01
  • Module Overview
  • Course Outline
  • Introduction
  • Section 1
  • 1.1
  • 1.2
  • 1.3
  • 1.4
  • 1.5
  • 1.6
  • Section 2
  • 2.1
  • 2.2
  • 2.3
  • Key Points
  • Glossary

  • Module Overview

    On completion of this module the student should be able to:

    ● Understand the nature of the key systems and software engineering processes and activities necessary for the development and deployment of successful commercial computer systems
    ● Compare the characteristics of the range of modern software lifecycle models and approaches in relation to the suitability of each for different types of computer system development.
    ● Understand the role of project management and software quality activities in the development of successful computer systems
    ● Understand the basic processes involved in software maintenance and evolution (including for legacy systems, business analysis and process modelling)
    ● Apply basic requirements engineering techniques to the development and documenting of the specification and highlevel modelling of functional and nonfunctional computer system requirements.


    Syllabus

    💡 Systems and Software Engineering Processes and Activities
    💡 Software Life Cycles
    💡 Requirements Engineering


    💡 Reading Material
    X

    Systems and Software Engineering Processes and Activities

    ● Basic stages in the systems development lifecycle: project initiation and definition, user and system requirements
    ● definition, analysis and design, implementation and testing, deployment (including user documentation and training) and maintenance, disposition
    ● Conceptual foundations of OO systems modelling: use case model, design model, deployment model, implementation model, test model
    ● Software project management principles and core activities, role of the project manager, nature of a project plan, project monitoring activities, concept of project risk
    ● Software quality concepts: definitions of software quality, the need for quality systems, distinction between process and product quality, core product quality attributes
    ● Software testing concepts: testing stages, acceptance and system testing principles: functional testing, usability testing, reliability testing, security testing, performance testing
    ● Software maintenance and evolution: the nature of software maintenance, maintenance activities and managing the maintenance process, the software re-engineering process and common approaches such as business analysis and as-is process model creation; legacy system maintenance
    X

    Software Lifecycle

    ● Principles that characterise successful software development practice
    ● Traditional (waterfall) lifecycle model
    ● V-Model
    ● Iterative lifecycles, e.g. spiral, RAD, prototyping
    ● Agile life cycles: principles and concepts; examples of agile process models, e.g. DSDM, SCRUM,FDD
    ● Agile methods and practices, e.g. extreme programming/XP
    X

    Requirements Engineering

    ● The role of the requirements engineer
    ● The requirements engineering process
    ● System stakeholders
    ● Requirements elicitation
    ● Requirements classification: functional; non-functional; requirements classification frameworks, e.g. FURPS+
    ● Business Analysis Modelling: the use of business use case models and activity diagrams to capture as-is business processes
    ● Requirements modelling: the use of use case analysis to capture and document requirements
    ● Use case descriptions, specifying test criteria in use cases
    ● Initial domain modelling
    X

    Reading Material

    Sommerville, I. (2015). Software Engineering. Pearson
    ● Available in the library and to purchase from the book shop
    ● This is an essential book that you will need access to.
    ● This book will be useful on subsequent modules in later years
  • Course Outline image

  • Topics covered

    ● Professional software development
    ● What is meant by software engineering.
    ● Software engineering ethics
    ● A brief introduction to ethical issues that affect software engineering.


    Software Engineering

    ● The economies of ALL developed nations are dependent on software.
    ● More and more systems are software controlled
    ● Software engineering is concerned with theories, methods and tools for professional software development.
    ● Expenditure on software represents a significant fraction of GNP in all developed countries.


    Software Costs

    ● Software costs often dominate computer system costs. The costs of software on a PC are often greater than the hardware cost.
    ● Software costs more to maintain than it does to develop. For systems with a long life, maintenance costs may be several times development costs.
    ● Software engineering is concerned with cost-effective software development.


