From Contracts to E-Contracts: Modeling and Enactment

Contracts are complex to understand, represent and process electronically. Usually, contracts involve various entities such as parties, activities and clauses. An e-contract is a contract modeled, specified, executed and enacted (controlled and monitored) by a software system (such as a workflow system). Workflows are used to automate business processes that govern adherence to the e-contracts. E-contracts can be mapped to inter-related workflows, which have to be specified carefully to satisfy the contract requirements. Most workflow models do not have the capabilities to handle complex inter/intra relationships among entities in e-contracts. An e-contract does not adhere to activity/task oriented workflow processes, thus generating a gap between a conceptual model of e-contract and workflow. In this paper, we describe conceptual modeling of e-contracts and present a business process model for e-contract enactment. The enactment of e-contracts necessitates dynamic generation and initiation of workflows during the e-contract execution, besides the static workflows. ER^EC business process model facilitates an integrated approach to e-contracts enactment. Our methodology is illustrated by means of a case study conducted using Financial Messaging Solution contract for banking transactions.     

Petri net-based process monitoring: a workflow management system for process modelling and monitoring

Nowadays business process management is becoming a fundamental piece of many industrial processes. To manage the evolution and interactions between the business actions it is important to accurately model the steps to follow and the resources needed by a process. Workflows provide a way of describing the order of execution and the dependencies between the constituting activities of business processes. Workflow monitoring can help to improve and avoid delays in industrial environments where concurrent processes are carried out. In this article a new Petri net extension for modelling workflow activities together with their required resources is presented: resource-aware Petri nets (RAPN). An intelligent workflow management system for process monitoring and delay prediction is also introduced. Resource aware-Petri nets include time and resources within the classical Petri net workflow representation, facilitating the task of modelling and monitoring workflows. The workflow management system monitors the execution of workflows and detects possible delays using RAPN. In order to test this new approach, different services from a medical maintenance environment have been modelled and simulated.     

A layered architecture for flexible Web service invocation

Web service composition is emerging as an interesting approach to integrate business applications and create intra‐organizational business processes. Single Web services are combined to create a complex Web service that will realize the process business logic. Once the process is created, it is executed by an orchestration engine that invokes individual Web services in the correct order. However, Web services composing the workflow sometimes become unavailable during the run‐time phase, blocking process execution. This paper describes an architecture that allows the flexible orchestration of business processes. With this approach, Web services composing the process can be automatically substituted with other compatible Web services during process execution. A methodology is defined to evaluate Web service compatibility based on interface matching, in order to select substitutable Web services. Copyright © 2005 John Wiley & Sons, Ltd.     

Caterpillar: A business process execution engine on the Ethereum blockchain

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.     

面向服务集成的工作流模型及其实现方法

针对现有工作流系统集成已有软件服务时存在的两个问题:1)对于业务流程中所集成服务的描述信息不足,无法满足服务集成需要;2)流程定制时可选择节点类型少,节点不具有业务含义,导致其定制过程复杂;提出一种新的工作流模型。首先,通过分析服务集成环境下的实际业务流程确定了模型的三部分信息:结构信息、服务信息和人员信息;其次,将模型中各部分信息与JPDL作了对应说明,表明了模型的完备性;最后,详细介绍了三部分信息的关键要素。实验结果表明,基于35种服务可以快速搭建出满足实际业务需求的48种业务流程。模型中丰富的服务信息为流程运行提供了保障,流程运行正确率100%;流程定制更加简便快捷,流程从定制到运行平均时间小于2 min。通过该模型可以快速地基于已有服务构建新的业务流程,降低了为新需求开发软件的成本。     

Service-oriented smart home applications: composition, code generation, deployment, and execution

A smart home usually has a variety of devices or home appliance, instead of designing software for a specific home, this paper proposes a service-oriented framework with a set of ontology systems to support service and device publishing, discovery of devices and their services, composition of control software using existing control services that wrap devices, deployment, and execution of the composed service in an computing environment, monitoring the execution, and recovery from device failure. The ontology systems specify semantic information about devices, services, and workflows used in various smart home, and users can compose and recompose services for their specific needs. New devices, workflows, and services can be added into ontology. Most of the steps in this process can be automated including code generation. For example, service composition will be carried out in three steps: abstract workflow design, function construction, and device discovery, and different codes can be generated for different computing platforms such as Java and Open Services Gateway initiative environments. In this way, a variety of smart home can be constructed rapidly using the framework by discovery and composition using existing services and workflows. This paper illustrates this framework using a media control example to illustrate the ontology, discovery, composition, deployment, execution, monitoring, and recovery.     

