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See detailOutils technologiques pour gérer la qualité microbiologique des aliments
Clinquart, Antoine ULg

in Belgian Association for Meat Science and Technology (Ed.) Journée d’étude MICROBIOLOGIE ET VIANDE : QUE FAIRE DEMAIN ? (2006)

Même si elles peuvent contribuer de manière très spectaculaire à la maîtrise de la qualité microbiologique des aliments, les techniques de conservation elles-mêmes ne sont pourtant qu’un moyen de maîtrise ... [more ▼]

Même si elles peuvent contribuer de manière très spectaculaire à la maîtrise de la qualité microbiologique des aliments, les techniques de conservation elles-mêmes ne sont pourtant qu’un moyen de maîtrise parmi d’autres… Deux facteurs principaux sont tout simplement la qualité initiale –en particulier la qualité microbiologique- des aliments ou des ingrédients qui les constituent et l’hygiène observée au cours de leur production, de leur transformation et de leur distribution. De plus, un effet « obstacle » n’est reproductible que dans des conditions précises, par exemple pour ce qui concerne le nombre de microorganismes, la composition de l’aliment, les conditions d’ambiance, etc… Une technique de conservation doit donc être validée dans des conditions données (p.ex. par validation de la durée de vie microbiologique permettant d’estimer la D.L.C. d’un produit). Toute modification de ces conditions ne permet plus de garantir la maîtrise de la qualité microbiologique. Il convient par ailleurs d’évaluer l’effet d’une contamination accidentelle de la denrée par un microorganisme pathogène, au cours de sa production, de sa transformation ou de sa distribution (test de croissance après inoculation artificielle de la denrée, encore appelé « challenge testing »). L’établissement et le respect de critères microbiologiques, de bonnes pratiques de fabrication et de procédures d’assurance qualité sont des points clés de la maîtrise de la qualité et de la sécurité sanitaire des aliments. Des progrès significatifs sont en cours et sont encore attendus dans les prochaines années. [less ▲]

Detailed reference viewed: 107 (10 ULg)
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See detailOutlier detection in satellite data using spatial coherence
Alvera Azcarate, Aïda ULg; Sirjacobs, Damien ULg; Barth, Alexander ULg et al

in Remote Sensing of Environment (2012), 119

Satellite data sets often contain outliers (i.e., anomalous values with respect to the surrounding pixels), mostly due to undetected clouds and rain or to atmospheric and land contamination. A methodology ... [more ▼]

Satellite data sets often contain outliers (i.e., anomalous values with respect to the surrounding pixels), mostly due to undetected clouds and rain or to atmospheric and land contamination. A methodology to detect outliers in satellite data sets is presented. The approach uses a truncated Empirical Orthogonal Function (EOF) basis. The information rejected by this EOF basis is used to identify suspect data. A proximity test and a local median test are also performed, and a weighted sum of these three tests is used to accurately detect outliers in a data set. Most satellite data undergo automated quality-check analyses. The approach presented exploits the spatial coherence of the geophysical fields, therefore detecting outliers that would otherwise pass such checks. The methodology is applied to infrared sea surface temperature (SST), microwave SST and chlorophyll-a concentration data over different domains, to show the applicability of the technique to a range of variables and temporal and spatial scales. A series of sensitivity tests and validation with independent data are also conducted. [less ▲]

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See detailOutlier detection with the minimum covariance determinant estimator in practice
Fauconnier, Cécile ULg; Haesbroeck, Gentiane ULg

in Statistical Methodology (2009), 6(4), 363-379

Robust statistics has slowly become familiar to all practitioners. Books entirely devoted to the subject are without any doubts responsible for the increased practice of robust statistics in all fields of ... [more ▼]

