Activity Models – Computational Modeling Work-Bench

Activity models capture collections of determinate, concurrent behavior, focussing on their dependencies, timing, and resource usage. The model is therefore convenient to specifiy logistic processes, but can also capture data processing systems. The atomic pieces of behavior are called actions and have a specified (fixed or worst-case) duration. A single activity is represented as a graph with such actions as its vertices and edges capturing depdencies between actions, as well as dependencies on shared resources. Activities are determinate, if an activity is executed, all its actions are executed and specified ordering is respected.

An activity model, defines a collection of such activities and the possible sequences of activities that a given system may perform. A particular property of the activity model is that the execution of subsequent activities may overlap in time. Often, activities are executed in a pipelined manner, following the transfer of a resource from one activity to the next. Activity sequences can be done in the form of simple lists, or using Finite State Automata, possibly controlled by event feedback received from executed activities.

The behavior of activity models is captured using max-plus algebra. The state of the system is captured by a max-plus vector of resource availability times. Starting and completion times of actions can be expressed as (max-plus-) linear combinations of the resource availabilities and the effect on system state (resource availability) of an entire activity can be captured by max-plus matrix-vector multiplication. An activity model that executes a sequence of different activities can be viewed as a switching max-plus-linear system.

Users can define activity models using the Eclipse LSAT™ (Logistics Specification and Analysis Tool ) tool ^[1]. This tool embeds a domain-specific language ^[2] for activity models and some related analysis methods ^[3]. A case study of modelling the wafer logistics in lithography machines is presented in ^[4].

Selected Related Publications

2023

Mohamadkhani, Alireza; Geilen, Marc; Voeten, Jeroen; Basten, Twan

Modeling and analysis of switching max-plus linear systems with discrete-event feedback Journal Article

In: Discrete Event Dynamic Systems, vol. 33, no. 3, pp. 341–372, 2023, ISSN: 0924-6703.

Abstract | Links | BibTeX

@article{MGVB23,

title = {Modeling and analysis of switching max-plus linear systems with discrete-event feedback},

author = {Alireza Mohamadkhani and Marc Geilen and Jeroen Voeten and Twan Basten},

url = {https://doi.org/10.1007/s10626-023-00382-y},

doi = {10.1007/s10626-023-00382-y},

issn = {0924-6703},

year  = {2023},

date = {2023-08-01},

urldate = {2023-08-01},

journal = {Discrete Event Dynamic Systems},

volume = {33},

number = {3},

pages = {341–372},

publisher = {Kluwer Academic Publishers},

address = {USA},

abstract = {Switching max-plus linear system (SMPLS) models are an apt formalism for performance analysis of discrete-event systems. SMPLS analysis is more scalable than analysis through other formalisms such as timed automata, because SMPLS abstract pieces of determinate concurrent system behavior into atomic modes with fixed timing. We consider discrete-event systems that are decomposed into a plant and a Supervisory Controller (SC) that controls the plant. The SC needs to react to events, concerning e.g. the successful completion or failure of an action, to determine the future behavior of the system, for example, to initiate a retrial of the action. To specify and analyze such system behavior and the impact of feedback on timing properties, we introduce an extension to SMPLS with discrete-event feedback. In this extension, we model the plant behavior with system modes and capture the timing of discrete-event feedback emission from plant to SC in the mode matrices. Furthermore, we use I/O automata to capture how the SC responds to discrete-event feedback with corresponding mode sequences of the SMPLS. We define the semantics of SMPLS with events using new state-space equations that are akin to classical SMPLS with dynamic state-vector sizes. To analyze the extended models, we formulate a transformation from SMPLS with events to classical SMPLS with equivalent semantics and properties such that performance properties can be analyzed using existing techniques. Our approach enables the specification of discrete-event feedback from the plant to the SC and its performance analysis. We demonstrate our approach by specifying and analyzing the makespan of a flexible manufacturing system.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

2022

Sanden, Bram; Geilen, Marc; Reniers, Michel; Basten, Twan

Partial-Order Reduction for Supervisory Controller Synthesis Journal Article

In: IEEE Transactions on Automatic Control, vol. 67, no. 2, pp. 870-885, 2022.