Toward an execution system for self-healing workflows in cyber-physical systems

Cyber-physical systems (CPS) represent a new class of information system that also takes real-world data and effects into account. Software-controlled sensors, actuators and smart objects enable a close coupling of the cyber and physical worlds. Introducing processes into CPS to automate repetitive tasks promises advantages regarding resource utilization and flexibility of control systems for smart spaces. However, process execution systems face new challenges when being adapted for process execution in CPS: the automated processing of sensor events and data, the dynamic invocation of services, the integration of human interaction, and the synchronization of the cyber and physical worlds. Current workflow engines fulfill these requirements only to a certain degree. In this work, we present PROtEUS—an integrated system for process execution in CPS. PROtEUS integrates components for event processing, data routing, dynamic service selection and human interaction on the modeling and execution level. It is the basis for executing self-healing model-based workflows in CPS. We demonstrate the applicability of PROtEUS within two case studies from the Smart Home domain and discuss its feasibility for introducing workflows into cyber-physical systems.     

CA-PLAN,a service-oriented workflow

Workflow management systems (WfMSs) are accepted worldwide due to their ability to model and control business processes. Previously, we defined an intra-organizational workflow specification model, Process LANguage (PLAN). PLAN, with associated tools, allowed a user to describe a graph specification for processes, artifacts, and participants in an organization. PLAN has been successfully implemented in Agentflow to support workflow (Agentflow) applications. PLAN, and most current WfMSs are designed to adopt a centralized architecture so that they can be applied to a single organization. However, in such a structure, participants in Agentflow applications in different organizations cannot serve each other with workflows. In this paper, a service-oriented cooperative workflow model, Cooperative Agentflow Process LANguage (CA-PLAN) is presented. CA-PLAN proposes a workflow component model to model inter-organizational processes. In CA-PLAN, an inter-organizational process is partitioned into several intra-organizational processes. Each workflow system inside an organization is modeled as an Integrated Workflow Component (IWC). Each IWC contains a process service interface, specifying process services provided by an organization, in conjunction with a remote process interface specifying what remote processes are used to refer to remote process services provided by other organizations, and intra-organizational processes. An IWC is a workflow node and participant. An inter-organizational process is made up of connections among these process services and remote processes with respect to different IWCs. In this paper, the related service techniques and supporting tools provided in Agentflow systems are presented.     

A decentralized execution model for inter-organizational workflows

Workflow Management Systems (WFMS) are often used to support the automated execution of business processes. In today’s networked environment, it is not uncommon for organizations representing different business partners to collaborate for providing value-added services and products. As such, workflows representing the business processes in this loosely-coupled, dynamic and ad hoc coalition environment tend to span across the organizational boundaries. As a result, it is not viable to employ a single centralized WFMS to control the execution of the inter-organizational workflow due to limited scalability, availability and performance. To this end, in this paper, we present a decentralized workflow model, where inter-task dependencies are enforced without requiring to have a centralized WFMS. In our model, a workflow is divided into partitions called self-describing workflows, and handled by a light weight workflow management component, called the workflow stub, located at each organization. We present a performance study by considering different types of workflows with varying degrees of parallelism. Our performance results indicate that decentralized workflow management indeed enjoys significant gain in performance over its centralized counterpart in cases where there is less parallelism. The work of V. Atluri is supported in part by the National Science Foundation under grant IIS-0306838.     

