Activity

Activity is the collective term for operations carried out in BPM. Among activities, items that cannot be divided any further and items that consist of complex operations may be explicitly referred to as “tasks” and “sub-processes” respectively.

Outline of activity
The word activity is used to represent a variety of meanings in daily life. For example, it can be used as the general term for outdoor leisure, support for rehabilitation treatment, and community exchange, all of which are related to actions, movement, and operations. The word activity in the BPM field is also generally used to mean operations executed in business processing.

Activities are considered to include a wide range of activities that can be completed in 5 minutes, one week or longer. In BPMN, the task or the source activity (meaning that the relevant activity cannot be split any further) is used when it is necessary to clearly specify that the relevant activity is a single unit of operations that cannot be split any further. When it is necessary to clearly specify that the activity is a unit of complex operations, a sub-process (or the process if applicable) is used. The task (Atomic activity) becomes a leaf node in the tree structure that represents the activity in the process. digraph sample { graph [rankdir=LR]; //左右描画 node [shape=box, style=rounded]; //デフォルトノード定義 edge [labelfloat=true]; //テキスト回り込みOFF A [label=" Check the \n document "]; B [label="Add \n comments"]; C [label=" Print out \n the document "]; A->B->C [style=invis]; }

Special XPDL activity
In XPDL, the activity set or reusable sub-process that is expected to be reused through an external call may be called the subflow. In addition, the activity set or embedded sub-process that is not expected to be reused may be called the block activity. These expressions do not apply to BPMN.

Differences between the BPMN and XPDL definitions of activity
In the BPMN specification (PDF: 318p) administered by the OMG, activities are clearly distinguished from other graphical objects. The flow object, an element of BPD, consists of three elements, namely (1) events, (2) activities, and (3) gateways. Activities do not include the gateways.

On the other hand, in the XML process definition language (XPDL) administered by WfMC, all the so-called BPMN flow objects may be called the process activity. That is, gateways and events may be called the process activity. Gateways are specifically called the route activity.

These expressions cannot be used in BPMN notation.

Activity illustration method
digraph sample1 { ///////▼デフォルト定義▼/////// graph [rankdir=LR]; //左右描画 node [shape=box, style=rounded]; //デフォルトノード定義 edge [labelfloat=true]; //テキスト回り込みOFF ///////▼個別ノード定義▼/////// X [label="", shape=circle]; Y [label="",shape=circle, style=bold]; ///////▼エッヂの定義▼/////// X->ActivityA ; ActivityA->ActivityB [arrowtail=rcrowlvee]; ActivityB->Y; ActivityA->Y [arrowtail=odiamond, weight=0.2]; }

When activities are illustrated based on BPMN notation, they are presented in a round-edged rectangle.

Four markers may be presented: loop, multi-instance, compensation and ad-hoc. They are illustrated in the table below.


 * Loop: Activities are repeated.
 * Multi-instance: A number of instances are created simultaneously.
 * Ad-hoc: The task number in the sub-process cannot be defined.
 * Compensation: Special activities that may be called when a cancellation is implemented through tasks in the process, and which have no input-output sequence flows; the compensation is usually described in places other than the ordinary flow, and is connected with tasks that may be called through the links (the connection object). The compensation is used in combination with the loop or the multi-instance.

(*) It must be noted that the multi-instance marker notation in BPMN1.0 is different from that in BPMN1.1.

History

 * Feb. 1999: WfMC; Terminology & Glossary, (PDF: 65p)
 * Oct. 2002: WfMC; Workflow Process Definition Interface - XML Process Definition Language, (PDF: 499KB, 87p)
 * May 2004: BPMI; Business Process Modeling Notation, version 1.0
 * Oct. 2005: WfMC; Process Definition Interface - XML Process Definition Language (XPDL2.0), (PDF: 2.4MB, 164p )
 * Feb. 2006: OMG; Business Process Modeling Notation Final Adopted Specification
 * Jan. 2008: OMG; Business Process Modeling Notation, version 1.1, (PDF: 318p)

Related Articles

 * BPMN
 * Business process diagram
 * Task
 * Event
 * Gateway
 * Sequence Flow
 * Sub-process
 * XPDL
 * XOR-Split
 * BPEL
 * ABC analysis (Activity Based Costing)
 * Swimlane
 * Intermediate Event
 * Conditional Sequence Flow
 * Message Flow
 * Default Sequence Flow
 * Fork

Referencs

 * Process Definition Interface - XML Process Definition Language
 * (Document Number WFMC-1025 Document Status. Final Approved)(XPDL2.1 - Final Approved)(March 2008, WfMC) (PDF: 3.1MB, 216p)
 * XPDL2.0 - Process model conversion and the integration of BPMN (Translation: August 2007; J-SYS Software Co., Ltd.) (PDF: 12p)