Identification and classification of landslides is a preliminary and crucial work for landslide risk assessment and hazard mitigation. The exploitation of surface deformation velocity derived from satellite synthetic aperture radar interferometry (InSAR) is a consolidated and suitable procedure for the recognition of active landslides over wide areas. However, the calculated displacement velocity from InSAR is one-dimensional motion along the satellite line of sight (LOS), representing a major hurdle for landslide type and failure mechanism classification. In this paper, different velocity datasets derived from both ascending and descending Sentinel-1 data are employed to analyze the surface ground movement of the Huangshui region (Northwestern China). With global warming, precipitation in the Huangshui region, geologically belonging to the loess basin in the eastern edge of Qing-Tibet Plateau, has been increasing, often triggering a large number of landslides, posing a potential threat to local citizens and natural and anthropic environments. After processing both SAR data geometries, the surface motion was decomposed to obtain the two-dimensional displacements (vertical and horizontal E–W). Thus, a classification criterion of the loess landslide types and failure mode is proposed, according to the analysis of deformation direction, velocities, texture, and topographic characteristics. With the support of high-resolution images acquired by remote sensing and unmanned aerial vehicle (UAV), 14 translational slides, seven rotational slides, and 10 loess flows were recognized in the study area. The derived results may provide solid support for stakeholders to comprehend the hazard of unstable slopes and to undertake specific precautions for moderate and slow slope movements.

As a key component of a Wireless Power Transmission System, a cyclotron-wave rectifier, a high power microwave to DC converter, has received more attention from scholars. This paper comprehensively analyzes various limiting factors of the output voltage and current. The results show that high frequency breakdown, the external magnetic field, and engineering realization limit the output voltage, and the space charge force limits the beam current. On this basis, by using the equivalent circuit and particle simulation, we design a cyclotron-wave rectifier with high power. The simulation results demonstrate that working at 2.45 GHz, the rectifier can obtain an output voltage of 113 kV and an output power of 791 kW. These conclusions can provide guidance for designing and application of this device.

<!-- *** Custom HTML *** --> Mapping the refined land-cover classification mapping (RLCM) is a primary and essential strategy for evaluating the ecological change and understanding the ecosystem services. A common problem during the generation of RLCM is a scale mismatch between remote sensing (RS) data and field quadrat, which leads to inaccuracy of the classification result. A multi-scale transformation method was developed via integrating RS, unmanned aerial vehicle (UAV), and field surveys in Sanjiangyuan National Park (SNP). With the help of UAV, a large number of virtual biomass quadrats were resampled and interpolated, and the quantitative thresholds of different vegetation coverage in alpine meadow and steppe were determined to improve land-cover classification accuracy. Based on the spatial-temporal analysis of RLCM from 1990 to 2017, the whole ecological coverage was becoming better, and its driving factor was attributed to government policy and climate change. This study can provide a practical suggestion for the management and sustainable development in SNP.

In a mobile social network, the movement feature of the mobile users has social aggregation characteristics, and the same mobile user who visits different communities' forms the connected network based on community. This paper studies the energy consumption optimization problem of message de-livery based on social characteristics of mobile users. The pa-per proposes an optimal energy efficiency routing strategy based on community, which minimizes the network energy consumption with a given delay. Firstly, the expected energy consumption and delay of message delivery in the connected network are obtained through Markov chain. Then a compre-hensive cost function for message deliver from a source node to a destination node is designed, which is combined with energy consumption and delay. Thus we obtain the optimization func-tion for delivering message of relay to comprehensive cost. Further, the reward function of relay is given. Finally, the op-timal expected reward of optimal relay is achieved using the optimal stopping theory, so as to realize the optimal energy efficiency routing strategy. In simulations, the average energy consumption, the average delay and the average delivery ratio of routing optimization strategy in this paper are compared with those of other routing strategies in related literatures. The results show that the strategy proposed by this paper has smaller average energy consumption, smaller average delay and bigger average delivery ratio, and better energy consump-tion optimization results can be achieved.