Publications ORBi OA
Bookmark and Share    
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 detailBases biologiques et éco-hydrauliques pour la restauration de la continuité piscicole en rivière : premier bilan et perspectives.
Ovidio, Michaël ULg; Philippart, Jean-Claude ULg; Orban, Patrice et al

in Forêt Wallonne (2009), 101(juillet-août), 18-29

Detailed reference viewed: 174 (54 ULg)
Full Text
See detailEntomologie Forensique: les insectes...pièces à conviction?
Dekeirsschieter, Jessica ULg; Haubruge, Eric ULg

Article for general public (2009)

Detailed reference viewed: 84 (25 ULg)
Full Text
See detailL'aide familiale, un maillon essentiel pour faire face aux situations de maltraitance de la personne âgée à domicile
Massart, Valérie ULg; Vanmeerbeek, Marc ULg; Denoël, Philippe et al

in Education Santé (2009), (247), 5-7

Detailed reference viewed: 126 (26 ULg)
Full Text
Peer Reviewed
See detailLocal vs. wide-area undervoltage load shedding in the presence of induction motor loads
Otomega, Bogdan; Van Cutsem, Thierry ULg

in Proceedings of the IEEE PES PowerTech 2009 conference (2009, July)

In the presence of induction motor loads, long-term voltage instability may end up in a sharp voltage decrease, which makes the tuning of undervoltage load shedding more delicate. This paper first ... [more ▼]

In the presence of induction motor loads, long-term voltage instability may end up in a sharp voltage decrease, which makes the tuning of undervoltage load shedding more delicate. This paper first investigates the ability of a purely distributed load shedding scheme, previously proposed by the authors, to cope with these situations. Owing to difficulties to reconcile dependability and security, an alternative wide-area protection is considered. The latter consists of generators sending overexcitation signals to the load shedding controllers in order to allow the latter to act faster. Detailed time simulations of a test system are reported. [less ▲]

Detailed reference viewed: 159 (8 ULg)
Full Text
Peer Reviewed
See detailSimplified time-domain simulation of detailed long-term dynamic models
Fabozzi, Davide ULg; Van Cutsem, Thierry ULg

in Proceedings of the 2009 IEEE PES General Meeting (2009, July)

Time-domain simulation of power system long-term dynamics involves the solution of large sparse systems of nonlinear stiff differential-algebraic equations. Simulation tools have traditionally focused on ... [more ▼]

Time-domain simulation of power system long-term dynamics involves the solution of large sparse systems of nonlinear stiff differential-algebraic equations. Simulation tools have traditionally focused on the accuracy of the solution and, in spite of many algorithmic improvements, time simulations still require a significant computational effort. In some applications, however, it is sufficient to have an approximate system response of the detailed model. The paper revisits the merits of the Backward Euler method and proposes a strategy to control its step size, with the objective of filtering out fast stable oscillations and focusing on the aperiodic behaviour of the system. The proposed method is compared to detailed simulation as well as to the quasi-steadystate approximation. Illustrative examples are given on a small but representative system, subject to long-term voltage instability. [less ▲]

Detailed reference viewed: 298 (39 ULg)
Full Text
Peer Reviewed
See detailA Framework for the Simultaneous Clearing of Multiple Markets within a Common Transmission System
Marinakis, Adamantios ULg; Rosehart, William; Van Cutsem, Thierry ULg

in Proceedings of the 2009 IEEE PES Power Tech conference (2009, July)

The possibility for market participants to place their bids in all the markets of an interconnection irrespective of where they are physically connected is investigated in this paper. A mechanism is ... [more ▼]

The possibility for market participants to place their bids in all the markets of an interconnection irrespective of where they are physically connected is investigated in this paper. A mechanism is proposed for managing the resulting congestion. It consists in iteratively sharing the transmission line capacities between the different market operators based each time on their present schedules. The algorithm is applied on a small test system. The results are assessed in terms of their property of being Nash equilibria and of their distance of the set of Pareto optimal operating points. [less ▲]

Detailed reference viewed: 56 (13 ULg)
Full Text
Peer Reviewed
See detailSecurity Assessment by Multiple Transmission System Operators Exchanging Sensitivity and Tie-Line Power Flow Information
Fabozzi, Davide ULg; Glavic, Mevludin; Wehenkel, Louis ULg et al

in Proceedings of the 2009 IEEE PES Power Tech conference (2009, July)

