Deterministic Annealing and Nonlinear Assignment

For combinatorial optimization problems that can be formulated as Ising or Potts spin systems, the Mean Field (MF) approximation yields a versatile and simple ANN heuristic, Deterministic Annealing. For assignment problems the situation is more complex -- the natural analog of the MF approximation lacks the simplicity present in the Potts and Ising cases. In this article the difficulties associated with this issue are investigated, and the options for solving them discussed. Improvements to existing Potts-based MF-inspired heuristics are suggested, and the possibilities for defining a proper variational approach are scrutinized.Comment: 15 pages, 3 figure

On the Accuracy of Equivalent Antenna Representations

The accuracy of two equivalent antenna representations, near-field sources and far-field sources, are evaluated for an antenna installed on a simplified platform in a series of case studies using different configurations of equivalent antenna representations. The accuracy is evaluated in terms of installed far-fields and surface currents on the platform. The results show large variations between configurations. The root-mean-square installed far-field error is 4.4% for the most accurate equivalent representation. When using far-field sources, the design parameters have a large influence of the achieved accuracy. There is also a varying accuracy depending on the type of numerical method used. Based on the results, some recommendations on the choice of sub-domain for the equivalent antenna representation are given. In industrial antenna applications, the accuracy in determining e.g. installed far-fields and antenna isolation on large platforms are critical. Equivalent representations can reduce the fine-detail complexity of antennas and thus give an efficient numerical descriptions to be used in large-scale simulations. The results in this paper can be used as a guideline by antenna designers or system engineers when using equivalent sources

Sustainability Aspects of In-Situ Bioremediation of Polluted Soil in Developing Countries and Remote Regions

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Potential output in DSGE models

In view of the increasing use of Dynamic Stochastic General Equilibrium (DSGE) models in the macroeconomic projections and the policy process, this paper examines, both conceptually and empirically, alternative notions of potential output within DSGE models. Furthermore, it provides historical estimates of potential output/output gaps on the basis of selected DSGE models developed by the European System of Central Banks’ staff. These estimates are compared to the corresponding estimates obtained applying more traditional methods. Finally, the paper assesses the usefulness of the DSGE model-based output gaps for gauging inflationary pressures. JEL Classification: E32, E37, E52monetary policy, potential output, simulation and forecasting models

Potential Output in DSGE Models

In view of the increasing use of Dynamic Stochastic General Equilibrium (DSGE) models in the macroeconomic projections and the policy process, this paper examines, both conceptually and empirically, alternative notions of potential output within DSGE models. Furthermore, it provides historical estimates of potential output/output gaps on the basis of selected DSGE models developed by the European System of Central Banks’ staff. These estimates are compared to the corresponding estimates obtained applying more traditional methods. Finally, the paper assesses the usefulness of the DSGE model-based output gaps for gauging inflationary pressures.potential output, simulation and forecasting models, monetary policy

The opinions of some stakeholders on the European Union Timber Regulation (EUTR): an analysis of secondary sources

The EU Timber Regulation (EUTR) is the most recent effort by the European Union (EU) to curb imports of illegally sourced timber. The regulation raises important questions concerning the international timber trade. In order to successfully implement this regulation it is of paramount importance to classify the actors concerned, and examine how they regard it. The current study records and summarizes opinion statements of stakeholders as found in different online publications. Though the problem of illegal logging and its associated trade is acknowledged by all parties, there are concerns as to whether the EUTR is the proper instrument to address this issue. Whilst some stakeholders see the EUTR as advantageous for their businesses, others see it as an impediment. Law enforcement, lack of guidance, and bureaucracy were other issues raised. The trade-off between effective legislation and ease of trade was also highlighted. Transparent and consistent application of the EUTR, with clear guidelines for exerting due diligence, should diminish the degree of possible unwanted side-effects such as trade diversion and substitution of temperate timber for tropical timber.JRC.H.3-Forest Resources and Climat

Information, Multifaceted Forest Ownership and Timber Supply

Existing decision support systems (DSS) do not account for forest owner heterogeneity, nor do they explicitly model the reaction of forest owners to policy. Hence, current DSS are suitable for response analysis, but much less useful for policy impact assessment or forecasting. The current study presents a theoretical model of harvesting behavior which provides the basis for a simulation model, Expected Value Asymmetries (EVA), useful for analyzing how timber supply and forest characteristics are affected when forest owners differ as to responsiveness to information, risk aversion, and patience as regards postponement of harvesting revenues. The simulation results clearly indicate that the model is well adapted for considering forest owner heterogeneity when assessing the impact of policy on the inter-temporal development of forest resources and timber market conditions. Finally, it is outlined how EVA could integrate forest owner specific harvesting behavior in an augmented Decision Support System (DSS), thus addressing the inability of DSS operational at pan-European level to model the interaction between policy and forest management decisions.JRC.H.3-Forest Resources and Climat