References of "Scientific congresses and symposiums"
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See detailChatter maps for process design of powertrain components
Masset, Luc ULg; Debongnie, Jean-François ULg; Belluco, Walter

in Moisan, Alphonse; Poulachon, Gérard (Eds.) Proceedings of the 7th CIRP International Workshop on Modeling of Machining Operations (2004, May)

During rough machining operations of powertrain components, chatter vibrations may occur on the edges of flexible structures. This paper presents a numerical method, based on the finite element method and ... [more ▼]

During rough machining operations of powertrain components, chatter vibrations may occur on the edges of flexible structures. This paper presents a numerical method, based on the finite element method and Tlusty's theory, which gives a chatter map of the machined surface. Each map point represents the greatest depth of cut leading to unconditionally stable cut. Each value depends on the structural damping, the cutting stiffness and the local static stiffness, which is computed using conventional linear elastic FEA. Chatter maps offer a convenient and effective decision support system for robust process design. As a case study, the rough milling operation of a crankcase deck face with a two-stage cutter is presented. [less ▲]

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See detailDoes insuline resistance in acromegaly differ from that in diabetes ?
Beckers, Albert ULg

in Growth and Beyond Workshop Summary : 16-17 May 2004 (2004, May)

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See detailIncrease of MMP-2 and MMP-9 activity in bronchoalveolar lavage fluid of Ascaris suum sensitized cats and correlation with inflammatory and morphological variables
Kirshvink, N.; Delvaux, François ULg; Vincke, G. et al

in International Conference of the American Thoracic Society - Orlando - USA - Mai 2004 (2004, May)

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See detailEvaluation of prevalence of osteoporosis and osteopenia in men presenting at multiple risk detection campaign
Hanssens, L. C.; De Ceulaer, F.; Tancredi, Annalisa ULg et al

in Osteoporosis International (2004, May), 15(Suppl.1), 54

Detailed reference viewed: 16 (1 ULg)
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See detailEvaluation of the pulmonary inflammation and the bronchial hyperresponsiveness in healthy mice induced by inhaled cyclodextrins
Guéders, Maud ULg; Bertholet, Pascal; Barillaro, Valery et al

Conference (2004, May)

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See detailPatients at high risk of hip fracture benefit from treatment with strontium ranelate
Rizzoli, René; Reginster, Jean-Yves ULg; Diaz-Curiel, M. et al

in Osteoporosis International (2004, May), 15(Suppl.1), 18

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See detailLa copie de la "Cène" de Léonard de Vinci conservée à l'abbaye de Tongerlo
Fagnart, Laure ULg

Conference (2004, April 30)

Detailed reference viewed: 8 (3 ULg)
See detailEntre texte et image : le cas de l'Egypte ancienne
Winand, Jean ULg

Conference (2004, April 29)

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See detailGreenland ice sheet melt: intercomparison between SSM/I and a regional climate model
Fettweis, Xavier ULg

Conference (2004, April 27)

The daily melt extent on the Greenland ice sheet can easily be retrieved from satellite observations and therefore is a very useful index to study the surface mass balance (SMB) evolution of the last ... [more ▼]

The daily melt extent on the Greenland ice sheet can easily be retrieved from satellite observations and therefore is a very useful index to study the surface mass balance (SMB) evolution of the last years. It is also particularly helpful for the validation of a model because there is little in-situ observations on the Greenland ice sheet. The remote sensing melt-detection algorithms use the changes in microwave brightness temperatures during snowmelt. The most used one on Greenland is the cross-polarized gradient ratio (XPGR) method from Abdalati and Steffen (1997)*. It was found from a comparison with simulations made by the regional climate model MAR (Modèle Atmosphérique Régional) that the rainfall on the ice sheet in summer perturbs the melt signal detected by XPGR via the 37-Ghz vertical channel. An improved XPGR algorithm was developed. We present here our motivation to modify the XPGR. An intercomparaison between the SSM/I derived observations and the MAR is performed. The aim is to validate our model, in order to study the SMB for future climate. The simulated extent and time evolution of the wet snow zone compares better with satellite derived data when the modified XPGR method is used. [less ▲]

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See detailThe main characteristics of Saturn's aurora
Grodent, Denis ULg; Gérard, Jean-Claude ULg; Saglam, A. et al

Conference (2004, April 25)

Detailed reference viewed: 4 (1 ULg)
See detailQuantification of lipid bilayer viscosity and fuidity effect induced by propofol.
Bahri, Mohamed Ali ULg; Heyne, Belinda; Hans, Pol ULg et al

Conference (2004, April 23)

Detailed reference viewed: 37 (6 ULg)
See detailL’isocinétisme, une arme de choix
Croisier, Jean-Louis ULg

in Actes du Congrès International de Médecine du Sport (2004, April 23)

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See detailEtat social actif in action: generalists and specialists of employability
Orianne, Jean-François ULg; Moulaert, Thibauld

Conference (2004, April 17)

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See detailA tavola con la natura morta. Quando non resta che consumare il sacro
Dondero, Maria Giulia ULg

in Espressione/Contenuto : Rivista dell’Associazione Italiana di Studi Semiotici (2004, April 11)

Cet article étudie la relation intertextuelle et intersémiotique entre le genre de la nature morte entendue comme Vanitas et Memento mori, la tradition picturale de l’« Et in Arcadia Ego » et quelques ... [more ▼]

Cet article étudie la relation intertextuelle et intersémiotique entre le genre de la nature morte entendue comme Vanitas et Memento mori, la tradition picturale de l’« Et in Arcadia Ego » et quelques photos contemporaines. [less ▲]

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See detailRoles and competencies of the e-tutor
Denis, Brigitte ULg; Watland, Philip; Pirotte, Sébastien et al

in Banks, S.; Goodyear, P.; Hogdson, V. (Eds.) et al Networked learning 2004 : a research based conference on networked learning and lifelong learning : proceedings of the fourth international conference, Lancaster (2004, April 07)

This paper considers the roles and competencies of the e-tutor. A literature review shows that different roles are assigned to the online tutors. Definitions of these roles are presented and discussed ... [more ▼]

