Efficient contour-based shape representation and matching

This paper presents an efficient method for calculating the similarity between 2D closed shape contours. The proposed algorithm is invariant to translation, scale change and rotation. It can be used for database retrieval or for detecting regions with a particular shape in video sequences. The proposed algorithm is suitable for real-time applications. In the first stage of the algorithm, an ordered sequence of contour points approximating the shapes is extracted from the input binary images. The contours are translation and scale-size normalized, and small sets of the most likely starting points for both shapes are extracted. In the second stage, the starting points from both shapes are assigned into pairs and rotation alignment is performed. The dissimilarity measure is based on the geometrical distances between corresponding contour points. A fast sub-optimal method for solving the correspondence problem between contour points from two shapes is proposed. The dissimilarity measure is calculated for each pair of starting points. The lowest dissimilarity is taken as the final dissimilarity measure between two shapes. Three different experiments are carried out using the proposed approach: letter recognition using a web camera, our own simulation of Part B of the MPEG-7 core experiment “CE-Shape1” and detection of characters in cartoon video sequences. Results indicate that the proposed dissimilarity measure is aligned with human intuition

Representations of first order function types as terminal coalgebras

Cosmic rays provide an important source for free electrons in Earth's atmosphere and also in dense interstellar regions where they produce a prevailing background ionization. We utilize a Monte Carlo cosmic ray transport model for particle energies of 10(6) eV <E <10(9) eV, and an analytic cosmic ray transport model for particle energies of 10(9) eV <E <10(12) eV in order to investigate the cosmic ray enhancement of free electrons in substellar atmospheres of free-floating objects. The cosmic ray calculations are applied to Drift-Phoenix model atmospheres of an example brown dwarf with effective temperature T-eff = 1500 K, and two example giant gas planets (T-eff = 1000 K, 1500 K). For the model brown dwarf atmosphere, the electron fraction is enhanced significantly by cosmic rays when the pressure p(gas) <10(-2) bar. Our example giant gas planet atmosphere suggests that the cosmic ray enhancement extends to 10(-4)-10(-2) bar, depending on the effective temperature. For the model atmosphere of the example giant gas planet considered here (T-eff = 1000 K), cosmic rays bring the degree of ionization to f(e) greater than or similar to 10(-8) when p(gas) <10(-8) bar, suggesting that this part of the atmosphere may behave as a weakly ionized plasma. Although cosmic rays enhance the degree of ionization by over three orders of magnitude in the upper atmosphere, the effect is not likely to be significant enough for sustained coupling of the magnetic field to the gas.Publisher PDFPeer reviewe

The large-scale general-relativistic correction for Newtonian mocks

We clarify the subtle issue of finding the correct mapping of Newtonian simulations to light-cone observables at very large distance scales. A faithful general-relativistic interpretation specifies a gauge, i.e. a chart that relates the simulation data to points of the space-time manifold. It has already been pointed out that the implicit gauge choice of Newtonian simulations is indeed different from the Poisson gauge that is commonly adopted for relativistic calculations, the difference being most significant at large scales. It is therefore inconsistent, for example, to predict weak-lensing observables from simulations unless this gauge issue is properly accounted for. Using perturbation theory as well as fully relativistic N-body simulations we quantify the systematic error introduced this way, and we discuss several solutions that would render the calculations relativistically self-consistent.Comment: 10 pages, 5 figures; v2: minor revision with additional content, matches accepted manuscrip

Using dempster-shafer theory to fuse multiple information sources in region-based segmentation

This paper presents a new method for segmentation of images into large regions that reflect the real world objects present in a scene. It explores the feasibility of utilizing spatial configuration of regions and their geometric properties (the so-called Syntactic Visual Features [1]) for improving the correspondence of segmentation results produced by the well-known Recursive Shortest Spanning Tree (RSST) algorithm [2] to semantic objects present in the scene. The main contribution of this paper is a novel framework for integration of evidence from multiple sources with the region merging process based on the Dempster-Shafer (DS) theory [3] that allows integration of sources providing evidence with different accuracy and reliability. Extensive experiments indicate that the proposed solution limits formation of regions spanning more than one semantic object

Interactive object contour extraction for shape modeling

In this paper we present a semi-automatic segmentation approach suitable for extracting object contours as a precursor to 2D shape modeling. The approach is a modified and extended version of an existing state-of-the-art approach based on the concept of a Binary Partition Tree (BPT) [1]. The resulting segmentation tool facilitates quick and easy extraction of an object’s contour via a small amount of user interaction that is easy to perform, even in complicated scenes. Illustrative segmentation results are presented and the usefulness of the approach in generating object shape models is discussed

Senior Recital, Robert Williamson III, trumpet

Senior RecitalRobert Williamson III, trumpetMagdalena Adamek, pianoMonday, December 9, 2019 at 6pmSonia Vlahcevic Concert HallSingleton Center for the Performing Arts922 Park AvenueRichmond, VirginiaThe presentation of this senior recital will fulfill in part the requirements for the Bachelor of Music degree in Performance. Robert Williamson studies trumpet with Rex Richardson and Brian Strawley

Lifting the veil of accounting information under different accounting standards: lessons learned from the German experiment

It is well-known from US-related studies that investors systematically overreact to accrual-based accounting information. We address the question to what extent this accrual anomaly is related to different accounting standards. We provide empirical evidence that the accrual anomaly is also present in Germany. However, this anomaly has become particularly important after the year 2000 and cannot be detected for firms presenting their financial statements under German GAAP. It is argued that introducing true and fair view accounting, like IFRS, that relies on difficult-to-verify information, may not be suitable to improve accounting information quality in the context of a weak corporate governance system. --accrual anomaly,earnings persistency,conservative accounting,true and fair view accounting,accounting standards,accounting regulation,empirical accounting research,German GAAP,IFRS/IAS,US-GAAP