environmental modeling Articles
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Space, economy and the environment: Danish studies
The paper makes a brief presentation of selected research in the field of space, economy and the environment, as of 1998. The paper first reviews the reasons for strong Danish interest in these issues. Then, spatial issues are reviewed and Danish studies presented. In particular, distinction is made between environment-economy models as pre-models which treat environmental change and regulation ...
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New Project Wins in Africa
WKC Group are pleased to announce the award of two new contracts in Africa, Guinea and Namibia Work will begin immediately and will involve several types of environmental modelling and monitoring services. These new projects represent new geographies for WKC within the African continent, testimony to the concerted efforts made to increase presence in one of the most exciting and quickly growing ...
By WKC Group
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Probability density estimation in stochastic environmental models using reverse representations
The estimation of probability densities of variables described by stochastic differential equations has long been done using forward time estimators, which rely on the generation of forward in time realizations of the model. Recently, an estimator based on the combination of forward and reverse time estimators has been developed. This estimator has a higher order of convergence than the classical ...
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Improved environmental multimedia modeling and its sensitivity analysis
Modeling of multimedia environmental issues is extremely complex due to the intricacy of the systems with the consideration of many factors. In this study, an improved environmental multimedia modeling is developed and a number of testing problems related to it are examined and compared with each other with standard numerical and analytical methodologies. The results indicate the flux output of ...
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Chapter 5: Energy-economy-environmental models with special reference to CO2 emission control
As a consequence of the modelling exercise in Chapters 2–4, the question arises as to how these models could be extended and improved for large-scale use in the analysis of more detailed, more specific policy options. Before we suggest extensions, generalisations and ramifications of such models for more policy-directed use, we review the state of the art of energy modelling and attempt to derive ...
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On the numerical asymmetry in calculating Coriolis terms through the splitting method in a mesoscale model
The asymmetry in calculating the Coriolis terms by Marchuk's splitting method is discussed. It was found that although some asymmetry is required for linear stability, this asymmetry should be kept to a minimum. Otherwise, for instance, if the diffusion terms are calculated in between the Coriolis terms in the u and v equations of motion, one gets cross-isobaric low-level winds, which are ...
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Multi-variable sensitivity and identifiability analysis for a complex environmental model in view of integrated water quantity and water quality modeling
Environmental models are often over-parameterized. A sensitivity analysis can identify influential model parameters for, e.g. the parameter estimation process, model development, research prioritization and so on. This paper presents the results of an extensive study of the Latin-Hypercube–One-factor-At-a-Time (LH-OAT) procedure applied to the Soil and Water Assessment Tool (SWAT). The LH-OAT is ...
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Environmental modelling for blue collars
Model complexity and the breakpoint of diminishing returns; physical vs. conceptual modelling; the relevance and limits of the heuristic solutions; screening vs. analytical modelling; perceptions of uncertainties, calibration and sensitivity analysis; and the ethics in modelling – are only a few issues outstanding in the volatile philosophy of the environmental modelling. Glossing on ...
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A grey-encoded hybrid accelerating genetic algorithm for parameter optimisation of environmental models
A new method, grey-encoded hybrid accelerating genetic algorithm, is presented for the parameter optimisation of environmental models. With the shrinking of searching range, the method gradually directs to optimal result with the excellent individuals obtained by grey genetic algorithm embedding Nelder-Mead simplex searching operator. The convergence theorem is given for guaranteeing the global ...
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A survey of material flows in economic models
Various types of economic model address environmental problems. This article examines whether these can be applied to the analysis of material flows. It is important to know which types of model are most suitable to deal with particular economic, environmental or physical aspects of material flows. For this purpose five main categories of models are considered, namely economic models of natural ...
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Application of model trees and other machine learning techniques for algal growth prediction in Yongdam reservoir, Republic of Korea
A promising new approach for eco-environmental modelling, such as algal growth prediction, is the data-driven modeling using machine learning techniques: an artificial neural network (ANN) being a typical method. Another method growing in popularity, based on the M5 model tree (MT) algorithm, is the use of piecewise linear regression models at the leaf nodes of the tree. M5 MTs using partial ...
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Environmental effects of transport: a model of optimal pricing and investment for the UK
This paper models the effects of imposing efficient pricing on interurban passenger travel in the United Kingdom and passenger travel in London. Both the internal and external costs of the main modes are estimated. The resulting efficient prices are used to predict the changes in demand for each mode, together with implied tax revenues, operators' aggregate surplus or deficit, and the implied ...
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State of the art of air pollution models, needs and trends
This paper summarises the results of the investigations within task MA3-2 carried out by the European Topic Centre on Air Quality. The main aim of this task is to describe the state of the art of air pollution models, with special emphasis on needs for model application and trends in model development. From the results it can be inferred to what extent the needs are met by available models and ...
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Different splitting techniques with application to air pollution models
Splitting techniques are commonly used when large-scale models, which appear in different fields of science and engineering, are treated numerically. Four types of splitting procedures are defined and discussed. The problem of the choice of a splitting procedure is investigated. Several numerical tests, by which the influence of the splitting errors on the accuracy of the results is studied, are ...
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What's in a Model? More Than You Think
Untitled Document The use of complex mathematical models is central to the U.S. Environmental Protection Agency’s (EPA’s) decision-making process. It is generally impractical to obtain measured data to support the many scenarios involved in environmental decision-making. Thus, EPA relies heavily upon models for a host of applications, including estimating ...
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On numerical solver selection and related uncertainty terminology
Mathematical models provide insight into numerous biological, physical and chemical systems. They can be used in process design, optimisation, control and decision support, as acknowledged in many different fields of scientific research. Mathematical models do not always yield reliable results and uncertainty should be taken into account. At present, it is possible to identify some factors ...
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Regulatory dispersion modelling in Denmark
In Denmark, the basic model for environmental impact assessments is the so-called OML model. The OML model is a Gaussian model, but in contrast to conventional regulatory models its physical description is not based on the traditional discrete stability categories. Instead, the model uses basic scaling parameters such as friction velocity, the Monin-Obukhov length, and the convective velocity ...
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Models of internationalisation: the New Zealand experience
This paper examines the models of internationalisation adopted by 30 firms from New Zealand. Analysis of the internationalisation model is based on five key dimensions: firm sector and size; international market scope; market entry and servicing strategies; and speed of internationalisation. Drivers and constraints to internationalisation are also considered in the analysis. Evaluation of these ...
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Towards use of grids in environmental research, management and policy
The emerging technology of the grid will enable distributed "virtual organisations" to flexibly share resources including data, software, hardware and expertise. Potential applications in urban air quality illustrate that in addition to underpinning scientific research, grid technology can contribute strongly to environmental monitoring, decision-making and policy-making. Amongst factors that ...
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Aid, economic growth and environmental sustainability: rich-poor interactions and environmental choices in developing countries
Rich-poor interactions complicate the search for a stable Environmental Kuznets Curve (an "inverted U" relationship between income per-capita and environmental degradation). We show that aid from richer to poorer countries to support investments in environment, in either of two forms, alters the income-environment relationships that otherwise exist, lowering levels of degradation in the poorer ...
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