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Empirical studies have emphasized that the equity implied volatility is characterized by a negative skew inversely proportional to the square root of the time-to-maturity. We examine the short-time-to-maturity behavior of the implied volatility smile for pure jump exponential additive processes. An excellent calibration of the equity volatility surfaces has been achieved by a class of these additive processes with power-law scaling. The two power-law scaling parameters are β , related to the variance of jumps, and δ , related to the smile asymmetry. It has been observed, in option market data, that β = 1 and δ = - 1 / 2 . In this paper, we prove that the implied volatility of these additive processes is consistent, in the short-time, with the equity market empirical characteristics if and only if β = 1 and δ = - 1 / 2 . [ABSTRACT FROM AUTHOR]

We evaluated within-person variability across a cognitive test battery by analyzing the shape of the distribution of each individual's scores within a battery of tests. We hypothesized that most healthy adults would produce test scores that are normally distributed around their own personal battery-wide, within-person (wp) mean. Using cross-sectional data from 327 neurologically healthy adults, we computed each person's mean, standard deviation, skew, and kurtosis for 30 neuropsychological measures. Raw scores were converted to T -scores using three degrees of calibration: (a) none, (b) age, and (c) age, sex, race, education, and estimated premorbid IQ. Regardless of calibration, no participant showed abnormal within-person skew (wpskew) and only 10 (3.1%) to 16 (4.9%) showed wpkurtosis greater than 2. If replicated in other samples and measures, these findings could illuminate how healthy individuals are endowed with different cognitive abilities and provide the foundation for a new method of inference in clinical neuropsychology. [ABSTRACT FROM AUTHOR]

Purpose: Artifacts from poor ureteroscopes’ light design with shadowing and dark areas in the field of view have been reported. The aim was to quantify effects of light obstruction in a kidney calyx model. Methods: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU Wiscope using an enclosed 3D-printed pink in vitro kidney calyx model submerged in saline, where the field of light was intentionally partially obstructed alternatively at 12, 3, 6, and 9 o’clock. A color spectrometer was used for illuminance measurements at a 45° opening position in the background of the model. Results: Overall and mean background illuminance for each obstructive situation were significantly different between scopes for both 50% and 100% brightness settings (ANOVA p < 0.001). At 50% brightness setting, almost all scopes had their highest and lowest background illuminance with the 6 o’clock and 3 o’clock obstructive situation, respectively. At 100% brightness setting, these became 6 o’clock and 12 o’clock obstructive situations. Considering each obstructive situation individually, the Flex-Xc was consistently the scope with highest background illuminance and the Pusen 7.5F the lowest. Background illuminance for each obstructive situation varied significantly for each scope individually, with the greatest range of variability for Pusen 7.5F and V3. Conclusions: Illuminance performance of ureteroscopes within an obstructed calyx model differ significantly for various obstructive situations. Urologists should be aware of this to help guide their choice of ureteroscope. [ABSTRACT FROM AUTHOR]

Abstract In this article, the application of an artificial neural network (ANN)-based machine learning (ML) strategy to predict the coupled frequency of geometrically skewed multiphase magnetoelectric (MME) composite plate exposed to hygrothermal environment is presented. The ANN model is trained using a dataset comprising more than one million simulations conducted using an in-house developed finite element formulation. The underlying multiphysics governing equations are derived using Hamilton’s principle and higher-order shear deformation theory (HSDT). The influence of the hygrothermal environment on the elastic stiffness of MME composites is defined by the empirical constants in the constitutive relations. Four prominent combinations of the empirical constants leading to different elastic stiffness relations have been considered in this study. Alongside, the influence of geometrical skewness on the coupled fundamental frequency is also assessed. For the training of the ANN model, the Levenberg–Marquardt optimization algorithm with 30 neurons along with a tangent sigmoid activation function is used. The trained ANN model is tested on an unseen dataset, different from the training data, and it is shown to accurately predict the natural frequency of MME plate with a maximum error of 2.3%. Further, excluding the training time and considering the computational time alone, the ANN model is found to be 6.3 times faster than the FE simulations. It is anticipated that such ML-based reduced order models can be effective in the design process, especially in complex multiphysics problems, such as the one considered in the work, involving a multitude of geometric, loading and material parameters. [ABSTRACT FROM AUTHOR]

Phenological distributions are characterized by their central tendency, breadth, and shape, and all three determine the extent to which interacting species overlap in time. Pollination mutualisms rely on temporal co‐occurrence of pollinators and their floral resources, and although much work has been done to characterize the shapes of flower phenological distributions, similar studies that include pollinators are lacking. Here, we provide the first broad assessment of skewness, a component of distribution shape, for a bee community. We compare skewness in bees to that in flowers, relate bee and flower skewness to other properties of their phenology, and quantify the potential consequences of differences in skewness between bees and flowers. Both bee and flower phenologies tend to be right‐skewed, with a more exaggerated asymmetry in bees. Early‐season species tend to be the most skewed, and this relationship is also stronger in bees than in flowers. Based on a simulation experiment, differences in bee and flower skewness could account for up to 14% of pairwise overlap differences. Given the potential for interaction loss, we argue that difference in skewness of interacting species is an underappreciated property of phenological change. [ABSTRACT FROM AUTHOR]

