Modelling work distribution mechanisms using Colored Petri Nets

Workflow management systems support business processes and are driven by their models. These models cover different perspectives including the control-flow, resource, and data perspectives. This paper focuses on the resource perspective, i.e., the way the system distributes work based on the structure of the organization and capabilities/qualifications of people. Contemporary workflow management systems offer a wide variety of mechanisms to support the resource perspective. Because the resource perspective is essential for the applicability of such systems, it is important to better understand the mechanisms and their interactions. Our goal is not to evaluate and compare what different systems do, but to understand how they do it. We use Colored Petri Nets (CPNs) to model work distribution mechanisms. First, we provide a basic model that can be seen as a reference model of existing workflow management systems. This model is then extended for three specific systems (Staffware, FileNet, and FLOWer). Moreover, we show how more advanced work distribution mechanisms, referred to as resource patterns, can be modelled and analyzed.     

SEAM: A state-entity-activity-model for a well-defined workflowdevelopment methodology

Current conceptual workflow models use either informally defined conceptual models or several formally defined conceptual models that capture different aspects of the workflow, e.g., the data, process, and organizational aspects of the workflow. To the best of our knowledge, there are no algorithms that can amalgamate these models to yield a single view of reality. A fragmented conceptual view is useful for systems analysis and documentation. However, it fails to realize the potential of conceptual models to provide a convenient interface to automate the design and management of workflows. First, as a step toward accomplishing this objective, we propose SEAM (State-Entity-Activity-Model), a conceptual workflow model defined in terms of set theory. Second, no attempt has been made, to the best of our knowledge, to incorporate time into a conceptual workflow model. SEAM incorporates the temporal aspect of workflows. Third, we apply SEAM to a real-life organizational unit's workflows. In this work, we show a subset of the workflows modeled for this organization using SEAM. We also demonstrate, via a prototype application, how the SEAM schema can be implemented on a relational database management system. We present the lessons we learned about the advantages obtained for the organization and, for developers who choose to use SEAM, we also present potential pitfalls in using the SEAM methodology to build workflow systems on relational platforms. The information contained in this work is sufficient enough to allow application developers to utilize SEAM as a methodology to analyze, design, and construct workflow applications on current relational database management systems. The definition of SEAM as a context-free grammar, definition of its semantics, and its mapping to relational platforms should be sufficient also, to allow the construction of an automated workflow design and construction tool with SEAM as the user interface     

基于J2EE的工作流管理系统模型

本文在分析了传统企业管理信息系统的局限性和采用工作流技术带来改变的基础上,讨论了工作流的基本概念,并根据工作流参考模型提出了一种基于J2EE架构的工作流管理系统模型,同时介绍了该系统模型的特点和应用。     

Inheritance of workflows: an approach to tackling problems related to change

Inheritance is one of the key issues of object-orientation. The inheritance mechanism allows for the definition of a subclass which inherits the features of a specific superclass. When adapting a workflow process definition to specific needs (ad-hoc change) or changing the structure of the workflow process as a result of reengineering efforts (evolutionary change), inheritance concepts are useful to check whether the new workflow process inherits some desirable properties of the old workflow process. Today's workflow management systems have problems dealing with both ad-hoc changes and evolutionary changes. As a result, a workflow management system is not used to support dynamically changing workflow processes or the workflow processes are supported in a rigid manner, i.e., changes are not allowed or handled outside of the workflow management system. In this paper, we propose inheritance-preserving transformation rules for workflow processes and show that these rules can be used to avoid problems such as the “dynamic-change bug.” The dynamic-change bug refers to errors introduced by migrating a case (i.e., a process instance) from an old process definition to a new one. A transfer from an old process to a new process can lead to duplication of work, skipping of tasks, deadlocks, and livelocks. Restricting change to the inheritance-preserving transformation rules guarantees transfers without any of these problems. Moreover, the transformation rules can also be used to extract aggregate management information in case more than one version of a workflow process cannot be avoided.     

