Rodden, T. Q'fyh#vt##ur#6ffyvph#v')#6#H'qry#'s 6#h...rr++#s'...#8"fr...h#vo/oor#6ffyvph#v'+, ComputerSupported Cooperative Work (CSCW'96), Boston, Mass, 1996.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....as a whole or for a given work package. The WORKWARE awareness monitor provides notifications of events on tasks that the users are interested in. The relationships between tasks and the allocation of people to tasks is utilised to deduce what users need to know about which events, as proposed by [42, 44]. This is another example of model activation, where the model is utilised to channel the flow of awareness notifications, personalising them based on each user s participation in the process. Awareness complements interactive enactment (described above) to help users coordinate their work. While ....

Rodden, T. Q'fyh#vt##ur#6ffyvph#v')#6#H'qry#'s 6#h...rr++#s'...#8"fr...h#vo/oor#6ffyvph#v'+, ComputerSupported Cooperative Work (CSCW'96), Boston, Mass, 1996.

....still possible for these applications to share the application independent information of their users and groups. 1 Introduction The emerging need for software supporting group cooperation is indicating that computers are increasingly used for collaborative group work. Rodden, Mariani and Blair [13] point out that the traditional support offered by operating systems often fails to be useful for cooperative applications. A result of this situation is the development of groupware (as we will call software supporting collaborative work throughout this paper) today, where every application ....

T. Rodden, J. A. Mariani, and G. Blair. Supporting cooperative applications. Computer Supported Cooperative Work, 1(1--2):41--67, 1992.

....item [Stefik 87] In Colab this approach has yielded unacceptable delays for obtaining locks. 10 Transaction mechanisms also support pessimistic concurrency control but have been reported as not well suited to interactive use due to limitations in response time and notification time [Ellis 91,Rodden 92] Barghouti 91] reports that serializable concurrency control might decrease concurrency or, more significantly, actually prevent desirable forms of cooperation. CoVer [Haake 93] uses a versioning system for avoiding conflicts. The system monitors changes to objects and when detects conflicts ....

T. Rodden, J. Mariani, and G. Blair. Supporting cooperative applications. Computer Supported Cooperative Work, 1:41--67, 1992.

....presented in this paper can be used for group and session management support within different group communications platforms. A description of the implementation as well as implementation results are given in the last section. 1 Introduction Over the past years, surveys by various authors [13, 29, 31, 37, 51] have shown the increasing need for multipoint communications and the requirements for platforms supporting this type of communications. Additionally, the requirements of transporting multimedia data has also been applied to multipoint communications [6, 12, 20, 44] leading to multipoint ....

T. Rodden, J. A. Mariani, and G. Blair. Supporting Cooperative Applications. Computer Supported Cooperative Work, 1(1--2):41--67, 1992.

....management and security issues. The architecture presented in this paper is transport independent, ie it can be used within different group communication platforms. A short sketch of the implementation is given in the last section. 1. INTRODUCTION Over the past years, surveys by various authors [1, 2, 3] have shown the increasing need for multipoint communications and the requirements for platforms supporting this type of communications. Additionally, the requirement for multimedia data transport is also applied to multipoint communications. One common approach for designing a platform which ....

T. Rodden, J. A. Mariani, and G. Blair. Supporting Cooperative Applications. Computer Supported Cooperative Work, 1(1--2):41--67, 1992.

....of cooperative interaction has to be investigated in order to choose and or adapt a suitable concept of concurrency control. In general, systems allowing synchronous cooperative access need more sophisticated concurrency techniques than asynchronous systems which may exploit locking mechanisms [129]. In [70] six different modes of cooperation on shared materials for cooperative design situations have been identified. The identified modes are shortly described and discussed with the focus on the degree of concurrency control needed: 1. Separate responsibilities. A publication is divided into ....

....same object is informed that it is already locked by an identified user. As asynchronous cooperative work usually has the result that the duration of object locking is rather longer than in traditional database applications, it would be useful to provide time information about those activities too [129]. Chapter 4 Concepts and Design This chapter contains both concepts from literature and design decisions which we have made while realizing a prototype distributed hypermedia document management system. The basic framework for computer support for a distributed publishing environment is ....

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Rodden, T., Mariani, J., and Blair, G. Supporting Cooperative Applications. Computer Supported Cooperative Work 1, 1--2 (1992), 41-- 67.

....ownership of that item [51] In Colab this approach has yielded unacceptable delays for obtaining locks. Transaction mechanisms also support pessimistic concurrency control but have been reported as not well suited to interactive use due to limitations in response time and notification time [15,46]. 5] reports that serializable concurrency control might decrease concurrency or, more significantly, actually prevent desirable forms of cooperation. CoVer [23] uses a versioning system for avoiding conflicts. The system monitors changes to objects and when detects conflicts it creates new ....

T. Rodden, J. Mariani, and G. Blair. Supporting cooperative applications. Computer Supported Cooperative Work, 1:41--67, 1992.

