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See detailMeasuring Quantity-Quality Trade-Offs in Regulation: the Brazilian Freight Railways Case
Estache, Antonio; Perelman, Sergio ULg; Trujillo, Lourdes

in Annals of Public and Cooperative Economics = Annales de l'Economie Publique, Sociale et Coopérative (2007), 78(1), 1-20

The quantity vs. quality trade-offs in network industries are well known from the theoretical literature and have been the subject of many empirical assessments, although mostly for the telecoms and ... [more ▼]

The quantity vs. quality trade-offs in network industries are well known from the theoretical literature and have been the subject of many empirical assessments, although mostly for the telecoms and energy sectors. The purpose of this paper is to expand the evidence for the railway sector by documenting the importance of this trade-off in the context of the Brazilian freight railway industry reform, the first example of a railway sector in which tariff revisions are subject to joint output and quality performance indicators. The analysis is based on the calculation of the Malmquist productivity index proposed by Fare et al. (1995). The decomposable nature of this total factor productivity (TFP) index reveals the prevalence of quantity-quality trade-offs up to the end of the reform period, but a positive correlation between them during the period just afterwards. This type of information would certainly be useful for regulation purposes, particularly as an alternative way of taking into account quality without introducing complex, and very often ineffective, penalty schemes. [less ▲]

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See detailMeasuring Social Economy in the Framework of the National Accounts
Mertens de Wilmars, Sybille ULg

in Defourny, Jacques; Develtere, Patrick; Fonteneau, Bénédicte (Eds.) et al The Worldwide making of the social economy Innovations and changes (2009)

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See detailMEASURING SOIL ORGANIC CARBON IN CROPLANDS AT REGIONAL SCALE USING AIRBORNE IMAGING SPECTROSCOPY
Stevens, Antoine; Udelhoven, Thomas; Denis, Antoine ULg et al

in Geoderma (2010), 158

Conventional sampling techniques are often too expensive and time consuming to meet the amount of data required in soil monitoring or modelling studies. The emergence of portable and flexible ... [more ▼]

Conventional sampling techniques are often too expensive and time consuming to meet the amount of data required in soil monitoring or modelling studies. The emergence of portable and flexible spectrometers could provide the large amount of spatial data needed. In particular, the ability of airborne imaging spectroscopy to cover large surfaces in a single campaign and to study the spatial distribution of soil properties with a high spatial resolution represents an opportunity for improving the monitoring of soil characteristics and soil threats such as the decline of soil organic matter in the topsoil. However, airborne imaging spectroscopy has been generally applied over small areas with homogeneous soil types and surface conditions. Here, five hyperspectral images acquired with the AHS-160 sensor (430 nm–2540 nm) were analysed with the objective to map soil organic carbon (SOC) at a regional scale. The study area, covering a surface of ∼420 km2 and located in Luxembourg, is characterized by different soil types and a high variation in SOC contents. Reflectance data were related to surface SOC contents of bare croplands by means of 3 different multivariate calibration techniques: partial least square regression (PLSR), penalized-spline signal regression (PSR) and support vector machine regression (SVMR). The performance of these statistical tools was tested under different combinations of calibration/validation sets (global and local calibrations stratified according to agro-geological zones, soil type and image number). Under global calibration, the Root Mean Square Error in the Predictions reached 5.3–6.2 g C kg−1. Under local calibrations, this error was reduced by a factor up to 1.9. SOC maps of bare agricultural fields were produced using the best calibration model. Two map excerpts were shown, which display intra- and inter-field variability of SOC contents possibly related to topography and land management. [less ▲]

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See detailMeasuring some cognitive effects of using control technology, 'NATO Advanced Research Workshop', Liège, novembre 1992
Denis, Brigitte ULg

in Denis, Brigitte (Ed.) Control technology in elementary education (1992)

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See detailMeasuring Technical Efficiency in European Railways: A Panel Data Approach
Gathon, Henry-Jean ULg; Perelman, Sergio ULg

in Journal of Productivity Analysis (1992), 3

We estimate a factor requirement frontier for European railways using a panel data approach in which technical efficiency is assumed to be endogencously determined. This approach has two main outcomes. On ... [more ▼]

