Miracle-dz/UniFAR-FTUs huggingface dataset:
Control approach for tracking a moving target by a wheeled mobile robot with limited velocities

A mobile robot's motion is directly affected by the maximum velocity its actuators can provide. This problem becomes more serious when the robot tracks a moving target which imposes demanding requirements on the robot's driving capabilities. To find a solution to this problem, this paper extends the conventional Lyapunov-based motion controller while taking the limit on the robot's velocity into consideration. The effects of the target's motion are explicitly addressed in the controller design. The control outputs are attenuated by selected sinusoidal functions of the states without compromising the asymptotic stability of the controlled system. Next, a new Lyapunov function reflecting the priority of the tracking objectives is chosen to develop the controller which further reduces the surges and fluctuations of the controller outputs. The smoothness of the robot motion is improved, the reasonable magnitudes of the robot velocities and a better target tracking performance are achieved. Extensive simulation and experimental results in various situations are provided to verify the effectiveness of the proposed approaches.
CT-based attenuation correction for PET/CT scanners in the presence of contrast agent

In PET/CT tomographs the PET emission data can be corrected for photon attenuation effects using the CT images which are scaled from the mean CT energy of /spl sim/70 keV to the PET photon energy of 511 keV. The standard scaling approach requires segmenting the CT image voxels into soft tissue or bone using a single threshold of 300 H.U. and then applying two separate scale factors. In practice oral contrast may be administered leading to enhanced CT values that are not correctly handled by the standard scaling algorithm, which then leads to a bias in the PET emission image corrected for attenuation. A modified algorithm is proposed which transforms the oral contrast enhanced CT values to the correct 511 keV value, leading to unbiased attenuation correction factors.
Generalization error estimates and training data valuation

This thesis addresses several problems related to generalization in machine learning systems. We introduce a theoretical framework for studying learning and generalization. Within this framework, a closed form is derived for the expected generalization error that estimates the out-of-sample performance in terms of the in-sample performance. We consider the problem of overfitting and show that, using a simple exhaustive learning algorithm, overfitting does not occur. These results do not assume a particular form of the target function, input distribution or learning model, and hold even with noisy data sets. We apply our analysis to practical learning systems, illustrate how it may be used to estimate out-of-sample errors in practice, and demonstrate that the resulting estimates improve upon errors estimated with a validation set for real world problems. Based on this study of generalization, we develop a technique for quantitative valuation of training data. We demonstrate that this valuation may be used to select training sets that improve generalization performance. With a reasonable prior over target functions, it further allows us to estimate the level of noise in a data set and provides for detection and correction of noise in individual examples. Finally, this data valuation can be used to classify new examples, yielding a new learning algorithm that is shown to be relatively robust to noise.
Invariant nonlinear correlation and spectral index for diatoms recognition

We present a nonlinear correlation methodology to recognize objects. This system is invariant to position, rotation, and scale by using vectorial signatures obtained from the target such as those from problem images. Vectorial signatures are calculated through several mathematical transformations such as scale and Fourier transform. In this application, vectorial signatures are compared using nonlinear correlations. Also, experiments were carried out in order to find the noise tolerance. The discrimination coefficient was used as a metric in performance evaluation in presence of noise. In addition, spectral index and vectorial signature index are obtained in order to recognize objects in a simpler way. This technique has low computational cost. The invariance to position, rotation, and scale digital system was tested with 21 different fossil diatoms images. The results obtained are good, and the confidence level is above 95.4%. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). (DOI:
On nonparametric kernel density estimates

SUMMARY The paper introduces the idea of inadmissible kernels and shows that an Epanechnikov type kernel is the only admissible kernel. An analysis of kernel density estimates leads to two new methods of bias reduction. We also discuss a general method of improving kernel density estimates in the sense of having smaller mean squared error. Finally we provide a theoretical framework for the operational method of using Abramson's square root law providing tangible and compact forms for the bias and mean squared error.
The microphysical properties of tropical convective anvil cirrus: A comparison of models and observations

This paper describes the use of two‐dimensional (2‐D) cloud‐resolving numerical model simulations of a period of active convection from the Tropical Ocean‐Global Atmosphere Coupled Ocean‐Atmosphere Response Experiment to generate statistics of the distribution of total ice water content (IWC) and of the relative contribution to IWC of small (sub‐200 μm) particles with temperature. The model data are sampled in a way which excludes contributions from active convective updraught regions, so that the model results may be compared with similar such distributions derived from in situ sampling of a number of tropical anvil ice clouds in the vicinity of Kwajalein in the west Pacific.
Think outside the box: Incorporating secondary cognitive tasks into return to sport testing after ACL reconstruction

