Advantages Of Incremental Life Cycle Model

Published Date: 02 Nov 2017

In the field of information technology, software development life cycle plays a vital role from the beginning till the end of a software project. SDLC is a process of gathering requirements, understanding the needs, designing the system and delivering it to the user. The SDLC result will meet the expectations and the requirements of the customer, all the stages are pre-planned and testing methods are used to reduce the errors. The customers’ expectation reaches within the given time and the estimated cost. The stages of the SDLC are Feasibility, Design, Cording, Testing and maintenance.

Fig 1.1

1.1 Feasibility Study

Feasibility Study is the very first step of software or system development life cycle (SDLC). The main concept of feasibility is to see whether there is a feasible solution for the proposed project. The feasibility study is divided into three sections, they are;- Time Feasibility, Cost Feasibility, and Scope Feasibility.

Software’s which are built by using SDLC model should have better plans, otherwise the software may not be able to perform better. The software developing team or the developer need to always keep good interaction with the customer to find the facts and requirements. By analyzing the requirement it will be helpful to identify the problem.

Time Feasibility

Time Feasibility is to make sure that the given time is enough or not to complete a project. A agreement will be made between the developer and the customer that the project should be completed before the given time. The developer estimates the time period in order to consider the customers needs and the available resources.

Cost Feasibility

Cost feasibility is completing the project within the given budget, so the project holders must decide the correct budget for the project, or there will not be enough money to complete the project.

Scope Feasibility

Scope feasibility is to check whether the project holders can fulfill the functions requested by the customer. The developer has to analyze the customers’ expectations and what kind of software he is expecting from the software. The developer has to give his ideas and make the customer understand the project.

Time feasibility, Cost feasibility, and Scope feasibility are called as the triple constrain of the project, if any of this constrains fail the whole project is failed.

1.2 Requirement Gathering

The main purpose of requirement gathering is to consider about the project objective and decide what should be done in the next stages to satisfy the customer. If the developer gathers incorrect information, first it will affect the IT company, then the system will not be like the user wished, and the project will cost more.

Requirement Gathering can be done in different ways like observations, interviews, questioners, research and site visits.

Observations

By doing observations it can determine where, who, what, when, why, and the project will go through. The observer needs to get the permission from his/her supervisor or the manager to do the observation. The people who are involved in the observation should not interrupt the individuals or workers while working.

Advantages of observation

Can do work measurements.

Relatively inexpensive contrast with other methods.

Can observe perfectly what the employee effect is in difficult task.

The gathered can be very reliable.

Disadvantages of observation

People may perform differently when being observed.

Some works not always do the same way.

The given time will be wasting if the observation not succeeds.

Interviews

Conducting interviews are very important because the analyst can directly contract the system and the potential users. The analyst should prepare his/her self before the interview, and it is a must to establish a report with the interview. The analyst has to gather maximum information as much as possible, the analyst is allowed to ask questions in different methods.

Types of interviews

Unstructured interview- An interview that is conducted with only a general goal or subject in mind and with few if any specific questions.

Structured interview- This means that interviewer has a specific set of questions to ask from the interviewer.

Open-ended questions- Question that allows the interviewer to respond in any way that seems appropriate.

Close-ended questions- A question that restricts answer to either specific choices of short direct responses.

There are some rules when conducting an interview, first selecting the interviewees and learn about in person prior to the interview, then the analyst has to prepare the interview by selecting questions which is going to be asked in front of them.

Questioners

It is a requirement gathering method by questioning the person who is related with the task system, through this method we can collect many useful information to design or implement the project, and it is a special purpose document that allows the analyst to collect information and opinion from respondents. There are many types of questioners. They are-

Free Format Questioner / Unstructured

A question that is asked and the respondent records the answer in the space provided after the question

Ex- Are you satisfied with the current system?

………………………………………………………………………………………………………………………………………………………………………………………………

Fixed Format Questioner / Structured

Fixed format questioner is a questioner containing questions that requires selecting an answer from pre-defined available responses.

