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
See detailLocal electron density reconstruction from simultaneous ground-based GNSS and ionosonde measurements
Stankov, Stanimir; Warnant, René ULg; Stegen, Koen

in Geophysical Research Abstracts (2009, April), 11(Abs. No EGU2009-10956),

Detailed reference viewed: 19 (1 ULg)
Full Text
See detailLocal ensemble assimilation scheme with global constraints and conservation
Barth, Alexander ULg; Yan, Yajing ULg; Canter, Martin ULg et al

Poster (2014, April)

Ensemble assimilation schemes applied in their original, global formulation have no problem in respecting linear conservation properties if the ensemble perturbations are setup accordingly. For realistic ... [more ▼]

Ensemble assimilation schemes applied in their original, global formulation have no problem in respecting linear conservation properties if the ensemble perturbations are setup accordingly. For realistic ocean systems, only a relatively small number of ensemble members can be calculated. A localization of the ensemble increment is thus necessary to filter out spurious long-range correlations. However, the conservation of the global property will be lost if the assimilation is performed locally since the conservation requires a coupling between model grid points, which is filtered out by the localization. In the ocean, the distribution of observations is highly inhomogeneous. Systematic errors of the observed parts of the ocean state can lead to spurious systematic adjustments of the non-observed part of the ocean state due to data assimilation. As a result, global properties which should be conserved, increase or decrease in long-term simulations. We propose an assimilation scheme (with stochastic or deterministic analysis steps) which is formulated globally (i.e. for the whole state vector) but where spurious long-range correlations can be filtered out. The scheme can thus be used to enforce global conservation properties and non-local observation operators. Both aspects are indeed linked since one can introduce the global conservation as a weak constraint by using a global observation operator. The conserved property becomes thus an observed value. The proposed scheme is tested with the Kuramoto-Sivashinsky model which is conservative. The benefit compared to the traditional covariance localization scheme (with an ad-hoc step enforcing conservation) where observations are assimilated sequentially is shown. The assimilation scheme is suitable to be implemented on parallel computers where the number of available computing cores is a multiple of the ensemble size. [less ▲]

Detailed reference viewed: 49 (3 ULg)
Full Text
Peer Reviewed
See detailLocal ensemble assimilation scheme with global constraints and conservation
Barth, Alexander ULg; Yan, Yajing ULg; Canter, Martin ULg et al

Conference (2015)

Ensemble assimilation schemes applied in their original, global formulation have no problem in respecting linear conservation properties if the ensemble perturbations are setup accordingly. For realistic ... [more ▼]

Ensemble assimilation schemes applied in their original, global formulation have no problem in respecting linear conservation properties if the ensemble perturbations are setup accordingly. For realistic ocean systems, only a relatively small number of ensemble members can be calculated. A localization of the ensemble increment is thus necessary to filter out spurious long-range correlations. However, the conservation of the global property will be lost if the assimilation is performed locally since the conservation requires a coupling between model grid points, which is filtered out by the localization. In the ocean, the distribution of observations is highly inhomogeneous. System- atic errors of the observed parts of the ocean state can lead to spurious systematic adjust- ments of the non-observed part of the ocean state due to data assimilation. As a result, global properties which should be conserved, increase or decrease in long-term simulations. We propose an assimilation scheme (with stochastic or deterministic analysis steps) which is formulated globally (i.e. for the whole state vector) but where spurious long-range correlations can be filtered out. The scheme can thus be used to enforce global conservation properties and non-local observation operators. Both aspects are indeed linked since one can introduce the global conservation as a weak constraint by using a global ob- servation operator. The conserved property becomes thus an observed value. The proposed scheme is tested with the Kuramoto-Sivashinsky model which is conservative. The benefit compared to the traditional covariance localization scheme (with an ad-hoc step enforcing conservation) where observations are assimilated sequentially is shown. The assimilation scheme is suitable to be implemented on parallel computers where the number of available computing cores is a multiple of the ensemble size. [less ▲]

Detailed reference viewed: 17 (0 ULg)
Peer Reviewed
See detailLocal equating methods in the NEAT design
Janssen, Rianne; Magis, David ULg; San Martin, Ernesto et al

