18 research outputs found

    Designing energy-efficient sub-threshold logic circuits using equalization and non-volatile memory circuits using memristors

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    The very large scale integration (VLSI) community has utilized aggressive complementary metal-oxide semiconductor (CMOS) technology scaling to meet the ever-increasing performance requirements of computing systems. However, as we enter the nanoscale regime, the prevalent process variation effects degrade the CMOS device reliability. Hence, it is increasingly essential to explore emerging technologies which are compatible with the conventional CMOS process for designing highly-dense memory/logic circuits. Memristor technology is being explored as a potential candidate in designing non-volatile memory arrays and logic circuits with high density, low latency and small energy consumption. In this thesis, we present the detailed functionality of multi-bit 1-Transistor 1-memRistor (1T1R) cell-based memory arrays. We present the performance and energy models for an individual 1T1R memory cell and the memory array as a whole. We have considered TiO2- and HfOx-based memristors, and for these technologies there is a sub-10% difference between energy and performance computed using our models and HSPICE simulations. Using a performance-driven design approach, the energy-optimized TiO2-based RRAM array consumes the least write energy (4.06 pJ/bit) and read energy (188 fJ/bit) when storing 3 bits/cell for 100 nsec write and 1 nsec read access times. Similarly, HfOx-based RRAM array consumes the least write energy (365 fJ/bit) and read energy (173 fJ/bit) when storing 3 bits/cell for 1 nsec write and 200 nsec read access times. On the logic side, we investigate the use of equalization techniques to improve the energy efficiency of digital sequential logic circuits in sub-threshold regime. We first propose the use of a variable threshold feedback equalizer circuit with combinational logic blocks to mitigate the timing errors in digital logic designed in sub-threshold regime. This mitigation of timing errors can be leveraged to reduce the dominant leakage energy by scaling supply voltage or decreasing the propagation delay. At the fixed supply voltage, we can decrease the propagation delay of the critical path in a combinational logic block using equalizer circuits and, correspondingly decrease the leakage energy consumption. For a 8-bit carry lookahead adder designed in UMC 130 nm process, the operating frequency can be increased by 22.87% (on average), while reducing the leakage energy by 22.6% (on average) in the sub-threshold regime. Overall, the feedback equalization technique provides up to 35.4% lower energy-delay product compared to the conventional non-equalized logic. We also propose a tunable adaptive feedback equalizer circuit that can be used with sequential digital logic to mitigate the process variation effects and reduce the dominant leakage energy component in sub-threshold digital logic circuits. For a 64-bit adder designed in 130 nm our proposed approach can reduce the normalized delay variation of the critical path delay from 16.1% to 11.4% while reducing the energy-delay product by 25.83% at minimum energy supply voltage. In addition, we present detailed energy-performance models of the adaptive feedback equalizer circuit. This work serves as a foundation for the design of robust, energy-efficient digital logic circuits in sub-threshold regime

    Rapid mapping of digital integrated circuit logic gates via multi-spectral backside imaging

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    Modern semiconductor integrated circuits are increasingly fabricated at untrusted third party foundries. There now exist myriad security threats of malicious tampering at the hardware level and hence a clear and pressing need for new tools that enable rapid, robust and low-cost validation of circuit layouts. Optical backside imaging offers an attractive platform, but its limited resolution and throughput cannot cope with the nanoscale sizes of modern circuitry and the need to image over a large area. We propose and demonstrate a multi-spectral imaging approach to overcome these obstacles by identifying key circuit elements on the basis of their spectral response. This obviates the need to directly image the nanoscale components that define them, thereby relaxing resolution and spatial sampling requirements by 1 and 2 - 4 orders of magnitude respectively. Our results directly address critical security needs in the integrated circuit supply chain and highlight the potential of spectroscopic techniques to address fundamental resolution obstacles caused by the need to image ever shrinking feature sizes in semiconductor integrated circuits

    Effects of famotidine and vitamin C on low dose radiation-induced micronuclei in mice bone marrow cells

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         The radioprotective effects of vitamin C and famotidine were investigated using the micronucleus test for anticlastogenic and cell proliferation activity. Various doses of vitamin C and famotidine were administered intraperitoneally 2 h before 2Gy gamma irradiation to NMRI adult male mice. Frequency of micronuclei in 1000 PCEs (MnPCEs) were scored for each sample. Cell proliferation ratio (PCE/PCE+NCE) was also calculated. Data were statistically evaluated using one-way ANOVA and Tukey’s HSD test. The results indicated that gamma irradiation alone caused a significant increase in the MnPCEs and reduced the cell proliferation ratio. Administration of various doses of famotidine and vitamin C before gamma irradiation reduced MnPCEs and therefore clastogenic effects of radiation. Famotidine didn’t change cell proliferation compared to the irradiation group but vitamin C significantly improved and increased cell proliferation to the control group’s level. The dose reduction factor (DRF) calculated, shows a DRF=2 for famotidine and a DRF=1.7 for vitamin C which is indicative of a high radioprotective property of these compounds. The way in which these compounds reduced the clastogenic effects of radiation might be via antioxidant property and free radical scavenging mechanism

