80 research outputs found

    Life at the 49th Parallel: Media, Space, and the Liminal Perspective

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    North of Empire: Essays on the Cultural Technologies of Space by Jody Berland. Durham, NC: Duke University Press, 2009. Pp. 408, 33 illustrations. 94.95cloth,94.95 cloth, 26.95 paper

    Laserstrukturierung von Mikroprägewerkzeugen und Abformung beugungsoptisch wirksamer Gitterstrukturen

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    In dieser Arbeit werden Ergebnisse der Untersuchungen zur Laserstrukturierung von Prägewerkezeugen sowie zur Abformung von Gitterstrukturen mit Gitterperioden von kleiner gleich 2 µm in verschiedene Folien und Werkstoffverbunde präsentiert und diskutiert. Die hierfür entwickelte Kombination von Laserprozessen wird erläutert. Des Weiteren sind die auf Basis der experimentellen Untersuchungen ermittelten Parameterräume aufgezeigt und in Bezug zu theoretischen Beschreibungsmodellen gesetzt. Limitationen und Potentiale der einzelnen Teilprozesse werden dargelegt. Unter Anwendung der beschriebenen Strukturierungs- und Prozessparameter ist die Erstellung funktional einsetzbarer Prägewerkzeuge möglich. Für die Strukturübertragung konnte die Abformbarkeit der in die Oberflächen der Prägewerkzeuge eingebrachten beugungsoptisch wirksamen Gitterstrukturen mit Gitterperioden von kleiner gleich 2 µm bei Kontaktzeiten im Millisekundenbereich nachgewiesen werden

    Why Privacy-Preserving Protocols Are Sometimes Not Enough: A Case Study of the Brisbane Toll Collection Infrastructure

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    The use of Electronic Toll Collection (ETC) systems is on the rise, as these systems have a significant impact on reducing operational costs. Toll service providers (TSPs) access various information, including drivers’ IDs and monthly toll fees, to bill drivers. While this is legitimate, such information could be misused for other purposes violating drivers’ privacy, most prominent, to infer drivers’ movement patterns. To this end, privacy-preserving ETC (PPETC) schemes have been designed to minimize the amount of information leaked while still allowing drivers to be charged. We demonstrate that merely applying such PPETC schemes to current ETC infrastructures may not ensure privacy. This is due to the (inevitable) minimal information leakage, such as monthly toll fees, which can potentially result in a privacy breach when combined with additional background information, such as road maps and statistical data. To show this, we provide a counterexample using the case study of Brisbane’s ETC system. We present two attacks: the first, being a variant of the presence disclosure attack, tries to disclose the toll stations visited by a driver during a billing period as well as the frequency of visits. The second, being a stronger attack, aims to discover cycles of toll stations (e.g., the ones passed during a commute from home to work and back) and their frequencies. We evaluate the success rates of our attacks using real parameters and statistics from Brisbane’s ETC system. In one scenario, the success rate of our toll station disclosure attack can be as high as 94%. This scenario affects about 61% of drivers. In the same scenario, our cycle disclosure attack can achieve a success rate of 51%. It is remarkable that these high success rates can be achieved by only using minimal information as input, which is, e.g., available to a driver’s payment service provider or bank, and by following very simple attack strategies without exploiting optimizations. As a further contribution, we nalyze how the choice of various parameters, such as the set of toll rates, the number of toll stations, and the billing period length, impact a driver’s privacy level regarding our attacks

    Microstructuring of Steel and Hard Metal using Femtosecond Laser Pulses

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    AbstractNew results on three-dimensional micro-structuring of tungsten carbide hard metal and steel using femtosecond laser pulses will be presented. For the investigations, a largely automated high-precision fs-laser micromachining station was used. The fs-laser beam is focused onto the sample surface using different objectives. The investigations of the ablation behaviour of the various materials in dependence of the laser processing parameters will be presented. In the second part, complex 3D microstructures with a variety of geometries and resolutions down to a few micrometers will be presented. On of the Goal of these investigations was to create defined microstructures in tooling equipments such as cutting inserts

    Why Privacy-Preserving Protocols Are Sometimes Not Enough: A Case Study of the Brisbane Toll Collection Infrastructure

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    peer reviewedThe use of Electronic Toll Collection (ETC) systems is on the rise, as these systems have a significant impact on reducing operational costs. Toll service providers (TSPs) access various information, including drivers' IDs and monthly toll fees, to bill drivers. While this is legitimate, such information could be misused for other purposes violating drivers' privacy, most prominent, to infer drivers' movement patterns. To this end, privacy-preserving ETC (PPETC) schemes have been designed to minimize the amount of information leaked while still allowing drivers to be charged. We demonstrate that merely applying such PPETC schemes to current ETC infrastructures may not ensure privacy. This is due to the (inevitable) minimal information leakage, such as monthly toll fees, which can potentially result in a privacy breach when combined with additional background information, such as road maps and statistical data. To show this, we provide a counterexample using the case study of Brisbane's ETC system. We present two attacks: the first, being a variant of the presence disclosure attack, tries to disclose the toll stations visited by a driver during a billing period as well as the frequency of visits. The second, being a stronger attack, aims to discover cycles of toll stations (e.g., the ones passed during a commute from home to work and back) and their frequencies. We evaluate the success rates of our attacks using real parameters and statistics from Brisbane's ETC system. In one scenario, the success rate of our toll station disclosure attack can be as high as 94%. This scenario affects about 61% of drivers. In the same scenario, our cycle disclosure attack can achieve a success rate of 51%. It is remarkable that these high success rates can be achieved by only using minimal information as input, which is, e.g., available to a driver's payment service provider or bank, and by following very simple attack strategies without exploiting optimizations. As a further contribution, we analyze how the choice of various parameters, such as the set of toll rates, the number of toll stations, and the billing period length, impact a driver's privacy level regarding our attacks

