Project Dimensions, Software Development Lifecycle

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Software Project Management (CS615)

LECTURE # 3

1. Introduction & Fundamentals

1.8

Project Dimensions

⇒ Product and Technology

The 80:20, rule was originated by Vilfredo Pareto, an Italian economist who

studies the distribution of wealth in a variety of countries around 1900. He

discovered a common phenomenon: about 80% of the wealth in most countries

was controlled by a consistent minority -- about 20% of the people. Pareto called

this a "predictable imbalance." His observation eventually became known as

either the "80:20 rule" or "Pareto's Principle."

The credit for adapting Pareto's economic observations to business goes to the

"Father of Total Quality Management," service quality consultant Joseph M.

Juran. In 1950, he published "The Quality Control Handbook," which first

recognized the applicability of the Pareto principle in the context of inventory

management, e.g.:

20% of the repair parts normally account for 80 percent of the total

inventory

80% of production volume usually comes from 20% of the producers

He subsequently recognized that this rule of thumb was universally applicable

across fields of endeavor. As a credit to Pareto's work, Juran named his finding

the Pareto Principle. This universal management theory became generalized as

"the 80-20 Rule":

The "80:20 rule" has become one of the best known "leadership shorthand terms"

reflecting the notion that most of the results (of a life, of a program, of a financial

campaign) come from a minority of effort (or people, or input).

The Rule, states that a small number of causes (20%) is responsible for a large

percentage (80%) of the effect. It means that in anything a few (20 percent) are

vital and many (80 percent) are trivial.

There is an inherent imbalance between cause and effect, effort and reward, inputs

and outputs, etc; and that imbalance tends to the ratio of 80:20. So, if we know

which 20% of our work produces 80% of our income, we can do more of it and

our income will increase proportionately!

Software Project Management (CS615)

You know 20 percent of you stock takes up 80 percent of your warehouse space

and that 80 percent of your stock comes from 20 percent of your suppliers. Also

80 percent of your sales will come from 20 percent of your sales staff. 20 percent

of your staff will cause 80 percent of your problems, but another 20 percent of

your staff will provide 80 percent of your production. It works both ways.

Some Sample 80/20 Rule Applications

80% of process defects arise from 20% of the process issues.

20% of your sales force produces 80% of your company revenues.

80% of delays in schedule arise from 20% of the possible causes of the delays.

80% of customer complaints arise from 20% of your products or services.

How It Can Help You

The value of the Pareto Principle for a manager is that it reminds you to focus on

the 20 percent that matters. Of the things you do during your day, only 20 percent

really matter. Those 20 percent produce 80 percent of your results. Identify and

Characteristic

focus on those things. When the fire drills of the day begin to sap your time,

remind yourself of the 20 percent you need to focus on. If something in the

schedule has to slip, if something isn't going to get done, make sure it's not part of

that 20 percent.

Pareto's Principle, the 80/20 Rule, should serve as a daily reminder to focus 80

percent of your time and energy on the 20 percent of you work that is really

important. Don't just "work smart", work smart on the right things.

Size

The larger product, there will be more requirements and features to deliver,

eventually it will take more time in its production. So if you cut the size of the

produce to half it will save you 60% of the effort.

Characteristic

Development Tools

Software Project Management (CS615)

Customer delivered value

Value of products

Total value

Value of services

Personal value

Real value to

Image value

the customer

Financial cost

Total costs

Time cost

Energy cost

Psychical cost

1.9

Project Phases

Organizations performing projects will usually divide each project into several

Project phases to improve management control and provide for links to the

ongoing operations of the performing organization.

Collectively, the project phases are known as the project life cycle. Software

development, just like most other activities, has a beginning, middle and an end.

The end of one development activity is sometimes perceived as being linked to

the beginning of a new development activity thus producing a cycle of beginning-

middle-end, link, beginning-middle-end, link, and so forth.

This view of software development is referred to as the software development

life cycle.

A project has five phases. Here's a brief summary of each:

⇒ Initiation

Articulate your vision for the project, establish goals, assemble your team,

and define expectations and the scope of your project.

⇒ Planning

Refine the scope, identify specific tasks and activities to be completed,

and develop a schedule and budget.

⇒ Executing

Accomplish your goals by leading your team, solving problems, and

building your project.

Software Project Management (CS615)

⇒ Controlling

Monitor changes to the project make corrections, adjust your schedule to

respond to problems, or adjust your expectations and goals.

⇒ Closing

Deliver your project to your audience, acknowledge results, and assess its

success. Take the time to compose a written evaluation of the project and

the development effort.

The middle three phases are not sequential. You will find that you are constantly

planning, executing, and controlling your project as necessary.

