Publications ORBi OA
Bookmark and Share    
Full Text
See detailRound table. Quaternary Prevention(P4) or first do not harm.
Jamoulle, Marc ULg; Ouvrard, Patrick; Widmer, Daniel et al

Conference (2017, September 07)

see pdf

Detailed reference viewed: 24 (0 ULg)
Full Text
See detailMagneto-optical investigation of superconducting hybrid structures
Brisbois, Jérémy ULg

Doctoral thesis (2017)

Detailed reference viewed: 41 (6 ULg)
Full Text
See detailFunctional diversity and mowing regime of flower strips as tools to support pollinators and to suppress weeds
Uyttenbroeck, Roel ULg

Doctoral thesis (2017)

Intensification of agriculture during past decades is one of the causes of biodiversity declines. Ecological intensification has been proposed as a more sustainable alternative of intensive agriculture ... [more ▼]

Intensification of agriculture during past decades is one of the causes of biodiversity declines. Ecological intensification has been proposed as a more sustainable alternative of intensive agriculture that should be able to fulfill worldwide demands of food, by optimizing ecosystem functions and services and reducing environmental impacts. One way to restore ecosystem functions and services in arable fields is creating flower strips in field margins. These flower strips enable wild plant communities to thrive and provide food and shelter to associated fauna. It is often suggested that increasing plant functional diversity could be a tool to optimize ecosystem functioning and ecosystem service delivery, and it could thus be a goal for the creation and management of flower strips. An example of ecosystem functioning studied in this manuscript, is the mutualistic interaction between plants and pollinators. To convince European farmers to implement flower strips, they are included in the subsidized Agri-Environment Schemes. However, there exists no clear appraisal of the pros and cons of flower strips for farmers. By systematically reviewing the literature for pros and cons, we found that most studies concerned agronomical and ecological processes related to flower strips, but few or no studies were dedicated to the social and economic aspects. Furthermore, pollination appears to be an important pro, and weed infestation a possible con, depending on flower strip creation and management. We focused on these two examples in the further study. We investigated (1) whether the increase of plant functional diversity can be used as tool to optimize flower strips for pollinators, (2) whether forb competition and adapting timing and frequency of mowing can be used as tools to limit weeds in flower strips, and (3) whether flower strips perform equally in supporting pollinators as the natural habitat for which they are thought to be a surrogate. To use functional diversity as a tool to optimize flower strips for pollinators, we first tested whether it is possible to create a flower strip with a desired functional diversity level. We sew experimental flower strips with increasing functional diversity, based on visual, morphological and phenological flower traits and surveyed the vegetation composition the first year after sowing. The sown gradient of functional diversity was present, but with lower absolute values due to unequal cover of sown species and due to the presence of spontaneous species. To test the effect on pollinator support, we monitored the plant-pollinator networks in the experimental strips during two years. In contrast to our expectations, pollinator species richness and evenness were not influenced by functional diversity, and increasing functional diversity even resulted in lower flower visitation rates. To investigate the effect of forb competition and timing and frequency of mowing on weed infestation, we created experimental flower strips either with grass and forb species in the seed mixture, either with only grass species. Three different mowing regimes were applied: summer mowing, autumn mowing and mowing both in summer and autumn. The cover of important weed, Cirsium arvense, was limited by adding forbs to the seed mixture and by mowing in summer or in summer and autumn. At last, by surveying plant-pollinator networks in perennial flower strips and natural hay meadows in the same landscape context, we observed that both the plant and the pollinator communities differed between the flower strips and the meadows. Perennial flower strips can thus be considered as a complementary habitat in the landscape and not a hay meadow surrogate. This study suggests that it is possible to manipulate the vegetation as well as infestation by certain weeds in flower strips by adapting the seed mixture and the mowing regime. However, to promote pollinators in flower strips, increasing plant functional diversity appears not to be the key, and the abundance of certain attractive plant species can be more important. Moreover our results suggest that pollinators perceived a lower redundancy of functional plant trait values when functional diversity was higher, as they had more separate feeding niches (less visited flower species in common). Our results also suggest that there could be a trade-off between the increase of functional trait diversity and the floral resource abundance per niche or functional trait combination. With the results of the tested flower strip creation and management methods and their effect on pollinator support and weed infestation, farmers and administrations can try to create and manage flower strips with the desired balance between pros and cons, and researchers can try to refine these methods and test the effects on other pros and cons. [less ▲]

