Effectiveness of Nitrate Policy in Flanders (1990-2003): Modular Modelling and Response Analysis

The impact of current nitrate policy measures in Flanders is estimated. A modular modelling system has been developed for comparing response and pressure indicators and for decomposing the response impact of policy measures. Compared to 1990, the internalised manure surplus is reduced to zero, whereas the distance to target of the soil surface balance to the water quality standard dropped only with 58%. Source-linked and sink-related measures each account for about the half of the manure surplus reduction. The impact of abatement technologies is minor. The modular approach helps to unravel the discrepancy between pressure and response and to propose policy alternatives.abatement technology, DPSIR scheme, nitrogen pollution reduction, Agricultural and Food Policy, B41, C51, H21, K32,

Human-in-the-Loop Model Predictive Control of an Irrigation Canal

Until now, advanced model-based control techniques have been predominantly employed to control problems that are relatively straightforward to model. Many systems with complex dynamics or containing sophisticated sensing and actuation elements can be controlled if the corresponding mathematical models are available, even if there is uncertainty in this information. Consequently, the application of model-based control strategies has flourished in numerous areas, including industrial applications [1]-[3].Junta de Andalucía P11-TEP-812

Optimal Operation of the Multireservoir System in the Seine River Basin Using Deterministic and Ensemble Forecasts

International audienceThis article investigates the improvement of the operation of a four-reservoir system in the Seine River basin, France, by use of deterministic and ensemble weather forecasts and real-time control. In the current management, each reservoir is operated independently from the others and following prescribed rule-curves, designed to reduce floods and sustain low flows under the historical hydrological conditions. However, this management system is inefficient when inflows are significantly different from their seasonal average and may become even more inadequate to cope with the predicted increase in extreme events induced by climate change. In this work, a centralized real-time control system is developed to improve reservoirs operation by exploiting numerical weather forecasts that are becoming increasingly available. The proposed management system implements a well-established optimization technique, model predictive control (MPC), and its recently modified version that can incorporate uncertainties, tree-based model predictive control (TB-MPC), to account for deterministic and ensemble forecasts respectively. The management system is assessed by simulation over historical events and compared to the no-forecasts strategy based on rule-curves. Simulation results show that the proposed real-time control system largely outperforms the no-forecasts management strategy, and that explicitly considering forecast uncertainty through ensembles can compensate for the loss in performance due to forecast inaccuracy

Wetenschappelijk rapport MIRA 2009 & NARA 2009 Overschrijding kritische lasten

In deze studie werd de overschrijding van kritische lasten voor verzuring en vermesting bepaald voor natuur in Vlaanderen, en dit voor diverse toekomstscenario’s. Deze scenario’s omvatten enerzijds twee MIRA-scenario’s voor de emissie en depositie van potentieel verzurende stoffen (NHx, NOy en SOx), anderzijds drie NARA-scenario’s voor landgebruik, beide gecombineerd tot zes scenario’s en overspannen een periode van 2010 t.e.m. 2030

A new measurement of the structure functions PLL−PTT/epsilonP_{LL}-P_{TT}/epsilon and PLTP_{LT} in virtual Compton scattering at Q2=Q^2= 0.33 (GeV/c)2^2

The cross section of the $ep \to e' p' \gamma$ reaction has been measured at $Q^2 = 0.33$ (GeV/c)$^2$. The experiment was performed using the electron beam of the MAMI accelerator and the standard detector setup of the A1 Collaboration. The cross section is analyzed using the low-energy theorem for virtual Compton scattering, yielding a new determination of the two structure functions P_LL}-P_{TT}/epsilon and $P_{LT}$ which are linear combinations of the generalized polarizabilities of the proton. We find somewhat larger values than in the previous investigation at the same $Q^2$. This difference, however, is purely due to our more refined analysis of the data. The results tend to confirm the non-trivial $Q^2$-evolution of the generalized polarizabilities and call for more measurements in the low-$Q^2$ region ($\le$ 1 (GeV/c)$^2$).Comment: 9 pages, 10 figures. EPJA version. slight revisions in the text and figure