No description available.

No description available.

Transmission of video content over wireless access networks (in particular, Wireless Local Area Networks (WLAN) and Third Generation Universal Mobile Telecommunication System (3G UMTS)) is growing exponentially and gaining popularity, and is predicted to expose new revenue streams for mobile network operators. However, the success of these video applications over wireless access networks very much depend on meeting the user’s Quality of Service (QoS) requirements. Thus, it is highly desirable to be able to predict and, if appropriate, to control video quality to meet user’s QoS requirements. Video quality is affected by distortions caused by the encoder and the wireless access network. The impact of these distortions is content dependent, but this feature has not been widely used in existing video quality prediction models. The main aim of the project is the development of novel and efficient models for video quality prediction in a non-intrusive way for low bitrate and resolution videos and to demonstrate their application in QoS-driven adaptation schemes for mobile video streaming applications. This led to five main contributions of the thesis as follows:(1) A thorough understanding of the relationships between video quality, wireless access network (UMTS and WLAN) parameters (e.g. packet/block loss, mean burst length and link bandwidth), encoder parameters (e.g. sender bitrate, frame rate) and content type is provided. An understanding of the relationships and interactions between them and their impact on video quality is important as it provides a basis for the development of non-intrusive video quality prediction models.(2) A new content classification method was proposed based on statistical tools as content type was found to be the most important parameter. (3) Efficient regression-based and artificial neural network-based learning models were developed for video quality prediction over WLAN and UMTS access networks. The models are light weight (can be implemented in real time monitoring), provide a measure for user perceived quality, without time consuming subjective tests. The models have potential applications in several other areas, including QoS control and optimization in network planning and content provisioning for network/service providers.(4) The applications of the proposed regression-based models were investigated in (i) optimization of content provisioning and network resource utilization and (ii) A new fuzzy sender bitrate adaptation scheme was presented at the sender side over WLAN and UMTS access networks. (5) Finally, Internet-based subjective tests that captured distortions caused by the encoder and the wireless access network for different types of contents were designed. The database of subjective results has been made available to research community as there is a lack of subjective video quality assessment databases.

The National Water Act (Act 36 of 1998) provides for an ecological Reserve as the quantity (flow) and quality of water needed to protect aquatic ecosystems. While there are methods available to quantify the ecological Reserve in terms of flow, methods of linking flow to water quality are lacking. Therefore, the research presented in this thesis investigated various modelling techniques to estimate the effect of flow on water quality. The aims of the research presented in this thesis were: Aim 1: Can the relationship between flow and water quality be accurately represented by simple statistical models? Aim 2: Can relatively simple models accurately represent the relationship between flow and water quality? Aim 3: Can the effect of diffuse sources be omitted from a water quality model and still obtain realistic simulations, and if so under what conditions? Aim 4: Can models that solely use historical monitoring data, accurately represent the relationships between flow and water quality? In Chapter 3, simple Q-C regressions of flow and water quality were investigated using Department of Water Affairs (DWA) historical monitoring data. It was found that while flow versus salinity regressions gave good regression fits in many cases, the Q-C regression approach is limited. A mechanistic/statistical model that attempted to estimate the point and diffuse signatures of nutrients in response to flow was developed in Chapter 4 using DWA historical monitoring data. The model was verified as accurate in certain case studies using observed point loading information. In Chapter 5, statistical models that link land cover information to diffuse nutrient signatures in response to flow using DWA historical data were developed. While the model estimations are uncertain due to a lack of data, they do provide an estimation of the diffuse signature within catchments where there is flow and land cover information available. Chapter 6 investigates the extension of an existing mass-balance salinity model to estimate the effect of saline irrigation return flow on in-stream salinity. The model gave accurate salinity estimates for a low order stream with little or no irrigation within its catchment, and for a permanently flowing river within a catchment used extensively for irrigation. Chapter 7 investigated a modelling method to estimate the reaction coefficients involved in nitrification using only DWA historical monitoring data. Here, the model used flow information to estimate the residence time of nutrients within the studied river reaches. While the model obtained good estimations of nitrification for the data it was applied to, very few DWA data sets were suitable for the model. Chapter 8 investigated the ability of the in-stream model QUAL2K to estimate nutrient concentrations downstream of point and diffuse inputs of nutrients. It was found that the QUAL2K model can give accurate results in cases where point sources dominate the total nutrient inputs into a river. However, the QUAL2K simulations are too uncertain in cases where there are large diffuse source inputs of nutrients as the load of the diffuse inputs is difficult to measure in the field. This research highlights the problem of data scarcity in terms of temporal resolution as well as the range of constituents measured within DWA historical monitoring data for water quality. This thesis in addition argues that the approach of applying a number of models is preferable to applying one model to investigate the research aims, as particular models would be suited to particular circumstances, and the development of new models allowed the research aims of this thesis to be explored more thoroughly. It is also argued that simpler models that simulate a few key processes that explain the variation in observed data, are more suitable for implementing Integrated Water Resource Management (IWRM) than large comprehensive water quality models. From this research, it is clear that simple statistical models are not adequate for modelling the relationship between flow and water quality, however, relatively simple mechanistic models that simulate a limited number of processes and water quality variables, can provide accurate representations of this relationship. Under conditions where diffuse sources are not a major factor within a catchment, models that omit diffuse sources can obtain realistic simulations of the relationship between flow and water quality. Most of the models investigated in this thesis demonstrate that accurate simulations of the relationships between flow and water quality can be obtained using solely historical monitoring data.

