Miracle-dz/UniFAR-FTUs huggingface dataset:
A novel recursive subspace identification approach of closed-loop systems

In this paper, a subspace model identification method under closed-loop experimental condition is presented which can be implemented to recursively identify and update the system model. The projected matrices play an important role in this identification scheme which can be obtained by the projection of the input and output data onto the space of exogenous inputs and recursively updated through sliding window technique. The propagator type method in array signal processing is then applied to calculate the subspace spanned by the column vectors of the extended observability matrix without singular value decomposition. The speed of convergence of the proposed method is mainly dependent on the number of block Hankel matrix rows and the initialization accuracy of the projected data matrices. The proposed method is feasible for the closed-loop system contaminated with coloured noises. Two numerical examples show the effectiveness of the proposed algorithm.
The X-ray properties of high-redshift quasi-stellar objects

Sensitive X-ray information is presented for about 90 previously uncataloged high-redshift, optically selected QSOs. Two high-redshift subsets of this larger data base are emphasized: (1) a 'complete' sample of 37 objects with z = 1.8 - 3.0, and B of 19.5 or less and (2) a sample of 78 QSOs that span a narrow range in redshift and optical luminosity. From the complete sample, it is inferred that such QSOs contribute less than 3 percent to the diffuse X-ray background (XRB), and that the contribution of all QSOs with B of 19.5 or less to the XRB is 21 + or - 8 percent. For the narrow sample, it is found that the mean X-ray to optical luminosity ratio is characterized by alpha(eff)ox = 1.50 + or - 0.03. A variety of new, model-independent, empirical evidence is presented that the primary dependence of alpha(ox) is on optical luminosity rather than redshift. It is concluded that QSOs can supply as much as 70 percent of the XRB, with the typical contributor a moderate redshift QSO with B of roughly 19-21.
Multi-Line Observations of Molecular Gas in the Central Region of the Low Star-Formation Efficiency “Starburst” Galaxy NGC 4527

We performed high-resolution CO(J = 2–1), CO(J =1 –0), HCN(J = 1–0), HCO + (J = 1–0), and 3mm continuum observations of the low star formation efficiency (SFE) “starburst” galaxy NGC 4527 with the Nobeyama Millimeter Array. From CO(J =1–0) observations, wefound two offsetridges with non-circular motion and acentral gas concentration. The distribution and kinematics of NGC 4527 are very similar to those of barred spiral galaxies. The distribution of CO(J = 2–1) emission resembles the features of the concentrated component of CO(J = 1–0). HCN(J = 1–0) and HCO + (J = 1–0) emissions concentrated toward the center have also been detected. The total mass of molecular gas detected in the central r< 30 �� is 2.5 ×10 9 M� . T he HCN(J = 1–0)/CO(J = 1–0) integrated intensity ratio of 0.075 ±0.008 in the central r 3 �� –4 �� region of NGC 4527 could suggest that the fraction of dense molecular gas to the total molecular gas is small compared with those of prototypical starburst galaxies, such as NGC 253. This suggests that the small dense gas fraction is responsible for the low SFE in the center of NGC 4527, though this interpretation could depend on aperture sizes of the observations. The ratio of the dynamical mass to molecular gas mass is 13% within the central region ( r< 500pc). This suggests that molecular gas within the r< 500pc region could be in a state of gravitational instability. The low SFE, the small dense gas fraction, and the large amount of gravitationally unstable molecular gas can be explained if NGC 4527 is in the very early phase of starburst phenomena or a pre-starburst phase, and the formation of dense molecular gas will begin and the SFE will increase within a short time scale.
Ultrasonic force microscopy for nanometer resolution subsurface imaging

We present a novel method for nanometer resolution subsurface imaging. When a sample of atomic force microscope (AFM) is vertically vibrated at ultrasonic frequencies much higher than the cantilever resonance, the tip cannot vibrate but it is cyclically indented into the sample. By modulating the amplitude of ultrasonic vibration, subsurface features are imaged from the cantilever deflection vibration at the modulation frequency. By adding low‐frequency lateral vibration to the ultrasonic vibration, subsurface features with different shear rigidity are imaged from the torsional vibration of cantilever. Thus controlling the direction of vibration forces, we can discriminate subsurface features of different elastic properties.
Network characteristics of individual pigments in cyanobacterial photosystem II core complexes

