Evapotranspiration (ET) is a significant hydrological process. It can be studied and estimated using remote sensing based methods at multiple spatial and temporal scales. Most commonly and widely used remote sensing based methods to estimate actual evapotranspiration (AET) are a) methods based on energy balance equations, b) vegetation coefficient based method and c) contextual methods. These three methods require reflectance and land surface temperature (LST) data measured at optical and thermal portion of the electromagnetic spectrum. However, these data are available only for clear sky conditions and fail to be retrieved under overcast conditions creating gaps in the data, which result in discontinuous of AET product. Moreover, energy balance equation based methods and evaporative fraction (EF) based contextual methods are difficult to apply over overcast conditions. In this context, vegetation coefficient based (Tasumi et al., 2005; Allen et al., 2005) and microwave remote sensing based methods can be applied under cloudy sky conditions (Sun et al., 2012), since microwave radiations can penetrate through clouds, but these data are available at coarse resolution. In the vegetation coefficient method temporal upscaling can be avoided. Therefore in this research vegetation coefficient based method is employed over Cauvery basin to estimate daily AET for clear and cloudy sky conditions. Required critical variables for this method such as reference evapotranspiration (ETo) and vegetation coefficients are obtained using LST and optical vegetation indices for all sky conditions. In this study, all sky conditions refer to both clear and cloudy sky conditions. Most important variable for estimation of ETo using radiation and temperature based models is air temperature (Ta). In this study, for better accuracy of Ta, two satellite based approaches namely, Temperature Vegetation Index (TVX) and Advance Statistical Approaches (ASA) were evaluated. In the TVX approach, in addition to traditional Normalized Difference Vegetation Index (NDVI), other vegetation indices such as Enhanced Vegetation Index (EVI) and Global Vegetation Moisture Index (GVMI) were also examined. In case of ASA, bootstrap technique was used to generate calibration and validation samples and Levenberg Marquardt algorithm was used to find the solution of the models. The better of the Ta results obtained out of these two approaches were employed in the ETo models and are referred as Ta based ETo models. Instead of Ta, processed LST data obtained directly from the satellite (Aqua/Moderate Resolution Imaging Spectroradiometer (MODIS)) was applied in the ETo models and these are referred as LST based ETo models. These Ta and LST based Hargreaves-Samani (H-S), Makkink (Makk) and Penman Monteith Temperature (PMT) models were evaluated by comparing with the FAO56 PM model. Additionally, simple LST based equation (SLBE) proposed by Rivas et al. (2004) was also examined. Required solar radiation (Rs) data for ETo estimation was obtained from Kalpana1/VHRR satellite data. Results implied that, Ta based PMT model performed better than the Ta based H-S, Makk and SLBE with less RMSE, MAPE and MBE values for all land cover classes and for various climatic regions for clear sky conditions. LST based H-S, PMT, Makk and Ta based Makkink advection models predominantly overestimated ETo for the study region. In the case of TVX approach, to estimate maximum Ta (Tmax), GVMI performed better than NDVI and EVI. Nevertheless, TVX approach poorly estimated Tmax in comparison with statistical approach. ASA performed better for both Tmax and minimum Ta. This study demonstrates the applicability of satellite based Ta and ETo models by considering very few variables for clear sky conditions. Spatially distributed vegetation coefficients (Kv) data with high temporal resolution is another important variable in vegetation coefficient method for daily AET estimation and also it is in demand for crop condition assessment, irrigation scheduling, etc. But available Kv models application hinders because of two main reasons i.e 1) Spectral reflectance based Kv accounts only for transpiration factor but not evaporation, which fails to account for total AET. 2) Required optical spectral reflectances are available only during clear sky conditions, which creates gaps in the Kv data. Hence there is a necessity of a model which accounts for both transpiration and evaporation factors and also gap filling method, which produces accurate continuous quantification of Kv values. Therefore, different combinations of EVI, GVMI and temperature vegetation dryness index (TVDI) have been employed in linear and non linear regression techniques to obtain best model. This best Kv model had been compared with Guershman et al. (2009) Kv model. To fill the gaps in the data, initially, temporal fitting of Kv values have been examined using Savitsky-Goley (SG) filter for three years of data (2012 to 2014), but this fails when sufficient high quality Kv values were unavailable. In this regard, three gap filling techniques namely regression, Artificial Neural Networks (ANNs) and interpolation techniques have been analyzed. Microwave polarization difference index (MPDI) has been employed in ANN technique to estimate Kv values under cloudy sky conditions. The results revealed that the combination of GVMI and TVDI using linear regression