This paper considers the roles and competencies of the e-tutor. A literature review shows that different roles are assigned to the online tutors. Definitions of these roles are presented and discussed. Afterwards, we present eleven roles we consider important to manage the interactions between learners and tutors in an e-learning environment and the competencies needed to support these tutor’s roles. We conclude that to improve the quality of e-learning the tutor’s interventions have to be adapted to a specific context and we propose to train the e-tutors for these roles. [less ▲]

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See detailDevelopment of optical ground verification method for mu m to sub-mm reflectors
Stockman, Yvan ULg; Thizy, Cédric ULg; Lemaire, Philippe ULg et al

in Warmbein, B. (Ed.) Proceedings of the 5th International Conference on Space Optics (ICSO) (2004, April 02)

Large reflectors and antennas for the IR to mm wavelength range are being planned for many Earth observation and astronomical space missions and for commercial communication satellites as well. The ... [more ▼]

Large reflectors and antennas for the IR to mm wavelength range are being planned for many Earth observation and astronomical space missions and for commercial communication satellites as well. The challenging tasks of on-ground testing are to achieve the required accuracy in the measurement of the reflector shapes and antenna structures and to verify their performance under simulated space conditions (vacuum, low temperatures). A small number of infrared interferometers have been commercially developed over the last 10 years but their applications have also been limited due to poor dynamic range and the restricted spatial resolution of their detectors. It has therefore been considered essential, from the viewpoint of supporting future ESA exploration missions, to develop and realise suitable verification tools based on infrared interferometry and other optical techniques for testing large reflector structures, telescope configurations and their performances under simulated space conditions. Two methods and techniques are developed at CSL. The first one is an IR-phase shifting interferometer with high spatial resolution. This interferometer shall be used specifically for the verification of high precision IR, FIR and sub-mm reflector surfaces and telescopes under both ambient and thermal vacuum conditions. The second one presented hereafter is a holographic method for relative shape measurement. The holographic solution proposed makes use of a home built vacuum compatible holographic camera that allows displacement measurements from typically 20 nanometres to 25 microns in one shot. An iterative process allows the measurement of a total of up to several mm of deformation. Uniquely the system is designed to measure both specular and diffuse surfaces [less ▲]

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See detailDIC dynamics in the Bay of Palma (NW Mediterranean)
Borges, Alberto ULg; Gazeau, F.; Gattuso, J. P. et al

Poster (2004, April)

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See detailA nested-grid model with data assimilation in the Gulf of Lions
Vandenbulcke, Luc ULg; Barth, Alexander ULg; Alvera Azcarate, Aïda ULg et al

Conference (2004, April)

When a model combines the use of nested grids and data assimilation, a preliminary, simple, 1D test case showed the interest of combining the different state vectors coming from the different grids, into ... [more ▼]

When a model combines the use of nested grids and data assimilation, a preliminary, simple, 1D test case showed the interest of combining the different state vectors coming from the different grids, into one single vector, and using global error matrices covering all the grids at once. In this case, the assimilation procedure provides errorspace feedback from the fine grid to the coarser grid, which proves to be even more important than the statevector feedback. For data located in the fine grid, assimilation of the same data in the coarse grids is not necessary anymore, as both model and errorspace feedback is performed during assimilation. Large data transfers from local to basin-scale models can be avoided. The GHER hydrodynamic model (for a full description, see e.g. [1]) is applied to a three times nested model covering (a) the Mediterrannean Sea at 1/4 degree, (b) the Liguro-Provencal Bassin at 1/20 degree, and (c) the Gulf of Lions at 1/100 degree. The simulation starts on Januari 1st, 1998, using ECMWF atmospheric forcings and MODB4/MEDAR climatic data. As the model allows mode splitting, the simulation uses 2D timesteps of 3 seconds, and 3D timesteps of 3 minutes, on each grid. A twin experiment is performed. The perturbed initial condition is a delayed model state of the reference run. An initial reduced-rank model errorspace is constructed from 20 EOFs, themselves built from the reference run, over all three grids at the same time. Surface temperature and salinity from the reference run are assimilated in the model every 24 hours, using reduced-rank optimal interpolation (see [2]). Different simulations are implemented, using different ways to combine grid nesting and data assimilation: with or without state vector feedback, with data assimilation only in the local grid, or in the coarser grids, or both, and with or without errorspace feedback (i.e. with 3 separated statevectors or with one global statevector). The comparison of those experiments comfirms that using one global statevector reduces the error in the coarser grids much faster. The effect of data assimilation, and the performances of the different methods, can be examined by calculating RMS errors between the perturbed runs and the reference run. They can also be observed by following the model state trajectory in the EOFspace (for example, using the first three EOFs). In the context of the twin experiment described above, the first assimilation cycle clearly brings the model back in time. This is consistent with the choice of the perturbed initial conditions, being a delayed state of the reference run. The following assimilation cycles have little effect, as the trajectory is already almost brought back on the reference trajectory. If other parameters are modified too (e.g. the atmospheric fluxes), each assimilation cycle has an important effect on the modelstate trajectory. A new experiment performs assimilation in the Gulf of Lions in the spring of 1998 using real observations. Different variables can be assimilated, using data collected during the FETCH campaign: NOAA/AVHRR SST, temperature and salinity from Atalante CTDs, or altimetric data from the ERS2 or TOPEX satellites. [less ▲]

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See detailDIC dynamics in a tropical estuary (Kiddogoweni, Kenya)
Borges, Alberto ULg; Frankignoulle, M.; Delille, Bruno ULg et al

Poster (2004, April)

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See detailPreoperative evaluation in the developed countries
Brichant, Jean-François ULg

Conference (2004, April)

Detailed reference viewed: 3 (0 ULg)
See detailA reduced order data assimilation scheme coupled with a two-way nested model. Application to the Ligurian Sea
Barth, Alexander ULg; Alvera Azcarate, Aïda ULg; Beckers, Jean-Marie ULg et al

Conference (2004, April)

A system of nested models is coupled with a data assimilation module. The system is composed by a low resolution model (1/4 ) covering the whole Mediterranean Sea, an intermediate resolution model (1/20 ... [more ▼]

