Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Brigham Young University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 7471 - 7500 of 10987

Full-Text Articles in Entire DC Network

Electric Field Gradient Focusing-Uv Detection For Protein Analysis, Shu-Ling Lin Jul 2006

Electric Field Gradient Focusing-Uv Detection For Protein Analysis, Shu-Ling Lin

Theses and Dissertations

Electric field gradient focusing (EFGF) utilizes a hydrodynamic flow and an electric field gradient to focus and concentrate charged analytes and order them in a separation channel according to electrophoretic mobility. Elution can be achieved by decreasing the applied voltage or increasing the hydrodynamic flow. EFGF has the advantages of concentrating a large volume (100 micro-L) of target proteins without significant band broadening and simultaneously removing unwanted components from the sample. Two types of EFGF devices have been investigated to concentrate and separate proteins: a fiber-based EFGF device and a hydrogel-based EFGF device. Using fiber-based EFGF with UV detection, a …

Go to article

Markov Approximations: The Characterization Of Undermodeling Errors, Lei Lei Jul 2006

Markov Approximations: The Characterization Of Undermodeling Errors, Lei Lei

Theses and Dissertations

This thesis is concerned with characterizing the quality of Hidden Markov modeling when learning from limited data. It introduces a new perspective on different sources of errors to describe the impact of undermodeling. Our view is that modeling errors can be decomposed into two primary sources of errors: the approximation error and the estimation error. This thesis takes a first step towards exploring the approximation error of low order HMMs that best approximate the true system of a HMM. We introduce the notion minimality and show that best approximations of the true system with complexity greater or equal to the …

Go to article

The Development Of A Farming Systems Model (Apsim) A Disciplined Approach., Dean Holzworth, Holger Meinke, Peter Devoil, Malcolm Wegener, Neil Huth, Graeme Hammer, Mark Howden, Michael Robertson, Peter Carberry, David Freebairn, Chris Murphy Jul 2006

The Development Of A Farming Systems Model (Apsim) A Disciplined Approach., Dean Holzworth, Holger Meinke, Peter Devoil, Malcolm Wegener, Neil Huth, Graeme Hammer, Mark Howden, Michael Robertson, Peter Carberry, David Freebairn, Chris Murphy

International Congress on Environmental Modelling and Software

The Agricultural Production Systems Simulator (APSIM) is a mature and stable modelling framework used widely in Australia in the domain of farming systems research and extension. It is capable of simulating a diverse range of farming systems including broad acre dryland and irrigated cropping, small holder farming, on-farm agroforestry systems including the interaction of trees and crops, and through collaboration with other groups, integrated stock and cropping enterprises. APSIM was developed primarily as a research tool to investigate on-farm management practices, natural resource issues including salinity and solute movement, climate risk studies looking at modifying farm practices and climate change …

Go to article

Model-Data Fusion In The Studies Of Terrestrial Carbon Sink, G. A. Alexandrov, D. Chan, M. Chen, K. Gurney, K. Higuchi, A. Ito, C. D. Jones, Alexander Komarov, K. Mabuchi, D. M. Matross, F. Veroustraete, W. W. Verstraeten Jul 2006

Model-Data Fusion In The Studies Of Terrestrial Carbon Sink, G. A. Alexandrov, D. Chan, M. Chen, K. Gurney, K. Higuchi, A. Ito, C. D. Jones, Alexander Komarov, K. Mabuchi, D. M. Matross, F. Veroustraete, W. W. Verstraeten

International Congress on Environmental Modelling and Software

Current uncertainty in quantifying the global carbon budget remains a major contributing source of uncertainty in reliably projecting future climate change. Furthermore, quantifying the global carbon budget and characterizing uncertainties have emerged as critical to a successful implementation of United National Framework Convention on Climate Change and its Kyoto Protocol. Beyond fundamental quantification, attribution of the processes responsible for the so-called ‘residual terrestrial uptake’ is important to the carbon cycle communities’ ability to simulated the future response of the terrestrial biosphere to climate change and intentional sequestration activities. This paper’s objective is to describe the efforts of the workshop participants …

Go to article

Ten Steps Applied To Development And Evaluation Of Process-Based Biogeochemical Models Of Estuaries, Barbara J. Robson, Ian T. Webster, David P. Hamilton, Terence Chan, Teemu Kokkonen Jul 2006

