Miracle-dz/UniFAR-FTUs huggingface dataset:
Measuring fuzziness: An evaluation problem

The measurement of fuzziness is treated as an evaluation problem. Fuzziness measures can be seen as evaluation mappings, more specifically as approximate solutions of this evaluation problem, satisfying some additional boundary conditions. In this way it is also possible to describe fuzziness in a qualitative manner. A general framework is created in which the most important classes of fuzziness measures, i.e., entropy measures and energy measures, easily fit. The essence of measuring fuzziness is thus reduced to finding a quasi or partial ordering that compares the different alternatives according to some aspect of their fuzziness. Special attention is paid to the quasi or partial orderings underlying entropy measures. The partial ordering of A. De Luca and S. Termini (1979) and some improved versions of it are discussed. The approach of E. Czogala et al. (1982) to energy measures is also discussed and extended. <<ETX>>
Spatial features of the wall-normal structures in a turbulent boundary layer

Coherent wall-normal structures in a turbulent boundary layer (TBL) have been investigated by scrutinizing a direct numerical simulation (DNS) dataset with Reθ = 2500. It was found that groups of hairpin legs induce wall-normal-aligned structures and these large-scale regions are mostly induced by the combination of the attached and detached vortical structures. By using the feature extraction algorithm, we found that more than approximately 60% of the attached momentum regions extend beyond the log region, while most of the detached regions formed locally away from the wall have relatively short wall-normal extent. The two-point correlation of the streamwise velocity fluctuations showed that the wall-normal length scales vary linearly with the distance from the wall, and, finally, the two-point correlations between the signed swirling motions showed that interactions between counterrotating vortices are predominant throughout the boundary layer and especially frequent in the near-wall region.
Action recognition via cumulative histogram of multiple features

Spatial-temporal interest points (STIPs) are popular in human action recognition. However, they suffer from difficulties in determining size of codebook and losing much information during forming histograms. In this paper, spatial-temporal interest regions (STIRs) are proposed, which are based on STIPs and are capable of marking the locations of the most "shining" human body parts. In order to represent human actions, the proposed approach takes great advantages of multiple features, including STIRs, pyramid histogram of oriented gradients and pyramid histogram of oriented optical flows. To achieve this, cumulative histogram is used to integrate dynamic information in sequences and to form feature vectors. Furthermore, the widely used nearest neighbor and AdaBoost methods are employed as classification algorithms. Experiments on public datasets KTH, Weizmann and UCF sports show that the proposed approach achieves effective and robust results.
Measuring a completely unknown phase with sub-shot-noise precision in the presence of loss

We present a practical scheme for measuring completely unknown phases with a precision beyond the shot-noise limit even in the presence of loss. Our scheme consists of sending a sequence of unentangled particles and NOON states through an interferometer and analyzing the measurement outcomes using a Bayesian analysis. We compare our results with two recent schemes [L. Pezze and A. Smerzi, Europhys. Lett. 78, 30004 (2007); B. L. Higgins et al., Nature (London) 450, 393 (2007)] that are closely related but operate in the lossless regime. We show that our technique outperforms the previous schemes when even a modest amount of loss is present and so may prove to be a valuable technique for making precision measurements beyond the classical limit in a range of practical scenarios.
Integral transforms with the Legendre function of the first kind in the kernels on -spaces

This paper is devoted to the study of the one-dimensional integral transform and three of its modifications, involving the Legendre function of the first kind with complex γ, δ, Re(γ)<1, in the kernels, in the space of Lebesgue measurable functions f on such that Mapping properties such as the boundedness, the range, the representation and the inversion of the considered transforms are established.
Nonlinear differential−difference equations

A method is presented which enables one to obtain and solve certain classes of nonlinear differential−difference equations. The introduction of a new discrete eigenvalue problem allows the exact solution of the self−dual network equations to be found by inverse scattering. The eigenvalue problem has as its singular limit the continuous eigenvalue equations of Zakharov and Shabat. Some interesting differences arise both in the scattering analysis and in the time dependence from previous work.
Novel layered two-dimensional semiconductors as the building blocks for nano-electronic/photonic systems

