117 research outputs found
An analysis of a large scale habitat monitoring application
Habitat and environmental monitoring is a driving application for wireless sensor networks. We present an analysis of data from a second generation sensor networks deployed during the summer and autumn of 2003. During a 4 month deployment, these networks, consisting of 150 devices, produced unique datasets for both systems and biological analysis. This paper focuses on nodal and network performance, with an emphasis on lifetime, reliability, and the the static and dynamic aspects of single and multi-hop networks. We compare the results collected to expectations set during the design phase: we were able to accurately predict lifetime of the single-hop network, but we underestimated the impact of multihop traffic overhearing and the nuances of power source selection. While initial packet loss data was commensurate with lab experiments, over the duration of the deployment, reliability of the backend infrastructure and the transit network had a dominant impact on overall network performance. Finally, we evaluate the physical design of the sensor node based on deployment experience and a post mortem analysis. The results shed light on a number of design issues from network deployment, through selection of power sources to optimizations of routing decisions
Wireless sensor network for cattle monitoring system
This paper describes a cost effective Wireless Sensor Network (WSN) technology for monitoring the health of dairy cows. By monitoring and understanding the cow individual and herd behaviour, farmers can potentially identify the onset of illness, lameness or other undesirable health conditions. However, the WSN implementation needs to cope with various technical challenges before it can be suitably and routinely applied in cow management. This paper discusses results concerning data transportation (i.e. mobility) from the cow mounted sensory devices
Implementation of a herd management system with wireless sensor networks
This paper investigates an adaptation of Wireless Sensor Networks (WSNs) to cattle monitoring applications. The proposed solution facilitates the requirement for continuously assessing the condition of individual animals, aggregating and reporting this data to the farm manager. There are several existing approaches to achieving animal monitoring, ranging from using a store and forward mechanism to employing GSM-based techniques; these approaches only provide sporadic information and introduce a considerable cost in staffing and physical hardware. The core of this study is to overcome the aforementioned drawbacks by using alternative cheap, low power consumption sensor nodes capable of providing real-time communication at a reasonable hardware cost. In this paper, both the hardware and software has been designed to provide a solution which can obtain real-time data from dairy cattle whilst conforming to the limitations associated with WSNs implementations
Shawn: A new approach to simulating wireless sensor networks
We consider the simulation of wireless sensor networks (WSN) using a new
approach. We present Shawn, an open-source discrete-event simulator that has
considerable differences to all other existing simulators. Shawn is very
powerful in simulating large scale networks with an abstract point of view. It
is, to the best of our knowledge, the first simulator to support generic
high-level algorithms as well as distributed protocols on exactly the same
underlying networks.Comment: 10 pages, 2 figures, 2 tables, Latex, to appear in Design, Analysis,
and Simulation of Distributed Systems 200
Collision-free Time Slot Reuse in Multi-hop Wireless Sensor Networks
To ensure a long-lived network of wireless communicating sensors, we are in need of a medium access control protocol that is able to prevent energy-wasting effects like idle listening, hidden terminal problem or collision of packets. Schedule-based medium access protocols are in general robust against these effects, but require a mechanism to establish a non-conflicting schedule. In this paper, we present such a mechanism which allows wireless sensors to choose a time interval for transmission, which is not interfering or causing collisions with other transmissions. In our solution, we do not assume any hierarchical organization in the network and all operation is localized. We empirically show that our localized algorithm is successful within a factor 2 of the minimum necessary time slots in random networks; well in range of the expected (worst case) factor 3-approximation of known first-fit algorithms. Our algorithm assures similar minimum distance between simultaneous transmissions as CSMA(/CD)-based approaches
Deterministic Secure Positioning in Wireless Sensor Networks
Properly locating sensor nodes is an important building block for a large
subset of wireless sensor networks (WSN) applications. As a result, the
performance of the WSN degrades significantly when misbehaving nodes report
false location and distance information in order to fake their actual location.
In this paper we propose a general distributed deterministic protocol for
accurate identification of faking sensors in a WSN. Our scheme does \emph{not}
rely on a subset of \emph{trusted} nodes that are not allowed to misbehave and
are known to every node in the network. Thus, any subset of nodes is allowed to
try faking its position. As in previous approaches, our protocol is based on
distance evaluation techniques developed for WSN. On the positive side, we show
that when the received signal strength (RSS) technique is used, our protocol
handles at most faking sensors. Also, when the
time of flight (ToF) technique is used, our protocol manages at most misbehaving sensors. On the negative side, we prove
that no deterministic protocol can identify faking sensors if their number is
. Thus our scheme is almost optimal with respect
to the number of faking sensors. We discuss application of our technique in the
trusted sensor model. More precisely our results can be used to minimize the
number of trusted sensors that are needed to defeat faking ones
Application of UWB wireless MIMO connectivity inside ships
In this paper, Ultra wideband (UWB) technology is
proposed for replacing the large amounts of wiring used in ships which can cause serious problems like electrical interference, short circuit fires and similar trouble.There are numerous applications of Wireless Sensor Networks (WSNs) like in target tracking, monitoring a large number of sensors at vital points with actuators, controllers etc.. However there are not many studies which focus on implementing this technology in Ships. Wireless communications can be difficult in ships due to many metallic structures. The proposed UWB technology is based on novel pulse shapes which are derived from mono cycle sine waves in the GHz range, which have been practically tested and found to comply with the FCC regulations, in terms of power levels and spectral mask limitations. The technique can be operated as a high bit rate fast digital personal area network (PLAN).The results obtained practically show that this wireless solution may provide cost-effective alternative to the huge amount of wiring and cables, which are used to interconnect sensors and peripheral devices to central digital control units.The proposed scheme has
been analysed theoretically and implemented practically as well as by simulation. It gave sound results in terms of cost, speed, channel capacity as well as power and spectral mask compliance with FCC regulations
Monitoring wild animal communities with arrays of motion sensitive camera traps
Studying animal movement and distribution is of critical importance to
addressing environmental challenges including invasive species, infectious
diseases, climate and land-use change. Motion sensitive camera traps offer a
visual sensor to record the presence of a broad range of species providing
location -specific information on movement and behavior. Modern digital camera
traps that record video present new analytical opportunities, but also new data
management challenges. This paper describes our experience with a terrestrial
animal monitoring system at Barro Colorado Island, Panama. Our camera network
captured the spatio-temporal dynamics of terrestrial bird and mammal activity
at the site - data relevant to immediate science questions, and long-term
conservation issues. We believe that the experience gained and lessons learned
during our year long deployment and testing of the camera traps as well as the
developed solutions are applicable to broader sensor network applications and
are valuable for the advancement of the sensor network research. We suggest
that the continued development of these hardware, software, and analytical
tools, in concert, offer an exciting sensor-network solution to monitoring of
animal populations which could realistically scale over larger areas and time
spans
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