Virtualized execution runtime for FPGA accelerators in the cloud

FPGAs offer high performance coupled with energy efficiency, making them extremely attractive computational resources within a cloud ecosystem. However, to achieve this integration and make them easy to program, we first need to enable users with varying expertise to easily develop cloud applications that leverage FPGAs. With the growing size of FPGAs, allocating them monolithically to users can be wasteful due to potentially low device utilization. Hence, we also need to be able to dynamically share FPGAs among multiple users. To address these concerns, we propose a methodology and a runtime system that together simplify the FPGA application development process by providing: 1) a clean abstraction with high-level APIs for easy application development; 2) a simple execution model that supports both hardware and software execution; and 3) a shared memory-model which is convenient to use for the programmers. Akin to an operating system on a computer, our lightweight runtime system enables the simultaneous execution of multiple applications by virtualizing computational resources, i.e., FPGA resources and on-board memory, and offers protection facilities to isolate applications from each other. In this paper, we illustrate how these features can be developed in a lightweight manner and quantitatively evaluate the performance overhead they introduce on a small set of applications running on our proof of concept prototype. Our results demonstrate that these features only introduce marginal performance overheads. More importantly, by sharing resources for simultaneous execution of multiple user applications, our platform improves FPGA utilization and delivers higher aggregate throughput compared to accessing the device in a time-shared manner

FPGAs for the Masses: Affordable Hardware Synthesis from Domain-Specific Languages

Field Programmable Gate Arrays (FPGAs) have the unique ability to be configured into application-specific architectures that are well suited to specific computing problems. This enables them to achieve performances and energy efficiencies that outclass other processor-based architectures, such as Chip Multiprocessors (CMPs), Graphic Processing Units (GPUs) and Digital Signal Processors (DSPs). Despite this, FPGAs are yet to gain widespread adoption, especially among application and software developers, because of their laborious application development process that requires hardware design expertise. In some application areas, domain-specific hardware synthesis tools alleviate this problem by using a Domain-Specific Language (DSL) to hide the low-level hardware details and also improve productivity of the developer. Additionally, these tools leverage domain knowledge to perform optimizations and produce high-quality hardware designs. While this approach holds great promise, the significant effort and cost of developing such domain-specific tools make it unaffordable in many application areas. In this thesis, we develop techniques to reduce the effort and cost of developing domain-specific hardware synthesis tools. To demonstrate our approach, we develop a toolchain to generate complete hardware systems from high-level functional specifications written in a DSL. Firstly, our approach uses language embedding and type-directed staging to develop a DSL and compiler in a cost-effective manner. To further reduce effort, we develop this compiler by composing reusable optimization modules, and integrate it with existing hardware synthesis tools. However, most synthesis tools require users to have hardware design knowledge to produce high-quality results. Therefore, secondly, to facilitate people without hardware design skills to develop domain-specific tools, we develop a methodology to generate high-quality hardware designs from well known computational patterns, such as map, zipWith, reduce and foreach; computational patterns are algorithmic methods that capture the nature of computation and communication and can be easily understood and used without expert knowledge. In our approach, we decompose the DSL specifications into constituent computational patterns and exploit the properties of these patterns, such as degree of parallelism, interdependence between operations and data-access characteristics, to generate high-quality hardware modules to implement them, and compose them into a complete system design. Lastly, we extended our methodology to automatically parallelize computations across multiple hardware modules to benefit from the spatial parallelism of the FPGA as well as overcome performance problems caused by non-sequential data access patterns and long access latency to external memory. To achieve this, we utilize the data-access properties of the computational patterns to automatically identify synchronization requirements and generate such multi-module designs from the same high-level functional specifications. Driven by power and performance constraints, today the world is turning to reconfigurable technology (i.e., FPGAs) to meet the computational needs of tomorrow. In this light, this work addresses the cardinal problem of making tomorrow's computing infrastructure programmable to application developers

