![]() Schmidt, Thomas ![]() Scientific Conference (2015, March) Detailed reference viewed: 101 (0 UL)![]() Schmidt, Thomas ![]() Scientific Conference (2015, July) Detailed reference viewed: 114 (0 UL)![]() ; ; et al in Physical Review. B, Condensed Matter (2015), 91 Based on the Bardeen Cooper Schrieffer (BCS) theory of superconductivity, the coherent splitting of Cooper pairs from a superconductor to two spatially separated quantum dots has been predicted to ... [more ▼] Based on the Bardeen Cooper Schrieffer (BCS) theory of superconductivity, the coherent splitting of Cooper pairs from a superconductor to two spatially separated quantum dots has been predicted to generate nonlocal pairs of entangled electrons. In order to test this hypothesis, we propose a scheme to transfer the spin state of a split Cooper pair onto the polarization state of a pair of optical photons. We show that the produced photon pairs can be used to violate a Bell inequality, unambiguously demonstrating the entanglement of the split Cooper pairs. [less ▲] Detailed reference viewed: 128 (2 UL)![]() ; ; et al in Journal of Geophysical Research. Solid Earth (2013), 118 The accuracy of Global Positioning System (GPS) time series is degraded by the presence of offsets. If these are not detected and adjusted correctly they bias velocities, and hence geophysical estimates ... [more ▼] The accuracy of Global Positioning System (GPS) time series is degraded by the presence of offsets. If these are not detected and adjusted correctly they bias velocities, and hence geophysical estimates, and degrade the terrestrial reference frame. They also alter apparent time series noise characteristics as undetected offsets resemble a random walk process. As such, offsets are a substantial problem. A number of offset detection methods have been developed across a range of fields, and some of these are now being tested in geodetic time series. The DOGEx (Detection of Offsets in GPS Experiment) project aims to test the effectiveness of automated and manual offset detection approaches and the subsequent effect on GPS-derived velocities. To do this, simulated time series were first generated that mimicked realistic GPS data consisting of a velocity component, offsets, white and flicker noises (1/f spectrum noises) composed in an additive model. We focus on offset detection and together with velocity biases induced by incorrect offset detection. We show that, at present, manual methods (where offsets are hand -picked by GPS time series experts) almost always give better results than automated or semi-automated methods (two automated methods give quite similar velocity bias as the best manual solutions). For instance, the 5th percentile ranges (5% to 95%) in velocity bias for automated approaches is equal to 4.2mm/year,whereas it is equal to 1.8mm/yr for the manual solutions. However the True Positive detection rate of automated solutions is significantly higher than those for the manual solutions, being around 37% for the best automated, and 42% for the best manual solution. The amplitude of offsets detectable by automated solutions is greater than for hand picked solutions, with the smallest detectable offset for the two best manual solutions equal to 5mm and 7mm and to 8mm and 10mm for the two best automated solutions. The best manual solutions yielded velocity biases from the truth commonly in the range ±0.2mm/yr, whereas the best automated solutions produced biases no better than double this range. Assuming the simulated time series noise levels continue to be representative of real GPS time series, robust geophysical interpretation of individual site velocities lower than these levels is therefore not robust. Further work is required before we can routinely interpret sub-mm/yr velocities for single GPS stations. [less ▲] Detailed reference viewed: 210 (6 UL)![]() Li, Li ![]() ![]() ![]() Scientific Conference (2014, February 26) The number of Android apps have grown explosively in recent years and the number of apps leaking private data have also grown. It is necessary to make sure all the apps are not leaking private data before ... [more ▼] The number of Android apps have grown explosively in recent years and the number of apps leaking private data have also grown. It is necessary to make sure all the apps are not leaking private data before putting them to the app markets and thereby a privacy leaks detection tool is needed. We propose a static taint analysis approach which leverages the control-flow graph (CFG) of apps to detect privacy leaks among Android apps. We tackle three problems related to inter- component communication (ICC), lifecycle of components and callback mechanism making the CFG imprecision. To bridge this gap, we ex- plicitly connect the discontinuities of the CFG to provide a precise CFG. Based on the precise CFG, we aim at providing a taint analysis approach to detect intra-component privacy leaks, inter-component privacy leaks and also inter-app privacy leaks. [less ▲] Detailed reference viewed: 540 (32 UL)![]() ![]() Chauvel, Louis ![]() ![]() Scientific Conference (2018, June 09) Background. Mortality-by-cause analyses as done in the Global Burden of Disease 2016 update are helpful to monitor progress of public health improvements within and across countries. However, separate ... [more ▼] Background. Mortality-by-cause analyses as done in the Global Burden of Disease 2016 update are helpful to monitor progress of public health improvements within and across countries. However, separate analyses by cause and country miss larger patterns of public health crises that are restricted to certain cohorts and periods. Those public health crises may go unnoticed even if they affect several countries and thus come with some threat potential. We propose a new method to detect cohorts with increased mortality at certain ages and periods. Method. We develop an analytical and visualizing technique based on established Age-Period-Cohort-Detrended (APCD) methodology (Chauvel and Schröder 2014). After detecting all-cause mortality increases, plotting the resulting age-period coefficients and APCD residuals in equilateral Lexis diagrams, mortality patterns can be distinguished as age, period, or cohort trends and fluctuations. Age-period interactions are plotted as ‘big red spots’. We employ the new technique in data from the Human Mortality Database, spanning 25-60 years of age, calendar years 1975-2010, and 25 countries. Results. We detect age-period interactions of young-adult cohorts in the early 1990s in Spain, other southern European countries and the U.S. Additional analyses with WHO mortality data show that mortality increases are mostly due to increased HIV/AIDS mortality. Discussion. Country-specific explanations, such as political frustrations in Spain, have been proposed to explain the 1990s increases in HIV/AIDS mortality. However, the new technique suggests that increases in HIV/AIDS mortality were more likely to be due to specific behaviors of cohorts of certain ages in a certain period. We discuss limitations of the method, such as detecting social class mortality differences of affected cohorts. Altogether, the new technique offers intuitive and efficient handling of large amounts of age-country-year mortality information. The method can further be applied in the fields of education, longevity, and demography at large. [less ▲] Detailed reference viewed: 130 (4 UL)![]() Hommes, Stefan ![]() ![]() ![]() in IFIP Networking 2012 (2012) In this paper we describe a practical approach for detecting a class of backdoor communication channel that relies on port knocking in order to activate a backdoor on a remote compromised system ... [more ▼] In this paper we describe a practical approach for detecting a class of backdoor communication channel that relies on port knocking in order to activate a backdoor on a remote compromised system. Detecting such activation sequences is extremely challenging because of varying port sequences and easily modifiable port values. Simple signature-based ap- proaches are not appropriate, whilst more advanced statistics-based test- ing will not work because of missing and incomplete data. We leverage techniques derived from the data mining community designed to detect se- quences of rare events. Simply stated, a sequence of rare events is the joint occurrence of several events, each of which is rare. We show that search- ing for port knocking sequences can be reduced to a problem of finding rare associations. We have implemented a prototype and show some ex- perimental results on its performance and underlying functioning. [less ▲] Detailed reference viewed: 231 (7 UL)![]() ; ; Teferle, Felix Norman ![]() in Geophysical Journal International (2012), 191(2), 569-578 A large storm surge event occurred on 2007 November 2009 in the southern North Sea where strong winds caused the sea level to rise drastically by up to 3 m within several hours. Based on the Proudman ... [more ▼] A large storm surge event occurred on 2007 November 2009 in the southern North Sea where strong winds caused the sea level to rise drastically by up to 3 m within several hours. Based on the Proudman Oceanographic Laboratory storm surge model, the predicted loading displacements at coastal stations can reach a few centimetres in the vertical and several millimetres in the horizontal directions. In this study, we used two-hourly global positioning system (GPS) positions at 26 stations around the southern North Sea to identify the loading displacements caused by this storm surge event. We find that the mean rms of the differences between the estimated and predicted displacements are 4.9, 1.3 and 1.4 mm, which are insignificant compared to the one-sigma GPS positioning errors of 5.1, 2.0 and 2.4 mm for the Up, East and North components, respectively. More interestingly, in both vertical and horizontal directions, the estimated displacements successfully tracked the temporal evolution of the storm surge loading effects. In