Miracle-dz/UniFAR-FTUs huggingface dataset:
Graphs and matroids determined by their Tutte polynomials

Acknowledgements First and foremost, I thank Marc Noy for his guidance throughout these years and for his advice on all aspects of mathematical life. He has been a constant source of ideas and problems, as well as support and encouragement, and from him I have learnt a wealth of beautiful and fascinating mathematics. I have always felt inclined towards combinatorics, but I am sure I would not have enjoyed it as much if I had not encountered Marc's contagious enthusiasm. During these years I have had the pleasure of meeting many people that have helped me both scientifically and personally. I would like to thank especially Joe Bonin for his hospitality during my visits to The George Washington University. Through his geometric approach I have learnt almost all the matroid theory I know, and I certainly cannot imagine a better teacher. I heartfully appreciate all the time he has generously spent working with me and solving my doubts, and I feel lucky to have him as a friend. I am also very grateful to Criel Merino, Alberto Márquez, and Pastora Revuelta for many fruitful discussions and for their pleasant company in several occasions. Voldria aprofitar l'ocasió per agrair el suport no matemàtic (però no per això menys important) que he rebut de tots amb els qui comparteixo el dia a dia. Primer de tot, als meus pares i al meu germà Jordi per estar sempre al meu costat. A tots els que aconsegueixen que els lligams no es trenquin (malgrat que l'expansió de l'univers tendeixi a dispersar-nos): Maite, Guille, Maria, Julio, Raimon. A la Montse per molts consells i pel suport a la realització física d'aquesta tesi. I als companys del departament de Matemàtica Aplicada II, en especial al " grup SEU " , per contribuir a que treballar sigui més que tancar-se en un despatx.
Relativistic Runaway Electron Avalanches Inside the High Field Regions of Thunderclouds

Relativistic Runaway Electron Avalanches Inside the High Field Regions of Thunderclouds by Eric Scott Cramer Dissertation Advisor: Hamid K. Rassoul, Ph.D. In this dissertation, simplified equations describing the transport and energy spectrum of runaway electrons are derived from the basic kinematics of the continuity equations. These equations are useful in modeling the energy distribution of energetic electrons in strong electric fields, such as those found inside thunderstorms. Dwyer and Babich [2011] investigated the generation of low-energy electrons in relativistic runaway electron avalanches. The paper also developed simple analytical expressions to describe the detailed physics of Monte Carlo simulations of relativistic runaway electrons in air. In this work, the energy spectra of the runaway electron population are studied in detail. Dependence of electron avalanche development on properties such as the avalanche length, radiation length, and the effective Møller scattering efficiency factor, are discussed in detail. To describe the shapes of the electron energy spectra for a wide range of electric field strengths, the random deviation of electron energy loss from the mean value is added to the solutions. We find that this effect helps maintain an exponential energy spectrum for electric fields that approach the runaway electron threshold field. We also investigate the source mechanisms of Terrestrial Gamma-ray Flashes, which are a result of relativistic runaway electron avalanches in air. In this study, the bremsstrahlung photons are propagated through the atmosphere, where they undergo Compton scattering, pair production, and photoelectric absorption. We model these interactions with a Monte Carlo simulation from the TGF source location (assumed to vary between 8 and 20 km) and the edge of the atmosphere (≈ 100 km). We then propagate these photons to a satellite plane at 568 km in order to compare with measurements. In collaboration with the GBM instrument team in Huntsville, AL, we were able to model spectral and temporal properties of observed TGFs. Although the analysis of individual TGF photon spectra was qualitative, we were able to put some constraints, i.e. source altitude and beaming angle, on a sample of observed GBM TGFs. However, assuming a height of 15 km, we were able to model the softening in the spectrum observed as the satellite moves off-axis from the TGF source location [Fitzpatrick et al., 2014]. The conclusion of this analysis shows that Compton scattering alone can not explain the temporal dispersion observed. This suggests that an intrinsic time variation exists at the source of the TGF.
Three-Dimensional Static and Free Vibration Analysis of Carbon Nano Tube Reinforced Composite Cylindrical Shell Using Differential Quadrature Method