S Transform: Time Frequency Analysis & Filtering

The S transform, a hybrid of the Short Time Fourier Transform and Wavelet transform, has a time frequency resolution which is far from ideal. This thesis proposes a modified S transform, which offers better time frequency resolution compared to the original S transform. The improvement is achieved through the introduction of a new scaling rule for the Gaussian window used in S transform. The S transform analysis of financial time series revealed the presence of business cycles, which could help forecasting economic booms and recessions. A noisy time series, with both signal and noise varying in frequency and in time, presents special challenges for improving the signal to noise ratio. The modified S-transform time-frequency representation is used to filter a synthetic time series in a two step filtering process. The filter method appears robust within a wide range of background noise levels. The new filtering approach developed was successfully applied for the identification of Post Glacial rebound in Eastern Canada

A Single Blinded Randomised Controlled Trial on the Efficacy of Adjunctive Collagen Cross-Linking in Healing of Suppurative Corneal Ulcers

INTRODUCTION: The cornea is the clear transparent dome shaped anterior-most part of the eyeball that serves as the major refracting surface for focusing of images on the retina. Infectious keratitis, or suppurative corneal ulcer, is characterized by a corneal epithelial defect with underlying stromal inflammation and destruction caused by multiplying organisms and their toxins. Associated uveal tissue and anterior chamber inflammation also occur. Collagen cross-linking (CXL), a procedure routinely used for control of progression of keratoconus, has been found to have beneficial effects on many types of corneal ulcers. An observational pilot study in our institution in 2013-2014, demonstrated a beneficial effect of CXL in suppurative corneal ulcers. OBJECTIVES: Primary objective: To determine the benefit of adjunctive collagen cross linking (cxl) in reduction of the “time to healing” of suppurative corneal ulcer. Secondary objectives: 1. To determine any difference in treatment failure rate (rates of perforation/keratoplasty/evisceration) of corneal ulcers treated with cxl as compared to the control group. 2. To assess the effect of risk factors (size of ulcer/diabetic status/type of organism)in outcome of corneal ulcer treatment with cxl compared to controls. METHODS: Study Design: Single-Blinded, Randomized, Controlled Clinical Trial conducted at Department of Ophthalmology, Christian Medical College, Schell Campus, Vellore. The study had two arms: Interventional group: Patients with infective corneal ulcer who satisfy the inclusion and exclusion criteria on standard medical therapy randomized to adjunctive COLLAGEN CROSS-LINKING (CXL) Comparative group: Patients with infective corneal ulcer who satisfy the inclusion and exclusion criteria on standard medical therapy randomized to SHAM CXL. Patients with suppurative corneal ulcers were admitted after routine microbiological analysis (scraping for smear and culture), and assessed on a daily basis to determine response to treatment. All patients who fit the inclusion and exclusion criteria and were randomized tointerventional and control group. Inclusion Criteria: 1. Adults greater than 18 years of age. 2. Corneal ulcer size of 2mm to 6mm. 3. Ulcer infiltrate depth upto 2/3 of the corneal thickness. 4. Smear and/or culture positive for fungus or bacteria. 5. Patients who are willing for inpatient care. Exclusion Criteria: 1. Suspected viral keratitis. 2. Suspected acanthamoeba keratitis. 3. Corneal thinning greater than 50% on clinical assessment at presentation. 4. Any pre-existing corneal pathology. 5. History of previous collagen cross-linking. 6. Patients who are unable or unwilling to give consent. RESULTS: Our pilot study conducted in 2014 showed clinically significant reduction in duration of healing post adjunctive treatment of corneal ulcers with CXL. The present study is a randomized control trial to study the effectiveness of crosslinking as an adjuvant therapy in healing of ulcers. 44 patients were recruited fitting the inclusion criteria and were randomized to an Intervention group and sham cross linking (Control) group. 17 patients in each group completed treatment. All patients received topical antimicrobial therapy. Within 48 hours of enrollment either crosslinking or placebo treatment was started. Each patient in the study group received maximum of three sessions of cross linking. Symptom relief and time of healing were noted. The results were compared between the Intervention group and the Control group. Both groups showed similar healing time of 29.85 days of healing of ulcers, as well as similar success and failure rates. There was no difference in the time of healing between the two groups. (p value = 0.918). Hence, this study does not suggest that collagen cross linking adds any benefit to the time taken to for fungal corneal ulcers to heal. CONCLUSION: 1.Collagen crosslinking has no benefit in reducing the time of healing of ulcers. 2.CXL does not reduce or increase the failure rate of corneal ulcers. 3. There was no correlation between size of ulcer/diabetic status/type of organism and the outcome of corneal ulcer treatment with CXL compared to controls

