where the paint can moved in both vertical and horizontal directions, PCA extracted the multidimensional behavior with the expected rank and reasonable accuracy.
Interferogram Filtering Using Gaussians Scale Mixtures in Steerable Wavelet D...CSCJournals
An interferogram filtering is presented in this paper. The main concern of the proposed scheme is to lower the residues count mean while preserving the location and jump height of the lines of phase discontinuity. The proposed method is based on a statistical model of the coefficients of multi-scale oriented basis. Neighborhoods of coefficients at adjacent positions and scales are modeled as the product of two independent random variables: a Gaussian vector and a hidden positive scalar multiplier. Under this model, the Bayesian least squares estimate of each coefficient reduces to a weighted average of the local linear estimates over all possible values of the hidden multiplier variable. The performance of this method substantially has the advantages of reducing number of residuals without affecting line of height discontinuity.
P-Wave Onset Point Detection for Seismic Signal Using Bhattacharyya DistanceCSCJournals
In seismology Primary p-wave arrival identification is a fundamental problem for the geologist worldwide. Several numbers of algorithms that deal with p-wave onset detection and identification have already been proposed. Accurate p- wave picking is required for earthquake early warning system and determination of epicenter location etc. In this paper we have proposed a novel algorithm for p-wave detection using Bhattacharyya distance for seismic signals. In our study we have taken 50 numbers of real seismic signals (generated by earthquake) recorded by K-NET (Kyoshin network), Japan. Our results show maximum standard deviation of 1.76 sample from true picks which gives better accuracy with respect to ratio test method.
This poster was created in LaTeX on a Dell Inspiron laptop with a Linux Fedora Core 4 operating system. The background image and the animation snapshots are dxf meshes of elastic waveform solutions, rendered on a Windows machine using 3D Studio Max.
COMPLEMENTARY VISION BASED DATA FUSION FOR ROBUST POSITIONING AND DIRECTED FL...ijaia
The present paper describes an improved 4 DOF (x/y/z/yaw) vision based positioning solution for fully 6
DOF autonomous UAVs, optimised in terms of computation and development costs as well as robustness
and performance. The positioning system combines Fourier transform-based image registration (Fourier
Tracking) and differential optical flow computation to overcome the drawbacks of a single approach. The
first method is capable of recognizing movement in four degree of freedom under variable lighting conditions, but suffers from low sample rate and high computational costs. Differential optical flow computation, on the other hand, enables a very high sample rate to gain control robustness. This method, however, is limited to translational movement only and performs poor in bad lighting conditions. A reliable positioning system for autonomous flights with free heading is obtained by fusing both techniques. Although the vision system can measure the variable altitude during flight, infrared and ultrasonic sensors are used for robustness. This work is part of the AQopterI8 project, which aims to develop an autonomous
flying quadrocopter for indoor application and makes autonomous directed flight possible.
The document discusses using a hidden Markov model to analyze temporal changes in forest cover from satellite imagery over time. It outlines how the HMM can model land cover classes and transitions between classes over multiple time steps. The HMM finds the most likely sequence of land cover classes for each pixel location using algorithms like Viterbi or forward-backward. This allows analyzing a time series of images while handling issues like cloud cover, atmospheric effects, and sensor variations. Results on test sites show the HMM can produce forest cover maps and detect changes over decades using Landsat and other data.
Ill-posedness formulation of the emission source localization in the radio- d...Ahmed Ammar Rebai PhD
To contact the authors : tarek.salhi@gmail.com and ahmed.rebai2@gmail.com
In the field of radio detection in astroparticle physics, many studies have shown the strong dependence of the solution of the radio-transient sources localization problem (the radio-shower time of arrival on antennas) such solutions are purely numerical artifacts. Based on a detailed analysis of some already published results of radio-detection experiments like : CODALEMA 3 in France, AERA in Argentina and TREND in China, we demonstrate the ill-posed character of this problem in the sens of Hadamard. Two approaches have been used as the existence of solutions degeneration and the bad conditioning of the mathematical formulation problem. A comparison between experimental results and simulations have been made, to highlight the mathematical studies. Many properties of the non-linear least square function are discussed such as the configuration of the set of solutions and the bias.
3 - A critical review on the usual DCT Implementations (presented in a Malays...Youness Lahdili
1) The document reviews and compares various implementations of the Discrete Cosine Transform (DCT), which is widely used in video and image compression standards.
2) It finds that the Loeffler algorithm achieves the theoretical minimum of 11 multiplications for an 8-point DCT, while the Arai algorithm requires only 5 multiplications and 29 additions.
3) The document concludes that while the DCT has been very successful, other transforms like the Discrete Wavelet Transform used in the Daala standard may provide alternatives worth further research to reduce blocking artifacts at high compression.
Computational Method to Solve the Partial Differential Equations (PDEs)Dr. Khurram Mehboob
This document discusses various computational methods for solving partial differential equations (PDEs) using MATLAB. It begins by introducing three types of PDEs - elliptic, parabolic, and hyperbolic - and provides examples of each. It then describes explicit methods like the Forward Time Centered Space (FTCS) method, Lax method, and Crank-Nicolson (CTCS) method for solving the advection equation. The document provides MATLAB code implementing these methods for a test case of solving the advection equation modeling a square wave.
Parallelization of molecular dynamics simulations allows for longer timescales to be reached. There are two main approaches to parallelization - replicated data and domain decomposition. Domain decomposition divides the simulation space into subdomains and assigns particles to processors to minimize communication costs. It provides better parallel efficiency than replicated data. Popular molecular dynamics codes like GROMACS and NAMD use domain decomposition approaches. Efficient parallelization of the reciprocal space calculation in particle-mesh Ewald methods is also important for performance. Two-dimensional decomposition of the 3D fast Fourier transforms provides higher parallel scaling than one-dimensional decomposition.
Complex Background Subtraction Using Kalman FilterIJERA Editor
Background subtraction from dynamic background, At any location of the scene, this system extract a sequence of regular video bricks, i.e., video volumes spanning over both spatial and temporal domain. The background modeling is thus posed as pursuing subspaces within the video bricks while adapting the scene variations. For each sequence of video bricks, it pursues the subspace by employing the auto regressive moving average model that jointly characterizes the appearance consistency and temporal coherence of the observations. During online processing, it use tracking algorithm kalman’s filter for background/foreground classification and incrementally update the subspaces to cope with disturbances from foreground objects and scene changes.
Molecular dynamics (MD) is a very useful tool to understand various phenomena in atomistic detail. In MD, we can overcome the size- and time-scale problems by efficient parallelization. In this lecture, I’ll explain various parallelization methods of MD with some examples of GENESIS MD software optimization on Fugaku.
Using Subspace Pursuit Algorithm to Improve Performance of the Distributed Co...Polytechnique Montreal
This paper applies a compressed algorithm to improve the spectrum sensing performance of cognitive radio technology.
At the fusion center, the recovery error in the analog to information converter (AIC) when reconstructing the
transmit signal from the received time-discrete signal causes degradation of the detection performance. Therefore, we
propose a subspace pursuit (SP) algorithm to reduce the recovery error and thereby enhance the detection performance.
In this study, we employ a wide-band, low SNR, distributed compressed sensing regime to analyze and evaluate the
proposed approach. Simulations are provided to demonstrate the performance of the proposed algorithm.
