Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
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

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 14 (3 ULg)
Full Text
Peer Reviewed
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)
Full Text
Peer Reviewed
See detailImproving soil conservation through an adapted tillage: experience from the cultivation of potatoes in Bamiléké's hills of Cameroon
Djoukeng, Henri Grisseur ULg; Tankou, Christopher Mubeteneh; Degré, Aurore ULg

Poster (2014, May 14)

The western highlands of Cameroon are an area where the population density and growth rates are the highest in the country. In this region, the main activity is agriculture, and rivers are the main source ... [more ▼]

The western highlands of Cameroon are an area where the population density and growth rates are the highest in the country. In this region, the main activity is agriculture, and rivers are the main source of safe drinking water. Lacks of arable land and especially against very complex land tenure, farmers are increasingly exploiting the hills (9-30 % slope) for the production of vegetable crops, mainly potatoes. The methods of preparation of soil found there are ridging in the direction of the slope and the culture dish. These practices promote erosion by runoff, generally compromises the multiple functions of agriculture, and in particular the environmental function (soil degradation, pollution and silting up of rivers) and the production function (incomes). In order to ensure soil stability and maintain good water quality of rivers, we put it up a new way of preparing the ground: the tied ridging. To quantify the effectiveness of the latter, we conducted tests of erosion by runoff with Wischmeier’s plots on the most exploited slopes, namely 11% and 29%. The run-off water and sediments were collected per plot and per block after every rain. The first analyses show that there is a significant difference between the culture dish or ridging along the slope and tied ridging. The major constraint of this practice lies in the increase of about 17% of the labor. Tied ridging reported losses in average land 16% lower compared with the ridging in the direction of the slope and 22% compared with the culture dish, he also presented higher yields of 65 % compared with the culture dish and the ridging in the direction of the slope. Despite the hardship, the test results have convinced the participants and some curious farmers which have adopted the technology during the next growing season. [less ▲]

Detailed reference viewed: 20 (11 ULg)
Peer Reviewed
See detailIMPROVING SOIL ORGANIC CARBON (SOC) PREDICTION BY FIELD SPECTROMETRY IN BARE CROPLAND BY REDUCING THE DISTURBING EFFECT OF SOIL ROUGHNESS
Denis, Antoine ULg; Tychon, Bernard ULg; Stevens, Antoine et al

in Geoscience and Remote Sensing Symposium, 2009 IEEE International, IGARSS 2009 (2009, July 17)

The spatial estimation of Soil Organic Carbon (SOC) at large scale in outdoor condition is an important issue. It has been largely demonstrated that diffuse reflectance spectroscopic techniques, are ... [more ▼]

The spatial estimation of Soil Organic Carbon (SOC) at large scale in outdoor condition is an important issue. It has been largely demonstrated that diffuse reflectance spectroscopic techniques, are efficient for SOC determination in field conditions. However these methods are influenced by disturbing factors such as soil water content, vegetation residues and surface roughness, the later being the object of this study. Our laboratory experiments showed that the accuracy of SOC prediction from shadowed soil samples with spectroscopy techniques decreases with increasing soil shadow. In this study a new methodology using a digital camera for identifying and correcting the effect of soil shadow on field reflectance spectra measured with an Analytical Spectral Devices (ASD) during field campaign in bare crop lands has been elaborated and tested. Results showed that the proposed shadow correction method enables improving significantly SOC prediction accuracy and performs better than traditionally used methods consisting in automatic signal processing. [less ▲]

Detailed reference viewed: 85 (29 ULg)
Full Text
Peer Reviewed
See detailImproving solar dryers' performancs using design and thermal heat storage
Bennamoun, Lyes ULg

in Food Engineering Reviews (2013)

Detailed reference viewed: 26 (2 ULg)
Full Text
See detailImproving spatial information extraction for local and regional authorities using Very-High-Resolution data - geometrical aspects
Devriendt, Dennis; Goossens, Rudi; Taillieu, Kristof et al

in Oluić, Marinko (Ed.) New Strategies for European Remote Sensing (2005)

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of ... [more ▼]

