View
219
Download
0
Category
Tags:
Preview:
Citation preview
CHAPTER 3
Problem Solving and Systems
PROBLEM SOLVING
Humans have always been faced with problems to
solve.
They have always needed food, clothing, shelter and
healthcare.
These needs are met through technology.
People solve their problems using available
resources and knowledge.
HEADACHES
Have been a problem for a long time.
People used to drill hoes in a person’s skull!
This was supposed to let evil spirits escape. People
did not know enough about headaches to solve this
problem.
EARLY HUMANS…Solved problems of food
and shelter by using the
materials around them.
Caves were used as homes.
People gathered roots,
fruit, and seeds of plants to
eat, and made tools to hunt
animals for meat.
TODAY…
Problems are also those of human needs and
wants, but there are many more problems and they
are more complex than ever before. Some of these
problems involve society and the environment, such
as:• How can we dispose of wastes without harming the
environment?• How can we produce enough energy to meet our
increasing needs?• How can we assure a continuing supply of clean,
safe water?
GOOD DESIGN IN PROBLEM SOLVING
Solving a problem is rarely quick and easy.
We must understand exactly what is needed to solve the problem.
We must make our solution as low-cost and easy to use as
possible.
These solutions must be compared so that the best one is chosen.
Then, the best ideas are further refined and improved. Good
solutions to problems are those that work well, are
inexpensive, and cause little or no harm to the environment
and people.
EXAMPLES OF WELL DESIGNED TECHNOLOGICAL SOLUTIONS
Engineers, designers, and scientists solve a huge
number of different technological problems. These
can range from redesigning a stereo to creating new
life forms like a plant that repels insects. Here arte
some well-designed technological solutions:
THE TECHNOLOGICAL METHOD OF PROBLEM SOLVING
Problem solving is faster and easier, and results
are better, if people follow a procedure. The 7 steps
of problem solving are:• 1. Describe the problem as clearly & fully as
you can.• 2. Describe the results you want.• 3. Gather information• 4. Think of alternative solutions.• 5. Choose the best solution.• 6. Implement the solution you have chosen.• 7. Evaluate the solution and make necessary
changes.
STEP 1: DESCRIBE THE PROBLEM CLEARLY AND FULLY
To solve a problem, we must first understand it.
What has caused the problem? Here is an example of
a clearly stated problem:• People with arthritis in their fingers have a hard
time gripping small objects. They need an easy way to carry out such tasks as unlocking a door.
Once we know what a problem is, we can decide what to do about it.
RUBBER-BAND-POWERED VEHICLE
This may be a problem that might be presented in
class.
This vehicle must be able to carry a raw egg safely
over a distance of 50 feet on a smooth, level surface.
We want our vehicle to travel faster than other
competing vehicles.
In this case, the problem is to win a school
competition by constructing an egg carrying device.
To more clearly define the problem, however, we
must consider it very carefully.
RUBBER-BAND -POWERED VEHICLE CONT’D
We must recognize that winning the competition
means:• 1. We must design and construct a device powered
by rubber bands.• 2. The device must carry an egg without breaking it.• 3. The device must be faster than any other
student’s device.
STEP 2 : DESCRIBE THE RESULTS YOU WANT
We may have several goals in mind for the egg
transport problem. Perhaps we want:• To have fun• To improve our technical skills• To get a good grade• To impress our friends• Major goal to build a device that will win the
competition
DESIGN CRITERIA
Our goals should take into account any special
requirements imposed by the problem. The list of
specification must include all the requirements
of the problem. These requirements are called
design criteria.
If we were building a house, our design criteria
would include the kinds of rooms, number for
stories, and whether the house will have a basement
or an attic.
DESIGN CRITERIA FOR EGG TRANSPORT PROBLEM
1. The vehicle must carry a medium-size raw egg
without breaking it.
2. The vehicle must be painted attractively.
3. The vehicle must have an identification number.
4. The vehicle must travel faster than any other
competing vehicle.
Can you think of the other design criteria that was
mentioned?
LIMITATIONS
Problems generally have limitations.
The specifications should include these limitations.• 1. The vehicle must cost no more than two dollars.• 2. The vehicle must weigh no more than 1 pound.• 3. The vehicle must be able to fit into a 12” x 6” x 4”
container.• 4. The vehicle must be powered by no more than
four #6 rubber bands.
STEP 3: GATHER INFORMATION
This information gathering is called research.
Some companies and government agencies constantly perform
basic research into the nature of different materials and
processes. They don’t expect to produce any products immediately
from what they learn, but they save the results and hope that the
new knowledge will be useful at a later time.
Companies often do market research to determine if customers
will like a new product. Companies may ask potential buyers to fill
out a questionnaire to find out what they like or don’t like.
STEP 4 : THINK OF ALTERNATIVE SOLUTIONS
There is almost always more than one solution
to every problem.
We can suggest several ideas., each one of
which might do the job. These different ideas
for solutions are called alternatives.
One way to develop alternative solutions is to use
our past experience.
BRAINSTORMING
Another way of coming up with ideas.
During brainstorming, each person in a group can
suggest ideas.
One person writes all the ideas down; no one is
allowed to laugh at or criticize any idea, no matter
how foolish or unusual it might seem.
TRIAL AND ERROR
Another way to develop alternatives.
This is the way most people do jigsaw puzzles.
INSIGHT
A fourth way to develop alternatives.
