Energy Efficient Design for Deep Sub-micron CMOS VLSIs

Over the past decade, low power, energy efficient VLSI design has been the focal point of active research and development. The rapid technology scaling, the growing integration capacity, and the mounting active and leakage power dissipation are contributing to the growing complexity of modern VLSI design. Careful power planning on all design levels is required. This dissertation tackles the low-power, low-energy challenges in deep sub-micron technologies on the architecture and circuit levels. Voltage scaling is one of the most efficient ways for reducing power and energy. For ultra-low voltage operation, a new circuit technique which allows bulk CMOS circuits to work in the sub-0. 5V supply territory is presented. The threshold voltage of the slow PMOS transistor is controlled dynamically to get a lower threshold voltage during the active mode. Due to the reduced threshold voltage, switching speed becomes faster while active leakage current is increased. A technique to dynamically manage active leakage current is presented. Energy reduction resulting from using the proposed structure is demonstrated through simulations of different circuits with different levels of complexity. As technology scales, the mounting leakage current and degraded noise immunity impact performance especially that of high performance dynamic circuits. Dual threshold technology shows a good potential for leakage reduction while meeting performance goals. A model for optimally selecting threshold voltages and transistor sizes in wide fan-in dynamic circuits is presented. On the circuit level, a novel circuit level technique which handles the trade-off between noise immunity and energy dissipation for wide fan-in dynamic circuits is presented. Energy efficiency of the proposed wide fan-in dynamic circuit is further enhanced through efficient low voltage operation. Another direct consequence of technology scaling is the growing impact of interconnect parasitics and process variations on performance. Traditionally, worst case process, parasitics, and environmental conditions are considered. Designing for worst case guarantees a fail-safe operation but requires a large delay and voltage margins. This large margin can be recovered if the design can adapt to the actual silicon conditions. Dynamic voltage scaling is considered a key enabler in reducing such margin. An on-chip process identifier to recover the margin required due to process variations is described. The proposed architecture adjusts supply voltage using a hybrid between the one-time voltage setting and the continuous monitoring modes of operation. The interconnect impact on delay is minimized through a novel adaptive voltage scaling architecture. The proposed system recovers the large delay and voltage margins required by conventional systems by closely tracking the actual critical path at anytime. By tracking the actual critical path, the proposed system is robust and more energy efficient compared to both the conventional open-loop and closed-loop systems

BACH ARRAY LINEAR GENERATOR FOR WAVE ENERGY CONVERTERS

linear generators have been proposed as a proper power takeoff system for direct-drive wave energy conversion. Coupled directly to a reciprocating wave energy device, it was declared that linear generators could be a valuable replacement for hydraulic and pneumatic systems. In this paper, the design and performance evaluation of permanent magnet linear generator that implements Halbach array arrangement is established. The designed generator is suitable for direct energy extraction from sea waves at small wave amplitude. The electromagnetic design is performed using finite element method and space harmonic analysis. A comparative study is performed between Halbach array and conventional air-cored linear generators to show the effectiveness of the proposed design. The equivalent circuit based model is utilized to investigate the dynamic performance of the Halbach array generator. The simulated dynamic performance of the designed generator clarifies that the implementation of Halbach array arrangement would improve energy extraction and voltage waveform

Possible ways in research in portuguese language & its literatures

In this article, we revise possible paths in Luso-Brazilian language and its literatures research between the decade of 1970 until the year of 2020. We start from section of the meanings of linguistic, literary, translational, touristic and educational experiences of human language: signifying, communicating and interacting. The complexity of these experiences in Portuguese Language takes on meaning through interdisciplinary and interculturality, providing a dialogue between various cultural groups that meet through that language, or in studies and researches in this field or in a language learning.Neste artigo, busca-se revisar os possíveis caminhos na pesquisa luso-brasileira em língua portuguesa e suas literaturas entre os anos de 1970 até o ano de 2020. Partimos nesse recorte da nossa experiência no ensino e na pesquisa em língua portuguesa no contexto egípcio, ressaltando os sentidos linguístico, literário, tradutório, turístico e educativo da linguagem humana em três eixos: o significar, o comunicar e o interagir. A complexidade dessas experiências em língua portuguesa ganha relevância por meio da interdisciplinaridade e da interculturalidade, proporcionando um diálogo entre os diversos grupos culturais que se encontram nessa língua, sejam nos estudos e pesquisas do campo ou no aprendizado da língua

Itinerários acadêmicos

Trata-se de um diário acadêmico dos itinerários percorridos pelo autor desde sua formação em língua espanhola, língua árabe e língua inglesa no Egito, passando pelo mestrado em linguística na Colômbia e terminando pelo doutorado em Estudos Comparados em língua portuguesa na USP

Optimal Sizing of Standalone PV-Wind Hybrid Energy System in Rural Area North Egypt

