Key Management Techniques for Wireless Mesh Network

Key management is one of the most important tasks in wireless mesh network. This service is responsible for key generation, distribution, and key exchange in a cryptography-based system. Due to the shared nature of WMNs and absence of globally trusted central authority, key management becomes more challenging. This chapter introduces several key management methods that can address these challenges. The fundamental approach is the secret sharing scheme created by A. Shamir, which effectively distributes keys to all participants’ network. Based on Shamir’s scheme, many authors proposed other algorithms to secure the communication channel in such a way that adversary cannot steal any information about the secret. In addition, in this chapter, a new secret sharing method using real-time synchronization among transceiver devices is presented. In this method, each node generates its key depending on its physical information and the real-time clock. Therefore, public and private keys can be managed efficiently for data encryption and prevent several external attacks to WMNs. A specific protocol is proposed to secure keys while transferring between devices to prevent internal attacks

Real-time Key Management for Wireless Mesh Network

With the rapid technological development of wireless, wireless mesh network (WMN) is one of the network models which is gradually showing its superiority through several applications and projects thus it is becoming the key of technology for IoT. Due to the vulnerable environment, limited resource and open communication channel, the security design for such networks are significantly challenging. By using realtime synchronization method between transceiver devices in the WMNs, we propose an algorithm based on secret sharing method in which each node generate its key depend on its physical information and the real-time clock. Therefore, we can manage efficiently public and private keys for data encryption and prevent several external attacks to WMNs. We also propose a specific protocol to secure our keys while transferring between devices to prevent internal attacks

Analyzing surface EMG signals to determine relationship between jaw imbalance and arm strength loss

BACKGROUND: This study investigated the relationship between dental occlusion and arm strength; in particular, the imbalance in the jaw can cause loss in arm strength phenomenon. One of the goals of this study was to record the maximum forces that the subjects can resist against the pull-down force on their hands while biting a spacer of adjustable height on the right or left side of the jaw. Then EMG measurement was used to determine the EMG-Force relationship of the jaw, neck and arms muscles. This gave us useful insights on the arms strength loss due to the biomechanical effects of the imbalance in the jaw mechanism. METHODS: In this study to determine the effects of the imbalance in the jaw to the strength of the arms, we conducted experiments with a pool of 20 healthy subjects of both genders. The subjects were asked to resist a pull down force applied on the contralateral arm while biting on a firm spacer using one side of the jaw. Four different muscles – masseter muscles, deltoid muscles, bicep muscles and trapezoid muscles – were involved. Integrated EMG (iEMG) and Higuchi fractal dimension (HFD) were used to analyze the EMG signals. RESULTS: The results showed that (1) Imbalance in the jaw causes loss of arm strength contra-laterally; (2) The loss is approximately a linear function of the height of the spacers. Moreover, the iEMG showed the intensity of muscle activities decreased when the degrees of jaw imbalance increased (spacer thickness increased). In addition, the tendency of Higuchi fractal dimension decreased for all muscles. CONCLUSIONS: This finding indicates that muscle fatigue and the decrease in muscle contraction level leads to the loss of arm strength

Preparation of antibacterial polypropylene grafted acrylic acid and immobilized silver nanoparticles by γ-irradiation method

Silver nanoparticles (AgNPs) are now being widely used as antibacterial agents due to their strong bactericidal properties and low toxicity on mammalian cells. In this study, γ-rays irradiation method was used to synthesize AgNPs from silver nitrate (AgNO3) solution and to graft acrylic acid (AAc) onto porous polypropylene (PP). Porous PP grafted with AAc (PP-g-AAc) was then immobilized with AgNPs for preparing the antimicrobial materials (PP-g-AAc/AgNPs). The results demonstrated that the grafting yield of AAc onto PP increased by the increasing of irradiation dose as well as AAc concentration. The PP-g-AAc samples with grafting degrees from 1.2 to 29.8% were immobilized with AgNPs (d ~ 10 nm, 500 ppm) to obtain antimicrobial properties. The immobilized Ag contents were from 132 to 392 ppm and corresponded to the PP-g-AAc samples at grafting degrees from 1.2 to 29.8%. The in vitro antibacterial properties of PP-g-AAc/AgNPs materials on E. coli were evaluated and the results indicated that the bactericidal efficiency (η) increased by the increase of Ag contents in the tested materials. The germicidal activities against E. coli of PP-g-AAc/AgNPs containing 363 ppm Ag were found to be nearly 100% after treating in 30 min. In addition, the inhibition zone of this PP-g-AAc/AgNPs on E. coli was also found up to 28 mm in diameter. Thus, γ-rays radiation demonstrated a strong capability in grafting functional groups (AAc) onto porous PP. Furthermore, the porous PP grafted with AAc and immobilized with AgNPs might potentially be used for elimination of bacteria in water filtering

A new record of congrid eel, Bathycongrus bleekeri (Congridae) from Vietnam

Three specimens of Bathycongrus bleekeri were collected during the survey in 2015 and 2017. The newly recorded species is described herein, a small, moderately elongate species of Bathycongrus with head and body compressed; vertical fins without black mark; tail slender, attenuated, but not filiform; trunk length 1.2 times greater than head length; teeth small, conical, in about three-four rows on jaws, in a small triangular patch on vomer; 28–29 preanal vertebrae, total of 111–113 vertebrae; 26–28 preanal lateral-line pores. Additional data on the morphology and distribution of the species increases the total number of known species in the family Congridae in Vietnamese waters to twelve

g-INFO portal: a solution to monitor Influenza A on the Grid for non-grid users

International audienceIn this paper, we introduce a portal for monitoring Influenza A on a grid-based system. Influenza A keeps on being a major threat to public health worldwide; especially if one virus can mutate itself so that it acquires the capacity for human to human transmission of H1N1 as well as the high death rate of H5N1. The existing g-INFO (Grid-based Information Network for Flu Observation) project provides a complete system for monitoring flu virus on the Grid. We present here a portal that operates on top of the g-INFO system as a solution for non-grid users to utilize grid services for analyzing molecular biology data of Influenza A