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Different types of bones can have different modeling and remodeling thresholds. The modeling threshold of the tibia is about 1500 μStrain (0.15% change of length), while the modeling threshold for parts of the bones of the skull is quite different.
Petrovich theorized a Cybernetic Model for the Servosystem Theory. This theory states that occlusion provides a constantly changing input which influences the horizontally regulated growth of the midface and anterior cranial base. This midface growth then serves as a rate limiting factor for the growth of the mandible.
Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts. Both processes utilize cytokine (TGF-β, IGF) signalling.In osteology, bone remodeling or bone metabolism is a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation).
Each vertebrate species exhibits a distinct duration of bone regeneration and remodeling, and it appears as though there is an inversely proportional relationship between the rate of bone regeneration and the phylogenetic evolution of the animal. [7] Each remodeling period lasts 3–6 months in humans, 3 months in dogs, and 6 weeks in rabbits. [8]
The inverse is true as well: if the loading on a bone decreases, the bone will become less dense and weaker due to the lack of the stimulus required for continued remodeling. [5] This reduction in bone density ( osteopenia ) is known as stress shielding and can occur as a result of a hip replacement (or other prosthesis).
Modeling and simulation (M&S) is the use of models (e.g., physical, mathematical, behavioral, or logical representation of a system, entity, phenomenon, or process) as a basis for simulations to develop data utilized for managerial or technical decision making.
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In any case, users of a model need to understand the assumptions made that are pertinent to its validity for a given use. Building a model requires abstraction. Assumptions are used in modelling in order to specify the domain of application of the model. For example, the special theory of relativity assumes an inertial frame of reference.