基于语义描述的Web服务工作流集成

Web服务是可以由其它软件在Internet上访问的一种软件接口。Web服务工作流则是一组按一定顺序执行的Web服务的集合。如何集成一个Web服务工作流,特别是如何运用对Web服务的语义描述来为一个工作流来自动寻找和匹配Web服务,这是目前所急需解决的问题。介绍如何用语义Web服务本体论来集成工作流,同时提出一个基于语义Web服务工作流集成的模型。     

Organizational Management in Workflow Applications – Issues and Perspectives

Business processes automation requires the specification of process structures as well as the definition of resources involved in the execution of these processes. While the modeling of business processes and workflows is well researched, the link between the organizational elements and process activities is less well understood, and current developments in the web services choreography area completely neglect the organizational aspect of workflow applications. The purpose of this paper is to give an overview of the organizational aspects of workflow technology in the context of the workflow life cycle, to provide a review of existing work, and to develop guidelines for the design of a workflow-enabled organization, which can be used by both workflow vendors and users.     

基于服务网格的制造资源集成

提出了一种基于服务网格的制造资源集成方法，通过将服务网格技术引入制造行业，实现了制造资源的虚拟化，为制造资源提供了统一的接口和互操作协议、屏蔽平台及所使用技术的异构性。平台采用基于服务的协同工作流技术，在动态变化的环境中，能够根据用户需求优化业务逻辑及其执行过程，选择、配置和调度相应的制造资源完成指定的任务，实现跨组织的资源共享和任务协同。     

Workflow Requirements Modelling Using XML

When modelling inter-organisational workflow it is important not to make assumptions such as with regard to the formats of the data exchanged between the workflow participants or the technical infrastructures and platforms, as they can restrict the range of possible workflow management implementations. The approach presented in this paper allows for the conceptual modelling of workflow processes using primitive constructs such as nodes, rules and business documents. The paper presents both a graphical notation for modelling workflows as well as a mapping of the workflow constructs to XML models that follows the Workflow Management Coalition interoperability standards. This allows the modelled workflow to be interpreted and executed by a variety of workflow engines.     

Event correlation for process discovery from web service interaction logs

Understanding, analyzing, and ultimately improving business processes is a goal of enterprises today. These tasks are challenging as business processes in modern enterprises are implemented over several applications and Web services, and the information about process execution is scattered across several data sources. Understanding modern business processes entails identifying the correlation between events in data sources in the context of business processes (event correlation is the process of finding relationships between events that belong to the same process execution instance). In this paper, we investigate the problem of event correlation for business processes that are realized through the interactions of a set of Web services. We identify various ways in which process-related events could be correlated as well as investigate the problem of discovering event correlation (semi-) automatically from service interaction logs. We introduce the concept of process view to represent the process resulting from a certain way of event correlation and that of process space referring to the set of possible process views over process events. Event correlation is a challenging problem as there are various ways in which process events could be correlated, and in many cases, it is subjective. Exploring all the possibilities of correlations is computationally expensive, and only some of the correlated event sets result in process views that are interesting. We propose efficient algorithms and heuristics to identify correlated event sets that lead potentially to interesting process views. To account for its subjectivity, we have designed the event correlation discovery process to be interactive and enable users to guide it toward process views of their interest and organize the discovered process views into a process map that allows users to effectively navigate through the process space and identify the ones of interest. We report on experiments performed on both synthetic and real-world datasets that show the viability and efficiency of the approach.     

Social workflows—Vision and potential study

Social workflows pervade peoples׳ everyday life. Whenever a group of persons works together on a challenging or multifaceted task, a social workflow begins. Unlike traditional business workflows, such social workflows aim at supporting processes that contain personal tasks and data. In this work, we envision a social workflow service as part of a social network that enables private individuals to construct social workflows according to their specific needs and to keep track of the workflow execution. The proposed features for a social workflow service could help individuals to accomplish their private goals. The presented idea is contrasted with established research areas and applications to show the degree of novelty of this work. It is shown how novel ideas for knowledge management, facilitated by a process-oriented case-based reasoning approach, support private individuals and how they can obtain an appropriate social workflow through sharing and reuse of respective experience. Two empirical studies confirm the potential benefits of a social workflow service in general and the core features of the developed concept.     

