Nonstationary Analysis of Blast Furnace Through Solution of Inverse Problem and Recurrence Plot

A recurrence plot is a method for directly visualizing, on a two-dimensional surface, information regarding the proximal points and distance between two points created using time delay coordinates from temporal sequence data This method qualitatively captures the nonstationary nature of temporal sequence data. However, as the complexity of phenomena increases, the plotted structure of visualizations using two-dimensional surfaces also becomes complex. This can cause problems when trying to interpret changes in the plotted structure. This paper proposes a method of recurrence plot structural analysis, that is, on the basis of deterministic principles. Furthermore, because the proposed method is applied to a blast furnace, which involves the handling of enormous quantities of high-temperature molten iron as well as complex phenomena accompanying reactions in the gas, liquid and solid phases, direct measurement of the internal states when they are treated as spatial distributions is an extremely difficult process. Thus, this study undertakes an analysis of the principles of the determinable properties underlying the temperature shifts in the thermoelectric couples embedded in the brickwork of the furnace floor.