In this paper, bending and free vibration analysis of carbon nanotubes reinforced composite (CNTRC) cylindrical shell is carried out using the three-dimensional theory of elasticity. The single-walled carbon nanotubes (SWCNT) reinforcement is either uniformly distributed (UD) or functionally graded (FG) in the thickness direction which, are specified as the cases FG − Δ, FG −∇, FG −♢ and FG-X. Effective material properties of CNTRC cylindrical shell are estimated according to the rule of mixture as well as considering the CNT efficiency parameters. An analytical solution is performed by using Fourier series along the axial coordinate together with state space technique along the radial coordinate for the simply supported CNTRC cylindrical shell. Moreover, for CNTRC cylindrical shell with other edges boundary conditions, a semi-analytical solution is accomplished by using differential quadrature method (DQM) along the axial coordinate and state space technique along the radial coordinate. Present approach .
Influence of Rootstocks (Gisela 5, Gisela 6, MaxMa, SL 64) on Performance of ‘0900 Ziraat’ Sweet Cherry

This study was carried out in order to determine the effect of rootstocks (Gisela 5, Gisela 6, MaxMa 14 and SL 64) on performance of sweet cherry cultivar â€˜0 900 Ziraatâ€™ during 2010-2013 years. The trail in randomized block design was established as to factorial design. Each graft combination included 20 trees. The trees was trained as Spanish Bush training system. At the end of study, effect of rootstocks on vegetative growth was found significant. It has been determined that the trees grafted on SL 64 and MaxMa 14 rootstocks were more vigorous than the those grafted on Gisela 5 and Gisela 6. The rootstocks formed significant differences at the precocity. While the first blooming on the trees grafted on Gisela 5 and Gisela 6 rootstocks occurred at the second year after planting, the first blooming on the trees on MaxMa 14 and SL 64 rootstocks occurred at fourth year after planting. It has been determined that occur significant differences on yield per tree and yield efficiency among rootstocks. In terms of yield per tree and yield efficiency, While the lowest value was in SL 64 rootstock, the highest value was recorded in Gisela 5, and it has been determined that the differences between three rootstocks (Gisela 5, Gisela 6 and MaxMa 14) were not significant. While fruits weight varied according to the rootstock used in study, the trees grafted on Gisela 5 had the smallest fruit. Accompanied with differences between MaxMa 14 and SL 64 rootstocks were not significant, the biggest fruits were produced on trees grafted on SL 64 rootstock. As a result of the statistical analysis, it has determined that the rootstocks that used in trial did not create significant differences on soluble solids content (SSC) value. One of the most significant diagnosis was 6 % mortality rate that occurred on trees grafted Gisela 5 and Gisela 6 rootstocks.
Bounds on the expected waiting time in a GI/G/1 queue: upgrading for low traffic intensity

For a GI/G/1 queue we derive new lower and uper bounds on the expected stationary waiting time which are a function of more than the first two moments of the inter-arrival and service times. When the probability for a delay is low, the bounds tend to be better than other bounds. This is illustrated in an example of a Uniform/Uniform/1 queue.
Advances in the Theory of A, B, C Numbers and Its Application to Waveguide Propagation

k;n in x (n = 1;2;3;:::) of the Kummer con∞uent hypergeometric function '(a;c;x), (a = c=2 i jk | complex, c = 3, x = jz, k, z | real, i1 0), on the real positive parameters jfij and „0 (0 ‡ (c) 0;n=2), satisfying certain criterion, is analyzed numerically, stipulating that n = 1 and „ r0 ‚ 10. The outcomes are pictured in a graphical form. A second limit of the domain of existence of A1, B1 and C1 in the jfij i A1- and „0 i A1-, jfij i B1- and „0 i B1-, and jfij i C1- and „0 i C1-planes, resp. is specifled, linked with a representative of the L1(c;n) numbers, akin to the zeros ‡ (c) k;n for k ! i1, in addition to the previously found flrst one, related to ‡ (c) 0;n =2. It is established also that as for ‡ (c) 0;n =2 < „
Reconstruction of B hadron decays at DELPHI

