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--- modeling_of_activities_and_processes [2011/10/20 21:50]
peter [2. Specification of how objects are involved in occurrences]
+++ modeling_of_activities_and_processes [2018/11/02 21:31]
andries [Occurrences, activities, processes and events]
@@ Line 1: / Line 1: @@
-===== Occurrences, activities, processes and events =====
+====== Modeling of occurrences, activities, processes and events ======
-An occurrence is in its widest sense anything that happens. This includes human activities, but also physical and (bio)chemical processes, control processes, events and physical phenomena. Processes includes both discrete processes and continuous processes. A discrete process consists of a sequence of discrete process steps or actions. Examples of discrete processes are business processes in which various persons prive a contribution in a process, mechanical production processes in the mechanical industry and batch processes in the chemical industry. A continuous process is a process that is an operation on a continuous stream of raw material to produce one or more continuous streams of product materials. Examples of continuous processes are the flowing of water in a river, the operation of an electric power generation plant and the various refinery processes. An occurrence in fact always happens over time, but especially for events the duration often can be neglected. All these kinds of occurrences can be modelled in Gellish.
+An occurrence is in its widest sense anything that happens. This includes human activities, but also physical and (bio)chemical processes, control processes, events and physical phenomena. Processes includes both discrete processes and continuous processes. A discrete process consists of a sequence of discrete process steps or actions. Examples of discrete processes are business processes in which various persons provide a contribution in the process, mechanical production processes in the mechanical industry and batch processes in the chemical industry. A continuous process is a process that is an operation on a continuous stream of raw material to produce one or more continuous streams of product materials. Examples of continuous processes are the flowing of water in a river, the operation of an electric power generation plant and the various refinery processes. An occurrence in fact always happens over time, but in some cases, such as events, the duration can be neglected. All these kinds of occurrences can be modeled in Gellish in a similar way.
-===== 1. Classification of occurrences =====
+====== 1. Classification of occurrences ======
-Occurrences, activities, processes and events can be classified by nouns as well as by verbs, such as the classification of a human activity as a walk or as walking. Both kinds of terms are included in the Gellish Dictionary. Most kinds of occurrences have an active form, a passive form and a noun form and sometimes other forms in the dictionary. For example: act, acting and action, but also activity. All such forms are treated as synonyms in Gellish English. Each individual activity, process or event shall be classified explicitly, for ezxample as follows:
+Occurrences, and its subtypes: activities, processes and events, can be classified by kinds of occurrences, whereas the names of those kinds consists either of nouns or of verbs. For example, a particular individual human activity can be classified as a 'walk' or as 'walking'. Both kinds of terms are considered as being equivalent denotations of the same kind of occurrence. Therefore both such terms are included in the Gellish Dictionary as synonyms. Kinds of occurrences can be denoted by terms in an active form, a passive form and a noun form and sometimes other forms. For example: act, acting and action, but also activity. All such forms are treated as synonyms in Gellish. \\
-^UID of left hand object^Name of left hand object^UID of fact^UID of relation type^Name of relation type^UID of right hand object^Name of right hand object^
+Each individual activity, process or event shall be classified explicitly, for example as follows:
+^UID of left hand object^Name of left hand object^UID of idea^UID of kind of relation^Name of kind of relation^UID of right hand object^Name of right hand object^
 | 1 | compr-1 | 101 | 1225 | is classified as a | 191936 | compression|
-An occurrence, activity, process or event describes the behaviour of the objects involved in that occurrence as well as their mutual interaction. This means that an occurrence is an interaction between two or more objects. Therefore, an occurrence can be expressed in Gellish English as a higher order relation, being a relation with usually more than two related objects. The details of an occurrence are expressed by the specification of the objects that are involved in the interaction, especially in the various roles that they play.
+An occurrence, activity, process or event is further specified by describing the kinds of behavior of the objects that are involved in the occurrence, as well as their mutual interaction. This means that an occurrence is an interaction between two or more objects. Thus more than two objects can be related because of their participation in one occurrence. It is even possible that a variable number of objects are involved over time in one occurrence. For example in a project or a meeting. The modeling of occurrences therefore requires that it should be possible that more than two objects are involved in one occurrence. This can be achieved in Gellish by modeling occurrences as 'objects' that represent higher order (or variable order) relations, being relations with typically more than two related objects. The details of an occurrence are expressed by the specification of the objects that are involved in the interaction, especially in the various roles that they play.
