Miracle-dz/UniFAR-FTUs huggingface dataset:
Learning Condition-Invariant Scene Representations for Place Recognition across the Seasons Using Auto-Encoder and ICA

To localize the position and perfect autonomous navigation, building up a map is essential for mobile robots. The map becomes very important when the weather is not appropriate for the robot. However, the map becomes inconsistent when the robot moves in the environment and detects errors with emotional accuracy. The loop-closure detection is the process through which a robot can acknowledge the location visited previously, which can identify the ultimate solution to the previous problem. The robot faced difficulty identifying its previously visited path when the environment underwent an extreme change. The main motive of our work is to promote a model capable of understanding the scenes that are presented robustly. Moreover, during seasonal changes, this model provides an appropriate loop-closure detection result. Independent component analysis (ICA) and auto-encoder are proposed to complete our research work. ICA is a powerful tool to describe invariant images perfectly. Especially, when the robot moves through a changing environment, ICA provided more accurate outcomes than the other algorithm (baseline algorithm). On the other hand, the auto-encoder can distinguish between two features of scene variant condition and invariant condition. The encoder takes our work’s next steps by discovering possible routes. To analyze the performance, this work uses the baseline method with a precision-recall curve and a fraction of correct matches. The proposed algorithm ICA showed a 91.05% accuracy rate, which is better than the baseline algorithms, and the appropriate route-finding rate using an auto-encoder is also acceptable.
Alternative robust servo-control system and its digital control

An alternative approach to the design of a servomechanism for a continuous system is presented and its digital control is considered. The proposed design of the digital control system is based on the quadratic criterion function for a continuous system, and a smooth control input is given as the output of a high-order sample-hold circuit, which is derived from the characteristics of the reference signal and disturbances.
LED solution for E14 candle lamp

On a short to medium term, energy efficient retrofit LED products can offer an attractive solution for traditional lamps replacement in existing fixtures. To comply with user expectations, LED retrofit lamps should not only have the same mechanical interface to fit (socket and shape), but also have the similar light effect as the lamps they replace. The decorative lighting segment shows the best conditions to meet these requirements on short term. In 2008, Philips Lighting Shanghai started with the development of an LED candle lamp for the replacement of a 15W Candle shape (B35 E14) incandescent bulb, which is used in e.g. chandeliers. In this decorative application the main objective is not to generate as much light as possible, but the application requires the lamp to have a comparable look and, primarily, the same light effect as the incandescent candle lamp. This effect can be described as sparkling light, and it has to be directed sufficiently downwards (i.e., in the direction of the base of the lamp). These requirements leave very limited room for optics, electronics, mechanics and thermal design to play with in the small outline of this lamp. The main voltage AC LED concept is chosen to save the space for driver electronics. However the size of the AC LED is relatively big, which makes the optical design challenging. Several optical solutions to achieve the required light effect, to improve the optical efficiency, and to simplify the system are discussed. A novel prismatic lens has been developed which is capable of transforming the Lambertian light emission from typical high power LEDs into a butter-fly intensity distribution with the desired sparkling light effect. Thanks to this lens no reflecting chamber is needed, which improves the optical efficiency up to 70%, while maintaining the compact feature of the original optics. Together with advanced driver solution and thermal solution, the resulting LED candle lamp operates at 230V, consumes 1.8W, and delivers about 55 lm at 3000K with the requested radiation pattern and sparkle effect. Some field tests were done with positive feedback.
Carbon monoxide in the starburst of NGC 253 revisited