Full Text
See detailL'abandon de sanctuaires et le transfert de cultes en Grèce antique
Palamidis, Alaya ULg

Doctoral thesis (2017)

Dans la Grèce antique, les sanctuaires anciens comme les sanctuaires nouvellement fondés étaient censés continuer à être fréquentés indéfiniment. Cependant, ce n’était pas le cas de tous les lieux de ... [more ▼]

Dans la Grèce antique, les sanctuaires anciens comme les sanctuaires nouvellement fondés étaient censés continuer à être fréquentés indéfiniment. Cependant, ce n’était pas le cas de tous les lieux de culte: certains pouvaient être abandonnés, de même que les divinités qui y étaient honorées, tandis que d’autres divinités continuaient à être honorées à un emplacement différent. Ce travail vise en premier lieu à analyser les sources littéraires, épigraphiques et surtout archéologiques qui nous renseignent sur des tels abandons de sanctuaires et transferts de cultes. L’étude de deux types de déplacements de population, les synécismes et les métécismes, au cours desquels de tels abandons et transferts sont documentés, permet par la suite de réfléchir notamment aux raisons qui expliquent l’abandon de certains sanctuaires plutôt que d’autres. L’analyse des sources disponibles suggère que ni les abandons de sanctuaires, ni les transferts de culte n’étaient considérés comme la transgression d’une norme tacite ou orale et que ces phénomènes sont beaucoup plus courants que ce qui est généralement supposé. [less ▲]

Detailed reference viewed: 23 (1 ULg)
Full Text
Peer Reviewed
See detailAnalysis of definitions of General Practice/Family Medicine and Primary Health Care
Jamoulle, Marc ULg; Resnick, Melissa; Ittoo, Ashwin ULg et al

in British Journal of General Practice (2017)

Abstract Background There are numerous definitions of General Practice and Family Medicine (GP/FM) and Primary Health Care (PHC), but the distinction between the two concepts is unclear. Aim To conduct a ... [more ▼]

Abstract Background There are numerous definitions of General Practice and Family Medicine (GP/FM) and Primary Health Care (PHC), but the distinction between the two concepts is unclear. Aim To conduct a terminological analysis of a set of definitions of GP/FM and of PHC, to clarify what binds and what distinguishes these two concepts. Design The terms of 20 definitions were collected in two bags of words (one for GP/FM and one for PHC terms). A terminological analysis of these two bags of words was performed to prioritize the terms and analyze their world of reference. Methods The two collected bags of words were extracted with Vocabgrabber®, configured in two term butts using Wordle®, and further explored for similarities using Tropes®. The prioritized terms were analyzed using the Aristotelian approach to categorization of things. Results Although continuity of care (with person-centered approach and shared decision making) is the central issue of the two sets, the two sets of definitions differ greatly in content. The prioritized terms specific to GP/FM (community, medicine, responsibility, individual, problem, needs, ...) are different from prioritized terms specific to PHC (home, team, promotion, collaborator, engagement, neighborhood, medical center…). Conclusion Terminological analysis of the definitions for GP/FM and PHC shows two entities which are overlapping but distinct, necessitating a different taxonomic approach and different bibliographic search strategies. [less ▲]

Detailed reference viewed: 242 (4 ULg)
Full Text
Peer Reviewed
See detailSynthesis, characterization, and durability study of Pt-Co hollow nanoparticles deposited on carbon xerogel electrocatalysts for Proton Exchange Membrane Fuel Cells (PEMFC)
Zubiaur, Anthony ULg; Asset, Tristan ULg; Olu, Pierre-Yves et al

Poster (2017, September)

Proton exchange membrane fuel cell (PEMFC) catalysts are generally made of carbon black (CB)supported platinum-based nanoparticles. However, the properties of CBs, as described by RodríguezReinoso [1 ... [more ▼]

