48 research outputs found
A proof-of-proximity framework for device pairing in ubiquitous computing environments
Ad hoc interactions between devices over wireless networks in ubiquitous
computing environments present a security problem: the generation of shared secrets
to initialize secure communication over a medium that is inherently vulnerable to
various attacks. However, these ad hoc scenarios also offer the potential for physical
security of spaces and the use of protocols in which users must visibly demonstrate
their presence and/or involvement to generate an association. As a consequence,
recently secure device pairing has had significant attention from a wide community of
academic as well as industrial researchers and a plethora of schemes and protocols
have been proposed, which use various forms of out-of-band exchange to form an
association between two unassociated devices. These protocols and schemes have
different strengths and weaknesses – often in hardware requirements, strength against
various attacks or usability in particular scenarios. From ordinary user‟s point of
view, the problem then becomes which to choose or which is the best possible scheme
in a particular scenario.
We advocate that in a world of modern heterogeneous devices and
requirements, there is a need for mechanisms that allow automated selection of the
best protocols without requiring the user to have an in-depth knowledge of the
minutiae of the underlying technologies. Towards this, the main argument forming the
basis of this dissertation is that the integration of a discovery mechanism and several
pairing schemes into a single system is more efficient from a usability point of view
as well as security point of view in terms of dynamic choice of pairing schemes. In
pursuit of this, we have proposed a generic system for secure device pairing by
demonstration of physical proximity. Our main contribution is the design and
prototype implementation of Proof-of-Proximity framework along with a novel Co-
Location protocol. Other contributions include a detailed analysis of existing device
pairing schemes, a simple device discovery mechanism, a protocol selection
mechanism that is used to find out the best possible scheme to demonstrate the
physical proximity of the devices according to the scenario, and a usability study of
eight pairing schemes and the proposed system
System Support for Managing Invalid Bindings
Context-aware adaptation is a central aspect of pervasive computing
applications, enabling them to adapt and perform tasks based on contextual
information. One of the aspects of context-aware adaptation is reconfiguration
in which bindings are created between application component and remote services
in order to realize new behaviour in response to contextual information.
Various research efforts provide reconfiguration support and allow the
development of adaptive context-aware applications from high-level
specifications, but don't consider failure conditions that might arise during
execution of such applications, making bindings between application and remote
services invalid. To this end, we propose and implement our design approach to
reconfiguration to manage invalid bindings. The development and modification of
adaptive context-aware applications is a complex task, and an issue of an
invalidity of bindings further complicates development efforts. To reduce the
development efforts, our approach provides an application-transparent solution
where the issue of the invalidity of bindings is handled by our system,
Policy-Based Contextual Reconfiguration and Adaptation (PCRA), not by an
application developer. In this paper, we present and describe our approach to
managing invalid bindings and compare it with other approaches to this problem.
We also provide performance evaluation of our approach
Some variant of Tseng splitting method with accelerated Visco-Cesaro means for monotone inclusion problems
In this paper, we examine the convergence analysis of a variant of Tseng's splitting method for monotone inclusion problem and fixed point problem associated with an infinite family of -demimetric mappings in Hilbert spaces. The qualitative results of the proposed variant shows strong convergence characteristics under a suitable set of control conditions. We also provide a numerical example to demonstrate the applicability of the variant with some applications
Network Analysis of co-authorship system of University of Sindh authors on Science Direct
Many complex systems have been modelled and analyzed as complex networks. These systems are huge and complex in terms of number of interconnecting components. In this research, we have analyzed the co-authorship network of Sindh university authors on science direct to understand the connectivity pattern of authors who published their articles over time. This research has found that the connectivity pattern of the authors is highly heterogonous due to the emergence of hubs in this system. Further, this network has shown highly clustered behavior with small world effect. These findings based on network analysis suggests that the co-authorship system is depending on few authors frequently publishing multiple papers in this network
Enzymatically assisted extraction of antioxidant and anti-mutagenic compounds from radish (Raphanus sativus)
In addition to being sources of carbohydrates, protein, and fiber, vegetables, and fruits also represent important sources of micro-nutrients, including antioxidants, and anti-mutagens in the form of carotenoids, and polyphenols, such as flavonoids. We describe the enhanced extraction of these bioactive compounds from radish (Raphanus sativus L.) by use of an enzymic pre-treatment to break up starch, and the complex mix of polysaccharides, cellulose, hemicellulose, and pectin, which constitute the plant cell wall. The enzymic cocktail included cellulases, pectinases, amylases, glucanases, and hemicellulases. Response surface methodology (RSM) was utilized to maximally explore the yield by estimating extraction conditions, enzyme concentration, incubation time, temperature, pH, and extraction solvents. Extracted antioxidant activity was assayed in terms of total phenolics content (TPC), free radical scavenging (DPPH and ABTS tests), inhibition of linolic peroxidation assay, Reducing potential, and Trolox equivalent antioxidant capacity (TEAC). Two different bacterial mutant strains (TA-98, TA-100, S. typhimurium) were used by applying Ames bacterial test. It was concluded that highest desirability was achieved at 3.53% (w/w) of enzyme formulation, at pH of 6.1, incubation time 66.08 min and 46.08 °C temperature produced 19.2 g/100 g FW of crude extract which contains 45.9 mg GAE/g FW total phenolics contents, 0.480 mg/mL Reducing Power, 85.9% LA inhibition and 271.7 mmole/g FW of TEAC in fresh radish root. We found that radish extract was an excellent source of antioxidants that might be further investigated for commercial exploitation
TEXTAROSSA: Towards EXtreme scale Technologies and Accelerators for euROhpc hw/Sw Supercomputing Applications for exascale
International audienceTo achieve high performance and high energy efficiency on near-future exascale computing systems, three key technology gaps needs to be bridged. These gaps include: energy efficiency and thermal control; extreme computation efficiency via HW acceleration and new arithmetics; methods andtools for seamless integration of reconfigurable accelerators in heterogeneous HPC multi-node platforms. TEXTAROSSA aims at tackling this gap through a co-design approach to heterogeneous HPC solutions, supported by the integration and extension of HW and SW IPs, programming models and tools derived from European research
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