Clarence A. Ellis

Groupware: some issues and experiences

Groupware reflects a change in emphasis from using the computer to solve problems to using the computer to facilitate human interaction. This article describes categories and examples of groupware and discusses some underlying research and development issues. GROVE, a novel group editor, is explained in some detail as a salient groupware example

Concurrency control in groupware systems

Groupware systems are computer-based systems that support two or more users engaged in a common task, and that provide an interface to a shared environment. These systems frequently require fine-granularity sharing of data and fast response times. This paper distinguishes real-time groupware systems from other multi-user systems and discusses their concurrency control requirements. An algorithm for concurrency control in real-time groupware systems is then presented. The advantages of this algorithm are its simplicity of use and its responsiveness: users can operate directly on the data without obtaining locks. The algorithm must know some semantics of the operations. However the algorithms overall structure is independent of the semantic information, allowing the algorithm to be adapted to many situations. An example application of the algorithm to group text editing is given, along with a sketch of its proof of correctness in this particular case. We note that the behavior desired in many of these systems is non-serializable.

Dynamic change within workflow systems

Dynamic change is a large and pervasive unsolved problem which surfaces within office systems as well as within software engineering, manufacturing, and numerous other domains. Procedural changes, performed in an ad hoc manner, can cause inefficiencies, inconsistencies, and catastrophic breakdowns within offices. This paper is concerned with dynamic change to procedures in the context of workflow systems. How can we make workflow systems more flexible and open? We believe that part of the answer lies in the study and solution of the dynamic change problem. In this paper, we use a Petri net formalism to analyze structural change within office procedures. As an example, we define a class of change called “synthetic cut-over change”, and apply our formalism to prove that this class maintains correctness when downsizing occurs.

Operational transformation in real-time group editors: issues, algorithms, and achievements

Rd-time group editors dow a group of users to view and edit, the same document at the same time horn geograpbicdy di.~ersed sites connected by communication networks. Consistency maintenance is one of the most si@cant &alwiges in the design and implementation of thwe types of systems. R=earch on rd-time group editors in the past decade has invented au inuolative tetique for consistency maintenance, ded operational transformation This paper presents an integrative review of the evolution of operational tra=formation techniques, with the go~ of identifying the major is-m~s, dgotiths, achievements, and remaining Mlenges. In addition, this paper contribut= a new optimized generic operational transformation control algorithm. Ke~vords Consistency maint enauce, operational transformation, convergence, CauS*ty pras~ation, intention pre~tion, group e&tors, groupware, distributed computing.

Modeling and Enactment of Workflow Systems

Petri net models and variants thereof have primarily been used to model structured systems such as computer programs, factory production lines, and engineering hardware. In contrast, this paper discusses the issues and challenges in the modeling of human activity in the workplace. This type of activity frequently has a large component that is unstructured, creative work. It is dynamic and difficult to capture via traditional Petri nets. Our research group at the University of Colorado has been investigating Information Control Nets (ICNs), derived from high level Petri nets, as a tool for modeling office workflow. After carefully explaining the notion of Workflow, this paper presents a formal (and also an informal) definition of ICN. We illustrate the utility of ICNs via an office analysis example.

A conceptual model of groupware

This paper discusses a conceptual model of groupware consisting of three complementary components or models: a description of the objects and operations on these objects available in the system; a description of the activities (and their orderings) that the users of the system can perform; and a description of the interface of users with the system, and with other users.

PROCLETS: A FRAMEWORK FOR LIGHTWEIGHT INTERACTING WORKFLOW PROCESSES

The focus of traditional workflow management systems is on control flow within one process definition. The process definition describes how a single case (i.e. workflow instance) in isolation is handled. For many applications this paradigm is inadequate. Interaction between cases to support communication and collaboration is at least as important. This paper introduces and advocates the use of interacting proclets, i.e. lightweight workflow processes. By promoting interactions to first-class citizens it is possible to model complex workflows in a more natural manner. In addition, the expressive power and flexibility are improved compared to the more traditional workflow modeling languages.

Project Nick: meetings augmentation and analysis

The Software Technology Program of MCC is investigating the early part of the design process, before requirements are established, for large-scale distributed systems. Face-to-face meetings are an important activity during this phase of a project since they provide a medium for direction, exploration, and consensus building. Project Nick is attempting to apply automated facilities to the process, conduct, and semantic capture of design meetings. Primary topics covered in this paper are meeting analysis, meeting augmentation, and a model of meeting progression that serves as the framework for our work.

A Workflow Change Is a Workflow

Organizations that are geared for success within todays business environments must be capable of rapid and continuous change. This business reality is boosting the popularity of various types of workflow systems. However, current workflow systems are not yet capable of facing the ever-changing nature of their business environment. Part of the answer to the challenge, in our view, lies in change understanding, communication, implementation, and analysis. In this chapter, we present an overview of our work on modeling dynamic change within workflow systems. This work was recently completed by the introduction of ML-DEWS, a Modeling Language to support Dynamic Evolution within Workflow Systems. We firmly believe the thesis put forth in this chapter that a change is a process that can be modeled, enacted, analyzed, simulated and monitored as any process.

Workflow Modeling Using Proclets

The focus of traditional workflow management systems is on control flow within one process definition, that describes how a single case (i.e., work-flow instance) is handled in isolation. For many applications this paradigm is inadequate. Interaction between cases is at least as important. This paper introduces and advocates the use of interacting proclets, i.e., light-weight workflow processes. By promoting interactions to first-class citizens, it is possible to model complex workflows in a more natural manner, with improved expressive power and flexibility.