This paper considers a procedure for multi-area static security assessment of large interconnected power systems operated by a team of Transmission System Operators (TSOs). In this procedure, each TSO ... [more ▼]

This paper considers a procedure for multi-area static security assessment of large interconnected power systems operated by a team of Transmission System Operators (TSOs). In this procedure, each TSO provides the other TSOs with his own equivalent model as well as the detailed effects of contingencies in his control area on all tie-line flows. The paper deals with the implementation of sensitivity-based equivalents suitable for static security assessment. Accuracy with respect to the unreduced model and computational efficiency are considered in evaluating the proposed approach. The relevance of the procedure in the context of recent UCTE operational security policy recommendations is also stressed. The procedure has been implemented in an AC power flow program and tested on a three-area variant of the IEEE 118-bus test system. [less ▲]

Detailed reference viewed: 115 (23 ULg)
Full Text
Peer Reviewed
See detailApoptosis characterizes immunological failure of HIV infected patients
Mhawej, Marie-José; Brunet-Francois, Cécile; Fonteneau, Raphaël ULg et al

in Control Engineering Practice (2009), 17(7), 798-804

This paper studies the influence of apoptosis in the dynamics of the HIV infection. A new modeling of the healthy CD4+ T-cells activation-induced apoptosis is used. The parameters of this model are ... [more ▼]

This paper studies the influence of apoptosis in the dynamics of the HIV infection. A new modeling of the healthy CD4+ T-cells activation-induced apoptosis is used. The parameters of this model are identified by using clinical data generated by monitoring patients starting Highly Active Anti-Retroviral Therapy (HAART). The sampling of blood tests is performed to satisfy the constraints of dynamical system parameter identification. The apoptosis parameter, which is inferred from clinical data, is then shown to play a key role in the early diagnosis of immunological failure. [less ▲]

Detailed reference viewed: 171 (19 ULg)
Full Text
Peer Reviewed
See detailDevelopment and use of equation based simulation tools to support audit of commercial buildings
Bertagnolio, Stéphane ULg; Lebrun, Jean ULg; Andre, Philippe ULg

in Proceedings of the eleventh International IBPSA Conference, Glasgow, UK (2009, July)

A series of new simulation tools are being developed to help the building energy auditor in establishing his diagnosis (including benchmarking and detailed analysis of actual energy consumption) and in ... [more ▼]

A series of new simulation tools are being developed to help the building energy auditor in establishing his diagnosis (including benchmarking and detailed analysis of actual energy consumption) and in evaluating the selected Energy Conservation Opportunities (ECOs). The Building-HVAC System global models presented here include simplified models of building zones and of HVAC equipment. Only a limited number of easily identifiable parameters is required. The simplicity of the models and the use of an equation solver to run the simulation ensure good robustness and full transparency. The development, the implementation and the use of these models are discussed in the present paper. Focus is also given to the calibration of the tools to the monthly utility bills. [less ▲]

Detailed reference viewed: 67 (18 ULg)
Full Text
Peer Reviewed
See detailThe use of acidimetric titration as a novel approach to study particulate trace
Petit, Jérôme; Bouezmarni, Mohamed ULg; Roevros, Nathalie et al

in Applied Geochemistry (2009), 24(2009), 1875-1888

The study of trace metal speciation has benefited from a great deal of interest leading to the development and the diversification of sequential extraction schemes (SES), which triggered the need for ... [more ▼]

