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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 ▲]

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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 ▲]

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See detailImproving solar dryers' performancs using design and thermal heat storage
Bennamoun, Lyes ULg

in Food Engineering Reviews (2013)

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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 ▲]

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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 ▲]

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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

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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 ▲]

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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 ▲]

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See detailImproving tetanus prophylaxis in the emergency department: a prospective, double-blind cost-effectiveness study.
STUBBE, Muriel; MORTELMANS, Luc; DESRUELLE, Didier et al

in Emergency Medicine Journal (2007), 24

BACKGROUND: The choice of tetanus prophylaxis for patients with wounds depends on obtaining their vaccination history, which has been demonstrated to be unreliable. Use of a rapid immunoassay (Tétanos ... [more ▼]

BACKGROUND: The choice of tetanus prophylaxis for patients with wounds depends on obtaining their vaccination history, which has been demonstrated to be unreliable. Use of a rapid immunoassay (Tétanos Quick Stick, the TQS), combined with knowledge of certain demographic characteristics, may improve the evaluation of tetanus immunity and thus help to avoid inadequate prophylactic measures and reduce costs. OBJECTIVES: To evaluate the contribution of the TQS in the choice of tetanus prophylaxis and to perform a cost-effectiveness analysis. The final aim was to define the place of the TQS in a modified algorithm for assessment of tetanus immunity in the emergency department. METHOD: In this Belgian prospective, double-blind, multicentre study, 611 adult patients with a wound were included; 498 (81.5%) records were valid. The TQS test was performed by a nurse before the vaccination history was taken and the choice of prophylaxis was made, using the official algorithm (Belgian Superior Health Council), by a doctor who was unaware of the TQS result. RESULTS: The prevalence of protective anti-tetanus immunity was 74.1%. Immunity was lower in older patients and in female patients. The TQS was a cost-effective tool for patients presenting with a tetanus-prone wound and considered from the vaccination history to be unprotected. Use of the TQS would have improved management in 56.9% (95% CI 47.7% to 65.7%) of patients by avoiding unnecessary treatments, leading to a reduction in the mean cost per patient (10.58 euros/patient with the TQS versus 11.34 euros/patient without). The benefits of the TQS use were significantly greater in patients <61 years old: unnecessary treatment would have been avoided in 76.9% (95% CI 65.8% to 85.4%) of cases and the mean cost per patient reduced to 8.31 euros. CONCLUSION: In selected patients, the TQS is a cost-effective tool to evaluate tetanus immunity. An algorithm is proposed for ED assessment of tetanus immunity integrating age and the TQS result. [less ▲]

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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

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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 ▲]

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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 ▲]

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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 ▲]

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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)

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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: 6 (0 ULg)
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See detailImproving the Energy Efficiency of the Building Stock: A Bottom-up Model and its Application in an Online Interactive Portal
Cuvellier, Simon; Marique, Anne-Françoise ULg; Reiter, Sigrid ULg

in Proceedings of PLEA 2014 (2014)

There is an urgent need to reduce energy uses in new and retrofitted buildings. In Europe, energy consumption in the building sector still represents more than 40% of the final energy use. Emerging ... [more ▼]

There is an urgent need to reduce energy uses in new and retrofitted buildings. In Europe, energy consumption in the building sector still represents more than 40% of the final energy use. Emerging countries are also concerned by such issues at even wider levels because of the huge demographic growth they are witnessing. Numerous research studies have highlighted the need to produce more efficient buildings, but also to retrofit the existing building stock. However, research methods and tools that allow a precise quantification of energy uses in buildings and energy savings related to various actions (insulating the roofs, changing the glazing, behavioral changes, etc.) are mainly dedicated to trained professional users, thus neglecting the huge potential energy savings that is linked to individual actions undertaken by citizens in their dwellings. In this context, the main aim of our research is to raise awareness of energy efficiency in residential buildings and encourage positive changes to the energy efficiency of the building stock, starting at the individual scale. This paper first presents the methodology that allows a precise energy assessment (heating, cooling, ventilation, lighting, appliances and cooking) of buildings (at the house, neighborhood, city and region scales) on the basis of a “bottom-up” approach. This methodology uses a typological classification of buildings, thermal simulations and local surveys. In this paper, this methodology is applied to the Walloon (Belgium) building stock. Many parameters are defined and taken into account to capture the specificities of numerous types of buildings (e.g., the number of floors, common ownership, orientation, thermal performances, ventilation, etc.). Several occupation modes are modelled to capture the impact of occupants’ behavior on energy consumption. To take into account the impact of urban form, correction factors are defined and applied according to the type of neighborhoods in which the buildings are located. All things considered, 250,000 individual results are obtained and stored in a huge database. Linear extrapolations and correction factors are used to extrapolate and apply these results to any type of residential building in Wallonia. This methodology is then used to develop an online portal that aims to strengthen citizens’ awareness of the necessity for ecological changes in the building sector and encourage individual actions to improve the energy efficiency of buildings. This tool allows for a transfer of the main results of a two-year scientific research effort to citizens in a very simple and intuitive way. Although the results presented in this paper are focused on Wallonia (Belgium), the research is easily reproducible to other territories by adapting local parameters. [less ▲]

Detailed reference viewed: 12 (4 ULg)