3,427 research outputs found
Binary Adaptive Semi-Global Matching Based on Image Edges
Image-based modeling and rendering is currently one of the most challenging topics in Computer Vision and Photogrammetry. The key issue here is building a set of dense correspondence points between two images, namely dense matching or stereo matching. Among all dense matching algorithms, Semi-Global Matching (SGM) is arguably one of the most promising algorithms for real-time stereo vision. Compared with global matching algorithms, SGM aggregates matching cost from several (eight or sixteen) directions rather than only the epipolar line using Dynamic Programming (DP). Thus, SGM eliminates the classical “streaking problem” and greatly improves its accuracy and efficiency. In this paper, we aim at further improvement of SGM accuracy without increasing the computational cost. We propose setting the penalty parameters adaptively according to image edges extracted by edge detectors. We have carried out experiments on the standard Middlebury stereo dataset and evaluated the performance of our modified method with the ground truth. The results have shown a noticeable accuracy improvement compared with the results using fixed penalty parameters while the runtime computational cost was not increased
K-5 Educators\u27 Perceptions of the Role of Speech Language Pathologists
Rarely is a school-based speech language pathologist (SLP) thought of as an active contributor to the achievement of students or to the learning community in general. Researchers have found benefits for students when members of the learning community collaborate, and the SLP should be a part of this community collaboration. This qualitative case study examined elementary school teachers\u27, administrators\u27, and reading specialists\u27 perspectives related to knowledge of and the inclusion of the SLP in the learning community at a local elementary school in central Georgia. Schon\u27s theory of reflective practice and Coleman\u27s theory of social capital provided the conceptual framework. Via an open-ended questionnaire and intensive interviews, 8 educators with 3 or more years of experience in 1 of the K-5 elementary schools in this local community provided data for this study. Data were recorded, transcribed, and analyzed through inductive methods using open and axial coding with thematic analysis. The results of the study showed 4 common themes that the participants felt were important. These themes included the fact that teachers understood the SLP to be a resource, but were unsure how to access their specialty; teachers and SLPs needed allotted time to work together; teachers and SLPs needed to communicate frequently; and teachers desired more knowledge of the SLP\u27s role in the educational setting. Important implications for social change in elementary school learning communities include increasing involvement of the SLP, promoting SLP involvement in the identification of at-risk students, increasing educator awareness of the SLP\u27s benefit, and increasing collaboration between SLPs and educators promoted through a 3-day professional learning project
More Torsion in the Homology of the Matching Complex
A matching on a set is a collection of pairwise disjoint subsets of
of size two. Using computers, we analyze the integral homology of the matching
complex , which is the simplicial complex of matchings on the set . The main result is the detection of elements of order in the
homology for . Specifically, we show that there are
elements of order 5 in the homology of for and for . The only previously known value was , and in this particular
case we have a new computer-free proof. Moreover, we show that there are
elements of order 7 in the homology of for all odd between 23 and 41
and for . In addition, there are elements of order 11 in the homology of
and elements of order 13 in the homology of . Finally, we
compute the ranks of the Sylow 3- and 5-subgroups of the torsion part of
for ; a complete description of the homology
already exists for . To prove the results, we use a
representation-theoretic approach, examining subcomplexes of the chain complex
of obtained by letting certain groups act on the chain complex.Comment: 35 pages, 10 figure
A planning program and the design for a single enterprise community in the Subarctic
Thesis (M.C.P.) Massachusetts Institute of Technology. Dept. of Architecture, 1956.ACCOMPANYING drawings held by MIT Museum.Includes bibliographies.by James Arthur Hatcher and David Dunsmore Wallace.M.C.P
Schrijver graphs and projective quadrangulations
In a recent paper [J. Combin. Theory Ser. B}, 113 (2015), pp. 1-17], the
authors have extended the concept of quadrangulation of a surface to higher
dimension, and showed that every quadrangulation of the -dimensional
projective space is at least -chromatic, unless it is bipartite.
They conjectured that for any integers and , the
Schrijver graph contains a spanning subgraph which is a
quadrangulation of . The purpose of this paper is to prove the
conjecture
Dualities in persistent (co)homology
We consider sequences of absolute and relative homology and cohomology groups
that arise naturally for a filtered cell complex. We establish algebraic
relationships between their persistence modules, and show that they contain
equivalent information. We explain how one can use the existing algorithm for
persistent homology to process any of the four modules, and relate it to a
recently introduced persistent cohomology algorithm. We present experimental
evidence for the practical efficiency of the latter algorithm.Comment: 16 pages, 3 figures, submitted to the Inverse Problems special issue
on Topological Data Analysi
On the Expansions in Spin Foam Cosmology
We discuss the expansions used in spin foam cosmology. We point out that
already at the one vertex level arbitrarily complicated amplitudes contribute,
and discuss the geometric asymptotics of the five simplest ones. We discuss
what type of consistency conditions would be required to control the expansion.
We show that the factorisation of the amplitude originally considered is best
interpreted in topological terms. We then consider the next higher term in the
graph expansion. We demonstrate the tension between the truncation to small
graphs and going to the homogeneous sector, and conclude that it is necessary
to truncate the dynamics as well.Comment: 17 pages, 4 figures, published versio
Quantum statistics on graphs
Quantum graphs are commonly used as models of complex quantum systems, for
example molecules, networks of wires, and states of condensed matter. We
consider quantum statistics for indistinguishable spinless particles on a
graph, concentrating on the simplest case of abelian statistics for two
particles. In spite of the fact that graphs are locally one-dimensional, anyon
statistics emerge in a generalized form. A given graph may support a family of
independent anyon phases associated with topologically inequivalent exchange
processes. In addition, for sufficiently complex graphs, there appear new
discrete-valued phases. Our analysis is simplified by considering combinatorial
rather than metric graphs -- equivalently, a many-particle tight-binding model.
The results demonstrate that graphs provide an arena in which to study new
manifestations of quantum statistics. Possible applications include topological
quantum computing, topological insulators, the fractional quantum Hall effect,
superconductivity and molecular physics.Comment: 21 pages, 6 figure
On globally non-trivial almost-commutative manifolds
Within the framework of Connes' noncommutative geometry, we define and study
globally non-trivial (or topologically non-trivial) almost-commutative
manifolds. In particular, we focus on those almost-commutative manifolds that
lead to a description of a (classical) gauge theory on the underlying base
manifold. Such an almost-commutative manifold is described in terms of a
'principal module', which we build from a principal fibre bundle and a finite
spectral triple. We also define the purely algebraic notion of 'gauge modules',
and show that this yields a proper subclass of the principal modules. We
describe how a principal module leads to the description of a gauge theory, and
we provide two basic yet illustrative examples.Comment: 34 pages, minor revision
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