SE 4351 Requirements Engineering (INTRO)

What are the 3 kinds of wares?

• Hardware

• Software

• Peopleware

What is Peopleware?

• OF The People - Owner

• BY The People - Developer

• FOR The People - Customer/Client

Error Propagation in Lifecycle

What factors contribute to Project Success?

• Completed on time and on budget (28%)

• Canceled before completion (23%)

• Overran original estimates (49%)

The Chaos Ten Project Failures

1. Lack of User input/involvement

2. Incomplete/changing requirements & specifications

3. Unrealistic Expectations

4. Unclear Objectives

5. Didn’t need it any longer

6. Technology illiteracy

The Chaos Ten Project Success

1. User Involvement

2. Clear Business Objectives

3. Minimized Scope

4. Firm Basic Requirements

5. Formal Methodology

6. Reliable Estimates

How costly are Requirement Errors?

• COST = 100 x COST

COST(correcting design/implementation errors) = 100 X COST (correcting requirement errors)

What are three most frequent problems plaguing large software systems?

• Communication & Coordination

• Thin spread of domain application knowledge

• Changing & Conflicting requirements

Defining the problem is The Problem

What three key metrics can pinpoint a project’s success potential? (The Standish Group)

1. Project Size

2. Team Size

3. Project Duration

In requirements management: Smaller Projects have….

• smaller teams.

• fewer requirements.

• fewer communication issues.

• easier to manage.

• usually target more focused business objectives.

What will be the Key?

Changing Requirements

What is RE?

Requirements Engineering is the branch of System Engineering concerned with real world goals to provide services and constraints on software system.

What is Role of Requirements?

Agreement regarding the requirements between the system developers, customers, & end-users.

• Should be written in user language

• basis for software design

• support for verification/validation

• support for system evolution

What is essential?

• Modeling

  • “A model is a pattern, plan, representation, or description designed to show the main object or workings of an object, system, or concept”

• Systematic Decision Makings

  • “Decision making can be regarded as an outcome of mental processes (cognitive process) leading to the selection of a course of action among several alternatives. Every decision making process produces a final choice. The output can be an action or an opinion of choice

Software Architecture is called?

high-level/preliminary design

Component is called?

low-level/detailed design

What describes how components connect to each other?

software architecture specification

What Is Murphys Law?

Anything that can go wrong will go wrong

Is requirements engineering about the problem or the solution?

It is about Both

What are 3 types of defects?

• Program

• Design

• Specification

80% of defects come from what Phase?

Requirements Phase

What error does RE focus on?

Erroneous Spec