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 6181 - 6210 of 8049

Full-Text Articles in Entire DC Network

A Framework For Spatio-Temporal Data Analysis And Hypothesis Exploration, Alexander Campbell, Binh Pham, Yu-Chu Tian Jul 2006

A Framework For Spatio-Temporal Data Analysis And Hypothesis Exploration, Alexander Campbell, Binh Pham, Yu-Chu Tian

International Congress on Environmental Modelling and Software

We present a general framework for pattern discovery and hypothesis exploration in spatio-temporaldata sets that is based on delay-embedding. This is a remarkable method of nonlinear time-series analysis thatallows the full phase-space behaviour of a system to be reconstructed from only a single observable (accessiblevariable). Recent extensions to the theory that focus on a probabilistic interpretation extend its scope and allowpractical application to noisy, uncertain and high-dimensional systems. Our framework uses these extensions toaid alignment of spatio-temporal sub-models (hypotheses) to empirical data - for example, satellite images plusremote-sensing - and to explore behaviours consistent with this alignment. The novel aspect …

Go to article

Non-Linear, Multivariate Forecasting Of Hydrologic And Anthropogenic Responses To Meteorological Forcing, Edwin Roehl, Terry Murray Jul 2006

Non-Linear, Multivariate Forecasting Of Hydrologic And Anthropogenic Responses To Meteorological Forcing, Edwin Roehl, Terry Murray

International Congress on Environmental Modelling and Software

Managers and users of natural resources often face two challenging problems. One is forecasting future natural system conditions for optimal resource allocation. Here, the natural system is comprised of the weather and a dependant hydrologic system that contains a water resource. The second problem is forecasting the behavior of a combined natural and man-made system, which also includes anthropogenic resource consumers. Even though detailed meteorological forecasting over weeks and months is impractical, hydrologic behaviors such as groundwater cycling can transpire over months and years. Alternatively, man-made systems exhibit behaviors that both lag and lead causal forcing, e.g., seasonal weather changes. …

Go to article

Structure - Fate - Relationships Of Organic Chemicals, Rainer Brüggemann, Guillermo Restrepo, Kristina Voigt Jul 2006

Structure - Fate - Relationships Of Organic Chemicals, Rainer Brüggemann, Guillermo Restrepo, Kristina Voigt

International Congress on Environmental Modelling and Software

The evaluation of the potential risk of chemicals receives again a lot of interest due to the renewed chemicals’ policy in the EU. The model package E4CHEM (Exposure Estimation for Potentially Ecotoxic Environmental Chemicals), already developed 1984-1992, is presented in this paper. This is a model which on the one side needs less information or input parameters as the often applied EUSES (European Union System for the Evaluation of Substances) and on the other side provides modules, like EXWAT (Model for the behaviour of the chemical in rivers)) and DTEST (Automatic Data Estimation), which as such are not contained in …

Go to article

Current Trends In Environmental Modelling With Uncertainty., Jiří Hřebíček, Jan Pesl Jul 2006

Current Trends In Environmental Modelling With Uncertainty., Jiří Hřebíček, Jan Pesl

International Congress on Environmental Modelling and Software

The important characteristic feature of environmental modelling is the complexity and uncertainty of its mathematical representation (uncertainty of formula). Imprecision of its input data is another characteristic feature, where it is not possible to omit influences of primary monitoring (e.g. gaps of data, errors of measuring facilities, human factor, etc). Many parameters in algorithms and their mathematical formulations are substituted by empirical constants in praxis, although it is well known that their values are very volatile and input data are not validated. Nowadays, information and communication technology (ICT) capabilities are growing rapidly and applied mathematical software (e.g. computer algebra systems, …

Go to article

Ten Iterative Steps In Development And Evaluation Of Environmental Models, A. J. Jakeman, R. A. Letcher, J. P. Norton Jul 2006

Ten Iterative Steps In Development And Evaluation Of Environmental Models, A. J. Jakeman, R. A. Letcher, J. P. Norton

International Congress on Environmental Modelling and Software

Models are increasingly being relied upon to inform and support natural resource management. They are incorporating an ever broader range of disciplines and now often confront people without strong quantitative or model-building backgrounds. These trends imply a need for wider awareness of what constitutes good model-development practice, including reporting of models to users and sceptical review of models by users. To this end the paper outlines ten basic steps of good, disciplined model practice. The aim is to develop purposeful, credible models from data and prior knowledge, in consort with end-users, with every stage open to critical review and revision. …

Go to article

A Simulation Model Of Land-Use Change In The Lake Tahoe Basin Of California And Nevada, As Used In A Decision-Support System, Mark L. Hessenflow, David L. Halsing Jul 2006