The optimal set of return to sport (RTS) tests after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) remains elusive. Many athletes fail to pass current RTS test batteries, fail to RTS, or sustain secondary ACL injuries if they do RTS. The purpose of this review is to summarize current literature regarding functional RTS testing after ACLR and to encourage clinicians to have patients “think” (add a secondary cognitive task) outside the “box” (in reference to the box used during the drop vertical jump task) when performing functional RTS tests. We review important criteria for functional tests in RTS testing, including task-specificity and measurability. Firstly, tests should replicate the sport-specific demands the athlete will encounter when they RTS. Many ACL injuries occur when the athlete is performing a dual cognitive-motor task (e.g., attending to an opponent while performing a cutting maneuver). However, most functional RTS tests do not incorporate a secondary cognitive load. Secondly, tests should be measurable, both through the athlete’s ability to complete the task safely (through biomechanical analyses) and efficiently (through measures of performance). We highlight and critically examine three examples of functional tests that are commonly used for RTS testing: the drop vertical jump, single-leg hop tests, and cutting tasks. We discuss how biomechanics and performance can be measured during these tasks, including the relationship these variables may have with injury. We then discuss how cognitive demands can be added to these tasks, and how these demands influence both biomechanics and performance. Lastly, we provide clinicians with practical recommendations on how to implement secondary cognitive tasks into functional testing and how to assess athletes’ biomechanics and performance.
Laser spectroscopy of the tin isotopes

Isotope shifts of all the stable isotopes and the hyperfine splittings of 115Sn, 117Sn and 119Sn have been measured in the transitions 5s25p23P0-5s25p6s3P1 at 286 nm in Sn I. Tin atoms in a collimated beam to reduce the Doppler width were excited by radiation at 286 nm generated by frequency doubling the light from a CW ring dye laser. Spectra were recorded by monitoring the subsequent decay and calibrated by optical heterodyning. The relative positions of the isotopes are, in MHz: 112; 0.0(1.0), 114;319.5(1.3), 115;412.7(1.1), 116;640.0(0.6), 117;746.8(0.7), 118;945.2(0.7), 119;1039.3(1.1), 120;1214.4(0.5), 122;1448.5(0.7), 124;1656.0(0.7). The bracketed uncertainties are added in quadrature to give the errors of the isotope shifts. For odd-even shifts involving 112, 114, 120, 122 and 124 an extra 0.5 MHz must be added in quadrature. The hyperfine splitting factors of 5s25p6s3P1 are, in MHz: A(115)=-4395.4 (2.1), A(117)=-4790.71(1.7), A(119)=-5014.8(1.9). The results are interpreted in terms of the electronic and nuclear properties of the tin isotopes.
Pruning and growing hierachical mixtures of experts

The 'hierarchical mixture of experts' (HME) is a tree-structured statistical model that is an alternative to multilayer perceptrons. Its training algorithm consists of a number of forward and backward passes through the tree. These are computationally expensive, especially when the trees are large. To reduce the computation, we may either allow the network to find its own structure in a constructive manner (tree growing) or consider only the most likely paths through the tree (path pruning). Pruning keeps the number of parameters constant but considers only the most likely paths through the tree at any time; this leads to significant speedups in training and evaluation. In the growing algorithm, we start with a small tree and apply a splitting criterion based on maximum likelihood to each terminal node. After splitting the best node according to this criterion, we retrain the tree for a set number of iterations, or until there is no further increase in likelihood, at which point the tree is grown again. This results in a flexible architecture which is both faster to train and more efficient in terms of its parameters. To aid the convergence of these algorithms, it is beneficial to introduce regularization into the HME, which stops the evolution of large weights which would otherwise cause branches of the tree to be pinched off. This also aids generalization, as we demonstrate on a toy regression problem. Results for the growing and pruning algorithms show significant speedups over conventional algorithms in discriminating between two interlocking spirals and classifying 8-bit parity patterns.
89 HERCULIS AND HD 161796 IN 1986 AND 1987

Data from UBV photometric observations of two UU Herculis stars, 89 Her and HD 161796, are presented for the period from 1986 to 1987. Light curves are presented for both stars in both years. The results show that the light curve of HD 161796 is much less stable than that of 89 Her. The periodicities and phasing of the light curves are discussed.
Nanoindentation of silicon nitride: A multimillion-atom molecular dynamics study

Nanoindentation of crystalline and amorphous silicon nitride films is studied using 10-million-atom molecular dynamics simulations. A rigid pyramid-shaped indenter tip is used. Load–displacement curves are computed and are used to derive hardness and elastic moduli of the simulated crystalline and amorphous films. Computer images of local pressure distributions and configuration snapshots show that plastic deformation in the film extends to regions far from the actual indent.
The maximum‐likelihood solution in inter‐battery factor analysis