technique performed better than other combinations and also yielded better results than Guershman et al. (2009) Kv model. Furthermore, the results indicated that SG filter can be used for temporal fitting and for filling the gaps, regression technique can be used as it performed better than other techniques for Berambadi station. Land Surface Temperature (LST) with high spatiotemporal resolution is required in the estimation of ETo to obtain AET. MODIS is one of the most commonly used sensors owing to its high spatial and temporal availability over the globe, but is incapable of providing LST data under cloudy conditions, resulting in gaps in the data. In contrast, microwave measurements have a capability to penetrate under clouds. The current study proposes a methodology by exploring this property to predict high spatiotemporal resolution LST under cloudy conditions during daytime and night time without employing in-situ LST measurements. To achieve this, ANN based models were employed for different land cover classes, utilizing MPDI at finer resolution with ancillary data. MPDI was derived using resampled (from 0.250 to 1 km) brightness temperatures (Tb) at 36.5 GHz channel of dual polarization from Advance Microwave Scanning Radiometer (AMSR)-Earth Observing System and AMSR2 sensors. The proposed methodology was quantitatively evaluated through three performance measures namely correlation coefficient (r), Nash Sutcliffe Efficiency (NSE) and Root Mean Square Error (RMSE). Results revealed that during daytime, AMSR-E(AMSR2) derived LST under clear sky conditions corresponds well with MODIS LST resulting in values of r ranging from 0.76(0.78) to 0.90(0.96), RMSE from 1.76(1.86) K to 4.34(4.00) K and NSE from 0.58(0.61) to 0.81(0.90) for different land cover classes. For night time, r values ranged from 0.76(0.56) to 0.87(0.90), RMSE from 1.71(1.70) K to 2.43(2.12) K and NSE from 0.43 (0.28) to 0.80(0.81) for different land cover classes. RMSE values found between predicted LST and MODIS LST during daytime under clear sky conditions were within acceptable limits. Under cloudy conditions, results of microwave derived LST were evaluated with Ta which indicated that the approach performed well with RMSE values lesser than the results obtained under clear sky conditions for land cover classes for both day and nighttimes. These predicted LSTs can be applied for the estimation of soil moisture in hydrological studies, in climate studies, ecology, urban climate and environmental studies, etc. AET was estimated for all sky conditions using vegetation coefficient method. Essential parameter ETo under cloudy conditions was estimated using LST and Ta based PMT and H-S models and required solar radiation (Rs) in these two models estimated using equation proposed by Samani (2000). In this equation it was found that the differences between LSTmax or Tmax and LSTmin or Tmin could able to capture the variations due to cloudy sky conditions and hence can be used for estimating ETo under cloudy sky conditions. Results revealed that the estimated Rs correlated well with observed Rs for Berambadi station under cloudy conditions for the year 2013. PMT based ETo values were corresponded with observed ETo under cloudy sky condition. The difference between LST and Ta was less during cloudy conditions, therefore LST or Ta can be used as the only input in temperature based PMT model to estimate ETo. AET estimated correlated well with the observed AET values for clear and cloudy sky conditions. In addition, AET estimated using vegetation coefficient method was compared with two source energy balance (TSEB) method developed by Nishida et al. (2003) under clear sky conditions. It was found that the improved vegetation coefficient method performed better than the TSEB method for Berambadi station. Other microwave vegetation indices such as Microwave Vegetation Indices (MVIs) and Emissivity Difference Vegetation Index (EDVI) are available in literature. Therefore in this study, MVIs are used to predict LST under cloudy conditions using proposed methodology to check whether the MVIs could yield better LST values. Results showed that MPDI performed better than MVIs to predict LST under cloudy sky conditions. Furthermore, MPDI obtained using dual polarizations of 37 GHz channel Tb has advantage of having fine spatial resolution compared to MVIs, as it requires Tb of 19 GHz in addition to Tb of 37 GHz channel which is of coarse resolution and therefore uncertainties resulting from re-sampling technique can be minimized. x

Les méthodes et les outils de génération automatique ou semi-automatique de modèles 3D urbains se développent rapidement, mais l’évaluation de la qualité de ces modèles et des données spatiales sur lesquelles ils s’appuient n’est que rarement abordée. Notre objectif est de proposer une approche multidimensionnelle standard pour évaluer la qualité des modèles 3D de bâtiments en 1D, 2D et 3D. Deux méthodes sont présentées pour l'évaluation 1D. La première se base sur l’analyse de l’erreur moyenne quadratique en X, Y et Z. La deuxième solution s’appuie sur les instructions parues au Journal Officiel du 30 octobre 2003 et exigeant le respect de classes de précisions. L'approche que nous proposons se penche sur le calcul d'indices de qualité fréquemment rencontrés dans la littérature. L'originalité de notre approche réside dans le fait que les