1,720,957 research outputs found
A 220-mV input, 8.6 step-up voltage conversion ratio, 10.45-Î1⁄4W output power, fully integrated switched-capacitor converter for energy harvesting
No full textThis paper presents a fully integrated step-up switched-capacitor DC-DC converter for energy harvesting applications. The proposed solution exhibits both a high voltage-conversion ratio and a high power-conversion efficiency from a low-voltage source such as a thermoelectric generator or an indoor solar cell. The circuit has been implemented in TSMC 55nm CMOS process. Measurements demonstrate that it can properly operate with a 220 mV input, providing a 1.9 V output voltage at 10.45 Î1⁄4W output power, with 37.4% power conversion efficiency. We demonstrate that it can be used as a power supply for a Bluetooth Low Energy beacon with a thermoelectric generator subjected to a temperature difference of only 3.5°C
A chopper stabilized, low power capacitance to PWM converter for sensor interfacing
No full textA low-power, low voltage capacitance to pulse duration converter with intrinsic low sensitivity to temperature and parasitic capacitances is presented. The circuit uses a dual clock chopper modulation, which significantly lowers the effects of device mismatch. An effective resolution of 7.2 bits with 3.8 uA supply current and operation down to 0.9 Vdd are demonstrated by means of electrical simulations performed on a prototype designed with the UMC 0.18 um process
An integrated thermal flow sensor for liquids based on a novel technique for electrical insulation
No full textA novel method to electrically insulate integrated thermal flow sensors from liquids is proposed. The sensor is fabricated with a post-processing technique applied to chips designed with a commercial CMOS process. A low cost packaging technique is used to convey the liquid to the sensing structures. After packaging, a simple technique is used to coat the flow channel and the chip area exposed to the fluid with silicone. Preliminary tests in water confirm the effectiveness of the proposed method
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Design of fully integrated switched-capacitor step-up converters for energy harvesting applications
No full textLo scopo di questa tesi di dottorato è lo studio dei circuiti di conversione DC-DC step-up e la progettazione di un convertitore per applicazioni di micro-energy harvesting. Questa tesi è concentrata sulle soluzioni a condensatori commutati, per la loro facilità di integrazione che implica un minore ingombro e di conseguenza costi minori. Per i convertitori DC-DC a condensatori commutati, abbiamo sviluppato un modello che consente di valutare l’efficienza di conversione di diverse soluzioni circuitali.
In questa tesi presentiamo un convertitore step-up DC-DC a condensatori commutati, totalmente integrato che lavora con basse tensioni di ingresso, per applicazioni di micro-energy harvesting. La soluzione proposta presenta sia un rapporto di conversione alto e una corrispondente efficienza elevata. Il circuito è stato implementato con un processo CMOS a 55-nm della TSMC. Le misure dimostrano che il circuito può funziona con una tensione di ingresso di soli 220 mV, fornendo in uscita una tensione di 1.9 V ed una potenza di 10.45 μW con una efficienza del 37.4%. Il confronto con altri lavori disponibili in letteratura su convertitori step-up per applicazioni di energy harvesting nel range di potenze del μW dimostra che il convertitore proposto presenta il rapporto di conversione più alto con tensioni di ingresso inferiori ai 250 mV. Il convertitore è stato testato anche con un generatore termoelettrico disponibile in commercio e con un ricetrasmettitore beacon Bluetooth Low Energy. Il risultato del test ha dimostrato che il convertitore riesce ad alimentare in maniera continua il beacon con soli 3.5°C di differenza di temperatura tra il piatto caldo e freddo del generatore termoelettrico
SVILUPPO DI MICROSISTEMI SU SINGOLO CHIP PER MISURE DI PORTATA DI LIQUIDI
No full textArgomento di questo lavoro di tesi sarà lo sviluppo di microsistemi su un unico chip per la misura di portata di liquidi, realizzati con sensori di flusso intelligenti, basati sul principio termico. La fabbricazione di tali dispositivi avviene attraverso un processo CMOS, unito ad una procedura post-processing.
Lo scopo significativo di questo lavoro di tesi sarà quello di analizzare il loro comportamento sia di nuovo con i gas, sia soprattutto con sostanze liquide e confrontare i risultati ottenuti
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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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