Miracle-dz/UniFAR-FTUs huggingface dataset:
A Note on Fractal Channel Networks

This paper studies the relation between the structure of river networks and the features of their geomorphologic hydrologic response. A mathematical formulation of connectivity of a drainage network is proposed to relate contributing areas and the network geometry. In view of the connectivity conjecture, Horton's bifurcation ratio R(B) tends, for high values of Strahler's order OMEGA of the basin, to the area ratio R(A), and Horton's length ratio R(L) equals, in the limit, the single-order contributing area ratio R(a). The relevance of these arguments is examined by reference to data from real basins. Well-known empirical results from the geomorphological literature (Melton's law, Hack's relation, Moon's conjecture) are viewed as a consequence of connectivity. It is found that in Hortonian networks the time evolution of contributing areas exhibits a multifractal behavior generated by a multiplicative process of parameter 1/R(B). The application of the method of the most probable distribution in view of connectivity contributes new inroads toward a general formulation of the geomorphologic unit hydrograph, in particular generalizing its width function formulation. A quantitative example of multifractal hydrologic response of idealized networks based on Peano's construct (for which R(B) = R(A) = 4, R(L) = 2) closes the paper.
Effects of soiling on PV module and radiometer performance

The question of "how much does the output of PV modules and radiometers decrease due to soiling? " is often asked, but data are rarely available to answer the question. Related questions are: a) how effectively does rain clean soiled devices; and b) how often should radiometers and modules be cleaned? Answers to these questions are essential to predict PV module performance or the accuracy (uncertainty) of PV module performance data. Results of module and radiometer soiling data from three independent applications are presented in this paper. Data cover soiling periods from 16 months to five years, and results are consistent for all three applications.
Soft Robotic Fingertips

Part I of this article showed that making robotic fingers from soft materials helps them cope with the following three prob lems. First, the impact forces that occur at the instant of grasping are reduced. Second, commonly used objects with uneven surfaces can be grasped comfortably due to the confor mal nature of the soft fingers. Third, the repeated strains that are induced during manipulations are dissipated. The problem to solve now is that of modeling and controlling the overall impedance of a soft finger or of a finger that has a soft tip. This is the issue addressed in this part. This part presents the experimental determination of the pas sive impedance parameters of a soft (gel-filled) fingertip and formulates an approach to account for the soft fingertip model when controlling the overall impedance of a finger that carries the soft tip. The approach is demonstrated via four experi ments, each with a unique goal. Also showed experimentally is how the presence of passive damping helps reduce the peak impact forces that occur as a rigid object is grasped by the fingers of a robotic hand.
Limitations on the measurement of relaxation times using a pulsed Kerr effect method

Relaxation times may be measured by observation of the birefringence produced by the application of a pulsed electric field. A brief resume is given of the methods of detection of the birefringence. These may be linear or quadratic according to whether the signal is proportional to the first or second power of the birefringence. A combination (quasi-linear) is also possible. Considerations of signal-to-noise ratio, current limitations of the detector system and signal distortion are fully treated. The analysis when two relaxation times are present simultaneously is given and it is shown that such a case may be confused with the results obtained with one relaxation time if the parameters are not fully known. Errors in the determination of relaxation times are examined. It is concluded that a linear detection method is preferable to a quadratic one because the signal-to-noise ratio and distortion tends to be less but these advantages do not occur when large bandwidths have to be used.
Time-stretch microscopy based on time-wavelength sequence reconstruction from wideband incoherent source