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of value-added products that fulfill some of the actual information needs, as expressed by Belgian authorities at the local and at the regional level. One of the technical research modules is focussing on the geometrical aspects of VHR data processing. The geometric precision of VHR data (QuickBird, IKONOS) is systematically evaluated, more specific for an urban and suburban environment using the GCP information obtained by GPS measurements. The 2D-georeferenced images is compared with ortho-rectified images in terms of their geometric accuracy. This will provide useful information about the limitations of 2Dcorrected data, and the necessity of acquiring ortho-rectified data, for different kinds of applications in each of the studied areas. The oblique viewing angle of images produced by VHR sensors like IKONOS and QuickBird has a strong influence on the geometrical displacement of objects, and on the occurrence of hidden areas in the image. The degree of displacement and the percentage of hidden areas are determined by the interaction between viewing angle, position of the sun, object height, and terrain characteristics (slope, aspect). In other words, the range of viewing angles that can be considered acceptable for purchasing an image of a certain area will depend on the morphological characteristics of the area. To study the interaction between all parameters involved, a theoretical model is implemented. First, the model is used to systematically study the impact of viewing angle on object displacement, shadow length and size of hidden areas in an image, by simultaneously varying the different morphological parameters. Next, the impact of viewing angle on the geometry of the image is simulated using the theoretical model and a DSM from aerial photography. The geometrical accuracy of a DSM from VHR data is compared with the accuracy of the DSM, derived from aerial photography at scales of 1:12000 and 1:4000). The satellite-derived DSM is used for ortho-rectification of VHR imagery. The accuracy of the ortho-rectified images is compared with ortho-rectifications of the same images, based on the aerial photo DSM. [less ▲]

Detailed reference viewed: 47 (8 ULg)
Full Text
See detailImproving spatial information extraction for local and regional authorities using Very-High-Resolution data - geometric aspects.
Devriendt, Dennis; Goossens, Rudi; De Wulf, Alain et al

in International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences (2003), 34(XXX),

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of ... [more ▼]

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of value-added products that fulfil some of the actual information needs, as expressed by Belgian authorities at the local and at the regional level. To accomplish this goal the proposal addresses both technical and user-oriented issues, and builds on the experience of five research teams, each with its own background and particular know-how. The most important objectives of the project are: - to define optimal methods for improved spatial information extraction from high- and very-high resolution data, based on innovative processing techniques; - to identify useful EO-applications at the level of local and regional decision making that are made possible by applying the information extraction methods that will be developed; in this case especially 3D information - to define and develop value-added core data products that will support these applications, and that can be consulted with easy-to-use, widely available IT-tools (CD-ROM, Internet, …). One of the technical research modules is focussing on the geometrical aspects of VHR data processing. In terms of spatial resolution, VHR data have the required level of detail to resolve individual objects in the landscape, in a similar way as airborne data. As such, they have the potential of becoming a useful data source for the extraction of detailed, object-related information, and for the production of large-scale cartographic reference data. The geometry of VHR sensor data, however, completely differs from the geometry of aerial photographs (Bethel et al., 2001). Research is going on to evaluate the geometric qualities of present and future VHR standard data products, from the moment they become available, and to examine what level of geometric accuracy is attained with these data, depending on image parameters, processing strategies, and terrain characteristics (Zhou and Li, 2000). The main objectives of the research module on geometric aspects of VHR data processing are: a) to define an optimal procedure for the derivation of envelope DSMs (Digital Surface Models) and ortho-photoplans from VHR data; b) to develop a theoretical model to study the effect of the oblique viewing angle of VHR data on image displacements caused by building height and relief; c) to evaluate the geometric accuracy of satellite-derived envelope DSMs and ortho-corrected image data in comparison with similar products obtained by means of large-scale aerial photography. The module about geometrical aspects is divided into six specific tasks. a) GPS database creation b) Creation of reference envelope DSMs based on aerial photography c) Ortho-rectification of VHR images and aerial photography based on reference DSMs d) Evaluation of the quality of VHR geo-referenced data e) Modelling of displacements caused by terrain morphology and sensor viewing angle f) Development of envelope DEMs from VHR stereoscopic imagery The project is now in the stage where the quality of the georeferenced and orthorectified data is evaluated. [less ▲]