Ten Steps Applied To Development And Evaluation Of Process-Based Biogeochemical Models Of Estuaries, Barbara J. Robson, Ian T. Webster, David P. Hamilton, Terence Chan, Teemu Kokkonen

International Congress on Environmental Modelling and Software

The procedures involved in model development may be set out ten-step process, beginning with defining the purpose of the model and ending with evaluation of the appropriateness and utility of the completed model. This process, recently outlined by Jakerman et al. [2006], is often iterative as model development is a continuous process that refines and improves the indented capacity of the model. Here, we show how the ten steps of model development are relevant to process-based biogeochemical modeling of aquatic systems, using examples from two case studies: a model of phytoplankton succession and nutrient concentrations in the Swan-Canning Estuary (Western …

Go to article

Systematic Simplification Of Mechanistic Models, Neil Crout, Glen Cox, James Gibbons Jul 2006

Systematic Simplification Of Mechanistic Models, Neil Crout, Glen Cox, James Gibbons

International Congress on Environmental Modelling and Software

Models of environmental systems are often complex, reflecting the complexity of the systems they try and describe. This complexity is difficult to manage and, especially in the face of limited observed data, there is a risk that models become over-parameterised with the result that predictions are less reliable than they need be. An approach to investigating the influence of model complexity on prediction accuracy is to compare the performance of alternative (simpler) model formulations. However this is difficult to achieve in practice as the process of simplification can be time-consuming with the consequence that only a few alternative formulations can …

Go to article

Bayesian Decision Networks - Going Beyond Expert Elicitation For Parameterisation And Evaluation Of Ecological Endpoints., C. A. Pollino, Barry T. Hart Jul 2006

Bayesian Decision Networks - Going Beyond Expert Elicitation For Parameterisation And Evaluation Of Ecological Endpoints., C. A. Pollino, Barry T. Hart

International Congress on Environmental Modelling and Software

Ecological and integrative analyses routinely involve the synthesis of a range of information sources into a single model. Bayesian decision networks (BDN) are increasingly being used for this purpose because they are flexible, transparent and relatively easy to use. Indeed, BDNs offer a scientific and pragmatic approach to improve decision-making in environmental management, directly addressing management needs, while promoting stakeholder participatory processes. However, despite their advantages, many BDNs developed to meet such needs are not being developed or applied to their full potential. The majority of BDNs published to date rely only on expert opinion to parameterise and evaluate ecologically …

Go to article

Mike Basin, David Wood Jul 2006

Mike Basin, David Wood

International Congress on Environmental Modelling and Software

MIKE BASIN addresses water allocation, conjunctive use, reservoir operation, or water quality issues. It couples ArcGIS with hydrologic modeling to provide basin-scale solutions. The MIKE BASIN philosophy is to keep modeling simple and intuitive, yet provide in-depth insight for planning and management. In MIKE BASIN, the emphasis is on both simulation and visualization in both space and time, making it appropriate for building understanding and consensus. MIKE BASIN is a quasi-steady-state mass balance model, allowing for routed river flows. The water quality solution assumes purely advective transport. Decay during transport can be modeled. The groundwater description uses the linear reservoir …

Go to article

Model-Data Fusion In The Studies Of Terrestrial Carbon Sink, G. A. Alexandrov, D. Chan, M. Chen, K. Gurney, K. Higuchi, A. Ito, C. D. Jones, Alexander Komarov, K. Mabuchi, D. M. Matross, F. Veroustraete, W. W. Verstraeten Jul 2006

Model-Data Fusion In The Studies Of Terrestrial Carbon Sink, G. A. Alexandrov, D. Chan, M. Chen, K. Gurney, K. Higuchi, A. Ito, C. D. Jones, Alexander Komarov, K. Mabuchi, D. M. Matross, F. Veroustraete, W. W. Verstraeten

International Congress on Environmental Modelling and Software

Current uncertainty in quantifying the global carbon budget remains a major contributing source of uncertainty in reliably projecting future climate change. Furthermore, quantifying the global carbon budget and characterizing uncertainties have emerged as critical to a successful implementation of United National Framework Convention on Climate Change and its Kyoto Protocol. Beyond fundamental quantification, attribution of the processes responsible for the so-called ‘residual terrestrial uptake’ is important to the carbon cycle communities’ ability to simulated the future response of the terrestrial biosphere to climate change and intentional sequestration activities. This paper’s objective is to describe the efforts of the workshop participants …