We estimate a factor requirement frontier for European railways using a panel data approach in which technical efficiency is assumed to be endogencously determined. This approach has two main outcomes. On one hand, it allows the identification of factors influencing technical efficiency, and on the other hand, it allows the estimation of alternative efficiency indicators free of these influences. In the case under study, a particular attention is devoted to an autonomy indicator representing the managerial freedom, with respect to public authorities, experienced by firms, that appears to be positively correlated with technical efficiency. [less ▲]

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See detailMeasuring the body, measuring through the body
Vangeebergen, Thomas ULg

Conference (2014, June 13)

Body is a particular relevant way to tackle design processes, because of the multiplicity of status it can acquire during these processes: a source of information, a target to fit, a device to perform, a ... [more ▼]

Body is a particular relevant way to tackle design processes, because of the multiplicity of status it can acquire during these processes: a source of information, a target to fit, a device to perform, a complex technology, an apparatus for the users. A specific body is presented in this paper: the measured body. Trough racial anthropology, sport performances, demographic statistics, medical treatments, psycho-cognitive surveys, quantified self, or in many other contexts, human body is subject to a wide range of various measures. I would on my own propose some thoughts grounded on field exploration, concerning sensory analysis practices, in various laboratories. According to the symmetrical glaze STS have gave from the beginning to both human and non-humans, objects and subjects, the body is for a start itself one of the “stuffs” overlapping categories, blurring distinctions between things and persons, at the same a time a given and an object to perform. The measures of the body, and made with/through the body, highlight how it could be enacted, revealed, understood, improved by technology, especially when it requires some quantitative data. But it allows us also to grasp how the body is viewed simultaneously as a technological device and as the data origin, to intervene during complex practices (e.g. standardization, lab experiments, and marketing surveys). One of the numerous outcomes of such research could be the role of these bodily measurements in the definition of the actors, as well individuals than collectives. By the way it takes on a share on the network tying body to numerical data and to materiality-other-than-human, to measure the body/ through the body seems to afford socio-materiality in a particularly productive manner. Many scholars have inquired about numbers, how they could bring objectivity, how they produce confidence and security, and how finally they participate to black-box the measures themselves. Here, the aim is to understand the specificity of the body as measurement issue, being the interface of the-objects-to-be-measured and the instrument-of-measure. [less ▲]

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See detailMeasuring the Degree of Market Power in the Export Demand for Nigerian Cocoa: An Analysis of Dutch Market
Nwachukwu, I.N.; Onyenweaku, C. E.; Nwaru, J. C. et al

in Journal of Social and Development Sciences (2011), 2(3), 94-103

The study examined the degree of market power in the export demand for Nigerian Cocoa with focus on the Dutch Market. The study covered the periods of 1961–2007 and data comprised published national ... [more ▼]

The study examined the degree of market power in the export demand for Nigerian Cocoa with focus on the Dutch Market. The study covered the periods of 1961–2007 and data comprised published national aggregates on specific trade and macroeconomic variables from reputable sources. Two Stage Least Squares (2 SLS) approach was used in the estimation after instrumenting for simultaneity and establishing stationarity alongside cointegration relationship. Findings, on the demand side, showed that the demand for cocoa increases as income of Netherlands (importing country) increases. Total production of the non–participating countries traced out a positive relationship with demand for cocoa by the importing country while the coefficient of price of Coffee (substitute crop) possessed a negative sign. On the supply relation side, the demand for the export crop has a negative sign, indicating decreasing marginal output with respect to cost while the proxy for ocean freight rate with its negative sign, imply increasing export cost. The result further showed that there is relative competitiveness in the Dutch market on the strength of a market power coefficient -0.712 with a Lerner index of 0.122. Based on the findings, the study calls for government intervention in the agricultural export subsector with the aim to revitalize the country’s agricultural export capacity and enhance her market power via increased market shares. These interventions could be in the form of input/production subsidies, targeted export promotion programs, farm settlement, expanded export processing zones to mention but a few. [less ▲]

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See detailMeasuring the effect of amantadine in chronic anoxic minimally conscious state.
Schnakers, Caroline ULg; Hustinx, Roland ULg; Vandewalle, Gilles ULg et al

in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(2), 225-7

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See detailMeasuring the equivalence of item difficulty in the various versions of an international test
Grisay, Aletta; Monseur, Christian ULg

in Studies in Educational Evaluation (2007), 33(1), 69-86

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See detailMeasuring the extent of linkage disequilibrium in commercial pig populations
Harmegnies, N.; Farnir, Frédéric ULg; DAVIN, Fabienne ULg et al

in Animal Genetics (2006), 37(3), 225-231

To evaluate the extent of linkage disequilibrium in domestic pigs, we genotyped 33 and 44 unrelated individuals from two commercial populations for 29 and five microsatellite markers located on ... [more ▼]

To evaluate the extent of linkage disequilibrium in domestic pigs, we genotyped 33 and 44 unrelated individuals from two commercial populations for 29 and five microsatellite markers located on chromosomes 15 and 2 respectively. A high proportion of marker pairs up to 40 cM apart exhibited significant linkage disequilibrium in both populations. Pair-wise r(2) values averaged between 0.15 and 0.50 (depending on chromosome and population) for markers < 1 cM apart and declined to values of 0.05 for more distant syntenic markers. Our results suggest that both populations underwent a bottleneck approximately 20 generations ago, which reduced the effective population size from thousands to < 200 animals. [less ▲]

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See detailMeasuring the flowing properties of powders and grains
Lumay, Geoffroy ULg; Boschini, Frédéric ULg; traina, Karl et al

in Powder Technology (2012), 224

A granular material is a complex system which exhibits non-trivial transitions between the static, the quasi-static and the dynamical states. Indeed, an assembly of grains can behave like a solid or a ... [more ▼]

A granular material is a complex system which exhibits non-trivial transitions between the static, the quasi-static and the dynamical states. Indeed, an assembly of grains can behave like a solid or a fluid according to the applied stress. In between solid and fluid granular states, very slow dynamics are observed. When a complete macroscopic characterization of a powder is needed, all these granular states have to be precisely analyzed. In this paper, we show how three measurement techniques can be used to measure the physical properties of a powder. The measurements are based on classical tests modified to meet the recent fundamental researches on granular materials. The static properties of the powder are analyzed through the shape of a heap. The quasi-static behavior is studied with the analysis of the compaction dynamics. Finally, the dynamical regime is monitored through the flow in a rotating drum. In order to illustrate how these measurements can be used in practical cases, analyses are performed with three types of granular materials: silicon carbide abrasives, flours and rice. These selected materials allow to show the influence of the different parameters (grain size, grain size distribution, grain shape) on the macroscopic properties of the assembly. Moreover, these studies show the pertinence of the parameters obtained with the proposed techniques for the rheological characterization of powders and grains. [less ▲]

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See detailMeasuring the importance of competition: a new formulation of the problem
Damgaard, Christian; Fayolle, Adeline ULg

in Journal of Ecology (2010), (98), 1-6

1. Currently, there is a debate among plant ecologists on the concepts of the intensity of competition and the importance of competition, which is central to many issues of modern plant population ecology ... [more ▼]

1. Currently, there is a debate among plant ecologists on the concepts of the intensity of competition and the importance of competition, which is central to many issues of modern plant population ecology and plant community ecology. 2. It is problematic that the current measures of intensity and importance of competition, typically, are reported as dimensionless indices because they hide the fact that both indices are functions of plant density and the level of the environmental gradient. 3. Here, a new formulation of the concepts is suggested, which explicitly highlights the functional dependencies on plant density and the level of the environmental gradient. The new measures are a generalization of the previous indices and correspond to the previous indices in the case of a simple experimental design. 4. The suggested measures of the intensity and importance of competition are exemplified using data from a response surface competition experiment between Agrostis capillaris and Festuca ovina along a herbicide gradient, where the expected clear effect of plant density was demonstrated. 5. Synthesis. As the suggested measures of the intensity and importance of competition explicitly highlight the functional dependencies on plant density and the level of the environmental gradient, we think that they will help to ensure a closer connection between experimental plant ecology and the attempts to model plant populations and communities. [less ▲]

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See detailMeasuring the Influence of the kth Largest Variable on Functions over the Unit Hypercube
Marichal, Jean-Luc; Mathonet, Pierre ULg

in Modeling Decisions for Artificial Intelligence 7th International Conference, MDAI 2010 (2010)

By considering a least squares approximation of a given square integrable function f: [0,1]^n\to R by a shifted L-statistic function (a shifted linear combination of order statistics), we define an index ... [more ▼]