We present sensitive measurements of 12CO, 13CO and C18O in the J=1 0, 2 1 and 3 2 lines, and C17O in the J=1 0 and 2 1 lines towards the nucleus of the starburst galaxy NGC 253. Our C18O measurements are consistent with those reported by Harrison et al., but our 13CO J=32 measurement is inconsistent with that of Wall et al. The resulting similarity between the 13CO J=32/J=21 and C18O J=32/J=21 integrated line intensity ratios indicates that there is little or no evidence for isotope-selective photodissociation of CO in NGC 253, that 13CO is co-existent with C18O in the central 23 arcsec (300 pc) of the galaxy, and that the relative abundances of various CO isotopomers can be derived. We have determined the isotopic ratios of oxygen towards the centre of NGC 253. We find the 16O/18O ratio to be ∼ 150 and the 18O/17O ratio to be ∼ 6.5. The latter value confirms the results of Sage, Mauersberger & Henkel, and requires that the interstellar medium (ISM) in the core of NGC 253 is substantially enriched by the ejecta from massive stars. We derive 3.5±1.5 × 1018 cm−2 as the beam-averaged column density of CO in the central 23 arcsec. The beam filling factor of CO is ∼ 0.1. This indicates that the average C/CO abundance ratio is 1.4±0.7 in this region. We use measurements of the principal gas-phase sinks of carbon to determine that 2.5×107 M⊙ is the mass of the ISM within this region. This is consistent with the results of Mauersberger et al., implying that the X=N(H2)/I(CO) conversion factor in NGC 253 is < 20 per cent of the value determined for the disc of the Milky Way. Our measurements also highlight that there is a radial fall-off in the average molecular gas density in NGC 253, in agreement with that reported by Wall et al. The isophotes of our 12CO data show a radial change in ellipticity. Such a change is consistent with the existence of barred orbits in NGC 253, recently postulated by Peng et al.
New vision system and navigation algorithm for an autonomous ground vehicle

Improvements were made to the intelligence algorithms of an autonomously operating ground vehicle, Q, which competed in the 2013 Intelligent Ground Vehicle Competition (IGVC). The IGVC required the vehicle to first navigate between two white lines on a grassy obstacle course, then pass through eight GPS waypoints, and pass through a final obstacle field. Modifications to Q included a new vision system with a more effective image processing algorithm for white line extraction. The path-planning algorithm adopted the vision system, creating smoother, more reliable navigation. With these improvements, Q successfully completed the basic autonomous navigation challenge, finishing tenth out of over 50 teams.
Resistance inequalities for the isotropic Heisenberg ferromagnet

Inequalities concerning the spin correlations of states of finite energy of the isotropic ferromagnetic Heisenberg model are proved. These inequalities estimate the spin correlation between two lattice sites in terms of the total energy and the electrical resistance between the lattice sites as calculated using the inverse of the coefficients occurring in the Heisenberg Hamiltonian. These resistance inequalities are combined with the resistance properties of a regular three‐dimensional lattice to yield the result that all states of finite energy for the isotropic Heisenberg model in three dimensions have long range order.
Sensitivity of Goodness of Fit Indexes to Lack of Measurement Invariance

Two Monte Carlo studies were conducted to examine the sensitivity of goodness of fit indexes to lack of measurement invariance at 3 commonly tested levels: factor loadings, intercepts, and residual variances. Standardized root mean square residual (SRMR) appears to be more sensitive to lack of invariance in factor loadings than in intercepts or residual variances. Comparative fit index (CFI) and root mean square error of approximation (RMSEA) appear to be equally sensitive to all 3 types of lack of invariance. The most intriguing finding is that changes in fit statistics are affected by the interaction between the pattern of invariance and the proportion of invariant items: when the pattern of lack of invariance is uniform, the relation is nonmonotonic, whereas when the pattern of lack of invariance is mixed, the relation is monotonic. Unequal sample sizes affect changes across all 3 levels of invariance: Changes are bigger when sample sizes are equal rather than when they are unequal. Cutoff points for testing invariance at different levels are recommended.
The Optimal GAN Discriminators are High-dimensional Interpolators