modèles employés en entrée ne se limitent pas au mode raster, mais s'étendent au mode vecteur. Il semble évident que les modèles définis en mode vecteur s'avèrent plus fidèles à la réalité qu'en mode raster. Les indices de qualité 2D et 3D calculés montrent que les modèles 3D de bâtiments extraits à partir des couples d’images stéréoscopiques sont cohérents. Les modèles reconstruits à partir du LiDAR sont moins exacts. En conclusion, cette thèse a abouti à l’élaboration d’une approche d’évaluation multidimensionnelle de bâtiments en 3D. L’approche proposée dans cette thèse est adaptée et opérationnelle pour des modèles vectoriels et rasters de bâtiments 3D simplifiés. / Methods and tools for automatic or semi-automatic generation of 3D city models are developing rapidly, but the quality assessment of these models and spatial data are rarely addressed. A comprehensive evaluation in 3D is not trivial. Our goal is to provide a standard multidimensional approach for assessing the quality of 3D models of buildings in 1D, 2D and 3D. Two methods are applied. The first one is done by computing Root Mean Square Errors (RMSE) based on the deviations between both models (reference and test), in X, Y and Z directions. Second method is performed by applying the French legal text (arrêté sur les classes de précision) that is based on the instructions published in the Official Journal from October 30, 2003. These indices pass through the space discretization in pixels or voxels for measuring the degree of superposition of 2D or 3D objects. The originality of this approach is built on the fact that the models used as input are not only limited to raster format, but also extended to vector format. The results of statistics of the quality indices calculated for assessing the building models show that the 3D building models extracted from stereo-pairs are close from each other. Also, the models reconstructed from LiDAR are less accurate than the models reconstructed from aerial images alone. In conclusion, the quality evaluation of 3D building models has been achieved by applying the proposed multi-dimensional approach. This approach is suitable for simplified 3D building vector models created from aerial images and/or LiDAR datasets.

In order for an economy to survive and thrive it requires resources. Water is a resource that not only the economy is dependent on but also ecological and human communities. The deteriorated state of South African rivers suggests the intensive use of the country’s freshwater reserves by the population and industry. Such a source of freshwater is the Wonderfonteinspruit. It flows through an area that requires water for gold mining that has taken place in the area for more than 120 years. Furthermore, the Wonderfonteinspruit runs past communities such as Bekkersdal and eventually forms part of the source waters for the Boskop Dam, the main drinking water reservoir for Potchefstroom. Literature suggests that the Wonderfonteinspruit is impacted by anthropogenic activities, in particular impacts associated with both historical and current gold mining activities. The Wonderfonteinspruit has its origin in the Tudor Dam in Krugersdorp (now Mogale City), and then flows into Donaldson Dam from where it is piped in a 32 km long pipeline, before its confluence with the Mooi River which subsequently flows into the Boskop Dam. The study area specifically focuses on the Upper Wonderfonteinspruit from just downstream of the Donaldson Dam to just upstream of the dam. The study area was selected due to the close proximity of the Donaldson Dam to the community of Bekkersdal which formed the second part of the investigation for this thesis. Bekkersdal is primarily a mining community that has historically faced issues with sufficient land provision, housing, unemployment and service delivery. It is located in the Gauteng Province and falls under the jurisdiction of Westonaria Local Municipality. Recent protests by community members have occurred due to the lack of service delivery and inappropriate development of infrastructure with regards to water services. Due to the close proximity of Bekkersdal to the Wonderfonteinspruit (as it is situated on the border of the Donaldson Dam) the community provided an ideal study area to explore the use of the river by the community. In order to determine the relationship between the Wonderfonteinspruit and the community of Bekkersdal the study comprised two parts: during the first part of the study, the ecological state of the Wonderfonteinspruit was determined through the evaluation of the quality of water, sediment and biota within the river; while in the second part an assessment of Bekkersdal (both formal and informal sections) was undertaken through the use of questionnaires in order to determine past, current and future water use of both municipal water and water sourced from the Wonderfonteinspruit. The final outcomes of both the environmental and social assessments were then compared with national and international standards. Water quality assessment of the Wonderfonteinspruit was done by assessing the following: - in situ water quality parameters (such as pH, total dissolved solids and dissolved oxygen) - metal and ionic composition analysis of water samples using inductively coupled plasma mass spectrophotometry (ICP-MS) - nutrient loads using a spectrophotometer and Spectroquant® test kits - bacteriological quality by determining presence of total coliforms and faecal coliforms through the growth of bacterial cultures on M-ENDO and m-FC agar plates - the Physico-chemical Driver Assessment Index (PAI) was applied according to DWAF 2008 - statistical relevance between sites and results through principal component analysis (PCA) Finally, these results, where applicable, were compared to both national and international standards for human and ecological use. The results indicated that the water quality levels exceeded the guideline values of national and international standards for the following uses: drinking water, certain industrial activities, watering of certain livestock and crop types as well as aquaculture. It was also found that the water quality was acceptable for certain activities (e.g. recreation) only if precautions and further analysis are performed. The guideline values of national water quality standards for ecological status were also exceeded, while the PAI results indicated that the ecological category (EC) for the Wonderfonteinspruit is a D which indicates that the state of the water quality in terms of the ecology is fair. The sediment quality of the Wonderfonteinspruit was determined by ICP-MS. The metal composition of the sediment was compared to that of other rivers and the following indices were applied: enrichment factor (EF), contamination factor (CF), pollution load index (PLI) and geo-accumulation index (Igeo). It was found that the sediment composition is comparable to that of other rivers impacted by gold mining and that uranium, cobalt and nickel enriched the sediment according to the indices. Biotic indicators that were assessed included fish, diatoms and invertebrates. The fish health assessment index (HAI) was applied to fish caught in the Donaldson Dam. The muscle tissue was also removed and its metal concentration was determined by ICP-MS. Thereafter, the edibility of the fish muscle tissue was determined and the following indices were applied: condition factor (CF), hepatosomatic index (HSI), gonadosomatic index (GSI) and spleen somatic index (SSI). The diatom community composition was assessed by applying the Biological Diatom Index (BDI), Specific Pollution Sensitivity Index (SPI) and the percentage pollution tolerant valves (%PTV). The Macroinvertebrate Response Assessment Index (MIRAI) was applied in order to determine the state of the macroinvertebrate community. The fish assessment indicated that arsenic contamination may negatively impact the health of consumers. Diatom indices indicated that the EC of the Wonderfonteinspruit is a D/E which indicates poor water quality; likewise, this is supported by the MIRAI results as the EC for MIRAI was a D which indicates that the river is largely modified. The investigation into the water use of the Bekkersdal community, with a special focus on the use of the Wonderfonteinspruit, was achieved through the use of questionnaires that were distributed in both formal and informal sections in Bekkersdal. The research forms part of a larger Integrative Multidisciplinary study and was given ethical clearance under the NRF Community Engagement Project (see Ethical Clearance: no. FH-BE-2013-0014. The National Research Fund (NRF) provided the funding for the research, the views expressed is that of the author and not those of the NRF. The aim of the questionnaire was to determine the following aspects in terms of the community of Bekkersdal: - Demographic details, such as language preference, employment status and age distribution. - Current water use practices . - Use of the Wonderfonteinspruit. - Future water use of the Wonderfonteinspruit. - Water quality perceptions of the Wonderfonteinspruit. - Field notes that included any relevant observations of the fieldworkers. The unemployment rate of the Bekkersdal community was found to be high (78.20%) and 86.40% of the residents are South African citizens. The community relies heavily on municipal provision of sources of water with 100% of the respondents indicating that it is their primary source of water. However, several issues were identified in terms of municipal water supply in the community. Some 10.14% of the residents indicated that they make regular use of the Wonderfonteinspruit (in particular the Donaldson Dam) most often for drinking water, laundry and washing of cars, etc. Regarding the state of the Wonderfonteinspruit, the overall viewpoint of the Bekkersdal community was that it is largely polluted with sewage, litter and mining waste. However, some 87.80% of the residents expressed their willingness to participate in environmental clean-up initiatives in their area. The link between the ecological state of the Wonderfonteinspruit and human health and wellbeing was explored through the use of spider diagrams where rank scores were assigned to both index results and human water quality use categories. These were compared and it was found that ecological indicators are more sensitive than human water quality use scores and therefore can aid in acting as early detection indicators of possible negative impacts on human health and wellbeing. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

