need analysis / problem statement by: prof: wilmer arellano fall 2008

Need Analysis / Problem Statement By: Prof: Wilmer Arellano

Fall 2008

Overview Prescribing the Design Process Problem Definition Need Analysis

The Designer-Client-User Triangle The Client’s Need

The Client Interview The User Needs

The Survey Need Analysis Example Problem Statement Assumptions and limitations. Operating environment.

Intended user(s Intended use(s).

References Excerpts from the book “Engineering Design,

a Project Based Introduction”, second edition by Clive I. Dym and Patrick Little. John Wiley and Sons, Inc. ISBN 0-471-25687-0

Karl T. Ulrich and Steven D.Eppinger. (2000). Product Design and Development. Second Edition. McGraw-Hill: New York

Prescribing the Design Process

Problem Definition

Input: client’s Need Statement

Tasks: Talk with the Client, (interview) Some Potential Users (Survey), Conduct your own Brainstorming Sessions, (Fishbone) Review Similar Products, Industry Reports, Literature,

Patents Talk to Marketing People, and Experts. Research, Market data publications, Market Trends.

Output: Revised Problem Statement Refined Objectives User Requirements Constraints Assumptions and Limitations

Need Analysis(The Client’s Need)

Client Statements usually have limitations because they often:

Contain errors, Show biases, or Imply solutions. “FIU College of Engineering needs to reconfigure

the intersection (Bias, the problem could be timing of the signals instead of reconfiguration) of Flagler Boulevard (Error) and 107th Avenue so students can cross the road.”

Need Analysis(The Client’s Need)

Customer: “We want a rear door installed on the aircraft we are ordering” (Implied Solution) Design, test, and get FHA (Functional Hazard

Assessment) approval for a new tail section with a door in order to make sale.

Need Analysis (The Designer-Client-User Triangle)

There are three parties involved in a design effort and we will use three different tools for each party to gather the information: The Client, who has objectives that the designer must clarify

We get information from the client by means of interviews The User, device, who has his own requirements

We get information from the users by means of Surveys or Focus Groups

The Designer, who must develop specifications such that something can be built to

satisfy everybody. The designers contribution comes from brainstorming.

Obtaining the Object Attributes and Lists of Objectives We will use a method based on attributes

to clarify the needs and obtain the problem statement and Project Objectives. Attribute: A quality or characteristic of

the object to be designed

Object Attributes Objectives or goals are ends that the design strives to achieve.

(We generally view design objectives They are normally expressed as “being” statements that say what the

design will be, as opposed to what the design must do.

Objectives are abstract Constraints are statements that expresses measurable bounds

for an element or function of the system. Constraints are typically stated as clearly defined limits whose

satisfaction can be framed into a binary choice, for example, the ladder material is a conductor or it is not.

The cost cannot exceed $95. Constraints values could be change to a different value

Object Attributes Functions are the things a design is supposed

to do, the actions that it must perform Functions are usually expressed as “doing”.

Lastly, implementations or means are ways of executing those functions that the design must perform .

Need analysis deals first with objectives and later with constraints

Object Attributes Examples Objectives

The Car should be lightweight The Car should be fast

Constraints are restrictions on a behavior or a value or some other aspect of a designed object’s performance The Car must not weight more than 1,000 pounds The Car must run at least 80 mph

Functions are the things a design is supposed to do, the actions that it must perform The Car will automatically control speed The Car will turn right and left

Lastly, implementations or means are ways of executing those functions that the design must perform . The power of the car is to be generated by a 4 cylinder gas engine

The Client’s Need The Product needs to be based on the

customer needs, make sure that you: Identify hidden needs as well as explicit needs. Keep record of the needs activity of the

development process. Ensure that no critical customer need is forgotten. All the team members understand the customer

needs.

The Client Interview Prepare a Structured interview wit questions like:

When and why do you use this type of product? Walk us through a typical session using the product. What do you like about the existing products? What do you dislike about the existing products? What issues do you consider when purchasing the product? What improvements would you make to the product? Are there already products on the market that have similar features? And you can always ask a second question:

What does that mean? Why do you want that?

