1,720,987 research outputs found
Floating gate devices: operations and compact modeling
No full textThe goal of this book is twofold. First, it explains the principles and physical mechanisms of Floating Gate device operations. Second, starting from a general overview on Compact Modeling issues, it illustrates features and details of a complete Compact Model of a Floating Gate device, the building block of Flash Memories, one of the “hottest” products in the semiconductor industry. Flash Memories are one of the most innovative and complex types of high-tech, nonvolatile memories in use today [see, for example, Proceedings of the IEEE, Special Issue on: Flash Memory Technology, April 2003]. Since their introduction in the early 1990s, these products have experienced a continuous evolution from the simple first products to emulate EPROM memories, to the extreme flexibility of design application in today products. This is an enabling technology: future limits are beyond our current expectations and limited only by our imagination.In the memory arena, Flash memory is the demonstration of the pervasive use of new electronic applications in our lives. Every new application can exploit this flexible and powerful memory technology, either as a stand-alone component or integrated as the enabling feature of the whole silicon integration.Flash are not just memories, they are “complex systems on silicon”: they are challenging to design, because a wide range of knowledge in electronics is required (both digital and analog), and they are difficult to manufacture. Physics, chemistry, and other fields must be integrated; and conditions must be carefully monitored and controlled in the manufacturing process.Memories demand massive investments in R&D, but they also reward with enormous potential market values. Flash memory market (considered the most important market segment among nonvolatile memories) is expected to progress at a very fast pace, and to gain the second place in the overall memory market. This is due to the optimization of cost/performance tradeoffs, and in particular to the inherent flexibility and versatility of this memory, which brings benefits in many applications.The leading application is in multimedia systems, which require memories that are increasingly larger in size, and demand ever-increasing performance characteristics. Telecommunications, computers, automotive and consumer electronics are some additional areas where these memories make possible numerous emerging applications.Moreover, the Flash memory integration is one of the irreplaceable requirements for further technological innovations, and particularly to realize the so-called system on silicon.Compact Model (CM) means an analytic model of the electrical behavior of a circuit element. Modeling is usually aimed at providing means to simulate the behavior of a device or a circuit by quantitative calculation. CM allows to highlight basic properties of a device, thus making easier the understanding and the synthesis of robust circuits. Therefore, the main intent of modeling is to forecast the behavior of a system. This holds for all integrated devices (resistors, capacitors, inductors, transistors, and also the device subject of this book: the floating gate device) and circuits. Compact Models of Floating Gate devices have the same purpose of all compact models: to be used within a program for circuit simulation. The Floating Gate transistor is the building block of a full array of memory cells and a memory chip. In a first approximation, the reading operation of a FG device, and for some cases also programming and erasing, can be considered a single-cell operation. Nevertheless, CMs are fundamental to simulate the effects of the cells not directly involved in the operation under investigation and the effects of the parasitic elements. Furthermore, they allow the simulation of the interaction with the rest of the device, and hence they are useful to check the design of the circuitry around the memory array: algorithms for cell addressing, charge pump sizing taking into account current consumption and voltage drops, etc..
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 New Compact Model of Floating Gate Non-Volatile Memory Cells
No full textThis paper presents a new compact model of Floating Gate Non-Volatile Memory Cells using SPICE circuit elements. It features many advantages compared to previous models: it is simple and easy to implement, scalable, and its computational time is not critical, thus making it very attractive to industry. It is based on a new procedure that improves the floating gate voltage estimate. The parameter extraction procedure is the same of a MOS transistor
A new compact DC model of floating gate memory cells without capacitive coupling coefficients
No full textThis paper presents for the first time a new compact SPICE model of floating gate nonvolatile memory cells capable to reproduce effectively its complete dc electrical behavior in every bias conditions. This model features many advantages compared to previous ones: it is simple and easy to implement since it uses SPICE circuit elements, is scalable, and its computational time is not excessive. It is based on a new procedure that calculates the floating gate voltage without using fixed capacitive coupling coefficients, thus improving the floating gate voltage estimate that is fundamental for the correct modeling of cell operations. Moreover, this model requires only the usual parameters adopted for SPICE-like models of MOS transistors plus the floating gate-control gate capacitance, making it very attractive to industry as the same parameter extraction procedure used for MOS transistors can be directly applied. The model we propose has been validated on (EPROM)-P-2 and Flash memory cells manufactured in existing technology (0.35 mum and 0.25 mum) by STMicroelectronics
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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