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  • 1.
    Abrahamsson, Henrik
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ben Abdesslem, Fehmi
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ahlgren, Bengt
    RISE - Research Institutes of Sweden, ICT, SICS.
    Björkman, Mats
    Mälardalen University, Sweden.
    Brunstrom, Anna
    Karlstad University, Sweden.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Selecting Operator in 3G/4G Networks for Time-Critical C-ITS Applications2018Conference paper (Refereed)
  • 2.
    Abrahamsson, Henrik
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ben Abdesslem, Fehmi
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ahlgren, Bengt
    RISE - Research Institutes of Sweden, ICT, SICS.
    Brunstrom, Anna
    Karlstad University, Sweden.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Björkman, Mats
    Mälardalen University, Sweden.
    Connected Vehicles in Cellular Networks: Multi-access versus Single-access Performance2018Conference paper (Refereed)
    Abstract [en]

    Connected vehicles can make roads traffic safer andmore efficient, but require the mobile networks to handle timecriticalapplications. Using the MONROE mobile broadbandmeasurement testbed we conduct a multi-access measurementstudy on buses. The objective is to understand what networkperformance connected vehicles can expect in today’s mobilenetworks, in terms of transaction times and availability. The goalis also to understand to what extent access to several operatorsin parallel can improve communication performance.In our measurement experiments we repeatedly transfer warningmessages from moving buses to a stationary server. Wetriplicate the messages and always perform three transactionsin parallel over three different cellular operators. This creates adataset with which we can compare the operators in an objectiveway and with which we can study the potential for multi-access.In this paper we use the triple-access dataset to evaluate singleaccessselection strategies, where one operator is chosen for eachtransaction. We show that if we have access to three operatorsand for each transaction choose the operator with best accesstechnology and best signal quality then we can significantlyimprove availability and transaction times compared to theindividual operators. The median transaction time improves with6% compared to the best single operator and with 61% comparedto the worst single operator. The 90-percentile transaction timeimproves with 23% compared to the best single operator andwith 65% compared to the worst single operator.

  • 3.
    Ahlgren, Bengt
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Grinnemo, Karl-Johan
    Karlstad University, Sweden.
    Abrahamsson, Henrik
    RISE - Research Institutes of Sweden, ICT, SICS.
    Brunstrom, Anna
    Karlstad University, Sweden.
    Hurtig, Per
    Karlstad University, Sweden.
    Latency-aware Multipath Scheduling in Information-centric Networks2019In: Proceedings of the 15th Swedish National Computer Networking Workshop (SNCNW), 2019Conference paper (Other academic)
    Abstract [en]

    We present the latency-aware multipath scheduler ZQTRTT that takes advantage of the multipath opportunities in information-centric networking. The goal of the scheduler is to use the (single) lowest latency path for transaction-oriented flows, and use multiple paths for bulk data flows. A new estimator called zero queue time ratio is used for scheduling over multiple paths. The objective is to distribute the flow over the paths so that the zero queue time ratio is equal on the paths, that is, so that each path is ‘pushed’ equally hard by the flow without creating unwanted queueing. We make an initial evaluation using simulation that shows that the scheduler meets our objectives.

  • 4.
    Allison, R.S.
    et al.
    York University, Canada.
    Brunnstrom, Kjell
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Chandler, D.M.
    Shizuoka University, Japan.
    Colett, H.
    Intel Corp, USA.
    Corriveau, P.
    Intel Corp, USA.
    Daly, S.
    Dolby Laboratories Inc, USA.
    Goel, J.
    Qualcomm Technologies, USA.
    Long, J.Y.
    Intel Corp, USA.
    Wilcox, L.M.
    York University, Canada.
    Yaacob, Y.
    Shizuoka University, Japan.
    Yang, S. N.
    Pacific University, USA.
    Zhang, Y.
    Xi’an Jiaotong University, China.
    Perspectives on the definition of visually lossless quality for mobile and large format displays2018In: Journal of Electronic Imaging, ISSN 10179909, Vol. 27, no 5, article id 053035Article in journal (Refereed)
    Abstract [en]

    Advances in imaging and display engineering have given rise to new and improved image and videoapplications that aim to maximize visual quality under given resource constraints (e.g., power, bandwidth).Because the human visual system is an imperfect sensor, the images/videos can be represented in a mathematicallylossy fashion but with enough fidelity that the losses are visually imperceptible—commonly termed“visually lossless.” Although a great deal of research has focused on gaining a better understanding ofthe limits of human vision when viewing natural images/video, a universally or even largely accepted definitionof visually lossless remains elusive. Differences in testing methodologies, research objectives, and targetapplications have led to multiple ad-hoc definitions that are often difficult to compare to or otherwise employ inother settings. We present a compendium of technical experiments relating to both vision science and visualquality testing that together explore the research and business perspectives of visually lossless image quality,as well as review recent scientific advances. Together, the studies presented in this paper suggest that a singledefinition of visually lossless quality might not be appropriate; rather, a better goal would be to establish varyinglevels of visually lossless quality that can be quantified in terms of the testing paradigm.