Detailed reference viewed: 35 (2 ULg)
Full Text
Peer Reviewed
See detailImproving strategies for detecting genetic patterns of disease susceptibility in association studies
Calle, M. L.; Urrea, V.; Malats, N. et al

in Statistics in Medicine (2008), 27(30), 6532-6546

Detailed reference viewed: 25 (6 ULg)
Full Text
Peer Reviewed
See detailImproving TCP in wireless networks with an adaptive machine-learnt classifier of packet loss causes
El Khayat, Ibtissam; Geurts, Pierre ULg; Leduc, Guy ULg

in Lecture Notes in Computer Science (2005, May), 3462

TCP understands all packet losses as buffer overflows and reacts to such congestions by reducing its rate. In hybrid wired/wireless networks where a non negligible number of packet losses are due to link ... [more ▼]

TCP understands all packet losses as buffer overflows and reacts to such congestions by reducing its rate. In hybrid wired/wireless networks where a non negligible number of packet losses are due to link errors, TCP is unable to sustain a reasonable rate. In this paper, we propose to extend TCP Newreno with a packet loss classifier built by a supervised learning algorithm called 'decision tree boosting'. The learning set of the classifier is a database of 25,000 packet loss events in a thousand of random topologies. Since a limited percentage of wrong classifications of congestions as link errors is allowed to preserve TCP-Friendliness, our protocol computes this constraint dynamically and tunes a parameter of the classifier accordingly to maximise the TCP rate. Our classifier outperforms the Veno and Westwood classifiers by achieving a higher rate in wireless networks while remaining TCP-Friendly. [less ▲]

Detailed reference viewed: 30 (5 ULg)
Full Text
See detailImproving Teaching: A Need for Combined Strategies
Poumay, Marianne ULg

Scientific conference (2009, October 30)

The presentation will illustrate the efforts of the University of Liège in that new international trend: valorizing good teaching through : • portfolios, • training the teachers (certificates and degree ... [more ▼]

The presentation will illustrate the efforts of the University of Liège in that new international trend: valorizing good teaching through : • portfolios, • training the teachers (certificates and degree granting), • helping faculty implement pedagogical innovations, • deploying a web portal with multiple tools serving autonomous improvement, notably in eLearning. Could some of those tools be shared, in a Charter perspective? [less ▲]

Detailed reference viewed: 35 (11 ULg)
Full Text
Peer Reviewed
See detailImproving the Accuracy of Monitoring Great Apes in the Wild: A Case Study from Southeast Cameroon
Tagg, Nikki; Willie, Jacob; Petre, Charles-Albert ULg

in Folia Primatologica : International Journal of Primatology = Internationale Zeitschrift für Primatologie = Journal international de Primatologie (2013), 84

Detailed reference viewed: 11 (3 ULg)
Peer Reviewed
See detailImproving the action of insulin.
Lefebvre, Pierre ULg; Scheen, André ULg

in Clinical & Investigative Medicine = Médecine Clinique et Experimentale (1995), 18(4), 340-7

Improving the action of insulin is a relatively new concept in diabetes management. Insulin sensitivity can be improved by reduction of excessive body weight, regular physical activity and, possibly, by ... [more ▼]

Improving the action of insulin is a relatively new concept in diabetes management. Insulin sensitivity can be improved by reduction of excessive body weight, regular physical activity and, possibly, by correcting a subclinical magnesium deficiency. Pharmacological means of improving insulin action include metformin, antiobesity serotoninergic agents and, possibly, benfluorex. New compounds aiming at improving the action of insulin are in development and include thiazolidinedione derivatives (known as "insulin sensitizers"), inhibitors of adipose tissue lipolysis (e.g. acipimox), and inhibitors of free fatty acid oxidation (e.g. etomoxir). Avoidance of drugs that reduce insulin sensitivity, such as beta blockers and thiazide diuretics, is recommended. Finally, cigarette smoking is associated with resistance to insulin but it remains to be demonstrated that cessation of cigarette smoking does in fact increase sensitivity to insulin. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailImproving the alkalophilic performances of the Xyl1 xylanase from Streptomyces sp S38: Structural comparison and mutational analysis
De Lemos Esteves, Frédéric ULg; Gouders, T.; Lamotte-Brasseur, J. et al

