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See detailSatellite Formation Control Using Continuous Adaptive Sliding Mode Controller
Cho, Hancheol ULg; Kerschen, Gaëtan ULg

Conference (2016, September)

The focus of this study is on the development of a robust controller with a simple gain adaptation for satellite formation control. The complete nonlinear dynamics of the motion of the follower satellite ... [more ▼]

The focus of this study is on the development of a robust controller with a simple gain adaptation for satellite formation control. The complete nonlinear dynamics of the motion of the follower satellite relative to the leader satellite is considered and the rigorous proof for the stability of the controlled formation system is given in the presence of unknown external disturbances and unknown mass of the follower satellite. Although the controller design is based on the concept of sliding mode control, the proposed control strategy is free from chattering and guarantees a finite-time convergence of the controlled system to the target area. Furthermore, a simple adaptive law to automatically update the control gain is suggested that does not require a priori knowledge of the uncertainties of the system. In addition, to guarantee the robustness from the beginning and to improve the transient performance, a new sliding surface is also constructed. Numerical simulations are carried out to demonstrate the effectiveness of the proposed adaptive controller to maintain a desired formation configuration by compensating for the initial offset errors and external disturbance effects including gravitational perturbations and atmospheric drag. [less ▲]

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See detailA combined transmission spectrum of the Earth-sized exoplanets TRAPPIST-1 b and c
de Wit, Julien; Wakeford, Hannah R.; Gillon, Michaël ULg et al

in Nature (2016), 537

Three Earth-sized exoplanets were recently discovered close to the habitable zone of the nearby ultracool dwarf star TRAPPIST-1 (ref. 3). The nature of these planets has yet to be determined, as their ... [more ▼]

Three Earth-sized exoplanets were recently discovered close to the habitable zone of the nearby ultracool dwarf star TRAPPIST-1 (ref. 3). The nature of these planets has yet to be determined, as their masses remain unmeasured and no observational constraint is available for the planetary population surrounding ultracool dwarfs, of which the TRAPPIST-1 planets are the first transiting example. Theoretical predictions span the entire atmospheric range, from depleted to extended hydrogen-dominated atmospheres. Here we report observations of the combined transmission spectrum of the two inner planets during their simultaneous transits on 4 May 2016. The lack of features in the combined spectrum rules out cloud-free hydrogen-dominated atmospheres for each planet at ≥10σ levels; TRAPPIST-1 b and c are therefore unlikely to have an extended gas envelope as they occupy a region of parameter space in which high-altitude cloud/haze formation is not expected to be significant for hydrogen-dominated atmospheres. Many denser atmospheres remain consistent with the featureless transmission spectrum—from a cloud-free water-vapour atmosphere to a Venus-like one. [less ▲]

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See detailUse of NIR hyperspectral imaging to detect and quantify nodules on root system of associated crops
Eylenbosch, Damien ULg; Pierreux, Jérome ULg; Fernández Pierna, Juan Antonio et al

in ESA 14 -Growing landscape - Cultivating innovative agricultural systems (2016, September)

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See detailHeart Team Liege - Session Video Link
PIERARD, Luc ULg; vahanian, Alec; LANCELLOTTI, Patrizio ULg et al

Conference (2016, September)

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See detailComment j'explore... une dysmorphose dento-maxillo-faciale.
Urbain, Valérie; GILON, Yves ULg; BRUWIER, Annick ULg et al

in Revue Médicale de Liège (2016), 71(9), 394-399

Dento-maxillofacial dysmorphoses represent a considerable area of maxillofacial surgery. Their incidence has constantly been on the rise since the beginning of the century. This can be explained by ... [more ▼]

Dento-maxillofacial dysmorphoses represent a considerable area of maxillofacial surgery. Their incidence has constantly been on the rise since the beginning of the century. This can be explained by variations in the food and society habits.We will first discuss the various causes (congenital and environnemental) and the pathophysiology of these disorders. Then, we will separate them according to the skeletal and Angle’s classifications. We will examine the predictive criteria of these dysmorphoses from the youngest age and consider their clinical and cephalometrical diagnosis We will envisage their functional and aesthetic consequences and expose the preventive options. Finally, we will describe the orthodontic and surgical treatment available today and conclude that surgery remains the gold standard by restoring the conventional axis. [less ▲]

