Maximum likelihood estimation for rician distributed data in analytical q-ball imaging

Analytical q-ball imaging is widely used for reconstruction of orientation distribution function (ODF) using diffusion weighted MRI data. Estimating the spherical harmonic coefficients is a critical step in this method. Least squares (LS) is widely used for this purpose assuming the noise to be additive Gaussian. However, Rician noise is considered as a more appropriate model to describe noise in MR signal. Therefore, the current estimation techniques are valid only for high SNRs with Gaussian distribution approximating the Rician distribution. The aim of this study is to present an estimation approach considering the actual distribution of the data to provide reliable results particularly for the case of low SNR values. Maximum likelihood (ML) is investigated as a more effective estimation method. However, no closed form estimator is presented as the estimator becomes nonlinear for the noise assumption of the Rician distribution. Consequently, the results of LS estimator is used as an initial guess and the more refined answer is achieved using iterative numerical methods. According to the results, the ODFs reconstructed from low SNR data are in close agreement with ODFs reconstructed from high SNRs when Rician distribution is considered. Also, the error between the estimated and actual fiber orientations was compared using ML and LS estimator. In low SNRs, ML estimator achieves less error compared to the LS estimator.

S-Kcore : a social-aware Kcore decomposition algorithm in pocket switched networks

The key nodes in network play the critical role in system recovery and survival. Many traditional key nodes selection algorithms utilize the characters of the physical topology to find the key nodes. But they can hardly succeed in the mobile ad hoc network due to the mobility nature of the network. In this paper we propose a social-aware Kcore selection algorithm to work in the Pocket Switched Network. The social view of the network suggests the social position of the mobile nodes can help to find the key nodes in the Pocket Switched Network. The S-Kcore selection algorithm is designed to exploit the nodes' social features to improve the performance in data communication. Experiments use the NS2 shows S-Kcore selection algorithm workable in the Pocket Switched Network. Furthermore, with the social behavior information, those key nodes are more suitable to represent and improve the whole network's performance.

Maximum-likelihood based estimation for Q-ball imaging using diffusion-weighted MRI data

Q-ball imaging has been presented to reconstruct diffusion orientation distribution function using diffusion weighted MRI. In this thesiis, we present a novel and robust approach to satisfy the smoothness constraint required in Q-ball imaging. Moreover, we developed an improved estimator based on the actual distribution of the MR data.

Harajuku : urban stage-set Q & A

Harajuku is arguably one of the most exciting and vibrant fashion precincts of Tokyo. Through a series of questions and answers, Harajuku Urban Stage-Set captures the urban character of the precinct and the complexity of that unique place

Editorial : Q & A John A. Endler

John A. Endler is a Professor of Sensory Ecology and Evolution at Deakin University and an Adjunct professor of Zoology at James Cook University, both in Australia. He regards himself as a 19th century natural historian who uses 21st century techniques to answer questions generated originally from field observations. His research is in the area of overlap among Evolutionary Biology, Sensory Ecology, Behavioural Ecology, Animal Behaviour, Neuroethology and Biophysics. He enjoys combining field work, field experiments, lab work, and theoretical methods as well as constructing electromechanical-optical equipment and software for himself and students.

Evaluation of delivery of the switched on secondary science professional learning (SOSSPL) program

The Switched On Secondary Science Professional Learning (SOSSPL) program consisted of three days professional learning. Days 1 and 2 were undertaken consecutively, with Day 3 following a break of several weeks. The break allowed sufficient time for teachers to undertake a small classroom-based project within one of the topics teachers will be teaching at the time. The program was designed to build teacher capacity to improve learning outcomes in secondary science.

Evaluation of delivery of the switched on secondary science professional learning (SOSSPL) program (2011-12)

The Switched On Secondary Science Professional Learning (SOSSPL) program consisted of three days professional learning for Victorian DEECD secondary science teachers. Days 1 and 2 were undertaken consecutively, with Day 3 following a break of several weeks. The break allowed sufficient time for teachers to undertake a small classroom-based project within one of the topics they were teaching at the time. The program was designed to build teacher capacity to improve student learning outcomes in secondary science.

The program supported teachers to plan and implement classroom sequences that focused on student construction and interpretation of different representations of the science concepts and processes that are described by the Victorian Essential Learning Standards (VELS): Science and the Science Continuum P-10. The Deakin University team in collaboration with the Department of Education and Early Childhood Development (DEECD) produced curriculum resources for the program that encapsulated a representational focus to the teaching and learning of science. The program explored and linked to core DEECD resources such as the e5 Instructional Model and the Science Continuum P-10.
The SOSSPL program was delivered in all Victorian DEECD regions in 2010-11 and was evaluated (Hubber et al, 2011). The program was delivered again in all Victorian DEECD regions in 2011-12. The evaluation of the 2011-12 program is reported here with some comparisons made to the findings from the previously delivered program.
This evaluation of the SOSSPL program involved an online survey, daily workshop evaluations, focus group and presentations data of the participating teachers’ classroom-based projects. The aim of the evaluation was to make a judgement about the effectiveness of the SOSSPL program in terms of building teacher capacity to improve student learning outcomes in secondary science.