Papers by Author: Xu Sheng Kang

Abstract: Terahertz spectra of terbutaline sulfate in the range of 0.2 to 2.2 THz was obtained by THz time-domain spectroscopy. The discrete wavelet transform was applied to de-noising terahertz waveforms. The signal was decomposed into five layers by wavelet decomposition, and then the high-frequency noise signal was eliminated by wavelet reconstruction. Another try was through calculating the standard deviation of the noise signal by the 1-th level signals which got from wavelet decomposition, and then the soft threshold and hard threshold de-noising method was employed respectively. The robustness of these wavelet de-noising methods was testified in this paper, and the absorption and refraction spectra of terbutaline sulfate were got at last. The result of experiment indicts that wavelet can enhance the signal to noise ratio of system and this paper provides a new way for the detection of terbutaline sulfate.

Abstract: The Great Pacific Garbage Patch which characterized by exceptionally high concentrations of suspended plastic, chemical sludge, and other debris, has a variety of severe influence on the marine life and human beings. Therefore, cleaning up the patch immediately is a matter of great urgency. To solve the problem, three models which are based on different differential equations to predict the amount of waste plastic poured into the ocean are established. According to the basic model, in about next 20 years, the Pacific Ocean will be unable to hold more garbage. Based on the fact that salvaging the waste plastic in the ocean contributes to controlling marine pollution, in accordance with the better model, the Pacific Ocean still has the ability to accommodate garbage before 2060. By improving the better model, a series of results are obtained. Around 2060, the area of the Pacific Ocean Garbage Patch will reach relatively steady state; meanwhile, the annual emissions of the plastic will reach 32,397,273.47 tons. To keep a relatively stable state the area which should be cleaned up will reach about 3,601,672 square kilometers per year. To compare the effect of government increasing taxation and plastic salvaging, a conclusion is reached that the huge economic losses caused by taxes are far more than the amount of money spent in salvaging the plastic garbage.

Abstract: As time goes by, hazard rate of the society would increase if crime prediction was not implemented. Based on objective factors of offenders and victims characteristics, AHP method can be established to get a quantitative and qualitative analysis on crime prediction. Crime prediction is a strategic and tactical measure for crime prevention. According to AHP analysis, two prediction models of the optimal predictive crime locations are put forward. Standard Deviational Ellipses Model and Key Feature adjusted Spatial Choice Model were formulated to account for the anticipated position with various elements from AHP method. These models could be applied in a computer simulation of situation tests of the series murders. Besides, applying those models in certain real case demonstrates how the models work. Through models comparison, the results are summarized that Key Feature adjusted Spatial Choice Model is more conducive in confirming the guilty place. In conclusion, the suggested models, including detailed criminal map, are easy to implement.