1,260 research outputs found

    Smart Camera for MPEG-7

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    While a first generation of video coding techniques proposed to remove the redundancies in and between image frames to get smaller bitstreams, second generation schemes like MPEG-4 and MPEG-7 aim at doing content-based coding and interactivity. To reach this goal, tools for the extraction and description of semantic objects need to be developed. In this work, we propose an algorithm for the extraction and tracking of semantic objects and an MPEG-7 compliant descriptor set for generic objects; together, they can be seen like a smart camera for automatic scene description. Some parts of the proposed system will be tested by software. The tracking algorithm has been laid out so as to follow generic objects in scenes including partial occlusions and merging. To do this, we first localize each moving object of the scene using a change-detection mask. Then, a certain number of representative points called centroids is given to the objects by a fuzzy C-means algorithm. For each centroid of some current frame, we try to find the closest centroid in the previous frame. Once we found these pairs, each object can be labelled according to its corresponding previous centroids. The description structure is a subset of the DDL language used in MPEG-7. The main concern was to find a simple, but flexible descriptor set for generic objects. A corresponding C-structure for software implementations is also proposed and partially tested

    Characterization of the TruSense S310 Laser Range System for Contact-less Measurement of Liquid Levels in Large-Volume Neutrino Detectors

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    Neutrino experiments often use large volumes of water, organic scintillators or noble liquids as active detection material. Due to the large hydrostatic and buoyancy forces involved, precise knowledge of the liquid levels inside the detector tank are mandatory. Here we present the main characteristics of the TruSense S310 Laser Range System. Level measurements can be performed without direct contact to the liquid and through a gas-proof acrylic window, thus preserving the strict radiopurity and chemical requirements of the target liquid. We report the results of a suit of laboratory experiments for short-term precision tests (±\pm5\,mm) and long-term stability studies. Moreover, we demonstrate that the infrared laser can be used while standard bi-alkali PMTs are operational. We discuss the mechanical layout and integration of the system in the OSIRIS pre-detector that will monitor the radiopurity of the liquid scintillator for the large-volume neutrino experiment JUNO

    Surveillance Video for Mobile Devices

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    In this paper, we present a video encoding scheme that uses object-based adaptation to deliver surveillance video to mobile devices. The method relies on a set of complementary video adaptation strategies and generates content that matches various appliance and network resources. Prior to encoding, some of the adaptation strategies exploit video object segmentation and selective filtering in order to improve the perceived quality. Moreover, object segmentation enables the generation of automatic summaries and of simplified versions of the monitored scene. The performance of individual adaptation strategies is assessed using an objective video quality metric, which is also used to select the strategy that provides maximum value for the user under a given set of constraints. We demonstrate the effectiveness of the scheme on standard surveillance test sequences and realistic mobile client resource profiles

    Design and Implementation of a Universal Multimedia Access Environment

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    The objective of Universal Multimedia Access (UMA) is to permit any user equipped with whatever device the access to multimedia information. To handle the problems of UMA, two different approaches are commonly used: store variations of the same content and send the most appropriate one, and store the original content and adapt it on-the-fly. In this project a UMA environment using a mixture of both approaches is proposed. The tools allowing to reach this goal are: an Annotation Tool which describes media using MPEG-7, and a Client-Server Application that takes all the steps for the browsing and retrieval of media. After an overview of the designed UMA system, the function of the MPEG-7 annotation tool is explained. In particular, a descriptor list for content annotation is proposed. These descriptors are meant for content as well as for media feature description. The client-server application is then explained. Particular insight is given into the handling of user preferences and device capabilities. Finally, the UMA environment is tested on a Personal Computer simulating diverse devices and users. These tests show that the system behaves as expected and that possible extensions and improvements can be added

    Human copper transporter Ctr1 is functional in Drosophila, revealing a high degree of conservation between mammals and insects