-===== 2. Specification of how objects are involved in occurrences =====
+====== 2. Specification of how objects are involved in occurrences ======
-An occurrence is a higher order relation, because an occurrence is an interaction of several objects. This means that several objects are involved in an occurrence, each with its own role, although often only one or two objects with their roles are modeled. The roles that objects play in an occurrence is modeled in Gellish by the specification of a number of facts, each of which specifies that an object plays a particular role in the occurrence, whereas each fact is specified on a separate line in the database table. These involvement relations are described by expressions that use relation types that are subtypes of the <is involved in> relation type. \\
+An occurrence is modeled as a higher order relation, because an occurrence is an interaction of several objects. This means that several objects are involved in an occurrence, each with its own role, although often only the involvement of one or two objects with their roles are specified. The roles that various objects play in an occurrence are modeled in Gellish by the specification of a different expressions for each involved object. Each of such an expression specifies that an object plays a particular role in the occurrence. This results in several lines with involvement relations. The involvement relations are described by expressions that use kinds of relations that are subtypes of the <is involved in> relation type. \\
 For example:
-^Name of left hand object^Name of relation type^Name of right hand object^
+^Name of left hand object^Name of kind of relation^Name of right hand object^
 | fluid-1 | is input in | heat transfer-1|
-The Gellish English Dictionary contains a large number of relation types, to describe ways in which objects can be involved in occurrences, processes and activities. For example:
+The Gellish English Dictionary contains a large number of kinds of involvement relations that describe ways in which objects can be involved in occurrences, processes and activities. For example:
   * is performer of
   * is enabler of
@@ Line 26: / Line 27: @@
   * etc.
-If only the two roles are of interest, the roles of the performer and of the subject, then it is allowed in Gellish to express the occurrence as a binary relation. For example, the fact that pump P-101 pumps fluid S-1 can be expressed as follows: \\
+If only the two roles are of interest, the roles of a performer and of a subject, then it is allowed in Gellish to express the occurrence as a binary relation. For example, the idea: 'pump P-101 pumps fluid S-1' can be expressed as follows: \\
-^UID of left hand object^Name of left hand object^UID of fact^UID of relation type^Name of relation type^UID of right hand object^Name of right hand object^
+^UID of left hand object^Name of left hand object^UID of idea^UID of kind of relation^Name of kind of relation^UID of right hand object^Name of right hand object^
 | 1 | P-101 | 101 | 194201 | pumping | 2 | S-1|
-The UID of the fact (in the example fact 101) is the identifier of the occurrence. In this case the occurrence is not given a name, but as a guideline it is recommended to use the concatenation of the relation type and the subject as its name, so that the name of the process in the example would be ‘pumping of S-1’.
+The UID of the idea (in the example idea 101) is the identifier of the occurrence. In this example the individual occurrence is not given a name. However, as a guideline it is recommended that software generates a name that is the concatenation of the name of the kind of relation, the string ' of ' and the name of the individual subject. In the example the name of the process would be ‘pumping of S-1’.