Collaborative adaptive exponential linear-in-the-parameters nonlinear filters

by Vinal Patel, Somanath Pradhan and Nithin V. Georg

Car Cabin Co2, A Safety Issue

Indoor Air Quality has become an important human health and safety concern, clean air is essential for good health. Many studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO2) accumulation which can potentially lead to deleterious effects on cognitive function. It is known that in-vehicle CO2 concentration tends to increase due to occupant exhalation when the HVAC (Heating, Ventilation and Air Conditioning) air is in recirculation mode. This study establishes a major safety problem associated with automotive; Field experiments were conducted to measure CO2 concentration in a typical automotive cabin

RNA-Puzzles Round V: blind predictions of 23 RNA structures

RNA-Puzzles is a collective endeavor dedicated to the advancement and improvement of RNA three-dimensional structure prediction. With agreement from structural biologists, RNA structures are predicted by modeling groups before publication of the experimental structures. We report a large-scale set of predictions by 18 groups for 23 RNA-Puzzles: 4 RNA elements, 2 Aptamers, 4 Viral elements, 5 Ribozymes and 8 Riboswitches. We describe automatic assessment protocols for comparisons between prediction and experiment. Our analyses reveal some critical steps to be overcome to achieve good accuracy in modeling RNA structures: identification of helix-forming pairs and of non-Watson-Crick modules, correct coaxial stacking between helices and avoidance of entanglements. Three of the top four modeling groups in this round also ranked among the top four in the CASP15 contest

Global burden of cardiovascular diseases and risk factors, 1990-2019 : Update from the GBD 2019 Study

Cardiovascular diseases (CVDs), principally ischemic heart disease (IHD) and stroke, are the leading cause of global mortality and a major contributor to disability. This paper reviews the magnitude of total CVD burden, including 13 underlying causes of cardiovascular death and 9 related risk factors, using estimates from the Global Burden of Disease (GBD) Study 2019. GBD, an ongoing multinational collaboration to provide comparable and consistent estimates of population health over time, used all available population-level data sources on incidence, prevalence, case fatality, mortality, and health risks to produce estimates for 204 countries and territories from 1990 to 2019. Prevalent cases of total CVD nearly doubled from 271 million (95% uncertainty interval [UI]: 257 to 285 million) in 1990 to 523 million (95% UI: 497 to 550 million) in 2019, and the number of CVD deaths steadily increased from 12.1 million (95% UI:11.4 to 12.6 million) in 1990, reaching 18.6 million (95% UI: 17.1 to 19.7 million) in 2019. The global trends for disability-adjusted life years (DALYs) and years of life lost also increased significantly, and years lived with disability doubled from 17.7 million (95% UI: 12.9 to 22.5 million) to 34.4 million (95% UI:24.9 to 43.6 million) over that period. The total number of DALYs due to IHD has risen steadily since 1990, reaching 182 million (95% UI: 170 to 194 million) DALYs, 9.14 million (95% UI: 8.40 to 9.74 million) deaths in the year 2019, and 197 million (95% UI: 178 to 220 million) prevalent cases of IHD in 2019. The total number of DALYs due to stroke has risen steadily since 1990, reaching 143 million (95% UI: 133 to 153 million) DALYs, 6.55 million (95% UI: 6.00 to 7.02 million) deaths in the year 2019, and 101 million (95% UI: 93.2 to 111 million) prevalent cases of stroke in 2019. Cardiovascular diseases remain the leading cause of disease burden in the world. CVD burden continues its decades-long rise for almost all countries outside high-income countries, and alarmingly, the age-standardized rate of CVD has begun to rise in some locations where it was previously declining in high-income countries. There is an urgent need to focus on implementing existing cost-effective policies and interventions if the world is to meet the targets for Sustainable Development Goal 3 and achieve a 30% reduction in premature mortality due to noncommunicable diseases

