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Model-Based Analysis for Qualitative Data: An Application in Drosophila Germline Stem Cell Regulation
Figure 2
Estimation of representative parameters.
A) Diagram of fitness quantification by Optimal Scaling. Images are mapped to qualitative data (left, image reproduced/adapted from [58]). Surrogate data (blue 
) are chosen to best fit model outputs (green line) within intervals that match data (shaded boxes). Intervals are additionally constrained by minimum gaps and sizes. B) Diagram of the global optimization procedure. (Left) Parameter space is screened by sparse grid (
) and pseudo-random sampling (
)A. Color indicates cost (blue: low, red: high). (Right) Multiple gradient-based searches are started from the best samples (blue 
), and find local minima (blue 
). Finding all minima is not guaranteed (no solution in upper right quadrant). C) Diagram of the multiobjective optimization procedure. (Left and center) Example Pareto fronts (solid line) for objectives 
and 
, showing Anchor points (
and 
), and Utopian points (
). (Right) Example solution via the modified NNC method, showing: Anchor points (
), Utopian (
), gradient search starts (
), normal constraints (dashed line), gradient solutions (
).
doi: https://doi.org/10.1371/journal.pcbi.1003498.g002