Constructing scalable Internet of Things services based on their event‐driven models

Even though many IoT (Internet of Things) applications have been implemented based on distributed events, how to construct scalable IoT services is still unclear. In this paper, we first discuss representing physical entities as IoT resources in the cyber world and integrate them into IoT services and then use an event session mechanism to express the coordination logic in an IoT service system. Given their event‐driven models, the scalable IoT services are constructed through decoupling one service at behavior from others, where running atomic service instances with high concurrency is our first focus, and distributed execution of an IoT business process is our second focus. Our last focus is to make each distributed business process execution unit hold its properties in the whole process, which requires modeling the environment as a prerequisite to compute its properties, and some assume‐guarantee rules for composing the services from the environment's perspective. We then propose a platform to support the construction, where according to the behavior decoupling features, one IoT business process is decomposed into pieces of event composition logic and business computation logic, together with separating the data dependency of computation functions in each process fragment, such that it can be concurrently executed and distributed. A practical application is implemented to concept‐prove our work. Copyright © 2015 John Wiley & Sons, Ltd.     

Quality of service for workflows and web service processes

Workflow management systems (WfMSs) have been used to support various types of business processes for more than a decade now. In workflows or Web processes for e-commerce and Web service applications, suppliers and customers define a binding agreement or contract between the two parties, specifying quality of service (QoS) items such as products or services to be delivered, deadlines, quality of products, and cost of services. The management of QoS metrics directly impacts the success of organizations participating in e-commerce. Therefore, when services or products are created or managed using workflows or Web processes, the underlying workflow engine must accept the specifications and be able to estimate, monitor, and control the QoS rendered to customers. In this paper, we present a predictive QoS model that makes it possible to compute the quality of service for workflows automatically based on atomic task QoS attributes. We also present the implementation of our QoS model for the METEOR workflow system. We describe the components that have been changed or added, and discuss how they interact to enable the management of QoS.     

Process interoperability in healthcare systems with dynamic semantic web services

Healthcare systems are very complex due to extreme heterogeneity in their data and processes. Researchers and practitioner need to make systems interoperable and integrate for the benefit of all the stakeholders including hospitals, clinicians, medical support staff, and patients. The broader goal of interoperability can only be achieved when standards are practiced.Two different healthcare systems can earn HL7 conformance and compliance but at the same time can be incompatible for interoperability because of varying implementation of HL7 interaction model. This is mainly because workflows in healthcare systems are very complex. Interoperability on one hand requires flexible mechanism for the mapping of business processes to a standard, HL7 in our example. On the other hand it requires deeper understanding of the standard interaction model and gaps created by their incompatible implementations. In this paper we propose a novel technique of dynamically creating semantic web services as overlay on top of the existing services. We used Web Service Modeling Framework as an underlying architecture for HL7 process artifacts implementation as semantic web services. These semantic services are mapped to our proposed interaction ontology. Integrated reasoning mechanism provides necessary execution semantics for more effective and seamless end-to-end communication.The prototype we tested on different processes from the laboratory domain at a local diagnostic laboratory with uninterrupted process flow. The scenario of Result Query Placer interaction flow and its associated process artifacts are executed for the proof of concept.The proposed solution complements the existing data interoperability in HL7 and leads to semantic process interoperability. The achievement of semantic interoperability results in timely delivery of healthcare services to patients saving precious lives.     

Structured design,consistency analysis and failure reasoning of business workflows with activity-control templates and causal ordering

The design, analysis, control and diagnosis of business workflows have been major challenges for enterprise information system designers. We propose a structured framework for workflow design, formal semantics, consistency analysis, execution automation and failure reasoning targeting E-commerce applications. A business workflow is modeled by using a visual tool named activity-control (AC) diagram. Frequently occurring business procedures are captured by the adoptions of reusable AC templates. With formally defined semantics by a combination of first-order logic and happen-before causal ordering in distributed system theory, workflow consistency can be mechanically analyzed at design time while failure reasoning can be applied at execution time for problem diagnosis. A completely specified model is automatically converted to a workflow by an iterative traversal algorithm that maps an AC diagram to an XML workflow specification which can then be executed automatically by an XML workflow engine. A failure reasoning and diagnosis algorithm is devised to find all possible causes of a failed execution when problems occur. Preliminary proof-of-concept implementation and evaluation results demonstrate the feasibility and effectiveness of our framework and techniques.