Conference (2009, April)

Detailed reference viewed: 44 (1 ULg)
Full Text
Peer Reviewed
See detailLocal estradiol synthesis in the brain and its implication in male and female sexual motivation of Japanese quail
de Bournonville, Catherine ULg; Schmit, Mélanie; Ball, Gregory F et al

in Trabajos del Instituto Cajal (2013)

Detailed reference viewed: 15 (1 ULg)
Full Text
Peer Reviewed
See detailLocal extinctions of Primates: demographic and genetic effectson vegetation
Culot, Laurence ULg; Galetti, Mauro

in Folia Primatologica : International Journal of Primatology = Internationale Zeitschrift für Primatologie = Journal international de Primatologie (2013), 84(262),

Detailed reference viewed: 51 (6 ULg)
Full Text
Peer Reviewed
See detailLocal food systems in Walloon Region (Belgium): definition and trends in supply and demand
Comps, Samuel ULg; Claustriaux, Jean-Jacques ULg; Vandercammen, Marc et al

Conference (2011, September 02)

Local food systems are one solution to promote local products in different ways and particularly by bringing together producers and consumers. This paper follows different purposes. The term “local food ... [more ▼]

Local food systems are one solution to promote local products in different ways and particularly by bringing together producers and consumers. This paper follows different purposes. The term “local food systems” will be defined as systems mobilizing not more than one intermediate person in a local area, where the exchanges must be monetized and where a relationship between the producer and the consumer is established. Then, a classification of the various initiatives of local food systems will be proposed. Thereafter the results of two studies conducted in the Walloon Region will be presented. The first study was conducted in Wallonia and Brussels in 2010 by the CRIOC to assess consumers’ perceptions and expectations of local products marketing using local food systems. The second one was conducted in 2010 to establish an inventory of local food systems in the Province of Namur. It had four main objectives: to describe categories of local food systems used, to give an overview of products supply, to understand main difficulties encountered by producers and to give benchmarks for the installation. The paper concludes that local food systems provide a wide diversity of selling networks which can be used. However, it is not easy for producers to meet consumers’ needs for local agricultural produce. The paper also puts emphasis on the necessity of including many fields of action to develop local food systems. [less ▲]

Detailed reference viewed: 103 (23 ULg)
Full Text
Peer Reviewed
See detailLocal goat in Kabylie (Chemini and Bouzeguene)
Moula, Nassim ULg; Michaux, Charles ULg; Philippe, François-Xavier ULg et al

Poster (2014, October 17)

The livestock sector plays a dynamic role in the economic development of rural areas in Algeria. Due to its adaptation to harsh environments, goat breeding is practiced in many areas of the country. To ... [more ▼]

The livestock sector plays a dynamic role in the economic development of rural areas in Algeria. Due to its adaptation to harsh environments, goat breeding is practiced in many areas of the country. To the north, it is confined to mountainous areas, but the bulk of the workforce is left in the steppe and semi-desert areas. The goat population in Algeria reached 3.8 million heads, ranking second after sheep. The present work contributes to a better characterisation of local goat in Kabylie for production and reproduction traits. The study was conducted in the regions of Chemini (Bejaia province) and Bouzeguene (Tizi-Ouzou province). A survey was conducted in 29 herds. The results revealed that the overall mean of goats per households was 6.69 ± 2.97. The purposes of keeping goat in Chemini and Bouzguene was private consumption of milk (82.76%) and meat (68.97%) as well as for commercial exchange (62.07%). The Kabyle goat is small (male: 62.23 cm and female: 58.41 cm) with long hair. Its ears are drooping, its convex profile has a slightly pronounced nasal split and its coat colour ranges from dark brown to black. However, the crossbreeding with exotic breeds (mainly with Saanen goat), controlled or uncontrolled, increased the frequency of white coat. The average age at puberty in males was 6.93 ± 1.04 and 7.38 ± 0.94 months in females. The reported age at first kidding and kidding interval were 13.03 ± 0.87 months and 7.83 ± 1.29 months, respectively. [less ▲]

