1,420 research outputs found
Content-Based Video Retrieval in Historical Collections of the German Broadcasting Archive
The German Broadcasting Archive (DRA) maintains the cultural heritage of
radio and television broadcasts of the former German Democratic Republic (GDR).
The uniqueness and importance of the video material stimulates a large
scientific interest in the video content. In this paper, we present an
automatic video analysis and retrieval system for searching in historical
collections of GDR television recordings. It consists of video analysis
algorithms for shot boundary detection, concept classification, person
recognition, text recognition and similarity search. The performance of the
system is evaluated from a technical and an archival perspective on 2,500 hours
of GDR television recordings.Comment: TPDL 2016, Hannover, Germany. Final version is available at Springer
via DO
Transition to turbulence in particulate pipe flow
We investigate experimentally the influence of suspended particles on the
transition to turbulence. The particles are monodisperse and neutrally-buoyant
with the liquid. The role of the particles on the transition depends both upon
the pipe to particle diameter ratios and the concentration. For large
pipe-to-particle diameter ratios the transition is delayed while it is lowered
for small ratios. A scaling is proposed to collapse the departure from the
critical Reynolds number for pure fluid as a function of concentration into a
single master curve.Comment: 4 pages, 4 figure
Diffractive deeply inelastic scattering in future electron-ion colliders
The impact of nonlinear effects in the diffractive observables that will be
measured in future electron-ion collisions is investigated. We present, for the
first time, the predictions for the diffractive structure function and reduced
cross sections derived using the solution to the Balitsky--Kovchegov equation
with the collinearly-improved kernel and including the impact-parameter
dependence. We demonstrate that the contribution of the diffractive events is
enhanced in nuclear collisions and that the study of the ratio between the
nuclear and proton predictions will be useful to discriminate among different
models of the dipole-target scattering amplitude and, consequently, will allow
us to constrain the description of QCD dynamics in parton densities.Comment: 12 pages, 10 figure
Asymptomatic Carotid Stenosis and Cognitive Improvement using Transcervical Stenting with Protective Flow Reversal Technique
ObjectivesThe relationship between carotid artery stenosis and cognitive function in individuals without a history of stroke is not clear. The possible pathomechanisms of cognitive impairment include silent embolization and hypoperfusion. In this study the aim was to assess cognitive changes after transcervical carotid artery stenting with proximal cerebral protection by flow reversal in patients with asymptomatic carotid stenosis, a novel technique that has been proved to decrease the number intraoperative emboli.Methods25 consecutive patients were assessed, of which 22 were men (88%) mean age of 74 years with severe asymptomatic carotid stenosis who underwent revascularization by carotid artery stenting (CAS) with flow reversal. Patients were evaluated 1 day before and 6 months after the procedure using a standardized neuropsychological battery. Test scores were adjusted according to age, sex, education level and were standardized (0–100). The mean of all the cognitive function scores yielded the global cognitive score (GCS).ResultsThere were no neurological complications during the procedure or during hospitalization in any patient. No deaths or cardiac complications occurred in any patient. The pre-procedure neuropsychological study showed cognitive impairment in: information processing speed in 15 patients (62.5%), visuospatial function in 14 (56.0%), memory in 18 (72.0%), executive functions in 14 (56.0%), language in three (12.0%), attention in 10 (40.0%), and global cognitive performance in eight (32.0%). Comparison of these scores with those obtained 6-month post-procedure showed significant improvement in GCS in all patients (p = .002), with a particularly marked gain in information processing speed (p = .018). Although significant improvement was not found for the remaining cognitive functions assessed, some gain was documented, and there was no deterioration.ConclusionsRevascularization by transcervical CAS with flow reversal for cerebral protection results in improved neurocognitive performance in asymptomatic elderly patients with severe carotid artery stenosis
Proposal of novel single-phase power quality indicators considering subsynchronous frequency perturbations in voltage and current under non-sinusoidal conditions
This work pretends to reconsider power quality (PQ), in AC single-phase low voltage systems, considering perturbation sources with frequency components below the fundamental frequency in voltage and current signals. These perturbations induced by sources like Geomagnetic Induced Currents (GMC), Arc Furnaces, switching VSC, etc. [1]-[2],[30]-[32], can occur in a frequency range comprised between DC and the fundamental frequency of the system. Standard PQ indexes do not characterize properly these subsynchronous frequency perturbations (SFFP), [2]-[3] and this work pretends to analyze the spectra from 0 to 50Hz for voltage and current, proposing new formulation for some PQ as a function of SSFP, with the intention of explaining the observed degradation of the power quality in single-phase low voltage electric systems.Peer ReviewedPostprint (published version
Offset-compensated comparator with full-input range in 150nm FDSOI CMOS-3d technology
Trabajo presentado al LASCAS celebrado en Iguazu (Brasil) del 24 al 26 de febrero de 2010.This paper addresses an offset-compensated comparator with full-input range in the 150nm FDSOI CMOS-3D technology from MIT- Lincoln Laboratory. The comparator discussed here makes part of a vision system. Its architecture is that of a self-biased inverter with dynamic offset correction. At simulation level, the comparator can reach a resolution of 0.1mV in an area of approximately 220μm2 with a time response of less than 40ns and a static power dissipation of 1.125μW.Peer Reviewe
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