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Peer Reviewed
See detailAnalysis of Minimal In-Flight Oxygen Collection Cycle for Two Stage Launchers
Bizzarri, Didier; Heyen, Georges ULiege; Hendrick, Patrick et al

in 14th AIAA/AHI International Space Planes and Hypersonic Systems and Technologies Conference (2006, November)

Detailed reference viewed: 30 (2 ULiège)
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See detailAn analysis of mixed integer linear sets based on lattice point free convex sets
Andersen, Kent; Louveaux, Quentin ULiege; Weismantel, Robert

in Mathematics of Operations Research (2010), 35(1), 233-256

The set obtained by adding all cuts whose validity follows from a maximal lattice free polyhedron with max-facet-width at most w is called the w th split closure. We show the w th split closure is a ... [more ▼]

The set obtained by adding all cuts whose validity follows from a maximal lattice free polyhedron with max-facet-width at most w is called the w th split closure. We show the w th split closure is a polyhedron. This generalizes a previous result showing this to be true when w = 1. We also consider the design of finite cutting plane proofs for the validity of an inequality. Given a measure of “size” of a maximal lattice free polyhedron, a natural question is how large a size s of a maximal lattice free polyhedron is required to design a finite cutting plane proof for the validity of an inequality. We characterize s based on the faces of the linear relaxation of the mixed integer linear set. [less ▲]

Detailed reference viewed: 99 (17 ULiège)
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See detailAnalysis of models of redistribution of direct support to farm income in the European Union
Terrones Gavira, François ULiege; Dellanoy, Sylvain; Closset, Marie-France et al

in Vîntu, Vasile (Ed.) Proceedings of the 55th International Scientific Conference "100 years of Iasi higher education in agronomy" : book of abstracts (2012)

Detailed reference viewed: 61 (12 ULiège)
See detailAnalysis of mortality and morbidity data
Brichant, Jean-François ULiege

Conference (2010, January 08)

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See detailAnalysis of MRI stomach scans using differential equations
Frasso, Gianluca ULiege; Lambert, Philippe ULiege; Eilers, Paul H.C.

Poster (2014, September)

Differential equations (DE) are commonly used to describe dynamic systems evolving in one (e.g. time) or more dimensions (e.g. space and time). In real applications the parameters defining the theoretical ... [more ▼]

Differential equations (DE) are commonly used to describe dynamic systems evolving in one (e.g. time) or more dimensions (e.g. space and time). In real applications the parameters defining the theoretical model describing the phenomenon under consideration are often unknown and need to be estimated from the available measurements. This estimation task has been extensively discussed in the statistical literature and probably the most popular procedures are those relying on nonlinear least squares (Bielger et al, 1986). These approaches are computationally intensive and often poorly suited for statistical inference. An attractive alternative is represented by the penalized smoothing procedure introduced by Ramsay et al. (2007). This approach can be viewed as a generalization of the L-spline framework (see Welham et al., 2006 among others) where the flexibility of a high dimensional B-spline expansion of the state function is counterbalanced by a penalty term defining the (set of) differential equation(s) synthesizing the dynamics under investigation. The fidelity of the extracted signal to the hypothesized model is then tuned by a “DE-compliance” parameter to be extracted form the data too. This approach works reasonably well both with linear and nonlinear differential models but, in the latter case, due to the implicit link between the vector of unknown DE parameters and the spline coefficients, the computational burden tends to increase and the optimization of the compliance parameter can be demanding. To overcome these drawbacks we adopt the quasilinearized (QL) ODE-P-spline approach proposed by Frasso et al. (2014). The quasilinearization (Bellman and Kalaba, 1965) step greatly reduces the computational cost of the estimation procedure making the penalty term a second order polynomial function of the DE parameters. As motivating example we present the results of a QL-ODE-P-spline analysis of a set of MRI scans describing stomach contractions during digestion. For illustrative purposes we analyze the measurements related to a single slice of the stomach. Finally, we conclude with a discussion of the possible further extensions of the presented methodology. [less ▲]

