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  • 1. Achtzehn, Andreas
    et al.
    Benenson, Zinaida
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology. Datorteknik. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Implementing Agreement Protocols in Sensor2006In: The Second International Workshop on Wireless and Sensor Networks Security (WSNS'06), 2006Conference paper (Refereed)
    Abstract [en]

    We investigate application of agreement protocols tolerating malicious failures in sensor networks. We identify several scenarios where agreement can be used, and report on our experience with implementing an agreement protocol.

  • 2.
    Achtzehn, Andreas
    et al.
    RWTH Aachen.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rodhe, Ioana
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    ARPD: Asynchronous random key predistribution in the LEAP framework for Wireless Sensor Networks2007In: 3rd IEEE International Workshop on Wireless and Sensor Networks Security (IEEE WSNS 2007), 2007Conference paper (Refereed)
    Abstract [en]

    In the LEAP framework for wireless sensor networks a set of keys is used to secure communication. LEAP distinguishes between unicast (pairwise) communication, group (cluster) communication and global (broadcast) communication. The keys used in pairwise communication are derived from an initial key KI that nodes are equipped with prior to deployment

    and that is deleted after link setup. Further keys are distributed encrypted with these pairwise keys. If the initial key is ever disclosed, the whole network is compromised.

    To lower the threat of KI disclosure, we present a novel KI -less scheme for key predistribution. Our scheme is based on random key redistribution, and proves to perform better in medium sized networks than previous proposals. It is resilient against node capture attacks and allows node to node authentication. Attacks against overlying protocols in the network are more difficult with this scheme.

    We have conducted computations to show the feasibility of our scheme for networks up to a size of 1000 nodes. By introducing a key reuse system we are able to increase the probability of a successful link setup. We have included a security analysis that discusses our scheme’s resistance against commonly known attacks.

  • 3.
    Ahlén, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Ahlgren, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Grönroos, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Katardjiev, Ilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Presentation of the VINN Excellence Center for Wireless Sensor Networks (WISENET)2008In: Conference on Radio Science (RVK08), Växjö, 2008Conference paper (Refereed)
  • 4.
    Bastani, Saeed
    et al.
    The University of Sydney.
    Landfeldt, Björn
    Lund University.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    A social node model for realising information dissemination strategies in delay tolerant networks2012In: Proceedings of the 15th ACM international conference on Modeling, analysis and simulation of wireless and mobile systems, New york: ACM Press, 2012, p. 79-88Conference paper (Refereed)
    Abstract [en]

    In Delay Tolerant Networks (DTNs) as an emerging content dissemination platform, mobile nodes opportunistically exchange content as they meet, with the intent of disseminating content among nodes that share common interests. During a meeting, nodes can exchange both content of direct interest to themselves as well as content that is of interest to a larger set of nodes that may be encountered in the future. The utility of DTN is governed by the content exchange opportunity (the amount of content that can be exchanged during a meeting) as well as the selection of content to be exchanged in order to maximise the interest nodes will have in information they are exposed to. Considering that there is a cost associated with the content exchange (e.g. battery usage, buffer occupancy or consumed transmission opportunity) the aim for nodes participating in content dissemination should be to maximise their payoff. In this paper, we contribute a generic framework for describing the characteristics of content exchange among participating nodes in a network. We incorporate a distributed information popularity measurement and the pairwise interaction of nodes modelled as a bargaining problem. The outcome of this process is the fair split up of dwelling time as a network resource and the selection of which content objects to exchange in order to maximise the nodes’ payoff. The framework is generally intended to be used as a capstone for investigation of content dissemination properties and various content exchange strategies in a DTN, a topic addressed in this paper and experiments conducted to validate the function and correctness of the proposed framework. 

  • 5.
    Beneson, Zinaida
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Freiling, Felix C.
    Pfitzmann, Birgit
    Rohner, Christian
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Waidner, Michael
    Verifiable Agreement: Limits of Non-Repudiation in Mobile Peer-to-Peer Ad Hoc Networks2006In: Third European Workshop on Security and Privacy in Ad hoc and Sensor Networks, 2006Conference paper (Refereed)
    Abstract [en]

    We introduce verifiable agreement as a fundamental service for securing mobile peer-to-peer ad hoc networks, and investigate its solvability. Verifiability of a protocol result means that the participants can prove that the protocol reached a particular result to any third party (the verifier) which was not present in the network at the time of the protocol execution.

