Real time plasma disruptions detection in JET implemented with the ITMS platform using FPGA based IDAQ

The use of FPGAs in data acquisition cards for processing purposes allows an efficient real time pattern recognition algorithm implementation. Using 13 JETs database waveforms an algorithm for detecting incoming plasma disruptions has been implemented. This algorithm is written in MATLAB using floating point representation. In this work we show the methodology used to implement the real time version of the algorithm using Intelligent Data Acquisition Cards (IDAQ), DAQ devices with field programmable gate array (FPGA) for local processing. This methodology is based on the translation of the MATLAB code to LabVIEW and the final coding of specific pieces of code in LabVIEW for FPGA in fixed point format. The whole system for evaluating the real time disruption detection (RTDD) has been implemented using the Intelligent Test and Measurement System (ITMS) platform. ITMS offers distributed data acquisition, distribution and real time processing capabilities with advanced, but easy to use, software tools that simplify application development and system setup. The RTDD implementation uses a standard PXI/PXIe architecture. Two 8 channel analog output cards play JETs database signals, two 8 channel DAQ with FPGA acquire signals and computes a feature vector based in FFT analysis. Finally the vector acquired is used by the system CPU to execute a pattern recognition algorithm to estimate an incoming disruption

New information processing methods for control in magnetically confinement nuclear fusion

Thermonuclear plasmas are complex and highly non-linear physical objects and therefore, in the most advanced present day devices for the study of magnetic confinement fusion, thousands of signals have to be acquired for each experiment, in order to progress with the understanding indispensable for the final reactor. On the other hand, the resulting massive databases, more than 40 Tbytes in the case of the JET joint Undertaking, pose significant problems. In this paper, solutions to reduce the shear amount of data by different compression techniques and adaptive sampling frequency architectures are presented. As an example of methods capable of providing significant help in the data analysis and real time control, a Classification and Regression Tree software is applied to the problem of regime identification, to discriminate in an automatic way whether the plasma is in the L or H confinement mode

Exploiting graphic processing units parallelism to improve intelligent data acquisition system performance in JET's correlation reflectometer

The performance of intelligent data acquisition systems relies heavily on their processing capabilities and local bus bandwidth, especially in applications with high sample rates or high number of channels. This is the case of the self adaptive sampling rate data acquisition system installed as a pilot experiment in KG8B correlation reflectometer at JET. The system, which is based on the ITMS platform, continuously adapts the sample rate during the acquisition depending on the signal bandwidth. In order to do so it must transfer acquired data to a memory buffer in the host processor and run heavy computational algorithms for each data block. The processing capabilities of the host CPU and the bandwidth of the PXI bus limit the maximum sample rate that can be achieved, therefore limiting the maximum bandwidth of the phenomena that can be studied. Graphic processing units (GPU) are becoming an alternative for speeding up compute intensive kernels of scientific, imaging and simulation applications. However, integrating this technology into data acquisition systems is not a straight forward step, not to mention exploiting their parallelism efficiently. This paper discusses the use of GPUs with new high speed data bus interfaces to improve the performance of the self adaptive sampling rate data acquisition system installed on JET. Integration issues are discussed and performance evaluations are presente

Transference Impedance Estimation of IEC60318 Couplers by Image Processing and finite Element Modelling

In order to know the acoustic transference impedance of acoustic coupler described in IEC60318 standard it is necessary to make measures based on the reciprocity technique. This technique is used for microphones calibration as is defined in IEC61094-2 standard. This calibration method is complex enough to execute, and therefore it would be very interesting to look for alternative procedures that allow knowing the coupler acoustic impedance. In this paper an acoustic impedance calibration methodfor type I coupler is proposed based on non invasive X-ray inspection, virtual instrumentation image processing application and computer simulation. This new approach requires knowing the coupler's geometry and use offinite element model approach for acoustic coupler behavior determination. In order to establish a precise mechanical model of the couplers described in IEC60318 standard it is necessary to know the geometry and key dimensions of the coupler. These dimensions are obtained with non-invasive measurement techniques, based on X-ray inspection. Then the use of a finite element model allows prediction of the coupler acoustic impedance values. This modeling is quite differentfrom the "lumped parameter model" proposed in the IEC60318 standard Lumped parameter modeling has limitations in its application because the dimensions of the coupler's elements are comparable with the acoustic signal wavelength. Moreover, when the sound propagates in narrow cavities and ducts the losses produced by viscosity and thermal effects must be taken into account. All these effects are not reflected with accuracy in the classic lumped model. The result of finite element simulation can provide more detailed information about the interior acoustic behavior of the coupler and therefore provide a more realistic and accurate value of acoustic impedance in order to calibrate the device. The comparison of the data obtained with this new approach and the values defined in the current version of IEC60318-1 standard (291633/CDV) confirm the validity ofthe method

Implementation of local area network extension for instrumentation standard trigger capabilities in advanced data acquisition platforms