SEQUENTIAL CLUSTERING-BASED EVENT DETECTION FOR NONINTRUSIVE LOAD MONITORINGcsandit
The problem of change-point detection has been well studied and adopted in many signal processing applications. In such applications, the informative segments of the signal are the
stationary ones before and after the change-point. However, for some novel signal processing and machine learning applications such as Non-Intrusive Load Monitoring (NILM), the information contained in the non-stationary transient intervals is of equal or even more importance to the recognition process. In this paper, we introduce a novel clustering-based sequential detection of abrupt changes in an aggregate electricity consumption profile with
accurate decomposition of the input signal into stationary and non-stationary segments. We also introduce various event models in the context of clustering analysis. The proposed algorithm is applied to building-level energy profiles with promising results for the residential BLUED power dataset.
Study o horizontal flows in solar active regionsastrosanti
This thesis work can be framed in a more general concept designated as "high-solution in solar physics". The work consists of two clearly defined parts. The first part concerning instrumental developments for solar observations and the second one devoted to the scientific exploitation of solar data acquired with cutting edge solar instrumentation.
The document discusses applying probabilistic localization and SLAM algorithms to a marine robotic middleware. It presents using Monte Carlo localization to estimate a vehicle's position based on range measurements to known beacons. It also applies FastSLAM to simultaneously estimate the vehicle position and map unknown beacon locations. Results show both algorithms accurately estimate positions, apart from an initial offset in FastSLAM, demonstrating their effectiveness for marine robot localization and mapping.
DTAM: Dense Tracking and Mapping in Real-Time, Robot vision GroupLihang Li
This is the slides about DTAM for my group meeting report, hope it does help to anyone who will want to implement DTAM and need to understand it deeply.
Achieving undelayed initialization in monocular slam with generalized objects...Chen-Han Hsiao
This document summarizes a research paper on achieving undelayed initialization in monocular simultaneous localization and mapping (SLAM) with generalized objects. The researchers propose a simple yet effective static and moving object classification method using velocity estimates directly from SLAM with GO. A new feature is classified as stationary or moving using two thresholds based on its estimated velocity. This allows all observations to be used for state estimation without delay, improving the accuracy of monocular SLAM with GO. Both simulations and real experiments demonstrate the effectiveness of the proposed classification approach.
This document discusses several numerical methods for solving partial differential equations (PDEs) using Mathematica and MATLAB. It covers finite difference methods like FTCS, Lax, Crank-Nicolson for parabolic PDEs. It also discusses Jacobi's method, SOR method for elliptic PDEs and finite difference schemes for hyperbolic PDEs. MATLAB code examples are provided to implement these methods for different PDEs like heat equation, wave equation and Poisson's equation.
This document describes a virtual point light (VPL) rendering technique that uses a Metropolis sampling algorithm to efficiently approximate global illumination in scenes. The technique converts indirect lighting computed by a path tracer into virtual point lights that are rendered in real-time using a GPU. This allows for interactive rendering speeds while still achieving results close to a conventional path tracer. The key aspects of the VPL technique and Metropolis sampling algorithm are discussed, and details of the implementation including VPL generation, shadow mapping, and a shader chain for flexible material modeling are provided.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation
of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a
49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
New folderelec425_2016_hw5.pdfMar 25, 2016 ELEC 425 S.docxcurwenmichaela
The document discusses omnidirectional reflection from a one-dimensional photonic crystal structure. It presents the following key points:
1) A one-dimensional photonic crystal, such as a multilayer film, can exhibit complete reflection of light within a frequency range for all incident angles and polarizations, even without a full photonic bandgap.
2) The criterion for omnidirectional reflection is that there exists a frequency range where the projected band structures of the photonic crystal and surrounding medium do not overlap, rather than there being no propagating states within the crystal itself.
3) As an example, a multilayer film with refractive indices of n1 = 1.7 and n2 = 3.4
SLAM of Multi-Robot System Considering Its Network Topologytoukaigi
This document proposes a new solution to the multi-robot simultaneous localization and mapping (SLAM) problem that takes into account the network topology between robots. Previous multi-robot SLAM research has expanded one-robot SLAM algorithms without considering how the relationship between robots changes over time. The proposed approach models the network structure and derives the mathematical formulation for estimating the multi-robot SLAM. It presents motion and observation update equations in an information filter framework that can be implemented in a decentralized way on individual robots. Future work will focus on specific challenges in multi-robot SLAM like map merging.
Deep learning models can be improved for physical processes by incorporating prior scientific knowledge. The paper proposes a method where a neural network predicts parameters like motion fields in governing equations, rather than directly predicting outputs. It applies this to ocean surface temperature prediction. The model predicts a motion field from past temperature images using a CNN. It then uses this motion field in a warping scheme based on the advection-diffusion equation to forecast future temperature. This outperforms comparison methods by leveraging physics knowledge without requiring manual specification of equations.
TWO DIMENSIONAL MODELING OF NONUNIFORMLY DOPED MESFET UNDER ILLUMINATIONVLSICS Design
A two dimensional numerical model of an optically gated GaAs MESFET with non uniform channel doping has been developed. This is done to characterize the device as a photo detector. First photo induced voltage (Vop) at the Schottky gate is calculated for estimating the channel profile. Then Poisson’s equation for the device is solved numerically under dark and illumination condition. The paper aims at developing the MESFET 2-D model under illumination using Monte Carlo Finite Difference method. The results discuss about the optical potential developed in the device, variation of channel potential under different biasing and illumination and also about electric fields along X and Y directions. The Cgs under different illumination is also calculated. It has been observed from the results that the characteristics of the device are strongly influenced by the incident optical illumination.
COMPLEMENTARY VISION BASED DATA FUSION FOR ROBUST POSITIONING AND DIRECTED FL...ijaia
The present paper describes an improved 4 DOF (x/y/z/yaw) vision based positioning solution for fully 6
DOF autonomous UAVs, optimised in terms of computation and development costs as well as robustness
and performance. The positioning system combines Fourier transform-based image registration (Fourier
Tracking) and differential optical flow computation to overcome the drawbacks of a single approach. The
first method is capable of recognizing movement in four degree of freedom under variable lighting conditions, but suffers from low sample rate and high computational costs. Differential optical flow computation, on the other hand, enables a very high sample rate to gain control robustness. This method, however, is limited to translational movement only and performs poor in bad lighting conditions. A reliable positioning system for autonomous flights with free heading is obtained by fusing both techniques. Although the vision system can measure the variable altitude during flight, infrared and ultrasonic sensors are used for robustness. This work is part of the AQopterI8 project, which aims to develop an autonomous
flying quadrocopter for indoor application and makes autonomous directed flight possible.
The document discusses using a hidden Markov model to analyze temporal changes in forest cover from satellite imagery over time. It outlines how the HMM can model land cover classes and transitions between classes over multiple time steps. The HMM finds the most likely sequence of land cover classes for each pixel location using algorithms like Viterbi or forward-backward. This allows analyzing a time series of images while handling issues like cloud cover, atmospheric effects, and sensor variations. Results on test sites show the HMM can produce forest cover maps and detect changes over decades using Landsat and other data.
