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Due to cost reduction and device miniaturization, amateur drones are now widely used in numerous civilian and commercial applications. However, the abuse of amateur drones has resulted in emerging threats to personal privacy and public security. To alleviate these threats, we design an acoustic-based surveillance system, which can achieve the capacity of amateur drones detection and localization with 24/7 (24 hours per day and 7 days per week under normal circumstances) availability. In the designed system, a detection fusion algorithm and a TDOA estimation algorithm based on the Bayesian filter are applied to improve the performance of drone detection and localization. Field experiments are carried out, and the results demonstrate that the designed system can detect and locate an amateur drone in real time with high accuracy and 24/7 availability.

Introducing the times of papers being cited to reflect the quality and international influence of scientific research, and the reputation to reflect the quality of teaching activity, this paper uses Malmquist Index based on DEA to measure efficiency, technology and productivity change of 72 Higher Educational Institutions (HEIs) directly under Ministry of Education of China in 2007-2012. Results reveal that the Total Factor Productivity (TFP) of HEIs manifests a reasonable growing tendency; the increase on technical efficiency is the mainly driving force of the increase on TFP, while the technological degression has an inhibiting effect; there are significant differences between different HEIs, regions and types. In the end, some suggestions are provided to promote continuous, stable and balance development of HEIs in China.