Abstract not found

The title of this paper was chosen to highlight the fact that the label CSCW, although widely adopted as the acronym for the field of Computer Supported Cooperative Work, has been applied to computer applications of very different ilk. It is not at all clear what are the unique identifying elements of this research area. This paper provides a framework for approaching the issue of cooperative work and its possible computer support. The core issues are identified and prospects for the field are outlined.

Over the last 10 years, Computer-Supported Cooperative Work (CSCW) has identified a base set of findings. These findings are taken almost as assumptions within the field. In summary, they argue that human activity is highly flexible, nuanced, and contextualized and that computational entities such as information transfer, roles, and policies need to be similarly flexible, nuanced, and contextualized. However, current systems cannot fully support the social world uncovered by these findings. This paper argues that there is an inherent gap between the social requirements of CSCW and its technical mechanisms. The social-technical gap is the divide between what we know we must support socially and what we can support technically. Exploring, understanding, and hopefully ameliorating this social-technical gap is the central challenge for CSCW as a field and one of the central problems for HCI. Indeed, merely attesting the continued centrality of this gap could be one of the important intellectual contributions of CSCW. This paper also argues that the challenge of the social-technical gap creates an opportunity to refocus CSCW as a Simonian science of the artificial. To be published in Human-Computer Interaction Preprint- Ackerman- Challenge of CSCW 1 1.

. Floor control allows users of networked multimedia applications to utilize and share resources such as remote devices, distributed data sets, telepointers, or continuous media such as video and audio without access conflicts. Floors are temporary permissions granted dynamically to collaborating users in order to mitigate race conditions and guarantee mutually exclusive resource usage. A general framework for floor control is presented. Collaborative environments are characterized and the requirements for realization of floor control will be identified. The differences to session control, as well as concurrency control and access control are elicited. Based upon a brief taxonomy of collaboration-relevant parameters, system design issues for floor control are discussed. Floor control mechanisms are discerned from service policies and principal architectures of collaborative systems are compared. The structure of control packets and an application programmer's interface are proposed and...

We have developed a new framework for supporting concurrency control in collaborative applications. It supports multiple degrees of consistency and allows users to choose concurrency control policies based on the objects they are manipulating, the tasks they are performing, and the coupling and merge policies they are using. Concurrency control policies are embodied in hierarchical, constructor-based lock compatibility tables. Entries in these tables may be specified explicitly or derived automatically from coupling and merge policies. In this paper, we motivate and describe the framework, identify several useful concurrency control policies it can support, evaluate its flexibility, and give conclusions and directions for future work. Keywords Concurrency control, collaborative systems, consistency criteria, coupling, merging, transactions INTRODUCTION When two or more users collaborate through jointly manip- ulating a shared object---be it an electronic whiteboard, a document, or ...

Abstract. This paper contributes to the design of Groupware Calendar Systems (GCSs) for use in domestic life. We consider a number of ethnographic studies of calendar use in domestic circumstances to illuminate the design space and inform design reasoning. GCSs have been employed in the workplace for sometime and have been informed by studies of ‘calendar work’. As design moves out of the workplace and into the home, the unique demands of domestic use now need to be considered. Existing insights into calendar work are restricted to the workplace however, and are constrained by analytic taxonomies. In the absence of first-hand knowledge of calendar use in domestic settings, we suspend the use of taxonomies and describe the ‘interpretive work ’ implicated in calendar work in order to explicate real world practices of calendar use in domestic life. These novel studies draw attention to a corpus of accountable work-practices that impact directly on design. In particular, they emphasize the need for design to consider how the physical and the digital may be merged to support collaboration ‘anywhere, anytime’; the necessity of devising negotiation protocols supporting computer-mediated communication; and the development of collaborative access models and interaction techniques to support data sharing.

The design of Computer-Supported Cooperative Work (CSCW) systems involves a variety of disciplinary approaches, drawing as much on sociological and psychological perspectives on group and individual activity as on technical approaches to designing distributed systems. Traditionally, these have been applied independently---the technical approaches focussing on design criteria and implementation strategies, the social approaches focussing on the analysis of working activity with or without technological support. However, the disciplines are more strongly related than this suggests. Technical strategies---such as the mechanisms for data replication, distribution and coordination---have a significant impact on the forms of interaction in which users can engage, and therefore on how their work proceeds. Consequently, the findings of sociological and psychological investigations of collaborative working have direct impact for how we go about designing collaborative systems. I...

Inter-organizational cooperation has specific requirements for access control. The paper presents the results from a field study which looks at the cooperation between two engineering offices and a steel mill. Based on these findings we have developed new mechanisms for access control in groupware. These mechanisms allow to restrict operations on shared data while or even after they take place. The new access mechanisms can be decomposed and implemented into a component-based framework. We show how this framework can be extended to realize additional mechanisms for access control with little efforts.

This paper examines the importance of providing effective management of sharing in cooperative systems and argues for a specialised service to support the cooperative aspects of information sharing. The relationship between features of the cooperative shared object service and existing services is briefly examined. A number of management services of particular importance to CSCW systems are identified. The paper presents a technique of realising a shared object service by augmenting existing object facilities to provide management of their cooperative use. These facilities are realised through object adapters that provide additional cooperative facilities and greater control over the supporting infrastructure. KEYWORDS: Information Sharing, Distributed Systems Support, Cooperative Systems Infrastructure. INTRODUCTION Shared information plays a central role in CSCW systems. It is often the primary means used to develop a shared understanding across a number of users working together. Th...

This report proposes a security model designed to support cooperative tasks in which the security of the information used and produced is critical, and where the participants in a task are not equally trusted. This approach will support a range of security policies, including those in which the rights of participants in cooperative tasks are restricted to just those that they need in order to perform their roles - so-called `minimum privilege' policies. The model is designed to be implemented in a variety of distributed system environments, assuming a minimum of trusted system components. We describe an approach to the implementation of the security model in the context of a shared distributed object system and we outline an implementation architecture for an open distributed security system that will allow several security models to coexist in a single distributed system. The model has two levels at which access control is represented -- user level and programming level. Security poli...