Showing papers on "Data acquisition published in 2005"

Design Aspects for Wide-Area Monitoring and Control Systems

Abstract: This paper discusses the basic design and special applications of wide-area monitoring and control systems, which complement classical protection systems and Supervisory Control and Data Acquisition/Energy Management System applications. Systemwide installed phasor measurement units send their measured data to a central computer, where snapshots of the dynamic system behavior are made available online. This new quality of system information opens up a wide range of new applications to assess and actively maintain system's stability in case of voltage, angle or frequency instability, thermal overload, and oscillations. Recent developed algorithms and their design for these application areas are introduced. With practical examples, the benefits in terms of system security are shown.

Asynchronous optical sampling terahertz time-domain spectroscopy for ultrahigh spectral resolution and rapid data acquisition

Abstract: We propose a terahertz time-domain spectrometer based on asynchronous optical sampling. The spectrometer features ultrahigh spectral resolution equivalent to a laser mode-locked frequency and rapid data acquisition. The proposed method requires no mechanical translation stages for time-delay scanning, and hence, overcomes the inherent tradeoff between frequency resolution and data acquisition time. Time evolution of the picosecond terahertz pulse with a temporal window of 12.1 ns is measured directly on an oscilloscope using a time-scale magnification of 764 815. A frequency resolution of 82.6 MHz is achieved at a measurement time of 10 s. The effectiveness of the proposed method is confirmed by comparing it with conventional stage-scanning terahertz time-domain spectroscopy.

Dynamic autocalibrated parallel imaging using temporal GRAPPA (TGRAPPA).

Abstract: Current parallel imaging techniques for accelerated imaging require a fully encoded reference data set to estimate the spatial coil sensitivity information needed for reconstruction. In dynamic parallel imaging a time-interleaved acquisition scheme can be used, which eliminates the need for separately acquiring additional reference data, since the signal from directly adjacent time frames can be merged to build a set of fully encoded full-resolution reference data for coil calibration. In this work, we demonstrate that a time-interleaved sampling scheme, in combination with autocalibrated GRAPPA (referred to as TGRAPPA), allows one to easily update the coil weights for the GRAPPA algorithm dynamically, thereby improving the acquisition efficiency. This method may update coil sensitivity estimates frame by frame, thereby tracking changes in relative coil sensitivities that may occur during the data acquisition. Magn Reson Med 53:981–985, 2005. Published 2005 Wiley-Liss, Inc. †

System, method and apparatus for capturing telematics data with an active rfid tag

Abstract: The invention is directed to a data collection and evaluation system that includes an active RFID tag for collecting, time-stamping, and storing vehicle sensor data. Examples of the type of data collected include door data, ignition data, oil pressure data, temperature data, speed data, global positioning data, and diagnostic and trouble code data. The system further includes an external data acquisition device, such as a mainframe computer system or a hand-held data acquisition device like an iPAQ. The external data acquisition device includes an RFID interrogator for communicating with the RFID tag, which enables the RFID tag to transmit the time-stamped data wirelessly to the external data acquisition device. The ability of the system to automatically collect and transfer data allows for the automation of fleet management processes, vehicle maintenance and repair processes, and certain security features.

Snapshot queries: towards data-centric sensor networks

Abstract: In this paper we introduce the idea of snapshot queries for energy efficient data acquisition in sensor networks. Network nodes generate models of their surrounding environment that are used for electing, using a localized algorithm, a small set of representative nodes in the network. These representative nodes constitute a network snapshot and can be used to provide quick approximate answers to user queries while reducing substantially the energy consumption in the network. We present a detailed experimental study of our framework and algorithms, varying multiple parameters like the available memory of the sensor nodes, their transmission range, the network message loss etc. Depending on the configuration, snapshot queries provide a reduction of up to 90% in the number of nodes that need to participate in a user query.