A Simulation Model Of Land-Use Change In The Lake Tahoe Basin Of California And Nevada, As Used In A Decision-Support System, Mark L. Hessenflow, David L. Halsing

International Congress on Environmental Modelling and Software

The Tahoe Land-Use Change model is a stochastic, spatially explicit simulation of future land-use change—in particular, development and retirement of individual parcels—in the Lake Tahoe Basin of California and Nevada. The Federal, State, and regional management agencies responsible for the basin are revising and integrating their 20-year plans to meet various goals, including maintaining or improving several environmental (e.g., lake clarity, forest health) and socioeconomic (e.g., affordable housing) characteristics. To assist this effort, the model projects the long-term outcomes of land-use-management decisions, including those relating to existing and potential government regulations, development activities, and conservation practices. The model results are …

Go to article

A Decision Support System For Energy Production From Renewable Resources: Logistics Aspects Of Sustainable Forest Biomass Collection, R. Minciardi, M. Robba, Roberto Sacile, F. Frombo, Fulvia Rosso Jul 2006

A Decision Support System For Energy Production From Renewable Resources: Logistics Aspects Of Sustainable Forest Biomass Collection, R. Minciardi, M. Robba, Roberto Sacile, F. Frombo, Fulvia Rosso

International Congress on Environmental Modelling and Software

The consequences of the use of traditional fossil fuels has led, in the last years, the European Union to promote and encourage the development and the use of renewable energies rather than the traditional ones. Energy production from forest biomass does not involve the CO2 increase in the atmosphere, contributing in this way to the duties assumed by the European Community during the International Conference of Kyoto (1997). The developed DSS, that is a generalization and the further research activity presented in a previous work by the same authors (Freppaz et al. [2004]), is based on the integration of Geographic …

Go to article

Features Of Advanced Decision Support Systems For Environmental Studies, Management, And Regulation, Edwin Roehl, Ruby Daamen, Paul A. Conrads Jul 2006

Features Of Advanced Decision Support Systems For Environmental Studies, Management, And Regulation, Edwin Roehl, Ruby Daamen, Paul A. Conrads

International Congress on Environmental Modelling and Software

Natural resource managers and users face difficult challenges when managing the interactions between natural and man-made systems. Even though the collective interests and computer skills of the community of managers, scientists, and other stakeholders are quite varied, there is an overarching need for equal access by all to the scientific knowledge needed to make the best possible decisions. A decision support system (DSS) can meet this need. DSS have been described as, “computer-based systems (for) helping decision-makers to solve various semi structured and unstructured problems involving multiple attributes, objectives, and goals… Historically, the majority of DSSs have been either computer …

Go to article

Scenario Analysis In Water Resources Management Under Data Uncertainty, Antonio Manca, Giovanni M. Sechi, Andrea Sulis, Paola Zuddas Jul 2006

Scenario Analysis In Water Resources Management Under Data Uncertainty, Antonio Manca, Giovanni M. Sechi, Andrea Sulis, Paola Zuddas

International Congress on Environmental Modelling and Software

In water resources management problems, uncertainty is mainly associated with the value of hydrological exogenous inflows and demand patterns. Deterministic models are inadequate to represent these problems and traditional stochastic optimization models cannot be used if there is insufficient statistical information to support the model. In this paper the uncertainty is modelled by a scenario approach in a multistage environment which includes different possible system configurations in a wide time horizon. A robust chance optimization model is used in order to obtain a so-called barycentric value with respect to decision variables. The successive reoptimization step, based on this barycentric solution, …

Go to article

Identification Of Alternatives Strengths And Weaknesses During The Conceptual Design Of Environmental Systems, Xavier Flores Alsina, Manel Poch, Laureano Jiménez, Rene Bañares-Alcántara, Ignasi Rodríguez Roda Jul 2006

Identification Of Alternatives Strengths And Weaknesses During The Conceptual Design Of Environmental Systems, Xavier Flores Alsina, Manel Poch, Laureano Jiménez, Rene Bañares-Alcántara, Ignasi Rodríguez Roda

International Congress on Environmental Modelling and Software

The objective of this paper is to present a systematic procedure to support environmental engineers during the evaluation of alternative options, identifying both, the strong and weak points of their decisions. The evaluation of alternative options in the design of environmental systems is complex because several objectives must be considered simultaneously (e.g. environmental, technical, economical, legal), i.e. the problem is multicriteria. The systematic procedure presented consists of three steps: 1) multicriteria decision analysis (MCDA), where the best alternative is selected among the most promising options by evaluating the degree of accomplishment of several design objectives; 2) sensitivity analysis, where multidimensional …

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

An Efficient Algorithmic Framework For Environmental Modeling, U. Diwekar Jul 2006

An Efficient Algorithmic Framework For Environmental Modeling, U. Diwekar

International Congress on Environmental Modelling and Software

Environmental systems often involve nonlinear models, continuous as well discrete decisions, and multiple objectives. Uncertainties are inherent in these models increasing the complexity of decision making further. This paper presents an efficient algorithmic framework for environmental decision making for large scale systems involving multiple objectives in the face of uncertainties.

