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See detailImproving our knowledge of rapid geomagnetic field intensity changes observed in Europe between 200 and 1400 AD
Gomez-Paccard, Miriam; Chauvin, Annick; Lanos, Philippe et al

in Earth and Planetary Science Letters (2012), 355-356

vailable archaeomagnetic data indicate that during the past 2500 yr there have been periods of rapid geomagnetic field intensity fluctuations interspersed with periods of almost constant field strength ... [more ▼]

vailable archaeomagnetic data indicate that during the past 2500 yr there have been periods of rapid geomagnetic field intensity fluctuations interspersed with periods of almost constant field strength. Despite Europe being the most widely covered region in terms of archaeomagnetic data the occurrence and the behaviour of these rapid geomagnetic field intensity changes is under discussion and the challenge now is to precisely describe them. The aim of this study is to obtain an improved description of the sharp intensity change that took place in western Europe around 800 AD as well as to investigate if this peak is observed at the continental scale. For this purpose 13 precisely dated early medieval Spanish pottery fragments, four archaeological French kilns and three collections of bricks used for the construction of different French historical buildings with ages ranging between 335 and 1260 AD have been studied. Classical Thellier experiments performed on 164 specimens, and including anisotropy of thermoremanent magnetisation and cooling rate corrections, gave 119 reliable results. The 10 new high-quality mean archaeointensities obtained confirm the existence of an intensity maximum of ∼85 μT (at the latitude of Paris) centred at ∼800 AD and suggest that a previous abrupt intensity change occurred around 600 AD. Together with previously published data from western Europe that we deem to be the most reliable, the new data also suggest the existence of two other abrupt geomagnetic field intensity variations during the 12th century and around the second half of the 13th century AD. High-quality archaeointensities available from eastern Europe indicate that very similar geomagnetic field intensity changes occurred in this region. European data indicate that very rapid intensity changes (of at least 20 μT/century) took place in the recent history of the Earth's magnetic field. The results call for additional high-quality archaeointensities obtained from precisely dated samples and for a selection of the previously published data if a refined description of geomagnetic field intensity changes at regional scales is to be obtained. [less ▲]

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See detailImproving our vision on human cadaveric decomposition chemistry
Stefanuto, Pierre-Hugues ULg; Stadler, S; Perrault, K et al

Conference (2014, April 15)

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See detailImproving Overlay Routing scalability using an Internet Coordinate System
Cantin, François ULg

Doctoral thesis (2012)

Nowadays lots of real time applications are used over the Internet: voice over IP, online video games, etc. For these applications the performance of the path between two communicating nodes is critical ... [more ▼]

Nowadays lots of real time applications are used over the Internet: voice over IP, online video games, etc. For these applications the performance of the path between two communicating nodes is critical. Particularly, most of these applications require small delays between communicating nodes. For these applications, the problem is that the choice of the routes in the Internet is generally not very much guided by performance concerns. It is well known that for lots of node pairs the default Internet path is suboptimal and there exists an alternative path providing a smaller delay between these nodes. In this thesis, we mainly address the problem of finding these alternative paths. Replacing Internet's routing philosophy in order to obtain default paths providing the best performance possible should be a good theoretical solution. However, replacing Internet's routing philosophy by a brand new one is very difficult or even impossible in practice. Another solution is to leave the default routes as they are and to perform indirect routing. Consider a path AB between two nodes A and B. If a path ACB has a smaller delay than AB, then, instead of sending data directly to B, A can send them to C and C can relay them to B. This is called overlay routing because we manage the routing in an overlay network built on top of the Internet (i.e. at the application level). Overlay routing is a promising way to improve the quality of service in the Internet but its main drawback is its poor scalability: measuring the characteristics of the paths, exchanging the measurement results between the nodes and computing the best routes in the full mesh overlay network generally implies a high consumption of resources. In this thesis, our main contribution is the design of a lightweight one-hop overlay routing mechanism improving the latencies: we define criteria that rely on the information provided by an Internet Coordinate System (ICS) in order to provide a small set of potential one-hop shortcuts for any given path in the network with small costs. Our best criterion does not guarantee to find the best shortcut for any given path in a network but, even in networks with hundreds or thousands of nodes, it will restrict the search for potential shortcuts to about one or two percent of the total number of nodes. Even if the estimation-based approach of overlay routing is our main contribution, this thesis also presents general results about routing shortcuts and Internet Coordinate Systems. For an ICS, a routing shortcut is a Triangle Inequality Violation (TIV) and it is often a big problem. Indeed, a TIV will cause estimation errors since, in this particular case, nodes cannot be embedded into any metric space. In this thesis, we study TIVs existing in the Internet and their impact on the Vivaldi ICS. This analysis leads to two contributions. Firstly, we propose criteria to establish, with a high probability of success, if there exists a shortcut or not for a given path AB. Secondly, we propose a Two-Tier architecture for ICSes that mitigates the effect of TIVs on the estimations. Finally, this thesis also discusses the efficiency of two solutions proposed in the literature in order to obtain an ICS that can deal with TIVs. The first one consists in applying non-linear transformations to delays before trying to embed them in a metric space. The second one consists in modelling the estimation problem as a matrix completion problem in order to completely avoid the embedding in a metric space. [less ▲]

