Search results for "Concept-based"
showing 3 items of 3 documents
Teaching and Learning School Informatics: A Concept-Based Pedagogical Approach
2009
While informatics is a well-established discipline in higher education around the world, it is not the case in secondary education, with the exception of a few countries. Generally, what is taught is not informatics as a subject with its own methods, concepts, and principles, but some software tools with the goal that the use is sufficient for students to acquire skills. In addition, an analysis of the current situation reveals that the real competencies of teachers and students in informatics are far weaker than might be expected in secondary education. This work proposes a concept-based pedagogical approach to school informatics. The aim is to provide the students with a more thorough und…
AX-PET: Concept, proof of principle and first results with phantoms
2010
AX-PET is a novel PET concept based on long crystals axially arranged and orthogonal Wavelength shifter (WLS) strips, both individually readout by Geiger-mode Avalanche Photo Diodes (G-APD). Its design was conceived in order to reduce the parallax error and simultaneously improve spatial resolution and sensitivity. The assessment of the AX-PET concept and potential was carried out through a set of measurements comprising individual module characterizations and scans in coincidence mode of point-like and extended sources. The estimated energy and spatial resolutions from point-like measurements are R FWHM =11.6% (at 511 keV) and 1.7–1.9 mm (FWHM) respectively as measured with point-like sour…
Learning to Rank Images for Complex Queries in Concept-based Search
2018
Concept-based image search is an emerging search paradigm that utilizes a set of concepts as intermediate semantic descriptors of images to bridge the semantic gap. Typically, a user query is rather complex and cannot be well described using a single concept. However, it is less effective to tackle such complex queries by simply aggregating the individual search results for the constituent concepts. In this paper, we propose to introduce the learning to rank techniques to concept-based image search for complex queries. With freely available social tagged images, we first build concept detectors by jointly leveraging the heterogeneous visual features. Then, to formulate the image relevance, …