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    Living cells have to carefully control the intracellular concentration of trace metals, especially of copper, which is at the same time essential but owing to its redox activity can also facilitate generation of reactive oxygen species. Mammals have two related copper transporters, Ctr1 and Ctr2, with Ctr1 playing the major role. The fruit fly Drosophila has three family members, termed Ctr1A, Ctr1B, and Ctr1C. Ctr1A is expressed throughout development, and a null mutation causes lethality at an early stage. Ctr1B ensures efficient copper uptake in the intestinal tract, whereas Ctr1C is mainly expressed in male gonads. Ectopic expression of Ctr1 transporters in Drosophila causes toxic effects due to excessive copper uptake. Here, we compare the effects of human Ctr1 (hCtr1) with those of the Drosophila homologs Ctr1A and Ctr1B in two overexpression assays. Whereas the overexpression of Drosophila Ctr1A and Ctr1B results in strong phenotypes, expression of hCtr1 causes only a very mild phenotype, indicating a low copper-import efficiency in the Drosophila system. However, this can be boosted by coexpressing the human copper chaperone CCS. Surprisingly, hCtr1 complements a lethal Ctr1A mutation at least as well as Ctr1A and Ctr1B transgenes. These findings reveal a high level of conservation between the mammalian and insect Ctr1-type copper importers, and they also demonstrate that the Drosophila Ctr1 proteins are functionally interchangeable

    Structural evolution in the neutron-rich nuclei 106Zr and 108Zr

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    The low-lying states in 106Zr and 108Zr have been investigated by means of {\beta}-{\gamma} and isomer spectroscopy at the RI beam factory, respectively. A new isomer with a half-life of 620\pm150 ns has been identified in 108Zr. For the sequence of even-even Zr isotopes, the excitation energies of the first 2+ states reach a minimum at N = 64 and gradually increase as the neutron number increases up to N = 68, suggesting a deformed sub-shell closure at N = 64. The deformed ground state of 108Zr indicates that a spherical sub-shell gap predicted at N = 70 is not large enough to change the ground state of 108Zr to the spherical shape. The possibility of a tetrahedral shape isomer in 108Zr is also discussed.Comment: 10 pages, 3 figures, Accepted for publication in Phys. Rev. Let

    Impact of hip arthroplasty registers on orthopaedic practice and perspectives for the future

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    Total hip arthroplasty (THA) registers are established in several countries to collect data aiming to improve the results after THA. Monitoring of adverse outcomes after THA has focused mainly on revision surgery, but patient-reported outcomes have also been investigated.Several surgery-related factors influencing the survival of the THA have been thoroughly investigated and have changed clinical practice. These factors include surgical approach, specific implants, the size of the components, type of fixation and different bone cements.Register data have been used to examine the risk of venous thromboembolism and bleeding after THA. These investigations have resulted in shorter duration of thromboprophylaxis and a reduced frequency of blood transfusion.Registers may provide specific information to surgeons on the outcome of all THAs that they have performed with a detailed analysis of revisions rates and reasons for the revisions.A number of other stakeholders can use register data to provide benchmarks. The National Joint Registry for England, Wales, Northern Ireland and the Isle of Man supplies data to the Orthopaedic Device Evaluation Panel (ODEP), which provides benchmarks at 3, 5, 7, 10, and 13 years graded from A*, A, B and C.Future perspectives: National registers have to play a major role in documenting the quality of THA in order to describe best practice and report implant outliers. The registers have to be used for research and post-market surveillance and register data may be a source for intelligent decision tools

    Influence of IFNL3/4 polymorphisms on the incidence of cytomegalovirus infection after solid-organ transplantation

