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| 2. |
- António, Gonga, et al.
(författare)
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Multi-channel communication vs. adaptive routing for reliable communication in WSNs
- 2012
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Ingår i: IPSN'12 - ACM/IEEE Proceedings of the 11th International Conference on Information Processing in Sensor Networks, (Beijing;16 - 20 April 2012). - New York, NY, USA : ACM. - 9781450312271 ; , s. 125-126
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Konferensbidrag (refereegranskat)abstract
- Interference and link dynamics constitute great concerns for stability and performance of protocols in WSNs. In this paper we evaluate the impact of channel hopping and adaptive routing on delay and reliability focusing on delay critical applications.
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| 3. |
- Berger, Christian, 1980, et al.
(författare)
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Model-based, Composable Simulation for the Development of Autonomous Miniature Vehicles
- 2013
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Ingår i: Mod4Sim'13: 3rd International Workshop on Model-driven Approaches for Simulation Engineering at SCS/IEEE Symposium on Theory of Modeling and Simulation in conjunction with SpringSim 2013. - 0735-9276. - 9781627480321 ; , s. 118-125
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Konferensbidrag (refereegranskat)abstract
- Modern vehicles contain nearly 100 embedded control units to realize various comfort and safety functions. These vehicle functions consist of a sensor, a data processing, and an actor layer to react intelligently to stimuli from their context. Recently, these sensors do not only perceive data from the own vehicle but more often also data from the vehicle's surroundings to understand the current traffic situation. Thus, traditional development and testing processes need to be rethought to ensure the required quality especially for safety-critical systems like a collision prevention system. On the example of 1:10 scale model cars, we outline our model-based and composable simulation approach that enabled the virtualized development of autonomous driving capabilities for model cars to compete in an international competition.
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| 4. |
- Duquennoy, Simon, et al.
(författare)
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Let the Tree Bloom: Scalable Opportunistic Routing with ORPL
- 2013
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Ingår i: SenSys '13: Proceedings of the 11th ACM Conference on Embedded Networked Sensor Systems. - New York, NY, USA : ACM. - 9781450320276
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Konferensbidrag (refereegranskat)abstract
- Routing in battery-operated wireless networks is challenging, posing a tradeoff between energy and latency. Previous work has shown that opportunistic routing can achieve low-latency data collection in duty-cycled networks. However, applications are now considered where nodes are not only periodic data sources, but rather addressable end points generating traffic with arbitrary patterns.We present ORPL, an opportunistic routing protocol that supports any-to-any, on-demand traffic. ORPL builds upon RPL, the standard protocol for low-power IPv6 networks. By combining RPL's tree-like topology with opportunistic routing, ORPL forwards data to any destination based on the mere knowledge of the nodes' sub-tree. We use bitmaps and Bloom filters to represent and propagate this information in a space-efficient way, making ORPL scale to large networks of addressable nodes. Our results in a 135-node testbed show that ORPL outperforms a number of state-of-the-art solutions including RPL and CTP, conciliating a sub-second latency and a sub-percent duty cycle. ORPL also increases robustness and scalability, addressing the whole network reliably through a 64-byte Bloom filter, where RPL needs kilobytes of routing tables for the same task.
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| 5. |
- Duquennoy, Simon, et al.
(författare)
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Poster Abstract: Opportunistic RPL
- 2013
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Ingår i: EWSN'13: Proceedings of the 10th European Conference on Wireless Sensor Networks.
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Konferensbidrag (refereegranskat)abstract
- Sensor nodes constituting Wireless Sensor Networks (WSN) are often battery-operated and have limited resources. To save energy, nodes sleep most of the time, and wake up periodically to handle communication. Such radio duty cycling poses a basic trade-off between energy and latency. In previous work, we have shown that opportunistic routing is an efficient way to achieve low-latency yet energy efficient data collection in WSN. In this paper, we extend this approach to the context of low-power IP networks, where nodes need to be addressed individually and where traffic patterns are irregular. We present ORPL, an opportunistic extension of RPL, the standard, state-of-the-art routing protocol for low-power IP networks. We discuss our preliminary results obtained with Contiki in a 137-node testbed.
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| 6. |
- Fu, Zhang, 1982, et al.
(författare)
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Managing your Trees: Insights from a Metropolitan-Scale Low-Power Wireless Network
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Low-power wireless, such as IEEE 802.15.4, is envisioned as one key technology for wireless control and communication.In the context of the Advanced Metering Infrastructure (AMI), it serves as an energy-efficient communication technology for both communications at building-scale networks and city-scale networks. Understanding real-world challenges and key properties of 802.15.4 based networks is an essential requirement for both the research community and practitioners:When deploying and operating low-power wireless networks at metropolitan-scale, a deep knowledge is essential to ensure network availability and performance at production-level quality.Similarly, researchers require realistic network models when developing new algorithms and protocols.In this paper, we present new and real-world insights from a deployed metropolitan-scale low-power wireless network:It includes 300,000 individual wireless sensors and cover a city with roughly 600,000 inhabitants.Our findings, for example, help to estimate real-world parameters such as the typical size of routing trees, their balance, and their dynamics over time.Moreover, these insights facilitate the understanding and the realistic calibration of simulation models in key properties such as reliability and throughput.
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| 7. |
- Fu, Zhang, 1982, et al.