Proton exchange membrane fuel cell (PEMFC) catalysts are generally made of carbon black (CB)supported platinum-based nanoparticles. However, the properties of CBs, as described by RodríguezReinoso [1], are not optimal for electrocatalysis. A possible solution to the drawbacks of CBs is the use of synthetic nanostructured materials with a controllable and reproducible texture and with a pure, known and constant chemical composition; carbon xerogels (CX) exhibit such properties [2]. Recently, various highly dispersed CX-supported Pt nanoparticles catalysts (Pt/CX) have been synthesized via several methods, such as the strong electrostatic adsorption (SEA) [3] or the charge-enhanced dry impregnation (CEDI) [4]. However, the decrease of the Pt mass contained in the PEMFC electrodes, in particular at the cathode where the oxygen reduction reaction (ORR) is processed, remains a major challenge. Improving the ORR mass activity is currently best achieved by alloying Pt with 3d-transition metal atoms such as cobalt (Co). These alloys perform better than the ORR because the substitution of some Pt atoms by 3d-metal atoms with smaller radius leads to a modified Pt electronic structure [5]. The synthesis and durability of Pt-Co hollow particles/CX (Fig. 1) is currently being studied in our groups. The results indicate that the specific and mass activity of the bimetallic hollow particles dispersed on CX is ca. 10 times higher than that of pure Pt/CB. The first durability results show good stability of the hollow particles structure. Performances and accelerated stress tests (ASTs) in PEMFCs were finally performed. [less ▲]

Detailed reference viewed: 74 (2 ULg)
Full Text
Peer Reviewed
See detailIs a Memoryless Motion Detection Truly Relevant for Background Generation with LaBGen?
Laugraud, Benjamin ULg; Van Droogenbroeck, Marc ULg

in Advanced Concepts for Intelligent Vision Systems (2017, September)

The stationary background generation problem consists in generating a unique image representing the stationary background of a given video sequence. The LaBGen background generation method combines a ... [more ▼]

The stationary background generation problem consists in generating a unique image representing the stationary background of a given video sequence. The LaBGen background generation method combines a pixel-wise median filter and a patch selection mechanism based on a motion detection performed by a background subtraction algorithm. In our previous works related to LaBGen, we have shown that, surprisingly, the frame difference algorithm provides the most effective motion detection on average. Compared to other background subtraction algorithms, it detects motion between two frames without relying on additional past frames, and is therefore memoryless. In this paper, we experimentally check whether the memoryless property is truly relevant for LaBGen, and whether the effective motion detection provided by the frame difference is not an isolated case. For this purpose, we introduce LaBGen-OF, a variant of LaBGen leverages memoryless dense optical flow algorithms for motion detection. Our experiments show that using a memoryless motion detector is an adequate choice for our background generation framework, and that LaBGen-OF outperforms LaBGen on the SBMnet dataset. We further provide an open-source C++ implementation of both methods at http://www.telecom.ulg.ac.be/labgen. [less ▲]

Detailed reference viewed: 101 (6 ULg)
Full Text
Peer Reviewed
See detailA First Look at the Prevalence and Persistence of Middleboxes in the Wild
Edeline, Korian ULg; Donnet, Benoît ULg

in International Teletraffic Congress (2017, September)

Recent years have seen an uprise in the development of middleboxes functionalities (CGNATs, proxies, accelerators, etc), participating so in the ossification of the Internet. In parallel, various ... [more ▼]

Recent years have seen an uprise in the development of middleboxes functionalities (CGNATs, proxies, accelerators, etc), participating so in the ossification of the Internet. In parallel, various solutions have been developed to detect or circumvent unwanted middleboxes interferences such as UDP-based middlebox-proof transports (Google's QUIC, PLUS), middlebox-proof extensions to TCP (HICCUPS, TCPcrypt), and middlebox traversal mechanisms (STUN, ICE, PLUS). All those solutions make the assumption of ubiquitous middleboxes. However, a view of their actual deployment in the wild, in IPv4 wired networks, is missing. In particular, knowing how autonomous systems (ASes) deploy middleboxes in terms of prevalence and persistence would provide additional relevant information to Internet topology models. In this paper, we aim at filling this gap. Based on a large-scale measurement campaign, we highlight different characteristics of middlebox deployment within ASes to elicit middleboxes profiles. [less ▲]

Detailed reference viewed: 51 (18 ULg)
Full Text
Peer Reviewed
See detailVisco-plastic Chaboche model for nickel-based alloys under anisothermal cyclic loading
Morch, Hélène ULg; Duchene, Laurent ULg; Habraken, Anne ULg

in Proceedings of the XIV International Conference on Computational Plasticity (2017, September)

The mechanical behavior of visco-plastic materials such as nickel-based alloys is highly dependent on temperature. Some characteristics such as viscosity, hardening, static recovery, dynamic recovery have ... [more ▼]

