M Parameter Stud 16888 E77 Select the best result for each factor Expt Factor Observation Compare n1, n2, n D →A A1 B1 C1 D1 A2 B1 C1 D1 2. Compare n1, n4, n5 n2 123456789 B A3 B1 C1 D1 A1 B2 C1 D1 3. Compare n1, n6,n7 C Al C1 D1 n5 Al B1 C2 D1 4. Compare n1, na D Al B1 C3 D1 A1 B1 C1 D2 Best design"is Al C1 D3 A,B*,C*,D* Does not capture interaction between variables C Massachusetts Institute of Technology - Prof de Weck and Prof Willcox Engineering Systems Division and Dept of Aeronautics and Astronautics
11 © Massachusetts Institute of Technology - Prof. de Weck and Prof. Willcox Engineering Systems Division and Dept. of Aeronautics and Astronautics Parameter Study Parameter Study • Select the best result for each factor Expt Factor No. AB C D Observation D1 K1 K 2 K 3 K 4 K 5 K 6 K 7 K 8 K 9 D1 D1 D1 D1 D1 D1 D2 D3 C1 C1 C1 C1 C1 C2 C3 C1 C1 4 A1 B2 5 A1 B3 6 A1 B1 7 A1 B1 8 A1 B1 1 A1 B1 2 A2 B1 3 A3 B1 9 A1 B1 1. Compare K1, K 2, K 3 A* 2. Compare K1, K 4, K 5 B* 3. Compare K1, K 6, K 7 C* 4. Compare K1, K 8, K 9 D* “Best design” is A*,B*,C*,D* • Does not capture interaction between variables
One at a Time 16888 E77 Change first factor, all others at base value If output is improved, keep new level for that factor Move on to next factor and repeat n factors Expt Factor No D 1+m(-1) A1 C1 D1 evaluations I levels 2 B1 C1 D1 A3 B1 C1 D1 4 factors 3 levels each A C1 C1 D1 1+n(1-1)= 6 B C2 D1 7 B D1 B D2 1+4(3-1)=9 expts D3 Result depends on order of factors o Massachusetts Institute of Technology-Prof de Weck and Prof Willcox Engineering Systems Division and Dept of Aeronautics and Astronautics
12 © Massachusetts Institute of Technology - Prof. de Weck and Prof. Willcox Engineering Systems Division and Dept. of Aeronautics and Astronautics One At a Time One At a Time • Change first factor, all others at base value • If output is improved, keep new level for that factor • Move on to next factor and repeat Expt Factor No. AB C D C1 D1 D1 D1 D1 D1 D1 D1 D2 D3 C1 C1 C1 C1 C2 C3 C* C* 4 A* B2 5 A* B3 6 A* B* 7 A* B* 8 A* B* 1 A1 B1 2 A2 B1 3 A3 B1 9 A* B* n factors l levels 1+n(l-1) evaluations 4 factors, 3 levels each: 1+n(l-1) = 1+4(3-1) = 9 expts • Result depends on order of factors