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See detailIntroduction
Gauvry, Charlotte ULg

in Brisart, Robert; Gauvry, Charlotte (Eds.) Concept et perception. Le conceptualisme en question (2015)

Introduction au volume

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See detailAcoustic monitoring of O2 production of a seagrass meadow
Felisberto, Paulo; Jesus, Sérgio M.; Zabel, Friedrich et al

in Journal of Experimental Marine Biology and Ecology (2015), 464(0), 75-87

Acoustic data were acquired in October 2011 over a Posidonia oceanica meadow in the Bay of la Revellata, Calvi, Corsica. The purpose was to develop an acoustic system for monitoring the oxygen (O2 ... [more ▼]

Acoustic data were acquired in October 2011 over a Posidonia oceanica meadow in the Bay of la Revellata, Calvi, Corsica. The purpose was to develop an acoustic system for monitoring the oxygen (O2) production of an entire seagrass meadow. In a shallow water area (b38 m), densely covered by P. oceanica, a sound source transmitted signals in 3 different bands (400–800 Hz, 1.5–3.5 kHz and 6.5–8.5 kHz) toward three self-recording hydrophones at a distance of 100 m, over the period of oneweek. The data showa high correlation between the diel cycle of the acoustic signals' energy received by the hydrophones and the temporal changes in water column O2 concentration as measured by optodes. The results thus show that a simple acoustic acquisition system can be used to monitor the O2-based productivity of a seagrass meadow at the ecosystem level with high temporal resolution. The finding of a significant production of O2 as bubbles in seagrass ecosystems suggests that net primary production is underestimated by methods that rely on the mass balance of dissolved O2 measurements. [less ▲]

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See detailAnalytic solution for the relative motion of satellites in near-circular low-Earth orbits
Martinusi, Vladimir ULg; Dell'Elce, Lamberto ULg; Kerschen, Gaëtan ULg

in Proceedings of the AAS/AIAA Space FLight Mechanics Meeting (2015)

The paper presents the solution to the problem of the relative motion between two satellites orbiting Earth under the influence of the oblateness and atmospheric drag perturbations. Starting from the ... [more ▼]

The paper presents the solution to the problem of the relative motion between two satellites orbiting Earth under the influence of the oblateness and atmospheric drag perturbations. Starting from the analytic solution to the problem of the absolute motion, the closed-form equations of motion are obtained. No simplifying assumptions are made on the relative dynamics. [less ▲]

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See detailUn partenariat pour promouvoir la biodiversité dans les carrières belges
Harzé, Mélanie ULg; Lussis, Benoît; Boisson, Sylvain ULg et al

Conference (2015)

Plus que toute autre industrie, les carrières entretiennent un lien étroit avec les écosystèmes. L’exploitation d’une carrière crée des conditions abiotiques propices au développement d’une mosaïque ... [more ▼]

Plus que toute autre industrie, les carrières entretiennent un lien étroit avec les écosystèmes. L’exploitation d’une carrière crée des conditions abiotiques propices au développement d’une mosaïque d’habitats comme les falaises et arènes rocheuses, les plans d’eau temporaires ou les pelouses pionnières, favorables à certaines espèces protégées en Europe comme le hibou grand-duc et le crapaud calamite. Nombre d’entre eux sont d’intérêt communautaire et sont devenus rares dans le Nord de l’Europe. Ces habitats temporaires s’installent souvent spontanément pendant l’exploitation d’une carrière mais une action conservatoire peut s’avérer nécessaire pour leur conservation sur le long terme. En fin de vie de la carrière une restauration écologique adéquate pourra favoriser l’installation de milieux plus permanents d’intérêt. Afin de promouvoir le développement de cette biodiversité, une planification réfléchie des plans d’exploitation et de réhabilitation est nécessaire. La fédération des industries extractives belge FEDIEX s’est engagée en 2012 avec la Région wallonne dans une charte sectorielle « carrières et biodiversité », définissant un plan d’action basé sur trois axes principaux : (1) la sensibilisation des membres ; (2) la diffusion de recommandations pratiques pour intégrer la protection et la gestion de la biodiversité dans les plans l’exploitation ; (3) la formation du personnel des carrières. Dans ce cadre, l’unité Biodiversité et paysage de la Faculté de Gembloux Agro-Bio Tech (Université de Liège) collabore depuis 2012 avec la FEDIEX. Notre présentation portera sur les réalisations de cette collaboration ; notamment les formations « Carrières et Biodiversité » organisées à l’attention du secteur carrier, les résultats des actions concrètes mise en place en carrière, les documents de vulgarisation réalisés afin de donner aux gestionnaires les clés pour gérer et restaurer différents habitats et espèces protégées et notre collaboration à la rédaction d’un projet LIFE Biodiversity «LIFE in quarries » qui a été présenté à l’union européenne. [less ▲]