Part of the excitation energy transfer (EET) characteristics of the photosystem II (PSII) comes from the interconnection between pigments. To understand the correlation between the EET and the pigments’ interaction structure, we construct a network from the EET rates which are related to both the distance between the pigments (chlorophylls and pheophytins) and their spatial orientations. Especially, we investigate how well the PS II core complex’s EET functionality can be explained by using only the network topology in Thermosynechococcus vulcanus 1.9 °A. Starting from the Förster theory, we construct a network of EET pathways. For an analysis of the network structure, we calculate common network-structural measures like betweenness centrality, eigenvector centrality and weighted clustering. These measures can reflect the role of individual pigments in the EET network. In our work, we found that some well-known properties were reproduced by the network analysis of the simplified network, which means that the topology of the network encodes functionally relevant information. For example, from the network structural analysis, we can infer that most of the chlorophyll molecules (clorophylls) in the pigment-protein complex CP47 have heightened probability to transfer energy compared with other chlorophylls. We also see that the active branch chlorophylls in the reaction center are characterized by a high eigenvector centrality, a high betweenness centrality and a low weighted clustering coefficient. This is indicative of functionally important vertices.
Structured IR illumination for relative depth sensing in virtual interfaces

Depth mapping or depth sensing has become a popular field, applied not only to automotive sensing for collision avoidance (radar) but also to gesture sensing for gaming and virtual interfaces (optical). Popular gesture sensing devices such as the Kinect from Microsoft's Xbox gaming device produce a full absolute depth map, which is in most cases not adapted to the task on hand (relative gesture sensing). We propose in this paper a new gesture sensing technique through structured IR illumination to provide a relative depth mapping rather than an absolute one, and this reducing the requirements on computing power and therefore enabling this technology for wearable computing such as see through display.
Causality in Plasma Electrodynamics

Causality in electrodynamics is reviewed in regard to the interrelations among the causal requirement, the analyticity of the dielectric permittivity, and the Kramers-Kronig relations. We show that the collisionless damping (Landau damping) of a plasma wave can be formally derived from the causal requirement imposed on the susceptibility of a Vlasov-Poisson plasma. Here, the causal requirement is that the susceptibility χ(t) be nil for t < 0, which means the future electric field has nothing to do with the response effected in the medium at the present time. We show that this single requirement provides the analyticity of χ(ω) in the upper half-ω plane, the Kramers- Kronig relations, and Landau damping. Cerenkov emission which is the inverse process of Landau damping is also discussed in the light of causality. We present an easy way to calculate the electric fluctuation in a magnetized plasma by regarding a plasma as an assembly of non-interacting cold beams. We investigate the case of a separable distribution function g(x,t,v)=g˜(v)f(x−v0t)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$g(x,t,v) = \tilde g(v)f(x - {v_0}t)$$\end{document}, which corresponds to a special type of Benstein-Greene-Kruskal wave and a slight generalization of Van Kampen’s distribution function. We review Van Kampen’s theory of a Vlasov-Poisson system, which corresponds to the Sturm-Liouville theory of differential equations, and show that the Vlasov- Poisson equations in this separable case are trivially solved in terms of the separation constant. It is philosophically interesting that the collisionless damping of a plasma wave can be attributed to causality, which defines the direction of time and is operative in general electrodynamics.
Kinematics and Composition of H II Regions in Spiral Galaxies. II. M51, M101, aND NGC 2403

The velocities of H II regions in M101 and NGC 2403 and the excitations, log(forbidden O III/H-beta), in regions in M101, M51, and NGC 2043 were measured using the MX multiobject spectrometer. The velocity data are used to determine position angles, inclinations, rotation curves, line-of-sight velocity dispersion, and mass-to-light ratios for the optical disks of NGC 2403 and M101. The excitation data are used to examine the differences between galaxies. It is shown that late-type spiral galaxies may be divided into two distinct groups on the basis of excitation of their H II regions at a particular fractional radius. It is found that the excitation gradients of M33 and M101 steepen significantly toward the center of the galaxy. The excitation measurements are used to estimate the magnitude of the abundance gradients in M33, M101, NGC 2403, and NGC 2997. 46 refs.
H∞ filtering of network-based systems with communication constraints

