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See detailFault Diagnosis in Industrial Systems Based on Blind Source Separation Techniques Using One Single Vibration Sensor
Nguyen, Viet Ha ULiege; Rutten, Christophe ULiege; Golinval, Jean-Claude ULiege

in Maia NNM, Neves MM (Ed.) International Conference on Structural Engineering Dynamics (ICEDyn 2011) - Proceedings (2011)

In the field of structural health monitoring or machine condition monitoring, most vibration based methods reported in the literature require to measure responses at several locations on the structure. In ... [more ▼]

In the field of structural health monitoring or machine condition monitoring, most vibration based methods reported in the literature require to measure responses at several locations on the structure. In machine condition monitoring, the number of available vibration sensors is often small and it is not unusual that only one single sensor is used to monitor a machine. The aim of this paper is to propose an extension of fault detection techniques that may be used when a reduced set of sensors or even one single sensor is available. Fault detection techniques considered here are based on output-only methods coming from the Blind Source Separation (BSS) family, namely Principal Component Analysis (PCA) and Second Order Blind Identification (SOBI). The advantages of PCA or SOBI rely on their rapidity of use and their reliability. Based on these methods, subspace identification may be performed by using the concept of block Hankel matrices which make possible the use of only one single measurement signal. Thus, the problem of fault detection in mechanical systems can be solved by using subspaces built from active principal components or modal vectors. It consists in comparing subspace features between the reference (undamaged) state and a current state. The angular coherence between subspaces is a good indicator of a dynamic change in the system due to the occurrence of faults or damages. The robustness of the methods is illustrated on industrial examples. [less ▲]

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See detailFault re-activation, stress interaction and rupture propagation of the 1981 Corinth earthquake sequence
Hubert, Aurelia ULiege; King, G. C. P.; Armijo, R. et al

in Earth and Planetary Science Letters (1996), 142

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See detailFauna vs flora contribution to the leaf epiphytes biomass in a Posidonia oceanica seagrass bed (Revellata Bay, Corsica).
Lepoint, Gilles ULiege; Havelange, Stéphane; Gobert, Sylvie ULiege et al

in Hydrobiologia (1999), 394

The epiphyte biomass of Posidonia oceanica (L.) Delile leaves is mainly related to the substrate leaf availability. It decreases with increasing depth and increases from winter to summer, following the ... [more ▼]

The epiphyte biomass of Posidonia oceanica (L.) Delile leaves is mainly related to the substrate leaf availability. It decreases with increasing depth and increases from winter to summer, following the leaf biomass changes. In Revellata Bay (Gulf of Calvi, Corsica), at shallow depth (10m in this study) where photophilous algae grow, the fixed epifauna biomass accounts for about one third of leaf epiphytes biomass. At deeper depths in the Revellata Bay (20 and 30m), where shade-tolerant algae are dominant among epiflora, epifauna may account for more than half the leaf epiphytes biomass. [less ▲]

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See detailFaunal/floral and isotopic responses to Milankovitch precession cycles and environmental changes in the upper Gulpen Formation (Upper Maastrichtian) at the CBR-Lixhe and ENCI-Maastricht bv quarries
Felder, P. J.; Keppens, E.; De Clercq, Bernadette ULiege et al

in Netherlands Journal of Geosciences-Geologie en Mijnbouw (2003), 82(3), 275-281

Two sections, just below the Nivelle Horizon in the upper Gulpen Formation (Upper Maastrichtian), and seven kilometres apart (CBR-Lixhe and ENCI-Maastricht bv quarries) have been analysed (samples every 5 ... [more ▼]