The mechanical behavior of visco-plastic materials such as nickel-based alloys is highly dependent on temperature. Some characteristics such as viscosity, hardening, static recovery, dynamic recovery have more or less influence on the overall behavior depending on the considered temperature. The unified constitutive model developed by Chaboche [1] is very efficient in representing this complexity as it is very adaptable and can contain many features. A basic Chaboche model contains a viscosity law and one or several hardening equations. Within these hardening equations, it is possible to add several features that will represent the complex behavior of the material. The aim of this study is to understand the role of the different parameters and the influence of the different features in an advanced Chaboche model adapted to cyclic anisothermal loading. This specific model was also developed in [2],[3]. However, part of this study is based on particular cases where different features of the model are analyzed [4]–[6]. [less ▲]

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailDamage Detection in Structures Based on Principal Component Analysis of Forced Harmonic Responses
Golinval, Jean-Claude ULg

in Procedia Engineering (2017, September)

An approach based on principal component analysis (PCA) is considered here to tackle the problem of structural damage detection. The key idea of PCA is to reduce a large number of measured data to a much ... [more ▼]

An approach based on principal component analysis (PCA) is considered here to tackle the problem of structural damage detection. The key idea of PCA is to reduce a large number of measured data to a much smaller number of uncorrelated variables while retaining as much as possible of the variation in the original data. PCA is applied here to the problem of damage detection in structures submitted to harmonic excitation. When processing vibration measurements, it can be shown that the basis of eigenvectors (called the proper orthogonal modes) span the same subspace as the mode-shape vectors of the monitored structure. Thus the damage detection problem may be solved using the concept of subspace angle between a reference subspace spanned by the eigenvectors of the initial (undamaged) structure and the subspace spanned by the eigenvectors of the current (possibly damaged) structure. The method is illustrated on the example of a real truss structure for damage detection and is combined to a model updating technique for damage localization. [less ▲]

Detailed reference viewed: 9 (0 ULg)
Full Text
Peer Reviewed
See detailSemantic Background Subtraction
Braham, Marc ULg; Pierard, Sébastien ULg; Van Droogenbroeck, Marc ULg

in IEEE International Conference on Image Processing (ICIP), Beijing 17-20 September 2017 (2017, September)

We introduce the notion of semantic background subtraction, a novel framework for motion detection in video sequences. The key innovation consists to leverage object-level semantics to address the variety ... [more ▼]

We introduce the notion of semantic background subtraction, a novel framework for motion detection in video sequences. The key innovation consists to leverage object-level semantics to address the variety of challenging scenarios for background subtraction. Our framework combines the information of a semantic segmentation algorithm, expressed by a probability for each pixel, with the output of any background subtraction algorithm to reduce false positive detections produced by illumination changes, dynamic backgrounds, strong shadows, and ghosts. In addition, it maintains a fully semantic background model to improve the detection of camouflaged foreground objects. Experiments led on the CDNet dataset show that we managed to improve, significantly, almost all background subtraction algorithms of the CDNet leaderboard, and reduce the mean overall error rate of all the 34 algorithms (resp. of the best 5 algorithms) by roughly 50% (resp. 20%). Note that a C++ implementation of the framework is available at http://www.telecom.ulg.ac.be/semantic. [less ▲]

Detailed reference viewed: 82 (21 ULg)
Full Text
See detailLandscape and hydrological controls on the downstream transport of dissolved organic matter in the Congo and Zambezi rivers
Lambert, T; Bouillon, S; Teodoru, CR et al

Conference (2017, August 20)

Detailed reference viewed: 19 (2 ULg)
Full Text
Peer Reviewed
See detailTwenty-year tracking of lighting savings and power density in the residential sector
Attia, Shady ULg

in Energy and Buildings (2017)

Detailed reference viewed: 29 (0 ULg)
Full Text
Peer Reviewed
See detailCompositional gap at La Picada (CSVZ, Chile) results from critical cristallinity and compaction
Vander Auwera, Jacqueline ULg; Namur, Olivier ULg; Coumont, Valentin et al

Poster (2017, August 16)

Detailed reference viewed: 16 (1 ULg)
Full Text
See detailORBi : an institutional repository to promote Open Access
Chalono, Dominique ULg; Thirion, Paul ULg

Conference (2017, August 09)

Detailed reference viewed: 408 (3 ULg)