  • 5. Aramrattana, Maytheewat
    et al.
    Larsson, Tony
    Jansson, Jonas
    Dimensions of Cooperative Driving, ITS and Automation2015In: Intelligent Vehicles Symposium (IV), 2015Conference paper (Other academic)
  • 6.
    Ben Abdesslem, Fehmi
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Abrahamsson, Henrik
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ahlgren, Bengt
    RISE - Research Institutes of Sweden, ICT, SICS.
    Measuring Mobile Network Multi-Access for Time-Critical C-ITS Applications2018Conference paper (Refereed)
    Abstract [en]

    Cooperative Intelligent Transport Systems (C-ITS)make road traffic safer and more efficient, but require the mobilenetworks to handle time-critical applications. While some applicationsmay need new dedicated communications technologiessuch as IEEE 802.11p or 5G, other applications can use currentcellular networks. This study evaluates the performance that connectedvehicles can expect from existing networks, and estimatesthe potential gain of multi-access by simultaneously transmittingover several operators. We upload time-critical warning messagesfrom buses in Sweden, and characterise transaction times andnetwork availability. We conduct the experiments with differentprotocols: UDP, TCP, and HTTPS. Our results show that whenusing UDP, the median transaction time for sending a typicalwarning message is 135 ms. We also show that multi-access canbring this value down to 73 ms. For time-critical applicationsrequiring transaction times under 200 ms, multi-access canincrease availability of the network from to 57.4% to 92.0%.

  • 7.
    Bosse, Sebastian
    et al.
    Fraunhofer, Germany.
    Brunnstrom, Kjell
    RISE - Research Institutes of Sweden, ICT, Acreo. Mid Sweden University, Sweden.
    Arndt, Sebastian
    NTNU Norwegian University of Science and Technology, Norway.
    Martini, Maria G.
    Kingston University, UK.
    Ramzan, Naeem
    University of the West of Scotland, UK.
    Engelke, Ulrich
    CSIRO, Australia.
    A common framework for the evaluation of psychophysiological visualquality assessment2019In: Quality and User Experience, ISSN 2366-0139, E-ISSN 2366-0147, Vol. 4, no 3Article in journal (Refereed)
    Abstract [en]

    The assessment of perceived quality based on psychophysiological methods recently gained attraction as it potentiallyovercomes certain flaws of psychophysical approaches. Although studies report promising results, it is not possible toarrive at decisive and comparable conclusions that recommend the use of one or another method for a specific applicationor research question. The video quality expert group started a project on psychophysiological quality assessment to studythese novel approaches and to develop a test plan that enables more systematic research. This test plan comprises of a specificallydesigned set of quality annotated video sequences, suggestions for psychophysiological methods to be studied inquality assessment, and recommendations for the documentation and publications of test results. The test plan is presentedin this article.

  • 8.
    Brunnstrom, Kjell
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. Mid Sweden University, Sweden.
    Barkowsky, Marcus
    University of Applied Sciences, Germany.
    Statistical quality of experience analysis: on planning the sample size and statistical significance testing2018In: Journal of Electronic Imaging (JEI), ISSN 1017-9909, E-ISSN 1560-229X, Vol. 27, no 5, article id 053013Article in journal (Refereed)
    Abstract [en]

    This paper analyzes how an experimenter can balance errors in subjective video quality tests betweenthe statistical power of finding an effect if it is there and not claiming that an effect is there if the effect is not there,i.e., balancing Type I and Type II errors. The risk of committing Type I errors increases with the number ofcomparisons that are performed in statistical tests. We will show that when controlling for this and at thesame time keeping the power of the experiment at a reasonably high level, it is unlikely that the number oftest subjects that are normally used and recommended by the International Telecommunication Union (ITU),i.e., 15 is sufficient but the number used by the Video Quality Experts Group (VQEG), i.e., 24 is more likelyto be sufficient. Examples will also be given for the influence of Type I error on the statistical significance ofcomparing objective metrics by correlation. We also present a comparison between parametric and nonparametricstatistics. The comparison targets the question whether we would reach different conclusions on the statisticaldifference between the video quality ratings of different video clips in a subjective test, based on thecomparison between the student T-test and the Mann–Whitney U-test. We found that there was hardly a differencewhen few comparisons are compensated for, i.e., then almost the same conclusions are reached. Whenthe number of comparisons is increased, then larger and larger differences between the two methods arerevealed. In these cases, the parametric T-test gives clearly more significant cases, than the nonparametrictest, which makes it more important to investigate whether the assumptions are met for performing a certaintest.