Layered two-dimensional (2D) semiconductors beyond graphene have been emerging as potential building blocks for the next-generation electronic/photonic applications. Representative metal chalcogenides, including the widely studied MoS2, possess similar layered crystal structures with weak interaction between adjacent layers, thus allowing the formation of stable thin-layer crystals with thickness down to a few or even single atomic layer. Other important chalcogenides, involving earth-abundant and environment-friendly materials desirable for sustainable applications, include SnS2 (band gap: 2.1 eV) and SnS (band gap: 1.1 eV). So far, commonly adopted for research purpose are mechanical and liquid exfoliation methods for creating thin layers of such 2D semiconductors. Most recently, chemical vapor deposition (CVD) was attracting significant attention as a practical method for producing thin films or crystal grains of MoS2. However, critical yet still absent is an effective experimental approach for controlling the positions of thin crystal grains of layered 2D semiconductors during the CVD process. Here we report the controlled CVD synthesis of thin crystal arrays of representative layered semiconductors (including SnS2 and SnS) at designed locations on chip, promising large-scale optoelectronic applications. Our work opens a window for future practical applications of layered 2D semiconductors in integrated nano-electronic/photonic systems.
VAr planning using genetic algorithm and linear programming

A combined methodology consisting of successive linear programming (SLP) and a simple genetic algorithm (SGA) solves the reactive planning problem. The problem is divided into operating and planning subproblems; the operating subproblem, which is a nonlinear, ill-conditioned and nonconvex problem, consists of determining the voltage control and the adjustment of reactive sources. The planning subproblem consists of obtaining the optimal reactive source expansion considering operational, economical and physical characteristics of the system. SLP solves the optimal reactive dispatch problem related to real variables, while SGA is used to determine the necessary adjustments of both the binary and discrete variables existing in the modelling problem. Once the set of candidate busbars has been defined, the program implemented gives the location and size of the reactive sources needed, if any, to maintain the operating and security constraints.
Powder x‐ray diffraction of two‐dimensional materials

An analytic solution for the normalized intensity for powder x‐ray diffraction has been obtained for a simple two‐dimensional lattice using a linear approximation for the interference function. The analytic solution, where the Bragg peaks are strongly asymmetric, is compared to computer simulations using the Debye formula, and is shown to be in closer agreement than earlier numerical solutions by Warren and others. For a two‐dimensional structure consisting of more than one monolayer of atoms, the shape of the Bragg peaks is modulated by the structure factor. This structure factor modulation provides a continuous plot of the structure factor over the range of the diffraction tail and thus provides valuable information about the structure of the layer. It is demonstrated that because of structure factor modulation the Warren expression which relates the width of Bragg peaks to layer size cannot be used for a two‐dimensional sheet with more than one layer of atoms, and it is proposed in such cases that meas.
Effects of surface cooling on the spreading of lava flows and domes

Scaling analyses describe the evolution of an extrusion of viscous or plastic fluid in the presence of surface cooling and solidification, under the assumption that the flows consist of two components: an isothermal interior and a surface crust. The ‘crust’ is a complex thermal and rheological boundary layer which we model using a viscous, plastic or brittle rheology. These models are thought to be relevant to some types of lava flows and address the effects of cooling on their morphology and rate of advance of the flow front. They show that effects of crust strength will dominate over both viscous and yield stresses in the interior when the ratio of crust thickness to flow length exceeds the ratio of effective yield stress of the crust to basal shear stress exerted on the bulk of the flow, a condition that appears likely to be met by many lava flows and small outgrowths on large flows. Similarity solutions are compared with measurements on the spreading of extrusions of wax beneath cold water in the laboratory, where the extruded liquid is viscous but develops a solid crust. Crust strength provides the dominant retarding force for the wax flows in cases where surface solidification occurs rapidly compared with lateral advection. These conditions give flows topped by sheets of solid that buckle or rift apart, or extrusions that enlarge by small bulbous outgrowths (analogous to ‘pillows’ on submarine lavas and ‘toes’ on some sub-aerial basalt flows). A comparison of the models with data for the growth of lava domes in the craters of Mount St Helens and Soufrière of St Vincent volcanoes reveals that spreading of those domes was not controlled by stresses in the flow interior. Instead the data are consistent with a balance between gravity and yield stresses in a thin crustal layer over most of the growth period.
Multiple crossed-beam ultrasound Doppler velocimetry