    A Survey on Privacy-preserving Electronic Toll Collection Schemes for Intelligent Transportation Systems

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    As part of Intelligent Transportation Systems (ITS), Electronic toll collection (ETC) is a type of toll collection system (TCS) which is getting more and more popular as it can not only help to finance the government's road infrastructure but also it can play a crucial role in pollution reduction and congestion management. As most of the traditional ETC schemes (ETCS) require identifying their users, they enable location tracking. This violates user privacy and poses challenges regarding the compliance of such systems with privacy regulations such as the EU General Data Protection Regulation (GDPR). So far, several privacy-preserving ETC schemes have been proposed. To the best of our knowledge, this is the first survey that systematically reviews and compares various characteristics of these schemes, including components, technologies, security properties, privacy properties, and attacks on ETCS. This survey first categorizes the ETCS based on two technologies, GNSS and DSRC. Then under these categories, the schemes are classified based on whether they provide formal proof of security and support security analysis. We also demonstrate which schemes specifically are/are not resistant to collusion and physical attacks. Then, based on these classifications, several limitations and shortcomings in privacy-preserving ETCS are revealed. Finally, we identify several directions for future research

    A nice surprise? Predictive processing and the active pursuit of novelty

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    Recent work in cognitive and computational neuroscience depicts human brains as devices that minimize prediction error signals: signals that encode the difference between actual and expected sensory stimulations. This raises a series of puzzles whose common theme concerns a potential misfit between this bedrock informationtheoretic vision and familiar facts about the attractions of the unexpected. We humans often seem to actively seek out surprising events, deliberately harvesting novel and exciting streams of sensory stimulation. Conversely, we often experience some wellexpected sensations as unpleasant and to-be-avoided. In this paper, I explore several core and variant forms of this puzzle, using them to display multiple interacting elements that together deliver a satisfying solution. That solution requires us to go beyond the discussion of simple information-theoretic imperatives (such as 'minimize long-term prediction error') and to recognize the essential role of species-specific prestructuring, epistemic foraging, and cultural practices in shaping the restless, curious, novelty-seeking human mind

    Embryonic Morphogen Nodal Promotes Breast Cancer Growth and Progression

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    Breast cancers expressing human embryonic stem cell (hESC)-associated genes are more likely to progress than well-differentiated cancers and are thus associated with poor patient prognosis. Elevated proliferation and evasion of growth control are similarly associated with disease progression, and are classical hallmarks of cancer. In the current study we demonstrate that the hESC-associated factor Nodal promotes breast cancer growth. Specifically, we show that Nodal is elevated in aggressive MDA-MB-231, MDA-MB-468 and Hs578t human breast cancer cell lines, compared to poorly aggressive MCF-7 and T47D breast cancer cell lines. Nodal knockdown in aggressive breast cancer cells via shRNA reduces tumour incidence and significantly blunts tumour growth at primary sites. In vitro, using Trypan Blue exclusion assays, Western blot analysis of phosphorylated histone H3 and cleaved caspase-9, and real time RT-PCR analysis of BAX and BCL2 gene expression, we demonstrate that Nodal promotes expansion of breast cancer cells, likely via a combinatorial mechanism involving increased proliferation and decreased apopotosis. In an experimental model of metastasis using beta-glucuronidase (GUSB)-deficient NOD/SCID/mucopolysaccharidosis type VII (MPSVII) mice, we show that although Nodal is not required for the formation of small (\u3c100 cells) micrometastases at secondary sites, it supports an elevated proliferation:apoptosis ratio (Ki67:TUNEL) in micrometastatic lesions. Indeed, at longer time points (8 weeks), we determined that Nodal is necessary for the subsequent development of macrometastatic lesions. Our findings demonstrate that Nodal supports tumour growth at primary and secondary sites by increasing the ratio of proliferation:apoptosis in breast cancer cells. As Nodal expression is relatively limited to embryonic systems and cancer, this study establishes Nodal as a potential tumour-specific target for the treatment of breast cancer. © 2012 Quail et al

    Psychosocial factors associated with outcomes of sports injury rehabilitation in competitive athletes: a mixed studies systematic review.

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    The prime focus of research on sports injury has been on physical factors. This is despite our understanding that when an athlete sustains an injury it has psychosocial as well as physical impacts. Psychosocial factors have been suggested as prognostic influences on the outcomes of rehabilitation. The aim of this work was to address the question: are psychosocial factors associated with sports injury rehabilitation outcomes in competitive athletes?Mixed studies systematic review (PROSPERO reg.CRD42014008667).Electronic database and bibliographic searching was undertaken from the earliest entry until 1 June 2015. Studies that included injured competitive athletes, psychosocial factors and a sports injury rehabilitation outcome were reviewed by the authors. A quality appraisal of the studies was undertaken to establish the risk of reporting bias.25 studies were evaluated that included 942 injured competitive athletes were appraised and synthesised. Twenty studies had not been included in previous reviews. The mean methodological quality of the studies was 59% (moderate risk of reporting bias). Convergent thematic analysis uncovered three core themes across the studies: (1) emotion associated with rehabilitation outcomes; (2) cognitions associated with rehabilitation outcomes; and (3) behaviours associated with rehabilitation outcomes. Injury and performance-related fears, anxiety and confidence were associated with rehabilitation outcomes. There is gender-related, age-related and injury-related bias in the reviewed literature.Psychosocial factors were associated with a range of sports injury rehabilitation outcomes. Practitioners need to recognise that an injured athlete's thoughts, feelings and actions may influence the outcome of rehabilitation
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