Are you satisfied with the current system?

Yes No

Research and Site visits

Research and site visits is a method of requirement gathering by going some research guides and also can collect information by other websites which are related with our project.

Designing

System design is a process of defining the interface architecture, module and components to satisfy the specified the requirements. The developer has to make an analysis on the design of the system. Designing is done very carefully because due to a small error the software may damage. At this stage the design is described by including screen layouts, business rules, process diagrams, sand etc., and the outcome of this designing stage will come out with a collection of modules. The developer has to think a lot because the next stages are depending on this stage. Designing is the blue print for the solution.

There are different methods available to design such as

ER diagram (entity relationship)

DFD (data flow diagram)

UML (unified modeling languages)

Flow chart

Structure chart

Decision trees

Decision tables

Implementation

In implementation the selected designs are translated into codes, and the designed documents are translated it a machine readable codes. The programs are done by using common programming languages, and the designs are converted into a machine readable form. More time is taken for the cording step and involves number of errors. Programming tools are used such as

Compilers

Interpreters

Debuggers

Are used to translate and generate into codes. Different kind of programming languages are used such as JAVA, C++, and Pascal etc. according to the application the programming language is chosen.

Testing

After completing the coding the developer has to test the system to find out the errors, the subset of the domain used in the testing process is called the Test data set. The output of testing is the Test log document. There are different types of testing techniques which the developer use to find the errors in our software project they are;-

Unit 3

Unit 2

Unit 1Unit Testing – unit testing is a method of testing a particular unit individually. A unit is the smallest part of an application. This testing method is done by the programmer not by the tester. The testers who test the program need full information about the program.

The units are checked individually, first the programmer checks the unit 1 after he finishes unit 1 he moves on to the next unit.

Integration Testing – Integration testing is done by combining individual software units and testing it as groups, the integration testing comes after unit testing. This is the testing of the compile parts of an application to determine whether its working together correctly. The testing is done on small segments where errors are easier to find.

System Testing - The main focus of system testing is to make sure that the customer requirements are fulfilled. System testing is done after the integration testing is complete, and the system testing should test the non-functional and functional requirements of the software project.

Functional Testing – The functional testing provides a final assurance which the software meets all the functions on its behavior.

Acceptance Testing – It is the final method of testing which is based on the specification of the final user or the customer.

Black Box Testing - It also can be called as functional testing. It is a software testing method where the internal workings of the item which is being tested and that is not known by the tester, for ex;- in a black box testing of a software project the tester will only know the inputs and what would be the expected outcomes and the tester will not know how the program arrives at those outputs. The tester never examines the programing code and the tester does not need any further knowledge about the program other than its specifications

White Box Testing - White box testing is also known as glass box testing, clear box testing, structural testing and transparent box testing. White box testing is a testing method of testing software’s which tests the internal structure or working of an application. White box testing is an internal perspective of the system, and programming skills are used to design test cases, when testing the tester has to deal with the code and tester to look at the code to find the error or the malfunctioning code.

Incremental Life Cycle Model

It is the best choice to use Incremental life cycle model for this software project, because this is not such a large project incremental model suits the Auto Lanka Private LTD online website, if we continue with this model the developer will be able to finish this project in a small period of time and in a small budget, and the customer will meet his/her requirements. There are many advantages and some disadvantages in this model they are as follows.

Advantages of Incremental Life Cycle Model

The working software can be generated during the software life cycle.

Customer is able to respond to each built.

Flexibility is high.

The developer can do experiments with the delivered increments, while the other increments are being developed.

Initial delivery cost is lowered.

Easy to test.

Disadvantages of Incremental Life Cycle Model

Each stage of iteration is rigid and stages do not overlap.

Needs good planning and design.

Cost is higher than the waterfall model.

Needs a clear and complete definition of the entire system before it can be broken down and built incrementally

2. TASK O2

* How does the Spiral model overcome the limitations of the Waterfall cycle model and the incremental model? Explain by referring to the proposed system.

