RE: Exam 2 Review

Time Modalities of Requirements (3 types)

Time Modalities of Requirements (3 types)

“Shall” ~ legal binding

“should, may” ~ optional

“Will” ~ 3rd party COTS/MOTS/GOTS, not in current, but possibly in future

• COTS: commercial off the shelf system

• MOTS: military off the shelf system

• GOTS: Government off the shelf system

These modalities should only be used once

Is this equation true or false:

Problem = To-Be - As-is

False,

Problem + As-is = To-be is not true

Problem Analysis Roadmap

OMG: object management group

Starting point

• identify the problem

• find root causes

Understand the problem in the context of business goals

• problem cannot be used w/o a goal included

Consider alternatives and choose the best solutions to meet goals

Are requirements about problem or solution?

About the solution

3 Root Causes Techniques

1. Fishbone

2. Fault tree diagram

3. PIG: problem interdependent graph

Fishbone diagram

Problem = head of fishbone

Each rib-bone = possible cause of problem (root causes)

• Going to the 3rd level in rib-bone is considered more serious

Fault tree diagram

AND or OR symbols

Using this logic assumes completeness

In reality, logic doesn’t work

Anything mathematical is unreal, anything real is not mathematic

Clear relationships between siblings

However, no relationships with goals and alternatives

Which diagram is better? (3 Root cause diagrams)

Fishbone diagram

Mathematics most important thing

Numbers

• w/o numbers we cant have anything

What does number 1 mean?

The basis of mathematics

What if there are too many problems?

• Pareto principle

  • applicable basically everywhere

• engineering = Reality

• Science = theory

• resource limitation

Ontology

Essential (vocabulary) categories of:

• things (Ind. concepts)

• relationships btw things

• constraints on things

• constraints on relationships

3 different graphs

1. fishbone

2. PIG → (soft) problem independence graph

3. fault tree diagram

Ontology 3 levels

1. meta-level

2. class-level

3. toke/ground level

Ethnomethodology

Why is it difficult?

A wicked problem

Ethnomethodology

“say-do” problem

people know how to do things they normally don’t describe (tactic knowledge); descriptions of such things may be highly inaccurate

Ethnomethodology

Learning through observation

Some communication, mostly observation

Ethnomethodology

So what should be done, give 3 examples

1. London stack exchange

   1. 2yrs

   2. 10M

   3. Test engineers found no problems, so what’s wrong?

      1. Requirements engineers descriptions were highly inaccurate

2. Driving: lane/change intersection

   1. coming to red light

   2. determine pressure to apply to break per microsecond

   3. lane change

      1. check blind spots

3. Cooking

Usability Lab

important to create natural setting

big challenge for Ethnomethodology

It is used for

• Ethnomethodology

• testing in top companies

True or false: S achieves R to solve P in D?

False

What is the most important in a vision document?

Problem Statement/Definition

Vision Document Outline

Problem statement

4 rows:

• problem of

• affects

• impact

• successful solution

It is a system level document and it is communication between different wares (SW, HW, PW)

What is the problem with this problem statement in vision document example?

problem of: Keeping current on collegiate sports events

It is a goal statement, not a problem statement.

Problems should represent bad things, and cannot use a goal without a problem. Therefore it is invalid.

What does: “/” mean in diagrams

It relates to business

Diagram to use to show the flow of events. How to realize the use case?

Use a sequence diagram

Two different categories of diagrams?

1. software system

2. business

3 different diagrams (modeling)

1. class diagram

2. sequence diagram

3. class use case

What diagram to take text and make visual?

Sequence diagram

3 different version of UML

1. pre-uml

2. UML 1.x = offers ~9 diagrams

3. UML 2.y = offers ~12/13 diagrams

   1. UML 2.y has emphasis on soft. arch.

Most important word to describe software architecture?

Component.

Component diagrams are important.

Two famous groups of people in S.E.

Three Amigos: UML

Gang of four: Design patterns (GoF)

UML Diagrams

1. use case

2. activity

3. class

4. sequence

5. collaboration

6. state transitions

7. deployment

8. object

Given 1 use case, how many sequence diagrams can be used?

Infinitely many

Is UML diagram like a flowchart?

No

Can a class diagram be apart of a requirements document?

No

Do not include operation methods in objects e.g. chair

Relationships

Make sure to know what the arrows look like

UML 1.x

• 7 things

• 4 relationships

1. Association

2. generalization/specilization (example of this will be on test)

3. dependency

   1. weakest relationship in UML

4. realization

5. aggregation

6. composition

What is ontology of ERD?

Entities and relationships

What is the specification for UML?

UML is semi-formal specification

UML + OCL → fully formal

• OCL → object constraint language

2 new disciplines developed

Requirements engineering

Software architecture

• these 2 seen as critical to create large and complex systems

What is SADT?

structured analysis and design techniques

Operational concepts:

• personal, software, hardware functions

SADT 2 diagrams

actigrams: corresponds with IDEF0

SADT

Each diagram has 4 arrows

Input

Output

Control

Mechanism

Label of an Actigram

Must be a verb of verb phrase

Box annotation

• represents trace of stepwise refinement/decomposition

Information Contiguity Constraint

Multiple levels of SADT diagrams all have the same mechanism, output, control and input (they have to be preserved)

Example

What does A32 refer to?

A032, the second box in A3

What is IDEF0?

Stands for integration definition for function modeling

IDEF0 = SADT actigrams

IDEF1x = ERD + gen/spec

IDEF0 diagram syntax rules

Input/output:

• down and under

Control:

• up and over

Mechanisms:

• down and under

IDEF0

What are the 3 different contorls?

1. stakeholders

2. templates

3. tools

Is UML functional or non-functional?

Functional

what does security mean?

Confidentiality

Integrity

Availability

NFR Frameworks

What is a softgoal?

nonfunctional things

no optional solution

No clear cut definition

NFR Frameworks

What is a satisficing?

one softgoal can contribute positively, negatively, fully or partially towards other softgoals

satisfies ~ good enough

NFR Frameworks

What is a softgoal interdependence graphs (SIG)?

modeling non-functional requirements and interdependence btw them

Make (good enough): ++

help: +

hurt: -

break (bad enough): --

NFR frameworks

3 types of Refinement

1. NFR (thin line)

2. Operationalizing (thick line)

3. Claim (supporting | explaining) (broken line)

NFR frameworks

Contribution types

1. and (decomposition)

2. or (alternatives)

NFR frameworks

Labels (evaluation of softgoals/contributions)

1. satisficed

2. denied

3. conflicting

4. undetermined

Most important diagram (modeling)

Class diagram

Some notes

• Infinite # of illegal relationships

• finite # of legal relationships

• UML ability to decompose is important

  • decompose activities

  • divide and conquer

• Data says relationships are not applicable

• Box in SADT diagram should contain all info and nothing should be outside of it.

• SADT should have no diagonals. Only vertical and horizontal.