Understanding Timing Error Characteristics From Overclocked Systolic Multiply-Accumulate Arrays in FPGAs

Artificial Intelligence (AI) is one of the biggest fields of research for computer hardware right now. Hardware accelerators are chips (such as graphics cards) that are purpose built to be the best at a specific type of operation. AI hardware accelerators are a growing field of research. Part of hardware in general is a digital clock that controls the pace at which computations occur. If this clock runs too quickly, the hardware won\u27t have enough time to finish its computation. We call that a timing error. This paper focuses on studying the characteristics of timing errors in a small custom AI hardware accelerator design on a device called an FPGA (Field Programmable Gate Array). An FPGA is a sort of re-configurable hardware platform that allows for much cheaper prototyping than manufacturing a custom design in a physical chip (which would cost millions of dollars at least). By running the experiment on exactly one FPGA board, the experiment will control for any microscopic flaws in that specific board (called Process Variation or PV). Without this control, the small differences in computation that are observed could be attributed to PV. The experiment consists of loading the design onto the FPGA and sweeping the clock from its normal operating frequency up to more than 3× the normal frequency the design is intended to run at. During each sweep, the outputs of the computation are captured for later analysis

Stability of the Submillimeter Brightness of the Atmosphere Above Mauna Kea, Chajnantor and the South Pole

The summit of Mauna Kea in Hawaii, the area near Cerro Chajnantor in Chile, and the South Pole are sites of large millimeter or submillimeter wavelength telescopes. We have placed 860 GHz sky brightness monitors at all three sites and present a comparative study of the measured submillimeter brightness due to atmospheric thermal emission. We report the stability of that quantity at each site.Comment: 6 figure

Finite difference time domain calculation of transients in antennas with nonlinear loads

In this paper transient fields for antennas with more general geometries are calculated directly using Finite Difference Time Domain methods. In each FDTD cell which contains a nonlinear load, a nonlinear equation is solved at each time step. As a test case the transient current in a long dipole antenna with a nonlinear load excited by a pulsed plane wave is computed using this approach. The results agree well with both calculated and measured results previously published. The approach given here extends the applicability of the FDTD method to problems involving scattering from targets including nonlinear loads and materials, and to coupling between antennas containing nonlinear loads. It may also be extended to propagation through nonlinear materials

Reconciling scientific reality with realpolitik: moving beyond carbon pricing to TEQs – an integrated, economy-wide emissions cap

<div><p>This article considers why price-based frameworks may be inherently unsuitable for delivering unprecedented global emissions reductions while retaining the necessary public and political support, and argues that it is time to instead draw on quantity-based mechanisms such as TEQs (tradable energy quotas).</p><p>TEQs is a climate policy framework combining a hard cap on emissions with the use of market mechanisms to distribute quotas beneath that cap.</p><p>The significant international research into TEQs is summarized, including a 2008 UK government feasibility study, which concluded that the scheme was “ahead of its time.” TEQs would cover all sectors within a national economy, including households, and findings suggest it could act as a catalyst for the socio-technical transitions required to maximize wellbeing under a tightening cap, while generating national common purpose toward innovative energy demand reductions.</p><p>Finally, there are reflections on the role that the carbon management community can play in further developing TEQs and reducing the rift between what climate science calls for and what politics is delivering.</p></div

A simple approach to estimating three-dimensional supercavitating flow fields

A simple method is formulated for predicting three-dimensional supercavitating flow behind cavitators subject to gravitational acceleration and motion of the cavitator. The method applies slenderbody theory in the context of matched asymptotic expansions to pose an inner problem for the cavity evolution downstream from the locus of cavity detachment. This inner problem is solved by means of a coupled set of equations for the Fourier coefficients characterizing the cavity radius and the velocity potential as a function of downstream location and circumferential location, thus resulting in a two-dimensional multipole solution at each station. For the lowestorder term in the Fourier expansion, it is necessary to match the parabolic inner solution to a fully elliptic outer solution. This step allows the application of any one of a number of methods to solve the axisymmetric problem, which serves as the base solution that is perturbed by the three-dimensional effects. The method is an attempt to formalize the Logvinovich principle of independent cavity section evolution. Results flow past a circular disk cavitator are presented for severalvalues of the cavity Froude number.http://deepblue.lib.umich.edu/bitstream/2027.42/84318/1/CAV2009-final145.pd

Space Plasma Ion Processing of the Lunar Soil: Modeling of Radiation-Damaged Rim Widths on Lunar Grains

Chemically and microstructurally complex altered rims around grains in the finest size fraction (<20 micron) of the lunar regolith are the result of multi-stage processes involving both solar ion radiation damage and nanoscale deposition of impact or sputter-derived vapors. The formation of the rims is an important part of the space weathering process, and is closely linked to key changes in optical reflectance and other bulk properties of the lunar surface. Recent application of field-emission scanning transmission electron microscope techniques, including energy dispersive X-ray spectral imaging, is making it easier to unravel the "nano-stratigraphy" of grain rims, and to delineate the portions of rims that represent Radiation-Amorphized (RA) host grain from overlying amorphous material that represents vapor/sputter deposits. For the portion of rims formed by host grain amorphization (henceforth called RA rims), we have been investigating the feasibility of using Monte Carlo-type ion-atom collision models, combined with experimental ion irradiation data, to derive predictive numerical models linking the width of RA rims to the grain s integrated solar ion radiation exposure time

Factors That Influence Mathematical Creativity

Creativity is a psychological construct that has gained research popularity (Akgul & Kaveci, 2016), however it remains a challenging one to define. The variety of definitions promulgated to understand creativity hints at the complexity of the mental process. Furthermore, as a subset of creativity, domain-specific mathematical creativity has also garnered a variety of definitions. The transdisciplinary research on creativity (Sriraman & Haavold, 2017) is seminal in this world of fast-paced innovation, invention, solution, and synthesis. Considering every human being with at least average cognitive abilities possesses the ability to think creatively (Baran, 2011), developing students’ creative talents and abilities must be high on a list of educational priorities. Much of the literature surrounding mathematical creative thinking is centered on trying to quantify an individual’s creative thinking abilities. There have also been studies conducted that enabled researchers to describe various traits and demonstrate multiple levels of creativity. The basis of this work will be to synthesize the characteristics of mathematical creativity, analyze the impact of specific teaching approaches on mathematical creativity, and examine the relationship between student affect and mathematical creativity