Multi-patch discontinuous Galerkin isogeometric analysis for wave propagation: explicit time-stepping and efficient mass matrix inversion

We present a class of spline finite element methods for time-domain wave propagation which are particularly amenable to explicit time-stepping. The proposed methods utilize a discontinuous Galerkin discretization to enforce continuity of the solution field across geometric patches in a multi-patch setting, which yields a mass matrix with convenient block diagonal structure. Over each patch, we show how to accurately and efficiently invert mass matrices in the presence of curved geometries by using a weight-adjusted approximation of the mass matrix inverse. This approximation restores a tensor product structure while retaining provable high order accuracy and semi-discrete energy stability. We also estimate the maximum stable timestep for spline-based finite elements and show that the use of spline spaces result in less stringent CFL restrictions than equivalent piecewise continuous or discontinuous finite element spaces. Finally, we explore the use of optimal knot vectors based on L2 n-widths. We show how the use of optimal knot vectors can improve both approximation properties and the maximum stable timestep, and present a simple heuristic method for approximating optimal knot positions. Numerical experiments confirm the accuracy and stability of the proposed methods

Here Comes the Sunburst: Measuring and Visualizing Scholarly Impact

Our ARL institution partnered with a new service (PlumX) to track, measure, and visualize faculty scholarly impact. In a pilot project, both traditional and emerging measures of scholarly impact were collected for 32 researchers. The presenters will chronicle the data management and enhancements applied, including utilizing content from our institutional repository, importing and enriching metadata, and using an intranet to organize work and collaborate with colleagues. Results will assist faculty and those who work with them to identify strengths and weaknesses of scholarly impact and where to focus efforts to increase research visibility

ExaGridPF: A Parallel Power Flow Solver for Transmission and Unbalanced Distribution Systems

This paper investigates parallelization strategies for solving power flow problems in both transmission and unbalanced, three-phase distribution systems by developing a scalable power flow solver, ExaGridPF, which is compatible with existing high-performance computing platforms. Newton-Raphson (NR) and Newton-Krylov (NK) algorithms have been implemented to verify the performance improvement over both standard IEEE test cases and synthesized grid topologies. For three-phase, unbalanced system, we adapt the current injection method (CIM) to model the power flow and utilize SuperLU to parallelize the computing load across multiple threads. The experimental results indicate that more than 5 times speedup ratio can be achieved for synthesized large-scale transmission topologies, and significant efficiency improvements are observed over existing methods for the distribution networks

Respect for people : looking at KPI’s through ‘younger eyes’!

Movement for Innovation (M4I) is partly aimed at delivering targets set by the Egan (1998) report. An initiative under this programme is the ‘Respect for People’ (RFP) working group. This body published its first formal report entitled: A Commitment to People: ‘Our Biggest Asset’ (2000), and challenged construction to respect its workforce. Failure to do so will result in firms being unable to recruit and retain the best talent in the workforce – currently a 'hot topic' in attracting school-leavers into the construction trades. Construction is thought to have harsh conditions of safety and welfare, with poor prospects - ideas that actively discourage many school-leavers. To combat this ‘image’ problem, the RFP Working Group are piloting a toolkit which can be used to measure and monitor safety and welfare in order to benchmark their performance against industry best practice. This paper uses an adapted version of this toolkit. Building apprentices in Scottish Further Education Colleges were asked their opinions on ‘site life’ and to complete a questionnaire. The results provide an insight into current thinking and expectations of the 'future' of trade apprentices today. The findings are significant to groups needing input from construction's youth (Construction Industry Training Board (CITB) and M4I). Additionally this paper is of value to academics interested in human aspects and trends in UK construction

Skin thickness of the anterior, anteromedial, and anterolateral thigh: a cadaveric study for split-skin graft donor sites

Background: The depth of graft harvest and the residual dermis available for reepithelization primarily influence the healing of split-skin graft donor sites. When the thigh region is chosen, the authors hypothesize based on thickness measurements that the anterolateral region is the optimal donor site. Methods: Full-thickness skin specimens were sampled from the anteromedial, anterior, and anterolateral regions of human cadavers. Skin specimens were cut perpendicularly with a custom-made precision apparatus to avoid the overestimation of thickness measurements. The combined epidermal and dermal thicknesses (overall skin thickness) were measured using a digital calliper. The specimens were histologically stained to visualize their basement membrane, and microscopy images were captured. Since the epidermal thickness varies across the specimen, a stereological method was used to eliminate observer bias. Results: Epidermal thickness represented 2.5% to 9.9% of the overall skin thickness. There was a significant difference in epidermal thickness from one region to another (P<0.05). The anterolateral thigh region had the most consistent and highest mean epidermal thickness (60±3.2 µm). We observed that overall skin thickness increased laterally from the anteromedial region to the anterior and anterolateral regions of the thigh. The overall skin thickness measured 1,032±435 µm in the anteromedial region compared to 1,220±257 µm in the anterolateral region. Conclusions: Based on skin thickness measurements, the anterolateral thigh had the thickest epidermal and dermal layers. We suggest that the anterolateral thigh region is the optimal donor site for split-skin graft harvests from the thigh

Market Response to Two Alternative Packages for U.S. No. 2 Grapefruit

Packages, U.S. No. 2 Grapefruits, Grapefruit, Alternatives, Crop Production/Industries, Food Consumption/Nutrition/Food Safety, Marketing,

One-dimensional wave equations defined by fractal Laplacians

We study one-dimensional wave equations defined by a class of fractal Laplacians. These Laplacians are defined by fractal measures generated by iterated function systems with overlaps, such as the well-known infinite Bernoulli convolution associated with the golden ratio and the 3-fold convolution of the Cantor measure. The iterated function systems defining these measures do not satisfy the post-critically finite condition or the open set condition. By using second-order self-similar identities introduced by Strichartz et al., we discretize the equations and use the finite element and central difference methods to obtain numerical approximations to the weak solutions. We prove that the numerical solutions converge to the weak solution, and obtain estimates for the rate of convergence

A Comprehensive Survey of Deep Learning in Remote Sensing: Theories, Tools and Challenges for the Community

In recent years, deep learning (DL), a re-branding of neural networks (NNs), has risen to the top in numerous areas, namely computer vision (CV), speech recognition, natural language processing, etc. Whereas remote sensing (RS) possesses a number of unique challenges, primarily related to sensors and applications, inevitably RS draws from many of the same theories as CV; e.g., statistics, fusion, and machine learning, to name a few. This means that the RS community should be aware of, if not at the leading edge of, of advancements like DL. Herein, we provide the most comprehensive survey of state-of-the-art RS DL research. We also review recent new developments in the DL field that can be used in DL for RS. Namely, we focus on theories, tools and challenges for the RS community. Specifically, we focus on unsolved challenges and opportunities as it relates to (i) inadequate data sets, (ii) human-understandable solutions for modelling physical phenomena, (iii) Big Data, (iv) non-traditional heterogeneous data sources, (v) DL architectures and learning algorithms for spectral, spatial and temporal data, (vi) transfer learning, (vii) an improved theoretical understanding of DL systems, (viii) high barriers to entry, and (ix) training and optimizing the DL.Comment: 64 pages, 411 references. To appear in Journal of Applied Remote Sensin