Cell Structure and Function

What is Software Engineering?

• Software involves carefully organized instructions and code written by developers across various computer languages.
• Engineering applies scientific and practical knowledge to invent, design, build, maintain, and improve frameworks and processes.
• Software Engineering is an engineering branch focused on evolving software products using defined scientific principles, techniques, and procedures.
• The goal of software engineering is to produce effective and reliable software products.

Need for Software Engineering

• Software Engineering handles large projects without issues for corporations.
• It manages costs by planning and reducing unnecessary elements by software engineering programmers.
• Developing software using a software engineering technique will help save time.
• Companies are responsible for delivering software products on schedule and addressing any defects needing reliable software.
• Effectiveness stems from adhering to software standards during creation.

Characteristics of Good Software

• Operational characteristics include budget, efficiency, usability, dependability, correctness, functionality, safety, and security.
• Transitional characteristics include interoperability, reusability, portability, and adaptability.
• Maintenance characteristics include flexibility, maintainability, modularity, and scalability.

Nature of Software

• System software provides a platform for other software.
• System software interacts with hardware and application software.
• Examples of System Software: macOS, Linux, Android, and Microsoft Windows.
• Application software is designed to carry out a specific user task.
• Examples of Application Software: Social media apps, Gaming apps, Word processors, Multimedia apps, and Banking apps.
• Engineering and Scientific Software enhances engineering functions and handles tasks in real-time.
• Engineering and Scientific Software requires high accuracy, evolves complex formulas, and analyzes data.
• Weather prediction and stock market apps are examples of Engineering and Scientific Software.
• Embedded software resides within systems or products to control features for end-users.
• Examples of Embedded Software: Switches, Routers, Digital cameras, Washing machines, and Traffic control systems.
• Web applications are client-server programs running on web browsers.
• Web apps can range from simple linked hypertext files to complex applications presenting information with text and graphics.
• Examples of Web Applications: Online forms, Shopping carts, Gmail, Yahoo, Photo editing, and File conversion tools.
• Artificial Intelligence Software utilizes nonnumerical algorithms to solve complex problems.
• Applications of Artificial Intelligence Software: Robotics, Expert systems, Pattern recognition, Artificial neural networks, and Game playing.
• Examples of Artificial Intelligence Software: Google Cloud, Azure studio, Tensor Flow, and Salesforce.

Software Process

• A software process includes activities and related results to produce software.
• Software engineers primarily carry out these activities.
• Software Specification defines the software functionality and operational constraints.
• Software Development produces software that meets specified requirements.
• Software Validation ensures the software meets customer requirements.
• Software Evolution adapts software to meet changing client needs.

Software Engineering – SDLC Models

• SDLC models include: Waterfall, RAD, Spiral, V-model, Incremental, Agile, Iterative, and Bigbang models.

Generic Process Model

• Software process develops quality products through technical and management rules.
• The Generic Process Model describes the software development process.
• It is used as a base in most other software models.

Process Framework Activities

• The framework for generic process includes: Communication, Planning, Modelling, Construction & Deployment
• Communication starts with dialogue between the customer and developer.
• Developers gather project requirements with users.
• Communication with stakeholders determines objectives, software requirements, and features.
• Planning involves complete estimation, scheduling, and tracking for project development.
• Planning discusses the work plan, technical risks, resource needs, work products, and work schedule.
• Modelling develops a practical model for better project understanding to get a better understanding of the project.
• Modelling includes complete requirement analysis and design which might use algorithms and flowcharts.
• The algorithm is a step-by-step problem solution.
• A flowchart shows a complete program flow diagram.
• Changes are implemented in the modelling step, if needed.
• Construction involves code generation and testing such as coding details using a programming language.
• Testing verifies the correctness of the coding flow and ensures the program provides the desired output.
• Deployment delivers the product to the customer and gathers feedback.
• If needed, changes are required for improvements to the quality of software based on demands.

Umbrella Activities

• Umbrella activities occur throughout a software process for better management.
• Actions for software project tracking compare project progress with the plan to maintain schedules.
• Risk management analyzes any potential risks affecting the software product's quality.
• Software Quality Assurance (SQA) maintains software quality through specific actions on product quality.
• Technical Reviews assess errors and corrections at each activity stage.
• Software Configuration Management (SCM) manages configuration changes in the software.
• Reusability Management backs up reusable work items and makes reusable software components.
• Work Product Preparation and Production creates models, documents, logs, forms, and lists.

Framework Activities - Communication Details

• For small projects, communication involves a phone call to the stakeholder.
• Requirements should be discussed, noted down, and organized.
• Mail the stakeholder for approval.
• For large projects, arrange a live meeting, complete a feasibility study, perform requirement analysis and develop specification documents.