    Software project failure

    ● Increasing system complexity
    ● As new software engineering techniques help us to build larger, more complex systems, the demands change.
    ● Systems have to be built and delivered more quickly; larger, even more complex systems are required;
    ● Systems have to have new capabilities that were previously thought to be impossible.
    ● Failure to use software engineering methods
    ● It is fairly easy to write computer programs without using software engineering methods and techniques. Many companies have drifted into software development as their products and services have evolved. They do not use software engineering methods in their everyday work. Consequently, their software is often more expensive and less reliable than it should be.
    ● Please click the video link below regarding the factors of IT Project fail?
    🎥 Why IT project fail? ( data source: Gary Calwall, 2011)



    Succeeded: is completed & on time & on budget with all features and functions as specified.
    Failed: is cancelled before completion, never implemented or scrapped following installation.
    Challenged: is completed & operational but over budget, late & with fewer features & functions than initially specified.


    Critical success factors

    Critical success factor: A factor which is deemed crucial to the success of IT project.
    Project success factors report from Standish group, 2013.
    1. Executive management support
    2. User involvement
    3. Optimization
    4. Skilled resources
    5. Project management expertise
    6. Agile process
    7. Clear business objectives
    8. Emotional maturity
    9. Execution
    10. Tools and infrastructure
    X

  • Professional software development

  • Product specification


    Generic products
    ● The specification of what the software should do is owned by the software developer and decisions on software change are made by the developer.
    🎥 Generic software products (YouTube, 2015)


    Customised products
    ● The specification of what the software should do is owned by the customer for the software and they make decisions on software changes that are required.
    Software products


    Generic products
    ● Stand-alone systems that are marketed and sold to any customer who wishes to buy them.
    ● Examples – PC software such as graphics programs, project management tools; CAD software; software for specific markets such as appointments systems for dentists.


    Customised products
    ● Software that is commissioned by a specific customer to meet their own needs.
    ● Examples – embedded control systems, air traffic control software, traffic monitoring systems.
    🎥 Software - Generic & Custom-written applications
    (data source: YouTube: nick Jackson, 2011)
    X
    X
  • Essential attributes of good software

    3. Efficiency:
    ● Software should not make wasteful use of system resources such as memory and processor cycles.
    ● Efficiency therefore includes responsiveness, processing time, memory utilisation, etc.


    4. Acceptability
    ● Software must be acceptable to the type of users for which it is designed.
    ● This means that it must be understandable, usable and compatible with other systems that they use.
    1. Maintainability:
    ● Software should be written in such a way so that it can evolve to meet the changing needs of customers.
    ● This is a critical attribute because software change is an inevitable requirement of a changing business environment
    🎥 Maintenance - Georgia Tech - Software Development Process


    2. Dependability and security:
    ● Software dependability includes a range of characteristics including reliability, security and safety.
    ● Dependable software should not cause physical or economic damage in the event of system failure.
    ● Malicious users should not be able to access or damage the system.
    🎥 System Dependability
    🎥 System security


  • Importance of software engineering

    ● More and more, individuals and society rely on advanced software systems.
    ● We need to be able to produce reliable and trustworthy systems economically and quickly.
    ● It is usually cheaper, in the long run, to use software engineering methods and techniques for software systems rather than just write the programs as if it was a personal programming project.
    ● For most types of system, the majority of costs are the costs of changing the software after it has gone into use.
    Software Engineering

    Software engineering is an engineering discipline that is concerned with all aspects of software production from the early stages of system specification through to maintaining the system after it has gone into use.


    Engineering discipline
    ● Using appropriate theories and methods to solve problems bearing in mind organizational and financial constraints.


    All aspects of software production
    ● Not just technical process of development. Also project management and the development of tools, methods etc. to support software production.
  • Software engineering diversity

    There are many different types of software system and there is no universal set of software techniques that is applicable to all of these.


