INCOSE Chapter 3

Quality Characteristic ISO/IEC/IEE 15288

Inherent characteristic of a product, process, or system related to a requirement. QCs are how stakeholders will judge the quality of a system.

Affordability Analysis

The balance of system performance, cost, and schedule constraints over the system life while satisfying mission needs in concert with strategic investments and organizational needs.

A system is affordable when?

It can be developed to meet its requirements within cost and schedule constraints.

Technology Readiness Level (TRL)

• Scale that evaluates the maturity of an individual technology.

System Readiness Level (SRL)

• Component SRL: Individual component

• Composite SRL: Entire system or all components of a system integrated together.

What is the cost effectiveness equation?

CE = SE / (IC + SC)

• SE = system effectiveness

• IC = initial cost

• SC = sustainment cost

Agility Engineering

An approach that enables change in a timely cost-effective manner

• Agility Architectural Framework

• Agility Architectural Design

• Agility Metrics

Human Systems Integration

Approach that integrates technology, organizations, and people effectively.

• HSI considers systems in their operational context together with the necessary interactions between and among their human and technological elements to make them work in harmony and cost effectively from concept to retirement.

Interoperability Analysis

Approach that ensures the system interacts effectively with other systems.

• Capability for two or more systems to communicate with each other, exchange data and mutually use that information, data can be exchanged directly and satisfactorily.

Logistics Engineering

Approach that enables support for the entire life cycle

• Identification, acquisition, procurement. and provisioning of all support resources required to sustain operation and maintenance of a system.

Supportability Analysis

• Functional Failure Analysis

• Physical Failure Analysis

• Support modelling/simulation, recording and corrective action, deliverables/test/evaluations.

Manufacturability and Producibility Analysis

Approach that enables production in a responsible and cost-effective manner.

Reliability, availability, and maintainability engineering (RAM):

Approach that enables system to perform without failure, to be operational when needed, and to be retained in or restored to required function state.

• Used to influence both system and support system definitions.

• Used part of system verification.

Availability

The probability that a system, when under stated conditions, will operate satisfactorily at any point in time as required

Inherent Availability

Based on the inherent reliability and maintainability of the system.

Achieved Availability

Similar to inherent reliability, except preventative/scheduled maintenance is included.

Operational Availability

Assumes an actual operational environment and therefore includes logistics delay times and admin delay times.

Maintainability

The ability of a system to be repaired and restored to service when maintenance is conducted by personnel using specified skill levels and prescribed procedures and resources.

Corrective Maintenance

Unscheduled maintenance accomplished, as a result of failure, to restore a system to a specified level of performance.

Preventative Maintenance

Scheduled maintenance accomplished to retain a system at a specified level of performance.

Predictive Maintenance

Scheduled maintenance based on the in-service condition of a system to estimate when maintenance should be performed.

System Upgrade

Periodic maintenance to support system life extension and performance upgrades.

Mean Time to Repair (MTTR)

Mean time of the underlying probability distribution - includes times for failure detection, disassembly, active repair, reassembly, and activation.

Resilience Engineering

Approach that provides required capability when facing adversity

• Avoiding, withstanding, and recovery

Avoiding

Eliminate or reduce exposure to stress

Withstand

Resist capability degradation with stress

Recover

Replenish lost capability after degradation

Sustainability Engineering

An approach that supports the circular economy over its life.

• Considers environment and social aspects as key elements in product design to reduce the harmful impacts of the product throughout its life cycle.

System Safety Engineering

Reduces the likelihood of harm to people, assets, and the wider environment

Intrinsic Hazards

Caused by the material, or other design factors of the system elements in the system.

Functional Hazards

Result from incorrect, unexpected, or undesirable functions or performance of the system.

Socio-Technical Hazards

Result from interactions between the physical system and its operators and the wider environment.

Management/Cultural Hazards

Relate to the system and the wider management controls needed to realize and sustain the system.

System Security Engineering

Approach that identifies, protects from, detects, responds to, and recovers from anomalous and disruptive events, including those in a cyber contested environment.

• Focused on ensuring a system can function under anomalous and disruptive events by analyzing security threats and vulnerabilities to the system.

Loss-Driven Engineering (LDSE)

The value of adding unification of the QCs that address the potential losses associated with developing and using systems.

Modelling

The conception, creation, and refinement of models.

Analysis

Process of systematic, reproducible examination to gain insight.

Simulation

The process of using a model to predict and study the behavior or performance of the SOI for aspects represented in the model.

• Digital Model: Always a simulation

• Physical Model: Test

Physical Model

Represents aspects of a system with real parts

Digital Model

Can have many different expressions to represent, each of which may vary in degrees of formalism

Bidirectional Traceability

The ability to trace an object / entity / item to another object while automatically establishing a reverse link back to the initial object / entity / item.

Vertical Traceability

Most often referred to in context of organization levels or architectural levels of the system or product under development - parent/child relationships.

Horizontal Traceability

Involves traceability across the elements of a given level of the architectural or system structure across the life cycle.

Interface Management

Facilitate and manage the identification, definition, design, and management of interfaces across the system life cycle.

Architecture Description Framework

A set of conventions, principles, and practices for the architecture established within a specific domain of application or community of stakeholders.