8,163 research outputs found

    Technical Foundations to Cut Down Administrative Red Tape: The Case of the Canton of Vaud

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    In this paper, we describe an analysis framework we developed in order to analyze the implementation of a simplification strategy in a Swiss Canton. This strategy is based on a participatory analysis of services and on the development of eGovernment foundations through the use of open standards and open source software. This framework takes into account both the supply side of administrative services and the user uptake. We will furthermore present preliminary results of our survey.eGovernment; foundations; e-Services; users; standardization; case study

    Wavelet analysis of the multivariate fractional Brownian motion

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    The work developed in the paper concerns the multivariate fractional Brownian motion (mfBm) viewed through the lens of the wavelet transform. After recalling some basic properties on the mfBm, we calculate the correlation structure of its wavelet transform. We particularly study the asymptotic behavior of the correlation, showing that if the analyzing wavelet has a sufficient number of null first order moments, the decomposition eliminates any possible long-range (inter)dependence. The cross-spectral density is also considered in a second part. Its existence is proved and its evaluation is performed using a von Bahr-Essen like representation of the function \sign(t) |t|^\alpha. The behavior of the cross-spectral density of the wavelet field at the zero frequency is also developed and confirms the results provided by the asymptotic analysis of the correlation

    Unemployment Dynamics and the Cost of Business Cycles

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    In this paper, we investigate whether business cycles can imply sizable effects on average unemployment. First, using a reduced-form model of the labor market, we show that job finding rate fluctuations generate intrinsically a non-linear effect on unemployment: positive shocks reduce unemployment less than negative shocks increase it. For the observed process of the job finding rate in the US economy, this intrinsic asymmetry is enough to generate substantial welfare implications. This result also holds when we allow the job finding rate to be endogenous, provided the structural model is able to reproduce the volatility of the job finding rate. Moreover, the matching model embeds other non-linearities which alter the average job finding rate and so the business cycle cost.business cycle costs, unemployment dynamics

    Matching frictions, unemployment dynamics and the cost of business cycles

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    We investigate the welfare cost of business cycles implied by matching frictions. First, using the reduced-form of the matching model, we show that job finding rate fluctuations generate intrinsically a non-linear effect on unemployment: positive shocks reduce unemployment less than negative shocks increase it. For the observed process of the job finding rate in the US economy, this intrinsic asymmetry increases average unemployment, which leads to substantial business cycles costs. Moreover, the structural matching model embeds other non-linearities, which alter the average job finding rate and consequently the welfare cost of business cycles. Our theory suggests to subsidizing employment in order to dampen the impact of the job finding rate fluctuations on welfare.Business cycle costs; Unemployment dynamics; Matching

    Citizens and Noncitizens in Europe: European Union Measures Against Terrorism After September 11th

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    In the European Union, new anti-terror measures have had an impact on the lives of noncitizens, immigrants, and asylum-seekers. This Essay outlines the rights guaranteed to both citizens and noncitizens under the European Convention on Human Rights and the EU treaties and evaluates how these rights have limited harsh treatment of noncitizens in the fight against terrorism. Although suspicion and rejection of noncitizens are widespread, there remains hope for broadening the principles of equality and fundamental rights to third country nationals through an open conception of the notion of European citizenship

    Launcher attitude control: discrete-time robust design and gain-scheduling

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    In this paper, a robust multi-objective design for the control of a launcher during atmospheric flight is investigated. This approach is based on the Cross Standard Form formulation which allows to incorporate the various specifications of the launcher problem in a streamlined manner. An important feature of this approach is that a non-conventional LQG/LTR approach, required to satisfy time-domain specifications, can be embedded into a more general standard problem in order to account for frequency-domain robustness constraints. The specific form of this standard problem is also very interesting for gain scheduling

    Correction of upstream flow and hydraulic state with data assimilation in the context of flood forecasting

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    The present study describes the assimilation of river water level observations and the resulting improvement in flood forecasting. The Kalman Filter algorithm was built on top of a one-dimensional hydraulic model which describes the Saint-Venant equations. The assimilation algorithm folds in two steps: the first one was based on the assumption that the upstream flow can be adjusted using a three-parameter correction; the second one consisted of directly correcting the hydraulic state. This procedure was applied using a four- day sliding window over the flood event. The background error covariances for water level and discharge were repre- sented with anisotropic correlation functions where the cor- relation length upstream of the observation points is larger than the correlation length downstream of the observation points. This approach was motivated by the implementation of a Kalman Filter algorithm on top of a diffusive flood wave propagation model. The study was carried out on the Adour and the Marne Vallage (France) catchments. The correction of the upstream flow as well as the control of the hydraulic state during the flood event leads to a significant improve- ment in the water level and discharge in both analysis and forecast modes

    Emptiness Of Alternating Tree Automata Using Games With Imperfect Information

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    We consider the emptiness problem for alternating tree automata, with two acceptance semantics: classical (all branches are accepted) and qualitative (almost all branches are accepted). For the classical semantics, the usual technique to tackle this problem relies on a Simulation Theorem which constructs an equivalent non-deterministic automaton from the original alternating one, and then checks emptiness by a reduction to a two-player perfect information game. However, for the qualitative semantics, no simulation of alternation by means of non-determinism is known. We give an alternative technique to decide the emptiness problem of alternating tree automata, that does not rely on a Simulation Theorem. Indeed, we directly reduce the emptiness problem to solving an imperfect information two-player parity game. Our new approach can successfully be applied to both semantics, and yields decidability results with optimal complexity; for the qualitative semantics, the key ingredient in the proof is a positionality result for stochastic games played over infinite graphs

    Benefits and limitations of data assimilation for discharge forecasting using an event-based rainfall–runoff model

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    Mediterranean catchments in southern France are threatened by potentially devastating fast floods which are difficult to anticipate. In order to improve the skill of rainfall-runoff models in predicting such flash floods, hydrologists use data assimilation techniques to provide real-time updates of the model using observational data. This approach seeks to reduce the uncertainties present in different components of the hydrological model (forcing, parameters or state variables) in order to minimize the error in simulated discharges. This article presents a data assimilation procedure, the best linear unbiased estimator (BLUE), used with the goal of improving the peak discharge predictions generated by an event-based hydrological model Soil Conservation Service lag and route (SCS-LR). For a given prediction date, selected model inputs are corrected by assimilating discharge data observed at the basin outlet. This study is conducted on the Lez Mediterranean basin in southern France. The key objectives of this article are (i) to select the parameter(s) which allow for the most efficient and reliable correction of the simulated discharges, (ii) to demonstrate the impact of the correction of the initial condition upon simulated discharges, and (iii) to identify and understand conditions in which this technique fails to improve the forecast skill. The correction of the initial moisture deficit of the soil reservoir proves to be the most efficient control parameter for adjusting the peak discharge. Using data assimilation, this correction leads to an average of 12% improvement in the flood peak magnitude forecast in 75% of cases. The investigation of the other 25% of cases points out a number of precautions for the appropriate use of this data assimilation procedure
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