55 research outputs found

    Computer Science at the University of Helsinki 1998

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    Unsupervised adaptation for acceleration-based activity recognition: Robustness to sensor displacement and rotation

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    A common assumption in activity recognition is that the system remains unchanged between its design and its posterior operation. However, many factors affect the data distribution between two different experimental sessions. One of these factors is the potential change in the sensor location (e.g. due to replacement or slippage) affecting the classification performance. Assuming that changes in the sensor placement mainly result in shifts in the feature distributions, we propose an unsupervised adaptive classifier that calibrates itself using an online version of expectation-maximisation. Tests using three activity recognition scenarios show that the proposed adaptive algorithm is robust against shift in the feature space due to sensor displacement and rotation. Moreover, since the method estimates the change in the feature distribution it can also be used to roughly evaluate the reliability of the system during online operation

    A Survey on platoon-based vehicular cyber-physical systems

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    Vehicles on the road with some common interests can cooperatively form a platoon-based driving pattern, in which a vehicle follows another one and maintains a small and nearly constant distance to the preceding vehicle. It has been proved that, compared to driving individually, such a platoon-based driving pattern can significantly improve the road capacity and energy efficiency. Moreover, with the emerging vehicular adhoc network (VANET), the performance of platoon in terms of road capacity, safety and energy efficiency, etc., can be further improved. On the other hand, the physical dynamics of vehicles inside the platoon can also affect the performance of VANET. Such a complex system can be considered as a platoon-based vehicular cyber-physical system (VCPS), which has attracted significant attention recently. In this paper, we present a comprehensive survey on platoon-based VCPS. We first review the related work of platoon-based VCPS. We then introduce two elementary techniques involved in platoon-based VCPS: the vehicular networking architecture and standards, and traffic dynamics, respectively. We further discuss the fundamental issues in platoon-based VCPS, including vehicle platooning/clustering, cooperative adaptive cruise control (CACC), platoon-based vehicular communications, etc., and all of which are characterized by the tight coupled relationship between traffic dynamics and VANET behaviors. Since system verification is critical to VCPS development, we also give an overview of VCPS simulation tools. Finally, we share our view on some open issues that may lead to new research directions

    Unwinding Ariadne's Identity Thread: Privacy Risks with Fitness Trackers and Online Social Networks

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    The recent expansion of Internet of Things (IoT) and the growing trends towards a healthier lifestyle, have been followed by a proliferation in the use of fitness-trackers in our daily life. These wearable IoT devices combined with the extensive use by individuals of Online Social Networks (OSNs) have raised many security and privacy concerns. Individuals enrich the content of their online posts with their physical performance and attendance at sporting events, without considering the plausible risks that this may result in. This paper aims to examine the potential exposure of users' identity that is caused by information that they share online and personal data that are stored by their fitness-trackers. We approach the privacy concerns that arise by building an interactive tool. This tool models online information shared by individuals and elaborates on how they might be exposed to the unwanted leakage of further personal data. The tool also illustrates the privacy risks that arise from information that people expose, which could be exploited by malicious parties such as fraudsters, stalkers and other online and offline criminals. To understand the level of users' awareness concerning their identity exposure when engaging with such devices and online services, we also have conducted a qualitative analysis and present our findings here

    Who wrote this scientific text?

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    The IEEE bibliographic database contains a number of proven duplications with indication of the original paper(s) copied. This corpus is used to test a method for the detection of hidden intertextuality (commonly named "plagiarism"). The intertextual distance, combined with the sliding window and with various classification techniques, identifies these duplications with a very low risk of error. These experiments also show that several factors blur the identity of the scientific author, including variable group authorship and the high levels of intertextuality accepted, and sometimes desired, in scientific papers on the same topic

    7. GI/ITG KuVS FachgesprÀch Drahtlose Sensornetze

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    In dem vorliegenden Tagungsband sind die BeitrĂ€ge des FachgesprĂ€chs Drahtlose Sensornetze 2008 zusammengefasst. Ziel dieses FachgesprĂ€chs ist es, Wissenschaftlerinnen und Wissenschaftler aus diesem Gebiet die Möglichkeit zu einem informellen Austausch zu geben – wobei immer auch Teilnehmer aus der Industrieforschung willkommen sind, die auch in diesem Jahr wieder teilnehmen.Das FachgesprĂ€ch ist eine betont informelle Veranstaltung der GI/ITG-Fachgruppe „Kommunikation und Verteilte Systeme“ (www.kuvs.de). Es ist ausdrĂŒcklich keine weitere Konferenz mit ihrem großen Overhead und der Anforderung, fertige und möglichst „wasserdichte“ Ergebnisse zu prĂ€sentieren, sondern es dient auch ganz explizit dazu, mit Neueinsteigern auf der Suche nach ihrem Thema zu diskutieren und herauszufinden, wo die Herausforderungen an die zukĂŒnftige Forschung ĂŒberhaupt liegen.Das FachgesprĂ€ch Drahtlose Sensornetze 2008 findet in Berlin statt, in den RĂ€umen der Freien UniversitĂ€t Berlin, aber in Kooperation mit der ScatterWeb GmbH. Auch dies ein Novum, es zeigt, dass das FachgesprĂ€ch doch deutlich mehr als nur ein nettes Beisammensein unter einem Motto ist.FĂŒr die Organisation des Rahmens und der Abendveranstaltung gebĂŒhrt Dank den beiden Mitgliedern im Organisationskomitee, Kirsten Terfloth und Georg Wittenburg, aber auch Stefanie Bahe, welche die redaktionelle Betreuung des Tagungsbands ĂŒbernommen hat, vielen anderen Mitgliedern der AG Technische Informatik der FU Berlin und natĂŒrlich auch ihrem Leiter, Prof. Jochen Schiller

    Performance and energy efficiency in wireless self-organized networks

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    L'intertextualité dans les publications scientifiques

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    La base de donnĂ©es bibliographiques de l'IEEE contient un certain nombre de duplications avĂ©rĂ©es avec indication des originaux copiĂ©s. Ce corpus est utilisĂ© pour tester une mĂ©thode d'attribution d'auteur. La combinaison de la distance intertextuelle avec la fenĂȘtre glissante et diverses techniques de classification permet d'identifier ces duplications avec un risque d'erreur trĂšs faible. Cette expĂ©rience montre Ă©galement que plusieurs facteurs brouillent l'identitĂ© de l'auteur scientifique, notamment des collectifs de chercheurs Ă  gĂ©omĂ©trie variable et une forte dose d'intertextualitĂ© acceptĂ©e voire recherchĂ©e
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