Ill-posedness formulation of the emission source localization in the radio- d...Ahmed Ammar Rebai PhD
To contact the authors : tarek.salhi@gmail.com and ahmed.rebai2@gmail.com
In the field of radio detection in astroparticle physics, many studies have shown the strong dependence of the solution of the radio-transient sources localization problem (the radio-shower time of arrival on antennas) such solutions are purely numerical artifacts. Based on a detailed analysis of some already published results of radio-detection experiments like : CODALEMA 3 in France, AERA in Argentina and TREND in China, we demonstrate the ill-posed character of this problem in the sens of Hadamard. Two approaches have been used as the existence of solutions degeneration and the bad conditioning of the mathematical formulation problem. A comparison between experimental results and simulations have been made, to highlight the mathematical studies. Many properties of the non-linear least square function are discussed such as the configuration of the set of solutions and the bias.
3 - A critical review on the usual DCT Implementations (presented in a Malays...Youness Lahdili
1) The document reviews and compares various implementations of the Discrete Cosine Transform (DCT), which is widely used in video and image compression standards.
2) It finds that the Loeffler algorithm achieves the theoretical minimum of 11 multiplications for an 8-point DCT, while the Arai algorithm requires only 5 multiplications and 29 additions.
3) The document concludes that while the DCT has been very successful, other transforms like the Discrete Wavelet Transform used in the Daala standard may provide alternatives worth further research to reduce blocking artifacts at high compression.
Computational Method to Solve the Partial Differential Equations (PDEs)Dr. Khurram Mehboob
This document discusses various computational methods for solving partial differential equations (PDEs) using MATLAB. It begins by introducing three types of PDEs - elliptic, parabolic, and hyperbolic - and provides examples of each. It then describes explicit methods like the Forward Time Centered Space (FTCS) method, Lax method, and Crank-Nicolson (CTCS) method for solving the advection equation. The document provides MATLAB code implementing these methods for a test case of solving the advection equation modeling a square wave.
Parallelization of molecular dynamics simulations allows for longer timescales to be reached. There are two main approaches to parallelization - replicated data and domain decomposition. Domain decomposition divides the simulation space into subdomains and assigns particles to processors to minimize communication costs. It provides better parallel efficiency than replicated data. Popular molecular dynamics codes like GROMACS and NAMD use domain decomposition approaches. Efficient parallelization of the reciprocal space calculation in particle-mesh Ewald methods is also important for performance. Two-dimensional decomposition of the 3D fast Fourier transforms provides higher parallel scaling than one-dimensional decomposition.
Complex Background Subtraction Using Kalman FilterIJERA Editor
Background subtraction from dynamic background, At any location of the scene, this system extract a sequence of regular video bricks, i.e., video volumes spanning over both spatial and temporal domain. The background modeling is thus posed as pursuing subspaces within the video bricks while adapting the scene variations. For each sequence of video bricks, it pursues the subspace by employing the auto regressive moving average model that jointly characterizes the appearance consistency and temporal coherence of the observations. During online processing, it use tracking algorithm kalman’s filter for background/foreground classification and incrementally update the subspaces to cope with disturbances from foreground objects and scene changes.
Molecular dynamics (MD) is a very useful tool to understand various phenomena in atomistic detail. In MD, we can overcome the size- and time-scale problems by efficient parallelization. In this lecture, I’ll explain various parallelization methods of MD with some examples of GENESIS MD software optimization on Fugaku.
Using Subspace Pursuit Algorithm to Improve Performance of the Distributed Co...Polytechnique Montreal
This paper applies a compressed algorithm to improve the spectrum sensing performance of cognitive radio technology.
At the fusion center, the recovery error in the analog to information converter (AIC) when reconstructing the
transmit signal from the received time-discrete signal causes degradation of the detection performance. Therefore, we
propose a subspace pursuit (SP) algorithm to reduce the recovery error and thereby enhance the detection performance.
In this study, we employ a wide-band, low SNR, distributed compressed sensing regime to analyze and evaluate the
proposed approach. Simulations are provided to demonstrate the performance of the proposed algorithm.
SEQUENTIAL CLUSTERING-BASED EVENT DETECTION FOR NONINTRUSIVE LOAD MONITORINGcsandit
The problem of change-point detection has been well studied and adopted in many signal processing applications. In such applications, the informative segments of the signal are the
stationary ones before and after the change-point. However, for some novel signal processing and machine learning applications such as Non-Intrusive Load Monitoring (NILM), the information contained in the non-stationary transient intervals is of equal or even more importance to the recognition process. In this paper, we introduce a novel clustering-based sequential detection of abrupt changes in an aggregate electricity consumption profile with
accurate decomposition of the input signal into stationary and non-stationary segments. We also introduce various event models in the context of clustering analysis. The proposed algorithm is applied to building-level energy profiles with promising results for the residential BLUED power dataset.
Study o horizontal flows in solar active regionsastrosanti
This thesis work can be framed in a more general concept designated as "high-solution in solar physics". The work consists of two clearly defined parts. The first part concerning instrumental developments for solar observations and the second one devoted to the scientific exploitation of solar data acquired with cutting edge solar instrumentation.
The document discusses applying probabilistic localization and SLAM algorithms to a marine robotic middleware. It presents using Monte Carlo localization to estimate a vehicle's position based on range measurements to known beacons. It also applies FastSLAM to simultaneously estimate the vehicle position and map unknown beacon locations. Results show both algorithms accurately estimate positions, apart from an initial offset in FastSLAM, demonstrating their effectiveness for marine robot localization and mapping.
DTAM: Dense Tracking and Mapping in Real-Time, Robot vision GroupLihang Li
This is the slides about DTAM for my group meeting report, hope it does help to anyone who will want to implement DTAM and need to understand it deeply.
Achieving undelayed initialization in monocular slam with generalized objects...Chen-Han Hsiao
This document summarizes a research paper on achieving undelayed initialization in monocular simultaneous localization and mapping (SLAM) with generalized objects. The researchers propose a simple yet effective static and moving object classification method using velocity estimates directly from SLAM with GO. A new feature is classified as stationary or moving using two thresholds based on its estimated velocity. This allows all observations to be used for state estimation without delay, improving the accuracy of monocular SLAM with GO. Both simulations and real experiments demonstrate the effectiveness of the proposed classification approach.
This document discusses several numerical methods for solving partial differential equations (PDEs) using Mathematica and MATLAB. It covers finite difference methods like FTCS, Lax, Crank-Nicolson for parabolic PDEs. It also discusses Jacobi's method, SOR method for elliptic PDEs and finite difference schemes for hyperbolic PDEs. MATLAB code examples are provided to implement these methods for different PDEs like heat equation, wave equation and Poisson's equation.
This document describes a virtual point light (VPL) rendering technique that uses a Metropolis sampling algorithm to efficiently approximate global illumination in scenes. The technique converts indirect lighting computed by a path tracer into virtual point lights that are rendered in real-time using a GPU. This allows for interactive rendering speeds while still achieving results close to a conventional path tracer. The key aspects of the VPL technique and Metropolis sampling algorithm are discussed, and details of the implementation including VPL generation, shadow mapping, and a shader chain for flexible material modeling are provided.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation
of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a
49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
New folderelec425_2016_hw5.pdfMar 25, 2016 ELEC 425 S.docxcurwenmichaela
The document discusses omnidirectional reflection from a one-dimensional photonic crystal structure. It presents the following key points:
1) A one-dimensional photonic crystal, such as a multilayer film, can exhibit complete reflection of light within a frequency range for all incident angles and polarizations, even without a full photonic bandgap.