Detailed reference viewed: 47 (15 ULg)
Full Text
Peer Reviewed
See detailLocal head-loss coefficient at the rectangular transition from a free-surface channel to a conduit
Van Nam, Nguyen; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Journal of Hydraulic Engineering (2013), 139(12), 1318-1323

Experimental tests have been performed to observe and determine, in stationary flow conditions, the local head loss at the transition from a free surface channel to a conduit. These investigations ... [more ▼]

Experimental tests have been performed to observe and determine, in stationary flow conditions, the local head loss at the transition from a free surface channel to a conduit. These investigations considered a wide range of discharge and varied dimensions and positions of a rectangular cross section conduit connected to the downstream extremity of a rectangular free surface channel. From the head loss evaluation results, simple analytical expressions to predict the local head loss coefficient value at the rectangular transition from a channel to a conduit are proposed and validated. [less ▲]

Detailed reference viewed: 114 (24 ULg)
See detailLocal Hydrological effects in Membach, Belgium: influence on the long term gravity variation
Van Camp, Michel; Dassargues, A.; Vanneste, K. et al

Conference (2003)

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
See detailLocal Identification of Voltage Emergency Situations
Vournas, Costas; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2008), 23(3), 1239-1248

This paper proposes a simple procedure to identify the onset of long-term voltage instability from the time evolution of the distribution voltages controlled by load tap changers. The moving average of ... [more ▼]

This paper proposes a simple procedure to identify the onset of long-term voltage instability from the time evolution of the distribution voltages controlled by load tap changers. The moving average of sampled measurements is computed and used to trigger local emergency signals. The method is validated on voltage signals obtained from time simulation of a realistic test system. The ability to identify instability in the critical area is demonstrated in three test cases. [less ▲]

Detailed reference viewed: 89 (11 ULg)
Full Text
See detailLocal immune response in canine sino-nasal aspergillosis
Peeters, Dominique ULg

in Proceedings of the 16th Congress of the International Society for Human and Animal Mycology (2006, June)

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailA local influence approach applied to binary data from a psychiatric study.
Jansen, Ivy; Molenberghs, Geert; Aerts, Marc et al

in Biometrics (2003), 59(2), 410-9

Recently, a lot of concern has been raised about assumptions needed in order to fit statistical models to incomplete multivariate and longitudinal data. In response, research efforts are being devoted to ... [more ▼]

Recently, a lot of concern has been raised about assumptions needed in order to fit statistical models to incomplete multivariate and longitudinal data. In response, research efforts are being devoted to the development of tools that assess the sensitivity of such models to often strong but always, at least in part, unverifiable assumptions. Many efforts have been devoted to longitudinal data, primarily in the selection model context, although some researchers have expressed interest in the pattern-mixture setting as well. A promising tool, proposed by Verbeke et al. (2001, Biometrics 57, 43-50), is based on local influence (Cook, 1986, Journal of the Royal Statistical Society, Series B 48, 133-169). These authors considered the Diggle and Kenward (1994, Applied Statistics 43, 49-93) model, which is based on a selection model, integrating a linear mixed model for continuous outcomes with logistic regression for dropout. In this article, we show that a similar idea can be developed for multivariate and longitudinal binary data, subject to nonmonotone missingness. We focus on the model proposed by Baker, Rosenberger, and DerSimonian (1992, Statistics in Medicine 11, 643-657). The original model is first extended to allow for (possibly continuous) covariates, whereafter a local influence strategy is developed to support the model-building process. The model is able to deal with nonmonotone missingness but has some limitations as well, stemming from the conditional nature of the model parameters. Some analytical insight is provided into the behavior of the local influence graphs. [less ▲]

Detailed reference viewed: 16 (3 ULg)
Peer Reviewed
See detailA Local Influence Approach to Sensitivity Analysis of Incomplete Longitudinal Ordinal Data
Van Steen, Kristel ULg; Molenberghs, G.; Verbeke, G. et al

in Statistical Modelling : An International Journal (2001), 1

Detailed reference viewed: 32 (12 ULg)
Full Text
Peer Reviewed
See detailLocal innovations and initiatives in the management of conflicts and health risks in agro-pastoral zones: The SAREL and PASEL projects in the Dakoro, department in Niger
Ibrahim, Habibou; Mormont, Marc ULg; Yamba, Boubacar

in Field Actions Science Report (2014), 7(11),

This article examines two projects concerned with livestock production in the Dakoro region of Niger. It highlights the results obtained in the management of conflicts between livestock producers and crop ... [more ▼]

