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| 2. |
- Ekberg, Pontus, et al.
(författare)
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A distributed swarm-intelligent localization for sensor networks with mobile nodes
- 2011
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Ingår i: Proc. 7th International Wireless Communications and Mobile Computing Conference. - Piscataway, NJ : IEEE. - 9781424495399 ; , s. 83-88
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Konferensbidrag (refereegranskat)abstract
- We present a novel distributed localization algorithm, called Swarm-Intelligent Localization (SIL), for computing the physical locations of nodes in wireless sensor networks. The algorithm assumes that only a small fraction of the nodes have a priori knowledge of their positions, and that noisy distance measurements are available between all neighboring nodes. The algorithm has no explicit global state and it can handle nodes that are both mobile and that can arrive in the network at any time. SIL works in two different phases, a coarse phase where nodes compute rough positions for themselves based on information about remote anchors, and a fine phase where nodes iteratively refine their positions from the coarse phase by collaborating with their neighbors. The average computational complexity per node running SIL is very low, namely constant in the network size and linear in the connectivity of the network. We evaluate the algorithm through extensive simulations. The results indicate that SIL is able to compute accurate positions for the majority of nodes in a wide range of network topologies and settings, and that it can handle difficulties such as large distance measurement errors and low network connectivity.
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- Elsts, Atis, et al.
(författare)
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A Case for Node-Local Runtime Parameter Adaptation in Wireless Sensor Networks
- 2014
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Ingår i: Proc. 10th Swedish National Computer Networking Workshop.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The challenges posed to wireless sensor networks by the environments they are deployed cannot always be predicted beforehand. Therefore, adaptive behavior at the run-time may be required to achieve good reliability and energy-efficiency. We present a node-local runtime adaptation algorithm that adapts the over-the-air message encoding based on presence of weak links and external interference in the immediate neighborhood of the node. Evaluation with a network simulator shows that this algorithm leads to significant network-wide reduction of radio duty cycle under specific radio transmission failure models.
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- Guerreiro, João, et al.
(författare)
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Privacy-aware probabilistic sampling for data collection in wireless sensor networks
- 2011
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Ingår i: Proc. 7th International Wireless Communications and Mobile Computing Conference. - Piscataway, NJ : IEEE conference proceedings. - 9781424495399 ; , s. 314-319
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Konferensbidrag (refereegranskat)abstract
- The rising popularity of web services and their applications to sensor networks enables real-time data collection and queries by users. Unlike traditional periodic data collection, the traffic patterns generated from real-time data collection may expose the interests of users or the locations of unusual events to the attackers. To provide privacy in data collection, we propose a novel probabilistic sampling mechanism that can hide user queries and unusual events in the network, while supporting both routine and on-demand data reporting. Our goal is to prevent attackers from locating the unusual events and identifying interests of users by eavesdropping and analyzing the network traffic. In our probabilistic sampling scheme, the data are carefully reported at random times in order to mask the unusual events and user queries. In the meantime, our scheme can provide users with high data accuracy at minimized communication overheads. Extensive simulations have been conducted to evaluate the security strength, data accuracy and communication overheads of the proposed scheme.
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| 13. |
- Hermans, Frederik, et al.
(författare)
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Poster Abstract:Supporting Heterogeneous LCD/Camera Links
- 2014. - 10
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Ingår i: Proc. 13th International Symposium on Information Processing in Sensor Networks. - Piscataway, NJ : IEEE Press. - 9781479931460 ; , s. 289-290
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Konferensbidrag (refereegranskat)abstract
- Visible light communication over LCD/camera links offers a potential complement to traditional RF communication technology such as WiFi or cellular networks. However, the heterogeneity in receivers (e.g., mobile phone cameras) presents a challenge because the receivers differ widely in resolution, distance to the transmitter (LCD), and other factors, and therefore they differ in channel quality. We are researching a communication scheme in which each receiver can decode as much data from an LCD's transmission as the receiver's channel supports. The core idea is to encode the payload into an image's frequency representation rather than directly into pixels. We have successfully transmitted data using a prototype implementation and are currently investigating appropriate channel models.
