Effects of plastic contamination on water evaporation and desiccation cracking in soil

The characterization and quantitative analysis of nanopores in unconventional gas reservoirs utilizing FESEM–FIB and image processing: An example from the lower Silurian Longmaxi Shale, upper Yangtze region, China

Automated detection of sewer pipe defects in closed-circuit television images using deep learning techniques

Automatic quantification of crack patterns by image processing

Distributed optical fibre sensing, employing either Rayleigh, Raman, or Brillouin scattering, is the only physical-contact sensor technology capable of accurately estimating physical fields with spatial continuity along the fibre. This unique feature and the other features of standard optical fibre sensors (e.g., minimal invasiveness and lightweight, remote powering/interrogating capabilities) have for many years promoted the technology to be a promising candidate for geo-hydrological monitoring. Relentless research efforts are being undertaken to bring the technology to complete maturity through laboratory, physical models, and in-situ tests. The application of distributed optical fibre sensors to geo-hydrological monitoring is here reviewed and discussed, along with basic principles and main acquisition techniques. Among the many existing geo-hydrological processes, the emphasis is placed on those related to soil levees, slopes/landslide, and ground subsidence that constitute a significant percentage of current geohazards.

A Review of Distributed Fibre Optic Sensors for Geo-Hydrological Applications

Experimental characterization of shrinkage and desiccation cracking in thin clay layer

Ground fissure is a serious geological disaster that may endanger the safety of surrounding people and infrastructures. In this paper, the distributed fiber-optic sensing (DFOS) technology is adopted to monitor ground fissures in complicated field environments. A new fixed-point fiber-optic sensing cable (FFOSC) is designed and the corresponding installation method is developed. The results of a laboratory test and a field trial show that the FFOSC has high accuracy and is sensitive to the growth of ground fissures. The results also reveal that the FFOSC is suitable for monitoring not only the cracking widths but also the developing trends of the ground fissures. The FFOSC provides a solid basis for the investigation of ground fissure mechanism and for the mitigation of related geo-hazards.

Development and application of a fixed-point fiber-optic sensing cable for ground fissure monitoring

The formation control technology of the unmanned aerial vehicle (UAV) swarm is a current research hotspot, and formation switching and formation obstacle avoidance are vital technologies. Aiming at the problem of formation control of fixed-wing UAVs in distributed ad hoc networks, this paper proposed a route-based formation switching and obstacle avoidance method. First, the consistency theory was used to design the UAV swarm formation control protocol. According to the agreement, the self-organized UAV swarm could obtain the formation waypoint according to the current position information, and then follow the corresponding rules to design the waypoint to fly around and arrive at the formation waypoint at the same time to achieve formation switching. Secondly, the formation of the obstacle avoidance channel was obtained by combining the geometric method and an intelligent path search algorithm. Then, the UAV swarm was divided into multiple smaller formations to achieve the formation obstacle avoidance. Finally, the abnormal conditions during the flight were handled. The simulation results showed that the formation control technology based on distributed ad hoc network was reliable and straightforward, easy to implement, robust in versatility, and helpful to deal with the communication anomalies and flight anomalies with variable topology.

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Wen-Bin Suo

Papers

Experimental characterization of shrinkage and desiccation cracking in thin clay layer

Automatic quantification of crack patterns by image processing

Development and application of a fixed-point fiber-optic sensing cable for ground fissure monitoring

Formation Control Technology of Fixed-Wing UAV Swarm Based on Distributed Ad Hoc Network