in Protein Science : A Publication of the Protein Society (2005), 14(2), 292-302

Endo-beta-1,4-xylanases of the family 11 glycosyl-hydrolases are catalytically active over a wide range of pH. Xyl1 from Streptomyces sp. S38 belongs to this family, and its optimum pH for enzymatic ... [more ▼]

Endo-beta-1,4-xylanases of the family 11 glycosyl-hydrolases are catalytically active over a wide range of pH. Xyl1 from Streptomyces sp. S38 belongs to this family, and its optimum pH for enzymatic activity is 6. Xyn11 from Bacillus agaradhaerens and XylJ from Bacillus sp. 41M-1 share 85% sequence identity and have been described as highly alkalophilic enzymes. In an attempt to better understand the alkalophilic adaptation of xylanases, the three-dimensional structures of Xyn11 and Xyl1 were compared. This comparison highlighted an increased number of salt-bridges and the presence of more charged residues in the catalytic cleft as well as an eight-residue-longer loop in the alkalophilic xylanase Xyn11. Some of these charges were introduced in the structure of Xyl1 by site-directed mutagenesis with substitutions Y16D, S18E, G50R, N92D, A135Q, E139K, and Y186E. Furthermore, the eight additional loop residues of Xyn11 were introduced in the homologous loop of Xyl1. In addition, the coding sequence of the XylJ catalytic domain was synthesized by recursive PCR, expressed in a Streptomyces host, purified, and characterized together with the Xyl1 mutants. The Y186E substitution inactivated Xyl1, but the activity was restored when this mutation was combined with the G50R or S18E substitutions. Interestingly, the E139K mutation raised the optimum pH of Xyl1 from 6 to 7.5 but had no effect when combined with the N92D substitution. Modeling studies identified the possible formation of an interaction between the introduced lysine and the substrate, which could be eliminated by the formation of a putative salt-bridge in the N92D/E139K mutant. [less ▲]

Detailed reference viewed: 48 (13 ULg)
Full Text
Peer Reviewed
See detailImproving the bias/variance tradeoff of decision trees - towards soft tree induction
Geurts, Pierre ULg; Olaru, Cristina; Wehenkel, Louis ULg

in Engineering intelligent systems (2001), 9

One of the main difficulties with standard top down induction of decision trees comes from the high variance of these methods. High variance means that, for a given problem and sample size, the resulting ... [more ▼]

One of the main difficulties with standard top down induction of decision trees comes from the high variance of these methods. High variance means that, for a given problem and sample size, the resulting tree is strongly dependent on the random nature of the particular sample used for training. Consequently, these algorithms tend to be suboptimal in terms of accuracy and interpretability. This paper analyses this problem in depth and proposes a new method, relying on threshold softening, able to significantly improve the bias/variance tradeoff of decision trees. The algorithm is validated on a number of benchmark problems and its relationship with fuzzy decision tree induction is discussed. This sheds some light on the success of fuzzy decision tree induction and improves our understanding of machine learning, in general. [less ▲]

Detailed reference viewed: 47 (2 ULg)
See detailImproving the catabolic functions in desiccation-tolerant soil bacteria in view of their use in bioaugmentation.
Weekers, F.; Jacques, Ph.; Springael, D. et al

Poster (1998, May 08)

Detailed reference viewed: 3 (0 ULg)
See detailImproving the catabolic functions in dessication-tolerant soil bacteria in view of their use in bioaugmentation
Weekers, F.; Jacques, Ph.; Springael, D. et al

Poster (1998, May)

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailImproving The Catabolic Functions Of Desiccation-Tolerant Soil Bacteria
Weekers, F.; Jacques, P.; Springael, D. et al

in Applied Biochemistry and Biotechnology (1999), 77-9

Detailed reference viewed: 5 (0 ULg)