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Distribution by Scientific Domains

Humanities and Social Sciences	50%

Selected Abstracts

A novel fault management approach for DWDM optical networks

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 5 2006
W. Fawaz
Connection availability is considered as a critical metric when providing differentiated services in Wavelength-Division Multiplexing mesh networks. Indeed, one of the major concerns of optical network operators is related to improving the availability of services provided to their highest-class clients. Achieving this objective is possible through managing faults using the different classical protection schemes, namely the so-called dedicated and shared protection schemes. However, the majority of the work concerning protection schemes has considered the primary connections as equally important when contending for the use of the backup resources. As a main contribution in this paper, we therefore propose an improvement of the existing protection schemes through the introduction of relative priorities among the different primary connections contending for the access to the protection path. To evaluate numerically the benefits of the service differentiation feature introduced in our proposal, we first develop a mathematical model, based on which we derive explicit expressions for the average connection availabilities that result from both the classical protection schemes and the proposed priority-aware one. Through this model, we show how the availability of the highest-class clients is improved when deploying the proposed priority-aware protection scheme. Finally, with the same objective in mind, we develop a simulation study, where a given set of connection demands with predefined availability requirements is provisioned using different protection strategies. Through this study, we show that the priority-aware protection strategy satisfies service-availability requirements in a cost-effective manner compared with the classical protection schemes.Copyright © 2006 John Wiley & Sons, Ltd. [source]

When consensus choice dominates individualism: Jensen's inequality and collective decisions under uncertainty

QUANTITATIVE ECONOMICS, Issue 1 2010
Charles F. Manski
D7; D81; H42 Research on collective provision of private goods has focused on distributional considerations. This paper studies a class of problems of decision under uncertainty in which an efficiency argument for collective choice emerges from the mathematics of aggregating individual payoffs. Consider decision making when each member of a population has the same objective function, which depends on an unknown state of nature. If agents knew the state of nature, they would make the same decision. However, they may have different beliefs or may use different decision criteria to cope with their incomplete knowledge. Hence, they may choose different actions even though they share the same objective. Let the set of feasible actions be convex and the objective function be concave in actions, for all states of nature. Then Jensen's inequality implies that consensus choice of the mean privately chosen action yields a larger mean payoff than does individualistic decision making, in all states of nature. If payoffs are transferable, the mean payoff from consensus choice may be allocated to Pareto dominate individualistic decision making. I develop these ideas. I also use Jensen's inequality to show that a planner with the power to assign actions to the members of the population should not diversify. Finally, I give a version of the collective-choice result that holds with consensus choice of the median rather than mean action. [source]

Institutional competitiveness, social investment, and welfare regimes

REGULATION & GOVERNANCE, Issue 3 2007
Paul Bernard
Abstract Are the rather generous welfare regimes found in most European countries sustainable; that is, are they competitive in a globalizing economy? Or will they, on the contrary, be crowded out by the more austere and less expensive regimes generally found in liberal Anglo-Saxon countries? We first discuss this issue conceptually, focusing on the notions of institutional competitiveness, social investment, and short-term and long-term productivity. We then briefly present the results of an empirical study of 50 social indicators of policies and outcomes in 20 Organization for Economic Co-operation and Development (OECD) countries during the early 2000s. We conclude that welfare regimes have not been forced to converge through a "race to the bottom." There remain three distinct ways to face the "trilemma" of job growth, income inequality, and fiscal restraint: Nordic countries achieve high labor market participation through high social investment; Anglo-Saxon countries attain the same objective through minimal public intervention; while Continental European countries experience fiscal pressures because their social protection schemes are not promoting participation to the same extent. [source]

A critique of the World Health Organisation's evaluation of health system performance

HEALTH ECONOMICS, Issue 5 2003
Jeff Richardson
Abstract The World Health Organisation's (WHO) approach to the measurement of health system efficiency is briefly described. Four arguments are then presented. First, equity of finance should not be a criterion for the evaluation of a health system and, more generally, the same objectives and importance weights should not be imposed upon all countries. Secondly, the numerical value of the importance weights do not reflect their true importance in the country rankings. Thirdly, the model for combining the different objectives into a single index of system performance is problematical and alternative models are shown to alter system rankings. The WHO statistical analysis is replicated and used to support the fourth argument which is that, contrary to the author's assertion, their methods cannot separate true inefficiency from random error. The procedure is also subject to omitted variable bias. The econometric model for all countries has very poor predictive power for the subset of OECD countries and it is outperformed by two simpler algorithms. Country rankings based upon the model are correspondingly unreliable. It is concluded that, despite these problems, the study is a landmark in the evolution of system evaluation, but one which requires significant revision. Copyright © 2002 John Wiley & Sons, Ltd. [source]