Aren't these phases really just common sense? In many ways, yes, but keep in

mind that software development, whether a few Web pages or a complex CD-

ROM, is a complex, unpredictable process.

Most software projects (something like 80 percent) are delivered late,

substantially over budget, and incomplete. The more effort you put into managing

your project, the more you increase your chances of success.

 Characteristics of Project Phases

Each project phase is marked by completion of one or more deliverables. A

deliverable is a tangible, verifiable work product such as a feasibility study, a

detail design, or a working prototype. The deliverables, and hence the phases, are

part of a generally sequential logic designed to ensure proper definition of the

product of the project.

The conclusion of a project phase is generally marked by a review of both key

deliverables and project performance to date, to a) determine if the project should

continue into its next phase and b) detect and correct errors cost effectively. These

phase-end reviews are often called phase exits, stage gates, or kill points.

Each project phase normally includes a set of defined deliverables designed to

establish the desired level of management control. The majority of these items are

related to the primary phase deliverable, and the phases typically take their names

from these items: requirements, design, build, test, startup, turnover, and others,

as appropriate.

 Characteristics of the Project Life Cycle

The project life cycle serves to define the beginning and the end of a project. For

example, when an organization identifies an opportunity to which it would like to

respond, it will often authorize a needs assessment and/or a feasibility study to

decide if it should undertake a project. The project life-cycle definition will

determine whether the feasibility study is treated as the first project phase or as a

separate, standalone project.

Software Project Management (CS615)

The project life-cycle definition will also determine which transitional actions at

the beginning and the end of the project are included and which are not. In this

manner, the project life-cycle definition can be used to link the project to the

ongoing operations of the performing organization.

The phase sequence defined by most project life cycles generally involves some

form of technology transfer or handoff such as requirements to design,

construction to operations, or design to manufacturing. Deliverables from the

preceding phase are usually approved before work starts on the next phase.

However, a subsequent phase is sometimes begun prior to approval of the

previous phase deliverables when the risks involved are deemed acceptable. This

practice of overlapping phases is often called fast tracking.

Project life cycles generally define:

What technical work should be done in each phase (e.g., is the work of the

architect part of the definition phase or part of the execution phase?).

Who should be involved in each phase (e.g., implementers who need to be

involved with requirements and design).

Project life-cycle descriptions may be very general or very detailed. Highly

detailed descriptions may have numerous forms, charts, and checklists to

provide structure and consistency. Such detailed approaches are often called

project management methodologies.

Most project life-cycle

descriptions

number

common

characteristics:

Cost and staffing levels are low at the start, higher toward the end, and drop

rapidly as the project draws to a conclusion.

The probability of successfully completing the project is lowest, and hence

risk and uncertainty are highest, at the start of the project. The probability of

successful completion generally gets progressively higher as the project

continues.

The ability of the stakeholders to influence the final characteristics of the

project's product and the final cost of the project is highest at the start and

gets progressively lower as the project continues. A major contributor to this

phenomenon is that the cost of changes and error correction generally

increases as the project continues.

Care should be taken to distinguish the project life cycle from the product life

cycle. For example, a project undertaken to bring a new desktop computer to

market is but one phase or stage of the product life cycle.

Although many project life cycles have similar phase names with similar

deliverables required, few are identical. Most have four or five phases, but some

Software Project Management (CS615)

have nine or more. Even within a single application area, there can be significant

variations.

One organization's software development life cycle may have a single design

phase while another's has separate phases for functional and detail design.

Subprojects within projects may also have distinct project life cycles. For

example, an architectural firm hired to design a new office building is first

involved in the owner's definition phase when doing the design, and in the

owner's implementation phase when supporting the construction effort. The

architect's design project, however, will have its own series of phases from

conceptual development through definition and implementation to closure. The

architect may even treat designing the facility and supporting the construction as

separate projects with their own distinct phases.

 Project Life Cycle includes the following Phases and activities:

A. Concept Phase

1. User Need

2. Initial Investigation

3. User Review

4. System Performance Design

5. Candidate Review

6. Study Phase Report

B. Requirements Phase

1. The software requirements specification document

2. The project development plan

3. The software test plan

C. Design Phase

1. General System Review

2. Processing Requirements Identification

3. Data Base Design

4. Control Requirements

5. Output Design

6. Input Design

7. Software Selection

8. Equipment Selection/Acquisition

9. People

10. Reference Manual Identification

11. Plans

12. Design Specifications Preparation

13. Design Phase Report Preparation

D. Development Phase

Software Project Management (CS615)

