Search results for "DFA"
showing 10 items of 54 documents
Effects of different boundary conditions and palaeotopographies on the onshore response of tsunamis in a numerical model – A case study from western …
2016
Abstract Hydrodynamic numerical models are essential in modern tsunami hazard assessment. They allow the economical simulation of possible tsunami scenarios for areas at risk and provide reliable and detailed insights into local onshore dynamics. This is especially true when simulations are calibrated with field traces of past tsunami inundation events. Following this approach, the current study focuses on palaeotsunami events indicated by sedimentary and geomorphological field traces in the northern Gulf of Kyparissia (NW Greece). Based on three different digital elevation models (DEM) – reflecting the recent and two palaeotopographies – various tsunami wave constellations according to the…
Sexing birds using discriminant function analysis: a critical appraisal.
2011
9 pages; International audience; Discriminant function analysis (DFA) based on morphological measurements is a quick, inexpensive, and efficient method for sex determination in field studies on cryptically monomorphic bird species. However, behind the apparent standardization and relative simplicity of DFA lie subtle differences and pitfalls that have been neglected in some studies. Most of these concerns directly affect assessment of the discriminant performance, a parameter of crucial importance in practice because it provides a measure of the quality of an equation that may be used in later field studies. Using results from 141 published studies and simulations based on a large data set …
Morphology, performance and attachment function in Corynosoma spp. (Acanthocephala)
2018
Background: Functional inference on the attachment of acanthocephalans has generally been drawn directly from morphology. However, performance of structures is often non-intuitive and context-dependent, thus performance analysis should be included whenever possible to improve functional interpretation. In acanthocephalans, performance analysis of attachment is available only for Acanthocephalus ranae, a species that solely relies on the proboscis to attach. Here we compare body morphology and muscle arrangement in 13 species of Corynosoma, which use their spiny body as a fundamental holdfast. A basic performance analysis using live cystacanths of two representative species is also provided.…
Orbital volume and shape in Treacher Collins syndrome
2018
Orbito-palpebral reconstruction is a challenge in Treacher Collins syndrome (TCS). This study investigates orbital phenotypes in TCS using cephalometry and orbital shape analysis. Eighteen TCS and 52 control patients were included in this study, using the Dr Warehouse database. Orbital cephalometry was based on 20 landmarks, 10 planes, 16 angles, and 22 distances. Orbits were segmented. Registration-based, age-specific mean models were generated using semi-automatic segmentation, and aligned and compared using color-coded distance maps - mean absolute distance (MAD), Hausdorff distance (HD), and Dice similarity coefficient (DSC). Symmetry was assessed by mirroring and DSC computing. Central…
BIODIVERSITA’ DELLE COMUNITA’ BATTERICHE IN UN SUOLO SOTTOPOSTO A BIORISANAMENTO IN MICROCOSMO
2021
Gli idrocarburi (HC) sono uno dei principali inquinanti ambientali. Una tecnologia promettente per il trattamento di siti contaminati si basa sulla biodegradazione degli inquinanti da parte di popolazioni microbiche capaci di utilizzare HC come fonte di carbonio ed energia (Biorisanamento). La necessità di risanare siti contaminati richiede da una parte la caratterizzazione delle comunità microbiche coinvolte nella biodegradazione, dall’altra lo sviluppo di interventi volti a migliorare il potenziale metabolico dei microrganismi degradatori. La nostra attività di ricerca ha avuto come obiettivo quello di caratterizzare e analizzare la biodiversità di comunità microbiche di un suolo contamin…
Hamming, Permutations and Automata
2007
Quantum finite automata with mixed states are proved to be super-exponentially more concise rather than quantum finite automata with pure states. It was proved earlier by A.Ambainis and R.Freivalds that quantum finite automata with pure states can have exponentially smaller number of states than deterministic finite automata recognizing the same language. There was a never published "folk theorem" proving that quantum finite automata with mixed states are no more than superexponentially more concise than deterministic finite automata. It was not known whether the super-exponential advantage of quantum automata is really achievable. We prove that there is an infinite sequence of distinct int…
Super-Exponential Size Advantage of Quantum Finite Automata with Mixed States
2008
Quantum finite automata with mixed states are proved to be super-exponentially more concise rather than quantum finite automata with pure states. It was proved earlier by A.Ambainis and R.Freivalds that quantum finite automata with pure states can have exponentially smaller number of states than deterministic finite automata recognizing the same language. There was a never published "folk theorem" proving that quantum finite automata with mixed states are no more than super-exponentially more concise than deterministic finite automata. It was not known whether the super-exponential advantage of quantum automata is really achievable. We use a novel proof technique based on Kolmogorov complex…
Delivering Freight, ASAP! Una applicazione mobile per l'apprendimento dei concetti di base sugli Automi a Stati Finiti
2015
Finite State Automata (FA) are a family of automata quite popular in the context of computational intelligence, as they allow representation of complex information and behaviour via graphs that are easy to design and execute. Every Theoretical Computer Science curriculum, be it administered to pure computer scientists or engineers alike, has a module on FAs that teaches how to design, build and run them, on top of some important theorems highlighting fundamental results. Despite that, students often find difficult to absorb FAs properly, and often they resort to learn their basic usage and example by memory. Delivering Freight ASAP! is a mobile game with a mission: promote the correct learn…
Hidden Markov random field model and Broyden–Fletcher–Goldfarb–Shanno algorithm for brain image segmentation
2018
International audience; Many routine medical examinations produce images of patients suffering from various pathologies. With the huge number of medical images, the manual analysis and interpretation became a tedious task. Thus, automatic image segmentation became essential for diagnosis assistance. Segmentation consists in dividing the image into homogeneous and significant regions. We focus on hidden Markov random fields referred to as HMRF to model the problem of segmentation. This modelisation leads to a classical function minimisation problem. Broyden-Fletcher-Goldfarb-Shanno algorithm referred to as BFGS is one of the most powerful methods to solve unconstrained optimisation problem. …
Epichristoffel Words and Minimization of Moore Automata
2014
This paper is focused on the connection between the combinatorics of words and minimization of automata. The three main ingredients are the epichristoffel words, Moore automata and a variant of Hopcroft's algorithm for their minimization. Epichristoffel words defined in [14] generalize some properties of circular sturmian words. Here we prove a factorization property and the existence of the reduction tree, that uniquely identifies the structure of the word. Furthermore, in the paper we investigate the problem of the minimization of Moore automata by defining a variant of Hopcroft's minimization algorithm. The use of this variant makes simpler the computation of the running time and consequ…