Identifying Task Sets

• A task set is the "actual work" needed to meet an objective of each engineering module.
• Communication Activity task set involves: Prepare a list of stakeholders, Organize a meeting for stakeholders, Discuss / Finalize requirements, and list issues.

About SDLC Process

• SDLC (Software Development Life Cycle) is a process for developing software.
• SDLC develops quality software as per customer requirements.
• SDLC Process can improve relationships, offer basic planning/scheduling/estimation, provide a standard set of activities, increase development speed, maintain project tracking, decrease project risk, and decide entry/exit criteria at each phase.

SDLC Phase #1 - Requirement Analysis & Planning

• This phase is led by a Product manager, Business Analyst, or team members.
• The aim is to understand the customer’s overall aim, purpose and exact requirements.
• Market research with customer interviews and surveys is carried out.
• A Software Requirement Specification (SRS) document is created.
• Risk assessments are identified during planning of a project schedule, and cost estimates are developed.
• Online shopping applications should consider shopping cart and discount modules, user interfaces, along with other features.

SDLC Phase #2 - Design

• This phase is led by the Product manager and UI/UX Designer team.
• High-level design includes the Software Architecture and brief descriptions of each module.
• Flow Diagrams, Database tables, Interface relationships, and Algorithm.
• Low-level design includes Input & Output details, Rough paper designs, listings of error messages in the user interface, etc.
• Documentation is documented in DDS “Design Document Specification”.

SDLC Phase #3 - Implementation

• This phase is conducted by a Developer or Programmer.
• Predefined coding guidelines or discussions with the management team must be followed.
• Suitable programming languages, databases, and programming are used.

SDLC Phase #4 - Testing

• This is conducted by the QA team or the Tester.
• It performs integration, black box, white box, system, regression, performance and acceptance testing.
• The testing team starts testing the functionality of the entire system verifying that the application works.
• Bugs/defects are reported to developers (who fix the bugs and then send it back to QA).

SDLC Phase #5: Deployment & Maintenance

• This phase is conducted by the Project Manager, Operation, or Production support team.
• The final software is released to the market or deployed to the customer after certification, and no bugs.
• Support Managers in the Maintenance fix any issues that come up or implement any updates.

SDLC Models

• Some SDLC Models include Waterfall, RAD, Spiral, V-Model, Incremental, Agile, Iterative, and the Big Bang model.

Waterfall Model

• Winston Royce introduced the Waterfall Model in 1970.
• The Waterfall Model is a linear sequential development that was the first SDLC Model.
• Each waterfall phase must complete before beginning the next one, with phased output being next phase input.
• This model is named "Waterfall Model" because its diagram cascades.

When to use Waterfall model?

• Use when requirements are constant and not regularly changed and applications aren't complicated.
• Use when the project is short & simple.
• Use when consistent, unchanging tools/technologies are used with well-prepared available resources.

Waterfall Models Phases

• In the Requirement Analysis phase - understand and document customer requirements: what the system will do in common language.
• Software Requirement Specification (SRS) document is created and is a contract between customers and the development team.
• In the Design Phase - gathered requirements are converted into suitable designs describing overall software architecture with high and detailed design.
• High level design include Algorithm, Flow charts, Decision tree, Database design etc. Low Level Design include Rough Paper Design, User Interface Components, etc.
• Programming languages, databases, or hardware & software requirements are finalized documented as a Software Design Document (SDD).
• The Development Phase uses software design to translate into source code and has code developed into small programs called units after that are integrated.
• Unit testing is done in development to check the performance of each working module.
• In the Testing Phase, testers performs testing activities to meet the client requirements and report anomalies.
• Integration testing is done after combining all the modules.
• A Test case & Test reports are generated during testing.
• In the Deployment & Maintenance Phase product is deployed releasing patches, better versions, and maintaining.

Advantages of Waterfall

• Simple, easy to understand/use, and works well for smaller projects.
• One phase must be completed before the next phase of development.
• Requirements are clear and well understood providing documentation of process and results.

Disadvantages of Waterfall

• There can be high amounts of risk and uncertainty because errors can only be fixed during the phase.
• Not suitable for projects with reqs. Changing requirements, and is more difficult and does not suit object oriented projects
• There is no client feedback cannot be included with the ongoing development phase.

Iterative Development Model

• SDLC Cycle includes some Requirements & analysis, development of the first version of S/W, and the creation of new versions when there are changes.
• An iterative project can be finalized and deployed.

When to use Iterative Model?

• When project size is large, when new tech. Is learnt by dev. team, the requirements are defined and changes are expecte.