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See detailAnalysis of Ocean in Situ Observations and Web - Based Visualization: From Individual Measurements to an Integrated View
Barth, Alexander ULiege; Watelet, Sylvain ULiege; Troupin, Charles et al

in Diviacco, Paolo; Leadbetter, Adam; Glaves, Helen (Eds.) Oceanographic and Marine Cross-Domain Data Management for Sustainable Development (2016)

The sparsity of observations poses a challenge common to various ocean disciplines. Even for physical parameters where the spatial and temporal coverage is higher, current observational networks ... [more ▼]

The sparsity of observations poses a challenge common to various ocean disciplines. Even for physical parameters where the spatial and temporal coverage is higher, current observational networks undersample a broad spectrum of scales. This situation is generally more severe for chemical and biological parameters because such sensors are less widely deployed. The present chapter describes the analysis tool DIVA (Data-Interpolating Variational Analysis) which is designed to generate gridded fields from in situ observations. DIVA has been applied to various physical (temperature and salinity), chemical (concentration of nitrate, nitrite and phosphate) and biological parameters (abundance of a species). The chapter also shows the technologies used to visualize the gridded fields. Visualization of analyses from in situ observations provide a unique set of challenges since the accuracy of the analysed field is not spatially uniform as it strongly depends on the location of the observations. In addition, an adequate treatment of the depth and time dimensions is essential. [less ▲]

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See detailAnalysis of ocean in situ observations and web-based visualization
Barth, Alexander ULiege; Watelet, Sylvain ULiege; Troupin, Charles ULiege et al

Conference (2016)

The sparsity of observations poses a challenge common to various ocean science disciplines. Even for physical parameters where the spatial and temporal coverage is higher, current observational networks ... [more ▼]

The sparsity of observations poses a challenge common to various ocean science disciplines. Even for physical parameters where the spatial and temporal coverage is higher, current observational networks undersample a broad spectrum of scales. The situation is generally more severe for chemical and biological parameters because related sensors are less widely deployed. The analysis tool DIVA (Data-Interpolating Variational Analysis) is designed to generate gridded fields from in situ observations. DIVA has been applied to various physical (temperature and salinity), chemical (concentration of nitrate, nitrite and phosphate) and biological parameters (abundance of a species) in the context of different European projects (SeaDataNet, EMODnet Chemistry and EMODnet Biology). We show the technologies used to visualize the gridded fields based on the Web Map Services standard. Visualization of analyses from in situ observations provides a unique set of challenges since the accuracy of the analysed field is not spatially uniform as it strongly depends on the observations location. In addition, an adequate handling of depth and time dimensions is essential. Beside visualizing the gridded fields, access is also given to the underlying observations. It is thus also possible to view more detailed information about the variability of the observations. The in situ observation visualization service allows one to display vertical profiles and time series and it is built upon OGC standards (the Web Feature Service and Web Processing Services) and following recommendation from the INSPIRE directive. [less ▲]

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Peer Reviewed
See detailAnalysis of Ocean In Situ Observations and Web-Based Visualization: From Individual Measurements to an Integrated View
Barth, Alexander ULiege; Watelet, Sylvain ULiege; Troupin, Charles ULiege et al

in Paolo, Diviacco; Leadbetter, Adam; Glaves, Helen (Eds.) Oceanographic and Marine Cross-Domain Data Management for Sustainable Development (2017)

Detailed reference viewed: 26 (1 ULiège)
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See detailAnalysis of on-pump and off-pump surgery in the Arterial Revascularization Trial.
Poullis, Michael; Kolh, Philippe ULiege

in European Journal of Cardio - Thoracic Surgery (2015), 47(6), 1065

Detailed reference viewed: 9 (0 ULiège)
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See detailAnalysis of open-loop control design and parallel computation for underactuated manipulators
Bastos, Guaraci Jr; Bruls, Olivier ULiege

in Acta Mechanica (2020), 231

Trajectory tracking problems for underactuated manipulators represent an actual research topic, which is sustained by the interest in a lighter and faster automatic class of mechanical systems, bringing ... [more ▼]

