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See detailReconstruction and analysis of QuikSCAT wind measurements with an EOF-based technique
Troupin, Charles ULg; Alvera Azcarate, Aïda ULg; Beckers, Jean-Marie ULg

Poster (2012, April 24)

QuikSCAT wind products are often used to provide numerical model atmospheric forcing. However, due to the configuration of the satellite swaths, gaps are frequently observed in the daily wind maps. We ... [more ▼]

QuikSCAT wind products are often used to provide numerical model atmospheric forcing. However, due to the configuration of the satellite swaths, gaps are frequently observed in the daily wind maps. We present a solution based on truncated EOF decomposition to fill these gaps. [less ▲]

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See detailLa reconstruction congolaise
Kabamba, Bob ULg; Zacharie, Arnaud

Book published by Luc Pire (2009)

Detailed reference viewed: 35 (6 ULg)
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See detailReconstruction de données satellitaires manquantes du lac Tanganyika
Leblanc, Christophe ULg

Master's dissertation (2007)

Ce mémoire présente une technique de reconstruction des données manquantes du lac Tanganyika basée sur une version modifiée de l’algorithme de décomposition en EOFs (Empirical Orthogonal Functions) et qui ... [more ▼]

Ce mémoire présente une technique de reconstruction des données manquantes du lac Tanganyika basée sur une version modifiée de l’algorithme de décomposition en EOFs (Empirical Orthogonal Functions) et qui consiste en l’utilisation d’une généralisation du théorème SVD (Singular Value Decomposition) des matrices aux tenseurs d’ordre trois. Les performances de ces deux algorithmes sont ensuite comparées sur les données satellitaires du lac Tanganyika fournies par Yves Cornet*, le but étant de reconstruire ces données sur toute la surface du lac. *Université de Liège Département de géographie / Unité de Géomatique - Télédétection et photogrammétrie. ycornet@ulg.ac.be [less ▲]

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See detailReconstruction de la papille: Un défi
LAMBERT, France ULg

Conference (2012)

La dentisterie esthétique moderne est principalement basée sur la bonne harmonie gingivodentaire. Le challenge pour restaurer l'esthétique d’un sourire est souvent de recréer cet équilibre entre les ... [more ▼]

La dentisterie esthétique moderne est principalement basée sur la bonne harmonie gingivodentaire. Le challenge pour restaurer l'esthétique d’un sourire est souvent de recréer cet équilibre entre les tissus mous et la réhabilitation prothétique. Au cours de cette session, nous aborderons plus spécifiquement l’aspect des tissus mous, de leur architecture, de leur intégration avec les éléments prothétiques et de leurs volumes, etc.... Un des éléments clef de cette architecture des tissus mous est la présence des papilles inter-dentaires. Les objectifs de cette session se résument en trois volets : Tout d’abord, le point sera fait sur les différentes causes des pertes papillaires. Nous envisagerons aussi comment les éviter ou les limiter à travers des actes chirurgicaux moins invasifs, en respectant davantage la physiologie des tissus parodontaux. La prévention de la perte des papilles passe aussi par le choix des matériaux et par les actes prothétiques. Ces aspects seront également discutés. Ensuite, le second objectif de cet exposé visera, en cas d’absence papillaire, à analyser la situation clinique et d’en définir le pronostique de régénération. Le pronostique est évalué sur base des connaissances actuelles issues de la littérature scientifique, et par le biais d’une bonne analyse esthétique et radiographique de la situation clinique. Dès lors, en fonction d’un pronostic favorable, modéré, ou défavorable, les options de reconstruction papillaire pourront être pondérées. Enfin, la dernière partie de cette conférence sera dédiée aux techniques et méthodes de régénération papillaires. À travers de nombreux cas cliniques, les différentes techniques de régénération des papilles, qu’elles soient chirurgicales, orthodontiques ou prothétiques, seront envisagées de manière systématique en fonction de la situation clinique initiale. En effet, une bonne analyse est impérative pour le choix de la technique optimale. [less ▲]

