Search results for "OPTIMA"
showing 10 items of 735 documents
Motor decision and modular control of an hyper-redundant system
2015
This thesis is aimed at better understanding how the Central Nervous System (CNS) plans and controls voluntary movements. When moving, humans must overcome intrinsic (e.g. choosing which muscles to activate) and extrinsic (e.g. choosing where to reach an object) redundancy, requiring selecting one motor solution among several potential ones. To better understand this process, we studied in parallel two important motor control theories: muscular synergies and motor decision. In a first part, we focused on intrinsic redundancy by testing the muscular synergies hypothesis. According to it, the CNS simplifies the control of muscles, in using a limited set of building blocks whose linear combina…
A Survey of Active Learning for Quantifying Vegetation Traits from Terrestrial Earth Observation Data
2021
The current exponential increase of spatiotemporally explicit data streams from satellite-based Earth observation missions offers promising opportunities for global vegetation monitoring. Intelligent sampling through active learning (AL) heuristics provides a pathway for fast inference of essential vegetation variables by means of hybrid retrieval approaches, i.e., machine learning regression algorithms trained by radiative transfer model (RTM) simulations. In this study we summarize AL theory and perform a brief systematic literature survey about AL heuristics used in the context of Earth observation regression problems over terrestrial targets. Across all relevant studies it appeared that…
Vegetation Types Mapping Using Multi-Temporal Landsat Images in the Google Earth Engine Platform
2021
Vegetation Types (VTs) are important managerial units, and their identification serves as essential tools for the conservation of land covers. Despite a long history of Earth observation applications to assess and monitor land covers, the quantitative detection of sparse VTs remains problematic, especially in arid and semiarid areas. This research aimed to identify appropriate multi-temporal datasets to improve the accuracy of VTs classification in a heterogeneous landscape in Central Zagros, Iran. To do so, first the Normalized Difference Vegetation Index (NDVI) temporal profile of each VT was identified in the study area for the period of 2018, 2019, and 2020. This data revealed strong se…
Composition des dépenses publiques et impacts sur la croissance économique : analyses théoriques et empiriques sur des panels de pays développés, éme…
2016
The economic role of the State has been the subject of much debate both from theoretical and the practical perspectives. The actors of these controversies include the objectors of the efficiency of the public intervention since Smith to the present days, Keynesians and economists of the synthesis. Topics ranging from principle of the invisible hand, tax, expectations, burden of the debt, crowding out effect, public sector production are treated through of such debates. The work explains the breakdown of public spending components and implications for countries at levels development (OECD, BRICS, and WAEMU). The study also indicated that the effects of the public spending and its components …
Optimal Sustainable Policies Under Pollution Ceiling: the Demographic Side
2014
AD; International audience; We study optimal sustainable policies in a benchmark logistic world (where both population and technological progress follow logistic laws of motion) subject to a pollution ceiling. The main policy in the hands of the benevolent planner is pollution abatement, ultimately leading to the control of a dirtiness index as in the early literature of the limits to growth literature. Besides inclusion of demographic dynamics, we also hypothesize that population size affects negatively the natural regeneration or assimilation rate, as a side product of human activities (like increasing pollution, deforestation, ...). We first characterize optimal sustainable policies. Und…
A multiple criteria decision model for analyzing and choosing among different development patterns for the Helsinki cargo harbor
1999
Abstract This paper describes a real application of a multicriteria approach to choosing among different options for developing the Helsinki harbor. In addition to the environmental impact assessment procedure, an analysis of the alternatives using the SMAA-method (Stochastic Multiobjective Acceptability Analysis) is carried out. The method applied here has been developed for situations in which the use of decision-makers’ preference information is not possible. Instead, the problem is described by typical weight vectors leading to each solution, taking into account the evident uncertainty embedded in the criteria values.
Bryophytes collected during the 12th “Iter Mediterraneum” (Tunisia, 24 March – 4 April, 2014). First contribution
2015
Part of the bryophytes collected during Iter Mediterraneum XII is listed. Some noteworthy species were found: Dicranella howei, had so far been recorded only doubtfully from Tunisia; Funaria hygrometrica, Grimmia laevigata, Grimmia trichophylla, Imbribryum alpinum, Pogonatum nanum, Rhynchostegium riparioides, Scleropodium touretii, Scorpiurium circinatum, Thamnobryum alopecurum, Timmiella barbuloides, Tortella squarrosa, Tortula muralis and Tortula vahliana, had not been reported from that country for more than half a century.
Second-best taxation for a polluting monopoly with abatement investment
2018
This paper characterizes the optimal tax rule to regulate a polluting monopoly when the firm has the possibility of investing in an abatement technology and the environmental damages are caused by a stock pollutant. The optimal policy is given by the stagewise feedback Stackelberg equilibrium of a dynamic policy game between a regulator and a monopolist. The regulator playing as the leader chooses an emission tax to maximize net social welfare, and the monopolist acting as the follower selects the output and the investment in abatement technology to maximize profits. We find that the optimal tax has two components. The first component is negative and equal to the gap between the marginal re…
Special functions for the study of economic dynamics: The case of the Lucas-Uzawa model
2008
The special functions are intensively used in mathematical physics to solve differential systems. We argue that they should be most useful in economic dynamics, notably in the assessment of the transition dynamics of endogenous economic growth models. We illustrate our argument on the famous Lucas-Uzawa model, which we solve by the means of Gaussian hypergeometric functions. We show how the use of Gaussian hypergeometric functions allows for an explicit representation of the equilibrium dynamics of all variables in level. The parameters of the involved hypergeometric functions are identified using the Pontryagin conditions arising from the underlying optimization problems. In contrast to th…
The path of R&D efficiency over time
2015
Abstract In this paper we investigate the pattern of R&D efficiency in terms of the number of product innovations achieved by firms over time. Using a panel dataset of Spanish manufacturing firms for the period 1990–2006, we follow the innovative performance of R&D active firms and observe that innovation rates change over firms' R&D histories. To explain these facts we propose a model that explicitly acknowledges the twofold composition of firms' R&D expenditures, comprising spending on both physical capital for R&D projects and payments to researchers. We regard this latter component of R&D as a source for dynamic returns to firms' R&D investments. Consequently firms' innovation outcomes …