Browsing
     by title


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

or enter first few letters:   
OK
Full Text
See detailHuy / Ben Ahin : sondage dans l'abri de "Werleu II"
Noiret, Pierre ULg

in Chronique de l'Archéologie Wallonne (2013), 20

Detailed reference viewed: 37 (2 ULg)
Full Text
See detailHuy / Ben Ahin : sondage dans le "Grand Abri"
Noiret, Pierre ULg; Flas, Damien ULg

in Chronique de l'Archéologie Wallonne (2013), 20

Detailed reference viewed: 58 (5 ULg)
See detailHuybrechts, Albert
Pirenne, Christophe ULg

in Nouvelle Biographie Nationale (1999)

Detailed reference viewed: 11 (5 ULg)
Full Text
Peer Reviewed
See detailHuygens attitude reconstruction based on flight engineering parameters
Perez-Ayucar, Miguel; Sarlette, Alain ULg; Couzin, Patrice et al

Conference (2005, June)

Huygens is ESA’s main contribution to the joint NASA/ESA/ASI Cassini/Huygens mission to Saturn and its largest moon Titan. The Probe, delivered to the interface altitude of 1270 km above the surface by ... [more ▼]

Huygens is ESA’s main contribution to the joint NASA/ESA/ASI Cassini/Huygens mission to Saturn and its largest moon Titan. The Probe, delivered to the interface altitude of 1270 km above the surface by NASA/JPL Cassini orbiter, entered the dense atmosphere of Titan on 14 January 2005 and landed on the surface after a descent under parachute of slightly less than 2.5 hours. Huygens continued to function after landing for more than 3 hours. Data was transmitted and successfully recovered by Cassini continuously during the parachute descent and for 72 minutes on the surface. Although the Huygens attitude reconstruction based on the flight engineering parameters was not foreseen during the development phase (no gyros were included), a rough descent under parachute and indications of an anomaly in the probe spin direction make the engineering dataset valuable in the frame of the ADRS (Huygens Attitude Determination and Reconstruction Subgroup) as a complement to the scientific measurements. In addition, several scientific teams have a strong interest in understanding the orientation of the probe for interpreting their data, as DISR (Descent Imager and Spectral Radiometer) and HASI-PWA (Huygens Atmospheric Structure Instrument-Permeability, Wave and Altimetry). In this paper we describe the engineering parameters used for the Probe attitude reconstruction (Clausen et al., 2002), namely the radio link AGC (Automatic Gain Control), RASU and CASU (Radial and Central Accelerometer Sensor Units) and RAU (Radar Altimeter Unit). We explain the methodology applied to indirectly infer the attitude information from the measurements of these sensors. We also discuss and present the reconstructed information related to attitude: spin rate and azimuthal position (during the atmospheric descent), and landing orientation. Tip and tilt implications are still being worked at the time of writing. Preliminary data on their behavior is presented. [less ▲]

Detailed reference viewed: 73 (1 ULg)
Peer Reviewed
See detailHuysmans avec Schopenhauer. Le pessimisme d'A rebours
Steinmetz, Rudy ULg

in Romantisme (1988)

Detailed reference viewed: 73 (1 ULg)
Full Text
Peer Reviewed
See detailHVDC control strategies to improve transient stability in interconnected power systems
Hazra, Jagabondhu; Phulpin, Yannick; Ernst, Damien ULg

in Proceedings of the 2009 IEEE Bucharest PowerTech (2009)

This paper presents three HVDC modulation strategies to improve transient stability in an interconnected power system. AC variables such as rotor speeds, voltage phasors, and tieline power flows are used ... [more ▼]

This paper presents three HVDC modulation strategies to improve transient stability in an interconnected power system. AC variables such as rotor speeds, voltage phasors, and tieline power flows are used as input to the controller that modifies the power flow settings through the HVDC-links. The proposed techniques are tested on the IEEE 24-Bus reliability test system and critical clearing times obtained for several contingencies are analyzed. The paper shows that HVDC modulation can lead to substantial improvement in transient stability. [less ▲]

Detailed reference viewed: 147 (7 ULg)
Full Text
Peer Reviewed
See detailHyaluronan for knee osteoarthritis: an updated meta-analysis of trials with low risk of bias
Richette, P.; Chevalier, X.; Ea, H. K. et al

in RMD Open (2015), 1(1), 000071

BACKGROUND: The effectiveness of intra-articular hyaluronic acid (IAHA) injection for knee osteoarthritis (KOA) is debated. OBJECTIVES: To evaluate the effect of IAHA for patients with KOA by analysing ... [more ▼]