Two sections, just below the Nivelle Horizon in the upper Gulpen Formation (Upper Maastrichtian), and seven kilometres apart (CBR-Lixhe and ENCI-Maastricht bv quarries) have been analysed (samples every 5 cm) for dinocyst, pollen grains and bioclast contents as well as for carbon and oxygen isotopic composition, to obtain better insight into the influence of weathering on these sediments. The CBR section lies above groundwater level, while that at the ENCI quarry is some metres below. At the former quarry we recognised the influences of weathering (karst) nearby. At ENCI, palynological, bioclast and stable isotope results of the carbonate phase (mainly consisting of coccoliths) co-vary remarkably, displaying two cycles which may be interpreted tentatively as climatic fluctuations. The partial derivative(18)O curve varies roughly between -1.6parts per thousand and -1.1parts per thousand (on PDB scale), corresponding to a temperature change of about 2degreesC. Less negative values (i.e. cooler seawater) coincide with larger amounts of pollen of Normapolles and Triporates type assumed to represent temperate forest elements of a vegetation also containing tropical elements such as palms. Assuming the 5 cm sample intervals at ENCI to correspond to 1 ka, climatic maxima (and minima) may be 20-25 ka apart, obviously recalling Milankovitch precession cycles. These are independent of a sharp sedimentological change noted in the upper part of the lowest cycle (samples 42 to 24). Upwards of sample 42, bioclast contents increase and dinocysts, Spiniferites in particular, decrease significantly, corresponding to a marked shallowing. This turning point is also recorded in the partial derivative(13)C curve at ENCI. Bioclast percentages appear to follow composite trends that are influenced by both climatic and sedimentological conditions. [less ▲]

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See detailLa faune de la Meuse belge
Damas, Hubert ULiege

in 63ème session de l'association française pour l'avancement des sciences, Liège, 1939 (1941)

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See detailFaune entomologique du Grand-Duché de Luxembourg : III : Cantharoidea (col.)
Magis, Noël ULiege

in Archives de l'Institut grand-ducal de Luxembourg. Section des sciences naturelles, physiques et mathématiques (1956), XXIII

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See detailFaune entomologique glaciaire du plateau de la Baraque Michel
Fredericq, Léon ULiege

in La Terre Wallone : catalogue régionaliste (1924)

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See detailFaune et flore de la Formation de Sika (Dévonien inférieur) dans la presqu'île de Dô Son (Viêt-Nam).
Janvier, Philippe; Blieck, Alain; Gerrienne, Philippe ULiege et al

in Bulletin du Museum National d’Histoire Naturelle (1987), 92(3), 291-301

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See detailLa faune et la flore glaciaires du plateau de la Baraque-Michel (point culminant de l'Ardenne)
Fredericq, Léon ULiege

in Bulletin de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique. Sciences (1904)

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See detailFaune médiévale et post-médiévale du château de Franchimont (Theux)
Gautier, Achilles; Vanguestaine, Marie; Hoffsummer, Patrick ULiege

in Vie archéologique (2005), 64

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See detailLa faune sauvage, réservoir potentiel de maladies transmissibles à l’homme
Linden, Annick ULiege

Conference (2010, March)

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See detailFaunistique des macrophyini de la Belgique et du Grand-Duché de Luxembourg (Hyménoptères : Tenthredinidae) : 1. Genre Pachyprotasis Hartig, 1837
Magis, Noël ULiege

in Bulletin de la Société Royale des Sciences de Liège (1984), 53(5), 327-339

Le genre Pachyprothasis HARTIG est représenté en Belgique et au Grand-Duché de Luxembourg par quatre des cinq espèces vivant en Europe. L'analyse de l'information disponible démontre que P. simulans (KLUG ... [more ▼]

Le genre Pachyprothasis HARTIG est représenté en Belgique et au Grand-Duché de Luxembourg par quatre des cinq espèces vivant en Europe. L'analyse de l'information disponible démontre que P. simulans (KLUG) et P. variegata (FALLEN) ont toujours été des espèces rares dans la dition. P. antennata (KLUG) y était plus prospère jusqu'en 1949 et doit être considérée aujourd'hui comme étant en régression. P. rapae (LINNE) est de très loin l'espèce la plus abondante, la plus fréquente et la plus répandue dans les deux pays. L'analyse des dates de récolte montre que cette dernière est bivoltine; cette caractéristique biologique la distingue des trois autres. Le recensement des plantes-hôtes montre que les larves des quatre espèces doivent toute êtres classées parmi les polyphages du premier degré. [less ▲]

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See detailFaunistique des macrophyini de la Belgique et du Grand-Duché de Luxembourg (Hyménoptères : Tenthredinidae) : 2. Généralités sur le genre Macrophya DAHLBOM; inventaire des espèces apparentées à M. albicincta (SCHRANK)
Magis, Noël ULiege

in Bulletin de la Société Royale des Sciences de Liège (1984), 53(6), 437-449

The species belonging to the epinota-group of Macrophya DAHLBOM, living in Belgium and Grand Duchy of Luxembourg have been inventoried. A key for their identification is given. Some aspects of the ... [more ▼]

