Miracle-dz/UniFAR-FTUs huggingface dataset:
On analytical absorbing boundary conditions in FDTD

In this Letter a new algorithm to compute the corner‐point field components of a two‐dimensional (2‐D) Mur absorbing boundary condition (ABC) in the finite‐difference–time‐domain (FDTD) method is presented. It is shown that field value calculation at the corner points of the truncation domain affects the accuracy of the FDTD. The proposed scheme overcomes the drawbacks of reflection on the truncated boundary and computation divergence that may occur when the existing scheme is used. Numerical examples are illustrated to validate the effectiveness of the proposed scheme. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 437–440, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10344
Dynamical interactions between the coherent motion and small scales in a cylinder wake

Abstract Most turbulent flows are characterized by coherent motion (CM), whose dynamics reflect the initial and boundary conditions of the flow and are more predictable than that of the random motion (RM). The major question we address here is the dynamical interaction between the CM and the RM, at a given scale, in a flow where the CM exhibits a strong periodicity and can therefore be readily distinguished from the RM. The question is relevant at any Reynolds number, but is of capital importance at finite Reynolds numbers, for which a clear separation between the largest and the smallest scales may not exist. Both analytical and experimental tools are used to address this issue. First, phase-averaged structure functions are defined and further used to condition the RM kinetic energy at a scale $r$ on the phase $\phi $ of the CM. This tool allows the dependence of the RM to be followed as a function of the CM dynamics. Scale-by-scale energy budget equations are established on the basis of phase-averaged structure functions. They reveal that energy transfer at a scale $r$ is sensitive to an additional forcing mechanism due to the CM. Second, these concepts are tested using hot-wire measurements in a cylinder wake, in which the CM is characterized by a well-defined periodicity. Because the interaction between large and small scales is most likely enhanced at moderate/low Reynolds numbers, and is also likely to depend on the amplitude of the CM, we choose to test our findings against experimental data at $R_{\lambda } \sim 10^2$ and for downstream distances in the range $10 \leq x/D \leq 40$ . The effects of an increasing Reynolds number are also discussed. It is shown that: (i) a simple analytical expression describes the second-order structure functions of the purely CM. The energy of the CM is not associated with any single scale; instead, its energy is distributed over a range of scales. (ii) Close to the obstacle, the influence of the CM is perceptible even at the smallest scales, the energy of which is enhanced when the coherent strain is maximum. Further downstream from the cylinder, the CM clearly affects the largest scales, but the smallest scales are not likely to depend explicitly on the CM. (iii) The isotropic formulation of the RM energy budget compares favourably with experimental results.
Maximizing Future Potential in Physics and STEM: Evaluating a Summer Program through a Partnership between Science Outreach and Education Research.

Global competitiveness of the United States is often suggested as a key outcome of developing a capable science, technology, engineering, and mathematics (STEM) workforce, a goal supported by many local, state, and national programs. Examining the effectiveness of such programs, however, may require assessment techniques that are outside their organizers’ expertise. The physi cists conducting the physics outreach program in the current study partnered with education researchers at the same university to achieve a more thorough measure of program effective ness while also demonstrating how such partnerships represent an opportunity to add rigor to current evaluation. The resulting analyses demonstrated that participants in the outreach program (a) were more likely than nonparticipants to pursue an education and career in STEM, (b) were able to define and execute plans to solidify a strong foundation for pursuing a career in STEM, and (c) persisted in pursuing education in STEM after high school graduation.
Modelling non‐response in the National Child Development Study

Summary. There is widespread concern that the cumulative effects of the non‐response that is bound to affect any long‐running longitudinal study will lead to mistaken inferences about change. We focus on the National Child Development Study and show how non‐response has accumulated over time. We distinguish between attrition and wave non‐response and show how these two kinds of non‐response can be related to a set of explanatory variables. We model the discrete time hazard of non‐response and also fit a set of multinomial logistic regressions to the probabilities of different kinds of non‐response at a particular sweep. We find that the best predictors of non‐response at any sweep are generally variables that are measured at the previous sweep but, although non‐response is systematic, much of the variation in it remains unexplained by our models. We consider the implications of our results for both design and analysis.
Coordinated Standoff Tracking of Moving Targets Using Lyapunov Guidance Vector Fields

