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Physical Sciences and Mathematics Commons

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Sustainability

Portland State University

Systems Science Faculty Publications and Presentations

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Full-Text Articles in Physical Sciences and Mathematics

System Dynamics Implementation Of A Model Of Population And Resource Dynamics With Adaptation, Takuro Uehara, Yoko Nagase, Wayne Wakeland Jun 2012

System Dynamics Implementation Of A Model Of Population And Resource Dynamics With Adaptation, Takuro Uehara, Yoko Nagase, Wayne Wakeland

Systems Science Faculty Publications and Presentations

We build and analyze a dynamic ecological economic model that incorporates endogenous innovation on input substitutability. The use of the system dynamics method allows us to depart from conventional equilibrium thinking and conduct an out-of-equilibrium (adaptation) analysis. Simulation results show that while improvement in input substitutability will expand an economy, this change alone may not improve sustainability measured by indicators such as utility-per-capita and natural resource stock. It could, however, be possible that in combination with other technological progress, improvement in input substitutability will contribute to sustainable development. Sensitivity analysis also indicates a possible complication with the use of exogenous …


A System Dynamics Model Of The Pacific Coast Rockfish Fishery, Wayne Wakeland, Olgay Cangur, Guillermo Rueda, Astrid Scholz Jul 2003

A System Dynamics Model Of The Pacific Coast Rockfish Fishery, Wayne Wakeland, Olgay Cangur, Guillermo Rueda, Astrid Scholz

Systems Science Faculty Publications and Presentations

This paper presents a model of the dynamic behavior of the yellowtail rockfish of the Pacific Coast of the United States. The purpose of the model is to generate endogenously the historical data for fish population, fishing vessels, regulatory parameters, and fish harvest. The model was subjected to a variety of tests to determine its sensitivity to changes in key parameters and initial values, including extreme conditions. Model results indicate that acceptable biological catch and fleet capacity must be adjusted quickly in response to changing conditions, in order to improve fishery sustainability. Additional analysis reinforces the policy of setting the …