沙粒粒径分布对高尔夫球在沙坑中球位的影响

【目的】探索沙坑沙粒粒径特征对沙坑中高尔夫球位的影响。【方法】选取兰州市高尔夫球场常用的3种沙坑沙进行粒径分布分析,确定粒径大小、级配指数、不均匀系数、曲率系数、静止角和沙面硬度;采用模拟高尔夫球坠入沙坑的方法,以不同沙与粒径组分组合为处理,研究沙坑中球坑的大小和深度,推导不同沙粒组成对高尔夫球球位的影响以及可获得较为理想球位的沙坑沙应具备的粒径特征。【结果】选取的3种沙坑沙中,河沙质地较粗、粒径分布连续广泛且均匀、级配好、硬度大、稳定性强。从1 m高度模拟坠球,河沙球坑内径和深度显著小于土沙和山沙(P<0.05),不易产生“荷包蛋”球位。另外,通过对中粗粒径(0.25~20)mm组分和不同单一粒径组分进行1 m高度模拟坠球发现,0.25~2 mm粒径的河沙不容易产生埋嵌的“荷包蛋”球位。【结论】质地较粗、粒径分布广且均匀、级配好、细小沙粒少且粒径最佳在0.25~2 mm范围的沙能更好地形成较为理想的球位;粒径分布窄、级配差、中位粒径<0.5 mm的沙极容易形成“荷包蛋”球位。

A novel approach for detection of deception using Smoothed Pseudo Wigner-Ville Distribution (SPWVD)

For many years, the uncertainty of lie-detection systems has been one of the concerns of defense related agencies. Clearly the results of these systems must be generalized by a high value of accuracy to be acceptable by judicial systems. In this paper, a new method based on P300-based component has been proposed for lie-detection. In this regard, the test protocol is designed based on Odd-ball paradigm concealed information recognition. This test was done on 32 people and their brain signals were acquired. After preprocessing, the classic features are extracted from each single trial. After that, time-frequency (TF) transformation is applied on the sweeps and TF features are produced thereupon. Then, the best combinational feature vector is selected in order to improve classifier accuracy. Finally, Guilty and Innocent persons are classified by KNN and MLP. We found that combination of Time-Frequency and Classic features have better ability to achieve higher amount of accuracy. The obtained results show that the proposed method can detect deception by the accuracy of 89.73% which is better than other previously reported methods.