2) The criterion for omnidirectional reflection is that there exists a frequency range where the projected band structures of the photonic crystal and surrounding medium do not overlap, rather than there being no propagating states within the crystal itself.
3) As an example, a multilayer film with refractive indices of n1 = 1.7 and n2 = 3.4
SLAM of Multi-Robot System Considering Its Network Topologytoukaigi
This document proposes a new solution to the multi-robot simultaneous localization and mapping (SLAM) problem that takes into account the network topology between robots. Previous multi-robot SLAM research has expanded one-robot SLAM algorithms without considering how the relationship between robots changes over time. The proposed approach models the network structure and derives the mathematical formulation for estimating the multi-robot SLAM. It presents motion and observation update equations in an information filter framework that can be implemented in a decentralized way on individual robots. Future work will focus on specific challenges in multi-robot SLAM like map merging.
Deep learning models can be improved for physical processes by incorporating prior scientific knowledge. The paper proposes a method where a neural network predicts parameters like motion fields in governing equations, rather than directly predicting outputs. It applies this to ocean surface temperature prediction. The model predicts a motion field from past temperature images using a CNN. It then uses this motion field in a warping scheme based on the advection-diffusion equation to forecast future temperature. This outperforms comparison methods by leveraging physics knowledge without requiring manual specification of equations.
TWO DIMENSIONAL MODELING OF NONUNIFORMLY DOPED MESFET UNDER ILLUMINATIONVLSICS Design
A two dimensional numerical model of an optically gated GaAs MESFET with non uniform channel doping has been developed. This is done to characterize the device as a photo detector. First photo induced voltage (Vop) at the Schottky gate is calculated for estimating the channel profile. Then Poisson’s equation for the device is solved numerically under dark and illumination condition. The paper aims at developing the MESFET 2-D model under illumination using Monte Carlo Finite Difference method. The results discuss about the optical potential developed in the device, variation of channel potential under different biasing and illumination and also about electric fields along X and Y directions. The Cgs under different illumination is also calculated. It has been observed from the results that the characteristics of the device are strongly influenced by the incident optical illumination.
Seismic data processing 15, kirchhof migrationAmin khalil
Kirchhoff migration is a widely used seismic data processing method. It works by back projecting observed seismic event energy from traces to possible subsurface reflection points based on traveltime. This smears the event energy to all possible subsurface locations, generating artifacts. Stacking multiple migrated traces helps resolve the true dipping reflector. Ray tracing is used to build the traveltime field. Kirchhoff migration is computationally expensive, taking days to process post-stack or months for pre-stack data. Representing the earth in 3D rather than 2D is preferable but requires knowing the 3D velocity model which is challenging.
Two Dimensional Modeling of Nonuniformly Doped MESFET Under IlluminationVLSICS Design
A two dimensional numerical model of an optically gated GaAs MESFET with non uniform channel doping has been developed. This is done to characterize the device as a photo detector. First photo induced voltage (Vop) at the Schottky gate is calculated for estimating the channel profile. Then Poisson’s equation for the device is solved numerically under dark and illumination condition. The paper aims at developing the MESFET 2-D model under illumination using Monte Carlo Finite Difference method. The results discuss about the optical potential developed in the device, variation of channel potential under different biasing and illumination and also about electric fields along X and Y directions. The Cgs under different illumination is also calculated. It has been observed from the results that the characteristics of the device are strongly influenced by the incident optical illumination.
This document discusses the application of a lattice-Boltzmann computational fluid dynamics (CFD) code for automobile and motorcycle aerodynamics simulations at BMW. It begins by explaining how CFD is used alongside wind tunnel testing to analyze vehicle designs earlier in the development process. It then provides details on the lattice-Boltzmann method, including describing the mesoscopic approach, kinetic theory, and the concepts of the lattice model. The document explains how macroscopic fluid properties emerge from microscopic particle distributions and collisions in the model.
This document describes the implementation of an Extended Kalman Filter (EKF) to estimate the state (position and heading angle) of a bicycle model. The EKF was able to provide reasonably accurate estimates of position over time based on position measurements and steering/velocity inputs, but struggled to accurately estimate the heading angle due to a lack of direct measurements. Histograms of the final state errors across many test cases showed normally distributed position errors and a uniformly distributed random heading angle error. While the EKF provided an approximation, a more advanced filter may have yielded better heading angle estimates.
2006 Green Incorporating Pulse to Pulse Motion Effects anto Side Looking Arra...Justin Green
This document presents a technique for incorporating pulse-to-pulse motion effects into side-looking array radar data models. The technique accounts for changes in platform attitude between pulses, which affects the geometry between the radar and targets. It uses coordinate transformations to describe how the platform orientation changes with each pulse. This allows calculation of pulse-dependent parameters like spatial frequency and Doppler, extending the existing radar data model to be sensitive to platform motion. The new motion-sensitive space-time snapshot can then be used to characterize how motion impacts the performance of space-time adaptive processing algorithms.
Object tracking is one of the most important problems in modern visual systems and researches are
continuing their studies in this field. A suitable tracking method should not only be able to recognize and
track the related object in continuous frames, but should also provide a reliable and efficient reaction
against the phenomena disturbing tracking process including performance efficiency in real-time
applications. In this article, an effective mesh-based method is introduced as a suitable tracking method in
continuous frames. Also, its preference and limitation is discussed.
This document presents an adaptive mesh method for object tracking in video frames. The method uses an adaptive mesh structure instead of a uniform mesh, where nodes are selected adaptively between frames based on object movement. This provides more robustness to minor or major occlusions. The method estimates background to be covered and uncovered background regions, applies polygon approximation to model borders, and estimates optical flow for node movement. It was shown to effectively handle challenges in tracking like occlusions while maintaining real-time performance. Some limitations are its complexity and inability to guarantee occlusion of all inter-nodal regions.
This document describes two techniques for designing optical XNOR and NAND logic gates. The first technique uses a 2D array of coupled optical cavities with Kerr nonlinearity. Discrete cavity solitons are numerically simulated and used to demonstrate optical XNOR and NAND gates by controlling soliton interactions with a Gaussian beam. The second technique uses multi-mode interference waveguides to convert the phase of binary-phase-shift keying input signals to amplitude at the output, implementing optical XNOR and NAND logic. Numerical simulations using the finite element method show contrast ratios of 21.5 dB for the XNOR gate and 22.3 dB for the NAND gate.
DESPECKLING OF SAR IMAGES BY OPTIMIZING AVERAGED POWER SPECTRAL VALUE IN CURV...ijistjournal
The document describes a novel algorithm for despeckling synthetic aperture radar (SAR) images using particle swarm optimization (PSO) in the curvelet domain. The algorithm first identifies homogeneous regions in the speckled image using variance calculations. It then uses PSO to optimize the thresholding of curvelet coefficients, with the objective of minimizing the average power spectral value. This provides an optimized threshold to apply curvelet-based despeckling. The proposed method is tested on standard images and shown to outperform conventional filters like median and Lee filters in reducing speckle noise.
DESPECKLING OF SAR IMAGES BY OPTIMIZING AVERAGED POWER SPECTRAL VALUE IN CURV...ijistjournal
Synthetic Aperture Radar (SAR) images are inherently affected by multiplicative speckle noise, due to the coherent nature of scattering phenomena. In this paper, a novel algorithm capable of suppressing speckle noise using Particle Swarm Optimization (PSO) technique is presented. The algorithm initially identifies homogenous region from the corrupted image and uses PSO to optimize the Thresholding of curvelet coefficients to recover the original image. Average Power Spectrum Value (APSV) has been used as objective function of PSO. The Proposed algorithm removes Speckle noise effectively and the performance of the algorithm is tested and compared with Mean filter, Median filter, Lee filter, Statistic Lee filter, Kuan filter, frost filter and gamma filter., outperforming conventional filtering methods.