  • 9.
    Brunnstrom, Kjell
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo. Mid Sweden University, Sweden.
    Dima, Elijs
    Mid Sweden University, Sweden.
    Andersson, Mattias
    Mid Sweden University, Sweden.
    Sjöström, Mårten
    Mid Sweden University, Sweden.
    Qureshi, Tahir
    HIAB, Sweden.
    Johanson, Mathias
    Alkit Communications AB, Sweden.
    Quality of Experience of hand controller latency in a Virtual Reality simulator2019In: Human Vision and Electronic Imaging 2019 / [ed] Damon Chandler, Mark McCourt and Jeffrey Mulligan, 2019, article id 3068450Conference paper (Refereed)
    Abstract [en]

    In this study, we investigate a VR simulator of a forestry crane used for loading logs onto a truck, mainly looking at Quality of Experience (QoE) aspects that may be relevant for task completion, but also whether there are any discomfort related symptoms experienced during task execution. A QoE test has been designed to capture both the general subjective experience of using the simulator and to study task performance. Moreover, a specific focus has been to study the effects of latency on the subjective experience, with regards to delays in the crane control interface. A formal subjective study has been performed where we have added controlled delays to the hand controller (joystick) signals. The added delays ranged from 0 ms to 800 ms. We found no significant effects of delays on the task performance on any scales up to 200 ms. A significant negative effect was found for 800 ms added delay. The Symptoms reported in the Simulator Sickness Questionnaire (SSQ) was significantly higher for all the symptom groups, but a majority of the participants reported only slight symptoms. Two out of thirty test persons stopped the test before finishing due to their symptoms.

  • 10.
    Brunnström, Kjell
    et al.
    Mid Sweden University, Sweden.
    Sjöström, Mårten
    Mid Sweden University, Sweden.
    Muhammad, Imran
    HIAB AB, Sweden;Mid Sweden University, Sweden.
    Magnus, Pettersson
    HIAB AB, Sweden.
    Johanson, Mathias
    Alkit Communications AB, Sweden.
    Quality of Experience for a Virtual Reality simulator2018In: Human Vision and Electronic Imaging 2018 / [ed] Rogowitz, B.;Pappas, T.;De Ridder H., The Society for Imaging Science and Technology, 2018Conference paper (Refereed)
    Abstract [en]

    In this study, we investigate a VR simulator of a forestry crane used for loading logs onto a truck, mainly looking at Quality of Experience (QoE) aspects that may be relevant for task completion, but also whether there are any discomfort related symptoms experienced during task execution. The QoE test has been designed to capture both the general subjective experience of using the simulator and to study task completion rate. Moreover, a specific focus has been to study the effects of latency on the subjective experience, with regards both to delays in the crane control interface as well as lag in the visual scene rendering in the head mounted display (HMD). Two larger formal subjective studies have been performed: one with the VR-system as it is and one where we have added controlled delay to the display update and to the joystick signals. The baseline study shows that most people are more or less happy with the VR-system and that it does not have strong effects on any symptoms as listed in the Simulator Sickness Questionnaire (SSQ). In the delay study we found significant effects on Comfort Quality and Immersion Quality for higher Display delay (30 ms), but very small impact of joystick delay. Furthermore, the Display delay had strong influence on the symptoms in the SSQ, and causing test subjects to decide not to continue with the complete experiments. We found that this was especially connected to the longer added Display delays (≥ 20 ms).