Robust statistics has slowly become familiar to all practitioners. Books entirely devoted to the subject are without any doubts responsible for the increased practice of robust statistics in all fields of applications. Even classical books often have at least one chapter (or parts of chapters) which develops robust methodology. The improvement of computing power has also contributed to the development of a wider and wider range of available robust procedures. However, this success story is now menacing to get backwards: non specialists interested in the application of robust methodology are faced with a large set of (assumed equivalent) methods and with over-sophistication of some of them. Which method should one use? How the (numerous) parameters should be optimaly tuned? These questions are not so easy to answer for non specialists! One could then argue that default procedures are available in most statistical softwares (Splus, R, SAS, Matlab,...). However, using as illustration the detection of outliers in multivariate data, it is shown that, on one hand, it is not obvious that one would feel confident with the output of default procedures, and that, on the other hand, trying to understand thoroughly the tuning parameters involved in the procedures might require some extensive research. This is not conceivable when trying to compete with the classical methodology which (while clearly unreliable) is so straightfoward. The aim of the paper is to help the practitioners willing to detect in a reliable way outliers in a multivariate data set. The chosen methodology is the Minimum Covariance Determinant estimator being widely available and intuitively appealing. [less ▲]

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See detailOutlier identification of differential item functioning in multiple groups
Magis, David ULg; De Boeck, Paul

Conference (2010, July)

Differential item functioning (DIF) has received increasing focus in the past decades. Recently, Magis and De Boeck (2009) proposed to identify differentially functioning items as outliers in a one ... [more ▼]

Differential item functioning (DIF) has received increasing focus in the past decades. Recently, Magis and De Boeck (2009) proposed to identify differentially functioning items as outliers in a one-dimensional space of DIF measures, using robust statistical tools for outlier identification. The purpose of this talk is to present an extension of this approach for the case of more than one focal group. In this multiple group framework, items can be characterized by multiple vectors of DIF measures, one for each focal group, so that a multivariate DIF space is obtained. DIF items can then be identified as outliers in this multivariate space, based on robust multivariate estimators of location and dispersion. The MCD (Minimum Covariance Determinant) estimator is shown to be adequate for this purpose. A major asset of the method that it can rely on existing DIF indices to define the DIF vectors, and that it does not need a purification step. Alternatively, it can be used to determine on an anchor set. The method will be illustrated by an example about calculator effects on mathematics test items. [less ▲]

Detailed reference viewed: 37 (2 ULg)
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See detailAn outline of a regional forest inventory in Belgium
Rondeux, Jacques ULg

in Mitteilungen der Abteilung für forstliche Biometrie (1985)

This paper outlines the first forest inventory recently carried out in the Southern part of Belgium (Wallonia) where the forests cover about 530.000 hectares (or 33 % of the regional area). The main ... [more ▼]

This paper outlines the first forest inventory recently carried out in the Southern part of Belgium (Wallonia) where the forests cover about 530.000 hectares (or 33 % of the regional area). The main objective was to estimate the standing volume of timber in the present conditions and to give, quickly, information dealing with the areas occupied according to different classifications. The inventory system used is based on temporary systematic sampling with an intensity of one plot per 50 hectares. [less ▲]

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See detailOutline of ULg chemical sensors applications for IAQ evaluation
Romain, Anne-Claude ULg

Conference (2014, December 04)

The arrival of the European and National laws* concerning the official labelling of building materials (CE marking) and the respect of concentration values for some compounds regulations in public ... [more ▼]

The arrival of the European and National laws* concerning the official labelling of building materials (CE marking) and the respect of concentration values for some compounds regulations in public buildings as for instance schools, the emergence of the Environmental Assessments of buildings (Breeam, HQE,…) beside the energy performance, as well as the awareness increase of the impact of indoor air quality on the wellness and health (ie ENVIE and Healthvent projects [1]) lead inevitably to the development of new sensing technologies related to the IAQ evaluation. Among the numerous existing measurement devices, electrochemical cells, NDIR and PID ones are the most encountered sensors on the market. The major uses are real time monitoring (CO2) and “friendly” handheld devices. Other applications are also studied in several research labs. Few years ago, the ULg research team investigated the interest of MOS chemical sensors arrays for IAQ evaluation. This presentation aims to review some of the results of those projects. A first is the fast and simple diagnosis of moulds on building materials. The identification of contaminated materials among uncontaminated ones was successful [2-4]. However, the low concentration of the MVOC markers compounds (below 10 µg/m³) and the complexity of the background (material emissions, and VOC content of the indoor air) curbed the use of MOS sensors. Specific preconcentrations have to be developed to improve the diagnosis. Nowadays, with the emergence of new sensing materials and new measurement principles (eg IMS-ion mobility spectrometry [5]), perspectives are again opened. Another project (HEMICPD, Belgian project “Horizontal evaluation method for the implementation of the Construction Products Directive”-Emissions to indoor air [6]) concerned the marking of building materials and one of the tasks was to test the sensors array principle to monitor the compounds emanation from different building material, during 28 days, in emission test chambers. Another goal was to investigate a classification of the materials including their odour level. The results on the use of sensors to evaluate the efficiency of “masking” products pulverised in wallpapers and to manage their use are also explained. [less ▲]

