The Life-Cycle of a System

This chapter discusses and explains the life-cycle of a system. It starts out saying “every man-made system has a life-cycle, even if it is not formally defined.” This is exactly correct and needs to be emphasized. The life-cycle stages include development, production, utilization, and retirement. Though, system engineering efforts are usually concentrated at the beginning, system engineering in still needed through-out the life of a system.

Summary

The Life-Cycle of a system consists of three aspects; the business aspect (business case), the budget aspect (funding), and the technical aspect (product) . System engineers must balance these aspects during the system life-cycle. During the system life-cycle, the system must proceed through a series of Decision Gates. Decision Gates are sometimes Reviews, or Milestones. The Decision Gates are approval events included in the project schedule. Entry and Exit criteria are defined for Decision Gates. Decision Gates need to address these three questions:

1. Does the project deliverable still satisfy the business case?

2. Is it affordable?

3. Can it be delivered when needed?

Every project has at least 2 decision gates, Authority to Proceed, and Final Acceptance. Typically there are many more.

The life-cycle of a system consists of these stages:

• Exploratory Research Stage o Studies new ideas, enabling technologies, and capabilities.

• Concept Stage o Refines and expands upon the studies, experiments, and engineering models pursued during the Exploratory Research Stage.

• Development Stage o Includes detailed planning, development, and Integration, Verification, and Validation (IV&V) activities.

• Production Stage o Produces or manufactures the system of interest.

• Utilization Stage o System is operated.

• Support Stage o Services are provided that enable the system to continue to operate.

• Retirement Stage o System is removed from operation.

Life-Cycle Approaches

The handbook summarizes the approaches to system engineering that are applied.

• Plan-driven Approach o Traditional paradigm of requirements->design->build->test->deploy. o Strengths are predictability, stability, repeatability, and high assurance.

• Incremental and Iterative Development Approach o Provides an initial capability followed by successive deliveries. o Strengths are velocity and adaptability

• Lean Development Approach o Based on a Lean Thinking. “Lean Thinking is a holistic paradigm that focuses on delivering maximum value to the customer minimizing wasteful practices.” In Lean Thinking, wasteful is defined as “work that adds no value to the product or service in the eyes of the customer.” o Strengths are adding value and reducing waste.

• Agile Development Approach o A tailoring process to shorten the project life-cycle by doing development steps out of sequence, while balancing the risk introduced. o Strengths are flexibility and adaptability.

The chapter continues by asking the question “What is Best for Your Organization?” This question is intended to get the reader to think.