This document summarizes an electrical engineering student's final project report on using an Unscented Kalman Filter (UKF) to estimate the state of a balancing robot. The UKF was able to accurately track states and uncertainties in simulation, but had difficulty estimating the true robot length from experimental datasets, likely due to insufficient oscillation of the robot. While the UKF and Extended KF agreed on the estimated length, more accurate methods may be needed such as Monte Carlo simulation with more samples.
A Novel Space-time Discontinuous Galerkin Method for Solving of One-dimension...TELKOMNIKA JOURNAL
In this paper we propose a high-order space-time discontinuous Galerkin (STDG) method for
solving of one-dimensional electromagnetic wave propagations in homogeneous medium. The STDG
method uses finite element Discontinuous Galerkin discretizations in spatial and temporal domain
simultaneously with high order piecewise Jacobi polynomial as the basis functions. The algebraic
equations are solved using Block Gauss-Seidel iteratively in each time step. The STDG method is
unconditionally stable, so the CFL number can be chosen arbitrarily. Numerical examples show that the
proposed STDG method is of exponentially accuracy in time.
A novel and efficient mixed-signal compressed sensing for wide-band cognitive...Polytechnique Montreal
In cognitive radio (CR) networks, unlicensed (cognitive) users can exploit the licensed frequency bands by using spectrum sensing techniques to identify spectrum holes. This paper proposes a distributed compressive spectrum sensing scheme, in which the modulated wide-band converter can apply compressed sensing (CS) directly to analog signals at the sub-Nyquist rate and the central fusion receives signals from multiple CRs and exploits the multiple-measurements-vectors (MMV) subspace pursuit (M-SP) algorithm to jointly reconstruct the spectral support of the wide-band signal. This support is then used to detect whether the licensed bands are occupy or not. Finally, extensive simulation results show the advantages of the proposed scheme. Besides, we also compare the performance of M-SP with M-orthogonal matching pursuit (M-OMP) algorithms.
APPLICATION OF PARTICLE SWARM OPTIMIZATION TO MICROWAVE TAPERED MICROSTRIP LINEScseij
This document discusses using Particle Swarm Optimization (PSO) to design a tapered microstrip transmission line to match an arbitrary load to a 50Ω line. PSO was used to optimize the impedances of a three section tapered line to minimize reflections. Simulations found impedances that gave good matching at 5GHz. PSO converged to solutions in under 1000 iterations. This demonstrates PSO's effectiveness in solving multi-objective microwave engineering optimization problems.
Application of particle swarm optimization to microwave tapered microstrip linescseij
Application of metaheuristic algorithms has been of continued interest in the field of electrical engineering
because of their powerful features. In this work special design is done for a tapered transmission line used
for matching an arbitrary real load to a 50Ω line. The problem at hand is to match this arbitray load to 50
Ω line using three section tapered transmission line with impedances in decreasing order from the load. So
the problem becomes optimizing an equation with three unknowns with various conditions. The optimized
values are obtained using Particle Swarm Optimization. It can easily be shown that PSO is very strong in
solving this kind of multiobjective optimization problems.
Compressive Light Field Photography using Overcomplete Dictionaries and Optim...Ankit Thiranh
In this paper, a design is proposed for a compressive light field camera which will allow to recover light fields with higher resolution from a single image. Also, various other useful applications for light field atoms are discussed, including 4D light field compression and denoising.
Similar to Smear correction of highly variable, (20)
Este documento presenta una introducción a la administración japonesa. Describe las principales teorías administrativas japonesas como la Teoría Z, Calidad Total, Kaizen, Kanban y Justo a Tiempo. También discute los elementos clave de la filosofía administrativa de Konosuke Matsushita y las características distintivas de la administración japonesa como la mano de obra calificada y comprometida. Finalmente, concluye que la estrategia es fundamental para el éxito cuando la competencia es fuerte.
La pandemia de COVID-19 ha tenido un impacto significativo en la economía mundial y las vidas de las personas. Muchos países han impuesto medidas de confinamiento que han cerrado negocios y escuelas. A medida que los países comienzan a reabrir gradualmente, existen desafíos significativos para restaurar la confianza de los consumidores y revivir las economías.
Este documento describe los fluidos tixotrópicos, los cuales tienen una viscosidad que disminuye con el tiempo de aplicación del esfuerzo cortante y recuperan su estado inicial después de un período de reposo. Explica que este comportamiento se debe a cambios en la estructura molecular del fluido bajo tensión, como el fraccionamiento y reconstitución de las partículas dispersas. También menciona ejemplos comunes de fluidos tixotrópicos y describe el fenómeno de histéresis que presentan.
Este documento presenta un solucionario para el libro "Ecuaciones Diferenciales Dennis G. Zill" que cubre los capítulos 2 al 7, incluyendo secciones específicas de cada capítulo sobre temas como ecuaciones diferenciales ordinarias de primer y segundo orden, series de potencias, ecuaciones lineales de segundo orden, y ecuaciones en derivadas parciales. El documento proporciona una dirección web para acceder al solucionario.
1) El documento describe los fundamentos de la espectroscopia infrarroja y ultravioleta-visible para la determinación de estructuras orgánicas, incluyendo las regiones del espectro infrarrojo, los modos fundamentales de vibración molecular y las absorciones características de grupos funcionales. 2) Explica que la espectroscopia infrarroja se utiliza para estudiar las vibraciones moleculares mientras que la ultravioleta-visible estudia las transiciones electrónicas, y proporciona ejemplos de absorciones caracter
1) Para una partícula en una caja 1D, las reglas de selección permiten transiciones entre estados de paridad opuesta (n par a n impar y viceversa) y prohíben transiciones entre estados de la misma paridad.
2) Para una partícula en una caja 3D expuesta a radiación isotrópica, el momento dipolar eléctrico se descompone en sus componentes cartesianas y solo habrá transición si los estados inicial y final difieren en un solo número cuántico (nx, ny o nz).
3) El espectro de
Este documento describe el uso de la espectroscopia infrarroja por transformada de Fourier (FTIR) para determinar los espectros de varios compuestos como la acetona, carbonato de calcio, etanol, glicerina y metanol. La espectroscopia infrarroja permite conocer los principales grupos funcionales de la estructura molecular de un compuesto a partir de su espectro de absorción infrarroja.
Este documento proporciona una introducción a la espectroscopia infrarroja. Explica que la espectroscopia infrarroja se basa en la absorción de radiación infrarroja por las moléculas debido a cambios en los estados vibracionales. Describe los diferentes modos de vibración molecular como stretching y bending. También cubre conceptos como los modos normales de vibración, las bandas activas en infrarrojo y la apariencia de las bandas en los espectros.
Este documento presenta una serie de ejercicios sobre espectroscopía infrarroja. Los ejercicios cubren temas como la identificación de grupos funcionales comunes, la determinación cuantitativa de concentraciones de reactivos y productos, la diferenciación de isómeros, y la asignación de picos en espectros IR a grupos y modos de vibración específicos. El objetivo general es que los estudiantes mejoren su comprensión de cómo se puede utilizar la espectroscopía infrarroja para caracterizar compuest
1. The study analyzed levels of minerals and trace elements in seeds, pulp, and skin of pumpkins from three regions in Guyana. Atomic absorption spectrophotometry was used to determine the concentration of elements in the samples.
