Publications

 

Context-Aware Multimedia Computing in the Intelligent Hospital

Scott Mitchell, Mark D. Spiteri, John Bates and George Coulouris

Proceedings of the 9th ACM SIGOPS European Workshop, Kolding, Denmark, September 2000

 

An Architecture for the Storage, Notification and Retrieval of Events

Mark D. Spiteri

PhD Thesis, Technical Report No:494, University of Cambridge Computer Laboratory, June 2000

 

Generic Support for Asynchronous, Secure Distributed Applications

Jean Bacon, Ken Moody, John Bates, Chaoying Ma, Andrew McNeil, Oliver Seidel and Mark D. Spiteri

IEEE Computing, March 2000

 

Capturing and Indexing Computer-based Activities With Virtual Network Computing

Sheng Feng Li, Mark D. Spiteri, John Bates, and Andy Hopper

Proceedings of the ACM Symposium on Applied Computing, Como, Italy. March 2000

 

Active Management of Multi-Service Networks

Ian Marshall, John Bates, Mark D. Spiteri, Chris Mallia and L. Velasco

IEE Electronics and Communications Colloquium on "Control of next generation networks", London, United Kingdom. October 1999

 

An Architecture to support Storage and Retrieval of Events

Mark D. Spiteri and John Bates

Proceedings of MIDDLEWARE 1998, IFIP International Conference on Distributed Systems Platforms and Open Distributed Processing, Lancaster, United Kingdom. September 1998

 

Using Events for the Scalable Federation of Heterogeneous Components

John Bates, Jean Bacon, Ken Moody and Mark D. Spiteri

Proceedings of 8th ACM SIGOPS European Workshop, Sintra, Portugal. September 1998

 

Integrating Real-World and Computer-Supported Collaboration in the Presence of Mobility

John Bates, Mark D. Spiteri, David Halls and Jean Bacon

Proceedings of IEEE 7th International Workshops in Enabling Technologies: Infrastructure for Collaborative Enterprises, Stanford, CA USA. June 1998

This paper was awarded "Best Paper Overall of Conference".

 

 

 

 

Context-Aware Multimedia Computing in the Intelligent Hospital

 

Scott Mitchell, Mark D. Spiteri, John Bates and George Coulouris

 

Proceedings of the 9th ACM SIGOPS European Workshop

Kolding, Denmark, September 2000

 

This paper describes an application middleware that addresses the requirement for immediate high-quality multimedia communications in environments where users' work practices exhibit a large degree of physical mobility. A modern hospital is one such environment, with diverse, often mission-critical, communication needs that are not addressed adequately by existing systems. By integrating a multimedia framework with an event-based notification system, we are developing QoS DREAM, a platform that can provide seamless, context-sensitive communications, which can adapt to users' location and even follow them around. This paper describes how we are using QoS DREAM to design what we term our concept of the "Intelligent Hospital". We also introduce a usability study that we are currently engaged in. This is allowing us to determine a realistic set of communication and information access requirements within a busy hospital environment. We conclude by illustrating a prototype of the system.

 

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An Architecture for the Storage, Notification and Retrieval of Events

 

Mark D. Spiteri

 

PhD Thesis

Technical Report No:494

University of Cambridge Computer Laboratory, June 2000

 

Event-driven and messaging infrastructures are emerging as the most flexible and feasible solution to enable rapid and dynamic integration of legacy and monolithic software applications into distributed systems. They also support deployment and enhancement of traditionally difficult-to-build active systems such as large-scale collaborative environments and mobility aware architectures. However, complex systems issues like mobility, scalability, federation and persistence indicate a requirement for more advanced services within these infrastructures. The event notification paradigm is also applicable in emerging research areas such as modelling of business information flow within organisations, as well as workplace-empowering through enhanced awareness of work practices relating to communication and interaction between individuals. In these areas, further developments require complex interpretation and correlation of event information, highlighting the need for an event storage and retrieval service that provides the required groundwork.