Go to article

Prescriptive Treatment Optimization Using A Genetic Algorithm: A Tool For Forest Management, John Dewey, Frederick Maier, Walter D. Potter, Donald Nute, H. M. Rauscher, Mark Twery, Peter Knopp, Scott Thomasma Jul 2006

Prescriptive Treatment Optimization Using A Genetic Algorithm: A Tool For Forest Management, John Dewey, Frederick Maier, Walter D. Potter, Donald Nute, H. M. Rauscher, Mark Twery, Peter Knopp, Scott Thomasma

International Congress on Environmental Modelling and Software

This paper describes research on the use of a multiobjective genetic algorithm (GA) to optimize prescriptive treatment plans for forest management. The algorithm is novel, in that (1) the plans generated by the algorithm are highly specific, stating precisely when and where treatments are to be applied; and (2) logical rules and inference engines developed for a decision support system are used to evaluate the fitness of each plan. Fitness is based upon satisfaction of varied and often incompatible goals. The current (generational) GA has been compared in experiments to hill-climbing and simulated annealing algorithms, as well as to a …

Go to article

Imagine – Scenario Development For Environmental Impact Assessment Studies, T. Wagener, Y. Liu, S. Stewart, H. Hartman, M. Mahmoud Jul 2006

Imagine – Scenario Development For Environmental Impact Assessment Studies, T. Wagener, Y. Liu, S. Stewart, H. Hartman, M. Mahmoud

International Congress on Environmental Modelling and Software

Scenario analysis is a process of evaluating possible future events through the consideration of alternative possible (though not equally likely) outcomes (scenarios). The analysis is designed to enable improved decision-making and assessment through a more complete consideration of possible outcomes and their implications. The development of strategies for water resources planning and management and the assessment of impacts of potential environmental change are often guided by analyzing multiple future scenarios within an Integrated Modeling (IM) framework, usually driven by forcing derived from global climate models and/or possible future socio-economic changes. The process of scenario development involves making explicit and/or implicit …

Go to article

Prescriptive Treatment Optimization Using A Genetic Algorithm: A Tool For Forest Management, John Dewey, Frederick Maier, Walter D. Potter, Donald Nute, H. M. Rauscher, Mark Twery, Peter Knopp, Scott Thomasma Jul 2006

Prescriptive Treatment Optimization Using A Genetic Algorithm: A Tool For Forest Management, John Dewey, Frederick Maier, Walter D. Potter, Donald Nute, H. M. Rauscher, Mark Twery, Peter Knopp, Scott Thomasma

International Congress on Environmental Modelling and Software

This paper describes research on the use of a multiobjective genetic algorithm (GA) to optimize prescriptive treatment plans for forest management. The algorithm is novel, in that (1) the plans generated by the algorithm are highly specific, stating precisely when and where treatments are to be applied; and (2) logical rules and inference engines developed for a decision support system are used to evaluate the fitness of each plan. Fitness is based upon satisfaction of varied and often incompatible goals. The current (generational) GA has been compared in experiments to hill-climbing and simulated annealing algorithms, as well as to a …

Go to article

Data Mining As A Tool For Environmental Scientists, J. M. Spate, Karina Gibert, Miquel Sànchez-Marrè, E. Frank, Joaquim Comas, Ioannis N. Athanasiadis Jul 2006

Data Mining As A Tool For Environmental Scientists, J. M. Spate, Karina Gibert, Miquel Sànchez-Marrè, E. Frank, Joaquim Comas, Ioannis N. Athanasiadis

International Congress on Environmental Modelling and Software

Over recent years a huge library of data mining algorithms has been developed to tackle a variety of problems in fields such as medical imaging and network traffic analysis. Many of these techniques are far more flexible than more classical modelling approaches and could be usefully applied to data-rich environmental problems. Certain techniques such as Artificial Neural Networks, Clustering, Case-Based Reasoning and more recently Bayesian Decision Networks have found application in environmental modelling while other methods, for example classification and association rule extraction, have not yet been taken up on any wide scale. We propose that these and other data …

Go to article

Integrated Modeling: Examining The Fate And Transport Of Contaminants In Canadian Lakes And Rivers., William Booty, David Lam, Craig Mccrimmon Jul 2006

Integrated Modeling: Examining The Fate And Transport Of Contaminants In Canadian Lakes And Rivers., William Booty, David Lam, Craig Mccrimmon

