5,613 research outputs found
Introducing a new technology to enhance community sustainability: An investigation of the possibilities of sun spots
The introduction of the Sun SPOT, Small Programmable Object Technology, developed by Sun Microsystems has been depicted as providing a revolutionary change in cyber physical interaction. Based on Sun Java Micro Edition (ME), this sensor technology has the potential to be used across a number of discipline areas to interface with systems, the environment and biological domains. This paper will outline the potential of Sun SPOTs to enhance community sustainability. An action based research project was carried out to investigate the potential uses of these technologies and develop a prototype system as a proof of concept. The research will compare Sun SPOTs with similar technologies, provide an assessment of the technology, and propose a number of possible implementations of the technology to enhance community sustainability
Pushing towards the Limit of Sampling Rate: Adaptive Chasing Sampling
Measurement samples are often taken in various monitoring applications. To
reduce the sensing cost, it is desirable to achieve better sensing quality
while using fewer samples. Compressive Sensing (CS) technique finds its role
when the signal to be sampled meets certain sparsity requirements. In this
paper we investigate the possibility and basic techniques that could further
reduce the number of samples involved in conventional CS theory by exploiting
learning-based non-uniform adaptive sampling.
Based on a typical signal sensing application, we illustrate and evaluate the
performance of two of our algorithms, Individual Chasing and Centroid Chasing,
for signals of different distribution features. Our proposed learning-based
adaptive sampling schemes complement existing efforts in CS fields and do not
depend on any specific signal reconstruction technique. Compared to
conventional sparse sampling methods, the simulation results demonstrate that
our algorithms allow less number of samples for accurate signal
reconstruction and achieve up to smaller signal reconstruction error
under the same noise condition.Comment: 9 pages, IEEE MASS 201
Transmission Power Measurements for Wireless Sensor Nodes and their Relationship to the Battery Level
In this work we focus on the new generation EYESIFXv2 [1] wireless sensor nodes by carrying out experimental measurements on power related quantities. In particular, our aim is to characterize the relationship between the level of the battery and the transmission power radiated by the node. The present results point out the non linear and non trivial effects due to the output potentiometer which can be used to tune the transmission power. It shall be observed that a thorough study of how battery and/or potentiometer settings translate to actual transmitted power levels is crucial to e.g. design correct power control algorithms, which can effectively operate under any operational condition of the wireless sensor device
The Mason Test: A Defense Against Sybil Attacks in Wireless Networks Without Trusted Authorities
Wireless networks are vulnerable to Sybil attacks, in which a malicious node
poses as many identities in order to gain disproportionate influence. Many
defenses based on spatial variability of wireless channels exist, but depend
either on detailed, multi-tap channel estimation - something not exposed on
commodity 802.11 devices - or valid RSSI observations from multiple trusted
sources, e.g., corporate access points - something not directly available in ad
hoc and delay-tolerant networks with potentially malicious neighbors. We extend
these techniques to be practical for wireless ad hoc networks of commodity
802.11 devices. Specifically, we propose two efficient methods for separating
the valid RSSI observations of behaving nodes from those falsified by malicious
participants. Further, we note that prior signalprint methods are easily
defeated by mobile attackers and develop an appropriate challenge-response
defense. Finally, we present the Mason test, the first implementation of these
techniques for ad hoc and delay-tolerant networks of commodity 802.11 devices.
We illustrate its performance in several real-world scenarios
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