We consider the problem of optimizing the discriminator in generative adversarial networks (GANs) subject to higher-order gradient regularization. We show analytically, via the least-squares (LSGAN) and Wasserstein (WGAN) GAN variants, that the discriminator optimization problem is one of high-dimensional interpolation. The optimal discriminator, derived using variational calculus, turns out to be the solution to a partial differential equation involving the iterated Laplacian or the polyharmonic operator. The solution is implementable in closed-form via polyharmonic radial basis function (RBF) interpolation. In view of the polyharmonic connection, we refer to the corresponding GANs as Poly-LSGAN and Poly-WGAN. As a proof of concept, the analysis is supported by experimental validation on multivariate Gaussians. While the closed-form RBF does not scale favorably with the dimensionality of data for image-space generation, we employ the Poly-WGAN discriminator to transform the latent space distribution of the data to match a Gaussian in a Wasserstein autoencoder (WAE). The closed-form discriminator, motivated by the polyharmonic RBF, results in up to 20% improvement in terms of Fréchet and kernel inception distances over comparable baselines that employ trainable or kernel-based discriminators. The experiments are carried out on standard image datasets such as MNIST, CIFAR-10, CelebA, and LSUNChurches. The training time in Poly-WGAN is comparable to those of kernel-based methods, while being about two orders faster than GANs with a trainable discriminator.
Lagrangian and Eulerian statistics obtained from direct numerical simulations of homogeneous turbulence

Lagrangian statistics have been obtained from direct numerical simulations of isotropic turbulence and homogeneous shear flow. Quantities presented include properties of the dispersion tensor 〈Xi(t)Xj(t)〉, isoprobability contours of particle displacement, Lagrangian and Eulerian velocity autocorrelations and time scale ratios, and the eddy diffusivity tensor. The dispersion measurements from the simulations of isotropic turbulence are in good agreement with those of Warhaft [J. Fluid Mech. 144, 363 (1984)] and Stapountzis et al. [J. Fluid Mech. 165, 401 (1986)]. ‘‘Integral’’ time scales were defined as the time required for the temporal correlations to decrease to 1/e of their initial value. The ratio of TeL/TeE from the simulations of isotropic turbulence was approximately 0.8, in good agreement with the data of Sato and Yamamoto [J. Fluid Mech. 175, 183 (1987)]. The principal angle of 〈Xi(t)Xj(t)〉 from the shear flow simulations shows reasonable agreement with a similar study done by Riley (Ph.D. disser.
Confocal scanning laser ophthalmoscope with adaptive optical wavefront correction

We have developed a new prototype of a confocal scanning laser ophthalmoscope that incorporate relatively low-cost adaptive optics to correct for wavefront aberrations induced in the exit path of the eye and the optical setup components. The scanning part of the system consists of two galvanometric scanners, and the adaptive optics part contains a membrane deformable mirror in conjunction with a Hartmann-Shack wavefront sensor. The system allows to register images of the retina with infrared illumination at a 15 Hz frame rate and with a variable viewing angle in the range of 1° to 10°. We show first results obtained with the system with images of a test target in an artificial eye and with imaging of the living human retina. We compare images obtained without and with the adaptive optics part activated. In preliminary images, retinal features down to a size of ~25 μm have been resolved with the application of adaptive optics.
Organization and Structure of Clouds and Precipitation on the Mid-Atlantic Coast of the United States. Part IV: Retrieval of the Thermodynamic and Cloud Microphysical Structures of a Frontal Rainband from Doppler Radar Data

Abstract The thermodynamic and cloud structure of a relatively weak wintertime frontal rainband are derived from dual-Doppler radar measurements, soundings and high resolution surface observations, and with a cloud model. These derivations are simplified by the high degree of two-dimensionality and steadiness of the rainband. Water vapor, cloud water, cloud ice, rain, and snow are parameterized in the cloud model, subject to a temperature distribution that is constrained to a dynamical balance. Air temperature is derived from buoyancy, which is retrieved from the airflow assuming momentum and heat balance. The results of the thermodynamic and cloud microphysical retrieval are compared with airborne measurements in the rainband. The analysis indicates that the rainband was driven by a weak cold front aloft (CFA), which made the prefrontal air conditionally symmetrically unstable. The CFA appeared as a midlevel intrusion of cold, dry air on the mesoγ scale. The CFA interacted dynamically with the planetary .
Nonparametric estimation of the bivariate survival function for one modified form of current-status data