A new ultrasound Doppler technique for obtaining calibrated 3D flow velocity information is reported. Theoretical expressions are derived for the expected Doppla shift and the spectral spread under a variety of flow conditions. Experimental results using a revolv-) ing turntable demonstrated the linearity of velocity detection, the ability to resolve an arbitrary velocity vector, and conrimed the theoretical predictions of spectral spread.
Two-Layer Wall Model for Large-Eddy Simulations of Flow over Rough Surfaces

Two-layer zonal near-wall treatment for flow over rough surfaces is proposed in a generalized coordinate largeeddy simulation framework. Rotta’s [Rotta, J. C. , “Turbulent Boundary Layers in Incompressible Flow,” Progress in Aeronautical Sciences, Vol. 2, 1962, pp. 1–220. ] approach to amplify the mixing length near the wall is used to model the eddy viscosity in the inner layer. Calculations are performed in a rod-roughened channel at high flow Reynolds numbers in the range of 6000 to 56,000 and in the fully rough regime. An equivalent sand-grain roughness is used to correlate the amplification in the wall shear stress with the roughness geometry. The roughness wall model predicts the skin-friction coefficient and the mean velocity profile, in close agreement with experiments. Turbulence statistics are also predicted with good accuracy. For the lowest Reynolds number investigated in the current study, the spatial resolution required bywall-modeled large-eddy simulation is three orders ofmagnitude smaller thanwith a direct simulation on the same geometry that resolves the roughness elements. This results in large savings in computational cost.
Evaluation of the Hantush's M(α, β) function using binomial coefficients

A new approach is presented for calculating Hantush's M function which arises often in analytical solutions for groundwater pumping models. We develop an algorithm of implementing Hantush's M function calculations, in which binomial expansion theorem is employed. This algorithm is advantageous in the accurate calculation of Hantush's M function. The formulae by which Hantush's M function is expressed are uniform, and their application to the calculation of dynamics of groundwater mounding beneath recharge zones presents no difficulties using a computer. Finally, simple results are presented and discussed.
Visualization of Flow Patterns Induced by an Impinging Jet Issuing from a Circular Planform

1/N monotonically. The values of CL at the end of cycles 6-12 were 0.1867 (6), 0.2010 (7), 0.2072 (8), 0.2118 (9), 0.2148 (10), 0.2169 (11), and 0.2181 (12). Hence, the conclusion is that at these flow conditions the symmetric steady flow is unstable and that a slight perturbation will cause the flow to evolve to a nonsymmetric stable state. For this calculation the initial shock waves were located at 77% of the chord from the leading edge and the local Mach number just ahead of the shock was M= 1.172. During the course of the airfoil motion, the shock waves did not approach closer to the trailing edge than 92% chord location and the maximum local Mach number did not exceed 1.184. Therefore, the flow was consistent with the approximations of the unsteady transonic, small-disturbance theory used in LTRAN2. Also, the shock waves did not reach sufficiently close to the trailing edge that possible interference with the imposition of the Kutta condition might explain the anomalous flow. Multiple solutions have also been found for the transonic full potential steady flow, equation by Steinhoff and Jameson. Steinhoff and I will be investigating these anomalous computed flows further with the use of more complete governing equations. The motivation behind this effort is to determine whether the shock wave instability in these calculations also occurs in the Euler equations. If such an instability is found, it could provide an inviscid mechanism for invoking the buffet phenomenon, which also occurs over a narrow range of Mach numbers in the transonic regime.
Periodic variability in the optical counterpart of X-ray Nova Muscae 1991

