System-Scenario Methodology to Design a Highly Reliable Radiation-Hardened Memory for Space Applications

Cache memory circuits are one of the concerns of computing systems, especially in terms of power consumption, reliability, and high performance. Voltage-scaling techniques can be used to reduce the total power consumption of the caches. However, aggressive voltage scaling significantly increases the probability of memory failure, especially in environments with high radiation levels, such as space. It is, therefore, important to deploy techniques to deal with reliability issues along with voltage scaling. In this chapter, we present a system-scenario methodology for radiation-hardened memory design to keep the reliability during voltage scaling. Although any SRAM array can benefit from the design, we frame our study on the recently proposed radiation-hardened cell, Nwise, which provides high level of tolerance against single event and multi event upsets in memories. To reduce the power consumption while upholding reliability, we leverage the system-scenario-based design methodology to optimize the energy consumption in applications, where system requirements vary dynamically at run time. We demonstrate the use of the methodology with a use case related to satellite systems and solar activity. Our simulations show that we achieve up to 49.3% power consumption saving compared to using a cache design with a fixed nominal power supply level

An Energy-Efficient Design Paradigm for a Memory Cell Based on Novel Nanoelectromechanical Switches

In this chapter, we explain NEMsCAM cell, a new content-addressable memory (CAM) cell, which is designed based on both CMOS technologies and nanoelectromechanical (NEM) switches. The memory part of NEMsCAM is designed with two complementary nonvolatile NEM switches and located on top of the CMOS-based comparison component. As a use case, we evaluate first-level instruction and data translation lookaside buffers (TLBs) with 16 nm CMOS technology at 2 GHz. The simulation results demonstrate that the NEMsCAM TLB reduces the energy consumption per search operation (by 27%), standby mode (by 53.9%), write operation (by 41.9%), and the area (by 40.5%) compared to a CMOS-only TLB with minimal performance overhead

NEMsCAM: A novel CAM cell based on nano-electro-mechanical switch and CMOS for energy efficient TLBs

In this paper we propose a novel Content Addressable Memory (CAM) cell, NEMsCAM, based on both Nano-electro-mechanical (NEM) switches and CMOS technologies. The memory component of the proposed CAM cell is designed with two complementary non-volatile NEM switches and located on top of the CMOS-based comparison component. As a use case for the NEMsCAM cell, we design first-level data and instruction Translation Lookaside Buffers (TLBs) with 16nm CMOS technology at 2GHz. The simulations show that the NEMsCAM TLB reduces the energy consumption per search operation (by 27%), write operation (by 41.9%) and standby mode (by 53.9%), and the area (by 40.5%) compared to a CMOS-only TLB with minimal performance overhead.We thank all anonymous reviewers for their insightful comments. This work is supported in part by the European Union (FEDER funds) under contract TIN2012-34557, and the European Union’s Seventh Framework Programme (FP7/2007-2013) under the ParaDIME project (GA no. 318693)Postprint (author's final draft

Circuit design of a dual-versioning L1 data cache for optimistic concurrency

This paper proposes a novel L1 data cache design with dual-versioning SRAM cells (dvSRAM) for chip multi-processors (CMP) that implement optimistic concurrency proposals. In this new cache architecture, each dvSRAM cell has two cells, a main cell and a secondary cell, which keep two versions of the same data. These values can be accessed, modified, moved back and forth between the main and secondary cells within the access time of the cache. We design and simulate a 32-KB dual-versioning L1 data cache with 45nm CMOS technology at 2GHz processor frequency and 1V supply voltage, which we describe in detail. We also introduce three well-known use cases that make use of optimistic concurrency execution and that can benefit from our proposed design. Moreover, we evaluate one of the use cases to show the impact of the dual-versioning cell in both performance and energy consumption. Our experiments show that large speedups can be achieved with acceptable overall energy dissipation.Postprint (published version

Nwise: an Area Efficient and Highly Reliable Radiation Hardened Memory Cell Designed for Space Applications

In the electronics space industry, memory cells are one of the main concerns, especially in term of reliability, since radiation particles may hit cell nodes and disturb the state of the cell, possibly causing fatal errors. In this paper we propose the Nwise SRAM cell, an area-efficient and highly reliable radiation hardened memory cell for use in high-density memories for space applications. Simulations confirm that the proposed Nwise cell is fully tolerant to single event upsets (SEU) in any one of its nodes regardless of upset polarity. Meanwhile, compared with the RHBD-10T cell, the latest area-efficient radiation hardened memory cell, it has higher robustness: the minimum critical charge of Nwise is 4.1× higher than the minimum critical charge of the RHBD-10T cell. It also shows 23% and 12% improvements in read and write static noise margin (SNM). Furthermore, compared with RHBD-10T, up to 18.4% and 7.0% power savings are obtainable during write and read operations respectively. Nwise is about 2.28× faster than RHBD-10T during the more frequent read operation, with a similar penalty in write time. Finally, Nwise is the first proposed high density and reliable radiation hardened memory cell that has been designed using the 28nm FD-SOI technology node. Index Terms—space applications, radiation hardening, single event upset (SEU), multiple event upset (MEU), SRAM design, 28nm FD-SOI, reliability, soft errors, Nwise cel