addition, within the whole of 2007 November, we used the predicted displacements to correct the two-hourly GPS positions, and consequently reduced the rms of the estimated displacements on average from 9.3, 3.0 and 2.9 mm to 7.8, 2.8 and 2.8 mm for Up, East and North components, respectively. Therefore, subdaily loading effects due to storm surges should be paid attention to in the GPS positioning that contributes to crustal-motion studies around shallow seas such as the North Sea, the Baltic Sea and the Gulf of Mexico. [less ▲] Detailed reference viewed: 188 (1 UL)![]() ; Brust, Matthias R. ![]() in Advances in Intelligent Systems and Computing (2018) Detailed reference viewed: 167 (2 UL)![]() Chauvel, Louis ![]() ![]() in PAA Server (2017, April 28) In times of wide availability of yearly mortality information of age and period groups all over the world, we lack in tools that detect and graph fine-grained deviations from mortality trends. We provide ... [more ▼] In times of wide availability of yearly mortality information of age and period groups all over the world, we lack in tools that detect and graph fine-grained deviations from mortality trends. We provide a new age-period-cohort based methodology, combining information from age-period (AP) and APC-Detrended (APCD) analyses to detect all-cause mortality increases. Plotting the resulting AP coefficients and APCD residuals in equilateral Lexis diagrams, mortality patterns can easily be distinguished as age, period, or cohort trends and fluctuations. Additionally, we detect abnormalities as interactions of age and period (‘big red spots’). We then investigate the ‘red spots’ of mortality of young-adult cohorts in the early 1990s in Spain, other southern European countries and the U.S. to delineate their simultaneously occurring public health crises. Additional analyses with WHO mortality data show that mortality increases are mostly due to increased HIV/AIDS mortality. We discuss possible applications of the new method. [less ▲] Detailed reference viewed: 255 (13 UL)![]() ![]() Chauvel, Louis ![]() ![]() in Bell, Andrew (Ed.) Age, Period, and Cohort Effects (2021) In a time of worldwide availability of annual age-specific mortality data, we lack basic tools for detecting and graphing, from a comparative perspective, fine-grained deviations from mortality trends. We ... [more ▼] In a time of worldwide availability of annual age-specific mortality data, we lack basic tools for detecting and graphing, from a comparative perspective, fine-grained deviations from mortality trends. We provide a new age-period-cohort-based methodology, combining information from age-period (AP) and APC-Detrended (APCD) analyses to detect all-cause mortality increases. Plotting the resulting AP coefficients and APCD residuals in equilateral Lexis diagrams, mortality patterns can easily be distinguished as age, period, or cohort trends and fluctuations. We highlight abnormalities as interactions of age and period (‘Black Holes’). We then investigate the ‘Black Holes’ of mortality of young-adult cohorts in the early 1990s in Spain, other southern European countries, and the U.S., in emphasizing their simultaneously occurring mortality crises. Additional analyses with WHO mortality data and epidemiological evidence from other studies show that these mortality increases likely result from lack of treatment and inadequate public health responses to the beginnings of the HIV/AIDS epidemic. We discuss other possible applications of the new method. [less ▲] Detailed reference viewed: 271 (24 UL)![]() Kintis, Marinos ![]() ![]() in IEEE Transactions on Software Engineering (2017) Detailed reference viewed: 235 (8 UL)![]() Wagener, Gerard ![]() Scientific Conference (2008) Detailed reference viewed: 60 (0 UL)![]() Djemour, Rabie ![]() ![]() ![]() in Applied Physics Letters (2013), 102 Detailed reference viewed: 242 (14 UL)![]() Liga, Davide ![]() in International Joint Conference on Rules and Reasoning (2019) The aim of this study is to propose an innovative methodology to classify argumentative stances in a monologic argumentative context. Particularly, the proposed approach shows that Tree Kernels can be ... [more ▼] The aim of this study is to propose an innovative methodology to classify argumentative stances in a monologic argumentative context. Particularly, the proposed approach shows that Tree Kernels can be used in combination with traditional textual vectorization to discriminate between different stances of opposition without the need of extracting highly engineered features. This can be useful in many Argument Mining sub-tasks. In particular, this work explores the possibility of classifying opposition stances by training multiple classifiers to reach different degrees of granularity. Noticeably, discriminating support and opposition stances can be particularly useful when trying to detect Argument Schemes, one of the most challenging sub-task in the Argument Mining pipeline. In this sense, the approach can be