Browsing by Subject "simulation model"

Now showing 1 - 3 of 3
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    Classical Swine Fever and Food Security: Modeling the impact of trade restrictions on transboundary animal disease control in U.S. and Canadian swine
    (2019-12) Meyer, Michelle
    Transboundary animal diseases (TADs) such as classical swine fever (CSF) are highly infectious animal diseases that have the potential to easily spread across international borders. TADs present a potential threat to food security and public health, often with severe economic consequences. CSF is a World Organisation for Animal Health notifiable disease that was eradicated from the U.S. in 1978 and Canada in 1963. Re-introduction could have a substantial economic impact and long-lasting repercussions on trade. Therefore, regulatory cooperation of TAD control between the United States Department of Agriculture and the Canadian Food Inspection Agency is one area of focus being explored to facilitate trade and economic growth, while mitigating the economic, public health, or social impacts of potential outbreaks. However, emergency response planning for a TAD outbreak in U.S. and Canadian swine populations has become challenging due to significant changes in the size, structure and connectivity of the swine industry in the last half-century. Epidemic simulation models are one type of tool that can be used to help understand the scope and impact of potential TAD outbreaks as well as evaluate the effectiveness of disease control strategies. This thesis outlines the incremental development of a spatially-explicit, stochastic transboundary epidemic simulation model of CSF between U.S. and Canadian swine farms to examine the epidemiological impact of international trade restrictions following CSF detection and evaluate the use of mutually recognized zones for disease control. Individual animal and herd-level disease parameters (latent, subclinical, incubation and clinical periods) for highly and moderately virulent CSF are developed in Chapter 2. A transboundary model of CSF is developed in Chapter 3 to evaluate the scope and scale of potential CSF outbreaks while varying the index farm location (Iowa, North Carolina, Ontario or Quebec), production type (farrow-to-wean or nursery operation) and CSF virulence level (high or moderate virulence CSF). The transboundary model is used in Chapter 4 to evaluate epidemiologic outcomes of different control policies for swine movements at the U.S. and Canadian border.
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    Methods for Routing Hydrographs Through Open Channels
    (Water Resources Research Center, University of Minnesota, 1972-06) Larson, Curtis L.; Rice, Charles E.
    In this study a simulation model of an open channel system was used to evaluate some existing flood routing methods, observe the effect of different physical variables on flood wave movement, and to develop a simple routing method. The physical, geometric, and hydraulic components of the model were patterned after real-life conditions common to southeastern Minnesota. The dynamic equations of unsteady flow were used to route flood hydrographs through the channel system and outflow hydrographs were generated to achieve the objectives listed above. The method of characteristics with a specified time interval was used to solve the unsteady flow equations. Two simple storage routing methods, the Method A and the Method B were developed and evaluated. Other simple routing methods evaluated include: the Muskingum, the Puls, and the Kinematic Wave. Complete methods evaluated were the Direct and the Explicit. The methods were evaluated by comparing the results by the methods with the generated results. Comparisons were made on the accuracy of the predicted results, the complexity of the method, and the computation time required for a solution. The work reported herein was carried out in partial fulfillment of the requirements for the degree of Doctor of Philosophy, granted to Charles Edward Rice by the University of Minnesota, June 1972.
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    Study of Criteria and Models Establishing Optimum Level of Hydrogeologic Information for Groundwater Basin Management
    (Water Resources Research Center, University of Minnesota, 1975-04) Pfannkuch, Hans-Olaf
    It is shown that information is a structural part of the decision making process. The role of the information gathering process can best be described as Hayes' process to improve preposterior distributions in probability assignments that will serve as basis for decision making processes. Hydrogeologic information is characterized by a low degree of predictability and high variability. The general cost structure of the hydrologic information gathering process is represented in information cost curves which are combined with production cost or opportunity loss curves to give total cost curves. These may display a minimum which is the point of diminishing returns at which exploration activities should be ceased. One of the main unsolved problems is the proper definition of a universally applicable unit of information content. Optimum levels of information can only be established when utility functions can be expressed in monetary terms and give rise to clear objective functions. Three case histories were used to develop guidelines for the design and operation of monitoring systems for special wastes, minimum hydrogeologic information needed in watershed district management, and the need and role of information in the choice and construction of a proposed simulation model for a regional system under complex decision rules.