Systems Engineering

SYSTEMS ENGINEERING

“System” from the Greek word systema, meaning “organized whole”

• a regularly interacting or interdependent group of items forming a unified whole

• a composite of equipment, skills, and techniques capable of performing and/or supporting an operational role.

• a construct or collection of different elements that together produce results not obtainable by the element alone

WHAT IS A SYSTEM?

Elements of a system

1. Components – are the operating parts of a system consisting of input, process, and output.

2. Attributes – are the properties or discernable manifestations of the components of the system.

3. Relationships – are the links between components and attributes.

PROPERTIES OF THE SET OF COMPONENTS1. The properties and behavior of each

component of the set has an effect on the properties and behavior of the whole set.

2. The properties and behavior of each component of the set depends on the properties and behavior of at least one other component in the set.

3. Each possible subsets of components has the two properties listed previously; the components cannot be divided into independent subsets.

The purposeful action performed by a system is its FUNCTION.

- a common system function is that of altering material, energy, or information.

- this alteration embraces input, output, and process Systems that alter material, energy, or information are composed ofa. structural components – static partsb. operating components – parts that perform the processingc. flow components - the material, energy, or information being altered

Structural, operating, and flow components have various attributes that affect their influence on the system.

ex. attributes of electrical system may be described in terms of inductance, capacitance, impedance, and so on.

A system, condition, situation, or state is set forth to describe a set of components, attributes, and relations

RELATIONAL VIEW (AS OPPOSED TO SYSTEM VIEW )• Relations exist between component pairs

(though many pairs may share relations) • Relation is formed from the imminent

qualities of the components (e.g. their essential characteristics) System is in physical, temporal and spatial arrangement of components

• Relations imply direct interactions . Systems are defined by the common reference to the entire set of components

RELATIONAL VIEW (AS OPPOSED TO SYSTEM VIEW ) Relationship orders:

• First order: functionally necessary – symbiosis

• Second Order: Synergistic (relationship adds to the system performance)

• Redundancy replication for purpose of system continuation

GENERAL CHARACTERISTICS OF A SYSTEM

1.a system constitutes a complex combination of resources in the form of human beings, materials, equipments, software, facilities, data, money

2.a system is contained within some form of hierarchy

3.a system maybe broken down into subsystems and related components

4.a system must have a purpose

System and Subsystem

If two hierarchical levels are involved in a given system, the lower is conveniently called a subsystem.

The definition of the system is not complete without consideration for its position in the hierarchy of systems.

Every system is made up of components, and any component can be broken down into smaller components.


COMPONENTS: Equipment items, people, and information

Example:

SYSTEM: Air Transportation

SUBSYSTEM: Aircraft, terminal, ground support equipment, and controls


• Material, energy, and/or information must open pass through the boundaries as input to the system.

It is important to define the system under consideration by specifying its limits, boundaries, or scope.• Environment – everything that remains outside the boundaries of the system. No system is completely isolated from its environment.

• Throughput - that which enters the system in one form and leaves the system in another form.


Total System – consists of all components, attributes, and relationships needed to accomplish an objective.

Constraints – limits the operation and define the boundary within which it is intended to operate.

CLASIFICATION OF SYSTEMS

1. Natural and Human-made systems

2. Physical and Conceptual systems

3. Static and Dynamic systems

4. Closed and Open systems

CLASSIFICATION OF SYSTEMS

1. Natural Systems – those that came into being through natural processes. They exhibit a high degree of order and equilibrium.2. Human-made Systems – those in which human beings have intervened through components, attributes, or relationships.

3. Physical Systems – those that manifest themselves in physical form and composed of real components; these consumes a physical space.