Low speed and high torque permanent magnet synchronous motors are used in elevator applications. In these motors, the cogging torque causes negative effects. The cogging torque is a magneto-static effect caused by the change in magnetic attractiveness and repulsiveness surrounding the rotor magnets during the rotation of the rotor itself. This torque causes ripple and noise hence, it must be reduced especially at small loads and low speeds. For this reason, the focus of this study is to design a Permanent Magnet Synchronous Motor (PMSM) with high efficiency, power density and torque/ volume rate, and with reduced undesired cogging torque. Designed motor in aforementioned criteria has been analyzed with different skew lengths to reduce the cogging torque. The effects of the skew on the motor torque, cogging torque, efficiency, and harmonics are investigated. The graphics and the tables are obtained sequentially for each skew length. The skew rate is selected as 0.5 on the table to get a required performance in prototype manufacturing. Therefore, it makes the motor performance higher and reduce the torque ripple, vibration, and acoustic noise. The designed PMSM will be used to carry the elevator cabin between the floors. Due to centrifugal force, the PM motors are usually designed as inset magnet in rotor side. On the contrary in this study, the PMs are mounted on the surface of the rotor because of the low speed. All of the designs are confirmed by using the CD-Adapco Speed software based on Finite Element Method (FEM). [ABSTRACT FROM AUTHOR]

This article proposes a new high-fidelity simulation model of an induction motor (IM) based on finite-element analysis (FEA). The proposed model enables fast and accurate IM simulation with the inverter circuit model and control algorithm. That is, the proposed model can represent non-ideal features of IM, such as magnetic saturation, spatial harmonics, skew, and saturation-induced saliency in high accuracy. To construct the proposed model, a dq equivalent circuit of the squirrel cage rotor is introduced. Based on this, the static FEA is conducted which can accelerate the model construction compared to the conventional time-stepping FEA technique. Then, a flux-based IM model is established, which has advantages on speed, accuracy, and memory size in the simulation. To verify the effectiveness of the proposed model, the models are constructed for two commercial IMs used for the industrial drive. IM control algorithms are tested in various operating conditions on the proposed model. The results are compared with the time-stepping FEA and the experiment for the verification of the proposed model. [ABSTRACT FROM AUTHOR]

The motor in high-power electric vehicle (EV) easily reached the voltage limit because of its large magnetic flux. Therefore, the motor should be designed so that the voltage is controlled at the limit. To achieve well voltage control condition, the interior permanent-magnet synchronous motor (IPMSM) is controlled by the field-weakening control method after the constant torque region. This is conducted by canceling the magnetic flux from the permanent magnet with the magnetic flux of the stator winding. However, this method generates many harmonics. In this article, a design that effectively controls the voltage by reducing the harmonics generated in the field-weakening control is proposed. To reduce the harmonics in the field-weakening region, the change stator and rotor design parameters and the reason for using V-type permanent magnet arrangement for high-speed operation will be elucidated. [ABSTRACT FROM AUTHOR]

An integrated motor-compressor synergistically combines a flux-switching permanent magnet machine with an axial-flow compressor by shaping the rotor poles of the motor into airfoils. The airfoil-shaped rotor functions as the rotor of a motor as well as the rotor of an axial-flow compressor. The airfoil-shaped rotor poles need to be skewed by the proper blade stagger angle to obtain optimal fluid mechanics performance. The objective of this article is to investigate the effects of the stagger angle (skew) of the airfoil-shaped rotor on the thermodynamic and fluid mechanics performance of the integrated motor-compressor by mean line calculations and computational fluid dynamics (CFD). The skewing effects on the electromagnetic performance of the integrated motor-compressor with aligned and unaligned stator-rotor configurations are also investigated by analytical equations and three-dimensional finite-element analysis. A prototype is built for the integrated motor-compressor. Experimental results are also included to validate the simulations. [ABSTRACT FROM AUTHOR]

Characteristic cracks in skewed bridges, detrimental to service performance, form in deck acute corners and run diagonally across deck span. This paper presents the relationship between skew and deck cracks, investigates crack mitigation strategies and documents changes in live load distribution caused by cracks. Finite element analyses of in-service steel and concrete girder bridges were performed and qualitatively validated. The analyses were used to study the influence of skew angle, deck reinforcement amount and orientation, end diaphragm and girder restraint on deck strains and on live load distribution for shear (i.e., live load distribution to girders as vertical shear forces) from cracked decks to girders. The results showed that high skew induces stresses high enough to cause typical diagonal deck cracking on skewed bridges due to deck shrinkage. Restraint provided by end diaphragms, particularly by full depth concrete diaphragms and diaphragms connected to deck, magnify deck stresses. Orienting transverse deck reinforcement perpendicular to bridge centreline is more effective than parallel to substructure. Larger deck reinforcement cross-sectional areas increased deck restraint and likelihood of cracking. Shear live load reaction in exterior girders of the bridges studied increased by 35% due to deck cracks, although it remained smaller than interior girder reaction. [ABSTRACT FROM AUTHOR]

Axial flux permanent magnet synchronous motors (AFPMSMs) have advantages over other motor types in terms of efficiency, vibration, and noise. However, torque ripple is an important problem for axial flux permanent magnet (AFPM) motors. One of the methods recommended as a solution to this problem is the skew operation. The skew can be applied to the magnets or the stator. However, for these motors, this process is mostly applied to magnets because the skew applied to the stator makes it difficult to manufacture. In this article, a solution to the torque ripple of an in-wheel AFPMSM for the electric vehicle is sought. For this purpose, designs, optimization, and 3-D analyzes have been carried out. This solution has been applied to magnets designed by skewing for ease of production. 3-D analyses have been carried out by applying skew of up to 40° with an angle of 5° to the magnets in the rotor. In light of the analysis, the most appropriate skew angle that does not affect motor performance has been determined. As a result of the analysis of the motor model obtained with the determined skew angle, it is observed that the torque ripple decreased by 86.71%. Finally, production has been carried out according to the analysis results obtained. [ABSTRACT FROM AUTHOR]

