Miracle-dz/UniFAR-FTUs huggingface dataset:
Residual-Based Rank Specification Tests for AR-GARCH Type Models

This paper derives the asymptotic distribution for a number of rank-based and classical residual specification tests in AR-GARCH type models. We consider tests for the null hypotheses of no linear and quadratic serial residual autocorrelation, residual symmetry, and no structural breaks. For these tests we show that, generally, no size correction is needed in the asymptotic test distribution when applied to AR-GARCH type residuals obtained through QMLE estimation. To be precise, we give exact expressions for the limiting null distribution of the test statistics applied to residuals, and find that standard critical values often lead to conservative tests. For this result, we give simple sufficient conditions. Simulations show that our asymptotic approximations work well for a large number of AR-GARCH models and parameter values. We also show that the rank-based tests often, though not always, have superior power properties over the classical tests, even if they are conservative. We thereby provide a useful extension to the econometrician's toolkit. An empirical application illustrates the relevance of these tests to the AR-GARCH models for the weekly stock market return indices of some major and emerging countries.
Method of source terms for dipole emission modification in modes of arbitrary planar structures

Modification of dipole emission that is due to its optical environment is calculated for planar layered structures. The layers are optically described by standard matrix techniques, and the dipole is included by using additive source terms for the electric field that depend on dipole orientation and wave polarization. These source terms also allow coupling through evanescent waves. We emphasize the applicability of this method to cases in which the power distribution into various modes is affected: dipole emission into guided modes and emission distribution into the various modes of structures that contain multilayer reflectors, such as microcavities.
Determinants of system transparency and its influence on trust in and reliance on unmanned robotic systems

Increasingly autonomous robotic systems are expected to play a vital role in aiding humans in complex and dangerous environments. It is unlikely, however, that such systems will be able to consistently operate with perfect reliability. Even less than 100% reliable systems can provide a significant benefit to humans, but this benefit will depend on a human operator’s ability to understand a robot’s behaviors and states. The notion of system transparency is examined as a vital aspect of robotic design, for maintaining humans’ trust in and reliance on increasingly automated platforms. System transparency is described as the degree to which a system’s action, or the intention of an action, is apparent to human operators and/or observers. While the physical designs of robotic systems have been demonstrated to greatly influence humans’ impressions of robots, determinants of transparency between humans and robots are not solely robot-centric. Our approach considers transparency as emergent property of the human–robot system. In this paper, we present insights from our interdisciplinary efforts to improve the transparency of teams made up of humans and unmanned robots. These near-futuristic teams are those in which robot agents will autonomously collaborate with humans to achieve task goals. This paper demonstrates how factors such as human–robot communication and human mental models regarding robots impact a human’s ability to recognize the actions or states of an automated system. Furthermore, we will discuss the implications of system transparency on other critical HRI factors such as situation awareness, operator workload, and perceptions of trust.
Measurement of Absorption Loss at 80 kHz Band for Wideband Underwater Acoustic Communication

To achieve high-speed acoustic data transmission, the use of a frequency band of 80±20 kHz is being considered. However, the absorption attenuation coefficient in these frequencies only has empirical formula. Therefore, the absorption attenuation was measured using the frequency of 60 to 100 kHz within the propagation distance of 250 to 510 m at a 1,000 m depth. The transmission signal wave form was measured with conductivity, temperature, and depth (CTD) data. From these measured data, the absorption attenuation coefficient was calculated using several empirical equations. As a result, a corresponding comparatively good for the empirical formula of Francois and Garrison.
Wavelet domain filtering for photon imaging systems

Many imaging systems rely on photon detection as the basis of image formation. One of the major sources of error in these systems is Poisson noise due to the quantum nature of the photon detection process. Unlike additive Gaussian noise, Poisson noise is signal-dependent, and consequently separating signal from noise is a very difficult task. In this paper, we develop a novel wavelet-domain filtering procedure for noise removal in photon imaging systems. The filter adapts to both the signal and the noise and balances the trade-off between noise removal and excessive smoothing of image details. Designed using the statistical method of cross-validation, the filter is simultaneously optimal in a small-sample predictive sum of squares sense and asymptotically optimal in the mean square error sense. The filtering procedure has a simple interpretation as a joint edge detection/estimation process. Moreover, we derive an efficient algorithm for performing the filtering that has the same order of complexity as the fast wavelet transform itself. The performance of the new filter is assessed with simulated data experiments and tested with actual nuclear medicine imagery.
Quantitative characterization of traumatic bruises by combined pulsed photothermal radiometry and diffuse reflectance spectroscopy