This paper studies the sizing of stand-alone renewable energy system applied in rural areas in the north of Egypt. The available renewable energy sources in these areas are investigated to be integrated to supply the different types of electrical loads. The quality and quantity of these sources over various weather and climate changes are studied to construct a robust energy system. The load demand in such areas is determined according to all activities require electrical energy. This study considers the different economic levels and technologies which affect the load demand value. The technique and economical indices required to obtain the optimal are investigated and applied in the various estimated cases. The genetic algorithm (GA) technique is applied to determine the size and number of photovoltaic panels and wind turbines. The obtained solution takes into account the loss of power supply probability and the minimization of system cost. This study presents an essential phase in the sustainable development of such rural areas

EGYPT IN INTERFACE BETWEEN DIARY OF DOM PEDRO II AND THE NEWSPAPERS “DIÁRIO DE MARANHÃO” AND “DIÁRIO DO RIO DE JANEIRO” IN 1876 AND 1877

Este artigo analisa a história do imaginário do Egito e a técnica da “escrita de si” no “Diário de Dom Pedro II” na sua viagem a esse país entre 1876 e 1877, em interface com os jornais “Diário do Maranhão” e “Diário do Rio de Janeiro” na mesma época. As notícias dos jornais foram analisadas, colocando essas informações jornalísticas em diálogo com a textura literária e memorialista do “Diário de Dom Pedro II”, a partir do “mapeamento” dos lugares afetivos percorridos pelo monarca no seu “Diário”. As interpretações sociais, interdisciplinares e interculturais dessas informações podem abrir caminhos de diálogo e intercompreensão entre árabes, africanos e brasileiros no século XXI.This article analyzes the history of the imaginary of Egypt and the technique of “writing the self” in “Diary of Don Pedro II” in his travel to that country between 1876 and 1877, in interface with the newspapers “Diário de Maranhão” and “Diário do Rio de Janeiro” at the same time. News stories were analyzed, putting this journalistic information with literary & memorialistic texture of “Diary of Don Pedro II”, by mapping the affective places of “Dom Pedro de Alcântara” in the Diary

Titanium elastic nails versus spica cast in pediatric femoral shaft fractures:A systematic review and meta-analysis of 1012 patients

Background: There is a general consensus on the management of femoral fractures in children younger than two years and adolescents older than sixteen years. The best treatment for patients younger than sixteen years of age is still debatable. Titanium Elastic Nails (TEN), is widely used with some evidence, nonetheless, we undertook a systematic meta-analysis to assess the efficacy of TEN compared to Spica cast for the management of femoral shaft fracture in children aged between 2 to 16 years old. Methods: A computer literature search of PubMed, Scopus, Web of Science, CINAHL and Cochrane Central was conducted using relevant keywords. We included clinical trials and observational studies that compared TEN versus Spica cast; Records were screened for eligible studies and data were extracted and synthesized using Review Manager version 5.3 for Windows. Our search found 573 unique articles. After screening the abstract and relevant full text, 12 studies with a total of 1012 patients were suitable for the final analysis. Results: In terms terms of union (in weeks), the reported effect sizes favoured the TEN group in two included studies only. Moreover, the overall standardized mean difference in sagittal (SMD -0.48, 95% CI [-0.70 to -0.26], P<0.001) and coronal angulations (SMD -0.66, 95% CI [-1.00 to -0.31], P<0.001) favored TEN fixation in management of femoral fractures younger than 16 years. The reported length of hospital stay was not consistent across studies. The overall risk ratio of malalignment (RR=0.39, 95% CI [0.27 to 0.57], P<0.001) favored the TEN as well as walking independently. Based on our analysis, TEN treatment is superior to traction and hip spica for femoral fractures in patients younger than 16 years old. Conclusion: Based on our analysis we recommend the use of TEN fixation in management of pediatric femoral fractures in patients younger than 16 years

Visfatin versus Flow-Mediated Dilatation as a Marker of Endothelial Dysfunction in Pediatric Renal Transplant Recipients

BACKGROUND: Renal transplantation (RTx) is the treatment of choice for paediatric end-stage renal disease (ESRD). A major cause of morbidity and mortality after RTx is cardiovascular disease. Independent predictors of cardiovascular events were shown to constitute an endothelial dysfunction (ED). This study aims to evaluate Visfatin serum level in comparison to brachial artery flow-mediated dilatation (FMD) as a marker of endothelial dysfunction in paediatric RTx recipients.METHODS: Visfatin serum level has been evaluated in 30 patients on regular hemodialysis (HD), 36 patients post-RTx and 30 controls as a measure for ED, and has been compared to brachial artery FMD.RESULTS: Visfatin level in transplant recipients was significantly lower than the hemodialysis group as well as FMD was better in transplant recipients. In spite of marked improvement of FMD and marked reduction of visfatin in post-RTx no direct statistical correlation was found between serum Visfatin level and flow-mediated dilatation.CONCLUSION: Pediatric RTx recipients show lower serum Visfatin level and better FMD than those on regular hemodialysis, reflecting less endothelial dysfunction (ED) and less cardiovascular risk. FMD in kidney transplant recipients tends to be less than normal subjects while visfatin level of the same group is similar to controls. Pediatric RTx appears to have a positive impact on the growth development of children with ESRD

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially