94 research outputs found
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Mobile Audiovisual Terminal: System Design and Subjective Testing in DECT and UMTS networks
It is anticipated that there will shortly be a requirement
for multimedia terminals that operate via mobile
communications systems. This paper presents a functional specification
for such a terminal operating at 32 kb/s in a digital
European cordless telecommunications (DECT) and universal
mobile telecommunications system (UMTS) radio network. A terminal
has been built, based on a PC with digital signal processor
(DSP) boards for audio and video coding and decoding. Speech
coding is by a phonetically driven code-excited linear prediction
(CELP) speech coder and video coding by a block-oriented hybrid
discrete cosine transform (DCT) coder. Separate channel coding
is provided for the audio and video data. The paper describes the
techniques used for audio and video coding, channel coding, and
synchronization. Methods of subjective testing in a DECT network
and in a UMTS network are also described. These consisted of
subjective tests of first impressions of the mobile audioâvisual
terminal (MAVT) quality, interactive tests, and the completion
of an exit questionnaire. The test results showed that the quality
of the audio was sufficiently good for comprehension and the
video was sufficiently good for following and repeating simple
mechanical tasks. However, the quality of the MAVT was not
good enough for general use where high-quality audio and video
was needed, especially when transmission was in a noisy radio
environment
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Parallel H.263 Encoder in Normal Coding Mode
A parallel H.263 video encoder, which utilises spatial para1 elism,
has been modelled using a multi-threaded program. Spatial
parallelism is a technique where an image is subdivided into equal
parts (as far as physically possible) and each part is proces!;ed by
a separate processor by computing motion and texture mding
with all processors cach acting on a different part of thc ]mag.
This method leads to a performance increase, which is roughly in
proportion to the number of parallel processors used
Perfect design or practical study? A workshop on navigating the challenges of community based prevention research
Subject: There is a shared interest among public health researchers in tackling methodological issues surrounding community based research, and on moving beyond a focus on individual level change. As part of a project on community empowerment funded by the Peopleâs Health Trust, we have conducted a feasibility study on quantitative and economic evaluation of complex community-based interventions. To understand different quantitative methods that can be used to evaluate community empowerment interventions, we have undertaken a methodological literature review that identified the following sets of challenges: Defining population of interest â interventions taking place at a community level are not specifically targeted at a well-defined group of individuals. Therefore it is challenging to even find those who are affected by an intervention. Diverse and un-prescribed effects â the effect of community empowerment interventions are likely broad, suggesting we need to measure multiple outcomes in order to detect change. This increases the likelihood of detecting spurious change and can require a lot of resource. Furthermore, in many cases these outcomes are not pre-defined by a programme (i.e. communities choose their own foci)
COVID-19 disruption to cervical cancer screening in England
INTRODUCTION: In England, routine invitations for cervical screening were reduced between April 2020 and June 2020 due to the COVID-19 pandemic. We quantify the impact of COVID-19 disruptions on attendance and excess diagnoses of cervical cancer (CC). METHODS: Using Public Health England CC screening data on laboratory samples received in 2018 as a baseline we quantify the reduction in screening attendances due to the COVID-19 pandemic between April 2020 and March 2021 for women aged 25â64. We model the impact on excess CC diagnoses assuming once invitations resume 87.5% of women attend within 12 months and 12.5% delay screening for 3 or 5 years (depending on age). RESULTS: The number of samples received at laboratories was 91% lower than expected during April, 85% during May and 43% during June 2020 compared to the same period in 2018. Although on average laboratories received 12.6% more samples between August 2020 and April 2021 than over the same months in 2018, by April 2021 there was a short fall of 200,949 samples (6.4% fewer than in 2018). An excess of 41 CC (4.0 per 100,000 women with a maximum screening delay of 12 months) are predicted to occur among the estimated 1,024,794 women attending this screening round with a delay. An excess of 60 CC (41.0 per 100,000 women) are predicted to occur among the estimated 146,391 women who do not attend this screening round. CONCLUSION: Prompt restoration of cervical screening services limited the impact on excess CC diagnoses. However, in 2020 a 6.4% shortfall of screening samples was observed. Every effort should be made to reassure these women that services are open and safe to attend
Customized television: Standards compliant advanced digital television
This correspondence describes a European Union supported collaborative project called CustomTV based on the premise that future TV sets will provide all sorts of multimedia information and interactivity, as well as manage all such services according to each userâs or group of userâs preferences/profiles. We have demonstrated the potential of recent standards (MPEG-4 and MPEG-7) to implement such a scenario by building
