adequate coverage is one of the main problems for distributed wireless sensor networks and the effectiveness of that highly depends on the sensor deployment scheme. given a finite number of sensors, optimizing the sensor deployment will provide sufficient sensor coverage and save power of sensors for movement to target location to adequate coverage. in this paper, we apply fuzzy logic system to...

wireless sensor networks (wsns) have many applications in the areas of commercial, military and environmental requirements. regarding the deployment of low cost sensor nodes with restricted energy resources, these networks face a lot of security challenges. a basic approach for preparing a secure wireless communication in wsns, is to propose an efficient cryptographic key management protocol be...

sybil attacks pose a serious threat for wireless sensor networks (wsn) security. they can create problems in routing, voting schemes, decision making, distributed storage and sensor re-programming. in a sybil attack,the attacker masquerades as multiple sensor identities, that are actually controlled by one or a few existing attacker nodes. sybil identities are fabricated out of stolen keys, obt...

in this study, a specific ch4 sensor is fabricated based on interdigitated electrode that modified with core-shell of tungsten carbide/tin oxide (wc/sno2) nanoparticles by wet chemical method in different percents of carbon and tungsten. the morphology of wet chemical-synthesized wc/sno2 core-shell was evaluated by different methods such as patterned x-ray diffraction (xrd), and particle size a...

urease was immobilized on platinum electrode both by chemical binding and electropolymerization.the conductometric urea biosensor thus prepared showed a detection limit of 4.9×10-5 m and linear dynamic range from 4.9×10-5 to 5.8×10-3 m for urea concentration when the enzyme is covalently immobilized on pt electrodes. conductometric transducers respond to the changes in ionic strength thereby le...