Synchronization mechanisms are an essential part of the real-time distributed data acquisition systems (DASs) used in fusion experiments. Traditionally, they have been based on the use of digital signals. The approach known as local area network extension for instrumentation (LXI) provides a set of very powerful synchronization and trigger mechanisms. The Intelligent Test Measurement System (ITMS) is a new platform designed to implement distributed data acquisition and fast data processing for fusion experiments. It is based on COMPATPCI technology and its extension to instrumentation (PXI). Hardware and software elements have been developed to include LXI trigger and synchronization mechanisms in this platform in order to obtain a class A LXI instrument. This paper describes the implementation of such a system, involving the following components: commercial hardware running a Linux operating system; a real-time extension to an operating system and network (RTAI and RTNET), which implements a software precision time protocol (PTP) using IEEE1588; an ad hoc PXI module to support hardware implementation of PTP-IEEE 1588; and the multipoint, low-voltage differential signaling hardware LXI trigger bus. ©2008 American Institute of Physic

Awareness: A parallel approach against noise

Unlike other pollutants, many of the noise effects on people have a clear subjective component that go beyond the objective physiological effects that the physical phenomenon causes. Among them, annoyance is the most documented subjective response to noise, it being defined as a feeling of discomfort or displeasure that occurs when noise intrudes our everyday activities. For decades it has been one of the hot topics of environmental acoustics. But, while many studies have focused on the possible correlation between sound metrics and the adverse reaction of the population, the effect of non-acoustic factors on the annoyance response has recently emerged as a hot topic in international transport research groups. The aim of this paper is to present a novel approach to the assessment of noise impacts that could be of value to railway operations, complementing traditional approaches based on the reduction of exposure. Awareness comprises several non-acoustical factors pointed out in the past as affecting annoyance: information (accessibility, transparency and understanding), trust, influence/voice, attitude towards the source, predictability of the noise situation, awareness of negative effects... The project aims to obtain knowledge of this factor, analyse its influence, and take advantage of it to mitigate annoyance. This is an approach that has not been exploited in depth in the past, and does not imply the reduction of noise emissions at all, so that it can be managed together with other noise control measures. It is based on the hypothesis that "bringing information closer to residents will reduce noise annoyance", and tries to answer the following question: How does Awareness Influence Noise Annoyance? To what extent can Communication or other Non-Acoustical measures modify Awareness in order to help residents to cope with Noise

Influencia de la sensibilización sobre la percepción de la molestia

Actualmente el ruido en entornos aeroportuarios presenta unos niveles de aceptación muy bajos. Los niveles de emisión acústica de las aeronaves han decrecido notablemente en las últimas décadas y dicha mejora no ha redundado en una disminución de la molestia. En algunos aeropuertos donde se aplica el concepto de enfoque equilibrado no existe demasiado margen para la reducción en las emisiones acústicas. Una alternativa es investigar el papel que pueden desempeñar las estrategias de sensibilización y de comunicación de las emisiones acústicas por parte de los gestores del ruido, intentando responder a las siguientes cuestiones: ¿Cómo afecta la comunicación en materia de ruido sobre la percepción de molestia?, ¿Puede contribuir activamente a mejorar la aceptación de los aeropuertos?, ¿Cómo podemos hacer estas estrategias más eficaces

Configuration and supervision of advanced distribuited data adquisition and processing systems for long pulse experiments using JINI technology.

The development of tools for managing the capabilities and functionalities of distributed data acquisition systems is essential in long pulse fusion experiments. The intelligent test and measurement system (ITMS) developed by UPM and CIEMAT is a technology that permits implementation of a scalable data acquisition and processing system based on PXI or CompactPCI hardware. Several applications based on JINI technology have been developed to enable use of this platform for extensive implementation of distributed data acquisition and processing systems. JINI provides a framework for developing service-oriented, distributed applications. The applications are based on the paradigm of a JINI federation that supports mechanisms for publication, discovering, subscription, and links to remote services. The model we implemented in the ITMS platform included services in the system CPU (SCPU) and peripheral CPUs (PCPUs). The resulting system demonstrated the following capabilities: (1) setup of the data acquisition and processing to apply to the signals, (2) information about the evolution of the data acquisition, (3) information about the applied data processing and (4) detection and distribution of the events detected by the ITMS software applications. With this approach, software applications running on the ITMS platform can be understood, from the perspective of their implementation details, as a set of dynamic, accessible, and transparent services. The search for services is performed using the publication and subscription mechanisms of the JINI specification. The configuration and supervision applications were developed using remotely accessible (LAN or WAN) objects. The consequence of this approach is a hardware and software architecture that provides a transparent model of remote configuration and supervision, and thereby a means to simplify the implementation of a distributed data acquisition system with scalable and dynamic local processing capability developed in a fusion environment

Self-adaptive sampling rate data acquisition in JET’s correlation reflectometer

Data acquisition systems with self-adaptive sampling rate capabilities have been proposed as a solution to reduce the shear amount of data collected in every discharge of present fusion devices. This paper discusses the design of such a system for its use in the KG8B correlation reflectometer at JET. The system, which is based on the ITMS platform, continuously adapts the sample rate during the acquisition depending on the signal bandwidth. Data are acquired continuously at the expected maximum sample rate and transferred to a memory buffer in the host processor. Thereafter the rest of the process is based on software. Data are read from the memory buffer in blocks and for each block an intelligent decimation algorithm is applied. The decimation algorithm determines the signal bandwidth for each block in order to choose the optimum sample rate for that block, and from there the decimation factor to be used. Memory buffers are used to adapt the throughput of the three main software modules _data acquisition, processing, and storage_ following a typical producer-consumer architecture. The system optimizes the amount of data collected while maintaining the same information. Design issues are discussed and results of performance evaluation are presented