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rss_1.0 Clasificación por Disciplina

Nomenclatura Unesco > (22) Física > (2209) Óptica
(2209.01) Espectroscopía de absorción (2209.02) Cinematografía
(2209.03) Colorimetría (2209.04) Espectroscopía de emisión
(2209.05) Fibras ópticas (2209.06) Óptica geométrica
(2209.07) Holografía (2209.08) Iluminación
(2209.09) Radiación infrarroja (2209.10) Láseres
(2209.11) Luz (2209.12) Microscopios
(2209.13) Óptica no lineal (2209.14) Propiedades ópticas de los sólidos
(2209.15) Optometría (2209.16) Instrumentos fotográficos
(2209.17) Fotografía (2209.18) Fotometría
(2209.19) Óptica física (2209.20) Radiometría
(2209.21) Espectroscopía (2209.22) Radiación ultravioleta
(2209.23) Radiación visible (2209.24) Física de la visión
(2209.90) Tratamiento digital. Imágenes (2209.99) Otras (especificar)

Categorías relacionadas:
(3311.11) Instrumentos ópticos

Mostrando recursos 1 - 20 de 24,585

1. Optimum CSPR evaluation of heterodyne envelope receivers in OFDM-PONs - Behnam Shariati, Mohammad; Cano Valadéz, Iván Nicolás; Santos Blanco, M. Concepción
A heterodyne envelope (HE) receiver (RX) is investigated in the context of orthogonal frequency division multiplexing (OFDM) passive optical networks (PONs). Impacts of limited roll-off factor of shaping filter and required guard-band (GB) are studied through numerical simulations, showing that the Carrier to Signal Power Ratio (CSPR) value plays a significant role in the systems performance. For a QPSK system with 10 Gbps bitrate and for a bit error ratio (BER) quality threshold of 10-3 we show an improvement of 10.8 dB in sensitivity and 25% in spectral efficiency by using an optimum CSPR value as compared to unity CSPR.

2. Direct phase modulation of a DFB laser for udWDM-PON - Cano Valadéz, Iván Nicolás; Lerin De La Santisima Trinidad, Adolfo; Polo Querol, Víctor; Prat Gomà, Josep Joan
The response of a DFB was equalized with a simple RC network for modulating directly its phase and producing a BPSK signal. The system was tested with a heterodyne coherent detector at 1.25 Gb/s and 2.5 Gb/s showing a sensitivity penalty of around 1dB when compared with external phase modulation. The results indicate that the technique could be considered as a reliable low-cost ONU transmitter solution in udWDM-PONs.

3. OPTIMIZACION DE UN RECONOCEDOR DE TEXTO MANUSCRITO POR MEDIO DE MAPAS AUTOORGANIZADOS DE KOHONEN (RNA�s). - Gómez Valencia, Juan Diego
This text describes an application more than the nets artificial neuronals and its great capacity for the memorization of patterns. In this occasion a structure neuronal of Kohonen is implemented that it is trained so that each one of the letters of the alphabet can identify (uppercase), which are given of pulse and the own user's letter by means of an entrance peripheral as optic pencil or mouse. The applications were programmed in C++ using the bookstore Allegro.

4. Incesto de la pareja procreadora incaica como culturologema identitario en la literatura ecuatoriana - Órzhytskyi, Ígor
  La novela de Gustavo Alfredo Jácome, aparecida en 1979, es tal vez una obra única para su época, para su país y, más ampliamente, para toda la región andina, al presentar una nueva dimensión del indigenismo literario. Por primera vez en esas literaturas, sale al escenario un intelectual quechua consciente de su misión y orgulloso de sus raíces ancestrales. Sin desechar problemas sociales que sirven de fondo de la acción, el autor pasa al nivel creativo más alto, demostrando cómo las tensiones sociales se interiorizan, destacando lo ético, lo íntimo, lo sicológico e incluso, sicolingüístico ocasionado por una sociedad...

5. La externalización del apoyo logístico desde la óptica de las Fuerzas Armadas - Del Castillo Masete, Juan Antonio

6. Detecção do movimento de veículos com deslocação simultânea do sujeito - Santos, Jorge Almeida
A capacidade de detectar alterações na velocidade de outros veículos é essencial para o evitamento de colisões e a manutenção de distâncias de segurança. O tempo de reacção em situações de conflito potencial é normalmente considerado como fixo e independente das situações específicas. Porém, existe alguma evidência empírica de que o fluxo óptico global, gerado pela deslocação do sujeito, afecta a detecção de objectos em movimento. Nomeadamente os tempos de detecção aumentariam devido ao problemas acrescidos de segmentação do objecto, provocados pela percepção de movimento próprio. Neste texto são apresentados dados preliminares de uma investigação laboratorial sobre o efeito de diferentes velocidades de deslocação do sujeito, na detecção do movimento de um veículo automóvel.

7. Laser linewidth requirements for remote heterodyne OFDM based PON scenario - Escayola Elias, Francisco Javier; Cano Valadéz, Iván Nicolás; Santos Blanco, M. Concepción; Prat Gomà, Josep Joan
The relationship between the FFT size, modulation format and laser linewidth is studied in a remote heterodyne scenario where phase noise is compensated by pilot tones. Results indicate that the laser linewidth tolerance directly depends on the bandwidth per subcarrier.