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See detailHigh strength steel in seismic resistant building frames (HSS-SERF)
Dubina, Dan; Vulcu, Cristian; Stratan, Aurel et al

Book published by Commission Européenne (2015)

The aim of “HSS-SERF” project was to investigate and evaluate the seismic performance of dual-steel building frames, realized from two different steel grades: Mild Carbon Steel (MCS) and High Strength ... [more ▼]

The aim of “HSS-SERF” project was to investigate and evaluate the seismic performance of dual-steel building frames, realized from two different steel grades: Mild Carbon Steel (MCS) and High Strength Steel (HSS). A comprehensive set of dual-steel frames (moment resisting, concentrically and eccentrically braced) were designed, which allowed the identification of realistic member sizes for both MCS and HSS components. Several practical solutions for bolted and welded beam-to-column joints were identified and designed. Further, an extensive numerical program was carried out for the seismic performance evaluation of frames. The ductility and over-strength demands, and q-factors associated with different performance levels were evaluated. Furthermore, experimental and numerical investigations were carried out on joint assemblies and components. Guidelines were elaborated for the conceptual design and PBD of dual-steel frames under seismic actions, and the technical and economic efficiency of dualsteel structures vs. conventional ones were finally evaluated. The main outcomes of the project consist in: (i) development and characterisation in terms of global ductility and over-strength demands of dual-steel frames with composite columns (innovative solutions in European context); (ii) development of design recommendations; (iii) proposal of innovative solutions for beam-to-column joints with composite columns; (iv) recommendation for weld details and appropriate component method design approaches; (v) evaluation of technical and economic efficiency of the dual-steel approach. [less ▲]

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See detailThe range of validity of sorption kinetic models
Douven, Sigrid ULg; Pàez Martinez, Carlos ULg; Gommes, Cédric ULg

in Journal of Colloid & Interface Science (2015), 448

Several hundred papers are published yearly reporting liquid-phase adsorption kinetics data. In general the data is analyzed using a variety of standard models such as the pseudo first- and second-order ... [more ▼]

Several hundred papers are published yearly reporting liquid-phase adsorption kinetics data. In general the data is analyzed using a variety of standard models such as the pseudo first- and second-order models and the Intraparticle-Diffusion model. The validity of these models is often assessed empirically via their ability to fit the data, independently of their physicochemical soundness. The aim of the present paper is to rationalize the analysis of liquid-phase adsorption kinetics data, and to investigate experimental factors that influence the adsorption kinetics, in addition to the characteristics of the adsorbent material itself. For that purpose we use a simple Langmuir adsorption–diffusion model, which enables us to identify three dimensionless numbers that characterize the working regime of any batch adsorption experiment: an adsorption Thiele modulus, a saturation modulus, and a loading modulus. The standard models are found to be particular cases of the general adsorption–diffusion model for specific values of the dimensionless numbers. This provides sound physicochemical criteria for the validity of the models. Based on our modeling, we also propose a general yet simple data analysis procedure to practically estimate the diffusion coefficient in adsorbent pellets starting from adsorption halftimes. [less ▲]

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See detailIntratumoral heterogeneity and consequences for targeted therapies
Turtoi, Andrei ULg; Blomme, Arnaud ULg; Castronovo, Vincenzo ULg

in Bulletin du Cancer (2015), 102(1), 17-23

According to the clonal model and Darwinian evolution, cancer cell evolves through new mutations helping it to proliferate, migrate, invade and metastasize. Recent genetic studies have clearly shown that ... [more ▼]

