The object information can express experts’ knowledge about requirements for a specific object in the offshore plant topside such as a module, equipment, and so on.
If an expert possesses the knowledge that “the separator should be arranged along the longitudinal direction of the offshore plant,” it can be represented as one objective information. The keywords in the knowledge are the target object (e.g.,
“separator”), the attribute (e.g., “orientation”), and the target value (e.g., “1_EXT”).
Adding an ID (e.g., “E001”) to each distinct rule, one object information can be represented with four properties: the ID, target object, attribute, and target value.
Here, the target value is used to give a certain value to the object. Again, the target value can be defined with three sub-key words: standard value (e.g., “1”), boundary type (e.g., “EXT” for exact), and unit type (e.g., none for this example). An example of object information is shown in Figure 3-2. The set of object information for all the objects defined in the domain is called an object list in this study.
Figure 3-2 Configuration of the object information
To use four properties (ID, target object, attribute, and target value) in the AEM, they have to be specified by a suitable data type for them, as shown in Table 3-1.
The ID and target object can be expressed by a string type to distinct the target object for the object information. The attribute represents properties of the target object, and it can be certain words like “Order”, “Orientation”, “COG.x”, “COG.y”,
“COG.z”, “Volume”, “Area”, and so on. Using an enumerator composed of those kinds of words, we can express the attribute. The description of attributes of the
object information is listed in Table 3-2. And the target value can be expressed by a new type which is called metric type. In this study, the metric type is used to represent the target value for the object information and the relation information.
As mentioned earlier, the metric type is composed of three sub-key words;
standard value, boundary type, and unit type. The standard value is used to specify a certain value for the target value, and it can be expressed by double or integer of data type.
The boundary type represents the limit of the target value, and it can be certain words like “EXT” for exact value, “MAX” for maximum value, “MIN” for minimum value, and “PRO” for proposed value. Using an enumerator composed of those kinds of words, we can express the boundary type.
The unit type is a unit of the standard value. And it also can be expressed by using an enumerator. In this study, SI unit is used, thus m, m2, m3 and so on are included in the unit type. Of course, for a specific target value having no dimension, the unit can be none. The data type and properties of the target value according to the attributes are listed in
Table 3-3. By using the metric type, various knowledge can be defined.
For example, if one object information has specific metric type (“1_EXT”) for the attribute (“Orientation”), it means the target object must have exact orientation along the longitudinal direction of the offshore plant. As with the above, the various criteria about one object’s requirements such as the order (means location), orientation, COG position, and so on can be represented using the metric type.
Table 3-1 Properties of the object information
Properties Data type Description
ID String ID
Target
object String Module, deck, equipment, passage Attribute Enumerator
type
Properties of the target object: Order (means location), Orientation, COG.x, COG.y, COG.z, Volume, Area, … Target
value Metric type
Designated value of the property of the target object - Standard value: certain value for the target value
- Boundary type: EXT (exact), MAX (maximum), MIN (minimum), PRO (proposed)
- Unit type: unit of the target value (none, m, m2, m3, …)
Table 3-2 Description of attributes of the object information
Attributes Description
Order Designated order for the object’s location (generally, for modules) Orientation Binary value representing the orientation of object (generally, for
equipment)
(1: if the object is parallel to the longitudinal direction of the offshore plant, 0: otherwise)
COG position Coordinates of the center of gravitation of the object
Table 3-3 Data type and properties of the target value according to the attributes Target
value Data type
Properties according to the attributes
Order Orientation COG.x, COG.y, COG.z Standard
value
Double or integer
0, 1, …, n-1 (n: total number of modules)
Binary value Real value Boundary
type
Enumerator type
EXT, MAX,
MIN EXT EXT, MAX, MIN,
PRO Unit Enumerator
type None None meter (M)
Figure 3-3 shows examples of representing rules as the object information. For example, the “Living quarter” should be placed upwind direction of the offshore plant topside to minimize the effects of the hydrocarbon release. This knowledge can be represented as the object information: (E002, Living quarter, Order, 0_EXT). As
another example, the “Pig launcher” should be face outboard of the offshore plant to minimize the possibility of any projectiles hitting personnel or other equipment (API, 2001). This knowledge can be represented as the object information: (E003, Pig launcher, Orientation, 0_EXT). If a certain equipment (“Equipment 1”) needs to be arranged in a mezzanine deck (e.g., z=44m), it can be expressed by defining the object information using the “COG.z” attribute: (E004, Equipment 1, COG.z, 47_PRO_M). If another equipment (“Equipment 2”) is required to be arranged in a process deck (e.g., z=38m), it can be expressed as the object information: (E005, Equipment 2, COG.z, 44_MAX_M).
Figure 3-3 Examples of the object information