Skew is taken into account in single- and multi-slice 2-D finite-element machine models by skew interface conditions applied at a cylinder hull in the center of the air gap. A set of biorthogonal basis functions is constructed to discretize the tangential magnetic field strength at the interface and to weakly enforce the tangential continuity of the magnetic vector potential. The harmonic filtering as a result of skew is already observed in a single-slice model. Multi-slice models with different numbers of stator and rotor slices increase the modeling accuracy. [ABSTRACT FROM AUTHOR]

The time resolution of active pixel sensors whose timestamp mechanism is based on time-to-digital converters is critically linked to the accuracy in the distribution of the master clock signal that latches the timestamp values across the detector. The clock distribution network (CDN) that delivers the master clock signal must compensate process–voltage–temperature variations to reduce static time errors (skew) and minimize the power supply bounce to prevent dynamic time errors (jitter). To achieve sub-100-ps time resolution within pixel detectors and thus enable a step forward in multiple imaging applications, the network latencies must be adjusted in steps well below that value. Power consumption must be kept as low as possible. In this work, a self-regulated CDN that fulfills these requirements is presented for the FastICpix single-photon detector aiming at a 65-nm process. A 40-MHz master clock is distributed to 64 × 64 pixels over an area of 2.4 × 2.4 cm2 using digital delay-locked loops, achieving clock leaf skew below 20 ps with a power consumption of 26 mW. Guidelines are provided to adapt the system to arbitrary chip area and pixel pitch values, yielding a versatile design with very fine time resolution. [ABSTRACT FROM AUTHOR]

Timing skew between measurement channels can introduce an unacceptable error in power loss measurement and is difficult to quantify, rendering precise in-situ measurement of magnetic loss essentially unattainable. This article rams the issue head-on by presenting the mathematical model for the timing skew and developing two methods based on the model to realize in-situ direct magnetic loss measurement. The mathematical model is first established to analyze the effects of timing skew on the measured magnetic loss in a dc–dc converter. The first method, called intersection method, illustrates how to unravel the entangled relationship between the actual timing skew and real magnetic loss in the circuit with the aid of the mathematical model. The second method, called derivative method, builds on the intersection method and greatly enhances the accuracy and the repeatability of the loss measurement. Our novel approach for in-situ magnetic loss measurement is verified in simulation and experiment with a conventional dc–dc step-down buck converter under various operating conditions and design parameters. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to attempt the buckling analysis of a laminated composite skew plate using the C0 finite element (FE) model based on higher-order shear deformation theory (HSDT) in conjunction with minimax probability machine regression (MPMR) and multivariate adaptive regression spline (MARS). Design/methodology/approach: HSDT considers the third-order variation of in-plane displacements which eliminates the use of shear correction factor owing to realistic parabolic transverse shear stresses across the thickness coordinate. At the top and bottom of the plate, zero transverse shear stress condition is imposed. C0 FE model based on HSDT is developed and coded in formula translation (FORTRAN). FE model is validated and found efficient to create new results. MPMR and MARS models are coded in MATLAB. Using skew angle (α), stacking sequence (Ai) and buckling strength (Y) as input parameters, a regression problem is formulated using MPMR and MARS to predict the buckling strength of laminated composite skew plates. Findings: The results of the MPMR and MARS models are in good agreement with the FE model result. MPMR is a better tool than MARS to analyze the buckling problem. Research limitations/implications: The present work considers the linear behavior of the laminated composite skew plate. Originality/value: To the authors' best of knowledge, there is no work in the literature on the buckling analysis of a laminated composite skew plate using C0 FE formulation based on third-order shear deformation theory in conjunction with MPMR and MARS. These machine-learning techniques increase efficiency, reduce the computational time and reduce the cost of analysis. Further, an equation is generated with the MARS model via which the buckling strength of the laminated composite skew plate can be predicted with ease and simplicity. [ABSTRACT FROM AUTHOR]

Plates are being widely used for many structural applications such as aerospace, civil, electronic devices and marine industries etc. For these applications, it is important to know the plate behaviour under static loading condition. The present study focuses on filling the existing gap in the literature in order to know the plate behaviour of different geometrical shapes before and after adding the stiffener. A total of eight geometries namely circular, square, rectangular (with aspect ratio of 1.25, 1.50 and 1.75) and skew square (with 70o, 76.67o and 83.33o skew angles) were considered. Static analysis of considered geometries was carried out by using FEAST (a Finite Element software). To enable comparison of plates, three parameters namely the area of plates, starting point of the stiffener and curvature of the stiffener were kept constant. From the static analysis results, the effect of the curvilinear stiffener on different geometrical shapes, effect of aspect ratio on rectangular plates and effect of skew angle on skew square plates were given. The displacement of plates reduced significantly after adding the curvilinear stiffener to the bare plates and the stiffener was most effective in the case of circular plate. In the present study, the effect of aspect ratio and skew angle on static behaviour of bare and stiffened plates was also studied and discussed. [ABSTRACT FROM AUTHOR]

Adaptation in spatially heterogeneous environments results from the balance between local selection, mutation, and migration. We study the interplay among these different evolutionary forces and demography in a classical two-habitat scenario with asexual reproduction. We develop a new theoretical approach that goes beyond the Adaptive Dynamics framework, and allows us to explore the effect of high mutation rates on the stationary phenotypic distribution. We show that this approach improves the classical Gaussian approximation, and captures accurately the shape of this equilibrium phenotypic distribution in one- and two-population scenarios. We examine the evolutionary equilibrium under general conditions where demography and selection may be nonsymmetric between the two habitats. In particular, we show how migration may increase differentiation in a source-sink scenario. We discuss the implications of these analytic results for the adaptation of organisms with large mutation rates, such as RNA viruses. [ABSTRACT FROM AUTHOR]