We apply diffuse reflectance spectroscopy (DRS) and pulsed photothermal radiometry (PPTR) for characterization of the bruise evolution process. While DRS provides information in a wide range of visible wavelengths, the PPTR enables extraction of detailed depth distribution and concentration profiles of selected absorbers (e.g. melanin, hemoglobin). In this study, we simulate experimental DRS spectra and PPTR signals using the Monte Carlo technique and focus on characterization of a suitable fitting approach for their analysis. We find inverse Monte Carlo to be superior to the diffusion approximation approach for the inverse analysis of DRS spectra. The analysis is then augmented with information obtainable by the fitting of the PPTR signal. We show that both techniques can be coupled in a combined fitting approach. The combining of two complementary techniques improves the robustness and accuracy of the inverse analysis, enabling a comprehensive quantitative characterization of the bruise evolution dynamics.
Magnetic Quenching of α and Diffusivity Tensors in Helical Turbulence

The effect of a dynamo-generated mean magnetic field of Beltrami type on the mean electromotive force is studied. In the absence of the mean magnetic field the turbulence is assumed to be homogeneous and isotropic, but it becomes inhomogeneous and anisotropic with this field. Using the test-field method the dependence of the α and turbulent diffusivity tensors on the magnetic Reynolds number ReM is determined for magnetic fields that have reached approximate equipartition with the velocity field. The tensor components are characterized by a pseudoscalar α and a scalar turbulent magnetic diffusivity ηt. Increasing ReM from 2 to 600 reduces ηt by a factor ≈5, suggesting that the quenching of ηt is, in contrast to the two-dimensional case, only weakly dependent on ReM. Over the same range of ReM, however, α is reduced by a factor ≈14, which can be explained by a corresponding increase of a magnetic contribution to the α-effect with opposite sign. Within this framework, the corresponding kinetic contribution to the α-effect turns out to be independent of ReM for 2 ⩽ ReM ⩽ 600. The level of fluctuations of α and ηt is only 10% and 20% of the respective kinematic reference values.
Confidence bands for hazard rates under random censorship

SUMMARY We suggest a completely empirical approach to the construction of confidence bands for hazard functions, based on smoothing the Nelsen-Aalen estimator. In particular, we introduce a local bandwidth-choice method. Our approach uses empirical information about both the survival rate and the censoring rate, and employs undersmoothing to alleviate difficulties caused by bias. We use both Edgeworth expansion and numerical simulation, the former to develop a basic formula and the latter to modify it for general use.
Estimation from a censored sample for the exponential family

SUMMARY The likelihood equations are derived for the estimation of the parameters of an exponential family from a Type I censored sample and are shown to have an interpretation which suggests a particular iterative method of solution. Some results relevant to the convergence properties of this method are given and the asymptotic variance-covariance matrix is derived. The method is illustrated by an example in which it is compared with an alternative method in the case of estimation for a doubly censored normal distribution.
Air Force electronic warfare evaluation simulator (AFEWES) infrared test and evaluation capabilities

The Air Force Electronic Warfare Evaluation Simulator (AFEWES) infrared countermeasures (IRCM) test facility currently has the ability to simulate a complete IRCM test environment, including IR missiles in flight, aircraft in flight, and various IR countermeasures including maneuvers, point-source flares, and lamp- and LASER-based jammer systems. The simulations of IR missiles in flight include missile seeker hardware mounted on a six degree-of-freedom flight simulation table. This paper will focus on recent developments and upgrades to the AFEWES IR capability. In particular, current developments in IR scene generation/projection and efforts to optically combine the IR image produced by a resistive array with existing foreground lamp sources.
Degenerate elliptical modes of a confocal cavity

It is shown that among degenerate modes of a confocal cavity there are field distributions which can be described as Gaussian beams of the elliptical type. These modes can be excited in cavities with elliptical or rectangular apertures, and they can be used to increase the efficiency and beam quality of the lasers with rectangular active elements. A numerical simulation is carried out for the Fresnel number N=1, stability in respect of possible cavity misalignments is demonstrated, and the losses per round trip are calculated for some of the lowest-order modes.
ON LIFTING TRANSFORMATION GROUPS