2. Higher quantities of important minerals like iron, copper, zinc, and phosphorus were found in the seeds compared to the pulp and skin. The seed samples provided over 20% of the daily value for some of these minerals.
3. Concentrations of elements varied between the different pumpkin parts and growing regions, likely due to differences in soil composition and environmental conditions. However, the seeds were consistently shown to be a good source of several essential nutrients.
Aplicación de la Espectroscopia del Infrarrojo Medio en Química Analítica de...Juan Manuel Garcia Ayala
Este documento describe las aplicaciones de la espectroscopía infrarroja de transformada de Fourier (IRTF) en el análisis químico de procesos, centrándose en el control medioambiental y alimentario. Explica cómo la IRTF se ha utilizado para monitorizar contaminantes atmosféricos como emisiones industriales, gases de vehículos y volcanes. También describe aplicaciones en el control de alimentos y aguas.
La espectroscopia infrarroja tiene múltiples aplicaciones, incluyendo la caracterización e identificación de materiales como polímeros, plásticos, sólidos inorgánicos, productos farmacéuticos y de síntesis. También se usa para el análisis de contaminantes en ciencia forense, biomedicina para análisis de tejidos, conservación artística para análisis de pigmentos, la industria del reciclaje para identificación de polímeros, agricultura y alimentación, y para seguir proces
Este documento describe los sistemas de refrigeración y sus principios de funcionamiento. Explica que estos sistemas usan propiedades termodinámicas para transferir calor entre áreas de alta y baja temperatura con el fin de enfriar productos almacenados. Luego discute parámetros de diseño como temperaturas de operación, capacidad y refrigerantes, e identifica diferentes tipos de sistemas según el número de zonas frías. Finalmente, explica que la refrigeración por compresión funciona forzando el movimiento de un fluido a trav
Este documento presenta un problemario de termodinámica aplicada con el objetivo de mejorar el aprovechamiento de la asignatura. Contiene una introducción donde se explica la motivación y objetivos del problemario, así como recomendaciones para su uso. Además, incluye conceptos fundamentales de termodinámica necesarios para comprender y resolver los problemas propuestos. Finalmente, presenta una serie de problemas de diferentes temas como relaciones termodinámicas, ecuaciones de estado, mezclas de gases, combustión y soluciones ideales.
This article aims to classify wines based on their UV-visible spectra and color characteristics using multivariate statistical analysis. A total of 63 red wines and 28 white wines from Turkey from 2006-2009 vintages were analyzed for their color parameters, total anthocyanin content, and UV-visible absorbance spectra. Principal component analysis and orthogonal partial least squares-discriminant analysis were able to differentiate the wines based on variety and vintage with 100% and 75% accuracy, respectively, showing the potential of using combined spectral and color data for wine authentication.
El documento describe los diferentes regímenes de flujo de fluidos en tuberías, incluyendo flujo laminar, turbulento y de transición. Explica que el número de Reynolds relaciona las propiedades del fluido y la geometría de la tubería para predecir el tipo de flujo. También cubre brevemente los instrumentos comunes para medir la presión de los fluidos, como los manómetros de tubo de Bourdon y los barómetros.
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
2. Research Article Applied Optics 2
lowing sections are restricted to a single sensor column without
losing generality.
Fig. 1 illustrates the operation in standard mode of a CCD
with M rows during the acquisition of a single pixel in row no.
m of frame no. k. The upper sketch represents the position of
charge well no. m within the column. The lower profile ex-
emplifies the values of the photo charges flux in pixel no. m as
function of time, Sm(t). The considered frame extends from
time instants tk to tk+1 with tk+1 − tk being the reciprocal of
the CCD frame rate. The sensor is assumed to be permanently
illuminated. The black boxes delimit the intervals where frame
transfers are performed.
Fig. 1. Process required to acquire pixel no. m of frame no. k,
in a frame transfer CCD with M rows operating in standard
mode. Upper sketch illustrates the position within the column
of charge well no. m during frame acquisition. The lower pro-
file exemplifies the model we adopted for the photo charges
flux at pixel no. m, Sm(t). Namely constant during frame trans-
fer (black boxes with duration Mtt) and exposure time (te),
and variable during switching time (ts). The transition profile
is assumed symmetric with respect to the point (black circle)
with coordinates {tk+1 − ts/2, (Sk
m + Sk+1
m )/2}. See the text for
additional details.
Acquisition of frame no. k starts during the transfer of frame
no. k − 1. An empty charge well is shifted from the top of the ar-
ray to position no. m during a fraction of the total frame transfer
time given by (M − m + 1)tt, where tt is the period of the charge
transfer clock. After this, static accumulation at position no. m
takes place during the exposure time, te. The flux is assumed to
be constant and equal to Sk
m during frame transfer and expo-
sure time. A transition of the flux to its constant value in the
next frame, Sk+1
m , is then contemplated. The flux transition oc-
curs during the switching time ts, with the charge well still at
position no. m. The flux transition profile is assumed to be
symmetric with respect to the point with Cartesian coordinates
{tk+1 − ts/2, (Sk
m + Sk+1
m )/2} in Fig. 1 (black circle). In the final
step, once the flux is stable again, the charge well is transfered
to the storage area of the sensor.
For the above-described process and neglecting noise contri-
butions (see Sections 2A and 3A), pixel saturation, charge trans-
fer inefficiencies and instabilities of the charge transfer clock,
the value of the smeared signal acquired in pixel no. m of frame
no. k can be expressed as,
ˆYk
m = r1tt
M−1
∑
j=m+1
gjSk
j + gmteSk
m +
1
2
gmts(Sk
m + Sk+1
m )+
dm(te + ts) + bm + r2tt
m−1
∑
j=0
gjSk+1
j + tt
M−1
∑
j=0
j=m
dj, (1)
where the time constants gj, dj and bj denote the gain, dark cur-
rent flux and bias of pixel no. j respectively. The two ad-hoc
coefficients r1 and r2, have been introduced to facilitate experi-
mental tuning of the model, e.g. to: contemplate possible differ-
ences in the photo-charges-generation efficiencies of the static
and transferring clocking states; compensate the effects of syn-
chronization errors between the CCD readout and flux switch-
ing; model other CCD operation modes; etc.
The simple form of the third term in the right hand side of
Eq. 1, which accounts for the signal accumulated during ts, is a
direct consequence of the symmetry restriction imposed on the
flux transition profile. The later has been defined by the applica-
tion that motivated this work. In spite of that, notice it also cov-
ers other cases of possible practical interest like very fast switch-
ing (step-like profile), linear switching (ramp-like profile), con-
stant illumination, etc.
In the following we will assume the acquired images have
been offset corrected using the dark frame,
ˆDm = dm(te + ts) + bm + tt
M−1
∑
j=0
j=m
dj, (2)
which in practice can be obtained by averaging a long sequence
of dark images, i.e. with Sm(t) = 0.
In addition, let us define the unsmeared signal acquired dur-
ing the static and constant illumination exposure as,
Yk
m = gmteSk
m (3)
and constants,
α =
ts
2te
, δ1 =
r1tt
te
and δ2 =
r2tt
te
. (4)
Note that Eq. 3 implies any gain table corrections should be
applied after the desmearing process (see Section 3).