International Congress on Environmental Modelling and Software

With the ever increasing introduction of chemicals to the environment (approx. 4000 new chemicals are registered each day), scientists and program managers are faced with an apparently endless and overwhelming task of examining the possible ecological risks of these new chemicals as well as the existing chemicals in aquatic ecosystems. It is also well recognized that no single model will be capable of dealing with all of the different types of chemicals and the environments that these chemicals are released into. It is therefore necessary to be able to integrate a spectrum of best practice models into a system that …

Go to article

Dealing With Uncertainty And Sensitivity Issues In Process-Based Models Of Carbon And Nitrogen Cycles In Northern Forest Ecosystems, G. R. Larocque, J. S. Bhatti, A. M. Gordon, N. Luckai, Jinxun Liu, Shuguang Liu, P. A. Arp, C. -F Zhang, Alexander Komarov, Pavel Grabarnik, M. Wattenbach, C. Peng, Jianfeng Sun, Thomas White Jul 2006

Dealing With Uncertainty And Sensitivity Issues In Process-Based Models Of Carbon And Nitrogen Cycles In Northern Forest Ecosystems, G. R. Larocque, J. S. Bhatti, A. M. Gordon, N. Luckai, Jinxun Liu, Shuguang Liu, P. A. Arp, C. -F Zhang, Alexander Komarov, Pavel Grabarnik, M. Wattenbach, C. Peng, Jianfeng Sun, Thomas White

International Congress on Environmental Modelling and Software

Many process-based models on carbon (C) and nitrogen (N) cycles have been developed for northern forest ecosystems. These models are widely used to evaluate the long-term decisions in forest management dealing with effects like particulate pollution, productivity and climate change. Regarding climate change, one of the key questions that have sensitive political implications is whether northern forests will sequester atmospheric C or not. Whilst many process-based models have been tested for accuracy by evaluating or validating against observed data, few have dealt with the complexity of the incorporated procedures to estimate uncertainties associated with model predictions or the sensitivity of …

Go to article

On The Prediction Of The Ecological Status Of Human-Altered Streams And Its Rule-Based Interpretation, Terence A. Etchells, Alfredo Vellido, E. Martí, Paulo J. G. Lisboa, Joaquim Comas Jul 2006

On The Prediction Of The Ecological Status Of Human-Altered Streams And Its Rule-Based Interpretation, Terence A. Etchells, Alfredo Vellido, E. Martí, Paulo J. G. Lisboa, Joaquim Comas

International Congress on Environmental Modelling and Software

The recent Water Framework Directive of the European Union set year 2015 as their target for freshwater and coastal ecosystems all across Europe to achieve good ecological status. This study concerns the analysis of the empirical data from the knowledge base of an environmental decision support system developed within the European project STREAMES. These data, which come from several low-order streams located mostly on the Mediterranean region, consist of measurements of several physical, chemical and biological variables. We aim to classify these data according to the ecological status of the streams they correspond to, where stream nutrient retention efficiency (a …

Go to article

Upscaling Terrestrial Carbon Dynamics From Sites To Regions With Uncertainty Measures: The Gems Experience, Shuguang Liu, Z. Li, Jinxun Liu, Thomas R. Loveland, M. Chen, Larry L. Tieszen Jul 2006

Upscaling Terrestrial Carbon Dynamics From Sites To Regions With Uncertainty Measures: The Gems Experience, Shuguang Liu, Z. Li, Jinxun Liu, Thomas R. Loveland, M. Chen, Larry L. Tieszen

International Congress on Environmental Modelling and Software

Upscaling the spatial and temporal changes of carbon stocks and fluxes from sites to regions is challenging owing to the spatial and temporal variances and covariance of driving variables and the uncertainties in both the model and the input data. Although various modeling approaches have been developed to facilitate the upscaling process, few deal with error transfer from model input to output, and error propagation in time and space. We develop the General Ensemble Biogeochemical Modeling System (GEMS) for upscaling carbon stocks and fluxes from sites to regions with measures of uncertainty. GEMS relies on site-scale biogeochemical models (e.g., the …

Go to article

Numerical Simulation Of Flow And Tracer Transport In A Disinfection Contact Tank, C. Gualtieri Jul 2006

Numerical Simulation Of Flow And Tracer Transport In A Disinfection Contact Tank, C. Gualtieri