This paper analyzes skew due to unavoidable mechanical tolerances of a universal serial bus (USB) 2.0 cable. The contribution of the tolerances to the skew is determined via full-wave simulation of the cable cross section. The contributing factors and interaction terms are found using fractional factorial experimental design. Each factor's sensitivity to skew is investigated using Monte Carlo simulations. The design of experiments approach allows recognition of the relationship between the mechanical tolerances and skew. The skew-emission relationship, however, is found through a systematic approach. It was observed that adding about 20–30 ps net skew leads to about 4–5 dB increase in the emission above 350 MHz. [ABSTRACT FROM AUTHOR]

Sample-time error (STE) between time-interleaved channels is one of the main limitations on the performance of time-interleaved digital to analog converters (DACs). This paper presents techniques for detecting and correcting the STE in ultra-high speed 53 GBaud 4-level pulse amplitude modulation (PAM4) with a 2-bit DAC. Simulation results and lab measurements of a TSMC 16 nm CMOS process are presented. Test results show that the peak-to-peak STE of the 53 GBaud DAC is improved by more than one order of magnitude. [ABSTRACT FROM AUTHOR]

In order to study the relationship between ship propeller cavitation and induced pressure fluctuations, two propellers with different skew patterns are designed. The RANS method and the Schneer & Sauer cavitation model were used to solve the cavitation flow of the HSP-Ⅱpropeller and the results were in agreement with the measured data. At the cavitation condition, the balanced skew propeller shows a smaller cavitation volume than the biased skew propeller; for monitoring points above the propeller, skew type has little effect on the pressure fluctuations, the balanced propeller shows slightly lower pressure fluctuations. For a clockwise propeller (from the stern), the pressure fluctuations on the starboard are stronger than the port side. Finally, the fast Fourier transform (FFT) of the pressure signal shows that whether it is cavitation or full wetted flow, the point above the propeller contains first 3 harmonics of blade passing frequency (BPF), while the point in the wake shows only 1BPF at cavitation condition. [ABSTRACT FROM AUTHOR]

Curvature of recorded bit and skew are two factors limiting further improvement of the areal density capacity of heat-assisted magnetic recording. Performance degradation due to curvature and skew is evaluated using micromagnetic modeling and spin-stand measurements. Here, we propose two techniques for curvature reduction. One is a forked writer which can provide a cross-track magnetic field gradient that, combined with the thermal profile, mitigates the curvature of the recorded transitions. The other is a near-field transducer (NFT) design which can provide flat temperature contour at the write positions. The forked writer has practical limitations, such as short rise time requirement and insufficient field gradient, when it is integrated with NFTs. By comparing two types of NFT designs which providing curved and straight transitions, respectively, curvature is shown to be the main noise sources at certain track densities. Curvature reduction can provide more bit error rate gain for the same signal-to-noise ratio improvement. On the other hand, we also show that NFTs producing transitions with less curvature usually have the lower thermal gradient. Therefore, curvature and thermal gradient are two design targets that need to be balanced to provide the best recording performance. We also investigate the effect of recording skew on curvature at fixed linear velocity. At skew, the reader sees more curvature, which is one of the primary noise sources at non-zero skew. Consequently, the cross-track reader position should be optimized as a function of skew angle to reduce the effect of curvature. [ABSTRACT FROM AUTHOR]

This paper is a study on the application position of skew in order to reduce the cogging torque of a magnetic geared synchronous motor (MGM). The cogging torque affects the noise and vibration of the motor, so it should be reduced as much as possible. To solve this problem, a conventional permanent magnet (PM) synchronous motor is skewed to a PM. However, unlike other synchronous motors, the MGM has pole pieces (PPs), and a larger cogging torque is generated due to a larger reluctance difference. There have been few studies on the reduction of cogging torque of MGM, so it is essential to study the skew structure of MGM. Therefore, this paper has derived the optimum skew method by comparing and analyzing three models of MGM skewed to PM, PP, and PM and PP simultaneously. [ABSTRACT FROM AUTHOR]

Most study samples show less variability in key variables than do their source populations due most often to indirect selection into study participation associated with a wide range of personal and circumstantial characteristics. Formulas exist to correct the distortions of population-level correlations created. Formula accuracy has been tested using simulated normally distributed data, but empirical data are rarely available for testing. We did so in a rare data set in which it was possible: the 6-Day Sample, a representative subsample of 1,208 from the Scottish Mental Survey 1947 of cognitive ability in 1936-born Scottish schoolchildren (70,805). 6-Day Sample participants completed a follow-up assessment in childhood and were re-recruited for study at age 77 years. We compared full 6-Day Sample correlations of early-life variables with those of the range-restricted correlations in the later-participating subsample, before and after adjustment for direct and indirect range restriction. Results differed, especially for two highly correlated cognitive tests; neither reproduced full-sample correlations well due to small deviations from normal distribution in skew and kurtosis. Maximum likelihood estimates did little better. To assess these results’ typicality, we simulated sample selection and made similar comparisons using the 42 cognitive ability tests administered to the Minnesota Study of Twins Reared Apart, with very similar results. We discuss problems in developing further adjustments to offset range-restriction distortions and possible approaches to solutions. [ABSTRACT FROM AUTHOR]