According to the clonal model and Darwinian evolution, cancer cell evolves through new mutations helping it to proliferate, migrate, invade and metastasize. Recent genetic studies have clearly shown that tumors, when diagnosed, consist of a large number of mutations distributed in different cells. This heterogeneity translates in substantial genetic plasticity enabling cancer cells to adapt to any hostile environment. As targeted therapy focuses only on one pathway or protein, there will always be a cell with the "right" genetic background to survive the treatment and cause tumor relapse. Because today's targeted therapies never took tumor heterogeneity into account, nearly all novel drugs fail to provide patients with a considerable improvement of the survival. However, emerging proteomic studies guided by the idea that Darwinian selection is governed by the phenotype and not genotype, show that heterogeneity at the protein level is much less complex, then it could be expected from genetic studies. This information together with the recent trend to switch from functional to cytotoxic targeting may offer an entirely new strategy to efficiently combat cancer. [less ▲]

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See detailDes bandes urbaines en Belgiques?
Collin, Jonathan ULg

Conference given outside the academic context (2015)

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See detailThe alpha2,3-Sialyltransferase Encoded by Myxoma Virus Is a Virulence Factor that Contributes to Immunosuppression.
Boutard, Berengere; Vankerckhove, Sophie; Markine-Goriaynoff, Nicolas et al

in PloS one (2015), 10(2), 0118806

Myxoma virus (MYXV) induces a lethal disease called Myxomatosis in European rabbits. MYXV is one of the rare viruses that encodes an alpha2,3-sialyltransferase through its M138L gene. In this study, we ... [more ▼]

Myxoma virus (MYXV) induces a lethal disease called Myxomatosis in European rabbits. MYXV is one of the rare viruses that encodes an alpha2,3-sialyltransferase through its M138L gene. In this study, we showed that although the absence of the enzyme was not associated with any in vitro deficit, the M138L deficient strains are highly attenuated in vivo. Indeed, while all rabbits infected with the parental and the revertant strains died within 9 days post-infection from severe myxomatosis, all but one rabbit inoculated with the M138L deficient strains survived the infection. In primary lesions, this resistance to the infection was associated with an increased ability of innate immune cells, mostly neutrophils, to migrate to the site of virus replication at 4 days post-infection. This was followed by the development of a better specific immune response against MYXV. Indeed, at day 9 post-infection, we observed an important proliferation of lymphocytes and an intense congestion of blood vessels in lymph nodes after M138L knockouts infection. Accordingly, in these rabbits, we observed an intense mononuclear cell infiltration throughout the dermis in primary lesions and higher titers of neutralizing antibodies. Finally, this adaptive immune response provided protection to these surviving rabbits against a challenge with the MYXV WT strain. Altogether, these results show that expression of the M138L gene contributes directly or indirectly to immune evasion by MYXV. In the future, these results could help us to better understand the pathogenesis of myxomatosis but also the importance of glycans in regulation of immune responses. [less ▲]

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See detailNederlands-Frans in contrast. 2000 lexicologische valstrikken in het Frans voor Nederlandstaligen
Theissen, Siegfried ULg; Hiligsmann, Philippe; Rasier, Laurent ULg et al

Book published by Acco (2015)

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See detailDetermination of arsenic (III) at a nano gold modified solid carbon paste electrode
Sakira, Abdoul Karim; Somé, Issa Touridomon; Ziemons, Eric ULg et al

in Electroanalysis (2015), 27

A selective and sensitive electroanalytical method was developed for arsenic determination based on a nanogold (AuNP) modified solid carbon paste work- ing electrode (SCPE) modified in two steps (i ... [more ▼]

A selective and sensitive electroanalytical method was developed for arsenic determination based on a nanogold (AuNP) modified solid carbon paste work- ing electrode (SCPE) modified in two steps (i) physisorp- tion and (ii) additional electrodeposition of nanogold par- ticles in the presence of iodide. Copper(II) interference was solved by covering the gold layer by a self assembled mono layer (SAM) of glutathione. Using DPASV a linear response of the signal was obtained as a function of As(III) in the concentration range 0.05–20mM (4– 1498 ppb) with a limit of detection of 0.01 mM (0.9 ppb). Sample stirring and degassing were not needed. Applica- tion to the determination of arsenic(III) and (V) in un- derground water samples from Burkina Faso was success- fully achieved. [less ▲]

