Z556 Systems Analysis & DesignSession 5

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Announcement• Final specification document due date has changed:

• Not 5/1/2015, but 4/29/2015

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Using Language to Focus Thought (cf., Wood, 1997)• The language gives you a way to see:

• a framework for interpreting the things you observe and• a structure of understanding you can elaborate as you learn

more

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Our Tool—Graphical Languages

• Advantages of a graphical language:• a picture is worth a 1000 words

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Too Big to See Models

Too Small to See

reveals relationship to the wholesupports systemic thought

creates a coherent design response

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Work Models

• Graphical languages to capture knowledge about workVisual analysis , Complexity simplified, Focused understanding

• Make concepts concrete for team discussion“on the same page”

• Help communicate with clients Identification of breakdowns

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5 Work Models in Contextual Design

• Flow model• The communication and coordination

• Sequence model• The detailed work steps to achieve a goal

• Artifact model• Physical things to support the work

• Culture model• Constraints on the work caused by policy, culture, or

values• Physical model

• Physical structure of the work environment

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Flow Model (Beyer & Holtzblatt, 1998, p. 92, 93)

• Represents the communication coordination necessary to make work happen

• The work must be broken into discrete parts• How departments really coordinate work IL

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People and organization

are bubbles on the model, and are

annotated with their position &

responsibilities

Flow Model Rules (Beyer & Holtzblatt, 1998, p. 91)

Flow is indicated as arrows between bubbles

People and organization

are bubbles on the model, and are

annotated with their position &

responsibilities

Artifacts are shown in boxes on the line

Informal

comm

unication and

actions are written

without a box

Places appear as large boxes, annotated with their responsibilities

Automated systems and databases usually should not go on the flow (they are shown as a large box with responsibilities only when they act like a physical place or an automated person)

Communication breakdowns are shown with a lightning bolt

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Flow Model Rules (Beyer & Holtzblatt, 1998, p. 91)

People and organization are bubbles on the model, annotated with their position & responsibilities

Flow is indicated as arrows between bubbles

Artifacts are shown in boxes on the line

Informal communication and actions are written without a box

Places appear as large boxes, annotated with their responsibilities

Automated systems and databases usually should not go on the flow (they are shown as a large box with responsibilities only when they act like a physical place or an automated person)

Communication breakdowns are shown with a lightning bolt

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Flow Model (B&H, p. 92)

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U1(Secretary)

Worker

VendorMarketing manager- Produce proposal

checks

invoices

Request toschedule meetingw/ president

Bulletin board

announcement

Requires lotsof iterations

- Ensure bills paid on time

President

checks to sign

- Run the business -Meet w/ management

Request for clarification

Proposal to proof

- Invoice for services

Specifying Processes

• Structured English• is based on the logical constructs of:

• sequence• selection• iteration

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Sequence Model (see B&H p.96-

101)

• Supplies the low-level, step-by-step information on how work is actually done

• Starts with the intent and trigger for the sequence and then lists each step in order

• Four components:• the steps by which work is done• the triggers that start a set of steps• The intents that are being accomplished• The breakdowns that prohibit workers from being

efficient

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Sequence Model

Sequence Model – Steps

• An action or the thought preceding an action

• Details of the tasks depend on the scope of the group (e.g., writing a memo)

• Interview Tip: Get more details rather than less

Sequence Model - Trigger

What causes the sequence of actions(May be discrete event, based on time, or less tangible)

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Collecting Sequences During an Interview• Triggers (that cause the sequence of actions):

• may be discrete events, e.g.,???• may be based on time, e.g.,???• may be less tangible, e.g.,???

• The system needs a way to tell the user there’s something to be done IL

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Sequence Model

Sequence Model - Intent • Every sequence has a

primary intent, which applies to the whole sequence

• Secondary intent applies to individual or groups of steps

Sequence Model - Breakdown

Where are the problems in the sequence

• Interview Tip: Hesitations & Errors often show breakdowns.

• Interview Tip: Ask how the system could do better.

• Interview Tip: Hesitations while thinking reveal decision points in the process

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Sequence Model: Example

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Intent: Hiring someone

Trigger: someone quits

Review her job

Define candidates’ qualifications & job descriptionIntent:Review the current position

Advertise the job opening

Receive applications

Review applicants

Check references of selected candidates

Intent: Eliminate unqualified candidates

Fewer candidates to invite on site

Sequence Model: Example

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Set up interview dates with selected candidates

Choose the best candidate

Making a job offer

Negotiate

Candidate accepts the job Candidate denies the offer

Choose the 2nd best candidate

Intent: make decisions about which candidate

UML: Activity Diagrams— Example

http://www.uml-forum.com/tools.htm

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• Charts activity as it moves between different people/groups

• Liner like the sequence model, but articulates different players like flow model

Tools for Creating Diagrams• https://www.lucidchart.com/(good for collaboration)• http://www.gliffy.com/ (free for 5 diagrams)• http://www.diagram.ly/ • http://creately.com/ ($5/month)• https://cacoo.com/ (free plan included) • http://dia-installer.de/ (open source)• https://www.draw.io/

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Decision Table

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Specifying Processes

• Structured English• is based on the logical constructs of:

• sequence• selection• iteration

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Limited Entry Decision Table• When a customer wants to purchase an item, different

conditions determine the actions you should take.

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Limited Entry Decision Table

• First, identify the conditions:• Under $50?• Pays by check w/ 2 forms of ID?• Uses credit card?

• Next, identify the actions• Ring up sale• Call supervisor for approval• Require a signature that matches one on the back of the card

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Limited Entry Decision TableUnder $50 Y Y N N

Pays by check w/ 2 forms of ID

Y N Y N

Uses credit card N Y N Y

Ring up sale X X

Call supervisor for approval X

Require a signature that matches one on the back of the card

X

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conditionsactions

General Rule• Check the number of rules

• The number of answer: M (e.g., 2 for Y/N)• The number of condition: N

• M = M x M x M x M . . . (M to the nth power)• E.g., 2 = 2 x 2 x 2 = 8rules IL

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N

3

Mixed Entry Decision Table

Regular customer?

Y Y Y N N N

Order value $ 0-49

50-99

> 100

0-49

50-99

> 100

Free shipping X X

Discount given

0 10%

15% 0 5% 10% 27

conditionsactions

Decision Tree: Hiring an Info Architect

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Collegedegree

Formal education in IA

Practicalexp in IA

Action

JobApplicant

yes

no

yes

no

yes

no

Job offer

Keep app

yes

no

Keep app

Reject

yes

no

yes

noyes

no

Keep app

Reject Reject

Reject

Exercise: Decision Tree/Table

• This is your last semester at ILS, and you are ready to look for jobs. You need to go through job postings and decide which jobs to apply for. Draw a decision tree or table with:• three conditions• three actions

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Exercise: Flow Model

• Form 4 groups (5 people each)• Develop a flow model based on the case

presented in Alter’s article

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Modeling

• What constitutes a good model?

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