In this paper we present DESMAC a contention based Medium Access Control protocol for Diffusion based routing in Wireless Sensor Networks. One of the main challenges in WSNs is to balance delay efficiency and energy consumption. Surveillance and monitoring application as well as many other need low latency data delivery; but, since sensor nodes have a small source of energy usually Active/Sleep...

I give a summary of results from the WIRE satellite, which has been used to observe bright stars from 1999–2000 and 2003–2006. The WIRE targets are monitored for up to five weeks with a duty cycle of 30–40%. The aim has been to characterize the flux variation of stars across the Hertzsprung-Russell diagram. I present an overview of the results for solar-like stars, δ Scuti stars, giant stars, a...

Battery consumption is a key aspect in the performance of wireless sensor networks. One of the most promising technologies for this type of networks is 802.15.4/ZigBee. This paper presents an empirical characterization of battery consumption in commercial 802.15.4/ZigBee motes. This characterization is based on the measurement of the current that is drained from the power source under different...

In this Letter, a discrete-time Markov Chain model is developed to study performance of IEEE 802.15.4 under low duty cycle. The performance is measured in terms of aggregate throughput and average power consumption per packet. The proposed analytical model is verified through ns2 simulations.

In this paper we discuss the lifetime of an battery powered device which acts as a gateway between a wireless sensor network and a standard network. The wireless communication standards used are IEEE802.15.4 and IEEE802.11g. The two parameters which are of utmost importance but also contradicting each other are communication delay and lifetime of the gateway node. Our results clearly show that ...

In wireless sensor networks, the routing control overhead could be large because multiple relays are involved in the routing operation. In order to mitigate this problem, a promising solution is to use tier-based anycast protocols. The main shortcoming of these protocols is that they can consume a much greater amount of energy as compared with other competing protocols using deterministic routi...

The novel digital-to-analog conversion technique studied in this paper, is founded on the digital duty-cycle modulation principle. It consists of a simple digital duty-cycle modulation program loaded in the flash memory of a microcontroller and an external analog low pass filter. Both pulse width and modulation period, simultaneously evolve according to the variation of the modulating input. Th...

We consider the energy efficiency of medium access control (MAC) in low power wireless communication where multiple channels are available and the duty cycle of (send, receive, and idle) channel access is controllable. We show that in this setting maximization of MAC energy efficiency reduces to maximizing the aggregate channel utilization and minimizing the aggregate duty cycle channel access....

The protein releasing kinetics of Saccharomyces cerevisiae cells were investigated by using the ultrasonication method. The effects of acoustic power, duty cycle % of a sonicator, medium pH and cell concentration on protein release were examined. An attempt was also made to enhance cell disruption further by adding glass beads to the solution. An increase with protein release was observed with ...

This paper presents a new concept of continuous-valued logic (Multi level logic) (CVL) which can be applied to control the pulse width of an internally generated PWM in a microcontroller. The input threshold voltage controls duty cycle of generated PWM. The basis of continuous-valued logic (CVL) relies on the unstable generated oscillation of a digital output where the program referred non-Schm...