Diseño de los sistemas de comunicación en plantas de exploración y producción de hidrocarburos

Las plantas industriales de exploración y producción de petróleo y gas disponen de numerosos sistemas de comunicación que permiten el correcto funcionamiento de los procesos que tienen lugar en ella así como la seguridad de la propia planta. Para el presente Proyecto Fin de Carrera se ha llevado a cabo el diseño del sistema de megafonía PAGA (Public Address and General Alarm) y del circuito cerrado de televisión (CCTV) en la unidad de procesos Hydrocrcaker encargada del craqueo de hidrógeno. Partiendo de los requisitos definidos por las especificaciones corporativas de los grupos petroleros para ambos sistemas, PAGA y CCTV, se han expuesto los principios teóricos sobre los que se fundamenta cada uno de ellos y las pautas a seguir para el diseño y demostración del buen funcionamiento a partir de software específico. Se ha empleado las siguientes herramientas software: EASE para la simulación acústica, PSpice para la simulación eléctrica de las etapas de amplificación en la megafonía; y JVSG para el diseño de CCTV. La sonorización tanto de las unidades como del resto de instalaciones interiores ha de garantizar la inteligibilidad de los mensajes transmitidos. La realización de una simulación acústica permite conocer cómo va a ser el comportamiento de la megafonía sin necesidad de instalar el sistema, lo cual es muy útil para este tipo de proyectos cuya ingeniería se realiza previamente a la construcción de la planta. Además se comprueba el correcto diseño de las etapas de amplificación basadas en líneas de alta impedancia o de tensión constante (100 V). El circuito cerrado de televisión (CCTV) garantiza la transmisión de señales visuales de todos los accesos a las instalaciones y unidades de la planta así como la visión en tiempo real del correcto funcionamiento de los procesos químicos llevados a cabo en la refinería. El sistema dispone de puestos de control remoto para el manejo y gestión de las cámaras desplegadas; y de un sistema de almacenamiento de las grabaciones en discos duros (RAID-5) a través de una red SAN (Storage Area Network). Se especifican las diferentes fases de un proyecto de ingeniería en el sector de E&P de hidrocarburos entre las que se destaca: propuesta y adquisición, reunión de arranque (KOM, Kick Off Meeting), estudio in situ (Site Survey), plan de proyecto, diseño y documentación, procedimientos de pruebas, instalación, puesta en marcha y aceptaciones del sistema. Se opta por utilizar terminología inglesa dado al ámbito global del sector. En la última parte del proyecto se presenta un presupuesto aproximado de los materiales empleados en el diseño de PAGA y CCTV. ABSTRACT. Integrated communications for Oil and Gas allows reducing risks, improving productivity, reducing costs, and countering threats to safety and security. Both PAGA system (Public Address and General Alarm) and Closed Circuit Television have been designed for this project in order to ensure a reliable security of an oil refinery. Based on the requirements defined by corporate specifications for both systems (PAGA and CCTV), theoretical principles have been presented as well as the guidelines for the design and demonstration of a reliable design. The following software has been used: EASE for acoustic simulation; PSpice for simulation of the megaphony amplification loops; and JVSG tool for CCTV design. Acoustic for both the units and the other indoor facilities must ensure intelligibility of the transmitted messages. An acoustic simulation allows us to know how will be the performance of the PAGA system without installing loudspeakers, which is very useful for this type of project whose engineering is performed prior to the construction of the plant. Furthermore, it has been verified the correct design of the amplifier stages based on high impedance lines or constant voltage (100 V). Closed circuit television (CCTV) ensures the transmission of visual signals of all access to facilities as well as real-time view of the proper functioning of chemical processes carried out at the refinery. The system has remote control stations for the handling and management of deployed cameras. It is also included a storage system of the recordings on hard drives (RAID - 5) through a SAN (Storage Area Network). Phases of an engineering project in Oil and Gas are defined in the current project. It includes: proposal and acquisition, kick-off meeting (KOM), Site Survey, project plan, design and documentation, testing procedures (SAT and FAT), installation, commissioning and acceptance of the systems. Finally, it has been presented an estimate budget of the materials used in the design of PAGA and CCTV.

Estimation of functional connectivity from electromagnetic signals and the amount of empirical data required

An increasing number of neuroimaging studies are concerned with the identification of interactions or statistical dependencies between brain areas. Dependencies between the activities of different brain regions can be quantified with functional connectivity measures such as the cross-correlation coefficient. An important factor limiting the accuracy of such measures is the amount of empirical data available. For event-related protocols, the amount of data also affects the temporal resolution of the analysis. We use analytical expressions to calculate the amount of empirical data needed to establish whether a certain level of dependency is significant when the time series are autocorrelated, as is the case for biological signals. These analytical results are then contrasted with estimates from simulations based on real data recorded with magnetoencephalography during a resting-state paradigm and during the presentation of visual stimuli. Results indicate that, for broadband signals, 50–100 s of data is required to detect a true underlying cross-correlations coefficient of 0.05. This corresponds to a resolution of a few hundred milliseconds for typical event-related recordings. The required time window increases for narrow band signals as frequency decreases. For instance, approximately 3 times as much data is necessary for signals in the alpha band. Important implications can be derived for the design and interpretation of experiments to characterize weak interactions, which are potentially important for brain processing.

A new feature extraction method for signal classification applied to cat spinal cord signals

In the spinal cord of the anesthetized cat, spontaneous cord dorsum potentials (CDPs) appear synchronously along the lumbo-sacral segments. These CDPs have different shapes and magnitudes. Previous work has indicated that some CDPs appear to be specially associated with the activation of spinal pathways that lead to primary afferent depolarization and presynaptic inhibition. Visual detection and classification of these CDPs provides relevant information on the functional organization of the neural networks involved in the control of sensory information and allows the characterization of the changes produced by acute nerve and spinal lesions. We now present a novel feature extraction approach for signal classification, applied to CDP detection. The method is based on an intuitive procedure. We first remove by convolution the noise from the CDPs recorded in each given spinal segment. Then, we assign a coefficient for each main local maximum of the signal using its amplitude and distance to the most important maximum of the signal. These coefficients will be the input for the subsequent classification algorithm. In particular, we employ gradient boosting classification trees. This combination of approaches allows a faster and more accurate discrimination of CDPs than is obtained by other methods.

Photonic processing subsystem based on visual cortex architecture

Optical signal processing in any living being is more complex than the one obtained in artificial systems. Cortex architecture, although only partly known, gives some useful ideas to be employed in communications. To analyze some of these structures is the objective of this paper. One of the main possibilities reported is handling signals in a parallel way. As it is shown, according to the signal characteristics each signal impinging onto a single input may be routed to a different output. At the same time, identical signals, coming to different inputs, may be routed to the same output without internal conflicts. This is due to the change of some of their characteristics in the way out when going through the intermediate levels. The simulation of this architecture is based on simple logic cells. The basis for the proposed architecture is the five layers of the mammalian retina and the first levels of the visual cortex.