Miracle-dz/UniFAR-FTUs huggingface dataset:
Estimating time-varying parameters by the Kalman filter based algorithm: stability and convergence

Convergence and stability properties of the Kalman filter-based parameter estimator are established for linear stochastic time-varying regression models. The main features are: both the variances and sample path averages of the parameter tracking error are shown to be bounded; the regression vector includes both stochastic and deterministic signals, and no assumptions of stationarity or independence are requires; and the unknown parameters are only assumed to have bounded variations in an average sense. >
On the Existence of Friendship Hypergraphs

A 3‐uniform friendship hypergraph is a 3‐uniform hypergraph in which, for all triples of vertices x, y, z there exists a unique vertex w, such that xyw , xzw, and yzw are edges in the hypergraph. Sós showed that such 3‐uniform friendship hypergraphs on n vertices exist with a so‐called universal friend if and only if a Steiner triple system, S(2,3,n−1) exists. Hartke and Vandenbussche used integer programming to search for 3‐uniform friendship hypergraphs without a universal friend and found one on 8, three nonisomorphic on 16 and one on 32 vertices. So far, these five hypergraphs are the only known 3‐uniform friendship hypergraphs. In this paper we construct an infinite family of 3‐uniform friendship hypergraphs on 2k vertices and 2k−1(3k−1−1) edges. We also construct 3‐uniform friendship hypergraphs on 20 and 28 vertices using a computer. Furthermore, we define r‐uniform friendship hypergraphs and state that the existence of those with a universal friend is dependent on the existence of a Steiner system, S(r−1,r,n−1) . As a result hereof, we know infinitely many 4‐uniform friendship hypergraphs with a universal friend. Finally we show how to construct a 4‐uniform friendship hypergraph on 9 vertices and with no universal friend.
Delay Range-Dependent Stability Analysis for Markovian Jumping Stochastic Systems with Nonlinear Perturbations

This article addresses the problem of delay-dependent stability for Markovian jumping stochastic systems with interval time-varying delays and nonlinear perturbations. The delay is assumed to be time-varying and belongs to a given interval. By resorting to Lyapunov–Krasovskii functionals and stochastic stability theory, a new delay interval-dependent stability criterion for the system is obtained. It is shown that the addressed problem can be solved if a set of linear matrix inequalities (LMIs) are feasible. Finally, a numerical example is employed to illustrate the effectiveness and less conservativeness of the developed techniques.
Die vielen Väter des Transistors. Meilensteine in der Geschichte des Festkörperverstärkers

Vor hundert Jahren wurde der zweifache Physik‐Nobelpreisträger John Bardeen geboren, der zusammen mit William Shockley und Walter Brattain als Vater des Transistors gilt. Die Vorgeschichte des Festkörperverstärkers ist jedoch komplex. Zum Konzept des Feldeffekt‐Transistors leisteten deutsche Physiker zuvor in den zwanziger und dreißiger Jahren entscheidende Beiträge: Julius Edgar Lilienfeld, Oskar Heil und Heinrich Welker meldeten wichtige Patente an. Robert Pohl und Rudolf Hilsch bauten in Göttingen wahrscheinlich den ersten funktionsfähigen Festkörperverstärker auf Basis eines Kaliumbromid‐Kristalls. Welker und Herbert Franz Mataré arbeiteten 1946 im Auftrag von Westinghouse in Paris an Transistoren. Den ersten funktionsfähigen Germaniumtransistor realisierten jedoch Shockley, Bardeen und Brattain 1947 an den Bell Labs.
CO2‐laser radiation absorption by metal gratings

It is shown that CO2‐laser radiation‐induced periodic structures on the surface of metallic targets result in a dramatic increase (by up to one order of magnitude) in the sample absorptivity. This behavior has made it possible to gain new insight into the thermal coupling of powerful CO2‐laser radiation with the initially highly reflectant metallic surfaces.
Gauge invariance in the interaction between atoms and few-cycle laser pulses

