Search results for "Dispersion"
showing 10 items of 1101 documents
Measurement of the soliton number in guiding media through continuum generation.
2020
No general approach is available yet to measure directly the ratio between chromatic dispersion and the nonlinear coefficient, and hence the soliton number for a given optical pulse, in an arbitrary guiding medium. Here we solve this problem using continuum generation. We experimentally demonstrate our method in polarization-maintaining and single-mode fibers with positive and negative chromatic dispersion. Our technique also offers new opportunities to determine the chromatic dispersion of guiding media over a broad spectral range while pumping at a fixed wavelength. (C) 2020 Optical Society of America
Simultaneous polarization attraction and Raman amplification of a light beam in optical fibers
2012
International audience; In this paper, we demonstrate that it is possible to combine both Raman amplification and polarization attraction of a signal wave in a single optical fiber by means of a counterpropagating scheme. Experiments were performed near 1550 nm in a continuous wave regime and by means of a 10 Gbit ∕ s return-to-zero signal injected in a 20 kmlong low polarization mode dispersion optical fiber. Complete repolarization and 6.7 dB amplification of the signal wave was achieved by injecting a 850 mW, 1480 nm counterpropagating polarized pump wave.
Estimating the safety performance function for urban unsignalized four-legged one-way intersections in Palermo, Italy
2014
Abstract Starting from consideration that urban intersections are sites with promise for safety and operational improvements, the paper describes the steps taken to develop a crash predictive model for estimating the safety performance of urban unsignalized intersections located in Palermo, Italy. The focus is on unsignalized four-legged one-way intersections widespread in Italian downtowns. The sample considered in the study consist of 92 intersections in Palermo, Italy. For the study were collected crashes occurred in the sites during the years 2006-2012, geometric design and functional characteristics and traffic flow. Results showed that data were overdispersed and NB1 distributed. In o…
Tra reale e virtuale: problematiche pedagogiche. Seminari e conversazioni
2009
Consumers' privacy, selling of information, and security in digital markets
2019
La era digital se caracteriza por la gran producción de datos (algunos de ellos de naturaleza privada) a gran escala. La vulnerabilidad y la exposición está ocurriendo a un ritmo sin precedentes, produciendo grandes incentivos económicos para los propietarios de estos datos. Sin embargo, los proveedores de dichos datos, que a menudo son consumidores de contenido gratuito en plataformas digitales, están comenzando a desarrollar problemas de privacidad y, por lo tanto, conducen a la consiguiente reducción de la confianza en los mercados digitales. El objetivo principal de esta tesis es analizar la privacidad desde una perspectiva informativa y fuente de ineficiencias en el mercado. Además, la…
Diffusione del punteruolo rosso delle palme a Palermo a tre anni dalla sua introduzione.
2009
L’orientamento nel primo biennio di un istituto professionale
2017
L’intervento mirava a verificare se, integrando l’azione della scuola, che è un’agenzia educativa formale, con quella di agenzie formative non formali che operano nello stesso territorio dell’Istituto professionale coinvolto nella ricerca, si abbassava il tasso di dispersione scolastica nel primo biennio. Al termine delle nuove iniziative educative realizzate, dal confronto con i risultati degli anni precedenti, si è notato un aumento dei voti in matematica e in lingua italiana, una diminuzione delle assenze e dei ritardi all’ingresso e un aumento dei contatti tra genitori e insegnanti. The intervention was aimed to verify whether the integration of school action (being school a formal educ…
Autosabotaggio e procrastinazione: strategie di prevenzione del sentire mafioso
2017
Nell’analisi della dispersione scolastica il fenomeno della procrastination è stato spesso sottovalutato. La nostra ricerca ha correlato i processi di selfhandicapping con quelli connessi all’abbandono del percorso di studio. La procrastination è stata studiata come processo di co-stante rinvio degli impegni scolastici e delle occasioni di recupero. Lo studio è stato condotto su di un gruppo di 956 studenti delle scuole superiori, distin-guendo due diverse aree: quella delle strategie di studio e di coping nella gestione delle prove scolastiche; quella delle relazioni sociali e delle priorità in esse. Queste variabili sono state correlate con il locus of control e con le strategie di self e…
Sports teams as complex adaptive systems: manipulating player numbers shapes behaviours during football small-sided games
2016
Small-sided and conditioned games (SSCGs) in sport have been modelled as complex adaptive systems. Research has shown that the relative space per player (RSP) formulated in SSCGs can impact on emergent tactical behaviours. In this study we adopted a systems orientation to analyse how different RSP values, obtained through manipulations of player numbers, influenced four measures of interpersonal coordination observed during performance in SSCGs. For this purpose we calculated positional data (GPS 15 Hz) from ten U-15 football players performing in three SSCGs varying in player numbers (3v3, 4v4 and 5v5). Key measures of SSCG system behaviours included values of (1) players’ dispersion, (2) …