Content uploaded by Ingo Weber
Author content
All content in this area was uploaded by Ingo Weber on Sep 16, 2020
Content may be subject to copyright.
A preview of the PDF is not available
Controlled flexibility in blockchain-based collaborative business processes
Abstract and Figures
Blockchain technology enables the execution of collaborative business processes involving mutually untrusted parties. Existing tools allow such processes to be modeled using high-level notations and compiled into smart contracts that can be deployed on blockchain platforms. However, these tools do not provide mechanisms to cope with the flexibility requirements inherent to open and dynamic collaboration environments. In particular, existing tools adopt a static role binding approach wherein roles are bound to actors upfront when a process instance is created. Also, these tools do not allow participants to collectively make choices regarding alternative sub-processes or branches in the process model, at runtime. This paper presents a model for dynamic binding of actors to roles in collaborative processes and an associated binding policy specification language. The proposed language is endowed with a Petri net semantics, thus enabling policy consistency verification. Furthermore, the paper introduces a model for consensus-based control-flow flexibility, wherein participants in a process can collectively agree on how to steer the business process within the boundaries defined by control-flow agreement policies. The paper also outlines an approach to compile policy specifications into smart contracts for enforcement. An experimental evaluation shows that the cost of policy enforcement increases linearly with the number of roles, control-flow elements, and policy constraints.
Figures - uploaded by Ingo Weber
Author content
All figure content in this area was uploaded by Ingo Weber
Content may be subject to copyright.
... Their approach allows defining, at design time, patterns such as direct allocation, role-based allocation, and separation of duties. Further improving support for this dimension, López-Pintado et al. (2022) proposed a binding policy specification language allowing to dynamically manage the assignment of participants to roles, and to handle collaborative decision. ...
... Due to the dynamic nature of COBPs, it should be possible to choose and replace participants during the execution of a process (López-Pintado et al. 2022;Prybila et al. 2020). If the public keys of the participants are hardcoded in the smart contract and cannot be changed after deployment, the requirement is not met ...
Smart contracts can be used to support the execution of cross-organizational business processes involving mutually distrusting participants. Model-driven engineering is often used to generate such contracts and requires an appropriate blockchain-enabled process modeling language. Although artifact-centric languages are recommended in this context to support the business objects, lifecycles and cross-organizational process dimensions, most approaches rely on activity-centric languages such as BPMN. The few artifact-centric ones lack integrated support for one or more of these dimensions. To address this issue, in this paper we apply the design science research methodology. The authors propose a set of requirements for artifact-centric and blockchain-enabled business process modeling languages. It is used to evaluate existing work and present the design and demonstration of the B-MERODE language as an improved solution. The models created with the language can be formally verified and used as input to automatically generate smart contracts supporting the required process dimensions.
... 3. Lack of standardization. The absence of standardized tools or guidelines from construction BP models (e.g., BPMN) to SCs generation poses a significant adoption barrier for existing approaches (Liu et al. 2022;López-Pintado et al. 2022;Loukil et al. 2021;Shen et al. 2023). Standardization is crucial to ensure consistency, reliability, and ease of implementation across different projects and organizations. ...
With the digital transformation of the construction industry, the need to improve construction business process collaboration and automation is increasing. However, as construction projects usually involve many stakeholders with complex relationships and insufficient mutual trust, the existing technologies cannot fulfill the requirements of the construction industry. This paper explores the integration of blockchain, smart contracts, and process automation technologies into construction business processes, shedding light on both managerial and technical challenges. The study introduces a comprehensive technical framework meticulously designed to align with the intricate nature of construction practices while focusing on the resolution of legal complexities associated with smart contract applications and the facilitation of process collaboration and automation. The framework comprises three core modules: (1) action definition and extension to process models, (2) standardized mapping for automatic smart contract generation, and (3) smart contract visualization for reliable process collaboration and automation. This multifaceted approach caters to the specific needs of construction management, standardization, interoperability, and visualization. The framework’s practicality is further evaluated through real-world testing within a construction payment case, effectively showcasing its efficacy and applicability in tangible business scenarios. While this paper represents a significant step forward in addressing construction business process collaboration and automation challenges, it acknowledges the necessity for ongoing research and development to refine and expand these innovative solutions to meet the evolving demands of construction management.