It is shown that certain unitary gauge operations that are normally of negligible importance in the theory of laser-atom interactions become significant for pulses containing only a few cycles, and it is discussed how to make gauge invariant predictions in general, and in particular in the velocity and length gauges, and in the Henneberger frame.
The mechanism of threshold switching in amorphous alloys

This paper surveys the characteristics of threshold switching systems and examines the evidence for threshold switching as an electronic process. A semiquantitative model is proposed for the nature of the ON\char22{}state. The OFF\char22{}ON transition is also discussed in the light of recent experimentation, as are the principal aspects of the problem still in need of furthur clarification.
Interventionism and Supervenience: A New Problem and Provisional Solution

The causal exclusion argument suggests that mental causes are excluded in favour of the underlying physical causes that do all the causal work. Recently, a debate has emerged concerning the possibility of avoiding this conclusion by adopting Woodward's interventionist theory of causation. Both proponents and opponents of the interventionist solution crucially rely on the notion of supervenience when formulating their positions. In this article, we consider the relation between interventionism and supervenience in detail and argue that importing supervenience relations into the interventionist framework is deeply problematic. However, rather than reject interventionist solutions to exclusion wholesale, we wish to propose that the problem lies with the concept of supervenience. This would open the door for a moderate defence of the interventionist solution to the exclusion argument.
Focal plane location in digital holography

The correlation coefficient method is introduced to locate the focal plane in digital particle holography. It uses the fact that the correlation coefficient is maximum at the focal plane. The factors influencing this method are discussed with a numerical simulation of holograms. For real holograms, the Wiener filter was first proposed to process both recorded holograms and reconstructed images. The application results using the dot array target showed that the Wiener filter is a very effective tool for processing holography-related images. The effects of the dot size and the object distance on the errors in the determination of the focal plane by the correlation coefficient method were investigated by using the calibration target.
Searches for Active and Sterile Neutrinos in Beta-Ray Spectra

Although neutrinos are probably the most abundant particles of the universe their mass is yet unknown. The oscillation experiments proved that at least one of the neutrino mass states is heavier than 0.05 eV. Strongly model dependent interpretations of cosmological observations yielded for the sum of the neutrino mass states the values between 0.12 and 1.7 eV. The almost model independent analyses of measured tritium \b{eta}- spectra provided the upper limit of the effective electron neutrino mass of 2 eV. The upcoming KATRIN experiment aims to achieve ten times higher sensitivity. In this review, we try to summarize the experience of two generations of \b{eta}-ray spectroscopists who improved the limit of the neutrino mass by three orders of magnitude. We describe important steps in the development of radioactive sources and electron spectrometers, and recapitulate the lessons from now disproved claims for the neutrino of 30 eV mass and the 17 keV neutrino with an admixture larger than 0.07 %. We also pay attention to new experimental approaches as well as to searches for hypothetical eV and keV sterile neutrinos.
Increase of temperature due to Joule heating during current-induced magnetization switching of an MgO-based magnetic tunnel junction

Three-dimensional numerical calculations based on the finite element method are performed to calculate the increase of temperature caused by Joule heating during the current-induced magnetization switching of an MgO-based magnetic tunnel junction. The increase of temperature is found to be significantly large (the maximum being 145K) at critical conditions for the current-induced magnetization switching. The temperature increase also differs greatly, depending on the critical condition, requiring a correction in calculating the thermal stability parameter using the Slonczewski equation. After the correction, the thermal stability parameter increases substantially from 67 to 76.
Information propagation in a quantum system: examples of open spin-1/2 chains

If information is encoded into the state of the subsystem S of a quantum system initially (at t = 0), then it becomes distributed over the whole quantum system at t > 0 due to quantum interactions. Consequently, this information, in general, can be extracted, either completely or partially, from any subsystem of a quantum system. We suggest a method of extraction of information, which is based on the polarization measurements on the receiver R.
Metamaterial-based gradient index beam steerers for terahertz radiation