Analysis of over 1000 CCD images of the optical counterpart of the black hole candidate Nova Muscae 1991, taken 3-5 months after the initial outburst, reveal the existence of a luminosity hump of about 0.2 mag which recurs every 10.5 hr. This period presumably either is, or is closely related to, the orbital period, which is thus similar to that of the confirmed black hole system A0620 - 00. The light-curve shape, the lack of significant color variations, and marginal evidence for a change in the recurrence period suggest that the luminosity humps in Nova Muscae may be related to the superhump phenomenon in the SU UMa subclass of dwarf novae. Other implications of the analogy between soft X-ray transients and dwarf novae are discussed.
Estimating Free-Riding Behavior: The StratAM Model

Spatial statistical methods in political science provide a tool to deal with spatial and other forms of interdependence in observational data. In this article, I derive a statistical model from a game of impure public goods provision. The resulting strategic autoregressive model (StratAM) allows the researcher to systematically explore the sources of free-riding behavior in the provision of public goods. The StratAM model is tightly related to the well-known spatial autoregressive (SAR) model and can be estimated in a maximum likelihood framework. I demonstrate the use of the StratAM model by analyzing free riding in the provision of foreign aid. Indicators of developmental needs and good governance strongly increase free-riding during the 1990s. Free-riding patterns in the 2000s are more similar to Cold War patterns.
Reentry Motion and Aerodynamics of the MUSES-C Sample Return Capsule

The Hayabusa spacecraft (MUSES-C) carries a small capsule for bringing asteroid samples back to the earth. The initial spin rate of the reentry capsule together with the flight path angle of the reentry trajectory is a key parameter for the aerodynamic motion during the reentry flight. The initial spin rate is given by the spin-release mechanism attached between the capsule and the mother spacecraft, and the flight path angle can be modified by adjusting the earth approach orbit. To determine the desired values of both parameters, the attitude motion during atmospheric flight must be clarified, and angles of attack at the maximum dynamic pressure and the parachute deployment must be assessed. In previous studies, to characterize the aerodynamic effects of the reentry capsule, several wind-tunnel tests were conducted using the ISAS high-speed flow test facilities. In addition to the ground test data, the aerodynamic properties in hypersonic flows were analyzed numerically. Moreover, these data were made more accurate using the results of balloon drop tests. This paper summarized the aerodynamic properties of the reentry capsule and simulates the attitude motion of the full-configuration capsule during atmospheric flight in three dimensions with six degrees of freedom. The results show the best conditions for the initial spin rates and flight path angles of the reentry trajectory.
Invention and Induction Laudan, Simon and the Logic of Discovery

Although on opposite sides of the logic of discovery debate, Laudan and Simon share a thesis of divorce between discovery (invention) and justification (appraisal); but unlike some other authors, they do not base their respective versions of the divorce-thesis on the empirical/logical distinction. Laudan argues that, in contemporary science, invention is irrelevant to appraisal, and that this irrelevance renders epistemically pointless the inventionist program. Simon uses his divorce-thesis to defend his account of invention, which he claims to be non-inductive--so evading the problem of induction. Underlying both authors' positions are inadequate conceptions of inductive inference. Laudan here ignores the role in contemporary science of plausibility arguments, which provide a crucial link between invention and appraisal, and thence an epistemic rationale for inventionism. Simon's account of invention does covertly call upon inductive principles from the context of appraisal, and this is what gives his program epistemic import; otherwise he would be vulnerable to Laudan's "no rationale" critique. The tensions in both authors reveal the falsity of the divorce-thesis, and the essential function of induction in both appraisal and invention of hypotheses.
Wolf-Rayet stars as starting points or as endpoints of the evolution of massive stars?

