Alternative Designs  Why?  Whole or portion?  Expand the solutions

Design Process

So many choices…

Decision Process  Use the COWS method  C - Criteria. Develop a hierarchy of decision (design) criteria, also known as decision model. Develop a hierarchy of decision (design) criteria, also known as decision model.  O - Options. Identify options, also called solutions or alternatives. The alternatives are the different ideas developed during concept generation. All concepts should be compared at the same level of generalization and in similar language. Identify options, also called solutions or alternatives. The alternatives are the different ideas developed during concept generation. All concepts should be compared at the same level of generalization and in similar language.  W - Weights. Assign a weight to each criterion based on its importance in the final decision. Assign a weight to each criterion based on its importance in the final decision.  S - Scores. Rate each option on a ratio scale by assigning it a score or rating against each criterion. Evaluated as being better (+), the same (S), or worse (-). If it is impossible to make a comparison, more information should be developed. Rate each option on a ratio scale by assigning it a score or rating against each criterion. Evaluated as being better (+), the same (S), or worse (-). If it is impossible to make a comparison, more information should be developed.

Decision Process  Establishing an evaluation team (include advisor, other customers, experts), and setting up a matrix of evaluation criteria versus alternative designs.  Scoring matrix usually associated with a form of prioritization matrix. Usually, the options are scored relative to criteria using a symbolic approach (one symbol for better than, another for neutral, and another for worse than baseline).  These get converted into scores and combined in the matrix to yield scores for each option. Effective for comparing alternative concepts, Effective for comparing alternative concepts, Scores concepts relative to one another, Scores concepts relative to one another, Iterative evaluation method, and Iterative evaluation method, and Most effective if each member of a design team performs it independently and results are compared. Most effective if each member of a design team performs it independently and results are compared.

Decision Matrix

Waste Treatment Treatment Alternatives

Fermentation Reactor Options % BATCHCONTINUOUSRECYCLE Capital cost Operating cost Yield Safety Flexibility

Ethanol Dehydration Options % AZEOTROPIC DISTILLATION DESSICANTSMOLECULAR SIEVE Capital cost Operating cost Ease of use Safety Process time

Irrigation Decision Matrix Grading Criteria% Overhead Sprinkler Irrigation Drip Irrigation Conservation of Water30525 Complete Coverage of Area Continuity of Water107 Power Required to Operate Cost1512 Ease of Installation1098 Total %

Extraction (Decision Matrix)

Analyzation and Selection of Various Immobilization Technologies

QFD – Quality Function Deployment House of Quality

8 Steps of Implementation QFD 1. Identify the customers: WHO ARE THEY? 2. Determine the customers’ requirements: WHAT DO THEY WANT? 3. Determine relative importance: WHO VERSUS WHAT 4. Identify and Evaluate the competition: HOW SATISIFIED IS THE CUSTOMER NOW? 5. Generate engineering specifications: HOW WILL THE CUSTOMER BE MET? 6. Relate customers’ requirements to engineering specifications: HOW TO MEASURE WHAT? 7. Set engineering targets: HOW MUCH IS GOOD ENOUGH? 8. Identify relationships between engineering requirements: HOW ARE THE HOWS DEPENDENT ON EACH OTHER?