We designed, fabricated, and optically characterized single and double layer metamaterial-based gradient index beam steerers for terahertz radiation. We measured a maximal deflection angle of 6°. The operation bandwidth of the beam steerers was 300 GHz around a center frequency of 1.3 THz. Within this bandwidth, the amplitude transmission was higher than 50%. Due to a thickness of only 100 μm or below, the implemented beam steerers are ideally suited for integration in compact terahertz measurement systems.
Frontiers in optical stimulation of neural tissues: past, present, and future

Since lasers were first used in medicine and biomedical related research there have been a variety of documented effects following the irradiation of neural tissues. The first systematic studies to report the direct stimulatory effect of infrared light on neural tissues were performed by researchers at Vanderbilt University in the rat sciatic nerve. These initial studies demonstrated a set of associated advantages of standard stimulation methods, which lead to much excitement and anticipation from the neuroscience community and industry. The inception of this new field included a partnership between industry and academia to foster the development, not only of the applications but also a series of devices to support the research and ultimate commercialization of technology. Currently several institutions are actively utilizing this technique in various applications including in the cochlear and vestibular systems. As more researchers enter the field and new devices are developed we anticipate the number of applications will continue to grow. Some of the next steps will include the establishment of the safety and efficacy data to move this technique to clinical trials and human use.
A Multimodal Knowledge-Based Deep Learning Approach for MGMT Promoter Methylation Identification

Glioblastoma Multiforme (GBM) is considered one of the most aggressive malignant tumors, characterized by a tremendously low survival rate. Despite alkylating chemotherapy being typically adopted to fight this tumor, it is known that O(6)-methylguanine-DNA methyltransferase (MGMT) enzyme repair abilities can antagonize the cytotoxic effects of alkylating agents, strongly limiting tumor cell destruction. However, it has been observed that MGMT promoter regions may be subject to methylation, a biological process preventing MGMT enzymes from removing the alkyl agents. As a consequence, the presence of the methylation process in GBM patients can be considered a predictive biomarker of response to therapy and a prognosis factor. Unfortunately, identifying signs of methylation is a non-trivial matter, often requiring expensive, time-consuming, and invasive procedures. In this work, we propose to face MGMT promoter methylation identification analyzing Magnetic Resonance Imaging (MRI) data using a Deep Learning (DL) based approach. In particular, we propose a Convolutional Neural Network (CNN) operating on suspicious regions on the FLAIR series, pre-selected through an unsupervised Knowledge-Based filter leveraging both FLAIR and T1-weighted series. The experiments, run on two different publicly available datasets, show that the proposed approach can obtain results comparable to (and in some cases better than) the considered competitor approach while consisting of less than 0.29% of its parameters. Finally, we perform an eXplainable AI (XAI) analysis to take a little step further toward the clinical usability of a DL-based approach for MGMT promoter detection in brain MRI.
Moving contact lines in liquid/liquid/solid systems

A general mathematical model which describes the motion of an interface between immiscible viscous fluids along a smooth homogeneous solid surface is examined in the case of small capillary and Reynolds numbers. The model stems from a conclusion that the Young equation, σ1 cos θ = σ2 − σ3, which expresses the balance of tangential projection of the forces acting on the three-phase contact line in terms of the surface tensions σi and the contact angle θ, together with the well-established experimental fact that the dynamic contact angle deviates from the static one, imply that the surface tensions of contacting interfaces in the immediate vicinity of the contact line deviate from their equilibrium values when the contact line is moving. The same conclusion also follows from the experimentally observed kinematics of the flow, which indicates that liquid particles belonging to interfaces traverse the three-phase interaction zone (i.e. the ‘contact line’) in a finite time and become elements of another interface – hence their surface properties have to relax to new equilibrium values giving rise to the surface tension gradients in the neighbourhood of the moving contact line. The kinematic picture of the flow also suggests that the contact-line motion is only a particular case of a more general phenomenon – the process of interface formation or disappearance – and the corresponding mathematical model should be derived from first principles for this general process and then applied to wetting as well as to other relevant flows. In the present paper, the simplest theory which uses this approach is formulated and applied to the moving contact-line problem. The model describes the true kinematics of the flow so that it allows for the ‘splitting’ of the free surface at the contact line, the appearance of the surface tension gradients near the contact line and their influence upon the contact angle and the flow field. An analytical expression for the dependence of the dynamic contact angle on the contact-line speed and parameters characterizing properties of contacting media is derived and examined. The role of a ‘thin’ microscopic residual film formed by adsorbed molecules of the receding fluid is considered. The flow field in the vicinity of the contact line is analysed. The results are compared with experimental data obtained for different fluid/liquid/solid systems.
Global stability of the two-dimensional flow over a backward-facing step

