A secure and energy balanced clustering protocol for underwater wireless sensor networks In Underwater Wireless Sensor Networks (UWSNs), clusterbased network architectures are widely used, which can balance energy consumption and prolong the lifetime of network. Hence, existing protocols amid at election of the optimal cluster head(CH), which are mainly based on residual energy or minimum energy consumption. Constrained by the particularities and the harsh working environment, UWSNs are vulnerable to many kinds of attacks. The malicious attacker or compromised node may be selected as CH by forging residual energy, and then capture packets and disrupt operation of networks. Trust management mechanisms can detect and remove malicious nodes by detecting and evaluating behaviors of nodes. In this article, an overview of existing trust management mechanisms and clustering protocols is given. To secure UWSNs, a trustbased secure and energy balanced clustering protocol is proposed to enhance the security of UWSNs.

A Subregional MonitoringOriented Topology Control Strategy in UWSNs Underwater wireless sensor networks (UWSNs) have become crucial for many different applications, such as marine pastures, which needs stratified aquaculture according to the habitat and range of activities of marine organisms. This type of application poses a significant challenge to network topology because strengthening the monitoring of the living conditions and collecting underwater data on organisms in different regions is necessary. In this paper, a new concept of subregional monitoring is proposed, and subregions with frequent activities of marine organisms are taken as the key monitoring areas, i.e., the areas of interest (AOIs). Then, SFRG, an energybalanced and robust topology based on scalefree network and rigid graph theory, is proposed to strengthen the monitoring of the AOIs. The topology of a rigid graph is constructed in AOI, and the entire network is scalefree network with powerlaw degree distribution, when the rigid graph is regarded as a node. Furthermore, a transmission algorithm based on the SFRG is suggested to prolong the network lifetime. The algorithm guarantees that 90% of the received packets are from the AOIs. The simulation results demonstrate that the SFRG effectively prolongs the network lifetime and improves the network robustness, which provides a strong support in strengthening the monitoring of AOIs and balancing the energy consumption.