Requirements Engineering Process in Software Engineering

Requirements Engineering is the process of identifying, eliciting, analyzing, specifying, validating, and managing the needs and expectations of stakeholders for a software system.

In this article, we'll learn about its process, advantages, and disadvantages.

What is Requirements Engineering?

A systematic and strict approach to the definition, creation, and verification of requirements for a software system is known as requirements engineering. To guarantee the effective creation of a software product, the requirements engineering process entails several tasks that help in understanding, recording, and managing the demands of stakeholders.

Requirements Engineering Process

1. Feasibility Study
2. Requirements elicitation
3. Requirements specification
4. Requirements for verification and validation
5. Requirements management

1. Feasibility Study

The feasibility study mainly concentrates on below five mentioned areas below. Among these Economic Feasibility Study is the most important part of the feasibility analysis and the Legal Feasibility Study is less considered feasibility analysis. 

1. Technical Feasibility: In Technical Feasibility current resources both hardware software along required technology are analyzed/assessed to develop the project. This technical feasibility study reports whether there are correct required resources and technologies that will be used for project development. Along with this, the feasibility study also analyzes the technical skills and capabilities of the technical team, whether existing technology can be used or not, whether maintenance and up-gradation are easy or not for the chosen technology, etc.
2. Operational Feasibility: In Operational Feasibility degree of providing service to requirements is analyzed along with how easy the product will be to operate and maintain after deployment. Along with this other operational scopes are determining the usability of the product, Determining suggested solution by the software development team is acceptable or not, etc. 
3. Economic Feasibility: In the Economic Feasibility study cost and benefit of the project are analyzed. This means under this feasibility study a detailed analysis is carried out will be cost of the project for development which includes all required costs for final development hardware and software resources required, design and development costs operational costs, and so on. After that, it is analyzed whether the project will be beneficial in terms of finance for the organization or not. 
4. Legal Feasibility: In legal feasibility, the project is ensured to comply with all relevant laws, regulations, and standards. It identifies any legal constraints that could impact the project and reviews existing contracts and agreements to assess their effect on the project's execution. Additionally, legal feasibility considers issues related to intellectual property, such as patents and copyrights, to safeguard the project's innovation and originality.
5. Schedule Feasibility: In schedule feasibility, the project timeline is evaluated to determine if it is realistic and achievable. Significant milestones are identified, and deadlines are established to track progress effectively. Resource availability is assessed to ensure that the necessary resources are accessible to meet the project schedule. Furthermore, any time constraints that might affect project delivery are considered to ensure timely completion. This focus on schedule feasibility is crucial for the successful planning and execution of a project.

2. Requirements Elicitation

It is related to the various ways used to gain knowledge about the project domain and requirements. The various sources of domain knowledge include customers, business manuals, the existing software of the same type, standards, and other stakeholders of the project. The techniques used for requirements elicitation include interviews, brainstorming, task analysis, Delphi technique, prototyping, etc. Some of these are discussed here. Elicitation does not produce formal models of the requirements understood. Instead, it widens the domain knowledge of the analyst and thus helps in providing input to the next stage. 

Requirements elicitation is the process of gathering information about the needs and expectations of stakeholders for a software system. This is the first step in the requirements engineering process and it is critical to the success of the software development project. The goal of this step is to understand the problem that the software system is intended to solve and the needs and expectations of the stakeholders who will use the system.

Several techniques can be used to elicit requirements, including:

• Interviews: These are one-on-one conversations with stakeholders to gather information about their needs and expectations.
• Surveys: These are questionnaires that are distributed to stakeholders to gather information about their needs and expectations.
• Focus Groups: These are small groups of stakeholders who are brought together to discuss their needs and expectations for the software system.
• Observation: This technique involves observing the stakeholders in their work environment to gather information about their needs and expectations.
• Prototyping: This technique involves creating a working model of the software system, which can be used to gather feedback from stakeholders and to validate requirements.

It's important to document, organize, and prioritize the requirements obtained from all these techniques to ensure that they are complete, consistent, and accurate.