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See detailAdventitious organogenesis induced in sweet orange (Citrus sinensis L.) var. "half-blood" maltese: morphogenetic and histological study
Benmahmoud, Kaouther; Jedidi, Zmna; Najar, Asma et al

in International Journal of Agronomy and Agricultural Research (2015), 6(2), 1-7

Tunisian citrus crops are faced to several abiotic and biotic constraints among which virus and virus-like diseases are incurable. The production of virus-free plants systematically needs the use of in ... [more ▼]

Tunisian citrus crops are faced to several abiotic and biotic constraints among which virus and virus-like diseases are incurable. The production of virus-free plants systematically needs the use of in vitro techniques. In this context, somatic embryogenesis and further plantlet regeneration of the Tunisian “half-blood” Maltese orange were obtained using explants consisting in style/stigma collected from unopened flowers. Somatic embryos were induced on Murashige and Skoog medium containing 13.3 µM 6-benzylaminopurine and 500 mg.l-1 malt extract, but their germination was obtained on hormone free-medium. Somatic embryogenesis was induced indirectly from intermediate friable callus initiated at the basal part of the style. Somatic embryos exhibited central procambial cells and were surrounded by a protoderm isolating them from the callus. These embryos had bipolar structure confirmed by the presence of shoot and root apices at cotyledonary stage. The use of cotyledon excised from those embryos failed to regenerate somatic embryos, but gave rise to direct organogenesis in two forms, true buds and protuberances both evolved in shoots after transfer in hormone-free medium. According to histological observations, protuberances are induced from epidermal and subepidermal cells of the cotyledon explant and remain closely attached to their mother tissue even at the shoot stage. [less ▲]

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See detailSolar Energy Prediction: An International Contest to Initiate Interdisciplinary Research on Compelling Meteorological Problems
McGovern, Amy; Gagne II, David John; Eustaquio, Lucas et al

in Bulletin of the American Meteorological Society [= BAMS] (2015)

As meteorological observing systems and models grow in complexity and number, the size of the data becomes overwhelming for humans to analyze using traditional techniques. Computer scientists, and ... [more ▼]

As meteorological observing systems and models grow in complexity and number, the size of the data becomes overwhelming for humans to analyze using traditional techniques. Computer scientists, and specifically machine learning and data mining researchers, are developing frameworks for analyzing big data. The AMS Committee on Artificial Intelligence and its Applications to Environmental Science aims to bring AI researchers and environmental scientists together to increase the synergy between the two. The AI committee has sponsored 4 previous contests on a variety of meteorological problems including wind energy, storm classification, winter hydrometeor classification, and air pollution, with the goal of bringing together the two fields of research. Although these were successful, the audience was limited to existing environmental science researchers (usually 10-20 teams of people primarily within the AMS community). For the 2013/14 contest, we expanded to a global audience by focusing on the compelling problem of solar energy prediction and by having the established forum Kaggle host our contest. Using this forum, we had over 160 teams from all around the world participate. Improved solar energy forecasting is a necessary component of making solar energy a viable alternative power source. This paper summarizes our experiences in the 2013/14 contest, discusses the data in detail, and presents the winning prediction methods. The contest data come from the NOAA/ESRL Global Ensemble Forecasting System Reforecast Version 2 and the Oklahoma Mesonet with sponsorship from EarthRisk Technologies. All winning methods utilized gradient boosted regression trees but differed in parameter choices and interpolation methods. [less ▲]

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See detailSolutrean and Magdalenian ferruginous rocks heat-treatment: accidental and/or deliberate action?
Salomon, Hélène ULg; Vignaud, Colette; Lahlil, Sophia et al

in Journal of Archaeological Science (2015), 55

Heating of prehistoric coloring materials can induce radical changes in color indicative of structural matter transformation. For instance, the structure of the yellow iron oxide-rich mineral, goethite ... [more ▼]

