Modeling and Managing Interactions among Business Processes

Most workflow management systems (WfMSs) only support the separate andindependent execution of business processes. However, processes often needto interact with each other, in order to synchronize the execution of theiractivities, to exchange process data, to request execution of services, orto notify progresses in process execution. Recent market trends also raisethe need for cooperation and interaction between processes executed in differentorganizations, posing additional challenges. In fact, in order to reduce costsand provide better services, companies are pushed to increase cooperation and toform virtual enterprises, where business processes span across organizationalboundaries and are composed of cooperating workflows executed in differentorganizations. Workflow interaction in a cross-organizational environment iscomplicated by the heterogeneity of workflow management platforms on top ofwhich workflows are defined and executed and by the different and possiblycompeting business policies and business goals that drive process executionin each organization.In this paper we propose a model and system that enable interactionbetween workflows executed in the same or in different organizations. Weextend traditional workflow models by allowing workflows to publish andsubscribe to events, and by enabling the definition of points in the processexecution where events should be sent or received. Event notifications aremanaged by a suitable event service that is capable of filtering andcorrelating events, and of dispatching them to the appropriate targetworkflow instances. The extended model can be easily mapped onto anyworkflow model, since event specific constructs can be specified by means ofordinary workflow activities, for which we provide the implementation. Inaddition, the event service is easily portable to different platforms, anddoes not require integration with the WfMS that supports the cooperatingworkflows. Therefore, the proposed approach is applicable in virtually anyenvironment and is independent on the specific platform adopted     

WIRES: A Methodology for Developing Workflow Applications

Workflow management systems are becoming a relevant support for a large class of business applications, and many workflow models as well as commercial products are currently available. While the large availability of tools facilitates the development and the fulfilment of customer requirements, workflow application development still requires methodological guidelines that drive the developers in the complex task of rapidly producing effective applications. In fact, it is necessary to identify and model the business processes, to design the interfaces towards existing cooperating systems, and to manage implementation aspects in an integrated way. This paper presents the WIRES methodology for developing workflow applications under a uniform modelling paradigm – UML modelling tools with some extensions – that covers all the life cycle of these applications: from conceptual analysis to implementation. High-level analysis is performed under different perspectives, including a business and an organisational perspective. Distribution, interoperability and cooperation with external information systems are considered in this early stage. A set of “workflowability” criteria is provided in order to identify which candidate processes are suited to be implemented as workflows. Non-functional requirements receive particular emphasis in that they are among the most important criteria for deciding whether workflow technology can be actually useful for implementing the business process at hand. The design phase tackles aspects of concurrency and cooperation, distributed transactions and exception handling. Reuse of component workflows, available in a repository as workflow fragments, is a distinguishing feature of the method. Implementation aspects are presented in terms of rules that guide in the selection of a commercial workflow management system suitable for supporting the designed processes, coupled with guidelines for mapping the designed workflows onto the model offered by the selected system.     

一种基于关系型数据库的工作流管理系统

本文提出了一种基于关系型数据库的工作流管理系统。该方案将业务分为基础业务与拓展业务,然后通过一个简单的工作流模型表示基础业务逻辑,并使用关系型数据库处理拓展业务。此外,该方案将业务逻辑与业务的设计相结合,形成了一个通过配置即可开发信息管理系统的平台。该系统的实际应用表明该方案实现简单,能够处理大部分其他工作流模型无法表示的工作流模式,并且该系统易于业务人员操作,能够达到快速开发的目的。     

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.     

Development of context-aware workflow systems based on Petri Net Markup Language

The Petri Net Markup Language (PNML) is originally an XML-based interchange format for Petri nets. Individual companies may specify their process models in Petri nets and exchange the Petri nets with other companies in PNML. This paper aims to demonstrate the capabilities of PNML in the development of applications instead of an industrial interchange format only. In this paper, we apply PNML to develop context-aware workflow systems. In existing literature, different methodologies for the design of context-aware systems have been proposed. However, workflow models have not been considered in these methodologies. Our interests in this paper are to propose a methodology to automatically generate context-aware action lists for users and effectively control resource allocation based on the state of the workflow systems. To achieve these objectives, we first propose Petri net models to describe the workflows. Next, we propose models to capture resource activities. Finally, the interactions between workflows and resources are combined to obtain a model for the whole processes. Based on the combined model, we propose architecture to automatically generate context-aware graphical user interface to guide the users and control resource allocation in workflow systems. We demonstrate our design methodology using a health care example.     

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.     