By considering a least squares approximation of a given square integrable function f: [0,1]^n\to R by a shifted L-statistic function (a shifted linear combination of order statistics), we define an index which measures the global influence of the k-th largest variable on f. We show that this influence index has appealing properties and we interpret it as an average value of the difference quotient of f in the direction of the k-th largest variable or, under certain natural conditions on f, as an average value of the derivative of f in the direction of the k-th largest variable. We also discuss a few applications of this index in statistics and aggregation theory. [less ▲]

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See detailMeasuring the interactions among variables of functions over the unit hypercube
Marichal, Jean-Luc; Mathonet, Pierre ULg

in Journal of Mathematical Analysis & Applications (2011), 380

By considering a least squares approximation of a given square integrable function f: [0,1]^n\to\R by a multilinear polynomial of a specified degree, we define an index which measures the overall ... [more ▼]

By considering a least squares approximation of a given square integrable function f: [0,1]^n\to\R by a multilinear polynomial of a specified degree, we define an index which measures the overall interaction among variables of f. This definition extends the concept of Banzhaf interaction index introduced in cooperative game theory. Our approach is partly inspired from multilinear regression analysis, where interactions among the independent variables are taken into consideration. We show that this interaction index has appealing properties which naturally generalize several properties of the Banzhaf interaction index. In particular, we interpret this index as an expected value of the difference quotients of f or, under certain natural conditions on f, as an expected value of the derivatives of f. Finally, we discuss a few applications of the interaction index in aggregation function theory. [less ▲]

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See detailMeasuring the Interactions among Variables of Functions over the Unit hypercube
Marichal, Jean-Luc; Mathonet, Pierre ULg

in Modeling Decisions for Artificial Intelligence 7th International Conference, MDAI 2010 (2010)

By considering a least squares approximation of a given square integrable function f:[0,1]^n to R by a multilinear polynomial of a specified degree, we define an index which measures the overall ... [more ▼]

By considering a least squares approximation of a given square integrable function f:[0,1]^n to R by a multilinear polynomial of a specified degree, we define an index which measures the overall interaction among variables of f. This definition extends the concept of Banzhaf interaction index introduced in cooperative game theory. Our approach is partly inspired from multilinear regression analysis, where interactions among the independent variables are taken into consideration. We show that this interaction index has appealing properties which naturally generalize the properties of the Banzhaf interaction index. In particular, we interpret this index as an expected value of the difference quotients of f or, under certain natural conditions on f, as an expected value of the derivatives of f. These interpretations show a strong analogy between the introduced interaction index and the overall importance index defined by Grabisch and Labreuche. Finally, we discuss a few applications of the interaction index. [less ▲]

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See detailMeasuring the phase of the scattering amplitude with vortex beams
Ivanov, Igor ULg

in Physical Review. D : Particles and Fields (2012), 85(7), 07600110

We show that colliding vortex beams instead of (approximate) plane waves can lead to a direct measurement of how the overall phase of the plane wave scattering amplitude changes with the scattering angle ... [more ▼]

We show that colliding vortex beams instead of (approximate) plane waves can lead to a direct measurement of how the overall phase of the plane wave scattering amplitude changes with the scattering angle. Since vortex beams are coherent superpositions of plane waves with different momenta, their scattering amplitude receives contributions from plane wave amplitudes with distinct kinematics. These contributions interfere, leading to the measurement of their phase difference. Although interference exists for any generic wave packet collision, we show that using vortex beams dramatically enhances sensitivity to the phase in comparison with nonvortex beams. Since the overall phase is inaccessible in a plane wave collision, this measurement would be of great importance for a number of topics in hadronic physics, for example, meson production in the resonance region, physics of nucleon resonances, and small angle elastic hadron scattering. [less ▲]

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See detailMeasuring the Social Economy in the Framework of the National Accounts
Mertens de Wilmars, Sybille ULg

in Defourny, Jacques; Nyssens, Marthe; Develtere, Patrick (Eds.) et al The worldwide making of the social economy. Innovations and changes (2009)

Sybille Mertens examines a new major development in the recognition of the social economy (nonprofit organisations, cooperatives, mutuals, social enterprises. She describes the efforts of numerous ... [more ▼]

Sybille Mertens examines a new major development in the recognition of the social economy (nonprofit organisations, cooperatives, mutuals, social enterprises. She describes the efforts of numerous research teams around the world to improve the statistical knowledge and economic measurement of this sector, with aspecific focus on the development of satellite accounts. [less ▲]

Detailed reference viewed: 125 (8 ULg)