A system of nested models is coupled with a data assimilation module. The system is composed by a low resolution model (1/4 ) covering the whole Mediterranean Sea, an intermediate resolution model (1/20 ) of the Liguro-Provençal basin and a high resolution model (1/60 ) simulating the fine mesoscale structures in the Ligurian Sea. Boundary conditions and the averaged fields (feedback) are exchanged between two successive nesting levels. A reduced order, optimal interpolation data assimilation scheme was implemented. The state vector is composed by temperature, salinity and sea surface elevation. Novel in the present approach is that these variables from the three nested model grids are assembled to one multigrid state vector. This implementation allows to take into account the correlation of the variables across the nested model grids in order to avoid for example artificial gradients after an assimilation cycle. The eigenvectors of the covariance matrix are constructed by an EOF analysis of the free model run. Cross-grid correlations especially in the overlapping domains are thus consistently represented. Horizontal correlations over long distances are suppressed by multiplying each error mode with a set of radial Gaussian functions. This procedure increases considerably the rank of the covariance matrix but ensures the local impact of each observation. Sea surface temperature (SST, from the DLR EOWEB), sea surface height (SSH, from the CLS) and CTD profiles (SIRENA cruise from SACLANT Center and cruises from the MEDAR/Medatlas database) are assimilated into the model. In overlapping model grids the measurements are related to the highest resolution grid. Since the SSH has a resolution of 1/8 , the surface elevation of the Ligurian Sea and the Liguro-Provençal model are filtered in order to be coherent with the space scales present in the observations. Starting from the 1st January 1998 the low and intermediate resolution models are spun up for 18 months. The initial conditions for the Ligurian Sea are interpolated from the intermediate resolution model. The three models are then integrated until August 1999. During this period SST, SSH and the CTD profiles are assimilated. The results are compared with a free model run. In particular the model forecast just before the assimilation step are compared with the observations. The model forecast and the measurements are then independent and the difference is a measure of the model forecast skill and the impact of the previous assimilation cycles. [less ▲]

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See detailForecast verification in the Ligurian Sea. Multiresolution analysis and study of the thermocline
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Rixen, M. et al

Conference (2004, April)

The results of the GHER 3D model are analysed, in order to establish the benefits of a Sea Surface Temperature (SST) assimilation experiment. The influence of the assimilation into the results of the ... [more ▼]

The results of the GHER 3D model are analysed, in order to establish the benefits of a Sea Surface Temperature (SST) assimilation experiment. The influence of the assimilation into the results of the model is examined first in the studied domain, the Ligurian Sea. Then, the benefit of the assimilation outside this domain (in the nearby zones at the surface, and in the Ligurian Sea at depth) is also studied. Finally, the effect of the SST assimilation on the other variables is examined. The procedure for the skill assessment of the model is as follows. First, the classical verification tools are applied: Root Mean Square Error (RMSE), Anomaly Correlation Coefficient (ACC), and Mean Square Error Skill Score (MSESS). Climatology and a free run of the model are used as reference systems. After this, a multiresolution analysis is carried out, to decompose the model results into different spatial scales. At each scale, the error measures mentioned above are applied. This allows to establish which scales are mainly contributing to the error. For this multiresolution analysis, a Discrete Wavelet Transform is used. The study of the assimilation benefits at depth is made by comparison with CTDs. The aim is to study the position and strength of the thermocline, as this zone presents high variability and it has an important impact into the system. A good representation of the thermocline is thus interesting. [less ▲]

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See detailForecast assessment in the mediterranean sea : A structure oriented approach
Ben Bouallegue, Z.; Alvera Azcarate, Aïda ULg; Vandenbulcke, Luc ULg et al

Conference (2004, April)

The MFSTEP1 project is an international scientific collaboration program which aims to create an operational forecasting system for the Mediterranean sea. The simulations provided at the basin scale are ... [more ▼]

The MFSTEP1 project is an international scientific collaboration program which aims to create an operational forecasting system for the Mediterranean sea. The simulations provided at the basin scale are 10 days forecasting fields in a 3-D ocean. The hydrodynamic model primitive equations are combined with the data assimilation scheme SOFA2. The data collection is done in a near real time process and the set of XBT and SLA observations are used in one week assimilation cycle. The forecast assessment is traditionally realised using classical statistic tools like RMSE or the bias and the assimilation benefit is estimated by skill scores using as reference the free model, persistence or also climatology. The process is essentially based on the comparison of two fields at a fixed time, one corresponding to the simulations and the other one to the observations. The interest of such statistical methods comes in the quick and sensitive appreciation they provide about the quality, accuracy and consistency of the simulation. However this kind of assessment procedure brings in it self a conceptual contradiction: performances of a dynamical process are measured using a snap shot view of the ocean state. A system evolution assessment procedure is carried out within the framework of the MFSTEP hindcast. The hindcast system is intrinsically analysed (without independent informations) comparing the background forecast evolution with the abrupt variation which occurs at the observations assimilation time steps. The system evolution between two consecutive days is analysed using a decomposition method. The temperature and salinity fields evolution in a sub-region of theWestern Mediterranean basin is seen in a structural point of view and decomposed in three elements : a global spatial(2D) displacement which conserves the internal features, a global intensity variation which expresses the system energy changes, and an internal pattern changes ensemble. The index of evolution used is a mean squared difference between the two consecutive simulations. The displacement contribution is estimated after the determination of the shift (field translation) which minimises the local mean squared difference between the translated field and the next simulation. The intensity variation contribution is calculated as the difference of the squared mean fields. The remaining difference after manipulations is considered as the internal pattern changes contribution to the system evolution. [less ▲]

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See detailJets instabilities producing the slot-tone
Billon, Alexis ULg; Valeau, Vincent; Sakout, Anas

Conference (2004, April)

The nature of the instability governing the self-sustained tones produced by a low Mach number free plane jet impinging on a slotted plate, known as slot-tone, is identified experimentally. The ... [more ▼]