This article examines two projects concerned with livestock production in the Dakoro region of Niger. It highlights the results obtained in the management of conflicts between livestock producers and crop farmers, and in the reduction of health risks by promoting the involvement and accountability of livestock producer associations in project activities. The collaboration of local stakeholders is an initiative and a local knowledge-sharing opportunity to promote peaceful conflict resolutions in the context of high land pressure and competing agro-pastoral land use. Such institutional, technical and social initiatives improve participatory governance and legitimise decisions at the grassroots level. They have made a significant contribution to prompting social change and to setting the scene for better security for mobile pastoral systems. [less ▲]

Detailed reference viewed: 32 (4 ULg)
See detailLocal ionospheric activity – nowcast and forecast services
Stankov, Stanimir; Warnant, René ULg; Stegen, Koen et al

Conference (2009)

Detailed reference viewed: 17 (0 ULg)
Full Text
Peer Reviewed
See detailLocal ionospheric electron density profile reconstruction in real time from simultaneous ground-based GNSS and ionosonde measurements
Stankov, Stanimir; Stegen, Koen; Muhtarov, Plamen et al

in Advances in Space Research (2011), 47(7), 1172-1180

Detailed reference viewed: 44 (6 ULg)
Full Text
Peer Reviewed
See detailLocal Knowledge in Policy Making
Schoenaers, Frédéric ULg; Delvaux, Bernard

in Policy and Society (2012), 31(2), 106-169

Detailed reference viewed: 49 (6 ULg)
See detailLocal mapping of dissipative vortex motion
Silhanek, Alejandro ULg

Conference (2013, May)

We have recently introduced an experimental technique which combines the spatial resolution of scanning Hall microscopy and sensitivity of ac-susceptibility measurements as a tool to probe the vortex ... [more ▼]

We have recently introduced an experimental technique which combines the spatial resolution of scanning Hall microscopy and sensitivity of ac-susceptibility measurements as a tool to probe the vortex dynamics in superconducting materials. This technique has proven to be particularly adequate to prospect the degree of mobility of each individual vortex, map the pinning landscape, visualize the intra-valley to inter-valley vortex hopping, and reveal the different mobility of vortices and antivortices created by magnetic dots. Furthermore, we have shown that using the phase sensitive character of the local ac-susceptibility technique it is possible to investigate the dissipative response of a single vortex. This technique opens new and exciting possibilities to locally study loss mechanisms in a variety of interesting magnetic systems such as magnetic domain walls. [less ▲]

Detailed reference viewed: 26 (1 ULg)
Full Text
Peer Reviewed
See detailLocal mapping of dissipative vortex motion
Raes, B; Van de Vondel, J; Silhanek, Alejandro ULg et al

in Physical Review. B : Condensed Matter (2012), 86

We explore, with unprecedented single vortex resolution, the dissipation and motion of vortices in a superconducting ribbon under the influence of an external alternating magnetic field. This is achieved ... [more ▼]

We explore, with unprecedented single vortex resolution, the dissipation and motion of vortices in a superconducting ribbon under the influence of an external alternating magnetic field. This is achieved by combining the phase sensitive character of ac susceptibility, allowing us to distinguish between the inductive and dissipative responses, with the local power of scanning Hall probe microscopy. Whereas the induced reversible screening currents contribute only inductively, the vortices do leave a fingerprint in the out-of-phase component. The observed large phase-lag demonstrates the dissipation of vortices at time scales comparable to the period of the driving force (i.e., 13 ms). These results indicate the presence of slow microscopic loss mechanisms mediated by thermally activated hopping transport of vortices between metastable states. [less ▲]

Detailed reference viewed: 43 (10 ULg)