Maximum-likelihood estimates in closed form are derived for Tucker's (1958) inter-battery factor analysis model. The estimates of inter-battery factor loadings may be computed by rescaling correlation coefficients between the original variables and the canonical variables obtained in canonical correlation analysis. It is shown that the likelihood ratio test for the number of inter-battery factors is identical to Bartlett's (1938) test for the number of non-zero canonical correlations. An alternative approach analogous to the maximum determinant approach of Howe (1955) and Bargmann (1957) is seen to yield the same solution as that obtained by maximum likelihood. The question of rotation of factors is discussed and an example is given.
HETEROGENEOUS LINK WEIGHT PROMOTES THE COOPERATION IN SPATIAL PRISONER'S DILEMMA

The spatial structure has often been identified as a prominent mechanism that substantially promotes the cooperation level in prisoner's dilemma game. In this paper we introduce a weighting mechanism into the spatial prisoner's dilemma game to explore the cooperative behaviors on the square lattice. Here, three types of weight distributions: exponential, power-law and uniform distributions are considered, and the weight is assigned to links between players. Through large-scale numerical simulations we find, compared with the traditional spatial game, that this mechanism can largely enhance the frequency of cooperators. For most ranges of b, we find that the power-law distribution enables the highest promotion of cooperation and the uniform one leads to the lowest enhancement, whereas the exponential one lies often between them. The great improvement of cooperation can be caused by the fact that the distributional link weight yields inhomogeneous interaction strength among individuals, which can facilitate the formation of cooperative clusters to resist the defector's invasion. In addition, the impact of amplitude of the undulation of weight distribution and noise strength on cooperation is also investigated for three kinds of weight distribution. Current researches can aid in the further understanding of evolutionary cooperation in biological and social science.
LIRAD Observations of Tropical Cirrus Clouds in MCTEX. Part I: Optical Properties and Detection of Small Particles in Cold Cirrus*

Abstract This paper presents further results on the optical properties of tropical and equatorial cirrus using the light detecting and ranging (lidar) radiometer (LIRAD) method. The results were obtained from observations in the Maritime Continent Thunderstorm Experiment (MCTEX). Values were obtained of cirrus cloud backscatter coefficient, infrared (IR) emittance, optical depth and absorption coefficient, cloud height and depth, and backscatter-to-extinction ratio. The values agree well with previous results obtained on equatorial cirrus in the Pilot Radiation Observation Experiment (PROBE) and extend those results to lower temperatures. Observations made of lidar linear depolarization ratio show similar trends to those observed in PROBE, extending those results to lower temperatures. Regressions of cloud IR emittance and absorption coefficients are performed as a preliminary tropical dataset for both cloud-resolving and climate models. These regressions are compared with previous regressions on midlatit.
Anti-control of Hopf bifurcations through washout filters

Bifurcation control generally means to design a controller that can modify the bifurcation characteristics of a bifurcating nonlinear system, thereby achieving some desirable dynamical behaviors. A typical objective is delay and/or stabilization of a given bifurcation. In this paper, we consider the problem of anti-control of bifurcations, that is, a certain bifurcation is created with desired location and properties by appropriate controls. In particular, washout filter-aided dynamic feedback control laws are given for the creation of Hopf bifurcations. As Hopf bifurcations give rise to limit cycles, anti-control of Hopf bifurcations can be viewed as one approach to design limit cycles and nonlinear oscillations into a system via feedback control when such dynamical behaviors are desirable.
A Comprehensive Review on Food Waste Reduction Based on IoT and Big Data Technologies

Food waste reduction, as a major application area of the Internet of Things (IoT) and big data technologies, has become one of the most pressing issues. In recent years, there has been an unprecedented increase in food waste, which has had a negative impact on economic growth in many countries. Food waste has also caused serious environmental problems. Agricultural production, post-harvest handling, and storage, as well as food processing, distribution, and consumption, can all lead to food wastage. This wastage is primarily caused by inefficiencies in the food supply chain and a lack of information at each stage of the food cycle. In order to minimize such effects, the Internet of Things, big data-based systems, and various management models are used to reduce food waste in food supply chains. This paper provides a comprehensive review of IoT and big data-based food waste management models, algorithms, and technologies with the aim of improving resource efficiency and highlights the key challenges and opportunities for future research.
Eigenvalue problems for the wave equation with strong damping

This paper presents a study of linear operators associated with the linearisation of general semilinear strongly damped wave equations around stationary solutions. The structure of the spectrum of such operators is considered in detail, with an emphasis on stability questions. Necessary and sufficient conditions for the stability of the trivial solution of the linear equation are given, together with conditions for this solution to become unstable. In the latter case, the mechanisms which are responsible for the change of stability are analysed. These results are then applied to obtain stability and instability conditions for the semilinear problem. In particular, a condition is given which ensures that the dimensions of the centre and unstable manifolds of a stationary solution are the same as when that solution is considered as a stationary solution of an associated parabolic problem.
X-ray emission properties of BLAGN in the XMM-2dF Wide Angle Survey

