Environmental management has increasingly become a participatory process. In recent times, emphasis has been placed on watershed-based solutions to remediate the problems of diffuse source pollution and to engage stakeholders in designing solutions. Water quality models are an integral part of this process; such models are often inaccessible to lay stakeholders. A review of the literature suggests that properly applied partnerships have several benefits that go beyond decision-making. Stakeholder education and enhancements to the eventual outcome from stakeholder insight and support are two such benefits. To aid engineers and scientists, who often do not interact directly with other stakeholders, several best practices were identified that may be applied to develop, manage, and evaluate stakeholder partnerships. Environmental Decision Support Systems (EDSSs) have been shown to be an effective way to promote stakeholder partnerships in environmental decision-making. Many current EDSSs were designed to be used by experts, thus limiting their effectiveness for stakeholder engagement. Often, these EDSSs, if designed for lay stakeholders, were not coupled with water quality models. To demonstrate that complex water quality models may be made accessible to stakeholders, without any significant changes to the modeling scheme, a web-based EDSS was developed for the Occoquan Reservoir, located in northern Virginia, U.S.A., and its tributary watershed. The developed EDSS may also be readily extended to other watersheds and their modeling programs. The current implementation of the EDSS enables users to modify land use and analyze simulated changes to water quality due to these modifications. A local-network server cluster, based on the Locally Distributed Simultaneous Model Execution (LDSME) framework, was also developed and served as a backend to the EDSS. The server cluster can support simultaneous execution of multiple water quality models or any other software on disparate computers. This system was employed to study pre-development and other land use modification scenarios in the Occoquan Watershed. The pre-development scenario offers an easy-to-understand and universally-applicable baseline for measuring waterbody and watershed restoration progress. It enabled computation of a measure called the "developed-excess," which is independent of local conditions and may be used for comparisons among various watershed sub-divisions or between watersheds. / Ph. D.

No contexto da disponibilidade hídrica comprometida pela poluição de mananciais da Região Metropolitana de São Paulo e da preocupação dos gestores quanto à inadequação desta água para o abastecimento público, este trabalho apresenta a modelagem matemática como uma ferramenta de auxílio na identificação das causas e minimização de impactos negativos sobre proliferação de algas no reservatório Jundiaí. O modelo CE-QUAL-W2, bidimensional na longitudinal e vertical, é aplicado para a representação da hidrodinâmica e da qualidade da água no reservatório, para posterior avaliação de oxigênio dissolvido e clorofila-a. A calibração e a validação do modelo foram realizadas a partir de dados de monitoramento de perfil e superfície no reservatório, permitindo a caracterização do regime de mistura polimítico e das concentrações de algas e oxigênio dissolvido, entre os anos de 2012 e 2017. Notou-se que as discrepâncias entre as concentrações do epilímnio e do hipolímnio não permanecem por longos períodos, devido à frequência de mistura e estratificação instável no reservatório estudado. Evidenciou-se a necessidade de se caracterizarem as populações de algas e cianobactérias presentes no reservatório, por serem as variáveis de maior influência nos índices de algas e oxigênio. Quanto aos fatores externos que interferem na proliferação de algas, destaca-se o aporte difuso de nutrientes diretamente afluente ao reservatório, sendo também relevantes a radiação solar de onda curta, a elevação de temperatura do ar, e nutrientes provenientes dos tributários e da transferência de água do canal de interligação entre os reservatórios Biritiba e Jundiaí. Alternativas para controle de blooms de algas, no caso em estudo, incluem o controle da utilização de fertilizantes e pesticidas, preservação da mata ciliar e a implantação de bacias de retenção ou de alagados (wetlands). / In the context of water availability compromised by the pollution of water resources in the Metropolitan Region of São Paulo and the concern of managers regarding its inadequacy for water supply, this work presents mathematical modeling as a tool for identifying the causes of and minimizing negative impacts on algal blooms in the Jundiaí Reservoir. CE-QUAL-W2, a two-dimensional longitudinal-vertical model, is applied for hydrodynamics and water quality representation of the reservoir, for further evaluation of dissolved oxygen and chlorophyll-a. Model calibration and validation were performed based on profile and surface monitoring data, allowing the characterization of the polymictic regime and the concentrations of algae and dissolved oxygen, between the years 2012 and 2017. It was noted that the discrepancies between the concentrations of epilimnium and hypolimnium do not remain for long periods, due to the frequency of mixing and unstable stratification in the reservoir. It was evidenced the need to characterize populations of algae and cyanobacteria present in the reservoir, since they are the variables that have the greatest influence on algal and oxygen indices. As for the external factors that interfere in algal proliferation, the diffuse contribution of nutrients directly to the reservoir needs special attention, being also relevant short-wave solar radiation, rise of air temperature, nutrients from the tributaries and transfer from interconnection channel between the Biritiba and Jundiaí reservoirs. Alternatives for control of algae blooms in the present case include control of the use of fertilizers and pesticides, preservation of riparian vegetation, retention basins and wetlands.