  • 6.
    Bjurefors, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Nordström, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Interest dissemination in a searchable data-centric opportunistic network2010In: Proc. European Wireless Conference: EW 2010, Piscataway, NJ: IEEE , 2010, p. 889-895Conference paper (Other academic)
  • 7.
    Bjurefors, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Haggle Testbed: a Testbed for Opportunistic Networks2011In: In Proceedings of the 7th Swedish National Computer Networking Workshop, 2011Conference paper (Refereed)
  • 8.
    Bjurefors, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Tavakoli, Sam
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Congestion Avoidance in a Data-Centric Opportunistic Network2011In: Proceedings of the 2011 ACM SIGCOMM Workshop on Information-Centric Networking (ICN-2011), 2011Conference paper (Refereed)
  • 9.
    Bjurefors, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Karaliopoulos, Markourios
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Smith, Paul
    Theodoropoulos, George
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Resilience and Opportunistic Forwarding: Beyond Average Value Analysis2014In: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 48, no SI, p. 111-120Article in journal (Refereed)
    Abstract [en]

    Opportunistic networks are systems with highly distributed operation, relying on the altruistic cooperation of highly heterogeneous, and not always software and hardware-compatible, user nodes. Moreover, the absence of central coordination and control makes them vulnerable to malicious attacks. In this paper, we study the resilience of popular forwarding protocols to a representative set of challenges to their normal operation. These include jamming locally disturbing message transfer between nodes, hardware/software failures and incompatibility among nodes rendering contact opportunities useless, and free-riding phenomena. We first formulate and promote the metric envelope concept as a tool for assessing the resilience of opportunistic forwarding schemes. Metric envelopes depart from the standard practice of average value analysis and explicitly account for the differentiated challenge impact due to node heterogeneity (device capabilities, mobility) and attackers’ intelligence. We then propose heuristics to generate worst- and best-case challenge realization scenarios and approximate the lower and upper bounds of the metric envelopes. Finally, we demonstrate the methodology in assessing the resilience of three popular forwarding protocols in the presence of the three challenges, and under a comprehensive range of mobility patterns. The metric envelope approach provides better insights into the level of protection path diversity and message replication provide against different challenges, and enables more informed choices in opportunistic forwarding when network resilience becomes important.

  • 10.
    Bjurefors, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Karaliopoulos, Merkourios
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Smith, Paul
    Theodoropoulos, George
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Resilience and Opportunistic Forwarding: Beyond Average Value Analysis2013In: CHANTS '13 Proceedings of the 8th ACM MobiCom workshop on Challenged networks, 2013Conference paper (Refereed)
    Abstract [en]

    Opportunistic networks are systems with highly distributed operation, relying on the altruistic cooperation of heterogeneous, and not always software- and hardware-compatible user nodes. Moreover, the absence of central control makes them vulnerable to malicious attacks. In this paper, we take a fresh look at the resilience of opportunistic forwarding to these challenges. In particular, we introduce and promote the use of metric envelopes as a resilience assessment tool. Metric envelopes depart from the standard practice of average value analysis and explicitly account for the differentiated impact that a challenge may have on the forwarding performance due to node heterogeneity (device capabilities, mobility) and attackers’ intelligence. The use of metric envelopes is demonstrated in the case of three challenges: jamming, hardware/software failures and incompatibilities, and free-riding phenomena. For each challenge, we first devise heuristics to generate worst- and best-case realization scenarios that can approximate the metric envelopes. Then we derive the envelopes of common performance metrics for three popular forwarding protocols under a comprehensive range of mobility patterns. The metric envelope approach enables more informed choices in opportunistic forwarding whenever network resilience considerations become important. 

