A Hybrid Radial Basis Function-Pseudospectral Method for Thermal Convection in a 3-D Spherical Shell

A novel hybrid spectral method that combines radial basis function (RBF) and Chebyshev pseudospectral methods in a “2 + 1” approach is presented for numerically simulating thermal convection in a 3‐D spherical shell. This is the first study to apply RBFs to a full 3‐D physical model in spherical geometry. In addition to being spectrally accurate, RBFs are not defined in terms of any surface‐based coordinate system such as spherical coordinates. As a result, when used in the lateral directions, as in this study, they completely circumvent the pole issue with the further advantage that nodes can be “scattered” over the surface of a sphere. In the radial direction, Chebyshev polynomials are used, which are also spectrally accurate and provide the necessary clustering near the boundaries to resolve boundary layers. Applications of this new hybrid methodology are given to the problem of convection in the Earth’s mantle, which is modeled by a Boussinesq fluid at infinite Prandtl number. To see whether this numerical technique warrants further investigation, the study limits itself to an isoviscous mantle. Benchmark comparisons are presented with other currently used mantle convection codes for Rayleigh number (Ra) 7 × 103 and 105. Results from a Ra = 106 simulation are also given. The algorithmic simplicity of the code (mostly due to RBFs) allows it to be written in less than 400 lines of MATLAB and run on a single workstation. We find that our method is very competitive with those currently used in the literature

What is the Connection Between Issues, Bugs, and Enhancements? (Lessons Learned from 800+ Software Projects)

Agile teams juggle multiple tasks so professionals are often assigned to multiple projects, especially in service organizations that monitor and maintain a large suite of software for a large user base. If we could predict changes in project conditions changes, then managers could better adjust the staff allocated to those projects.This paper builds such a predictor using data from 832 open source and proprietary applications. Using a time series analysis of the last 4 months of issues, we can forecast how many bug reports and enhancement requests will be generated next month. The forecasts made in this way only require a frequency count of this issue reports (and do not require an historical record of bugs found in the project). That is, this kind of predictive model is very easy to deploy within a project. We hence strongly recommend this method for forecasting future issues, enhancements, and bugs in a project.Comment: Accepted to 2018 International Conference on Software Engineering, at the software engineering in practice track. 10 pages, 10 figure

Modelling of viscoelastic plume-lithosphere interaction using the adaptive multilevel wavelet collocation method

Modelling of mantle flows with sharp viscosity contrasts in a viscoelastic medium is a challenging computational problem in geodynamics because of its multiple-scale nature in space and time. We have employed a recently developed adaptive multilevel wavelet collocation algorithm to study the dynamics of a small rising diapir interacting with a stiff lithosphere in a Maxwell viscoelastic mantle. In this kinematic model we have prescribed the upward velocity of the diapir and then we need to integrate in time onlythe momentum equation governing the temporal evolution of the pressure, stress andvelocity components, which together constitute a sixth-order system in time. The total number of collocation points did not exceed 104, compared to more than 106 gridpoints using conventional evenly spaced grid methods. The viscosity of the diapir is10−4 times lower than that of the surrounding mantle, while the viscosity of the thinlithosphere, about 5-10 per cent of the entire layer depth, is 104-108 times stiffer than the ambient mantle. Our results demonstrate the efficacy of wavelets to capture thesharp gradients of the stress and pressure fields developed in the diapiric impingement process. The interaction of the viscoelastic lithosphere with therisingviscoelastic diapir results in the localization of stress within the lithosphere. The magnitude of the stress fields can reach around 100-300 MPa. Our simple kinematic model shows clearly that viscoelasticity canpotentially play an important role in the dynamics of thelithosphere, especially concerning the potential severage of the lithosphere by mantle upwelling

