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What is the real problem? A student and his professor are backpacking in Alaska when a grizzly bear starts to chase them from a distance. They both start running, but it’s clear that eventually the bear will catch up with them. The student takes off his backpack, gets his running shoes out, and starts putting them on. His professor says, “You can’t outrun the bear, even in running shoes!” The student replies, “I don’t need to outrun the bear; I only need to outrun you!”
Problem Formulation This is the most important step in the process. For proper formulation: Focus on function Example: “enhance communication between all parties” versus “design a better telephone system”.
Problem Formulation • Avoid giving specific solution. This would limit the search for solutions. • Define the “real problem” not the “perceived problem”.
Example -Needs assessment :Low speed collisions result in too much damage. -Problem Formulation: Design a front bumper that can withstand low speed collision.
Specifications Additional requirements and limitations may modify the statement to read: Design an inexpensive front bumperso the car can withstand a 5 mph head-on collision with a fixed concrete wall without significantly damaging the bumper or other parts of the car. In addition, the bumper must be easily recyclable.
Constraints Constraints: In order to prevent over-riding bumpers in collision between automobiles, the federal government requires that all bumpers be installed 18” up the ground. The weight of the bumper cannot exceed 50 Ib.
The basic types of problems 1. Prediction : calculating a result or predict a system’s behavior by applying equations, physical laws, tools analysis, etc. 2. Explanation: searching for the cause of failure.
Continued … 3. Invention: developing a new and effective solution to a problem. 4. A combination : One make seek to prevent satellites from falling (a problem of invention), but he must first determine the cause for such flight failures (a problem of explanation).
Search for the Problem • When the phenomenon is not known, we need to search for the problem. • Example: what caused the crash of the DC-10 (AA Flight # 191)?
Structuring the Search for the Problem Formulation • Objective(Why?) Focus upon function. • Background (Who? Where?) Who will be served by a solution with the environment in which design is expected to be used?
Structuring the Search for the Problem Formulation … • Methodology (How? When?) Description of the approach that will be used to develop the solution. • Expected results (What?) • Costs
The Statement-Restatement Determine the real problem (in contrast to the stated problem) by varying the emphasis on certain words and phrases in the problem statement. Ask yourself if the focus of the problem itself changed. In what ways? Example: Coating for tablets (pills).
The Statement-Restatement … Determine the actual constraints or boundaries (in contrast to the given or inferred boundaries). One relaxed constraint may have altered the entire focus. Example: using “less than 200 lbs” in place of “less than 100 lbs”
The Statement-Restatement … Identify meaningful goals (in contrast to a set of given goals). Ask yourself if all the stated goals are equally important? Try to prioritize the goals and then focus upon the most critical ones as you rewrite the problem statement. Example: Increase the number of commuters who use public transportation.
The Statement-Restatement … Identify relationship between inputs, outputs, and any unknowns. What are the inputs (materials, people, equipment, money)? What additional data to be collected? The problem statement should then include what is known, what is unknown, and what is sought in a solution.
Other Strategies One strategy for formulating a clear problem statement is the so-called present state-desired state technique. One begins by specifying (as best as one can) the present or problem state (PS), and then the desired or solution state (DS). One then modifies both the PS and the DS until there is a satisfactory correlation between the two. The Dunker Diagram is often used as a graphical approach to the PS/DS technique
The Dunker Diagram is often used as a graphical approach to the PS/DS technique. The Dunker Diagram presents three classes of solutions.
General Solutions come in two forms: • Those that require some action to be taken to achieve the desired state. • Those that transform the desired state until it matches the present state. • Functional Solutions are derived from the general solutions without regard to feasibility. • Specific Solutions are feasible solutions derived from the functional solution list.
The Dunker Diagram can also be used without the present state - desired state formulation Problem Positive General Solution Negative General Solution Functional Solutions Functional Solutions Specific Solutions Specific Solutions
Example of Dunker Diagram Toasty O’s was one of the hottest selling cereals when it first came on the market. After several months the sales dropped. Surveys determined the customer’s dissatisfaction: Cereal was stale when purchased. Needs Assessment: Cereal is stale.
Example Continued …. • Perceived problem: We do not get the product to market fast enough. • Solution: Streamline the production process to get the cereal on the store shelves faster thus ensuring fresh product.
Dunker Diagram Cereal not getting to market fast enough to maintain freshness Get cereal to market faster Make it OK for cereal NOT to get to market faster Functional Solutions Functional Solutions Specific Solutions Specific Solutions
Homework:Chapter 3Structuring the search for the problem.Pages 87-114