  • 11. Chen, Lei
    et al.
    Englund, Cristofer
    RISE, Swedish ICT, Viktoria. Halmstad University, Sweden; Chalmers University of Technology, Sweden.
    Cooperative Intersection Management: A Survey2016In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 17, no 2, p. 570-586, article id 7244203Article in journal (Refereed)
    Abstract [en]

    Intersection management is one of the most challenging problems within the transport system. Traffic light-based methods have been efficient but are not able to deal with the growing mobility and social challenges. On the other hand, the advancements of automation and communications have enabled cooperative intersection management, where road users, infrastructure, and traffic control centers are able to communicate and coordinate the traffic safely and efficiently. Major techniques and solutions for cooperative intersections are surveyed in this paper for both signalized and nonsignalized intersections, whereas focuses are put on the latter. Cooperative methods, including time slots and space reservation, trajectory planning, and virtual traffic lights, are discussed in detail. Vehicle collision warning and avoidance methods are discussed to deal with uncertainties. Concerning vulnerable road users, pedestrian collision avoidance methods are discussed. In addition, an introduction to major projects related to cooperative intersection management is presented. A further discussion of the presented works is given with highlights of future research topics. This paper serves as a comprehensive survey of the field, aiming at stimulating new methods and accelerating the advancement of automated and cooperative intersections.

  • 12. Chen, Lei
    et al.
    Englund, Cristofer
    RISE, Swedish ICT, Viktoria.
    Cooperative ITS - EU standards to accelerate cooperative mobility2014In: 2014 International Conference on Connected Vehicles and Expo, ICCVE 2014, 2014, p. 681-686Conference paper (Refereed)
    Abstract [en]

    With intensive research and field operational tests over the intelligent transportation area and the advancements of information and communication technologies, intelligent transportation systems reach the stage of deployment. EU focuses on cooperative intelligent transportation systems and confirms the finalization of the first release of the standards, paving the way for deployment in the coming years. This paper presents the concept of EU's cooperative intelligent transportation systems and describes in detail the functional architecture, together with highlights of related standardsthat have been finalized in Release 1. Latest updates of the cooperative intelligent transportation systems are provided for both industry and academia, aiming at helping to accelerate cooperative mobility.

  • 13.
    Chen, Lei
    et al.
    RISE, Swedish ICT, Viktoria.
    Habibovic, Azra
    RISE, Swedish ICT, Viktoria.
    Englund, Cristofer
    RISE, Swedish ICT, Viktoria. Halmstad University, Sweden.
    Voronov, Alexey
    RISE, Swedish ICT, Viktoria.
    Walter, Anders
    Swedish Road Administration, Sweden.
    Coordinating Dangerous Goods Vehicles: C-ITS Applications for Safe Road Tunnels2015In: 2015 IEEE Intelligent Vehicles Symposium (IV), 2015, p. 156-161, article id 7225679Conference paper (Refereed)
    Abstract [en]

    Despite the existing regulation efforts and measures, vehicles with dangerous goods still pose significant risks on public safety, especially in road tunnels. Solutions based on cooperative intelligent transportation system (C-ITS) are promising measures, however, they have received limited attention. We propose C-ITS applications that coordinate dangerous goods vehicles to minimize the risk by maintaining safe distances between them in road tunnels. Different mechanisms, including global centralized coordination, global distributed coordination, and local coordination, are proposed and investigated. A preliminary simulation is performed and demonstrates their effectiveness.

  • 14.
    Dima, Elijs
    et al.
    Mid Sweden University, Sweden.
    Brunnstrom, Kjell
    RISE - Research Institutes of Sweden, ICT, Acreo. Mid Sweden University, Sweden.
    Sjöström, Mårten
    Mid Sweden University, Sweden.
    Andersson, Mattias
    Mid Sweden University, Sweden.
    Edlund, Joakim
    Mid Sweden University, Sweden.
    Johanson, Mathias
    Alkit Communications AB, Sweden.
    Qureshi, Tahir
    HIAB AB, Sweden.
    View Position Impact on QoE in an Immersive Telepresence System for Remote Operation2019In: 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX), Berlin, Germany: IEEE , 2019Conference paper (Refereed)
    Abstract [en]

    In this paper, we investigate how different viewingpositions affect a user’s Quality of Experience (QoE) and performancein an immersive telepresence system. A QoE experimenthas been conducted with 27 participants to assess the generalsubjective experience and the performance of remotely operatinga toy excavator. Two view positions have been tested, an overheadand a ground-level view, respectively, which encourage relianceon stereoscopic depth cues to different extents for accurate operation.Results demonstrate a significant difference between groundand overhead views: the ground view increased the perceiveddifficulty of the task, whereas the overhead view increased theperceived accomplishment as well as the objective performanceof the task. The perceived helpfulness of the overhead view wasalso significant according to the participants.

