1,722,252 research outputs found
Hough Transform Proposal and Simulations for Particle Track Recognition for LHC Phase-II Upgrade
Get PDFIn the near future, LHC experiments will continue future upgrades by overcoming the technological obsolescence of the detectors and the readout capabilities. Therefore, after the conclusion of a data collection period, CERN will have to face a long shutdown to improve overall performance, by updating the experiments, and implementing more advanced technologies and infrastructures. In particular, the largest LHC experiment, i.e., ATLAS, will upgrade parts of the detector, the trigger, and the data acquisition system. In addition, the ATLAS experiment will complete the implementation of new strategies, algorithms for data handling, and transmission to the final storage apparatus. This paper presents an overview of an upgrade planned for the second half of this decade for the ATLAS experiment. In particular, we show a study of a novel pattern recognition algorithm used in the trigger system, which is a device designed to provide the information needed to select physical events from unnecessary background data. The idea is to use a well known mathematical transform, the Hough transform, as the algorithm for the detection of particle trajectories. The effectiveness of the algorithm has already been validated in the past, regardless of particle physics applications, to recognize generic shapes within images. On the contrary, here, we first propose a software emulation tool, and a subsequent hardware implementation of the Hough transform, for particle physics applications. Until now, the Hough transform has never been implemented on electronics in particle physics experiments, and since a hardware implementation would provide benefits in terms of overall Latency, we complete the studies by comparing the simulated data with a physical system implemented on a Xilinx hardware accelerator (FELIX-II card). In more detail, we have implemented a low-abstraction RTL design of the Hough transform on Xilinx UltraScale+ FPGAs as target devices for filtering applications
[Free radicals in human pathology (editorial)]
No full textThe role of free radicals has been suggested in many different diseases; the molecular mechanisms of radical-induced damage have been widely investigated: the main effects on cellular components are lipid peroxidation, protein denaturation and DNA damage causing alteration in membrane functions, impaired enzyme activity and genetic alterations, including cancer. Since oxidative metabolism produces some radicals, aerobic organisms acquired a complex defensive system against radical attack, based on localization of oxidative reactions, enzymes that scavenge free radicals or their products and antioxidant vitamins. Diseases may arise from increased exposure to radicals or from impaired efficiency of protective systems. The role of oxygen radicals in cancerogenesis, alcoholic liver disease and the aging process is also briefly discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
I sartani nel trattamento delle malattie cardiovascolari: aspetti clinici e farmacoeconomici dell'impiego di candesartan.
No full textAspetti clinici di impiego del candesartan e rassegna della letteratura internazionale
Hough Transform FPGA solution for High Energy Physics online fast tracking
Get PDFIn the coming years, significant upgrades are planned for ATLAS and other High Energy
Physics experiments at CERN. Both the technologies and methodologies employed will undergo changes for the scheduled runs at the end of the decade. The LHC accelerator itself will also undergo multiple modifications, allowing it to achieve a peak of instantaneous luminosity up to 5–7.5 × 1034 cm−2 s−1. These enhancements will necessitate the experiments to handle a greater number of events at the conclusion of the data acquisition chain. For instance, ATLAS will be compelled to employ online tracking for its inner detector, aiming to achieve a final event rate of 10 kHz from the 1MHz originating from the Calorimeters and the Muon Spectrometer trigger discrimination.
Among the architectures explored to expedite fast tracking, there is consideration of a “hardware accelerator” farm, an infrastructure made of interconnected accelerators such as GPUs and FPGAs, designed to accelerate the tracking processes. The project presented here proposes a tuned Hough Transform algorithm implementation on high-end FPGA technology, specifically designed to adapt to various tracking situations. A development platform comprising software and firmware tools has been created to study different datasets. This platform utilizes software to simulate the firmware and to perform hardware tests. AMD-Xilinx FPGAs were chosen to implement and asses the system, with specific boards such as the VC709, the VCU1525 and the Alveo U250. Strategies such as low-level design for the firmware architecture, leveraging the card’s features like PCI Express data transfer, and the > 1 million gates array available have been exploited. The system underwent testing using internally simulated events generated within the ATLAS environment. Simulated 200 pile up events were used to evaluate the algorithm effectiveness. The average processing time was estimated to be below 5 μs, with the capability to concurrently process two events per algorithm instance. Internal efficiency tests have shown conditions where track finding performance for single muon tracking exceeded 95%
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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