the following services: an advanced EPG, Weather Forecasting, and Stock Exchange/Flight Information
Age-related variation in non-breeding foraging behaviour and carry-over effects on fitness in an extremely long-lived bird
Senescence has been widely documented in wild vertebrate populations, yet the proximate drivers of ageârelated declines in breeding success, including allocation tradeâoffs and links with foraging performance, are poorly understood. For longâlived, migratory species, the nonâbreeding period represents a critical time for investment in selfâmaintenance and restoration of body condition, which in many species is linked to fitness. However, the relationships between age, nonâbreeding foraging behaviour and fitness remain largely unexplored. We performed a crossâsectional study, investigating ageârelated variation in the foraging activity, distribution and diet of an extremely longâlived seabird, the wandering albatross Diomedea exulans, during the nonâbreeding period. Eightyâtwo adults aged 8â33 years were tracked with geolocatorâimmersion loggers, and body feathers were sampled for stable isotope analysis. We tested for variation in metrics of foraging behaviour and linked ageârelated trends to subsequent reproductive performance. There was an ageârelated decline in the number of landings (a proxy of foraging effort) during daylight hours, and a decrease in body feather ÎŽÂčÂłC values in older males but not females, yet this did not accompany an ageârelated shift in distributions. Males conducted fewer landings than females, and the sexes showed some spatial segregation, with males foraging further south, likely due to their differential utilization of winds. Although younger (<20 years) birds had higher foraging effort, they all went on to breed successfully the following season. In contrast, among older (20+ years) birds, individuals that landed more often were more likely to defer breeding or fail during incubation, suggesting they have lower foraging success. As far as we are aware, this is the first demonstration of an ageâspecific carryâover effect of foraging behaviour in the nonâbreeding period on subsequent reproductive performance. This link between foraging behaviour and fitness in late but not early adulthood indicates that the ability of individuals to forage efficiently outside the breeding period may be an important driver of fitness differences in old age. A plain language summary is available for this article
The size-dependent morphology of Pd nanoclusters formed by gas condensation
Size-selected Pd nanoclusters in the size range from 887 to 10â000 atoms were synthesized in a magnetron sputtering, inert gas condensation cluster beam source equipped with a time of flight mass filter. Their morphologies were investigated using scanning transmission electron microscopy (STEM) and shown to be strongly size-dependent. The larger clusters exhibited elongated structures, which we attribute to the aggregation, through multiple collisions, of smaller clusters during the gas phase condensation process. This was confirmed from the atomically resolved STEM images of the Pd nanoclusters, which showed smaller primary clusters with their own crystalline structures
Threats to seabirds: A global assessment
We present the first objective quantitative assessment of the threats to all 359 species of seabirds, identify the main challenges facing them, and outline priority actions for their conservation. We applied the standardised Threats Classification Scheme developed for the IUCN Red List to objectively assess threats to each species and analysed the data according to global IUCN threat status, taxonomic group, and primary foraging habitat (coastal or pelagic). The top three threats to seabirds in terms of number of species affected and average impact are: invasive alien species, affecting 165 species across all the most threatened groups; bycatch in fisheries, affecting fewer species (100) but with the greatest average impact; and climate change/severe weather, affecting 96 species. Overfishing, hunting/trapping and disturbance were also identified as major threats to seabirds. Reversing the top three threats alone would benefit two-thirds of all species and c. 380 million individual seabirds (c. 45% of the total global seabird population). Most seabirds (c. 70%), especially globally threatened species, face multiple threats. For albatrosses, petrels and penguins in particular (the three most threatened groups of seabirds), it is essential to tackle both terrestrial and marine threats to reverse declines. As the negative effects of climate change are harder to mitigate, it is vital to compensate by addressing other major threats that often affect the same species, such as invasive alien species, bycatch and overfishing, for which proven solutions exist
Investment Evaluation of a Suburban Coastal Transport System
This paper aims at determining the optimum viable solution of an investment on a suburban coastal shipping system in the area of Athens. More specifically the development of a sea transport system, alternative to the existing road one, that connects Piraeus with the southern suburban coastal area of Athens is examined. The best viable solution of such an undertaking is considered to be the one, which under the existing constraints maximises the total profit that derives from this investment. The variables used for the formation of the constraints are the number of vessels used, the routing and the price of the services. The article focuses on the financing alternatives of the project and their impact on its economic efficiency and concludes with the best viable scenarios and optimum solution
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