    The software engineering methods and tools used depend on the type of application being developed, the requirements of the customer and the background of the development team.
    Software process activities

    ● Software specification, where customers and engineers define the software that is to be produced and the constraints on its operation.
    ● Software development, where the software is designed and programmed.
    ● Software validation, where the software is checked to ensure that it is what the customer requires.
    ● Software evolution, where the software is modified to reflect changing customer and market requirements.


    General issues that affect software

    Heterogeneity
    ● Increasingly, systems are required to operate as distributed systems across networks that include different types of computer and mobile devices.


    Business and social change
    ● Business and society are changing incredibly quickly as emerging economies develop and new technologies become available. They need to be able to change their existing software and to rapidly develop new software.


    Security and trust
    ● As software is intertwined with all aspects of our lives, it is essential that we can trust that software.


    Scale
    ● Software has to be developed across a very wide range of scales, from very small embedded systems in portable or wearable devices through to Internet-scale, cloud-based systems that serve a global community.
  • Application Types

    Stand-alone applications
    ● These are application systems that run on a local computer, such as a PC.
    ● They include all necessary functionality and do not need to be connected to a network.


    Interactive transaction-based applications
    ● Applications that execute on a remote computer and are accessed by users from their own PCs or terminals.
    ● These include web applications such as e-commerce applications.


    Embedded control systems
    ● These are software control systems that control and manage hardware devices.
    ● Numerically, there are probably more embedded systems than any other type of system.
    🎥 Introduction to Embedded Control Systems
    (video data source: Rvceet, 2012)


    Batch processing systems
    ● These are business systems that are designed to process data in large batches. They process large numbers of individual inputs to create corresponding outputs.


    Entertainment systems
    ● These are systems that are primarily for personal use and which are intended to entertain the user.


    Systems for modelling and simulation
    ● These are systems that are developed by scientists and engineers to model physical processes or situations, which include many, separate, interacting objects.


    Data collection systems
    ● These are systems that collect data from their environment using a set of sensors and send that data to other systems for processing.


    Systems of systems
    ● These are systems that are composed of a number of other software systems.
  • Software engineering fundamentals

    ● Some fundamental principles apply to all types of software system, irrespective of the development techniques used:
    ● Systems should be developed using a managed and understood development process. Of course, different processes are used for different types of software.
    ● Dependability and performance are important for all types of system.
    ● Understanding and managing the software specification and requirements (what the software should do) are important.
    ● Where appropriate, you should reuse software that has already been developed rather than write new software.


    Internet software engineering

    ● The Web is now a platform for running application and organizations are increasingly developing web-based systems rather than local systems.
    ● Web services (discussed in Chapter 19) allow application functionality to be accessed over the web.
    ● Cloud computing is an approach to the provision of computer services where applications run remotely on the ‘cloud’.
    ● Users do not buy software buy pay according to use.


    Web-based software engineering

    ● Web-based systems are complex distributed systems but the fundamental principles of software engineering discussed previously are as applicable to them as they are to any other types of system.
    ● The fundamental ideas of software engineering apply to web-based software in the same way that they apply to other types of software system.


    Software reuse
    ● Software reuse is the dominant approach for constructing web-based systems. When building these systems, you think about how you can assemble them from pre-existing software components and systems.


    Incremental and agile development
    ● Web-based systems should be developed and delivered incrementally. It is now generally recognized that it is impractical to specify all the requirements for such systems in advance.


    Service-oriented systems
    ● Software may be implemented using service-oriented software engineering, where the software components are stand-alone web services.


    Rich interfaces
    ● Interface development technologies such as AJAX and HTML5 have emerged that support the creation of rich interfaces within a web browser.

  • Software engineering ethics

  • ● Software engineering involves wider responsibilities than simply the application of technical skills.
    ● Software engineers must behave in an honest and ethically responsible way if they are to be respected as professionals.
    ● Ethical behaviour is more than simply upholding the law but involves following a set of principles that are morally correct.


    Issues of professional responsibility

    Confidentiality
    ● Engineers should normally respect the confidentiality of their employers or clients irrespective of whether or not a formal confidentiality agreement has been signed.