In this article, the estimation of the bivariate survival function for one modified form of current-status data is considered. Two types of estimators, which are generalizations of the estimators by Campbell and Földes [G. Campbell and A. Földes, Large sample properties of nonparametric statistical inference, in Nonparametric Statistical Inference, B.V. Gnredenko, M.L. Puri, and I. Vineze, eds., North-Holland, Amsterdam, 1982, pp. 103–122] and Dabrowska [D.M. Dabrowska, Kaplan-Meier estimate on the plane, Ann. Stat. 18 (1988), pp. 1475–1489; D.M. Dabrowska, Kaplan-Meier estimate on the plane: weak convergence, LIL, and the bootstrap, J. Multivariate Anal. 29 (1989), pp. 308–325], are proposed. The consistency of the proposed estimators is established. A simulation study is conducted to investigate the performance of the proposed estimators.
Hough transform-based 3D mesh retrieval

This papre addresses the issue of 3D mesh indexation by using shape descriptors (SDs) under constraints of geometric and topological invariance. A new shape descriptor, the Optimized 3D Hough Transform Descriptor (O3HTD) is here proposed. Intrinsically topologically stable, the O3DHTD is not invariant to geometric transformations. Nevertheless, we show mathematically how the O3DHTD can be optimally associated (in terms of compactness of representation and computational complexity) with a spatial alignment procedure which leads to a geometric invariant behavior. Experimental results have been carried out upon the MPEG-7 3D model database consisting of about 1300 meshes in VRML 2.0 format. Objective retrieval results, based upon the definition of a categorized ground truth subset, are reported in terms of Bull Eye Percentage (BEP) score and compared to those obtained by applying the MPEg-7 3D SD. It is shown that the O3DHTD outperforms the MPEg-7 3D SD of up to 28%.
Environmental dependence of SFRs in late-type GAMA galaxies

Abstract Present and past gas-fuelling of galaxies is expected to depend upon both the properties of the galaxies themselves, as well as their larger-scale environments. In the case of galaxies in groups the environment, i.e the group mass, can be probed by measuring the velocity dispersion of the group members, as done with the GAMA Galaxy Group catalogue (Robotham et al. 2011), probing the halo mass function all the way to small groups. The gas-fuelling rate of normal late-type galaxies can be traced by the SFR under the assumption of a steady state between gas-fuelling and gas-consumption by SF. We present a method to estimate disk opacities from UV/optical photometric characteristics, calibrated using the radiative transfer model of Popescu et al. (2011), applied to UV-Opt-FIR GAMA/H-ATLAS photometry for a subset of GAMA galaxies. We use the method to extract attenuation corrected SFRs for a large sample of late-type GAMA galaxies, which we use in an initial application to constrain the dependency of star formation/gas-fuelling in late-type galaxies on mass of parent DMH, and compactness of galaxy group.
Interactions between number theory and image analysis

The conceptual design of many procedures used in image analysis starts with models which assume as an input sets in Euclidean space which we regard as real objects. However, the application finally requires that the Euclidean (real) objects have to be modelled by digital sets, i.e. they are approximated by their corresponding digitizations. Also 'continuous' operations (for example integrations or differentiations) are replaced by 'discrete' counterparts (for example summations or differences) by assuming that such a replacement has only a minor impact on the accuracy or efficiency of the implemented procedure. This paper discusses applications of results in number theory with respect to error estimations, accuracy evaluations, correctness proofs etc. for image analysis procedures. Knowledge about digitization errors or approximation errors may help to suggest ways how they can be kept under required limits. Until now have been only minor impacts of image analysis on developments in number theory, by defining new problems, or by specifying ways how existing results may be discussed in the context of image analysis. There might be a more fruitful exchange between both disciplines in the future.
Equation-free Model Reduction in Agent-based Computations: Coarse-grained Bifurcation and Variable-free Rare Event Analysis

