473 research outputs found
SHOT PUT TECHNIQUE ANALYSIS USING ANN AMT MODEL
The purpose of this study was to analyze the technique of female shot put athletes. In this paper the ANN Analysis Model of sport Technique (ANNAMT) was applied to the data. It was shown that there were three possible ways to use this technique. The first was to reveal the general principles underlying an activity. The second method was to determine what differences exist between elite and other athletes and finally to achieve an individual technique diagnosis for direction in training. This study demonstrates the potential of the system that was developed previously for this purpose. It has the ability to standardize and program the technique analysis course, to some extent overcoming subjective decisions. This study suggests that ANNAMT could be used to establish sports training programs if the database was made available, compiled from performances of elite athletes
On precision holography for the circular Wilson loop in
The string theory calculation of the 1/2-BPS circular Wilson loop of N=4 SYM
in the planar limit at next to leading order at strong coupling is revisited in
the ratio of its semiclassical string partition function and the one dual to a
latitude Wilson loop with trivial expectation value. After applying a conformal
transformation from the disk to the cylinder, this problem can be approached by
means of the Gel'fand-Yaglom formalism. Using results from the literature and
the exclusion of zero modes from a modified Gel'fand-Yaglom formula, we obtain
matching with the known field theory result. As seen in the phaseshift method
computation, non-zero mode contributions cancel and the end result comes from
the zero mode degeneracies of the latitude Wilson loop.Comment: 7 pages, published versio
DISCUSSION ON THE CHARACTERISTICS OF UU-XIANG'S HURDLING TECHNIQUES
By using the, methods of experiment and documentary, the data and motor photo of liu Xiang attending Olympic and pre-Olympic games were collected and digitized. Based on the sport training practice, Liu-Xiang 110m hurdle sport techniques were investigated. Results show that the performance showing the technique characteristics of short flight time, long offending hurdle distance, short landing distance, high sprint pace frequency and the hip-hurdling style which postponed hold-down-hurdle time, enhanced hold-downhurdle
speed and decreased landing time. His knee conceding angle was small and pelvis swung rapidly
Flat-band and multi-dimensional fermions in Pb10(PO4)6O4
Employing a combination of first-principles calculations and low-energy
effective models, we present a comprehensive investigation on the electronic
structure of Pb(PO)O, which exhibits remarkable
quasi-one-dimensional flat-band around the Fermi level that contains novel
multi-dimensional fermions. These flat bands predominantly originate from
orbital of the oxygen molecules chain at Wyckoff positions, and
thus can be well-captured by a four-band tight-binding model. Furthermore, the
abundant crystal symmetry inherent to Pb(PO)O provides
an ideal platform for the emergence of various multi-dimensional fermions,
including a 0D four-fold degenerated Dirac fermion with quadratic dispersion, a
1D quadratic/linear nodal-line (QNL/LNL) fermion along symmetric -paths, 1D
hourglass nodal-line (HNL) fermion linked to the Dirac fermion, and a 2D
symmetry-enforced nodal surface (NS) found on the = plane. Moreover,
when considering the weak ferromagnetic order, Pb(PO)O
transforms into a rare semi-half-metal, which is characterized by the presence
of Dirac fermion and HNL fermion at the Fermi level for a single spin channel
exhibiting 100 spin polarization. Our findings reveal the coexistence of
flat bands, diverse topological semimetal states and ferromagnetism within in
Pb(PO)O, which may provide valuable insights for
further exploring intriguing interplay between superconductivity and exotic
electronic states.Comment: 8 pages, 4 figure
TI-DNS: A Trusted and Incentive DNS Resolution Architecture based on Blockchain
Domain Name System (DNS) is a critical component of the Internet
infrastructure, responsible for translating domain names into IP addresses.
However, DNS is vulnerable to some malicious attacks, including DNS cache
poisoning, which redirects users to malicious websites displaying offensive or
illegal content. Existing countermeasures often suffer from at least one of the
following weakness: weak attack resistance, high overhead, or complex
implementation. To address these challenges, this paper presents TI-DNS, a
blockchain-based DNS resolution architecture designed to detect and correct the
forged DNS records caused by the cache poisoning attacks in the DNS resolution
process. TI-DNS leverages a multi-resolver Query Vote mechanism to ensure the
credibility of verified records on the blockchain ledger and a stake-based
incentive mechanism to promote well-behaved participation. Importantly, TI-DNS
is easy to be adopted as it only requires modifications to the resolver side of
current DNS infrastructure. Finally, we develop a prototype and evaluate it
against alternative solutions. The result demonstrates that TI-DNS effectively
and efficiently solves DNS cache poisoning
SGD with a Constant Large Learning Rate Can Converge to Local Maxima
Previous works on stochastic gradient descent (SGD) often focus on its
success. In this work, we construct worst-case optimization problems
illustrating that, when not in the regimes that the previous works often
assume, SGD can exhibit many strange and potentially undesirable behaviors.
Specifically, we construct landscapes and data distributions such that (1) SGD
converges to local maxima, (2) SGD escapes saddle points arbitrarily slowly,
(3) SGD prefers sharp minima over flat ones, and (4) AMSGrad converges to local
maxima. We also realize results in a minimal neural network-like example. Our
results highlight the importance of simultaneously analyzing the minibatch
sampling, discrete-time updates rules, and realistic landscapes to understand
the role of SGD in deep learning.Comment: ICLR 2022 Spotligh
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