Lesson 2 Flashcards#
Click a question to reveal the answer.
1. What is the Engineering Method?
A set of seven steps that can be used to effectively build something to accomplish a particular task. The steps start with adequately defining the project and continue through actual construction and evaluation of the design.
2. What are the seven steps of the Engineering Method, in order?
(1) Define the Problem, (2) Collect Data, (3) Create Viable Solutions, (4) Analyze Solutions and Select the Best Solution, (5) Construct Solution, (6) Test and Evaluate, (7) Reflection. The design projects in ECE 315 use steps 1-4 and 7.
3. What does it mean to define the problem (step 1)?
Explicitly stating the assumptions, requirements, and measures of merit. Do not just repeat the wording of the problem.
4. What is a viable solution?
A solution that meets all requirements. If an option is deemed inviable, the rationale for that decision must be clearly explained.
5. Why is the Test and Evaluate step needed?
After the system is constructed, we need to ensure it does what it is supposed to do. It is critical to document the results of any tests and evaluations.
6. What are the four steps of the systematic approach to problem solving?
Understand, Identify, Plan, and Solve.
7. What three categories of key information are listed in the Identify step?
Knowns (information given in the problem description), Unknowns (what we are being asked to find), and Assumptions (information that is not given but is required to solve the problem).
8. What is a decision matrix, and what is a measure of merit?
A decision matrix is a table that lets us systematically work through the metrics of each option to arrive at a single quantified score for each option. The metrics used in the decision are called measures of merit; each one should have a quantifiable value for every option under consideration.
9. What is normalization, and what are the two normalization equations?
Normalization converts the raw values of a measure of merit into unit-less scores between 0 and 1.
Minimize (smaller is better, such as cost):
\[Score_{norm} = \frac{Best\ Raw\ Value}{Raw\ Value}\]
Maximize (larger is better, such as fuel economy):
\[Score_{norm} = \frac{Raw\ Value}{Best\ Raw\ Value}\]
The option with the best raw value gets a normalized score of 1.
10. How can you tell that a normalized score was calculated with the wrong equation?
A normalized score must always be ≤ 1. If you get a score greater than one, you used the wrong equation (minimize vs. maximize).
11. What rule must the weights in a decision matrix follow, and how is a weighted score calculated?
Weights are assigned to each measure of merit based on relative importance, and they must total 100%, or 1.0. Because assigning weights is subjective, the chosen weights must be clearly stated and justified.
\[Score_{weighted} = Score_{norm} \times Weight\]
12. How is an option's total score found, and which option is the best?
Sum the weighted scores for that option:
\[Score_{total} = Score_{weighted_1} + Score_{weighted_2} + \ldots + Score_{weighted_N}\]
The option with the highest final score is the best option.
13. What are the two main differences between engineering notation and scientific notation?
First, the exponent must always be a multiple of 3. Second, the exponential term is replaced with a single-letter prefix. In this class the coefficient must range from 1 to 999.999 for final answers. Example: 825,300,000,000 W = 825.3 × $10^{9}$ W = 825.3 GW.
14. What are the engineering notation prefixes used in ECE 315?
tera (T) = $10^{12}$, giga (G) = $10^{9}$, mega (M) = $10^{6}$, kilo (k) = $10^{3}$, milli (m) = $10^{-3}$, micro (µ) = $10^{-6}$, nano (n) = $10^{-9}$, pico (p) = $10^{-12}$, femto (f) = $10^{-15}$, atto (a) = $10^{-18}$.
15. How do you write 0.0001975 s in engineering notation?
Add commas (0.000,197,5 s) and replace the second comma with the decimal point. The decimal point shifts 6 places to the right, so the exponent is -6: 197.5 × $10^{-6}$ s = 197.5 µs.