Energy-Efficient Data Collection over Underwater MI-Assisted Acoustic Cooperative MIMO WSNs

Underwater magnetic induction(MI)-assisted acoustic cooperative multiple-input-multipleoutput(MIMO) has been recently proposed as a promising technique for underwater wireless sensor networks(UWSNs).For the more,the energy utilization of energy-constrained sensor nodes is one of the key issues in UWSNs,and it relates to the network lifetime.In this paper,we present an energy-efficient data collection for underwater MI-assisted acoustic cooperative MIMO wireless sensor networks(WSNs),including the formation of cooperative MIMO and relay link establishment.Firstly,the cooperative MIMO is formed by considering its expected transmission range and the energy balance of nodes with it.Particularly,from the perspective of the node’s energy consumption,the expected cooperative MIMO size and the selection of master node(MN) are proposed.Sequentially,to improve the coverage of the networks and prolong the network lifetime,relay links are established by relay selection algorithm that using matching theory.Finally,the simulation results show that the proposed data collection improves its efficiency,reduces the energy consumption of the master node,improves the networks’ coverage,and extends the network lifetime.

Ecological vulnerability analysis of Beidagang National Park,China

Ecological vulnerability analysis (EVA) is vital for ecological protection,restoration,and management of wetland-type national parks.In this study,we assessed the ecological vulnerability of Beidagang National Park based upon remote sensing (RS) and geographic information system (GIS) technologies.To quantify the ecological vulnerability,10 indices were collected by the 'exposuresensitivity- adaptive capacity' model and spatial principal component analysis (SPCA) was then applied to calculate the ecological vulnerability degree (EVD).Based on the numerical values,EVD of the study area was classified into five levels: moderate,light,medium,strong,and extreme.Results showed that the average EVD value was approximately 0.39,indicating overall good ecological vulnerability in Beidagang National Park.To be specific,80.42% of the whole area was assigned to a moderate level of EVD with the highest being the tourism developed areas and the lowest being the reservoirs and offshore areas.Ecological vulnerability of the region was determined to be affected by the natural environment and anthropogenic disturbance jointly.The primary factors included tourism disturbance,traffic interference,exotic species invasion,land use/land cover,and soil salinization.We expected to provide some insights of the sustainable development of Beidagang National Park and would like to extend the results to other wetland-type national parks in the future.