This thesis describes three analyses related to heavy quarks. The analysis with the largest impact is the extraction of parameters of heavy quark decays using the lepton energy spectrum and the hadronic mass spectrum in semileptonic B decays. The extraction of the parameters allows to test the framework used to theoretically describe the decay of heavy mesons, and more accurate knowledge of the parameter values results in greater accuracy in the determination of the element |Vcb| of the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix. The determination described in this thesis is important, since it is so far the only one where the full lepton energy spectrum has been used. The other determinations are based on using only a part of the spectrum. The first extraction of the parameters in the kinetic mass scheme was based on the statistical moments of the lepton energy spectrum and hadronic mass spectrum measured using the data collected at delphi. In the second analysis, the angular distribution of fragmentation particles in Z → bb̄ and Z → cc̄ events was studied using the delphi data. The analysis gave the first direct experimental evidence of the dead cone effect, or the depletion of fragmentation particles at small emission angles, predicted by perturbative quantum chromodynamics. The third analysis is a simulation study of top quark pair production at a possible future ee linear collider with a 3 TeV center-of-mass energy. The study allowed to estimate the accuracies with which the cross-section and forward-backward asymmetry could be measured.
Multiplicative watermarking algorithm based on wavelet visual model

The additive watermarking algorithm has good imperceptibility,however,the robustness of watermark is poor.As a result,a multiplicative image watermarking method was proposed by combining the visual model in the wavelet domain.In the proposed embedding scheme,the middle-frequency subband acted as the watermark embedding space,which was used to achieve the tradeoff between the imperceptibility and the robustness of watermarking system.Besides,the embedding strength factor was determined by considering the frequency masking,luminance masking and texture masking of host image.In the proposed detection scheme,the probability density function of wavelet coefficients was modeled by the Generalized Gaussian Distribution(GGD),and the watermark decision threshold was obtained by using the Neyman-Pearson(NP) criterion,and the Receiver Operating Characteristic(ROC) curve between the probability of false alarm and the probability of detection was derived.Finally,the robustness of the proposed watermarking was tested when being against common image processing attacks such as JPEG compression,Additive White Gaussian Noise(AWGN),scaling and cropping.The experimental results demonstrate that the proposed method has good detection performance and good robustness.
A Behavioral Theory of the Firm

Provides a theory of decision making within business organizations. Contrary to the economic theory of the firm, which sees firms as profit-maximizing entities, the authors advocate a theory based on empirical observation of actual firm decision-making. Various features of firm decision-making are identified. First, firms are coalitions of participants whose individual goals may and often do conflict. How this conflict is resolved is determined by the firm's bargaining process. This process is constrained by past behavior and decisions. Second, the authors reject the notion that firms are one-dimensional profit-maximizers in favor of a view of firms as entities with many different objectives that will accept suboptimal outcomes if they are above a minimum level. Congruent with this, a firm's search activity occurs in response to a perceived problem and is limited in scope. The effect is that firm policies will change only incrementally. Also impeding radical policy change is the fact that firms react to uncertainty using standardized decision rules. Using this theory, two computer models of business decision-making are presented and compared with actual results. These models are shown to have especially good predictive power. (CAR)
Classifying Human Left and Right Hand Motor Imagery from EEG Rhythm Using Hurst Exponent