also considered as an attempt to classify stances of opposition that are related to specific Argument Schemes. [less ▲] Detailed reference viewed: 27 (1 UL)![]() ; Mohamed Ali, Mohamed Adel ![]() ![]() in European Conference on Space Debris (2021), 8(1), Detailed reference viewed: 127 (14 UL)![]() Trefois, Christophe ![]() Doctoral thesis (2014) Critical transitions exist in many dynamical systems, ranging from the Earth’s cli- mate system to microcosm populations. During a critical transition, the state of a dynamical system abruptly changes ... [more ▼] Critical transitions exist in many dynamical systems, ranging from the Earth’s cli- mate system to microcosm populations. During a critical transition, the state of a dynamical system abruptly changes from one stable state to another, typically without obvious prior warning. Preventing such abrupt changes remains a chal- lenge, however recently, several metrics were suggested as early warning signals. These indicators are thought to have predictive value for upcoming critical transi- tions. In Parkinson’s disease, there are no detectable motor symptoms in a patient until neuronal dopaminergic cell death exceeds 60–70%. Being able to define early warning signals in a disease context could open new avenues for both preventive and disease modifying treatments. We hypothesize that the dynamics of progression of some disorders including Parkinson’s disease could be manifested by critical tran- sitions. However, before rushing into medical applications, a thorough framework needs to be developed that aims to describe such nonlinear dynamics in cellular systems. In this thesis, we set out to study critical transitions in a simple cellular model using mitochondrial membrane potential ∆Ψ m as readout. To identify criti- cal transitions, we established a modular high-content screening platform allowing systematic perturbation of oxidative phosphorylation. To increase the probability for detecting a critical transition in ∆Ψ m , five inhibitory compounds were combined in multiple pairwise concentration landscapes. We show that critical transitions, de- tectable via ∆Ψ m , are an intrinsic property of the cellular system studied and that two-component Gaussian mixture models adequately capture the dynamics of the critical transition occurring for the combination of Oligomycin A and Antimycin A. Adding to that, we identified the coefficient of variation as a strong early warning signal for the upcoming of the critical transitions. This thesis should serve as a foundation for a broader application of critical transitions and early warning sig- nals in both cell culture systems and translational studies aiming to understand the nonlinear dynamics of biological systems. [less ▲] Detailed reference viewed: 184 (36 UL)![]() ![]() ; Ottersten, Björn ![]() in IEEE Transactions on Signal Processing (1991), SP-39(11), 24362449 Detailed reference viewed: 58 (0 UL)![]() Nguyen, Viet Ha ![]() ![]() in Carrera, E.; Miglioretti, F; Petrolo, M. (Eds.) 6th ECCOMAS Thematic Conference on Smart Structures and Materials (SMART2013), Torino 24-26 June 2013 (2013, June) The objective of this work is to address the problem of damage detection in civil engineering structures using non-destructive techniques and dynamic measurements. To this purpose, time- or frequency ... [more ▼] The objective of this work is to address the problem of damage detection in civil engineering structures using non-destructive techniques and dynamic measurements. To this purpose, time- or frequency-domain methods are used for the diagnostics. It consists in practical output-only techniques as Stochastic Subspace Identification (SSI) for modal identification or Enhanced Principal Component Analysis (EPCA) for detecting the presence of damage. The use of the Hankel matrix instead of the observation matrix improves effectively the robustness of these methods. Damage localization is based on Frequency Response Functions (FRFs) and sensitivity analysis of PCA results. The efficiency of the above-mentioned methods has been demonstrated in earlier studies mainly on numerical examples and small-scale laboratory experiments. It was also tested successfully on industrial examples to perform machine condition monitoring using a reduced set of sensors. In this work, the investigation is performed on precast prestressed and non-prestressed concrete slabs. Successive damages were artificially introduced in the slabs by loading heavy weights and by cutting steel wires, which induced cracks in the structure. The examples show the consequences of the considered techniques for damage identification. The results that are very different between prestressed and non-prestressed slabs may be used as input for the condition control of this kind of structures. [less ▲] Detailed reference viewed: 106 (18 UL)![]() Bungard, Volker ![]() ![]() ![]() in CD-Proceedings, Paper ID: 358 (2011) Detailed reference viewed: 121 (29 UL) |
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