4. Conceptual Systems – symbols represent the attribute of components; e.g., ideas, plans, concepts, and hypothesis. These are organization of ideas.• The totality of elements encompassed by all components, attributes, and relationships focused on a given result employ a process in the guiding state of a system. A process may be:

a. Mental (thinking, planning, learning)

b. Mental-Motor (writing, drawing, testing)

c. Mechanical (operating, functioning, producing)


5. Static System – one having structure without activity (e.g. bridge)

6. Dynamic System – combines structural components with activity (e.g. school)

7. Closed System – one that does not interact significantly with its environment and exhibits the characteristic of equilibrium resulting from internal rigidity that maintains the system in spite of influences from the environment. 8. Open System – allows information, energy, and matter to cross its boundaries. It interacts with the environment and exhibits the characteristics of steady state that made them self-regulatory and self-adaptive (plants, ecological system, business organization)


Both closed and open system exhibits the property of entropy.

Entropy – defined as the degree of disorganization

CHALLENGES OF AN EXISTING SYSTEM1.constantly changing requirements2.more emphasis on systems3.increasing system complexities4.extended system life-cycles – shorter

technology life cycles5.greater utilization of commercial off- the-

shelf products6.increasing globalization7.greater international competition8.more outsourcing9.eroding industrial base10.higher overall life-cycle costs

Systems Engineering is an interdisciplinary approach and means to enable the realization of successful systems.

It focuses on defining customer needs and required functionality early in the development cycle, documenting requirements, then proceeding with design synthesis and system validation while considering the complete problem:

Operations

Performance

Tests

Manufacturing

Cost & Schedule

Training & Supports

Disposal

WHAT IS SYSTEMS ENGINEERING?

Systems Engineering integrates all of the disciplines and specialty groups into a team effort forming a structured development process that proceeds from concept to production to operation.

Systems Engineering considers both the business and the technical needs of all customers with the goal of providing a quality product that meets the user needs

WHAT IS SYSTEMS ENGINEERING?

Systems engineering is a management technology.

Technology is the organization, application,

and delivery of scientific and other forms of knowledge for the betterment of a client group. This is a functional definition of technology as a fundamentally human activity. A technology inherently involves a purposeful human extension of one or more natural processes.

SYSTEMS ENGINEERING AS A MANAGEMENT TECHNOLOGY

Management involves the interaction of the organization with the environment. A purposeof management is to enable organizations to better cope with their environments soas to achieve purposeful goals and objectives.

SYSTEMS ENGINEERING AS A MANAGEMENT TECHNOLOGY

System Engineering process shall:

1.Transform approved operational needs and

requirements into an integrated system design solution through concurrent consideration of all life-cycle needs (development, manufacturing, test and evaluation, deployment, operations, support, training, and disposal)

2.Ensure the operability and integration of all operational, functional, and physical interfaces. Ensure that system definition and design reflect the requirements for all system elements (hardware, software, facilities, people, and data)

3.Characterize and manage technical risks

SYSTEM LIFE CYCLE ENGINEERING

A.THE PRODUCT AND THE SYSTEM LIFE CYCLE

SYSTEM LIFE CYCLE ENGINEERINGA.THE PRODUCT AND THE SYSTEM LIFE

CYCLE

THE ENGINEERED SYSTEM

CHARACTERISTICS OF AN ENGINEERED SYSTEM

1.Engineered system have a functional purpose in response to an identified need and have the ability to achieve some stated operational objective.

2.Engineered systems are brought into being and operate over a life cycle, beginning with a need and ending with phase out and disposal.


3.Engineered systems are composed of a combination of resources, such as humans, information, software, materials, equipment, facilities and money.

4.Engineered systems are composed of subsystems and related components that interact with each other to produce the system response or behavior.


5.Engineered system are part of hierarchy and are influenced by external factors from larger systems of which they are part.

6.Engineered systems are embedded into the natural world and interact with it in desirable as well as undesorable ways.

ENGINEERING THE SYSTEM AND THE PRODUCT

Engineering the system and the product requires an interdisciplinary approach embracing both the product and associated capabilities for production or construction, product and production system maintenance, and the phase out and disposal.

The cost effectiveness of the engineered system and the product can be enhanced by placing emphasis on the following:

1. Improving methods for defining product and system requirements as they relate to true customer needs. This should be done early in the design phase, along with determination of performance, effectiveness, and the essential system characteristics.


