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- All Subjects: Human ecology
- Creators: Clark, Geoffrey A.
- Creators: Mayer, Gary R.
Hybrid system models - those devised from two or more disparate sub-system models - provide a number of benefits in terms of conceptualization, development, and assessment of dynamical systems. The decomposition approach helps to formulate complex interactions that are otherwise difficult or impractical to express. However, hybrid model development and usage can introduce complexity that emerges from the composition itself.
To improve assurance of model correctness, sub-systems using disparate modeling formalisms must be integrated above and beyond just the data and control level; their composition must have model specification and simulation execution aspects as well. Poly-formalism composition is one approach to composing models in this manner.
This dissertation describes a poly-formalism composition between a Discrete EVent System specification (DEVS) model and a Cellular Automata (CA) model types. These model specifications have been chosen for their broad applicability in important and emerging domains. An agent-environment domain exemplifies the composition approach. The inherent spatial relations within a CA make it well-suited for environmental representations. Similarly, the component-based nature of agents fits well within the hierarchical component structure of DEVS.
This composition employs the use of a third model, called an interaction model, that includes methods for integrating the two model types at a formalism level, at a systems architecture level, and at a model execution level. A prototype framework using DEVS for the agent model and GRASS for the environment has been developed and is described. Furthermore, this dissertation explains how the concepts of this composition approach are being applied to a real-world research project.
This dissertation expands the tool set modelers in computer science and other disciplines have in order to build hybrid system models, and provides an interaction model for an on-going research project. The concepts and models presented in this dissertation demonstrate the feasibility of composition between discrete-event agents and discrete-time cellular automata. Furthermore, it provides concepts and models that may be applied directly, or used by a modeler to devise compositions for other research efforts.
Some broad generalizations have been made; most work in the region is concerned primarily with descriptive and definitional issues rather than efforts to explain past human behavior or human-environmental interactions. Modern research directed towards understanding human adaptation to different environments remains in its infancy. Grounded in the powerful conceptual framework of evolutionary ecology and utilizing recent methodological advances, this work has shown that shifts in land-use strategies changes the opportunities for social and biological interaction among Late Pleistocene hominins in western Eurasia, bringing with it a plethora of important consequences for cultural and biological evolution.
I employ, in my Dissertation, theoretical and methodological advances derived from human behavioral ecology (HBE) and lithic technology organization to show how variability in lithic technology can explain differences in technoeconomic choices and land-use strategies of Late Pleistocene foragers in Romanian Carpathians Basin and adjacent areas. Set against the backdrop of paleoenvironmental change, the principal questions I addressed are whether or not technological variation at the beginning of the Upper Paleolithic can account for fundamental changes at its end.
The analysis of the Middle and Upper Paleolithic strata, from six archaeological sites, shows that the lithic industries were different not because of biocultural differences in technological organization, landuse strategies, and organizational flexibility. Instead the evidence suggests that technoeconomic strategies, the intensity of artifact curation and how foragers used the land appear to have been more closely related to changing environmental conditions, task-specific activities, and duration of occupation. This agrees well with the results of studies conducted in other areas and with those predicted from theoretically-derived models based on evolutionary ecology. My results lead to the conclusion that human landuse effectively changes the environment of selection for hominins and their lithic technologies, an important component of the interface between humans and the natural world. Foragers move across the landscape in comparable ways in very different ecological settings, cross-cutting both biological morphotypes and prehistorian-defined analytical units.