Every Project is different please customize

Client Interview(Discovering the Roots)

5 Whys is a problem solving technique that allows you to get at the root cause of a problem fairly quickly. It was made popular as part of the Toyota Production System (1970’s.) By repeatedly asking the question "Why" (five is

a good rule), you can peel away the layers of symptoms that can lead to the root cause of a problem.

The User Needs(The Survey)

Characteristics End User Corporate

Socioeconomic Age Size – Volume

Gender Number of Employees

Income Number of Plants

Education Type of Organization

Marital Status Industry

Behavioral Brands Purchased Decision Makers

Coupon Redemption Growth Markets

Stores Shopped Public vs. Private

Loyalty Distribution Pattern

Hobbies

Reading Interests

Psychological Attitudes Management Attitudes

Personality Traits Management Awareness

Awareness Management Style

Recall

One team’s example

Not much technical information gathered in this Survey.

Price Question should be more accurate

15 Females and 15 Males

Majority of individuals 20 – 30 year old owners/renters

60 % Singles

77% Leave the home for more than One Day

A total of 5 have been burglarized un the past

50% wanted the alarm to sound between 5 – 10 seconds

Most of the people wanted the alarm close to a nearby door/window

Most of the people want to spend less than $50

They want in order of preference: Vibration Detector, Panic Button, Power Backup, Remote Control Access, Laser Beams and Motion Detector

One team’s example continued

Another Example. This team used good questions however it would have

been nice to see a table with the results

Electric motor preferred power plant

Five minute average flight time

Hard landing causing RC airplane inoperable for flight occurs within the

first five flights

Percentage of night flights negligible

Majority use NiCd nickel-cadmium batteries

Manual initiation of autonomous features

All channels including ailerons, throttle, elevator, and rudder need to be

supported

Slight desire for availability on seaplanes

Moderate ease of installation

Device has to be shock resistant

Device has to land on a flat surface

Autonomous feature has a manual override

Automatic recovery from unusual attitude

The Survey Survey results could depend on the facilitator

and how good that person explains the project and the intention of the survey.

To mitigate this problem write an introduction explaining the project and the purpose of the survey.

The Survey Group questions by categories

All uses related questions together All Price related questions together, etc.

Make all the questions multiple choice except for some ( 2 or 3) where you let the user give new ideas like:

Please indicate any uses not listed here that you would be interested in. Do not use Technical Terms or Trade Marks with no meaning to the user:

What would you use an ACME3 with DSP for? Marketing

Include some customer loyalty question inquiring about the customer purchase repetition if satisfied

Do you have any favorite brand? What makes a brand one of yours favorites?

Also break the price questions like: Would you pay $200 for a product like this? (Close to your estimate) Would you pay additional $150 if we offer additional bla, bla, bla?

Brainstorming(Discovering the Roots)

Finally your team will contribute to the project introducing new needs not presented neither by the client nor by the user. One way to help to unfold the roots of a problem is the Fishbone diagrams. You could use then during your brainstorming in this section of the proposal.

Fishbone Diagrams. Cause-effect diagrams are also called Ishikawa diagrams after their

creator, Dr. Kaoru Ishikawa. These diagrams are used in identifying and organizing the possible causes of a problem. They are sometimes referred to as fishbone diagrams because they resemble the skeleton of a fish, with a head, spine, and bones.

Brainstorming

Customer Needs Example:Cordless Screwdrivers

The Client’s Need Statement “I need a drill with protective shields around

the battery contacts that can withstand me and allows me to work no matter what with no surprises”

The questions in the client interview will clarify this statement. See results in the next slide.