The nature of the instability governing the self-sustained tones produced by a low Mach number free plane jet impinging on a slotted plate, known as slot-tone, is identified experimentally. The experimental apparatus permits to control the Reynolds number and the distance from the jet outlet to the plate. For a Reynolds number, the shear-layer natural frequency and the jet column mode frequency of the free jet without the obstacle are estimated and compared to the minimal and maximal frequencies of the tones (for any position of the plate). The frequency of both instabilities defines the frequency domain of the self sustained tones. The lowest frequencies of the tones, obtained when the plate is placed downstream the end of the potential core, are the result of the amplification of the column mode frequency. On the other hand, the maximal frequency of the tones, obtained when the plate is situated near the jet outlet, is close to the natural shear-layer frequency. Moreover, when the tones frequency is higher than the natural shear-layer frequency, the sound pressure level produced is very inferior to the maximal sound pressure level measured at the same Reynolds number. This confirms the prominent role of the shear-layer instability in the self-sustained tones process for the highest frequencies. Tones with a frequency lower than the jet column mode frequency are rarely observed. [less ▲]

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See detailSimulation of the acoustics of coupled rooms by numerical resolution of a diffusion equation
Valeau, Vincent; Picaut, Judicaël; Sakout, Anas et al

Conference (2004, April)

Over the last few years, some studies showed that the acoustic energy density in closed or semi-closed spaces may be the solution of a diffusion equation. This theory allows non-uniform repartition of ... [more ▼]

Over the last few years, some studies showed that the acoustic energy density in closed or semi-closed spaces may be the solution of a diffusion equation. This theory allows non-uniform repartition of energy, and is especially relevant in room acoustics for long rooms or complex spaces such as networks of rooms. In this work, the three-dimensional diffusion equation is solved directly by using a finite-element solver. This approach is used to simulate the acoustics of coupled rooms in terms of spatial variations of intensity levels and sound decay. The obtained results match satisfactorily with a model based on the classical statistical theory of room acoustics, but it allows to perform a finer spatial description of the acoustics of coupled rooms. [less ▲]

Detailed reference viewed: 47 (0 ULg)
See detailCarbon dioxide dynamics in Antarctic pack ice and transfer at the ice-sea and air-ice interfaces
Delille, Bruno ULg; Trevena, A.; Lannuzel, D. et al

Conference (2004, April)

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See detail'Soil microbial diversity and forest ecosystem functioning
Carnol, Monique ULg

Conference (2004, April)

The term ‘biodiversity’ has been defined as ‘The variety of life in all its forms, levels and combinations’, with the concept including several scales (ecosystem diversity, species diversity, and genetic ... [more ▼]

The term ‘biodiversity’ has been defined as ‘The variety of life in all its forms, levels and combinations’, with the concept including several scales (ecosystem diversity, species diversity, and genetic diversity) and processes related to ecosystem functioning (role in food webs, primary productivity, biogeochemical cycling). Ecosystem diversity comprises plant, animal and microbial diversity. Whereas much research focuses on plant and animal diversity, complexity of interactions and methodological difficulties have so far limited research on microbial diversity. However, within the soils of forest ecosystems, microorganisms are responsible for key functions such as organic matter decomposition and mineralisation, in particular within the C and N cycles. These processes are closely linked to nutrient availability and therefore play an important role in stand productivity, tree health and ecosystem functioning. Within the attempts to use soil microbial communities as indicators of soil health, microorganisms and their functions have been classified according to their sensitivity to perturbations. Processes of mineralization, linked to soil productivity, were ranked with the highest priority. Because of the small number of organisms involved and their key role in nutrient cycling, nitrifying bacteria and the nitrification process were identified as very sensitive to environmental perturbation. In this paper, I present an overview of ongoing studies investigating the link between the nitrification process and the diversity of ammonia-oxidisers, bacteria responsible for the first, rate-limiting step of the nitrification process. Ammonia-oxidiser community structure was investigated using a PCR-based approach targeting the 16S rRNA gene of beta-subgroup ammonia oxidisers, followed by DGGE (Denaturing Gradient Gel Electrophoresis) and sequence analysis. The analysis of community structure was combined with more traditional measurements of nitrate production and soil characteristics. Investigations included several Belgian forest ecosystems and the effects of environmental factors, such as liming and the effects of a 4-year exposure to elevated CO2. [less ▲]

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See detailRiver contract in the Sourou valley (Burkina Faso)
Rosillon, Françis ULg

in Muuka, Gerry Nkombo (Ed.) 2004 IAABD Proceedings (2004, April)

Inspired from the experience of river contract in Wallonia (Belgium) since 1990, this paper is describing the implementation of the first river contract in a West-African country, Burkina Faso. This ... [more ▼]

Inspired from the experience of river contract in Wallonia (Belgium) since 1990, this paper is describing the implementation of the first river contract in a West-African country, Burkina Faso. This application isn't limited to a simple transposition of the Walloon model. The Burkina context calls to adaptation to the local environmental and socio-economical realities with an adequate partnership management. The importance of the mobilissation around this project of institutional partners, as well as local collectivities this new tool of water participative management. But will the latter be equal to the task ? A first assessment has been drawn up one year after the launching. [less ▲]

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See detailOn Dictatorship, Economic Development and Stability
Artige, Lionel ULg

Conference (2004, April)

Detailed reference viewed: 23 (2 ULg)
See detailSurgical debulking of GH secreting pituitary adenomas improves GH control of acromegaly by somatostatin analogs
Beckers, Albert ULg; Petrossians, Patrick ULg; Borges Martins, L. et al

in ENEA congress : Napoli, April 2004 (2004, April)

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See detailPartial encryption of images for real-time applications
Van Droogenbroeck, Marc ULg

in Fourth IEEE Signal Processing Symposium (2004, April)

Multimedia systems mostly base security on a restricted access to services. In the context of real-time imaging applications, this model suffers several drawbacks. Applications become vulnerable to ... [more ▼]

Multimedia systems mostly base security on a restricted access to services. In the context of real-time imaging applications, this model suffers several drawbacks. Applications become vulnerable to password attacks and once exposed attackers have access to all the data. An alternative consists of the systematic encryption of all data. When dealing with images, this approach is inconvenient because the data needs to be processed in its entirety before users can gain any insight. As well, the decryption task requires large amounts of processing power. This presentation shows how partial encryption can match applications requirements without the overhead of full encryption. The paper rst analyzes several schemes mixing encryption and image encoding. Then we focus on a technique that implements partial encryption of images based on JPEG. The technique is built to meet two major requirements: (1) preserve the overall bitrate, and (2) remain compliant with the JPEG file format. Finally we introduce and elaborate on a new scheme that combines flexibility, multiple encryption, spatial selectivity, self sufficiency, and format compliance. We show how it could fit the needs of real-time applications. [less ▲]