  • 11.
    Bjurefors, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology. Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Phanse, Kaustubh
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology. Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Wibling, Oskar
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology. Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology. Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Testbed and Methodology for Experimental Evaluation of Opportunistic Networks2007In: 7th Scandinavian Workshop on Wireless Ad-hoc Networks (ADHOC'07), 2007Conference paper (Refereed)
  • 12.
    Cambazoglu, Volkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Towards adaptive zero-knowledge protocols: A case study with Fiat–Shamir identification protocol2013In: Proc. 9th Swedish National Computer Networking Workshop, 2013, p. 67-70Conference paper (Refereed)
    Abstract [en]

    Interactive zero-knowledge protocols are used as identification protocols. The protocols are executed in rounds, with security being increased with every round. This allows for a trade-off between security and performance to adapt the protocol to the requirements of the scenario. We experimentally investigate the Fiat–Shamir identification protocol on machines and networks with different performance characteristics. We find that the delay of the protocol highly depends on network latency and upload bandwidth. Computation time becomes more visible, when the protocol transmits little amount of data via a low latency network. We also experience that the impact of the sizes of the variables on the delay of the protocol is less than the number of rounds', which are interior factors in the protocol.

  • 13.
    Cambazoglu, Volkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Victor, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    The impact of trace and adversary models on location privacy provided by K-anonymity2012In: Proc. 1st Workshop on Measurement, Privacy, and Mobility, New York: ACM Press, 2012, article id 6Conference paper (Refereed)
  • 14. Catalán Rivas, Victoria
    et al.
    Fröjd, Emil
    Holmberg, Tobias
    Ragnarsson, Felix
    Rick, Elsa
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Corneo, Lorenzo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Varshney, Ambuj
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Environmental Control at the Edge2018Conference paper (Other academic)
  • 15.
    Corneo, Lorenzo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Age of Information-Aware Scheduling for Timely and Scalable Internet of Things Applications2019In: IEEE Conference On Computer Communications (IEEE INFOCOM 2019), 2019, p. 2476-2484Conference paper (Refereed)
    Abstract [en]

    We consider large scale Internet of Things applications requesting data from physical devices. We study the problem of timely dissemination of sensor data towards applications with freshness requirements by means of a cache. We aim to minimize direct access to the possibly battery powered physical devices, yet improving Age of Information as a data freshness metric. We propose an Age of Information-aware scheduling policy for the physical device to push sensor updates to the caches located in cloud data centers. Such policy groups application requests based on freshness thresholds, thereby reduces the number of requests and threshold misses, and accounts for delay variation. The policy is incrementally introduced as we study its behavior over ideal and more realistic communication links with delay variation. We numerically evaluate the proposed policy against a simple yet widely used periodic schedule. We show that our informed schedule outperforms the periodic schedule even under high delay variations.

  • 16.
    Eriksson, Gustav
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Varshney, Ambuj
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Dancila, Dragos
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Towards Long-range Backscatter Communication with Tunnel Diode Reflection Amplifier2018Conference paper (Other academic)
  • 17.
    Feeney, Laura Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Hartung, Robert
    Technische Universitaet Braunschweig, Braunschweig, Germany.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Kulau, Ulf
    Technische Universitaet Braunschweig, Braunschweig, Germany.
    Wolf, Lars
    Technische Universitaet Braunschweig, Braunschweig, Germany.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Towards realistic lifetime estimation in battery-powered IoT devices2017In: Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems Article No. 67, Association for Computing Machinery (ACM), 2017, article id 67Conference paper (Refereed)
    Abstract [en]

    We describe a testbed for studying battery discharge behavior andthe lifetime of wireless devices under controlled temperature conditions and present preliminary measurement results.

  • 18.
    Feeney, Laura Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    A model for evaluating asynchronous protocols in Ad hoc Networks2006In: 6th Scandinavian Workshop on Wireless Ad-hoc Networks (ADHOC'06), 2006Conference paper (Refereed)
  • 19.
    Feeney, Laura Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Modeling Capacity in Ad Hoc Networks: Extended Poster Abstract2006In: : Poster Session Proceedings, 2006Conference paper (Refereed)
    Abstract [en]

    We describe a simple network model for efficiently simulating the CBR flow capacity of a multi-hop wireless network. The model is particularly intended for studying the behavior of asynchronous protocols, particularly power save protocols, where it is useful to examine many scheduling variations as well as many topologies and network configurations.