3. Requirements Specification

This activity is used to produce formal software requirement models. All the requirements including the functional as well as the non-functional requirements and the constraints are specified by these models in totality. During specification, more knowledge about the problem may be required which can again trigger the elicitation process. The models used at this stage include ER diagrams, data flow diagrams(DFDs), function decomposition diagrams(FDDs), data dictionaries, etc. 

Requirements specification is the process of documenting the requirements identified in the analysis step in a clear, consistent, and unambiguous manner. This step also involves prioritizing and grouping the requirements into manageable chunks.

The goal of this step is to create a clear and comprehensive document that describes the requirements for the software system. This document should be understandable by both the development team and the stakeholders.

Several types of requirements are commonly specified in this step, including

1. Functional Requirements: These describe what the software system should do. They specify the functionality that the system must provide, such as input validation, data storage, and user interface.
2. Non-Functional Requirements: These describe how well the software system should do it. They specify the quality attributes of the system, such as performance, reliability, usability, and security.
3. Constraints: These describe any limitations or restrictions that must be considered when developing the software system.
4. Acceptance Criteria: These describe the conditions that must be met for the software system to be considered complete and ready for release.

To make the requirements specification clear, the requirements should be written in a natural language and use simple terms, avoiding technical jargon, and using a consistent format throughout the document. It is also important to use diagrams, models, and other visual aids to help communicate the requirements effectively.

Once the requirements are specified, they must be reviewed and validated by the stakeholders and development team to ensure that they are complete, consistent, and accurate.

4. Requirements Verification and Validation

Verification: It refers to the set of tasks that ensures that the software correctly implements a specific function. 

Validation: It refers to a different set of tasks that ensures that the software that has been built is traceable to customer requirements. If requirements are not validated, errors in the requirement definitions would propagate to the successive stages resulting in a lot of modification and rework. The main steps for this process include:

1. The requirements should be consistent with all the other requirements i.e. no two requirements should conflict with each other.
2. The requirements should be complete in every sense.
3. The requirements should be practically achievable.

Reviews, buddy checks, making test cases, etc. are some of the methods used for this.

Requirements verification and validation (V&V) is the process of checking that the requirements for a software system are complete, consistent, and accurate and that they meet the needs and expectations of the stakeholders. The goal of V&V is to ensure that the software system being developed meets the requirements and that it is developed on time, within budget, and to the required quality.

1. Verification is checking that the requirements are complete, consistent, and accurate. It involves reviewing the requirements to ensure that they are clear, testable, and free of errors and inconsistencies. This can include reviewing the requirements document, models, and diagrams, and holding meetings and walkthroughs with stakeholders.
2. Validation is the process of checking that the requirements meet the needs and expectations of the stakeholders. It involves testing the requirements to ensure that they are valid and that the software system being developed will meet the needs of the stakeholders. This can include testing the software system through simulation, testing with prototypes, and testing with the final version of the software.
3. Verification and Validation is an iterative process that occurs throughout the software development life cycle. It is important to involve stakeholders and the development team in the V&V process to ensure that the requirements are thoroughly reviewed and tested.

It's important to note that V&V is not a one-time process, but it should be integrated and continue throughout the software development process and even in the maintenance stage.

5. Requirements Management

Requirement management is the process of analyzing, documenting, tracking, prioritizing, and agreeing on the requirement and controlling the communication with relevant stakeholders. This stage takes care of the changing nature of requirements. It should be ensured that the SRS is as modifiable as possible to incorporate changes in requirements specified by the end users at later stages too. Modifying the software as per requirements in a systematic and controlled manner is an extremely important part of the requirements engineering process.

Requirements management is the process of managing the requirements throughout the software development life cycle, including tracking and controlling changes, and ensuring that the requirements are still valid and relevant. The goal of requirements management is to ensure that the software system being developed meets the needs and expectations of the stakeholders and that it is developed on time, within budget, and to the required quality.

