Shape-from-shading using the heat equation

This paper offers two new directions to shape-from-shading, namely the use of the heat equation to smooth the field of surface normals and the recovery of surface height using a low-dimensional embedding. Turning our attention to the first of these contributions, we pose the problem of surface normal recovery as that of solving the steady state heat equation subject to the hard constraint that Lambert's law is satisfied. We perform our analysis on a plane perpendicular to the light source direction, where the z component of the surface normal is equal to the normalized image brightness. The x - y or azimuthal component of the surface normal is found by computing the gradient of a scalar field that evolves with time subject to the heat equation. We solve the heat equation for the scalar potential and, hence, recover the azimuthal component of the surface normal from the average image brightness, making use of a simple finite difference method. The second contribution is to pose the problem of recovering the surface height function as that of embedding the field of surface normals on a manifold so as to preserve the pattern of surface height differences and the lattice footprint of the surface normals. We experiment with the resulting method on a variety of real-world image data, where it produces qualitatively good reconstructed surfaces

Graph edit distance from spectral seriation

This paper is concerned with computing graph edit distance. One of the criticisms that can be leveled at existing methods for computing graph edit distance is that they lack some of the formality and rigor of the computation of string edit distance. Hence, our aim is to convert graphs to string sequences so that string matching techniques can be used. To do this, we use a graph spectral seriation method to convert the adjacency matrix into a string or sequence order. We show how the serial ordering can be established using the leading eigenvector of the graph adjacency matrix. We pose the problem of graph-matching as a maximum a posteriori probability (MAP) alignment of the seriation sequences for pairs of graphs. This treatment leads to an expression in which the edit cost is the negative logarithm of the a posteriori sequence alignment probability. We compute the edit distance by finding the sequence of string edit operations which minimizes the cost of the path traversing the edit lattice. The edit costs are determined by the components of the leading eigenvectors of the adjacency matrix and by the edge densities of the graphs being matched. We demonstrate the utility of the edit distance on a number of graph clustering problems

A graph-spectral approach to shape-from-shading

In this paper, we explore how graph-spectral methods can be used to develop a new shape-from-shading algorithm. We characterize the field of surface normals using a weight matrix whose elements are computed from the sectional curvature between different image locations and penalize large changes in surface normal direction. Modeling the blocks of the weight matrix as distinct surface patches, we use a graph seriation method to find a surface integration path that maximizes the sum of curvature-dependent weights and that can be used for the purposes of height reconstruction. To smooth the reconstructed surface, we fit quadrics to the height data for each patch. The smoothed surface normal directions are updated ensuring compliance with Lambert's law. The processes of height recovery and surface normal adjustment are interleaved and iterated until a stable surface is obtained. We provide results on synthetic and real-world imagery

Alberta School Principals’ Use of Professional Portfolios in Teacher Hiring

Creating a professional portfolio is a requirement for most pre-service teachers in Alberta. Little is known, however, about principals’ use of applicant portfolios in hiring. In response, researchers conducted an online survey of principals throughout the province. Findings indicate a preference for traditional job application items (e.g., a resumé, reference letters, and letter of introduction) and teacher competence indicators (e.g., teacher mentor and school administrator assessments, student assessment methods, and a classroom management plan). Examining attitudes and hiring practices provides direction for creating portfolios that attend to the actual needs and interests of principals in the province, thereby enhancing the employment prospects of new teachers.La création d’un portefeuille professionnel est une exigence pour la plupart des enseignants étudiants en Alberta. On sait peu, toutefois, à propos de l’utilisation des portefeuilles de candidats par les directeurs dans le processus d’embauche. En réponse, les chercheurs ont mené une enquête en ligne auprès des directeurs d’écoles de l’ensemble de la province. Les résultats indiquent une préférence pour les éléments traditionnels d’une demande d’emploi (p. ex., un curriculum vitae, des lettres de références, et une lettre d’introduction) et les indicateurs de compétence des enseignants (p. ex., les évaluations du mentor d’enseignant et de l’administrateur scolaire, les méthodes d’évaluation des élèves, et un plan de gestion de classe). L’examen des attitudes et pratiques d’embauche fournit une orientation pour créer des portfeuilles qui répondent aux besoins et aux intérêts réels des directeurs d’école dans la province, améliorant ainsi les perspectives d’emploi des nouveaux enseignants

Response to Corner Brook Pulp & Paper Tire Derived Fuel (TDF) Co-Firing Trial Project Proponent: Corner Brook Pulp & Paper Ltd. (Reg. 1539)

While acknowledging potential economic benefits for Corner Brook Pulp and Paper (CBPP) in using tire-derived fuel (TDF), we remain unconvinced of the net public and environmental health benefits of its use and are concerned with the methodology of the proposed test. We hope that this overview of our concerns can help the Department of Environment and Conservation (DEC) make an informed decision regarding the testing of TDF at CBPP. Guiding our submission is the precautionary principle, which has been adopted by all relevant parties, including the Government of Canada, the Government of Newfoundland and Labrador and CBPP. As such and in light of the issues below, it is our position that additional research is required before moving to a test trial. This can be achieved either by conducting a full Environmental Impact Statement, including component studies and additional public hearings, or by rejecting the undertaking outright

Feedback of patient-reported outcomes to healthcare professionals for comparing health service performance: a scoping review

Objective: Patient-reported outcomes (PROs) provide self-reported patient assessments of their quality of life, daily functioning, and symptom severity after experiencing an illness and having contact with the health system. Feeding back summarised PROs data, aggregated at the health-service level, to healthcare professionals may inform clinical practice and quality improvement efforts. However, little is known about the best methods for providing these summarised data in a way that is meaningful for this audience. Therefore, the aim of this scoping review was to summarise the emerging approaches to PROs data for &lsquo;service-level&rsquo; feedback to healthcare professionals. Setting: Healthcare professionals receiving PROs data feedback at the health-service level. Data sources: Databases selected for the search were Embase, Ovid Medline, Scopus, Web of Science and targeted web searching. The main search terms included: &lsquo;patient-reported outcome measures&rsquo;, &lsquo;patient-reported outcomes&rsquo;, &lsquo;patient-centred care&rsquo;, &lsquo;value-based care&rsquo;, &lsquo;quality improvement&rsquo; and &lsquo;feedback&rsquo;. Studies included were those that were published in English between January 2009 and June 2019. Primary and secondary outcome measures: Data were extracted on the feedback methods of PROs to patients or healthcare providers. A standardised template was used to extract information from included documents and academic publications. Risk of bias was assessed using Joanna Briggs Institute Levels of Evidence for Effectiveness. Results: Overall, 3480 articles were identified after de-duplication. Of these, 19 academic publications and 22 documents from the grey literature were included in the final review. Guiding principles for data display methods and graphical formats were identified. Seven major factors that may influence PRO data interpretation and use by healthcare professionals were also identified. Conclusion: While a single best format or approach to feedback PROs data to healthcare professionals was not identified, numerous guiding principles emerged to inform the field.</jats:sec