Extreme Measures for Extreme Weather

Effective disaster prevention and response have become top priorities for local governments across China For three days,a torrential downpour pounded Wangmo,a small mountainous county in southwest China’s Guizhou Province.The June 3-5

Simulation of the extreme waves generated by typhoon Bolaven (1215) in the East China Sea and Yellow Sea

Record-breaking high waves occurred during the passage of the typhoon Bolaven（1215）（TYB） in the East China Sea（ECS） and Yellow Sea（YS） although its intensity did not reach the level of a super typhoon.Winds and directional wave measurements were made using a range of in-situ instruments mounted on an ocean tower and buoys.In order to understand how such high waves with long duration occurred,analyses have been made through measurement and numerical simulations.TYB winds were generated using the TC96 typhoon wind model with the best track data calibrated with the measurements.And then the wind fields were blended with the reanalyzed synoptic-scale wind fields for a wave model.Wave fields were simulated using WAM4.5 with adjustment of C_d for gust of winds and bottom friction for the study area.Thus the accuracy of simulations is considerably enhanced,and the computed results are also in better agreement with measured data than before.It is found that the extremely high waves evolved as a result of the superposition of distant large swells and high wind seas generated by strong winds from the front/right quadrant of the typhoon track.As the typhoon moved at a speed a little slower than the dominant wave group velocity in a consistent direction for two days,the wave growth was significantly enhanced by strong wind input in an extended fetch and non-linear interaction.

Real-time human blood pressure measurement based on laser self-mixing interferometry with extreme learning machine

In this paper, we present a method based on self-mixing interferometry combing extreme learning machine for real-time human blood pressure measurement. A signal processing method based on wavelet transform is applied to extract reversion point in the self-mixing interference signal, thus the pulse wave profile is successfully reconstructed. Considering the blood pressure values are intrinsically related to characteristic parameters of the pulse wave, 80 samples from the MIMIC-II database are used to train the extreme learning machine blood pressure model. In the experiment, 15 measured samples of pulse wave signal are used as the prediction sets. The results show that the errors of systolic and diastolic blood pressure are both within 5 mm Hg compared with that by the Coriolis method.

Accurate estimation of the largest divergence rate for a class of the 3rd-order switched linear systems

The largest divergence rate is a characterization of the stability behavior for dynamic systems, which has been proven to be equal to the least possible common matrix set measure （extreme measure） of switched linear systems. To determine the largest divergence rate is an interesting and open problem. In this paper, an algorithm is introduced to estimate the largest divergence rate for a class of the 3rd-order switched linear systems, by which any desired accurate estimation could be derived. It explores a way to determine the largest divergence rate for the 3rd-order switched linear systems. Furthermore, the accurate estimation provides a qualitative and quantitative analysis for guaranteed stability of switched linear systems.