International Congress on Environmental Modelling and Software

Chlorine is extensively used to disinfect drinking water supply. However, the design of chlorine contact tank is usually based on the volume displacement criterion, paying attention that detention time would be at least of half an hour. This criterion relies upon the assumption that plug-flow conditions hold along the tank. However, the existence and arrangement of baffles in the tank, and the tank inlet and outlet configurations can result in a much more complex flow pattern, where turbulent mixing, dead-zones and short-circuiting exist. This situation could result in an inefficient use of chlorine due to the formation of potentially carcinogenic …

Go to article

Tornado: A Versatile And Efficient Modelling And Virtual Experimentation Kernel For Water Quality Systems, Filip Claeys, Dirk J. W. De Pauw, Lorenzo Benedetti, Ingmar Nopens, Peter A. Vanrolleghem Jul 2006

Tornado: A Versatile And Efficient Modelling And Virtual Experimentation Kernel For Water Quality Systems, Filip Claeys, Dirk J. W. De Pauw, Lorenzo Benedetti, Ingmar Nopens, Peter A. Vanrolleghem

International Congress on Environmental Modelling and Software

Recently, a new kernel for modelling and virtual experimentation (i.e. any evaluation of a model) in the domain of water quality management was developed. This kernel was named “Tornado” and will be included in the new generation of the WEST product family, as well as in several other products (e.g. DHI’s MOUSE-TRAP) and projects. Most important issues during development were versatility and efficiency. This paper focuses mainly on the rationale for the new development, and the major features of the resulting kernel. It is argued that classical approaches (such as the adoption of MATLAB/SIMULINK, custom FORTRAN codes and/or domain-specific simulators) …

Go to article

An Optimal Control And Options Theory Approach To Forecasting And Managing Sustainable Systems, Y. Shastri, U. Diwekar Jul 2006

An Optimal Control And Options Theory Approach To Forecasting And Managing Sustainable Systems, Y. Shastri, U. Diwekar

International Congress on Environmental Modelling and Software

Sustainable management of the natural systems is essential in the presence of anthropogenic andnatural disasters. Fisher information based measure and hypothesis have been proposed to quantify the sustainabilityof natural systems, which are used in this work to formulate management objectives. Since uncertaintyis omnipresent in natural systems, its consideration is important. Real options theory deals extensively with therepresentation and forecasting of uncertainty. The options theory, with the Ito mean reverting process, is usedto represent uncertainty, and optimal control theory is used to derive time dependent decisions. The idea isimplemented on a three species predator-prey model. The results highlight the effect of …

Go to article

Ten Steps Applied To Development And Evaluation Of Process-Based Biogeochemical Models Of Estuaries, Barbara J. Robson, Ian T. Webster, David P. Hamilton, Terence Chan, Teemu Kokkonen Jul 2006

Ten Steps Applied To Development And Evaluation Of Process-Based Biogeochemical Models Of Estuaries, Barbara J. Robson, Ian T. Webster, David P. Hamilton, Terence Chan, Teemu Kokkonen

International Congress on Environmental Modelling and Software

The procedures involved in model development may be set out ten-step process, beginning with defining the purpose of the model and ending with evaluation of the appropriateness and utility of the completed model. This process, recently outlined by Jakerman et al. [2006], is often iterative as model development is a continuous process that refines and improves the indented capacity of the model. Here, we show how the ten steps of model development are relevant to process-based biogeochemical modeling of aquatic systems, using examples from two case studies: a model of phytoplankton succession and nutrient concentrations in the Swan-Canning Estuary (Western …

Go to article

Risk Assessment Module Of The Iwa/Cost Simulation Benchmark: Validation And Extension Proposal., Jordi Dalmau, Ignasi Rodríguez-Roda, Jean-Philippe Steyer, Joaquim Comas Jul 2006

Risk Assessment Module Of The Iwa/Cost Simulation Benchmark: Validation And Extension Proposal., Jordi Dalmau, Ignasi Rodríguez-Roda, Jean-Philippe Steyer, Joaquim Comas

International Congress on Environmental Modelling and Software

The IWA/COST simulation benchmark platform has been widely used to evaluate and compare different activated sludge control strategies. The IWA/COST simulation benchmark provides performance indices like the effluent water quality, operating costs and controller performance (Copp, 2002), all of them quantitative. However, these indices do not take into account the biomass separation related problems which at present cannot be quantitatively modelled. A qualitative Risk Assessment Module adaptable to any simulation benchmark platform has been developed for the activated sludge systems. As a consequence, and in order to improve the quantitative performance indices, lately the anaerobic digestion model number 1 (ADM1) …