2. Addressing the total system with all of its elements from a life-cycle perspective, and from the product or prime equipment to its elements of support. This means defining the system in functional terms before identifying hardware, software, people, facilities, information, or combination thereof.


3. Considering the overall system hierarchy and interactions between various levels in the hierarchy. This includes intra-relationships among system elements and interrelationships between higher and lower levels within the system.


4. Organizing and integrating the necessary engineering and related disciplines into the main system-engineering effort in a timely concurrent manner.


5. Establishing a disciplined approach with appropriate review, evaluation, and feedback provisions to insure orderly and efficient progress from the initial identification of need through phase-out and disposal.

SYSTEM LIFE CYCLE ENGINEERING

CONCURRENT LIFE CYCLE

B.DESIGNING FOR THE LIFE CYCLEIt should:1.Transform a need into a product/system

configuration2.Ensure the design’s compatibility with

related physical and functional requirements

3.Consider operational outcomes expressed as:a. producibility e. supportabilityb. reliability f. serviceabilityc. maintainability g. disposabilityd. usability

Technological activities and interactions within the system life-cycle process.

SYSTEM ENGINEERING PROCESSLIFE CYCLE PROCESS PHASES AND STEPS

SYSTEM ENGINEERING PROCESSOTHER SYSTEMS ENGINEERING PROCESS MODELS

SYSTEM ENGINEERING PROCESSOTHER SYSTEMS ENGINEERING PROCESS MODELS

SYSTEM DESIGN CONSIDERATIONS

SYSTEM ENGINEERING CONSIDERATIONSDEVELOPMENT OF DESIGN CRITERIA

SYSTEM ENGINEERING CONSIDERATIONS

DEVELOPMENT OF DESIGN CRITERIA MUST BE BASED ON:

1. Design considerations – the full range of attributes and characteristics that could be exhibited by an engineered system, product, or structure. (figure 2.6)

2. Design-dependent parameters (DDPs) – attributes and/or characteristics inherent in the design to be predicted or estimated (ex. Weight, design life, reliability, producibility, maintainability, and pollutability)



3. Design-independent parameters (DIPs) – factors internal to the design that must be estimated and forecasted for use in design evaluation (ex. Fuel cost/dollar, interest rate, labor rates, and material cost/dollar)

4. Technical performance measures (TPMs) – predicted and/or estimated values for design-dependent parameters. They include values for higher level (derived) considerations (ex. Availability cost, flexibility, and supportability)



5. Design criteria – customer specified or negotiated target values for technical performance measures.


CONSIDERING MULTIPLE CRITERIAMOE – MEASURES OF EFFECTIVENESS1. System size and weight2. Range and accuracy3. Speed of performance4. Capacity5. Operational availability6. Reliability7. Maintainability8. Supportability9. cost

CONSIDERING MULTIPLE CRITERIA

SYSTEM SYNTHESIS, ANALYSIS AND EVALUATION

• Synthesis. Customer requirement for the project is synthesized. It is the creative process of putting known things together into new and more useful combinations

• Analysis. It involves the functions of estimation and prediction of design dependent parameter (DDP) values (TPMs) and the forecasting of design independent (DIP) values from information found in physical and economic databases

• Evaluation. Evaluation of design against other design and check for compliance with customer requirements

System Engineering Morphology for Product Realization

Block 1. customerBlock 2. functional termsBlock 3. design team supported by

traditional and computer-based tools for design synthesis (block 4)

Block 4. traditional and computer-based tools

Block 5. top down and bottom up activities

Block 6. design dependent parameter (DDP) values (TPM) and the forecasting of design independent (DIP) values from information found in physical and economic databases (block 7)

Block 7. physical and economic databases

Block 8. evaluation of each design candidate

Block 9. decision

DISCUSSION OF THE TEN-BLOCK MORPHOLOGY

A. The technologies (Block 0)• technologies are the product of applied

research• evolve from the activities of engineering

research and development• it is the most potent ingredient for

advancing the capabilities of systems, products and structures


A. The technologies (Block 0)• designer/producer help the customer

undertand what might be for each technological choice

• designer/producer must be able to articulate and deliver appropriate technologial solutions on time and within budget to attain and retain a competitive edge in the global market place.