The study of trace metal speciation has benefited from a great deal of interest leading to the development and the diversification of sequential extraction schemes (SES), which triggered the need for harmonization by the standard, measurements and testing programme (SM & T). However, some uncertainties still persist in the application of the harmonized 3-step protocol, because of the difficulty in conceptualizing a technique that can be applied to environmental samples irrespective of their nature. The alternative method proposed in this study is based on the solubility of the sample components progressively dissolved during the course of an acidimetric titration by 1 mol L 1 HCl. The major HCl-reactive mineralogical components are identified using mass balance calculation of H+ consumed by their dissolution together with the amount of major elements released into solution. The speciation of minor and trace elements is investigated by comparing their titrations to those of the major elements. This approach is much simpler than SES because it uses simple non-selective H+ at room temperature instead of a complex experimental design of so-called specific reagents. The different mineral components of the solid are no longer operationally defined and the problem of selectivity is irrelevant to the titration approach. The method was applied to several sediment samples from the Scheldt estuary and the particulate phase was further examined by Scanning Electron Microprobe and X-ray Diffraction techniques. The nearly complete consumption of H+ in the suspension is balanced by the total dissolution of carbonates and Fe-oxyhydroxides. In contrast to the speciation inferred from the Tessier SES, the acidimetric titration has demonstrated that the carbonate phase does not significantly contain trace metals with the exceptions of 40% of the Mn and 30% of the Co. In contrast, the Fe-oxyhydroxides seem to play a major role and account for 70% of Pb and 20% of Cr, in addition to 60% of P and additional amounts of 20% Co and 40% Mn. 70% of the Cu also occur in the oxyhydroxide phase, more likely coprecipitated with gibbsite. 90% of the Cd and 85% of Zn can be attributed to the Acid Volatile Sulfide (AVS) phase as evidenced from S titration. The acidimetric titration method not only provides information on the speciation of trace metals but also allows the quantification of their reactivity and mobility, if one considers that the titration roughly mimics pH changes that may occur as a result of chemical disequilibrium in the environment. The results demonstrate the potential of the acidimetric titration as an alternative to SES protocols in geochemical and environmental regulation studies. This method is applicable to a wide variety of environmental materials with little or minor adjustments. [less ▲]

Detailed reference viewed: 247 (17 ULg)
Full Text
See detailAimer une ville comme on aime une femme
Purnelle, Gérald ULg

in Culture, le magazine culturel de l'Université de Liège (2009)

Detailed reference viewed: 69 (10 ULg)
Full Text
See detailLe roman en vers : genre moderne !
Purnelle, Gérald ULg

in Culture, le magazine culturel de l'Université de Liège (2009)

Detailed reference viewed: 63 (10 ULg)
Full Text
Peer Reviewed
See detailEntre deux, Poèmes déplacés
Pagnoulle, Christine ULg

in Journal des Poètes (2009), (2), 3-4

This file, which includes six poems and their translation, introduces poets whose allegiances are divided between at least two languages.

Detailed reference viewed: 71 (15 ULg)
Full Text
Peer Reviewed
See detailBaseline inflammation is not predictive of periprocedural troponin elevation after elective percutaneous coronary intervention.
Gach, Olivier ULg; Louis, Olivier ULg; Chapelle, Jean-Paul ULg et al

in Heart & Vessels (2009), 24(4), 267-70

High-sensitivity C-reactive protein predicts future cardiovascular events in both healthy individuals and patients with unstable and stable coronary syndromes. Few data are available about the incidence ... [more ▼]

High-sensitivity C-reactive protein predicts future cardiovascular events in both healthy individuals and patients with unstable and stable coronary syndromes. Few data are available about the incidence and the relation to inflammation of troponin elevation following percutaneous coronary intervention (PCI), a potential predictor of longterm outcome. We sought to confirm the impact of embolization on long-term outcome and evaluate the ability of baseline inflammation to predict troponin elevation induced by PCI. We prospectively analyzed 200 patients treated by PCI for stable or Braunwald IIA class unstable angina. The patients were recruited between January 1997 and May 1999, and the population was followed during a mean follow-up of 32 months. Major adverse cardiac events (MACEs) were defined as the occurrence of death, myocardial infarction or recurrent angina requiring repeat PCI, or coronary artery bypass grafting. During the follow-up period, 58 MACEs were observed. By multivariate analysis, independent predictors for the occurrence of MACEs were unstable angina and troponin I level after PCI (P < 0.0001 for both). No correlation was found between baseline inflammation and significant troponin I elevation post PCI and by multivariate analysis, no biological variable was a predictor of troponin I elevation post PCI. Baseline inflammation cannot predict onset of minor myonecrosis damage (expressed by troponin elevation) induced by PCI, a significant predictor of long-term outcome in this setting. [less ▲]