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| 15. |
- Hermans, Frederik
(författare)
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Sensor Networks and Their Radio Environment : On Testbeds, Interference, and Broken Packets
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sensor networks consist of small sensing devices that collaboratively fulfill a sensing task, such as monitoring the soil in an agricultural field or measuring vital signs in a marathon runner. To avoid cumbersome and expensive cabling, nodes in a sensor network are powered by batteries and communicate wirelessly. As a consequence of the latter, a sensor network's communication is affected by its radio environment, i.e., the environment's propagation characteristics and the presence of other radio devices. This thesis addresses three issues related to the impact of the radio environment on sensor networks.Firstly, in order to draw conclusions from experimental results, it is necessary to assess how the environment and the experiment infrastructure affect the results. We design a sensor network testbed, dubbed Sensei-UU, to be easily relocatable. By performing an experiment in different environments, a researcher can asses the environments’ impact on results. We further augment Sensei-UU with support for mobile nodes. The implemented mobility approach adds only little variance to results, and therefore enables repeatable experiments with mobility. The repeatability of experiments increases the confidence in conclusions drawn from them.Secondly, sensor networks may experience poor communication performance due to cross-technology radio interference, especially in office and residential environments. We consider the problem of detecting and classifying the type of interference a sensor network is exposed to. We find that different sources of interference each leave a characteristic "fingerprint" on individual, corrupt 802.15.4 packets. We design and implement the SoNIC system that enables sensor nodes to classify interference using these fingerprints. SoNIC supports accurate classification in both a controlled and an uncontrolled environment.Finally, we consider transmission errors in an outdoor sensor network. In such an environment, errors occur despite the absence of interference if the signal-to-noise ratio at a receiver is too low. We study the characteristics of corrupt packets collected from an outdoor sensor network deployment. We find that content transformation in corrupt packets follows a specific pattern, and that most corrupt packets contain only few errors. We propose that the pattern may be useful for applications that can operate on inexact data, because it reduces the uncertainty associated with a corrupt packet.
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| 16. |
- Hermans, Frederik, et al.
(författare)
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SoNIC: Classifying Interference in 802.15.4 Sensor Networks
- 2013. - 11
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Ingår i: Proc. 12th International Conference on Information Processing in Sensor Networks. - New York, NY, USA : ACM. - 9781450319591 ; , s. 55-66
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Konferensbidrag (refereegranskat)abstract
- Sensor networks that operate in the unlicensed 2.4 GHz frequency band suffer cross-technology radio interference from a variety of devices, e.g., Bluetooth headsets, laptops using WiFi, or microwave ovens. Such interference has been shown to significantly degrade network performance. We present SoNIC, a system that enables resource-limited sensor nodes to detect the type of interference they are exposed to and select an appropriate mitigation strategy. The key insight underlying SoNIC is that different interferers disrupt individual 802.15.4 packets in characteristic ways that can be detected by sensor nodes. In contrast to existing approaches to interference detection, SoNIC does not rely on active spectrum sampling or additional hardware, making it lightweight and energy-efficient. In an office environment with multiple interferers, a sensor node running SoNIC correctly detects the predominant interferer 87% of the time. To show how sensor networks can benefit from SoNIC, we add it to a mobile sink application to improve the application's packet reception ratio under interference.
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| 26. |
- Man, Yemao, 1987, et al.
(författare)
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Energy-efficient automatic location-triggered applications on smartphones
- 2014
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Ingår i: Computer Communications. - : Elsevier BV. - 1873-703X .- 0140-3664. ; 50, s. 29-40
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Tidskriftsartikel (refereegranskat)abstract
- With the prevalence of localization techniques in smartphones, location-based applications on mobiles have become increasingly popular. However, only minorities of applications can be triggered automatically by the predefined locations of interest without any human interaction. One reason is that the inevitable operation of location detection by GPS is power-intensive. While existing work has focused on energy efficiency in continuous location tracking, energy-efficient location detection for matching predefined location of interest remains to be further explored. This paper proposes a unified framework that supports energy-efficient location detection for automatic location-triggered applications. Our framework triggers desired events only when the user is approaching the predefined locations of interest. Besides the efforts we make to reduce the number of GPS updates by cooperating with other types of on-device sensors, the framework also aims to coordinate multiple location-triggered applications to further reduce energy consumption on location updates. We implemented our framework as a middleware in the Android operating system and conducted extensive real experiments. The experimental results demonstrate that our framework can reduce the number of GPS requests and low the energy consumption of the smartphones significantly.