The design of a JADE-based autonomous workflow management system for collaborative SoC design

Given a fast changing electronics goods marketplace, designers of integrated circuits and components need to be more competitive, efficient, flexible, and use collaborative workflow to reduce time-to-market and a project’s life cycle. In recent years, agent-based workflow management systems (WfMS) have been widely used to monitor and control business design processes. In this paper, intelligent agents are applied to the collaborative system-on-chip (SoC) design environment. The proposed JADE-based autonomous workflow management system (JAWMS) uses a workflow coordination mechanism and an agent integration mechanism to enable the analysis, management and interaction of automated design processes. The workflow coordination mechanism uses five domain specific agents to perform the workflow enactment services and a generic agent to control the system flow logic. The system kernel of JAWMS follows the specifications of the workflow reference model provided by the workflow management coalition (WfMC). The agent integration mechanism supports an agent to interact with other JADE-based agent platforms and to coordinate and monitor workflow coordination messages. All agents are written in the Java language using the JADE platform and work together to perform flexible, adaptive and dynamic design tasks in an autonomous and collaborative way. JAWMS facilitates SoC design and team interaction in a collaborative but distributed product development environment.     

Applying Propositional Logic to Workflow Verification

The increasing complexity of business processes in the era of e-business has heightened the need for workflow verification tools. However, workflow verification remains an open and challenging research area. As an indication, most of commercial workflow management systems do not yet provide workflow designers with formal workflow verification tools. We propose a logic-based verification method that is based on a well-known formalism, i.e., propositional logic. Our logic-based workflow verification approach has distinct advantages such as its rigorous yet simplistic logical formalism and its ability to handle generic activity-based process models. In this paper, we present the theoretical framework for applying propositional logic to workflow verification and demonstrate that logic-based workflow verification is capable of detecting process anomalies in workflow models.     

Workflow evolution

A basic step towards flexibility in workflow systems is the consistent and effective management of workflow evolution, i.e. of changing existing workflows while they are operational. One of the most challenging issue is the handling of running instances when their schemata are modified: simple solutions can be devised, but they often imply losing all the work done or failing in capturing the advantages offered by workflow modifications; this is unacceptable for many applications. In this paper we address the problem of workflow evolution, from both a static and a dynamic point of view. We define a complete, minimal, and consistent set of modification primitives that allow modifications of workflow schemata and we introduce a taxonomy of policies to manage evolution of running instances when the corresponding workflow schema is modified. Formal criteria are introduced, based on a simple workflow conceptual model, in order to determine which running instances can be transparently migrated to the new version. A case study, relating the assembling of a desktop computer, will exemplify the introduced concepts.     

基于信息系统的工作流版本管理

目前工作沆管理系统缺乏对业务过程所涉及的应用信息系统版本的一致性管理,阻碍了工作流技术在多信息系统协同工作环境下的应用。本文在提出基于信息系统的工作流平台概念的基础上,给出工作流应用信息系统版本数据模型,提供有效的工作流应用信息系统版本一致性检测机制和具体算法。     

Multi-vehicle consensus with a time-varying reference state

In this paper, we study the consensus problem in multi-vehicle systems, where the information states of all vehicles approach a time-varying reference state under the condition that only a portion of the vehicles (e.g., the unique team leader) have access to the reference state and the portion of the vehicles might not have a directed path to all of the other vehicles in the team. We first analyze a consensus algorithm with a constant reference state using graph theoretical tools. We then propose consensus algorithms with a time-varying reference state and show necessary and sufficient conditions under which consensus is reached on the time-varying reference state. The time-varying reference state can be an exogenous signal or evolve according to a nonlinear model. These consensus algorithms are also extended to achieve relative state deviations among the vehicles. An application example to multi-vehicle formation control is given as a proof of concept.     