    Mapping 123 million neonatal, infant and child deaths between 2000 and 2017

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    Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations

    Global, regional, and national cancer incidence, mortality, years of life lost, years lived with disability, and disability-Adjusted life-years for 29 cancer groups, 1990 to 2017 : A systematic analysis for the global burden of disease study

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    Importance: Cancer and other noncommunicable diseases (NCDs) are now widely recognized as a threat to global development. The latest United Nations high-level meeting on NCDs reaffirmed this observation and also highlighted the slow progress in meeting the 2011 Political Declaration on the Prevention and Control of Noncommunicable Diseases and the third Sustainable Development Goal. Lack of situational analyses, priority setting, and budgeting have been identified as major obstacles in achieving these goals. All of these have in common that they require information on the local cancer epidemiology. The Global Burden of Disease (GBD) study is uniquely poised to provide these crucial data. Objective: To describe cancer burden for 29 cancer groups in 195 countries from 1990 through 2017 to provide data needed for cancer control planning. Evidence Review: We used the GBD study estimation methods to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-Adjusted life-years (DALYs). Results are presented at the national level as well as by Socio-demographic Index (SDI), a composite indicator of income, educational attainment, and total fertility rate. We also analyzed the influence of the epidemiological vs the demographic transition on cancer incidence. Findings: In 2017, there were 24.5 million incident cancer cases worldwide (16.8 million without nonmelanoma skin cancer [NMSC]) and 9.6 million cancer deaths. The majority of cancer DALYs came from years of life lost (97%), and only 3% came from years lived with disability. The odds of developing cancer were the lowest in the low SDI quintile (1 in 7) and the highest in the high SDI quintile (1 in 2) for both sexes. In 2017, the most common incident cancers in men were NMSC (4.3 million incident cases); tracheal, bronchus, and lung (TBL) cancer (1.5 million incident cases); and prostate cancer (1.3 million incident cases). The most common causes of cancer deaths and DALYs for men were TBL cancer (1.3 million deaths and 28.4 million DALYs), liver cancer (572000 deaths and 15.2 million DALYs), and stomach cancer (542000 deaths and 12.2 million DALYs). For women in 2017, the most common incident cancers were NMSC (3.3 million incident cases), breast cancer (1.9 million incident cases), and colorectal cancer (819000 incident cases). The leading causes of cancer deaths and DALYs for women were breast cancer (601000 deaths and 17.4 million DALYs), TBL cancer (596000 deaths and 12.6 million DALYs), and colorectal cancer (414000 deaths and 8.3 million DALYs). Conclusions and Relevance: The national epidemiological profiles of cancer burden in the GBD study show large heterogeneities, which are a reflection of different exposures to risk factors, economic settings, lifestyles, and access to care and screening. The GBD study can be used by policy makers and other stakeholders to develop and improve national and local cancer control in order to achieve the global targets and improve equity in cancer care. © 2019 American Medical Association. All rights reserved.Peer reviewe

    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

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    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

    Designing a Quality Assessment Model with Academic Entrepreneurship Development Approach

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    This study aims at designing a quality assessment model with academic entrepreneurship development approach.The mixed method (qualitative/descriptive Grounded Theory and quantitative / descriptive-correlational) is used to do this research. Its statistical population in qualitative section included 12 experts in entrepreneurship field selected by snowball method and they participated in data collection by deep interviewing tool until reaching the theoretical saturation level. The statistical society in its quantitative part includes professors and experts in entrepreneurship field at public universities of Tehran in academic year of 2017-18. The statistical sample is determined using Cochran formula, and 113 researcher-made questionnaires are distributed to collect data. The research validity and reliability in quantitative and qualitative sections are confirmed. To analyze data, coding method (open, axial, and selective coders) is used in qualitative, and the structural equation method in quantitative section. The research results reveal that quality assessment in universities may be investigated in two categories of internal factors(educational content, entrepreneurial leadership, human resources, educational justice, quality of evaluation, performance feedback, quality of information technology, quality of physical space) and external factors(Economic factors, social factors, cultural factors, geographical factors) to be examined and influenced.Furthermore, the quality assessment of universities for the academic entrepreneurship development have implications (commercialization, accountability, entrepreneurial skills development, value creation, and economic development)