In order for an economy to survive and thrive it requires resources. Water is a resource that not only the economy is dependent on but also ecological and human communities. The deteriorated state of South African rivers suggests the intensive use of the country’s freshwater reserves by the population and industry. Such a source of freshwater is the Wonderfonteinspruit. It flows through an area that requires water for gold mining that has taken place in the area for more than 120 years. Furthermore, the Wonderfonteinspruit runs past communities such as Bekkersdal and eventually forms part of the source waters for the Boskop Dam, the main drinking water reservoir for Potchefstroom. Literature suggests that the Wonderfonteinspruit is impacted by anthropogenic activities, in particular impacts associated with both historical and current gold mining activities. The Wonderfonteinspruit has its origin in the Tudor Dam in Krugersdorp (now Mogale City), and then flows into Donaldson Dam from where it is piped in a 32 km long pipeline, before its confluence with the Mooi River which subsequently flows into the Boskop Dam. The study area specifically focuses on the Upper Wonderfonteinspruit from just downstream of the Donaldson Dam to just upstream of the dam. The study area was selected due to the close proximity of the Donaldson Dam to the community of Bekkersdal which formed the second part of the investigation for this thesis. Bekkersdal is primarily a mining community that has historically faced issues with sufficient land provision, housing, unemployment and service delivery. It is located in the Gauteng Province and falls under the jurisdiction of Westonaria Local Municipality. Recent protests by community members have occurred due to the lack of service delivery and inappropriate development of infrastructure with regards to water services. Due to the close proximity of Bekkersdal to the Wonderfonteinspruit (as it is situated on the border of the Donaldson Dam) the community provided an ideal study area to explore the use of the river by the community. In order to determine the relationship between the Wonderfonteinspruit and the community of Bekkersdal the study comprised two parts: during the first part of the study, the ecological state of the Wonderfonteinspruit was determined through the evaluation of the quality of water, sediment and biota within the river; while in the second part an assessment of Bekkersdal (both formal and informal sections) was undertaken through the use of questionnaires in order to determine past, current and future water use of both municipal water and water sourced from the Wonderfonteinspruit. The final outcomes of both the environmental and social assessments were then compared with national and international standards. Water quality assessment of the Wonderfonteinspruit was done by assessing the following: - in situ water quality parameters (such as pH, total dissolved solids and dissolved oxygen) - metal and ionic composition analysis of water samples using inductively coupled plasma mass spectrophotometry (ICP-MS) - nutrient loads using a spectrophotometer and Spectroquant® test kits - bacteriological quality by determining presence of total coliforms and faecal coliforms through the growth of bacterial cultures on M-ENDO and m-FC agar plates - the Physico-chemical Driver Assessment Index (PAI) was applied according to DWAF 2008 - statistical relevance between sites and results through principal component analysis (PCA) Finally, these results, where applicable, were compared to both national and international standards for human and ecological use. The results indicated that the water quality levels exceeded the guideline values of national and international standards for the following uses: drinking water, certain industrial activities, watering of certain livestock and crop types as well as aquaculture. It was also found that the water quality was acceptable for certain activities (e.g. recreation) only if precautions and further analysis are performed. The guideline values of national water quality standards for ecological status were also exceeded, while the PAI results indicated that the ecological category (EC) for the Wonderfonteinspruit is a D which indicates that the state of the water quality in terms of the ecology is fair. The sediment quality of the Wonderfonteinspruit was determined by ICP-MS. The metal composition of the sediment was compared to that of other rivers and the following indices were applied: enrichment factor (EF), contamination factor (CF), pollution load index (PLI) and geo-accumulation index (Igeo). It was found that the sediment composition is comparable to that of other rivers impacted by gold mining and that uranium, cobalt and nickel enriched the sediment according to the indices. Biotic indicators that were assessed included fish, diatoms and invertebrates. The fish health assessment index (HAI) was applied to fish caught in the Donaldson Dam. The muscle tissue was also removed and its metal concentration was determined by ICP-MS. Thereafter, the edibility of the fish muscle tissue was determined and the following indices were applied: condition factor (CF), hepatosomatic index (HSI), gonadosomatic index (GSI) and spleen somatic index (SSI). The diatom community composition was assessed by applying the Biological Diatom Index (BDI), Specific Pollution Sensitivity Index (SPI) and the percentage pollution tolerant valves (%PTV). The Macroinvertebrate Response Assessment Index (MIRAI) was applied in order to determine the state of the macroinvertebrate