Linköping University

About: Linköping University is a education organization based out in Linköping, Sweden. It is known for research contribution in the topics: Population & Health care. The organization has 15671 authors who have published 50013 publications receiving 1542189 citations.

A true single-phase-clock dynamic CMOS circuit technique

Abstract: The authors describe two dynamic circuit techniques, using only a single-phase clock which is never inverted. This class of circuits has the advantages of simple clock distribution, small area for clock lines reduced clock skew problems, and high speed. Several examples are demonstrated.

Visual screening of Swedish children: An ophthalmological evaluation

Abstract: The aim of this thesis was to assess the vision screening system and ocular status in Sweden of today, yesterday and tomorrow and to compare the prevalence of ocular disease before and after screening and treatment with special focus on amblyopiaScreening has been defmed by the United States Commission of Chronic Illness (1957) as "the presumptive identification of unrecognized disease or defect by the application oftests, examinations or other procedures, which can be rapidly applied Screening tests sort out apparently well persons who probably have a disease from those who probably do not" The screening system for eye disorders was introduced in the whole country in the beginning of 1970 and has not been evaluated in a greater area and for a longer period Neither has an evaluation been done according to WHO's instructions Amblyopia is the most common cause to visual impairment in one eye The visual system is developing mostly in the first years of life and it is important to treat amblyopia in early childhood The three first papers are retrospective studies and the fourth a prospective study The study group in the first and second paper consisted of all children born 1982 in three Swedish cities from newborn until the age of 10 years The children have been tested eight to nine times at the Child Health Care Centres and in school during this time The sensitivity and specificity of visual screening were 92% and 97% respectively The prevalence of ametropia was 77%, strabismus 31%, amblyopia ≤ 7 29% and organic lesions 02% We compared the prevalence of amblyopia today with the time before screening was introduced in Sweden This comparison shows that serious amblyopia has been reduced about 10 times with screening and treatmentLoss of vision in the non-amblyopic eye was investigated by studying patients with amblyopia at four visual rehabilitation centres Approximately 12% of the people with amblyopia ≤ 03 will eventually become visually handicapped due to lesions in the better eyeDespite visual screening and treatment there are some children left with residual amblyopia We investigated ways to improve the system by lowering the age for visual acuity examination from 4 to 3 years and at the same time two vision charts were compared We found that the testability rate for 3-year-olds was almost the same for the Lea Symbol chart and the HVOT chart (828% and 848% respectively) Testability was about 10% higher at 4 years The positive predictive value was lower at 3 years (58%) than has previously been found at 4 years (72%)Conclusion: In these studies we have found that screening is justified for the following reasons: visual screening is efficient in terms of sensitivity and specificity and many important ocular conditions are detected in this process; the prevalence of serious amblyopia is greatly reduced by screening and treatment; loss of vision in the non-amblyopic eye is a significant problem, which can be greatly reduced by screening and treatment, thereby saving expenses for the societyThe following has been found regarding the design of visual screening: visual acuity testing is efficient in detecting visual disorders from 4 years and up; visual acuity can be tested at 3 years, but with lower positive predictive value; the most widely used charts in Sweden and internationally, the HVOT chart and the Lea Symbols chart perform equally well in visual acuity testing of 3-year-old and 4-year-old children

SkePU: a multi-backend skeleton programming library for multi-GPU systems

Abstract: We present SkePU, a C++ template library which provides a simple and unified interface for specifying data-parallel computations with the help of skeletons on GPUs using CUDA and OpenCL. The interface is also general enough to support other architectures, and SkePU implements both a sequential CPU and a parallel OpenMP backend. It also supports multi-GPU systems.Copying data between the host and the GPU device memory can be a performance bottleneck. A key technique in SkePU is the implementation of lazy memory copying in the container type used to represent skeleton operands, which allows to avoid unnecessary memory transfers.We evaluate SkePU with small benchmarks and a larger application, a Runge-Kutta ODE solver. The results show that a skeleton approach to GPU programming is viable, especially when the computation burden is large compared to memory I/O (the lazy memory copying can help to achieve this). It also shows that utilizing several GPUs have a potential for performance gains. We see that SkePU offers good performance with a more complex and realistic task such as ODE solving, with up to 10 times faster run times when using SkePU with a GPU backend compared to a sequential solver running on a fast CPU.

A population-based cohort study of socio-demographic risk factors for COVID-19 deaths in Sweden

Abstract: As global deaths from COVID-19 continue to rise, the world's governments, institutions, and agencies are still working toward an understanding of who is most at risk of death. In this study, data on all recorded COVID-19 deaths in Sweden up to May 7, 2020 are linked to high-quality and accurate individual-level background data from administrative registers of the total population. By means of individual-level survival analysis we demonstrate that being male, having less individual income, lower education, not being married all independently predict a higher risk of death from COVID-19 and from all other causes of death. Being an immigrant from a low- or middle-income country predicts higher risk of death from COVID-19 but not for all other causes of death. The main message of this work is that the interaction of the virus causing COVID-19 and its social environment exerts an unequal burden on the most disadvantaged members of society.