Process Choreographies on the Blockchain (Sommersemester 2019)

Lecturer: Prof. Dr. Mathias Weske (Business Process Technology)

General Information

• Weekly Hours: 4
• Credits: 6
• Graded: yes
• Enrolment Deadline: 26.04.2019
• Teaching Form: Seminar / Project
• Enrolment Type: Compulsory Elective Module
• Course Language: English
• Maximum number of participants: 8

Programs, Module Groups & Modules

Description

The slides of the introductory meeting can be found here.

Within the last few years, blockchain technology has revived the field of choreography modeling and enactment in Business Process Management (BPM) [4]. In contrast to traditional process specifications, which usually focus on concrete activities within the confinements of a single organization, choreographies describe business contracts. They model the interactions between partners to reach a common business goal, abstracting from internal and confidential details of individual participants. In a sense, choreography models provide an interaction blueprint for each participant; the model tells them exactly when to exchange which message with which participant, embedded in a set of ordering and synchronization constraints.

However, after negotiating and agreeing on a choreography model towards a particular business goal, some important questions emerge: Who is responsible for monitoring the correct execution of a choreography? Who makes sure all necessary messages are sent and that all decisions are made correctly according to specification? After all, it is important that every participant honors their part of the choreography. Unfortunately, in an inter-organizational setting there usually is no single entity or third party which enjoys enough trust from all participants to take on this role of a central coordinator. For this reason, choreography models are often regarded to be of a purely descriptive nature that lacks the "automatable" execution character of other process specifications.

This perception has changed with the advent of blockchain technology, especially its smart contract capabilities. Second-generation blockchains promise a distributed and tamper-proof environment in which arbitrary programs can be stored and executed. In particular, contractual agreements can be expressed as code which strictly enforces arbitrary constraints [5]. Based on these capabilities, there has been work on automatically generating smart contracts that enforce the behavior specified in a choreography model [1]. Several prototypical implementations have since been developed [2, 3], with novel research being published constantly.

In this project seminar, we want to catch up: Our main goal is the development of a web-based choreography modeling application capable of generating smart contracts from choreography models. Apart from technical challenges there are important conceptual decisions to be made as well. During the seminar, we want to dynamically discover and tackle these challenges, and end up with a usable proof-of-concept prototype that can compete with existing solutions.

Requirements

The project seminar is suitable for Master's student interested in BPM and blockchain technology. Necessary fundamental knowledge will be taught as part of the seminar. Some previous experience with blockchain development, Javascript (React) and/or Web3 is helpful.

Literature

• [1] Weber, Ingo, et al. "Untrusted business process monitoring and execution using blockchain." International Conference on Business Process Management. Springer, Cham, 2016.
• [2] López-Pintado, Orlenys, et al. "Caterpillar: A blockchain-based business process management system." Proceedings of the BPM Demo Track and BPM Dissertation Award co-located with 15th International Conference on Business Process Modeling (BPM 2017), Barcelona, Spain. 2017.
• [3] Tran, A., Qinghua Lu, and Ingo Weber. "Lorikeet: A model-driven engineering tool for blockchain-based business process execution and asset management." Demo Track at BPM 2018 (2018): 56-60.
• [4] Mendling, Jan, et al. "Blockchains for business process management-challenges and opportunities." ACM Transactions on Management Information Systems (TMIS) 9.1 (2018): 4.
• [5] Clack, Christopher D., Vikram A. Bakshi, and Lee Braine. "Smart contract templates: foundations, design landscape and research directions." arXiv preprint arXiv:1608.00771 (2016).

Learning

After an initial research phase with regular lectures and student presentations, we will switch to a SCRUM-like development phase. Details can be discussed and adjusted within the group.

Examination

Students will be graded by:

• one individual presentation in the first third of the semester
• one final presentation at the end of the semester
• participation during the semester
• an implemented prototype together with a documentation

Dates

We will meet on Monday, April 8th, at 15:15 in room A-1.1 for the introductory meeting.

The slides of the introductory meeting can be found here.

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