Nonnegative Blind Source Separation by Sparse Component Analysis Based on Determinant Measure

The problem of nonnegative blind source separation (NBSS) is addressed in this paper, where both the sources and the mixing matrix are nonnegative. Because many real-world signals are sparse, we deal with NBSS by sparse component analysis. First, a determinant-based sparseness measure, named D-measure, is introduced to gauge the temporal and spatial sparseness of signals. Based on this measure, a new NBSS model is derived, and an iterative sparseness maximization (ISM) approach is proposed to solve this model. In the ISM approach, the NBSS problem can be cast into row-to-row optimizations with respect to the unmixing matrix, and then the quadratic programming (QP) technique is used to optimize each row. Furthermore, we analyze the source identifiability and the computational complexity of the proposed ISM-QP method. The new method requires relatively weak conditions on the sources and the mixing matrix, has high computational efficiency, and is easy to implement. Simulation results demonstrate the effectiveness of our method.

Having the courage to measure up for education

In this “age of measurement” it is increasing difficult for educators to educate (Biesta, 2010). The pressures to conform to the demands of bureaucratic authorities generally trump over educators and their aims to educate. One of the factors contributing to this is because as Dewey (1929a, p. 133) has argued, our aims and our desires to educate don’t have deep enough roots. He suggests that educators ought to have “cultivated” and “significant conscious desires” and a disposition to be “courageous” (1929a, p. 134; 1929b, p. 38) in order to attain the independence to ensure that our practices in education are indeed educational. Dewey (1934) called such a disposition a “religious attitude” because it engages with the ultimate concerns that people can aspire towards. In this paper I shall argue that this religious attitude of Dewey’s which can enable our roots to deepen, does not just pertain to our aims of education as an intellectual phenomenon. Rather it can be understood as existential (Webster, 2009) in the sense that aims of education are specific to individuals in situation – not to abstract or universal understandings of education. It shall also be argued that this existential aspect of our being is emotive, and deepening its roots might enable us to become more courageous and thus more able to challenge the barriers inherent in our current ‘age of measurement’ so that education may become more of a reality.

Aussie leads project to measure Iraq’s heritage destruction

A Melbourne academic is leading a very different battle in Iraq: an attempt to restore as much as possible of the country's ransacked cultural heritage.

Validity of an upper-body-mounted accelerometer to measure peak vertical and resultant force during running and change-of-direction tasks

This study assessed the validity of a tri-axial accelerometer worn on the upper body to estimate peak forces during running and change-of-direction tasks. Seventeen participants completed four different running and change-of-direction tasks (0°, 45°, 90°, and 180°; five trials per condition). Peak crania-caudal and resultant acceleration was converted to force and compared against peak force plate ground reaction force (GRF) in two formats (raw and smoothed). The resultant smoothed (10 Hz) and crania-caudal raw (except 180°) accelerometer values were not significantly different to resultant and vertical GRF for all running and change-of-direction tasks, respectively. Resultant accelerometer measures showed no to strong significant correlations (r = 0.00–0.76) and moderate to large measurement errors (coefficient of variation [CV] = 11.7–23.9%). Crania-caudal accelerometer measures showed small to moderate correlations (r = − 0.26 to 0.39) and moderate to large measurement errors (CV = 15.0–20.6%). Accelerometers, within integrated micro-technology tracking devices and worn on the upper body, can provide a relative measure of peak impact force experienced during running and two change-of-direction tasks (45° and 90°) provided that resultant smoothed values are used.

The rapid assessment of disability – informing the development of an instrument to measure the effectiveness of disability inclusive development through a qualitative study in Bangladesh

Purpose
The Rapid Assessment of Disability (RAD) questionnaire was developed to provide governments and development agencies with an appropriate instrument to determine the prevalence of people with disability within their target populations, and to design and evaluate the effectiveness of disability inclusive activities in addressing their priorities and needs.
Methods
The RAD questionnaire was developed using two conceptual frameworks: the United Nations Convention on the Rights of Persons with Disabilities (UNCRPD), and the International Classification of Functioning, Disability and Health (ICF). Existing instruments were reviewed to inform the structure and content of the RAD questionnaire. The RAD questionnaire that was developed for field testing in Bangladesh comprised both a household questionnaire and a questionnaire for individuals within each household, with 5 sections: 1) Demographic information, 2) Assessment of functioning, 3) Awareness of rights of people with disability, 4) Well-being and quality of life, 5) Participation in the community.
Prior to field-testing the RAD questionnaire in Bangladesh, a qualitative study was conducted to ensure the relevance of the questionnaire in the context of a developing country. In-depth interviews with 9 people with disability and a focus group of 8 parents of children with disability were conducted in Dhaka, Bangladesh.
Results
Qualitative findings highlighted factors relevant to the lives of people with disability in Bangladesh, including discrepancies between the awareness and attainment of rights for people with disability, the wellbeing of people with disability and their families, as well as numerous barriers to full participation in their community. While the findings confirmed that the design and content of the questionnaire reflected all these aspects, some changes were made to the items in the questionnaire to ensure that it reflected the views of people with disability from the context of a developing country.
Conclusions and Implications
This qualitative study was an important step in the development of the RAD questionnaire as it helped to achieve its aim - namely, to establish the prevalence of disability and to assist in the design and evaluation of disability inclusive interventions in the setting of a developing country.

Performance of the assessment of quality of life measure in people with hip and knee joint disease and implications for research and clinical use

Objective
To comprehensively evaluate the performance of the Assessment of Quality of Life (AQoL) instrument for measuring health-related quality of life (HRQOL) in people with hip and knee joint disease (arthritis or osteoarthritis).

Methods
Data from 237 individuals were available for analysis from a national cross-sectional, population-based study of hip and knee joint disease in Australia. AQoL-4D data were evaluated using Rasch analysis. A range of measurement properties was explored, including model and item fit, threshold ordering, differential item functioning, and targeting.

Results
Good overall fit of the AQoL with the Rasch model was demonstrated across a range of tests, supporting internal validity. Only 1 item (relating to hearing) showed evidence of misfit. Most AQoL items showed logical sequencing of response option categories, with threshold disordering evident for only 2 of the 12 items (items 4 and 9). Minor issues with potential clinical and research implications include limited options for reporting pain and some evidence of measurement bias between demographic subgroups (including age and sex). Participants' HRQOL was generally better than that represented by the AQoL items (mean ± SD for person abilities −2.15 ± 1.39, mean ± SD for item difficulties 0.00 ± 0.67), indicating ceiling effects that could impact the instrument's ability to detect HRQOL improvement in population-based studies.

Conclusion
The AQoL is a competent tool for assessing HRQOL in people with hip and knee joint disease, although researchers and clinicians should consider the caveats identified when selecting appropriate HRQOL measures for future outcome assessment involving this patient group.

Software similarity and classification

This thesis analyses software programs in the context of their similarity to other software programs. Applications proposed and implemented include detecting malicious software and discovering security vulnerabilities.