Go to article

Uncertainty Analysis Associated With Rainfall Spatial Distribution In An Experimental Semiarid Watershed, Northeastern Brazil, Lúcio Flávio Ferreira Moreira, A. M. Righetto, V. M. De A. Medeiros Jul 2006

Uncertainty Analysis Associated With Rainfall Spatial Distribution In An Experimental Semiarid Watershed, Northeastern Brazil, Lúcio Flávio Ferreira Moreira, A. M. Righetto, V. M. De A. Medeiros

International Congress on Environmental Modelling and Software

In this paper the main goal was to analyze the effect of spatial variability of rainfall on runoff in an experimental monitored watershed (2.108 km2) located on a semiarid region (Seridó Potiguar), Rio Grande do Norte-Brazil. To accomplish this, a rainfall-runoff-sediment hydrologic model was used. The study area was divided into 143 elements (planes and channels). Rainfall spatial distribution, estimated using the inverse of distance method, was used as input to calculate rainfall spatial variability index for three observed storm events and different combinations of recording gauge arrangements. This index was considered in this study as an indicator used to …

Go to article

Moira-Plus: A Decision Support System For The Management Of Complex Fresh Water Ecosystems Contaminated By Radionuclides And Heavy Metals, Luigi Monte, Lars Håkanson, D. Hofman, John Brittain, Eduardo Gallego, Antonio Jimenez, Giacomo Angeli Jul 2006

Moira-Plus: A Decision Support System For The Management Of Complex Fresh Water Ecosystems Contaminated By Radionuclides And Heavy Metals, Luigi Monte, Lars Håkanson, D. Hofman, John Brittain, Eduardo Gallego, Antonio Jimenez, Giacomo Angeli

International Congress on Environmental Modelling and Software

The accidental release of radioactive substances into the environment leads to the necessity of applying suitable countermeasures for the restoration of the polluted environment. However, despite their obvious benefits, such interventions may result in detrimental effects of economic, ecological and social nature that must be carefully evaluated. MOIRA–PLUS is a PC-based user-friendly, Computerised Decision Support System (CDSS) that helps decision makers to choose optimal countermeasure strategies for different kinds of aquatic ecosystems and contamination scenarios. CDSS MOIRA-PLUS is based on: a) Validated models to evaluate the behaviour of radionuclides in contaminated water bodies and biota and to assess the effect …

Go to article

Modeling Soil-Water Dynamics For Diverse Environmental Needs, Pierre Martin, Rabi H. Mohtar, Pascal Clouvel, Erik Braudeau Jul 2006

Modeling Soil-Water Dynamics For Diverse Environmental Needs, Pierre Martin, Rabi H. Mohtar, Pascal Clouvel, Erik Braudeau

International Congress on Environmental Modelling and Software

Accurate representation of the top soil matrix with special attention to the scales present is important to the dynamics of water flow and fate of pollution at field, farm and watershed scales. It is also important from an agronomic stand point since agriculture still constitutes the main source of pollution at a time when many agronomic models still use empirical notions of soil hydraulic properties. The soil dynamics literature describes soil hydraulic properties independently from the soil-water medium hydro-structural dynamics. This leads to an empirical approach to represent and estimate soil hydro-structural properties such as shrinkage, water potential, field capacity, …

Go to article

Data Mining Approaches To Explaining Aerosol Formation, Saara Hyvonen, Heikki Junninen, Lauri Laakso, Miikka Dal Maso, Tiia Gronholm, Boris Bonn, Petri Keronen, Pasi Aalto, Veijo Hiltunen, Toivo Pohja, Samuli Launiainen, Pertti Hari, Heikki Mannila, H.C. Hansoon, M. Kulmala Jul 2006

Data Mining Approaches To Explaining Aerosol Formation, Saara Hyvonen, Heikki Junninen, Lauri Laakso, Miikka Dal Maso, Tiia Gronholm, Boris Bonn, Petri Keronen, Pasi Aalto, Veijo Hiltunen, Toivo Pohja, Samuli Launiainen, Pertti Hari, Heikki Mannila, H.C. Hansoon, M. Kulmala

International Congress on Environmental Modelling and Software

Atmospheric aerosol particle formation is frequently observed in various environments. Yet, despite numerous studies, processes behind these so called nucleation events remain unclear. In this work we describe the use of data mining techniques to detect factors influencing particle formation. These techniques are applied to a dataset of eight years of 80 variables collected at the boreal forest station (SMEAR II) in Southern Finland, including air pollutant, weather, gas and particle measurements. In a previous study classification methods have been used together with feature selection in order to understand what causes nucleation. Each day was classified as an event day, …