Heating of prehistoric coloring materials can induce radical changes in color indicative of structural matter transformation. For instance, the structure of the yellow iron oxide-rich mineral, goethite, changes into the red iron oxide-rich mineral, hematite, when it is heated to around 250-300°C. For a long time, heating has been thought to be the reason for the high frequencies of red rocks used in camp sites and the red pigments in rock art paintings. However, records of heat-treatment of coloring materials are usually not well documented; the contextual information is not clear enough to confirm intentional heating. Two Solutrean camp sites (the flint workshop Les Maîtreaux and the hunting site Combe Saunière I) and one middle Magdalenian cave with rock art (Grotte Blanchard, La Garenne) allow us to study the heating process of ferruginous rocks. All three sites, which have been excavated relatively recently, have well-defined archaeological records and strong associations between the ferruginous rocks and other artifacts. With the use of X-ray diffraction and electron µ-diffraction for identifying structural modification and SEM-FEG and TEM-FEG for detecting dehydration nano-pores, we have strong evidence for intentional heat-treatment of yellow goethite-rich materials in two archaeological contexts and one site for unintentional heating, where rocks were only partially transformed. Intentional heating to obtain red hematite from primary goethite would have required ingenious methods of temperature control in fireplace settings and purpose-built ground ovens. [less ▲]

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See detailSupervised inference of biological networks with trees : Application to genetic interactions in yeast
Schrynemackers, Marie ULg

Doctoral thesis (2015)

Networks or graphs provide a natural representation of molecular biology knowledge, in particular to model relationships between biological entities such as genes, proteins, drugs, or diseases. Because of ... [more ▼]

Networks or graphs provide a natural representation of molecular biology knowledge, in particular to model relationships between biological entities such as genes, proteins, drugs, or diseases. Because of the effort, the cost, or the lack of the experiments necessary to the elucidation of these networks, computational approaches for network inference have been frequently investigated in the literature. In this thesis, we focus on supervised network inference methods. These methods exploit supervised machine learning algorithms to train a model for identifying new interacting pairs of nodes from a training sample of known interacting and possibly non-interacting pairs and additional measurement data about the network nodes. Our contributions in this area are divided into three parts. First, the thesis examines the problem of the assessment of supervised network inference methods. Indeed, their reliable validation (in silico) poses a number of new challenges with respect to standard classification problems, related to the fact that pairs of objects are to be classified and to the specificities of biological networks. We perform a critical review and assessment of protocols and measures proposed in the literature. Through theoretical considerations and in silico experiments, we analyze in depth how important factors influence the outcome of performance estimation. These factors include the amount of information available for the interacting entities, the sparsity and topology of biological networks, and the lack of experimentally verified non-interacting pairs. From this analysis, we derived specific guidelines so as to how best exploit and evaluate machine learning techniques for network inference. Second, we systematically investigate, theoretically and empirically, the exploitation of tree- based methods for network inference. We consider these methods in the context of the two main generic classification-based approaches for network inference: the local approach, which trains a separate model for each network node, and the global approach, which trains a single model over pairs of nodes. We present and formalize these two approaches, extending the former for the prediction of interactions between two unseen network nodes, and discuss their specializations to tree-based methods, highlighting their interpretability and drawing links with clustering techniques. Extensive experiments are carried out with these methods on various biological networks that clearly highlight that these methods are competitive with existing methods. The interpretability of the resulting method family is illustrated on a drug-protein interaction network. In the last part of the thesis, we built on the experience gained in the two previous parts to try to predict at best the genetic interaction network in yeast S.cerevisiae. For that purpose, we collected a large dataset, assembling 4 millions gene pairs that were experimentally tested in the context of 11 different studies and 23 sets of measurements to use as gene input features for the inference. Through several cross-validation experiments on the resulting dataset, we showed that predicting genetic interactions is indeed possible to some useful extent and that actually in some settings, the accuracy of computational methods is not very far from that of experimental techniques. [less ▲]

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See detailAnalyzing Access, Egress, and Main Transport Mode of Public Transit Journeys: Evidence from the Flemish National Household Travel Survey
Creemers, Lieve; Bellemans, Tom; Janssens, Davy et al

in Proceedings of the 94th Annual Meeting of the Transportation Research Board (2015)