8. Layer 2 redesign for Metro-Access next generation PON - López Pastor, Eduardo Tommy; Polo Querol, Víctor; Lázaro Villa, José Antonio; Prat Gomà, Josep Joan
Necessary modifications and extensions into Layer 2 of the actual PON access are necessary in order to meet new requirements from services providers and users. We propose a flexible Transmission Convergence (TC) Layer architecture for Metro-Access next generation long-reach Greenfield really-passive PON network, compatible with GPON/XGPON and with support for multi-operator/multi-service at internetworking multilevel. This proposed architecture provides future Access-Core integration network.

9. Performance evaluation of an all-optical OCS/OPS-Based network for intra-data center connectivity services - Pagès Cruz, Albert; Jimenez Feijoo, Sergio; Perelló Muntan, Jordi; Spadaro, Salvatore
As the size of Data Centers (DCs) and the amount of information managed by them grows, nowadays electronic-based intra-Data Center Networks (DCNs) start to become a limiting factor, not providing enough scalability nor flexibility to support highly dynamic traffic profiles. The LIGHTNESS intra-DCN solution, based on a hybrid all-optical OCS/OPS architecture, aims to overcome such limitations, providing an architecture suitable for the management of both long- and short-lived traffic flows. In this paper, we evaluate the performance of such a hybrid architecture in terms of blocking probability for various traffic conditions, highlighting its benefits against pure OCS or OPS networks.

10. Algunas consideraciones sobre la utilización del espacio en la clase - Lledó Becerra, Angel Ignacio; Cano Ortiz, María Isabel
El presente artículo pretende realizar desde la óptica del maestro, una reflexión acerca de la organización y utilización del espacio escolar. Basado en una experiencia más general de Pedagogía Operativa llevada a cabo durante los dos cursos del Ciclo Inicial de la EGB, trata, en primer lugar, la necesidad de plantearse el espacio escolar como un elemento en sí mismo, facilitador de la acción educativa, y, por ello, en consonancia con las opciones educativas elegidas por el maestro. Más adelante relata la experiencia llevada por los autores con respecto a este tema en sus aulas proponiendo un esquema de intervención...

11. Ideas previas en óptica geométrica: un estudio descriptivo - Nievas Cazorla, Francisco; Perales Palacios, Francisco Javier

12. La auditoria forense como herramienta en la determinación de la responsabilidad administrativa, aplicado en la fase de potestad investigativa en los órganos de control fiscal de la república - López Cañizalez, Rafael Angel
El presente trabajo tiene como propósito examinar y analizar la Auditoría Forense como Herramienta en la Determinación de Responsabilidad Administrativa, aplicado en la Fase de Potestad Investigativa en los Órganos de Control Fiscal de la República Bolivariana de Venezuela. El estudio se abordó desde la óptica de una investigación de tipo Documental Bibliográfico de nivel descriptivo; visto que se apoyó principalmente, en trabajos previos, información y medios impresos, audiovisuales o electrónico~. Los datos recolectados se interpretaron mediante las técnicas del resumen analítico y el análisis crítico, para ser presentados a través de cuadros y matrices comparativas. Entre las conclusiones más...

13. Lineal illuminating system for automatic x-y graphic colorimetric and texture testing - Gómez Pedrero, José Antonio; Peñaranda, José Antonio; Bernabeu Martínez, Eusebio
A lineal illuminating system based on an optical fiber array is studied. It can be applied to automatic industrial inspection systems, e.g., those used for chromatic classification of ceramic floor tiles. Improvement in the existing system’s performance is achieved by using a collimated beam, as shown by both photometric analysis and experimental results. This system has been implemented as part of a real-time controlling tool in a production line.

14. Planar optical array with a spatial-integration feature - Vázquez Molini, Daniel; Alda, Javier; Bernabeu Martínez, Eusebio
A planar optical array is presented that provides a selective concentration of the light incident upon the system onto a given area. Several alternative designs are analyzed and explained geometrically. The photometric calculation is presented for three different levels of approximation. A prototype of the proposed system is tested, showing good accordance with the theoretical predictions.

15. Measurement of the degree of salinity of water with a fiber-optic sensor - Esteban Martínez, Óscar; Navarrete Fernández, María Cruz; González Cano, Agustín; Bernabeu Martínez, Eusebio
A fiber-optic sensor based on surface-plasmon resonance for the determination of the refractive index is used for measuring the degree of salinity of water. The transducing element consists of a multilayer structure deposited on a side-polished monomode optical fiber. Measuring the attenuation of the power transmitted by the fiber shows that a linear relation with the refractive index of the outer medium of the structure is obtained. The system is characterized by use of a varying refractive index obtained with a mixture of water and ethylene glycol. Experimental results show that the sensor can be used as a salinity-degree measurement...

16. Outward bound, or, Young America afloat : a story of travel and adventure / - Optic, Oliver, 1822-1897.
Mode of access: Internet.

17. Strange sights abroad or, a voyage in European water / - Optic, Oliver, 1822-1897.
Mode of access: Internet.

18. Brave Old Salt, or, Life on the quarter deck : a story of the Great Rebellion / - Optic, Oliver, 1822-1897.; Lee and Shepard, publisher.
Mode of access: Internet.

19. Palace and cottage; or, Young America in France and Switzerland : a story of travel and adventure / - Optic, Oliver, 1822-1897.
Added illustrated title-page.

20. Shamrock and thistle, or, Young America in Ireland and Scotland : a story of travel and adventure / - Optic, Oliver, 1822-1897.
Added t. p., illustrated.

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