Circuit design of a dual-versioning L1 data cache

This paper proposes a novel L1 data cache design with dual-versioning SRAM cells (dvSRAM) for chip multi-processors that implement optimistic concurrency proposals. In this cache architecture, each dvSRAM cell has two cells, a main cell and a secondary cell, which keep two versions of the same logical data. These values can be accessed, modified, moved back and forth between the main and secondary cells within the access time of the cache. We design and simulate a 32 KB dual-versioning L1 data cache and introduce three well-known use cases that make use of optimistic concurrency execution that can benefit from our proposed design. © 2011 Elsevier B.V. All rights reserved.This work is supported by the cooperation agreement between the Barcelona Supercomputing Center and Microsoft Research, by the Ministry of Science and Technology of Spain and the European Union (FEDER funds) under contracts TIN2007-60625 and TIN2008-02055-E, by the European Network of Excellence on High-Performance Embedded Architecture and Compilation (HiPEAC) and by the European Commission FP7 project VELOX (216852).Peer Reviewe

Comparison of insulin resistance indices in predicting albuminuria among patients with type 2 diabetes

Abstract Purpose Diabetes is the leading cause of kidney disease. Up to 40% of the population with diabetes experience diabetic kidney disease (DKD). The correlation of DKD with insulin resistance (IR) indices has been shown in previous studies. In this study, the objective was to evaluate surrogate IR indices, including the Triglyceride-Glucose (TyG) index, Visceral Adiposity Index (VAI), Lipid Accumulation Product (LAP), and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) to find the most valuable index for the correlation between albuminuria and IR in the type 2 diabetes (T2D) population. Albuminuria is defined as urine albumin excretion of > 30 mg/day. Methods In this cross-sectional study, 2934 participants were enrolled and evaluated for urinary albumin excretion, and albuminuria was detected in 526 of the entries. The logistic regression models and Receiver Operating Characteristic (ROC) curve analysis were performed to assess the relationship of TyG index, VAI, LAP, and HOMA-IR's with albuminuria in patients with T2D. Results The TyG index had the highest association (OR 1.67) with the presence of albuminuria in patients with T2D, followed by HOMA-IR (OR 1.127), VAI (OR 1.028), and LAP (OR 1.004). These four indices remained independent after adjustment for multiple confounders. Based on the ROC curve, TyG revealed the best area under the curve (AUC) for revealing albuminuria with sufficient accuracy (AUC: 0.62) in comparison with other measured indices. The calculated TyG index cut-off point for the presence of albuminuria was 9.39. Conclusion Among the indices, TyG index had the most significant correlation with albuminuria in patients with T2D

The Effectiveness of a Radiation Safety Training Program in Increasing the Radiation Safety Knowledge of Physicians: A Pilot Study

Background Ionizing and non-ionizing radiation are widely used in the diagnosis and treatment of diseases. Considering the potential risks of radiation, radiation safety training courses are important for medical staff. Objective The aim of this study was to investigate the effectiveness of one-day radiation safety training program in increasing the radiation safety knowledge of physicians. Methods In this descriptive-analytical study, subjects were 12 physicians (6 general practitioners and 6 nonradiologist specialists) participated in the training program organized by Qazvin University of Medical Sciences in 2018. A researcher-made questionnaire was used for surveying physicians before and after the training. The mean and standard deviation of the scores were first calculated. Then, the pre- and post-test scores were compared using Wilcoxon signed-rank test, and the correlation of these scores with their age, gender, expertise area, and work experience was examined by Spearman's correlation test. Findings The mean total scores of the physicians before and after training were 7.00±2.56 (ranged 3-11) and 11.92± 2.31 (ranged 8-15) out of 18, respectively. The radiation safety knowledge of physicians significantly increased after training (P<0.001). No significant relationship was found between their scores and their age, gender, expertise area and work experience. Conclusion The radiation safety training program was effective in increasing the radiation safety knowledge of physicians and it can be used for a larger community of physicians

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

BackgroundEstimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period.Methods22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution.FindingsGlobal all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations.InterpretationGlobal adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic