Activity cycle diagram

An activity cycle diagram (ACD) is a graphical modeling tool used to depict interactions among objects within a system. It is commonly used in the field of discrete event simulation, following the activity-based modeling paradigm.

This approach models how system components move between different states over time—most commonly "active" and "dead"—focusing on their life cycles. For example, in a hospital simulation, a patient may alternate between waiting (dead state) and receiving treatment (active state). In contrast, a process-oriented or event-based model would define the patient's journey as a sequence of steps—such as "check-in," "wait," "treatment," and "discharge"—emphasizing the flow of control rather than the states of system components.

Activity-based modeling is often considered a natural and intuitive way to represent system behavior over time.

Origin

The ACD was developed in the 1960s, building on the flow diagram method introduced by K. D. Tocher. It was created to support activity-based modeling in simulation and has since been applied across various domains.

Characteristics

An activity cycle diagram focuses on the life cycle of system components, distinguishing between a "dead" state (idle, not engaged in any activity) and an "active" state (engaged in a process or function). These diagrams are used to model how entities in a system move between these states over time.

Implementation

In activity-based modeling, system dynamics are represented as a network model of the logical and temporal relationships among activities. This makes the ACD well-suited for use with the activity scanning method of simulation execution, which involves continuously checking the system to determine which activities are ready to occur.

External links

INTRODUCTION TO DISCRETE EVENT SIMULATION
MODEL DEVELOPMENT LIFE CYCLE
ACTIVITY CYCLE DIAGRAMS
SIMULATION USING ARENA
ADVANCED SIMULATION USING ARENA
SIMULATION OUTPUT ANALYSIS

Sources

↑ Kang, Donghun; Choi, Byoung K. (2011-02-01). "The extended activity cycle diagram and its generality". Simulation Modelling Practice and Theory. 19 (2): 785–800. doi:10.1016/j.simpat.2010.11.004. ISSN 1569-190X.
↑ Choi, Byoung Kyu; Kang, DongHun (2013-08-07). Modeling and Simulation of Discrete Event Systems. John Wiley & Sons. ISBN 978-1-118-73285-4.
↑ Greasley, Andrew (2019-10-21). Simulating Business Processes for Descriptive, Predictive, and Prescriptive Analytics. Walter de Gruyter GmbH & Co KG. ISBN 978-1-5474-0069-0.
↑ Shi, Jingsheng (1997). "A conceptual activity cycle-based simulation modeling method" (PDF). Proceedings of the 29th conference on Winter simulation - WSC '97. Atlanta, Georgia, United States: ACM Press. pp. 1127–1133. doi:10.1145/268437.268749. ISBN 978-0-7803-4278-1. S2CID 16392452.
↑ Page Jr., Ernest H. (September 1994). Simulation modeling methodology: principles and etiology of decision support (PDF) (PhD thesis). Virginia Polytechnic Institute and State University.

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[1] Kang, Donghun; Choi, Byoung K. (2011-02-01). "The extended activity cycle diagram and its generality". Simulation Modelling Practice and Theory. 19 (2): 785–800. doi:10.1016/j.simpat.2010.11.004. ISSN 1569-190X.

[2] Choi, Byoung Kyu; Kang, DongHun (2013-08-07). Modeling and Simulation of Discrete Event Systems. John Wiley & Sons. ISBN 978-1-118-73285-4.

[3] Greasley, Andrew (2019-10-21). Simulating Business Processes for Descriptive, Predictive, and Prescriptive Analytics. Walter de Gruyter GmbH & Co KG. ISBN 978-1-5474-0069-0.

[4] Shi, Jingsheng (1997). "A conceptual activity cycle-based simulation modeling method" (PDF). Proceedings of the 29th conference on Winter simulation - WSC '97. Atlanta, Georgia, United States: ACM Press. pp. 1127–1133. doi:10.1145/268437.268749. ISBN 978-0-7803-4278-1. S2CID 16392452.

[5] Page Jr., Ernest H. (September 1994). Simulation modeling methodology: principles and etiology of decision support (PDF) (PhD thesis). Virginia Polytechnic Institute and State University.