It is known [1] that if (X, G, IA) is a topological transformation group such that 7r1(G) = 0, and if X is a covering space of X, then there is a unique topological transformation group (5, G, ,) which covers (X, G, IA). In [2] the fundamental group o(X, xo, G) of a group of homeomorphisms G of a topological space X is defined,, and, it is observed in the proof of Theorem 7 of that paper that o-(X, xo, G) acts in a natural way as a group of homeomorphisms of the universal covering space X. In this note the relationship between these two results is investigated, and equations defining A are found. The language and notations will be minor modifications of those of [2], together with standard notations for covering spaces. It will be assumed throughout that X is path-connected, locally path-connected, and locally simply connected, that G is a locally pathconnected topological group, and that (X, G, IA) is a topological transformation group. First observe that every homeomorphism g of a path-connected space X induces an automorphism of the group N of normal subgroups of 7ri(X, xo). If k is a path from gx0 to xo, then the map [f]-4[kp+gf+k] is an automorphism of xri(X, x0). The image of a normal subgroup lro is a normal subgroup which is independent of k, and which will be denoted by g*iro. It is easily checked that g*: N-*N is an automorphism. DEFINITION 1. A normal subgroup ir0 of 7r,(X, x0) is said to be invariant under G if for every gEG, g*ro i=r0. Let [f; g]w, denote the equivalence class of the path f of order g under the equivalence relation
Surface strain measurement: a comparison of speckle shearing interferometry and optical fibre Bragg gratings with resistance foil strain gauges

The performance of two complementary optical strain measurement techniques, speckle shearing interferometry (shearography) and fibre Bragg grating (FBG) sensors, is compared with that of resistance foil strain gauges (RFSGs) and with theoretical predictions. The test object used for the surface strain measurements was a hydrostatically loaded ABS pipe. A multi-component shearography instrument, capable of full surface strain measurement, was used to determine the displacement gradient components, from which the surface strain components were calculated. Six surface mounted wavelength division multiplexed FBG sensors were used to measure the axial and the hoop strains. RFSGs located on the surface of the pipe, adjacent to the FBGs, were used for comparison. Reasonable agreement between theory and the axial and hoop strains determined by the different techniques was found. Issues associated with deploying and comparing the techniques are discussed.
A test for conditional heteroskedasticity in time series models

When testing for conditional heteroskedasticity and nonlinearity, the power of the test in general depends on the functional forms of conditional heteroskedasticity and nonlinearity that are allowed under the alternative hypothesis. We suggest a test for conditional heteroskedasticity and nonlinearity with the nonlinear autoregressive conditional heteroskedasticity model of Higgins and Bera as the alternative. Standard testing procedures are not applicable since our nonlinear autoregressive conditional heteroskedasticity (ARCH) parameter is not identified under the null hypothesis. To resolve this problem, we apply the procedure recently proposed by Davies. Power and size of the suggested test are investigated through simulation, and an empirical application of testing for ARCH in exchange rates is also discussed.
Influence of the spatial pump distribution on the performance of high power vertical-external-cavity surface-emitting lasers

The performance of a 1040 nm vertical-external-cavity surface-emitting laser is studied as function of the size and shape of the pumped area. The input-output characteristics of the device are monitored while simultaneously tracking the temperature in the active region. It is shown that the pump spot shape plays a crucial role in optimizing the laser output. Improvements up to a factor of 5 are found for a super-Gaussian in comparison to the standard Gaussian shape. For the large pump-spot sizes needed for high output powers, it turns out that the power-scalability breaks down due to the suppressed lateral heat flow.
Automatic 3D point clouds registration method

3D point clouds registration is a crucial problem in reverse engineering. In order to register point clouds without manual information on objects, a novel method is proposed based on geometric properties of point clouds. The method consists four parts: selecting public areas, computing normal vectors and curvatures, finding corresponding points and further precise registration. Public areas of point clouds are selected through a scan order method. Normal vector and curvature of each point are calculated through surface fitting. Curvatures of points are taken as the registration relationship and all the pair-wise points with the same or similar curvature are extracted. The property of distance invariance in rigid body transformation is used to match the pair-wise points. Matching points are picked out and mismatched ones are excluded by comparing the curvatures in the k-neighborhood. After that the algorithm of quaternion is used to compute transform matrix and ICP algorithm is introduced to improve registration precision. Experimental results show that the proposed method is robust when registering point clouds of different scans.
A Numerical Simulation of Wintertime, Orographic Precipitation: Part I. Description of Model Microphysics and Numerical Techniques

Abstract A numerical model which extends treatment of microphysical cloud processes to more than one level through use of the continuous bin technique is described. A general solution to the diffusion growth equation including latent heat release due to accretion is presented. Collection processes of coalescence, accretion and aggregation, activation of CCN, and ice phase nucleation through sorption and contact freezing nucleation are combined with a diffusion treatment which allows for calculation of the supersaturation in a multi-level framework and with sedimentation of particles between levels.
Revival of the magnetoelectric effect

