11 Physical Elements
Figure 91 gives an overview of the physical elements and their relationships. These are based on the Technology Layer.
Note: This figure does not show all permitted relationships: every element in the language can have composition, aggregation, and specialization relationships with elements of the same type; furthermore, there are indirect relationships that can be derived as explained in Section 5.6.
The equipment element is the main active structure element within the physical elements. This element is used to model structural entities in this layer. It is used to model any physical machinery, tools, instruments, or implements. It strictly models the structural aspect of a system; its behavior is modeled by an explicit relationship to the behavior elements.
The inter-relationships of physical elements are mainly formed by the logistics infrastructure. The path element from the Technology Layer models the relation between two or more nodes, through which these nodes can exchange information or material. The physical realization of a path is modeled with a distribution network; i.e., a physical connection between two or more pieces of equipment (or other physical networks). This can be used to model, for example, rail or road networks, the water supply, power grid, or gas network.
Equipment comprises all active processing elements that carry out physical processes in which materials (which are a special kind of technology object) are used or transformed. Equipment is a specialization of the node element from the Technology Layer. Therefore, it is possible to model nodes that are formed by a combination of IT infrastructure (devices, system software) and physical infrastructure (equipment); e.g., an MRI scanner at a hospital, a production plant with its control systems, etc.
Material can be accessed (e.g., created, used, stored, moved, or transformed) by equipment. Equipment can serve other equipment, and also other active structure elements such as business roles and actors, and facilities can be assigned to equipment. A piece of equipment can be composed of other pieces of equipment. Equipment can be assigned to (i.e., installed and used in or on) a facility and can be aggregated in a location.
The name of a piece of equipment should preferably be a noun.
A useful specialization of equipment is vehicle, for describing, for example, trucks, cars, trains, ships, and airplanes.
A facility is a specialization of a node. It represents a physical resource that has the capability of facilitating (e.g., housing or locating) the use of equipment. It is typically used to model factories, buildings, or outdoor constructions that have an important role in production or distribution processes. Examples of facilities include a factory, a laboratory, a warehouse, a shopping mall, a cave, or a spaceship. Facilities may be composite; i.e., consist of sub-facilities.
Facilities can be interconnected by distribution networks. Material can be accessed (e.g., created, used, stored, moved, or transformed) by equipment. A facility can serve other facilities, and also other active structure elements such as business roles and actors, and locations can be assigned to facilities. A facility can be composed of other facilities and can be aggregated in a location.
The name of a facility should preferably be a noun referring to the type of facility; e.g., “Rotterdam harbor oil refinery”.
A distribution network represents the physical distribution or transportation infrastructure. It embodies the physical realization of the logical paths between nodes.
A distribution network connects two or more nodes. A distribution network may realize one or more paths. A distribution network can consist of sub-networks and can aggregate facilities and equipment, for example, to model railway stations and trains that are part of a rail network.
No separate physical behavior elements are defined. Rather, the behavior elements from the Technology Layer (technology function, process, interaction, service, and event) are used to model the behavior of all nodes, including physical equipment. Since equipment will very often be computer-controlled or in other ways have a close relationship to IT (also think of sensors, Internet of Things), their behavior can be described in an integral way using the existing technology behavior concepts.
Material represents tangible physical matter, with attributes such as size and weight. It is typically used to model raw materials and physical products, and also energy sources such as fuel. Material can be accessed by physical processes.
The name of material should be a noun. Pieces of material may be composed of other pieces of material.
An Assembly Line, modeled as equipment, and installed at a facility Manufacturing Plant, makes use of materials Pre-Assembled Circuit Board, Internal Antenna, and Plastic Case to produce material Vehicle Telematics Appliance. The appliance, initially located at the Manufacturing Plant facility, is subsequently transported to the facilities National Distribution Center and Local Distribution Center, making use of the distribution networks Overseas Shipping and Local Trucking. These distribution networks together realize the path Intermodal Freight.
Table 9 gives an overview of the physical elements, with their definitions.
Table 9: Physical Elements
One or more physical machines, tools, or instruments that can create, use, store, move, or transform materials.
a physical structure or environment.
A physical network used to transport materials or energy.
Tangible physical matter or physical elements.