Ultrasound research scanner for real-time synthetic aperture data acquisition

Abstract: Conventional ultrasound systems acquire ultrasound data sequentially one image line at a time. The architecture of these systems is therefore also sequential in nature and processes most of the data in a sequential pipeline. This often makes it difficult to implement radically different imaging strategies on the platforms and makes the scanners less accessible for research purposes. A system designed for imaging research flexibility is the prime concern. The possibility of sending out arbitrary signals and the storage of data from all transducer elements for 5 to 10 seconds allows clinical evaluation of synthetic aperture and 3D imaging. This paper describes a real-time system specifically designed for research purposes. The system can acquire multichannel data in real-time from multi-element ultrasound transducers, and can perform some real-time processing on the acquired data. The system is capable of performing real-time beamforming for conventional imaging methods using linear, phased, and convex arrays. Image acquisition modes can be intermixed, and this makes it possible to perform initial trials in a clinical environment with new imaging modalities for synthetic aperture imaging, 2D and 3D B-mode, and velocity imaging using advanced coded emissions. The system can be used with 128-element transducers and can excite 128 transducer elements and receive and sample data from 64 channels simultaneously at 40 MHz with 12-bit precision. Two-to-one multiplexing in receive can be used to cover 128 receive channels. Data can be beamformed in real time using the system's 80 signal processing units, or it can be stored directly in RAM. The system has 16 Gbytes RAM and can, thus, store more than 3.4 seconds of multichannel data. It is fully software programmable and its signal processing units can also be reconfigured under software control. The control of the system is done over a 100-Mbits/s Ethernet using C and Matlab. Programs for doing, e.g., B-mode imaging can be written directly in Matlab and executed on the system over the net from any workstation running Matlab. The overall system concept is presented along with its implementation and examples of B-mode and in vivo synthetic aperture flow imaging.

Motion tracking and analysis apparatus and method and system implementations thereof

Abstract: An orientation and position tracking system and method in three-dimensional space and over a period of time utilizing multiple inertial and other sensors for determining motion parameters to measure orientation and position of a moveable object. The sensors, for example vibrational and angular velocity sensors, generate signals characterizing the motion of the moveable object. The information is received by a data acquisition system and processed by a microcontroller. The data is then transmitted to an external data reception system (locally based or a global network), preferably via wireless communication. The information can then be displayed and presented to the user through a variety of means including audio, visual, and tactile. According to various embodiments, the present invention provides for a motion tracking apparatus and method for implementation in motion systems including systems to teach motion to a group and for body motion capture and analysis systems.

MeaBench: A toolset for multi-electrode data acquisition and on-line analysis

Abstract: We present a software suite, MeaBench, for data acquisition and online analysis of multi-electrode recordings, especially from micro-electrode arrays. Besides controlling data acquisition hardware, MeaBench includes algorithms for real-time stimulation artifact suppression and spike detection, as well as programs for online display of voltage traces from 60 electrodes and continuously updated spike raster plots. MeaBench features real-time output streaming, allowing easy integration with stimulator systems. We have been able to generate stimulation sequences in response to live neuronal activity with less than 20 ms lag time. MeaBench is open-source software, and is available for free public download at http://www.its.caltech.edu/~pinelab/wagenaar/meabench.html

Model-based approximate querying in sensor networks

Abstract: Declarative queries are proving to be an attractive paradigm for interacting with networks of wireless sensors. The metaphor that “the sensornet is a database” is problematic, however, because sensors do not exhaustively represent the data in the real world. In order to map the raw sensor readings onto physical reality, a model of that reality is required to complement the readings. In this article, we enrich interactive sensor querying with statistical modeling techniques. We demonstrate that such models can help provide answers that are both more meaningful, and, by introducing approximations with probabilistic confidences, significantly more efficient to compute in both time and energy. Utilizing the combination of a model and live data acquisition raises the challenging optimization problem of selecting the best sensor readings to acquire, balancing the increase in the confidence of our answer against the communication and data acquisition costs in the network. We describe an exponential time algorithm for finding the optimal solution to this optimization problem, and a polynomial-time heuristic for identifying solutions that perform well in practice. We evaluate our approach on several real-world sensor-network datasets, taking into account the real measured data and communication quality, demonstrating that our model-based approach provides a high-fidelity representation of the real phenomena and leads to significant performance gains versus traditional data acquisition techniques.

Industrial process data acquisition and analysis

Abstract: A method for optimizing an industrial process data is disclosed. The method includes collecting data from a plurality of sensor elements, wherein each sensor element collects data from a portion of the industrial process and verifying the data collected. The method further includes analyzing the data collected for efficiency and generating at least one recommendation for optimizing the industrial process. The method further includes presenting the at least one recommendation generated to an administrator of the industrial process.

A high-performance EIT system

Abstract: This paper presents the development of a new electrical impedance tomography system for online measurement of two-phase flows with axial velocities up to 10 ms/sup -1/. The system is designed in a modular fashion and can consist of several data acquisition modules and computing modules. The data acquisition module includes a voltage controlled current source with a direct-current-restoration circuit, an equal-width pulse synthesizer unit and a synchronized digital demodulation unit. A new concept of current switching scheme is developed to enhance the ac coupling speed. The computing module includes a digital signal processor (TMS320C6202/6713) with memory, multichannel buffered serial ports and an IEEE1394 communication interface. Several DSP modules can be pipelined for a series of tasks ranging from measurement control to image reconstruction to flow velocity implementation. The performances have been tested and some trial results are reported. A data acquisition speed of 1164 dual-frames (2.383 million data points) per second has been achieved with a root mean square error less than 0.6% at 80 kHz in static test application. An application in the measurement of vertical oil-in-water pipe flow is reported.

