Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
See detailPrediction of the reverberation time in rooms with non uniform absorptions using a diffusion model
Billon, Alexis ULg; Sakout, Anas

Conference (2006, July)

The acoustical comfort is now a comfort’s criterion which is taken into from the conception. The designers need therefore accurate tools to predict the acoustic quality of enclosures. Most of the ... [more ▼]

The acoustical comfort is now a comfort’s criterion which is taken into from the conception. The designers need therefore accurate tools to predict the acoustic quality of enclosures. Most of the acoustical comfort criteria are based on the reverberation time. When the room has proportionate dimensions and an uniform absorption, the statistical theory through Sabine or Eyring formulas allows good predictions of the reverberation time. Moreover, extensions of these relations by Millington or Cremer and Müller among others give quite satisfactory when the room is composed of materials with different sound absorption. In this study, the reverberation time in an enclosure is calculated via the numerical resolution of unstationary diffusion equation, model validated in coupled and industrial rooms. Firstly, an improvement of the boundary condition is proposed for highly absorbent surfaces. The diffusion model is then compared to several formulations of the statistical theory and a ray-tracing software for a cubic room with homogeneous walls’ absorption and with non homogeneous walls’ absorptions. Finally, an experimental validation is conducted for an enclosure with non uniformly distributed absorption. [less ▲]

Detailed reference viewed: 49 (4 ULg)
Peer Reviewed
See detailPrediction of the Semi-Rigid and Partial-Strength Properties of Structural Joints
Jaspart, Jean-Pierre ULg; Maquoi, René ULg

in Proceedings of the SSRC Annual technical Session and Meeting (1994, June)

Detailed reference viewed: 55 (1 ULg)
Full Text
Peer Reviewed
See detailPrediction of the sound pressure levels using a diffusion model: numerical validations and experimental comparisons
Billon, Alexis ULg; Picaut, Judicaël

in Journal of the Acoustical Society of America (2008), 123(5), 3924-3924

redictions of sound propagation in urban areas have attracted a considerable over the years. If the sound energy is assimilated to particles with a constant energy, their movement can be described by a ... [more ▼]

redictions of sound propagation in urban areas have attracted a considerable over the years. If the sound energy is assimilated to particles with a constant energy, their movement can be described by a transport equation. In canyon streets, this transport equation can be reduced to a diffusion equation whose expression is more simple. In this presentation, sound absorption at the boundaries (buildings facades and ground), as well as atmospheric sound attenuation are introduced. The problem is then solved numerically using a finite elements method for the configuration of a canyon street. A systematic validation of the obtained model is carried out in terms of sound pressure level by comparison to numerical simulations taken from the literature. Comparisons with experimental data are then conducted. Finally, applications in more complex configurations are presented. [less ▲]

Detailed reference viewed: 43 (1 ULg)
Full Text
Peer Reviewed
See detailPrediction of the Tension/Compression asymmetry of ECAP processed FCC material using an integrated model based on dislocation and back-stress
Chen, Enze; Duchene, Laurent ULg; Habraken, Anne ULg et al

in Materials Science Forum (2011), 667-669

In our recent work, a new integrated model was proposed to describe the back-stress evolution based on the dislocation substructure and texture. By relating the back-stress to the dislocation density in ... [more ▼]

In our recent work, a new integrated model was proposed to describe the back-stress evolution based on the dislocation substructure and texture. By relating the back-stress to the dislocation density in cell walls and in the cell interior, this model is able to capture the back-stress evolution of ECAP processed pure aluminium. In this paper, the model is used for another FCC material, namely copper. The aim is to check whether this model is able to predict the tension/compression asymmetry (due to the back-stress) of copper. The results show that this is indeed the case and it is also found that the strain rate ratio proposed in our previous work [1] is a function of the dislocation density ratio. [less ▲]

Detailed reference viewed: 30 (5 ULg)
Full Text
Peer Reviewed
See detailPrédiction structurée multitâche itérative de propriétés structurelles de protéines
Maes, Francis ULg; Becker, Julien ULg; Wehenkel, Louis ULg

in 7e Plateforme AFIA: Association Française pour l'Intelligence Artificielle (2011)

Le développement d'outils informatiques pour prédire de l'information structurelle de protéines à partir de la séquence en acides aminés constitue un des défis majeurs de la bioinformatique. Les problèmes ... [more ▼]