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See detailReconstruction de paramètres environnementaux à l'aide des GNSS: une opportunité pour les entreprises
Warnant, René ULg

Conference given outside the academic context (2010)

Detailed reference viewed: 19 (2 ULg)
See detailLa reconstruction entre l'Etat et la société
Poncelet, Marc ULg; De Herdt, Tom

in De Herdt, Tom (Ed.) A la recherche de l'Etat en République démocratique du Congo (2011)

An empirical attempt to see post-conflict state reconstruction (DRC) as interaction game between weak governance and administration on one hand and popular or non state actors on the other hand.

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See detailReconstruction mammaire immédiate et radiothérapie post-opératoire : une mise au point
NARDELLA, Daniele ULg; LAUNGANI, Alexis ULg; LIFRANGE, Eric ULg et al

in Revue Médicale de Liège (2011), 66(5-6), 368-361

La reconstruction mammaire est actuellement partie intégrante de la prise en charge du cancer du sein. Lorsqu’elle est proposée en immédiat, plusieurs contraintes se présentent au chirurgien plasticien ... [more ▼]

La reconstruction mammaire est actuellement partie intégrante de la prise en charge du cancer du sein. Lorsqu’elle est proposée en immédiat, plusieurs contraintes se présentent au chirurgien plasticien. La prise en charge des patientes devant bénéficier d’une mastectomie se complique par les traitements complémentaires de radiothérapie. Nous proposons, dans ce travail, une prise en charge multidisciplinaire des patientes en les adressant à des sous-groupes spécifiques. Une reconstruction immédiate sera proposée à certaines patientes compte tenu des traitements complémentaires par radiothérapie. Les choix d’orientation sont complexes et une littérature pauvre à ce sujet ne nous permet pas d’orienter de façon systématique toutes les patientes. De nouvelles études, notamment prospectives, sont nécessaires pour orienter les patientes désirant une reconstruction immédiate associée à une radiothérapie post-mastectomie. [less ▲]

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See detailReconstruction mammaire microchirurgicale: pour qui et comment?
DEZFOULIAN, Bahram ULg; Nelissen, X.; Cusumano, P. et al

in Revue Médicale de Liège (2011), 66(5-6), 351-7

Breast reconstruction is now an integral part of breast cancer treatment. There are several different procedures that make use of flaps or prostheses, or a combination of the two. Which of these ... [more ▼]

Breast reconstruction is now an integral part of breast cancer treatment. There are several different procedures that make use of flaps or prostheses, or a combination of the two. Which of these procedures is indicated depends on the sequelae of the initial treatment and the patient's wishes and morphology. However, the constraints caused by the prosthetic material and the now regular use of microsurgical techniques have greatly favoured the purely autologous options. The different surgical techniques and their respective advantages and disadvantages will be described, before considering the timing of the various stages of the procedure. We will also give a summary of our experience with free flaps. [less ▲]

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Peer Reviewed
See detailLa reconstruction mammaire
Brewaeys, P.; Heymans, O.; Nizet, Jean-Luc ULg

in Revue Médicale de Liège (1998), 53(8), 483-9

Breast reconstruction has been the subject of many controversies. It now seems generally agreed however that the operation has no deleterious influence on the follow up of breast cancer patients and that ... [more ▼]

Breast reconstruction has been the subject of many controversies. It now seems generally agreed however that the operation has no deleterious influence on the follow up of breast cancer patients and that it has favorable psychologic effects. Breast reconstruction can be performed either by using prostheses or analogous tissues. These two different modalities have each their own advantages and limitations. Deep knowledge of the techniques and their indications allows to select the most appropriate approach in the individual patient and, thus, to improve long term results. [less ▲]

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See detailReconstruction of a Human Mitochondrial Complex I Mutation in the Green Microalga Chlamydomonas
Remacle, Claire ULg

in Mitochondria in life, death and disease (2012, May)

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See detailReconstruction of a human mitochondrial complex I mutation in the unicellular green alga Chlamydomonas.
Larosa, Véronique ULg; Coosemans, Nadine ULg; Motte, Patrick ULg et al

in Plant Journal (The) (2012), 70

Defects in complex I (NADH:ubiquinone oxidoreductase) are the most frequent cause of human respiratory disorders. The pathogenicity of a given human mitochondrial mutation can be difficult to demonstrate ... [more ▼]

Defects in complex I (NADH:ubiquinone oxidoreductase) are the most frequent cause of human respiratory disorders. The pathogenicity of a given human mitochondrial mutation can be difficult to demonstrate because the mitochondrial genome harbors large numbers of polymorphic base changes that have no pathogenic significance. In addition, mitochondrial mutations are usually found in the heteroplasmic state, which could hide the biochemical effect of the mutation. We propose that the unicellular green alga Chlamydomonas could be used to study such mutations because (1) respiratory-deficient mutants are viable and mitochondrial mutations are found in the homoplasmic state, (2) transformation of the mitochondrial genome is feasible, (3) Chlamydomonas complex I is close to that of humans. To illustrate that, we have introduced a Leu157Pro substitution in the Chlamydomonas ND4 subunit of complex I of two different recipient strains by biolistic transformation, demonstrating that site-directed mutagenesis of the Chlamydomonas mitochondrial genome is possible. This substitution did not lead to any respiratory enzyme defect when it is present in the heteroplasmic state in a patient presenting chronic progressive external ophthalmoplegia. When present in the homoplasmic state in the alga, the mutation does not prevent the assembly of the 950 kDa whole complex I which conserves nearly all the NADH dehydrogenase activity of the peripheral arm. However, the NADH:duroquinone oxidoreductase activity is strongly reduced, suggesting that the substitution could affect ubiquinone fixation to the membrane domain. The in vitro defects are correlated in vivo with a decrease in dark respiration and growth rate. [less ▲]

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See detailThe reconstruction of an Atlantic salmon population in the Belgian River Meuse basin. First success and new threats.
Philippart, Jean-Claude ULg; Ovidio, Michaël ULg; Frank, Vincent et al

Conference (2005, April)

A 'Meuse Salmon' project aiming at restoring an Atlantic salmon run in the River Meuse basin was put forward in 1983 (after the discovery of several 'sea trout' in the Meuse near Liège) and started ... [more ▼]

A 'Meuse Salmon' project aiming at restoring an Atlantic salmon run in the River Meuse basin was put forward in 1983 (after the discovery of several 'sea trout' in the Meuse near Liège) and started officially in 1987 as a contribution of Wallonia to the European Year of Environment. In the course of this programme, most dams (3-8 m in height) obstructing the canalised River Meuse in Belgium and The Netherlands have been fitted with modern fish-ways in order to restore the free circulation of diadromous fish species. A second facet of the Salmon Meuse programme consisted in restocking salmonid streams in the Belgian Ardennes with hatchery reared salmon parr and smolt (maximum 200.000 fish per year) from foreign origins (Scotland, Ireland and France). Returning adult salmon have been scientifically recorded in the Meuse in The Netherlands (estuary and lower course) since 1994 but only since the year 2002 in Belgium: 13 (61-79 cm FL) fish in 2002 and 2 (71-76 cm FL) fish in 2003 caught mostly (13 fish) in a new big fish-pass at the Visé-Lixhe dam and (2 fish) in the River Berwinne, a small tributary of the Meuse known as the last spawning place for S. salar in Belgium in the 1920's. Female and male returning salmon in 2002 were successfully artificially reproduced in order to build a captive freshwater brood stock to be used for production of parrs and smolts of the new Meuse strain next autumn. The communication briefly reports on the progress of the program as concerns the salmon culture for stocking in Wallonia, the population dynamics of stocked parrs in nursery rivers, the patterns of upstream and downstream migration of salmon in the Belgian Meuse and its tributaries and the new challenges to meet (impact on salmon of rising water temperature, development of power generation, increasing predation on smolts by piscivorous birds). [less ▲]