This paper presents a control structure for cooperative stand-off line-of-sight tracking of a moving target by a team of unmanned aircraft based on a Lyapunov guidance vector field that produces stable convergence to a circling limit cycle behavior. A guidance vector field is designed for a stationary target and then modified with a correction term that accounts for a moving target and constant background wind. Cooperative tracking by multiple unmanned aircraft is achieved through additional phasing, also with a Lyapunov stability analysis. Convoy protection, in which the unmanned aircraft must scout an area ahead of the moving target, is performed by extending the cooperative stand-offline-of-sight limit cycle attractor along the direction of travel. Simulation results demonstrate the behavior of the algorithms as well as the improvement that results from cooperation. Finally, simulations of a larger cooperative search, acquisition, and tracking scenario are described that illustrate the use of the cooperative standoff line-of-sight and convoy protection controllers in a realistic application.
Some recent problems in the field of microwave ferrites

Some recent developments and problems in the field of microwave ferrites will be reviewed. Properties which are considered interesting will be presented and discussed for materials with new chemical formulas in the spinel and garnet diagrams. Then we shall give an example of the physico-chemical problems brought up by the synthesis of ferrites with very low dielectric losses. Among the problems related to the micro-structure, materials with very small grains and those without porosity will be examined. The cation distribution between the crystallographic sites will be studied in another chapter. Then we shall try to discuss the experimental data available on microwave relaxation in polycrystalline ferrites. For that purpose, the effects of the relaxing ions and of the granular structure will be compared on \DeltaH, \DeltaH_{eff} and \DeltaH_{k} .
Complete separation of resonance and nonresonance channel spaces

The concept of ‘resonance channel space’ is proposed. Resonance states can decay into any open channels of common symmetry. They can also decay into any of the eigenchannels defined by diagonalizing the S matrix. However, an isolated resonance is known to decay only into a particular one of the eigenchannels (referred to as Q-eigenchannels) defined by diagonalizing the time-delay matrx , where the dagger indicates the Hermitian conjugate. This particular Q-eigenchannel corresponds to the eigenvalue of Lorentzian shape as a function of the energy E. A theorem generalizing this for N overlapping resonances is proved; only N eigenvalues of the Q matrix are nonzero and exhibit N Lorentzian profiles, avoiding each other around their crossing points, provided that the background S matrix is independent of E. Any of the overlapping resonances can decay only into the N Q-eigenchannels corresponding to these eigenvalues, and not to any other Q-eigenchannels. Thus, the set of Q-eigenchannels can be divided into ‘resonance channel space’, i.e. the subset of N Q-eigenchannels associated with the resonances and its complement completely irrelevant to the resonances asymptotically.
A Discussion of the Limitations of the Psychometric and Cultural Theory Approaches to Risk Perception

Risk perception has traditionally been conceived as a cognitive phenomenon, basically a question of information processing. The very term perception suggests that information processing is involved and of crucial importance. Kahneman and Tversky suggested that the use of 'heuristics' in the intuitive estimation of probabilities accounts for biased probability perception, hence claiming to explain risk perception as well. The psychometric approach of Slovic et al, a further step in the cognitive tradition, conceives of perceived risk as a function of general properties of a hazard. However, the psychometric approach is shown here to explain only about 20% of the variance of perceived risk, even less of risk acceptability. Its claim to explanatory power is based on a statistical illusion: mean values were investigated and accounted for, across hazards. A currently popular alternative to the psychometric tradition, Cultural Theory, is even less successful and explains only about 5% of the variance of perceived risk. The claims of this approach were also based on a statistical illusion: 'significant' results were reported and interpreted as being of substantial importance. The present paper presents a new approach: attitude to the risk generating technology, general sensitivity to risks and specific risk explained well over 60% of the variance of perceived risk of nuclear waste, in a study of extensive data from a representative sample of the Swedish population. The attitude component functioning as an explanatory factor of perceived risk, rather than as a consequence of perceived risk, suggests strongly that perceived risk is something other than cognition. Implications for risk communication are discussed.
An Extended Traffic Assignment Model with Applications to Two-Way Traffic

A transportation network is considered. The traffic demands associated with pairs of nodes and the traveling cost functions associated with the links are assumed given. An extended traffic assignment model where the traveling cost on a link becomes a function of the entire flow pattern in the network is introduced. The model appears particularly suitable for application to networks containing two-way streets, in view of its capability of taking into account delays to travelers of one lane caused by traffic on the opposite lane. It is also suitable for application to urban transportation networks, where the travel time on a link depends crucially on the delays occurring at the intersections. This in turn depends on the traffic volumes on the intersecting links. The concepts of system-optimizing and user-optimizing traffic patterns are studied. Moreover, an algorithm for the construction of the above patterns is presented and applied in an example.
Dynamic inference and everyday conditional reasoning in the new paradigm