BACKGROUND: The effectiveness of intra-articular hyaluronic acid (IAHA) injection for knee osteoarthritis (KOA) is debated. OBJECTIVES: To evaluate the effect of IAHA for patients with KOA by analysing data from trials of IAHA versus placebo with low risk of bias, to provide the highest level of evidence. METHODS: A systematic review and meta-analysis was conducted. Randomised controlled trials (RCTs) with a low risk of bias (adequate randomisation and concealment and double-blind design) that investigated IAHA versus placebo (saline solution) injection were eligible. The primary efficacy measure was pain intensity and secondary outcome function at 3 months. The treatment effect was summarised with the standardised mean difference (SMD) calculated from differences in means of pain and function measures between treatment and control groups at 3 months. Trials were pooled by a random-effects model with DerSimonian and Laird weights. Statistical heterogeneity was explored by a visual exploration of forest plots and the I(2) statistic. RESULTS: A total of eight RCTs (2 199 randomised patients) met our inclusion criteria. IAHA significantly reduced the pain intensity (SMD=-0.21, 95% CI (95% CI) -0.32 to -0.10) and improved function (SMD=-0.12, 95% CI -0.22 to -0.02). Trials showed no heterogeneity. CONCLUSIONS: This meta-analysis of high-quality trials of IAHA versus placebo shows that IAHA provides a moderate but real benefit for patients with KOA. [less ▲]

Detailed reference viewed: 8 (0 ULg)
Full Text
Peer Reviewed
See detailHyaluronan Metabolism in Human Keratinocytes and Atopic Dermatitis Skin Is Driven by a Balance of Hyaluronan Synthases 1 and 3
Malaisse; Bourguignon, Virginie; De Vuyst, Evelyne et al

in Journal of Investigative Dermatology (2014), 134

Hyaluronan (HA) is a glycosaminoglycan synthesized directly into the extracellular matrix by three hyaluronan synthases (HAS1, HAS2, and HAS3). HA is abundantly synthesized by keratinocytes but its ... [more ▼]

Hyaluronan (HA) is a glycosaminoglycan synthesized directly into the extracellular matrix by three hyaluronan synthases (HAS1, HAS2, and HAS3). HA is abundantly synthesized by keratinocytes but its epidermal functions remain unclear. We used culture models to grow human keratinocytes as autocrine monolayers or as reconstructed human epidermis (RHE) to assess HA synthesis and HAS expression levels during the course of keratinocyte differentiation. In both the models, epidermal differentiation downregulates HAS3 mRNA expression while increasing HAS1 without significant changes in hyaluronidase expression. HA production correlates with HAS1 mRNA expression level during normal differentiation. To investigate the regulation of HAS gene expression during inflammatory conditions linked to perturbed differentiation, lesional and non-lesional skin biopsies of atopic dermatitis (AD) patients were analyzed. HAS3 mRNA expression level increases in AD lesions compared with healthy and non-lesional skin. Simultaneously, HAS1 expression decreases. Heparin-binding EGF-like growth factor (HB-EGF) is upregulated in AD epidermis. An AD-like HAS expression pattern is observed in RHE incubated with HB-EGF. These results indicate that HAS1 is the main enzyme responsible for HA production by normal keratinocytes and thus, must be considered as an actor of normal keratinocyte differentiation. In contrast, HAS3 can be induced by HB-EGF and seems mainly involved in AD epidermis [less ▲]

Detailed reference viewed: 36 (3 ULg)
Full Text
Peer Reviewed
See detailHyaluronic acid and tendon lesions
Kaux, Jean-François ULg; SAMSON, Antoine; Crielaard, Jean-Michel ULg

in Muscles, Ligaments and Tendons Journal (2016), 5(4 (eCollection 2015 Oct-Dec)), 264-269

Introduction: Recently, the viscoelastic properties of hyaluronic acid on liquid connective tissue have been proposed for the treatment of tendinopathies. Some fundamental studies show encouraging results ... [more ▼]

