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 AdS5×S5AdS_{5}\times S^{5}

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$_{10}$(PO$_{4}$)$_{6}$O$_{4}$, which exhibits remarkable quasi-one-dimensional flat-band around the Fermi level that contains novel multi-dimensional fermions. These flat bands predominantly originate from $p_x/p_y$ orbital of the oxygen molecules chain at $4e$ Wyckoff positions, and thus can be well-captured by a four-band tight-binding model. Furthermore, the abundant crystal symmetry inherent to Pb$_{10}$(PO$_{4}$)$_{6}$O$_{4}$ 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 $k$-paths, 1D hourglass nodal-line (HNL) fermion linked to the Dirac fermion, and a 2D symmetry-enforced nodal surface (NS) found on the $k_z$=$\pi$ plane. Moreover, when considering the weak ferromagnetic order, Pb$_{10}$(PO$_{4}$)$_{6}$O$_{4}$ 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$_{10}$(PO$_{4}$)$_{6}$O$_{4}$, which may provide valuable insights for further exploring intriguing interplay between superconductivity and exotic electronic states.Comment: 8 pages, 4 figure

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

A Differentially Driven Dual-Polarized Dual-Wideband Complementary Antenna for 2G/3G/LTE Applications

A novel differentially driven dual-polarized dual-wideband complementary patch antenna with high isolation is proposed for 2G/3G/LTE applications. In order to generate dual-polarization and dual-wideband properties, a pair of biorthogonal dual-layer η-shaped tapered line feeding structures is utilized to feed two pairs of dual-layer U-shaped patches, respectively. The upper-layer U-shaped patches mainly serve the upper frequency band, while the lower-layer ones chiefly work for the lower frequency band. Besides, a horned reflector is introduced to improve radiation patterns and provide stable gain. The prototype antenna can achieve a bandwidth of 25.7% (0.78 GHz–1.01 GHz) with a stable gain of 7.8±0.7 dBi for the lower band, and a bandwidth of 45.7% (1.69 GHz–2.69 GHz) with a gain of 9.5±1.1 dBi for the upper band. Input isolation exceeding 30 dB has been obtained in the wide bandwidth. Thus, it can be potentially used as a base station antenna for 2G/3G/LTE networks