    Competence
    ● Engineers should not misrepresent their level of competence. They should not knowingly accept work which is out with their competence.


    Intellectual property rights
    ● Engineers should be aware of local laws governing the use of intellectual property such as patents, copyright, etc. They should be careful to ensure that the intellectual property of employers and clients is protected.


    Computer misuse
    ● Software engineers should not use their technical skills to misuse other people’s computers. Computer misuse ranges from relatively trivial (game playing on an employer’s machine, say) to extremely serious (dissemination of viruses).
  • ACM/IEEE Code of Ethics

    ● The professional societies in the US have cooperated to produce a code of ethical practice.
    ● Members of these organisations sign up to the code of practice when they join.
    ● The Code contains eight Principles related to the behaviour of and decisions made by professional software engineers, including practitioners, educators, managers, supervisors and policy makers, as well as trainees and students of the profession.


    Rationale for the code of ethics

    ● Computers have a central and growing role in commerce, industry, government, medicine, education, entertainment and society at large.
    ● Software engineers are those who contribute by direct participation or by teaching, to the analysis, specification, design, development, certification, maintenance and testing of software systems.
    ● Because of their roles in developing software systems, software engineers have significant opportunities to do good or cause harm, to enable others to do good or cause harm, or to influence others to do good or cause harm.
    ● To ensure, as much as possible, that their efforts will be used for good, software engineers must commit themselves to making software engineering a beneficial and respected profession.
  • The ACM/IEEE Code of Ethics

    Software Engineering Code of Ethics and Professional Practice

    ACM/IEEE-CS Joint Task Force on Software Engineering Ethics and Professional Practices

    PREAMBLE

    The short version of the code summarizes aspirations at a high level of the abstraction; the clauses that are included in the full version give examples and details of how these aspirations change the way we act as software engineering professionals. Without the aspirations, the details can become legalistic and tedious; without the details, the aspirations can become high sounding but empty; together, the aspirations and the details form a cohesive code.

    PREAMBLE

    Software engineers shall commit themselves to making the analysis, specification, design, development, testing and maintenance of software a beneficial and respected profession.

    In accordance with their commitment to the health, safety and welfare of the public, software engineers shall adhere to the following Eight Principles:

    1. PUBLIC - Software engineers shall act consistently with the public interest.
    2. CLIENT AND EMPLOYER - Software engineers shall act in a manner that is in the best interests of their client and employer consistent with the public interest.
    3. PRODUCT - Software engineers shall ensure that their products and related modifications meet the highest professional standards possible.
    4. JUDGMENT - Software engineers shall maintain integrity and independence in their professional judgment.
    5. MANAGEMENT - Software engineering managers and leaders shall subscribe to and promote an ethical approach to the management of software development and maintenance.
    6. PROFESSION - Software engineers shall advance the integrity and reputation of the profession consistent with the public interest.
    7. COLLEAGUES - Software engineers shall be fair to and supportive of their colleagues.
    8. SELF - Software engineers shall participate in lifelong learning regarding the practice of their profession and shall promote an ethical approach to the practice of the profession.

  • Key Points

    ● Software engineering is an engineering discipline that is concerned with all aspects of software production.
    ● Essential software product attributes are maintainability, dependability and security, efficiency and acceptability.
    ● The high-level activities of specification, development, validation and evolution are part of all software processes.
    ● The fundamental notions of software engineering are universally applicable to all types of system development.
    ● There are many different types of system and each requires appropriate software engineering tools and techniques for their development.
    ● The fundamental ideas of software engineering are applicable to all types of software system.
    ● Software engineers have responsibilities to the engineering profession and society. They should not simply be concerned with technical issues.
    ● Professional societies publish codes of conduct which set out the standards of behaviour expected of their members.