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See detailStability and Limit Cycle Oscillation Amplitude Prediction for Simple Nonlinear Aeroelastic Systems
Dimitriadis, Grigorios ULg; Vio, Gareth Arthur; Cooper, Jonathan Edward

in Proceedings of the 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference (2004, April)

The prediction of the bifurcation and post-bifurcation behaviour of nonlinear aeroelastic systems is becoming a major area of research in the aeroelastic community due to the need for improved transonic ... [more ▼]

The prediction of the bifurcation and post-bifurcation behaviour of nonlinear aeroelastic systems is becoming a major area of research in the aeroelastic community due to the need for improved transonic aeroelastic prediction, the use of non-linear control systems, and new construction techniques that reduce the amount of inherent damping. In this paper, a novel application of the Centre Manifold Theorem is used to accurately predict bifurcation conditions and Limit Cycle Oscillation amplitudes for simple aeroelastic systems with various types of nonlinearity. A simple aeroelastic system with hardening cubic stiffness nonlinearity is considered and is demonstrated to display a wide variety of bifurcation phenomena. These make it dif cult for some of the standard existing methods, such as Normal Form, Cell Mapping and Tangential Linearisation, to quantify the Limit Cycle Oscillation amplitudes through the entire speed range of the system. Then, the proposed approach is introduced and applied to the same system. It is shown that it can accurately predict the limit cycle amplitudes of the system undergoing all types of bifurcation. Finally, the new technique is applied to the same system but with softening cubic stiffness nonlinearity. It is shown that the method can accurately predict both the static and dynamic divergence boundaries and that it can be used to draw a worst-case stability boundary, inside which the solution is always stable. [less ▲]

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See detailMale hypogonadism caused by isolated LH deficiency : From pathology to gene, from gene to physiology
Valdes Socin, Hernan Gonzalo ULg; Salvi, R.; Pralong, F. et al

in ENEA congress : Napoli, April 2004 (2004, April)

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See detailHormonal and biochemical normalization and tumor shrinkage induced by anti-parathyroid hormone immunotherapy in a patient with metastatic parathyroid carcinoma
Betea, Daniela ULg; Bradwell, A. R.; Harvey, T. C. et al

in ENEA congress : Napoli, April 2004 (2004, April)

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See detailEvolution de l’herpèsvirus bovin 4 au cours des 1,5 derniers millions d’années
Dewals, Benjamin G ULg; Markine-Goriaynoff, Nicolas; Gaillard, Claude et al

Conference (2004, April)

L’herpèsvirus bovin 4 (BoHV-4) est un gammaherpèsvirus appartenant au genre Rhadinovirus. Récemment, une étude phylogénique a démontré que le gène Bo17 du BoHV-4 codant pour un homologue fonctionnel de la ... [more ▼]

L’herpèsvirus bovin 4 (BoHV-4) est un gammaherpèsvirus appartenant au genre Rhadinovirus. Récemment, une étude phylogénique a démontré que le gène Bo17 du BoHV-4 codant pour un homologue fonctionnel de la C2GnT-M cellulaire a été acquis d’un ancêtre direct ou indirect du buffle africain (Syncerus caffer) il y a quelques 1,5 millions d’années (Markine-Goriaynoff, N. et al. 2003. The core 2 beta-1,6-N-acetylglucosaminyltransferase-mucin encoded by bovine herpesvirus 4 was acquired from an ancestor of the African buffalo. J Virol 77:1784-92). Dans la présente étude, deux objectifs ont été poursuivis. Premièrement, dans le but de préciser l’origine du gène Bo17 du BoHV-4, le gène de la C2GnT-M de diverses sous-espèces de buffles a été séquencé. Les sous-espèces sélectionnées appartiennent aux espèces Syncerus caffer (pour les sous-espèces caffer, aequinoctialis et nanus) et Bubalus bubalis (pour les sous-espèces River, Swamp et Murrah). L’analyse phylogénique des séquences obtenues démontre que le BoHV-4 a acquis son gène Bo17 à partir d’un ancêtre direct de la sous-espèce Syncerus caffer caffer, soit bien après la séparation des Syncerus et des Bubalus. Le second but de cette étude était de déterminer si les souches de BoHV-4 isolées en Afrique à partir de buffle africain forment un groupe phylogénétiquement distinct au sein de l’espèce BoHV-4. Dans ce but, neuf souches représentatives de l’espèce BoHV-4 (dont trois isolées de buffle africain) ont été sequencées au niveau de 5 régions réparties sur l'entièreté du génome viral. L’analyse phylogénique de ces sequences démontre l’existence d’événements de recombinaisons inter-souches survenus récemment au cours de l’évolution. En conclusion, cette étude phylogénique a permis d’étabir que (i) le gène Bo17 du BoHV-4 a été acquis d’un ancêtre direct de la sous-espèce Syncerus caffer caffer de buffle africain, et (ii) que le génome du BoHV-4 a subi par la suite des phénomènes de recombinaisons inter-souches. [less ▲]

Detailed reference viewed: 39 (13 ULg)
See detailApproaching the true prevalence of pituitary tumors
Beckers, Albert ULg; Adam, C.; Ciccarelli, A. et al

in ENEA congress : Napoli, April 2004 (2004, April)

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See detailInfluence of Parenteral Multivitamins Concentration on Neonatal Lung
Senterre, Thibault ULg

in Pediatric Research (2004, April), 55(4), 445

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See detailEffect of various level of imbalance between energy ans nitrogen supplies on nitrogen metabolism in growing double-muscled Belgian Blue bulls.
Valkeners, Damien; Beckers, Yves ULg; Thewis, André ULg

in Proceeding of the British Society of Animal Science - Annual meeting (2004, April)

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See detailInvestigations on the development of the health status of harbour seals in the year of the PDV seal die-off in 2002
Siebert, Ursula; Fonfara, Sonja; Hasselmeier, Ilka et al

