197 research outputs found
Demeter goes skydiving
No full textA part of the "cuRRents" Canadian literature series.What if Demeter, the timeless fertility goddess of ancient Greek myth, slipped through a crack into the twenty-first century, shook off her ankle bracelets, corn tassels, and garlands, and began a tour of our improbable culture? Award-winning poet Susan McCaslin exercises the profound mother-daughter trauma forged in the Demeter-Persephone myth with unapologetic modernity. This sequence takes on a novel life all its own: Hades steals away the maiden into a cult/culture of distorted body image, addiction, high anxiety, and rampant consumerism. Mother Demeter must negotiate this alien world of health clubs, paparazzi, and so-called reality shows locked in spiritual winter. McCaslin's lyrics are by turns profound, hilarious, and devastating as she journeys to the heart of a mother's love for her daughter. Here is poetry that seeks ties to the past inside the present, poetry that speaks to us all. --From publisher description.poetryCanadian literatur
Logarithmic L p Bounds for Maximal Directional Singular Integrals in the Plane
No full textLet K be a Calderón-Zygmund convolution kernel on R. We discuss the L p -boundedness of the maximal directional singular integral T V f(x)= sup v ε V | ∫R f(x+t v) K(t)dt|where V is a finite set of N directions. Logarithmic bounds (for 2≤p<∞) are established for a set V of arbitrary structure. Sharp bounds are proved for lacunary and Vargas sets of directions. The latter include the case of uniformly distributed directions and the finite truncations of the Cantor set. We make use of both classical harmonic analysis methods and product-BMO based time-frequency analysis techniques. As a further application of the latter, we derive an L p almost orthogonality principle for Fourier restrictions to cones. © 2012 Mathematica Josephina, Inc
Validation of electron density and temperature observed by DEMETER
No full textMeasuring electron density (Ne) and temperature (Te) using a DC Langmuir probe in the ionosphere is very often degraded by the electrode contamination. In order to examine the accuracy of DEMETER observations, we compared DEMETER Ne and Te with several other satellites observations and IRI2012 as reference data. DEMETER Ne and Te show well-known dependencies on the solar irradiance except for the range of F10.7 > 100. However, DEMETER Ne are about 70% lower than those of IRI in day time data and its solar irradiance dependency is consistent with the reference data in night time data. It was confirmed that the negative slope appears in deep solar minimum solar cycle 23/24. DEMETER Te are higher than IRI data by 500-1500 K in day time and by 800 K in night time. The relation between Ne and Te is well defined by a negative slope both in DEMETER and IRI during day time, while such a similarity is not recognized in night time data. DEMETER Te is 700 K higher than IRI Te for the same value of Ne. When Ne is less than 10(4) cm(-3) in night time, significant reductions in DEMETER Te are observed, which is close to expected values. Such discrepancies from the reference data and some peculiar behaviors of DEMETER Te and Ne data necessitate a careful attention in using them in consideration of their data alterations. However, their relative variations and averaged behavior in time contain useful information for scientific studies such as dependencies on solar irradiance and wave-4 longitudinal structure under certain conditions (Ne > 10(4) cm(-3) and F10.7 < 100). (C) 2013 COSPAR. Published by Elsevier Ltd. All rights reserved
Demeter: A Fast and Energy-Efficient Food Profiler Using Hyperdimensional Computing in Memory
No full textFood profiling is an essential step in any food monitoring system needed to prevent health risks and potential frauds in the food industry. Significant improvements in sequencing technologies are pushing food profiling to become the main computational bottleneck. State-of-the-art profilers are unfortunately too costly for food profiling. Our goal is to design a food profiler that solves the main limitations of existing profilers, namely (1) working on massive data structures and (2) incurring considerable data movement, for a real-time monitoring system. To this end, we propose Demeter, the first platform-independent framework for food profiling. Demeter overcomes the first limitation through the use of hyperdimensional computing (HDC) and efficiently performs the accurate few-species classification required in food profiling. We overcome the second limitation by the use of an in-memory hardware accelerator for Demeter (named Acc-Demeter) based on memristor devices. Acc-Demeter actualizes several domain-specific optimizations and exploits the inherent characteristics of memristors to improve the overall performance and energy consumption of Acc-Demeter. We compare Demeter’s accuracy with other industrial food profilers using detailed software modeling. We synthesize Acc-Demeter’s required hardware using UMC’s 65nm library by considering an accurate PCM model based on silicon-based prototypes. Our evaluations demonstrate that Acc-Demeter achieves a (1) throughput improvement of 192× and 724× and (2) memory reduction of 36× and 33× compared to Kraken2 and MetaCache (2 state-of-the-art profilers), respectively, on typical food-related databases. Demeter maintains an acceptable profiling accuracy (within 2% of existing tools) and incurs a very low area overhead.Computer EngineeringQuantum & Computer Engineerin
Singular integrals along 𝑁 directions in ℝ²
No full textWe prove optimal bounds in
L
2
(
R
2
)
L^2(\mathbb {R}^2)
for the maximal operator obtained by taking a singular integral along
N
N
arbitrary directions in the plane. We also give a new proof for the optimal
L
2
L^2
bound for the single scale Kakeya maximal function in the plane.</p
A decoupling for Cantor-like sets
No full textWe consider partitions of the parabola determined by Cantor-like sets and prove decouplings in the range 2 ≤ p ≤ 6 that are independent of the parameters defining these sets. In the process, we further clarify and simplify the argument from [2]
The best constants associated with some weak maximal inequalities in ergodic theory
No full textAbstract. We introduce a new device of measuring the degree of the failure of convergence in the ergodic theorem along subsequences of integers. Relations with other types of bad behavior in ergodic theory and applications to weighted averages are also discussed.
A decoupling for Cantor-like sets
No full textWe consider partitions of the parabola determined by Cantor-like sets and prove decouplings in the range 2 ≤ p ≤ 6 that are independent of the parameters defining these sets. In the process, we further clarify and simplify the argument from [2]
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