Novel High Performance Ultra Low Power Static Random Access Memories (SRAMs) Based on Next Generation Technologies

Title from PDF of title page viewed January 27, 2021Dissertation advisor: Masud H. ChowdhuryVitaIncludes bibliographical references (page 107-120)Thesis (Ph.D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2019Next Big Thing Is Surely Small: Nanotechnology Can Bring Revolution. Nanotechnology leads the world towards many new applications in various fields of computing, communication, defense, entertainment, medical, renewable energy and environment. These nanotechnology applications require an energy-efficient memory system to compute and process. Among all the memories, Static Random Access Memories (SRAMs) are high performance memories and occupies more than 50% of any design area. Therefore, it is critical to design high performance and energy-efficient SRAM design. Ultra low power and high speed applications require a new generation memory capable of operating at low power as well as low execution time. In this thesis, a novel 8T SRAM design is proposed that offers significantly faster access time and lowers energy consumption along with better read stability and write ability. The proposed design can be used in the conventional SRAM as well as in computationally intensive applications like neural networks and machine learning classifiers [1]-[4]. Novel 8T SRAM design offers higher energy efficiency, reliability, robustness and performance compared to the standard 6T and other existing 8T and 9T designs. It offers the advantages of a 10T SRAM without the additional area, delay and power overheads of the 10T SRAM. The proposed 8T SRAM would be able to overcome many other limitations of the conventional 6T and other 7T, 8T and 9T designs. The design employs single bitline for the write operation, therefore the number of write drivers are reduced. The defining feature of the proposed 8T SRAM is its hybrid design, which is the combination of two techniques: (i) the utilization of single-ended bitline and (ii) the utilization of virtual ground. The single-ended bitline technique ensures separate read and write operations, which eventually reduces the delay and power consumption during the read and write operations. It's independent read and write paths allow the use of the minimum sized access transistors and aid in a disturb-free read operation. The virtual ground weakens the positive feedback in the SRAM cell and improves its write ability. The virtual ground technique is also used to reduce leakages. The proposed design does not require precharging the bitlines for the read operation, which reduces the area and power overheads of the memory system by eliminating the precharging circuit. The design isolates the storage node from the read path, which improves the read stability. For reliability study, we have investigated the static noise margin (SNM) of the proposed 8T SRAM, for which, we have used two methods – (i) the traditional SNM method with the butterfly curve, (ii) the N-curve method A comparative analysis is performed between the proposed and the existing SRAM designs in terms of area, total power consumption during the read and write operations, and stability and reliability. All these advantages make the proposed 8T SRAM design an ideal candidate for the conventional and computationally intensive applications like machine learning classifier and deep learning neural network. In addition to this, there is need for next generation technologies to design SRAM memory because the conventional CMOS technology is approaching its physical and performance boundaries and as a consequence, becoming incompatible with ultra-low-power applications. Emerging devices such as Tunnel Field Effect Transistor (TFET)) and Graphene Nanoribbon Field Effect Transistor (GNRFET) devices are highly potential candidates to overcome the limitations of MOSFET because of their ability to achieve subthreshold slopes below 60 mV/decade and very low leakage currents [6]-[9]. This research also explores novel TFET and GNRFET based 6T SRAM. The thesis evaluates the standby leakage power in the Tunnel FET (TFET) based 6T SRAM cell for different pull-up, pull-down, and pass-gate transistors ratios (PU: PD: PG) and compared to 10nm FinFET based 6T SRAM designs. It is observed that the 10nm TFET based SRAMs have 107.57%, 163.64%, and 140.44% less standby leakage power compared to the 10nm FinFET based SRAMs when the PU: PD: PG ratios are 1:1:1, 1:5:2 and 2:5:2, respectively. The thesis also presents an analysis of the stability and reliability of sub-10nm TFET based 6T SRAM circuit with a reduced supply voltage of 500mV. The static noise margin (SNM), which is a critical measure of SRAM stability and reliability, is determined for hold, read and write operations of the 6T TFET SRAM cell. The robustness of the optimized TFET based 6T SRAM circuit is also evaluated at different supply voltages. Simulations were done in HSPICE and Cadence tools. From the analysis, it is clear that the main advantage of the TFET based SRAM would be the significant improvement in terms of leakage or standby power consumption. Compared to the FinFET based SRAM the standby leakage power of the T-SRAMs are 107.57%, 163.64%, and 140.44% less for 1:1:1, 1:5:2 and 2:5:2 configurations, respectively. Since leakage/standby power is the primary source of power consumption in the SRAM, and the overall system energy efficiency depends on SRAM power consumption, TFET based SRAM would lead to massive improvement of the energy efficiency of the system. Therefore, T-SRAMs are more suitable for ultra-low power applications. In addition to this, the thesis evaluates the standby leakage power of types of Graphene Nanoribbon FETs based 6T SRAM bitcell and compared to 10nm FinFET based 6T SRAM bitcell. It is observed that the 10nm MOS type GNRFET based SRAMs have 16.43 times less standby leakage power compared to the 10nm FinFET based SRAMs. The double gate SB-GNRFET based SRAM consumes 1.35E+03 times less energy compared to the 10nm FinFET based SRAM during write. However, during read double gate SB-GNRFET based SRAM consume 15 times more energy than FinFET based SRAM. It is also observed that GNRFET based SRAMs are more stable and reliable than FinFET based SRAM.Introduction -- Background -- Novel High Performance Ultra Low Power SRAM Design -- Tunnel FET Based SRAM Design -- Graphene Nanoribbon FET Based SRAM Design -- Double-gate FDSOI Based SRAM Designs -- Novel CNTFET and MEMRISTOR Based Digital Designs -- Conclusio