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See detailOutlook of non operated type B aortic dissection with special reference to the incidence of degenerative abdominal aortic aneurysm (AAA). One center study
Quaniers, Janine ULg; CREEMERS, Etienne ULg; Limet, Raymond ULg

in Acta Chirurgica Belgica (2005), 105(5), 487-490

Objectives : to determine the value of pharmacological treatment of type B aortic dissection (B AD) in face of new forms of treatment. Design : this is a retrospective study of the period from 1990 to ... [more ▼]

Objectives : to determine the value of pharmacological treatment of type B aortic dissection (B AD) in face of new forms of treatment. Design : this is a retrospective study of the period from 1990 to 2000. Files of 81 patients have been reviewed and completed by questionnaires. Results Two B AD died after admission without any treatment, 10 were operated on with 7 discharged alive (group 1) 69 received hypotensive agents and beta-blockers, 65 were discharged alive (group 11). Late mortality of the group I is 3/7, not related with B AD. Late mortality after mean follow-up of 56.8 months is 27/65 with 4/27 related to B AD (4 ruptures, 2 operated on). Non fatal secondary surgery amounts 5 in 4 patients. Total B AD aortic events comprise 8/65 patients. Type A AD were operated on successfully (8 : 4 before B AD, and 4 after B AD). Degenerative abdominal aortic aneurysms were present, operated (9) or not (3), in the history of patients and 3 more appear subsequently. At 10 years, actuarial survival is 40% +/- 18. Conclusion : in non-complicated cases of B AD, medical treatment is a reasonable choice, provided that a strict follow-up of the thoracic abdominal aorta is performed. [less ▲]

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See detailOutpatient and home parenteral antibiotic therapy (OHPAT) in low-risk febrile neutropenia: consensus statement of a Belgian panel.
Beguin, Yves ULg; Benoit, Yves; Crokaert, F. et al

in Acta Clinica Belgica (2002), 57(6), 309-16

Febrile neutropenia requires adequate antibiotic treatment. A subgroup of patients are only at low risk for complications and could be treated at home/as outpatients (OHPAT) after a short initial ... [more ▼]

Febrile neutropenia requires adequate antibiotic treatment. A subgroup of patients are only at low risk for complications and could be treated at home/as outpatients (OHPAT) after a short initial admission for work up. This position paper by a Belgian panel of experts presents criteria defining low-risk in febrile neutropenia, gives an overview of the existing experience and examines the present obstacles to a more widespread use of OHPAT in this country. [less ▲]

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See detailOutplacement adequacy and benefits: The mediating role of overall justice.
Marzucco, Laurence ULg; Hansez, Isabelle ULg

in Journal of Employment Counseling (in press)

Despite a rapid growth and an ongoing need for outplacement services, little is yet known about the perceived adequacy and benefits of these services for redundant employees using them. We surveyed 360 ... [more ▼]

Despite a rapid growth and an ongoing need for outplacement services, little is yet known about the perceived adequacy and benefits of these services for redundant employees using them. We surveyed 360 Belgian redundant employees (i.e., clients) using outplacement services provided by a public employment agency. The results indicate that an outplacement experience perceived as adequate for clients fosters their overall impressions of justice towards the dismissing organization; this leads in turn to benefits for them: reduction of negative emotions, enhancement of their perceived well-being, future perspectives, and job-seeking activities - confirming the mediating role of overall justice. [less ▲]

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See detailOutplacement adequacy and benefits: The mediating role of retrospective justice
Marzucco, Laurence ULg; Hansez, Isabelle ULg

Poster (2014, May)

ABSTRACT We examined the relationships between perceived outplacement adequacy, retrospective justice and outplacement benefits for redundant employees using outplacement services. Based on an ... [more ▼]