We study the coarse-grained, reduced dynamics of an agent-based market model due to Omurtag and Sirovich []. We first describe the large agent number, deterministic limit of the system dynamics by performing numerical bifurcation calculations on a continuum approximation of their model. By exploring a broad parameter space, we observe several interesting phenomena including turning points leading to unstable stationary agent density distributions as well as a type of “termination point. ” Close to these deterministic turning points we expect the stochastic underlying model to exhibit rare event transitions. We then proceed to discuss a coarse-grained approach to the quantitative study of these rare events. The basic assumption is that the dynamics of the system can be decomposed into fast (noise) and slow (single reaction coordinate) dynamics, so that the system can be described by an effective, coarse-grained Fokker-Planck(FP) equation. An explicit form of this effective FP equation is not available; in our computations we bypass the lack of a closed form equation by numerically estimating its components - the drift and diffusion coefficients - from ensembles of short bursts of microscopic simulations with judiciously chosen initial conditions. The reaction coordinate is first constructed based on our understanding of the continuum model close to the turning points, and it gives results reasonably close to those from brute-force direct simulations. When no guidelines for the selection of a good reaction coordinate are available, data-mining tools, in particular Diffusion Maps, can be used to determine a suitable reaction coordinate. In the third part of this work we demonstrate this “variable-free” approach by constructing a reaction coordinate simply based on the data from the simulation itself. This Diffusion Map based, empirical coordinate gives results consistent with the direct simulation.
Conditioning analysis of parameter estimation in a synchronous generator

This paper presents the conditioning analysis of the parameter estimation problem for a synchronous generator. The analysis is performed in a small signal model of the generator. Results demonstrate the ill conditioning of the problem. Methodologies to handle the ill conditioning are presented. The proposed methodologies represent different ways to incorporate prior information about the synchronous generator parameter estimation problem to regularize the parameter estimates.
Alfvén Waves, Density Cavities and Electron Acceleration Observed from the FAST Spacecraft

Inertial Alfvén waves propagating in regions of auroral electron acceleration are observed from the FAST (Fast Auroral Snapshot) spacecraft over its entire altitude range (350–4180 km). These electron skin depth sized field structures are dispersive and carry an electric field component parallel to the geomagnetic field leading to a variety of non-linear effects including the formation of magnetic field-aligned density cavities and electron acceleration. High resolution measurements show that the electron distribution inside the impulsive wave field envelope or density cavity consists of a cold ionospheric component and an accelerated and heated field-aligned component comprised of downgoing and reflected ionospheric and magnetosheath (solar wind like) electrons. In large amplitude examples the plasma within the wave may be dominated by the accelerated component and the depletion of plasma within the cavity approaches 100%. Comparison of the observed density depletion with the predictions of ponderomotive density cavity formation in association with electron heating shows good agreement. Furthermore, simulations show that most of the observed features of the accelerated component can be explained through Landau resonance of the cold ionospheric and magnetosheath electrons with the inertial Alfvén wave as it propagates through an altitude dependent density profile.
Tight Focusing of Intense Pulsed Light-Ion Beam by Spherical “Plasma Focus Diode”

A new type of ion-beam diode, a self-magnetically insulated, spherical plasma focus diode was developed. With this diode, point focusing of an intense pulsed light-ion beam was obtained. Diagnostic results showed that the ion beam (0.8 MeV, 68 kA) was focused into a small cylinder with ∼0.5 mm diameter and ∼2.5 mm length. The estimated ion-beam current density and the power density were ∼680 kA/cm2 and ∼0.54 TW/cm2, respectively.
Method for optic nerve intensity characterization in mice from Mn2+ enhanced MR images

Investigating whether manganese transport is impaired in the optic nerve of small animal model is a new approach for evaluating optic neuritis. One needs to quantify signal intensity enhancement due to Mn2+ after intra-orbital injection, along the optic nerve from MR images. Quantification is very challenging as the optic nerve (ON) is not straight, its location does not correspond to standard slice orientation, the noise is substantial, and the signal is subject to inhomogeneity from the coil sensitivity. In this paper, we propose a semi-automatic method whereby 1) the retina point and the start of the chiasm in a mouse brain MR image are defined manually in a 3D visualization environment, 2) optic nerve in reformatted slices perpendicular to the optic nerve segment is semi-manually selected, 3) an automatic algorithm extracts the intensities along the optic nerve while correcting for intensity inhomogeneity, and 4) a model for the Mn2+ diffusion with a exponential decay function is fitted to the intensity profile. Results for the study of experimental autoimmune encephalomyelitis (EAE) are reported whereby statistically significant differences were found between the EAE and the control group.