Detailed reference viewed: 34 (8 ULg)
Full Text
Peer Reviewed
See detailPurely Flavored Leptogenesis
Aristizabal Sierra, Diego ULg; Munoz, Luis Alfredo; Enrico, Nardi

in Physical Review D (2009), 80

We study a model for leptogenesis in which the total CP asymmetries in the decays and scatterings involving the SU(2) singlet seesaw neutrinos Nα vanish (ϵNα=0). Leptogenesis is possible due to ... [more ▼]

We study a model for leptogenesis in which the total CP asymmetries in the decays and scatterings involving the SU(2) singlet seesaw neutrinos Nα vanish (ϵNα=0). Leptogenesis is possible due to nonvanishing CP violating lepton flavor asymmetries, realizing a situation in which the baryon asymmetry is due exclusively to flavor effects. We study the production of a net lepton asymmetry by solving the Boltzmann equations specific to this model, and we show that successful leptogenesis can be obtained at a scale as low as the TeV. We also discuss constraints on the model parameter space arising from current experimental upper limits on lepton flavor violating decays. [less ▲]

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
See detailLiver transplantation from controlled donation after cardiac death (DCD) donors: a single center experience
Detry, Olivier ULg; Veys, Caroline; Seydel, Benoît ULg et al

in Liver Transplantation (2009, July), 15(7), 180-181

Detailed reference viewed: 92 (14 ULg)
Full Text
Peer Reviewed
See detailSpatial distribution of accumulation in the Adélie Land - Comparison of the Antarctic GLACIOCLIM-SAMBA observation data with remote sensing techniques and high-resolution climate models
Agosta, Cécile ULg; Genthon, Christophe; Favier, Vincent et al

Conference (2009, July)

The Surface Mass Balance (SMB) of Antarctica is typically much larger within the first 200 km from the coast than further inland. This is also likely where much of the SMB change is expected due to ... [more ▼]

The Surface Mass Balance (SMB) of Antarctica is typically much larger within the first 200 km from the coast than further inland. This is also likely where much of the SMB change is expected due to climate warming. That is why since 2004 the GLACIOCLIM- SAMBA French observatory monitors the SMB in this region with spatial scales resolving those of climate models. A stakes line made of 91 stakes was deployed along a 150 km transect from the coast of Adélie Land towards Dome C on the plateau. This transect is surveyed each year and 3 complete records are now available. We first compare recent SMB measurements with older reports from the 1972-1992 period. We show that a significant fraction of the observed kilometer-scale spatial variability is stationary with time. Moreover the large spatial and inter-annual variabilities of recent measurements are consistent with the historical ones. The lateral spatial significance of the transect is then evaluated using the background remote-sensing- based model of Arthern et al. (2006). Finally, results from 3 high-resolution climate models are presented and compared with the field reports: the global atmosphere-surface climate model LMDZ4 zoomed to reach a 35 km resolution over Antarctica, the regional atmospheric climate model MAR developed for polar regions (20 km resolution) and the ECMWF analysis (50 km resolution). We show large differences between the 3 models, which don’t have the same ability to reproduce the meso-scale characteristics of the distribution of the observed SMB in the critical coast-to-plateau area. [less ▲]

Detailed reference viewed: 17 (1 ULg)
Full Text
See detailDeuxième campagne de mesure des odeurs sur le site de traitement des déchets de Habay Estimation des nuisances olfactives
Nicolas, Jacques ULg; Waczek, Cédric; Delva, Julien et al

Report (2009)

The study is conducted in the frame of a programme of monitoring of all landfill sites in Wallonia. The "odour" part is assigned to ULg. The present report concerns more particularly a second campaign on ... [more ▼]

The study is conducted in the frame of a programme of monitoring of all landfill sites in Wallonia. The "odour" part is assigned to ULg. The present report concerns more particularly a second campaign on the site of Habay, which is more than a simple landfill area, as it includes also other waste treatment facilities, such as composting and biodrying. Besides the usual field inspection technique, the research group has applied the electronic nose methodology to monitor the odour in the vicinity of the sources and a survey in the surroundings to try to validate the different results. [less ▲]

Detailed reference viewed: 57 (1 ULg)
Full Text
Peer Reviewed
See detail3D MEDIA: A Unique Audio and Video R&D Project Spanning Wallonia
Verly, Jacques ULg; Meessen, Jérôme; Michel, Benoît

in ERCIM News (2009), (78), 42-43

Detailed reference viewed: 12 (0 ULg)