  • 15.
    Englund, Cristofer
    et al.
    RISE, Swedish ICT, Viktoria.
    Chen, Lei
    Voronov, Alexey
    Cooperative speed harmonization for efficient road utilization2014In: Nets4Cars, 2014Conference paper (Other academic)
  • 16.
    Englund, Cristofer
    et al.
    RISE, Swedish ICT, Viktoria.
    Nilsson, Josef
    Lidström, Kristoffer
    Cooperative ITS application development through semantic standardization2013In: FASTZero 2013, 2013Conference paper (Refereed)
  • 17.
    Kakkar, Aditya
    et al.
    KTH Royal Institute of Technology, Sweden.
    Pang, Xiaodan
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Ozolins, Oskars
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Schatz, Richard
    KTH Royal Institute of Technology, Sweden.
    Navarro, Jaime Rodrigo
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Louchet, Hadrien
    VPIphotonics GmBH, Germany.
    Jacobsen, Gunnar
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    A path to use large linewidth LO in 28 Gbd 16-QAM metro links2015In: 2015 European Conference on Optical Communication (ECOC), 2015, article id 7341948Conference paper (Refereed)
    Abstract [en]

    We experimentally investigate the possibility to mitigate local oscillator induced Equalization Enhanced Phase Noise penalty. The results pave the way for the use of even 10 MHz linewidth local oscillator lasers in 28 Gbd 16-QAM metro links.

  • 18.
    Navarro, Jaime Rodrigo
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Kakkar, Aditya
    KTH Royal Institute of Technology, Sweden.
    Pang, Xiaodan
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Ozolins, Oskars
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Schatz, Richard
    KTH Royal Institute of Technology, Sweden.
    Olmedo, Miguel Iglesias
    KTH Royal Institute of Technology, Sweden.
    Jacobsen, Gunnar
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    Carrier Phase Recovery Algorithms for Coherent Optical Circular mQAM Systems2016In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 34, no 11, p. 2717-2723Article in journal (Refereed)
    Abstract [en]

    The phase noise tolerance of circular multilevel quadrature amplitude modulation (C-mQAM) constellations employing different carrier phase recovery (CPR) algorithms is studied. A differential decoding scheme and a bit mapping for this type of constellations are proposed. A novel CPR scheme for C-mQAM constellations is also presented. The particular distribution of the constellation points in a C-mQAM signal is exploited to reduce the required Nth power for the removal of the modulation component by a factor of two. Hence, the computational complexity of the proposed algorithm is drastically reduced. The combined linewidth symbol duration product (??Ts) tolerance of different CPR algorithms for C-mQAM constellations is studied and compared with the proposed CPR scheme. The results are analyzed at 3.8e-3 and 1e-2 bit error rate forward error correction limits. The proposed CPR scheme achieves similar ??Ts tolerance compared to single stage BPS algorithm while its computational complexity is reduced by group factors of 27.2 | 32.3, and 30.5 | 32.6 (in the form of multipliers | adders) for C-16QAM and C-64QAM, respectively.

  • 19. Nilsson, Josef
    et al.
    Strandén, Lars
    Englund, Cristofer
    RISE, Swedish ICT, Viktoria.
    Fault model for cooperative semi-automated vehicles2013In: 20th ITS World Congress, Tokyo 2013. Proceedings, 2013, p. 1-10, article id 2058.Conference paper (Refereed)
    Abstract [en]

    This paper presents a fault model for vehicle functions that includes communication devices for inter-vehicle cooperation. In particular, the fault model addresses vehicles where automation has partially replaced the driver, i.e., semi-automated cooperative vehicles. Components considered in the fault model include human drivers, communication systems, sensors, actuators, and control units. A description of faults in cooperative systems in general is complemented with an identification of errors in a platooning system. The identification has revealed systematic faults in software and human errors in the interaction between the system and the driver.

  • 20.
    Ozolins, O.
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    An, Y.
    Lali-Dastjerdi, Z.
    Ding, Y.
    Bobrovs, V.
    Ivanovs, G.
    Peucheret, C.
    Cascadability of silicon microring resonators for 40-Gbit/s OOK and DPSK optical signals2012In: 2012 Asia Communications and Photonics Conference (ACP), 2012, p. 1-3Conference paper (Refereed)
    Abstract [en]

    The cascadability of a single silicon micro-ring resonator for CSRZ-OOK and CSRZ-DPSK signals is experimentally demonstrated at 40 Gbit/s for the first time. Error-free performance is obtained for both modulation formats after 5 cascaded resonators.