No contexto da disponibilidade hídrica comprometida pela poluição de mananciais da Região Metropolitana de São Paulo e da preocupação dos gestores quanto à inadequação desta água para o abastecimento público, este trabalho apresenta a modelagem matemática como uma ferramenta de auxílio na identificação das causas e minimização de impactos negativos sobre proliferação de algas no reservatório Jundiaí. O modelo CE-QUAL-W2, bidimensional na longitudinal e vertical, é aplicado para a representação da hidrodinâmica e da qualidade da água no reservatório, para posterior avaliação de oxigênio dissolvido e clorofila-a. A calibração e a validação do modelo foram realizadas a partir de dados de monitoramento de perfil e superfície no reservatório, permitindo a caracterização do regime de mistura polimítico e das concentrações de algas e oxigênio dissolvido, entre os anos de 2012 e 2017. Notou-se que as discrepâncias entre as concentrações do epilímnio e do hipolímnio não permanecem por longos períodos, devido à frequência de mistura e estratificação instável no reservatório estudado. Evidenciou-se a necessidade de se caracterizarem as populações de algas e cianobactérias presentes no reservatório, por serem as variáveis de maior influência nos índices de algas e oxigênio. Quanto aos fatores externos que interferem na proliferação de algas, destaca-se o aporte difuso de nutrientes diretamente afluente ao reservatório, sendo também relevantes a radiação solar de onda curta, a elevação de temperatura do ar, e nutrientes provenientes dos tributários e da transferência de água do canal de interligação entre os reservatórios Biritiba e Jundiaí. Alternativas para controle de blooms de algas, no caso em estudo, incluem o controle da utilização de fertilizantes e pesticidas, preservação da mata ciliar e a implantação de bacias de retenção ou de alagados (wetlands). / In the context of water availability compromised by the pollution of water resources in the Metropolitan Region of São Paulo and the concern of managers regarding its inadequacy for water supply, this work presents mathematical modeling as a tool for identifying the causes of and minimizing negative impacts on algal blooms in the Jundiaí Reservoir. CE-QUAL-W2, a two-dimensional longitudinal-vertical model, is applied for hydrodynamics and water quality representation of the reservoir, for further evaluation of dissolved oxygen and chlorophyll-a. Model calibration and validation were performed based on profile and surface monitoring data, allowing the characterization of the polymictic regime and the concentrations of algae and dissolved oxygen, between the years 2012 and 2017. It was noted that the discrepancies between the concentrations of epilimnium and hypolimnium do not remain for long periods, due to the frequency of mixing and unstable stratification in the reservoir. It was evidenced the need to characterize populations of algae and cyanobacteria present in the reservoir, since they are the variables that have the greatest influence on algal and oxygen indices. As for the external factors that interfere in algal proliferation, the diffuse contribution of nutrients directly to the reservoir needs special attention, being also relevant short-wave solar radiation, rise of air temperature, nutrients from the tributaries and transfer from interconnection channel between the Biritiba and Jundiaí reservoirs. Alternatives for control of algae blooms in the present case include control of the use of fertilizers and pesticides, preservation of riparian vegetation, retention basins and wetlands.