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

Nesting Genetic Algorithms To Solve A Robust Optimal Experimental Design Problem, Dirk J. W. De Pauw, Peter A. Vanrolleghem Jul 2006

Nesting Genetic Algorithms To Solve A Robust Optimal Experimental Design Problem, Dirk J. W. De Pauw, Peter A. Vanrolleghem

International Congress on Environmental Modelling and Software

When calibrating a (dynamic) model, one is often faced with a lack of information-rich data. Without such data, there is little hope in obtaining accurate parameter estimates. In order to improve the situation, optimal experimental design for parameter estimation (OED-PE) can be employed. The main drawback of the classical OED-PE methodology is that values for the model parameters need to be provided in order to obtain an optimal design. If the values of the model parameters are highly uncertain, robust OED-PE should be preferred, yielding a design which guarantees a certain information content given the parameter uncertainty. This approach adds …

Go to article

Comparison Of Linear And Non-Linear Pls Methods For Soft-Sensing Of An Sbr For Nutrient Removal, K. Villez, D. S. Lee, C. Rosen, Peter A. Vanrolleghem Jul 2006

Comparison Of Linear And Non-Linear Pls Methods For Soft-Sensing Of An Sbr For Nutrient Removal, K. Villez, D. S. Lee, C. Rosen, Peter A. Vanrolleghem

International Congress on Environmental Modelling and Software

Despite of promising results in research, advanced control strategies fail to gain trust in wastewater treatment practice. Due to the sensitivity of the biological processes to disturbances, operators are often unable to find the causes of faults due to the lack of effective real-time on-line monitoring. Strategies for on-line monitoring are therefore essential to enhance biological process control. Therefore, a suitable multivariate soft-sensor is desired for fault detection and control for a pilot-scale sequencing batch reactor (SBR) system to allow effluent quality to be estimated well before off-line analysis is finished. For this purpose, several multivariate methods are available, including …

Go to article

The Role Of Artificial Neural Network Models In Developing A Regional Wastewater Reclamation Facility For Beaufort, Sc, Usa, Paul A. Conrads, Edwin Roehl, William Martello, Edward Saxon Jul 2006

The Role Of Artificial Neural Network Models In Developing A Regional Wastewater Reclamation Facility For Beaufort, Sc, Usa, Paul A. Conrads, Edwin Roehl, William Martello, Edward Saxon

International Congress on Environmental Modelling and Software

Beaufort and Jasper Counties are two rapidly growing coastal counties in South Carolina. According to the 2000 census, the region grew by 40 percent during the preceding 10 years. The population growth has increased the quantity of wastewater in the area. The Beaufort River is a complex tidal river system that is home to shellfish grounds, fisheries nursery habitats, and extensive recreation by the local community. The river also serves as receiving water for treated wastewater from military and civilian wastewater reclamation facilities (WRF). Although not uncommon for coastal areas, the river is on the South Carolina list of impaired …

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

Data Mining And Image Segmentation Approaches For Classifying Defoliation In Aerial Forest Imagery, K. Fukuda, P. A. Pearson Jul 2006

Data Mining And Image Segmentation Approaches For Classifying Defoliation In Aerial Forest Imagery, K. Fukuda, P. A. Pearson

International Congress on Environmental Modelling and Software

Experimental data mining and image segmentation approaches are developed to add insight towards aerial image interpretation for defoliation survey procedures. A decision tree classifier generated with a data mining package, WEKA [Witten and Frank, 2005], based on the contents of a small number of training data points, identified from known classes, is used to predict the extents of regions containing different levels of tree mortality (severe, moderate, light and non attack) and land cover (vegetation and ground surface). This approach is applicable to low quality imagery without traditional image pre-processing (e.g., normalization or noise reduction). To generate the decision tree, …

Go to article

Uncertainty Management, Spatial And Temporal Reasoning, And Validation Of Intelligent Environmental Decision Support Systems, Miquel Sànchez-Marrè, Karina Gibert, Rick Sojda, Jean-Philippe Steyer, Peter Struss, Ignasi Rodríguez-Roda Jul 2006

