1,721,094 research outputs found
Profiling charge distributions in NROM devices
No full textNROM memory cells are proposed as one of the most promising non-volatile memories. Issues on scaling and endurance have risen due to the presence of both electrons and holes, for the control of their relative position and spread in the charge trapping material. Therefore, a deeper analysis of the injected-charge distribution region is very important for program/erase bias optimization, reliability prediction and future scaling. In this paper, we will introduce and discuss two tools, based on subthreshold slope and temperature effects, able to correctly estimate program charge distribution features from simple ID – VGS measurements
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
Hole Distributions in Erased NROM Devices: profiling method and effects on reliability
No full textThe NROM-cell concept has been introduced as a promising technology to replace Flash nonvolatile memory devices also in embedded products, owing to its intrinsic 2-b/cell operation and better endurance. However, the presence of physically sepa- rated electron and hole distributions generated by program and erase operations is reported to be one of the main causes of the device’s retention degradation. Therefore, a deep knowledge of the features and evolution of the nitride-storage charge is crucial for reliability, cell optimization, future scalability, and multilevel oper- ation. In this scenario, the purpose of this paper is twofold, which is as follows: 1) to introduce a combined simulative experimental method allowing profiling hole distribution in devices erased with different bias conditions and 2) to monitor through this technique the evolution of the nitride charge with cycling, correlating it to the degradation of memory reliability after cycling
Balanced CMOS LC-tank Analog Frequency Dividersfor Quadrature LO Generation
No full textA regenerative circuit based on an LC-tank balanced divider is proposed in this paper for quadrature LO signal generation. For given tank quality factor, it provides larger operation bandwidth and improved quadrature accuracy when compared with conventional injection locked frequency dividers. The operation bandwidth can be adjusted dynamically simply regulating the biasing current. Experimental results, carried on 0.18 μm CMOS prototypes, show 42% range with a tank quality factor of 13.5 while driving 1.5pF output capacitance. At the band edge, biasing current is 8mA. Quadrature accuracy has been verified through the achievable image rejection of a purposely developed single side band up-converter. Measurements, performed on five samples, show a minimum image rejection of 44dB.A regenerative circuit based on an LC-tank balanced divider is proposed in this paper for quadrature LO signal generation. For given tank quality factor, it provides larger operation bandwidth and improved quadrature accuracy when compared with conventional injection locked frequency dividers. The operation bandwidth can be adjusted dynamically simply regulating the biasing current. Experimental results, carried on 0.18μm CMOS prototypes, show 42% range with a tank quality factor of 13.5 while driving 1.5pF output capacitance. At the band edge, biasing current is 8mA. Quadrature accuracy has been verified through the achievable image rejection of a purposely developed single side band up-converter. Measurements, performed on five samples, show a minimum image rejection of 44dB. © 2005 IEEE
Modeling and Optimization of a Solar Energy Harvester System for Self-Powered Wireless Sensor Networks
No full textIn this paper, we propose a methodology for optimizing a solar harvester with maximum power point tracking for self-powered wireless sensor network (WSN) nodes. We focus on maximizing the harvester's efficiency in transferring energy from the solar panel to the energy storing device. A photovoltaic panel analytical model, based on a simplified parameter extraction procedure, is adopted. This model predicts the instantaneous power collected by the panel helping the harvester design and optimization procedure. Moreover, a detailed modeling of the harvester is proposed to understand basic harvester behavior and optimize the circuit. Experimental results based on the presented design guidelines demonstrate the effectiveness of the adopted methodology. This design procedure helps in boosting efficiency, allowing to reach a maximum efficiency of 85% with discrete components. The application field of this circuit is not limited to self-powered WSN nodes; it can easily be extended in embedded portable applications to extend the battery life
A new model of tunnelling current and SILC in ultra-thin oxides
No full textWe propose a new double-box model of the oxide conduction band of MOS devices, aiming to quantitatively predict the gate current across ultra-thin oxides. Simulations nicely fit the experimental quantum oscillations of the gate current in the Fowler-Nordheim tunnelling regime. The oscillation period of the gate current has been empirically correlated with the oxide thickness. The low-field Stress Induced Leakage Current can be fitted by our model as well, by inserting oxide traps mediating an inelastic trap-assisted tunnelling
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
- …
