Lecture 1.2: Systems Engineering and Architecting Definitions & Relationships

1. Lecture 1.2: Systems Engineering and Architecting Definitions & Relationships Dr. John MacCarthy UMBC CMSC 615 Fall, 2006

2. Systems Engineering and Biology: The Role of Structure and Function Definitions: System, System of Systems & Family of Systems Physical Architecture Hierarchy (Subsystems, Components and Subcomponent) Configuration Items (CIs) and Computer Software Configuration Items (CSCIs) Goals, Capabilities, Activities, Functions, and Methods Architectures (Informal and Formal) Systems Architecting & System Architects Systems Engineering & Systems Engineers Systems Engineering Process Relationship between Systems Engineering and System Architecting Relationship between Systems Engineers and System Architects Types of Engineering Systems Engineering is qualitatively different from other Engineering Fields Qualities of a Systems Engineer Career Prospects Agenda

3. Major SE Objective: Develop structures that perform required functions Major Systems Engineering Tasks: Identify needed System Functions Identify System Components (Structure) Allocate Functions to Components Develop Components Verify Components meet requirements (Test) Biology (Science) is inverse of SE process Major Bio Objective: Understand reason for and evolution of structures Major Bio Research Tasks: Start with System Identify Structures Test to identify Functions performed by Structures Test to understand functions Systems Engineering and Biology: The Role of Structure and Function

4. Definitions: A System is “an integrated composite of people, products, and processes that provide a capability to satisfy a stated need or objective.” – DoD SEMG A System is “an integrated set of elements that accomplish a defined objective. These elements include products (hardware, software, firmware), processes, people, information, techniques, facilities, services, and other support elements.” – INCOSE SE Handbook A System is “a set of components (subsystems, segments) acting together to achieve a set of common objectives via the accomplishment of a set of tasks.” - Buede A System is “a set of interacting components in which the behavior of each component affects the behavior of the whole set.” - Levis A System is “an interacting combination of elements viewed in relation to function.” – INCOSE A System is “any organized assembly of resources and procedures united and regulated by interaction or interdependence to accomplish a set of specific functions.” DoDAF Characteristics: Generally it performs all functions required to meet some (generally integrated) set of users’ objectives Generally there is a System Boundary (& interface(s)) that separates it from the External Systems (and Users) with which it interacts Generally it is composed of interacting Subsystems/ Components (CIs and/or CSCIs) Generally it can be HW, SW, HW & SW, facilities, or a combination Generally it is developed under a single contract Examples: Aircraft System, Ship System Weapon System, Sensor System, Weapon/Sensor System, Comm System, BMC2 System, etc. An integrated set of one or more Services Observations: No universal definition, but much in common Generally one person’s Subsystem is another person’s System Sometimes, in addition to (HW and/or SW) a system may include (or consist of) people (and/or organizations) and/or processes (a point of debate) Definitions of a “System” Exercise: Under what conditions would a Radar be considered System and under what conditions would it be considered a Subsystem/Component?

5. System of Systems: “A set or arrangement of independent systems that are related or connected to provide a given capability. The loss of any part of the system will degraded the performance or capabilities of the whole.” - DAG Characteristics: Examples: A Hospital or Clinic An IT Enterprise A Naval Battle Group An Aircraft Carrier Nuclear Waste Disposal SoS Family of Systems:“A set or arrangement of independent systems that can be arranged or interconnected in various ways to provide a different capabilities. The mix of systems can be tailored to proved desired capabilities, dependent on the situation.” - DAG Characteristics Examples: A group of Weapon and Sensor of a systems A group of Aircraft Legos Definitions of a “System of Systems”and “Family of Systems” Exercise: When does a “System” become a “System of Systems”? Under what conditions would an Aircraft Carrier be considered System of Systems and under what conditions would it be considered a System?