Poster (2004, March 31)

More than 21,500 harbour seals were killed by Phocine Distempter Virus in the North Sea and adjacent waters in 2002. Of those more than 3,340 seals were found dead on the coast of Schleswig-Holstein ... [more ▼]

More than 21,500 harbour seals were killed by Phocine Distempter Virus in the North Sea and adjacent waters in 2002. Of those more than 3,340 seals were found dead on the coast of Schleswig-Holstein. After the second seal die-off had ceased, seals were captured alive for a health check and also stranded seals were examined for their health status. Blood status and chemistry tests were performed, microbiological, parasitological, histological, serological and cytological investigations were conducted. During the first catch after the seal die-off animals seemed to be in clinically good condition although hematological disturbances (leucocytosis as well as leucopenia) were detected. Bacteriologically, Bordetella bronchisptica was isolated, a bacterium which was exclusively cultured during the seal die-off. At later catches hematological values normalized and also the normal bacterial flora was cultured from vagina and anus. The serological investigations for morbillivirus-specific antibodies revealed positive titers in 100% of the seals. Morphologically, there was no evidence for a continuing morbillivirus infection by both, histology and immunocytochemistry. The pathomorphological changes were similar to those before the epizootic including the predominance of parasitic and bacterial bronchopneumonia, emaciation and dermatitis. Contrary to the first seal die-off in 1988/89 an increased number of large skin wounds on the ventral side and infections of the umbilicus were not seen. This may indicate that the seal population in Schleswig-Holstein was generally in better health condition at the second seal die-off compared to the first one. The continued investigations will allow a further assessment of the development of the seal population in the Wadden Sea. [less ▲]

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See detailNoyaux de dattes: étude de la composition physico-chimique et des profils caractéristiques de la fraction lipidique
Besbes, S.; Blecker, Christophe ULg; Deroanne, C. et al

Conference (2004, March 21)

Detailed reference viewed: 344 (1 ULg)
See detaile-nose for malodour monitoring
Romain, Anne-Claude ULg

Poster (2004, March 21)

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See detailContribution à l'extraction et à la caractérisation des fibres de la pulpe de dattes
Elleuch, M.; Besbes, S.; Blecker, Christophe ULg et al

Conference (2004, March 21)

Detailed reference viewed: 13 (1 ULg)
See detailEtre scribe ou la transmission du savoir
Winand, Jean ULg

Conference (2004, March 20)

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Peer Reviewed
See detailLe fonctionnement des assemblées générales et des conseils d’administration
Kohl, Benoît ULg

Conference (2004, March 19)

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Peer Reviewed
See detailLe travail de Caroline Leaf. Imagination tactile et cinéma d’animation
Tomasovic, Dick ULg

Conference (2004, March 17)

Detailed reference viewed: 6 (1 ULg)
See detailAntihypertenseur et AVC - de la prévention au traitement
Krzesinski, Jean-Marie ULg

Conference (2004, March 15)

Detailed reference viewed: 32 (8 ULg)
See detailL’actualité imaginaire de Sartre et Foucault
Cormann, Grégory ULg; Giovannangeli, Daniel ULg

Conference (2004, March 13)

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See detailLes mammites en élevage laitier. Outils et stratégies de diagnostic.
Hanzen, Christian ULg

Conference (2004, March 12)

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See detailETUDE PAR IMAGERIE NUMERIQUE ET GRANULOMETRIE LASER DE L'INFLUENCE DE HUIT ADJUVANTS SUR LA FORMATION DU JET DE PULVERISATION POUR TROIS TYPES DE BUSES.
Stainier, Charles; Lebeau, Frédéric ULg; Straet, S. et al

Conference (2004, March 11)

The liquid sheet characteristics as a function of the adjuvant were measured using digital images. The droplet size distribution was measured using a Malvern particle size analyser. It appears that the ... [more ▼]

The liquid sheet characteristics as a function of the adjuvant were measured using digital images. The droplet size distribution was measured using a Malvern particle size analyser. It appears that the dynamical surface tension plays a critical role in the spray formation. Spray formulation containing Li-700, Silwet L-77, Flofix and Actirob are characterised by a lower dynamical surface tension than those containing Tensiofix D03, Trend 90, Frigate and Break-thru S240. For the three agricultural spray nozzles tested and in comparaison with pure water, the first group shortened the length of the liquid sheet before a perforation break-up mode when the second group lengthened it slightly before a wave disintegration break-up mode. The lengthening of the liquid sheet, is followed by a diminution of the VMD. [less ▲]

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See detailHypertension artérielle : nouvelles directives de prise en charge.
Krzesinski, Jean-Marie ULg

Conference (2004, March 11)

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See detailOn the coupling of primary production and calcification at the continental margin
Harlay, Jérôme ULg; Chou, Lei; Roevros, Nathalie et al

Poster (2004, March 05)

Until now, little attention has been paid to the processes controlling the production, dissolution and fate of biogenic calcium carbonate in the oceans. It is however well known that net deposition rates ... [more ▼]

Until now, little attention has been paid to the processes controlling the production, dissolution and fate of biogenic calcium carbonate in the oceans. It is however well known that net deposition rates of inorganic carbon to the sediments are comparable to those of organic matter. There remains still large uncertainties concerning the production and redissolution of biogenic carbonate in the marine system and thus about the role of the carbonate pump in response to anthropogenic CO2 perturbations. The understanding of these processes is also a prerequisite to predict the response of marine organisms to global environmental changes. In the framework of the Belgian global change programme, we have developed a project devoted to the study of the inorganic carbon cycle in the Bay of Biscay where coccolithophorid blooms occur frequently. The study focuses on processes associated with the oceanic production and dissolution of calcium carbonate, by combining field investigations, laboratory experiments and modelling efforts. Remote sensing demonstrates a close relationship between vertical mixing along the continental margin and the development of the phytoplankton bloom. We will present here, results of 14C incorporation experiments used to evaluate the rate of production of organic and inorganic particulate carbon, obtained during a coccolithophorid spring bloom in the investigated area. A tentative mass balance of the carbon fluxes for this area will be presented, confirming the importance that the calcium carbonate pump may play in the oceanic system. [less ▲]