  • 21.
    Ozolins, Oskars
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Pang, Xiodan
    RISE - Research Institutes of Sweden, ICT.
    Olmedo, Miguel Iglesias
    KTH Royal Institute of Technology, Sweden.
    Udalcovs, Aleksejs
    RISE - Research Institutes of Sweden, ICT, Acreo. KTH Royal Institute of Technology, Sweden.
    Kakkar, Aditya
    KTH Royal Institute of Technology, Sweden.
    Navarro, Jaime Rodrigo
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Schatz, Richard
    KTH Royal Institute of Technology, Sweden.
    Westergren, Urban
    KTH Royal Institute of Technology, Sweden.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    Jacobsen, Gunnar
    RISE - Research Institutes of Sweden, ICT, Acreo.
    “High-speed optical and wireless transmission - challenges and achievements”2016In: 2016 Advances in Wireless and Optical Communications (RTUWO), 2016Conference paper (Refereed)
    Abstract [en]

    The cloud services together with the huge size datasets are driving demand for bandwidth in datacenters. The 400 Gbps client-side links are demanding a solution. The intensity modulation and direct-detection systems together with integrated semiconductor lasers and modulators appear as promising solution in four optical lanes at 100 Gbps net rate in order to reduce complexity, size, power consumption and cost.

  • 22.
    Pang, X.
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Jia, S.
    DTU Technical University of Denmark, Denmark; Tianjin University, China.
    Ozolins, O.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Yu, X.
    Zhejiang University, China.
    Hu, H.
    DTU Technical University of Denmark, Denmark.
    Marcon, L.
    KTH Royal Institute of Technology, Sweden.
    Guan, P.
    DTU Technical University of Denmark, Denmark.
    Ros, F. D.
    DTU Technical University of Denmark, Denmark.
    Popov, S.
    DTU Technical University of Denmark, Denmark.
    Jacobsen, G.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Galili, M.
    DTU Technical University of Denmark, Denmark.
    Morioka, T.
    DTU Technical University of Denmark, Denmark.
    Zibar, D.
    DTU Technical University of Denmark, Denmark.
    Oxenlowe, L. K.
    DTU Technical University of Denmark, Denmark.
    Single channel 106 Gbit/s 16QAM wireless transmission in the 0.4 THz band2017In: 2017 Optical Fiber Communications Conference and Exhibition (OFC), 2017Conference paper (Refereed)
    Abstract [en]

    We experimentally demonstrate a single channel 32-GBd 16QAM THz wireless link operating in the 0.4 THz band. Post-FEC net data rate of 106 Gbit/s is successfully achieved without any spatial/frequency multiplexing.

  • 23.
    Rao, Akhila
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Steinert, Rebecca
    RISE - Research Institutes of Sweden, ICT, SICS.
    Probabilistic multi-RAT performance abstractionsManuscript (preprint) (Other academic)
    Abstract [en]

    Development towards 5G has introduced difficultchallenges in effectively managing and operating heterogeneousinfrastructures under highly varying network conditions. En-abling, for example, unified coordination and management ofradio resources across coexisting, multiple radio access technolo-gies (multi-RAT), require efficient representation using high-levelabstractions of the radio network performance and state. Withoutsuch abstractions, users and networks cannot harvest the fullpotential of increased resource density and connectivity optionsresulting in failure to meet the ambitions of 5G.We present a generic probabilistic approach for unified estima-tion of performance variability based on attainable throughputof UDP traffic in multi-RATs, and evaluate the applicability inan interface selection control case (involving WiFi and LTE)based on obtaining probabilistic user performance guarantees.From simulations we observe that both users and operators cansignificantly benefit from this improved service availability at lownetwork cost. Initial results indicate 1) 116% fewer performanceviolations and 2) 20% fewer performance violations with areduction by 35 times in the number of handovers, comparedto naive and state-of-the-art baselines, respectively.

  • 24.
    Shih Yang, Lin
    et al.
    Halmstad University, Sweden.
    Vinel, Alexey
    Halmstad University, Sweden.
    Englund, Cristofer
    RISE, Swedish ICT, Viktoria.
    Chen, Lei
    Adaptive Wavelength Adjustment (AWLA) for Cooperative Speed Harmonization2014In: VNC, 2014, p. 113-114Conference paper (Refereed)
    Abstract [en]

    Traffic merge on express-ways creates bottlenecks for traffic flow that potentially lead to traffic jams, especially in dense traffic. Cooperative speed harmonization (CSH), where vehicles are grouped and associated to virtual speed waves for group-wise joining at intersections, is proven to be efficient for on-ramp traffic merge. Based on CSH and considering variations of traffic density from joining roads, an adaptive wavelength adjustment (AWLA) mechanism is proposed in this paper. AWLA extends CSH by dynamically adjusting the length of segments in virtual waves according to the traffic densities of the joining roads. Therefore, roads with denser traffic may have larger segments to carry more vehicles through the intersection, which may improve the overall performance. Simulation results have shown that AWLA can achieve lower CO2 emissions and shorter travel time compared to CSH with static segment settings.