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| 27. |
- Mumey, Brendan, et al.
(författare)
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Ubiquitous sensor data collection with mobile users
- 2014
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Ingår i: Proc. 3rd International Conference on Computing, Networking and Communications. - Piscataway, NJ : IEEE Press. - 9781479923588 ; , s. 561-566
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Konferensbidrag (refereegranskat)
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| 33. |
- Ngai, Edith C.-H., et al.
(författare)
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Quality-of-information-aware data collection for mobile sensor networks
- 2014
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Ingår i: Pervasive and Mobile Computing. - : Elsevier BV. - 1574-1192 .- 1873-1589. ; 11, s. 203-215
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Tidskriftsartikel (refereegranskat)abstract
- Quality of information (QoI) in sensor networks measures information attributes such as precision, timeliness, completeness, and relevance of data ultimately delivered to users. It is a challenge to provide the required QoI in mobile sensor networks given the large scale and complexity of the networks with heterogeneous mobile and sensing devices. In this paper, we provide a comprehensive study on major QoI metrics for mobile sensor networks and discuss how QoI-aware data collection can be achieved. The cases with mobile sensors, mobile sinks, and mobile mules carrying data and their impact on QoI are discussed in detail. Mobility creates challenges in terms of timeliness but also opportunities in increased coverage and relevance. In a case study, we design a QoI-aware publish/subscribe system for mobile sensor networks. Users can subscribe to obtain information about events of interest by specifying the target area, sensing context, etc. The subscriptions and the sensing data are delivered to relevant sensors and users by location-based routing. We also discuss techniques that can be applied to further enhance the QoI in our publish/subscribe system. Simulation results demonstrate that the users can receive their subscribed data successfully with low communication overhead. Our publish/subscribe system can also handle mobility of clients smoothly without causing any data loss.
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| 34. |
- Niroumand, Kamyar, et al.
(författare)
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Poster abstract : SADSense: Personalized mobile sensing for seasonal effects on health
- 2014
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Ingår i: IPSN 2014 - Proceedings of the 13th International Symposium on Information Processing in Sensor Networks (Part of CPS Week). - Piscataway, NJ : IEEE Computer Society. - 9781479931460 ; , s. 295-296
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- People's moods and activities are heavily affected by their environment, which changes significantly throughout the year. The variable of daylight hours is huge for countries in extreme latitudes, impacting the population's health and well-being. In this paper, we present a smartphone application that efficiently and accurately measures a person's light exposure, mood and activity levels. We performed a preliminary study to show effective data collection using on-board sensors in the mobile phones. © 2014 IEEE.
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| 37. |
- Rodhe, Ioana, et al.
(författare)
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On location privacy and quality of information in participatory sensing
- 2012
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Ingår i: Proc. 8th ACM Symposium on QoS and Security for Wireless and Mobile Networks. - New York : ACM Press. - 9781450316194 ; , s. 55-62
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Konferensbidrag (refereegranskat)abstract
- Participatory sensing applications typically bind sensor data to locations. Location privacy preserving mechanisms protecting the location of users introduce therefore an uncertainty in the collected data distributions. We consider two strategies to reconstruct a data distribution after k-anonymity has been applied to the users' location information. We investigate how different parameters for the location privacy preserving mechanism influence both the quality of information and the location privacy of the users. Our results show that the cloak area resulted from applying k-anonymity has a higher impact on both the quality of information and the location privacy than the number of users, k, that are cloaked together.
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