25 research outputs found
An area-optimized N-bit multiplication technique using N/2-bit multiplication algorithm
A unique design for an optimized N-bit multiplier is proposed and implemented which utilizes a modified divide-and-conquer technique. The conventional technique requires four N/2-bit multipliers to perform N-bit multiplication, whereas the proposed design uses only one multiplier module in hardware to perform the functionality of four modules. It uses Dadda algorithm in its multiplier module. It has been implemented using Verilog HDL, and a good accuracy of results was observed in simulations which effectively verify its functionality. Design was also synthesized on various FPGAs including Spartan 3E, Virtex-5 and Virtex-7. Performance summary, after place and route, showed that the proposed approach significantly reduces hardware utilization. Furthermore, the proposed design is almost 75% more efficient in terms of resources utilization and operating frequency as compared to the conventional design
Association Of Maternal Age And Hemoglobin Level With Apgar Score Of Newborns In A Tertiary Care Hospital Of Suburbs Of Islamabad
Objectives: To determine the association of Apgar score with maternal age and hemoglobin.
Methods
A cross-sectional study was conducted on mothers (n=306) delivering live, full-term, singleton babies by spontaneous vertex delivery. Women who suffered stillbirths had babies of unknown gestational age or showed co-morbidities were excluded.
SPSS version 26 was used for data analysis. Mean + standard deviation, and percentages were calculated. Cross-tabulation and logistic regression were done to see the association between dependent and independent variables. A p-value of <0.05 was statistically significant.
Results
The ages of women ranged from 20 to 40 years (mean= 25+1.9). The number of patients aged 24 years with Hb <7g/dl was 6 (37.5%). Out of all, 90 (29.4%) patients had Hb >11g/dl, and their ages were 30 years which was significant (p = 0.000). Apgar score for the neonates showed that 258 (84.3%) had an Apgar score >7 while 48 (15.7%) had a score < 7. Babies of mothers whose age was 26 years had Apgar score < 7(25%) (p = 0.001). Neonatal birth weight, of <2kg was observed in infants born to young mothers of 26 years of age (20%) (p = 0.001), and a weight >3.5kg was recorded in 20 infants (6.5%). The younger mothers had lower Hb, and their babies had low Apgar scores <7 at the time of birth (p = 0.001).
Conclusion
Women of younger age and lower hemoglobin levels give birth to infants with low Apgar scores and birth weight. Low birth weight in neonates is significantly associated with a low five-minute Apgar score
Verification of Tether Deployment System aboard CubeSat through Dynamics Simulations and Tests
This paper proposes a proper model selection strategies for the dynamic simulations of the tether deployment mission aboard a CubeSat. Space tether technology will enable innovative space missions in the near future. The Coulomb Drag Propulsion (CDP), including electric solar wind sailing, is one of the plausible future technologies. The authors currently develop a CubeSat, FORESAIL-1, for space demonstration of CDP. However, the analytical simulations for the verification and validation of the mission design typically require a high computational cost. This is because a minimum model order is not selected properly. In this study, through observing a preliminary analytical model for tether deployment analysis, the simplest model is chosen to avoid the mission failure modes in each deployment phase.Peer reviewe
Artificial Intelligence for Cognitive Health Assessment: State-of-the-Art, Open Challenges and Future Directions
The subjectivity and inaccuracy of in-clinic Cognitive Health Assessments (CHA) have led many researchers to explore ways to automate the process to make it more objective and to facilitate the needs of the healthcare industry. Artificial Intelligence (AI) and machine learning (ML) have emerged as the most promising approaches to automate the CHA process. In this paper, we explore the background of CHA and delve into the extensive research recently undertaken in this domain to provide a comprehensive survey of the state-of-the-art. In particular, a careful selection of significant works published in the literature is reviewed to elaborate a range of enabling technologies and AI/ML techniques used for CHA, including conventional supervised and unsupervised machine learning, deep learning, reinforcement learning, natural language processing, and image processing techniques. Furthermore, we provide an overview of various means of data acquisition and the benchmark datasets. Finally, we discuss open issues and challenges in using AI and ML for CHA along with some possible solutions. In summary, this paper presents CHA tools, lists various data acquisition methods for CHA, provides technological advancements, presents the usage of AI for CHA, and open issues, challenges in the CHA domain. We hope this first-of-its-kind survey paper will significantly contribute to identifying research gaps in the complex and rapidly evolving interdisciplinary mental health field
Coulomb drag propulsion experiments of ESTCube-2 and FORESAIL-1
This paper presents two technology experiments – the plasma brake for deorbiting and the electric solar wind sail for interplanetary propulsion – on board the ESTCube-2 and FORESAIL-1 satellites. Since both technologies employ the Coulomb interaction between a charged tether and a plasma flow, they are commonly referred to as Coulomb drag propulsion. The plasma brake operates in the ionosphere, where a negatively charged tether deorbits a satellite. The electric sail operates in the solar wind, where a positively charged tether propels a spacecraft, while an electron emitter removes trapped electrons. Both satellites will be launched in low Earth orbit carrying nearly identical Coulomb drag propulsion experiments, with the main difference being that ESTCube-2 has an electron emitter and it can operate in the positive mode. While solar-wind sailing is not possible in low Earth orbit, ESTCube-2 will space-qualify the components necessary for future electric sail experiments in its authentic environment. The plasma brake can be used on a range of satellite mass classes and orbits. On nanosatellites, the plasma brake is an enabler of deorbiting – a 300-m-long tether fits within half a cubesat unit, and, when charged with -1 kV, can deorbit a 4.5-kg satellite from between a 700- and 500-km altitude in approximately 9–13 months. This paper provides the design and detailed analysis of low-Earth-orbit experiments, as well as the overall mission design of ESTCube-2 and FORESAIL-1.Peer reviewe