Trajectory tracking problems for underactuated manipulators represent an actual research topic, which is sustained by the interest in a lighter and faster automatic class of mechanical systems, bringing some benefits as lower energy consumption, higher productivity and a more convenient human–machine interaction. This work presents a feedforward design method, which is based on the inverse dynamics of underactuated manipulators. To achieve this aim, an optimal control problem is formulated based on a direct multiple shooting method and the mechanical model is formulated according to the nonlinear finite element approach. Based on the proposed formulation, a bounded solution of the inverse dynamics problem can be achieved. The main contributions of this work are: (1) the development of an alternative formulation for the trajectory tracking problem of underactuated manipulators; (2) a parallel computation method for the inverse dynamics of underactuated manipulators; (3) a comparison/validation with the direct transcription method and the stable inversion method. A planar underactuated manipulator with one passive joint is considered as an illustrative example, but the methodology is general and could be applied to more complex systems, e.g. with flexible bodies, with parallel kinematics and in 3D. [less ▲]

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See detailAnalysis of ordinal longitudinal data
Donneau, Anne-Françoise ULiege

Conference (2007, November 24)

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See detailAnalysis of P Cygni line profiles - Generalization of the nth order moment WN
Surdej, Jean ULiege

in Astronomy and Astrophysics (1985), 152

The generalization of the nth order moment W[SUB]n[/SUB] of a P Cygni line profile leads to a new approach of deriving the various physical quantities which characterize the phenomenon of mass-loss around ... [more ▼]

The generalization of the nth order moment W[SUB]n[/SUB] of a P Cygni line profile leads to a new approach of deriving the various physical quantities which characterize the phenomenon of mass-loss around stars, quasars, etc. Adopting realistic expressions for the velocity and opacity distributions the author presents and discusses the results of calculations of the moments W[SUB]n[/SUB] in two types of different diagrams: the "log (W[SUB]n[/SUB])-log(W[SUB]n[/SUB][SUP]0[/SUP])" and "log(W[SUB]n[/SUB])-log (W[SUB]0[/SUB])" diagrams. The physical representation of the parameters W[SUB]n[/SUB][SUP]0[/SUP] is then given and the author tests and generalizes the validity of some of the linear relations W[SUB]n[/SUB] â W[SUB]n[/SUB][SUP]0[/SUP] for the case of slowly expanding optically thin atmospheres. [less ▲]

Detailed reference viewed: 89 (1 ULiège)
Peer Reviewed
See detailAnalysis of parasitic effects in the performance of closed loop micromachined inertial sensors with higher order SD-Modulators
Mokhtari, M.; Kraft, Michael ULiege; Alavi, F.N. et al

in Proc. Micromechanics Europe (MME) (2002, October)

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See detailAnalysis of Passion Fruit Rinds (Passiflora edulis): Isoorientin Quantification by HPTLC and Evaluation of Antioxidant ( Radical Scavenging) Capacity
Zeraik, Maria Luiza; Yariwake, Janete; Wauters, Jean-Noël ULiege et al

in Quimica Nova (2012), 35(3), 541-545

The content of isoorientin in passion fruit rinds ( Passiflora edulis fo. flavicarpa O.Degener) was determined by HPTLC with densitometric analysis. The results revealed a higher amount of isoorientin in ... [more ▼]

The content of isoorientin in passion fruit rinds ( Passiflora edulis fo. flavicarpa O.Degener) was determined by HPTLC with densitometric analysis. The results revealed a higher amount of isoorientin in healthy rinds of Passiflora than in rinds with typical symptoms of PWV ( Passion fruit woodliness virus). the HPTLC data ,allied to assays of radical scavenging activity, suggest the potential of P. edulis rinds as a natural source of flavonoids or as a possible functional food. [less ▲]