6. System of Systems: Battle Group Aircraft Carrier Aircraft Cruiser Destroyer Etc. System: Aircraft System Air Frame Propulsion Communications/Identification Navigation/Guidance Radar Flight Control Central Computer Electronic Warfare Weapon Delivery Equipment Armament Subsystem: Radar System Receiver Transmitter Antenna Radar Application SW Radar System SW Component: Radar Application SW Subcomponent (CSCI) 1 Subcomponent (CSCI) 2 Subcomponent (CSCI) 3 … Example of a System of Systems, System, Subsystems, and Components

7. Configuration Items (CIs) and Computer Software Configuration Items (CSCIs) • Configuration Item (CI): “an aggregation of hardware, firmware, or computer software, or any of their discreet portions, which satisfy an end-user function and is designed for separate configuration management. Any item required for logistic support and designated for separate procurement is generally identified as a CI. Components can be designated as CIs because of crucial interfaces or need to be integrated with operational or other components within or outside of the system.” • Computer Software Configuration Item (CSCI): an aggregation of software, software components and/or classes that is designated as a CI. In UML they are often denoted as “Packages.” Note: CIs are identified and controlled through Configuration Management. Note: All CIs should be reflected in the WBS as a WBS element.

8. Formal Physical Architecture Hierarchy(INCOSE SE Handbook) • System: An integrated set of elements, segments and/or subsystems that accomplish a defined objective, such as an air transportation system. • Element or Segment: A major product, service, or facility of the system, e.g., the aircraft element of an air transportation system (commonly used, but subsystems can be used instead of element/segments). • Subsystem: An integrated set of assemblies, components, and parts which performs a cleanly and clearly separated function, involving similar technical skills, or a separate supplier. Examples are an aircraft on-board communications subsystem or an airport control tower as a subsystem of the air transportation system. • Assembly: An integrated set of components and/or subassemblies that comprise a defined part of a subsystem, e.g., the pilot’s radar display console or the fuel injection assembly of the aircraft propulsion subsystem. • Subassembly: An integrated set of components and/or parts that comprise a well-defined portion of an assembly, e.g., a video display with its related integrated circuitry or a pilot’s radio headset. • Component: Comprised of multiple parts; a cleanly identified item, e.g., a cathode ray tube or the ear-piece of the pilot’s radio headset. • Part: The lowest level of separately identifiable items, e.g., a bolt to hold a console in place. Note that for large projects Software Developers generally decompose SW along similar lines.

9. Informal Physical/SW Architecture Hierarchy • Software often uses similar notations • In OOD/UML Classes are often assigned to (aggregated into) hierarchies of “Packages” that may be so characterized. • For the Purposes of this course, I will use the terms: • “External System” to mean a collection of HW/SW that interfaces with the “System”, is perceived by the “System” as a single unit, and was not developed under the current contract (and possibly by one or more other contractors and/or agencies). • “System” to mean a collection of HW/SW that is being developed under a single contract. • “Subsystem” to mean an aggregate of components that make up a portion of a System • “Component” to mean a CI or CSCI • “Subcomponent” to mean one of a collection of different items that make up a CI or CSCI

10. Definitions: Goals or Objectives are generally high-level statements identifying what the user wants the system to do (e.g., defend friendly forces from enemy attack) An Activity (or Task) is generally something that must be performed (by an organization, person, HW/SW System and/or HW or SW Component) to achieve a specific goal (objective) or accomplish a specific higher-level Activity. A Function is generally understood to be an Activity performed by a HW/SW system, subsystem, element, subelement, component, subcomponent, etc. (as opposed to activities performed by people and/or organizations). A Method is generally understood to be an Function (allocated to and) performed by a SW Class or Object Observations: Goals/Objectives may be decomposed into Activities/ Functions Activities/Functions may be further decomposed into sub-activities/ sub-functions (functional decomposition) Within the context of Systems Engineering, the term “Function” has a much broader meaning than in Software Development. Goals, Activities, Functions, and Methods

