Context-driven agents in computer supported cooperative works

This thesis describes a research project that investigates the level of contextualization needed to successfully build context-driven agents that can manage a cooperative project. Many times in industry, collaborators in a large project may be located vast distances from each other. It is for this reason that management of such projects can often be difficult. The purpose of this research is to design an agent that can take on the role of a project manager (PM) to assist the human project manager. Specifically, this thesis looks to give such project management agents full situational awareness. It is hypothesized that only with situational awareness can an agent successfully act in the role of a project manager. This thesis describes the investigation into the use of Context-Based Reasoning and Contextual Graphs to create an agent with such situational awareness. This thesis shows that with enough situational awareness, an agent will have the ability to successfully take on the role of a project manager. In particular, this thesis looks at a PM-agent that can manage a simulated project to design and construct a small sounding rocket

Frameworks for enhancing temporal interface behaviour through software architectural design

The work reported in this thesis is concerned with understanding aspects of temporal behaviour. A large part of the thesis is based on analytical studies of temporal properties and interface and architectural concerns. The main areas covered include: i. analysing long-term human processes and the impact of interruptions and delays ii. investigating how infrastructures can be designed to support synchronous fast pace activity iii.design of the Getting-to-Know (GtK) experimental notification server The work is motivated by the failure of many collaborative systems to effectively manage the temporal behaviour at the interface level, as they often assume that the interaction is taking place over fast, reliable local area networks. However, the Web has challenged this assumption and users are faced with frequent network-related delays. The nature of cooperative work increases the importance of timing issues. Collaborative users require both rapid feedback of their own actions and timely feedthrough of other actions. Although it may appear that software architectures are about the internals of system design and not a necessary concern for the user interface, internal details do show up at the surface in non-functional aspects, such as timing. The focus of this work is on understanding the behavioural aspects and how they are influenced by the infrastructure. The thesis has contributed to several areas of research: (a)the study of long-term work processes generated a trigger analysis technique for task decomposition in HCI (b)the analysis of architectures was later applied to investigate architectural options for mobile interfaces (c)the framework for notification servers commenced a design vocabulary in CSCW for the implementation of notification services, with the aim of improving design (d)the impedance matching framework facilitate both goal-directed feedthrough and awareness In particular, (c) and (d) have been exercised in the development of the GtK separable notification server

Groupware design : principles, prototypes, and systems

Computers are valuable tools for a wide range of work tasks. A substantial limitation on their value, however, is the predominant focus on enhancing the work of individuals. This fails to account for the issues of collaboration that affect almost all work. Research into computer supported cooperative work (CSCW) aims to eliminate this deficiency, but the promise of computer systems for group work has not been met. This thesis presents four design principles that promote the development of successful groupware. The principles identify the particular problems encountered by groupware, and provide guidelines and strategies to avoid, overcome, or minimise their impact. Derived from several sources, the major influence on the principles development is an investigation into the relationship between factors affecting groupware failure. They are stimulated by observations of groupware use, and by design insights arising from the development of two groupware applications and their prototypes: Mona and TELEFREEK. Mona provides conversation-based email management. Several groupware applications allow similar functionality, but the design principles result in Mona using different mechanisms to achieve its user-support. TELEFREEK provides a platform for accessing computer-supported communication and collaboration facilities. It attends to the problems of initiating interaction, and supports an adaptable and extendible set of "social awareness" assistants. TELEFREEK offers a broader range of facilities than other groupware, and avoids the use of prohibitively high-bandwidth communication networks. TELEFREEK demonstrates that much can be achieved through current and widely accessible technology. Together, Mona and TELEFREEK forcefully demonstrate the use of the design principles, and substantiate the claim of their utility

Reducing the effect of network delay on tightly-coupled interaction

Tightly-coupled interaction is shared work in which each person’s actions immediately and continuously influence the actions of others. Tightly-coupled interaction is a hallmark of expert behaviour in face-to-face activity, but becomes extremely difficult to accomplish in distributed groupware. The main cause of this difficulty is network delay – even amounts as small as 100ms – that disrupts people’s ability to synchronize their actions with another person. To reduce the effects of delay on tightly-coupled interaction, I introduce a new technique called Feedback-Feedthrough Synchronization (FFS). FFS causes visual feedback from an action to occur at approximately the same time for both the local and the remote person, preventing one person from getting ahead of the other in the coordinated interaction. I tested the effects of FFS on group performance in several delay conditions, and my study showed that FFS substantially improved users’ performance: accuracy was significantly improved at all levels of delay, and without noticeable increase in perceived effort or frustration. Techniques like FFS that support the requirements of tightly-coupled interaction provide new means for improving the usability of groupware that operates on real-world networks

