How a task network is defined for a software engineering project?

The task network is a useful mechanism for depicting inter task dependencies and determining the critical path. When more people are working on a software engineering project, tasks and sub-tasks have their own inter-dependencies and also as the number of people increases, the development activities and tasks are performed in parallel. These concurrent tasks must be coordinated so that so that they will be complete when later tasks require their work products.

What is a task network?
It is also known as activity network. It is a graphic representation of how the tasks are flowing in a software engineering project. There is a pattern and a sequence that is followed by tasks. This task network can be used as a mechanism or a way to know this sequence and pattern of the tasks that can act as an input to an automated project scheduling tool.

On a macroscopic view, task network depicts the software engineering tasks. On a microscopic view, each and every task in the task network is expanded. For a concept development project, task network includes the following tasks:
- Concept Scoping
- Concept Planning
- Technology and Risk Assessment (It constitutes three tasks).
- Proof of Concept
- Concept Implementation (It constitutes three tasks).
- Integrate the three tasks which constitutes concept implementation.
- Customer Reaction

Software engineering activities are concurrent in nature. This nature leads to scheduling requirements. The project manager should keep in mind the following points to ensure continuous progress:
- He should determine the inter-task dependencies.
- He should be aware of tasks that lie on critical path which means the tasks that should be completed on schedule if project has to completed on schedule.

How to define a task set for a software project?

The process model is defined by a set of tasks which enables the software team to define, develop and support computer software irrespective of whether the software team uses an incremental model, linear sequential method, an evolutionary model. Nearly every project will have a different task set which means that no single task is appropriate for all projects.

The set of tasks that a simple project uses or needs is different from the set of tasks that is needed by a large complex system. A collection of task sets should be defined to meet the needs of different types of projects by the software process that is effective.

The task set that is developed should be distributed on a project time line. Task set depends on the type of the project and the rigor with which the software team decides to do the work. Different kind of projects encountered by software organizations are:

- Application enhancement projects
- Content development projects
- New application development projects
- Application maintenance projects
- Re-engineering projects

The factors that affect the choice of the task set for a single project type are:
- project size.
- number of potential users.
- critical nature of mission.
- longevity of the application.
- requirements stability.
- maturity of applicable technology.
- embedded and non-embedded characteristics.
- performance constraints.
- project staff.
- re-engineering factors.

For example, in concept development projects, major tasks followed are:
- Concept scoping
- Preliminary concept planning
- Technology risk assessment
- Concept proof
- Implementation concept
- Customer reaction

Task Set of Project Planning - Estimating resources

The software development effort requires to estimate resources. There are three categories of software resources:
- people
- reusable software components
- development environment.

A resource has four characteristics:
- resource description
- availability
- time when resource will be required
- time duration in which resource can be applied.

TYPES OF RESOURCES ARE:

- Human Resources
The organizational position and specialty are specified. The location for each human resource is specified. After determining the estimate of development effort, the number of people required for a software project is determined.

- Reusable Software Resources
Re-usability is the creation and reuse of software building blocks which are called components and are cataloged for easy reference and standardized for easy application and validated for easy integration. Four software resource categories that are considered are :

Off the shell components
Full experience components
Partial experience components
New components

- Environmental Resources
Software engineering environment includes hardware and software. Hardware involves tools to produce work products. The software team require access to hardware elements developed by other engineering teams.

What is the task set for project planning? What is software scope and feasibility?

Steps that are involved for project planning are:
- Establish a project scope.
- Determine the feasibility.
- Analyze the risks.
- Define the required resources like human resources required, reusable software resources and environmental resources.
- Estimate the cost and effort by decomposing the problem, developing two or more estimates using size, function points, process tasks or use cases and reconciling the estimates.
- Developing a project schedule which includes establishing a meaningful task set, defining a task network, using scheduling tools to develop a timeline chart and defining a schedule for tracking mechanisms.

Software scope are functions and features that are delivered to end users, input and output data, content that is presented to users and the performance, constraints, interfaces and reliability that bound the system. Using either of the two techniques are used to define scope:
- set of use cases developed by end users.
- narrative description of software scope developed after communication with stakeholders.

Project feasibility is important but a consideration of business need is even more important. It does no good to build a high tech system or product that no one wants.

Project Management - The W5HH Principle

Barry Bohem suggested an approach that addresses project objectives, milestones and schedules, responsibilities, management and technical approaches and required resources. This is called W5HH principle. The questions that are answered in this principle are:

- Why is the system being developed?
- What will be done by When?
- Who is responsible for a function?
- Where are they organizationally located?
- How will the job be done technically and managerially?
- How much of each resource is needed?

WHY IS THE SYSTEM BEING DEVELOPED?
It enables the parties to assess the validity of business reasons for the software work. It justifies the expenditure of people, time, and money.

WHAT WILL BE DONE?
It specifies the task set required for the project.

WHEN WILL IT BE DONE?
It helps to determine the project schedule. It helps in determining when tasks are conducted and when milestones are reached.

WHO IS RESPONSIBLE FOR A FUNCTION?
It helps to accomplish the role and responsibilities of each member of the software team.

WHERE ARE THEY ORGANIZATIONALLY LOCATED?
The software team does not contain all the roles and responsibilities. The customers, users and stakeholders also have responsibilities.

HOW WILL THE JOB BE DONE TECHNICALLY AND MANAGERIALLY?
The management and technical strategy of project is defined once the scope of the product is established.

HOW MUCH OF EACH RESOURCE IS NEEDED?
It helps in deriving estimates based on the answers to the above questions.

Defining a Task Set For The Software Project

No single task is appropriate for all projects. The set of tasks that would be appropriate for a large, complex system would likely be perceived as overkill for a small, relatively simple software product. Therefore, an effective software process should define a collection of task sets, each designed to meet the needs of different types of projects.

To develop a project schedule, a task set must be distributed on the project time line. The task set will vary depending upon the project type and the degree of rigor with which the software team decides to do its work. Most software organizations encounter the following projects :
- Concept Development projects : These projects are initiated to explore some new business concept or application of some new technology.
- New Application Development projects : These projects are undertaken as a consequence of a specific customer request.
- Application Enhancement projects : These projects occur when existing software undergoes major modifications to function, performance, or interfaces that are observable by the end user.
- Application Maintenance projects : The projects that correct, adapt, or extend existing software in ways that may not be immediately obvious to the end-user.
- Re engineering projects : These projects are undertaken with the intent of rebuilding an existing system in whole or in part.

DEFINING A TASK NETWORK
Individual tasks and subtasks have inter dependencies based on their sequence. A task network, also called an activity network, is a graphic representation of the task flow for a project. It is sometimes used as a mechanism through which task sequence and dependencies are input to an automated project scheduling tool. The concurrent nature of software engineering activities leads to a number of important scheduling requirements. Because parallel tasks occur asynchronously, the planner must determine intertask dependencies to ensure continuous progress toward completion. In addition, the project manager should be aware of those tasks that lie on the critical path.