11. Architectures: Informal [1] • Types of Architectures: • Functional Architectures • Physical/Component/SW Architectures • Data/Data Flow Architectures • Allocated (Functions to Components) • Architectures & Architecture Standards: • IDEF • DoD Architecture Framework (DoDAF) • Operational Views • Systems Views • Technical Standards View • Zackmann Framework • Service Oriented Architectures (SOA) • Model-Driven Architectures (MDA) • Other

12. Architectures: Formal [2] • Definitions: • Architecture is “the structure – in terms of components, connections, and constraints – of product, process, or element.” – Rechtin • Architecture is “the structure of components, their relationships, and the principals and guidelines governing their design and evolution over time.” – DoDAF • An Architecture Description is “a representation of a defined domain, as part of a current or future point in time, in terms of its component parts, what those parts do, how the parts relate to each other and the rules and constraints under which the parts function.” “The term architecture will be used as a shorthand reference to architecture.” The Operational View, System View and Technical Standards view together constitute an architecture description.- DoDAF • Architecture View is “ • System Architecture is “the arrangement of elements and subsystems and the allocation of functions to them to meet system requirements.” – DSMC SEF & INCOSE SEF

13. Functional Architecture: “identifies and structures the allocated functional and performance requirements” – SEF a “logical architecture that defines what a system must do, a decomposition of the system’s top-level function” – Buede a “logical model that captures the transformation of inputs into outputs using control information” - Buede The hierarchical arrangement of functions, their internal and external (external to the aggregation itself) functional interfaces and external physical interfaces, their respective functional and performance requirements, and the design constraints. – INCOSE SEH Physical Architecture: “depicts the system product by showing how it is broken down into subsystems and components.” – SEF identifies the “resources for every function identified in the functional architecture.” – Buede “The hierarchical arrangement of product and process solutions, their functional and performance requirements; their internal and external (external to the aggregation itself) functional and physical interfaces and requirements, and the physical constraints that form the basis of design requirements. The physical architecture provides the basis for system/CI baselines as a function of the acquisition phase. It documents one or more physical designs as required to 1) accomplish effectiveness analysis, risk analysis, and technology transition planning; 2) establish the feasibility of physically realizing the functional architecture; 3) identify manufacturing verification, support and training requirements; 4) document the configuration of prototypes and other test articles, and 5) define in increasing detail the solution to identified needs.” – INCOSE SEH Functional and Physical Architectures [3]

14. DoDAF Definitions: Operational View: “describes the tasks and activities necessary to perform a a mission, the participating nodes, and the associated information exchanges.” “A pure OV is material independent.” - DODAF System View: “describes the systems of concern and the connections among those systems in the context of the OV.” - DODAF Technical Standards View: “describes a profile of the minimal set of time-phased standards and rules governing the implementation, arrangement, interaction, and interdependence of systems.” - DODAF Observations Architecture has many (not necessarily consistent) meanings A System Architecture presupposes Functional Architecture Physical Architecture For Systems Engineers, Software Architecture is considered part of the “Physical” Architecture Functional Architecture is what the system has to do Physical Architecture is the components that will do it As such the complete System Architecture describes not just what the system consists of and how it is connected, but also what the system must do and how it will do it DoD Architecture Framework [4]

15. Systems Architecting and Systems Architects • Systems Architecting: Developing a System Architecture • Systems Architect: One who develops System Architectures • Types of (System) Architects: • System of Systems Architect: responsible for establishing the architecture for a System of Systems (generally a systems engineer), generally orchestrates the work of System Architects • System Architect: responsible for establishing the architecture for a System (generally a systems engineer), generally orchestrates the work of “Specialty Architects” • Enterprise Architects: responsible for establishing the architecture for an Enterprise (generally an IT or communications systems engineer), generally orchestrates the work of “Specialty Architects” • Domain Architect: responsible for establishing the domain architecture (generally a systems engineer/analyst) • Business/Process Architect: responsible for establishing the architecture for a process (generally a systems analyst) • Software Architect: responsible for establishing the software (logical and component) architecture for a system (generally a software (design) engineer) • Data Architect: responsible for establishing the data architecture for a system (generally a data engineer) • Communications Architect: responsible for establishing the communications (network) architecture for a system (generally a communications (design) engineer) • Hardware/Facility Architect: responsible for establishing the hardware/facility architecture for a system, generally a design engineer (e.g., EE, Mechanical, Nuclear, Civil, etc.) • Transportation Architect: responsible for establishing the transportation architecture for a system, generally a transportation engineer Note that what is meant by a “System Architect” depends on what one views as the “System.”