... In 2008, Satoshi Nakamoto leveraged blockchain to introduce the highly acclaimed digital currency, bitcoin, a peer-to-peer electronic payment system [31]. Since then, blockchain has been successfully employed in several industries, including medical [32,33], manufacturing [34][35][36][37], energy [38,39], business [40][41][42], and agriculture [43][44][45]. Blockchain is a highly secure distributed ledger shared among a network of participants, who must collectively agree on adding information to the ledger. ...
Requirement engineering (RE), a systematic process of eliciting, defining, analyzing, and managing requirements, is a vital phase in systems engineering. In RE, requirement traceability establishes the relationship between the artifacts and supports requirement validation, change management, and impact analysis. Establishing requirement traceability is challenging, especially in the early stages of a complex system design, as requirements constantly evolve and change. Moreover, the involvement of distributed stakeholders in system development introduces collaboration and trust issues. This paper outlines a novel blockchain-based requirement traceability framework that includes a data acquisition template and graph-based visualization. The template enables dual-level traceability (artifact and object) in the RE processes. The traceability information acquired through the templates is stored in the blockchain, where traces are embedded in blocks’ metadata and data. Furthermore, the blockchain is represented as a Neo4J property graph where traces can be retrieved using Cypher queries, thus enabling a mechanism to query and examine the history of requirements. The framework’s efficacy is showcased by documenting the RE process of an autonomous automotive system. Our results indicated that the framework can record the history of artifacts with constantly changing requirements and can yield secure decentralized ledgers of requirement artifacts. The proposed distributed traceability framework has shown promise to enhance stakeholder collaboration and trust. However, additional user studies should be conducted to bolster our results.
... This study designed a proposed simulation based on a medical waste collaboration process model. The process model describes the collaboration processes [15][16][17][18][19][20] between waste operation processes and documentation operation processes. DES [21][22][23] models the flow of activities, and many DES tools have a split operator to run multiple processes, such as waste operation and documentation operation, simultaneously. ...
Within the overarching theme of “Managing the Digital Transformation of Construction Industry” the 23rd International Conference on Construction Applications of Virtual Reality (CONVR 2023) presented 123 high-quality contributions on the topics of: Virtual and Augmented Reality (VR/AR), Building Information Modeling (BIM), Simulation and Automation, Computer Vision, Data Science, Artificial Intelligence, Linked Data, Semantic Web, Blockchain, Digital Twins, Health & Safety and Construction site management, Green buildings, Occupant-centric design and operation, Internet of Everything. The editors trust that this publication can stimulate and inspire academics, scholars and industry experts in the field, driving innovation, growth and global collaboration among researchers and stakeholders.
To alleviate difficulties in writing smart contracts for distributed blockchain applications, as other research, we propose transformation of Business Process Model and Notation (BPMN) models into blockchain smart contracts. Unlike other research, we use Discrete Event Hierarchical State Machine (DE-HSM) multi-modal modeling to identify collaborative trade transactions that need to be supported by the smart contract and describe how the trade transactions, that may be nested, are supported by a transaction mechanism. We describe algorithms to (i) identify the nested trade transactions and to (ii) transform the BPMN model into blockchains smart contracts that include a transaction mechanism to enforce the transactional properties for the identified trade transactions. The developed proof of concept shows that our approach to automated transformation of BPMN models into smart contracts with the support of privacy and cross-chain interoperability is feasible. The thesis examines and evaluates automatically generated alternative transaction mechanisms to support such transactions using three use cases of varying degree of complexity, namely order processing, supply chain management, and a multi-faceted trade use case. The research enriches the academic dialogue on blockchain technology and smart contracts and proposes potential avenues for future research.
Collaboration of business processes is essential for business-to-business (B2B) processes. Collaboration is interesting and important in connecting the digital context with the physical world (IoT) to feed processes with data or send data. However, it also presents multiple challenges, such as the lack of trust between participants with each other and additional privacy and security problems in the communicated data. Fraud detection is crucial for many type of organisations that deal with B2B transactions (banking, fintech, health, etc.) and are therefore exposed to a high risk of fraud. Fraud detection requires expensive professional investigations and intensive collaboration between processes of different organisations. This issue could be mitigated by effectively managing digital evidence, fostering trust and ensuring security for various stakeholders involved in the business processes. This paper proposes an approach to modelling and deploying any collaborative business process scenario, ensuring trust, security, and data privacy. Collaboration-level agreements are defined as a means to ensure trust, security, and data privacy. To accomplish this, our approach enables the automatic generation Smart Contract templates for the collaboration-level agreement specification involving different stakeholders in the collaboration. The Smart contracts are deployed in a Blockchain to ensure that the collaboration-level agreement conditions are signed by the parties. To validate the feasibility of our approach, a proof-of-concept for a fraud detection scenario is implemented, where different metrics are tested in relation to a set of threats and vulnerabilities.