The relationship between edge placement error (EPE), semiconductor design-rule determination, and predicted yield in the era of EUV lithography is examined, starting with the basics of EPE and then building up to design-rule calculations. The EPE definitions can be used as the building blocks for design-rule equations. Next the concept of "good fields" is explored and used to predict the n-sigma value needed for design-rule determination. Specifically, fundamental yield calculations based on the failure opportunities per chip are used to determine at what n-sigma value design-rules need to be tested to ensure high yield. The "value" can be a space between two features, an intersect area between two features, a minimum area of a feature, etc. It is shown that across-chip variation of design-rule important values needs to be tested at sigma values between seven and eight, which is much higher than the 4-sigma values traditionally used for design-rule determination. After recommending new statistics be used for design-rule calculations, we examine the impact of EUV lithography on sources of variation important for design-rule calculations. [ABSTRACT FROM AUTHOR]

According to standard experimental practice, researchers randomly assign participants to experimental and control conditions, deeming the experiment “successful” if the means of the two conditions differ in the hypothesized direction. Even for complex experiments, with many conditions, success generally depends on a comparison or contrast of means across conditions. Because the experimental manipulation may change the shape of the distribution, we show that a difference in means, even if large and in the hypothesized direction, does not necessarily indicate the success of the experiment. To make this determination, it also is necessary to compute location statistics. It is possible for means to change but for locations not to change, for means not to change but for locations to change, and for mean differences and location differences to be in opposite directions. Therefore, typical research that depends on differences between means across conditions, cannot be trusted in the absence of location statistics. For similar reasons, nor can standard deviations be trusted without scale statistics. Therefore, we take the radical step of arguing that all researchers who report means and standard deviations, also should be required to report corresponding location and scale statistics. [ABSTRACT FROM AUTHOR]

Mode conversion in differential lines paired with serpentine in PCB layouts of mobile electronic devices is investigated. Different shapes and dimensions are analyzed and design of experiments based on Response Surface Model is used to study the sensitivity of various design parameters to both signal integrity and electromagnetic interference. It is found that mode conversion is negatively affected by the numbers of meanders, the length of bends and their angle. Design guidelines are provided and an alternative shape named trombone is proposed as possible solution to minimize the mode conversion while maximizing the skew matching and reducing the routing area. More than 10 dB of reduction in common mode noise is achieved in a broadband frequency range 0–10 GHz for most of the cases studied. [ABSTRACT FROM AUTHOR]

1. Parents often face an investment trade-off between either producing many small or fewer large offspring. When environments vary predictably, the fittest parental solution matches available resources by varying only number of offspring and never optimal individual size. However when mismatches occur often between parental expectations and true resource levels, dynamic models like multifaceted parental investment (MFPI) and parental optimism (PO) both predict offspring size can vary significantly. MFPI is a "realist" strategy: parents assume future environments of average richness. When resources exceed expectations and it is too late to add more offspring, the best-case solution increases investment per individual. Brood size distributions therefore track the degree of mismatch from right-skewed around an optimal size (slight underestimation of resources) to left-skewed around a maximal size (gross underestimation). Conversely, PO is an "optimist" strategy: parents assume maximally good resource futures and match numbers to that situation. Normal or lean years do not affect "core" brood as costs primarily fall on excess "marginal" siblings who die or experience stunted growth (producing leftskewed distributions). 2. Investment patterns supportive of both MFPI and PO models have been observed in nature, but studies that directly manipulate food resources to test predictions are lacking. Ant colonies produce many offspring per reproductive cycle and are amenable to experimental manipulation in ways that can differentiate between MFPI and PO investment strategies. 3. Colonies in a natural population of a harvester ant (Pogonomyrmex salinus) were protein-supplemented over 2 years, and mature sexual offspring were collected annually prior to their nuptial flight. 4. Several results support either MFPI or PO in terms of patterns in offspring size distributions and how protein differentially affected male and female production. Unpredicted by either model, however, is that supplementation affected distributions more strongly across years than within (e.g., small females are significantly rarer in the year after colonies receive protein). 5. Parental investment strategies in P. salinus vary dynamically across years and conditions. Finding that past conditions can more strongly affect reproductive decisions than current ones, however, is not addressed by models of parental investment. [ABSTRACT FROM AUTHOR]

This study numerically investigated the effects of the skew angle on cavitation and the induced low-frequency pressure fluctuations. The numerical results compare well with available experimental data. The skew angle significantly impacts the cavitation dynamics as well as the pressure fluctuations. As the skew angle increases, the dominant cavity type gradually changes from sheet cavitation to tip vortex cavitation and the cavitation on the blade passing through the wake flow is delayed. Fast Fourier Transforms combined with Wavelet Transforms were applied to explore the relationship between the cavity volume acceleration and pressure fluctuations for various skew angles. The low-frequency pressure fluctuations around the propeller are mainly related to the first blade passing frequency (BPF) and its harmonics. The sheet cavity collapse significantly enhances the interaction of the low BPF components, while the tip vortex cavity collapse has the opposite effect. In addition, large skew angles weaken the interaction of the low BPF components which reduces the low-frequency pressure fluctuations. • Cavitating flow around four marine propellers with various skew angles in the non-uniform wake is numerically investigated. • The effects of the skew angle on cavitation dynamics and induced low-frequency pressure fluctuations are studied. • The correlation between transient cavity characteristics and low-frequency pressure fluctuation components is analyzed. [ABSTRACT FROM AUTHOR]

A new measurement method is proposed for identifying small differences between the relative permittivity of data wires of a twisted pair used in high-data-rate USB cables with <1% uncertainty. This method can also detect small variations in the cross section of the insulated wires. Both the variations are the root causes of the differential mode to common-mode conversion, skew, and possibly electromagnetic interference. The method is based on forming a coaxial structure around the insulated wire under test using metals with low melting points, such as Field’s metal or mercury. Using time-domain reflectometry and knowing the exact length of the structure, the dielectric constant can be derived from the propagation delay measurement. The local cross-sectional variations are detected by observing local impedance variations. Two examples are provided to verify the method and illustrate how to use the method to determine the dominant sources of skew. [ABSTRACT FROM PUBLISHER]