    Evaluation of the Aging Effect on the Microstructure of Co-28Cr-6Mo-0.3C Alloy: Experimental Characterization and Computational Thermodynamics

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    In the current research, we studied the role of the solution treatment and aging on the microstructure of a Co−28Cr−5Mo−0.3C alloy. We used metallographic observations, scanning electron microscopy (SEM), and hardness measurements for the evaluations. We also made a comparison between the phase equilibrium calculated with Thermo-Calc, using TCFE8 and TCNI8 thermodynamic databases and experimental findings. The experimental results showed that the transformation of the metastable FCC phase to the HCP phase during aging was extremely sensitive to the solution treatment prior to aging. The effect of the increase in the solution temperature and time was detectable through promotion of the martensitic transformation during quenching in which HCP1 (straight bands) and HCP2 (lamellar-type constitution) phases had developed. In contrast, a low solution temperature and time caused most of the primary carbides to remain in an undissolved condition in the matrix; therefore, during aging, no sign of the FCC to HCP1 (straight bands) phase transformation could be observed. However, we observed the formation of the HCP2 phase (lamellar-type constitution) at the grain boundaries. In addition, the X-ray diffraction pattern indicated that the sample solution treated at lower temperatures and shorter times had a stronger martensitic transformation during aging compared to the sample solution treated at higher temperatures and longer times. Hardness measurements confirmed the results. Thermodynamical calculations showed that an agreement existed between the experiments and calculations. We also discuss the results from the TCFE8 and TCNI8 databases

    Interrelationship between underprivileged neighborhoods and health promotion lifestyles: insights from Kermanshah, Iran

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    Aim: Iran is facing the consequences of the hubristic period and the level of mortalities is affected by lifestyles. Residents of underprivileged neighborhoods of the Iranian Kermanshah Metropolis encounter numerous socioeconomic, physical, and cultural challenges. Hence, this study aims to investigate the ecocultural and physical conditions of underprivileged neighborhoods and their effects on the residents’ health promotion lifestyles in the neighborhoods in Kermanshah Metropolis, Western Iran. Subjects and methods: In this cross-sectional study, the statistical population included the underprivileged neighborhoods of the Kermanshah Metropolis. The ecocultural and physical conditions of these neighborhoods were assessed using the population and housing census data, and lifestyle was measured using the Health Promoting Lifestyle Profile II (HPLP II). As for data analysis, the descriptive statistics analysis of variance (ANOVA) and the Pearson correlation coefficient were employed in SPSS v.21. Results: The results of the present study revealed that the total mean score of lifestyles in underprivileged neighborhoods was low (111.67 ± 23.59). It was shown that females had a better quality of life than males, and the highest and lowest mean scores belonged to interpersonal relations and physical activity, respectively. Comparison of the findings also indicated that the underprivileged neighborhoods were significantly different in terms of health promotion lifestyles. As for the economic, physical, and cultural indexes, it was demonstrated that only cultural indices were significantly correlated with health promotion lifestyles, with a correlation coefficient of 0.716. The negative correlation coefficient of the young population was indicative of the inverse relationship between the growth of the young population and health promotion lifestyles. A negative relationship was also observed between nutrition and the young population. It was also shown that interpersonal relations negatively and positively correlated with the young population and migration rate, respectively. Conclusion: The findings of this study revealed the urgent need for attention and emphasis to be given to the planning of activities to improve residents’ conditions of health promotion lifestyle in underprivileged neighborhoods by the urban managers and policymakers in the health and associated fields.</p

    Detecting Hardware Trojans Using Backside Optical Imaging of Embedded Watermarks

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    ABSTRACT Hardware Trojans are a critical security threat to integrated circuits. We propose an optical method to detect and localize Trojans inserted during the chip fabrication stage. We engineer the fill cells in a standard cell library to be highly reflective at near-IR wavelengths so that they can be readily observed in an optical image taken through the backside of the chip. The pattern produced by their locations produces an easily measured watermark of the circuit layout. Replacement, modification or re-arrangement of these cells to add a Trojan can therefore be detected through rapid postfabrication backside imaging. We evaluate our approach using various hardware blocks where the Trojan circuit area is less than 0.1% of the total area and it consumes less than 2% leakage power of the entire chip. In addition, we evaluate the tolerance of our methodology to background measurement noise and process variation
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