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See detailREconstruction of COLOUR scenes
Sirjacobs, Damien ULg; Alvera Azcarate, Aïda ULg; Barth, Alexander ULg et al

Poster (2008, February 12)

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See detailReconstruction of glottic defects after endoscopic cordectomy: voice outcome.
Remacle, Marc; Lawson, Georges; Morsomme, Dominique ULg et al

in Otolaryngologic Clinics of North America (2006), 39(1), 191-204

Medialization thyroplasty for correction of glottic gap, keel placement after laser-assisted section, and topical application of mitomycin-C for anterior glottic synechiae are effective procedures for ... [more ▼]

Medialization thyroplasty for correction of glottic gap, keel placement after laser-assisted section, and topical application of mitomycin-C for anterior glottic synechiae are effective procedures for voice restoration after endoscopic cordectomy. Only a minority of patients (16.4% of the authors’ patients after total or extended cordectomies) request this voice restoration. In this regard, self-evaluation questionnaires (eg, VHI) probably are the most useful tools, along with stroboscopy, for voice assessment. Careful elevation of the fibrous tissue from the inner surface of the thyroid cartilage is a tedious and lengthy step, but is critical in successful medialization after cordectomy; therefore, general anesthesia is preferable. Transoral keel placement is still advisable in cases of thick synechiae. The Lichtenberger technique has been a major advancement to the transoral approach, and is the preferred technique of the authors. [less ▲]

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See detailReconstruction of incomplete oceanographic data sets using empirical orthogonal functions: application to the Adriatic Sea surface temperature
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Rixen, Michel et al

in Ocean Modelling (2005), 9(4), 325-346

A method for the reconstruction of missing data based on an EOF decomposition has been applied to a large data set, a test case of Sea Surface Temperature satellite images of the Adriatic Sea. The EOF ... [more ▼]

A method for the reconstruction of missing data based on an EOF decomposition has been applied to a large data set, a test case of Sea Surface Temperature satellite images of the Adriatic Sea. The EOF decomposition is realised with a Lanczos method, which allows optimising computational time for large matrices. The results show that the reconstruction method leads to accurate reconstructions as well as a low cpu time when dealing with realistic cases. The method has been tested with different amounts of missing data, artificially adding clouds ranging from 40% to 80% of data loss, and then compared to the same data set with no missing data. A comparison with in situ data has also been made. These validation studies show that results are robust, even when the amount of missing data is very high. The reconstruction of the data from the Adriatic Sea shows realistic features and a reliable temperature distribution. In addition, the method is compared to an Optimal Interpolation reconstruction. The results obtained with both methods are very similar. The main difference is the computational time, which is reduced nearly 30 times with the method presented here. Once the reconstruction has been performed, the EOF decomposition is analysed to show the method's reliability, and a cold event on the Albanian coast is studied. The reconstructed data reflect the effect of wind on the Albanian coast, that led to a cold-water episode in this zone for a 6-day period. (c) 2004 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 145 (32 ULg)
See detailReconstruction of incomplete satellite images in the Adriatic Sea. Study of an upwelling in the Albanian coast
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Rixen, M. et al

Conference (2004)

Clouds in satellite images are a common problem. When working with these data is often desirable, if not necessary, to have complete fields. A method for the reconstruction of missing data in large data ... [more ▼]