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See detailMethodik zur schnellen Bewertung von Syntheserouten auf Basis von Exergiebilanzen
Frenzel, Philipp; Pfennig, Andreas ULg

in Chemie Ingenieur Technik (2016), 88(9), 1381

Heutige chemische Produkte basieren fast ausschließlich auf erdölbasierten Rohstoffen. Aufgrund weltweiter Bemühungen, die Abhängigkeit von fossilen Rohstoffen zu reduzieren, wird in den letzten Jahren ... [more ▼]

Heutige chemische Produkte basieren fast ausschließlich auf erdölbasierten Rohstoffen. Aufgrund weltweiter Bemühungen, die Abhängigkeit von fossilen Rohstoffen zu reduzieren, wird in den letzten Jahren verstärkt die Nutzung alternativer Kohlenstoffquellen wie Biomasse oder CO2 erforscht. Die alternativen Kohlenstoffquellen unterscheiden sich hinsichtlich ihrer Zusammensetzung und Stoffeigenschaften teilweise deutlich von fossilen Rohstoffen. Aus diesem Grund müssen Syntheserouten und darauf aufbauende Prozesse neu entwickelt werden. Da zum einen sehr viele Syntheserouten prinzipiell denkbar sind und zum anderen die Entwicklung der entsprechenden Prozesse aufwendig ist, wird eine Möglichkeit benötigt, begrenzte Entwicklungsressourcen sinnvoll zu steuern. Dazu sollte bereits in einem frühen Entwicklungsstadium ein quantitativer Vergleich der Syntheserouten erfolgen, um diejenigen zu identifizieren, die das größte wirtschaftliche Potential versprechen. In diesem Vortrag wird eine Methodik vorgestellt, um eine schnelle erste, auf Exergie basierte Bewertung des wirtschaftlichen Potentials einer Syntheseroute bereits in einem frühen Entwicklungsstadium durchzuführen, in dem nur wenige Informationen vorliegen. Die Idee der Methodik ist, Syntheserouten in standardisierten Prozessen abzubilden, wodurch eine automatisierte Auswertung und somit ein schnelles Screening möglich wird. Die standardisierten Prozesse umfassen sowohl den Einfluss der Reaktion durch Abbildung der Reaktionsbedingungen, Stöchiometrie, Umsatz und Selektivität als auch die Auswirkungen der Trennaufgabe. Ebenso berücksichtigt wird die Rückführung von Lösungsmitteln und ggf. nicht umgesetzten Edukten. Als zentrale Bewertungsgröße zur Abschätzung des wirtschaftlichen Potentials wird eine Kombination aus Exergie- und Rohstoffeinsatz herangezogen. Der Vorteil von Exergiebilanzen gegenüber Energiebilanzen ist, dass die Produktion von Entropie berücksichtigt wird und so die Auswirkungen einzelner Prozessschritte untersucht und zwischen verschiedenen Energieformen unterschieden werden kann. Durch Berechnung der Exergieverluste, also der Verluste von Exergie aufgrund von Entropieerzeugung in den Prozessen, ergibt sich ein quantitativer Vergleich verschiedener Syntheserouten. [less ▲]

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See detailEvaluation of chemical composition of 6 available by-products in the North of Morocco
El Otmani, Samira ULg; Ayadi, Mohamed; Hornick, Jean-Luc ULg et al

in Book of Abstracts of the 12th International Conference on Goats (2016, September)

In the northern region of Morocco, goat breeding is the dominant activity of farmers. This livestock plays a major economic role in the contribution of more than 70% of household income. His diet is based ... [more ▼]

In the northern region of Morocco, goat breeding is the dominant activity of farmers. This livestock plays a major economic role in the contribution of more than 70% of household income. His diet is based essentially on forest rangelands characterized by a variable feed offer. Therefore, it is necessary to diversify and improve its feed calendar to reduce overgrazing and increase livestock productivity. This work aims to characterize the chemical composition of agricultural by-products to be introduced in the diet of goat herd. The studied by-products was residues of watermelon, melon, zucchini, tomato, sunflower and peanut. These samples were collected in the different places in the region of the north of Morocco. In the laboratory, they were dried in oven at 60°C and subsequently ground and sieved to 1 mm diameter. The studied composition parameters were dry matter, ash, total nitrogen and fat. The chemical composition of these samples was determined by the methods of AOAC (1997). The means and the standard error of means were calculated using SAS software. From results, dry matter of by-products varies from 16.4% in watermelon residues and 96.7% in sunflower residues. The sunflower residues has a low mineral content of 3% while the melon residue contains 26.5% of mineral matter. The nitrogenous matter ranges from 2.6% in sunflower residue to 19.5% in watermelon residues. The highest fat content was recorded in melon residues (5.1%). Sunflower residue is lower in fat (1.4%). In conclusion, sunflower and peanut residues drier than the other by-products and contain less mineral matter, fat and nitrogenous matter. These by-products represent a free feed that can take their place in feed calendar in the northern region of Morocco for the goat population. However, to introduce them in the diet, it is necessary to evaluate their nutritional values. [less ▲]

