A survey on trust based detection and isolation of malicious nodes in ad-hoc and sensor networks

Mobile ad-hoc networks （MANETs） and wireless sensor networks （WSNs） have gained remarkable apprecia- tion and technological development over the last few years. Despite ease of deployment, tremendous applications and significant advantages, security has always been a challeng- ing issue due to the nature of environments in which nodes operate. Nodes＇ physical capture, malicious or selfish behav- ior cannot be detected by traditional security schemes. Trust and reputation based approaches have gained global recog- nition in providing additional means of security for decision making in sensor and ad-hoc networks. This paper provides an extensive literature review of trust and reputation based models both in sensor and ad-hoc networks. Based on the mechanism of trust establishment, we categorize the state- of-the-art into two groups namely node-centric trust mod- els and system-centric trust models. Based on trust evidence, initialization, computation, propagation and weight assign- ments, we evaluate the efficacy of the existing schemes. Fi- nally, we conclude our discussion with identification of some unresolved issues in pursuit of trust and reputation manage- ment.

Batch Preparation and Characterization of Electrospun Porous Polylactic Acid‑Based Nanofiber Membranes for Antibacterial Wound Dressing

A good wound dressing needs to promote wound healing and tissue repair when the skin is injured.In this study,a self-made spherical section free surface electrospinning device was used to produce large quantities of electrospun porous polylactic acid(PLA)/chitosan(CS)/aloin nanofiber membranes(NFMs)for antibacterial wound dressing.The porous structures of PLAbased nanofibers were controlled by adjusting the weight ratios of mixed solvent and solute.The results showed that highquality porous PLA/CS/aloin(PCA)NFMs were obtained when the weight ratios of chloroform/N,N-dimethylformamide and PLA:CS were 90/10 and 7:1,respectively.The porous PCA NFMs exhibited high porosity,acceptable mechanical properties,moderate hydrophobicity,good swelling property,and high water vapor transmission rate.Moreover,they also showed excellent blood coagulative,antibacterial,biocompatible properties,which had the potential to be used in the application of antibacterial wound dressings.

High-Throughput Free Surface Electrospinning Using Solution Reservoirs with Different Depths and Its Preparation Mechanism Study

For obtaining high-throughput production of nanofibers,the preparation mechanism of a self-made spherical section free surface electrospinning(SSFSE)using solution reservoirs with different depths was studied.The effects of the solution res-ervoir depth on the SSFSE process as well as the quality and yield of polyacrylonitrile(PAN)nanofibers were investigated experimentally using high-speed camera,precise electronic balance and scanning electron microscopy.Furthermore,the results were analyzed theoretically by response surface methodology(RSM)and numerical simulation.The values predicted by the established RSM model and the electric field results obtained by Maxwell 3D were all consistent with the experimental data,which showed that the different depths of the solution reservoir had little effect on the quality of PAN nanofibers,but had great effects on the yields of them.The PAN nanofibers prepared have the best quality and the highest yields when the maximum depth of the solution reservoir was 4.29 mm.