Time-stretch microscopy has emerged as an ultrafast optical imaging concept offering the unprecedented combination of the imaging speed and sensitivity. However, dedicated wideband and coherence optical pulse source with high shot-to-shot stability has been mandated for time-wavelength mapping—the enabling process for ultrahigh speed wavelength-encoded image retrieval. From the practical point of view, exploiting methods to relax the stringent requirements (e.g., temporal stability and coherence) for the source of time-stretch microscopy is thus of great value. In this paper, we demonstrated time-stretch microscopy by reconstructing the time-wavelength mapping sequence from a wideband incoherent source. Utilizing the time-lens focusing mechanism mediated by a narrow-band pulse source, this approach allows generation of a wideband incoherent source, with the spectral efficiency enhanced by a factor of 18. As a proof-of-principle demonstration, time-stretch imaging with the scan rate as high as MHz and diffraction-limited resolution is achieved based on the wideband incoherent source. We note that the concept of time-wavelength sequence reconstruction from wideband incoherent source can also be generalized to any high-speed optical real-time measurements, where wavelength is acted as the information carrier.
Statistical Mechanics of a Multipolar Gas: A Lattice Field Theory Approach

A recently proposed lattice field theory approach to the statistical mechanics of a classical Coulomb gas (J. Chem. Phys. 1992, 97, 5653) is generalized to treat particles with arbitrary electric multipole moments. Explicit development of the mean-field approximation is given for the case of mobile dipoles and monopoles (ions) surrounding an arbitrary collection of fixed charges embedded in macroions. In particular, a modified Poisson−Boltzmann (PB) equation is derived in which the mobile dipoles provide an effective spatially dependent dielectric constant. This equation implies a self-consistent iteration procedure by which the monopole and dipole densities are simultaneously determined in terms of single scalar (PB) field. Moreover, this equation can be derived from a minimum principle; an annealing strategy for computing the PB field is thereby suggested. In addition, explicit mean-field expressions for thermodynamic free energies are obtained as simple functionals of the PB field. Connection to the we.
Large-scale galaxy distribution in the Las Campanas Redshift Survey

We make use of three-dimensional clustering analysis, inertia tensor methods, and the minimal spanning tree technique to estimate some physical and statistical characteristics of the large-scale galaxy distribution and, in particular, of the sample of overdense regions seen in the Las Campanas Redshift Survey (LCRS). Our investigation provides additional evidence for a network of structures found in our core sampling analysis of the LCRS: a system of rich sheet-like structures, which in turn surround large underdense regions criss-crossed by a variety of filamentary structures. We find that the overdense regions contain ∼40–50 per cent of LCRS galaxies and have proper sizes similar to those of nearby superclusters. The formation of such structures can be roughly described as a non-linear compression of protowalls of typical cross-sectional size ∼20–25 h−1 Mpc; this scale is ∼5 times the conventional value for the onset of non-linear clustering – to wit, r0, the autocorrelation length for galaxies. The comparison with available simulations and theoretical estimates shows that the formation of structure elements with parameters similar to those observed is presently possible only in low-density cosmological models, Ωmh∼0.2–0.3, with a suitable large-scale bias between galaxies and dark matter.
An indirect adaptive controller with a self-excitation capability

An indirect adaptive pole placement controller is presented which stabilizes and asymptotically regulates any discrete-time single-input, single-output linear time-invariant plant which is of known order n, is controllable, and observable, and has unknown parameters. To avoid singular points in the algorithm, the adaptive controller solves the pole-placement design equation asymptotically with time rather than trying to solve it exactly at each time instant. The stability of the adaptive control system and the asymptotic regulation of the plant output to zero are ensured by an additional self-excitation generated by the adaptive controller. A novel kind of an error signal to control the magnitude of the self-excitation is obtained by suitably filtering the self-exciting signal and monitoring changes of the controller parameters as they are generated by the adaptive algorithm. >
Block Diagrams and the Extension of Timelike Two‐Surfaces

The work of Finkelstein, Kruskal, Graves and Brill, Carter, and Boyer and Lindquist on the extension and schematic representation of 2‐dimensional metrics is systematized and generalized. As a result, a number of extensions may be found by inspection. Some well‐known examples are given, and the technique is applied to the ``soluzioni oblique'' of Levi‐Civita.
Microcantilever chaotic motion suppression in tapping mode atomic force microscope