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See detailUNESCO, Cultural Industries and the International Development Agenda: Between Modest Recognition and Reluctance
Vlassis, Antonios ULg

in Stupples, Polly; Teaiwa, Katerina (Eds.) Contemporary perspectives on Art and International Development (2016)

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See detailContingence et nécessité chez Hegel et Spinoza
Lejeune, Guillaume ULg

in Studia Hegeliana (2016)

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See detailL’administration Obama, a t-elle (vraiment) navigué à vue sur la scène mondiale ?
Santander, Sébastian ULg

in Recherches internationales (2016), 106

Dès son arrivée au pouvoir, Obama a pris le soin de tenir un discours de rupture avec son prédécesseur dont l’action interventionniste et belliqueuse avait terni l’image des ÉU dans le monde. Il a sous ... [more ▼]

Dès son arrivée au pouvoir, Obama a pris le soin de tenir un discours de rupture avec son prédécesseur dont l’action interventionniste et belliqueuse avait terni l’image des ÉU dans le monde. Il a sous-entendu qu’il ne se laisserait pas enfermer dans des cadres idéologiques et qu’il privilégierait une approche « pragmatique » et « souple », et fait savoir qu’il n’engagerait plus les ÉU dans des opérations militaires de grande envergure. Ce discours d’une approche au cas par cas combiné à la politique du retrait militaire d’Irak et d’Afghanistan, et au fait que Obama a parfois été amené à adopter une attitude réactive pour répondre aux soubresauts de l’actualité internationale ont alimenté la perception dominante selon laquelle cette administration se désintéressait et se désengageait du monde, et déployait une politique étrangère marquée par l’indécision, l’improvisation et l’absence de vision à long terme. On ne peut omettre que cette administration a parfois du adapter et ajuster sa politique en fonction des événements internationaux. Faut-il pour autant conclure que sous Obama la première puissance mondiale a navigué à vue sur la scène internationale ? [less ▲]

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See detailGay adoptive families: between stressors and losses. 2 contrasted cases
Messina, Roberta ULg; D'Amore, Salvatore ULg

Conference (2016, September)

Gay adoptive families are more and more present in the European context (currently the full joint adoption by same sex couples is granted in 9 European countries and 4 countries permit the step-child ... [more ▼]

Gay adoptive families are more and more present in the European context (currently the full joint adoption by same sex couples is granted in 9 European countries and 4 countries permit the step-child adoption). Despite the numerous studies on lesbian and gay parent- headed families, the current literature that has focused specifically on gay adoptive parent families remains rather limited. This research has the aim of increase the scientific knowledge on this new family form with the purpose to shed light on typical stressors experienced by parents and by children. The specificity of these families consists, among others, to be at the crossroads of two levels of complexity: being adoptive families and being LG families. Like all LG families, gay adoptive families have to face different stressors such as the lack of support by families of origin and social context, the need to hide their parenting project, the fear to not be considered parents "like the others" and the worry that their children are discriminated because of parents’ homosexuality. In addition to these stressors linked to the family structure, there is the challenge to adopt a child already marked by difficult life experiences and abandonment. The specificity of these families is the product of the difficulties encountered from the couples to became parents and of the experience of loss experienced by the child. The result of this whole meeting, is often found in parents’ strategies to face stressors and in the weight that the loss takes on for the child and in the relational dynamics of the family. Through two contrasting cases we will reflect on the possible adaptive strategies of parents and on the importance of integrating the child history in a new family story in which past, present and future come together and don’t know fractures. [less ▲]

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See detailConclusion
Veymiers, Richard ULg

Conference (2016, September)

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See detailCooperative spontaneous emission from indistinguishable atoms in arbitrary motional quantum states
Damanet, François ULg; Braun, Daniel; Martin, John ULg

in Physical Review A (2016), 94

We investigate superradiance and subradiance of indistinguishable atoms with quantized motional states, starting with an initial total state that factorizes over the internal and external degrees of ... [more ▼]