B.The customer (Block 1)• the purpose is to sarisfy the customer

(and stakeholder) needs and expectations.

• functions must be provided and all requirements from the perspective of the customer or the customer’s representative be satisfied during the design process

• stakeholder and any other special interest should be included in the “voice of the customer” in a way that reflects all needs and concerns

• includes ecological and human impacts


C.Need, functions and requirements (Block 2)

• to gather and specify the behavior of the product or system in functional terms

• market study identifies a need, an opportunity or a deficiency

• from the need comes a definition of the basic requirements in functional terms

• the product or system should be idnetified by its function, not its form


D.The design team (Block 3)• Should be organized to incorporate in-

depth technical expertise• Included must be expertise in each of

the product life-cycle phases and elements contained within the set of system requirements

• Intended purpose must be satisfied, followed by producibility, reliability, maintainability, disposability, environment compliance and others


D.Design synthesis (Block 4)• It is a creative activity that relies on the

knowledge of experts about the state of the art as well as the state of technology

STEPS1.a number of feasible design alternatives

are fashioned and presented for analysis2.the candidate design is driven by both a

top-down functional decomposition and a bottom-up combinatorial approach utilizing available system elements through block 5


D.Design synthesis (Block 4)STEPS

3.arrow E represents a blending of these approaches

4.define each alternative to allow for life-cycle analysis in view of the requirements

5.arrow F highlights this definition process as it pertains to the passing of candidate design alternatives to design analysis in block 6


E.Top down and bottom up (Block 5)• it is iterative with the number of

iterations determined by the creativity and skill of the design team

• starts with requirements for the external behavior of any component of the system up to its decomposition


F.Estimation and prediction (Block 6)• generation of cost and effectiveness

measures• uses models and database information to

obtain DDP values of (TPMs) for each design alternative. Models and simulations are based on physical laws, assumptions and empirical data


G.Physical and economic databases (Block 7)

• provides a resource for the design process, rather than being an actual step in the process flow

• DIP values are determined and provided to the activity of design evaluation

• it includes descriptions of existing system components, parts, and subsystems


H.Design evaluation (Block 8)It should be embedded

appropriately within the process and then pursued continuously as product design and development progresses.

I. Design decision (Block 9)

IMPLEMENTING SYSTEMS ENGINEERING

APPLICATION DOMAINS FOR SYSTEMS ENGINEERING

1.Large scale systems with many components, such as a space-based system, an urban transportation system, or a hydroelectric power-generating system.

2.Small sclae systems with relatively few components such as a local area communications system, a computer system, a hydraulic system, or a mechanical braking system.



3.Manufacturing or production systems where there are input-output relationships, processes, processors, control software, facilities and people.

4.Systems where a great deal of new design and development effort is required (ex. introduction of advanced technologies).



5.Systems where the design is based largely on the use of existing COTS equipment, commercial software, or existing facilities.

6.Systems that are highly equipment, software, facilities or data intensive.



7.Systems where there are several suppliers involved in the design and development process at the national and possibly international level.

8.Systems being designed and developed for use in the defense, civilian, commercial, or private sectors separately or jointly.

APPLICATION AREAS FOR SYSTEMS ENGINEERING

RECOGNIZING AND MANAGING LIFE CYCLE IMPACTS

POTENTIAL BENEFITS FROM SYSTEMS ENGINEERING

POTENTIAL BENEFITS FROM SYSTEMS ENGINEERING

1. Reduction in the cost of the system design and development, production and/or construction, system operation and support, system retirement and material disposal (reduction in the life cycle cost)

2. Reduction in system acquisition time (or time from the initial identification of a customer need to the delivery of a system to the customer).

3. More visibility and a reduction in the risks associated with the design decision making process. Increased visibility is provided through viewing the system from a long-term and life-cycle perspective.

Documents

Systems Engineering