@proceedings {2024:asianplop,
	title = {Decentralized Task Execution Patterns},
	year = {2024},
	month = {March},
	address = {Fujisawa City, Kanagawa Prefecture, Japan},
	abstract = {Decentralized task execution requires to assign planning, execution and control roles and responsibilities to at least two distinct parties. These include making decisions about {\textquoteleft}{\textquoteleft}who does what when{\textquoteright}{\textquoteright} so that one party can track the progress and the outcome of tasks executed by another party. In this paper we outline the design space for decentralized task execution by presenting 18 different patterns, going from imperative task execution all the way to autonomous task execution. We will distinguish how decisions about who performs a task, what needs to be done and when to do it can be made by different parties and how these alternative decision-making locations impact the interactions between the parties responsible to plan, execute and control the task execution. The patterns are applicable within human organizations with many actors delegating or performing multiple tasks but also to fully automated systems, e.g., distributed operating systems, intelligent autonomous vehicles, blockchain-based workflow engines or high throughput job schedulers.},
	keywords = {patterns, Workflow Management Systems, workflow patterns},
	author = {Cesare Pautasso}
}
@inproceedings {2017:benchflow:wesoa,
	title = {Lessons Learned from Evaluating Workflow Management Systems},
	year = {2017},
	month = {November},
	publisher = {Springer},
	address = {Malaga, Spain},
	abstract = {Workflow Management Systems (WfMSs) today act as service composition engines and service-oriented middleware to enable the execution of automated business processes. 
Automation based on WfMSs promises to enable the model-driven construction of flexible and easily maintainable services with high-performance characteristics. 
In the past decade, significant effort has been invested into standardizing WfMSs that compose services, with standards such as the Web Services Business Process Execution Language (WS-BPEL) or the Business Process Model and Notation (BPMN).
One of the aims of standardization is to enable users of WfMSs to compare different systems and to avoid vendor lock-in. 
Despite these efforts, there are many expectations concerning portability, performance efficiency, usability, reliability and maintainability of WfMSs that are likely to be unfulfilled.
In this work, we synthesize the findings of two research initiatives that deal with WfMSs conformance and performance benchmarking to distill a set of lessons learned and best practices. 
These findings provide useful advice for practitioners who plan to evaluate and use WfMSs and for WfMS vendors that would like to foster wider adoption of process-centric service composition middleware. },
	keywords = {BenchFlow, Lessons Learned, Workflow Management Systems},
	author = {J{\"o}rg Lenhard and Vincenzo Ferme and Simon Harrer and Matthias Geiger and Cesare Pautasso}
}
@proceedings {2017:benchflow:bpmds,
	title = {Performance Comparison Between BPMN 2.0 Workflow Management Systems Versions},
	year = {2017},
	month = {June},
	publisher = {Springer},
	address = {Essen, Germany},
	abstract = {Software has become a rapidly evolving artifact and Workflow Management Systems (WfMSs) are not an exception. WfMSs{\textquoteright} changes may impact key performance indicators or resource consumption levels may change among different versions. Thus, users considering a WfMS upgrade need to evaluate the extent of such changes for frequently issued workload.  Deriving such information requires running performance experiments with appropriate workloads. 
In this paper, we propose a novel method for deriving a structurally representative workload from a given business process collection, which we later use to evaluate the performance and resource consumption over four versions of two open-source WfMSs, for different numbers of simulated users. In our case study scenario the results reveal relevant variations in the WfMSs{\textquoteright} performance and resource consumption, indicating a decrease in performance for newer versions.},
	keywords = {BenchFlow, BPMN, Performance Regression, Performance Testing, workflow engine, Workflow Management Systems},
	author = {Vincenzo Ferme and Marigianna Skouradaki and Ana Ivanchikj and Cesare Pautasso and Frank Leymann}
}
@article {benchflow:2017:icse,
	title = {Workflow Management Systems Benchmarking: Unfulfilled Expectations and Lessons Learned},
	year = {2017},
	month = {May},
	address = {Buenos Aires, Argentina},
	abstract = {Workflow Management Systems (WfMSs) are a type of middleware that enables the execution of automated business processes. Users rely on WfMSs to construct flexible and easily maintainable software systems. Significant effort has been invested into standardising languages for business processes execution, with standards such as the Web Services Business Process Execution Language 2.0 or the Business Process Model and Notation 2.0.
Standardisation aims at avoiding vendor lock-in and enabling WfMS users to compare different systems. The reality is that, despite standardisation efforts, different independent research initiatives show that objectively comparing WfMSs is still challenging. As a result, WfMS users are likely to discover unfulfilled expectations while evaluating and using these systems. In this work, we discuss the findings of two research initiatives dealing with WfMSs benchmarking, presenting unfulfilled expectations and lessons learned concerning WfMSs{\textquoteright} usability, reliability, and portability.  Our goal is to provide advice for practitioners implementing or planning to use WfMSs.},
	keywords = {Lessons Learned, Workflow Management Systems},
	doi = {10.1109/ICSE-C.2017.126},
	author = {Vincenzo Ferme and J{\"o}rg Lenhard and Simon Harrer and Matthias Geiger and Cesare Pautasso}
}
@conference {benchflow:2016:caise,
	title = {Micro-Benchmarking BPMN 2.0 Workflow Management Systems with Workflow Patterns},
	booktitle = {Proc. of the 28th International Conference on Advanced Information Systems Engineering (CAISE)},
	year = {2016},
	month = {June},
	pages = {67--82},
	publisher = {Springer},
	organization = {Springer},
	address = {Ljubljana, Slovenia},
	abstract = {Although Workflow Management Systems (WfMSs) are a key component in workflow technology, research work for assessing and comparing their performance is limited. This work proposes the first micro- benchmark for WfMSs that can execute BPMN 2.0 workflows. To this end, we focus on studying the performance impact of well-known workflow patterns expressed in BPMN 2.0 with respect to three open source WfMSs (i.e., Activiti, jBPM and Camunda). We executed all the experiments under a reliable environment and produced a set of meaningful metrics. This paper contributes to the area of workflow technology by defining building blocks for more complex BPMN 2.0 WfMS benchmarks. The results have shown bottlenecks on architectural design decisions, resource utilization, and limits on the load a WfMS can sustain, especially for the cases of complex and parallel structures. Experiments on a mix of workflow patterns indicated that there are no unexpected performance side effects when executing different workflow patterns concurrently, although the duration of the individual workflows that comprised the mix was increased.},
	keywords = {BenchFlow, benchmarking, BPMN, Microbenchmark, workflow engine, Workflow Management Systems, workflow patterns},
	doi = {10.1007/978-3-319-39696-5_5},
	url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2016-05\&engl=0},
	author = {Marigianna Skouradaki and Vincenzo Ferme and Cesare Pautasso and Frank Leymann and Andr{\'e} van Hoorn}
}