Client’s Need Interpretation(Client Interview) The Client needs wireless screwdriver with the

following characteristics: The battery is protected from accidental shorting. The screwdriver operates normally after repeated

dropping. The screwdriver operates normally in the rain. The screwdriver provides an indication of the

energy level of the battery. In your proposal, use the main ideas in your need analysis but list the questions and answers in

one appendix

From the Survey The SD drives screws faster than by hand The SD can drive screws into hardwood SD makes it easy to start a screw The SD can be used on electrical devices The SD fits in a toolbox easily The SD is easy to set-up and use The SD is not Heavy The SD costs Less than $95 The SD has Tungsten Carbide bits The SD has Plastic Body The SD can be used outdoors The SD can be used indoors

Your Brainstorming • This information is generated by your team

Object Attributes We need to combine the attributes indicated

by the client with those coming from the survey and from your brainstorming into a table.

Conduct Interview Conduct Survey Conduct Brainstorming Put all results in a table Remove repeated entries Eliminate:

Functions Constraints Implementations

Source AttributeClient The battery is protected from accidental shortingClient The screwdriver operates normally after repeated dropping.Client The SD operates normally in the rainClient The SD provides an indication of the energy level of the batterySurvey The SD drives screws faster than by handSurvey The SD can drive screws into hardwoodSurvey The SD makes it easy to start a screwSurvey The SD can be used on electrical devicesSurvey The SD fits in a toolbox easilySurvey The SD is easy to set-up and useSurvey The SD is not HeavySurvey The SD costs Less than $95Survey The SD has Tungsten Carbide bitsSurvey The SD has Plastic BodySurvey The SD can be used outdoorsSurvey The SD can be used indoorsTeam The Sd Prevents FatigueTeam The SD feels good in the user's handTeam The SD is comfortable when the user pushes on itTeam The SD is comfortable when the user resists twistingTeam The SD weight is just rightTeam The SD is balanced in the user's handTeam The SD resists corrosion when left outside or in damp placesTeam The SD maintains power for several hours of heavy useTeam The SD can be dropped from a ladder without damageTeam The SD lasts a long timeTeam The SD prevents inadvertent switching offTeam The SD is safeTeam Must meet OSHA requirements (Occupational Safety and Health Administration)Team The SD is easy to use.Team The SD is easy to turn onTeam The SD can be used while rechargingTeam The SD retains the screw before it is drivenTeam The SD is easy to storeTeam The SD is easy to rechargeTeam The SD drives sheet metal screws into metal ductwork

• List all The attributes from:– Client Interview

– Survey

– Brainstorming

Source AttributeClient The battery is protected from accidental shortingClient The screwdriver operates normally after repeated dropping.Client The SD operates normally in the rainClient The SD provides an indication of the energy level of the batterySurvey The SD drives screws faster than by handSurvey The SD can drive screws into hardwoodSurvey The SD makes it easy to start a screwSurvey The SD can be used on electrical devicesSurvey The SD fits in a toolbox easilySurvey The SD is easy to set-up and useSurvey The SD is not HeavySurvey The SD costs Less than $95Survey The SD has Tungsten Carbide bitsSurvey The SD has Plastic BodySurvey The SD can be used outdoorsSurvey The SD can be used indoorsTeam The SD Prevents FatigueTeam The SD feels good in the user's handTeam The SD is comfortable when the user pushes on itTeam The SD is comfortable when the user resists twistingTeam The SD weight is just rightTeam The SD is balanced in the user's handTeam The SD resists corrosion when left outside or in damp placesTeam The SD maintains power for several hours of heavy useTeam The SD can be dropped from a ladder without damageTeam The SD lasts a long timeTeam The SD prevents inadvertent switching offTeam The SD is safeTeam Must meet OSHA requirements (Occupational Safety and Health Administration)Team The SD is easy to use.Team The SD is easy to turn onTeam The SD can be used while rechargingTeam The SD retains the screw before it is drivenTeam The SD is easy to storeTeam The SD is easy to rechargeTeam The SD drives sheet metal screws into metal ductwork

• Remove repeated entries

Object Attributes We need to eliminate from the table all those

attributes which are not objectives. From the eliminated attributes, only the

constraints will be incorporated back latter. The remaining table will be the list of

