CS 577b Software Engineering II -- Introduction 16 September 2018 Systems Engineering CS 577b Software Engineering II Supannika Koolmanojwong Ref: Systems Engineering Body of Knowledge (V0.75) © 2002-6 USC Center for Software Engineering

Outline Differences between SwE and SE Systems Thinking SE and Management © 2011 USC-CSSE

Definition – Systems Engineering “an interdisciplinary approach and means to enable the realization of successful systems” (INCOSE 2011). It focuses on holistically and concurrently understanding stakeholder needs; exploring opportunities; documenting requirements; and synthesizing, verifying , validating, and evolving solutions while considering the complete problem, from system concept exploration through system disposal © 2011 USC-CSSE

Design Thinking © 2011 USC-CSSE

Definition - System “An interacting combination of elements to accomplish a defined objective. These include hardware, software, firmware, people, information, techniques, facilities, services, and other support elements.” [INCOSE] © 2011 USC-CSSE

System of Interest system domain being considered Systems engineers generally refer to their system of interest as “the system” Helps in defining a system context Relationships between SOIs Systems that work directly with it Systems which influence it in some way © 2011 USC-CSSE

Types of Systems Systems thinking is applied to help better understand what those systems do and how they do it People can observe, reason about it, but cannot exercise control © 2011 USC-CSSE

Types of Systems Purely human in nature By creating artifacts, people gain some kind of control over, or protection from, the natural world © 2011 USC-CSSE

Types of Systems purely technical systems By creating artifacts, people gain some kind of control over, or protection from, the natural world © 2011 USC-CSSE

Types of Engineered Systems (1/3) Products and Product Systems Product: hardware, software, information, personnel, an agreement or contract to provide something Product systems: systems in which products are developed and delivered to the acquirer for the use of internal or external user For product systems the ability to provide the necessary capability must be defined in the specifications for the hardware and software, or the integrated system that will be provided to the acquiring enterprise Services and Service Systems Enterprises and Enterprise Systems © 2011 USC-CSSE

Types of Engineered Systems (2/3) Products and Product Systems Services and Service Systems Service: A service can be simply defined as an act of help or assistance. E.g. transport, communications, protection, data processing Services: are processes, performances, or experiences that one person or organization does for the benefit of another – such as custom tailoring a suit, driving a limousine A service system is one that provides outcomes for a user without necessarily delivering hardware or software products to the service supplier The use of service systems reduces or eliminates the need for acquirers to obtain capital equipment and software in order to obtain the capabilities needed to satisfy users Enterprises and Enterprise Systems © 2011 USC-CSSE

Types of Engineered Systems (3/3) Products and Product Systems Services and Service Systems Enterprises and Enterprise Systems An enterprise is one or more organizations or individuals sharing a definite mission, goals, and objectives to offer an output such as a product or service An enterprise system consists of a purposeful combination of interdependent resources that interact with 1) each other and 2) their environment(s), to achieve goals through a complex web of interactions distributed across geography and time Enterprise systems create and deliver products and services © 2011 USC-CSSE

Outline Differences between SwE and SE Systems Thinking Valerdi, R. and Rouse, W. B., When Systems Thinking Is Not a Natural Act, 5th IEEE Systems Conference, San Diego, CA, April, 2010. Peter Senge's 11 Laws of Systems SE and Management © 2011 USC-CSSE

Systems Thinking http://en.wikipedia.org/wiki/Systems_thinking © 2011 USC-CSSE

http://sdm.mit.edu/news/news_articles/webinar_082211/20110822_Valerdi.pdf © 2011 USC-CSSE

http://www.ashpfoundation.org/lean/CMS3.html © 2011 USC-CSSE

Four Things Every Engineer Should Know About Systems Thinking Systems thinking is not a natural act Educational system is the biggest inhibitor to systems thinking Systems thinking can be taught (but not to everyone, unfortunately) The best way to develop your systems thinking abilities is through experiential learning Valerdi, R. and Rouse, W. B., When Systems Thinking Is Not a Natural Act, 5th IEEE Systems Conference, San Diego, CA, April, 2010. © 2011 USC-CSSE

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Inhibitors to Systems Thinking over-specialization tasks a short time horizon personality trait of individuals rigid, hierarchical organizations combination of factors such as cognitive complexity, internal locus of control, occupational level, educational level, and interest education system © 2011 USC-CSSE

The best way to develop your systems thinking abilities is through experiential learning Peter Senge is an influential systems thinker (MIT) 11 Laws of Systems http://www.ashpfoundation.org/lean/CMS3.html © 2011 USC-CSSE

11 Laws of Systems Today's problems come from yesterday's solutions The harder you push, the harder the system pushes back Behavior grows better before it grows worse Don’t bully your way out of the tough problem. Take time to think through. Think about consequences and unintended consequences. Too often our solutions strike back to create new problems. © 2011 USC-CSSE

4. The easy way out, leads back in 5 4. The easy way out, leads back in 5. The cure can be worse than the disease. 6. Faster is slower. The easy and familiar solution is not only ineffective, it can be addictive and dangerous. it might even induce dependency. Remember that the optimal rate of growth or change is far slower than the fastest growth © 2011 USC-CSSE

7. Cause and effect are not always closely related in time and space. 8. Small changes can produce big results -- but the areas of highest leverage are often the least obvious © 2011 USC-CSSE

9. You can have your cake and eat it too -- but not all at once either-or” choices are the product of static thinking Fail to consider that basic improvements  having it all if we are willing to wait for one while we focus on the other. Invest in the development of new skills and methods. © 2011 USC-CSSE

10. Dividing an elephant in half does not produce two small elephants must view the whole system (individual parts and their interactions) that generated the issue difficult to practice. Most organizational designs keep people from seeing important interactions. © 2011 USC-CSSE

11. There is no blame we tend to blame outside circumstances for our problems. Systems thinking says there is no “outside” . . . that we are part of a system that includes the cause of the problems. Hence, the cure lies in your relationship with your “enemy.” © 2011 USC-CSSE

Outline Differences between SwE and SE Systems Thinking SE and Management © 2011 USC-CSSE

Life Cycle Models © 2011 USC-CSSE

Incremental and evolutionary development Concept, Development, Production, and Utilization (including Support) or “CDPU.” © 2011 USC-CSSE

1. Prespecified Single-Step 2. Prespecified Sequential models When requirements are pre-specifiable and stable, they enable a strong, predictable process. When requirements are emergent and/or rapidly changing, they often require expensive rework if they lead to undoing architectural commitments. © 2011 USC-CSSE

3.Evolutionary Sequential model system develops rapidly to initial operational capability and is upgraded based on operational experience. Pure agile software development, Rapid fielding Strength: allowing quick-response capabilities in the field using this model may prove expensive concept © 2011 USC-CSSE

4. Evolutionary overlapped deferring the next increment until the desired new technology is mature enough to be added, or until other enablers become available © 2011 USC-CSSE

5. Evolutionary concurrent the systems engineers handling the change traffic and rebaselining the plans and specifications for the next increment, while keeping the development stabilized for the current increment © 2011 USC-CSSE

Organizing Teams to Perform Systems Engineering © 2011 USC-CSSE

Systems Engineering Competency Model The Academy of Program/Project & Engineering Leadership (APPEL), NASA © 2011 USC-CSSE

© 2011 USC-CSSE