Miracle-dz/UniFAR-FTUs huggingface dataset:
A Necessary Condition for the Existence of Disjoint Bases of a Family of Infinite Matroids

Let M = (Mr)r2R be a system of matroids on a set S. Following the ideas of Nash-Williams (7), for every transfinite sequence f of distinct elements of S, we define a number (f). We prove that the condition that (f) 0 for every possible choice of f is necessary for M to have a system of mutually disjoint bases. Further, we show that this condition is sucient if R is countable and Mr is a rank-finite transversal matroid for every r 2 R. We also present conjectures about edge-disjoint spanning trees and detachments of countable graphs.
Optimal precoding for transmissions over linear time-varying channels

We derive an approximate analytic model for the eigenfunctions of underspread LTV channels which plays a fundamental role in the analysis/synthesis of the optimal precoding that maximizes the information rate in transmissions over linear time-varying (LTV) channels. We assume that channel status information is available to both receiver and transmitter and that the channel impulse response can be predicted exactly, within a finite duration interval, from its past evolution. More specifically, we use our analytic model to prove that the optimal precoding is equivalent to applying the water-filling principle in the time-frequency domain and to simplify the computation of the optimal precoder. We include numerical results to support the validity of our model.
Performance analysis of signed self-orthogonalizing adaptive lattice filter

This paper describes the novel signed self-orthogonalizing adaptive lattice filter (SSALF) structure to enhance the slow convergence rate caused by an eigenvalue disparity whilst constraining the level of the convergence rate and the misadjustment required by a specification. The SSALF structure is also implemented by the partial lattice predictor in order to reduce a computational complexity. The performance analysis based on the convergence model of the lattice predictor is given in terms of the mean-squared error and the variance of the reflection coefficient error. Computer simulations are undertaken to verify the performance and the applicability of the proposed filter structure.
Positive root vectors

As a generalisation of the well-known result of Perron and Frobenius, it was shown by Rothblum [13] and independently by Richman and Schneider [12] that every nonzero matrix with non-negative entries has a basis of the root space corresponding to the maximal eigenvalue, represented by root vectors with non-negative entries. Krein and Rutman [9] showed that a positive compact nonquasinilpotent operator on a Banach lattice has a positive eigenvector corresponding to its spectral radius. As an extension of both results, we give sufficient conditions on such an operator in order that its spectral subspace corresponding to its spectral radius has a basis made exclusively of positive root vectors.
Relaxation time distribution function

Abstract The distribution function of relaxation time in disordered dielectrics has been calculated in the random field theory framework. For this purpose, we first consider the dynamics of single two-orientable electric dipole in a random electric field E in a disordered ferroelectric. The obtained dependence τ(E) made it possible to express the relaxation time distribution function F(τ) via the random field distribution function f(E). This function has been calculated self-consistently in the random field theory framework. Nonlinear random field contribution and effects of spatial correlations between the dipoles have also been taken into account. It was shown that nonlinear contribution of random field gives asymmetric shape of F(τ), while in linear case it is symmetric. Comparison of calculated F(τ) curves with those extracted from empirical Cole-Cole (CC), Davidson-Cole (DC), Kohlrausch-William-Watts (KWW) and Havriliak-Negami (HN) functions had shown, that they correspond to mixed ferroelectric-dipole glass (ferro-glass) phase with coexistence of short and long-range order. Different forms of F(τ) are determined by linear (CC) or nonlinear (DC, KWW, HN) contributions of random field.
Indirect Estimation of α-Stable Distributions and Processes

The alpha-stable family of distributions constitutes a generalization of the Gaussian distribution, allowing for asymmetry and thicker tails. Its practical usefulness is coupled with a marked theoretical appeal, as it stems from a generalized version of the central limit theorem in which the assumption of the finiteness of the variance is replaced by a less restrictive assumption concerning a somehow regular behavior of the tails. Estimation difficulties have however hindered its diffusion among practitioners. Since simulated values from alpha-stable distributions can be straightforwardly obtained, the indirect inference approach could prove useful to overcome these estimation difficulties. In this paper we provide a description of how to implement such a method by using a skew-t distribution as an auxiliary model. The indirect inference approach will be introduced in the setting of the estimation of the distribution parameters and then extended to linear time series models with alpha-stable disturbances. The performance of this estimation method is then assessed on simulated data. An application on time-series models for the inflation rate concludes the paper.
OBSERVATIONS OF THE [HNCS]/[HSCN] RATIO IN Sgr B2 AND TMC-1: EVIDENCE FOR LOW-TEMPERATURE GAS-PHASE CHEMISTRY