Links | BibTeX

2021

Sanden, Bram; Blankenstein, Yuri; Schiffelers, Ramon; Voeten, Jeroen

LSAT: Specification and Analysis of Product Logistics in Flexible Manufacturing Systems Proceedings Article

In: 2021 IEEE 17th International Conference on Automation Science and Engineering (CASE), pp. 1-8, 2021.

Links | BibTeX

2020

Basten, Twan; Bastos, João; Medina, Róbinson; Sanden, Bram; Geilen, Marc C. W.; Goswami, Dip; Reniers, Michel A.; Stuijk, Sander; Voeten, Jeroen P. M.

Scenarios in the Design of Flexible Manufacturing Systems Book Chapter

In: System-Scenario-based Design Principles and Applications, pp. 181–224, Springer International Publishing, Cham, 2020.

Links | BibTeX

2018

Sanden, Bram

performance analysis and optimization of supervisory controllers PhD Thesis

Eindhoven University of Technology, 2018.

BibTeX

2017

Adyanthaya, Shreya; Ara, Hadi Alizadeh; Bastos, João; Behrouzian, Amir; Sánchez, Róbinson Medina; Pinxten, Joost; Sanden, Bram; Waqas, Umar; Basten, Twan; Corporaal, Henk; Frijns, Raymond; Geilen, Marc; Goswami, Dip; Hendriks, Martijn; Stuijk, Sander; Reniers, Michel; Voeten, Jeroen

XCPS: A Tool to Explore Cyber Physical Systems Journal Article

In: SIGBED Rev., vol. 14, no. 1, pp. 81–95, 2017.

Abstract | Links | BibTeX

2016

Sanden, Bram; Bastos, João; Voeten, Jeroen; Geilen, Marc; Reniers, Michel A.; Basten, Twan; Jacobs, Johan; Schiffelers, Ramon R. H.

Compositional specification of functionality and timing of manufacturing systems Proceedings Article

In: 2016 Forum on Specification and Design Languages, FDL 2016, Bremen, Germany, September 14-16, 2016, pp. 1–8, 2016.

Links | BibTeX

2015

Sanden, Bram; Reniers, Michel; Geilen, Marc; Basten, Twan; Jacobs, Johan; Voeten, Jeroen; Schiffelers, Ramon

Modular model-based supervisory controller design for wafer logistics in lithography machines Proceedings Article

In: 2015 ACM/IEEE 18th International Conference on Model Driven Engineering Languages and Systems (MODELS), pp. 416-425, 2015.

Links | BibTeX

References

Bram Sanden and Yuri Blankenstein and Ramon Schiffelers and Jeroen Voeten (2021): LSAT: Specification and Analysis of Product Logistics in Flexible Manufacturing Systems. In: 2021 IEEE 17th International Conference on Automation Science and Engineering (CASE), pp. 1-8, 2021.
Bram Sanden and João Bastos and Jeroen Voeten and Marc Geilen and Michel A. Reniers and Twan Basten and Johan Jacobs and Ramon R. H. Schiffelers (2016): Compositional specification of functionality and timing of manufacturing systems. In: 2016 Forum on Specification and Design Languages, FDL 2016, Bremen, Germany, September 14-16, 2016, pp. 1–8, 2016.
Bram Sanden (2018): performance analysis and optimization of supervisory controllers. Eindhoven University of Technology, 2018.
Bram Sanden and Michel Reniers and Marc Geilen and Twan Basten and Johan Jacobs and Jeroen Voeten and Ramon Schiffelers (2015): Modular model-based supervisory controller design for wafer logistics in lithography machines. In: 2015 ACM/IEEE 18th International Conference on Model Driven Engineering Languages and Systems (MODELS), pp. 416-425, 2015.