Panzhihua Airport Landslide (Oct. 3rd 2009) and an Emergency Monitoring and Warning System Based on the Internet of Things

Panzhihua city （26°O5＇-27°21＇N, 101°OS＇- 102°15＇E）, located in a mountainous area, is one of the large cities in Sichuan province, China. A landslide occurred in the filling body of the eastern part of the Panzhihua airport on October 3, 2009 （hereafter called the lo.3 landslide）. We conducted field survey on the landslide and adopted emergency monitoring and warning models based on the Internet of Things （loT） to estimate the losses from the disaster and to prevent a secondary disaster from occurring. The results showed that four major features of the airport site had contributed to the landslide, i.e, high altitude, huge amount of filling rocks, deep backfilling and great difficulty of backfilling. The deformation process of the landslide had six stages and the unstable geological structure of high fillings and an earthquake were the main causes of the landslide. We adopted relative displacement sensing technology and Global System for Mobile Communications （GSM） technology to achieve remote, real-time and unattended monitoring of ground cracks in the landslide. The monitoring system, including five extensometers with measuring ranges of 200, 450 and 7oo mm, was continuously working for 17 months and released 7 warning signals with an average warning time of about 26 hours. At 10 am on 6 December 2009, the system issued a warning and on-site workers were evacuated and equipment protected immediately. At 2：20 medium-scale collapse monitoring site, which proved the reliability pm on 7 December, a occurred at the No. 5 justified the alarm and and efficiency of the monitoring system.

Interference-Limited Device-to-Device Multi-User Cooperation Scheme for Optimization of Edge Networking

Device-to-device （D2D） communication is an emerging technology for improving cellular networks, which plays an important role in realizing Internet of Things （IoT）. The spectrum efficiency, energy efficiency and throughput of network can be enhanced by the cooperation among multiple D2D users in a self-organized method. In order to limit the interference of D2D users and load off the energy consumption of D2D users without decreasing communication quality, an interference- limited multi-user cooperation scheme is proposed for multiple D2D users to solve the energy problem and the interference problem in this paper. Multiple D2D users use non-orthogonal spectrums to form clusters by self-organized method. Multiple D2D users are divided into different cooperative units. There is no interference among different cooperative units so as to limit the interference of each D2D user in cooperative units. When the link capacity cannot meet the requirements of the user rate, it will produce an interrupt event. In order to evaluate the communication quality, the outrage probability of D2D link is derived by considering link delay threshold, data rate and interference. Besides the energy availability and signal-to-noise ratio （SNR） of each D2D user, the distance between D2D users is considered when selecting the relaying D2D users so as to enhance the signal-to-interference-plus-noise ratio （SINR） of D2D receiving users. Combining the derived outrage probability, the relationships among the average link delay threshold, the efficiency of energy and the efficiency of capacity are studied. The simulation results show that the interference-limited multiple D2D users cooperation scheme can not only help to offioad energy consumption and limit the interference of D2D users, but also enhance the efficiency of energy and the efficiency of capacity.