This work studies the H∞ filtering problem for a class of discrete-time network-based systems with communication constraints. The considered plant has multiple outputs and only one of them can be sent to the filter at each transmission instant because of the communication constraints. A new compensation scheme is proposed, upon which the filtering error system is modelled as a switched system by considering mode-dependent filters. Sufficient conditions are derived for the filtering error system to be exponentially stable and ensure a prescribed H∞ disturbance attenuation level bound by using the average dwell-time method. Based on the derived conditions, a design procedure for the H∞ filter is also presented. An illustrative example is given to show the effectiveness of the proposed method.
Quantitative nuclear magnetic resonance measurements of preasymptotic dispersion in flow through porous media

We use pulsed field gradient nuclear magnetic resonance to probe molecular displacements in preasymptotic Stokes flow through a pack of beads with bead diameter d=100±20μm, through a Bentheimer sandstone, and a Portland carbonate rock core, for a common range of flow velocities v and interrogation times Δ. For flow through the bead pack the length scale of the pore is well defined, as are the Peclet number Pe∊[20–80] and the Reynolds number Re<0.1. Probability distributions of molecular displacements P(ζ) are determined. The mean displacement ⟨ζ⟩, the variance σ2≡⟨(ζ−⟨ζ⟩)2⟩ and the skewness γ3≡⟨(ζ−⟨ζ⟩)3⟩ of P(ζ) are determined by a self-consistent cumulant analysis designed to minimize the systematic errors to which any cumulant analysis of non-Gaussian distributions is susceptible. Systematic errors in σ and γ arising from surface relaxation effects and flow displacements through the internal fields of rocks are quantified.
Entropy analysis in foreign exchange markets and economic crisis

We investigate the relative market efficiency in 11 foreign exchange markets by using the Lempel-Ziv (LZ) complexity algorithm and several entropy values such as the Shannon entropy, the approximate entropy, and the sample entropy. With daily data in 11 foreign exchange markets from Jan. 2000 to Sep. 2011, we observe that mature markets have higher LZ complexities and entropy values than emerging markets. Furthermore, with sliding time windows, we also investigate the temporal evolutions of those entropies from Jan. 1994 to Sep. 2011, and we find that, after an economic crisis, the approximate entropy and the sample entropy of mature markets such as Japan, Europe and the United Kingdom suddenly become lower.
Holographic Dark Energy and Quantum Entanglement

In this paper, we briefly review the holographic dark energy model and introduce the idea that dark energy is a kind of thermal energy related to the quantum entanglement of the vacuum across a cosmic future event horizon. The holographic dark energy model comes from a theoretical attempt to apply the holographic principle to the dark energy problem and follows the idea that the short distance cut-off or ultraviolet (UV) cut-off is related to the long distance cut-off or infrared (IR) cut-off. The IR cut-off relevant to dark energy is the size of the future event horizon. This model gives a holographic dark energy comparable to the observational data. Though this model is in good agreement with observational data, some problems (non-locality, circular logic, causality problem, etc.) exist due to the use of the future event horizon as a present IR cut-off. These problems of the holographic dark energy model are considerably resolved using action principle and equations of motion. Finally, we discuss the relation between quantum entanglement and dark energy which is connected to the more fundamental relation between entanglement and gravity.
Improving handoff QoS with or without mobility prediction

Mobility prediction techniques have been proposed to improve handoff performance by reserving bandwidth in the cells traversed by the predicted trajectory of a mobile terminal. These techniques generally involve intensive computations in achieving accurate prediction. It is investigated whether it is worthwhile to deploy such computationally intensive techniques by evaluating the impact of mobility prediction accuracy on the performance improvement in handoff calls.
Boundary-Layer Heat Transfer from a Stretching Circular Cylinder in a Nanofluid