One of the most important purposes of surface water resource management is to develop predictive models to assist in identifying and evaluating operational and structural measures for improving water quality. To better understand the effects of external and internal nutrient and organic loading and the effects of reservoir operation, a model is often developed, calibrated, and used for sensitivity and management simulations. The importance of modeling and simulation in the scientific community has drawn interest towards methods for automated calibration. This study addresses using an automatic technique to calibrate the water quality model CE-QUAL-W2 (Cole and Wells, 2013). CE-QUAL-W2 is a two-dimensional (2D) longitudinal/vertical hydrodynamic and water quality model for surface water bodies, modeling eutrophication processes such as temperature-nutrient-algae-dissolved oxygen-organic matter and sediment relationships. The numerical method used for calibration in this study is the particle swarm optimization method developed by Kennedy and Eberhart (1995) and inspired by the paradigm of birds flocking. The objective of this calibration procedure is to choose model parameters and coefficients affecting temperature, chlorophyll a, dissolved oxygen, and nutrients (such as NH4, NO3, and PO4). A case study is presented for the Karkheh Reservoir in Iran with a capacity of more than 5 billion cubic meters that is the largest dam in Iran with both agricultural and drinking water usages. This algorithm is shown to perform very well for determining model parameters for the reservoir water quality and hydrodynamic model. Implications of the use of this procedure for other water quality models are also shown.

No description available.

Acid-base equilibria in organic particulate matter (PM) are poorly understood, but have important implications for air quality and public health. First, acid-base reactions in organic particulate matter affect the gas/particle partitioning of organic compounds in the atmosphere, and these processes are not currently represented in atmospheric and climate change models. Second, the acid-base balance of tobacco smoke affects the amount of nicotine absorbed by the smoker, and a greater understanding of this balance would help to relate cigarette smoke composition to the addictive properties of cigarettes. This work presents data related to both air quality and tobacco smoke modeling. The gas/particle partitioning behavior of organic acids and bases is highly dependent on acid-base equilibria and speciation between neutral and ionic forms, because ionic compounds do not volatilize. Descriptions of acid dissociation behavior in atmospheric PM have, to date, focused primarily on phases in which the solvent is water; however, atmospheric PM may include up to 90% organic matter. Data is presented here describing the acid dissociation behavior of organic acids and protonated amines in organic/aqueous mixtures (chosen to approximate the characteristics of organic PM) with varying levels of water content. In such mixtures, the preferential solvation of ions and neutral molecules (by the aqueous portion or the organic portion, respectively) affects the acid-base equilibria of the solutes. It is demonstrated that neutralization reactions between acids and bases that create ions are likely to have non-negligible effects on gas/particle partitioning under certain atmospheric conditions. Thus, including acid-base reactions in organic gas/particle partitioning models could result in a greater proportion of acidic and basic compounds partitioning to the particulate phase. In addition, the acid dissociation constants (pKa values) of atmospherically-relevant acids and bases vary with water content. Specifically, as water content increases, the pKa values of organic acids decrease dramatically, while the pKa values of protonated amines changes only slightly. This situation can result in drastically different speciations and partitioning behavior depending on water content. This second part of this work reports some of the data needed to develop an acid-base balance for tobacco smoke PM using electroneutrality as a governing principle. Five brands of cigarettes were sampled and the smoke PM extracted. Cations (sodium, potassium, and ammonia) and anions (organic acids, nitrate, nitrite, and chloride) were measured using ion chromatography. Ammonia and organic acids were also re-measured after the acidification of the sample in order to determine whether "bound" forms of these compounds exist in cigarette PM. Weak acids were determined by acid-base titration to determine whether or not all of the weak acids (including organic acids) had been accounted for by the ion chromatography. Weak bases were also determined by acid-base titration, and the majority of weak base is expected to be accounted for by total nicotine (to be measured in a separate analysis). In terms of total acidic species and total basic species, two of the five cigarette brands measured were relatively basic, and three were relatively acidic. Between 50% and 89% of the titrated acids were accounted for by the anionic species measured in ion chromatography. Based on samples tested after sample acidification, about half of the potential ammonia in tobacco smoke PM exists in "bound" form. The speciation of weak acids and bases in tobacco smoke PM cannot be determined from this data alone, because the equilibrium constants of acid-base reactions are not understood in complex organic media. The data presented here, when combined with data from free-base and total nicotine analyses, represent a first step toward a predictive model of acid-base behavior in tobacco smoke PM.