Several key activities are involved in requirements management, including:

1. Tracking and controlling changes: This involves monitoring and controlling changes to the requirements throughout the development process, including identifying the source of the change, assessing the impact of the change, and approving or rejecting the change.
2. Version control: This involves keeping track of different versions of the requirements document and other related artifacts.
3. Traceability: This involves linking the requirements to other elements of the development process, such as design, testing, and validation.
4. Communication: This involves ensuring that the requirements are communicated effectively to all stakeholders and that any changes or issues are addressed promptly.
5. Monitoring and reporting: This involves monitoring the progress of the development process and reporting on the status of the requirements.

Requirements management is a critical step in the software development life cycle as it helps to ensure that the software system being developed meets the needs and expectations of stakeholders and that it is developed on time, within budget, and to the required quality. It also helps to prevent scope creep and to ensure that the requirements are aligned with the project goals.

Tools Involved in Requirement Engineering

• Observation report
• Questionnaire ( survey, poll )
• Use cases
• User stories
• Requirement workshop
• Mind mapping
• Roleplaying
• Prototyping

Advantages of Requirements Engineering Process

• Helps ensure that the software being developed meets the needs and expectations of the stakeholders
• Can help identify potential issues or problems early in the development process, allowing for adjustments to be made before significant 
• Helps ensure that the software is developed in a cost-effective and efficient manner
• Can improve communication and collaboration between the development team and stakeholders
• Helps to ensure that the software system meets the needs of all stakeholders.
• Provides an unambiguous description of the requirements, which helps to reduce misunderstandings and errors.
• Helps to identify potential conflicts and contradictions in the requirements, which can be resolved before the software development process begins.
• Helps to ensure that the software system is delivered on time, within budget, and to the required quality standards.
• Provides a solid foundation for the development process, which helps to reduce the risk of failure.

Disadvantages of Requirements Engineering Process

• Can be time-consuming and costly, particularly if the requirements-gathering process is not well-managed
• Can be difficult to ensure that all stakeholders' needs and expectations are taken into account
• It Can be challenging to ensure that the requirements are clear, consistent, and complete
• Changes in requirements can lead to delays and increased costs in the development process.
• As a best practice, Requirements engineering should be flexible, adaptable, and should be aligned with the overall project goals.
• It can be time-consuming and expensive, especially if the requirements are complex.
• It can be difficult to elicit requirements from stakeholders who have different needs and priorities.
• Requirements may change over time, which can result in delays and additional costs.
• There may be conflicts between stakeholders, which can be difficult to resolve.
• It may be challenging to ensure that all stakeholders understand and agree on the requirements.

Stages in Software Engineering Process

Requirements engineering is a critical process in software engineering that involves identifying, analyzing, documenting, and managing the requirements of a software system. The requirements engineering process consists of the following stages:

• Elicitation: In this stage, the requirements are gathered from various stakeholders such as customers, users, and domain experts. The aim is to identify the features and functionalities that the software system should provide.
• Analysis: In this stage, the requirements are analyzed to determine their feasibility, consistency, and completeness. The aim is to identify any conflicts or contradictions in the requirements and resolve them.
• Specification: In this stage, the requirements are documented in a clear, concise, and unambiguous manner. The aim is to provide a detailed description of the requirements that can be understood by all stakeholders.
• Validation: In this stage, the requirements are reviewed and validated to ensure that they meet the needs of all stakeholders. The aim is to ensure that the requirements are accurate, complete, and consistent.
• Management: In this stage, the requirements are managed throughout the software development lifecycle. The aim is to ensure that any changes or updates to the requirements are properly documented and communicated to all stakeholders.
• Effective requirements engineering is crucial to the success of software development projects. It helps ensure that the software system meets the needs of all stakeholders and is delivered on time, within budget, and to the required quality standards.

Conclusion

As the project develops and new information becomes available, the iterative requirements engineering process may involve going back and reviewing earlier phases. Throughout the process, stakeholders in the project must effectively communicate and collaborate to guarantee that the software system satisfies user needs and is in line with the company's overall goals.

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Article Tags :

• Software Engineering