community. The fish assessment indicated that arsenic contamination may negatively impact the health of consumers. Diatom indices indicated that the EC of the Wonderfonteinspruit is a D/E which indicates poor water quality; likewise, this is supported by the MIRAI results as the EC for MIRAI was a D which indicates that the river is largely modified. The investigation into the water use of the Bekkersdal community, with a special focus on the use of the Wonderfonteinspruit, was achieved through the use of questionnaires that were distributed in both formal and informal sections in Bekkersdal. The research forms part of a larger Integrative Multidisciplinary study and was given ethical clearance under the NRF Community Engagement Project (see Ethical Clearance: no. FH-BE-2013-0014. The National Research Fund (NRF) provided the funding for the research, the views expressed is that of the author and not those of the NRF. The aim of the questionnaire was to determine the following aspects in terms of the community of Bekkersdal: - Demographic details, such as language preference, employment status and age distribution. - Current water use practices . - Use of the Wonderfonteinspruit. - Future water use of the Wonderfonteinspruit. - Water quality perceptions of the Wonderfonteinspruit. - Field notes that included any relevant observations of the fieldworkers. The unemployment rate of the Bekkersdal community was found to be high (78.20%) and 86.40% of the residents are South African citizens. The community relies heavily on municipal provision of sources of water with 100% of the respondents indicating that it is their primary source of water. However, several issues were identified in terms of municipal water supply in the community. Some 10.14% of the residents indicated that they make regular use of the Wonderfonteinspruit (in particular the Donaldson Dam) most often for drinking water, laundry and washing of cars, etc. Regarding the state of the Wonderfonteinspruit, the overall viewpoint of the Bekkersdal community was that it is largely polluted with sewage, litter and mining waste. However, some 87.80% of the residents expressed their willingness to participate in environmental clean-up initiatives in their area. The link between the ecological state of the Wonderfonteinspruit and human health and wellbeing was explored through the use of spider diagrams where rank scores were assigned to both index results and human water quality use categories. These were compared and it was found that ecological indicators are more sensitive than human water quality use scores and therefore can aid in acting as early detection indicators of possible negative impacts on human health and wellbeing. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Les réseaux sociaux sont de plus en plus utilisés en écologie pour représenter et analyser la structure sociale. Modéliser la structure sociale permet de mieux comprendre les processus de transmission des maladies et de l’information entre les individus, ainsi que les bénéfices de la socialité sur la valeur adaptative des individus. Jusqu’à maintenant peu d’études ont identifié les déterminants et les conséquences des associations sociales. De surcroît, on connaît peu sur l’influence du type de données comportementales et du choix de l’indice d’association sur la structure des réseaux sociaux. Ma maîtrise explore les déterminants et conséquences de la socialité de même que l’impact du type de données pour la construction de réseaux sociaux grâce à la disponibilité de différents types de données comportementales et au suivi à long terme de la population de mouflons d’Amérique (Ovis canadensis) à Ram Mountain en Alberta. J’ai comparé trois réseaux sociaux construits avec trois types de données comportementales: co-occurrence dans un groupe, fréquence de proximité à ≤ 1,5 mètre et interactions agonistiques pour quantifier dans quelle mesure ces trois réseaux représentant la structure sociale des brebis adultes étaient similaires. Pour ce faire, j’ai contrasté des mesures individuelles et de réseaux. L’approche fréquemment utilisée d’utiliser les groupes pour inférer les associations sociales se révèle imparfaite: à l’intérieur d’un groupe, les associations sociales ne sont pas égales entre tous les membres. Ce travail souligne l’importance de choisir le type de données qui permet de répondre aux questions biologiques d’intérêt. Or, il semble que pour la population étudiée, les réseaux construits avec la composition de groupe et avec les évènements de proximité soient pertinents dans des contextes différents. Par conséquent, j’ai utilisé les évènements de proximité qui font appel à une association à fine échelle pour identifier les déterminants des associations entre les dyades. Pour une dyade, il y a un effet positif de la similarité du statut reproducteur sur la fréquence des associations pour les années 2011 et 2012. L’apparentement, la similarité en âge ou en rang de dominance n’influence pas la fréquence d’association d’une dyade. Quant au niveau de sociabilité à l’échelle individuelle, les brebis plus jeunes sont les plus centrales dans les réseaux sociaux et donc les plus sociables. Mes travaux de maîtrise amènent un nouveau regard sur l’étude de la socialité chez les animaux grâce à l’utilisation de réseaux sociaux pour explorer les déterminants et conséquences des associations sociales.

