Wireless sensor networks are hot. In any application in which wires used to cause problems, autonomous and wireless sensors can be positioned. An example of a project Van Hoesel is involved with, is monitoring the water quality in the fragile ecology of the Great Barrier Reef without the need of an ‘intrusive’ infrastructure. But also for climate control in buildings and for monitoring industrial processes, wireless sensor networks have been introduced. The sensors exchange information and form ‘multi hop’ connections. Because they sometimes stay in place for years, the use of battery power must be kept to a minimum.
The sensors don’t just constantly transmit their data to a central server; that would cost far too much energy. Communication is expensive in terms of energy consumption, therefore intelligence is added locally to each sensor node: the sensors know when to transmit their data and when to pass data through, coming from neighbouring sensors. For this, they have to be ‘on speaking terms’, as Van Hoesel calls it. In this way, the network itself can carry out complex tasks.
He therefore designed a so-called Medium Access (MAC) protocol, based on self organization of the network. The sensors keep an eye on their neighbours and autonomously decide whether to start transmitting or not. This also holds for the neighbours next-door to the closest neighbours: in this way, Van Hoesel avoids conflicts in the network and keeps energy use to a minimum.
This approach can be further improved by introducing passive sensors in the network: they provide data but they don’t actively participate in the multi hop communication. Passive sensors use less energy and thus extend the lifetime of the network as a whole. As wireless networks in general can be vulnerable to attacks from the outside, Van Hoesel presents adequate countermeasures.
Lodewijk van Hoesel, who defended his PhD thesis ‘Sensors on speaking terms’ on June 21 is also the cofounder –together with Paul Havinga and Stefan Dulman- of Ambient Systems, a company specialized in wireless sensor networks. The young company recently was awarded the Dutch ICTRegie Award and the Van den Kroonenberg Award, an award of the University of Twente for young entrepreneurs. Ambient Systems started cooperation with the Australian Institute of Marine Science for monitoring the water quality around the Great Barrier Reef using wireless sensor networks.
Wiebe van der Veen | alfa
A big nano boost for solar cells
18.01.2017 | Kyoto University and Osaka Gas effort doubles current efficiencies
Multiregional brain on a chip
16.01.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
18.01.2017 | Power and Electrical Engineering
18.01.2017 | Materials Sciences
18.01.2017 | Life Sciences