Context-aware workflow management for virtual enterprises based on coordination of agents

Although virtual enterprises (VE) make it possible for small flexible enterprises to form a collaborative network to respond to business opportunities through dynamic coalition and sharing of the core competencies and resources, they also pose new challenges and issues. Creation of VE involves dynamically established partnerships between the partners and relies on a flexible coordination scheme. The dynamic organizations formed in VE present a challenge in the development of a new methodology to dynamically allocate re-sources and deliver the relevant information to the right people at the right time. A key issue is the development of an effective workflow management scheme for VE. Multi-agent systems (MAS) provide a flexible architecture to deal with changes based on dynamic organization and collaboration of autonomous agents. Despite the extensive studies and research results on MAS, development of a design methodology to support coordination and operations is critical to the success and adoption of VE. The objectives of this research are to propose a design methodology to facilitate coordination and development of context-aware workflow management systems and achieve effective resource allocation for VE based on MAS architecture. To achieve these objectives, a scheme for coordination of agents is proposed. Petri net models are used in the coordination scheme to describe workflows and capture resource activities in VE. The interactions between agents lead to a dynamic workflow model for VE. Based on the aforementioned model, we propose architecture to dynamically generate context-aware graphical user interface to guide the users and control resource allocation based on the state of VE. An order management example is used throughout this paper to illustrate the proposed design methodology.     

工作流模型挖掘算法及其应用研究

工作流管理系统由工作流模型所驱动,但产业界的实践表明定义工作流模型的工作不仅费时而且易错。工作流挖掘技术能够帮助解决这一问题,并能为现有工作流的分析与优化提供参考。简要介绍三种典型且具有应用价值的工作流模型挖掘算法,并应用其中一种挖掘算法,详细讨论了一个实际的工作流模型挖掘过程。挖掘过程以某Staffware系统的工作流日志文件为起点,包括数据预处理、初始工作流模型挖掘、初始工作流模型化简三个主要步骤,具体实现可通过一个工作流模型挖掘子系统参与完成。     

Adding flexibility to workflows through incremental planning

Workflow management systems usually interpret a workflow definition rigidly. However, there are real life situations where users should be allowed to deviate from the prescribed static workflow definition for various reasons, including lack of information, unavailability of the required resources and unanticipated situations. Furthermore, workflow complexity may grow exponentially if all possible combinations of anticipated scenarios must be compiled into the workflow definition. To flexibilize workflow execution and help reduce workflow complexity, this paper proposes a dual strategy that combines a library of predefined typical workflows with a planner mechanism capable of incrementally synthesizing new workflows, at execution time. This dual strategy is motivated by the difficulty of designing emergency plans, modeled as workflows, which account for real-life complex crisis or accident scenarios.     

The OCoN Approach to Workflow Modeling in Object-Oriented Systems

Workflow management aims at modeling and executing application processes in complex technical and organizational environments. Modern information systems are often based on object-oriented design techniques, for instance, the Unified Modeling Language (UML). These systems consist of application objects which collaborate to achieve a common goal. Although application objects collaborate in the context of business processes that can be supported by workflow technology, workflow modeling is typically done with proprietary workflow languages. Hence, two separate formalisms are present for modeling application objects and workflows. In this paper we try to remedy this situation by proposing the use of Object Coordination Nets (OCoN) for workflow modeling. OCoN nets provide a seamless integration with UML structure diagrams. The OCoN formalism also helps to deal with all relevant aspects of modeling complex workflow systems in a scalable and consistent manner.     

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.     

基于对象的角色工作流模型研究

工作流是流程集成的有效方法，但工作流模型在描述复杂的流程时语义和柔性不足，导致实用中工作流模型的仿真分析和运行能力欠佳；另一方面，对象技术作为一种很有潜力的流程建模方法，可以改善工作流的描述。它与工作流的结合，将有助于上述问题的解决。文章借助对象技术，分析了面向角色的工作流模型，并在此基础上讨论了其实现。     

Translating relational schema into XML schema definition with data semantic preservation and XSD graph

Many legacy systems have been created by using relational database operating not for the Internet expression. Since the relational database is not an efficient way for data explosion, electronic transfer of data, and electronic business on the Web, we introduce a methodology in which a relational schema will be translated to an Extensible Markup Language (XML) schema definition for creating an XML database that is a simple and efficient format on the Web. We apply the Indirect Schema Translation Method that is a semantic-based methodology in this project. The mechanism is that the Relational Schema will be translated into the conceptual model, an Extended Entity Relationship (EER) Model using Reverse Engineering. Afterward, the EER model will be mapped to an XML Schema Definition Language (XSD) Graph as an XML conceptual schema using Semantic Transformation. Finally, the XSD Graph will be mapped into the XSD as an XML logical schema in the process of Forward Engineering, and the data semantics of participation, cardinality, generalization, aggregation, categorization, N-ary and U-ary relationship are preserved in the translated XML schema definition.     

