Z556 Systems Analysis & Design Session 5 ILS Z556 1

Announcement Final specification document due date has changed: Not 5/1/2015, but 4/29/2015 ILS Z556 2

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 ILS Z556 3

Our Tool—Graphical Languages Advantages of a graphical language: a picture is worth a 1000 words ILS Z556 4

Too Big to See Models Too Small to See reveals relationship to the whole supports systemic thought creates a coherent design response ILS Z556 5

Work Models Graphical languages to capture knowledge about work Visual analysis, Complexity simplified, Focused understanding Make concepts concrete for team discussion “on the same page” Help communicate with clients Identification of breakdowns ILS Z556 6

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 ILS Z556 7

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 ILS Z556 8

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 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 ILS Z556 9

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 ILS Z556 10

Flow Model (B&H, p. 92) ILS Z U1 (Secretary) Worker Vendor Marketing manager - Produce proposal checks invoices Request to schedule meeting w/ president Bulletin board announcement Requires lots of 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 ILS Z556 12

Sequence Model (see B&H p ) 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 ILS Z556 13

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) ILS Z556 14

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 ILS Z556 15

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 ILS Z556 16

Sequence Model: Example ILS Z Intent: Hiring someone Trigger: someone quits Review her job Define candidates’ qualifications & job description Intent: 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 ILS Z 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 ILS Z 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 for collaboration) (free for 5 diagrams) ($5/month) (free plan included) (open source) ILS Z556 20

Decision Table ILS Z556 21

Specifying Processes Structured English is based on the logical constructs of: sequence selection iteration ILS Z556 22

Limited Entry Decision Table When a customer wants to purchase an item, different conditions determine the actions you should take. ILS Z556 23

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 ILS Z556 24

Limited Entry Decision Table Under $50YYNN Pays by check w/ 2 forms of ID YNYN Uses credit cardNYNY Ring up saleXX Call supervisor for approvalX Require a signature that matches one on the back of the card X ILS Z conditions actions

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 ILS Z N 3

Mixed Entry Decision Table Regular customer? YYYNNN Order value $ > > 100 Free shippingXX Discount given 010 % 15%05%10 % 27 conditions actions

Decision Tree: Hiring an Info Architect ILS Z College degree Formal education in IA Practical exp in IA Action Job Applicant yes no yes no yes no Job offer Keep app yes no Keep app Reject yes no yes no yes no Keep app 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 ILS Z556 29

Exercise: Flow Model Form 4 groups (5 people each) Develop a flow model based on the case presented in Alter’s article ILS Z556 30

Modeling What constitutes a good model? ILS Z556 31