Recent research activities on the linear magnetoelectric (ME) effect—induction of magnetization by an electric field or of polarization by a magnetic field—are reviewed. Beginning with a brief summary of the history of the ME effect since its prediction in 1894, the paper focuses on the present revival of the effect. Two major sources for ‘large’ ME effects are identified. (i) In composite materials the ME effect is generated as a product property of a magnetostrictive and a piezoelectric compound. A linear ME polarization is induced by a weak ac magnetic field oscillating in the presence of a strong dc bias field. The ME effect is large if the ME coefficient coupling the magnetic and electric fields is large. Experiments on sintered granular composites and on laminated layers of the constituents as well as theories on the interaction between the constituents are described. In the vicinity of electromechanical resonances a ME voltage coefficient of up to 90 V cm−1 Oe−1 is achieved, which exceeds the ME response of single-phase compounds by 3–5 orders of magnitude. Microwave devices, sensors, transducers and heterogeneous read/write devices are among the suggested technical implementations of the composite ME effect. (ii) In multiferroics the internal magnetic and/or electric fields are enhanced by the presence of multiple long-range ordering. The ME effect is strong enough to trigger magnetic or electrical phase transitions. ME effects in multiferroics are thus ‘large’ if the corresponding contribution to the free energy is large. Clamped ME switching of electrical and magnetic domains, ferroelectric reorientation induced by applied magnetic fields and induction of ferromagnetic ordering in applied electric fields were observed. Mechanisms favouring multiferroicity are summarized, and multiferroics in reduced dimensions are discussed. In addition to composites and multiferroics, novel and exotic manifestations of ME behaviour are investigated. This includes (i) optical second harmonic generation as a tool to study magnetic, electrical and ME properties in one setup and with access to domain structures; (ii) ME effects in colossal magnetoresistive manganites, superconductors and phosphates of the LiMPO4 type; (iii) the concept of the toroidal moment as manifestation of a ME dipole moment; (iv) pronounced ME effects in photonic crystals with a possibility of electromagnetic unidirectionality. The review concludes with a summary and an outlook to the future development of magnetoelectrics research.
Hygrothermal Stresses in Unsymmetric Laminates Disturbed by Elliptical Holes

Since the composite laminates are now in widespread use, many coupling phenomena within the composite laminates are widely focused in the world. One of those is the problem of stretching-bending coupling under hygrothermal environment. Because of the hygrothermal stress concentration, the understanding of hygrothermal effects on holes in laminates becomes important for the practical engineering design. However, due to mathematical infeasibility, most of the analytical solutions presented in literature are for two-dimensional problems or just for mechanical loading conditions, not for general composite laminates under hygrothermal environment. In order to establish a systematic analytical approach, in this study by extending the Stroh formalism for two-dimensional linear anisotropic elasticity and the Stroh-like formalism for coupled stretching-bending analysis of composite laminates, we develop an extended Stroh-like formalism for the coupled stretching-bending analysis under hygrothermal environment. By using the extended Stroh-like formalism developed in this paper, the explicit solutions for an unbounded laminate, symmetric or unsymmetric, disturbed by an elliptical hole subjected to uniform heat flow and moisture transfer in the x 1 -x 2 plane or x 3 direction are now obtained. With these solutions three typical numerical examples are illustrated and compared by ANSYS finite element software package.
On the solution of time-harmonic scattering problems for Maxwell's equations

This paper deals with the scattering of a monochromatic electromagnetic wave by a perfect conductor surrounded by a locally inhomogeneous medium. The direct numerical solution of this problem by a finite-element method requires special edge elements. The aim of the present paper is to give an equivalent formulation of the problem well suited for both easy theoretical investigation and numerical implementation. Following a well-known idea, this formulation is obtained by adding a regularizing term such as “grad div” in the time-harmonic Maxwell equations, which leads us to solve an elliptic problem similar to the vector Helmholtz equation instead of Maxwell’s equation. The numerical treatment of this new formulation requires only standard Lagrange finite elements.A unified approach, which is valid for the equations satisfied by either the electric or the magnetic field, is presented. It applies for a conductor with a Lipschitz-continuous boundary surrounded by a dissipative or nondissipative medium whose e.
Engineering photon cascades from multiexciton complexes in a self-assembled quantum dot by a lateral electric field

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Effect of Wall Roughness on the Slip of Fluid in a Microchannel

The molecular dynamics simulation of fluid flow through a two-dimensional microchannel channel with atomically rough walls is reported. The roughening elements distributed on the surface of solid walls were modeled by atomic modules with specified amplitude and periodicity. The effect of various parameters such as wall energetic, amplitude, periodicity, and topology of roughening elements on the slip of fluid is investigated. The results indicate that the Knudsen number is not the sole parameter identifying the slip condition at the walls when the amplitude of surface roughness is comparable with the molecular mean free path. It was also found that the topology and number of roughening arrays can influence the slip of fluid at solid surface. The adsorption of wall does not show any significant effect on the slip in rough channel. However, it plays an important role on the amount of slip in smooth channel.