The primary objective of this paper is to explore the influence of socio-demographic and contextual variables on the multimodal character of public transit journeys. Accounting for multimodality in public ... [more ▼]

The primary objective of this paper is to explore the influence of socio-demographic and contextual variables on the multimodal character of public transit journeys. Accounting for multimodality in public transit journeys is important from a demand modeling point of view, especially in the assessment of new projected public transit infrastructure. To meet the objective, data from the national household travel survey of Flanders (Belgium) is analyzed. Based on 2,202 public transit journeys, the main public transit mode choice (bus/tram/metro or train) and access/egress mode choice are simultaneously estimated using a multinomial logit model, and by explicitly making a distinction between unimodal and multimodal transit journeys. The results indicate that various socio-demographical (e.g. age, gender, level of education, household income) and contextual factors (e.g. journey distance, journey motive, urbanization degree, car availability) significantly influence the joint decision process. Total journey distance and car availability are identified as the most important explanatory variables. In terms of model performance, the model appears to yield satisfactory predictions, justifying the integration of the model in more general demand modeling frameworks. [less ▲]

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See detailPredicting biomass and grain protein content using Bayesian methods
Mansouri, Majdi ULg; Destain, Marie-France ULg

in Stochastic Environmental Research & Risk Assessment (2015)

This paper deals with the problem of predicting biomass and grain protein content using improved particle filtering (IPF) based on minimizing the Kullback–Leibler divergence. The performances of IPF are ... [more ▼]

This paper deals with the problem of predicting biomass and grain protein content using improved particle filtering (IPF) based on minimizing the Kullback–Leibler divergence. The performances of IPF are compared with those of the conventional particle filtering (PF) in two comparative studies. In the first one, we apply IPF and PF at a simple dynamic crop model with the aim to predict a single state variable, namely the winter wheat biomass, and to estimate several model parameters. In the second study, the proposed IPF and the PF are applied to a complex crop model (AZODYN) to predict a winter-wheat quality criterion, namely the grain protein content. The results of both comparative studies reveal that the IPF method provides a better estimation accuracy than the PF method. The benefit of the IPF method lies in its ability to provide accuracy related advantages over the PF method since, unlike the PF which depends on the choice of the sampling distribution used to estimate the posterior distribution, the IPF yields an optimum choice of this sampling distribution, which also utilizes the observed data. The performance of the proposed method is evaluated in terms of estimation accuracy, root mean square error, mean absolute error and execution times. [less ▲]

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See detailTiO2 Macroscopic Fibers with Enhanced Photocatalytic Properties Obtained through a Scale-Up Semi-Industrial Process
Kinadjian, Natacha; Le Bechec, Mickael; Henrist, Catherine ULg et al

in Advanced Engineering Materials (2015), 17(1), 36-44

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See detailBayesian inference for transportation origin–destination matrices: the Poisson–inverse Gaussian and other Poisson mixtures
Perrakis, Konstantinos; Karlis, Dimitris; Cools, Mario ULg et al

in Journal of the Royal Statistical Society. Series A Statistics in Society (2015), 178(1), 271-296

Transportation origin–destination analysis is investigated through the use of Poisson mixtures by introducing covariate-based models which incorporate different transport modelling phases and also allow ... [more ▼]

Transportation origin–destination analysis is investigated through the use of Poisson mixtures by introducing covariate-based models which incorporate different transport modelling phases and also allow for direct probabilistic inference on link traffic based on Bayesian predictions. Emphasis is placed on the Poisson–inverse Gaussian model as an alternative to the commonly used Poisson–gamma and Poisson–log-normal models. We present a first full Bayesian formulation and demonstrate that the Poisson–inverse Gaussian model is particularly suited for origin–destination analysis because of its desirable marginal and hierarchical properties. In addition, the integrated nested Laplace approximation is considered as an alternative to Markov chain Monte Carlo sampling and the two methodologies are compared under specific modelling assumptions. The case-study is based on 2001 Belgian census data and focuses on a large, sparsely distributed origin–destination matrix containing trip information for 308 Flemish municipalities. [less ▲]

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