We investigate superradiance and subradiance of indistinguishable atoms with quantized motional states, starting with an initial total state that factorizes over the internal and external degrees of freedom of the atoms. Due to the permutational symmetry of the motional state, the cooperative spontaneous emission, governed by a recently derived master equation [F. Damanet et al., Phys. Rev. A 93, 022124 (2016)], depends only on two decay rates γ and γ0 and a single parameter dd describing the dipole-dipole shifts. We solve the dynamics exactly for N = 2 atoms, numerically for up to 30 atoms, and obtain the large-N limit by a mean-field approach. We find that there is a critical difference γ0 − γ that depends on N beyond which superradiance is lost. We show that exact nontrivial dark states (i.e., states other than the ground state with vanishing spontaneous emission) only exist for γ = γ0 and that those states (dark when γ = γ0) are subradiant when γ < γ0. [less ▲]

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See detailThe influence of England on the first English gardens in the Southern Low Countries and the Principality of Liege
De Harlez De Deulin, Nathalie ULg

in Garden History (2016), 44(Automn), 87-100

The English Garden appearead in the Low Countries quite late in the 18th century since the geometric model – mainly influenced by the French style diffused by the treatise of Dezallier d’Argenville – is ... [more ▼]

The English Garden appearead in the Low Countries quite late in the 18th century since the geometric model – mainly influenced by the French style diffused by the treatise of Dezallier d’Argenville – is still in fashion in the years 1760. Amongst the famous realizations of the time figure the Garden of Leeuwergem Castle (1762), the upper Garden of Freÿr Castle (c. 1775) or the Royal Park of Brussels (1786). The two following decades (1760-1780) correspond to the major development of the new irregular style in the Low Countries merely influenced by Picturesque Garden but also by Naturalistic style Garden discovered by members of the aristocracy travelling in Great Britain as well as some gardeners sent to England to be trained and to learn how to grow new exotic plants. This paper deals with the major designers and the most famous sleeping partners engaged in the program of creation of the first English gardens in the country, notably Prince Charles-Joseph de Ligne (Beloeil and Baudour), Duke Emmanuel de Croÿ (Hermitage), Count of Seneffe Joseph Depestre (Seneffe), Duke Emmanuel d’Hane Steenhuyse (Leeuwergem) and, first of all, Duke Albert de Saxe-Teschen and the Archduchess Marie Christine who asked Lancelot Brown a plan for the site near Brussels called the Fine Mountain (Schoonenberg). Brown has sent his project from Britain in July 1782. We have also taken interest in the many unknown owners who gathered important plants collection that are only described in travel diaries or mentioned in archives (inventories and other lists of purchase or supply) that have no longer survived. This article present some facets of the global research accomplished in the thesis (2015) focusing on the direct influence of the English design on the first irregular gardens in the Southern Low Countries. [less ▲]

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See detailJudiciarisation des systèmes politiques et sociaux. Recueil d'arrêts
Grandjean, Geoffrey ULg

Learning material (2016)

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See detailMeeting in Brackets - Devising Belgian Mental Health Policies through Inter-organisational Meetings
Thunus, Sophie ULg

Conference (2016, September)

Object: this paper analyses inter-organisational meetings held in response to a reform of the Belgian mental health care system. It proposes to shift the researcher’s attention from the instrumental ... [more ▼]

Object: this paper analyses inter-organisational meetings held in response to a reform of the Belgian mental health care system. It proposes to shift the researcher’s attention from the instrumental function attributed to meetings to the role they actually play in this reform. Aims: based on the observation that meetings frequently failed to reach their instrumental outcome, this paper first asks which other roles meetings might play and how. Second, it suggests that the concept of bracketing might be helpful in perceiving, describing and analysing the roles played by meetings. Methods: this paper relies on empirical material collected through semi-structured interviews, direct observation and documentary analyse. Excerpts from interviews and field notes of observation are used as a basis for analysing 4 specific meetings. These meetings have been selected according to their relevance to the research question of the role played by meetings and a set of criteria relating to the meeting type, participants, topic and context. Results: this paper demonstrates that, next to their instrumental function, meetings play at least three complementary roles, which are defined as expressive, representative and performative. It argues that these three roles of meetings are better understood by using the concept of bracketing in three ways: as a methodological, descriptive and analytical tool. [less ▲]

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See detailHome blood pressure in kidney transplant recipients (Ktr) - Validity of different schedules of self-monitoring
SAINT-REMY, Annie ULg; WEEKERS, Laurent ULg; BONVOISIN, Catherine ULg et al

in Journal of Hypertension (2016, September), 34(e supplement 2), 119

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