1,721,247 research outputs found
On-board Satellite Image Compression using Reconfigurable FPGAs
No full textRemote sensing satellites operate almost exclusively in a store-and-forward mode, with acquired imagery stored on board until being downlinked when ground stations come within view. Space-borne imaging sensors generate tremendous volumes of data at very high rates, however storage capacity and communication bandwidth are expensive satellite resources. By compressing the images as they are acquired, better use is made of available storage and bandwidth capacity. Reconfigurable computing technology, which combines the flexibility of traditional microprocessors with the performance of ASIC devices, is very promising for space applications. The High Performance Computing (HPC-I) payload, based on a radiation hardened reconfigurable FPGA has been developed and integrated into the Australian scientific mission satellite FedSat. HPC-I is a testbed in space to validate reconfigurable logic for a variety of satellite applications. The design and implementation on HPC-I of the On-Board Image Compression System (OBICS) is presented, and its compression performance evaluated using JPEG standard as a benchmark. The results indicate that FPGAs and HPC-I are suitable platforms for such systems, and that satisfactory compression can only be achieved with moderately complex logic designs
FPGA Based Real-time Adaptive Filtering for Space Applications
No full textSatellites and other space-based signal processing systems face a challenging operating environment. In addition to radiation related effects, the satellites themselves are often electrically noisy, resulting in high levels of noise and interference in data signals. Digital signal processing systems such as adaptive filters are vital components for the next generation of satellites. Most current satellite systems have limited computing resources for on-board digital signal processing and lack flexibility to adapt to changing operation requirements. The deployment of reconfigurable field programmable gate array (FPGA) technology on-board satellites is a very promising solution for digital signal processing in space, as they offer flexibility, scalability and high performance. The high performance computing (HPC-I) payload integrated into the Australian scientific mission satellite FedSat is designed to evaluate the deployment of FPGA technology for a variety of space applications. This paper elaborates on implementing rule-based adaptive filtering techniques on FPGAs for space applications, presenting the design and implementation of an adaptive finite impulse response (FIR) filter on HPC-I. A fuzzy adaptive image filtering algorithm for remote sensing applications is also considered
FPGA-Based Cloud Detection for Real-time Onboard Remote Sensing
No full textReconfigurable computing is an enabling technology for real-time image processing onboard remote sensing satellites. This can potentially reduce the delay between image capture, analysis and action, and also reduce onboard storage and downlink capacity requirements. This paper discusses the design and implementation of a real-time cloud detection system intended for use within an onboard remote sensing platform. The High Performance Computing (HPC-1) payload, designed and developed for the Australian scientific satellite FedSat, is briefly introduced as a demonstration of onboard processing in space using reconfigurable logic. A high level conceptual design of the proposed remote sensing system is provided, before details of the cloud detection design and implementation are presented. Results from simulation and testing demonstrate very promising performance in terms of data throughput and detection capabilities
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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