Le développement d'outils informatiques pour prédire de l'information structurelle de protéines à partir de la séquence en acides aminés constitue un des défis majeurs de la bioinformatique. Les problèmes tels que la prédiction de la structure secondaire, de l'accessibilité au solvant, ou encore la prédiction des régions désordonnées, peuvent être exprimés comme des problèmes de prédiction avec sorties structurées et sont traditionnellement résolus individuellement par des méthodes d'apprentissage automatique existantes. Etant donné que ces problèmes sont fortement liés les uns aux autres, nous proposons de les traiter ensemble par une approche d'apprentissage multitâche. A cette fin, nous introduisons un nouveau cadre d'apprentissage générique pour la prédiction structurée multitâche. Nous appliquons cette stratégie pour résoudre un ensemble de cinq tâches de prédiction de propriétés structurelles des protéines. Nos résultats expérimentaux sur deux jeux de données montrent que la stratégie proposée est significativement meilleure que les approches traitant individuellement les tâches. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
Peer Reviewed
See detailPredictions in overdispersed series of counts using an approximate predictive likelihood
Lambert, Philippe ULg

in Journal of Forecasting (1997), 16

The generalized autoregression model or GARM, originally used to model series of non-negative data measured at irregularly spaced time points (Lambert, 1996a), is considered in a count data context. It is ... [more ▼]

The generalized autoregression model or GARM, originally used to model series of non-negative data measured at irregularly spaced time points (Lambert, 1996a), is considered in a count data context. It is first shown how the GARM can be expressed as a GLM in the special case of a linear model for some transform of the location parameter. The Butler approximate predictive likelihood (Butler, 1986, Rejoinder) is then used to define likelihood prediction envelopes. The width of these intervals is shown to be slightly wider than the Fisher (1959, pp. 128-33) and Lejeune and Faulkenberry (1982) predictive likelihood-based envelopes which assume that the parameters have fixed known values (equal to their maximum likelihood estimates). The method is illustrated on a small count data set showing overdispersion. [less ▲]

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailPredictions of the reverberation time in high absorbent room using a modified-diffusion model
Billon, Alexis ULg; Picaut, Judicaël; Sakout, Anas

in Applied Acoustics (2008), 69(1), 68-74

A modification of the diffusion model’s boundary condition, based on the Eyring absorption coefficient, to account for high walls absorption is proposed. Numerical comparisons are carried out for three ... [more ▼]

A modification of the diffusion model’s boundary condition, based on the Eyring absorption coefficient, to account for high walls absorption is proposed. Numerical comparisons are carried out for three geometrical configurations (a proportionate room, a corridor and a flat enclosure). Comparisons with the statistical theory and a ray-tracing software show that the modified boundary condition increases the accuracy of the diffusion model in term of reverberation time in all the simulated configurations. An experimental comparison in the case of a non-uniformly absorbent room (a reverberation chamber covered with patches of glass wool) is also carried out. The modified-diffusion model results match well with the ray-tracing ones. Both models are in agreement with the experimental data for most of third octave bands (discrepancy close to or below 10%). However, some discrepancies up to 40% can also be observed in a few octave bands, probably due to experimental considerations and to the modal behaviour of the room at low frequencies. [less ▲]

Detailed reference viewed: 29 (3 ULg)
Full Text
Peer Reviewed
See detailA predictive battery of literacy acquisition for children in third year kindergarten
Gillet, Sophie ULg; Binamé, Florence ULg; Martinetti, Julie et al

Poster (2014)

Detailed reference viewed: 12 (1 ULg)
See detailPredictive Design of Honeycomb Sandwich Panels
Assaker, Roger; Depouhon, Alexandre ULg; Botman, Jean-Pierre

in Proceedings of Sampe Benelux professional meetings (2008, November)

Detailed reference viewed: 16 (2 ULg)
Peer Reviewed
See detailPredictive factors for low back pain and associated sick leave in a cohort of young workers
VAN NIEUWENHUYSE, An; SOMVILLE, Pierre-René; MOENS, G. et al

(2006, June 11)

Detailed reference viewed: 10 (3 ULg)
Full Text
See detailPredictive factors for response of anemia to recombinant human erythropoietin
Beguin, Yves ULg

in Nowrousian, M. R. (Ed.) Recombinant human erythropoietin (rhEPO) in clinical oncology (2002)

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailPredictive factors in locally advanced rectal cancer treated with preoperative hyperfractionated and accelerated radiotherapy.
Bouzourene, H; Bosman, F; Matter, M et al

in Human Pathology (2003), 34(6), 541-548

This study examines the prognostic significance of pathologic factors in patients with primary locally advanced rectal cancer treated prospectively with preoperative radiotherapy. From 1992 to 1998, 104 ... [more ▼]