    We describe our experience using the model in some experiments in which we examine how the network performance is sensitive to the timing to scheduling variations induced by the operation of a simple power save protocol. We note that the model also seems seems suitable for combinatoric and probabilistic analysis, which is on-going work.

  • 20.
    Feeney, Laura Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Poster abstract: The feasibility of leveraging a power save protocol to improve performance in ad hoc networks2006In: The Twelfth Annual International Conference on Mobile Computing and Networking (Mobicom2006), 2006Conference paper (Refereed)
    Abstract [en]

    We discuss how the operation of an asynchronous power save protocol affects the scheduling of transmissions in an ad hoc network. We present simulation results that show that network capacity is sensitive to the random distribution of wakeup schedules. Finally, we discuss the implications of this result with respect to improving performance and speculate about potential new cross-layer architectures.

  • 21.
    Feeney, Laura Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Ahlgren, Bengt
    Leveraging a power save protocol to improve performance in ad hoc networks2007In: ACM SIGMOBILE Mobile Computing and Communications Review, ISSN 1559-1662, Vol. 11, no 2, p. 51-52Article in journal (Refereed)
    Abstract [en]

    Power save protocols reduce energy consumption in ad hoc and sensor networks by allowing nodes to put their network interface into a low power consumption sleep state. The power save protocol must allow neighboring nodes to establish intervals during which they are mutually awake and available to exchange traffic. Many such protocols are based on a coordinated election of a covering set that is responsible for buffering traffic for sleeping nodes, but uncoordinated (i.e. asynchronous) protocols have also proven an attractive option.

  • 22.
    Feeney, Laura Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology. Datorteknik. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Ahlgren, Bengt
    The impact of wakeup schedule distribution in asynchronous power save protocols on the performance of multihop wireless networks2007In: IEEE Wireless Communications and Networking Conference: WCNC 2007, 2007Conference paper (Refereed)
  • 23.
    Feeney, Laura Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Making batteries a first class element in the design and evaluation of embedded wireless systems2017In: Proc. 14th International Conference on Embedded Wireless Systems and Networks, ACM Digital Library, 2017, p. 242-243Conference paper (Refereed)
  • 24.
    Feeney, Laura Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Lindgren, Anders
    Andersson, Lars
    How do the dynamics of battery discharge affect sensor lifetime?2014In: 2014 11th Annual Conference on Wireless On-demand Network Systems and Services (WONS), Piscataway, NJ: IEEE , 2014, p. 49-56Conference paper (Refereed)
  • 25. Guerreiro, João
    et al.
    Ngai, Edith C.-H.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Privacy-aware probabilistic sampling for data collection in wireless sensor networks2011In: Proc. 7th International Wireless Communications and Mobile Computing Conference, Piscataway, NJ: IEEE conference proceedings, 2011, p. 314-319Conference paper (Refereed)
    Abstract [en]

    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.

  • 26.
    Hartung, Robert
    et al.
    Technical University -- Braunschweig.
    Käberich, Jan
    Technical University -- Braunschweig.
    Wolf, Lars C.
    Technical University -- Braunschweig.
    Feeney, Laura Marie
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    A Platform for Experiments with Energy Storage Devices for Low-power Wireless Networks2018In: Proc. 12th International Workshop on Wireless Network Testbeds, Experimental Evaluation & Characterization, New York: ACM Press, 2018, p. 68-76Conference paper (Refereed)
    Abstract [en]

    We present a hardware platform for performing experimental studies of energy storage devices for low power wireless networks. It is based on a low-cost custom card that can apply fine-grain synthetic loads ? both charge and discharge ? to a set of batteries or capacitors and measure their response in detail. Loads can be defined from a "live" trace of a running wireless device, from a recorded trace, or programmatically via a script. This approach makes it practical to run well controlled, large scale, long running experiments and to obtain high precision and accuracy. We describe two proof-of-concept experiments using rechargeable Li coin cells and capacitors to demonstrate the capabilities of our platform.

