2,031 research outputs found
PORTABLE MULTI-CAMERA SYSTEM: FROM FAST TUNNEL MAPPING TO SEMI-AUTOMATIC SPACE DECOMPOSITION AND CROSS-SECTION EXTRACTION
The paper outlines the first steps of a research project focused on the digitalization of underground tunnels for the mining industry. The aim is to solve the problem of rapidly, semi-automatically, efficiently, and reliably digitizing complex and meandering tunnels. A handheld multi-camera photogrammetric tool is used for the survey phase, which allows for the rapid acquisition of the image dataset needed to produce the 3D data. Moreover, since often, automatic, and fast acquisitions are not supported by easy-to-use tools to access and use the data at an operational level, a second aim of the research is to define a method able to arrange and organise the gathered data so that it would be easily accessible. The proposed approach is to compute the 3D skeleton of the surveyed environment by employing tools developed for the analysis of vascular networks in medical imagery. From the computed skeletonization of the underground tunnels, a method is proposed to automatically extrapolate valuable information such as cross-sections, decomposed portions of the tunnel, and the referenced images from the photogrammetric survey. The long-term research goal is to create an effective workflow, both at the hardware and software level, that can reduce computation times, process large amounts of data, and reduce dependency on high levels of experience
Individual Differences in Phonological Feedback Effects: Evidence for the Orthographic Recoding Hypothesis of Orthographic Learning
Share (1995) has proposed phonological recoding (the translation of letters into sounds) as a self-teaching mechanism through which readers establish complete lexical representations. More recently, McKague et al. (2008) proposed a similar role for orthographic recoding, i.e., feedback from sounds to letters, in building and refining lexical representations. We reasoned that an interaction between feedback consistency measures and spelling ability in a spelling decision experiment would lend support to this hypothesis. In a linear mixed effects logistic regression of accuracy data this interaction was significant. Better spellers but not poorer spellers were immune to feedback effects in deciding if a word is spelled correctly, which is consistent with McKague et al.’s prediction that the impact of phonological feedback on word recognition will diminish when the orthographic representation for an item is fully specified. The study demonstrates the importance of considering individual differences when investigating the role of phonology in reading
Lexical Stress and Linguistic Predictability Influence Proofreading Behavior
There is extensive evidence that the segmental (i.e., phonemic) layer of phonology is routinely activated during reading, but little is known about whether phonological activation extends beyond phonemes to subsegmental layers (which include articulatory information, such as voicing) and suprasegmental layers (which include prosodic information, such as lexical stress). In three proofreading experiments, we show that spelling errors are detected more reliably in syllables that are stressed than in syllables that are unstressed if comprehension is a goal of the reader, indicating that suprasegmental phonology is both active during silent reading and can influence orthographic processes. In Experiment 1, participants received instructions to read for both errors and comprehension, and we found that the effect of lexical stress interacted with linguistic predictability, such that detection of errors in more predictable words was aided by stress but detection of errors in less predictable words was not. This finding suggests that lexical stress patterns can be accessed prelexically if an upcoming word is sufficiently predictable from context. Participants with stronger vocabularies showed decreased effects of stress on task performance, which is consistent with previous findings that more skilled readers are less swayed by phonological information in decisions about orthographic form. In two subsequent experiments, participants were instructed to read only for errors (Experiment 2) or only for comprehension (Experiment 3); the effect of stress disappeared when participants read for errors and reappeared when participants read for comprehension, reconfirming our hypothesis that predictability is a driver of lexical stress effects. In all experiments, errors were detected more reliably in words that were difficult to predict from context than in words that were highly predictable. Taken together, this series of experiments contributes two important findings to the field of reading and cognition: (1) The prosodic property of lexical stress can influence orthographic processing, and (2) Predictability inhibits the detection of errors in written language processing.NICHD grant R01HD058566-02
Author fees paid for by the Northern Illinois University Libraries Open Access Publishing Fun
Universal reading processes are modulated by language and writing system