This study examines the prognostic significance of pathologic factors in patients with primary locally advanced rectal cancer treated prospectively with preoperative radiotherapy. From 1992 to 1998, 104 patients with rectal cancer of grades T3 or T4 and any N underwent preoperative radiotherapy followed by surgical resection. Survival curves were estimated according to the Kaplan-Meier method. Correlation of outcome with clinicopathologic variables (pathologic tumor and lymph node staging, histology, radial resection margin [RRM], clearance, vessel involvement, and tumor regression grade [TRG], quantitated in 5 grades) was evaluated using the Cox proportional hazards model. None of the patients achieved a histologically confirmed complete pathologic response, but 79% of the patients showed partial tumor regression (TRG2–4) and 21% did not show any tumor regression (TRG5). Among the tumors, 22% were of a mucinous type. The RRM was free of tumor in 76% of the surgical specimens. The median clearance was 2 mm. Vascular invasion was present in 37 cases (36%). In the univariate analysis, lymph node metastases, absence of tumor regression, positive RRM, and vascular invasion were correlated with adverse overall survival and diseasefree survival; absence of tumor regression, positive RRM, and clearance <2 mm were correlated with local recurrences; and advanced pT stage was correlated only with disease-free survival. However, in the multivariate analysis, only lymph node metastases and RRM were independent prognostic factors for overall survival and disease-free survival, and clearance <2 mm was an independent prognostic factor for local control. Pathologic parameters remain strong determinants of local recurrence and survival in locally advanced rectal cancer, treated preoperatively with hyperfractionated and accelerated radiotherapy. We show that patients with advanced pT, positive lymph nodes, vascular invasion, positive RRM, clearance <2 mm, or absence of tumor regression are known to have poor clinical outcome. HUM PATHOL 34:541-548. © 2003 Elsevier Inc. All rights reserved. Abbreviations: , computed tomography; DFS, disease-free survival; HART, hyperfractionated accelerated radiotherapy; OS, overall survival; RRM, radial resection margin; TRG, tumor regression grade. [less ▲]

Detailed reference viewed: 22 (4 ULg)
Full Text
See detailPredictive methods exploring sensory irritation to surfactant-based products.
Pierard, Gérald ULg; Preud'Homme, L.; QUATRESOOZ, Pascale ULg

in Household and Personal Care (2011), 7

Detailed reference viewed: 15 (1 ULg)
Full Text
Peer Reviewed
See detailPredictive microbiology combined with metagenomic analysis targeted on the 16S rDNA : A new approach for food quality
Delhalle, Laurent ULg; Taminiau, Bernard ULg; Ellouze, Mariem et al

in Ellouze, Mariem; Tenenhaus-Aziza, Fanny (Eds.) Proceedings of thge 8th International Conference on predictive microbiology in foods (ICPMF8) (2013, September 18)

OBJECTIVES The food spoilage process is mainly caused by alteration micro-organisms and classical culture-based methods have therefore been used to assess the microbiological quality of food. These ... [more ▼]