CVRetrieval: Separating Consistency Retrieval from Consistency Maintenance

In distributed online collaboration applications, such as digital white board and online gaming, it is important to guarantee the consistency among participants’ views to make collaboration meaningful. However, maintaining even a relaxed consistency in a distributed environment with a large number of geographically dispersed participants still involves formidable communication and management cost among them. In this paper, we propose CVRetrieval (Consistency View Retrieval) to solve this scalability problem. Based on the observation that not all participants are equally active or engaged in distributed online collaboration applications, CVRetrieval differentiates the notions of consistency maintenance and consistency retrieval. Here, consistency maintenance implies a protocol that periodically communicates with all participants to maintain a certain consistency level; and consistency retrieval means that passive participants (those with little updating activity) explicitly request a consistent view from the system when the need arises in stead of joining the expensive consistency maintenance protocol all the time. The rationale is that, if a participant does not have updating activities, it is much more cost-effective to satisfy his or her needs on-demand. The evaluation of CVRetrieval is done in two parts. First, we theoretically analyze the scalability of CVRetrieval and compare it to other consistency maintenance protocols. The analytical result shows that CVRetrieval can greatly reduce communication cost and hence make consistency control more scalable. Second, a prototype of CVRetrieval is developed and deployed on the Planet-Lab test-bed to evaluate its performance. The results show that the active participants experience a short response time at some expense of the passive participants that may encounter a longer response time depends on the system setting. Overall, the retrieval performance is still reasonably high

CVRetrieval: Separating Consistency Retrieval from Consistency Maintenance

In distributed online collaboration applications, such as digital white board and online gaming, it is important to guarantee the consistency among participants’ views to make collaboration meaningful. However, maintaining even a relaxed consistency in a distributed environment with a large number of geographically dispersed participants still involves formidable communication and management cost among them. In this paper, we propose CVRetrieval (Consistency View Retrieval) to solve this scalability problem. Based on the observation that not all participants are equally active or engaged in distributed online collaboration applications, CVRetrieval differentiates the notions of consistency maintenance and consistency retrieval. Here, consistency maintenance implies a protocol that periodically communicates with all participants to maintain a certain consistency level; and consistency retrieval means that passive participants (those with little updating activity) explicitly request a consistent view from the system when the need arises in stead of joining the expensive consistency maintenance protocol all the time. The rationale is that, if a participant does not have updating activities, it is much more cost-effective to satisfy his or her needs on-demand. The evaluation of CVRetrieval is done in two parts. First, we theoretically analyze the scalability of CVRetrieval and compare it to other consistency maintenance protocols. The analytical result shows that CVRetrieval can greatly reduce communication cost and hence make consistency control more scalable. Second, a prototype of CVRetrieval is developed and deployed on the Planet-Lab test-bed to evaluate its performance. The results show that the active participants experience a short response time at some expense of the passive participants that may encounter a longer response time depends on the system setting. Overall, the retrieval performance is still reasonably high

MediaSync: Handbook on Multimedia Synchronization

This book provides an approachable overview of the most recent advances in the fascinating field of media synchronization (mediasync), gathering contributions from the most representative and influential experts. Understanding the challenges of this field in the current multi-sensory, multi-device, and multi-protocol world is not an easy task. The book revisits the foundations of mediasync, including theoretical frameworks and models, highlights ongoing research efforts, like hybrid broadband broadcast (HBB) delivery and users' perception modeling (i.e., Quality of Experience or QoE), and paves the way for the future (e.g., towards the deployment of multi-sensory and ultra-realistic experiences). Although many advances around mediasync have been devised and deployed, this area of research is getting renewed attention to overcome remaining challenges in the next-generation (heterogeneous and ubiquitous) media ecosystem. Given the significant advances in this research area, its current relevance and the multiple disciplines it involves, the availability of a reference book on mediasync becomes necessary. This book fills the gap in this context. In particular, it addresses key aspects and reviews the most relevant contributions within the mediasync research space, from different perspectives. Mediasync: Handbook on Multimedia Synchronization is the perfect companion for scholars and practitioners that want to acquire strong knowledge about this research area, and also approach the challenges behind ensuring the best mediated experiences, by providing the adequate synchronization between the media elements that constitute these experiences