Yes, you fixed the grammar for the compound verb, but that compound verb construction was awkward.
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Educational Ministries, Inc. 1998</ref>
Educational Ministries, Inc. 1998</ref>
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Models can be empirically found, or derived from fundamental laws. A good model has a well-defined domain of validity, in which it leads to unambiguous, self consistent results. Ideally it is easy to evaluate. To adaption of a model to a specific problem instance is done by model parameters, which can be defined/measured independently or left as free parameters to fit the model to a realistic situation. A large number of free parameters makes it difficult to assess the validity of the model without independent knowledge.
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Models can be empirically found, or they can be derived from fundamental laws. A good model has a well-defined domain of validity, in which it leads to unambiguous, self-consistent results. Ideally it is easy to evaluate. To adaption of a model to a specific problem instance is done by model parameters, which can be defined/measured independently or left as free parameters to fit the model to a realistic situation. A large number of free parameters makes it difficult to assess the validity of the model without independent knowledge.
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You can also make a model simply by fiddling around with the data, as NASA did when studying the erosion of O-rings used in the [[space shuttle]]:
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One can also make a model simply by fiddling around with the data, that is, "curve fitting" without a fundamental understanding of the phenomenon, as NASA did when studying the erosion of O-rings used in the [[space shuttle]]:
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:A mathematical model was made to calculate erosion. This was a model based not on physical understanding but on empirical curve fitting.<ref>[http://www.ralentz.com/old/space/feynman-report.html Feynman's Appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident]</ref>
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:A mathematical model was made to calculate erosion. This was a model based not on physical understanding but on empirical curve fitting.<ref> [http://www.ralentz.com/old/space/feynman-report.html Feynman's Appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident]</ref>