One of the principal motivations for the new paradigm in reasoning was a reaction to the old (binary truth functional) paradigm's inability to deal with everyday non-monotonic inference. Within the new paradigm the problem of non-monotonicity is recast as the problem of belief revision or dynamic inference; that is, what happens when the probability distribution over which inferences are made changes from Pr0 to Pr1. Non-monotonicity arises when the new distribution, conditional on new information, I, changes the relevant probabilities, so that Pr0(x) ≠ Pr1(x), i.e., Pr0(x) ≠ Pr0(x|I). In this paper we first introduce the general problem of dynamic inference. We then consider the specific problems for dynamic conditional inference, in particular for modus tollens (MT). We then turn to possible reactions to these problems, looking at Oaksford and Chater's (2007) learning approach and causal Bayes nets. We conclude that most of the recent research on the non-monotonic effects observed in casual conditional inference and the suppression effect require a dynamic approach. However, the rational constraints on the transition from Pr0 to Pr1, when Pr0(x) ≠ Pr0(x|I), remain unclear.
Global Stability of a Couple-Stress Fluid in a Porous Medium Using a Thermal Non-Equilibrium Model

We show that the global nonlinear stability threshold for convection in a couple stress fluid with a thermal nonequilibrium model is exactly the same as the linear instability boundary. This optimal result is important because it shows that linearized instability theory has captured completely the physics of the onset of convection. It is also found that the couple stress fluid is more stable than the ordinary viscous fluid and then the effects of couple stress parameter, interface heat transfer coefficient, Darcy-Brinkman number and porosity modified conductivity ratio on the onset of convection have been investigated. Asymptotic analysis for both small and large values of interface heat transfer coefficient is also presented. An excellent agreement is found between the exact solutions and asymptotic solutions.
An equivalence induced by Ext and Tor applied to the finitistic weak dimension of coherent rings

Let R be a ring, see below for other notation. The functor categories (mod-R, Ab) and ((R-mod)op, Ab) have received considerable attention since the 1960s. The first of these has achieved prominence in the model theory of modules and most particularly in the investigation of the representation theory of Artinian algebras. Both [11, Chapter 12] and [8] contain accounts of the use (mod-R, Ab) may be put to in the model theoretic setting, and Auslander's review, [1], details the application of (mod-R, Ab) to the study of Artinian algebras. The category ((R-mod)op, Ab) has been less fully exploited. Much work, however, has been devoted to the study of the transpose functor between R-mod and mod-R. Warfield's paper, [13], describes this for semiperfect rings, and this duality is an essential component in the construction of almost split sequences over Artinian algebras, see [4]. In comparison, the general case has been neglected. This paper seeks to remedy this situation, giving a concrete description of the resulting equivalence between (mod-R, Ab) and ((R-mod)op, Ab) for an arbitrary ring R.
Calculation of the resistance and mobility functions for two unequal rigid spheres in low-Reynolds-number flow

Two unequal rigid spheres are immersed in unbounded fluid and are acted on by externally applied forces and couples. The Reynolds number of the flow around them is assumed to be small, with the consequence that the hydrodynamic interactions between the spheres can be described by a set of linear relations between, on the one hand, the forces and couples exerted by the spheres on the fluid and, on the other, the translational and rotational velocities of the spheres. These relations may be represented completely by either a set of 10 resistance functions or a set of 10 mobility functions. When non-dimensionalized, each function depends on two variables, the non-dimensionalized centre-to-centre separation s and the ratio of the spheres’ radii λ. Two expressions are given for each function, one a power series in s−1 and the other an asymptotic expression valid when the spheres are close to touching.
Statistical tools to select for robustness and milk quality

This work was part of the EU RobustMilk project. In this work package, we have focused on two aspects of robustness, micro- and macro-environmental sensitivity and applied these to somatic cell count (SCC), one aspect of milk quality. We showed that it is possible to combine both categorical and continuous descriptions of the environment in one analysis of genotype by environment interaction. We also developed a method to estimate genetic variation in residual variance and applied it to both simulated and a large field data set of dairy cattle. We showed that it is possible to estimate genetic variation in both micro- and macro-environmental sensitivity in the same data, but that there is a need for good data structure. In a dairy cattle example, this would mean at least 100 bulls with at least 100 daughters each. We also developed methods for improved genetic evaluation of SCC. We estimated genetic variance for some alternative SCC traits, both in an experimental herd data and in field data. Most of them were highly correlated with subclinical mastitis (>0.9) and clinical mastitis (0.7 to 0.8), and were also highly correlated with each other. We studied whether the fact that animals in different herds are differentially exposed to mastitis pathogens could be a reason for the low heritabilities for mastitis, but did not find strong evidence for that. We also created a new model to estimate breeding values not only for the probability of getting mastitis but also for recovering from it. In a progeny-testing situation, this approach resulted in accuracies of 0.75 and 0.4 for these two traits, respectively, which means that it is possible to also select for cows that recover more quickly if they get mastitis.
Automatic calculation of electron density profiles from digital ionograms: 3. Processing of bottomside ionograms