Go to article

Risk Assessment Module Of The Iwa/Cost Simulation Benchmark: Validation And Extension Proposal., Jordi Dalmau, Ignasi Rodríguez-Roda, Jean-Philippe Steyer, Joaquim Comas Jul 2006

Risk Assessment Module Of The Iwa/Cost Simulation Benchmark: Validation And Extension Proposal., Jordi Dalmau, Ignasi Rodríguez-Roda, Jean-Philippe Steyer, Joaquim Comas

International Congress on Environmental Modelling and Software

The IWA/COST simulation benchmark platform has been widely used to evaluate and compare different activated sludge control strategies. The IWA/COST simulation benchmark provides performance indices like the effluent water quality, operating costs and controller performance (Copp, 2002), all of them quantitative. However, these indices do not take into account the biomass separation related problems which at present cannot be quantitatively modelled. A qualitative Risk Assessment Module adaptable to any simulation benchmark platform has been developed for the activated sludge systems. As a consequence, and in order to improve the quantitative performance indices, lately the anaerobic digestion model number 1 (ADM1) …

Go to article

Decision Support System For The Assessment And Evaluation Of Ecological Impacts On Aquatic Ecosystems: Objectives And Framework, Paola Agostini, Elena Semenzin, A. Critto, Christian Micheletti, Paulo Nunes, Andrea Ghermandi, Stefania Gottardo, S. Giove, Dick De Zwart, Werner Brack, Antonio Marcomini Jul 2006

Decision Support System For The Assessment And Evaluation Of Ecological Impacts On Aquatic Ecosystems: Objectives And Framework, Paola Agostini, Elena Semenzin, A. Critto, Christian Micheletti, Paulo Nunes, Andrea Ghermandi, Stefania Gottardo, S. Giove, Dick De Zwart, Werner Brack, Antonio Marcomini

International Congress on Environmental Modelling and Software

The EU Water Framework Directive (WFD), establishing stringent quality objectives for European basins in the next years, prompts for the development of new tools to evaluate and improve the ecological status over European rivers. The present paper will provide an overview of the main activities carried out in the DECIS subproject within MODELKEY, an European research project, funded by the European Commission, aimed to contribute to the assessment, understanding and prediction of the impacts of environmental toxicants on biodiversity in aquatic ecosystems. The main aim of DECIS is to develop a Decision Support System (DSS) that includes all project deliverables …

Go to article

Integrated Modeling: Examining The Fate And Transport Of Contaminants In Canadian Lakes And Rivers., William Booty, David Lam, Craig Mccrimmon Jul 2006

Integrated Modeling: Examining The Fate And Transport Of Contaminants In Canadian Lakes And Rivers., William Booty, David Lam, Craig Mccrimmon

International Congress on Environmental Modelling and Software

With the ever increasing introduction of chemicals to the environment (approx. 4000 new chemicals are registered each day), scientists and program managers are faced with an apparently endless and overwhelming task of examining the possible ecological risks of these new chemicals as well as the existing chemicals in aquatic ecosystems. It is also well recognized that no single model will be capable of dealing with all of the different types of chemicals and the environments that these chemicals are released into. It is therefore necessary to be able to integrate a spectrum of best practice models into a system that …

Go to article

Lake Erie Hypoxia Simulations With Elcom-Caedym, Luis F. León, Ralph E. H. Smith, Jose R. Romero, Robert E. Hecky Jul 2006

Lake Erie Hypoxia Simulations With Elcom-Caedym, Luis F. León, Ralph E. H. Smith, Jose R. Romero, Robert E. Hecky

International Congress on Environmental Modelling and Software

This paper presents the simulation of the dissolved oxygen (DO) dynamics in the central basin of Lake Erie using a three-dimensional hydrodynamic model (ELCOM) coupled with an aquatic ecological model (CAEDYM). The objective was to simulate the recurrent hypoxic conditions that occur in the shallow hypolimnion of the central basin of the lake after the onset of stratification. In early spring, oxygen concentrations are relatively high, but by late summer, large areas in the central basin of Lake Erie are effectively hypoxic (andlt;2 mg l-1). This numerical modeling study successfully reproduced horizontal variability and vertical decay of dissolved oxygen during …

Go to article

First Prev Next Last