The present power system is loaded with sophisticated energy conversion technologies like solid state converters. With the rapid advance in semiconductor technology, power electronics have provided new devices that are highly efficient and reliable. These devices are inherently non-linear, which causes the current to deviate from sinusoidal conditions. This phenomenon is known as harmonic current distortion. Multiple consumers are connected to the utility at the point of common coupling. Harmonic currents are then transmitted into the distribution system by various solid state users and this could lead to voltage distortion. Harmonic distortion is just one of the power quality fields and is not desirable in a power system. Distortion levels could cause multiple problems in the form of additional heating, increased power losses and even failing of sensitive equipment. Utility companies like Eskom have power quality monitors on various points in their distribution system. Data measurements are taken at a single point of delivery during certain time intervals and stored on a database. Multiple harmonic measurements will not be able to describe distortion patterns of the whole distribution system. Analysis must be done on this information to translate it to useful managerial information. The aim of this project is to develop a benchmarking methodology that could aid the supply industry with useful information to effectively manage harmonic distortion in a distribution system. The methodology will implement distortion indexes set forth by the Electrical Power Research Institute [3], which will describe distortion levels in a qualitative and quantitative way. Harmonic measurements of the past two years will be used to test the methodology. The information is obtained from Eskom’s database and will benchmark the North-West Province distribution network [40]. This proposed methodology will aim to aid institutions like NERSA to establish a reliable power quality management system. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2012

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Southern Louisiana is experiencing a dramatic loss of freshwater wetlands as a result of natural and man-made changes in the landscape. Multitempral remotely sensed data were used to examine the impact of the Caernarvon Freshwater Diversion Structure, built in 1991 to divert water to Breton Sound. Satellite imagery data covering the period from 1974 to 2006 were analyzed by computing several spectral indices including NDVI, VI, IR/R, Sqrt IR/R, T-NDVI, and NDWI, as well as principle component analysis. The resulting enhanced images were classified into two classes, vegetation or open water. The ratios of vegetation to open water were then calculated and the changes graphed over the 1974-2006 timeframe. The results indicated that despite the infusion of freshwater, the open water portion of the Breton Sound area continued to expand, indeed the expansion rate increased from approximately 0.25% per year before construction of Caernarvon to 0.45% per year after construction.

Student Number : 0310612G - MSc research report - School of Geography, Archaeology and Environmental Studies - Faculty of Science / Wildfire prediction and management is an issue of safety and security for many rural communities in South Africa. Wildfire prediction and early warning systems can assist in saving lives, infrastructure and valuable resources in these communities. Timely and accurate data are required for accurate wildfire prediction on both weather conditions and the availability of fuels (vegetation) for wildfires. Wildfires take place in large remote areas in which land use practices and alterations to land cover cannot easily be modelled. Remote sensing offers the opportunity to monitor the extent and changes of land use practices and land cover in these areas. In order for effective fire prediction and management, data on the quantity and state of fuels is required. Traditional methods for detecting vegetation rely on the chlorophyll content and moisture of vegetation for vegetation mapping techniques. Fuels that burn in wildfires are however predominantly dry, and by implication are low in chlorophyll and moisture contents. As a result, these fuels cannot be detected using traditional indices. Other model based methods for determining above ground vegetation biomass using satellite data have been devised. These however require ancillary data, which are unavailable in many rural areas in South Africa. A method is therefore required for the detection and quantification of dry fuels that pose a fire risk. ASTER and MAS (MODIS Airborne Simulator) imagery were obtained for a study area within the Lowveld region of the Limpopo Province, South Africa. Two of the ASTER and two of the MAS images were dated towards the end of the dry season (winter) when the quantity of fuel (dry vegetation) is at its highest. The remaining ASTER image was obtained during the middle of the wet season (summer), against which the results could be tested. In situ measurements of above ground biomass were obtained from a large number of collection points within the image footprints. Normalised Difference Vegetation Index and Transformed Vegetation Index vegetation indices were calculated and tested against the above ground biomass for the dry and wet season images. Spectral response signatures of dry vegetation were evaluated to select wavelengths, which may be effective at detecting dry vegetation as opposed to green vegetation. Ratios were calculated using the respective bandwidths of the ASTER and MAS sensors and tested against above ground biomass to detect dry vegetation. The findings of this study are that it is not feasible, using ASTER and MAS remote sensing data, to estimate brown and green vegetation biomass for wildfire prediction purposes using the datasets and research methodology applied in this study. Correlations between traditional vegetation indices and above ground biomass were weak. Visual trends were noted, however no conclusive evidence could be established from this relationship. The dry vegetation ratios indicated a weak correlation between the values. The removal of background noise, in particular soil reflectance, may result in more effective detection of dry vegetation. Time series analysis of the green vegetation indices might prove a more effective predictor of biomass fuel loads. The issues preventing the frequent and quick transmission of the large data sets required are being solved with the improvements in internet connectivity to many remote areas and will probably be a more viable path to solving this problem in the near future.