O objetivo desta pesquisa foi avaliar a qualidade dos serviços públicos eletrônicos sob a ótica dos gestores públicos e dos usuários. Para realizar tal pesquisa foram realizadas entrevistas em profundidade com os gestores públicos da cidade de Ribeirão Preto e da cidade de Vinhedo. E também, foram aplicados questionários em sua forma on line para avaliar a satisfação dos usuários em relação ao site municipal (cidade de Ribeirão Preto) e o site estadual (site do Programa Poupatempo). Os resultados obtidos na pesquisa foram que os itens relacionados à facilidade de uso do site, oferecimento do que era esperado, fornecimento das informações com qualidade e o estímulo do site ao uso repetido foram os fatores melhor avaliados pelos usuários na cidade de Ribeirão Preto. E na cidade de Vinhedo, os itens que foram melhores avaliados foram: o fornecimento das informações com qualidade, o estímulo do site ao uso repetido e o oferecimento do que era esperado. Tais resultados implicam que apesar das diferenças existentes entre as cidades, os itens relacionados à satisfação dos usuários foram praticamente os mesmos. Logo, esta pesquisa contribuiu para auxiliar os gestores públicos municipais a nortear as suas ações para melhoria da qualidade dos serviços públicos oferecidos. A pesquisa revelou a necessidade de uma efetiva coordenação por parte de órgãos federais no sentido de facilitar o desenvolvimento dos serviços de governo eletrônico. Pesquisas futuras nesta área poderiam replicar o questionário e as entrevistas aplicadas visando corroborar os elementos identificados em outras esferas governamentais. / The objective of this research was to evaluate the quality of the electronics from the perspective of public managers and users of public services. To conduct such research indepth interviews were conducted with public officials of the city of Ribeirão Preto and the town of Vinhedo. Also, questionnaires were administered in form online to evaluate user satisfaction in relation to the municipal website (Ribeirão Preto) and state site (the site Poupatempo Program). The results obtained in the study were that items related to ease of use of the site, offering what was expected, provision of quality information and encouragement to the repeated use of the site were the best factors evaluated by the users in the city of Ribeirão Preto. And in the town of Vinhedo, items that were best were: the provision of quality information, the stimulus site to repeated use and delivery than expected. These results imply that despite the differences between the cities, the items related to user satisfaction were almost the same. Therefore, this research has contributed to assist the municipal administrators to govern its actions to improve the quality of public services. The survey revealed the need for effective coordination by federal agencies to facilitate the development of electronic government services. Future research in this area could replicate the questionnaire and the interviews applied aiming to corroborate the elements identified in other spheres of government.

