tailieunhanh - Business process improvement_9

Tham khảo tài liệu 'business process improvement_9', kỹ thuật - công nghệ, điện - điện tử phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Single response Path of steepest ascent Two main decisions search direction and length of step There are two main decisions an engineer must make in Phase I 1. determine the search direction 2. determine the length of the step to move from the current operating conditions. Figure shows a flow diagram of the different iterative tasks required in Phase I. This diagram is intended as a guideline and should not be automated in such a way that the experimenter has no input in the optimization process. Flow chart of iterative search process FIGURE Flow Chart for the First Phase of the Experimental Optimization Procedure http div898 handbook pri section5 2 of 6 5 1 2006 10 31 05 AM Single response Path of steepest ascent Procedure for Finding the Direction of Maximum Improvement The direction Suppose a first-order model like above has been fit and provides a useful approximation. As of steepest long as lack of fit due to pure quadratic curvature and interactions is very small compared to ascent is the main effects steepest ascent can be attempted. To determine the direction of maximum determined by improvement we use the gradient of the fitted 1. the estimated direction of steepest ascent given by the gradient of y if the objective is model to maximize Y 2. the estimated direction of steepest descent given by the negative of the gradient of y if the objective is to minimize Y. The direction of steepest ascent depends on the scaling convention -equal variance scaling is recommended Solution is a simple equation The direction of the gradient g is given by the values of the parameter estimates that is g Ai b2 . bk . Since the parameter estimates b1 b2 . bk depend on the scaling convention for the factors the steepest ascent descent direction is also scale dependent. That is two experimenters using different scaling conventions will follow different paths for process improvement. This does not diminish the general .