 

It is the thesis of this dissertation that the lack of a generic model for event representation and notification has restricted evolution within event-driven applications. Furthermore, in order to empower existing applications and enable novel solutions, a crucial, and so-far-missing, service within event-driven systems is capture, persistent storage, and meaningful retrieval of the messaging information driving these systems.

 

In order to address these issues, this dissertation defines a generic event model and presents a powerful event notification infrastructure that, amongst other structural contributions, embeds event storage functionality. An event repository architecture will then be presented that can capture and store events, as well as inject them back into distributed application components to simulate replay of sequences of activity. The general-purpose architecture presented is designed on the thesis that events are temporal indexing points for computing activities. Changes in the state of a distributed system can be captured as events, and replayed or reviewed at a later stage, supporting fault-tolerance, systems management, disconnected operation and mobility. The architecture delivers powerful querying of event histories, enabling extraction of simple and composite event patterns. This addresses the business requirement in several industries (such as finance, travel, news, retail and manufacturing) to locate temporal patterns of activity, as well as support applications like memory prosthesis tools and capture of collaboration. The repository offers a selective store-and-forward functionality that enables messaging environments to scale and provide enhanced brokering and federation services.

 

In addition to enabling novel applications, the general-purpose infrastructure presented provides a more flexible approach to event notification, storage and retrieval, in areas where bespoke solutions had to be provided previously. The theoretical concepts illustrated in this dissertation are demonstrated through a working distributed implementation and deployment in several application scenarios.

 

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Generic Support for Asynchronous, Secure Distributed Applications

 

Jean Bacon, Ken Moody, John Bates, Chaoying Ma, Andrew McNeil, Oliver Seidel and Mark D. Spiteri.

 

IEEE Computing

March 2000

 

We describe how distributed applications are supported at present by middleware and show that extensions are needed if emerging requirements are to be met.We have worked to extend middleware in the areas of asynchronous operation and security. The Cambridge Event Architecture (CEA) is based on a publish, register, notify paradigm with event object classes and source-side filtering based on parameter templates. Standard platform technology is used: the interface definition language (IDL) is used to publish events and automatic stub generation is used for event noti fication. Asynchronous notification allows a system to respond immediately to the occurrence of events, such as the detection of a mobile user or the withdrawal of access rights from an individual. Event notification may also be used to compose independently developed components. Our security architecture, Oasis, runs on a middleware platform extended for asynchronous operation. Oasis is concerned with the secure interoperability of independently developed services. For scalability, an Oasis server may name its many users in terms of a number of roles; access rights are associated with roles. Entry to a named role of a service is restricted to those that can prove they belong to other named roles of this and/or other services. Our work is wide in scope, being applicable to many human organisations which have multi-service information systems.

 

 

 

Active Management of Multi-Service Networks

 

Ian Marshall, John Bates, Mark D. Spiteri, Chris Mallia and L. Velasco

 

IEE Electronics and Communications Colloquium on "Control of next generation networks"

London, United Kingdom, October 1999

 

The increasing need for rapid introduction of new services and highly customised service offerings poses additional management challenges for today's networks. In this paper we propose a flexible distributed management system based on role driven policies and active layer networking that addresses these demands. Management information is distributed via a hierarchy of Information Servers which accommodate different storage and propagation requirements. The design and implementation of these Information Servers is described in detail as is their integration with an existing commercial management solution.

 

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Capturing and Indexing Computer-based Activities With Virtual Network Computing

 

Sheng Feng Li, Mark D. Spiteri, John Bates, and Andy Hopper

 

Proceedings of the ACM Symposium on Applied Computing

Como, Italy, March 2000

 

In this paper, we present a new technique to capture and index computer-based activities, without hindering natural human-computer interactions. This technique is based on the Virtual Network Computing (VNC) technology, which is an ultra-thin-client/server computing model that separates the display interface from the application logic in windowing systems. The server executes all the applications and the client simply presents the frame buffer updates to the user and accepts user input. We record the frame buffer updates for work review, and store the user and system events as potential indices into the recording.

