Characteristics of ultrafine particle sources and deposition rates in primary school classrooms

The aim of this work was to investigate changes in particle number concentration (PNC) within naturally ventilated primary school classrooms arising from local sources either within or adjacent to the classrooms. We quantify the rate at which ultrafine particles were emitted either from printing, grilling, heating or cleaning activities and the rate at which the particles were removed by both deposition and air exchange processes. At each of 25 schools in Brisbane, Australia, two weeks of measurements of PNC and CO2 were taken both outdoors and in the two classrooms. Bayesian regression modelling was employed in order to estimate the relevant rates and analyse the relationship between air exchange rate (AER), particle infiltration and the deposition rates of particle generated from indoor activities in the classrooms. During schooling hours, grilling events at the school tuckshop as well as heating and printing in the classrooms led to indoor PNCs being elevated by a factor of more than four, with emission rates of (2.51 ± 0.25) x 1011 p min-1, (8.99 ± 6.70) x 1011 p min-1 and (5.17 ± 2.00) x 1011 p min-1, respectively. During non-school hours, cleaning events elevated indoor PNC by a factor of above five, with an average emission rate of (2.09 ± 6.30) x 1011 p min-1. Particles were removed by both air exchange and deposition; chiefly by ventilation when AER > 0.7 h-1 and by deposition when AER < 0.7 h-1.

The economics of credence goods : an experiment on the role of liability, verifiability, reputation and competition

Credence goods markets are characterized by asymmetric information between sellers and consumers that may give rise to inefficiencies, such as under- and overtreatment or market breakdown. We study in a large experiment with 936 participants the determinants for efficiency in credence goods markets. While theory predicts that liability or verifiability yield efficiency, we find that liability has a crucial, but verifiability at best a minor, effect. Allowing sellers to build up reputation has little influence, as predicted. Seller competition drives down prices and yields maximal trade, but does not lead to higher efficiency as long as liability is violated. (JEL D12, D82)

Competition policy review : draft recommendations on competition laws

On 4 December 2013, the Prime Minister and the Minister for Small Business announced a “root and branch” review of Australia’s competition policy. The Minister for Small Business released the final Terms of Reference for the competition policy review on 27 March 2014, following consultation with the States and Territories, and announced the Review Panel headed by Professor Ian Harper. Under the terms of reference the Competition Policy Review Committee (the Harper Committee) is required to focus on three broad areas: •examining what can be done to create more competition in service areas such as health, education and intellectual property; •considering whether the structure and powers of the competition institutions (the ACCC , the NCC, the Tribunal and the AER) remain appropriate; and •examining the effectiveness of the competition provisions of the Competition and Consumer Act 2010 (Cth) (CCA) and laying down a broad framework through which the law can be streamlined and reformed over time.

A cluster-voting approach for speaker diarization and linking of Australian broadcast news recordings

We present a clustering-only approach to the problem of speaker diarization to eliminate the need for the commonly employed and computationally expensive Viterbi segmentation and realignment stage. We use multiple linear segmentations of a recording and carry out complete-linkage clustering within each segmentation scenario to obtain a set of clustering decisions for each case. We then collect all clustering decisions, across all cases, to compute a pairwise vote between the segments and conduct complete-linkage clustering to cluster them at a resolution equal to the minimum segment length used in the linear segmentations. We use our proposed cluster-voting approach to carry out speaker diarization and linking across the SAIVT-BNEWS corpus of Australian broadcast news data. We compare our technique to an equivalent baseline system with Viterbi realignment and show that our approach can outperform the baseline technique with respect to the diarization error rate (DER) and attribution error rate (AER).