8,896 research outputs found
No Benefit Tourists: A Single Market without Free Movement?
Among EU governments and political parties, there is a rising tendency to claim that intra-EU migration puts a serious strain on the sustainability of welfare provision. Several countries are enforcing measures aimed at limiting the access of other EU citizens to unemployment schemes, health care assistance, etc., and also calling on the EU to tighten rules to end "benefit tourism". However, Commission reports have shown how minimal the impact of "benefit tourism" is on welfare scheme budgets. Does this political attitude, which exposes the growing concerns of the traditional parties about the competition of right wing populism, risk adding further barriers to labour mobility and to the portability of rights, especially in a time of widening gaps in employment differentials? How much of the welfare financing difficulties do the intra-EU flows account for? Does this identitarian rhetoric add up to a race to the bottom in social provisions? Should a European response, in defence of the single market, aim to establish a level playing field rather than accommodating social competition
Boundary smoothness of analytic functions
We consider the behaviour of holomorphic functions on a bounded open subset
of the plane, satisfying a Lipschitz condition with exponent , with
, in the vicinity of an exceptional boundary point where all such
functions exhibit some kind of smoothness. Specifically, we consider the
relation between the abstract idea of a bounded point derivation on the algebra
of such functions and the classical complex derivative evaluated as a limit of
difference quotients. We obtain a result which applies, for example, when the
open set admits an interior cone at the special boundary point.Comment: 14 pages. This revision corrects a misprint on p.12: In equation (3),
should have been . Also a misprint on page 14 in the
formula for . The validity of the argument is not affected and the
result stand
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Large Families of Ternary Sequences with Aperiodic Zero Correlation Zone Sequences for a Multi-Carrier DS-CDMA System
A new method for generating families of ternary spreading sequences is presented. The sequences have aperiodic zero correlation zones and large families are created for a specific sequence length. The sequences are proposed as spreading sequences to provide high capacity and cancel multipath and multiple access interference (MAI) in a single carrier (SC) or multi-carrier (MC) direct-spread code division multiple access (DS-CDMA) system. A Multi-carrier DS-CDMA system is simulated that employs the new sequences as spreading sequences in a multipath channel. Bit error rates (BER) and frame error rates (FER) for a range of Eb/No values are presented and it is demonstrated that the proposed sequences improve the BER and FER performance when used in place of masked Walsh Codes for the frequency selective fading channel evaluated, when a single correlator receiver is used on each sub-carrier
Low-complexity medium access control protocols for QoS support in third-generation radio access networks
One approach to maximizing the efficiency of
medium access control (MAC) on the uplink in a future wideband
code-division multiple-access (WCDMA)-based third-generation
radio access network, and hence maximize spectral efficiency,
is to employ a low-complexity distributed scheduling control
approach. The maximization of spectral efficiency in third-generation
radio access networks is complicated by the need to
provide bandwidth-on-demand to diverse services characterized
by diverse quality of service (QoS) requirements in an interference
limited environment. However, the ability to exploit the full
potential of resource allocation algorithms in third-generation
radio access networks has been limited by the absence of a metric
that captures the two-dimensional radio resource requirement,
in terms of power and bandwidth, in the third-generation radio
access network environment, where different users may have
different signal-to-interference ratio requirements. This paper
presents a novel resource metric as a solution to this fundamental
problem. Also, a novel deadline-driven backoff procedure has
been presented as the backoff scheme of the proposed distributed
scheduling MAC protocols to enable the efficient support of
services with QoS imposed delay constraints without the need
for centralized scheduling. The main conclusion is that low-complexity
distributed scheduling control strategies using overload
avoidance/overload detection can be designed using the proposed
resource metric to give near optimal performance and thus maintain
a high spectral efficiency in third-generation radio access
networks and that importantly overload detection is superior to
overload avoidance
Spread spectrum techniques for indoor wireless IR communications
Multipath dispersion and fluorescent light
interference are two major problems in indoor
wireless infrared communications systems. Multipath
dispersion introduces intersymhol interference
at data rates above 10 Mb/s, while
fluorescent light induces severe narrowband
interference to baseband modulation schemes
commonly used such as OOK and PPM. This
article reviews the research into the application
of direct sequence spread spectrum techniques
to ameliorate these key channel impairments
without having to resort to complex signal processing
techniques. The inherent properties of a
spreading sequence are exploited in order to
combat the ISI and narrowband interference. In
addition, to reduce the impact of these impairments,
the DSSS modulation schemes have
strived to be bandwidth-efficient and simple to
implement. Three main DSSS waveform techniques
have been developed and investigated.
These are sequence inverse keying, complementary
sequence inverse keying, and M-ary biorthogonal
keying (MBOK). The operations of
the three systems are explained; their performances
were evaluated through simulations and
experiments for a number of system parameters,
including spreading sequence type and length.
By comparison with OOK, our results show that
SIK, CSIK, and MBOK are effective against
multipath dispersion and fluorescent light interference
becausc the penalties incurred on the
DSSS schemes are between 0-7 dB, while the
penalty on OOK in the same environment is
more than 17 dB. The DSSS solution for IR
wireless transmission demonstrates that a transmission
waveform can he designed to remove
the key channel impairments in a wireless IR
system
Pervasive Algebras and Maximal Subalgebras
A uniform algebra on its Shilov boundary is {\em maximal} if is
not and there is no uniform algebra properly contained between and
. It is {\em essentially pervasive} if is dense in whenever
is a proper closed subset of the essential set of . If is maximal,
then it is essentially pervasive and proper. We explore the gap between these
two concepts. We show the following: (1) If is pervasive and proper, and
has a nonconstant unimodular element, then contains an infinite descending
chain of pervasive subalgebras on . (2) It is possible to imbed a copy of
the lattice of all subsets of into the family of pervasive subalgebras of
some . (3) In the other direction, if is strongly logmodular, proper
and pervasive, then it is maximal. (4) This fails if the word \lq strongly' is
removed. We discuss further examples, involving Dirichlet algebras,
algebras, Douglas algebras, and subalgebras of . We
develop some new results that relate pervasiveness, maximality and relative
maximality to support sets of representing measures
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