undo in context-aware collaborative ubiquitous-computing environments
DESCRIPTION
A comprehensive approach to the design of Ubiquitous Computing systems must deal with the issues related to the restoration of an earlier or acceptable state of the system, if possible, when users intentionally want to undo some previous actions. Systems supporting collaborative Ubiquitous Computing environments should provide a default undo function, but also provide users and applications with awareness information to correctly decide which (compensative) actions should be undertaken. In this paper we describe how to achieve undo in distributed, dynamic, context-aware systems. We present a general approach to undo in collaborative Ubiquitous Computing environments in terms of the CASMAS model: part of the approach relies on the notion of active coordination artifacts, as defined also in CSCW literature.TRANSCRIPT
Undo in Context-aware Collaborative Ubiquitous-Computing Environments
Marco P. Locatelli and Marco LoregianUniversity of Milano-Bicocca (Italy)
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
Undo
• Well known function of PC applications• The capability of a system to perform a set
of actions to fulfill the will of the users to reach a state as if a previous command had never been given• Different possible strategies
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
Motivation
• Undo is essential to design usable (successful) systems
• Ubicomp systems must be provided with context-aware, smart (semi-proactive) undo functions, with compensation mechanisms
• Designers: keep the problem in mind and interact with users
• Developers: deal with the problem to achieve dynamic, distributed undo for context-aware systems
M. Loregian and M. P. Locatelli. An experimental analysis of undo in ubiquitous computing environments. In F. E. Sandnes, Y. Zhang, C. Rong, L. T. Yang, and J. Ma, editors, UIC, volume 5061 of Lecture Notes in Computer Science, pages 505–519. Springer, 2008.
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
CASMAS
M. P. Locatelli and M. Loregian. Active coordination artifacts in collaborative ubiquitous-computing environments. In B. Schiele, A. K. Dey, H. Gellersen, B. E. R. de Ruyter, M. Tscheligi, R. Wichert, E. H. L. Aarts, and A. P. Buchmann, editors, AmI, volume 4794 of Lecture Notes in Computer Science, pages 177–194. Springer, 2007.
Main features:
• double-layer model(cooperation + awareness)
• different kinds of agents
• communities (fulcra)
Our reference model in a nutshell
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
In the paper
We
• outlined the main problems of designing and implementing undo for context-aware collaborative ubiquitous-computing environments
• sketched some solutions for CASMAS-like systems
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
Distributed Undo
• Different entities involved: undo must propagate across scopes
• Coordination information can be used to enforce behaviors
• “Easy” with a complete explicit description, but what if there is no explicit process?
A. Agostini, G. De Michelis, and M. Loregian. Undo in Workflow Management Systems. In W. M. P. van der Aalst, A. H. M. ter Hofstede, and M. Weske, editors, Business Process Management, volume 2678 of Lecture Notes in Computer Science, pages 321–335. Springer-Verlag, 2003.
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undo command
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undo mechanisms
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
History as aCoordination Artifact
• With entities interacting in a dynamic, spontaneous, and not predictable way, system history can be used as a coordination artifact
• History helps entities to adapt to unexpected events
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undo command
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commandrecords
undo mechanisms
undo mechanisms
undo mechanisms
undo mechanisms
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
Undo with ActiveCoordination Artifacts
• Active Coordination Artifacts can actively interact with other entities
• They can dynamically carry context-aware undo policies
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undo command
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ACA
undo mechanisms
commandrecords
undo mechanisms
undo mechanisms
undo mechanisms
undo mechanisms
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
Conclusion
• It is necessary to provide interacting entities with alternative undo mechanisms, exploiting context information (awareness), instead of just a general purpose solution relying on fixed inverse specifications or compensation
• History can be adopted as a mean to enrich cooperation between entities when no static process specification can be given in advance
• If a support for coordination, such as active coordination artifacts, is introduced in the reference model, the same can be used to dynamically transport undo policies within and between ubicomp environments
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
Future Work
• Extension of the conceptual framework• We have also other ongoing works on undo (mobile
phones, email)
• Test the concepts in CASMAS scenarios• We have many scenarios modeled for straightforward
situations, we will show how undo can be handled
••• ITIS Lab ••• http://www.itis.disco.unimib.it •••
Undo in Context-aware CollaborativeUbiquitous-Computing Environments
Marco Loregian, Marco P. LocatelliUniversity of Milano-Bicocca (Italy)
Thank you,any question?