Anonymous network access using the digital marketplace

With increasing usage of mobile telephony, and the trend towards additional mobile Internet usage, privacy and anonymity become more and more important. Previously-published anonymous communication schemes aim to obscure their users' network addresses, because real-world identity can be easily be derived from this information. We propose modifications to a novel call-management architecture, the digital marketplace, which will break this link, therefore enabling truly anonymous network access

The DSN programming system

The Deep Space Network programming system is described by a heuristic model. Interaction with two elements of that system, anomaly reporting and the MBASIC (trademark) language, is described in detail. Feedback from anomaly reporting indicates that the methodology resulted in a low anomaly rate and thereby also provided positive feedback. The need to reduce operating costs prompted the implementation of the MBASIC (trademark) language as a compiler

Management system requirements for wireless systems beyond 3G

This paper presents a comprehensive description of various management system requirements for systems beyond 3G, which have been identified as a result of the Software Based Systems activities within the Mobile VCE Core 2 program. Specific requirements for systems beyond 3G are discussed and potential technologies to address them proposed. The analysis has been carried out from network, service and security viewpoints

Molecular dynamics simulations of protein-membrane interactions focusing on PI3Kα and its oncogenic mutants : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Computational Biochemistry at Massey University, Albany, New Zealand

The interactions between proteins and membranes are key to many aspects of biological function. Molecular dynamics simulations can provide insight into both atomic-level structural details and energetics of protein-membrane interactions. This thesis describes the development of a physiologically accurate brain lipid bilayer, and its use in molecular dynamics simulations to characterise how proteins that are important drug targets interact with the cell membrane. A method for rapidly identifying the orientation of a protein that interacts most favourably with a membrane was also developed and tested. The first chapter provides an introduction to molecular dynamics and its role in the context of this research. The second chapter details the development of a cellular membrane with a physiologically representative brain lipid composition. This was done through the testing of simple systems prior to the construction of two more complex lipid bilayers comprising phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositide 4,5 bisphosphate (PIP2), sphingomyelin, and cholesterol. The third chapter implements the brain lipid bilayer in the development of a rotational interaction energy screening method designed to predict the most favourable orientation of a protein with respect to the cellular membrane. The functionality of the method was validated through application to two membrane proteins commonly implicated in cancer: the phosphatase and tensin homolog (PTEN), and the p110α-p85α phosphatidyl-inositol kinase (PI3Kα) complex. The fourth chapter corresponds to the main focus of this research, the behaviour of wild type PI3Kα and two of its oncogenic mutants (E545K and H1047R) with regards to membrane and substrate interaction. It was primarily found that H1047R’s increased membrane affinity allowed it to sample a catalytically competent orientation independently of Ras, unlike the wild type. Furthermore, it was also found that the position of the C terminal tail with regards to the substrate binding pocket was crucial in the achievement of a catalytically competent position against the cellular membrane. The fifth and final chapter describes a cytochrome P450 system embedded in a cellular membrane. It was primarily found that the properties of its ingress and egress tunnels depended on the presence or absence of a substrate in the active site

Coulomb Oscillations of Indium-doped ZnO Nanowire Transistors in a Magnetic Field

We report on the observation of Coulomb oscillations from localized quantum dots superimposed on the normal hopping current in ZnO nanowire transistors. The Coulomb oscillations can be resolved up to 20 K. Positive anisotropic magnetoresistance has been observed due to the Lorentz force on the carrier motion. Magnetic field-induced tunneling barrier transparency results in an increase of oscillation amplitude with increasing magnetic field. The energy shift as a function of magnetic field indicates electron wavefunction modification in the quantum dots.Comment: 16 pages, 6 figure

The Euclid-Mullin graph

We introduce the Euclid-Mullin graph, which encodes all instances of Euclid's proof of the infinitude of primes. We investigate structural properties of the graph both theoretically and numerically; in particular, we prove that it is not a tree.Comment: 24 pages, 2 figures, to appear in Journal of Number Theor

Mobile distributed authentication protocol

Networks access control is a crucial topic and authentication is a pre-requisite of that process. Most existing authentication protocols (for example that used in the GSM mobile network) are centralised. Depending on a single entity is undesirable as it has security, trust and availability issues. This paper proposes a new protocol, GSM-secure network access protocol (G-SNAP). In G-SNAP, the authentication procedure and network access control is handled by a quorum of authentication centres. The advantages of the novel protocol include increased security, availability and distributed trust