Population-level risks of alcohol consumption by amount, geography, age, sex, and year: a systematic analysis for the Global Burden of Disease Study 2020

BACKGROUND: The health risks associated with moderate alcohol consumption continue to be debated. Small amounts of alcohol might lower the risk of some health outcomes but increase the risk of others, suggesting that the overall risk depends, in part, on background disease rates, which vary by region, age, sex, and year. METHODS: For this analysis, we constructed burden-weighted dose-response relative risk curves across 22 health outcomes to estimate the theoretical minimum risk exposure level (TMREL) and non-drinker equivalence (NDE), the consumption level at which the health risk is equivalent to that of a non-drinker, using disease rates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020 for 21 regions, including 204 countries and territories, by 5-year age group, sex, and year for individuals aged 15-95 years and older from 1990 to 2020. Based on the NDE, we quantified the population consuming harmful amounts of alcohol. FINDINGS: The burden-weighted relative risk curves for alcohol use varied by region and age. Among individuals aged 15-39 years in 2020, the TMREL varied between 0 (95% uncertainty interval 0-0) and 0·603 (0·400-1·00) standard drinks per day, and the NDE varied between 0·002 (0-0) and 1·75 (0·698-4·30) standard drinks per day. Among individuals aged 40 years and older, the burden-weighted relative risk curve was J-shaped for all regions, with a 2020 TMREL that ranged from 0·114 (0-0·403) to 1·87 (0·500-3·30) standard drinks per day and an NDE that ranged between 0·193 (0-0·900) and 6·94 (3·40-8·30) standard drinks per day. Among individuals consuming harmful amounts of alcohol in 2020, 59·1% (54·3-65·4) were aged 15-39 years and 76·9% (73·0-81·3) were male. INTERPRETATION: There is strong evidence to support recommendations on alcohol consumption varying by age and location. Stronger interventions, particularly those tailored towards younger individuals, are needed to reduce the substantial global health loss attributable to alcohol. FUNDING: Bill & Melinda Gates Foundation

Global estimates on the number of people blind or visually impaired by cataract: a meta-analysis from 2000 to 2020

Background: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by cataract and their proportion of the total number of vision-impaired individuals. Methods: A systematic review and meta-analysis of published population studies and gray literature from 2000 to 2020 was carried out to estimate global and regional trends. We developed prevalence estimates based on modeled distance visual impairment and blindness due to cataract, producing location-, year-, age-, and sex-specific estimates of moderate to severe vision impairment (MSVI presenting visual acuity &lt;6/18, ≥3/60) and blindness (presenting visual acuity &lt;3/60). Estimates are age-standardized using the GBD standard population. Results: In 2020, among overall (all ages) 43.3 million blind and 295 million with MSVI, 17.0 million (39.6%) people were blind and 83.5 million (28.3%) had MSVI due to cataract blind 60% female, MSVI 59% female. From 1990 to 2020, the count of persons blind (MSVI) due to cataract increased by 29.7%(93.1%) whereas the age-standardized global prevalence of cataract-related blindness improved by −27.5% and MSVI increased by 7.2%. The contribution of cataract to the age-standardized prevalence of blindness exceeded the global figure only in South Asia (62.9%) and Southeast Asia and Oceania (47.9%). Conclusions: The number of people blind and with MSVI due to cataract has risen over the past 30 years, despite a decrease in the age-standardized prevalence of cataract. This indicates that cataract treatment programs have been beneficial, but population growth and aging have outpaced their impact. Growing numbers of cataract blind indicate that more, better-directed, resources are needed to increase global capacity for cataract surgery.</p