工作流程管理系统中的资源管理框架

资源管理是流程管理系统设计中的一个重要环节。在企业复杂的计算环境中，工作流程管理系统所要面对的是各种各样、数量庞大的资源。这些资源对象通常分布于企业信息的各个子系统中，为使工作流程管理系统既能够有效地对资源进行访问和管理，又能够使工作流程管理系统对特定资源保持独立性。本文提出一个面向工作流程管理系统的资源管理模型和接口。     

策略约束面向角色和团队关系的工作流任务分配管理

对任务分配进行有效的管理是适应性工作流中实现动态调整和适应性调整的关键因素之一，WfMC工作流元模型以及绝大多数的工作流管理系统中都引入了基于角色的任务分配，但是很多忽视企业典型工作方式－团队工作方式－与任务分配之间的关系，为此，提出了一个面向角色与团队的混合任务分配方式，并通过层次性策略来约束与协调任务分配中的复杂情况，进一步提高了工作流的适应性，在此基础上建立一个基于单列表，多视图的任务分配管理的实现机制。该方法虽然增加了工作流引擎的复杂性，但更符合企业的工作模式，方便业务建模及实施。     

Workflow modeling for virtual processes: an order-preserving process-view approach

Conducting workflow management allows virtual enterprises to collaboratively manage business processes. Given the diverse requirements of the participants involved in a business process, providing various participants with adequate process information is critical to effective workflow management. This work describes a novel process-view, i.e., an abstracted process which is derived from a base process to provide process abstraction, for modeling a virtual workflow process. The proposed process-view model enhances the conventional activity-based process models by providing different participants with various views of a process. Moreover, this work presents a novel order-preserving approach to derive a process-view from a base process. The approach proposed herein can preserve the original ordering of activities in the base process. Additionally, a formal model is presented to define an order-preserving process-view. Finally, an algorithm is proposed for automatically generating an order-preserving process-view. The proposed approach increases the flexibility and functionality of workflow management systems.     

Improving situation awareness in crisis response teams: An experimental analysis of enriched information and centralized coordination

In responding to an emergency, the actions of emergency response teams critically depend upon the situation awareness the team members have acquired. Situation awareness, and the design of systems to support it, has been a focus in recent emergency management research. In this paper, we introduce two interventions to the core processes of information processing and information sharing in emergency response teams to analyze their effect on the teams’ situation awareness: (1) we enrich raw incoming information by adding a summary of the information received, and (2) we channel all incoming information to a central coordinator who then decides upon further distribution within the team. The effect of both interventions is investigated through a controlled experiment with experienced professional responders. Our results show distinctly different effects for information enrichment and centralization, both for the teams and for the coordinators within the team. While the interaction effects of both conditions cannot be discerned, it is apparent that processing non-enriched information and non-centralized information sharing leads to a worse overall team situation awareness. Our work suggests several implications for the design of emergency response management information systems.     

Human–automation teams and adaptable control for future air traffic management

The design and management of human–automation teams for future air traffic systems require an understanding of principles of cognitive systems engineering, allocation of function and team adaptation. The current article proposes a framework of human–automation team adaptable control that incorporates adaptable automation [Oppermann, R., Simm, H., 1994. Adaptability: user-initiated individualization. In: Oppermann, R. (Ed.), Adaptive User Support: Ergonomic Design of Manually and Automatically Adaptable Software. Lawrence Erlbaum Associates, Hillsdale, NJ, pp. 14–64] with an Extended Control Model of Joint Cognitive System functioning [Hollnagel, E., Nåbo, A., Lau, I., 21–24 July 2003. A systemic model for driver-in-control. In: Paper Presented at the Second International Driving Symposium on Human Factors in Driver Assessment, Training, and Vehicle Design, Public Policy Center, University of Iowa, Park City, UT] nested within a dynamic view of team adaptation [Burke, C.S., Stagl, K.C., Salas, E., Pierce, L., Kendall, D., 2006. Understanding team adaptation: a conceptual analysis and model. Journal of Applied Psychology 91, 1189–1207]. Modeling the temporal dynamics of the coordination of human–automation teams under conditions of Free Flight requires an appreciation of the episodic, cyclical nature of team processes from transition to action phases, along with the distinction of team processes from emergent states [Marks, M.A., Mathieu, J.E., Zaccaro, S.J., 2001. A temporally based framework and taxonomy of team processes. Academy of Management Review 26, 356–376]. The conceptual framework of human–automation team adaptable control provides a basis for future research and design.