  • 25.
    Tiloca, Marco
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    De Guglielmo, Domenico
    University of Pisa, Italy.
    Dini, Gianluca
    University of Pisa, Italy.
    Anastasi, Giuseppe
    University of Pisa, Italy.
    Das, Sajal K.
    Missouri University of Science and Technology, USA.
    DISH: DIstributed SHuffling against selective jamming attack in IEEE 802.15.4e TSCH networks2018In: ACM transactions on sensor networks, ISSN 1550-4867, E-ISSN 1550-4859, Vol. 15, no 1, article id a3Article in journal (Refereed)
    Abstract [en]

    The MAC standard amendment IEEE 802.15.4e is designed to meet the requirements of industrial and critical applications. In particular, the Time Slotted Channel Hopping (TSCH) mode divides time into periodic, equally-sized, slotframes composed of transmission timeslots. Then, it combines timeslotted access with multi-channel and channel hopping capabilities, providing large network capacity, high reliability and predictable latency, while ensuring energy efficiency. Since every network node considers the same timeslots at each sloframe and selects physical channels according to a periodic function, TSCH produces a steady channel utilization pattern. This can be exploited by a selective jammer to entirely thwart communications of a victim node, in a way that is stealthy, effective and extremely energy efficient. This paper shows how a selective jamming attack can be successfully performed even though TSCH uses the IEEE 802.15.4e security services. Furthermore, we propose DISH, a countermeasure which randomly permutes the timeslot and channel utilization patterns at every slotframe in a consistent and completely distributed way, without requiring any additional message exchange. We have implemented DISH for the Contiki OS and tested its effectiveness onTelosB sensor nodes. Quantitative analysis for different network configurations shows that DISH effectively contrasts selective jamming with negligible performance penalty.

  • 26.
    Tiloca, Marco
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dini, Gianluca
    University of Pisa, Italy.
    Rizki, Kiki
    RISE - Research Institutes of Sweden, ICT, SICS.
    Raza, Shahid
    RISE - Research Institutes of Sweden, ICT, SICS.
    Group rekeying based on member join history2019In: International Journal of Information Security, ISSN 1615-5262, E-ISSN 1615-5270Article in journal (Refereed)
    Abstract [en]

    This paper presents GREP, a novel group rekeying scheme that leverages the history of join events in order to achieve efficiency and high scalability. GREP rekeys thegroup with only two broadcast messages, hence displaying an overhead which is small, constant and independent of the group size. Also, GREP efficiently recovers the group from collusion attack with no recourse to total member reinitialization. Even in the very unlikely worst case, collusion recovery displays a smooth impact on performance that gradually increases with the attack severity. We implemented GREP for the Contiki OS and tested it on different resource-constrained platforms. Our analytical and experimental evaluation confirm that GREP is efficient, highly scalable and deployable also on constrained nodes. The paper extends a previous version of this work, especially through additional security analysis, treatise of probabilities for worst case collusion, and experimental evaluation of performance.

  • 27.
    Tiloca, Marco
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Höglund, Rikard
    RISE - Research Institutes of Sweden, ICT, SICS.
    Al Atiiq, Syafiq
    KTH Royal Institute of Technology, Sweden.
    SARDOS: Self-Adaptive Reaction against Denial of Service in the Internet of Things2018Conference paper (Refereed)
    Abstract [en]

    Denial of Service (DoS) is a common and severe security issue in computer networks. Typical DoS attacks overload servers with bogus requests, induce them to worthlessly commit resources, and even make them unable to serve legitimate clients. This is especially relevant in Internet of Things scenarios, where servers are particularly exposed and often equipped with limited resources. Although most countermeasures focus on detection and mitigation, they do not react to dynamically adapt victims' behavior, while at the same time preserving service availability. This paper presents SARDOS, a reactive security service that leverages detection mechanisms from different communication layers, and adaptively changes the operative behavior of victim servers while preserving service availability. We experimentally evaluated SARDOS with a prototype implementation running on an underclocked Raspberry Pi server. Our results show that, when running SARDOS, a server under attack displays considerably lower memory and CPU usage, while still ensuring (best-effort) fulfillment of legitimate requests.

