1,720,976 research outputs found
Enhancing Real-time Embedded Image Processing Robustness on Reconfigurable Devices for Critical Applications
Full text linkNowadays, image processing is increasingly used in several application fields, such as biomedical, aerospace, or automotive. Within these fields, image processing is used to serve both non-critical and critical tasks. As example, in automotive, cameras are becoming key sensors in increasing car safety, driving assistance and driving comfort. They have been employed for infotainment (non-critical), as well as for some driver assistance tasks (critical), such as Forward Collision Avoidance, Intelligent Speed Control, or Pedestrian Detection. The complexity of these algorithms brings a challenge in real-time image processing systems, requiring high computing capacity, usually not available in processors for embedded systems. Hardware acceleration is therefore crucial, and devices such as Field Programmable Gate Arrays (FPGAs) best fit the growing demand of computational capabilities. These devices can assist embedded processors by significantly speeding-up computationally intensive software algorithms. Moreover, critical applications introduce strict requirements not only from the real-time constraints, but also from the device reliability and algorithm robustness points of view. Technology scaling is highlighting reliability problems related to aging phenomena, and to the increasing sensitivity of digital devices to external radiation events that can cause transient or even permanent faults. These faults can lead to wrong information processed or, in the worst case, to a dangerous system failure. In this context, the reconfigurable nature of FPGA devices can be exploited to increase the system reliability and robustness by leveraging Dynamic Partial Reconfiguration features. The research work presented in this thesis focuses on the development of techniques for implementing efficient and robust real-time embedded image processing hardware accelerators and systems for mission-critical applications. Three main challenges have been faced and will be discussed, along with proposed solutions, throughout the thesis: (i) achieving real-time performances, (ii) enhancing algorithm robustness, and (iii) increasing overall system's dependability. In order to ensure real-time performances, efficient FPGA-based hardware accelerators implementing selected image processing algorithms have been developed. Functionalities offered by the target technology, and algorithm's characteristics have been constantly taken into account while designing such accelerators, in order to efficiently tailor algorithm's operations to available hardware resources. On the other hand, the key idea for increasing image processing algorithms' robustness is to introduce self-adaptivity features at algorithm level, in order to maintain constant, or improve, the quality of results for a wide range of input conditions, that are not always fully predictable at design-time (e.g., noise level variations). This has been accomplished by measuring at run-time some characteristics of the input images, and then tuning the algorithm parameters based on such estimations. Dynamic reconfiguration features of modern reconfigurable FPGA have been extensively exploited in order to integrate run-time adaptivity into the designed hardware accelerators. Tools and methodologies have been also developed in order to increase the overall system dependability during reconfiguration processes, thus providing safe run-time adaptation mechanisms. In addition, taking into account the target technology and the environments in which the developed hardware accelerators and systems may be employed, dependability issues have been analyzed, leading to the development of a platform for quickly assessing the reliability and characterizing the behavior of hardware accelerators implemented on reconfigurable FPGAs when they are affected by such fault
SEcube™: Data at Rest and Data in Motion Protection
No full textCurrent trends for ubiquitous data usage have made information security as a mandatory component of any system. The availability of su itable levels of protection for data is required to secure any kind of content throughout its lifecycle and independently from the media, which allows the data to be used. In this paper we present a methodology to provide data protection through a simple and effective security abstraction layer based on the SEcube™ (Secure Environment cube) single chip, a new security-oriented open hardware and software platform . After analyzing the most critical information states, we introduce a set of easy-to-use APIs that provide an open-sour ce, multi-paradigm security layer, suitable to protect both dat a at rest and data in motion. Being the SEcube™ made up of three hardware elements (a highly powerful processor, a Common Criteria certified smartcard and a flexible FPGA) , all the functions are implemented and executed in a fully controlled secure environment. All the complexities related to key management and algorithms are handled within the secure environment, leaving the developers free to focus on the final applications and services
PORTING LEON3FT/GRLIB TO 4th GENERATION FLASH-BASED DEVICES
No full textCobham Gaisler develops the LEON3FT SPARC V8 fault-tolerant microprocessor that is available both as IP cores part of an IP library (GRLIB) that allows users to design their own custom system-on-chip (SoC) designs, and also as part of ready-made designs and devices.
Cobham Gaisler has recently added support for Microsemi IGLOO2, and experimental support for Microsemi radiation-tolerant RTG4, devices to GRLIB.
The presentation will give an overview of LEON processor system-on-chip architectures that are currently supported for the latest generation Microsemi devices and will provide an overview of the steps and obstacles in porting existing IP cores to these devices
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
A portable open-source controller for safe Dynamic Partial Reconfiguration on Xilinx FPGAs
Full text linkThanks to their flexibility, increasing performances and low Non-Recurrent Engineering costs, SRAM-based Field Programmable Gate Array (FPGA) devices often represent the preferred platforms for the final deployment of highly reliable systems. In this context, Dynamic Partial Reconfiguration (DPR) is far from being widely adopted due to the additional complexity introduced during the hardware design phase, and the dependability issues related to the FPGA reconfiguration process itself. This paper presents a portable open-source controller for safely enabling self dynamic and partial reconfiguration of systems implemented on Xilinx FPGAs. The controller embeds configurable error detection and correction circuitry that enables a safe DPR by monitoring for partial bitstreams data errors. Experiments highlight the high performances achieved and the limited hardware resources needed to implement it on different devices. The HDL source code has been made available through the popular open-source Cobham Gaisler GRLIB IP-cores librar
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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