A user-centered approach to network quality of service and charging

The number of network users is expected to triple between 1998 and 2002 (Cullinane, 1998). While a vision of the future Internet offers the potential to break traditional barriers in communications and commerce, the current level of service does not satisfy the requirements of many users (Network Reliability Steering Committee, 1998, Cullinane, 1998). This thesis is concerned with users' perceptions of Quality of Service (QoS), and their attitudes to charging mechanisms applied to wide-area networks. Whilst the majority of research in this area has been conducted from a technical point of view, studies addressing issues of QoS and charging from a users' perspective are limited. The aim of this research was to investigate the latter issue to provide a more complete and integrated perspective on QoS and charging in the user-network system. The thesis first addresses previous work that looks at QoS and charging, establishing a justification for the new research. This part of the thesis concludes that, whilst part of our understanding of QoS requirements can be explained by technical and economic paradigms, additional research is required to examine the perceptions and concomitant behaviour of users. The methodology employed is outlined in relation to obtaining this objective. The second part of the thesis details work undertaken. This work has made the following main contributions: *Developed a set of conceptual models that describe users' perceptions of network QoS. *Shown that these models can be used to predict users' behaviour in different contexts by capturing subjective evaluations of QoS. * Shown how a combination of established and new methods can be successfully applied in capturing and assessing users' perceptions of QoS. *Shown how the new data relates to technical and econometric research. *Provided concrete examples of how the new research can inform network systems design. The work documented in this thesis has implications for user-centred, technical and econometric research. This thesis therefore contributes, not only to the field of HCI to which it is most closely related, but provides guidelines that can be used by econometricians and network designers. The research from all three of these perspectives is concerned with the efficient function of network resource allocation systems. The work documented in this thesis has suggested how it is possible to integrate these perspectives to provide valued levels of QoS to users

Requirements for Internet Quality of Service

perception Growing usage and diversity of applications on the Internet makes Quality of Service (QoS) increasingly critical [15]. To date, the majority of research on QoS is systems oriented, focusing on traffic analysis, scheduling, and routing. Relatively minor attention has been paid to user-level QoS issues. It is not yet known how objective system quality relates to users' subjective perceptions of quality. This paper presents the results of quantitative experiments that establish a mapping between objective and perceived QoS in the context of Internet commerce. We also conducted focus groups to determine how contextual factors influence users ' perceptions of QoS. We show that, while users ' perceptions of World Wide Web QoS are influenced by a number of contextual factors, it is possible to correlate objective measures of QoS with subjective judgements made by users, and therefore influence system design. We argue that only by integrating users ' requirements for QoS into system design can the utility of the future Internet be maximized

Quality is in the eye of the beholder: meeting users’ requirements for internet quality of service

Growing usage and diversity of applications on the Internet makes Quality of Service (QoS) increasingly critical [15]. To date, the majority of research on QoS is systems oriented, lbcusing on traffic analysis, scheduling, and routing. Relatively minor attention has been paid to user-level QoS issues. It is not yet known how objective system quality relates to users ' subjective perceptions of quality. This paper presents the results of quantitative experiments that establish a mapping between objective and perceived QoS in the context of Internet commerce. We also conducted focus groups to determine how contextual lactors influence users ' perceptions of QoS. We show that, while users ' perceptions of World Wide Web QoS are influenced by a number of contextual factors, it is possible to correlate objective measures of QoS with subjective judgements made by users, and therefore influence system design. We argue that only by integrating users' requirements for QoS into system design can the utility of the future Internet be maximized

Integrating UserPerceived Quality into Web Server Design

perception, e

Network Quality of Service - An Integrated Perspective

this paper set out to exam ine w hether the characteristics used to define QoS at the netw ork level m atch the quality requirem ents of those w ho use netw ork applications. Af ter all, users ar

Acknowledgements

I would like first to acknowledge the help and guidance of my supervisor Angela Sasse, who has inspired and encouraged me throughout the period of this research. Her enthusiasm, generosity and friendship are much appreciated. Thanks are also due to Philip Arden, my supervisor at BT Labs, Vicky Hardman, second supervisor at UCL, and Andrew Monk at the University of York for willing assistance and feedback. I am indebted to many UCL colleagues for invaluable contributions to the studies documented in this thesis. Particular thanks go to Ismail Ismail for speaking proper, Orion Hodson for much and patient technical assistance, Colin Perkins for always being there to answer questions, and Yae

Synthesis of ProByFish modelling approach and the effect of TACs for target species on bycatch species

   The ProByFish study was initiated to assist in the development of methods to evaluate the impact of different fisheries management options on the objectives of the Common Fisheries Policy (CFP). The study developed robust methods to a) define target and bycatch species and b) to divide the bycatch species into valuable and collateral bycatch species, the first generally retained on board and landed and the latter generally discarded. The classification of a species depended on the fleet and area in which the fleet operates. The study also identified species which can only sustain low levers of fishing and proceeded to include examples of these in mixed fisheries models.  This report describes the work under the study to analyse of effect of TACs for target species on fishing mortalities of hybrid, valued and collateral bycatch species assuming different management strategies to define TACs for the target species, while no management applies on the bycatch species. The analyses were conducted in a mixed fisheries Management Strategy Evaluation (MSE) framework to examine the probability that single stock TACs are sufficient under natural variability, mixed fishery dynamics and management strategies. The result shows that the effect of changing the species on which to define a TAC are minor compared to the effects concerning the uncertainty around the implementation of the landing obligation.</p