{ Software Engineering } Theorical notes

Software Theorical notes

1. Introduction - Software engineering

Software is

Instructions that provides desired features, function, and performance
Data structures that enable the programs to adequately manupulate information
Doc that describes the operation and use of the programs
Software is developed and engineered / not manufactured in the classical sense
Does not wear out, it does deteriorate
Domains - System, Application, Engineering/Scientific, Embedded, product-line, web&mobile apps, and AI software

Wear VS Deterioration

As time goes, changes are made, so that it increases failure rate because of side effects
Curve is dynamic as a developer makes changes and fixs such errors
Why must software change?
- must be ‘adapted’ to meet the needs of new computing environments or techs
- must be ‘enhanced’ to implement new business requirements
- must be ‘extended’ to make interoperable with other more modern systems or db
- mush be ‘re-architected’ to make it viable

What is software engineering?

Defenition : IEEE defines software engeering is the application of a sysmetic, disciplined, quantifiable // (체계적이고, 규율화, 수량화 될 수 있는) approach to the development, operation, and maintainance of software; that is the application of engineering to software
Layers: 1. A quality focus 2. Process 3. Methods, 4. Tools
Process Framework Activities : Communication, planning, modeling (analysis of requirements, and design), construction (code generation, and testing), and finally deplyment
Umbrella Activities(보호활동) : Tracking and control, risk management, quality assurance, review…etc

Essence of software engineering practice

Understand the problem(communication and analysis)
- Who are the stakeholders?
- What are the unknown? (what data, functions, and features are required to solve the problem?)
- Can the problem be separated into smaller parts, and it results in easier to understand?
- Can the problem be represented graphically? (analysis model can be created?)
Plan a solution (modeling and design)
- Is there existing software that implements the data, functions, and features that are required?(reference)
- Similar solutions are reusalbe?
- Can subproblems be defined?
- Can you represent a solution in a manner that leads to effective implementation?
Carry out plan (code generation)
- Does the solution confirm to the plan?
- Has the design and code been reviewed, or better, have correctness proofs been applied to algorithm?
Examine result for accuracy (testing & quality assurance)
- Has a reasonable testing strategy been implemented?
- Has the software been validated against all stakeholder requirements?

Hooker’s General Priniciples

The Reason It All Exists
KISS (Keep It Simple, Stupid!) – design simple as it can be.
Maintain the Vision
What you produce, others will consume
Be open to the future
Plan ahead for reuse
Think! - placing thought before action produce results

How it all starts - safehome begins

Some business need

to correct a defect
to adapt a legacy system to a changing business environment
to extend the functions and features
to creat a new product, service, or system

2. Process Model

Process Model Flow

Linear Process Flow : Communication → planning → Modeling → Implementation → Contruction → Deployment
Iterative Process Flow : ((Communication → planning) → (Modeling) → Implementation → Contruction) → Deployment
Evolutionary Process Flow : Communication → planning → Modeling → Implementation → Contruction → Deployment ( Increment released )
Parallel Process Flow

5. Human Aspects of Software Engineering

Traits of Successful Software Engineers

Sense of individual responsibility
Acutely aware of the needs of team members and stakeholders
Honest about design flaws and offers constructive criticism
Resilient under pressure
Heightened sense of fairness
Attention to detail
Pragmatic adapting software engineering practices based on the circumtances at hand

Effective software team attributes

Sense of purpose, involvement, trust, improvement, and diversity of team member skill sets

Project Factors affecting team structure

Difficulty of the problem to be solved
Too huge program size in lines of code or function points
Meeting times (team lifetime)
Degree to which the problem can be modularized
Required quality and reliablility(시스템 신뢰성) of the system to be built
Rigidity of the delivery date
Degree of communication required for the project

Agile teams

Emphasize ‘Individual competency’ coupled with group collabortion (Every members has the ability to make a decision)
Communication among developers and stakeholders is crucial
Planning is constrained only by business requirements and organizational standards
Team is “self-organizing.”
- Adaptive team structures
- Significant autonomy

Team members must have trust in one another. The distribution of skills must be appropriate to the problem. Mavericks may have to be excluded from the team, if team cohesiveness is to be maintained.

Team is “self-organizing.” • An adaptive team structure. • Planning is kept to a minimum. • Team select its own approach constrained by business requirements and organizational standards.

Highly depend on engineer’s ability
Value grows as team size increases or when a team is geographically separated
Benefits from it must be weighted against the threat of exprosure of crucial information.

Team decision making complication

Has unintented consequences on another project object e.g. law
Different views of the problem can lead to different conclusion about the way forward

Factors affecting global software dev teams

Distance complicates communication / accentuates the need for coordination
Communication enhances collaboration
Collaboration improves coordination
Coordination reduces Barrier and complexity
Barrier and complexity attenuates communication ….

6. Project management concepts

Four P’s : People, Product, Process, and Project
Stakeholders Senior managers, Project managers, Practitioners : who deliver the technical skills that can upgrade a product or apps

Team Leaders practices

Good Model the way
Inspire and shared vision - Motivate team members involving stakeholders early
Challenge the process - encourage team members while learning from their failures
Enable others to act - by sharing decision making and goal setting
Encourage the heart - build team spirit