Bakalauro baigiamajame darbe nagrinėjama paslaugų reikšmė teoriniais aspektais - aptarta jų reikšmė šiuolaikinei ekonomikai ir vartotojams. Išanalizuoti paslaugų apibrėžimai ir savybės. Taip pat teoriškai aptarta paslaugų kokybė, jos samprata ir reikšmė. Išanalizuoti penki iš daugelio siūlomų paslaugų kokybei matuoti ir tirti naudojamų modelių: Ch. Grönroos „Suvoktos paslaugų kokybės modelis“, A. A. Brogowicz, L. M. Delene ir D. M. Lyth sukurtas „Techninės ir funkcinės paslaugų kokybės modelis“, G. Cole ir L. Berry sukurtas „Klaidų analizės modelis“, A. Shahin ir M. Samea modifikuotas ir papildytas „Paslaugų kokybės klaidų modelis“ ir Yu – Hsieh Sung, Su – Houn Liu, Hsiu – Li Liao ir Ching - Min Liu suformuotas „Paslaugų kokybės modelis“. Remiantis teorinėje dalyje išanalizuotu A. A. Brogowicz, L. M. Delene ir D. M. Lyth „Techninės ir funkcinės paslaugų kokybės modeliu“, atliktas UAB „AutoRC“ paslaugų kokybės kiekybinis ir kokybinis tyrimas. Kiekybinio tyrimo duomenys parodė, kad įmonė turi mažai lojalių klientų, kokios įmonės siūlomos paslaugos turi didžiausią paklausą, ir kaip jas vertina klientai. Tyrimo pagalba nustatyta, su kuo klientams asocijuojasi UAB „AutoRC“ įvaizdis, ir kokia jų nuomonė apie serviso reklaminius pranešimus. Atlikta UAB „AutoRC“ funkcinės ir techninės paslaugų kokybės kriterijų analizė. Struktūruotas interviu su įmonės darbuotojais išryškino esmines problemas įmonėje. Kokybinio tyrimo metu nustatytos tobulintinos paslaugų kokybę formuojančios sritys... [toliau žr. visą tekstą] / The Bachelor’s thesis deals with the value of services in theoretical aspects – i.e. their significance to modern economy and customers is described. The definitions and features of the services are analysed. Moreover, theoretical aspects of service quality, its conception and meaning are discussed. The following five models of the many models offered for the measurement and investigation of the service quality are analysed: Ch. Grönroos’ Perceived Service Quality model, Technical and Functional Service Quality Model developed by A.A. Brogowicz, L.M. Delene and D. M. Lyth, Error analysis Model created by G. Coile and L. Berry, the model of Service Quality Gaps modified and supplemented by A. Shahin and M. Samea and Service Quality Model developed by Yu-Hsieh Sung, Su-Houn Liu, Hsiu-Li Liao and Ching-Min Liu. A Quantitative and qualitative research on the service quality of „AutoRC“ UAB has been carried out in accordance with A.A. Brogowicz, L.M. Delene and D. M. Lyth‘s Technical and Functional Service Quality Model, which was analysed in the theoretical part. The data of the quantitative research has revealed that the company has only few loyal customers, it has also conveyed which services offered by the company are in most demand ones ad how they are assessed by the customers. The research helped to identify the associations caused by the image of the company “AutoRC” UAB to the customers as well as customer’s opinion on the advertising. The analysis of functional and... [to full text]

Sensitivity analysis based on a chemical transport model (CTM) serves as an important approach towards better understanding the relationship between trace contaminant levels in the atmosphere and emissions, chemical and physical processes. Previous studies on ozone control identified the high-order Decoupled Direct Method (HDDM) as an efficient tool to conduct sensitivity analysis. Given the growing recognition of the adverse health effects of fine particulate matter (i.e., particles with an aerodynamic diameter less than 2.5 micrometers (PM2.5)), this dissertation presents the development of a HDDM sensitivity technique for particulate matter and its implementation it in a widely used CTM, CMAQ. Compared to previous studies, two new features of the implementation are 1) including sensitivities of aerosol water content and activity coefficients, and 2) tracking the chemical regimes of the embedded thermodynamic model. The new features provide more accurate sensitivities especially for nitrate and ammonium. Results compare well with brute force sensitivities and are shown to be more stable and computationally efficient. Next, this dissertation explores the applications of HDDM. Source apportionment analysis for the Houston region in September 2006 indicates that nonlinear responses accounted for 3.5% to 33.7% of daily average PM2.5, and that PM2.5 formed rapidly during night especially in the presence of abundant ozone and under stagnant conditions. Uncertainty analysis based on the HDDM found that on average, uncertainties in the emissions rates led to 36% uncertainty in simulated daily average PM2.5 and could explain much, but not all, of the difference between simulated and observed PM2.5 concentrations at two observations sites. HDDM is then applied to assess the impact of flare VOC emissions with temporally variable combustion efficiency. Detailed study of flare emissions using the 2006 Texas special inventory indicates that daily maximum 8-hour ozone at a monitoring site can increase by 2.9 ppb when combustion is significantly decreased. The last application in this dissertation integrates the reduced form model into an electricity generation planning model, and enables representation of geospatial dependence of air quality-related health costs in the optimization process to seek the least cost planning for power generation. The integrated model can provide useful advice on selecting fuel types and locations for power plants.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