This study researches whether human intentions of left and right hands motor imagery can be decoded by Hurst exponent in non-invasive EEG. Twenty five healthy subjects participated in the experiment. Through the analysis of EEG rhythms, we found that the Hurst exponent of right hand motor imagery is larger than that left in most of male right hemisphere brain electrodes, especially C4, P4 and T6. Secondly, the value of Hurst exponent indicates that EEG rhythm has a long memory and persistence. Besides, through Single-factor variance analysis, we can choose the more effective electrode for feature classification. K nearest neighbor discriminator analysis is utilized to dynamically classify left and right hand motor imagery according to Hurst exponent features. As a result, we gained a male average maximum classification accuracy of 76.82%. Lastly, we discussed the influence of different time length on the classification accuracy.
Full-waveform inversion of cycle-skipped seismic data by frequency down-shifting

Summary Full-waveform inversion can be severely compromised by problems of cycle skipping; this occurs when predicted and observed data differ by more than half a cycle, and it leads the inversion to recover a local rather than the global minimum model. Overcoming cycle skipping normally requires both a good starting model and low-frequency content in the field data. Here we present a scheme that uses a non-linear extrapolation to add missing low- frequencies into the field data. We demonstrate the scheme using a 3D OBC field dataset, and show that it can invert to recover the global minimum model even when the original un-extrapolated field dataset is significantly cycle skipped. Introduction Full-waveform inversion (FWI) is an optimization scheme that seeks to find the global minimum of the misfit between field seismic data and synthetic data generated by a model. It proceeds towards the global minimum by a series of local linearized iterations from a starting model. The true relationship between model and data however is non-linear, and several of these non-linearities can lead the inversion scheme to become trapped within local minima rather than reaching the desired global solution. Amongst these non-linearities, the most important is that produced by the oscillatory nature of the seismic data themselves. A cycle-skipped starting model, that is one that produces data that differ by more than half a cycle with respect to the field data, will normally lead the inversion in entirely the wrong direction towards a local minimum. This problem is well known; its practical solution typically requires a highly accurate starting model combined with low-frequency field data. In these circumstances, the predicted starting data are not cycle skipped at the lowest frequencies, and the global solution can be found by starting FWI using the lowest frequencies in the field data. In this paper, we present a FWI scheme that relaxes the requirement for low-frequency field data and a good starting model, and that is able to reach the global minimum solution even when the starting data are cycle skipped. We do this by using the observed field data to synthesize low-frequency data that were not present in the original field data. We then invert these invented low- frequencies, which has the effect of dragging the starting model towards the global minimum. We then switch to invert the true field data which are now no longer cycle skipped, and so reach the global minimum.
Modeling human performance on the traveling salesman problem: empirical studies and computational simulations

The traveling salesperson problem (TSP) consists of attempting to find the shortest complete tour through a series of points (cities), starting and ending with the same point. This problem is a member of the set of computationally hard, or NP complete, problems, for which the best known solutions are obtained in exponential time relative to the problem size. Human solutions, however, are known to be both rapid and of high quality. This thesis attempts to determine the processes used by humans in solving these problems and encode them in the form of a running computer program. For this purpose, TSP problem presentation software was developed to present problems and collect data at a finer grain scale than is possible with previous paper-and-pencil versions of the task. Data recording included real-time recording of mouse position at a 100Hz sampling rate. This software was used to conduct a set of six experiments. Experiment 1 validated the computer interface using a problem set from a previous TSP study (MacGregor and Ormerod, 1996). Experiment 2 employed a data set consisting of random problems matched on size to the problems employed in Experiment 1. Experiment 3 constrained the start of the problem solving episode by fixing a starting point. Experiment 4 introduced larger randomly constructed problems. Experiment 5 employed shaped problems intended to explore problem complexity due to contours. Experiment 6 employed an obscured interface that presented high-frequency spatial information only in the area immediately under the computer mouse, blurring distant areas. The experiments conducted provide a number of findings. Problem solution times are linearly proportional to the number of problem points, with individual moves taking ∼1 second. Solution accuracy is generally within ∼5% of optimal path length for the majority of solvers and problems. Accuracy is lower on more complex problems where complexity is determined by factors including the number of points in a problem, problem shape, and the number of interior (non-convex hull) points. Problem solving is preceded by 2-3 seconds during which the problem is scanned and a rough solution is developed. Experiment 6 demonstrated that planning requires only low-frequency spatial information provided by a blurred display. The pattern of mouse movement was similar in this condition to the normal interface experiments. This pattern involved initial travel that was indirect, consisting of multiple exploratory movements. Beyond the first two moves, mouse movements become more direct and there is a reduction of distance traveled and time and strokes taken. Evidence for learning is minimal indicating that the strategies and processes used by human solvers are innate or well-practiced, and therefore general (e.g., perceptually based, weak methods, etc.). These empirical findings guided the construction of a TSP solving algorithm designated the GL-TSP, that combines global perceptual processing and local serial problem solving. (Abstract shortened by UMI.)
A singularly perturbed age structured SIRS model with fast recovery