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    Background. Polymorphisms in the interferon-λ (IFNL) 3/4 region have been associated with reduced hepatitis C virus clearance. We explored the role of such polymorphisms on the incidence of CMV infection in solid-organ transplant (SOT) recipients. Methods. Caucasian patients participating in the Swiss Transplant Cohort Study in 2008-2011 were included. A novel functional TT/-G polymorphism (rs368234815) in the CpG region upstream of IFNL3 was investigated. Results. A total of 840 SOT recipients at risk for CMV were included, among whom 373 (44%) received antiviral prophylaxis. The 12-months cumulative incidence of CMV replication and disease were 0.44 and 0.08, respectively. Patient homozygous for the minor rs368234815 allele (-G/-G) tended to have a higher cumulative incidence of CMV replication (SHR=1.30 [95%CI 0.97-1.74], P=0.07) compared to other patients (TT/TT or TT/-G). The association was significant among patients followed by a preemptive approach (SHR=1.46 [1.01-2.12], P=0.047), especially in patients receiving an organ from a seropositive donor (D+, SHR=1.92 [95%CI 1.30-2.85], P=0.001), but not among those who received antiviral prophylaxis (SHR=1.13 [95%CI 0.70-1.83], P=0.6). These associations remained significant in multivariate competing risk regression models. Conclusions. Polymorphisms in the IFNL3/4 region influence susceptibility to CMV replication in SOT recipients, particularly in patients not receiving antiviral prophylaxi

    IL1B and DEFB1 Polymorphisms Increase Susceptibility to Invasive Mold Infection After Solid-Organ Transplantation

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    Background. Single-nucleotide polymorphisms (SNPs) in immune genes have been associated with susceptibility to invasive mold infection (IMI) among hematopoietic stem cell but not solid-organ transplant (SOT) recipients. Methods. Twenty-four SNPs from systematically selected genes were genotyped among 1101 SOT recipients (715 kidney transplant recipients, 190 liver transplant recipients, 102 lung transplant recipients, 79 heart transplant recipients, and 15 recipients of other transplants) from the Swiss Transplant Cohort Study. Association between SNPs and the end point were assessed by log-rank test and Cox regression models. Cytokine production upon Aspergillus stimulation was measured by enzyme-linked immunosorbent assay in peripheral blood mononuclear cells (PBMCs) from healthy volunteers and correlated with relevant genotypes. Results. Mold colonization (n = 45) and proven/probable IMI (n = 26) were associated with polymorphisms in the genes encoding interleukin 1ÎČ (IL1B; rs16944; recessive mode, P = .001 for colonization and P = .00005 for IMI, by the log-rank test), interleukin 1 receptor antagonist (IL1RN; rs419598; P = .01 and P = .02, respectively), and ÎČ-defensin 1 (DEFB1; rs1800972; P = .001 and P = .0002, respectively). The associations with IL1B and DEFB1 remained significant in a multivariate regression model (P = .002 for IL1B rs16944; P = .01 for DEFB1 rs1800972). The presence of 2 copies of the rare allele of rs16944 or rs419598 was associated with reduced Aspergillus-induced interleukin 1ÎČ and tumor necrosis factor α secretion by PBMCs. Conclusions. Functional polymorphisms in IL1B and DEFB1 influence susceptibility to mold infection in SOT recipients. This observation may contribute to individual risk stratificatio

    The Fast Read-out System for the MAPMTs of COMPASS RICH-1

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    A fast readout system for the upgrade of the COMPASS RICH detector has been developed and successfully used for data taking in 2006 and 2007. The new readout system for the multi-anode PMTs in the central part of the photon detector of the RICH is based on the high-sensitivity MAD4 preamplifier-discriminator and the dead-time free F1-TDC chip characterized by high-resolution. The readout electronics has been designed taking into account the high photon flux in the central part of the detector and the requirement to run at high trigger rates of up to 100 kHz with negligible dead-time. The system is designed as a very compact setup and is mounted directly behind the multi-anode photomultipliers. The data are digitized on the frontend boards and transferred via optical links to the readout system. The read-out electronics system is described in detail together with its measured performances.Comment: Proceeding of RICH2007 Conference, Trieste, Oct. 2007. v2: minor change
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