(författare)
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Managing your Trees: Insights from a Metropolitan-Scale Low-Power Wireless Network
- 2014
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Ingår i: CCSES'14: Proceedings of the 3rd Workshop on Communications and Control for Smart Energy Systems held in conjunction with the 33rd IEEE International Conference on Computer Communications (INFOCOM).
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Konferensbidrag (refereegranskat)abstract
- Low-power wireless, such as IEEE 802.15.4, is envisioned as one key technology for wireless control and communication. In the context of the Advanced Metering Infrastructure (AMI), it serves as an energy-efficient communication technology for both communications at building-scale networks and city-scale networks. Understanding real-world challenges and key properties of 802.15.4 based networks is an essential requirement for both the research community and practitioners: When deploying and operating low-power wireless networks at metropolitan-scale, a deep knowledge is essential to ensure network availability and performance at production-level quality. Similarly, researchers require realistic network models when developing new algorithms and protocols.In this paper, we present new and real-world insights from a deployed metropolitan-scale low-power wireless network: It includes 300,000 individual wireless connected meters and covers a city with roughly 600,000 inhabitants. Our findings, for example, help to estimate real-world parameters such as the typical size of routing trees, their balance, and their dynamics over time. Moreover, these insights facilitate the understanding and the realistic calibration of simulation models in key properties such as reliability and throughput.
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| 8. |
- Fu, Zhang, 1982, et al.
(författare)
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Online Temporal-Spatial Analysis for Detection of Critical Events in Cyber-Physical Systems
- 2014
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Ingår i: 2014 IEEE International Conference on Big Data (IEEE BigData 2014). ; , s. 129-134
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Konferensbidrag (refereegranskat)abstract
- Cyber-Physical Systems (CPS) employ sensors to observe physical environments and to detect events of interest. Equipped with sensing, computing, and communication capabilities, Cyber-Physical Systems aim to make physical-systems smart(er). For example, smart electricity meters nowadays measure and report power consumption as well as critical events such as power outages. However, each day, such sensors report a variety of warnings and errors: many merely indicate transient faults or short instabilities of the physical system (environment). Thus, given the big volumes of data, the time-efficient processing of these events, especially in large-scale scenarios with hundreds of thousands of sensors, is a key challenge in CPSs. Motivated by the fact that critical events of CPSs often have temporal-spatial properties, we focus on identifying critical events by an online temporal-spatial analysis on the data stream of messages. We explicitly model the online detection problem as a single-linkage clustering on a data stream over a sliding-window, where the inherent computational complexity of the detection problem is derived. Based on this model, we propose a grid-based single-linkage clustering algorithm over a sliding-window, which is an online time-space efficient method satisfying the quick processing demand of big data streams. We analyze the performance of the proposed approach by both a series of propositions and a large, real-world data-set of deployed CPS, composing 300,000 sensors, over one year. We show that the proposed method identifies above 95% of the critical events in the data-set and save the time-space requirement by 4 orders of magnitude compared with the conventional clustering method.
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| 9. |
- Ghadimi, Euhanna, et al.
(författare)
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A metric for opportunistic routing in duty cycled wireless sensor networks
- 2012
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Ingår i: Sensor, Mesh and Ad Hoc Communications and Networks (SECON), 2012 9th Annual IEEE Communications Society Conference on. - : IEEE. - 2155-5486 .- 2155-5494. - 9781467319058 ; , s. 335-343
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Konferensbidrag (refereegranskat)abstract
- Opportunistic routing is widely known to have substantially better performance than traditional unicast routing in wireless networks with lossy links. However, wireless sensor networks are heavily duty-cycled, i.e. they frequently enter deep sleep states to ensure long network life-time. This renders existing opportunistic routing schemes impractical, as they assume that nodes are always awake and can overhear other transmissions. In this paper, we introduce a novel opportunistic routing metric that takes duty cycling into account. By analytical performance modeling and simulations, we show that our routing scheme results in significantly reduced delay and improved energy efficiency compared to traditional unicast routing. The method is based on a new metric, EDC, that reflects the expected number of duty cycled wakeups that are required to successfully deliver a packet from source to destination. We devise distributed algorithms that find the EDC-optimal forwarding, i.e. the optimal subset of neighbors that each node should permit to forward its packets. We compare the performance of the new routing with ETX-optimal single path routing in both simulations and testbed-based experiments.
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| 10. |
- Gonga, António, et al.
(författare)
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Revisiting multi-channel communication to mitigate interference and link dynamics in wireless sensor networks
- 2012
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Ingår i: Proceedings - IEEE International Conference on Distributed Computing in Sensor Systems, DCOSS 2012. - : IEEE Computer Society. - 9780769547077 ; , s. 186-193
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Konferensbidrag (refereegranskat)abstract
- Multichannel communication has been proposed as alternative to adaptive (single-channel) routing protocols for mitigating the impact of interference and link dynamics in wireless sensor networks. While several studies have advocated features of both techniques (not without running up against contradicting arguments) a comprehensive study that aligns these results is still lacking. This paper aims at filling this gap. We present an experimental test bed setup used to perform extensive measurements for both single-channel and multichannel communication. We first analyze single-channel and multichannel communication over a single-hop in terms of packet reception ratio, maximum burst loss, temporal correlation of losses, and loss correlations across channels. Results show that multichannel communication with channel hopping significantly reduces link burstiness and packet loss correlation. For multi-hop networks, multi-channel communication and adaptive routing show similar end-to-end reliability in dense topologies, while multichannel communication can outperform adaptive routing in sparse networks with bursty links.
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