Millimeter observations of isothiocyanic acid (HNCS) and its higher energy isomer, thiocyanic acid (HSCN), have been carried out toward Sgr B2 and TMC-1 using the 12 m telescope of the Arizona Radio Observatory. For both species, the JKa,Kc = 80,8 → 70,7 and 90,9 → 80,8 transitions near 91–93 GHz and 103–106 GHz were mapped across a 6′ × 3′ region, centered near Sgr B2(M). Comparative mapping observations were also done for the JKa,Kc = 40,4 → 30,3 line of HNCO and HOCN near 84–87 GHz. In addition, the JKa,Kc = 70,7 → 60,6 and 80,8 → 70,7 transitions of both HNCS and HSCN were detected in TMC-1, the first identification of either molecule in a cold, dark cloud. Emission from HNCS and HSCN was found to be extended over the Sgr B2 cloud, with a single velocity component and a linewidth of ∼20–25 km s−1. Column densities derived for HSCN in Sgr B2 are typically Ntot ∼ (0.2–1) × 1013 cm−2, with Ntot ∼ (0.8–5) × 1013 cm−2 for the more stable isomer, HNCS. In TMC-1, these species have similar column densities of (6–8) × 1010 cm−2. The [HNCS]/[HSCN] abundance ratio ranges from 2 to 7 in Sgr B2, with a value of ∼1 in TMC-1. In contrast, the [HNCO]/[HOCN] ratio in Sgr B2 is ∼110–250. Gas-grain chemical models do not reproduce the observed abundances of the sulfur isomers in either source. Given the energy difference of over 3200 K between HNCS and HSCN, these observations suggest that both molecules are produced from gas-phase, ion–molecule chemistry with a common precursor, HNCSH+. The oxygen analogs, in contrast, probably have a more complex chemical network, perhaps involving the H2NCO+ precursor, which preferentially leads to HNCO.
Note on the One‐Dimensional Gas of Impenetrable Point‐Particle Bosons

A one‐dimensional gas of impenetrable point‐particle bosons is considered. An exact expression for the one‐particle density matrix is derived in terms of the Fredholm determinant and resolvent of a certain simple kernel. It is proved that for large r, the density matrix is bounded by const × r−4/π2, and that this implies the absence of a generalized Bose‐Einstein condensation, contrary to a recent approximate calculation by Girardeau, who first defined such a condensation.
Modeling Rate-Dependent Hysteresis for Magnetostrictive Actuator

The rate-dependent hysteresis exhibited by magnetostrictive actuator (MA) presents a challenge in modeling of these actuators. In this paper, a novel rate-dependent hysteresis model was proposed for magnetostrictive actuator. In the model, the modified Prandtl-Ishlinskii operator (PI) is combined with a second order ordinary differential equation in a cascaded structure. The modified PI operator is used to account for the static hysteresis, the connection between ODE and the rate-dependent energy loss was established, including the classical eddy current loss and the mechanical dynamics. Simulation results show a good agreement with the experiment ones.
On the structure of the fixed charge transportation problem

This work extends the theory of the fixed charge transportation problem (FCTP), currently based mostly on a forty-year-old publication by Hirsch and Danzig. This paper presents novel properties that need to be considered by those using existing, or those developing new methods for optimizing FCTP. It also defines the problem in an easier way, making it understandable to a wider spectrum of readers. While the analysis is limited to FCTP only, elements of it can easily be extended to the general fixed charge problem. Finally a novel, snap method for finding global minima for FCTPs with large fixed charge coefficients is introduced.
Riskante Strategie

