1. Introduction To software engineering
CS 560
Lecture 1

2. Software engineering Introduction to software engineering
If you don’t understand it, you can’t program it.
If you can’t measure it, you can’t improve it.

3. Software engineering Definition:
SE covers technical aspects of building software systems, along with management issues such as directing teams, scheduling, and budgeting.
More and more systems are software controlled
National infrastructures: utilities, communication, navigation
Entertainment: music, movie/television, games
Residential: community design, landscaping
Science/Data Collection: biology, chemistry, physics, engineering, …
Social Interactions: , social networks, text messaging

4. Software engineering vs. Computer Science
Study design of algorithms, languages, hardware and software architectures, and complexities such as space and time.
Foundation based on mathematics and theory.
Why does it work?
Software Engineering:
Study design of creating high quality software that provides a solution to a given problem using controlled, systematic, and efficient techniques.
Foundation based on problem solving.
How does it work?

5. Software engineering
The economies of ALL developed nations are dependent on software.
Software represents a significant fraction of GDP in all developed countries.
1997: $149 billion
1.7% U.S. GDP
2014: $1 trillion
6% U.S. GDP
The use of software has also increased the productivity of other industries.
15% increase in all U.S. labor productivity from 2004 to 2012.
Software accounted for $101 billion in overall production in 2012.

6. Software engineering Software Jobs:
1990: 778,000
1995: 1,083,000
2010: 2,095,000
2014: 2,501,000
2016: 3,360,000
Software jobs growing faster than any other jobs.
2014: 2.2% of all U.S. employment
Software industry now directly responsible for ~4.2 million U.S. jobs
Software industry employment grows on average by 3.1% Every Year.
Average salary for new employees in the software industry: ~$60k
Average salary per person in the U.S.: ~$30k

7. Software costs Software costs often dominate computer system costs.
The costs of software on a PC are often greater than the hardware cost.

8. Software costs
A number of fundamental problems with the process of software development were identified:
Software was never completed, even after further investment had been made.
Removing flaws from “completed” software can take a considerable amount of time
The functionality of the software seldom matched the requirements of the end-users.
Once created, software was almost impossible to maintain.

9. Software costs
Software costs more to maintain than it does to develop. For systems with a long life, maintenance costs may be several times development costs.

10. Software Engineering Body of Knowledge

11. Software Engineering vs. “other” engineering
How is software engineering different than other types of engineering?
Exists entirely on and bounded by the rules of hardware.
CPU has four processing cores
Only two environmental sensors
Silicon and magnetic data storage
Software logic is not bounded by physical laws
Software gives the ability to make a world where the developer defines the rules.
What’s stopping you from replicating your own thought process using software?
Capacity to incorporate massive complexity
Few thousand lines of code for a mobile phone application
~2 billion lines of code for all Google Internet services
Communication between different types of environments, hardware, operating systems, etc.
Does not have problems due to product aging
All software (currently) is an abstraction of manipulation of voltage levels in semiconductors. Basically, the software tells hardware switches to turn “on” and “off”, and those rules don’t change based on software age.

12. Software Engineering Why is software engineering difficult?
You need to understand the problem domain
Problems for developing an autonomous robot
Problems for developing a web based data storage software
You need to understand the software domain
Domain specific software for robotic movement
Domain specific software for network traffic analysis
Software is formal
Functional requirements determine the software to be created
Software languages are bound by rules
Real world is informal
There is no precise statement of what a client may want from a software development team
Software engineering includes discovering a solution for a real-world problem

13. Software Engineering Computer Scientist:
Proves theorems about algorithms, designs languages, defines knowledge representation schemes, etc.

14. Software Engineering Software Engineer:
Creates the design for the real-world problem

15. Software Engineering Software Developer:
Generates the code for the real-world problem

16. Software Engineering
Software engineering is concerned with cost- effective software development.
First determine the needs of the client.
These needs/requirements may change over time.
Then design, construct, test, add features to the software system, and repeat.
Each member of the CS 560 project teams will be providing roles computer scientist, software engineer, and software developer.

17. Software Engineering
Role of the software engineer: (Each member of the project team should be involved with these roles)
Research (CS) – Seek new principles and processes by employing mathematical and scientific concepts, experimental techniques, and inductive reasoning.
Design (SE) – Select methods and materials to satisfy technical requirements and to meet performance specifications.
Development (SD) – Apply results of research to useful purposes. Creative application of new knowledge may result in a working software prototype.
Construction (SE) – Determine procedures that will economically and safely yield the desired software product.
Management (SE) – Responsible for deciding how resources are used, project team management, determining feasibility, and resolving problems.

18. Frequently asked questions about software engineering
What are the key challenges facing software engineering?
Coping with increasing diversity of software demands
Demands for reduced delivery times
Developing trustworthy software
Working with a diverse project team

19. Essential attributes of good software
Maintainability:
Software should be written so that it can evolve to meet the changing needs of the customers.
Critical since software change is an inevitable
Dependability and Security:
Characteristics such as reliability, security, and safety should be included in software engineering and design.
Efficiency:
Software shouldn’t make wasteful use of system resources such as memory and CPU cycles.
Acceptability:
Software must be acceptable to the type of users for which it is designed.
It must be understandable, usable, and compatible with other systems they use.

20. Software engineering diversity
There are many different types of software systems.
There is no universal set of software techniques that is applicable to all of these.
Ex: Techniques for building the embedded software system for autonomous robots versus techniques for building software systems used for metadata harvesting.
The software engineering methods and tools used depend on:
The type of application being developed
The requirements of the client
The background of the development team
In this class, the teams will be diverse, and the client’s requests may change over time.

21. Feasibility study
Analysis of the project in the form of a preliminary study and documentation
Overview of the proposed project and goals
Preliminary requirements
Functional, non-functional, user, system
Estimations of project scope and time
Breaking the project down into different tasks
Requirements gathering, software modeling/development languages, documentation, testing, organizational approach, etc.
Technical feasibility
Evaluate whether the proposed project will perform adequately based on requirements
Schedule feasibility
Assess the duration of the project
How much time to complete each task
How/When/Where to meet as a project group or subgroup
Progress Visibility
Risk Analysis