  • 27.
    Hartung, Robert
    et al.
    Technical University - Braunschweig.
    Käberich, Jan
    Technical University - Braunschweig.
    Wolf, Lars C.
    Technical University - Braunschweig.
    Feeney, Laura Marie
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Integration of a Platform for Energy Storage Experiments into a Generic Testbed Framework2018In: Proc. 12th International Workshop on Wireless Network Testbeds, Experimental Evaluation & Characterization, New York: ACM Press, 2018, p. 77-78Conference paper (Refereed)
  • 28.
    Hermans, Frederik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    McNamara, Liam
    Sörös, Gábor
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Ngai, Edith
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    FOCUS: Robust visual codes for everyone2016In: Proc. 14th International Conference on Mobile Systems, Applications, and Services, New York: ACM Press, 2016, p. 319-332Conference paper (Refereed)
  • 29.
    Hermans, Frederik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    McNamara, Liam
    Swedish Institute of Computer Science.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Ngai, Edith
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Supporting Heterogeneous LCD/Camera Links2014In: Proc. 13th International Symposium on Information Processing in Sensor Networks, Piscataway, NJ: IEEE Press, 2014, p. 289-290Conference paper (Refereed)
  • 30.
    Hermans, Frederik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Wennerström, Hjalmar
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    McNamara, Liam
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    All is not lost: Understanding and exploiting packet corruption in outdoor sensor networks2014In: Wireless Sensor Networks: EWSN 2014, Springer Berlin/Heidelberg, 2014, p. 116-132Conference paper (Refereed)
  • 31.
    Hilmia, Abdalah
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Hewage, Kasun
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Varshney, Ambuj
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. SICS, Stockholm, Sweden.
    Poster Abstract:BouKey: Location-Based Key Sharing Using Visible LightCommunication2016Conference paper (Refereed)
    Abstract [en]

    Visible Light Communication (VLC) is an emerging communication channel serving as a complement to traditional wireless communication. Visible light has many advantages over other communication channels like its inability to penetrate opaque objects. Securely sharing secret keys is a known problem in computer security. Sharing security keys using Radio Frequency (RF) communication is prone to sniffing attacks. In this paper, we introduce a system called BouKey which uses visible light to share keys. This makes BouKey immune to through the wall sniffing attacks. BouKey divides the key and shares it using multiple transmission bulbs allowing the key to be received in a specific area only. Our initial results show that the characteristics and height of the receiver, as well as the transmission angle play a key role in determining the shape and size of this area.

  • 32.
    Hossmann, Theus
    et al.
    ETH Zürich.
    Carta, Paolo
    ETH Zürich.
    Schatzmann, Dominik
    ETH Zürich.
    Legendre, Franck
    ETH Zürich.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Twitter in Disaster Mode: Security Architecture2011In: Conference on emerging Networking EXperiments and Technologies (CoNEXT): Special Workshop on the Internet and Disasters (SWID), Tokyo: ACM Press, 2011Conference paper (Refereed)
    Abstract [en]

    Recent natural disasters (earthquakes, floods, etc.) have shown that people heavily use platforms like Twitter to communicate and organize in emergencies. However, the fixed infrastructure supporting such communications may be temporarily wiped out. In such situations, the phones’ capabilities of infrastructure-less communication can fill in: By propagating data opportunistically (from phone to phone), tweets can still be spread, yet at the cost of delays.

    In this paper, we present Twimight and its network security extensions. Twimight is an open source Twitter client for Android phones featured with a “disaster mode”, which users enable upon losing connectivity. In the disaster mode, tweets are not sent to the Twitter server but stored on the phone, carried around as people move, and forwarded via Bluetooth when in proximity with other phones. However, switching from an online centralized application to a dis- tributed and delay-tolerant service relying on opportunistic communication requires rethinking the security architecture. We propose security extensions to offer comparable security in the disaster mode as in the normal mode to protect Twimight from basic attacks. We also propose a simple, yet efficient, anti-spam scheme to avoid users from being flooded with spam. Finally, we present a preliminary empirical performance evaluation of Twimight. 