La qualité des données est une condition commune à tous les projets de technologie de l'information, elle est devenue un domaine de recherche complexe avec la multiplicité et l’expansion des différentes sources de données. Des chercheurs se sont penchés sur l’axe de la modélisation et l’évaluation des données, plusieurs approches ont été proposées mais elles étaient limitées à un domaine d’utilisation bien précis et n’offraient pas un profil de qualité nous permettant d’évaluer un modèle de qualité de données global. L’évaluation basée sur les modèles de qualité ISO a fait son apparition, néanmoins ces modèles ne nous guident pas pour leurs utilisation, le fait de devoir les adapter à chaque cas de figure sans avoir de méthodes précises. Notre travail se focalise sur les problèmes de la qualité des données d'un système ambiant où les contraintes de temps pour la prise de décision sont plus importantes par rapport aux applications traditionnelles. L'objectif principal est de fournir au système décisionnel une vision très spécifique de la qualité des données issues des capteurs. Nous identifions les aspects quantifiables des données capteurs pour les relier aux métriques appropriées de notre modèle de qualité de données spécifique. Notre travail présente les contributions suivantes : (i) création d’un modèle de qualité de données générique basé sur plusieurs standards de qualité existants, (ii) formalisation du modèle de qualité sous forme d’une ontologie qui nous permet l’intégration de ces modèles (de i), en spécifiant les différents liens, appelés relations d'équivalence, qui existent entre les critères composant ces modèles, (iii) proposition d’un algorithme d’instanciation pour extraire le modèle de qualité de données spécifique à partir du modèle de qualité de données générique, (iv) proposition d’une approche d’évaluation globale du modèle de qualité de données spécifique en utilisant deux processus, le premier processus consiste à exécuter les métriques reliées aux données capteurs et le deuxième processus récupère le résultat de cette exécution et utilise le principe de la logique floue pour l’évaluation des facteurs de qualité de notre modèle de qualité de données spécifique. Puis, l'expert établie des valeurs représentant le poids de chaque facteur en se basant sur la table d'interdépendance pour prendre en compte l'interaction entre les différents critères de données et on utilisera la procédure d'agrégation pour obtenir un degré de confiance. En ce basant sur ce résultat final, le composant décisionnel fera une analyse puis prendra une décision. / Data quality is a common condition to all information technology projects; it has become a complex research domain with the multiplicity and expansion of different data sources. Researchers have studied the axis of modeling and evaluating data, several approaches have been proposed but they are limited to a specific use field and did not offer a quality profile enabling us to evaluate a global quality model. The evaluation based on ISO quality models has emerged; however, these models do not guide us for their use, having to adapt them to each scenario without precise methods. Our work focuses on the data quality issues of an ambient system where the time constraints for decision-making is greater compared to traditional applications. The main objective is to provide the decision-making system with a very specific view of the sensors data quality. We identify the quantifiable aspects of sensors data to link them to the appropriate metrics of our specified data quality model. Our work presents the following contributions: (i) creating a generic data quality model based on several existing data quality standards, (ii) formalizing the data quality models under an ontology, which allows integrating them (of i) by specifying various links, named equivalence relations between the criteria composing these models, (iii) proposing an instantiation algorithm to extract the specified data quality model from the generic data quality models, (iv) proposing a global evaluation approach of the specified data quality model using two processes, the first one consists in executing the metrics based on sensors data and the second one recovers the result of the first process and uses the concept of fuzzy logic to evaluate the factors of our specified data quality model. Then, the expert defines weight values based on the interdependence table of the model to take account the interaction between criteria and use the aggregation procedure to get a degree of confidence value. Based on the final result, the decisional component makes an analysis to make a decision.

