To illustrate significance of U, K, and φ, we perform a simulation experiment. The change of biomarkers is simulated in three cases. The three situations are shown as follows: Single marker changing simulation: Only one marker changes as the gradient.
Multi-marker changing simulation 1: All the markers increase as the gradient. For instance, the gradient is 10%. At this situation, all three markers increase 10%.
Multi-marker changing simulation 2: The first marker increases as the gradient and the other two markers decrease as the gradient. For instance, marker A increases 10% and markers B and C decrease 10%.