Uncertainty Management, Spatial And Temporal Reasoning, And Validation Of Intelligent Environmental Decision Support Systems, Miquel Sànchez-Marrè, Karina Gibert, Rick Sojda, Jean-Philippe Steyer, Peter Struss, Ignasi Rodríguez-Roda

International Congress on Environmental Modelling and Software

There are inherent open problems arising when developing and running Intelligent Environmental Decision Support Systems (IEDSS). During daily operation of IEDSS several open challenge problems appear. The uncertainty of data being processed is intrinsic to the environmental system, which is being monitored by several on-line sensors and off-line data. Thus, anomalous data values at data gathering level or even uncertain reasoning process at later levels such as in diagnosis or decision support or planning can lead the environmental process to unsafe critical operation states. At diagnosis level or even at decision support level or planning level, spatial reasoning or temporal …

Go to article

Helping Children To Be Lifelong Learners, Don Pearson, Ann Pearson Jul 2006

Helping Children To Be Lifelong Learners, Don Pearson, Ann Pearson

Religious Educator: Perspectives on the Restored Gospel

No abstract provided.

Go to article

A Model For Investment Decision Support Based On Multicriteria Analysis, Irina Glazyrina Jul 2006

A Model For Investment Decision Support Based On Multicriteria Analysis, Irina Glazyrina

International Congress on Environmental Modelling and Software

The conventional implementation of polluter pays principle (PPP) in many countries is based on the use of an environmentaltax, which is determined proportionally to the amount of emissions of the polluting substances. Using aspecific mathematical model this study shows that this practice is not adequate for the real negative impact if thepollutant accumulates to a stock in the environment. Moreover, in many cases there is a danger of an unavoidableconflict between the interests of society as a whole and the interests of private business, generated by these proceduresof PPP implementation. This paper also presents a mathematical formula (obtained as an …

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

Integrated Assessment Of Agricultural And Environmental Policies – Towards A Computerized Framework For The Eu (Seamless-If), Martin Van Ittersum, Frank Ewert, Johanna Alkan Olsson, Erling Andersen, Irina Bezlepkina, Floor Brouwer, Marcello Donatelli, Guillermo Flichman, Thomas Heckelei, Lennart Olsson, Alfons Oude Lansink, Andrea-Emilio Rizzoli, Tamme Van Der Wal, Jacques Wery Jul 2006

Integrated Assessment Of Agricultural And Environmental Policies – Towards A Computerized Framework For The Eu (Seamless-If), Martin Van Ittersum, Frank Ewert, Johanna Alkan Olsson, Erling Andersen, Irina Bezlepkina, Floor Brouwer, Marcello Donatelli, Guillermo Flichman, Thomas Heckelei, Lennart Olsson, Alfons Oude Lansink, Andrea-Emilio Rizzoli, Tamme Van Der Wal, Jacques Wery

International Congress on Environmental Modelling and Software

Agricultural systems continuously evolve and are forced to change as a result of a range of global and local driving forces. Agricultural and environmental policies are increasingly designed to contribute to the sustainability of agricultural systems and to enhance contributions of agricultural systems to sustainable development at large. The effectiveness and efficiency of such polices in realizing desired contributions could be greatly enhanced if it were possible to perform ex-ante assessments. The European Commission has recently introduced impact assessment of its policies as an essential step in policy development. This paper presents the design and first prototype of a computerized …

Go to article

Incorporating Qualitative Indicators To Support River Managers; Application Of Fuzzy Sets, J. A. E. B. Janssen, Jean-Luc De Kok, A. Y. Hoekstra, R. M. J. Schielen Jul 2006

Incorporating Qualitative Indicators To Support River Managers; Application Of Fuzzy Sets, J. A. E. B. Janssen, Jean-Luc De Kok, A. Y. Hoekstra, R. M. J. Schielen

International Congress on Environmental Modelling and Software

In evaluation of river management strategies it is generally difficult to deal with the loosely structured and uncertain information at hand. Due to the increasing number of interests and objectives involved in river management it becomes more important to find a way to deal with such information. This paper explores to what extent fuzzy set theory can help in the modelling of relations between river management measures and their effects. The authors conclude that fuzzy logic can provide a valuable contribution because of the relative transparency of the method, the possibility to include qualitative knowledge and the incorporation of uncertainty. …

Go to article

State Of The Art In Methods And Software For The Identification, Resolution And Apportionment Of Contamination Sources, Roma Tauler, Pentti Paatero, Cliff Spiegelman, Eun Sug Park, Richard L. Poirot, Philip Hopke, Ronald C. Henry Jul 2006

