Energy-aware peering routing protocol for indoor hospital body area network communication

The recent research in Body Area Networks (BAN) is focused on making its communication more reliable, energy efficient, secure, and to better utilize system resources. In this paper we propose a novel BAN network architecture for indoor hospital environments, and a new mechanism of peer discovery with routing table construction that helps to reduce network traffic load, energy consumption, and improves BAN reliability. We have performed extensive simulations in the Castalia simulation environment to show that our proposed protocol has better performance in terms of reduced BAN traffic load, increased number of successful packets received by nodes, reduced number of packets forwarded by intermediate nodes, and overall lower energy consumption compared to other protocols

Protocols for packet switched communication and reliable multicasting in fully-dynamic multi-hop wireless networks

Designing protocols for a fully dynamic wireless packet switched networks pose unique challenges due to the constantly changing topology of the network. A set of protocols is presented that are capable of handling a fully dynamic wireless network in which switching centers and base stations are mobile as well as the end users. The protocols provide basic message delivery, network routing information updates, and support for reliable multicasting. There are four contributions of this work: (i) a hierarchical architecture for a fully dynamic wireless network, (ii) improved routing and update protocols with reduced control traffic, (iii) a method to provide reliable multicasting in a wireless environment that is near optimal in terms of the number of messages sent, and (iv) a set of load balancing algorithms that allow the network to autonomously and dynamically reconfigure the network topology to even out the load on the base stations. A detailed simulation of the protocols is developed and exercised to evaluate the performance of the protocols. For point to point delivery, the protocols successfully deliver all packets even when the rate of motion of the terminals causes more than 1/2 of them to be in a transitional state at any time. The results are similar for base station

Queueing Networks for Vertical Handover

PhDIt is widely expected that next-generation wireless communication systems will be heterogeneous, integrating a wide variety of wireless access networks. Of particular interest recently is a mix of cellular networks (GSM/GPRS and WCDMA) and wireless local area networks (WLANs) to provide complementary features in terms of coverage, capacity and mobility support. If cellular/ WLAN interworking is to be the basis for a heterogeneous network then the analysis of complex handover traffic rates in the system (especially vertical handover) is one of the most essential issues to be considered. This thesis describes the application of queueing-network theory to the modelling of this heterogeneous wireless overlay system. A network of queues (or queueing network) is a powerful mathematical tool in the performance evaluation of many large-scale engineering systems. It has been used in the modelling of hierarchically structured cellular wireless networks with much success, including queueing network modelling in the study of cellular/ WLAN interworking systems. In the process of queueing network modelling, obtaining the network topology of a system is usually the first step in the construction of a good model, but this topology analysis has never before been used in the handover traffic study in heterogeneous overlay wireless networks. In this thesis, a new topology scheme to facilitate the analysis of handover traffic is proposed. The structural similarity between hierarchical cellular structure and heterogeneous wireless overlay networks is also compared. By replacing the microcells with WLANs in a hierarchical structure, the interworking system is modelled as an open network of Erlang loss systems and with the new topology, the performance measures of blocking probabilities and dropping probabilities can be determined. Both homogeneous and non-homogeneous traffic have been considered, circuit switched and packet-switched. Example scenarios have been used to validate the models, the numerical results showing clear agreement with the known validation scenarios

Mobility Management, Quality of Service, and Security in the Design of Next Generation Wireless Network

The next generation wireless network needs to provide seamless roaming among various access technologies in a heterogeneous environment. In allowing users to access any system at anytime and anywhere, the performance of mobility-enabled protocols is important. While Mobile IPv6 is generally used to support macro-mobility, integrating Mobile IPv6 with Session Initiation Protocol (SIP) to support IP traffic will lead to improved mobility performance. Advanced resource management techniques will ensure Quality of Service (QoS) during real-time mobility within the Next Generation Network (NGN) platform. The techniques may use a QoS Manager to allow end-to-end coordination and adaptation of Quality of Service. The function of the QoS Manager also includes dynamic allocation of resources during handover. Heterogeneous networks raise many challenges in security. A security entity can be configured within the QoS Manager to allow authentication and to maintain trust relationships in order to minimize threats during system handover. The next generation network needs to meet the above requirements of mobility, QoS, and security