O Brasil é um dos países mais ricos em água doce, mas também repleto de problemas relacionados à qualidade de suas águas, prejudicando a disponibilidade necessária para os seus múltiplos usos. O quadro de degradação da qualidade dos corpos hídricos brasileiros gerou a necessidade do estabelecimento de medidas que assegurassem a sustentabilidade destes usos e o enquadramento é considerado uma das ferramentas estratégicas para esta garantia, porque por meio desta é possível o estabelecimento de metas de qualidade da água, as quais devem ser alcançadas ou mantidas no corpo hídrico ao longo do tempo. A Política Nacional de Recursos Hídricos (Lei n. 9.433/1997) define o enquadramento como um de seus instrumentos para a gestão integrada da qualidade e quantidade da água e a Resolução CONAMA n.357/2005 classifica os corpos hídricos brasileiros segundo os seus usos preponderantes e define padrões de qualidade que devem ser obedecidos para a garantia da sustentabilidade hídrica. O acompanhamento da situação de enquadramento precisa ser encarado como uma atividade essencial para o planejamento de uma bacia hidrográfica e para auxiliar os gestores de recursos hídricos nos processos decisórios. Este trabalho apresenta o estudo de um índice capaz de informar de forma clara e objetiva a situação do corpo hídrico em relação à meta de qualidade da água proposta. O índice está baseado no IQA desenvolvido pelo Canadian Council of Ministers of the Environmental no Canadá, é um método fundamentado na excedência de padrões de qualidade da água previamente definidos, apropriado para o caso brasileiro, pois permite além da avaliação, a inclusão de novas variáveis e padrões de qualidade da água para os diversos usos hídricos. Os resultados obtidos são capazes de mostrar o comportamento dos rios estudados ao longo do tempo em relação a sua condição hídrica, permitindo a localização dos pontos da bacia que precisam de medidas para atender aos padrões estabelecidos pela Resolução CONAMA n.357. / Brazil is one of the richest countries in freshwater, but also full of problems related to the quality of the water, impairing the availability required for its multiple uses. The picture of degradation of the quality of water bodies has led Brazil to the need of establishing measures to ensure the sustainability of these uses and the framing is considered one of the strategic tools for this guarantee, with the establishment of water quality objectives, which must be achieved or kept in the water body over time. The National Water Resources Policy (Law n. 9.433/1997) establishes the framing as one of its instruments for integrated management of water quality and quantity and Resolution CONAMA n.357/2005 classifies the Brazilian water bodies according to their predominant uses and defines quality standards that must be obeyed to guarantee sustainability of the water. Monitoring the situation of environment must be seen as an essential activity to the planning of a watershed and to facilitate the decision-making process in the water resources management. This paper presents the initial study of an index able to report clearly and objectively the situation of the water body in relation to the goal of water quality proposal. The index is based on the Water Quality Index (WQI) developed by the Canadian Council of Ministers of the Environmental Canada, is a method based on exceedance of water quality standards previously defined, appropriate for the Brazilian case, it allows also the evaluation, the inclusion of new variables and water quality objectives for various water uses. The results are able to show the behavior of the rivers studied over time in relation to their water condition and identifies critical areas of the watershed in need of additional pollution control practices to achieve the desired water quality standards by CONAMA n.357 Resolution.