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See detailCarbon dioxide transfer at the ice-sea and air-ice interfaces: a step towards the end of a long-lived paradigm ?
Delille, Bruno ULg; Trevena, A.; Lannuzel, D. et al

Poster (2004, March 05)

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See detailOptimization of the encapsulation of Thrombin Receptor Agonist Peptide in PLGA microbeads
Stashevskaya, Kira; Grandfils, Christian ULg; Markvicheva, E. et al

Conference (2004, March 04)

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See detailPlace du sartan dans l'hypertension artérielle
Krzesinski, Jean-Marie ULg

Conference (2004, March 04)

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See detailLa césarienne dans l'espèce bovine. Protocole de réalisation.
Hanzen, Christian ULg

Conference (2004, March)

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See detailRegional blood flows of hypoplastic left heart infants ventilated with non conventional PEEPs
Rigo, Vincent ULg; Escoredo, Sandra; Robertson, Murray et al

in Tijdschrift van de Belgische Kinderarts = Journal du Pédiatre Belge (2004, March)

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See detailUtilisation du MEOPA en pédiatrie
ROUSSEAU, Anne-Françoise ULg; LEPAGE, Philippe; TOMAT, Anne-Marie

Poster (2004, March)

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See detailReliable simulation of mechatronic systems using Newmark algorithms
Bruls, Olivier ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

Conference (2004, March)

In the framework of flexible multibody systems simulation, the stability and the accuracy of the time integration process can be guaranteed by a family of implicit integrators derived from the Newmark ... [more ▼]

In the framework of flexible multibody systems simulation, the stability and the accuracy of the time integration process can be guaranteed by a family of implicit integrators derived from the Newmark scheme (Hilber-Hughes-Taylor and Generalized- methods). This paper deals with the extension of those reliable integrators for the simulation of mechatronic systems. In order to account for the strong coupling between the mechanism and the control system, the coupled set of equations contains mechanical and control variables. The generation of those equations, their numerical treatment and their time integration may become unmanageable for realistic control systems. In many cases, it is however sufficient to consider a weak coupling, which means that the action of the control system is treated as an external force disturbing the dynamic equilibrium. The weak coupling assumption is fully justified when a digital controller is present in the control loop. Then, the control actions exhibit discontinuous transitions at each sampling instant. The standard form of the Newmark scheme assumes continuity of the acceleration variables, and is thus not appropriate for this situation. Therefore, we propose an adapted Newmark scheme which achieves an explicit treatment of the acceleration jumps throughout the integration process, so that the proper simulation of the mechatronic system is guaranteed. The paper describes the detailed modifications of the integration algorithm. Illustrative examples are used to point out the critical situations where they prevent from substantial integration errors. [less ▲]

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See detailCharakterisierung des bronchialen “remodellings” in einem Modell von felinem Asthma
Kirschvink, N.; Delvaux, François ULg; Vincke, G. et al

in 45. Kongress der Deutschen Gesellschaft für Pneumologie - Frankfurt - Allemangne - Mars 2004 (2004, March)

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See detailAnaerobic power and isokinetic strength of basketball players
Lehance, Cédric ULg; Croisier, Jean-Louis ULg; Schiltz, Marc et al

in Isokinetics & Exercise Science (2004, March), 12(1), 62-63

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See detailEvaluation de l'expression orale et de l'expression écrite en langues étrangères : présentation et analyse de différents outils
Beckers, Jacqueline ULg; Simons, Germain ULg; Van Hoof, Florence ULg et al

in Actes du 3ème congrès des chercheurs en éducation : (re)trouver le plaisir d'enseigner et d'apprendre. Construire savoirs et compétences (2004, March)

Cette communication présente une réflexion sur le type de tâches à proposer lors de l évaluation certificative, ensuite sur les critères à prendre en compte et enfin sur les indicateurs de réussite. Cette ... [more ▼]

Cette communication présente une réflexion sur le type de tâches à proposer lors de l évaluation certificative, ensuite sur les critères à prendre en compte et enfin sur les indicateurs de réussite. Cette réflexion repose d'une part sur un programme de recherche-action portant sur l optimisation de l expression orale en anglais/langue étrangère [2000-2002], et sur un autre programme de recherche-action portant sur l identification et la déconstruction de stéréotypes liés à la langue et à la culture étrangères (néerlandais et français) [2002-2004], et d'autre part sur les travaux réalisés au sein de la Commission de Pilotage du Système éducatif. [less ▲]

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See detailLa coordination horizontale, un mode de gestion des compétences stratégique pour une justice face à de nouvelles exigences ?
Schoenaers, Frédéric ULg

in Management des compétences et des connaissances : outils stratégiques en GRH (2004, March)

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See detailION BEAM FIGURING OF CVD SILICON CARBIDE MIRRORS
Gailly, Patrick ULg

in Warmbein, B (Ed.) Proceedings of the 5th International Conference on Space Optics (ICSO 2004) (2004, March)

Optical and structural elements made of silicon carbide are increasingly found in space instruments. Chemical vapor deposited silicon carbide (CVD-SiC) is used as a reflective coating on SiC optics in ... [more ▼]

Optical and structural elements made of silicon carbide are increasingly found in space instruments. Chemical vapor deposited silicon carbide (CVD-SiC) is used as a reflective coating on SiC optics in reason of its good behavior under polishing. The advantage of applying ion beam figuring (IBF) to CVD-SiC over other surface figure-improving techniques is discussed herein. The results of an IBF sequence performed at the Centre Spatial de Liège on a 100 mm CVD-SiC mirror are reported. The process allowed to reduce the mirror surface errors from 243 nm to 13 nm rms . Beside the surface figure, roughness is another critical feature to consider in order to preserve the optical quality of CVD-SiC . Thus, experiments focusing on the evolution of roughness were performed in various ion beam etching conditions. The roughness of samples etched at different depths down to 3 m was determined with an optical profilometer. These measurements emphasize the importance of selecting the right combination of gas and beam energy to keep roughness at a low level. Kaufman-type ion sources are generally used to perform IBF but the performance of an end-Hall ion source in figuring CVD-SiC mirrors was also evaluated in this study. In order to do so, ion beam etching profiles obtained with the end-Hall source on CVD-SiC were measured and used as a basis for IBF simulations. [less ▲]