Relevance to industry

The current article provides a conceptual framework to direct future investigations to determine the optimal design and management of Human–automation teams for Free Flight-based air traffic management systems.     

Relationship Conflict,Conflict Management,and Performance of Information Technology Teams

This study examines how team collaboration and goal setting mediate the effects of team relationship conflict and conflict management on team performance. Primary data were collected from students who worked in teams to design functional information systems (IS). The data were then analyzed using structural equations modeling (SEM). The mediators – team collaboration and goal setting – positively affected each other and performance. Full results support a partial mediation model in which 60% of the total effect of relationship conflict and 80% of the total effect of conflict management on team performance are carried through team collaboration and goal setting. This work is the first of its kind that theoretically posits and empirically tests a mechanism through which team conflict and its management relate to team performance.     

Illuminating Recommendation by Understanding the Explicit Item Relations

Recent years have witnessed the prevalence of recommender systems in various fields, which provide a personalized recommendation list for each user based on various kinds of information. For quite a long time, most researchers have been pursing recommendation performances with predefined metrics, e.g., accuracy. However, in real-world applications, users select items from a huge item list by considering their internal personalized demand and external constraints. Thus, we argue that explicitly modeling the complex relations among items under domain-specific applications is an indispensable part for enhancing the recommendations. Actually, in this area, researchers have done some work to understand the item relations gradually from “implicit” to “explicit” views when recommending. To this end, in this paper, we conduct a survey of these recent advances on recommender systems from the perspective of the explicit item relation understanding. We organize these relevant studies from three types of item relations, i.e., combination-effect relations, sequence-dependence relations, and external-constraint relations. Specifically, the combination-effect relation and the sequence-dependence relation based work models the intra-group intrinsic relations of items from the user demand perspective, and the external-constraint relation emphasizes the external requirements for items. After that, we also propose our opinions on the open issues along the line of understanding item relations and suggest some future research directions in recommendation area.     

Dynamic checking of temporal constraints for concurrent workflows

At present, workflow management systems have not sufficiently dealt with the issues of time, involving time modelling at build-time and time management at run-time. They are lack of the ability to support the checking of temporal constraints at run-time. Although some approaches have been devised to tackle this problem, they are limited to a single workflow and use only static techniques to verify temporal constraints. In reality, there are multiple workflows executing concurrently in a workflow management system. There may well exist resource constraints between these concurrent workflows, which affect significantly the verification of temporal constraints at run-time. This paper proposes a novel approach for dynamic verification of temporal constraints for concurrent workflows. We first investigate resource constraints in workflow management systems, and then define concurrent workflow executions. Based on these definitions, we propose a verification method by analysing the temporal relationship and resource constraints between activities among concurrent workflows.     

Novel structures for counting frequent items in time decayed streams

Identifying frequently occurring items is a fundamental building block in many data stream applications. A great deal of work for efficiently identifying frequent items has been studied on the landmark and sliding window models. In this work, we revisit this problem on a new streaming model based on the time decay, where the importance of every arrival item is decreased over the time. To address the importance changes over time, we propose an innovative heap structure, named Quasi-heap, which maintains the item order using a lazy update mechanism. Two approximation algorithm, Space Saving with Quasi-heap (SSQ) and Filtered Space Saving with Quasi-heap (FSSQ), are proposed to find the frequently occurring items based on the Quasi-heap structure. To achieve better accuracy of frequency estimation for all the items in the stream, we introduce a new count-min-min (CMM) sketch structure, which can estimate the count of an item with almost error free. Extensive experiments conducted on both real-world and synthetic data demonstrate the superiority of proposed methods in terms of both efficiency (i.e., response time) and effectiveness (i.e., accuracy).