1,721,548 research outputs found

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Preventing Soft Errors and Hardware Trojans in RISC-V Cores

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    Soft errors in embedded systems' memories like single-event upsets and multiple-bit upsets lead to data and instruction corruption. Therefore, devices deployed in harsh environments, such as space, use fault-tolerant processors or redundancy methods to ensure critical application dependability. Another rising concern in secure, critical space applications is the possible introduction of hardware Trojans in an untrusted phase of the manufacturing process. Besides environmental side-effects, an adversary that has injected a malicious mechanism e.g., in the processor or memory can trigger unwanted behavior or leak sensitive information. Techniques to prevent or mitigate hardware Trojans are important to ensure hardware security. Leveraging the openness of the RISC-V ISA, this paper introduces a novel solution to improve the security and dependability of softcores with a low area and latency overhead. The instruction validator which is the first part of this solution can effectively detect hardware Trojans and multiple-bit upsets in the instruction memory by checking instruction/address pairs using a Bloom filter probabilistic data structure. The second part of the solution is the proposal of an error correction code instruction memory using Hamming single-error correction to detect and correct single-event upsets. It has also been proven that the Hamming decoder improves the detection performance of the instruction validator.</p

    Variations on the Author

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    “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

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    We 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

    On the Analysis of Real-time Operating System Reliability in Embedded Systems

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    Nowadays, the reliability has become one of the main issues for safety-critical embedded systems, like automotive, aerospace and avionic. In an embedded system, the full system stack usually includes, between the hardware layer and the software/application layer, a middle layer composed by the Operating System (OS) and the middleware. Most of the time, in the literature only the application-layer is considered during the reliability analysis. This is due to the fact that middle layer short execution time makes the probability of a fault affecting it much lower compared to the application-level. Nevertheless, middle layer data structures lifespan is equivalent to the application layer ones. Moreover, all the times a hardware fault propagates to the middle-layer as an error, and especially to the OS, its impact can be expected to be potentially catastrophic. The aim of this work is to study the reliability of a Real-Time Operating System (RTOS) affected by Single Event Upset (SEU) faults. The methodology targets the most relevant variables and data structures of FreeRTOS analyzed through a software-based fault injection. Results show the ability to highlight the criticality in the OS fault tolerance, in terms of system integrity, data integrity and the overall inherent resiliency to faults, potentially leading to selective hardening of the OS.Accepted author manuscriptQuantum & Computer Engineerin
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