Objectives

AttributeThe battery is protected from accidental shortingThe SD operates normally in the rainThe SD provides an indication of the energy level of the batteryThe SD drives screws faster than by handThe SD can drive screws into hardwoodThe SD makes it easy to start a screwThe SD can be used on electrical devicesThe SD fits in a toolbox easily ContraintThe SD is easy to set-up and useThe SD is not HeavyThe SD costs Less than $95The SD has Tungsten Carbide bits ImplementationThe SD has Plastic Body ImplementationThe SD can be used outdoorsThe SD can be used indoorsThe SD Prevents FatigueThe SD feels good in the user's handThe SD is comfortable when the user pushes on itThe SD is comfortable when the user resists twistingThe SD weight is just rightThe SD is balanced in the user's handThe SD resists corrosion when left outside or in damp placesThe SD maintains power for several hours of heavy use ContraintThe SD can be dropped from a ladder without damage ContraintThe SD lasts a long timeThe SD prevents inadvertent switching offThe SD is safeMust meet OSHA requirements (Occupational Safety and Health Administration) ContraintThe SD is easy to use.The SD is easy to turn onThe SD can be used while rechargingThe SD retains the screw before it is drivenThe SD is easy to storeThe SD is easy to rechargeThe SD drives sheet metal screws into metal ductwork

Project AttributesEliminate Constraints,

Functions and Implementations

Pruned List of ObjectivesObjectives

The battery is protected from accidental shortingThe SD operates normally in the rainThe SD provides an indication of the energy level of the batteryThe SD drives screws faster than by handThe SD can drive screws into hardwoodThe SD makes it easy to start a screwThe SD can be used on electrical devicesThe SD is easy to set-up and useThe SD is not HeavyThe SD can be used outdoorsThe SD can be used indoorsThe SD Prevents FatigueThe SD feels good in the user's handThe SD is comfortable when the user pushes on itThe SD is comfortable when the user resists twistingThe SD weight is just rightThe SD is balanced in the user's handThe SD resists corrosion when left outside or in damp placesThe SD lasts a long timeThe SD prevents inadvertent switching offThe SD is safeThe SD is easy to use.The SD is easy to turn onThe SD can be used while rechargingThe SD retains the screw before it is drivenThe SD is easy to storeThe SD is easy to rechargeThe SD drives sheet metal screws into metal ductwork

Project Objectives Next we have to order the objectives by

similar categories. One way to start grouping entries on the list is

to ask ourselves why we want them. For example, why do we want battery to be

protected from accidental shorting. The answer is probably because that’s part of

what makes a screwdriver “safe”, which is another entry on our list.

Now we test “safe” against all the objectives and group together all of them related to “safe”.

Project Objectives

The SD is safeThe SD can be used on electrical devicesThe battery is protected from accidental shortingThe SD operates normally in the rain

Project Objectives Similarly, we could ask why we care whether

the screwdriver can be used indoors. In this case, the answer is not on the list we

want it to be used indoors because otherwise it would not be useful.

So we add Useful to the list of objectives and group together all the related objectives.

Project ObjectivesThe SD is UsefulThe SD can drive screws into hardwoodThe SD drives sheet metal screws into metal ductworkThe SD drives screws faster than by handThe SD can be used outdoorsThe SD can be used indoorsThe SD can be used while rechargingThe SD provides an indication of the energy level of the battery

Repeating the last Step we would find that “Easy to Use” and “Durable” must be included as objectives

Project Objectives

The SD is Easy to UseThe SD makes it easy to start a screwThe SD retains the screw before it is drivenThe SD is easy to set-up and useThe SD is easy to turn onThe SD prevents inadvertent switching offThe SD is easy to rechargeThe SD is easy to store

The SD is DurableThe SD lasts a long timeThe SD resists corrosion when left outside or in damp places

The SD is UsefulThe SD can drive screws into hardwoodThe SD drives sheet metal screws into metal ductworkThe SD drives screws faster than by handThe SD can be used outdoorsThe SD can be used indoorsThe SD can be used while rechargingThe SD provides an indication of the energy level of the battery

The SD is Easy to UseThe SD makes it easy to start a screwThe SD retains the screw before it is drivenThe SD is easy to set-up and useThe SD is easy to turn onThe SD prevents inadvertent switching offThe SD is easy to rechargeThe SD is easy to store