The Occoquan Watershed is a 1515 square kilometer basin located in northern Virginia and contains two principal waterbodies: the Occoquan Reservoir and Lake Manassas. Both waterbodies are principal drinking water supplies for local residents and experience eutrophication and summer algae growth. They are continuously threatened by new development from the rapid expansion of the greater Washington D.C. region. The Occoquan model, consisting of six HSPF and two CE-QUAL-W2 submodels linked in a complex way, has been developed and applied to simulate hydrology and water quality activities in the two major reservoirs and the associated drainage areas. The studied water quality constituents include temperature, dissolved oxygen, ammonium nitrogen, oxidized nitrogen, orthophosphate phosphorus, and algae. The calibration of the linked model is for the years 1993-95, with a validation period of 1996-97. The results show that a successful calibration can be achieved using the linked approach, with moderate additional effort. The spatial and temporal distribution of hydrology processes, nutrient detachment and transport, stream temperature and dissolved oxygen were well reproduced by HSPF submodels. By using the outputs generated by HSPF submodels, the CE-QUAL-W2 submodels adequately captured the water budgets, hydrodynamics, temperature, temporal and spatial distribution of dissolved oxygen, ammonium nitrogen, oxidized nitrogen, orthophosphate phosphorus, and algae in Lake Manassas and Occoquan Reservoir. This demonstrates the validity of linking two types of state of the art water quality models: the watershed model HSPF and the reservoir model CE-QUAL-W2. One of the advantages of the linked model approach is to develop a direct cause and effect relationship between upstream activities and downstream water quality. Therefore, scenarios of various land use proposals, BMP implementation, and point source management can be incorporated into HSPF applications, so that the CE-QUAL-W2 submodels can use the boundary conditions corresponding with these scenarios to predict the water quality variations in the receiving waterbodies. In this research, two land use scenarios were developed. One represented the background condition assuming all the land covered by forest and the other represented the environmental stress posed by future commercial and residential expansion. The results confirm the increases of external nutrient loads due to urbanization and other human activities, which eventually lead to nutrient enrichment and enhanced algae growth in the receiving waterbodies. The increases of external nutrient loads depend on land use patterns and are not evenly spread across the watershed. The future development in the non urban areas will greatly increase the external nutrient production and BMPs should be implemented to reduce the potential environmental degradation. For the existing urban areas, the model results suggest a potential threshold of nutrient production despite future land development. The model results also demonstrate the catchment function of Lake Manassas in reducing nutrient transport downstream. / Ph. D.

Air Quality Models are defined for prediction and simulation of air pollutant concentrations over a certain period of time. The predictions can be used in setting limits for the emission levels of industrial facilities. The input data for the air quality models are very large and encompass various environmental conditions like wind speed, turbulence, temperature and cloud density. Most air quality models are based on advection-diffusion equations. These differential equations are moderately stiff and require appropriate techniques for fast integration over large intervals of time. Implicit time stepping techniques for solving differential equations being unconditionally stable are considered suitable for the solution. However, implicit time stepping techniques impose certain data dependencies that can cause the parallelization of air quality models to be inefficient. The current approach uses Runge Kutta Chebyshev explicit method for solution of advection diffusion equations. It is found that even if the explicit method used is computationally more expensive in the serial execution, it takes lesser execution time when parallelized because of less complicated data dependencies presented by the explicit time-stepping. The implicit time-stepping on the other hand cannot be parallelized efficiently because of the inherent complicated data dependencies. / Master of Science

In order to meet the US EPA's National Ambient Air Quality Standards as set under the provisions of the Clean Air Act, states and regions throughout the United States are designing cap and trade programs aimed at reducing the emissions of the two dominant precursors for ozone, nitrogen oxides (NOx) and Volatile Organic Compounds (VOCs). While emission cap and trade programs are becoming more common, relatively few analyses have examined the air quality implications of moving emissions from one location to another (due to trading of emissions between facilities), from one sector to another (due to the use of technologies such as Plug-in Electric Hybrid Vehicles - PHEVs), and changing the temporal distribution of emissions (through emissions trading among facilities with different temporal profiles). This thesis will examine, in detail, the air quality implications of two emission cap and trade programs. The first program is a NOx trading program that covers Electricity Generating Units (EGUs) in the Northeastern United States. Results show that refining the temporal limits on this cap and trade program, by charging facilities more to emit NOx on days when ozone is most likely to form, has the potential to significantly reduce NOx emissions and ozone concentrations. Additionally, this research also shows that, for this region, the spatial redistribution of NOx emissions due to trading leads to greater ozone reductions than similar amounts of NOx emission reductions applied evenly across all facilities. Analyses also indicate that displacing emissions from the on-road mobile sector (vehicles) to the EGU sector through the use of PHEVs decreases ozone in most areas, but some highly localized areas show increases in ozone concentration. The second trading program examined in this thesis is limited to Houston, Texas, where a VOC trading program is focused on a sub-set of four Highly Reactive Volatile Organic Compounds (HRVOCs), which have been identified as having substantial ozone formation potential. Work presented in this thesis examined whether this trading program, in its current form or in an expanded form, could lead to air pollution hot spots, due to spatial reallocation of emissions. Results show that the program as currently designed is unlikely to lead to ozone hot spots, so no further spatial limitations are required for this program. Expanding the trading to include Other VOCs, fugitive emissions and chlorine emissions, based on reactivity weighted trading, is also unlikely to lead to the formation of ozone hot spots, and could create more flexibility in a trading market that is currently not very active. Based on these air quality modeling results, policy suggestions are provided that may increase participation in the trading market. These case studies demonstrate that use of detailed air analyses can provide improved designs for increasingly popular emission cap and trade programs, with improved understanding of the impacts of modifying spatial and temporal distributions of emissions. / text