Introduction: Recently, the viscoelastic properties of hyaluronic acid on liquid connective tissue have been proposed for the treatment of tendinopathies. Some fundamental studies show encouraging results on hyaluronic acid’s ability to promote tendon gliding and reduce adhesion as well as to improve tendon architectural organisation. Some observations also support its use in a clinical setting to improve pain and function. This literature review analyses studies relating to the use of hyaluronic acid in the treatment of tendinopathies. Methods: This review was constructed using the Medline database via Pubmed, Scopus and Google Scholar. The keywords hyaluronic acid, tendon and tendinopathy were used for the research. Results: In total, 27 articles (in English and French) on the application of hyaluronic acid to tendons were selected for their relevance and scientific quality, including eight for the 'in vitro' part, three for the 'in vivo' animal part and six for the human section. Conclusions: Preclinical studies demonstrate encouraging results: HA permits tendon gliding, reduces adhesions, creates better tendon architectural organisation and limits inflammation. These laboratory observations appear to be supported by limited but encouraging short-term clinical results on pain and function. However, controlled randomised studies are still needed. [less ▲]

Detailed reference viewed: 50 (8 ULg)
Full Text
Peer Reviewed
See detailHybrid Acceleration using Real Vector Automata
Boigelot, Bernard ULg; Herbreteau, Frédéric; Jodogne, Sébastien ULg

in Lecture Notes in Computer Science (2003, July), 2725

This paper addresses the problem of computing an exact and effective representation of the set of reachable configurations of a linear hybrid automaton. Our solution is based on accelerating the state ... [more ▼]

This paper addresses the problem of computing an exact and effective representation of the set of reachable configurations of a linear hybrid automaton. Our solution is based on accelerating the state-space exploration by computing symbolically the repeated effect of control cycles. The computed sets of configurations are represented by Real Vector Automata (RVA), the expressive power of which is beyond that of the first-order additive theory of reals and integers. This approach makes it possible to compute in finite time sets of configurations that cannot be expressed as finite unions of convex sets. The main technical contributions of the paper consist in a powerful sufficient criterion for checking whether a hybrid transformation (i.e., with both discrete and continuous features) can be accelerated, as well as an algorithm for applying such an accelerated transformation on RVA. Our results have been implemented and successfully applied to several case studies, including the well-known leaking gas burner, and a simple communication protocol with timers. [less ▲]

Detailed reference viewed: 29 (4 ULg)
Full Text
Peer Reviewed
See detailHybrid adaptive observers for locally Lipschitz systems with application to mechanical oscillators
Bobtsov; Efimov, Denis ULg; Pyrkin, Anton

in Proc. IEEE Conf. Control Applications, Saint-Petersburg (2009)

Adaptive observer design procedure is proposed for nonlinear locally Lipschitz systems. Possible presence of disturbances is taken into account. The solution is based on logic-based control approach ... [more ▼]

Adaptive observer design procedure is proposed for nonlinear locally Lipschitz systems. Possible presence of disturbances is taken into account. The solution is based on logic-based control approach applicable to nonlinear systems with bounded solutions. Efficacy of the proposed observer is demonstrated by computer simulation for a mechanical oscil- lating system. [less ▲]

Detailed reference viewed: 23 (1 ULg)
Full Text
See detailHybrid AI
Hopgood, Adrian ULg

in ITNOW (2013), 55(4 / Winter), 10-11

Detailed reference viewed: 9 (1 ULg)
Peer Reviewed
See detailA hybrid approach for the inference and modelling of gene regulatory networks
Huynh-Thu, Vân Anh ULg; Sanguinetti, Guido

Conference (2014, September 06)

Detailed reference viewed: 17 (0 ULg)
Full Text
Peer Reviewed
See detailA hybrid bioregulatory model of angiogenesis during bone fracture healing
Peiffer, Veronique; Gerisch, Alf; Vandepitte, Dirk et al

in Biomechanics & Modeling in Mechanobiology (2011), 10(3), 383-395

Bone fracture healing is a complex process in which angiogenesis or the development of a blood vessel net work plays a crucial role. In this paper, a mathematicalmodel is presented that simulates the ... [more ▼]

Bone fracture healing is a complex process in which angiogenesis or the development of a blood vessel net work plays a crucial role. In this paper, a mathematicalmodel is presented that simulates the biological aspects of fracture healing including the formation of individual blood vessels. The model consists of partial differential equations, several of which describe the evolution in density of the most important cell types, growth factors, tissues and nutrients. The other equations determine the growth of blood vessels as a result of themovement of leading endothelial (tip) cells. Branching and anastomoses are accounted for in the model. The model is applied to a normal fracture healing case and subjected to a sensitivity analysis. The spatiotemporal evolution of soft tissues and bone, as well as the development of a blood vessel network are corroborated by comparison with experimental data. Moreover, this study shows that the proposed mathematical framework can be a useful tool in the research of impaired healing and the design of treatment strategies. [less ▲]