The tapping mode is one of the mostly employed techniques in atomic force microscopy due to its accurate imaging quality for a wide variety of surfaces. However, chaotic microcantilever motion impairs the obtention of accurate images from the sample surfaces. In order to investigate the problem the tapping mode atomic force microscope is modeled and chaotic motion is identified for a wide range of the parameter's values. Additionally, attempting to prevent the chaotic motion, two control techniques are implemented: the optimal linear feedback control and the time-delayed feedback control. The simulation results show the feasibility of the techniques for chaos control in the atomic force microscopy.
Computational turbulent stress closure for large-eddy simulation of compressible flow

Abstract Large-eddy simulation (LES) focuses on the primary features of a turbulent flow with length scales larger than an externally specified filter width Δ. Scales smaller than Δ are removed from the simulation by spatial filtering which allows the use of a grid spacing h on the order of Δ. In most LES, the subgrid resolution r = Δ/h is rather coarse (r≈ 1–2) and an additional filtering is induced by the spatial discretization method. This modifies the dynamics of the smaller resolved scales. The computational turbulent stress tensor ξ ij expresses this modification and incorporates the regular turbulent stress as well as numerical high-pass filter contributions. We consider the computational turbulent stress for three-dimensional compressible flow. Compressibility motivates a decomposition of ξ ij in a part that is primarily associated with velocity variations and a part associated with density variations. The density variations depend strongly on the Mach number while the velocity variations remain much closer to their incompressible level, even in low supersonic flow. An a priori investigation of a turbulent mixing layer quantifies the significance of the density variations at sufficiently high Mach number with a magnitude of up to 20% of ξ ij . An explicit modelling of density variations in terms of approximate deconvolution is proposed and shown to accurately follow the Mach number dependence.
Dose calculations at high altitudes and in deep space with GEANT4 using BIC and JQMD models for nucleus–nucleus reactions

Radiation exposure of aircrew is more and more recognized as an occupational hazard. The ionizing environment at standard commercial aircraft flight altitudes consists mainly of secondary particles, of which the neutrons give a major contribution to the dose equivalent. Accurate estimations of neutron spectra in the atmosphere are therefore essential for correct calculations of aircrew doses. Energetic solar particle events (SPE) could also lead to significantly increased dose rates, especially at routes close to the North Pole, e.g. for flights between Europe and USA. It is also well known that the radiation environment encountered by personnel aboard low Earth orbit (LEO) spacecraft or aboard a spacecraft traveling outside the Earth's protective magnetosphere is much harsher compared with that within the atmosphere since the personnel are exposed to radiation from both galactic cosmic rays (GCR) and SPE. The relative contribution to the dose from GCR when traveling outside the Earth's magnetosphere, e.g. to the Moon or Mars, is even greater, and reliable and accurate particle and heavy ion transport codes are essential to calculate the radiation risks for both aircrew and personnel on spacecraft. We have therefore performed calculations of neutron distributions in the atmosphere, total dose equivalents, and quality factors at different depths in a water sphere in an imaginary spacecraft during solar minimum in a geosynchronous orbit. The calculations were performed with the GEANT4 Monte Carlo (MC) code using both the binary cascade (BIC) model, which is part of the standard GEANT4 package, and the JQMD model, which is used in the particle and heavy ion transport code PHITS GEANT4.
MINIMAX ENTROPY SOLUTIONS OF ILL-POSED PROBLEMS