In this paper, we analyze the interbar current taking into account of the contact resistance between the secondary conductor and the steel sheets of squirrel-cage induction motors using the 3-D parallel finite element method. As a result, the effects of the contact resistance on the interbar current are clarified. [ABSTRACT FROM AUTHOR]

Older adults are disproportionately targeted by fraud schemes that advertise unlikely but large returns (positively skewed risks). We examined adult age differences in choice and neural activity as individuals considered risky gambles. Gambles were symmetric (50% chance of modest win or loss), positively skewed (25% chance of large gain), or negatively skewed (25% chance of large loss). The willingness to accept positively skewed relative to symmetric gambles increased with age, and this effect replicated in an independent behavioral study. Whole-brain functional magnetic resonance imaging analyses comparing positively (vs. negatively) skewed trials revealed that relative to younger adults, older adults showed increased anticipatory activity for negatively skewed gambles but reduced activity for positively skewed gambles in the anterior cingulate and lateral prefrontal regions. Individuals who were more biased toward positively skewed gambles showed increased activity in a network of regions including the nucleus accumbens. These results reveal age biases toward positively skewed gambles and age differences in corticostriatal regions during skewed risk-taking, and have implications for identifying financial decision biases across adulthood. [ABSTRACT FROM AUTHOR]

We investigate the effect of a skewed permanent magnet (PM) with overhang on the axial unbalanced magnetic force (UMF) of a PM motor, especially in the presence of static and dynamic eccentricities of a rotor. We derive the mathematical equations of the axial UMF acting on PM motor due to the skewed PM with overhang and rotor eccentricities. We develop a 3-D finite-element model of the PM motor, not only to verify the frequency components of the proposed equations but also to determine the amplitude of the axial UMF. Further, we develop an experimental setup to measure the axial UMF caused by a skewed PM with overhang and rotor eccentricities. We confirm that the skewed PM with overhang generates an axial UMF with the harmonic of the least common multiple of pole and slot numbers. In addition, the static and dynamic eccentricities with the interaction of the skewed PM and overhang generate the axial UMF with the pole harmonics and slot harmonics, respectively. [ABSTRACT FROM AUTHOR]

This article shows that the axioms of a skew monoidal category are independent and that its unit is unique up to a unique isomorphism together with an analogue of this result for monoidal functors between skew monoidal categories. It is also noted that these results carry over to skew monoidales before some benefits of certain extra structure on the unit maps of a skew monoidal category are discussed. [ABSTRACT FROM AUTHOR]

The effects of support in steel bridges can present significant challenges during construction. The tendency of the girder to twist or layover during the placement of the deck can present a particularly challenging problem regarding detailing the cross-frames that provide bracing to the steel girders. There are generally three alternatives regarding the detailing for the cross-frames to achieve an approximate plumb condition of the webs: 1) detailing for no load fit, 2) detailing for steel dead load fit, or 3) detailing for total dead load fit. In the past, different detailing methods have been investigated to identify and compare structural responses affected by the detailing methods. However, the use of wrong camber diagrams in these studies lead to erroneous calculations of structural responses for total dead load fit. The objectives of this paper are: 1) to identify structural responses that are affected by different detailing methods, and 2) to compare different detailing methods for straight skewed I-girder bridges using correct cambers. Different structural responses affected by detailing methods, henceforth called lack-of-fit effects, are discussed for each method. It has been shown that line girder analysis cambers should be used instead of 2D grid analysis cambers to simulate lack-of-fit for the final fit detailing method. It has been found that lack-of-fit effects for the final fit detailing method at steel dead load stage are equal and opposite to the lack-of-fit effects for the erected fit detailing method at total dead load stage. [ABSTRACT FROM AUTHOR]

A coaxial turbine under skew with significant rotor spacing has the potential for increased power output compared to a flow-aligned turbine due to a portion of the downstream rotor experiencing freestream velocity, referred to as a fresh flow region. A lab-scale prototype was designed and built to investigate the skew-to-power relationship of a coaxial turbine system as it compared to a blade element momentum theory model with multiple, sheared streamtubes representing the downstream rotor fresh flow region. The inclusion of the downstream rotor fresh flow region in the theoretical analysis is compared to the experimental data. The results support that the torque and power performance of the downstream rotor and overall skewed coaxial turbine system are predicted more accurately. [Display omitted] • BEMT for tethered, coaxial, counter-rotating turbines in skewed equilibrium is developed. • The fresh flow region is the portion of the downstream rotor where freestream velocity occurs. • The fresh flow region is modeled as a composite actuator disc with multiple velocity shears. • Experimental results compared to the modeled fresh flow region improved prediction accuracy. [ABSTRACT FROM AUTHOR]

Developing probabilistic seismic demand models is a key element in seismic risk assessment of structures such as bridges. Identifying the influential parameters related to the seismic response of a structure is a crucial step towards evaluating its seismic vulnerability. Most of the past related sensitivity studies have focused on regular bridges with typical configurations, although observed damage from past earthquakes affirms that compared to regular bridges, those with irregularities or geometric inconsistencies in the configuration are more susceptible to noticeable damage. In this paper, using state of the art statistical methodology, the influence of various parameters on the resulting probabilistic seismic demand is investigated. This study concentrates on concrete bridges including three geometric irregularity types: (i) skew angle, (ii) a frame with unbalanced stiffness, and (iii) tall column heights, and a comprehensive sensitivity of a broad range of probabilistic modeling parameters on the seismic response is assessed. The statistical analysis reveals that the common parameters including ground motion intensity, longitudinal reinforcement ratio, column diameter, number of columns per bent, column height, span length, and concrete compressive strength significantly influence the response of the three studied irregular bridges. The individual influential parameters affecting each class of irregularity are highlighted and discussed. [ABSTRACT FROM AUTHOR]