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See detailImproving patient positioning accuracy for breast cancer radiation therapy by using the infra red based ExacTrac system
GULYBAN, Akos ULg; Hortobágyi, E.; Sebestyén, Z. et al

in Nowotwory (2008), 58(5), 435-437

We report on a pilot study to investigate for cancer of the breast, the accuracy of patient positioning with the normal standard method (ST) and with the standard method extended with the ExacTrac system ... [more ▼]

We report on a pilot study to investigate for cancer of the breast, the accuracy of patient positioning with the normal standard method (ST) and with the standard method extended with the ExacTrac system (ET). Our work in progress pilot study population consisted of four patients: two positioned using ST and two positioned using ET. The results from the daily electronic portal images showed that with ExacTrac the positional accuracy could be unproved by 50% but with a corresponding increase in overall treatment time of about 2 minutes. [less ▲]

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See detailImproving physical education teachers’ action with overweight students
Cloes, Marc ULg

in Revista Motricidade (2012), 8(S1), 3-4

Nowadays, overweight is one of the most important plagues and many authors believe that the fast increase of this phenomenon during the last decades can be considered as a global epidemic. School has been ... [more ▼]

Nowadays, overweight is one of the most important plagues and many authors believe that the fast increase of this phenomenon during the last decades can be considered as a global epidemic. School has been identified as one of the pillars of the necessary multisectorial approach that must be implemented to fight against this ineworable trend. ... [less ▲]

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See detailImproving pose estimation by building dedicated datasets and using orientation
Azrour, Samir ULg; Pierard, Sébastien ULg; Van Droogenbroeck, Marc ULg

Poster (2016, May 19)

Markerless pose estimation systems are useful for various applications including human- computer interaction, activity recognition, security, gait analysis, and computer-assisted medical interventions ... [more ▼]

Markerless pose estimation systems are useful for various applications including human- computer interaction, activity recognition, security, gait analysis, and computer-assisted medical interventions. They have attracted much interest since the release of low-cost depth cameras such as Microsoft’s Kinect camera. Shotton et al. and Girshick et al. pioneered tractable methods that infer a full-body pose reconstruction in real-time. Despite this technological breakthrough, the accuracy of human pose estimation from single depth images remains insufficient for some applications. Our work aims at building a simulation environment to create images databases suited for any camera position and improving the mainstream machine learning-based pose estimation algorithms. [less ▲]

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See detailImproving probiotic viability and functionality by bioreactors engineering
Nguyen, Huu Thanh ULg

Doctoral thesis (2016)

There is a growing market for probiotic bacteria, but their production is still the subject to technical limitations, i.e. susceptibility to the stress conditions found during upstream and downstream ... [more ▼]

There is a growing market for probiotic bacteria, but their production is still the subject to technical limitations, i.e. susceptibility to the stress conditions found during upstream and downstream operations. In this work, we have investigated the effect of cultivation and drying conditions on Bifidobacterium bifidum MG 25628, a probiotic bacteria being particularly sensitive to bioprocessing conditions. Previous results have shown that microbial physiology, and the ability of microbes to cope with stress, is dependent of the growth rate and the growth phase. It is also known that the preliminary exposure of microbial cells to sub-lethal stress enhance its robustness. Accordingly, the effect of the exposure of B. bifidum in a two-compartment reactor designed in order to expose the strain to different temperature conditions was investigated. We found that the exposure of B. bifidum at 42°C for 1h at the onset of the stationary phase enhanced significantly survival after freeze-drying. It appeared that the increase in cell survival was attributed to the induction of the synthesis and an exopolysaccharide layer surrounding the cells. The method involving the exposure of the strain to sub-lethal temperature stress was further successfully scaled-up to a bioreactor volume of 2000 L. EPS synthesis can also be stimulated by sparing the bioreactor with carbon dioxide. In this context, we investigated the EPS yield in two specific bioreactor designs for the intensification of the CO2 gas-liquid mass transfer, i.e. a trickle bed and a falling-film microreactor. Depending of the operating conditions, these two bioreactor configurations led to a significant improvement in EPS synthesis (around 21 g/L). Extensive comparative proteomic analysis confirmed the impact on CO2 mass transfer on cell physiology, notably by enhancing the intracellular concentration of two key enzymes implied in carbonate uptake, i.e. phosphoenolpyruvate carboxylase and carbamoyl phosphate synthase. Taken altogether, these results point out that biochemical engineering parameters can be used as a very efficient strategy for improving probiotic robustness. Additionally, this non-GMO approach is more suited to the consumer expectations. [less ▲]