Have you ever had an idea just pop into your head?
These sudden ideas are usually followed by the
“Aha!” response.
Insight comes from being thorough in researching
the problem, and from being creative in thinking
about the problem from many different angles.
ACCIDENT
Still, another way to come up with solutions is by
accident!
Some of the most important discoveries, like
penicillin, occur when the inventor goes as far as
possible and still doesn’t solve the problem.
A chance happening then provides the answer.
STEP 5 : CHOOSE THE BEST SOLUTION
Once you have developed your list of possible
alternatives, you need to select the best one.
Each alternative must be examined to see if it
meets the design criteria and constraints that were
defined in Step 2. Usually you can throw away the
alternatives that don’t meet the criteria or
constraints.
You may need to do further research on each
alternative.
OPTIMIZATION P. 56
Sometimes, the testing will suggest that if we
change on alternative slightly or combine two or
more alternatives, we will wind up with a better
solution.
The process of changing or combining
alternatives to improve them is called
optimization.
By optimizing the alternatives, we can get the best
possible solution to the problem.
STEP 6 : IMPLEMENT THE SOLUTION
Once we choose the best solution, we can begin to put it in place.
We are ready to try the solution under actual conditions.
Implementation means actually building or creating the
proposed solution.
Most often a prototype or model of the solution is made.
This is particularly important if the proposed solution is very large
and costly, or if many of the final products must be made, or if the
proposed solution presents risks to people or the environment.
STEP 7: EVALUATE THE SOLUTION AND MAKE NECESSARY CHANGES
We must study the solution and test is to see how
well if satisfies the requirements described in step
two.
Observing (monitoring) the results of the test may
suggest how we can improve the design or
construction of the solution.
The feeedback we get allows us to compare our
actual results with the desired results.
SOLVING REAL-WORLD PROBLEMS
Social and Environmental Concerns
Politics
Risk/Benefit Trade-Offs
Need for Continued Monitoring
Values
SYSTEMS
A system is a means of getting a desired result.
A technological system does this through technology.
For example, an automobile is a technological system for
traveling from one place to another.
A radio lets us listen to music or news.
A computer lets us do calculations quickly.
A system can be huge, such as a space shuttle. Or it can be
small, like a pocket calculator.
TECHNOLOGICAL SYSTEMS ARE ALL ALIKE IN ONE WAY…
Each has:• Inputs• A process• Outputs
THE BASIC SYSTEM MODEL
All systems include inputs, a process, and outputs.
Feedback is added to provide a better way of
controlling the system.
The basic system model can be used to
describe any technological system.
A system diagram can be drawn to show how these
parts work together in a system…..
INPUTS
The input is the command we give a system.
It is also the desired result.
When we turn on a t.v., we are giving it a
command. That command is: “Give us picture and
sound.”
THE PROCESS
The process is the action part of a system. It
combines the resources and produces results.
In an automobile, the process involves both the car
and the driver. The seven technological resources
are used in the process. Energy is stored in the
gasoline. The machine is the car. People (the driver),
information, time, materials, and capital work
together to make the car go 30 miles an hour.
OUTPUTS
The output is what is produced. It’s the actual
result.
We hope that the output matches the command
input.
That is, we hope that the car will go 30 miles an
hour when we step on the gas.
Most systems have more than one output.
FEEDBACK
How does the driver know when the car is going 30 miles
an hour?
The driver checks the speedometer. The speedometer
gives the driver feedback.
Feedback is information about the output that can be
used to change it.
When the car’s speed reaches 30 miles an hour, the
driver lets up on the gas.
MONITOR
The speedometer is a monitor.
A monitor gives feedback about output. It lets
us compare the actual result to the result we
want.
We can control the system, if needed, to get the
output we want.
Systems with feedback are sometimes called
control systems or feedback control systems.
CONTROL SYSTEM
A control system is being used to help you learn.
Your teacher uses homework and tests as monitors
to see how well you are learning.
Your teacher grades and returns assignments
both of you use this feedback to find out where you
are doing well and where you need more work or
perhaps some help.
LOOP SYSTEMS
Systems that have feedback are called closed-loop
systems. Feedback “closes” the loop from input to output.
Some systems don’t use feedback – these are called open-
loop systems. A person who wears a blindfold while trying to
draw a picture of a dog is an example of an open-loop system.
Without feedback, the person cannot compare the output to the
input. When the blindfold is removed, the person can draw the
picture more accurately. Now we have a closed-loop system.
MULTIPLE OUTPUTS
A system may produce several outputs. They
can be 4 types: desirable, undesirable, expected,
or unexpected.
SUBSYSTEMS
Systems are often made up of many smaller
systems called subsystems.
When you are trying to understand a large system,
you might find it helpful to break it into subsystems.
You can study each of them separately.
Suppose you want to look at a transportation
system that carries goods by truck from L.A. to New
York City.
You could break down the large system into smaller
ones.
Some of the subsystems would be the vehicle
system, the management system, and the
communication system.
Each of these could be broken down further into
more subsystems. You would want to create a
subsystem tree.
See figure on page 70.
IN YOUR NOTEBOOK, ANSWER THE FOLLOWING ITEMS
1. What are the 7 problem-solving steps listed in
this PowerPoint?
2. Give an example of how a person’s values might
affect his or her decision about the kind of car to
buy.
3. Name some subsystems that make up a large
railroad system.
Recommended