 

 

 

An Architecture to support Storage and Retrieval of Events

 

Mark D. Spiteri and John Bates

 

Proceedings of MIDDLEWARE 1998, IFIP International Conference on Distributed Systems Platforms and Open Distributed Processing

Lancaster, UK, September 1998

 

This paper describes the architecture we designed and constructed to support the storage and retrieval of events. We define an event as an asynchronous occurrence containing parameterised details of an activity that has occurred within a distributed component. Our past experience has demonstrated how using events as the glue to build distributed active systems simplifies the construction of complex applications, and enables legacy stand-alone components to be rapidly integrated within a larger collaborative environment. Examples of such active systems are interactive multimedia applications, distributed debugging environments, co-operative working applications, agent architectures, and active databases. Our motivation for storing events is that events represent indexing points into application sessions. Our event repository architecture can capture and store events, as well as inject them back into distributed application components to simulate replay of sequences of activity, or for re-building lost state. The architecture co-exists and inter-operates with other event-based active systems, as well as with middleware event services like traders and brokers. Using a generic object-oriented model for events, the repository architecture provides powerful search and retrieval facilities, enabling extraction of behaviour patterns, searching for simple and composite occurrences, and replay of stored sequences. We illustrate how the repository can be a viable alternative to past system-specific solutions in areas like capture of collaboration and memory prosthesis, and visualisation of user mobility.

 

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Using Events for the Scalable Federation of Heterogeneous Components

 

John Bates, Jean Bacon, Ken Moody and Mark D. Spiteri

 

Proceedings of 8th ACM SIGOPS European Workshop

Sintra, Portugal, September 1998

 

The thesis of this paper is that, using our event-based development principles, components that were not designed to interoperate, can be made to work together quickly and easily. The only requirement is that each component must be made event-based by adding an interface to registering interest in events and an interface for injecting actions. A component notifies an event to a distributed client if the parameters of an event, internal to the component, match the parameters of a particular registration. Heterogeneous components can be federated using event-based rules; rules can respond to events from any component by injecting actions into any other component. We show that the event paradigm is scalable by illustrating how event-based components can be located worldwide, using a federation of event brokers. Additionally, we illustrate with 3 event-based systems we have developed: a component-based multimedia system, a multi-user virtual worlds system and an augmented reality system for mobile users. Finally, we show how the event paradigm is also scalable enough to allow event federation of entire systems, not just single components. We illustrate by showing how we have federated the operation of the 3 featured event based systems. This enables, for example, real-world mobile users to appear as avatars in the appropriate locations in the VR world, and for these avatars to move in response to actual user movements.

 

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Integrating Real-World and Computer-Supported Collaboration in the Presence of Mobility

 

John Bates, Mark D. Spiteri, David Halls and Jean Bacon

 

Proceedings of IEEE 7th International Workshops in Enabling Technologies: Infrastructure for Collaborative Enterprises

Stanford, CA USA, June 1998

 

This paper was selected as the "Best Paper Overall of Conference".

 

We have developed an environment in which Real-World Collaborative Working (RWCW) and Computer-Supported Collaborative Working (CSCW) can be seamlessly integrated. Real-world collaboration usually involves mobile individuals in casual or prearranged meetings with colleagues. On the other hand computer-supported collaboration involves using computer-based tools to cooperate, e.g. multimedia conferencing and shared design tools. Our environment generalizes activities from the real-world and computer-supported collaboration as events. This enables computer-based applications to be built around a mixture of both scenarios, e.g. a user, mobile in the real-world, may be using computer-supported tools to collaborate with other users. If the user moves between locations in the physical world, the computer-based tools he/she is using follow, being transported to the nearest, or a selected workstation. Our environment supports the automatic storage of events, both real-world and computer-supported, so that collaborative activities can be later replayed, queried, analyzed and visualized. It is our thesis that this paradigm effectively removes the limitations that each form of collaboration has in isolation, and applications like the ones we have been able to develop using this infra-structure can enhance individual and group productivity.

 

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November, 2007