The paper investigates the evidence for the two interpretations of Wolf-Rayet stars suggested in the literature: (1) massive premain-sequence stars with disks and (2) massive stars which have lost most of their H-rich layers in a stellar wind is investigated. The abundance determinations which are done in two different ways and which lead to different conclusions are discussed. The composition is solar, which would suggest interpretation (1), or the CNO abundances are strongly anomalous, which would suggest interpretation (2). Results from evolutionary calculations, stellar statistics, the existence of Ofpe/WN9 transition stars and W-R stars with evolved companions show overwhelming evidence that W-R stars are not premain-sequence stars but that they are in a late stage of evolution. Moreover, the fact that W-R stars are usually in clear regions of space, whereas massive premain-sequence stars are embedded in ultracompact H II regions also shows that W-R stars are not young premain-sequence stars. 60 refs.
Experimental Study on Aerodynamic Characteristics of Telescopic Aerospikes with Multiple Disks

In this paper, experimental studies on telescopic aerospikes with multiple disks are reported. The telescopic aerospike is useful as an aerodynamic control device; however, changing its length causes a buzz phenomenon,which many researchers have reported. The occurrence of buzzing might be critical to the vehicle because it brings about severe pressure oscillations on the surface. Disks on the shaft produce stable recirculation regions by dividing the single separation flow into several conical cavity flows. Therefore, the telescopic aerospikes with stabilizer disks are useful without being any length constraints. Aerodynamic characteristics of the telescopic aerospikes were investigated using wind tunnel tests. Transition of recirculation/reattachment flow modes of a plain spike causes a large change in the drag coefficient. Because of this hysteresis phenomenon, the plain spike is unsuitable for fine aerodynamic control devices. Adding stabilizer disks is effective for the improved control of aerospikes.
Low-ionization active galactic nuclei: X-ray or shock heated?

We evaluate narrow-line ratios for a wide variety of active galactic nuclei, including those claimed to be shock heated. In the context of a Seyfert photoionization model, the entire range of observed narrow-line excitation conditions can be accounted for by varying a single parameter related to the photon flux. The characteristic (O I):(O II):(O III) line ratios which define Heckman's ''Liners'' are reproduced, obviating the need to invoke shock heating for these low-ionization nuclei, x-ray data on a number of Liners provide preliminary evidence for an ionizing continuum. The Seyfert 1.8 and 1.9 galaxies (weak, broad wings) appear to be transition cases between Seyferts and Liners. We conclude that Liners are low-luminosity or obscured Seyfert nuclei, or both. The photoionization model also explains the large (N II)/H.cap alpha. ratio often seen in the nuclei of galaxies.
Perceptual cues to English lexical stress: Comparison between native speakers and Mandarin second language learners.

The present study investigates the role of F0, duration, and vowel quality in English lexical stress perception by second language learners with a tonal L1. Mandarin speakers learning English as a second language (advanced learners, n=25; beginning learners n=25) were compared to a control group of native English speakers (n=25). Resynthesized disyllabic nonwords (dada) were presented in a stress localization task. Simultaneously manipulating five different F0 ratios (ratio of maximum fundamental frequency values of the first and second vowels) and five different duration ratios (ratio of duration values of the first and second vowels), stimuli were synthesized based on acoustic measurements from a previous study [Y. Lai and J. Sereno, J. Acoust. Soc. Am. 121, 3071 (2007)]. Both full‐vowel and reduced‐vowel stimuli were used. The results indicated that full vowels most often attracted stress across all three listener groups. More interesting, beginning second language listeners relied mainly on duration cues to determine the stressed syllables and advanced listeners focused more on F0 cues, while native listeners made use of both cues. The findings will be discussed in terms of the similarities and differences between the prosodic systems of Mandarin and English.
Signal-to-noise enhancement using delta modulation

A simple and novel method for improving the signal-to-noise ratio of repetitive signals is described. The circuit uses delta modulation and can achieve excellent times resolution. The signal-to-noise improvement ratio (SNIR) has been calculated for a few typical noise sources and experimental evidence to verify some of the calculated expressions is also presented.