6,013 research outputs found
New Developments in Agricultural Policy Modelling and Consequences for Managing the Policy Analysis Systems
Last decade, the importance of multifunctionality and environmental issues in agricultural policies has been growing. This shift in scope of agricultural policy instruments implies an adjustment of the conventional ex-ante policy analysis systems. New requirements on input and output parameters will be needed. The objective of this paper is to show how the input/output management can be improved. Focus is on how the information management by the system can enhance the policy analysis and decision making and facilitate information flow and social support from the stakeholder debate.policy impact analysis, joint production, farmers' behaviour, knowledge flow Organisation, Agricultural and Food Policy, C8, Q18,
On the thermal and thermodynamic (In)stability of methylammonium lead halide perovskites
The interest of the scientific community on methylammonium lead halide perovskites (MAPbX3, X = Cl,
Br, I) for hybrid organic-inorganic solar cells has grown exponentially since the first report in 2009. This
fact is clearly justified by the very high efficiencies attainable (reaching 20% in lab scale devices) at a
fraction of the cost of conventional photovoltaics. However, many problems must be solved before a
market introduction of these devices can be envisaged. Perhaps the most important to be addressed
is the lack of information regarding the thermal and thermodynamic stability of the materials towards
decomposition, which are intrinsic properties of them and which can seriously limit or even exclude
their use in real devices. In this work we present and discuss the results we obtained using non-ambient
X-ray diffraction, Knudsen effusion-mass spectrometry (KEMS) and Knudsen effusion mass loss (KEML)
techniques on MAPbCl3, MAPbBr3 and MAPbI3. The measurements demonstrate that all the materials
decompose to the corresponding solid lead (II) halide and gaseous methylamine and hydrogen halide,
and the decomposition is well detectable even at moderate temperatures (~60 °C). Our results suggest
that these materials may be problematic for long term operation of solar devices
Hydrographs' attenuation in sewers. Effects on stormwater source control regulation
International audienceIn this paper we propose an empirical approach to quantify the hydrographs' attenuation in sewers. The purpose is to evaluate attenuation's consequences for the scale-transfer between the parcel and the catchment in urban settings, and in particular for stormwater source control (SC) regulation. In fact, SC regulation practices often consider this scale-transfer by a linear approach. We draw a formulation for the attenuation of peaks in partially full pipes, and we assess, by a sensitivity analysis, the respective weights of the different pipes' and hydrographs' characteristics on attenuation. We found that the driving factors of the peak attenuation vary according to the distance from the outlet, and we draw possible guidelines for SC regulation
Conversion of Artificial Recurrent Neural Networks to Spiking Neural Networks for Low-power Neuromorphic Hardware
In recent years the field of neuromorphic low-power systems that consume
orders of magnitude less power gained significant momentum. However, their
wider use is still hindered by the lack of algorithms that can harness the
strengths of such architectures. While neuromorphic adaptations of
representation learning algorithms are now emerging, efficient processing of
temporal sequences or variable length-inputs remain difficult. Recurrent neural
networks (RNN) are widely used in machine learning to solve a variety of
sequence learning tasks. In this work we present a train-and-constrain
methodology that enables the mapping of machine learned (Elman) RNNs on a
substrate of spiking neurons, while being compatible with the capabilities of
current and near-future neuromorphic systems. This "train-and-constrain" method
consists of first training RNNs using backpropagation through time, then
discretizing the weights and finally converting them to spiking RNNs by
matching the responses of artificial neurons with those of the spiking neurons.
We demonstrate our approach by mapping a natural language processing task
(question classification), where we demonstrate the entire mapping process of
the recurrent layer of the network on IBM's Neurosynaptic System "TrueNorth", a
spike-based digital neuromorphic hardware architecture. TrueNorth imposes
specific constraints on connectivity, neural and synaptic parameters. To
satisfy these constraints, it was necessary to discretize the synaptic weights
and neural activities to 16 levels, and to limit fan-in to 64 inputs. We find
that short synaptic delays are sufficient to implement the dynamical (temporal)
aspect of the RNN in the question classification task. The hardware-constrained
model achieved 74% accuracy in question classification while using less than
0.025% of the cores on one TrueNorth chip, resulting in an estimated power
consumption of ~17 uW
Factors and mechanisms affecting University-Industry interactions: evidence from Southern Italy
This paper aims to identify and analyze factors, motivations and mechanisms affecting collaborative forms of university-industry interactions in the context of the metropolitan area of Naples (Southern Italy). This work presents the results of a study designed and implemented through a partnership between University of Naples Federico II (UNF) and the Industrial Association of Naples (UIN). We used data retrieved from 88 firms that had interacted at least once with at least one Department of the University of Naples Federico II in the last 3 years. Firms belonged to different sectors and to different size categories, thus results will cover interactions activities based on those two elements. Results obtained during the field research were used to understand mechanisms and motives adopted by firms to collaborate with universities
Urban stormwater source control policies: why and how?
International audienceStormwater source control is becoming a common strategy for urban stormwater management in many countries. It relies on regulations or other policy instruments compelling or inciting to implement, for each new urban development, small-scale facilities to locally store and manage stormwater. Local authorities that pioneered source control since the 1980s have already observed that small-scale facilities systematically implemented over a catchment are able to influence its hydrological behaviour. This capability is the main strength of source control, as it allows compensation for the negative effects of urbanization. Yet, it also represents its main risk: if initial decision-making is not sufficiently accurate, source control can produce long term negative effects. Because of its current spreading, source control will acquire an increasing role as a driver of hydrological changes in urban catchments, and the directions of these changes depend on current policy-making practices. This paper presents an analysis and a critical discussion of the main objectives that policy-makers attribute to stormwater source control. The investigation is based on a sample of French case studies, completed by a literature review for international comparison. It identifies four main objectives, some typical of urban stormwater management and some more innovative: flood reduction, receiving waters protection, sustainable development, costs reduction. The discussion focuses on how current policy-making practices are able to translate these objectives in concrete policy instruments, and on which knowledge and tools could improve this process. It is shown that for some objectives, basic knowledge is available, but the creation of policy instruments effective at the catchment scale and adapted to local conditions is still problematic. For others, substantial lacks of knowledge exist, casting doubts on long term effectiveness of current policy instruments. Research directions are identified to improve source control policies and thus the future hydrologic behaviour of many urban catchments
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