Detailed reference viewed: 78 (18 ULg)
See detailHybrid extended equal-area criterion for fast transient stability assessment with detailed power system models
Zhang, Y.; Rousseaux, Patricia ULg; Wehenkel, Louis ULg et al

in Proceedings of the IFAC Symposium on Control of Power Plants and Power Systems (1995)

Detailed reference viewed: 67 (0 ULg)
Full Text
Peer Reviewed
See detailThe Hybrid Finite Element Mixing Cell Method: A New Flexible Method for Modelling Mine Ground Water Problems
Brouyère, Serge ULg; Orban, Philippe ULg; Wildemeersch, Samuel ULg et al

in Mine Water & the Environment (2009), 28(2), 102-114

Dewatering operations often stop at mine closure. The ground water rebound can have undesirable consequences, which numerical models can help one understand and manage. However, classical modelling ... [more ▼]

Dewatering operations often stop at mine closure. The ground water rebound can have undesirable consequences, which numerical models can help one understand and manage. However, classical modelling techniques are relatively unsuitable to these contexts. While spatially-distributed and physically-based models suffer difficulties due to the lack of data and the complexity of geological and hydrogeological conditions, black-box models are too simple to deal with the problems effectively. A new modelling method is proposed to simulate ground water environments in which water flows through mined (exploited) and unmined (unexploited) areas. Exploited zones are simulated using a group of mixing cells possibly interconnected by pipes. Unexploited zones are simultaneously simulated using classical finite elements. This combined approach allows explicit calculation of ground water flows around the mine and mean water levels in the exploited zones. Water exchanges between exploited zones and unexploited zones are simulated in the model using specifically-defined internal boundary conditions. The method is tested on synthetic cases of increasing complexity, and first results from a real case study are presented. [less ▲]

Detailed reference viewed: 220 (60 ULg)
Full Text
Peer Reviewed
See detailThe Hybrid Finite-Element Mixing-Cell method: a candidate for modelling groundwater flow and transport in karst systems
Brouyère, Serge ULg; Wildemeersch, Samuel ULg; Orban, Philippe ULg et al

in Bertrand, C.; Carry, N.; Mudry, J. (Eds.) et al Proc. H2Karst, 9th Conference on Limestone Hydrogeology (2011, September)

Groundwater flow and contaminant transport modelling in karst systems remains a challenge because of the complexity of the geology made of caves, voids, conduits of various sizes and forms and interacting ... [more ▼]

Groundwater flow and contaminant transport modelling in karst systems remains a challenge because of the complexity of the geology made of caves, voids, conduits of various sizes and forms and interacting matrix. Such heterogeneous structures cause complex hydraulic conditions for groundwater flow and transport processes. Despite the progresses in field investigation techniques and experiments, detailed knowledge and characterization of the karst system geometry and connectivity remains inaccessible and pragmatic modelling approaches have to be used. Groundwater models of different complexities have been developed for karst systems, ranging from transfer functions and linear reservoir models to spatially distributed models. Here, a new flexible modelling approach, the Hybrid Finite-Element Mixing-Cell method (HFEMC), has been developed that allows combining in a single model, and in a fully interacting way, different mathematical approaches of various complexities for groundwater modelling in complex environments. This includes linear reservoirs, distributed reservoirs, groundwater flow in variably saturated equivalent porous media, with possibilities to consider by-pass flows along preferential flow paths, internal boundary conditions between the karstic features and the surrounding rock mass matrix background and drainage by surface waters. This method has been implemented in the groundwater flow and solute transport numerical code SUFT3D. The objective of this communication is to present the modelling concepts and to discuss the potentials and advantages of the HFEMC method for modelling groundwater flow in karst systems over existing more classical modelling approaches. The discussion is supported by illustrative “synthetic” examples representative of karst systems and a real modelling application to the case of groundwater rebound and water inrush in a closed underground coal mine which presents a very similar geometrical and hydrological context to a karst, with cavities, drains and interacting rock mass. [less ▲]

