Frequent oscillatory criteria forpartial difference equations with several delays

AbstractThis paper is concerned with partial difference equations with several delays of theform aAm+1,n+bAm,n+1−dAm,n+∑i=1rpi(m,n)Am−σi,n−τi=0,m,n=0,1,2,…, where a, b, and d are three positive real constants, σi, τi, and τ are positive integers, and {pi(m,n)} are real double sequences, i = 1,2,,τ. Some new frequent oscillation criteria for this equation are derived

Algorithm of Abnormal Audio Recognition Based on Improved MFCC

AbstractCharacteristics extraction has a great effect on the audio training and recognition in the audio recognition system. MFCC algorithm is a typical characteristics extraction method with stable performance and high recognition rate. For the situation that MFCC has a large amount of computation, an improved algorithm MFCC_E is introduced. The computation of MFCC_E is reduced by 50% compared with the standard algorithm MFCC, and it make the hardware implementation is easy. The experimental result indicated that MFCC_E and MFCC have the same recognition rate roughly, yet the computational complexity of MFCC_E is much smaller

Remainders of semitopological groups or paratopological groups

We mainly discuss the remainders of Hausdorff compactifications of paratopological groups or semitopological groups. Thus, we show that if a nonlocally compact semitopological group G has a compactification bG such that the remainder Y = bG \ G possesses a locally countable network, then G has a countable π -character and is also first-countable, that if G is a nonlocally compact semitopological group with locally metrizable remainder, then G and bG are separable and metrizable, that if a nonlocally compact paratopological group has a remainder with sharp base, then G and bG are separable and metrizable, and that if a nonlocally compact ℝ1-factorizable paratopological group has a remainder which is a k -semistratifiable space, then G and bG are separable and metrizable. These results improve some results obtained by C. Liu (Topology Appl., 159, 1415–1420 (2012)) and A.V. Arhangel’skїǐ and M. M. Choban (Topology Proc., 37, 33–60 (2011)). Moreover, some open questions are formulated.У даній статті, в основному, розглядаються залишковi члени хаусдорфових компактифiкацiй паратопологічних груп або напівтопологічних груп. Tак, показано, що у випадку, коли нелокально компактна напівтопологічна група G має компактифікацію bG таку, що залишковий член Y=bG∖G має локально злічєнну мережу, група G має злічєнний π-характер, а також є першозліченною. Також доведено, що для нелокально компактної напівтопологічної групи з локально метризовним залишковим членом групи G i bG є сепарабельними i метризовними. Крім того, якщо нелокально компактна паратопологічна група має залишковий член з точною базою, то групи G i bG є сепарабельними і метризовними, а якщо нелокально компактна R1 -факторизовна паратопологічна група має залишковий член, який є простором, що допускає k-напівспрямлення, то групи G i bG є також сепарабельними i метризовними. Наведені результати покращують деякі результати, отримані C. Liu (Topology and Appl. - 2012. - 159. - P. 1415-1420) i A. V. Arhangel'skii, M. M. Choban (Topology Proc. - 2011. - 37. - P. 33 - 60). Крім того, сформульовано деякі відкриті питання

Quantifying immediate price impact of trades based on the kk-shell decomposition of stock trading networks

Traders in a stock market exchange stock shares and form a stock trading network. Trades at different positions of the stock trading network may contain different information. We construct stock trading networks based on the limit order book data and classify traders into $k$ classes using the $k$-shell decomposition method. We investigate the influences of trading behaviors on the price impact by comparing a closed national market (A-shares) with an international market (B-shares), individuals and institutions, partially filled and filled trades, buyer-initiated and seller-initiated trades, and trades at different positions of a trading network. Institutional traders professionally use some trading strategies to reduce the price impact and individuals at the same positions in the trading network have a higher price impact than institutions. We also find that trades in the core have higher price impacts than those in the peripheral shell.Comment: 6 pages including 3 figures and 1 tabl

SPEED AND SPIN OF 40MM TABLE TENNIS BALL AND THE EFFECTS ON ELITE PLAYERS

The 40mm table tennis ball has been officially used by ITTF since October 2000. The aim of this study was to identify the characteristics of the large (40mm) ball and the effects on the technique of elite players. In this study, Singapore elite players received both topspin and backspin balls from a robot. Three video cameras were applied to capture video data of Singapore elite players for three-dimensional motion analysis at a rate of 200 fields/second. Both speed and spin of 38mm and 40mm balls were calculated. The men and women players of different styles using different techniques including attack, loop and service, were analyzed and compared quantitatively and the effects of these differences on these elite players is discussed