Virtual numbers for virtual machines?

Knowing the number of virtual machines (VMs) that a cloud physical hardware can (further) support is critical as it has implications on provisioning and hardware procurement. However, current methods for estimating the maximum number of VMs possible on a given hardware is usually the ratio of the specifications of a VM to the underlying cloud hardware’s specifications. Such naive and linear estimation methods mostly yield impractical limits as to how many VMs the hardware can actually support. It was found that if we base on the naive division method, user experience on VMs at those limits would be severely degraded. In this paper, we demonstrate through experimental results, the significant gap between the limits derived using the estimation method mentioned above and the actual situation. We believe for a more practicable estimation of the limits of the underlying infrastructure

Development of Metal Halide Perovskites for Radiation Detection

Metal halide perovskite (MHP) semiconductors have attracted significant interest in recent years within photovoltaic and radiation detection communities due to their inexpensive solution growths, high effective atomic number for gamma and X-ray sensing, suitable bandgap, large resistivity, and moderate mobility-lifetime products. The MHP stoichiometry can also be tuned as needed to achieve desired physical and electronic properties. Moreover, the hybrid or organometallic halide perovskite (OMHP) variants contain a large atomic fraction of hydrogen for fast neutron sensing. These qualities make MHPs an attractive low-cost option for meeting detector needs within nuclear security and imaging applications. This work presents the development of MHPs for radiation sensing, with the majority of the results pertaining to a specific OMHP variant, methylammonium lead tribromide (CH3NH3PbBr3, MAPbBr3, or MAPB). The implementation of birefringence screening, chemomechanical polishing, and tin oxide electrode designs as improvements to the detector fabrication process are demonstrated, followed by benchmarking of the charge transport properties through alpha particle irradiation, X-ray induced photocurrents, and deconvolution of preamplifier signals. Notable achievements in radiation sensing are then presented, including X-ray imaging with MAPB, the development of a bi-parametric program to improve gamma ray sensing, and thermal neutron sensing with lithium-doped MAPB. Finally, the negative effects of radiation damage on the performance of MHP devices are demonstrated, followed by the evaluation of annealing and low temperature testing as strategies to mitigate detector degradations over time and improve radiation detection performance. Although certain challenges remain to minimize physical and electronic defects to improve detector stability and charge transport properties, the methods and findings presented in this thesis demonstrate the potential for MHP radiation sensors to meet detector requirements within nuclear security and imaging applications

Time for Cloud? Design and implementation of a time-based cloud resource management system

The current pay-per-use model adopted by public cloud service providers has influenced the perception on how a cloud should provide its resources to end-users, i.e. on-demand and access to an unlimited amount of resources. However, not all clouds are equal. While such provisioning models work for well-endowed public clouds, they may not always work well in private clouds with limited budget and resources such as research and education clouds. Private clouds also stand to be impacted greatly by issues such as user resource hogging and the misuse of resources for nefarious activities. These problems are usually caused by challenges such as (1) limited physical servers/ budget, (2) growing number of users and (3) the inability to gracefully and automatically relinquish resources from inactive users. Currently, cloud resource management frameworks used for private cloud setups, such as OpenStack and CloudStack, only uses the pay-per-use model as the basis when provisioning resources to users. In this paper, we propose OpenStack Café, a novel methodology adopting the concepts of 'time' and booking systems' to manage resources of private clouds. By allowing users to book resources over specific time-slots, our proposed solution can efficiently and automatically help administrators manage users' access to resource, addressing the issue of resource hogging and gracefully relinquish resources back to the pool in resource-constrained private cloud setups. Work is currently in progress to adopt Café into OpenStack as a feature, and results of our prototype show promises. We also present some insights to lessons learnt during the design and implementation of our proposed methodology in this paper

A composition theorem for parity kill number

In this work, we study the parity complexity measures ${\mathsf{C}^{\oplus}_{\min}}[f]$ and ${\mathsf{DT^{\oplus}}}[f]$. ${\mathsf{C}^{\oplus}_{\min}}[f]$ is the \emph{parity kill number} of $f$, the fewest number of parities on the input variables one has to fix in order to "kill" $f$, i.e. to make it constant. ${\mathsf{DT^{\oplus}}}[f]$ is the depth of the shortest \emph{parity decision tree} which computes $f$. These complexity measures have in recent years become increasingly important in the fields of communication complexity \cite{ZS09, MO09, ZS10, TWXZ13} and pseudorandomness \cite{BK12, Sha11, CT13}. Our main result is a composition theorem for ${\mathsf{C}^{\oplus}_{\min}}$. The $k$-th power of $f$, denoted $f^{\circ k}$, is the function which results from composing $f$ with itself $k$ times. We prove that if $f$ is not a parity function, then ${\mathsf{C}^{\oplus}_{\min}}[f^{\circ k}] \geq \Omega({\mathsf{C}_{\min}}[f]^{k}).$ In other words, the parity kill number of $f$ is essentially supermultiplicative in the \emph{normal} kill number of $f$ (also known as the minimum certificate complexity). As an application of our composition theorem, we show lower bounds on the parity complexity measures of $\mathsf{Sort}^{\circ k}$ and $\mathsf{HI}^{\circ k}$. Here $\mathsf{Sort}$ is the sort function due to Ambainis \cite{Amb06}, and $\mathsf{HI}$ is Kushilevitz's hemi-icosahedron function \cite{NW95}. In doing so, we disprove a conjecture of Montanaro and Osborne \cite{MO09} which had applications to communication complexity and computational learning theory. In addition, we give new lower bounds for conjectures of \cite{MO09,ZS10} and \cite{TWXZ13}

Public value summary background paper

The Australian Centre of Excellence for Local Government (ACELG) at UTS has published a background paper about understanding and promoting public value creation within Australian local government. The paper provides a definition of public value and public value creation from key literature, and links this with current practice within the sector. The Public Value project is a partnership between the Local Government Business Excellence Network (LGBEN) and ACELG and explores how councils create public value in a broad sense – or ‘the common good’ – and deliver this value specifically through planning and managing and delivering a wide range of services, programs and projects. A final phase of the project will provide examples of public value so frameworks and tools can be developed for councils looking at undertaking continual improvement initiatives

Towards Quantifying Complexity with Quantum Mechanics

While we have intuitive notions of structure and complexity, the formalization of this intuition is non-trivial. The statistical complexity is a popular candidate. It is based on the idea that the complexity of a process can be quantified by the complexity of its simplest mathematical model - the model that requires the least past information for optimal future prediction. Here we review how such models, known as $\epsilon$-machines can be further simplified through quantum logic, and explore the resulting consequences for understanding complexity. In particular, we propose a new measure of complexity based on quantum $\epsilon$-machines. We apply this to a simple system undergoing constant thermalization. The resulting quantum measure of complexity aligns more closely with our intuition of how complexity should behave.Comment: 10 pages, 6 figure, Published in the Focus Point on Quantum information and complexity edition of EPJ Plu

How council mergers and reforms imperil local government democracy

Australia’s local government sector has been undergoing reform in recent decades. The result has been fewer and larger local governments and a reshaped role for elected members or councillors. But do councillors understand what this means for them

Editorial

The Commonwealth Journal of Local Governance is now co-edited and has a new look. Under the continued editorship of Prof. Alison Brown, the Centre for Local Government at the University of Technology, Sydney is pleased to partner with Cardiff University and the Commonwealth Local Government Forum (CLGF) to produce the journal. This new partnership will ensure the continued development of the journal as an important platform for local government researchers and practitioners to share knowledge and experience