Detailed reference viewed: 69 (18 ULg)
Full Text
See detailThe Hybrid Finite-Element Mixing-Cell method: a new flexible method for large scale groundwater modelling
Orban, Philippe ULg; Brouyère, Serge ULg; Wildemeersch, Samuel ULg et al

Conference (2008)

Interest of end-users and policy makers for understanding and managing water systems at the regional scale has increased for years. At this scale, groundwater models of different complexity ranging from ... [more ▼]

Interest of end-users and policy makers for understanding and managing water systems at the regional scale has increased for years. At this scale, groundwater models of different complexity ranging from black-box models to physically based distributed models have been used in various hydrogeological conditions. Black-box models, such as transfer functions, have been applied for example to model groundwater in large scale hydrological models, to model karstic systems, in particular for the interpretation of isotopic data. Their concepts are simple and attractive because they require relatively few data. The main drawbacks are however that modelling results are not spatially distributed and their predictive capability is questionable due to the semi-empirical nature of process descriptions. On the contrary, due to a more advanced description of ongoing processes, physically-based distributed models are expected to have better predictive capabilities than black-box models. However, because such models require more data, they are generally applied for case studies that are better characterized from a hydrogeological point of view, for which the distribution of water levels or solute concentrations in the groundwater systems are needed. For large-scale modelling purposes, black-box models and physically-based distributed models have both proved their utilities and have their own justifications, advantages and disadvantages. However, few attempts have been made to combine the advantages of these two categories of approaches in a unified modelling application. A new flexible modelling approach, the Hybrid Finite-Element Mixing-Cell method (HFEMC), has been developed that allows combining in a single model, and in a fully integrated way, different mathematical approaches of various complexities for groundwater modelling in complex and large scale environments. This method has been implemented in the groundwater flow and solute transport numerical code SUFT3D. The approach has been first tested and illustrated using basic and advanced “synthetic” examples that allow validating and discussing its advantages over existing modelling concepts. The HFEMC approach is now applied for the development of a large scale groundwater flow and solute transport model in different groundwater basins in Belgium. [less ▲]

Detailed reference viewed: 139 (46 ULg)
Full Text
Peer Reviewed
See detailThe Hybrid Finite-Element Mixing-Cell method: a new flexible method for modelling mine water problems
Brouyère, Serge ULg; Orban, Philippe ULg; Wildemeersch, Samuel ULg et al

in Rapantova, N.; Hrkal, Z. (Eds.) Mine Water and the Environment Proceedings of IWMA 2008 (2008)

Mine closure is often accompanied by a stop in dewatering operations. This generally induces groundwater rebound in the mined rock system with short and long term consequences that may be disastrous: soil ... [more ▼]

Mine closure is often accompanied by a stop in dewatering operations. This generally induces groundwater rebound in the mined rock system with short and long term consequences that may be disastrous: soil instabilities such as landslides and subsidence reactivation, flooding, flooded basement and acid mine drainage. Modelling tools can be very advantageous and efficient in helping understanding and managing such problems, however, classical modelling approaches have proved to be relatively unsuited to such contexts. Because of the former mining operations, the underground geological system is strongly disturbed (excavated, fractured and collapsed zones, galleries, large shafts, etc.). Using complex spatially distributed modelling approaches such as 3D finite elements usually lead to strong difficulties related to the lack of data, the complexity of geological and hydrogeological conditions (complex geometry, non Darcian fluxes…). On the other hand, using a simplified approach such as black-box models often leads to oversimplification of the reality: particularly when interactions between the mined system and its surrounding geological and hydrogeological environment are very important. A new modelling approach is developed for simulation of the groundwater flow in such complex environments. It combines, in a single fully integrated simulator, a representation of the unmined area by a classical finite element modelling technique, together with conceptualisation of the worked areas and galleries by a group of mixing cells connected by pipes. The whole assembled groundwater flow model allows an accurate estimation and representation of (a) water infiltration (precipitations, river losses …) through the unsaturated zone reaching the exploited area (recharge of boxes) and (b) water exchanges with adjacent aquifers. The model can estimate the flow of groundwater in and around the minefield and the mean water level in the boxes. It is also capable of considering water exchanges between different mined zones, through connection pathways such as old roadways galleries and shafts. Modelling concepts and equations are described and illustrated using basic and advances validation examples. A real case application corresponding to an abandoned coalfield in the region of Liège (Belgium) is used to illustrate the suitability and efficiency of the approach. [less ▲]

Detailed reference viewed: 220 (33 ULg)