State Of The Art In Methods And Software For The Identification, Resolution And Apportionment Of Contamination Sources, Roma Tauler, Pentti Paatero, Cliff Spiegelman, Eun Sug Park, Richard L. Poirot, Philip Hopke, Ronald C. Henry

International Congress on Environmental Modelling and Software

Current approaches and recent developments and software related with multivariate factor analysis and related methods in the analysis of environmental data for the identification, resolution and apportionment of contamination sources are discussed and compared

Go to article

Weap Water Evaluation And Planning System, Jack Sieber Jul 2006

Weap Water Evaluation And Planning System, Jack Sieber

International Congress on Environmental Modelling and Software

WEAP is a microcomputer tool for integrated water resources planning. It provides a comprehensive, flexible and user-friendly framework for policy analysis. A growing number of water professionals are finding WEAP to be a useful addition to their toolbox of models, databases, spreadsheets and other software. This introduction summarizes WEAPΥs purpose, approach and structure. A detailed technical description is available in a separate publication, the WEAP User Guide.

Go to article

A New Raster-Based Spatial Modelling System: 5d Environment, S. Mazzoleni, F. Giannino, M. Mulligan, D. Heathfield, M. Colandrea, M. Nicolazzo, M. D'Aquino Jul 2006

A New Raster-Based Spatial Modelling System: 5d Environment, S. Mazzoleni, F. Giannino, M. Mulligan, D. Heathfield, M. Colandrea, M. Nicolazzo, M. D'Aquino

International Congress on Environmental Modelling and Software

The functional description of natural systems requires the representation of different classes of processes including chemical, biochemical, and physical functions, with or without their spatial representation. On the other hand, there are several cases where a realistic representation of the process dynamics needs a spatially explicit implementation of the model (eg. hydrological flows, fire propagation, pollution diffusion, etc.). In more general terms, and for different scientific fields, scaling problems and the issue of linking dynamic and spatial processes require an integrated logic and appropriate software solutions. Different tools aimed at implementing spatial modelling capability (PCRaster, SME, SimARC) have not yet …

Go to article

Modeling Short-Term Epidemics And Intervention Strategies In Cities, Valeriy Perminov, M. Kornilina Jul 2006

Modeling Short-Term Epidemics And Intervention Strategies In Cities, Valeriy Perminov, M. Kornilina

International Congress on Environmental Modelling and Software

Individual-based model (IBM) for simulation of urban influenza epidemic is constructed. In comparison with the past similar models the proposed model has new features: 1)it bases on a real demographical and social infrastructure statistical data; 2)its contacts network is built up with the help of daily routines of different age and social groups of residents. Test simulations were carried out with the use of demographical data on the population of Dresden (Germany). The results obtained showed that the proposed model can be used for the simulation of different epidemics and intervention strategies to contain epidemic or to weaken its consequences.

Go to article

Learning A Rendezvous Task With Dynamic Joint Action Perception, Nancy Fulda, Dan A. Ventura Jul 2006

Learning A Rendezvous Task With Dynamic Joint Action Perception, Nancy Fulda, Dan A. Ventura

Faculty Publications

Groups of reinforcement learning agents interacting in a common environment often fail to learn optimal behaviors. Poor performance is particularly common in environments where agents must coordinate with each other to receive rewards and where failed coordination attempts are penalized. This paper studies the effectiveness of the Dynamic Joint Action Perception (DJAP) algorithm on a grid-world rendezvous task with this characteristic. The effects of learning rate, exploration strategy, and training time on algorithm effectiveness are discussed. An analysis of the types of tasks for which DJAP learning is appropriate is also presented.

Go to article

Properties Of Conductance And Inhibition Of Proton Channels: M2 From Influenza A Virus And Fo From Escherichia Coli Atp Synthase, Jeffrey C. Moffat Jun 2006

Properties Of Conductance And Inhibition Of Proton Channels: M2 From Influenza A Virus And Fo From Escherichia Coli Atp Synthase, Jeffrey C. Moffat

Theses and Dissertations

Proton channels are essential for many of the processes of life. The influenza A viral protein M2 is responsible for sensing the conditions necessary for viral RNA release. The proton-translocating FoF1 ATPase (ATP synthase) uses a proton gradient to drive adenosine triphosphate (ATP) synthesis. We have directly measured proton uptake in vesicles containing reconstituted M2 or FO by monitoring external pH after addition of valinomycin to vesicles with 100-fold diluted external [K+]. This proton flux assay was utilized to quantify proton flux through single M2 and Fo channels. Contrary to previous reports, proton uptake by M2 was not significantly altered …

Go to article

First Prev Next Last