Coulomb drag propulsion experiments of ESTCube-2 and FORESAIL-1
This paper presents two technology experiments – the plasma brake for deorbiting and the electric solar wind sail for interplanetary propulsion – on board the ESTCube-2 and FORESAIL-1 satellites. Since both technologies employ the Coulomb interaction between a charged tether and a plasma flow, they are commonly referred to as Coulomb drag propulsion. The plasma brake operates in the ionosphere, where a negatively charged tether deorbits a satellite. The electric sail operates in the solar wind, where a positively charged tether propels a spacecraft, while an electron emitter removes trapped electrons. Both satellites will be launched in low Earth orbit carrying nearly identical Coulomb drag propulsion experiments, with the main difference being that ESTCube-2 has an electron emitter and it can operate in the positive mode. While solar-wind sailing is not possible in low Earth orbit, ESTCube-2 will space-qualify the components necessary for future electric sail experiments in its authentic environment. The plasma brake can be used on a range of satellite mass classes and orbits. On nanosatellites, the plasma brake is an enabler of deorbiting – a 300-m-long tether fits within half a cubesat unit, and, when charged with - 1 kV, can deorbit a 4.5-kg satellite from between a 700- and 500-km altitude in approximately 9–13 months. This paper provides the design and detailed analysis of low-Earth-orbit experiments, as well as the overall mission design of ESTCube-2 and FORESAIL-1.</p
Recommended from our members
Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed
Onboard Communication Systems for Low Cost Small Satellites
The development of a large number of Nano and Pico-satellite missions, with spacecrafts of mass lower than 10 kg and 1 kg respectively, started in the beginning of this century due to the availability of low-cost piggyback launch opportunities. Such small satellites are usually built using commercially available electronic components that are not qualified for the space environment. This approach reduces the total cost of the satellite missions but at the expense of design effort which is needed not to compromise the reliability of the designed spacecrafts. One of the foremost design efforts in this regard is the design re-use method which extends the cost reduction to
the system level, and helps in simplifying the development cycle for a space mission. The on-board communication subsystem consist of critical set of elements common to every mission, and therefore is not exempt from such a design philosophy. The on-board networks, on-board transceivers, and the protocols are all critical elements for a spacecraft mission and, at the same time, some of the most specialized and complex ones. Innovative data communication systems are therefore desirable for the future space missions.
The size of the satellites keeps reducing as the time progresses, therefore the harness mass and complexity inside the satellite becomes a prime challenge. An innovative approach to smart harness is therefore necessary which reduces the wiring harness for intra-satellite communication.
This thesis copes with several problems related to spacecraft subsystem development, integration and testing and proposes some solutions that can help in both keeping system development and production cost low while still achieving good performances.
Chapter 1 starts with the design goals of the work and introduction to the Modular Architecture of Small Satellites (AraMiS) project. The biggest design goals of space systems of current era are the cost, time and complexity issues. Modularity
and cost-sharing between multiple missions will appear as optimal solutions for reducing development costs, while the use of commercial components (COTS) will be presented as a way to simplify procurement and further lower system cost
In Chapter 2, the smart harness approach is proposed which reduces the traditional harness complexities inside the small spacecrafts. The chapter focuses on the design of small spacecrafts which are completely modular and flexible. Modularity at mechanical, electrical and testing level will be discussed in this chapter.
Chapter 3 addresses the complete life cycle of a subsystem module i.e. from conception to the final design and testing. The module life cycle uses a variety of Unified Modelling Language (UML) diagrams to fulfill different design stages.
Chapter 4 proposes different types of spacecraft configurations based on smart harness approaches including physical module based, satellite on demand and reusable design configurations.A design trade-off is also performed for these configurations.
Chapter 6 proposes the design technique of physical module based spacecraft configuration which is based on physical plug and play connectors and logical slots for the subsystem modules. A honeycomb based tile is discussed in this chapter
which is used for larger and more demanding spacecraft structures.
In Chapter 7, the requirement of data communication across different subsystems of the spacecrafts are described. The use cases have been discussed and the implementation rules have been defined in this Chapter.
Chapters 8,9 and 10 focus on module design for intra-satellite communication purposes. The modules have been designed for wired as well as wireless data communication. The wired solution is based on on-board data bus module for inter-tile
data communication. Wireless solutions included both optical and radio frequency
based solutions. The optical module has been designed for optical free space as well as glass fiber based communication purposes. The comparison between theoretical and practical results has been made. The radio frequency based module is based on commercial module and simpliciTI protocol stack.
In Chapter 11, the functional testing of modules, tiles and whole satellites is discussed. The testing scheme of functional test board is also highlighted in this
chapter