The connections among language, writing system, and reading are part of what confronts a child in learning to read. We examine these connections in addressing how reading processes adapt to the variety of written language and how writing adapts to language. The first adaptation (reading to writing), as evidenced in behavioral and neuroscience data, is achieved through a universal constraint that language places on writing and through the tuning of reading procedures imposed by specific features of writing systems. Children acquire skill in reading through increasing specialization of procedures tuned to their writing system, while also acquiring more general (universal) procedures that serve language mapping and cognitive control. For the second adaption (writing to language),
we present examples from several languages to suggest that writing systems tend to fit their linguistic properties, thus providing adaptive variation in writing-to-language mapping. We suggest that this writing-language fit facilitates the child’s learning how his or her writing system works
PROGETTAZIONE E REALIZZAZIONE DI UN COMPUTER-CLUSTER PER L’ANALISI DATI GPS CON I SOFTWARE GAMIT E QOCA
Negli ultimi 5 anni si è assistito ad un rapido aumento del numero di reti di stazioni GPS continue
(CGPS) attive sul territorio Italiano e, più in generale, nell’area Mediterranea. Se da un lato lo sviluppo delle
reti CGPS per lo studio dei fenomeni geofisici (terremoti, vulcani, variazioni del livello del mare, ecc...) è
ancora legato a particolari programmi di ricerca nei diversi paesi del bacino Mediterraneo, dall’altro un po’
in tutta Europa, ma anche in alcune aree del continente Africano, si è assistito alla nascita di reti CGPS
realizzate per scopi diversi da quelli geofisici (cartografici, topografici, catastali o per la navigazione). Se da
una parte le reti CGPS realizzate con criteri “geofisici” [es., Anzidei & Esposito, 2003] forniscono un dato
generalmente piĂą affidabile, in termini di stabilitĂ delle monumentazioni, qualitĂ del dati e continuitĂ
temporale delle osservazioni, dall’altra le reti CGPS regionali di tipo “non-geofisico”, nonostante una
distribuzione ovviamente disomogenea, hanno dimostrato di fornire comunque informazioni utili alla stima
dei campi di velocità e di deformazione crostale [es., D’Agostino et al., 2008], e di integrarsi il più delle
colte con altre reti di tipo “geofisico” esistenti. Al fine di migliorare la risoluzione spaziale del segnale
tettonico misurabile da una rete GPS, la scelta di realizzare un computer cluster per l’analisi dati GPS è stata
presa al fine di garantire un rapido, ed il piĂą possibile automatico, processamento di tutti i dati a disposizione
per l’area Euro-Mediterranea ed Africana.
I software comunemente utilizzati in ambito scientifico per l’analisi dei dati GPS sono il
GAMIT/GLOBK il BERNESE ed il GIPSY. Al di lĂ delle differenze legate agli algoritmi di calcolo dei tre
software in questione, e dei vantaggi o svantaggi di uno e dell’altro approccio di cui necessitano, una corretta
progettazione della dotazione hardware e software è il passaggio fondamentale per la creazione di un
moderno ed efficiente centro di analisi dati GPS finalizzato alla razionalizzazione delle risorse e dei costi.
Dato il numero molto elevato di stazioni CGPS oggi potenzialmente disponibili (diverse centinaia per
la sola area Mediterranea), una procedura che analizzi simultaneamente tutte le stazioni è difficilmente
praticabile. Nonostante recenti sviluppi di nuovi algoritmi [Blewitt, 2008] rendano effettivamente possibile
un’analisi simultanea di “mega-reti”, anche a scala globale, la disponibilità di calcolo su sistemi multi-
processore risulta comunque fondamentale. Nel caso specifico in cui il software utilizzato per l’analisi dei
dati si basi su soluzioni di rete (network solutions), come il BERNESE ed il GAMIT, riveste fondamentale
importanza lo sfruttamento ottimale delle risorse computazionali, e soprattutto la possibilitĂ di sfruttare
appieno le potenzialitĂ sia dei piĂą recenti computer multi-processore che dei nuovi processori ad architettura
multi-core. Nessuno dei software indicati precedentemente è implementato per il calcolo parallelo, di
conseguenza, lo sfruttamento delle architetture multi-processore o multi-core deve passare necessariamente
per altre vie. Una di queste è quella del calcolo distribuito (distributed-processing), in cui, ad esempio,
diversi nodi di calcolo (che possono essere diverse macchine, diversi processori, o diversi core di processori)
analizzano reti CGPS diverse, o diversi giorni della stessa rete CGPS. Se da una parte il mercato offre
numerose soluzioni commerciali per la realizzazione di procedure di calcolo distribuito (Microsoft Windows
Compute Cluster Server 2003, Sun Cluster, NEC ExpressCluster; IBM Parallel Sysplex, per citarne alcuni),
dall’altra la disponibilità di software open source per questo tipo di scopi è oggi completa e ben integrata nei
sistemi operativi UNIX based. Â
In questo rapporto tecnico viene descritta la procedura seguita per la realizzazione di un nuovo server
per l’analisi dei dati GPS presso la Sede INGV di Bologna basato su un computer cluster, utilizzando