The species belonging to the epinota-group of Macrophya DAHLBOM, living in Belgium and Grand Duchy of Luxembourg have been inventoried. A key for their identification is given. Some aspects of the variability (coloration of scutellum, dimensions of wing's veins) between M. albicincta (SCHRANK) and M. alboannulata COSTA are analysed and compared with results obtained in France. This variability is perhaps of clinal type. From faunistical point of view, the geographical repartition, the phenology and the relative frequency of all species are related. [less ▲]

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See detailFaunistique des macrophyini de la Belgique et du Grand-Duché de Luxembourg (Hyménoptères : Tenthredinidae) : 3. Les Macrophya des groupes blanda-duodecimpunctata et chrysura
Magis, Noël ULiege

in Bulletin de la Société Royale des Sciences de Liège (1985), 54(1), 45-54

The chorology of the Macrophya DALHBOM, belonging to the blanda-duodecimpunctata (4 spec.) and to the chrysura group (2 spec.) respectively, is described in Belgium and Great-Duchy of Luxembourg. The ... [more ▼]

The chorology of the Macrophya DALHBOM, belonging to the blanda-duodecimpunctata (4 spec.) and to the chrysura group (2 spec.) respectively, is described in Belgium and Great-Duchy of Luxembourg. The phenology of these species is recorded. Comparison of data obtained in Belgium before and after 1950 indicates a regression of M. blanda (FABRICIUS) and M. diversipes (SCHRANK). M. erythrocnema COSIA and M. recognata ZOMBORI have been discovered only 20 years ago, they appear to be recent immigrants in the country. M. recognata so far known from 5 localities, seems most able to take root as M. erythrocnema. [less ▲]

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See detailFaunistique des macrophyini de la Belgique et du Grand-Duché de Luxembourg (Hyménoptères : Tenthredinidae) : 4. Les Macrophya du groupe postica et les autres Macrophya s. str.; le sous-genre Pseudomacrophya ENSLIN, 1913.
Magis, Noël ULiege

in Bulletin de la Société Royale des Sciences de Liège (1985), 54(3), 149-159

The geographical distribution, the phenology and the prosperity's level of six Macrophya species living in Belgium and Grand Duchy of Luxembourg are described and discussed. The available data support the ... [more ▼]

The geographical distribution, the phenology and the prosperity's level of six Macrophya species living in Belgium and Grand Duchy of Luxembourg are described and discussed. The available data support the hypothesis that M. militaris (KLUG) and M. rufipes (LINNE) are less prosperous actually than before 1950. [less ▲]

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See detailFaunistique des Macrophyini de la Belgique et du Grand-Duché de Luxembourg (Hyménoptères : Tenthredinidae) : 5. Conclusions générales
Magis, Noël ULiege

in Bulletin de la Société Royale des Sciences de Liège (1985), 54(6), 363-371

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See detailFaunistique et écologie chimique des peuplements benthiques sur substrats durs et des sédiments de la baie de Calvi (Corse)
Jeuniaux, Charles ULiege

in Bulletin de la Société Royale des Sciences de Liège (1981), 50(11-12), 446-452

A research program on mediterranean benthos ecology going on in Calvi (Corsica) is presented. The first goal of this program is the characterisation of different benthic marine biocenoses by some chemical ... [more ▼]

A research program on mediterranean benthos ecology going on in Calvi (Corsica) is presented. The first goal of this program is the characterisation of different benthic marine biocenoses by some chemical parameters, such as chitin, cellulose and total protein biomass. The fate of mollusc shell fragments in organoclastic sediments is then followed by the observation of ultrastructural modifications and by measuring the chitin degradation and the alteration of mineral constituents due to the activity of endobiotic organisms. A further aspect of this program is the study of a benthic community of 3 Turritella species and some cavernicolous Sipunculids and hermit crabs. [less ▲]

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See detailFaussair(cl)es
Dupont, Pascal ULiege

in Losanges (2010), 8

A quarter circle can be well approximated by a Bézier curve of order 3. The best way to fit this approximation to the quarter circle is studied.

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