Abstract The two-dimensional, incompressible flow over a backward-facing step is considered for a systematic variation of the geometry covering expansion ratios (step to outlet height) from 0.25 to 0.975. A global temporal linear stability analysis shows that the basic flow becomes unstable to different three-dimensional modes depending on the expansion ratio. All critical modes are essentially confined to the region behind the step extending downstream up to the reattachment point of the separated eddy. An energy-transfer analysis is applied to understand the physical nature of the instabilities. If scaled appropriately, the critical Reynolds number approaches a finite asymptotic value for very large step heights. In that case centrifugal forces destabilize the flow with respect to an oscillatory critical mode. For moderately large expansion ratios an elliptical instability mechanism is identified. If the step height is further decreased the critical mode changes from oscillatory to stationary. In addition to the elliptical mechanism, the strong shear in the layer emanating from the sharp corner of the step supports the amplification process of the critical mode. For very small step heights the basic state becomes unstable due to the lift-up mechanism, which feeds back on itself via the recirculating eddy behind the step, resulting in a steady critical mode comprising pronounced slow and fast streaks.
Adventures of a Mathematician

This autobiography of mathematician Stanislaw Ulam, one of the great scientific minds of the twentieth century, tells a story rich with amazingly prophetic speculations and peppered with lively anecdotes. As a member of the Los Alamos National Laboratory from 1944 on, Ulam helped to precipitate some of the most dramatic changes of the postwar world. He was among the first to use and advocate computers for scientific research, originated ideas for the nuclear propulsion of space vehicles, and made fundamental contributions to many of today's most challenging mathematical projects. With his wide-ranging interests, Ulam never emphasized the importance of his contributions to the research that resulted in the hydrogen bomb. Now Daniel Hirsch and William Mathews reveal the true story of Ulam's pivotal role in the making of the 'Super,' in their historical introduction to this behind-the-scenes look at the minds and ideas that ushered in the nuclear age. It includes an epilogue by Francoise Ulam and Jan Mycielski that sheds new light on Ulam's character and mathematical originality.
Hot Shocked Gas along the Jets of NGC 4258 (M106)

The ROSAT High Resolution Interferometer (HRI) and Position Sensitive Proportional Counter (PSPC) detectors have been used to study the soft X-ray emission of the nearby SABbc galaxy NGC 4258 (M106). The helically twisted, nuclear jets, previously detected in radio continuum and visual emission-line studies, are found to dominate the X-ray images. After correcting pointing errors of up to +/- 7 sec in our HRI observation, we find that the southeast jet is spatially unresolved transversely along much of its 2.5 min (5 kpc) length. The northwest jet is more diffuse, and the extensive radio 'plateaus' also emit X-rays. The energy spectrum of the jets from the PSPC exposure is noisy but is best fitted as a Raymond-Smith plasma with kT = 0.3 keV, log N(sub H) approximately = 20.0/sq cm, and luminosity 1.6 x 10(exp 40) ergs/s between 0.1 and 2.4 keV. Gas at this temperature can arise from planar shocks of 500 km/s and may have been entrained as the jets scrape along the molecular clous that are known to be adjacent to the jets. The range of radial velocities from our published visual emission-line spectra of the jet are consistent with such a shock speed. We estimate that the mass of hot gas in the jets is 6 x 10(exp 4) (1/cc/n(sub e)) solar mass, with n(sub e) the average electron density. The inferred pressure of hot gas in the southeast jet may be similar to the radio equipartition pressure and to the ambient pressure of the interstellar medium (ISM). The X-ray spectral fit is poor above 0.7 keV and requires an additional hard component that peaks near the nucleus.
Importance Sampling for Estimating Exact Probabilities in Permutational Inference

