ECET 4550: Alternate Energy Fall 2011 Laboratory Topic: The Problem to be Solved “Statement of the Problem” Florian Misoc, 2010

Chapter Objectives Identifying and Representing the Client’s Objectives Measurable Quantities Setting Priorities Constrains: Limitations and Delimitations Case Study and Examples Florian Misoc, 2010

Introduction Problem Definition = the most important step in the design process Problem Definition: pre-design phase of design Frame the problem => engineering terms Focus on tasks 1 – 4: 1.Clarify Objectives 2.Establish Metrics for Objectives 3.Identify Constrains 4.Revise Client’s Problem Statement Florian Misoc, 2010

Identifying and Representing the Client’s Objectives Client’s original problem statement: a.Initial statements: brief, general idea b.No hint on: intended market, shape of the product, material to be used, etc. c.Initial statement has limitations: errors, bias, imply solutions d.Clarify what client wants: what potential users need, e.Technological & marketing context Florian Misoc, 2010

Identifying and Representing the Client’s Objectives 1.Errors: incorrect information, faulty and/or incomplete data, mistakes regarding the problem 2.Biases: presumptions about the situation, involving a person’s preference 3.Implied Solution: client’s best guess at solutions, frequently found in the original problem statement (related to bias) Florian Misoc, 2010

Errors of the Design Process Source:

Errors of the Design Process Source:

Errors of the Design Process Source:

Errors of the Design Process Source:

Identifying and Representing the Client’s Objectives: Questions & Brainstorming Two kinds of activity: a.Asking questions of the client/stakeholder, with varying degree of interest in the problem/design b.Brainstorming: group effort to generate, retain, and organize new ideas to solve the problem Florian Misoc, 2010

Identifying and Representing the Client’s Objectives: Asking Questions Questions to understand the scope of the project: a.What features/attributes you desire for …..? b.What do you want this …. to do? c.Are there already …. with similar attributes? Ask also: i.What does it mean? ii.How are you going to do that? iii.Why do you want that? Florian Misoc, 2010

Identifying and Representing the Client’s Objectives: Brainstorming 1.Focus on quantity: maxim quantity = quality. Great number of ideas = greater the chance of effective solution. 2.Withhold criticism: focus on extending or adding to ideas, reserve criticism for a later 'critical stage' of the process 3.Welcome unusual ideas: looking from new perspectives and suspending assumptions (may provide better solutions) 4.Combine and improve ideas: Good ideas = combinations of ideas: slogan "1+1=3” Florian Misoc, 2010

Brainstorming: preliminary / start-up Florian Misoc, 2010

Identifying and Representing the Client’s Objectives: Concept Definitions A.Objective: something toward which effort is directed (an aim/end-of-action) B.Constraint: restricted, compelled to avoid, compelled to perform C.Function: fitness for use, “for which a thing is made-for” D.Means: method used to attain and end Florian Misoc, 2010

Client’s Objectives: Objective Tree Florian Misoc, 2010

Measurable Quantities Six Scale Types: 1.Nominal Scales: distinguish among categories 2.Partially Ordered Scales: hierarchies 3.Ordinal Scales: rank / order 4.Ratio Scales: percentage 5.Interval Scales: reference to a base-point 6.Multidimensional Scale: compounds of other scales Florian Misoc, 2010

Pair-wise Comparison Chart (PCC) Should be applied in constrained “top-down” fashion: 1)Objectives are compared when at the same level (in the objective tree) 2)Higher level objectives: compared first Only “top objectives” need to be ranked “Low level objectives” are ranked ONLY for complex systems Florian Misoc, 2010

Weighted Objectives: American Beverage Company Florian Misoc, 2010 GoalsEnviron. Benign DistributeTasteParent appeal MarketBrandScore Environ. Benign **** Distribute1****11104 Taste10****0001 Parent Appeal 101****002 Market1011****03 Brand11111****5

Weighted Objectives: National Beverage Company Florian Misoc, 2010 GoalsEnviron. Benign DistributeTasteParent appeal MarketBrandScore Environ. Benign **** Distribute0****00101 Taste01****1114 Parent Appeal 010****113 Market0000****00 Brand01001****2

Pair-wise Comparison Chart (PCC) Pair-wise comparison chart for the “ladder design” Florian Misoc, 2010 GoalsCostPortabilityConvenienceDurabilityScore Cost****0011 Portability1****113 Convenience10****12 Durability000****0

Measuring Achievement of Objectives VDI 2225: Verband Deutscher Ingenieure / Association of German Engineers No Mathematical foundation for scaling or normalizing the PCC ranking PCC ranking = subjective preferences Never weigh objectives: it could amplify the error (no mathematical foundation) Florian Misoc, 2010

Scale of Awarding Points Florian Misoc, 2010 Use-Value-AnalysisVDI-2225 Solution ValuePointsPerceived ValuePoints Absolutely useless Very inadequate 0101 Unsatisfactory0 Weak Tolerable 2323 Just tolerable1 Adequate Satisfactory 4545 Adequate2 Good w. drawbacks Good Very good Exceeds requirements Excellent Very good / Ideal4

Metrics for Objectives Metric = repeatable: conducting the test/experiment (under identical conditions & restrains) would lead to identical results/outcomes Metric outcomes: understandable units of measure Metric assessment: unambiguous interpretation Florian Misoc, 2010

Setting Priorities “Lack of planning from your part does not translate in a priority from my part…” Priority level: determined in the same fashion as awarding points Priority # 1: SAFETY!!! (read the “oath of the engineer”) Florian Misoc, 2010

Constrains: Limitations and Delimitations Limitations: are imposed by the available equipment, environmental conditions, time constrains, etc., and are out of experimenter’s control Delimitations: are imposed by the experimenter, as to restrict the purpose of said research Florian Misoc, 2010

Case Study and Examples Read and summarize: 1.Example 3.4.2: Establishing metrics for the beverage container 2.Example 3.6.1: Objectives and Constrains for the “Danbury Arm Support” 3.Example 3.6.2: Metrics for the Objectives “Danbury Arm Support” Due: same time as assignment of Chapter 3 Florian Misoc, 2010

Assignment: Exercise # 3.1, page 77 Exercise # 3.2, page 77 & 78 Exercise # 3.5, page 78 Exercise 3.6, page 78: as it applies to your particular group project Florian Misoc, 2010