Relating Objective and Subjective Performance Measures for AAM-based Visual Speech Synthesizers

We compare two approaches for synthesizing visual speech using Active Appearance Models (AAMs): one that utilizes acoustic features as input, and one that utilizes a phonetic transcription as input. Both synthesizers are trained using the same data and the performance is measured using both objective and subjective testing. We investigate the impact of likely sources of error in the synthesized visual speech by introducing typical errors into real visual speech sequences and subjectively measuring the perceived degradation. When only a small region (e.g. a single syllable) of ground-truth visual speech is incorrect we find that the subjective score for the entire sequence is subjectively lower than sequences generated by our synthesizers. This observation motivates further consideration of an often ignored issue, which is to what extent are subjective measures correlated with objective measures of performance? Significantly, we find that the most commonly used objective measures of performance are not necessarily the best indicator of viewer perception of quality. We empirically evaluate alternatives and show that the cost of a dynamic time warp of synthesized visual speech parameters to the respective ground-truth parameters is a better indicator of subjective quality

The Nonlinear Debye-Onsager Relaxation Effect in Weakly Ionized Plasmas

A weakly ionized plasma under the influence of a strong electric field is considered. Supposing a local Maxwellian distribution for the electron momenta the plasma is described by hydrodynamic equations for the pair distribution functions. These equations are solved and the relaxation field is calculated for an arbitrary field strength. It is found that the relaxation effect becomes lower with increasing strength of the electrical field.Comment: 4 pages, 1 figur

Indicators of sustainable capacity building for health research: analysis of four African case studies

<p>Abstract</p> <p>Background</p> <p>Despite substantial investment in health capacity building in developing countries, evaluations of capacity building effectiveness are scarce. By analysing projects in Africa that had successfully built sustainable capacity, we aimed to identify evidence that could indicate that capacity building was likely to be sustainable.</p> <p>Methods</p> <p>Four projects were selected as case studies using pre-determined criteria, including the achievement of sustainable capacity. By mapping the capacity building activities in each case study onto a framework previously used for evaluating health research capacity in Ghana, we were able to identify activities that were common to all projects. We used these activities to derive indicators which could be used in other projects to monitor progress towards building sustainable research capacity.</p> <p>Results</p> <p>Indicators of sustainable capacity building increased in complexity as projects matured and included</p> <p>- early engagement of stakeholders; explicit plans for scale up; strategies for influencing policies; quality assessments (<it>awareness and experiential stages)</it></p> <p>- improved resources; institutionalisation of activities; innovation <it>(expansion stage)</it></p> <p>- funding for core activities secured; management and decision-making led by southern partners <it>(consolidation stage)</it>.</p> <p>Projects became sustainable after a median of 66 months. The main challenges to achieving sustainability were high turnover of staff and stakeholders, and difficulties in embedding new activities into existing systems, securing funding and influencing policy development.</p> <p>Conclusions</p> <p>Our indicators of sustainable capacity building need to be tested prospectively in a variety of projects to assess their usefulness. For each project the evidence required to show that indicators have been achieved should evolve with the project and they should be determined prospectively in collaboration with stakeholders.</p

Modelling the spatial distribution of DEM Error

Assessment of a DEM’s quality is usually undertaken by deriving a measure of DEM accuracy – how close the DEM’s elevation values are to the true elevation. Measures such as Root Mean Squared Error and standard deviation of the error are frequently used. These measures summarise elevation errors in a DEM as a single value. A more detailed description of DEM accuracy would allow better understanding of DEM quality and the consequent uncertainty associated with using DEMs in analytical applications. The research presented addresses the limitations of using a single root mean squared error (RMSE) value to represent the uncertainty associated with a DEM by developing a new technique for creating a spatially distributed model of DEM quality – an accuracy surface. The technique is based on the hypothesis that the distribution and scale of elevation error within a DEM are at least partly related to morphometric characteristics of the terrain. The technique involves generating a set of terrain parameters to characterise terrain morphometry and developing regression models to define the relationship between DEM error and morphometric character. The regression models form the basis for creating standard deviation surfaces to represent DEM accuracy. The hypothesis is shown to be true and reliable accuracy surfaces are successfully created. These accuracy surfaces provide more detailed information about DEM accuracy than a single global estimate of RMSE

Evidence-informed health policy: are we beginning to get there at last

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Dielectric function of a two-component plasma including collisions

A multiple-moment approach to the dielectric function of a dense non-ideal plasma is treated beyond RPA including collisions in Born approximation. The results are compared with the perturbation expansion of the Kubo formula. Sum rules as well as Ward identities are considered. The relations to optical properties as well as to the dc electrical conductivity are pointed out.Comment: latex, 10 pages, 7 figures in ps forma

Towards building equitable health systems in Sub-Saharan Africa: lessons from case studies on operational research

<p>Abstract</p> <p>Background</p> <p>Published practical examples of how to bridge gaps between research, policy and practice in health systems research in Sub Saharan Africa are scarce. The aim of our study was to use a case study approach to analyse how and why different operational health research projects in Africa have contributed to health systems strengthening and promoted equity in health service provision.</p> <p>Methods</p> <p>Using case studies we have collated and analysed practical examples of operational research projects on health in Sub-Saharan Africa which demonstrate how the links between research, policy and action can be strengthened to build effective and pro-poor health systems. To ensure rigour, we selected the case studies using pre-defined criteria, mapped their characteristics systematically using a case study development framework, and analysed the research impact process of each case study using the RAPID framework for research-policy links. This process enabled analysis of common themes, successes and weaknesses.</p> <p>Results</p> <p>3 operational research projects met our case study criteria: HIV counselling and testing services in Kenya; provision of TB services in grocery stores in Malawi; and community diagnostics for anaemia, TB and malaria in Nigeria. <b>Political context and external influences: </b>in each case study context there was a need for new knowledge and approaches to meet policy requirements for equitable service delivery. Collaboration between researchers and key policy players began at the inception of operational research cycles. <b>Links</b>: critical in these operational research projects was the development of partnerships for capacity building to support new services or new players in service delivery. <b>Evidence: </b>evidence was used to promote policy dialogue around equity in different ways throughout the research cycle, such as in determining the topic area and in development of indicators.</p> <p>Conclusion</p> <p>Building equitable health systems means considering equity at different stages of the research cycle. Partnerships for capacity building promotes demand, delivery and uptake of research. Links with those who use and benefit from research, such as communities, service providers and policy makers, contribute to the timeliness and relevance of the research agenda and a receptive research-policy-practice interface. Our study highlights the need to advocate for a global research culture that values and funds these multiple levels of engagement.</p