Abstract This article discusses importance sampling as an alternative to conventional Monte Carlo sampling for estimating exact significance levels in a broad class of two-sample tests, including all of the linear rank tests (with or without censoring), homogeneity tests based on the chi-squared, hypergeometric, and likelihood ratio statistics, the Mantel—Haenszel trend test, and Zelen's test for a common odds ratio in several 2 × 2 contingency tables. Inference is based on randomly selecting 2 × k contingency tables from a reference set of all such tables with fixed marginals. Through a network algorithm, the tables are selected in proportion to their importance for reducing the variance of the estimated Monte Carlo p-value. Spectacular gains, up to four orders of magnitude, are achieved relative to conventional Monte Carlo sampling. The technique is illustrated on four real data sets.
On Bootstrap Confidence Intervals in Nonparametric Regression

priate. In this paper we point out some of the theoretical advantages of pivoting. They include a reduction in the error of the bootstrap distribution function estimate, from n - 1/2 to n- lh-1/2 (where h denotes bandwidth); and a reduction in coverage error of confidence intervals, from either n-L 1/2h- 1/2 or n- 1/2h1/2 (depending on which nonpivotal method is used) to n-1. Several comparisons are drawn with the case of nonparametric density estimation, where a pivotal approach also reduces errors associated with confidence intervals, but where the orders of magnitude of the respective errors are quite different from their counterparts for nonparametric regression.
A batch means methodology for estimation of a nonlinear function of a steady-state mean

We study the estimation of steady-state performance measures from an \frak{R} d -valued stochastic process Y = {Y(t): t \ge 0} representing the output of a simulation. In many applications, we may be interested in the estimation of a steady-state performance measure that cannot be expressed as a steady-state mean r, e.g., the variance of the steady-state distribution, the ratio of steady-state means, and steady-state conditional expectations. These examples are particular cases of a more general problem---the estimation of a (nonlinear) function f(r) of r. We propose a batch-means-based methodology that allows us to use jackknifing to reduce the bias of the point estimator. Asymptotically valid confidence intervals for f(r) are obtained by combining three different point estimators (classical, batch means, and jackknife) with two different variability estimators (classical and jackknife). The performances of the point estimators are discussed by considering asymptotic expansions for their biases and mean squared errors. Our results show that, if the run length is large enough, the jackknife point estimator provides the smallest bias, with no significant increase in the mean squared error.
Estimation of the Interaction Forces in a Compliant pHRI Gripper

Physical human–robot interaction (pHRI) is an essential skill for robots expected to work with humans, such as assistive or rescue robots. However, due to hard safety and compliance constraints, pHRI is still underdeveloped in practice. Tactile sensing is vital for pHRI, as constant occlusions while grasping make it hard to rely on vision or range sensors alone. More specifically, measuring interaction forces in the gripper is crucial to avoid injuries, predict user intention and perform successful collaborative movements. This work exploits the inherent compliance of a gripper with four underactuated fingers which was previously designed by the authors and designed to manipulate human limbs. A new analytical model is proposed to calculate the external interaction forces by combining all finger forces, which are estimated by using the gripper proprioceptive sensor readings uniquely. An experimental evaluation of the method and an example application in a control system with active compliance have been included to evaluate performance. The results prove that the proposed finger arrangement offers good performance at measuring the lateral interaction forces and torque around the gripper’s Z-axis, providing a convenient and efficient way of implementing adaptive and compliant grasping for pHRI applications.