  • 33.
    Hossmann, Theus
    et al.
    ETH Zürich.
    Legendre, Franck
    ETH Zürich.
    Carta, Paolo
    ETH Zürich.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Twitter in Disaster Mode: Opportunistic Communication and Distribution of Sensor Data in Emergencies2011In: ExtremeCom2011, ACM Press, 2011Conference paper (Refereed)
    Abstract [en]

    Recent events (earthquakes, floods, etc.) have shown that users heavily rely on online social networks (OSN) to communicate and organize during disasters and in their aftermath. In this paper, we discuss what features could be added to OSN apps for smart phones – for the example of Twitter – to make them even more useful for disaster situations. In particular, we consider cases where the fixed communication infrastructure is partially or totally wiped out and propose to equip regular Twitter apps with a disaster mode. The disaster mode relies on opportunistic communication and epidemic spreading of Tweets from phone to phone. Such “disaster-ready” applications would allow to resume (although limited) communication instantaneously and help distressed people to self-organize un- til regular communication networks are functioning again, or, temporary emergency communication infrastructure is installed.

    We argue why we believe that Twitter with its simplicity and versatile features (e.g., retweet and hashtag) is a good platform to support a variety of different situations and present Twimight, our disaster ready Twitter application. In addition, we propose Twimight as a platform for disseminating sensor data providing information such as locations of drinkable water sources. Eventually, we propose to rely on interest matching to scale Twitter hashtag-based searches in an opportunistic environment. The combination of these features make our opportunistic Twitter the ideal emergency kit in situations of disasters. We discuss and define the main implementation and research challenges (both technical and non- technical). 

  • 34.
    Hylamia, Abdullah
    et al.
    KTH Royal Inst Technol, Stockholm, Sweden.
    Varshney, Ambuj
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Soleiman, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Papadimitratos, Panagiotis
    KTH Royal Inst Technol, Stockholm, Sweden.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems. RISE SICS, Stockholm, Sweden.
    Demo: Towards Battery-free Radio Tomographic Imaging2018In: WISEC'18: PROCEEDINGS OF THE 11TH ACM CONFERENCE ON SECURITY & PRIVACY IN WIRELESS AND MOBILE NETWORKS, ASSOC COMPUTING MACHINERY , 2018, p. 293-295Conference paper (Refereed)
    Abstract [en]

    Radio Tomographic Imaging (RTI) enables novel radio frequency (RF) sensing applications such as intrusion detection systems by observing variations in radio links caused by human actions. RTI applications are, however, severely limited by the requirement to retrofit existing infrastructure with energy-expensive sensors. In this demonstration, we present our ongoing efforts to develop the first battery-free RTI system that operates on minuscule amounts of energy harvested from the ambient environment. Our system eliminates the energy-expensive components employed on state-of-the-art RTI systems achieving two orders of magnitude lower power consumption. Battery-free operation enables a sustainable deployment, as RTI sensors could be deployed for long periods of time with little maintenance effort. Our demonstration showcases an intrusion detection scenario enabled by our system.

  • 35.
    Hylamia, Sam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Poster: Tiek: Two-tier Authentication and Key Distribution for Wearable Devices2019Conference paper (Refereed)
  • 36.
    Hylamia, Sam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Yan, Wenqing
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Tiek: Two-tier Authentication and Key Distribution for Wearable Devices2019In: 15th International Conference on Wireless and MObile Computing, Networking and Communication (WiMob), Barcelona, 21-23 October, 2019., 2019Conference paper (Refereed)
    Abstract [en]

    Wearable devices, such as implantable medical devices and smart wearables, are becoming increasingly popular with applications that vary from casual activity monitoring to critical medical uses. Unsurprisingly, numerous security vulnerabilities have been found in this class of devices. Yet, research on physical measurement-based authentication and key distribution assumes that body-worn devices are benign and uncompromised. Tiek is a novel authentication and key distribution protocol which addresses this issue. We utilize two sources of randomness to perform device authentication and key distribution simultaneously but through separate means. This creates a two-tier authorization scheme that enables devices to join the network while protecting them from each other. We describe Tiek and analyze its security.