Age structure of a population often plays a significant role in the spreading of a disease among its members. For instance, childhood diseases mostly affect the juvenile part of the population, while sexually transmitted diseases spread mostly among the adults. Thus, it is important to build epidemiological models which incorporate the demography of the affected populations. Doing this we must be careful as many diseases act on a time scale different from that of the vital processes. For many diseases, e.g. measles, influenza, the typical time unit is one day or one week, whereas the proper time unit for the vital processes is the average lifespan in the population; that is, 10-100 years. In such a case, the epidemiological model with vital dynamics becomes a multiple time scale model and thus it often can be significantly simplified by various asymptotic methods. The presented paper is concerned with an SIRS type disease spreading in a population with a continuous age structure modelled by the McKendrick-von Foerster equation. We consider a disease with a quick recovery rate in a large population. Though it is not too surprising that in such a model the introduced disease quickly vanishes, the result is mathematically interesting as the error estimates are uniform on the whole infinite time interval, in contrast to the typical results based on the Tikhonov theorem and classical asymptotic expansions.
Circumferential SH wave in orthotropic hollow cylinders

Based on linear three-dimensional elasticity theory,the displacements expressed circumferential wave controlling equation of orthotropic hollow cylinder is obtained.The axial displacement is independent of the other two directions.And the waves can be decomposed into SH wave and Lamb-like wave.Through the Bessel functions,the dispersion equation of circumferential SH wave is obtained.There are two elastic constant determining the SH wave characteristics,one controlling the wave frequency and the other controlling the wave velocity.Finally,The influences of the two constants and the wave number on the SH wave displacement mode shapes are discussed.
Structural Vibration Signal Denoising Using Stacking Ensemble of Hybrid CNN-RNN

Vibration signals have been increasingly utilized in various engineering fields for analysis and monitoring purposes, including structural health monitoring, fault diagnosis and damage detection, where vibration signals can provide valuable information about the condition and integrity of structures. In recent years, there has been a growing trend towards the use of vibration signals in the field of bioengineering. Activity-induced structural vibrations, particularly footstep-induced signals, are useful for analyzing the movement of biological systems such as the human body and animals, providing valuable information regarding an individual’s gait, body mass, and posture, making them an attractive tool for health monitoring, security, and human-computer interaction. However, the presence of various types of noise can compromise the accuracy of footstep-induced signal analysis. In this paper, we propose a novel ensemble model that leverages both the ensemble of multiple signals and of recurrent and convolutional neural network predictions. The proposed model consists of three stages: preprocessing, hybrid modeling, and ensemble. In the preprocessing stage, features are extracted using the Fast Fourier Transform and wavelet transform to capture the underlying physics-governed dynamics of the system and extract spatial and temporal features. In the hybrid modeling stage, a bi-directional LSTM is used to denoise the noisy signal concatenated with FFT results, and a CNN is used to obtain a condensed feature representation of the signal. In the ensemble stage, three layers of a fully-connected neural network are used to produce the final denoised signal. The proposed model addresses the challenges associated with structural vibration signals, which outperforms the prevailing algorithms for a wide range of noise levels, evaluated using PSNR, SNR, and WMAPE.