The recent growth of blockchain has opened the use of technology for supporting the creation of new kinds of trustable systems. Model-driven engineering methodologies have been conceived to facilitate the automatic generation and deployment of software applications starting from the definition and refinement of abstract specification. BPMN choreography diagrams permit the representation of inter-organisational systems from a high-level perspective, just focusing on message exchange. However, the usage of such models in a blockchain-based setting has been limited to scenarios in which parties are involved in single interactions. This aspect becomes significantly relevant when considering complex applications, and in particular those in the realm of the Internet of Things. In these cases, the multiplicity of parties and their actions is crucial and requires novel solutions. In this work, we propose a novel approach for modelling, refining, deploying, and executing a Choreography on the blockchain, taking into account those scenarios in which the model includes multiple-instances. In particular, the considered models are translated into smart contracts able to correctly manage multiplicity. To demonstrate the approach’s feasibility, we designed and presented a Smart Thermostat application, that is executed on the Polygon blockchain.
Multi-party business processes rely on the collaboration of various players in a decentralized setting. Blockchain technology can facilitate the automation of these processes, even in cases where trust among participants is limited. Transactions are stored in a ledger, a replica of which is retained by every node of the blockchain network. The operations saved thereby are thus publicly accessible. While this enhances transparency, reliability, and persistence, it hinders the utilization of public blockchains for process automation as it violates typical confidentiality requirements in corporate settings. In this paper, we propose MARTSIA: A Multi-Authority Approach to Transaction Systems for Interoperating Applications. MARTSIA enables precise control over process data at the level of message parts. Based on Multi-Authority Attribute-Based Encryption (MA-ABE), MARTSIA realizes a number of desirable properties, including confidentiality, transparency, and auditability. We implemented our approach in proof-of-concept prototypes, with which we conduct a case study in the area of supply chain management. Also, we show the integration of MARTSIA with a state-of-the-art blockchain-based process execution engine to secure the data flow.
Distributed Ledger Technology (DLT) and blockchains in particular have been identified as promising foundations to realize inter organizational business processes. Capabilities such as shared data and decision logic defined as smart contracts open up entirely new ways to implement process choreographies. However, current choreography modeling languages solely focus on direct interactions between organizations ; they do not take into account the conceptually new features of blockchains, like shared data and smart contracts. To bridge the gap between choreography modeling and implementation, this paper critically analyzes the assumptions of choreography languages. We propose new language concepts specifically targeting blockchain capabilities, and we define their operational semantics. Our work is evaluated with a proof-of-concept implementation and an analysis of three real-world case studies from the private and the corporate sectors.
Business Process Management provides concepts for enterprises to design, document and execute their business processes. Involved artefacts establish the basis for a profound enhancement of processes, like performance improvements or a substantiate assignment of employees (resources) to tasks. These artefacts comprise process models for documentation purposes or Workflow Management Systems for executing processes.
Those concepts are adopted well within single companies but are barely implemented for inter-organizational processes reasoned in a lack of trust between participating business partners. For instance, questions like who the host of the workflow engine is and thus have sovereignty over the process execution remains open. Besides expensive third parties, we believe that Blockchain Technology bears potential to solve the lack of trust due to automated consensus finding.
We present a Blockchain-based process engine guaranteeing a tamper-proof execution, which is both, highly scalable regarding the size of process models as well as capable of considering employees captured in the organizational perspective of the process model. Comparable approaches suffer from lack of trustworthiness either, are not applicable for large process models, or do not include organisational concerns.
Blockchain has numerous benefits such as decentralisation, persistency, anonymity and auditability. There is a wide spectrum of blockchain applications ranging from cryptocurrency, financial services, risk management, internet of things (IoT) to public and social services. Although a number of studies focus on using the blockchain technology in various application aspects, there is no comprehensive survey on the blockchain technology in both technological and application perspectives. To fill this gap, we conduct a comprehensive survey on the blockchain technology. In particular, this paper gives the blockchain taxonomy, introduces typical blockchain consensus algorithms, reviews blockchain applications and discusses technical challenges as well as recent advances in tackling the challenges. Moreover, this paper also points out the future directions in the blockchain technology.