DB = Brownian diffusion coefficient DT = thermophoretic diffusion coefficient f = reduced stream function g = gravitational acceleration K = permeability of porous medium km = effective thermal conductivity Le = Lewis number Nb = Brownian motion parameters Nt = thermophoresis parameters Nu = Nusselt number p = pressure q = wall heat flux Re = Reynolds number r; z = Cartesian coordinates S = shear stress T = temperature Tw = wall temperature of the vertical plate T1 = ambient temperature u, w = Darcy velocity components m = thermal diffusivity of porous medium = dimensionless distance = dimensionless temperature = viscosity of fluid = kinematic viscosity f = fluid density p = nanoparticle mass density c f = heat capacity of the fluid c m = effective heat capacity c p = effective heat capacity of nanoparticle material = ratio between the effective heat capacity of the nanoparticle material and that of the fluid Subscripts
Simple formulation of turbulent mixing in the stable free atmosphere and nocturnal boundary layer

Turbulent mixing lengths and the eddy Prandtl number are estimated by analyzing aircraft data from three different field programs and existing studies in the literature. For small scale turbulence, the estimated mixing lengths appear to decrease rapidly with increasing Richardson number (Ri) and then reach an approximately constant value of 2.5 m for Ri > 0.3 with large scatter. A least squares fit of the estimated mixing length for heat using the format of Louis et al. (1981) yields an asymptotic mixing length of 14.2 m for neutral stratification. This value represents the best fit to the turbulent fluxes for the observed cases of stratified flow rather than a direct calibration of turbulence in neutrally stratified flow for which there were no observations. Mixing length values estimated from stronger larger scale disturbances also show a decrease of mixing length with increasing Richardson number although the values of mixing lengths are categorically larger yielding an asymptotic value of 150 m. Apparently, the Richardson number by itself is not a good predictor for the strength of turbulent mixing although suitable alternatives for large scale models are not available. The Prandtl number increases with increasing Richardson number in agreement with previous studies but the scatter is large. The mixing length formulation is applied to a column model of the lower troposphere. The asymptotic mixing length and the stability-dependent Prandtl number are derived from the data analysis. For the very stable case, shear generation of turbulence in the upper part of the surface inversion layer can be more significant than surface based turbulence generation. Large scale subsidence may significantly reduce the depth of the overlying residual layer. Since the subsidence is difficult to estimate from observations, model comparisons with the observed data are not conclusive. DOI: 10.1034/j.1600-0870.1992. t01-4-00003.x
Electrical conductivity of a nondegenerate electron gas with a complex shaped quantum well

In this paper, the electrical conductivity of a nondegenerate electron gas with a complex shaped quantum well is calculated. The conductivity’s dependences on the temperature and on the parameters of the quantum well are studied in the case of electron-phonon scattering. For scattering of electrons by polar optical phonons, the conductivity is shown to depend essentially on the temperature, as distinct from acoustical phonon scattering and to decrease with increasing temperature. Also, the conductivity decreases down to zero, with increasing potential of quantum well.
Construction of exact Ermakov-Pinney solutions and time-dependent quantum oscillators

The harmonic oscillator with a time-dependent frequency has a family of linear quantum invariants for the time-dependent Schrödinger equation, which are determined by any two independent solutions to the classical equation of motion. Ermakov and Pinney have shown that a general solution to the time-dependent oscillator with an inverse cubic term can be expressed in terms of two independent solutions to the time-dependent oscillator. We explore the connection between linear quantum invariants and the Ermakov-Pinney solution for the time-dependent harmonic oscillator. We advance a novel method to construct Ermakov-Pinney solutions to a class of time-dependent oscillators and the wave functions for the time-dependent Schrödinger equation. We further show that the first and the second Pöschl-Teller potentials belong to a special class of exact time-dependent oscillators. A perturbation method is proposed for any slowly-varying time-dependent frequency.
On the h- and p-Versions of the Extrapolated Gordon's Projector with Applications to Elliptic Equations

