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This paper describes the user interface design, and subsequent usability evaluation of the EU FP6 funded Easyline+ project, which involved the development of ambient assistive technology to support elderly and disabled people in their interaction with kitchen appliances. During this process, established usability design guidelines and principles were considered. The authors’ analysis of the applicability of these has led to the development of a new set of principles, specifically for the design of ambient computer systems. This set of principles is referred to as SCUFF, an acronym for simplicity, consistency, universality, flexibility and familiarity. These evaluations suggest that adoption of the SCUFF principles was successful for the Easyline+ project, and that they can be used for other ambient technology projects, either as complementary to, or as an alternative to more generic and partially relevant principles.

In this paper, we present a case study on the development of interfaces for elderly and disabled users. The domain of the case study was situated in the home environment, where we focused on producing affordable technologies to enable users to interact with and to control home appliances. We have developed ambient user interfaces that are integrated in familiar home artefacts, such as televisions and digital picture frames. These interfaces are connected remotely to a home network and are adaptive to users’ expected increasing physical and cognitive needs. To support the development of the project, we created a novel methodology that is grounded in the ethical issues associated with a project of this nature. Our success with it has led to us presenting it here as a practical approach to developing user interfaces for a range of interactive applications, especially where there may be diverse user populations. This paper describes our journey through this project, how the methodology has been used throughout and the development of our user interfaces and their evaluation.

This paper considers various forms of objective function that may be applied in the calculation of spanning trees in different network situations. Conventional link and path cost approaches are compared to those based on switch or bridge costs more appropriate for wireless applications. Variant objectives are formulated and compared. Although efficient exact algorithmic approaches exist only for the link cost objectives, reasonable approximations for the switch/bridge equivalents are to be found with simple greedy heuristics and better results still through various forms of iterated local search such as tabu search and simulated annealing.

In this paper, I take an overview of the convergence between psychology and game design, particularly the use of intrinsic and extrinsic rewards in game design.

There is a tendency to overlook or play down software issues in industrial systems design. However the very best hardware will only be as effective as the programs that control it. The search for a software solution to a problem should not stop with the discovery of the first approach that works, or appears to work. Many problems support good and bad methods of solution and determining the best often requires deeper consideration. In this paper we present some rudimentary introductions and examples of common computational challenges. We aim to highlight key issues for consideration when implementing control systems which otherwise might be unintentionally overlooked.

This paper presents a modelling and simulation framework for analysing Access Control List (ACL) implementation on Internet devices. It uses the established modelling/simulation techniques of abstraction and simplification to isolate the essential components of the system from peripheral issues. As a case study, the viability of a simple real-time optimisation technique is demonstrated.

Long-range dependence characteristics have been observed in many natural or physical phenomena. In particular, a significant impact on data network performance has been shown in several papers. Congested Internet situations, where TCP/IP buffers start to fill, show long-range dependent (LRD) self-similar chaotic behaviour. The exponential growth of the number of servers, as well as the number of users, causes the performance of the Internet to be problematic since the LRD traffic has a significant impact on the buffer requirements. The Internet is a large-scale, wide-area network for which the importance of measurement and analysis of traffic is vital. The intensity of the long-range dependence (LRD) of communications network traffic can be measured using the Hurst parameter. A variety of techniques (such as R/S analysis, aggregated variance-time analysis, periodogram analysis, Whittle estimator, Higuchi's method, wavelet-based estimator, absolute moment method, etc.) exist for estimating Hurst exponent but the accuracy of the estimation is still a complicated and controversial issue. Earlier research (Rezaul et al., 2006) introduced a novel estimator called the Hurst exponent from the autocorrelation function (HEAF) and it was shown why lag 2 in HEAF (i.e. HEAF (2)) is considered when estimating LRD of network traffic. HEAF estimates H by a process which is simple, quick and reliable. In this research we extend these concepts by introducing a novel algorithm for controlling the long-range dependence of network traffic, named CoLoRaDe which is shown to reduce the LRD of packet sequences at the router buffer.

Sensor mesh networking is set to be one of the key tools for the future of Ambient Intelligence (AmI) due to new emerging technologies in Ad hoc Wireless Sensor Networks (AWSNs). AWSNs symbolize the new generation of sensor networks with many promising advantages applicable to most networked environments. Unfortunately, however, these practical technologies have some technical problems and, as a consequence, this fascinating field has created novel and interesting challenges, which in turn, have inspired many ongoing research projects and more are likely to follow. Almost certainly, there will be notable improvements in the management of control/actuator networks as a consequence of enhancing the sensitivity capabilities of systems. With an emphasis on Ad hoc Wireless Sensor Actuator Networks (AWSANs) this study presents a systematic analysis of the different existing techniques to improve such systems. It also discusses, analyzes and summarizes the advantages these technologies offer in certain applications and presents a generic solution, in the form of a case study, for an AmI system to enhance the overall environmental management of a campus based on a hierarchical network using an AWSAN.