Automatic scaling of bottomside Digisonde ionograms gives the E and F region echo traces with high accuracy. Polarization and incidence angle information in the ionogram enables the extraction of the vertical, ordinary polarization echo trace from quiet as well as disturbed ionograms. The scaling algorithm is tested with Digisonde ionograms from Goose Bay, Labrador, which show spread F about 50% of the time. Despite these disturbed conditions, f0 F2 is determined within ½ MHz for 475 ionograrns out of 577 during January 1980. A profile inversion algorithm calculates the electron density profile from the autoscaled h′(ƒ) points. Parabolic profile shapes are assumed for the E region and the valley between the E and the F layer. The F layer is approximated by a single sum of Chebyshev polynomials, and the entire profile is described by a set of 16 numerical values. The CPU time required for ionogram scaling and electron density profile calculation is 14 s on a Cyber 71 computer. In addition to the profile the program outputs all relevant ionogram parameters: critical frequencies, minimum virtual heights, frequency and range spread, average echo amplitudes, and Doppler shifts.
Sodium enrichment of the stellar atmospheres. II. Galactic Cepheids

The present paper is a continuation of our study of the sodium abundance in supergiant atmospheres (Andrievsky et al. 2002a). We present the results on the NLTE abundance determination in Cepheids, and the derived relation between the sodium overabundance and their masses. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Time-dependent evaporation of icy mantles in hot cores

Hot cores are rich in saturated molecules that are believed to arise from the evaporation of molecular ices on dust grains. It is usually assumed that the ices are evaporated instantaneously when a nearby star is switched on. We have developed a new model in which the grain temperature rises over a time-scale determined by the switch-on time of the star. This time-scale is likely to be comparable to the lifetime of the hot cores. In consequence, evaporation of different species occurs at different epochs, leading to chemical differentiation in time and space within the hot core. By computing qualitative models of hot cores, we show that observations of hot cores may be able to constrain the rise time of hot stars to the main sequence.
On the strong consistency, weak limits and practical performance of the ML estimate and Bayesian estimates of a symmetric domain in $R^k$

: This paper considers a problem of estimating an unknown sym- metric region in R k based on n points randomly drawn from it. The domain of interest is characterized by two parameters: size parameter r and shape parameter p . Three methods are investigated which are the maximum likelihood, Bayesian procedures, and a composition of these two. A modiﬁcation of Wald’s theorem as well as a Bayesian version of it are given in this paper to demonstrate the strong consistency of these estimates. We use the measures of symmetric diﬀerences and the Hausdorﬀ distance to assess the performance of the estimates. The results reveal that the composite method does the best. Discussion on the convergence in distribution is also given.
Research on the Prediction of Protein Functional Sites Based on the Dimension Reduction Algorithm

Knowing the ProteinRNA interactions often provides useful clues for finding its biological function in a biological system. Dimension reduction method is one of most famous machine learning tools. Some researchers have begun to explore dimension reduction method for computer vision problems. Few such attempts have been made for classification of high-dimensional protein data sets. Here, dimensionality reduction algorithm is introduced to predict the protein-RNA interaction sites. Our jackknife test results indicate that it is very promising to use the dimensionality reduction approaches to cope with complicated problems in biological systems, such as predicting the protein-RNA interaction sites.
A note on Kolmogorov's −5/3 scaling law in a non-inertial frame of reference

This note presents a theoretical study on Kolmogorov's −5/3 scaling law under a change of frame of reference and, in particular, its corresponding form in a non-inertial frame of reference. First, we show that the Kolmogorov scales in the universal equilibrium range and the turbulent kinetic energy spectrum function E(κ, t) are not frame-indifferent, i.e., frame-dependent, in the sense of Truesdell and Noll (1965). Moreover, we investigate the aspects of the scaling coefficient C K under a change of frame of reference and arrive at a generalized Kolmogorov's −5/3 scaling law in a non-inertial frame of reference, which is frame-dependent and in an inertial frame of reference reduces to the form stemming from Kolmogorov's 1941 paper.
Eigenfunctions in chaotic quantum systems

The structure of wavefunctions of quantum systems strongly depends on the underlying classical dynamics. In this text a selection of articles on eigenfunctions in systems with fully chaotic dynamics and systems with a mixed phase space is summarized. Of particular interest are statistical properties like amplitude distribution and spatial autocorrelation function and the implication of eigenfunction structures on transport properties. For systems with a mixed phase space the separation into regular and chaotic states does not always hold away from the semiclassical limit, such that chaotic states may completely penetrate into the region of the regular island. The consequences of this flooding are discussed and universal aspects highlighted.