    The full text will be freely available from 2022-06-01 01:00
  • 37.
    Jacobsson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Comparing wireless flooding protocols using trace-based simulations2013In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, p. 169:1-15Article in journal (Refereed)
    Abstract [en]

    Most wireless multi-hop networks, such as ad hoc networks and wireless sensor networks, need network-wide broadcasting, which is best done with a flooding protocol. In this article, we use packet trace information from a real test-bed network to define a simulator for flooding protocol performance studies. Five protocols are compared using the simulator. Trace-based simulations promise to have the benefits of the simulator, such as reducing required work effort and repeatability but still produce results close to the real test-bed or deployment. We propose and evaluate different approaches on how to use collected trace data and how to tune the parameters to achieve the best possible accuracy in comparison with actual test-bed measurements. We study the resulting accuracy of the model so that performance studies know with what confidence a certain conclusion can be made. Using the new trace-based model and knowing its accuracy, we compare the five flooding protocols to gain additional insights into their performance. Finally, by modifying the trace data, we study how real-world effects, such as links with in-between qualities and asymmetric links, influence the different flooding protocols.

  • 38.
    Jacobsson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Estimating packet delivery ratio for arbitrary packet sizes over wireless links2015In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 19, no 4, p. 609-612Article in journal (Refereed)
    Abstract [en]

    Real life measurements show that on a given wireless link, the packet delivery ratio of different packet lengths varies with longer packets experiencing lower delivery ratios. In this letter, we measure this effect in detail over several different wireless links and technologies. Our results show that the current models are not entirely correct. Hence, we propose a simple modification that rectifies this behavior. Using this new model, we look at how link quality estimation methods can be enhanced to include this modification. Our study shows that the use of two different packet lengths or simple compensation can be used to achieve significantly better estimation of link quality.

  • 39.
    Jacobsson, Martin
    et al.
    KTH Royal Inst Technol, Dept Biomed Engn & Hlth Syst, Halsovagen 11C, S-14157 Huddinge, Sweden.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Link quality estimation for arbitrary packet sizes over wireless links using packet reception events2019In: International Journal of Communication Systems, ISSN 1074-5351, E-ISSN 1099-1131, Vol. 32, no 16, article id e4115Article in journal (Refereed)
    Abstract [en]

    The packet error rate of wireless links is known to increase with the length of packets. Yet, packet length is rarely taken into account in protocols and algorithms estimating the packet error rate. Still, it is an important factor that higher layer protocols need to be aware of. In this article, we systematically measure the relationship between packet length and packet error rate over a wide range of wireless links and technologies. On the basis of our measurements, we propose a simple empirical model that can capture this behavior. Using this model, multiple methods are proposed that can estimate the packet error rate for any packet length by sampling the link. We consider methods based on hello packets with controlled packet lengths as well as data packets, where the transmitted packet lengths cannot be controlled. We investigate the accuracy of the different estimation methods in various situations and show how they are able to predict the delivery ratio for different packet sizes.

  • 40.
    Karaliopoulos, Merkourios
    et al.
    National and Kapodistrian University of Athens.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Trace-based performance analysis of opportunistic forwarding under imperfect node cooperation2012In: Proceedings of the 31st Annual IEEE International Conference on Computer Communications (IEEE INFOCOM 2012), Orlando: IEEE Communications Society, 2012Conference paper (Refereed)
    Abstract [en]

    The paper proposes an innovative method for the performance analysis of opportunistic forwarding protocols over files logging mobile node encounters (contact traces). The method is modular and evolves in three steps. It first carries out contact filtering to isolate contacts that constitute message forwarding opportunities for given message coordinates and forwarding rules. It then draws on graph expansion techniques to capture these forwarding contacts into sparse space-time graph constructs. Finally, it runs standard shortest path algorithms over these constructs and derives typical performance metrics such as message delivery delay and path hopcount. The method is flexible in that it can easily assess the protocol operation under various expressions of imperfect node cooperation. We describe it in detail, analyze its complexity, and evaluate it against discrete event simulations for three representative randomized forwarding schemes. The match with the simulation results is excellent and obtained with run times up to three orders of size smaller than the duration of the simulations, thus rendering our method a valuable tool for the performance analysis of opportunistic forwarding schemes. 