Abstract We present the preliminary results of the X-ray spectral analysis of one of the largest samples of X-ray selected BLAGN assembled so far from the XMM-2dF Wide Angle Survey. The sample, with 641 spectroscopically identified BLAGN, provides a unique resource to carry out a statistical analysis of the emission properties of these objects over a broad range of X-ray luminosities and redshifts. The X-ray spectra of the majority of the objects were best fitted with a power law with a near constant mean spectral photon index. No obvious trend of this spectral parameter with X-ray luminosity or redshift was found. We measured the mean photon index of our objects to be ∼1.96 ± 0.05 with an intrinsic dispersion σ=0.22±0.03. X-ray absorption was detected in ∼8% of the sources, with no preferred luminosity or redshift and having typical values of the absorbing column density ≤1022 cm−2.
The complex Bingham quartic distribution and shape analysis

Summary. The complex Bingham distribution was introduced by Kent as a tractable model for landmark‐based shape analysis. It forms an exponential family with a sufficient statistic which is quadratic in the data. However, the distribution has too much symmetry to be widely useful. In particular, under high concentration it behaves asymptotically as a normal distribution, but where the covariance matrix is constrained to have complex symmetry. To overcome this limitation and to provide a full range of asymptotic normal behaviour, we introduce a new ‘complex Bingham quartic distribution’ by adding a selection of quartic terms to the log‐density. In the simplest case this new distribution corresponds to Kent's FB5‐distribution. Asymptotic and saddlepoint methods are developed for the normalizing constant to facilitate maximum likelihood estimation. Examples are given to show the usefulness of this new distribution.
Catch-All No More: Integrative Systematic Revision of the Genus Allolobophora Eisen, 1874 (Crassiclitellata, Lumbricidae) with the Description of Two New Relict Earthworm Genera

The taxonomy of earthworms has been riddled by instability, lack of systematically useful characters, and lax diagnoses of some genera. This has led to the use of some genera such as Allolobophora Eisen, 1874 as taxonomic wastebaskets, blurring their evolution and biogeographical history. The implementation of molecular techniques has revolutionized the systematics of the genus; however, some of its species have not been previously included in molecular phylogenetic analyses. Thus, the molecular markers COI, 16S, ND1, 12S, and 28S were sequenced for six endemic species including several taxa of Allolobophora and Aporrectodea Örely, 1885 (another related catch-all genus). Phylogenetic relationships determined by Bayesian inference and maximum likelihood analyses support the status of two of the six taxa examined (Allolobophora burgondiae Bouché, 1972 and Aporrectodea icterica Savigny, 1826) as part of Allolobophora sensu stricto and a presumed synonymy between Allolobophora and Heraclescolex Qiu and Bouché, 1998. Branch lengths and average pairwise genetic distances support the transfer of Allolobophora satchelli Bouché, 1972 to the genus Panoniona Mršić and Šapkarev, 1988 and the emergence of two new genera, Heraultia gen. nov. and Vosgesia gen. nov., endemic to France, hosting Allolobophora tiginosa Bouché, 1972 and Allolobophora zicsii Bouché, 1972, respectively. The aforementioned changes of status and the diagnosis for Heraultia and Vosgesia are presented. These results provided more evolutionarily and biogeographically coherent earthworm groups and highlighted that the Maghreb and the area around the Alps are potential key locations for the diversification of Allolobophora and several lineages of Lumbricidae.
Numerical study of breaking waves by a two‐phase flow model

A two‐phase flow model, which solves the flow in the air and water simultaneously, is presented for modelling breaking waves in deep and shallow water, including wave pre‐breaking, overturning and post‐breaking processes. The model is based on the Reynolds‐averaged Navier–Stokes equations with the k −ε turbulence model. The governing equations are solved by the finite volume method in a Cartesian staggered grid and the partial cell treatment is implemented to deal with complex geometries. The SIMPLE algorithm is utilised for the pressure‐velocity coupling and the air‐water interface is modelled by the interface capturing method via a high resolution volume of fluid scheme. The numerical model is validated by simulating overturning waves on a sloping beach and over a reef, and deep‐water breaking waves in a periodic domain, in which good agreement between numerical results and available experimental measurements for the water surface profiles during wave overturning is obtained. The overturning jet, air entrainment and splash‐up during wave breaking have been captured by the two‐phase flow model, which demonstrates the capability of the model to simulate free surface flow and wave breaking problems.Copyright © 2011 John Wiley & Sons, Ltd.