Process engineering refers to engineering which is collaborative and concerned with completing a project as a whole.

Semiconductor devices

In the electronics industry, especially for those building ICs, some technologists can be referred to as "process engineers" as contrasted to "design engineers". The project would be collaborative; the process engineers might be considered responsible for realizing a physical circuit design which might have been laid out and simulated by the design engineers. Thus the process engineers would specialize in the materials and processes of semiconductor fabrication.

Chemical engineering

A chemical process is a series of unit operations used to produce a material in large quantities.

In the chemical industry, chemical engineers will use the following to define or illustrate a process:

• Process Flow Diagram (PFD)
• Piping and Instrumentation Diagram (P&ID)
• Simplified Process Description
• Detailed Process Description
• Project management

Systems engineering (SE)

CPRET - A Process Definition according to AFIS (Association Française d'Ingénierie Système) dedicated to SE and open to all domains.

Processes

The System Engineering normative documents and those related to the Maturity Models are based on processes. For example, System Engineering processes of the EIA-632 and processes involved in a CMMI institutionalization and improvement approach.

Processes are generally defined as "a set of interdependent tasks transforming input elements into products". ^[1]

In practice, constraints imposed on the tasks and resources required to implement them are essential for executing the tasks mentioned and then, are involved in their definition (example of the so-called technological constraints).

CPRET definition of processes

The complete definition of a process must include the Constraints, Products, Resources, input Elements and Transformations, leading to the CPRET acronym to be used as name and mnemonic of the selected definition.

CPRET representation of a process

The CPRET representation integrates the process Mission and Environment in order to offer an external standpoint.

CPRET definition modelling

Several models may correspond to a single definition depending on the language used (UML or another language).

Note: process definition and modelling are interdependent notions but different the one from the other.

CPRET terminology

The following components and terms apply to the CPRET definition of processes.

• Process
  • A process is a set of transformations of input elements into products: respecting constraints,
  • requiring resources,
  • meeting a defined mission, corresponding to a specific purpose adapted to a given environment.
• Environment
  • Natural conditions and external factors impacting a

process.

• Mission
  • Purpose of the process tailored to a given environment.
• Constraints
  • Imposed conditions, rules or regulations.
• Products
  • All what is generated by transformations. The products

can be of the desired or not desired type (e.g., the software system and bugs, the refined products and waste).

• Resources
  • Human resources, energy, time and other means required

to carry out the transformations.

• Elements as inputs
  • Elements submitted to transformations for producing the

products.

• Transformations
  • Operations organized according to a logic aimed at optimizing the attainment of specific products from the input elements, with the allocated resources and on compliance with the imposed constraints.

CPRET through examples

The purpose of the following examples is to illustrate the definitions with concrete cases. These examples come from the Engineering field but also from other fields to show that the CPRET definition of processes is not limited to the System Engineering context.

Examples of processes

• An engineering (EIA-632, ISO 15288, etc.)
• A concert
• A polling campaign
• A certification

Examples of environment

• Various levels of maturity, technicality, equipment
• An audience
• A political system
• Practices

Examples of mission

• Supply better quality products
• Satisfy the public, critics
• Have candidates elected
• Obtain the desired approval

Examples of constraints

• Imposed technologies
• Correct acoustics
• Speaking times
• A reference model (ISO, CMMI, etc.)

Examples of products

• A mobile telephone network
• A show
• Vote results
• A quality label

Examples of resources

• Development teams
• An orchestra and its instruments
• An organization
• An assessment team

Examples of elements as inputs

• Specifications
• Scores
• Candidates
• A company and its practices

Examples of transformations

• Define an architecture
• Play the scores
• Make people vote for a candidate
• Audit the organization

Conclusions

Sharing a formalized definition of processes, whatever the definition, means speaking the same language. The CPRET formalized definition systematically addresses the input Elements, Transformations and Products but also the other essential components of a Process, namely the Constraints and Resources. Among the resources, note the specificity of the Resource-Time component which passes inexorably and irreversibly, with problems of synchronization and sequencing.

This definition states that environment is an external factor which cannot be avoided: as a matter of fact, a process is always interdependent with other phenomena including other processes.