In this paper, a novel 3-D sub-domain analytical model is developed to determine magnetic flux distribution in single-cage induction machines (IMs) with skewed rotor bars under no-load condition in an effort to more detailed analysis of spatial harmonics. The proposed model, along with an optimization algorithm, is as an alternative solution to finite-element analysis (FEA) in optimizing the geometry of IMs. The analytical method is based on the resolution of 3-D Laplace and Poisson’s equations in cylindrical coordinates using the separation of variables method to calculate the magnetic vector potential for corresponding sub-domain. The proposed model includes the effect of slotting and tooth tips for the stator and rotor slots, which is usually neglected in a 2-D analysis due to the complexity of differential equations. Also, the proposed 3-D model can be used for any slot-pole combination in addition to considering the asymmetrical effect in the axial direction, which is a source of noise, vibration, and excessive losses in IMs. To evaluate the performance of the proposed 3-D analytical model, calculated magnetic-field distribution is compared with the results obtained from the 3-D FEA. [ABSTRACT FROM AUTHOR]

In analyses of polystyrene standards by size-exclusion chromatography for polymers of molecular weight about thirty thousand and higher, the separation improved with decreasing flow-rate is in accord with Giddings observation of transversal diffusion as a factor decreasing the broadening of the band broadening function. The variance of the elution curves is larger than it corresponds to dispersity M ¯ w / M ¯ n and the shape of the elution curves depends on the experimental conditions which suggests that it reflects properties of the band broadening function. The skew and the excess kurtosis of the elution curves increase near the exclusion limit in accord with theoretical prediction for the band broadening function. [ABSTRACT FROM AUTHOR]

Distributed classification in large-scale P2P networks has gained relevance in recent years and support applications like distributed intrusion detection in P2P monitoring environments, online match-making, personalized information retrieval, distributed document classification in a P2P media repository and P2P recommender systems to mention a few. However, classification in a P2P network is a challenging task due to the constraints such as centralization of data is not feasible, scarce communication bandwidth, scalability, synchronization and peer dynamism. Moreover, without considering data distributions and topological scenarios of real world P2P systems, most of the existing distributed classification approaches lack in their predictive and network-cost performance. In this paper, we investigate a collaborative classification method (TRedSVM) based on Support Vector Machines (SVM) in Scale-free P2P networks. In particular, we demonstrate how to construct SVM classifier in real world P2P networks which exhibit inherently skewed distribution of node links and eventually data. The proposed method propagates the most influential instances of SVM models to the vast majority of scarcely connected peers in a controlled way that improves their local classification accuracy and, at the same time, keeps the communication cost low throughout the network. Besides using benchmark Machine Learning data sets for extensive experimental evaluations, we have evaluated the proposed method particularly for music genre classification to exhibit its performance in a real application scenario. Additionally, performance analysis is carried out with respect to centralized approaches, data replication in P2P networks and cost accuracy trade-off. TRedSVM outperforms baseline approaches of model propagation by improving the overall classification performance substantially at the cost of a tolerable increase in communication. [ABSTRACT FROM AUTHOR]

The frame bridge is locating on the circular curve and has large skew angle, the pipeline layout is intensive and complex on the bridge site, to ensure the existing road traffic flow and the railway transportation safety during the old bridge demolition and new bridge jacking period, we carried out the improvement and innovation of the jacking scheme based on the experience of the conventional jacking construction using the technology of combining the side span jacking and mid-span cast-in-place in order to reduce the risk of construction safety, using adding the anti-sliding pile measures to enhance the lateral stability of beam overhead, and taking measures to make the safety transition of the electric column during the construction period and the normal operation period .The practice proves that the operation is simple and applicable. [ABSTRACT FROM AUTHOR]

Transmissions across asynchronous communication channels are subject to delay injection attacks, which can cause an arbitrary number of skews. That is, such attacks can cause an arbitrary number of transmitted signals to arrive after the first signal of the next transmission has arrived. The (common) assumption that despite the delays, all signals from the $i$ th transmission arrive at the decoder before any signal from the (i+2){\text{nd}} transmission arrives is called a no switch assumption. This paper presents a self-synchronizing, zero-latency, zero-error coding scheme that requires no acknowledge and can decode transmissions distorted by an arbitrary number of skews that obey this no switch assumption. The rate associated with the coding scheme provides a lower bound of 0.6942 for the (zero-error) capacity of such a channel. It is further shown that zero-error channel capacity of the channel is upper bounded by 0.7248. Finally, this paper presents bounds on the (zero-error) capacity of a channel for which the number of transmissions that can mix with one another is large. [ABSTRACT FROM AUTHOR]

Clock networks are required to be constructed with adequate safety margins in the skew constraints to operate correctly even under the influence of variations. In this work, a scalable clock scheduler is developed to drive a synthesis framework that constructs useful skew clock trees with large safety margins that are tailored to the tree topology. Sequential elements are clustered early in the topology, if it is impossible provide adequate robustness to variations using only safety margins. Compared to earlier studies, the proposed framework performs the clock scheduling one to two orders of magnitude faster and improves yield and capacitive cost on several synthesized circuits. [ABSTRACT FROM AUTHOR]