-===== 3. Definition of kinds of occurrences, activities, processes and events =====
+====== 3. Definition of kinds of occurrences, activities, processes and events ======
-Occurrences that do not exist yet in the Gellish English dictionary can be added in a similar way as defining physical objectsby obeying the [wiki:"Proper definition of a concept" rules for proper definitions] in Gellish English. A kind of occurrence shall be defined as a subtype of an existing kind of occurrence and facts that are by definition true shall be added to complete the definition. \\
+Occurrences that do not exist yet in the Gellish dictionary can be added in a similar way as defining physical objects by obeying the [wiki:"Proper definition of a concept" rules for proper definitions]. A kind of occurrence shall be defined as a subtype of an existing kind of occurrence and given a textual description, whereas facts that are by definition the case shall be added to complete the definition. \\
-In general, generic kinds of activities and processes are independent of the subject of the occurrence, and independent of the performer or the enabler. For example, the activity 'design' or 'operate' does not include an indication of what is designed or operated. However, more specialised ‘qualified’ activities often do include the subject of the activity or process. For example, "design a pump" or "operate a facility". In such a case the definition of such a kind of occurrence should include and explicit relation that states that it has by definition as subject a particular kind of thing. For example: \\
+Note that there is a distinction between generic kinds of occurrences and kinds of occurrences that have by definition an intrinsic performer or enabler. In general, generic kinds of activities and processes are independent of the subject of the occurrence, and independent of the performer or the enabler. For example, the activity 'design' or 'operate' does not include an indication of what is designed or operated. However, more specialized ‘qualified’ activities often do include the subject of the activity or process. For example, "design a pump" or "operate a facility". In such a case the definition of such a kind of occurrence should include and explicit relation that states that it has by definition as subject a particular kind of thing. For example the concept 'design a pump' is defined as follows: \\
-^Name of left hand object^Name of relation type^Name of right hand object^
+^Name of left hand object^Name of kind of relation^Name of right hand object^Partial definition^
-| design a pump | is a qualification of | design|
+| design a pump | is a qualitative subtype of | design|where the subject is a pump.|
-| design a pump | has by definition as subject a | pump|
+| design a pump | has by definition as subject a | pump| |
-Similar considerations apply for specific activities that include a specific subject. For example, the specific activity called 'design P-101" is by definition a design of a thing called P-101. This is specified as follows: \\
+Similar considerations apply for individual activities that include a specific individual object as its subject. For example, the activity called 'design of P-101" is by definition a design of a thing called P-101. This is specified as follows: \\
-^Name of left hand object^Name of relation type^Name of right hand object^
+^Name of left hand object^Name of kind of relation^Name of right hand object^
-| design of P-101 | is classified as a | design of a pump
+| design of P-101 | is classified as a | design of a pump|
-| design of P-101 | has as subject | P-101
+| design of P-101 | has as subject | P-101|
-===== 4. Specification of activity sequences =====
+Note that the kind of relation 'has by definition as subject a' classifies a relation between two kinds, whereas the kind of relation 'has as subject' classifies a relation between two individual things.
-Often it is required to specify in which sequence activities or chains of shall be or are performed. This may result in activity networks. For example, in activity scheduling for testing, commissioning and start up of facilities or to describe a maintenance procedure. This can be done for sequences of kinds of activities, but also for sequences individual activities, or for procuderes in which typical activity sequence is describedthat shall be repeated every time that the procedure is followed. \\
+====== 4. Specification of activity sequences ======
-For example, the following activity sequence may describe steps that shall be taken during a planned maintenance shut-down (also called a turnaround) of facility:
-^Name of left hand object^Name of relation type^Name of right hand object^
+Often it is required to specify in which sequence activities or chains of activities shall be or are performed. This may result in activity networks. For example, a sequence of activities that specifies a schedule for testing, commissioning and start up of a facility or the activity sequence that describes a maintenance procedure. Sequences can be specified for kinds of activities, but also sequences of individual activities, or in procedures in which a typical (individual) activity sequence is described that shall be repeated every time that the procedure is followed. \\
+For example, a generic activity sequence that describes steps that shall be taken during a planned maintenance shut-down (also called a turnaround) of facility may specify a sequence of kinds of activities. For example as follows:
+^Name of left hand object^Name of kind of relation^Name of right hand object^
 | purge a vessel | shall occurs after a | drain a vessel|
 | inspect a vessel | shall occurs after a | purge a vessel|
-Whereas a sequence of individual activities is expressed as follows:
+Typical activities are activities about individual things. Usually they are modeled as individual activities. When used in a procedure, the represent imaginary activities, whereas the real activities repeatedly use the procedure as a template. A sequence of typical individual activities uses other kinds of relations than above. Such a detailed procedure is expressed as follows:
-^Name of left hand object^Name of relation type^Name of right hand object^
+^Name of left hand object^Name of kind of relation^Name of right hand object^
 | assemble system A | occurs after | clean system A|
 | test system A | occurs after | assemble system A |
+Further details, for example about specifying partly overlapping activities, are given in the book 'Semantic Information Modeling Methodology'.
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