This paper generalises and strengthens the investigation of capturing intangible data for the benefit of organisations encouraging learning environments and self-organisation practices. It suggests current technological and algorithmic analysis may aid an organisation’s quest for sustained competitive advantage through the identification of previously unobservable data including cultural nuances. However, the implementation of such an approach presents challenges of which we summarise in our conclusion.

This paper presents three case studies in network design and management from the different, but often overlapping and blurred, perspectives of the theorist and practitioner. It addresses the gulf between the comfortable models of graph theory, statistics and suchlike and the harsh realities of real-world networks. As, through these case studies, it becomes evident that network techniques, algorithms, etc. at large in the Internet bear little resemblance to their counterparts in the textbooks, the question is posed (and partially answered) as to whether the original theory is really any use!

Among the various options for implementing Internet packet filters in the form of Access Control Lists (ACLs), is the intuitive – but potentially crude – method of processing the ACL rules in sequential order. Although such an approach leads to variable processing times for each packet matched against the ACL, it also offers the opportunity to reduce this time by reordering its rules in response to changing traffic characteristics. A number of heuristics exist for optimising rule order in sequentially processed ACLs and the most efficient of these can be shown to have a beneficial effect in a majority of cases and for ACLs with relatively small numbers of rules. This paper presents an enhancement to this algorithm by reducing part of its complexity. Although the simplification involved leads to an instantaneous lack of accuracy, the long-term trade-off between processing speed and performance can be seen, through experimentation, to be positive. This improvement, though small, is consistent and worthwhile and can be observed in the majority of cases.

This paper presents issues relating to information and musical content dealt with as part of the development of an innovative audio compression system, designed to exploit repetition sequences in audio, and particularly, music. The paper briefly introduces and describes how musical content and structure within audio can be exploited to achieve compression. A new system to take advantage of these hypotheses is described. The paper introduces a new file format to deal with high-level data chunks and repetitive structuring. The practicalities of searching for large blocks of audio data are discussed and evidence provided of the high amounts of complexity involved in performing brute-force searches for self-similar matching. This high complexity is the subject of current work by the authors and research to date so far reveals that search time can be reduced by considering content analysis, this time to reduce complexity rather than data volume.

The Maximum Bandwidth Path Algorithm (MBPA) is introduced as an alternative to Dijkstra’s Shortest Path Algorithm (DSPA) for Internet routing. The two are compared and differences noted. Of particular interest is the extent to which each algorithm achieves Implicit Load Balancing (ILB) – the principle of effective link usage for traffic across the network as a whole for non-equal paths and without the use of explicit routing variance. Although MBPA may prove to be more efficient than DSPA generally (further work is required), it is shown, through extensive simulation, that it produces better levels of ILB for real, as opposed to artificial, network scenarios.

The infrastructure of large networks is broken down into areas that have a common security policy called a domain. Security within a domain is commonly implemented at all nodes however this has a negative effect on performance since it introduces a delay associated with packet filtering. Recommended techniques for network design imply that every packet should be checked at the first possible ingress points of the network. When access control lists (ACL's) are used within a router for this purpose then there can be a significant overhead associated with this process. The purpose of this paper is to consider the effect of delays when using router operating systems offering different levels of functionality. It considers factors which contribute to the delay particularly due to ACL. Using theoretical principles modified by practical calculation a model is created for packet delay for all nodes across a given path in a domain.

With the increase in the provision of access to Wireless Local Area Networks and the abundance of user devices capable of utilising Wi-Fi, the design of the network infrastructure has introduced some significant problems. Prior to the installation of Access Points it is difficult to predict whether access can be guaranteed at specific locations. Additionally, to increase the level of security, it is often preferable, despite the use of security protocols, to ensure that the signal strength is not large enough to enable connection in areas other than those designated. By combining the theory of antennae and the measurement of the performance of devices, it is possible to predict whether access is likely and hence how secure the network design is. Additionally, the use of a simple application is proposed that enables the network designer to enter a configuration and produce an answer showing if WIFI will operate and a value to indicate the margin.

This paper introduces two new algorithms for the minimum connected dominating set problem. The problem and its relevance to various aspects of wireless network optimisation are briefly outlined followed by a description of the suggested techniques. Results show that these algorithms outperform a number of previous approaches in terms of solution quality and potential for future work is discussed.