Iterative Phases

• The Requirement Gathering & Analysis phase understands the requirement.
• A system analyst the checks that the requirement can be satisfied within the budget.
• A Design Phase overall software architecture and a Coding Phase where software designs lead to specific source code using Programmers using suitable databases..
• A testing Phase: Where testers perform testing activities to ensure client requirements are met. Black/white/grey box test methods are widely used.
• Review Phase: The software is and estimated and then reviewed and considered for an update in the next iteration.
• Deployment and Maintainence: The product is set for customer use. Potential bugs or other problems will be dealt with and solved in this phase.

Advantages of Iterative

• Easier testing and debugging during smaller iterations.
• Parallel development is possible and adaptive to the project changing needs.
• Shorten design time and identified risks are resolved during an iterative phase.

Disadvantages of Iterative

• Not suited for smaller project and will require more resources.
• Project can be longer and costly due to the design changing repeatedly.

Incremental Process Model

• Is characterized by dividing requirements into Standalone modules
• Each Module receives the needed treatment of phases
• Every version is additive
• It can continue untill every objective of the System can be achieved

Use of Incremental Model

• It provides priorized requirements first it needs for those req. To be clear and specific. Also when the product must first be tested
• It is useful when not all project teams are skilled properly - cost effective for companies and web apps

Model Phases

Reqs. / Analysis

• Business Analyst And Product Manager extract customer wants from them
• This is crucial Role of This model

Design Phase

• The overall architecture design is based on level of importance
• It could use Dataflow and others for its purpose

Implementation Phase

• Designs are translated through a language code which will then be compiled into a database

Testing phase

The output software is tested among both internal and external users

• and if needed then it could use several testing methods to improve

Disadvantages of Incremental

• Need full requirements collected up front
• Each interaction has to happen properly because they do not overlap

Advantages

• Flexible and inexpensive
• Simple to manage handled

Evolutionary Process Model

• The "Successive Versions Model" combines some elements of iterative and incremental models to reduce dev. Costs; but to also achieve a similar end version
• Deliver product module by module to the customer.
• Its used in complex project when changes are required to modules

The 3 types Prototyping, spiral concurrent:

The spiral

• The spiral phases are: - Reqs, analysis, and other prototypes.
• The spiral includes identification of all risks with customer evaluation.
• And finally, design a prototype of model.

Concurrent Development Model

• SDLC (Communication, Design, coding) are often integrated in the process.
• Its characterized by changes to a projects activity start with some modelling of code

Advantages of Evolutionary

• It is useful checked stages and to get the same type of experiments using already developed software
• The overall outcome leads to reductions in cost.

Disadv.

Its difficult to divide in several smaller parts, as it requires clear communication

Software Engineering

Prototyping method:

• Is the generation of a prototype used to clarify reqs.
• It can also verify that the process of delivery works

Prototyping

• Is not fully complete: only used for implantation (or TOY implementation of a system)
• Iterative, trial based where its best to generate software before further building

Examples of prototyping vs. actual application

• It should follow a design thats simple to use

Use

Applied - customer does know project specifications, before the software, requires iteration

Advantages

Does not require a clear machine system because the product is flexible

Disadvantages

• A slower process
• Clients are far more involved
• Often expensive w respect to time and money

Spiral Model

Spiral includes prototyping iterative Waterfall Boehm 86 model Risk driven SDLC, series increments

Microsoft ex. Uses spirarl

Use

• When the project is complex. There should not be economic priorities at play.

Pases

• requirements, planning, communication cost analysis
• Risk with prototype + feedback is also reviewed during iteration

Adv

• Allows for prototypes + custommer feedback

Dis

Complex, need analysis, risk means potential of expensive spirals

Concurrent Model

• Evoultionary model known as concurrent engineering ("done at the same time")
• ALL sw dl process transition from state for activities ex Inactive is no work state And Underdevelopment is some activity under performance

Advantages

Test is very fast, all sw process is easy

Dis

Better communication is not all the time a guarantee - will need to remember the various statuses

About Agile Model

• The Ability of Changes from people+tech
• Its incremental / iterative

Works

• Diving of reqs, and deliver sw reqs is rapid.
• Can have direct collaboration with customers as this occurs from 2 to 3 weeks

TRADITIONAL

Req analysis, Design implement test and maintain vs iterative

• It can increase the project time + span; however results in satisfying the customer a lot sooner.

Agile Principles

• Deliver soft at any point to provide the customer service, - frequent SHORT

• developer work close togethr with open communication - create a positive environment and attention

• The art of good result is by using max result - develop and test the sw as needed

Adv

• Its acceptable to change at any point the process

Dis.

Improper doc as its alliterative makes any project hard to read. Its also too depended on the customer which means it cant give proper direction

7 Needs

• Market Demand Opportunity in need Customer Request Tech Advance Legal /Eco/ Social

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