arXiv subjects

Fatemeh Ahmadi

Publications and source records attributed to Fatemeh Ahmadi.

8 recordsLinked to original sources

arXiv2026

Clean Me If You Can: A Large Collection of Real-World Addresses for Data Cleaning Benchmarking

There has been extensive research on automating and scaling data cleaning, i.e., the detection and correction of erroneous values in tabular data. Yet, existing approaches often perform well only within controlled environments. One of the major bottlenecks in data cleaning research is the lack of real-world datasets. In this paper, we address this gap by providing a large, dirty dataset with postal entries and their corresponding ground truth. We discuss the design decisions and challenges for obtaining the dataset. We demonstrate the limitations of existing cleaning approaches when faced with our proposed datasets and derive guidelines for future research.

cs.DB↗

arXiv2025

Thermal quench of a dynamical QCD model in an external electric field

In this article, we investigate the thermal equilibration of the holographic QCD model dual to the Einstein-Maxwell-Dilaton (EMD) gravity in the presence of an external electric field. The model captures the QCD features at finite temperature and finite chemical potential in both confinement and deconfinement phases and could be considered a good candidate to study the dynamics of the strongly interacting system in out-of-equilibrium conditions. For this purpose, we examine the instability imposed by an external electric field using the AdS/CFT dictionary and study the electric current flow and its relaxation for this holographic model. We study the effects of temperature, electric field strength, and chemical potential on the current flow of the stationary state by applying a constant electric field. Additionally, for a time-dependent electric field, we investigate the relaxation time scales of the system using equilibration time. Finally, we compare our results with those from other holographic models and experiments.

hep-th↗

arXiv2024

Ricci flow-based brain surface covariance descriptors for diagnosing Alzheimer's disease

Automated feature extraction from MRI brain scans and diagnosis of Alzheimer's disease are ongoing challenges. With advances in 3D imaging technology, 3D data acquisition is becoming more viable and efficient than its 2D counterpart. Rather than using feature-based vectors, in this paper, for the first time, we suggest a pipeline to extract novel covariance-based descriptors from the cortical surface using the Ricci energy optimization. The covariance descriptors are components of the nonlinear manifold of symmetric positive-definite matrices, thus we focus on using the Gaussian radial basis function to apply manifold-based classification to the 3D shape problem. Applying this novel signature to the analysis of abnormal cortical brain morphometry allows for diagnosing Alzheimer's disease. Experimental studies performed on about two hundred 3D MRI brain models, gathered from Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset demonstrate the effectiveness of our descriptors in achieving remarkable classification accuracy.

eess.IV↗

arXiv2019

Application of image processing in optical method, Moire deflectometry for investigating the optical properties of zinc oxide nanoparticle

Nowadays for measurement of refractive index of nanomaterials usually spectro-photometric and mechanical methods are used which are expensive and indirect. In this paper for measuring these parameters of zinc oxide nanomaterial with two different stabilizers, a simple optical method, Moire deflectometry, which is based on wave front analysis and geometric optics is used. In the Moire deflectometry method, the beam of light from the laser diode passes through the sample. As a result of that, a change in the sample environment is observed as deflections of the fringes. By recording of these deflections using CCD and image processing with MATLAB, the nanomaterials refractive indices can be calculated. Due to the high accuracy of this method and improved the image processing code in Matlab, the smallest changes of the refractive index in the sample can be measured. Digital Image processing is used for processing images in a way that features can be selected and being shown. The results obtained in this method show a good improvement over the other used methods.

physics.ins-det↗

arXiv2017

The Particle-Field Theory and Its Relativistic Generalization

As a serious attempt for constructing a new foundation for describing micro-entities from a causal standpoint, it was explained before in [1, 2, 3] that by unifying the concepts of information, matter and energy, each micro-entity is assumed to be composed of a probability field joined to a particle called a particle-field or PF system. In this essay, the relativistic generalization of the PF theory has been considered. The equation of motion for the PF system is derived in a form which is Lorentz-invariant. Moreover, based on constitutional similarities to classical equations of motion, a well-defined relativistic time-independent Schrodinger equation is derived, which is one of our main achievements in developing a micro-relativistic physics of PF theory. This relativistic Schrodinger equation is solved for a relativistic micro-particle in one-dimensional box to find its eigenstate and energy spectrum.

quant-ph↗

arXiv2017

Particle-Field Theory and Its Relativistic Generalization II ( Relativistic Generalization of Micro Harmonic Oscillator and Hydrogen Atom )

As a serious attempt for constructing a new foundation for describing micro-entities from a causal standpoint, it was explained before in [1, 2, 3] that by unifying the concepts of information, matter and energy, each micro-entity is assumed to be composed of a probability field joined to a particle called a particle-field or PF system. The relativistic generalization of this theory and its invariance under Lorentz transformation has been proved. In this essay, based on the relativistic generalization of Schrodinger equation derived in [4], we solve the relativistic Schrodinger equation for relativistic micro-harmonic oscillator to find its energy. Also we obtain the energy spectrum of Hydrogen atom that is the main purpose of this paper. We see that the result is completely consistent with the relativistic correction to the Hydrogen's energy in first-order perturbation theory.

quant-ph↗

arXiv2014

Lorentz violation and red shift of gravitational waves in brane-worlds

In this paper we study the speed of gravitational waves in a brane world scenario and show that if the extra dimension is space-like, the speed of the propagation of such waves is greater in the bulk than that on the brane. Therefore, the 4D Lorentz invariance is broken in the gravitational sector. A comparison is also made between the red shift of such waves and those of the electromagnetic waves on the brane. Such a comparison is essential for extracting the signature of the extra dimension and thus clarifying the question of maximal velocity of gravitational waves in the bulk.

gr-qc↗

arXiv2014

Effect of GUP on the Kepler problem and a variable minimal length

Various approaches to quantum gravity, such as string theory, predict a minimal measurable length and a modification of the Heisenberg Uncertainty Principle near the Plank scale, known as the Generalized Uncertainty Principle (GUP). Here we study the effects of GUP which preserves the rotational symmetry of the spacetime, on the Kepler problem. By comparing the value of the perihelion shift of the planet Mercury in Schwarzschild-de Sitter spacetime with the resulted value of GUP, we find a relation between the minimal measurable length and the cosmological constant of the spacetime. Now, if the cosmological constant varies with time, we have a variable minimal length in the spacetime. Finally, we investigate the effects of GUP on the stability of circular orbits

hep-th↗