Convergent methodology for ill-posed problems is typically equivalent to application of an operator dependent on a single parameter derived from the noise level and the data (a regularization parameter or terminal iteration number). In the context of a given problem discretized for purposes of numerical analysis, these methods can be viewed as resulting from imposed prior constraints bearing the same amount of information content. We identify a new convergent method for the treatment of certain multivariate ill-posed problems, which imposes constraints of a much lower information content (i.e., having much lower bias), based on the operator’s dependence on many data-derived parameters. The associated marked performance improvements that are possible are illustrated with solution estimates for a Lyapunov equation structured by an ill-conditioned matrix. The methodology can be understood in terms of a Minimax Entropy Principle, which emerges from the Maximum Entropy Principle in some multivariate settings.
Statistics of intense dawn‐dusk currents in the Earth's magnetotail

We consider Cluster observations of events with an intense current density (>5 nA/m2) in the magnetotail current sheet. We use measurements by Cluster mission in the central magnetotail (X <− 16 RE, |Y|<10 RE, and |Bx|<10 nT) in the 2003 season when the spacecraft separation was about ∼300 km. For this season, when Cluster can probe very small scale currents, we collect the statistics of observations of strong current densities jy (in GSM coordinate system) and compare curlometer data with plasma parameters. The most intense currents are observed under disturbed conditions (plasma flow vx>300 km/s). We introduce the parameter vD/vTi (where vD=jy/ene, ne is an electron density, and vTi is a proton thermal velocity) and show that cases with vD/vTi∼1 correspond to the most intense currents observed in the vicinity of the reconnection regions. The comparison of electron and proton velocities demonstrates that electron often carry almost the entire current measured by a curlometer technique. The strong electron temperature anisotropy Te∥/Te⊥>1.2 corresponds to large magnitudes of By component of the magnetic field. We conclude that intense current sheets are often characterized by significant (more than 30%) contribution of electron curvature currents to the cross‐tail current. The comparison of observations and models shows that the electron anisotropy level is likely controlled by competition of two processes: the electron scattering on fluctuations generated by fire‐hose instability and the acceleration in sheared magnetic field configurations. We also suggest that current sheets embedded into the strong plasma flows (vx/vTi>0.1) can be balanced by ion flow anisotropy.
Investigation of inter-molecular hydrogen bonding in the binary mixture (acetone + water) by concentration dependent Raman study and ab initio calculations

This paper reports that vibrational spectroscopic analysis on hydrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water complexes with changing water concentrations. The optimised geometries and wavenumbers of the neat acetone molecule and its complexes are calculated by using ab initio method at the MP2 level with 6–311+G(d,p) basis set. Changes in wavenumber position and linewidth (fullwidth at half maximum) have been explained for neat as well as binary mixtures with different mole fractions of the reference system, acetone, in terms of intermolecular hydrogen bonding. The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the concentration dependent changes in the spectral features in terms of hydrogen bonding.
Exact calculations of discrete-time process noise statistics for hybrid continuous/discrete time applications

Discrete-time models of continuous-time plants are commonly required due to the popular use of computers to implement control and estimation algorithms. When stochastic design techniques are utilized, it is necessary to determine the equivalent discrete-time process noise statistics from the continuous-time process noise statistics. Several references on the object of discrete-time control and estimation present approximate solutions for the necessary transformation; in this paper exact solutions are discussed. <<ETX>>
Acquisition of Point Cloud Data in 3D Reconstruction

This paper takes the following measures to solve the problem of 3D reconstruction. Camera calibration is based on chessboard, taking several different attitude images. Use corner point coordinates by corner detection to process camera calibration. The calibration result is important to be used to correct the distorted image. Next, the left and right images should be matched to find out the object surface points’ imaging position respectively so that the object depth can be calculated by triangulation. According to the inverse process of projection mapping, we can project the object depth and disparity information into 3D space. As a result, we can obtain dense point cloud, which is ready for 3D reconstruction.
The Multivariate Analysis of Qualitative Data: Interactions among Multiple Classifications