16. Systems Engineering • Definitions: • Systems Engineering consists of “the technical knowledge domain and the systems engineering management domain” – DSMC SEF • Systems Engineering is “an interdisciplinary approach and means to enable the realization of successful systems. Systems engineering: a.) encompasses the scientific and engineering efforts related to the development, manufacturing, verification, deployment, operations, support, and disposal of system products and processes; b.) develops needed user training equipments, procedures, and data; c.) establishes and maintains configuration management of the system; d.) develops work breakdown structures and statements of work; and e.) provides information for management decision making.” – INCOSE SE Handbook • Systems Engineering is a “logical sequence of activities and decisions that transforms an operational need into a description of system performance parameters and a preferred system configuration.” - MIL-STD-499A • Systems Engineering is an “interdisciplinary approach that encompasses the entire technical effort, and evolves into and verifies an integrated and life cycle balanced set of system people, products, and process solutions that satisfy customer needs.” - EIA Standard IS-632 • Systems Engineering is an “interdisciplinary approach, collaborative approach that derives, evolves, and verifies a life-cycle balanced system solution which satisfies customer expectations and meets public acceptability.” - IEEE P1220 • Systems Engineering Process is “a predefined set of activities selectively used to accomplish Systems Engineering tasks.” It is “a comprehensive, iterative problem solving process that is used to: a.) transform validated customer needs and requirements into a life-cycle balanced solution set of system product and process designs, b.) generate information for decision makers, and c.) provide information for the next acquisition phase. The problem and success criteria are defined through requirements analysis, functional analysis/allocation, and systems analysis and control.” – INCOSE SHE • Observations: • Systems Engineering is a process for achieving a program’s technical objectives • The (Lead/Chief) Systems Engineer is responsible for establishing, monitoring, and guiding (i.e., managing) this process

17. Some Systems Engineering “Standards” • DSMC Systems Engineering Fundamentals (SEF) • INCOSE Systems Engineering Handbook (SEH) • NASA Systems Engineering Handbook • IEEE–1220-2005: Standard for Application and Management of the Systems Engineering Process • EIA/IS-632 • ISO/IEC 15288 • MIL-STD-499 • MIL-HDBK-881 • MIL-STD-1521B

18. Systems Engineers • Systems Engineer • A Systems Engineer is “an engineer trained or experienced in the field of Systems Engineering.” –SEF • Types of Systems Engineers • Systems Engineering Managers • Systems Architects (Domain, HW, SW, Comm, Process, etc.) • Systems Engineers (Domain, HW, SW, Comm, Process, etc.) • Requirements Engineers • Requirements Analysts • Systems Analysts • Systems Modelers • Test Systems Engineers • “Specialty” Engineers • Life Cycle Costing • Risk Management • Configuration Management • Reliability, Availability, Maintainability • Information Assurance • Security • Safety • Human Factors • Integrated Logistic Support • …

19. SE Handbook SE Process

20. SEF Systems Engineering Process

21. Chief Systems Engineer: Primarily concerned with ensuring that the Systems Engineering Process is defined and followed Responsible for ensuring that the product meets customer requirements: Architecture Requirements Analysis Design Development Test Configuration Management Risk Management … Chief Systems Architect: Primarily concerned with developing the Architecture Responsible for ensuring the Architecture meets customer requirements The Architecture is implementable Comparing Systems Engineers and Systems Architects Systems Architecting is a Systems Engineering subspecialty

22. Conclusions on Definitions • There is no single “correct” definition for any of these terms (every reference has its own slightly different definition) • There are common themes to each set of definitions for a given term. • The terms are fuzzy but well-defined