.... are low level and limited to message passing or remote procedure call (RPC) While this is sufficient for information processing applications with simple client server or three tier communication requirements, it falls short of supporting the flexibility and complexity required by CSCW systems[6, 22, 14]. There are a number of research oriented toolkits, for example GroupKit[23] and COAST[25] that support some of the required facilities for CSCW applications. These do not easily support extension or composition of facilities, however, because of their toolkit nature. In his recent PhD ....

T. Rodden, J. A. Mariani, and G. Blair. Supporting cooperative applications. Computer Supported Cooperative Work, 1:41--67, 1992.

....of the cooperation requirements taken into account by the distributed systems people. Results are now visible in networks, operating systemand storage support. An in depth study of supporting techniques for CSCW and their impacts on distributed systems and database technology can be found in [46]. The next generation of groupware platform should provide support for sharing existing applications so as to benefit from the large amount of existing software. The mechanismsprovided should allow control based on a replicated architecture which appears to be the most promising direction because ....

T. Rodden, Mariani J.A., and Blair G. Supporting Cooperative Applications. Computer Supported Cooperative Work, 1(1-2):41--67, 1992.

....gives good performance but at the cost of considerable consistency and synchronization problems. Other researchers [28, 17, 3] suggest that a semi replicated architecture is a good solution which manages to keep both communication, consistency, and synchronization costs at a low level. Others [58, 65] advocate that full fledged distributed systems support should be incorporated into groupware tools. It is also interesting to note that the distributed systems community, e.g. the ISIS toolkit [5] starts to take groups into account. Issues related to the choice of architecture are scalability ....

....optimistic concurrency control algorithm is described in [50] 1.2.3 Network Technology Cerf [8] gives a good overview of general network communication issues. Discussions of how current network technology satisfies the communication requirements of groupware applications can be found in [47] and [58]. As digital, continuous media are beginning to be incorporated into groupware applications, networks will face tougher bandwidth requirements. Fox [25] explains what these requirements are and how compression techniques can help reduce them. One issue that is of particular concern to groupware is ....

T. Rodden, J. A. Mariani, and G. Blair. Supporting cooperative applications. Computer Supported Cooperative Work (CSCW), 1(1):41--67, 1992.

....to the medium or avoid verbal exchanges. 2.2 Technological issues The role of technology in group processes presents many positive aspects. For example, technology can bring more individual knowledge to the group discussions by supporting knowledge sharing, representation and visualization tools [22, 33, 30]; levels of participation are enhanced with contributions from members located in different sites of the organization; and organizational memory can be augmented with more relevant data: issues, comments, votes, decisions [8] However, current technologies face important problems to support ....

....comments, votes, decisions [8] However, current technologies face important problems to support distributed cooperations. The cultural familiarities of face to face meetingsshould be kept to remote members [18] but are challenged by the low throughput and long feedback delays of current networks [30]. The articulation of cooperative work and sharing of information space also poses important user interface issues [4] As pointed out in [25] the effects introduced by the media in the group processes are not only related with the problems posed by the reduced bandwidth compared with the ....

T. Rodden, J. Mariani, and G. Blair. Supporting cooperative applications. Computer Supported Cooperative Work, 1:41--67, 1992.

....in a number of different ways, ranging from very low level, being concerned only with transport technology, to very abstract models, which take multimedia multipoint communications for granted and deal only with the design of applications and their interfaces. In general, various surveys [5, 16, 17, 19, 26] have shown that the need for communication platforms supporting multipoint communications is increasing. However, we feel that there is much more work being done in the field of multimedia than in the field of multiuser communication systems. In this paper, we describe a system which is ....

T. Rodden, J. A. Mariani, and G. Blair. Supporting Cooperative Applications. Computer Supported Cooperative Work, 1(1--2):41--67, 1992.

....to existing groups. These differences could be hidden by the support platform for collaborative applications. Based on these assumptions, it is necessary to analyze the requirements of collaborative applications. Some work on this field has already been done, eg the articles by Rodden et al. [20, 21], or the article by Heijenk et al. 9] However, most of the literature is about support for specific applications or application types. The following sections focus on different areas of communication support for collaborative applications. Section 3.1 deals with names, ie the abstract entities ....

T. Rodden, J. A. Mariani, and G. Blair. Supporting Cooperative Applications. Computer Supported Cooperative Work, 1(1--2):41--67, 1992.

....The advantages are: ffl It simplifies the interface to the FS. ffl It allows FS to be tuned for a whole range of applications. Typical default threshold values, weights and sample rates are defined using known specifications of responsiveness and estimated bandwidth for the target applications [18]. For example, in [5] it is recommended that notification and response times should be comparable. We consider high responsiveness typically below 2 seconds while low requirement means accommodating delay values above 10 seconds. Note that local computing overhead is not taken into account since ....

T. Rodden, Mariani J.A., and Blair G. Supporting Cooperative Applications. Computer Supported Cooperative Work, 1(1-2):41--67, 1992.

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