5,431 research outputs found
Tiny Codes for Guaranteeable Delay
Future 5G systems will need to support ultra-reliable low-latency
communications scenarios. From a latency-reliability viewpoint, it is
inefficient to rely on average utility-based system design. Therefore, we
introduce the notion of guaranteeable delay which is the average delay plus
three standard deviations of the mean. We investigate the trade-off between
guaranteeable delay and throughput for point-to-point wireless erasure links
with unreliable and delayed feedback, by bringing together signal flow
techniques to the area of coding. We use tiny codes, i.e. sliding window by
coding with just 2 packets, and design three variations of selective-repeat ARQ
protocols, by building on the baseline scheme, i.e. uncoded ARQ, developed by
Ausavapattanakun and Nosratinia: (i) Hybrid ARQ with soft combining at the
receiver; (ii) cumulative feedback-based ARQ without rate adaptation; and (iii)
Coded ARQ with rate adaptation based on the cumulative feedback. Contrasting
the performance of these protocols with uncoded ARQ, we demonstrate that HARQ
performs only slightly better, cumulative feedback-based ARQ does not provide
significant throughput while it has better average delay, and Coded ARQ can
provide gains up to about 40% in terms of throughput. Coded ARQ also provides
delay guarantees, and is robust to various challenges such as imperfect and
delayed feedback, burst erasures, and round-trip time fluctuations. This
feature may be preferable for meeting the strict end-to-end latency and
reliability requirements of future use cases of ultra-reliable low-latency
communications in 5G, such as mission-critical communications and industrial
control for critical control messaging.Comment: to appear in IEEE JSAC Special Issue on URLLC in Wireless Network
Poverty and Inequality in the UK: 2008
In this Commentary, we assess the changes to average incomes, inequality and poverty that have occurred under the first 10 years of the Labour government, with a particular focus on the changes that have occurred in the latest year of data. This analysis is based upon the latest figures from the DWP's Households Below Average Income (HBAI) series, published on 10 June 2008 (Department for Work and Pensions, 2008c). The HBAI series takes household income as its measure of living standards and is derived from the Family Resources Survey, a survey of around 28,000 households in the United Kingdom that asks detailed questions about income from a range of sources
Poverty and inequality in the UK: 2007
This Briefing Note provides an update on trends in living standards, income inequality and poverty. It uses the same approach to measuring income and poverty as the government employs in its Households Below Average Income (HBAI) publication. The analysis is based on the latest HBAI figures (published on 27 March 2007), providing information about incomes up to the year 2005-06. The measure of income used is net household weekly income, which has been adjusted to take account of family size ('equivalised'). The income amounts provided below are expressed as the equivalent for a couple with no children, and all changes given are in real terms (i.e. after adjusting for inflation). For the first time in recent years, data are available for the whole of the United Kingdom, not just Great Britain, but data for Northern Ireland are only available from 2002-03. Some comparisons over time are provided for Great Britain only, but others will compare statistics for GB before 2002-03 with those for the UK afterwards.
PLEASE NOTE: On 23 April 2007, the Department for Work and Pensions announced that an error had occurred when producing the latest Households Below Average Income publication. This Briefing Note was based on the same dataset and therefore suffers from similar errors. In response to revisions announced by the DWP in May 2007, we have now updated our findings in a revised press release and have produced a revised summary
Poverty and inequality in the UK: 2009
In this Commentary, we assess the changes to average incomes, inequality and poverty that have occurred since Labour came to power in 1997, with a particular focus on the changes that have occurred in the latest year of data. This analysis is based upon the latest figures from the DWP's Households Below Average Income (HBAI) series, published on 7 May 2009 (Department for Work and Pensions, 2009). The HBAI series takes household income as its measure of living standards, and is derived from the Family Resources Survey, a survey of around 25,000 households in the United Kingdom that asks detailed questions about income from a range of sources
Velocity dispersion estimates of APM galaxy clusters
We present 83 new galaxy radial velocities in the field of 18 APM clusters
with redshifts between 0.06 and 0.13. The clusters have Abell identifications
and the galaxies were selected within 0.75 hMpc in projection from their
centers. We derive new cluster velocity dispersions for 13 clusters using our
data and published radial velocities.
We analyze correlations between cluster velocity dispersions and cluster
richness counts as defined in Abell and APM catalogs. The correlations show a
statistically significant trend although with a large scatter suggesting that
richness is a poor estimator of cluster mass irrespectively of cluster
selection criteria and richness definition. We find systematically lower
velocity dispersions in the sample of Abell clusters that do not fulfill APM
cluster selection criteria suggesting artificially higher Abell richness counts
due to contamination by projection effects in this subsample.Comment: Accepted for publication in MNRA
Pensioner poverty over the next decade: what role for tax and benefit reform?
Recent falls in poverty amongst those aged 65 and over are unlikely to continue after 2007-08, even after the implementation of the proposals outlined in the Government's Pensions White Paper.
This report looks at the prospects for pensioner poverty in England over the next decade. The authors find that that the proportion of those aged 65 and over living in poverty is set to remain at its current level - around one-in-five - between 2007-08 and 2017-18. This is despite the overall increase in the generosity of state pensions arising from the Pensions White Paper, and the fact that younger cohorts are expected to have more private pension income and higher employment rates at older ages than those preceding them
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