1. Implementation Planning

2. Computer Program Design

3. User Review

4. Equipment Acquisition and Installation

5. Coding and Debugging

6. Computer Program Testing

7. System Testing

8. Reference Manual Preparation

9. Personnel Training

10. Changeover Plan Preparation

11. Development Phase Report Preparation

12. User Acceptance Review

E. Operation Phase

1. System Changeover

2. Routine Operation

3. System Performance Evaluation

4. System Changes/Enhancements

1.10

Software Development Lifecycle

⇒ Water Fall Theme

Software development, just like most other activities, has a beginning, middle and

an end. The end of one development activity is sometimes perceived as being

linked to the beginning of a new development activity thus producing a cycle of

beginning-middle-end, link, beginning-middle-end, link, and so forth. This view

of software development is referred to as the software development life cycle.

There are many variations of the software development life cycle. Figure 1

presents a simple life cycle that was common during the first few decades of

software development. In those early days of software development, the

programmer would create programs by iterating from code to fix then back to

code, and then to fix again, until something acceptable was (hopefully) produced.

At the start of the cycle, there was usually no clear concept of what was required,

and the basic development procedure was a form of 'let's see what we can do'

approach.

The software development method represented by the development cycle in Fig.1

is often referred to as the code and fix method (for obvious reasons). Software

development methodologies have come a long way since the days of code and fix,

though it is surprising how much software is still being developed this way.

Successful management of any project, especially software projects, requires

planning, and planning is impossible with code and fix, which is totally

unpredictable. Management of software development within an engineering

Software Project Management (CS615)

discipline is based on a much more orderly set of development phases. These

phases are not implemented solely by programmers; they require software

engineers. In fact, programming has become a relatively small part of the modern

software development cycle, as is evident from Table 1.

The numbers in Table 1 are derived from the general shift in emphasis to software

planning (requirements and design) and testing. Commercial data processing

systems, with some exceptions, still spend a significant amount of development

time in the programming and unit testing phase. Real-time systems are often more

complex, and may include extensive hardware software integration. This usually

requires more planning and more integration and testing.

Concept

Code

Fix

Maintain

Figure 1: the code and fix method

Table 1 Estimated percentage of time spent in each major software development phase

Planning

Code and unit test Integration and test

Commercial data processing 25%

40%

35%

Real-time systems

35%

25%

40%

Military systems

40%

20%

40%

Military systems require high reliability and are usually closely supervised by the

customer, leading to a significant increase in the time spent in planning.

The data in Table 1, of course, represents a generalization; commercial data

processing systems can be just as complex as a real-time system.

Figure 2 presents the basic phased model of a software development cycle. This

model, called the Waterfall model, gets its name from the way in which each

phase cascades into the next (due to overlapping), as demonstrated in Fig. 3.

Some interpretations of the Waterfall model, like the one that follows, combine

the top level design and the detailed design phases into a single design phase, and

the integration and test phases into a single phase. In fact, there are many

variations of the classic Waterfall model, but they are all based upon a systematic

transition from one development phase to the next, until the project is complete.

Software Project Management (CS615)

Conception

Maintenance

Software

Requirements

Test

Top level

Design

Integration

Detailed

Design

Implementation

Figure 2: The phased model of the software development life cycle

Conception

Software requirements

Top level" design

Detailed design

Implementation

Integration

Test

Maintenance

Figure 3: The Waterfall model of the software development life cycle

⇒ Rapid prototyping There are other development methodologies that do not move

from one phase to the next like the Waterfall model. Rapid prototyping, for

Software Project Management (CS615)

instance, iterates in a mini-development phase until a system prototype is

developed (see Fig. 4). After the prototype is complete, the Waterfall approach

can then be implemented to complete the full system. Rapid prototyping is

particularly helpful in projects where the requirements are difficult to specify. The

prototype can be used as a tool for analyzing and determining what the

requirements should be.

⇒ The Spiral model, described by Boehm (1988), is another development method

that iterates between the requirements, design and implementation phases.

However, the Spiral model continues iterating until the final system is complete.

Within each, iteration, the Spiral model follows a phased approach similar to the

Waterfall model.

Different models maybe suitable for different software projects or for different

software development organizations However, a good model must include certain

fundamental features. Some of these basic requirements are discussed in IEEE

Standard (IEEE 1993) Standard for Software Life Cycle Processes. This standard

describes the processes that are mandatory for the development of software and

specifies the activities that must be included in the life cycle model.

Most modern software development models, and certainly those following IEEE

Standard 1074, include some form of the basic phased model. It is therefore

important to understand the different phases and how they relate to one another.

Concept

Prototype

Requirements

Design

Implementation

Test

The rapid prototyping cycle

Figure 4: Rapid prototyping followed by the phase method.

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