OBJECTIVES The food spoilage process is mainly caused by alteration micro-organisms and classical culture-based methods have therefore been used to assess the microbiological quality of food. These techniques are simple to implement but may not be relevant to understand the modifications of the microbial ecology which occur in the food product in response to different changes in the environmental conditions. Metagenomic analysis targeted on 16S ribosomal DNA can bring about a solution to this new need and elucidate microbial community structures, including the identification and quantification of culturable and non-culturable organisms, at a much higher resolution than was previously possible with culture-based methods to provide a picture of the microbial community. Combined with predictive microbiological models, a new approach was investigated to take into account the dynamics of the evolutions of the microbial community in food products. This work describes the application of a metagenomic analysis and predictive microbiology in order to study bacterial populations dynamics in perishable foods under different environmental conditions. METHODS White pudding samples, a typical Belgian pork meat product, were packed under food wrap (atmospheric air condition). Durability studies were conducted at 4°C, 12°C and a dynamic temperature profile according to the NF V01-003 standards (4°C (1/3 of the shelf life) - 8°C (2/3 of the shelf life)) during 15 days. The effect of organic acids was also investigated using a lactic acid / diacetic acid mix (1.8% w/w) treatment. At each day of the trials, classical microbiological (total flora, lactic acid bacteria) and 16S rDNA metagenomic analysis were carried out on all these samples. For the metagenomic analysis, a sequencing library was generated, targeting the V1-V3 region of the 16S rDNA. Libraries were sequenced on a GS junior sequencer using Titanium technology. The Bio- informatic pipeline using Mothur, Blast and Stamp was used to assign a taxonomical identity to the sequences and to obtain the bacterial population proportions of the samples (Schloss, Westcott et al. 2009). The major bacterial populations were thus identified and predictive microbiology models (Baranyi and Roberts 1994; Augustin, Zuliani et al. 2005) were used to assess the growth parameters. The model was validated using the data obtained at a dynamic temperature profile. RESULTS The metagenomic analysis of the samples shows that the bacterial populations from the day 0 sample to the post-shelf life sample have important modifications. Brochothrix and Psychrobacter were identified as the dominant flora. As expected, the storage temperature had a strong impact on the  bacterial evolutions. Moreover, the use of lactic acid/diacetic acid reveals the sensitivity of the different populations to the treatment. For the storage at 4°C, the initial dominance of Pseudomonas and Shewanella is slightly reduced during storage until shelf life, after which it drops to be replaced by Brochothrix and Psychrobacter. The addition of the preservation treatment has a statistical negative impact on the Psychrobacter and Acinetobacter populations. During the ageing assay (2 days at 4°C followed by 10 days at 8°C), the analysis underlines the influence of the temperature change on the onset of the Brochothrix and Psychrobacter dominance compared to the entire 4°C storage. Again, the preservation treatment delays this onset. Finally, at an abusive 12°C temperature, samples are quickly dominated by the Psychrobacter/Brochothrix pair after 2 days of storage. In this case, the lactic acid mix does not appear to be of any effective use. Adjustment of primary model was made on the major bacterial populations and simulation was made based on estimated growth rate. The simulations of the three major populations seem to be sufficient for this food product to predict 80 -90 % of the bacterial population at the end of the shelf life in function of the environmental conditions. CONCLUSIONS AND IMPACT OF THE STUDY Compared to culture based methods on selective media and previous independent culture techniques, metagenomic analysis combined with predictive microbiology gives more valuable information, and its use could be considered as a technique for quality control or for accurately determining shelf life. REFERENCES Augustin, J. C., V. Zuliani, et al. (2005). "Growth rate and growth probability of Listeria monocytogenes in dairy, meat and seafood products in suboptimal conditions." J Appl Microbiol 99(5): 1019-­‐1042. Baranyi, J. and T. A. Roberts (1994). "A dynamic approach to predicting bacterial growth in food." International Journal of Food Microbiology 23(3-­‐4): 277-­‐294. Schloss, P. D., S. L. Westcott, et al. (2009). "Introducing mothur: open-­‐source, platform-­‐independent, community-­‐supported software for describing and comparing microbial communities." Appl. Environ. Microbiol. 75(23): 7537-­‐7541. [less ▲]

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailPredictive microbiology combined with metagenomic analysis targeted on the 16S rDNA : A new approach for food quality
Delhalle, Laurent ULg; Ellouze, Mariem; Taminiau, Bernard ULg et al

Poster (2014, September 01)

The food spoilage process is mainly caused by alteration micro-organisms and classical culture-based methods may not be relevant to understand the modifications of the microbial ecology in food products ... [more ▼]

The food spoilage process is mainly caused by alteration micro-organisms and classical culture-based methods may not be relevant to understand the modifications of the microbial ecology in food products. Metagenomic analysis targeted on 16S ribosomal DNA can elucidate microbial community structures at a muche higher resolution than was previously possible. Combined with predictive microbiological models, a new approach was investigated to take into account bacterial populations dynamics in perishable foods under different environmental conditions. White pudding samples, a typical Belgian pork meat product, were packed under food wrap (atmospheric air condition). Durability studies were conducted at 4°C, 12°C and a dynamic temperature profile according to the NF V01-003 standards (4°C (1/3 of the shelf life) - 8°C (2/3 of the shelf life)) during 15 days. The effect of organic acids was also investigated using a lactic acid (1.8% w/w) treatment. At each day of the trials, classical microbiological (total flora) and 16S rDNA metagenomic analysis were carried out on all these samples. For the metagenomic analysis, a sequencing library was generated, targeting the V1-V3 region of the 16S rDNA. The two major bacterial populations were thus identified (Psychrobacter sp and Brochotrix thermosphacta) and predictive microbiology models used to assess the growth parameters. Cardinal parameters for temperature were collected on the two main bacterial species. The model was validated using the data obtained at a dynamic temperature profile. The results of the simulations for Psychrobacter sp and Brochotrix thermosphacta show a good compliance between predicted and observed data. Compared to culture based methods on selective media and previous independent culture techniques, metagenomic analysis combined with predictive microbiology gives more valuable information, and could be considered as a technological breakthrough to control the quality or for accurately determining shelf life. [less ▲]

Detailed reference viewed: 41 (1 ULg)
Full Text
Peer Reviewed
See detailPredictive Modelling Of Temperature And Water Activity (Solutes) On The In Vitro Radial Growth Of Botrytis Cinerea Pers
Lahlali, R.; Serrhini, Mn.; Friel, D. et al

in International Journal of Food Microbiology (2007), 114(1), 1-9

Detailed reference viewed: 28 (0 ULg)