  • Glossary

    ADEHIOPSW

    A

    ACM

    The Association for Computing Machinery (ACM) is an international learned society for computing.

    data source: https://en.wikipedia.org/wiki/Association_for_Computing_Machinery

    AJAX

    Ajax stands for Asynchronous Javascript And Xml. AJAX is about updating parts of a web page, without reloading the whole page.

    data source: http://www.w3schools.com/ajax/ajax_intro.asp

    Return to Top

    D

    Dependability

    The dependability of a system is an aggregate property that takes into account the system's safety, reliability, avaiability, security and other attributes. The dependability of a system reflects the extent to which it can be trusted by its users.

    data source: Sommerville I. 2016 "Software Engineering" 10th Edition. Pearson Pp.762.

    Return to Top

    E

    Embedded system

    A software system that is embedded in a hardware device (e.g. the software system in a mobile phone). Embedded systems are usually real-time systems and so have to respond in a timely way to events occurring in their environment.

    data source: Sommerville I. 2016 "Software Engineering" 10th Edition. Pearson Pp.762.

    Return to Top

    H

    HTML5

    HTML5 is a markup language for describing web documents (web pages). HTML stands for HyperText Markup Language; HTML5 is supported in all modern browsers.

    I

    IEEE

    The Institute of Electrical and Electronics Engineers (IEEE, pronounced I triple E) is a professional association with its corporate office in New York City and its operations center in Piscataway, New Jersey. It was formed in 1963 from the amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers. Today, it is the world's largest association of technical professionals with more than 400,000 members in chapters around the world. Its objectives are the educational and technical advancement of electrical and electronic engineering, telecommunications, computer engineering and allied disciplines.

    data source: https://en.wikipedia.org/wiki/Institute_of_Electrical_and_Electronics_Engineers

    Information system

    An informtion system is a system of communication between people. Information system are systems involved in the gathering, processing, distrution and use of information.

    data source: Beynon-Davies, P. 2000, "Information systems: An introduction to informatics in organisations",2nd Edition, Palgrave. Pp.583.

    Internet

    A set of interconnected computer newtworks distributed around the globe

    data source: Beynon-Davies, P. 2000, "Information systems: An introduction to informatics in organisations",2nd Edition, Palgrave. Pp.584.

    Return to Top

    O

    Open source

    An approach to software development where the fundamental abstractions in the system are independent objects. The same type of abstraction is used during specfication, design and development.

    data source: Sommerville I. 2016 "Software Engineering" 10th Edition. Pearson Pp.766

    Return to Top

    P

    Project management

    The process of planning for, organising and controlling projects.

    data source: Beynon-Davies, P. 2000, "Information systems: An introduction to informatics in organisations",2nd Edition, Palgrave. Pp.589.

    Return to Top

    S

    Security

    The ability of a system to protect itself against accidental or deliberate intrusion. Security includes confidentiality, integrity and avaiablility.

    data source: Sommerville I. 2012 "Software Engineering" 10th Edition. Pearson Pp.771.

    Software development

    often used as another name for the software process; originally coined to refer to the watherfall model of the software process.

    data source: Sommerville I. 2016 "Software Engineering" 10th Edition. Pearson Pp.771.

    Return to Top

    W

    Web service

    An independent software component that can be accessed through the Internet using standard protocols. It is completely self-contained without external dependencies. XML-based standards such as SOAP (Standard Object Access Protocol) for web service information exchange, and WSDL (Web Service Definition Language), for the definition of web service interfaces, have been developed. However, the REST approach may also be used for web service implementation.

    data source: Sommerville I. 2016 "Software Engineering" 10th Edition. Pearson Pp.774.

    Wilderness weather system

    A system to collect data about the weather conditions in remote areas.

    data source: Sommerville I. 2016 "Software Engineering" 10th Edition. Pearson Pp.775.

    WWW

    World Wide Web. A set of standards for hypermedia documentation. It now has become synonymous with the Internet.

    data source: Beynon-Davies, P. 2000, "Information systems: An introduction to informatics in organisations",2nd Edition, Palgrave. Pp.595.

    Return to Top