Using Eq. 1-4 and redefining ˆYk
m − ˆDm as ˆYk
m, we can write a
smeared column of the sensor in matrix form as,
ˆYk
= AYk
+ BYk+1
, (5)
where, ˆYk = ˆYk
0 , ˆYk
1 , . . . , ˆYk
M−1
T
, Yk = Yk
0 , Yk
1 , . . . , Yk
M−1
T
,
A =
1 + α δ1 . . . δ1
0 1 + α . . . δ1
...
...
...
...
0 0 0 1 + α
, B =
α 0 . . . 0
δ2 α . . . 0
...
...
...
...
δ2 δ2 δ2 α
,
and the superscript T denotes the transpose.
Note that, an analogue analysis can be carried out for the
case where frame transfer takes place before the flux switching,
3. Research Article Applied Optics 3
deriving in a causal difference equation also with matrix coeffi-
cients A and B.
In case the value of tt it is not known and can not be directly
measured, some techniques have been developed to allow its
experimental estimation for specific scenarios [7, 12].
When operating the CCD in charge flush mode, the charge
wells of the light sensitive area are flushed after the frame trans-
fer is finished. Eq. 5 can be modified to model this scenario by
doing r1 = 0. In reverse clocking mode the wells of the light sen-
sitive area are transfered to a charge drain, located at the top of
the sensor, by means of a reverse clocking. The latter is done
after the usual frame transfer. To consider this case in Eq. 5, A
has to be replaced by AT and r1 and r2 adjusted appropriately
if the clock rates, or charge transfer inefficiencies, of the usual
frame transfer and reverse sweep are different.
A. Noise properties of the smeared images
To investigate the noise properties of the smearing process, we
consider the unsmeared columns in Eq. 5 as independent ran-
dom vectors. We also include an independent, additive noise
term, Nk to the right hand side of Eq. 5 to account for extra
noise sources added during or after the charge wells are read,
e.g. readout noise. For the above-described scenario one can
show that,
Var[ ˆYk
] = AVar[Yk
]AT
+ BVar[Yk+1
]BT
+ Var[Nk
]
Cov[ ˆYk
, ˆYk+1
] = BVar[Yk+1
]AT
,
(6)
where Var and Cov represent the variance-covariance and cross-
covariance operations respectively. Note that Eq. 6 evidences
the spatial and temporal correlation introduced by the smear-
ing process.
We further assume in Eq. 6, that Var[Yk+1] = γVar[Yk] with
γ ∈ R, e.g. due to photon noise variation between frames with
very different illumination levels. Then, a simple upper limit
for the noise degradation can be written as follows,
| Var[ ˆYk
] |≤ η | Var[Yk
] | + | Var[Nk
] |, (7)
where | . | denotes the euclidean matrix norm and,
η = (1 + α + 2Mδ1/π)2
+ γ(α + 2Mδ2/π)2
for M ≫ 1. (8)
In the latter we used the fact that A = (1 + α − δ1)I + δ1∆ and
B = (α − δ2)I + δ2∆T, where I is the MxM identity matrix and
∆ an MxM upper triangular matrix with ∆i,j = 1 for j ≥ i and
∆i,j = 0 for j < i.
Fig. 2 shows curves of
√
η versus Mδ for different values
of α and γ (with r1 = r2 = 1). When interpreting Figure 2,
and similar ones in the next section, recall that by definition
for a fixed frame rate and exposure time, the sum 2α + Mδ is
constant.
3. IMAGE RESTORATION
A. Non-periodic illumination
In this section we discuss the solution of Eq. 5 to
an arbitrary time series of smeared columns, ˆY =
( ˆY0)T, ( ˆY1)T, . . . , ( ˆYK−1)T
T
, with K ≥ 2 ∈ N. Given
the shape of matrices A and B, the restored columns,
¯Y = ( ¯Y0)T, ( ¯Y1)T, . . . , ( ¯YK−1)T
T
, can be efficiently ob-
tained by solving iteratively from pixel no. M − 1 to 0 and
frame no. K − 1 to 0 if the final condition, ¯YK, is known.
0 5 10 15 20
Mδ %
1.0
1.1
1.2
1.3
1.4
√η
α=0.0%
α=10.0%
γ=10.0
γ=1.0
γ=0.1
γ=10.0
γ=1.0
γ=0.1
Fig. 2. Upper boundary for the noise degradation due to the
smearing process, versus the parameters product Mδ. The
curves in each set, continuous for α = 0.0% and dotted for
α = 10.0%, correspond to γ = 0.1, 1.0 and 10.0 from bottom to
top respectively. See Eq. 7-8 for extra details.
M=512 and Mδ ∈{0.5, 7.0, 13.5, 20.0}%
0 1 2 3 4 5 6
K−k
10
−5
10
−4
10
−3
10
−2
10
−1
10
0
|H
K−k
|
Mδ=0.5%
Mδ=20.0%
α=0.0%
α=10.0%
Fig. 3. Upper boundary for the propagation of errors in the fi-
nal condition of Eq. 5, versus index of the restored frame. The
curves in each set, continuous for α = 0.0% and dotted for
α = 10.0%, correspond to Mδ = 0.5, 7.0, 13.5 and 20.0% from
left to right respectively
. Note the vertical axis is in logarithmic scale. See Eq. 9 for extra
details.
The difficulties to obtain ¯YK can be avoided after considering
the general solution of Eq. 5,
¯Yk
=
K−k
∑
j=1
HK−k−j
A−1 ˆYK−j
+ HK−k ¯YK
, (9)
where Hk = (−A−1B)k, has a highly damped homogeneous
term for practical values of its parameters. Note that we use
upper scripts of time independent matrices to denote exponen-
tiation. Fig. 3 presents | HK−k | as function of K − k. The curves
were computed for M = 512, although they are practically in-
sensitive to M for M >> 1, and different values of α and δ (with
r1 = r2 = 1). As can be appreciated, the error introduced by a
wrong estimation of the final condition, e.g. ¯YK = ˆYK−1, can be
reduced to negligible levels provided few frames at the end of
the series are dropped.
To study the overall conditioning of the restoration algo-
rithm, with respect to uncertainties in the measured columns,
4. Research Article Applied Optics 4
M=512, K=10 and α ∈{0, 4, 8, 12, 16, 20}%
0 5 10 15 20
Mδ %
1.00
1.02
1.04
1.06
1.08
1.10
1.12
1.14
Cond(U)
α=20%
α=0%
Fig. 4. Conditioning of the desmearing algorithm with respect
to errors in the measured images, versus the parameters prod-
uct Mδ. The curves correspond to α = 0, 4, 8, 12, 16 and 20%
from bottom to top respectively. See Eq. 10 for extra details.
let us write it using block matrices as follows (see Eq. 9),
¯Y = U ˆY + H ¯YK
, (10)
where H = (HK)T, (HK−1)T, . . . , (H1)T
T
,
U =
A−1 H1A−1 H2A−1 . . . HK−1A−1
0 A−1 H1A−1 . . . HK−2A−1
...
...
...
...
...
0 0 0 . . . A−1
,
and 0 is the M × M null matrix.