software Open Source, in ambiente GNU/Linux
SKELETAL MUSCLE AND CIRCULATING MICRORNAS IN MYOTONIC DISTROPHY TYPE 1
In Myotonic Dystrophy type 1 (DM1), the accumulation of transcripts containing CUG triplet expansions leads to the dysregulation of multiple cellular processes, including RNA splicing and microRNA (miRNAs) synthesis. This project aims to find functional miRNAs that are specifically deregulated in muscles of DM1 patients, and to identify circulating miRNAs in the plasma of DM1 patients that could be used as biomarkers of DM1 disease progression. Preliminary studies had previously identified a group of miRNAs that were deregulated in the plasma or serum of small groups of DM1 patients. In this work, very stringent selection and normalization criteria were adopted to validate or disprove these miRNAs in 103 DM1 patients and 111 matched controls. We found that 8 miRNAs out of 12 were significantly deregulated in DM1 patients and that the levels of these miRNAs discriminated DM1 from controls significantly. Next, we determined a \u201cDM1-miRNAs score\u201d, calculated averaging the values of all 8 miRNAs, and a \u201cmiR-133a/b score\u201d obtained averaging the levels of the two miR-133 members, both displaying a good ability to discriminate between DM1 and control subjects. Additionally, both scores correlated with muscle strength and Creatine Kinase levels. Moreover, 7 out of 8 miRNAs were found deregulated also in 30 patient affected by Myotonic Dystrophy type 2. The second aim of this work was the identification of miRNA/target mRNAs couples deregulated in skeletal muscles of DM1 patients. To this aim, the RNAs associated to RISC effector complex were analyzed from muscle biopsies of DM1 patients and healthy individuals and RNA-Sequencing was used to identify RISC-associated small RNAs (miRNAs) and long RNAs (mRNAs). A number of small and long RNAs differentially expressed in RISC complexes of DM1 vs healthy controls were identified, that showed statistically significant modulation. Next, using target prediction algorithms, miRNA-mRNA couples deregulated in DM1 were identified. RNA-sequencing data confirmed in independent qPCR assays, analyzing larger groups of DM1 patients and controls. Moreover, using myogenic cell models derived from dermal fibroblasts of DM1 patients and healthy individuals, a subset of these interactions was confirmed, validating this in vitro system for future functional studies.
In conclusion, this study identified relevant tissue miRNAs aberrantly expressed in DM1 and validated plasma miRNAs as potential DM1 biomarkers
V-SLAM-AIDED PHOTOGRAMMETRY TO PROCESS FISHEYE MULTI-CAMERA SYSTEMS SEQUENCES
The advent of mobile mapping systems (MMSs) and computer vision algorithms has enriched a wide range of navigation and mapping tasks such as localisation, 3D motion estimation and 3D mapping. This study focuses on Visual Simultaneous Localisation and Mapping (V-SLAM) in the context of two in-houses MMSs: Ant3D, a patented five-fisheye multi-camera rig and GeoRizon, a high-resolution stereo fisheye rig. The aim is to leverage V-SLAM to enhance the systems performance in near-real-time and non-real-time 3D reconstruction applications. The research investigates both Monocular and Stereo V-SLAM applied to both MMSs and tackles the challenge of combining the V-SLAM estimated trajectory of one or a pair of cameras with known multi-camera relative orientation. We propose a state-of-the-art code that serves as a flexible and extensible platform for MMSs image acquisition and processing, along with an adapted version of the well-established ORB-SLAM3.0. Evaluation is performed in a cultural heritage challenging setup: the Minguzzi spiral staircase in the Duomo di Milano Cathedral. Performed tests highlight that introducing V-SLAM trajectories as well as pre-calibrated interior orientation and multi-camera constraints improve speed, applicability and accuracy of 3D surveys
Quasiparticles dynamics in high-temperature superconductors far from equilibrium: an indication of pairing amplitude without phase coherence
We perform time resolved photoelectron spectroscopy measurements of optimally
doped \tn{Bi}_2\tn{Sr}_2\tn{CaCu}_2\tn{O}_{8+\delta} (Bi-2212) and
\tn{Bi}_2\tn{Sr}_{2-x}\tn{La}_{x}\tn{Cu}\tn{O}_{6+\delta} (Bi-2201). The
electrons dynamics show that inelastic scattering by nodal quasiparticles
decreases when the temperature is lowered below the critical value of the
superconducting phase transition. This drop of electronic dissipation is
astonishingly robust and survives to photoexcitation densities much larger than
the value sustained by long-range superconductivity. The unconventional
behaviour of quasiparticle scattering is ascribed to superconducting
correlations extending on a length scale comparable to the inelastic path. Our
measurements indicate that strongly driven superconductors enter in a regime
without phase coherence but finite pairing amplitude. The latter vanishes near
to the critical temperature and has no evident link with the pseudogap observed
by Angle Resolved Photoelectron Spectroscopy (ARPES).Comment: 7 pages, 5 Figure
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