The usage of process choreographies and decentralized Business Process Management Systems has been named as an alternative to centralized business process orchestration. In choreographies, control over a process instance is shared between independent parties, and no party has full control or knowledge during process runtime. Nevertheless, it is necessary to monitor and verify process instances during runtime for purposes of documentation, accounting, or compensation.
To achieve business process runtime verification, this work explores the suitability of the Bitcoin blockchain to create a novel solution for choreographies. The resulting approach is realized in a fully-functional software prototype. This software solution is evaluated in a qualitative comparison. Findings show that our blockchain-based approach enables a seamless execution monitoring and verification of choreographies, while at the same time preserving anonymity and independence of the process participants. Furthermore, the prototype is evaluated in a performance analysis
(Note that we have updated the paper to the accepted version on 23 Jan 2018)
Blockchain technology offers a sizable promise to rethink the way inter-organizational
business processes are managed because of its potential to realize execution with-
out a central party serving as a single point of trust (and failure). To stimulate
research on this promise and the limits thereof, in this paper we outline the
challenges and opportunities of blockchain for Business Process Management
(BPM). We structure our commentary alongside two established frameworks,
namely the six BPM core capabilities and the BPM lifecycle, and detail seven
research directions for investigating the application of blockchain technology to
BPM.
Blockchain technology enables the execution of collaborative business processes involving mutually untrusted parties. Existing tools allow such processes to be modeled using high-level notations and compiled into smart contracts that can be deployed on blockchain platforms. However, these tools brush aside the question of who is allowed to execute which tasks in the process, either by deferring the question altogether or by adopting a static approach where all actors are bound to roles upon process instantiation. Yet, a key advantage of blockchains is their ability to support dynamic sets of actors. This paper presents a model for dynamic binding of actors to roles in collaborative processes and an associated binding policy specification language. The proposed language is endowed with a Petri net semantics, thus enabling policy consistency verification. The paper also outlines an approach to compile policy specifications into smart contracts for enforcement. An experimental evaluation shows that the cost of policy enforcement increases linearly with the number of roles and constraints.
Blockchain platforms, such as Ethereum, allow a set of actors to maintain a ledger of transactions without relying on a central authority and to deploy programs, called smart contracts, that are executed whenever certain transactions occur. These features can be used as basic building blocks for executing collaborative business processes between mutually untrusting parties. However, implementing business processes using the low‐level primitives provided by blockchain platforms is cumbersome and error‐prone. In contrast, established business process management systems (BPMSs), such as those based on the standard Business Process Model and Notation (BPMN), provide convenient abstractions for rapid development of process‐oriented applications. This article demonstrates how to combine the advantages of a BPMS with those of a blockchain platform. The article introduces a blockchain‐based BPMN execution engine, named Caterpillar. Like any BPMN execution engine, Caterpillar supports the creation of instances of a process model and allows users to monitor the state of process instances and to execute tasks thereof. The specificity of Caterpillar is that the state of each process instance is maintained on the (Ethereum) blockchain and the workflow routing is performed by smart contracts generated by a BPMN‐to‐Solidity compiler. The Caterpillar compiler supports a large array of BPMN constructs, including subprocesses, multiple‐instance activities, and event handlers. The paper describes the architecture of Caterpillar and the interfaces it provides to support the monitoring of process instances, the allocation and execution of work items, and the execution of service tasks.
A workflow (WF) is a formal description of a business process in which single atomic work units (tasks), organized in a partial order, are assigned to processing entities (agents) in order to achieve some business goal(s). A workflow management system must coordinate the execution of tasks and WF instances. Usually, the assignment of tasks to agents is accomplished by external constraints not represented in a WF. An access-controlled workflow (ACWF) extends a classical WF by explicitly representing agent availability for each task and authorization constraint. Authorization constraints model which users are authorized for which tasks depending on “who did what”. Recent research has addressed temporal controllability of WFs under conditional and temporal uncertainty. However, controllability analysis for ACWFs under conditional uncertainty has never been addressed before. In this paper, we define weak, strong and dynamic controllability of ACWFs under conditional uncertainty, we present algorithmic approaches to address each of these types of controllability, and we synthesize execution strategies that specify which user has been (or will be) assigned to which task.