8,820 research outputs found

    No Benefit Tourists: A Single Market without Free Movement?

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    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

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    We consider the behaviour of holomorphic functions on a bounded open subset of the plane, satisfying a Lipschitz condition with exponent α\alpha, with 0<α<10<\alpha<1, 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), α\alpha should have been 1−α1-\alpha. Also a misprint on page 14 in the formula for Ra−LaR_a-L_a. The validity of the argument is not affected and the result stand

    Low-complexity medium access control protocols for QoS support in third-generation radio access networks

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    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

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    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

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    A uniform algebra AA on its Shilov boundary XX is {\em maximal} if AA is not C(X)C(X) and there is no uniform algebra properly contained between AA and C(X)C(X). It is {\em essentially pervasive} if AA is dense in C(F)C(F) whenever FF is a proper closed subset of the essential set of AA. If AA is maximal, then it is essentially pervasive and proper. We explore the gap between these two concepts. We show the following: (1) If AA is pervasive and proper, and has a nonconstant unimodular element, then AA contains an infinite descending chain of pervasive subalgebras on XX. (2) It is possible to imbed a copy of the lattice of all subsets of N\N into the family of pervasive subalgebras of some C(X)C(X). (3) In the other direction, if AA 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, A(U)A(U) algebras, Douglas algebras, and subalgebras of H∞(D)H^\infty(\mathbb{D}). We develop some new results that relate pervasiveness, maximality and relative maximality to support sets of representing measures
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