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See detailPrésentation de deux grandes approches didactiques destinées à articuler compétences et savoirs dans le domaine de l'apprentissage des langues étrangères en contexte scolaire
Beckers, Jacqueline ULg; Simons, Germain ULg; Van Hoof, Florence ULg et al

in Actes du 3ème congrès des chercheurs en éducation : (re)trouver le plaisir d'enseigner et d'apprendre. Construire savoirs et compétences (2004, March)

Dans cette communication, nous présenterons deux grandes approches didactiques destinées à articuler compétences et savoirs linguistiques dans le domaine de l enseignement de l anglais et du néerlandais ... [more ▼]

Dans cette communication, nous présenterons deux grandes approches didactiques destinées à articuler compétences et savoirs linguistiques dans le domaine de l enseignement de l anglais et du néerlandais/langues étrangères. Dans les deux cas, le public-cible est constitué d élèves évoluant dans l enseignement secondaire général supérieur. [less ▲]

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See detailDesign of nanoobjects endowed with specific properties
Willet, Nicolas ULg; Qiu, Hongjin; Rieger, Jutta ULg et al

Conference (2004, March)

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See detailEvaluation of plyometric training on functional performances and isokinetic strength
Lehance, Cédric ULg; Croisier, Jean-Louis ULg; Maquet, Didier ULg et al

in Isokinetics & Exercise Science (2004, March), 12(1), 79-80

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See detailImplication of surface charge effects in color removal from effluents by chemical coagulation - the case of CI Reactive Blue 4 dye
Gaydardzhiev, Stoyan ULg; Ay, Peter

in Pratsinis, S. (Ed.) Proceeedings CD of Partec 2004 Inetrnational Congress of Particle Technology (2004, March)

Characterisation of dye flcos during colour removal from synthetic waste water is presented. Surface charge and floc size and shapes are measured and an implications towards the predominant removal ... [more ▼]

Characterisation of dye flcos during colour removal from synthetic waste water is presented. Surface charge and floc size and shapes are measured and an implications towards the predominant removal emchanisms is made. [less ▲]

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See detailPulsed holographic interferometry with photorefractive crystals. Recent advances of the european “PHIFE” project
Georges, Marc ULg; Lemaire, Philippe; Pauliat, Gilles et al

Conference (2004, March)

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See detailParotidite bactérienne du prématuré
Rigo, Vincent ULg; Hansoul, Sandrine; Rausin, Léon et al

in Journal du Pédiatre Belge (2004, March)

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See detailHypertension artérielle et diabète : comment gérer?
Krzesinski, Jean-Marie ULg

Conference (2004, February 19)

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See detailInvalidation du gène Rhcg de la famille rhésus
Biver, Sophie ULg

Conference (2004, February 19)

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See detailSuccès ou réussite ? Formes et normes de la consécration symbolique
Durand, Pascal ULg

Conference (2004, February 19)

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See detailBilan d'une saison très tardive du point des maladies: Résultats des essais fongicides en 2003 sur le site de Lonzée
Vancutsem, Françoise ULg; Moreau, Jean-Marc; Bodson, Bernard ULg

in Fumure et protection phytosanitaire des céréales (2004, February 18)

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See detailLes conseils de fumure azotée
Bodson, Bernard ULg; Destain, Jean-Pierre ULg; Vancutsem, Françoise ULg et al

in Fumure et protection phytosanitaire des céréales (2004, February 18)

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See detailFroments alternatifs et de printemps
Couvreur, Luc; Vancutsem, Françoise ULg; Bodson, Bernard ULg et al

in Fumure et protection phytosanitaire des céréales (2004, February 18)

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See detailFractionnement de la fumure azotée: deux ou trois fractions? fumure au tallage ou pas?
Bodson, Bernard ULg; Vancutsem, Françoise ULg; Destain, Jean-Pierre ULg et al

in Fumure et protection phytosanitaire des céréales (2004, February 18)

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See detailInventory control in a multi-supplier system
Arda, Yasemin ULg; Hennet, Jean-Claude

in IGLS 04, 13th International Working Seminar on Production Economics, Igls/Innsbruck, Austria, 16-20 February 2004 (2004, February 16)

An enterprise network is analyzed from the viewpoint of an end-product manufacturer who receives customer orders and organises his production and supply policy so as to minimize the sum of his average ... [more ▼]

An enterprise network is analyzed from the viewpoint of an end-product manufacturer who receives customer orders and organises his production and supply policy so as to minimize the sum of his average holding cost and average stock-out cost. For each main component to be ordered, the producer has several possible suppliers. The arrivals of customers’ orders are random and delivery times from suppliers are also supposed random. This supply system is represented as a queuing network and the producer uses a base-stock inventory control policy that keeps constant the position inventory level (current inventory level + pending replenishment orders). The decision variables are the reference position inventory level and the percentages of orders sent to the different suppliers. In the queuing network model, the percentages of orders are implemented as Bernoulli branching parameters. A close-form expression of the expected cost criterion is obtained as a complex non-linear function of decision variables. A decomposed approach is proposed for solving the optimization problem in an approximate manner. The quality of the approximate solution is evaluated by comparison to the exact solution, which can be computed numerically in some simple cases, in particular in the two-supplier case. Numerical applications show the important economic advantage for the producer of sending orders to several suppliers rather than to a single one. [less ▲]

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See detailLipolysis inhibition by proteose-peptone : an interfaciale study.
Danthine, Sabine ULg; Blecker, Christophe ULg; Deroanne, Claude

Poster (2004, February 11)

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See detailStudy of synthesis and surface activity of inulin lauric esters.
Ius, E.; Blecker, Christophe ULg; Verardo, G. et al

Poster (2004, February 11)

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See detailSurface properties of two closely related sugar esters : glucose octanoate and octyl glucuronate.
Blecker, Christophe ULg; Deroanne, Claude; Moreau, B. et al

Poster (2004, February 11)

Detailed reference viewed: 13 (2 ULg)