Protecting the consistency of workflow applications in collaborative development environments

Collaborative development environments allow a group of users to view and edit a shared item from geographically dispersed sites. Consistency maintenance in the face of concurrent accesses to shared entities is one of the core issues in the design of these systems. The paper introduces a lock based solution and three different algorithms that enable controlled, concurrent access to workflows for multiple application developers. Collaborative development of workflow applications promises better outcome in shorter time. The described method ensures that collaborators cannot break the consistency criteria of workflows by adding cycles or invalid edges to the graphs. A formal analysis of the three graph locking algorithms is also provided, focusing on the number of users who are allowed to edit a single workflow simultaneously. Based on the findings, a more powerful fourth graph locking algorithm is defined.     

基于关系数据库的工作流服务器设计与实现

工作流服务器负责解释执行工作流定义。基于关系数据库构建工作流服务器,利用关系结构描述工作流数据模型,利用存储过程实现工作流业务逻辑,使工作流服务器和数据库服务器融为一体,不需开发专门的工作流定义语言和相应的语言解析器。和传统的工作流服务器相比,它是用位于服务器内部的存储过程处理工作流应用数据,而不是通过调用外部应用程序来处理,因此也简化了服务器接口实现。此工作流服务器由工作流引擎、消息管理子系统和目录服务子系统组成。     

Designing secure databases

Security is an important issue that must be considered as a fundamental requirement in information systems development, and particularly in database design. Therefore security, as a further quality property of software, must be tackled at all stages of the development. The most extended secure database model is the multilevel model, which permits the classification of information according to its confidentiality, and considers mandatory access control. Nevertheless, the problem is that no database design methodologies that consider security (and therefore secure database models) across the entire life cycle, particularly at the earliest stages currently exist. Therefore it is not possible to design secure databases appropriately. Our aim is to solve this problem by proposing a methodology for the design of secure databases. In addition to this methodology, we have defined some models that allow us to include security information in the database model, and a constraint language to define security constraints. As a result, we can specify a fine-grained classification of the information, defining with a high degree of accuracy which properties each user has to own in order to be able to access each piece of information. The methodology consists of four stages: requirements gathering; database analysis; multilevel relational logical design; and specific logical design. The first three stages define activities to analyze and design a secure database, thus producing a general secure database model. The last stage is made up of activities that adapt the general secure data model to one of the most popular secure database management systems: Oracle9i Label Security. This methodology has been used in a genuine case by the Data Processing Center of Provincial Government. In order to support the methodology, we have implemented an extension of Rational Rose, including and managing security information and constraints in the first stages of the methodology.     

A meta modeling approach to workflow management systems supporting exception handling

Workflow Management Systems (WFMSs) facilitate the definition of structure and decomposition of business processes and assists in management of coordinating, scheduling, executing and monitoring of such activities. Most of the current WFMSs are built on traditional relational database systems and/or using an object-oriented database system for storing the definition and run time data about the workflows. However, a WFMS requires advanced modeling functionalities to support adaptive features, such as on-line exception handling. This article describes our advanced meta-modeling approach using various enabling technologies (such as object orientation, roles, rules, active capabilities) supported by an integrated environment, the ADOME, as a solid basis for a flexible WFMS involving dynamic match making, migrating workflows and exception handling.     

A case study in systematic hypermedia design

Hypermedia structuring and navigation requires design methodologies different from those developed for standard information systems. This case study details our successful application of relationship management methodology (RMM), a hypermedia systems analysis and design methodology, to ACM SIGLINK's LINKBase. LINKBase is a World Wide Web (WWW) application, which dynamically generates WWW pages from a relational database containing information about hypermedia-related events such as conferences, publications, authors, and sponsoring organizations. We describe our experience applying RMM in this case study, summarize design lessons we learned in the process, present extensions to RMM, discuss human–computer interaction (HCI) aspects of RMM, and ground our work in the hypermedia design and HCI literature. Our experiences should encourage hypermedia and WWW developers to utilize systematic design techniques to build highly usable and useful WWW applications.     

A characterization of workflow management systems for extreme-scale applications

Automation of the execution of computational tasks is at the heart of improving scientific productivity. Over the last years, scientific workflows have been established as an important abstraction that captures data processing and computation of large and complex scientific applications. By allowing scientists to model and express entire data processing steps and their dependencies, workflow management systems relieve scientists from the details of an application and manage its execution on a computational infrastructure. As the resource requirements of today’s computational and data science applications that process vast amounts of data keep increasing, there is a compelling case for a new generation of advances in high-performance computing, commonly termed as extreme-scale computing, which will bring forth multiple challenges for the design of workflow applications and management systems. This paper presents a novel characterization of workflow management systems using features commonly associated with extreme-scale computing applications. We classify 15 popular workflow management systems in terms of workflow execution models, heterogeneous computing environments, and data access methods. The paper also surveys workflow applications and identifies gaps for future research on the road to extreme-scale workflows and management systems.