Seabed photographing has been applied with various underwater camera apparatuses(UCAs)for observations of megabenthic epifauna,which reveals more details than traditional sampling tools do.In this study,we improved a ...Seabed photographing has been applied with various underwater camera apparatuses(UCAs)for observations of megabenthic epifauna,which reveals more details than traditional sampling tools do.In this study,we improved a UCA named a towed underwater video-camera system(TUV system)with image processing software for seabed photographing in coastal areas up to 100 m.In May 2017,the TUV system was tested at 4 stations in the Zhangzi Island marine area in the northern Yellow Sea to investigate local megabenthic epifauna,especially brittle stars.At each station,more than 500 good seabed photographs each in area of 0.1550 m2 were obtained in just 10 min.Almost all of the epifauna larger than 1 mm could be identified from the photographs,including echinoderms,bivalves,cnidarians,and crustaceans.Three dominant brittle stars(Ophiopholis mirabilis,Ophiura sarsii vadicola,and Stegophiura sladeni)were spotted,and their abundance,disc diameter,cluster size,and coverage area were calculated and analyzed from the seabed photographs.The results show that the TUV system could be applied in coastal waters of hard sandy bottoms and could be used for quantitative investigations of megabenthic epifauna.展开更多
Wireless Sensor Networks (WSNs) are a pioneering technology in many environmental monitoring applications owing to their ability to be deployed for long periods of time in locations that cannot be reached manually. On...Wireless Sensor Networks (WSNs) are a pioneering technology in many environmental monitoring applications owing to their ability to be deployed for long periods of time in locations that cannot be reached manually. One such use-case is the monitoring of underwater sediment transport, a process that plays a significant role in coastal erosion. Previous examples of WSNs deployed for this purpose have been in the form of underwater sensor networks (UWSNs), which have a number of shortcomings from both a practical and technical viewpoint. As such, this paper provides a comparative assessment of UWSNs and an alternative deployment approach of floating echo- sounding sensor networks for the purpose of monitoring underwater sediment transport.展开更多
In coastal environment,the motion of unmanned underwater vehicle(UUV)is influenced significantly by complex current.The operational performance of UUV can be greatly improved when the impact of ocean current is consid...In coastal environment,the motion of unmanned underwater vehicle(UUV)is influenced significantly by complex current.The operational performance of UUV can be greatly improved when the impact of ocean current is considered.A global path planning method of the static obstacle environmental space is addressed in the paper.Firstly,according to the typically coastal vortex,a model of ocean current is proposed and the influence to the motion of UUV is analyzed.Secondly,to satisfy the rapid requirement in path planning,a heuristic A*algorithm is used to design global planning path with multiple constraints.Besides,to meet the UUV’s smooth path requirement,Bezier curve theory is applied.Simulation experiments are performed to illustrate the feasibility of the algorithm in the steady current and vortex environment.展开更多
基金Supported by the Key Program for International S&T Cooperation Projects:Sino-Australian Center for Healthy Coasts(No.2016YFE0101500)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA23050501,XDA19060201)the Taishan Scholars Project to SUN Song。
文摘Seabed photographing has been applied with various underwater camera apparatuses(UCAs)for observations of megabenthic epifauna,which reveals more details than traditional sampling tools do.In this study,we improved a UCA named a towed underwater video-camera system(TUV system)with image processing software for seabed photographing in coastal areas up to 100 m.In May 2017,the TUV system was tested at 4 stations in the Zhangzi Island marine area in the northern Yellow Sea to investigate local megabenthic epifauna,especially brittle stars.At each station,more than 500 good seabed photographs each in area of 0.1550 m2 were obtained in just 10 min.Almost all of the epifauna larger than 1 mm could be identified from the photographs,including echinoderms,bivalves,cnidarians,and crustaceans.Three dominant brittle stars(Ophiopholis mirabilis,Ophiura sarsii vadicola,and Stegophiura sladeni)were spotted,and their abundance,disc diameter,cluster size,and coverage area were calculated and analyzed from the seabed photographs.The results show that the TUV system could be applied in coastal waters of hard sandy bottoms and could be used for quantitative investigations of megabenthic epifauna.
文摘Wireless Sensor Networks (WSNs) are a pioneering technology in many environmental monitoring applications owing to their ability to be deployed for long periods of time in locations that cannot be reached manually. One such use-case is the monitoring of underwater sediment transport, a process that plays a significant role in coastal erosion. Previous examples of WSNs deployed for this purpose have been in the form of underwater sensor networks (UWSNs), which have a number of shortcomings from both a practical and technical viewpoint. As such, this paper provides a comparative assessment of UWSNs and an alternative deployment approach of floating echo- sounding sensor networks for the purpose of monitoring underwater sediment transport.
基金supported by National Natural Science Foundation (NNSF) of China under Grant 51179038
文摘In coastal environment,the motion of unmanned underwater vehicle(UUV)is influenced significantly by complex current.The operational performance of UUV can be greatly improved when the impact of ocean current is considered.A global path planning method of the static obstacle environmental space is addressed in the paper.Firstly,according to the typically coastal vortex,a model of ocean current is proposed and the influence to the motion of UUV is analyzed.Secondly,to satisfy the rapid requirement in path planning,a heuristic A*algorithm is used to design global planning path with multiple constraints.Besides,to meet the UUV’s smooth path requirement,Bezier curve theory is applied.Simulation experiments are performed to illustrate the feasibility of the algorithm in the steady current and vortex environment.