Fresenius wird fast ausschließlich von der ebenfalls börsennotierten Fresenius Medical Care repräsentiert. Im vergangenen Jahr litt das Unternehmen unter dem starken Dollar und unter Restrukturierungs- Aufwendungen bei Fresenius Proserve. 2004 ist eine Ergebnissteigerung zu erwarten. Auf längere Sicht könnte die Strategie, das Dienstleistungsgeschäft auszubauen, erhebliche Risiken bergen.
The role of localized surface plasmon modes in the enhanced transmission of periodic subwavelength apertures

After reviewing the present understanding of the transmission properties of single apertures and the enhanced transmission through hole arrays, experimental results are presented which show how localized surface plasmon (LSP) modes of individual apertures contribute to the transmission peaks associated with the periodic arrays. In particular, it is shown that the surface plasmon polaritons (SPPs) of the periodic structure dominate the spectral signature of the arrays. The results also indicate that the LSP of each hole can interact and that this can be controlled by appropriate arrangement of the apertures in the array.
Fluid–structure interaction by the discontinuous‐Galerkin method for large deformations

A discontinuous‐Galerkin method for large deformation fluid–structure interaction problems is developed. The fluid–structure interface can be arbitrarily aligned relative to the fluid grid. An Eulerian description is used for the fluid with a Lagrangian description of the solid. Results are presented for several examples that show excellent agreement with immersed/fictitious element methods. Copyright © 2008 John Wiley & Sons, Ltd.
Upper Ocean Boundary‐Layer Flow Determined by Dye Diffusion

Dye patches released in the upper layer of seas indicate that the rate of increase with time of the second moments of concentration follows the Kolmogoroff's hypothesis for the inertial subrange. The curvature of dye patches photographed from the air can be explained as the vertically differential advection by the Ekman type wind‐driven currents in the upper boundary layer of the ocean. Striations of patches or plumes seem to be related to cellular motion generated by the short‐crested surface waves. The power spectra of concentration fluctuations determined across a dye plume show shift of the peak towards lower wave numbers (measured lateral to the plume) and its flattering with time. These spectral features are compared with a model similar to Heisenberg's energy transfer model by use of Kolmogoroff's energy spectrum.
Dynamitic cascaded FBG based filter used in DWDM networks

The characteristics of uniform fiber Bragg gratings (FBGs) is analyzed. The reflected spectra in apodized uniformly periodic FBGs are calculated and the double exposure technique is used in suppressing the sidelobes of uniform gratings. After that, the corresponding FBGs filters used in DWDM networks and systems are imprinted. Based on the apodized FBGs, a cascaded FBGs filter module is proposed, in which two, or more, pieces of identical FBGs, with the same central wavelength, same bandwidth and same reflectivity, are spliced in series and each FBG is equipped with tuning device. By controlling the tuning device, the module can act either as a tunable single channel filter with its central wavelength and/or bandwidth being tunable, or as a double channel filter with its central wavelength being tunable. The tested results demonstrated that the module can dynamically tuned in the range of several nanometers.
Boundary‐layer convection and diurnal variation of vertical‐velocity characteristics in the free troposphere

During the field experiment SOMARE‐99 (Sounding System Multifrequency Atmospheric Radar Experiment 1999), the troposphere above the Harz Mountains in Northern Germany was observed with the SOUSY VHF radar, with four microbarographs, and with 26 radiosondes launched every 3 h from nearby the radar site. This paper examines the 72 h period between 0000 UTC 25 May and 0000 UTC 28 May. Time series, root‐mean‐square values, and power spectra of radar‐observed vertical‐wind, w, fluctuations in the free troposphere and of pressure, p, fluctuations at the surface are presented and discussed. A pronounced diurnal cycle was observed: standard deviations (from 1 h periods) were about 10 cm s−1 (w) and 2 Pa (p) at night and up to 60 cm s−1 and 6 Pa during daytime. This is seen as evidence for the relevance of boundary‐layer convection for short‐period gravity waves in the free troposphere. Frequency spectra of w show a power‐law drop‐off beyond the Brunt‐Väisälä frequency with logarithmic slopes close to ‐5/3 at moderate and strong wind speeds and down to ‐3 or ‐4 at weak winds (smaller than 5 m s−1), supporting earlier work on the effects of Doppler shift on Eulerian gravity‐wave spectra. The w spectra, which have been calculated from 8 h long w time series (sampling period 1 min), have a noise floor of 10−3 m2s−2Hz−1 or less. This corresponds to an uncorrelated noise with a standard deviation of 3 mm s−1 for the 1 min samples. The concept of gravity‐wave intermittency is introduced, in analogy to a well‐established concept in turbulence physics. It is demonstrated how this concept can be used to distinguish turbulence from gravity waves empirically.
Three-photon W-state