Novel Non Precharging Single Bitline 8T Static Random Access Memory

Title from PDF of title page viewed August 25, 2017Thesis advisor: Masud H ChowdhuryVitaIncludes bibliographical references (pages 39-41)Thesis (M.S.)--School of Computing and Engineering. University of Missouri-Kansas City, 2016Novel 8T SRAM design, employs individual bit-line (BL) and word-line (WL) for each operation. The read operation uses read word-line (RWL) and read bit-line (RBL) respectively. On other hand the write operation employs write word-line (WWL) and write bit line (WBL). Due to single BL and WL the power consumption of the proposed 8T SRAM cell is significantly less.The proposed design avoids the stability and reliability issues of the conventional 6T and other existing SRAM cells. The read stability and the write ability of the proposed design are better compared to the standard 6T and other 7T, 8T and 9T SRAM designs. The proposed 8T SRAM is as good as the 10T design without the overheads. The power consumption of the proposed 8T SRAM cell is significantly lower than other SRAM cells. The proposed design is ratio-less, which makes the construction and operation of the proposed SRAM much simpler and the response time much faster. The proposed cell design and its reliability and stability have been analyzed for 45nm technology. We have also analyzed the static noise margin (SNM) and the stability of the proposed design. In this analysis, we have used three methods. First, the traditional SNM method with the butterfly curve is introduced. Second, the N-curve method is used. And finally, we used the bit-line voltage method. We have also analyzed the impact of some process and parametric variations. The write ability of the proposed design is also compared to that of the conventional 6T SRAM.Introduction -- Existing SRAM designs -- Proposed 8T SRAM -- Analysis of power and area overheads of the proposed 8T SRAM -- Stability analysis of the proposed 8T SRAM -- Analysis of process and parametric variation in the proposed 8T SRAM -- Monte Carlo analysis -- Conclusio

A clinical study of arrhythmias associated with acute coronary syndrome: a hospital based study of a high risk and previously undocumented population