The SD is DurableThe SD lasts a long timeThe SD resists corrosion when left outside or in damp places

The SD Prevents FatigueThe SD feels good in the user's handThe SD is comfortable when the user pushes on itThe SD is comfortable when the user resists twistingThe SD is balanced in the user's handThe SD weight is just right

The SD is safeThe SD can be used on electrical devicesThe battery is protected from accidental shortingThe SD operates normally in the rain

The Result Is the Grouped Objectives List

Project Objectives If we repeat the process once more we would

find that “Marketable” should be included as an objective that encompass “Useful” and “Durable”

The next step would be to establish a hierarchy within each objective and do some style corrections. The final result is shown in the next page.

The Result Is the Indented Objectives List

1. Marketable 1.1. Useful

1.1.1. Useful for Wood Works 1.1.2. Useful for Metal Works 1.1.3. Faster than a Manual Screwdriver 1.1.4. Useful outdoors 1.1.5. Useful indoors 1.1.6. Can be used while recharging 1.1.7. The SD provides an indication of the energy level of the battery

1.2. Durable 1.2.1. Resists corrosion when left outside or in damp places

2. Easy to Use

2.1. Easy to set-up and use 2.2. Easy to turn on 2.3. Prevents inadvertent switching off 2.4. Makes it easy to start a screw 2.5. Retains the screw before it is driven 2.6. Easy to recharge 2.7. Easy to store

3. Prevents Fatigue

3.1. Feels good in the user's hand 3.2. Comfortable when the user pushes on it 3.3. Comfortable when the user resists twisting 3.4. Balanced in the user's hand

4. Safe

4.1. Can be used on electrical devices 4.2. Minimizes the probability of short circuits 4.3. The SD operates normally in the rain

Three Steps1. Ask why you care for an objective.

1. If there is a Parent objective use it to group all related objectives

2. If there is no Parent objective create it and group all related objectives

3. If there are related parent objectives then create a Grandparent objective

PrioritizingPairwise Comparison Charts

We show in the table above a pairwise comparison chart (PCC) for our four-objective screwdriver design. The entries in each box of the chart are determined as binary choices, that is, every entry is either a 1 or a 0. Along the row of any given goal, say Prevents Fatigue, we enter a zero in those columns for the goals Marketable and Safe that are preferred over Prevents Fatigue, and we enter 1 in the Easy to Use column because Prevents Fatigue is preferred over Easy to Use . We also enter zeroes in the diagonal boxes corresponding to weighting any goal against itself, and we enter ratings of 1/2 for goals that are equally valued.

Sometimes we get really lucky and our client expresses strong and clear preferences, or perhaps the potential users do, so that the designer doesn’t have to do an explicit ranking. More often, however, we do have to do some ranking or we have to place some values ourselves.

Marketable Easy to Use Prevents Fatigue Safe ScoreMarketable **** 1 1 0 2Easy to Use 0 **** 0 0 0Prevents Fatigue 0 1 **** 0 1Safe. 1 1 1 **** 3

Pairwise Comparison Chart PCC

The Result Is the Ordered Indented Objectives List

1. Safe. 1.1. Can be used on electrical devices 1.2. Minimizes the probability of short circuits 1.3. The SD operates normally in the rain

2. Marketable

2.1. Useful 2.1.1. Useful for Wood Works 2.1.2. Useful for Metal Works 2.1.3. Faster than a Manual Screwdriver 2.1.4. Useful outdoors 2.1.5. Useful indoors 2.1.6. Can be used while recharging 2.1.7. The SD provides an indication of the energy level of the battery


3. Prevents Fatigue 3.1. Feels good in the user's hand 3.2. Comfortable when the user pushes on it 3.3. Comfortable when the user resists twisting 3.4. Balanced in the user's hand

4. Easy to Use


Problem Statement The Problem Statement is a paragraph

summarizing the objectives and constraints that is later followed by the list of objectives and constraints.