Abstract Multiphoton entanglement is the basis of many quantum communication schemes, quantum cryptographic protocols, and fundamental tests of quantum theory. For entangled three-qubit states it has been shown that there are two inequivalent classes of states, under stochastic local operations and classical communications. The classes are represented by the GHZ- and W-state. The GHZ-state has been used to prove Bell's theorem without inequality. Contrary to the GHZ-state, the W-state shows high robustness of entanglement against photon loss. Here we show the first experimental results on the observation of the polarization entangled three-photon W-state from spontaneous parametric down-conversion.
An Covariance Spectrum Sensing Algorithm Based on DMM / MME Mixture Features

With the research of Random Matrix Theory (RMT), many RMT -based covariance detection algorithms have been proposed and applied to spectrum sensing. As a blind detection algorithm, the detection performance in practice is often susceptible to environmental factors due to the approximation of threshold calculation. In view of this problem, some scholars have proposed to use machine learning to improve the covariance detection, so as to obtain high environmental adaptability. In this paper, we propose a covariance spectrum sensing algorithm with judgment statistics in maximum-minimum eigenvalue algorithm (MME) and difference between the maximum eigenvalue and the minimum eigenvalue algorithm (DMM) as hybrid features, which takes the both the quotient and difference of the maximum minimum eigenvalue of the covariance matrix as the feature vector for classification, and then trained and classified by SVM. Simulation results show that the proposed algorithm improves significantly compared to the traditional covariance detection. Moreover, compared with the existing covariance in combination with SVM detection algorithm, the two features selected in this paper have better differentiation and better environmental adaptability under low SNR.
Oscillator strengths for Y I and Y II and the solar abundance of yttrium.

Oscillator strengths have been determined from measurements of radiative lifetimes and branching ratios for 154 lines of Y I and 66 lines of Y II. These data are used, together with equivalent widths measured on the Jungfraujoch solar atlas, to perform a new determination of the solar abundance of yttrium: A/sub Y/ = 2.24 +- 0.03.
Deep Reinforcement Learning Driven Aggregate Flow Entries Eviction in Software Defined Networking

Software-Defined Networking (SDN) separates control from network elements and logically centralizes it in SDN controller to provide global view and control of the network. Network elements, such as switches, only forward data using entries in the flow tables that are installed by the controller. The capacity of flow tables is limited and requires continuous management. Several studies have proposed eviction strategies to make space for new entries in the flow tables, but they assume 1:1 mapping between entries and incoming flows. This assumption is a major limitation, as in real networks many incoming flows can be handled by a single Aggregate Flow Entry (AFE). This paper handles this limitation by proposing Deep Reinforcement Learning (DRL) framework for eviction of AFEs. The proposed framework calculates the degree of AFEs (i.e., how many flows it entertains) along with other parameters to select AFE for eviction, where main objective is to minimize flow table overflows. The experiment results show that the proposed framework reduces the number of overflows by 37%, flow reinstallation by 87%, and the control signaling overhead by 45 % compared to the Random and Least Recently Used Algorithm (LRU).
Matlab Platform Remote Control System Experiments

The paper proposes the remote experiment that enables a student to conduct the physical control system experiment through the internet. The remote experiment is designed using MATLAB platform to create the user interface and to analyze the results. A DC motor controlled by PI controller is utilized as the physical system for demonstrating the effectiveness of the proposed system. Interface module with a dsPIC microcontroller is in charge of implementing a control loop and connecting between a user interface and a physical system. The experimental results reveal that there are a little delay times in live video monitoring but it does not affect the closed-loop control system and it can still be run in real time.
Precision measurement of the fine structure constant based on atom interferometry

