63 research outputs found
Are EU spatial ex ante coexistence regulations proportional?
Get PDFThe EU is currently struggling to implement coherent coexistence regulations on genetically modified (GM) and non-GM crops in all member states. While it stresses that any approach needs to be “proportionate to the aim of achieving coexistence”, very few studies have actually attempted to assess whether the proposed spatial ex ante coexistence regulations (SEACERs) satisfy this proportionality condition. In this article, we define proportionality as a functional relationship which is weakly increasing in the incentives for coexistence. We propose a spatial framework based on an existing landscape and introduce the new concept of shadow factor as a measure for the opportunity costs induced by SEACERs. This enables comparing the proportionality of (i) rigid SEACERs which are based on large isolation distances imposed on GM farmers versus (ii) flexible SEACERs based on pollen barrier agreements between neighboring farmers. Our theoretical and empirical findings argue for flexibility as rigid SEACERs violate the proportionality condition and, hence, are not consistent with the objectives of the EU.policy analysis, GIS, shadow factor, Agricultural and Food Policy, Crop Production/Industries,
Risk and De-Collectivisation: Evidence from the Czech Republic
Get PDFThe replacement of wage-labour farms by family farms in Central and Eastern Europe during the transformation has been more limited than was initially expected. In this paper a formal framework is developed in order to analyse the behaviour of family farms and socialist-style farms in the presence of risk, given the typical post-socialist environment. Management incentives, ownership structure, lump-sum transfers and consumption choices are shown to have the potential to limit the size of family farms relative to socialist-style farms. The hypotheses are tested with survey data collected by the author in the Czech Republic.transition, agriculture, structural change, risk, survey data, Risk and Uncertainty, D21, D81, O18, Q12,
Economics of spatial coexistence of genetically modified and conventional crops: Oilseed rape in Central France
Get PDFEurope is currently struggling to implement coherent coexistence regulations on genetically modified (GM) and non-GM crops in all EU Member States. We conduct simulations with the software ArcView® on a GIS dataset of a hypothetical case of GM herbicide tolerant oilseed rape cultivation in Central France. Our findings show that rigid coexistence rules, such as large distance requirements, may impose a severe burden on GM crop production in Europe. These rules are not proportional to the farmers’ basic incentives for coexistence and hence not consistent with the objectives of the European Commission. More alarming, we show that in densely planted areas a domino-effect may occur. This effect raises coexistence costs and even adds to the non-proportionality of rigid coexistence regulations. Instead, we show that flexible measures would be preferable since they are proportional to the incentives for coexistence and, hence, less counterproductive for European agriculture.regulation, GIS modelling, domino-effect, Crop Production/Industries,
Effect of mechanical properties of paint on the craquelure propagation within historical paintings modelled as multilayered structure
No full textIntention-Aware Routing to Minimise Delays at Electric Vehicle Charging Stations
No full textEn-route charging stations allow electric vehicles to greatly extend their range. However, as a full charge takes a considerable amount of time, there may be significant waiting times at peak hours. To address this problem, we propose a novel navigation system, which communicates its intentions (i.e., routing policies) to other drivers. Using these intentions, our system accurately predicts congestion at charging stations and suggests the most efficient route to its user. We achieve this by extending existing time-dependent stochastic routing algorithms to include the battery's state of charge and charging stations. Furthermore, we describe a novel technique for combining historical information with agent intentions to predict the queues at charging stations. Through simulations we show that our system leads to a significant increase in utility compared to existing approaches that do not explicitly model waiting times or use intentions, in some cases reducing waiting times by over 80% and achieving near-optimal overall journey times.Software and Computer TechnologyElectrical Engineering, Mathematics and Computer Scienc
A possible examination method for observing agriculture
No full textOn the basis of our examinations we have come to the
conclusion that longitudinal examinations are the simplest and
most up-to-date methods as well as the most cost-efficient ones
to follow the decision-making, preparatory data collecting,
processing and analysing opportunities serving the
sustainability of agriculture better and better together with
tracing down the feedback about the decisions to see if the
given measure has really resulted in reaching the objectives.
The method was proved to be able to supply both micro-and
macro-level information in the desired breakdown, groupings
and systems of connections.
The development successive (panel) examination that we
applied can serve as the basis of making decisions affecting
huge areas by means of total listings and breakdowns.
Moreover, it can also control their effects and aftermaths.
