1,720,961 research outputs found
Impact of tungsten oxidation conditions on the performance of Al2O3/WOx-based CBRAM devices
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Impacts of Ta buffer layer and Cu-Ge-Te composition on the reliability of GeSe-based CBRAM
No full textGoing 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
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
Onderzoek van elektrische eigenschappen van toonaangevende geschaalde CBRAM devices gebruikmakend van nieuwe materialen voor toekomstige geheugentechnologieën
No full textThe global datasphere is predicted to grow from 33 zettabytes (ZB) in 2018 to 175 ZB by 2025. Ever increasing data is accelerated by the Internet of Things (IoT) and hyper personalisation of consumer life by behavioural modelling. Therefore, the development of novel data storage solutions has become more important than before. Among the different emerging memories, Conducting Bridge Random Access Memory (CBRAM) is a prime candidate for high density storage class memory (SCM) applications due to its ease of fabrication, scalability and high cycling endurance. The memory device consists of a solid electrolyte placed between an active and inert electrode constituting a Metal- Insulator-Metal (MIM) structure. The information is stored as device resistance, which can be switched between high and low values. The change in resistance is brought about by the voltage-controlled formation and dissolution of the active electrode metal filament in the electrolyte.
A low operating current (≤ 50 μA) is favourable for SCM devices in order to reduce current density requirements of the selector element. This enables 1-selector 1-resistor (1S1R) integration in large memory array blocks. However, at such low currents, the retention and variability of CBRAM devices are adversely affected by the small filament size controlled by the operating current.
The primary goal of this thesis is to optimise CBRAM single cells for stand- alone low power SCM. Different active electrode-electrolyte combinations are tested at an operating current of 50 μA. The impact of electrolyte composition, electrolyte thickness, tantalum buffer layer and copper supply alloying on the reliability properties of traditional copper CBRAM are investigated. Based on the findings, a novel Cu-GeSe CBRAM is developed for SCM applications. These devices can be switched with 10 μs pulses and show an extrapolated retention of > 10 years at 85°C, with no tailed distributions. In-depth studies using conduction and kinetic models are conducted to understand the origins of switching voltage and resistance variability in Cu-GeSe CBRAM devices.
In order to reduce the switching pulse widths further, we investigate Cu-CBRAM based on oxide electrolytes. We unravel the crucial role played by the electrically generated intrinsic oxygen vacancies on the switching and reliability of these devices. Finally, we develop a novel Co-based CBRAM through extensive active electrode screening based on theoretical considerations. Reliability investigations of Co-CBRAM with both oxide and chalcogenide electrolytes were performed for the first time, to our knowledge, in this thesis. The influence of multiple factors like thermal anneal, electrolyte alloying and electrolyte thickness on the electrical characteristics of Co devices are thoroughly analysed and pathways to improve the reliability are identified. Based on the findings, we develop a novel Co-GeSe CBRAM stack which shows an extrapolated retention of > 10 years at 85°C and can be switched with 1 μs pulses, ten times faster than Cu-GeSe CBRAM.status: Publishe
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