Preliminary result of the fine structure constant measurement is presented, which is based on an atom interferometric method. The value for the fine structure constant is derived from the precision measurement of the recoil velocity of cesium atoms due to the coherent scattering of a single photon. The current uncertainty of the measurement is 7.4 ppb in /spl alpha/. The analysis of the major systematic effects is presented and the last yet not completely resolved potential systematic effect is discussed. It is due to cold cesium background atoms constituting a dielectric environment with non-unity index of refraction. Among the other effects discussed, especially this systematic effect may be of importance for future high precision atom interferometers like HYPER aiming at the sub-ppb level of uncertainty in the determination of /spl alpha/.
A Review Paper on Cloud Computing

Cloud computing has taken its place all over the IT industries. It is an on-demand internet-based computing service that provides the maximum result with minimum resources cloud computing provides a service that does not require any physical close to the computer hardware. Cloud Computing is a product of grid, distributed, parallel, and ubiquitous computing. This paper introduces the concepts, history pros, and cons of cloud computing. Now coming to IoT, it can be any device equipment, or object which connects us with the cloud using the internet or with another device that is connected. It has sensors, processing ability, software, and many technologies which can be used to share and fetch data or information with other devices and servers over the internet. Nowadays big companies are using cloud services for storing their data because it is easy to manage their data easily without any additional costs. Cloud computing provides us the flexibility to play with our data and gives us more freedom with storage, access, and management. In this paper, we will see the advantages and disadvantages of using the cloud, how IoT is useful in cloud systems, and how we can overcome the problems related to the cloud.
Validating TTGO T-Wristband Smart Band for the Lee Silverman Voice Treatment-BIG and Functional Activities

Inertial Measurement Units have become one of the most widely used instruments in Human Activity Recognition and clinical applications. Their performance needs to be validated against gold standard systems to be reliably used for any particular application. In this study, we validated MPU9250 in TTGO T-Wristband smart band (Shenzhen Xinyuan Electronic Technology© Ltd.) against MetaMotionR (MBIENTLABO, San Fransisco, USA) for the Lee Silverman Voice Treatment-BIG (LSVT-BIG) and functional activities. The validation metrics in this study are the Pearson’s correlation and Root Mean Square Error (RMSE) between acceleration and gyroscope readings, the Bland-Altman plots for the error in acceleration magnitudes, and linear regression on the error in acceleration magnitudes. Our results show that sensor readings between the IMUs were highly correlated, with a few exceptions. RMSE was mostly less than 0. 05g and 15°/s. Proportional biases between the error in acceleration magnitudes and the mean acceleration magnitudes were mostly insignificant, with the significant ones having a slope of no greater than 0.1 over a range of at most 2g. Our findings show that the TTGO T-Wristband is a valid choice for kinematic measurements for LSVT-BIG and functional activities.
A Signal Generator and Down-Conversion Mixer / TIA Unit for a 5.8-GHz FMCW Receiver in 65nm CMOS

This paper presents a 5.8 GHz FMCW signal generator with a maximum bandwidth of 275 MHz along with a down-conversion mixer / TIA with a peak homodyne structure down-conversion gain of 13.5 dB and a maximum baseband BW of 150 MHz. The FMCW signal is achieved by a ramp generator signal applied to the varactor bank of a VCO tank. The VCO differential signals are injected into a non-overlapping 50% duty cycle square wave generator which provides the desired LO signals applied to a passive current mixer. The FMCW signal generator and down-conversion mixer / TIA unit is implemented with the size of $\boldsymbol{0.3}\mathbf{mm}\times \boldsymbol{1.5}\mathbf{mm}$ in 65 nm CMOS technology. The VCO RF output looped back to RF port of the mixer and the 400 KHz baseband signal at the output of the receiver unit is measured by a low frequency oscilloscope and FFT extraction.