Target recognitions in multiple camera CCTV using colour constancy

People tracking using colour feature in crowded scene through CCTV network have been a popular and at the same time a very difficult topic in computer vision. It is mainly because of the difficulty for the acquisition of intrinsic signatures of targets from a single view of the scene. Many factors, such as variable illumination conditions and viewing angles, will induce illusive modification of intrinsic signatures of targets. The objective of this paper is to verify if colour constancy (CC) approach really helps people tracking in CCTV network system. We have testified a number of CC algorithms together with various colour descriptors, to assess the efficiencies of people recognitions from real multi-camera i-LIDS data set via Receiver Operating Characteristics (ROC). It is found that when CC is applied together with some form of colour restoration mechanisms such as colour transfer, the recognition performance can be improved by at least a factor of two. An elementary luminance based CC coupled with a pixel based colour transfer algorithm, together with experimental results are reported in the present paper

Electrolyte-Sensing Transistor Decals Enabled by Ultrathin Microbial Nanocellulose

We report an ultra-thin electronic decal that can simultaneously collect, transmit and interrogate a bio-fluid. The described technology effectively integrates a thin-film organic electrochemical transistor (sensing component) with an ultrathin microbial nanocellulose wicking membrane (sample handling component). As far as we are aware, OECTs have not been integrated in thin, permeable membrane substrates for epidermal electronics. The design of the biocompatible decal allows for the physical isolation of the electronics from the human body while enabling efficient bio-fluid delivery to the transistor via vertical wicking. High currents and ON-OFF ratios were achieved, with sensitivity as low as 1 mg·L−1

Impact of Non Steroidal Anti-Inflammatory Drug Administration Pre- or Post-Resistance Training on Bone

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) have been shown to suppress bone formation when administered before, but not if administered after, an acute bout of mechanical load. The effects of giving NSAIDs pre- and post-resistance training over multiple training sessions are not yet well defined. Therefore, the aim of this study was to elucidate the effects of NSAIDs when administered pre and post simulated resistance training (SRT) in a small animal model. We hypothesize that gains in bone mass and increased bone size will be diminished in adult rats given ibuprofen before each training session, but will be enhanced if ibuprofen is given after each exercise bout. Methods: Fifteen 5-month-old virgin female Sprague-Dawley rats completed 9 SRT sessions at 75% peak isometric strength for 4 sets of 5 repetitions; each contraction included 1 sec isometric + 1 sec eccentric contraction. Animals were blocked assigned by body weight to one of three groups: (1) ibuprofen (30mg/kg) before exercise, placebo after (I:P)(n=4), (2) placebo before exercise, ibuprofen after (P:I)(n=5) and (3) placebo before exercise, placebo after (P:P)(n=6). In vivo pQCT scans measured changes in total volumetric bone mineral density (vBMD), cancellous vBMD, and total area at the proximal tibia, and cortical vBMD, cortical bone mineral content (BMC) and total area at midshaft tibia from days -7 and 21. Body weights were measured at days 4, 14 and 21. Results: There were no significant changes in body weight over the course of the study (P:P -2.6%, I:P -2.3% & P:I -3.8%, day 21 vs day 4). Furthermore, there was no significant difference across time in midshaft cortical vBMD, but the P:I group did exhibit a significantly different response in cortical vBMD when normalized to body weight (+5.1%) (p\u3c .05) compared to I:P (-1.4%) and P:P (-0.3%). There were no differences among groups for change in cancellous vBMD, total vBMD and total area at the proximal region, as well as cortical BMC and total area at midshaft tibia. Conclusion: These data are preliminary but suggest that ibuprofen given after exercise may produce additional gains in cortical bone following resistance training; we have no evidence thus far that ibuprofen taken before exercise has any effect. Supported by Huffines Institute of Sports Medicine and Human Performance, Texas A&M University

Time-Dependent Density Functional Theory for Open Quantum Systems with Unitary Propagation

We extend the Runge-Gross theorem for a very general class of open quantum systems under weak assumptions about the nature of the bath and its coupling to the system. We show that for Kohn-Sham (KS) time-dependent density functional theory, it is possible to rigorously include the effects of the environment within a bath functional in the KS potential. A Markovian bath functional inspired by the theory of nonlinear Schrödinger equations is suggested, which can be readily implemented in currently existing real-time codes. Finally, calculations on a helium model system are presented.Chemistry and Chemical Biolog