  • 41.
    Kaveh, Amin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Magnani, Matteo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Comparing node degrees in probabilistic networks2019In: Journal of Complex Networks, E-ISSN 2051-1329, Vol. 7, no 5, p. 749-763Article in journal (Refereed)
  • 42.
    Kaveh, Amin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Magnani, Matteo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Defining and measuring probabilistic ego networks2019In: Applied Network Science Journal, E-ISSN 2364-8228Article in journal (Other academic)
  • 43.
    Marti, Sergio Angel
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Rohner, Christian
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Wireless Communication in Orienteering2005Report (Other (popular scientific, debate etc.))
  • 44.
    McNamara, Liam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Mining Conversations of Geographically Changing Users2012In: Proceedings of the World Wide Web 2012 Workshop on Social Web for Disaster (SWDM2012), Lion, 2012Conference paper (Refereed)
    Abstract [en]

    In recent disaster events, social media has proven to be an effective communication tool for affected people. The corpus of messages contains valuable information about the situation on the ground, needs, and locations of victims. We propose a methodology to extract significant aspects of user discussions to better inform responders and enable an appropriate response.

    The methodology combines location/movement based selection of user together with text mining (term frequency inverse document frequency) to identify important topics of conversation in a dynamic geographic network. We further suggest that both topics and movement patterns change during a disaster, which further allows for identification of new trends.

    When applied to an area where a disaster has recently occured this approach can provide useful insights into where people are located, where they are going and what they saying during those movements. 

  • 45.
    Mehrparvar, Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Bjurefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Smith, Paul
    AIT Austrian Institute of Technology.
    On Resilience in Opportunistic Networks2012In: 8th Swedish National Computer Networking Workshop SNCNW 2012, 2012Conference paper (Refereed)
  • 46.
    Nordström, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Aldman, Daniel
    Bjurefors, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Using Search to Enhance Picture Sharing with Mobile Phones: Demo2009In: ACM MobiSys, Krakow: ACM , 2009Conference paper (Refereed)
  • 47.
    Nordström, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    A Search-based Network Architecture for Content-oriented and Opportunistic CommunicationArticle in journal (Refereed)
    Abstract [en]

    It is well recognized that the current Internet architecture does not properly accommodate content oriented and opportunistic communication. A key to supporting such communication is access to networking primitives that allow temporal and spatial decoupling between senders and receivers. In this paper we present Haggle, a clean slate architecture that is designed from the ground up with such primitives in mind. Haggle rids itself of the traditional layered namespaces and instead introduces a unified and expressive metadata namespace that spans, not only hosts and file systems, but also networks.

    This unified metadata namespace enables resolution through Google-inspired searching, allowing flexible and late binding between content and receivers. We define a set of networking primitives around search based resolution and describe how they provide novel solutions to many problems associated with the targeted scenarios. We describe our architecture and reference implementation that illustrate the feasibility of our approach.

     

  • 48.
    Nordström, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    A Search-based Network Architecture for Mobile Devices2009Report (Other academic)
  • 49.
    Nordström, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Haggle: A Data-centric Network Architecture for Mobile Devices2009Conference paper (Other academic)
    Abstract [en]

    Delay-tolerant and opportunistic networks relax the traditional assumption of end-to-end connectivity. Such networks are therefore suitable for content dissemination in sparsely connected regions of the world, and for complementing existing infrastructure by operating cost-free, high bandwidth, albeit high latency, content delivery services.

    In this work we argue, however, that content dissemination in the above contexts requires us to revisit delay-tolerant communication at the architectural level, looking at multiple issues such as naming and addressing, congestion control and application interfaces. We propose a new architecture, called Haggle, that leverages the principles of search, as known from desktop operating systems and the Web, in order to achieve truly data-centric communication. Searching is naturally data-centric and embeds principles, such as ranking, that can be used to bind data to interested receivers and to prioritize the data to send during node encounters. We herein give an overview of the Haggle architecture and its basic design.

  • 50.
    Nordström, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Gunningberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Wibling, Oskar
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    A Cross-Environment Study of Routing Protocols for Wireless Multi-hop NetworksManuscript (Other academic)
12 1 - 50 of 82
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