Detailed reference viewed: 120 (6 ULiège)
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See detailAnalysis of Passive cooling and heating potential in Vietnam using Graphical Method and Typical Meteorological Year weather file
Nguyen, Anh Tuan ULiege; Reiter, Sigrid ULiege

in Proceedings of CISBAT 2011 (2011, September 15)

This paper studies the potential to improve thermal comfort in Vietnam thanks to passive strategies. First, a thermal comfort zone for the Vietnamese is proposed by using the PMV-PPD heat balance model of ... [more ▼]

This paper studies the potential to improve thermal comfort in Vietnam thanks to passive strategies. First, a thermal comfort zone for the Vietnamese is proposed by using the PMV-PPD heat balance model of Fanger and the effects of adaptive mechanism of the people living in tropical hot humid region. Then, the comfort zone is enlarged using the algorithms proposed by the authors to calculate the effects of the passive heating and cooling strategies. Typical Meteorological Year (TMY) weather data are used for graphically printing of hourly environmental parameters on the psychrometric chart and for climate analysis, subsequently. The limitation and the scope of this method are also specified. Results of this study show that in all climatic zones of Vietnam, natural ventilation is an efficient cooling solution, low-cost and easy to apply. Thermal comfort improvement of natural ventilation strategy varies with the climatic zones, increasing from 17.1% in Hanoi, 21% in Danang to 31.4% in Hochiminh city. Meanwhile, passive solar heating is not really effective since winter in Vietnam is usually not too cold and the capacity of the passive solar collector system is usually limited. Direct evaporative cooling also has a great cooling effect compared with that of natural ventilation, but significant humidity augmentation in the air in hot and humid conditions may be inappropriate. Seasonal analysis reveals that natural ventilation gives higher performance than other methods and is particularly effective in mild seasons. During 12 months in Hanoi, the analysis clearly shows significant contribution of natural ventilation in the period from April to October during which comfort period achieved might vary from 30% to 81%. The combination of all passive strategies considerably improves thermal comfort: 22.6%, 31.7% and 47.6% of total time in Hanoi, Danang and Hochiminh city, respectively. Finally, the findings of this study indicate that conventional heating and cooling methods are also needed during extreme weather conditions in summer and winter, especially in Hanoi. [less ▲]

Detailed reference viewed: 156 (18 ULiège)
See detailAnalysis of past an projkected future land use change and its impact on sediment fluxes in the Rwizi catchment
Twongyirwe, Ronald; Opio, Alfons; Van Rompaey, Anton et al

Conference (2018)

Detailed reference viewed: 21 (1 ULiège)
Peer Reviewed
See detailAnalysis of Pax6b function in pancreatic and enteroendocrine cells reveals both tissue-specific and common regulatory networks
Peers, Bernard ULiege

Conference (2018, October 29)

The transcription factor Pax6 plays a crucial role for the differentiation of the endocrine cells in the pancreas and the intestine. Indeed, while endocrine cells are still generated in pax6 mutants, the ... [more ▼]

The transcription factor Pax6 plays a crucial role for the differentiation of the endocrine cells in the pancreas and the intestine. Indeed, while endocrine cells are still generated in pax6 mutants, the proportion of the different endocrine cell types secreting distinct hormones is strongly affected in both the pancreas and the intestine of Pax6 mutants. To understand how Pax6 influence cell choice during cell differentiation, we analyzed the transcriptome of pancreatic and intestinal endocrine cells isolated from wild type as well as in pax6b-/- zebrafish embryos. These data show that enteroendocrine cells are closely related to the pancreatic endocrine cells and a large set of genes are regulated similarly in both tissues. Such data support the concept that the endocrine cells of the pancreas and of the intestine are phylogenetically related. Besides this study, I will present briefly the characterization of the transcriptome of pancreatic progenitors isolated from wild type zebrafish embryos. [less ▲]

Detailed reference viewed: 14 (0 ULiège)