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  • A steady-state model of ecological hierarchy

    Creator:
    Thompson, Grant Garrison
    Abstract:
    A generalized mathematical model of ecosystems is developed. The model begins with the general class of systems known as state-determined systems, in which the time-derivative of each state variable is a function of some subset of the set of all system state variables and .environmental parameters. A formal basis is...
    Resource Type:
    Dissertation
    Full Text:
    Abstract approved: William J. Lis; A generalized mathematical model of ecosystems is developed. The

  • Qualitative analysis of the community matrix

    Creator:
    Dambacher, Jeffrey M.
    Abstract:
    This work sets forth a reformulation of Levins' loop analysis for the qualitative modeling of complex dynamical systems. Relationships between members of ecological communities can be analyzed through a qualitatively specified community matrix, whereby +1, -1, or 0 represent effects of one species upon another. A contribution is made to...
    Resource Type:
    Dissertation

  • Predicting the stability, equilibrium response, and nonequilibrium dynamics of ecological systems

    Creator:
    Hosack, Geoffrey R.
    Abstract:
    In this dissertation, new theory and its applications are developed to predict three properties of complex ecological communities: stability, equilibrium response, and non-equilibrium dynamics. First, a graph-theoretic analysis identifies the interconnections in a complex ecosystem that promote or diminish stability (Chapter 2). The hierarchy of interactions that influences stability and...
    Resource Type:
    Dissertation
    Full Text:
    affects the stability of the community. The mathematical derivation of the sensitivity weight matrices

  • Sensitivity analysis as "propagation of error" and model validation

    Creator:
    Overton, W. Scott
    Abstract:
    Conclusion: The first part of this note deals with problems of propagation of error and the latter part with questions commonly identified as "model validation" questions. It is concluded that all validation questions can be resolved into two parts: (1) strategic aspects, involving logical and inferential structures and (2) tactical...
    Resource Type:
    Technical Report
    Full Text:
    to validation of model form (structure and specification of mathematical relationships) and

  • Modeling riparian zone processes : biomass production and grazing

    Creator:
    Korpela, Edwin J.
    Abstract:
    Seasonal trends in forage production and environmental parameters for five plant community types within a northeastern Oregon riparian zone were described and modeled using correlation and path analysis. Wet meadows produced the greatest amount of herbage biomass, followed by moist bluegrass meadows, gravel bars, forests and dry bluegrass meadows. Trends...
    Resource Type:
    Dissertation
    Full Text:
    Community Designation 11 Field Sampling 11 Path Analysis 13 The Theoretical Model 17 Results and Discussion

  • Creating, Understanding and Applying Machine Learning Models of Multiple Species

    Creator:
    Griffioen, Arwen Twinkle E.
    Abstract:
    Many problems in ecology and conservation biology can be formulated and solved using machine learning algorithms for multi-label classification. This dissertation addresses three topics related to predicting the distributions of multiple species. It improves existing methods and proposes a new modeling paradigm to address the multi-species, multi-label problem. The first...
    Resource Type:
    Dissertation
    Full Text:
    .............................................................................. 24 The Group Set Community Model (GSCM

  • Development of a model for context evaluation of community college competency-based curricula

    Creator:
    Noonan, Arthur Barry
    Abstract:
    Purpose of the Study: The purpose of this study was to develop and field test a model for context evaluation of objectives used in competency-based curricula at the community college level. The study: 1. Developed a decision and information matrix that identified objectives which should be considered for deletion from...
    Resource Type:
    Dissertation
    Full Text:
    DEVELOPMENT OF A MODEL FOR CONTEXT EVALUATION OF COMMUNITY COLLEGE COMPETENCY-BASED CURRICULA by Arthur

  • A spatially explicit method for determining the effects of watershed scale land use on stream conditions

    Creator:
    Kehmeier, Jonathan W.
    Abstract:
    The primary goal of this research was to identify the impacts that individual agricultural land uses have on fish communities in small streams located in the Willamette Valley of western Oregon. The diverse nature of the land use features of the valley provided a challenging but useful system for the...
    Resource Type:
    Masters Thesis
    Full Text:
    identification of the land use practices that have the greatest impact on stream fish assemblages. A model using