The main goal of this project is to design and build a prototype of a safe screwdriver that will be useful for metal and wood works. The screwdriver will be good for indoor as well as outdoor jobs and will resist water and shocks. The unit must be safe, allow works on electrical equipment and pose a minimum risk of causing short circuits. Emphasis will be stressed on easiness of use, storage and durability. Users of the newly design screwdriver will feel a comfortable experience with minimum fatigue and will be able to work under the rain with no safety risks. The cost of the unit must not exceed $95 and it must be OSHA compliant.

Objectives. The following is the list of objectives for the Safe Screwdriver:

1. Safe. 1.1. Can be used on electrical devices 1.2. Minimizes the probability of short circuits 1.3. The SD operates normally in the rain

2. Marketable

2.1. Useful 2.1.1. Useful for Wood Works 2.1.2. Useful for Metal Works 2.1.3. Useful outdoors 2.1.4. Useful indoors 2.1.5. Can be used while recharging 2.1.6. Faster than a Manual Screwdriver 2.1.7. The SD provides an indication of the energy level of the

battery


3. Prevents Fatigue 3.1. Feels good in the user's hand 3.2. Comfortable when the user pushes on it 3.3. Comfortable when the user resists twisting 3.4. Balanced in the user's hand

4. Easy to Use


Constraints

Following the proposal outline, after the objectives you have to continue with the constraints. Make sure that you follow the correct numbering indicated in the posted proposal outline.Constraints

1. The SD fits in a toolbox easily 2. The SD can be dropped from a ladder without damage 3. The SD maintains power for several hours of heavy use 4. Must meet OSHA requirements (Occupational Safety and Health

Administration) 5. The SD costs Less than $95

Assumptions and Limitations Assumption – The result of any project decision, which is required to complete

the project definition, but is not a physical limit (minimum or maximum) that was imposed by the client, the technology used, or a physical law. Assumptions are the result of decisions that can be made by the team and affect the end-product design and implementation. Examples would include: The maximum number of simultaneous users of a computer program, or The maximum number of books to be stored on the shelves of a bookcase.

Limitation – The result of any project decision, which is required to complete the project definition, but is a physical limit (minimum or maximum) that was imposed by the technology used, or a physical law. Limitations are the result of things over which the team has no control, but must consider in its end-product design and implementation. Examples would include: The maximum weight or size of user that would fit in the product without damaging it. The maximum power consumption, or (Limited by size of PS or Breakers) The maximum speed of the end product (limited by the type of gates or

microcontroller)

Assumptions and Limitations We care about technical Assumptions and

Limitations. Please do not list in your assumptions things like: The user has technical background or The weather will be fairly good

Do not confuse constraints with limitations

Operating environment For any end product other than simply a calculation,

it is essential to know the environment to which the end product will be exposed or experience.

For example, will the end product be exposed to dusty conditions, extreme temperatures, or rain or other weather elements?

Is the end product likely to be dropped or thrown? This information is necessary in order to design an

end product that can withstand the hazards to which it is expected to be exposed. This element shall be at least one paragraph in length.

Intended user(s) and intended use(s).

Knowing the characteristics of the end users makes it much easier to design an end product that will be accepted and used.

The expected end uses are equally important. This description should include what uses are expected as well as what uses are not to be considered

Class Assignment For your Senior Design I Project

Perform The Need Analysis and formulate: Problem Statement Objectives Constraints Assumptions Limitations

You will be writing sections II, III, IV A. and VII of your report.

Prepare your Project Summary Make sure you keep the original numbering

Review Prescribing the Design Process Problem Definition Need Analysis

The Designer-Client-User Triangle The Client’s Need

The Client Interview The User Needs

The Survey Need Analysis Example Problem Statement Assumptions and limitations. Operating environment.

Intended user(s Intended use(s).

&&QuestionsQuestions

AnswersAnswers

need analysis / problem statement by: prof: wilmer arellano fall 2008

Documents

design objectives

design effort

product design

book engineering design

analysis problem statement

project objectives

user trianglethere

interviewsthe user