Waterfall Cycle Model

The waterfall model was the 1st process model introduced. It is also known as a Linear-sequential life cycle model, and this model is very easy to use and understand. In the waterfall model each phase should be completed fully before starting the next phase. At the finishing of each phase, a review is taken place to find out whether the project is on the correct path, and should or shouldn’t continue or discard the project. In this model phases do not overlap.

Stages of waterfall model

System/Information Engineering and Modeling

Software Requirements Analysis

Systems Analysis and Design

Code Generation

Testing

Maintenance

Fig 2.1 ref. ISTQB Exam Certification .com

Disadvantages of Waterfall Model

The mode is very weak for long and ongoing projects.

The risk is high

Once a software is in the testing stage, it is difficult to go back and change which was not done properly out in the concept stage.

It is not a good model for object-oriented and complex projects.

Incremental Model

Incremental model is an evolution of waterfall model. In incremental model the full requirement is divided into various builds, it means that multiple development stages take place in making the life cycle. When using the incremental model the first increment to be used is a core product. The core product is used by the customer, the designer uses a detailed documentation while designing. The customer uses the software and gets a good review about the software. A plan is developed for one to another increment, and the software product needs to meet the customers’ needs and requirements. There should be a better plan to do better modifications and maintenance to fulfill the customer needs. The software is developed in step by step manner.

Fig 2.2 ref. ISTQB Exam Certification .com

Disadvantages of Incremental Model

Each stage of iteration is rigid and stages do not overlap.

Needs good planning and design.

Cost is higher than the waterfall model.

Needs a clear and complete definition of the entire system before it can be broken down and built incrementally.

Spiral Model

The Spiral Model has a combined feature of Waterfall model and Prototyping Model. The spiral model is used mostly to implement large, expensive and complicated projects, and the spiral model is similar to the incremental model. The spiral models method is the process starts at the center point of the spiral and it splits up. The requirements will be understood less at the center and will successfully refine with each rotation around the spiral. When the length of the spiral increases the cost too will be increased. Requirements are gathered during the planning phase. A prototype is produced at the end of risk analyzing phase.

Fig 2.3 ref. ISTQB Exam Certification .com

Advantages of Spiral Model

Good choice for large and critical projects.

Software is produced early in the software life cycle.

Additional functions can be added at a later date.

Strong approval and documentation control.

Incremental model is the suitable model to Auto Lanka Private LTD online system than the Spiral model, because this is a small project, spiral model is taken for big projects. When seeing the cost side if we complete this project through Incremental model, the cost will be low, so the effective and efficient model for this project is Incremental model.

3. TASK 3

*Prepare a feasibility report to the proposed system and discuss its components. The report should consists of Introduction, purpose of the feasibility report, Project description, system functionality, Feasibility study (time, cost, scope, technical, Economic) conclusion and referencing.

Feasibility report for Auto Lanka Private LTD

By Mizal Mujahick

Table of Contents

Introduction…………………………………………………………………..17

Purpose……………………………………………………………………….17

Project Description………………………………………………………….17

System Functionality of Auto Lanka Private LTD………………….……18

Feasibility Study…………………………………………………….…..18-19

Time………………………………………………………..……….18

Cost…………………………………………………………...…….19

Scope………………………………………………………….…...18

Conclusion……………………………………………….…………..……18

Introduction

The following document describes feasibility study proposal for Auto Lanka Private LTD, it is a most recognized car sale company in Srilanka. They have many problems with the current system, and the manager has decided that they cannot continue with the current system if they continue they will end up in a big loss. So the manager has decided to implement a new system. So the new system makes both the companies and customers work easy, almost all the deals are done online.

Purpose

The purpose of this project is to generate an online system to Auto Lanka Private LTD, The developer has to first check whether he can hand over the project to the customer according to his/her requirements, first the developer has to check whether he can submit the project within the given time if it is not enough the developer has to request more time, next is the developer has to check with the budget, whether he can complete the project inside the given budget, and at last the developer has to check whether the customer is meeting his/her requirements, if not the developer has to give his/her ideas and make the project according to the customers’ requirements.