Clouds in satellite images are a common problem. When working with these data is often desirable, if not necessary, to have complete fields. A method for the reconstruction of missing data in large data sets (Beckers and Rixen 2003, Alvera-Azcárate et al, 2004) is presented. The method, called DINEOF (Data INterpolating Empirical Orthogonal Functions), calculates the missing data from an optimal number of EOFs determined by cross-validation. A Lanczos method has been used for the EOF decomposition, in order to work with large matrices. In this work we present the reconstruction of a cloudy set of AVHRR SST satellite images of the Adriatic Sea. The results obtained are robust, as can be seen when comparing them to in situ observations [CTD profiles from MEDAR/Medatlas database (Medar Group, 2002)]. The results of the reconstruction are analysed, in particular a cold water event in the Albanian coast. This kind of event can be due to the action of winds, namely the Bora wind. Temporal EOFs and surface winds from ECMWF 40 years reanalysis are used to study this event. [less ▲]

Detailed reference viewed: 26 (2 ULg)
See detailReconstruction of missing data in geophysical fields. resolution of moving patterns
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Rixen, M. et al

Conference (2004)

A method for the reconstruction of missing data in large data sets is presented. The method, DINEOF (Data INterpolating Empirical Orthogonal Functions), calculates the missing data from an optimal number ... [more ▼]

A method for the reconstruction of missing data in large data sets is presented. The method, DINEOF (Data INterpolating Empirical Orthogonal Functions), calculates the missing data from an optimal number of EOFs determined by cross-validation. A Lanczos method has been used for the EOF decomposition, in order to work with large matrices. DINEOF has been applied to two data sets of sea surface temperature: a set of 105 images in the Adriatic Sea and a set of 216 images in Tanganyika Lake. These data sets present 52% and 37% of missing data respectively, due to cloud coverage. Several validation studies have been carried out: comparison with in situ data and reconstruction of increasing amounts of missing data, from 40% to 80% of the total data, by artificially adding clouds. All tests show that results are robust. DINEOF uses a classical EOF decomposition. In this work we also present a different EOF decomposition, known as Extended EOF (ExEOF) or Singular Spectrum Analysis (SSA). This technique consists in using a lagged version of the matrix being analysed. By taking into account both the spatial and temporal correlation of the data, the ExEOF technique resolves spatio-temporal moving patterns in a more accurate way. Preliminary results show that this technique helps to better reconstruct the missing data in our data sets. [less ▲]

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Peer Reviewed
See detailReconstruction of missing data in satellite and in situ data sets with DINEOF (Data Interpolating Empirical Orthogonal Functions)
Alvera Azcarate, Aïda ULg; Barth, Alexander ULg; Beckers, Jean-Marie ULg

Conference (2010, July 12)

DINEOF (Data Interpolating Empirical Orthogonal Functions), a method to reconstruct missing data in geophysical data sets, is presented. Based on a truncated Empirical Orthogonal Functions (EOF) basis ... [more ▼]

DINEOF (Data Interpolating Empirical Orthogonal Functions), a method to reconstruct missing data in geophysical data sets, is presented. Based on a truncated Empirical Orthogonal Functions (EOF) basis, DINEOF uses an iterative procedure to calculate the values at the missing locations. A clear advantage of DINEOF is that no aprioriate knowledge about the statistics of the data set being reconstructed is needed (such as covariance or correlation length): the EOF basis is used internally to infer necessary information about the data, so no estimation of those parameters is needed. This characteristic is specially interesting for heterogeneous data distributions for which is difficult to derive this information. Also obtained are estimations of the error covariance of the reconstructed field, and outliers, i.e. data that present anomalous values with respect to the surrounding information in the original data, for which the residuals are larger than the statistically expected misfit calculated during the analysis. When very few data is available, the estimated covariance between two successive images used in the EOF calculation might not sufficiently robust. As a consequence, spikes appear in the temporal EOFs, which result in unrealistic discontinuities in the reconstruction. A temporal filter has been applied to the covariance matrix used to determined the EOFs, which effectively enhance temporal continuity. This has been applied to a SST data set of the Black Sea and the reconstruction error is estimated by cross-validation. On-going work includes the development of a merging capability within DINEOF that will allow to blend data from different platforms (satellite and in situ data). [less ▲]

Detailed reference viewed: 15 (2 ULg)