Abstract For the m-way contingency table, we discuss both the direct estimation of the multiplicative interactions among the m variables, and the indirect testing of hypotheses pertaining to these interactions. We consider, among other things, hierarchical hypotheses pertaining to the interactions among the m variables, including hypotheses that can be expressed in terms of one or more of the following kinds of concepts: (a) the usual concepts of independence and equiprobability; (b) concepts describing conditional properties (e.g., conditional independence) pertaining to a subset of the m variables, given the level of some of the remaining variables; (c) concepts related to the usual logit-analysis or to a generalized form of logit-analysis; and (d) concepts related to a more general log-linear model. Methods of partitioning these hypotheses are introduced which provide, among other things, insight into the relationship between tests applied to the m-way table and tests applied to marginal tables formed .
Monaural and Binaural Discrimination against Competing Sentences

PB‐50 lists were presented in a sound field against a background of spoken sentences. Four signal‐to‐noise ratios plus one quiet condition were used. Test items came from a loudspeaker to one side of the subject and competing sentences from a second loudspeaker, on the opposite side. Sixteen normal hearers underwent both test and retest under one binaural and two monaural conditions. Discrimination functions for these conditions showed similar configurations, but were displaced from one another along the signal‐to‐noise axis. Head‐shadow effects caused poorer discrimination during monaural listening when test items come from the far side of the head. Monaural efficiency with the open ear facing the source of test items was almost as good as binaural efficiency. However, binaural performance here exhibited an advantage equal to approximately a 3‐dB shift in signal‐to‐noise ratio, despite the fact that the head‐shadow effect enhanced interference in the far ear by almost 13 dB. [Work supported by the Vetera.
Active and Passive Suppressions of Nonlinear Panel Flutter Using Finite Element Method

Active and passive suppression schemes for nonlinear flutter of composite panel are investigated using lead zirconate titanate (PZT). First, in the active control method, the optimal controller based on the linear optimal control theory is designed for flutter suppression of the panel. Second, a new approach, a passive suppression scheme, is suggested for suppression of the nonlinear panel flutter. A passive damping technology, using one shunt circuit and two independent shunt circuits, which is believed to be a more robust suppression system in practical operation, is proposed. This approach requires very little or no electrical power. In this passive method, the piezoelectric shunt circuit, which consists of resistor-inductor-capacitor elements in series, is applied. In both methods, a finite element formulation for composite plates with PZT layers is derived using classical laminated plate theory. The adopted aerodynamic theory is based on the quasi-steady piston theory, and the von Karman nonlinear strain-displacement relation is used. A modal reduction technique is used to reduce the number of modes involved and to simplify the nonlinearity of the model. Numerical results, which are based on the reduced nonlinear modal equations of active and passive suppression for nonlinear panel flutter are presented in the time domain using the Newmark-β method. To achieve the best suppression effect, optimal shape and location of the piezoceramic (PZT) patches are determined by using genetic algorithms. The results clearly demonstrate that the passive damping scheme as well as active control can effectively attenuate the flutter.
Regulatory mechanisms of microRNAs in endocrine disorders and their therapeutic potential

MicroRNAs (miRNAs) are small endogenous non-coding RNA molecules capable of regulating gene expression at the post-transcriptional level either by translational inhibition or mRNA degradation and have recently been importantly related to the diagnosis and prognosis of the most relevant endocrine disorders. The endocrine system comprises various highly vascularized ductless organs regulating metabolism, growth and development, and sexual function. Endocrine disorders constitute the fifth principal cause of death worldwide, and they are considered a significant public health problem due to their long-term effects and negative impact on the patient’s quality of life. Over the last few years, miRNAs have been discovered to regulate various biological processes associated with endocrine disorders, which could be advantageous in developing new diagnostic and therapeutic tools. The present review aims to provide an overview of the most recent and significant information regarding the regulatory mechanism of miRNAs during the development of the most relevant endocrine disorders, including diabetes mellitus, thyroid diseases, osteoporosis, pituitary tumors, Cushing’s syndrome, adrenal insufficiency and multiple endocrine neoplasia, and their potential implications as disease biomarkers.