According to Eq. 10, when neglecting the contributions of
H ¯YK (see Fig. 3), the propagation of relative errors in the mea-
sured ˆY is upper bounded by the condition number of U, i.e.
the ratio of the largest to the smallest singular values of U [13].
The latter is plotted in Fig. 4 versus Mδ (with r1 = r2 = 1) for
M = 512, K = 10 and different values of α. The curves are
practically insensitive to M and K for M >> 1 and K >> 1. As
expected, the restoration becomes monotonically worse condi-
tioned for increasing δ and α.
B. Periodic illumination
Of particular interest for this work is the solution of Eq. 5 to a
time-periodic series of smeared columns, i.e. the illumination
pattern repeats cyclically after a fixed amount of frames. As-
suming periodicity in the scene allows the usage of image accu-
mulation for noise reduction purposes. This is specially impor-
tant for high-frame-rate applications that are photon starved.
In contrast to Section 3A, in the periodic illumination sce-
nario, image restoration can be performed for a single period of
the input, ˆY = ( ˆY0)T, ( ˆY1)T, . . . , ( ˆY
˜K−1)T
T
, where ˜K ≥ 2 ∈
N is the period. The corresponding desmearing expression can
be written in block matrix as,
¯Y = ˜U−1 ˆY, (11)
where,
˜U =
A B 0 . . . 0
0 A B . . . 0
...
...
...
...
...
B 0 0 . . . A
,
is a M ˜K × M ˜K, block circulant matrix [14]. Note Eq. 11 is linear
in ˆY and thus it can be applied after averaging any number of
periods, reducing this way the computational load.
On one hand, numeric inversion of ˜U will not be in general
a problem because it has to be done only once for each setup,
i.e. values of δ1, δ2 and α. There are, however, Fourier-based
methods used to invert block circulant matrices that can consid-
erably reduce computation time and storage while increasing
numeric stability [14, 15].
On the other hand, the product in the right side of Eq. 11
may become computationally expensive because it has to be
performed once per image column. Two possible approaches
to cope with this issue are: find only an approximate solution
iteratively by first guessing ˆY0 similar to Section 3A; or use the
fact that ˜U−1 is also block circulant and band dominant [15] to
implement an efficient multiplication algorithm.
4. APPLICATION TO FAST IMAGING POLARIMETRY
We applied the desmearing expression given in Section 3B to
correct a set of images taken by the Fast Solar Polarimeter (FSP)
[16]. We will not describe the instrument details here, only the
relevant aspects related to the image smearing process.
FSP uses a 264x264 pixels, split-frame-transfer pnCCD [17]
that can record up to 800 frames per second (fps). The pnCCD
operates in standard mode and its readout is synchronized with
a four-states beam modulator [18] that will introduce an inten-
sity variation according to the polarization state of the incom-
ing light. The intensity switching profiles and synchronization
between pnCCD and modulator meet the assumptions detailed
in section 2 for Eq. 5.
Any complete polarimetric measurement requires taking at
least four consecutive exposures, one during each modulator
state, that can have very different light levels for strongly polar-
ized sources. The four recorded frames are linearly combined
in a later step to retrieve the polarization signal. The sensor is
constantly illuminated during measurements. If the incoming
polarization state is constant, a periodic series of four images is
obtained.
The upper row of Fig. 5 presents an example measurement
taken at 700 fps of a USAF target illuminated by a light source
of constant linear polarization. Only a fraction of the total sen-
sor area is shown. Each of the four exposures, denoted with
labels State 1 to State 4, corresponds to an average of several
measurement periods. Smearing is obvious in all images, note
in particular its variable spatial distribution among different
states. The latter can be easily explained using Eq. 5 and con-
sidering that the mean light levels in the bright areas, i.e. above
two sigmas from the image mean, of each state are very differ-
ent. Namely 1950, 2828, 2825 and 297 arbitrary counts approxi-
mately for state 1 to state 4 respectively.
The lower row of Fig. 5 displays the restored images ob-
tained after applying Eq. 11 with ˜K = 4, M = 264, α = 3.9%,
δ1 = 0.05% and δ2 = 0.03% to the images in the upper row.
Reduction of the smearing is evident with only faint residuals.
5. Research Article Applied Optics 5
State 1 State 2 State 3 State 4
Fig. 5. Smeared (upper row) and corrected (lower row) im-
ages, displayed using logarithmic scales to enhance the smear-
ing. The gray scales of the images in each column are the same.
The mean values of the bright areas in the upper-row images
are 1950, 2828, 2825 and 297 arbitrary counts for states 1 to 4
respectively. The dashed and continuous horizontal lines in
states 3 and 4 images, delimit the cuts shown in Fig. 6
.
(a) State 3 horizontal cut
20 40 60 80 100
Pixels
0
1
2
3
4
5
6
Intensity%
Smear.
Corr.
Diff.
(b) State 4 horizontal stripe average
20 30 40 50 60
Pixels
0
2
4
6
8
10
12
14
Intensity%
Smear.
Corr.
Diff.
Fig. 6. Horizontal cut of the state 3 images (a) and vertical av-
erage of a 4-pixel-wide horizontal stripe of state 4 images (b).
The position of the cut and the center of stripe are indicated by
the dashed and continuous, white lines in Fig. 5. In both plots
the values for the smeared (dashed) and corrected (continu-
ous) images, as well as their difference (dotted) are shown. All
profiles are expressed in percentage of the mean value in the
bright areas of the corresponding smeared image.
The quality of the restoration and the differences in the arti-
fact levels between state 3 and state 4 images, are exemplified
by the profiles shown in Fig. 6. Firstly, from the corrected pro-
files, note there is not clear residual smearing above the noise
levels. Given the USAF target pattern, and in complete absence
of smearing and stray light, the profiles of the selected cuts are
expected to be flat except for noise induced variations.
Secondly, from the smeared profiles in Fig. 6, note that the
maximum artifact levels, relative to the mean in the bright ar-
eas of each image, are larger in State 4 (∼ 12%) than in State
3 (∼ 5%). To understand this, recall that each frame accu-
mulates smearing signal during both the pre-exposure and the
post-exposure frame transfers (see black boxes in Fig. 1). Fur-
ther, note that the smearing signal acquired during the post-
exposure transfer depends on the illumination level of the fol-
lowing frame. In this way, smearing level in State 3 is low
because the consecutive frame (state 4) has approximately 9.5
times fainter illumination. On the contrary, the artifact level in
State 4 is high because the consecutive frame (State 1, recall the
input is periodic) has approximately 6.6 times larger intensity.
5. CONCLUSIONS
We developed a model for the smearing, introduced in frame
transfer CCDs, that accounts for variations in the sensor illumi-
nation provided the changes take place in synchronization with
the detector readout and have a transition profile that is an odd
function. The derived model depends only on three physical
parameters, namely the period of the charge transfer clock, the
image exposure time and the photon flux switching time.
In addition, we showed that smearing introduces not only
a spatial but also a temporal correlation in the images and de-
rived a simple upper boundary for the noise degradation.
We also studied the corresponding desmearing algorithm
and its conditioning for the cases of non-periodic and periodic
variable scenes. The latter was successfully applied to restore
a set of polarimetric measurements taken by the Fast Solar Po-
larimeter.
The present work does not take in to account the effects of
pixel saturation, pixel blooming, and charge transfer inefficien-
cies.
F. A. Iglesias would like to acknowledge the International
Max Planck Research School for Solar System Science for sup-
porting his participation in this project.
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