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See detailImproving Product Quality and Reliability with Customer Experience Data
Brombacher, Aarnout; Hopma, Eva; Ittoo, Ashwin ULg et al

in Quality and Reliability Engineering International (2011), 28(8), 873886

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See detailImproving properties of recycled concrete aggregates by accelerated carbonation
Zhao, Zengfeng ULg; Remond, Sébastien; Damidot, Denis et al

in Proceedings of the 4th International Conference on Sustainability Construction Materials and Technologies (2016)

Detailed reference viewed: 34 (10 ULg)
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See detailImproving proviral integration site detection with high throughput sequencing
Durkin, Keith ULg; Artesi, Maria ULg; Rosewick, Nicolas et al

Poster (2015, May)

Detailed reference viewed: 5 (0 ULg)
See detailImproving Public Outcomes in Developing Countries. Application of Incentive Theory to Foreign Aid and Public Resource Management
Paul, Elisabeth ULg

Doctoral thesis (2006)

This Ph.D. thesis applies incentive theory – and especially, when relevant, the principal-agent theory – to several aspects of public resource management in developing countries. It uses analytical models ... [more ▼]

This Ph.D. thesis applies incentive theory – and especially, when relevant, the principal-agent theory – to several aspects of public resource management in developing countries. It uses analytical models taking account of realistic constraints of these economies. The first part of the dissertation studies the incentive problems associated with foreign aid management. The second part deals with some “domestic” problems linked with public resource management in those countries. Chapter 2 proposes an analytical framework to guide the design of public expenditure management systems (more precisely, the type of controls a Ministry of Finance could apply to line ministries) according to country-specific parameters. Chapter 3 suggests that, when traditional incentives (sanctions and rewards) fail – which may be the case, at least in the short run, in many developing countries) – increasing public affairs transparency can help improve public outcomes, notably through relying on "informal" accountability systems. Chapter 4 reviews the literature and then draws some important results as to the motivation of public agents. In addition to specific results on the issues targeted in each chapter, this dissertation offers a coherent analytical picture of public resource management in developing countries, and a number of general lessons may be drawn. Improving public outcomes must indeed pass through providing public agents with adequate incentives, so as to align their interests with their principal’s. Different tools may be used, depending on their cost-effectiveness: e.g., controls, incentive premiums, factors acting on non-materialistic motivations or on informal accountability mechanisms. The thesis also proposes some lessons as to the sequencing of reforms dealing with public resource management. [less ▲]

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See detailImproving quality of life in patients with peripheral arterial disease: an important goal.
Kolh, Philippe ULg

in European Journal of Vascular and Endovascular Surgery (2010), 40(5), 626-7

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See detailImproving Retouched Bloom Filter for Trading Off Selected False Positives Against False Negatives
Donnet, Benoît ULg; Baynat, Bruno; Friedman, Timur

in Computer Networks (2010), 54(18), 3373-3387

Where distributed agents must share voluminous set membership information, Bloom fil- ters provide a compact, though lossy, way for them to do so. Numerous recent networking papers have examined the trade ... [more ▼]

Where distributed agents must share voluminous set membership information, Bloom fil- ters provide a compact, though lossy, way for them to do so. Numerous recent networking papers have examined the trade-offs between the bandwidth consumed by the transmis- sion of Bloom filters, and the error rate, which takes the form of false positives. This paper is about the retouched Bloom filter (RBF). An RBF is an extension that makes the Bloom fil- ter more flexible by permitting the removal of false positives, at the expense of introducing false negatives, and that allows a controlled trade-off between the two. We analytically show that creating RBFs through a random process decreases the false positive rate in the same proportion as the false negative rate that is generated. We further provide some simple heuristics that decrease the false positive rate more than the corresponding increase in the false negative rate, when creating RBFs. These heuristics are more effective than the ones we have presented in prior work. We further demonstrate the advantages of an RBF over a Bloom filter in a distributed network topology measurement application. We finally discuss several networking applications that could benefit from RBFs instead of standard Bloom filters. [less ▲]

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See detailImproving RSVP for better support of internet multimedia communications
Mathy, Laurent ULg; Hutchison, D.; Schmid, S. et al

in Multimedia Computing and Systems, 1999. IEEE International Conference on (1999)

Detailed reference viewed: 9 (0 ULg)