We suggest the implementation of introducing this data
collecting and information supplying method declared to be
desirable also by the European Union. Implementation could
be eased to a great extent by the fact that it is available for the
organisations, as well
Designing for Post-Processing: A Case Study of a 3D Printed Surgical Instrument
No full textIn this report a design is proposed for a laparoscopic gripper that can be manufactured with metal 3D printing and polished with mass finishing. The design is a continuation of the development of a laparoscopic gripper that can be 3D printed in plastic. Laparoscopic grippers 3D printed solely out of metal have not yet been presented. Laparoscopic instruments are limited in width to 5 mm, which is bordering the manufacturing limits of selective laser melting 3D printing. The use of 3D printing for medical instruments has the potential to customise instruments specific to patient, procedure, and surgeon. Metal 3D printing can produce complex parts, albeit with a high surface roughness. Post-processing is required to reduce the surface roughness. Mass finishing techniques are a group of mechanical polishing techniques, of which centrifugal disc finishing was selected due to its capability to process parts in bulk without requiring workpiece fixation. To synthesise a suitable design, the processes of printing and polishing were analysed to formulate design guidelines. The analyses were part literature study, part experimental study. The experimental study had the aim to quantify and supplement the guidelines found in handbooks and articles. Using a novel visualisation technique, the polishing of different geometries could be distilled into quantitative design considerations. Here, a marking lacquer was applied to the surface of workpieces, which remained on unpolished surfaces. In this experiment a number of features were used, which corresponded to aspects that had potential to be used in the design. The use of channels was deemed unviable for polishing at the scale of laparoscopic instruments, which required the removal of these from the design. Mass finishing polishing removed the coarse surface structure present on metal produced with 3D printing, and brought surfaces of the test pieces to 0.05 mm below their desired width. Application of the design guidelines to the laparoscopic instrument was focused on making printing and polishing compatible joints. The laparoscopic gripper has two degrees of freedom for increased manoeuvrability. The features that comprise the joint are protrusions and cut-outs, sinusoidal gear arches, and actuation cable guides. Each of these features were dimensioned with values from the guidelines. The joint design required a number of components to be split so polishing access could be guaranteed, specifically for the cable guides. This had the added benefit of having each part be orientated during printing individually. The final design is based on application of the relevant design guidelines, and has been validated using scale models for mechanical stability
Fertilization: trade-offs between manure abatement and plant productivity
Get PDFIn 2005, 30% of the Flemish farms faced a manure excess, while at aggregated level still 9.7% of the emission rights were unused. This means that, despite the various possibilities, Flemish farmers do not succeed in an effective exchange of manure between farms. In current paper is shown how inorganic fertilizer use influences the use and exchange of organic nitrogen. Because of the mutual interdependency between organic and inorganic nitrogen emission rights (or quota), inorganic nitrogen use limits the emission rights for organic nitrogen. Utilisation of these emission rights are analysed as a trade-offs choice between plant productivity (use of inorganic nitrogen) and manure disposal, as the major abatement alternative of manure production. Farmers still prefer inorganic fertilizers because of their effect on plant productivity and income. However, by changing the quota rent of organic nitrogen, the fertilization behaviour can be influenced. A higher quota rent of organic nitrogen would increase the use of manure. This trade-off behaviour seriously influences effectiveness of policies. When the objective is to lower the total nitrogen use, a mere reduction of organic quota can partially be counteracted by a higher inorganic nitrogen use. When the objective is to better spread the manure, increasing the quota rent for deficit farms will increase their acceptance of manure.manure abatement, nutrient emission rights, Tobit model, Crop Production/Industries,
Tabu-Based Large Neighbourhood Search for Time/Sequence-Dependent Scheduling Problems with Time Windows
No full textAn important class of scheduling problems is characterised by time-dependency and/or sequence-dependency with time windows. We introduce and analyze four algorithmic ideas for this class: a novel hybridization of adaptive large neighbourhood search (ALNS) and tabu search (TS), randomized generic neighbourhood operators, a partial sequence dominance heuristic, and a fast insertion strategy. An evaluation of the resulting hybrid algorithm on two domains, a real-world multi-orbit agile Earth observation satellite scheduling problem, and an order acceptance and scheduling problem, shows that it robustly outperforms a mixed integer programming method, a two-stage hybridization of ALNS and TS, and recent state-of-the-art metaheuristic methods.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Algorithmic
Discovery of Optimal Solution Horizons in Non-Stationary Markov Decision Processes with Unbounded Rewards
No full textInfinite-horizon non-stationary Markov decision processes provide a general framework to model many real-life decision-making problems, e.g., planning equipment maintenance. Unfortunately, these problems are notoriously difficult to solve, due to their infinite dimensionality. Often, only the optimality of the initial action is of importance to the decision-maker: once it has been identified, the procedure can be repeated to generate a plan of arbitrary length. The optimal initial action can be identified by finding a time horizon so long that data beyond it has no effect on the initial decision. This horizon is known as a solution horizon and can be discovered by considering a series of truncations of the problem until a stopping rule guaranteeing initial decision optimality is satisfied. We present such a stopping rule for problems with unbounded rewards. Given a candidate policy, the rule uses a mathematical program that searches for other possibly optimal initial actions within the space of feasible truncations. If no better action can be found, the candidate action is deemed optimal. Our rule runs faster than comparable rules and discovers shorter, more efficient solution horizons.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.AlgorithmicsEnergie and Industri
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