  • 28.
    van Kasteren, Anouk
    RISE - Research Institutes of Sweden, ICT, Acreo. University of Technology Eindhoven.
    The Contribution of Eye Tracking to Quality of Experience Assessment of 360-degree video2019Independent thesis Advanced level (degree of Master (Two Years)), 180 HE creditsStudent thesis
    Abstract [en]

    The research domain on the Quality of Experience (QoE) of 2D video streaming has been well established. However, a new video format is emerging and gaining popularity and availability: VR 360-degree video. The processing and transmission of 360-degree videos brings along new challenges such as large bandwidth requirements and the occurrence of different distortions. The viewing experience is also substantially different from 2D video, it offers more interactive freedom on the viewing angle but can also be more demanding and cause cybersickness. Further research on the QoE of 360-videos specifically is thus required.The first goal of this thesis is to complement earlier research by (Tran, Ngoc, Pham, Jung, and Thank, 2017) testing the effects of quality degradation, freezing, and content on the QoE of 360-videos. The second goal is to test the contribution of visual attention as influence factor in the QoE assessment. Data will be gathered through subjective tests where participants watch degraded versions of 360-videos through an HMD with integrated eye-tracking sensors. After each video they will answer questions regarding their quality perception, experience, perceptual load, and cybersickness.Results of the first part show overall rather low QoE ratings and it decreases even more as quality is degraded and freezing events are added. Cyber sickness was found not to be an issue. The effects of the manipulation on visual attention were minimal. Attention was mainly directed by content, but also by surprising elements. The addition of eye-tracking metrics did not further explain individual differences in subjective ratings. Nevertheless it was found that looking at moving objects increased the negative effect of freezing events and made participants less sensitive for quality distortions. The results of this thesis alone are not enough to successfully regard visual attention as an influence factor in 360-video.

  • 29.
    Voronov, Alexey
    et al.
    RISE, Swedish ICT, Viktoria.
    Englund, Cristofer
    RISE, Swedish ICT, Viktoria. Halmstad University, Sweden.
    Hoang Bengtsson, Hoai
    RISE, Swedish ICT, Viktoria.
    Chen, Lei
    RISE, Swedish ICT, Viktoria.
    Ploeg, Jeroen
    TNO Netherlands Organisation for Applied Scientific Research, The Netherlands.
    de Jongh, Jan
    TNO Netherlands Organisation for Applied Scientific Research, The Netherlands.
    van de Sluis, Jacco
    TNO Netherlands Organisation for Applied Scientific Research, The Netherlands.
    Interactive Test Tool for Interoperable C-ITS Development2015In: 2015 IEEE 18th International Conference on Intelligent Transportation Systems, 2015, p. 1713-1718Conference paper (Refereed)
    Abstract [en]

    This paper presents the architecture of an Interactive Test Tool (ITT) for interoperability testing of Cooperative Intelligent Transport Systems (C-ITS). Cooperative systems are developed by different manufacturers at different locations, which makes interoperability testing a tedious task. Up until now, interoperability testing is performed during physical meetings where the C-ITS devices are placed within range of wireless communication, and messages are exchanged. The ITT allows distributed (e.g. over Internet) interoperability testing starting from the network Transport Layer and all the way up to the Application Layer, e.g. to platooning. ITT clients can be implemented as Hardware-in-the-Loop, thus allowing to combine physical and virtual vehicles. Since the ITT considers each client as a black box, manufacturers can test together without revealing internal implementations to each other. The architecture of the ITT allows users to easily switch between physical wireless networking and virtual ITT networking. Therefore, only one implementation of the ITS communication stack is required for both development and testing, which reduces the work overhead and ensures that the stack that is used during the testing is the one deployed in the real world.

  • 30. Xiong, M.
    et al.
    Ozolins, O.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Ding, Y.
    Huang, B.
    An, Y.
    Ou, H.
    Peucheret, C.
    Zhang, X.
    41.6 Gb/s RZ-DPSK to NRZ-DPSK format conversion in a microring resonator2012In: 2012 17th Opto-Electronics and Communications Conference, 2012, p. 891-892Conference paper (Refereed)
    Abstract [en]

    RZ-DPSK to NRZ-DPSK format conversion in a silicon microring resonator is demonstrated experimentally for the first time at 41.6 Gb/s. The converted signal eye diagrams and bit-error-rate measurements show the good performance of the scheme.

1 - 30 of 30
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