Background: ACS represents a global epidemic. Arrhythmia in ACS is common. Careful investigation may lead to further improvement of prognosis. Retrospectively analyzed the year- round data of our center. Study was undertaken to analyze the incidence, frequency and type of arrhythmias in ACS. This is to aid timely intervention and to modify the outcome. Identification of the type of arrhythmia is of therapeutic and prognostic importance.Methods: This cross sectional analytical study was conducted in the Department of Cardiology, Apollo Hospitals Dhaka, from January 2019 to January 2020 with ACS patients. Enrolled consecutively and data analyzed.Results: There were 500 patients enrolled considering inclusion and exclusion criteria. Sample was subdivided into 3 groups on the type of ACS. Group-I with UA, Group-II with NSTE - ACS and Group-III with STE - ACS. Different types of arrhythmia noted. Types of arrhythmia were correlated with type of ACS. 500 patients included. Mean age 55.53±12.70, 71.6% male and 28.4% female. 60.4% hypertensive, 46.2% diabetic, 20.2% positive family history of CAD, 32.2% current smoker, 56.4% dyslipidaemic and 9.6% asthmatic. 31.2% UA, 39.2% NSTE-ACS and 29.6% STE-ACS. Type of arrhythmias noted. 22% sinus tachycardia, 20.2% sinus bradycardia, 9% atrial fibrillation, 5.2% ventricular ectopic, 4.8% supra ventricular ectopic, 2.8% bundle branch block, 2.2% atrio-ventricular block, 1% broad complex tachycardia, 0.4% narrow complex tachycardia, 0.2% sinus node dysfunction and 32.2% without any arrhythmia. Significant incidences of arrhythmia detected - respectively 29.8%, 39.2% and 31%, p<0.001.Conclusions: In conclusion, arrhythmias in ACS are common. More attention should be paid to improve their treatment and prognosis

Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial

Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma. Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding. Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries. Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to 100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable. This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124. Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid (5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18). Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of 5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98). Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a randomised trial

Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens

A Ranking Learning Model by K-Means Clustering Technique for Web Scraped Movie Data

Business organizations experience cut-throat competition in the e-commerce era, where a smart organization needs to come up with faster innovative ideas to enjoy competitive advantages. A smart user decides from the review information of an online product. Data-driven smart machine learning applications use real data to support immediate decision making. Web scraping technologies support supplying sufficient relevant and up-to-date well-structured data from unstructured data sources like websites. Machine learning applications generate models for in-depth data analysis and decision making. The Internet Movie Database (IMDB) is one of the largest movie databases on the internet. IMDB movie information is applied for statistical analysis, sentiment classification, genre-based clustering, and rating-based clustering with respect to movie release year, budget, etc., for repository dataset. This paper presents a novel clustering model with respect to two different rating systems of IMDB movie data. This work contributes to the three areas: (i) the &ldquo;grey area&rdquo; of web scraping to extract data for research purposes; (ii) statistical analysis to correlate required data fields and understanding purposes of implementation machine learning, (iii) k-means clustering is applied for movie critics rank (Metascore) and users&rsquo; star rank (Rating). Different python libraries are used for web data scraping, data analysis, data visualization, and k-means clustering application. Only 42.4% of records were accepted from the extracted dataset for research purposes after cleaning. Statistical analysis showed that votes, ratings, Metascore have a linear relationship, while random characteristics are observed for income of the movie. On the other hand, experts&rsquo; feedback (Metascore) and customers&rsquo; feedback (Rating) are negatively correlated (&minus;0.0384) due to the biasness of additional features like genre, actors, budget, etc. Both rankings have a nonlinear relationship with the income of the movies. Six optimal clusters were selected by elbow technique and the calculated silhouette score is 0.4926 for the proposed k-means clustering model and we found that only one cluster is in the logical relationship of two rankings systems

Seroprevalence of bovine viral diarrhea virus in crossbred dairy cattle in Bangladesh