This paper outlines a new application of Cordon's blending technique for the finite element approximation of elliptic boundary value problems. The algebraic structure of the discrete blended interpolation projector with its first- (or coarse-) and second- (or fine-) discretization levels suggests making linear combinations of independent calculations. For the interpolation of smooth data, each of the separate calculations yields a low-order result while their combination gives a high-order result. It is conjectured that this property holds for the approximation of regular boundary value problems (BVPs). The algorithm might therefore be viewed as an extrapolation procedure. Two different versions of the algorithm are proposed, which relate to the so-called h- and p-versions of finite element approximations. The computational complexities compare favorably with classical schemes. The implementation on parallel computers is discussed. Numerical results for some bivariate problems (both regular and singular) are presented. They indicate that for smooth problems, the algorithms behave as expected.
Upconversion in Er-implanted Al2O3 waveguides

When pumped with a 1.48 μm laser diode, Er‐implanted Al2O3 ridge waveguides emit a broad spectrum consisting of several distinct peaks having wavelengths ranging from the midinfrared (1.53 μm) to the visible (520 nm). In order to explain these observations, three different upconversion mechanisms are considered: cooperative upconversion, excited state absorption, and pair‐induced quenching. It is found that for samples with a high Er concentration (1.4 at. %), cooperative upconversion completely dominates the deexcitation of the Er3+ ions. For a much lower concentration (0.12 at. %), the influence of cooperative upconversion is strongly reduced, and another upconversion effect becomes apparent: excited state absorption. These conclusions are based on measurements of the luminescence emission versus pump intensity, and also on measured luminescence decay curves. The upconversion coefficient is found to be (4±1)×10−18 cm3/s; the excited state absorption cross section is (0.9±0.3)×10−21 cm2. It is shown that in spite of these upconversion effects, a high fraction of the Er3+ can be excited at low pump powers. For pump powers between 2 and 10 mW, the optimum Er concentration is calculated. The results show that for an Er concentration of 0.5 at. %, more than 2 dB/cm net optical gain is achievable at a pump power less than 10 mW.
Erosion of Tungsten Coated Tiles on the Central Column of ASDEX Upgrade

There are plans at ASDEX Upgrade to cover the heat shield of the inner main chamber wall with tungsten coated graphite tiles. Four tiles were installed at different poloidal positions of the heat shield and removed after a full experimental campaign. The tiles were analysed by means of Rutherford backscattering (RBS) analysis before insertion and by both RBS and particle induced X ray emission after removal. This is an investigation of the poloidal and toroidal erosion profiles on the tiles due to sputtering by charge exchange neutral and ion impact.
Hubble Space Telescope imaging of super-star clusters in NGC 1569 and NGC 1705

We examine the structural properties of three super-star clusters in the nearby, H I-rich galaxies NGC 1569 and NGC 1705. The clusters, which have total absolute V magnitudes between -13.3 and -14.1, appear to be point sources on ground-based images but are partially resolved in new images obtained with the Hubble Space Telescope (HST) Planetary Camera. From deconvolved V- and I-band images we find that the three clusters have very compact cores with extended halos that are partially resolved into individual stars. Using new distances to the galaxies derived from color-magnitude diagrams for field stars, we find that the half-light radii are 2.2-3.4 pc. The cluster in NGC 1705 is barely resolved in the HST images. The clusters in NGC 1569, on the other hand, show significant substructure in their cores and ellipticities that are comparable to the flattenings seen in young clusters in the Large Magellanic Cloud (LMC). The clusters show internal (V-I) color gradients. The properties of these clusters are similar to R136, the core of the luminous star-forming complex 30 Doradus in the LMC, except that R136 has a lower luminosity and central surface brightness. The half-light surface brightness of the brightest cluster (NGC 1569 A) is 1.3 x 10(exp 6) L(sub v) solar/ sq cm, which is over 65 times higher than R136 and 1200 times higher than the mean rich LMC star cluster other than R136 after allowing for aging effects. The next brightest clusters in each of these galaxies are greater than or = 2 mag fainter. Thus, the super-star clusters represent an extreme but uncommon mode of star formation. In terms of luminosity and size, they appear to be good analogs of young globular clusters.