Efficient admission control schemes in cellular IP networks

The rapid growth of real-time multimedia applications over IP (Internet Protocol) networks has made the Quality of Service (QoS) a critical issue. One important factor affecting the QoS in the overall IP networks is the admission control in the fast expanding wireless IP networks. Due to the limitations of wireless bandwidth, wireless IP networks (cellular IP networks in particular) are generally considered to be the bottlenecks of the global IP networks. Admission control is to maintain the QoS level for the services admitted. It determines whether to admit or reject a new call request in the mobile cell based on the availability of the bandwidth. In this thesis, the term “call” is for general IP services including voice calls (VoIP) and the term “wireless IP” is used interchangeably with “cellular IP”, which means “cellular or mobile networks supporting IP applications”. In the wireless IP networks, apart from new calls, there are handoff (handover) calls which are calls moving from one cell to another. The general admission control includes the new call admission control and handoff call admission control. The desired admission control schemes should have the QoS maintained in specified levels and network resources (i.e. bandwidth in this case) are utilised efficiently. The study conducted in this thesis is on reviewing current admission control schemes and developing new schemes. Threshold Access Sharing (TAS) scheme is one of the existing schemes with good performance on general call admission. Our work started with enhancing TAS. We have proposed an improved Threshold Access Sharing (iTAS) scheme with the simplified ratebased borrowing which is an adaptive mechanism. The iTAS aims to lower handoff call dropping probability and to maximise the resource utilisation. The scheme works at the cell level (i.e. it is applied at the base station), on the basis of reserving a fixed amount of bandwidth for handoff calls. Prioritised calls can be admitted by “borrowing” bandwidth from other ongoing calls. Our simulation has shown that the new scheme has outperformed the original TAS in terms of handoff prioritisation and handling, especially for bandwidth adaptive calls. However, in iTAS, the admission decision is made solely based on bandwidth related criteria. All calls of same class are assumed having similar behaviour. In the real situation, many factors can be referred in decision making of the admission control, especially the handoff call handling. We have proposed a novice scheme, which considered multiple criteria with different weights. The total weights are used to make a decision for a handoff. These criteria are hard to be modelled in the traditional admission models. Our simulated result has demonstrated that this scheme yields better performance in terms of handoff call xiv dropping compared with iTAS. We further expand the coverage of the admission control from a cell level to a system level in the hierarchical networks. A new admission control model was built, aiming to optimise bandwidth utilisation by separating the signalling channels and traffic channels in different tiers. In the new model, handoff calls are also prioritised using call classification and admission levels. Calls belonging to a certain class follow a pre-defined admission rule. The admission levels can be adjusted to suit the traffic situation in the system. Our simulated results show that this model works better than the normal 2-tier hierarchical networks in terms of handoff calls. The model settings are adjustable to reflect real situation. Finally we conclude our research and suggest some possible future work

Tackling Ageing Continence through Theory, Tools & Technology

Originally presented at ‘Aging and Society: An Interdisciplinary Conference’, University of California, Berkeley (2011), this article was double-blind peer reviewed, receiving scores of 96% and 73%. It outlines the interdisciplinary research of the cross-Research-Council-funded New Dynamics of Ageing Tackling Ageing Continence through Theory Tools & Technology (TACT3) project (2008–12), which brought together designers, social scientists, bio-engineers, chemists and care-management services to understand the challenges faced by an ageing population in the management of continence. Bichard’s Work Package, ‘Challenging Environmental Barriers to Continence’, explored the need for public toilet provision as essential for quality of life, health and well-being. It developed a life-course methodology that considered ageing from birth through to advanced age (0–101 years), and involved inclusive design research with members of the public and providers of facilities to assess public expectations and provider limitations in service provision. As co-investigator on TACT3, this research built on Bichard’s previous work for the VivaCity2020 consortium (Bichard REF Output 2). Whereas the VivaCity2020 work focused on architectural barriers in toilet provision, the TACT3 project examined the problem in service provision, and how, through inclusive design research, service-design solutions might be explored and implemented. Bichard’s contribution to the TACT3 project produced The Great British Public Toilet Map (http://greatbritishpublictoiletmap.rca.ac.uk/), a public participation website that provides information and locations of public toilets, encouraging members of the public to contact relevant local authorities that have not released information in the format of Open Data. Secondary analysis of TACT3 data for references to issues of personal safety and community initiative in toilet provision was used for the ESRC-funded Robust Accessible Toilets (RATs) project (2011) and produced Publicly Accessible Toilets: An Inclusive Design Guide (2011). Related published conference papers include those in ‘Cumulus 2010’ (China) and ‘Include 2011’ (UK)

Time-Resolved Transcriptome Analysis of Bacillus subtilis Responding to Valine, Glutamate, and Glutamine

Microorganisms can restructure their transcriptional output to adapt to environmental conditions by sensing endogenous metabolite pools. In this paper, an Agilent customized microarray representing 4,106 genes was used to study temporal transcript profiles of Bacillus subtilis in response to valine, glutamate and glutamine pulses over 24 h. A total of 673, 835, and 1135 amino-acid-regulated genes were identified having significantly changed expression at one or more time points in response to valine, glutamate, and glutamine, respectively, including genes involved in cell wall, cellular import, metabolism of amino-acids and nucleotides, transcriptional regulation, flagellar motility, chemotaxis, phage proteins, sporulation, and many genes of unknown function. Different amino acid treatments were compared in terms of both the global temporal profiles and the 5-minute quick regulations, and between-experiment differential genes were identified. The highlighted genes were analyzed based on diverse sources of gene functions using a variety of computational tools, including T-profiler analysis, and hierarchical clustering. The results revealed the common and distinct modes of action of these three amino acids, and should help to elucidate the specific signaling mechanism of each amino acid as an effector