Historical water quality databases from two South Australian drinking water reservoirs were used, in conjunction with various computational modelling methods for the ordination, clustering and forecasting of complex ecological data. Techniques used throughout the study were: Kohonen artificial neural networks (KANN) for data categorisation and the discovery of patterns and relationships, recurrent supervised artificial neural networks (RANN) for knowledge discovery and forecasting of algal dynamics and hybrid evolutionary algorithms (HEA) for rule-set discovery and optimisation for forecasting algal dynamics. These methods were combined to provide an integrated approach to the analysis of algal populations including interactions within the algal community and with other water quality factors, which results in improved understanding and forecasting of algal dynamics. The project initially focussed on KANN for the patternising and classification of the historical data to reveal links between the physical, chemical and biological components of the reservoirs. This offered some understanding of the system and relationships being considered for the construction of the forecasting models. Specific investigations were performed to examine past conditions and the impacts of different management regimes, as well as to discover sets of conditions that correspond with specific algal functional groups. RANN was then used to build models for forecasting both Chl-a and the main nuisance species, Anabaena, up to 7 days in advance. This method also provided sensitivity analyses to demonstrate the relationship between input and output variables by plotting the reaction of the output to variations in the inputs. Initially one year from the data set was selected for the testing of a model, as per the split-sample technique. To further test the models, it was later decided to select several years for testing to ensure the models were useful under changed conditions, and that test results were not misleading regarding the models true capabilities. RANN were firstly used to create reservoir specific or ad-hoc models. Later, the models were trained with the merged data sets of both reservoirs to create one model that could be applied to either reservoir. Another method of forecasting was trialled and compared to RANN. HEA was found to be equal or superior to RANN in predictive power, also allowed sensitivity analysis and provided an explicit, portable rule set. The HEA rule sets were initially tested on selected years of data, however to fully demonstrate the models potential, a process for k-fold cross-validation was developed to test the rule-set on all years of data. To further extend the applicability of the HEA rule-set; the idea of rule-based agents for specific lake ecosystem categories was examined. The generality of a rule-based agent means that, after successful validation on several lakes from one category, the agent could then be applied to other water bodies from within that category that had not been involved in the training process. The ultimate test of the rule-based agent for the warm monomictic and eutrophic lake ecosystem category was to be applied to a real-time monitoring and forecasting situation. The agent was fed with online, real-time data from a reservoir that belonged to the same ecosystem category but was not used in the training process. These preliminary experiments showed promising results. It can be concluded that the concept of rulebased agents will facilitate real-time forecasting of algal blooms in drinking water reservoirs provided on-line monitoring of relevant variables has been implemented. Contributions of this research include: (1) to offer insight into the capabilities of 3 kinds of computational modelling techniques applied to complex water quality data, (2) novel applications of KANN including the division of data into separate management periods for comparison of management efficiency, (3) to both qualitatively and quantitatively elucidate relationships between water quality parameters, (4) research toward the development of a forecasting tool for algal abundance 7 days in advance that could be generic for a particular lake ecosystem category and implemented in real-time, and (5) to suggest a thorough testing method for such models (k-fold cross validation). / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1331584 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

O objetivo desta pesquisa foi avaliar a qualidade dos serviços públicos eletrônicos sob a ótica dos gestores públicos e dos usuários. Para realizar tal pesquisa foram realizadas entrevistas em profundidade com os gestores públicos da cidade de Ribeirão Preto e da cidade de Vinhedo. E também, foram aplicados questionários em sua forma on line para avaliar a satisfação dos usuários em relação ao site municipal (cidade de Ribeirão Preto) e o site estadual (site do Programa Poupatempo). Os resultados obtidos na pesquisa foram que os itens relacionados à facilidade de uso do site, oferecimento do que era esperado, fornecimento das informações com qualidade e o estímulo do site ao uso repetido foram os fatores melhor avaliados pelos usuários na cidade de Ribeirão Preto. E na cidade de Vinhedo, os itens que foram melhores avaliados foram: o fornecimento das informações com qualidade, o estímulo do site ao uso repetido e o oferecimento do que era esperado. Tais resultados implicam que apesar das diferenças existentes entre as cidades, os itens relacionados à satisfação dos usuários foram praticamente os mesmos. Logo, esta pesquisa contribuiu para auxiliar os gestores públicos municipais a nortear as suas ações para melhoria da qualidade dos serviços públicos oferecidos. A pesquisa revelou a necessidade de uma efetiva coordenação por parte de órgãos federais no sentido de facilitar o desenvolvimento dos serviços de governo eletrônico. Pesquisas futuras nesta área poderiam replicar o questionário e as entrevistas aplicadas visando corroborar os elementos identificados em outras esferas governamentais. / The objective of this research was to evaluate the quality of the electronics from the perspective of public managers and users of public services. To conduct such research indepth interviews were conducted with public officials of the city of Ribeirão Preto and the town of Vinhedo. Also, questionnaires were administered in form online to evaluate user satisfaction in relation to the municipal website (Ribeirão Preto) and state site (the site Poupatempo Program). The results obtained in the study were that items related to ease of use of the site, offering what was expected, provision of quality information and encouragement to the repeated use of the site were the best factors evaluated by the users in the city of Ribeirão Preto. And in the town of Vinhedo, items that were best were: the provision of quality information, the stimulus site to repeated use and delivery than expected. These results imply that despite the differences between the cities, the items related to user satisfaction were almost the same. Therefore, this research has contributed to assist the municipal administrators to govern its actions to improve the quality of public services. The survey revealed the need for effective coordination by federal agencies to facilitate the development of electronic government services. Future research in this area could replicate the questionnaire and the interviews applied aiming to corroborate the elements identified in other spheres of government.