Aim: The study was conducted to determine the seroprevalence of bovine viral diarrhea virus (BVDV) and hematological features in crossbred dairy cattle in Chittagong, Bangladesh. Materials and Methods: The antibody against BVDV in crossbred dairy cattle serum was detected by indirect enzyme-linked immunosorbent assay. The association of different categorical variables in the prevalence of BVDV has been studied. Blood samples were collected and analyzed to know the hematological variations in the study population. Results: The overall seroprevalence of BVDV in the study area was 51.1% (95% confidence interval [CI], 40.5-61.5). Among different physiological stages of animals, the highest 57.1% (95% CI, 42.2-71.2) prevalence was in case of non-pregnant animals. Aborted cows were found to be significantly (p<0.05) more seropositive 77.8% (95% CI, 52.4-93.6) than the non-aborted cows (77.8%, 95% CI, 52.4-93.6, compared to 44.7%, 95% CI, 33.3-56.6, respectively). Cows having the history of retained placenta were found more positive than without the history of retained placenta (63.2%, 95% CI, 38.4-83.7, compared to 54.7%, 95% CI, 40.4-68.4, respectively). Among the animals of different age groups, BVDV seroprevalence was higher 61.3% (95% CI, 42.2-78.2) in animals of more than 3 years up to 5 years, whereas 32% was in case of 0-1-year-old. Significant variation found in different geographical areas of the study area. Hematological analyses have shown variation between the BVDV positive and negative animals. Conclusion: Seroprevalence of BVDV found to be high in the study area is also economically important and cause significant damage to the production industry. Therefore, it is necessary to conduct effective control measures to reduce the burden of BVDV

Phytochemical screening and in vitro evaluation of antioxidant and antimicrobial efficacies of Pteropyum scoparium (Jaub. &amp; Spach) Sidaf crude extracts

Objective: Pteropyrum scoparium Jaub. &amp; Spach locally known as “Sidaf” is a meal known to the ancient Omani people with many health benefits. It is traditionally used in Oman to treat high cholesterol, hypertension, indigestion problems, wound healing, and diabetes. However, these claims are yet to be scientifically proven. Hence, this study aimed to perform phytochemical, antioxidant, and antimicrobial analysis of P. scoparium leaves aqueous and alcoholic extracts to confirm its medicinal potential. Methods: A detailed phytochemical analysis of ethanol and aqueous extracts of leaves was carried out to confirm the presence of bioactive substances. DPPH (2,2′-diphenyl-1-picrylhydrazyl), agar-well diffusion and disc diffusion methods were used to evaluate antioxidant and antimicrobial potential, respectively. The extracts were tested against four microorganisms viz. E. coli (ATCC 25922), S. aureus (ATCC 23235), Penicillium sp. (ATCC 11597) and Rhizopus stolonifer (ATCC 14037). Results: The ethanol extract exhibited higher DPPH scavenging activity than aqueous extract that was confirmed with IC50 values of both extracts. However, the aqueous extract was found to be significantly more effective as an antimicrobial agent than the ethanol extract. This could be due to higher coumarins content that is thrice as much as in ethanol extract. One-way repeated measure RM ANOVA showed that there was a statistically significant difference in the antimicrobial susceptibility of all four organisms for the aqueous and ethanol well diffusion extracts (DF = 7; SS = 56.350, MS = 8.050; F = 5.865; P < 0.001). The highest mean zone of inhibition was recorded for S. aureus (12 ± 3.851 mm) well diffusion aqueous extract followed by R. stolonifer (11.750 ± 4.250 mm) well diffusion aqueous extract, and S. aureus (10.625 ± 3.771 mm) well diffusion ethanol extract. Conclusions: Phytochemical screening of ethanol and aqueous extracts revealed the presence of alkaloids, glycosides, carbohydrates, amino acid, fats &amp; fixed oils, phenolic compounds &amp; tannins, proteins, phytosterols, saponins, gum &amp; mucilage, terpenoids, coumarins and anthocyanins. The findings from this study will be useful in evaluating the phytochemical constituents present in the extract and developing commercial drugs as antioxidant and antimicrobial agents based on this plant