ABSTRACT We examined the relationships between perceived outplacement adequacy, retrospective justice and outplacement benefits for redundant employees using outplacement services. Based on an outplacement experience perceived as adequate, victims formed retrospective justice perceptions about their former organization that in turn, impacted their negative emotions, well-being, future perspectives and job search. PRESS PARAGRAPH The increasing prevalence of organizational downsizing has been matched by growth in the provision of outplacement services over the last decade. Despite this rapid growth and ongoing need for outplacement services, little is yet known about the perceived adequacy and the benefits of these services for redundant employees using them. Our results indicated that an outplacement experience perceived as adequate for redundant employees retrospectively fosters their impressions of justice about the dismissing organization; this leads in turn to satisfactory benefits for them: reduction of negative emotions, enhancement of their perceived well-being, future perspectives, and job-seeking activities. [less ▲]

Detailed reference viewed: 74 (2 ULg)
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See detailOutput-only modal analysis using blind source separation techniques
Poncelet, Fabien ULg; Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg et al

in Mechanical Systems & Signal Processing (2007), 21(6), 2335-2358

The present study carries out output-only modal analysis using two blind source separation (BSS) techniques, namely independent component analysis and second-order blind identification. The concept of ... [more ▼]

The present study carries out output-only modal analysis using two blind source separation (BSS) techniques, namely independent component analysis and second-order blind identification. The concept of virtual source is exploited and renders the application of these BSS techniques possible. The proposed modal analysis method is illustrated using numerical and experimental examples. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailAn outreach experience
Nazé, Yaël ULg

in European Planetary Science Congress 2006 (2006)

In our technological world, Science is everywhere and to participate to the public debates, citizens will need some basic scientific notions. Raising awareness of the public in Science is thus always ... [more ▼]

In our technological world, Science is everywhere and to participate to the public debates, citizens will need some basic scientific notions. Raising awareness of the public in Science is thus always worthwhile, even though only a small fraction of the audience will envisage a career in the field. Bringing science to the layman should even be a duty for scientists: we should not forget that we are paid by taxpayers, and are part of a public service; and besides, people tend to reject things that they do not understand - to get support, scientists need to enter the public arena and confront the crowd. Relying on attractive images and a timeless fascination, astronomy is particularly suited to do that. But what should a willing astronomer do to share (his/her) knowledge? There is certainly no definitive answer for that, but a few hints can still be given. Based on personal experience, this talk will present a few tips and things to avoid in three cases: animations (for kids and grown-ups), writing, and talking. [less ▲]

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See detailOutreach goals of the Europa Jupiter System Mission
Blanc, M.; Coustenis; Nazé, Yaël ULg et al

Poster (2009)

Detailed reference viewed: 12 (0 ULg)
See detailOutsider Science Fiction or the mainstreamisation of a genre
Guesse, Carole ULg

Conference (2015, February 04)

Detailed reference viewed: 13 (0 ULg)
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See detailLes outsiders, ou le retour de la norme : à propos des Goncourt francophones
Provenzano, François ULg

in Discours social (2008), XXX

Detailed reference viewed: 21 (1 ULg)
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See detailOutskirts Dynamics and new Residential Developments in Belgium. A comparative Analysis with the Swiss and Danish Contexts
Halleux, Jean-Marie ULg

in Franzen, M.; Halleux, Jean-Marie (Eds.) European Cities, Insight on Outskirts. Dynamics (2004)

Detailed reference viewed: 60 (11 ULg)
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See detailOutskirts Dynamics: towards Order or Chaos ?
Franzen, M.; Halleux, Jean-Marie ULg

in Franzen, M.; Halleux, Jean-Marie (Eds.) European Cities, Insight on Outskirts. Dynamics (2004)

Detailed reference viewed: 8 (0 ULg)
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See detailOutskirts, Accessibility and Chain Reactions within the Urban Field. The Dynamics of the Released Mobility
Halleux, Jean-Marie ULg

in Franzen, M.; Halleux, Jean-Marie (Eds.) European Cities, Insight on Outskirts. Dynamics (2004)

Detailed reference viewed: 15 (1 ULg)