Project Description

Through this website customers are able to view many things, to get the latest updates about newly released vehicles, they can find vehicles according to their requirements, they can find the vehicle parts online, customer are able to get updates about motor shows, vehicles exhibition, vehicle parades and etc., customers are allowed to chat with each other, if the customers are conducting any shows about the vehicles they can advertise in our website.

System Functionality of Auto Lanka Private LTD

IF a Customer wants to buy or sell a vehicle through Auto Lanka Private LTD, the first thing they have to do is they have to create an account at the system with a valid phone number or email address, the customers will have to give their details, once the customer gives his/her details, a confirmation mail or text will be sent to your particular email address or phone number. After that the customer is able to advertise, buy or sell vehicles. Auto Lanka Private LTD has provided many facilities to satisfy the customers like, the ADD, DELETE and EDIT option when the customer adds an information he/she can edit or delete if they want to, next is the search option, it is located right at the top of our home page, through that the customers can search the vehicle to his/her requirements, customers can view advertisements about motor shows, vehicle exhibitions and etc…., if the customer needs to advertise in our website they can make the payments online. When there is a motor show, vehicle exhibition in the city the news will be sent to the customer via text or email, and also the customers get latest updates about vehicles. The customers are able to compare the prizes when buying or selling a vehicle.

Feasibility Study

Time Feasibility

Auto Lanka Private LTD has decided to give a time period of nine months to complete this project. Inside nine months the developer should submit the project, nine months is a good time period to complete this project. The developer has used the incremental model as a guide for the timeline. With the requirement gathering stage concluded the other four stages will each have just over a month to be done on schedule.

Cost Feasibility

Auto Lanka Private LTD has granted a budget of Rupees four hundred thousand to complete this project. This amount will face software life cycle which is divided into five stages:- requirements gathering, designing the website, implementing the website, testing the product, and maintenance. A large part of this budget will be taken for the maintenance of this project, and also a another big amount will be taken for the testing part of this project because when implementing this project the developer have to face several kind of testing to make quality assurance engineers.

Scope Feasibility

According to the information gathered by conducting different methods such as observations, Questionnaire, interviews, and the requirements are established by the client, as software developers now we are able to satisfy Auto Lanka Private LTD requirements.

Conclusion

Having successfully completed the feasibility report for Auto Lanka Private LTD, the time and budget given for this project is very reasonable. So it is impossible now that the project can be completed meeting the customer requirements.

4. TASK 04

*Assess the impact of Time, Cost and Scope feasibility criteria on systems investigation for the recommended solution.

These days developing software is not an easy task, when implementing software first the developer has to check whether the customer is meeting his/her requirements. Time, Cost and Scope feasibility are known as the triple constrains, if the customer and the developer are not satisfied with any of these, the project will result in a failure. During implementation of software, the developer should be able to explain his project in feasibility criteria, just to make it clear that the developer has a clear understanding about this project, because if the feasibility report is not correct, in the final step the project will end up in a failure.

Impact of Time Feasibility

Time Feasibility is developing a software inside the given time period. The customer and the developer should agree with the given time period, and if the developer did not submit the project inside the given time period it will damage the developers reputation.

Impact of Cost Feasibility

Once the time period is fixed for the project, the next important thing that follows is the cost feasibility, the client and the developer should come to an agreement with the budget. The developer should come to an settlement with the customer to complete the successfully. The developer and the customer should be honest when coming to a settlement and fixing the budget for the project.

Impact of Scope Feasibility

Scope feasibility is to check whether the customer is meeting his/her requirements, when implementing a software the first main thing the developer has to check whether the customer is meeting his/her requirements, if the software is not meeting the customers’ requirements, then the developer should implement the software according to the customers’ requirements, sometimes there are chances the customer would reject the project. Therefore the customers’ requirements should be analyzed first before going to the other stages of the software project.