An r -fold analogue of the positive semidefinite zero forcing process that is carried out on the r -blowup of a graph is introduced and used to define the fractional positive semidefinite forcing number. Properties of the graph blowup when colored with a fractional positive semidefinite forcing set are examined and used to define a three-color forcing game that directly computes the fractional positive semidefinite forcing number of a graph. We develop a fractional parameter based on the standard zero forcing process and it is shown that this parameter is exactly the skew zero forcing number with a three-color approach. This approach and an algorithm are used to characterize graphs whose skew zero forcing number equals zero. [ABSTRACT FROM AUTHOR]

Magnetic gears are able to transmit torque between an input and an output shaft without mechanical contact. As for electrical drives, torque density, acoustic noise, and torque ripple are of primary concern. This paper describes the influence of the pole numbers on the radial forces and the cogging torques. We show how continuous and discrete skewing can suppress torque harmonics effectively. Further, we investigated different simulation modes for magnetic gears using finite-element software. A multiobjective optimization was conducted to find a Pareto-optimal magnetic gear, whose cogging torque was minimized by skewing one rotor. Finally, we present a prototype with a gear ratio of 1:21, and compare finite-element results with the measurements of unskewed and skewed magnetic gears. [ABSTRACT FROM PUBLISHER]

The objective of this work is to investigate the influence of skew on the added mass and damping matrices, which govern the vibration characteristics of the propulsion system. A 3-D curved lifting line model is developed to predict the propeller performance, and the model is validated with experimental measurements of the open water performance for the classic DTMB propellers 4381–4384 with varying skew. To compute the added mass and damping matrices of skewed propellers, the 3-D curved lifting line model is coupled with 2-D unsteady thin foil theory. The added mass and damping predictions are validated with published numerical data and empirical equations for a propeller with moderate skew. The added mass and damping characteristics of DTMB propellers 4381–4384 are calculated, and the influence of skew on these characteristics is discussed. The results show that skew affects the coupled motions with the sway, heave, pitch, and yaw components of the added mass and damping matrices, while the influence on the surge and roll components is negligible. [ABSTRACT FROM AUTHOR]

We present a simple, message-optimal algorithm for maintaining a random sample from a large data stream whose input elements are distributed across multiple sites that communicate via a central coordinator. At any point in time, the set of elements held by the coordinator represent a uniform random sample from the set of all the elements observed so far. When compared with prior work, our algorithms asymptotically improve the total number of messages sent in the system. We present a matching lower bound, showing that our protocol sends the optimal number of messages up to a constant factor with large probability. We also consider the important case when the distribution of elements across different sites is non-uniform, and show that for such inputs, our algorithm significantly outperforms prior solutions. [ABSTRACT FROM PUBLISHER]

Research on the influence of tsunamis on bridges has been based almost exclusively on the results of field surveys and of twodimensional analysis. Although these analyses can provide estimates of forces and moments on the structure, they do not account for threedimensional (3D) phenomena, such as channelization, or geometric effects, such as bridge skew. Using a 3D computational fluid dynamics approach, this work analyzes the temporal and spatial dynamics of a bore-type tsunami loading on a model bridge and shows how the skew angle of the bridge relative to the incoming wave can affect the loading history. The analyses found that, unlike a bridge without skew, (1) the bore impact forces on the skewed deck do not all occur at the same time; (2) the skewed bridge is subjected to a force perpendicular to its abutments, which could lead to unseating; and (3) the skewed bridge is subjected to pitching and spinning moments. These effects combine to lead to increased horizontal reactions in the substructure components nearest the incoming wave. The vertical reactions were relatively insensitive to skew angle. [ABSTRACT FROM AUTHOR]

Currently available behavioral assays to quantify normal cold sensitivity, cold hypersensitivity and cold hyperalgesia in mice have betimes created conflicting results in the literature. Some only capture a limited spectrum of thermal experiences, others are prone to experimenter bias or are not sensitive enough to detect the contribution of ion channels to cold sensing because in mice smaller alterations in cold nociception do not manifest as frank behavioral changes. To overcome current limitations we have designed a novel device that is automated, provides a high degree of freedom, i.e. thermal choice, and eliminates experimenter bias. The device represents a thermal gradient assay designed as a circular running track. It allows discerning exploratory behavior from thermal selection behavior and provides increased accuracy by providing measured values in duplicate and by removing edge artifacts. Our custom-designed automated offline analysis by a blob detection algorithm is devoid of movement artifacts, removes light reflection artifacts and provides an internal quality control parameter which we validated. The assay delivers discrete information on a large range of parameters extracted from the occupancy of thermally defined zones such as preference temperature and skew of the distribution. We demonstrate that the assay allows increasingly accurate phenotyping of thermal sensitivity in transgenic mice by disclosing yet unrecognized details on the phenotypes of TRPM8-, TRPA1- and TRPM8/A1-deficient mice. [ABSTRACT FROM AUTHOR]

This paper focuses on the 3-D effects associated with rotor step-skews performed in permanent magnet-assisted synchronous reluctance machines (PMA SynRMs). It analyzes and quantifies these effects via comparisons between 2-D and 3-D finite-element analyses (FEA) of skewed and unskewed machines. The 3-D phenomena manifested in the skewed PMA SynRM are identified into end-effects and axial interactions between skewed steps, and their influence on its electromagnetic performance is examined under load and no-load conditions. This paper exemplifies the significance of the skew-associated 3-D effects, which can result in considerable decrease of the back electromotive force and a substantially increased electromagnetic torque ripple. It, thereby, highlights the inability of the typically employed multislice 2-D FEA or other existing 2-D-based modeling techniques in taking their influence into account. The validity of the findings is experimentally verified with measurements acquired from a prototype PMA SynRM using skewed and unskewed shafts in the rotor. [ABSTRACT FROM AUTHOR]