A GLRT approach to data-aided timing acquisition in UWB radios-Part I: algorithms

Abstract: Realizing the great potential of impulse radio communications depends critically on the success of timing acquisition. To this end, optimum data-aided (DA) timing offset estimators are derived in this paper based on the maximum likelihood (ML) criterion. Specifically, generalized likelihood ratio tests (GLRTs) are employed to detect an ultrawideband (UWB) waveform propagating through dense multipath and to estimate the associated timing and channel parameters in closed form. Capitalizing on the pulse repetition pattern, the GLRT boils down to an amplitude estimation problem, based on which closed-form timing acquisition estimates can be obtained without invoking any line search. The proposed algorithms only employ digital samples collected at a low symbol rate, thus reducing considerably the implementation complexity and acquisition time. Analytical acquisition performance bounds and corroborating simulations are also provided.

Use of novel adaptive digital feedback for magnetic measurements under controlled magnetizing conditions

Abstract: There are increasing calls to employ conventional magnetic testers, such as the Epstein frame and single sheet tester, for the accurate measurements of magnetic properties of soft magnetic materials under fully controlled nonsinusoidal flux density waveforms. This paper presents a computerized automated adaptive digital feedback system built for that purpose. We present several examples of the ability of the system to control an arbitrary shape of the flux density waveforms over the frequency range of the data acquisition system (0.5 Hz to 2 kHz) and for peak flux density up to 90% of saturation. The control algorithm is capable of magnetizing magnetic material under controlled sinusoidal, triangular, trapezoidal, and pulsewidth-modulated magnetizing conditions as well as other arbitrary waveforms that do not contain dc components. We provide a full description of the adaptive digital feedback technique together with measurements showing the B-H loops for several magnetic materials under various controlled excitation conditions.

Improved data acquisition in grazing-incidence X-ray scattering experiments using a pixel detector

Abstract: The use of an area detector in grazing-incidence X-ray experiments lends many advantages in terms of both speed and reliability. Here a discussion is given of the procedures established using the PILATUS pixel detector developed at the Swiss Light Source for optimizing data acquisition and analysis of surface diffraction data at the Materials Science beamline, especially with regard to reflectivity measurements, crystal truncation and fractional order rods, and grazing-incidence diffraction experiments.

Method and apparatus for improving performance of noninvasive analyte property estimation

Abstract: The invention relates to noninvasive analyte property determination. More particularly, the invention relates to a method and apparatus for performing conditional additional acquisition of noninvasive spectra to improve analyzer performance. Conditional additional data acquisition is used to confirm, update, and/or supplement spectral data.

The data acquisition system of the neutron time-of-flight facility n_TOF at CERN

Abstract: The n_TOF facility at CERN has been designed for the measurement of neutron capture, fission and (n, xn) cross-sections with high accuracy. This requires a flexible and-due to the high instantaneous neutron flux-almost dead time free data acquisition system. A scalable and versatile data solution has been designed based on 8-bit flash-ADCs with sampling rates up to 2 GHz and 8 Mbyte memory buffer. The software is written in C and C++ and is running on PCs equipped with RedHat Linux.

Data acquisition system for high speed atomic force microscopy

Abstract: With the development of atomic force microscopes that allow higher scan speeds, the need for data acquisition systems (DAQ) that are capable of handling the increased amounts of data in real time arises We have developed a low cost data acquisition and scan control system around a commercially available DAQ board in a WINDOWS environment By minimizing the involvement of the processor in the data transfer using direct memory access, and generation of the scan signals synchronously with the data acquisition, we were able to record 30 frames per second with a pixel resolution of 150×150pixels and 14bit per channel

System and method for signal processing for a workpiece surface inspection

Abstract: A surface inspection system, as well as related components and methods, are provided. The surface inspection system includes a beam source subsystem, a beam scanning subsystem, a workpiece movement subsystem, an optical collection and detection subsystem, and a processing subsystem. The signal processing subsystem comprises a series of data acquisition nodes, each dedicated to a collection detection module and a plurality of data reduction nodes, made available on a peer to peer basis to each data acquisition nodes. Improved methods for detecting signal in the presence of noise are also provided.

Vector-sensor MUSIC for polarized seismic sources localization

Abstract: This paper addresses the problem of high-resolution polarized source detection and introduces a new eigenstructure-based algorithm that yields direction of arrival (DOA) and polarization estimates using a vector-sensor (or multicomponent-sensor) array. This method is based on separation of the observation space into signal and noise subspaces using fourth-order tensor decomposition. In geophysics, in particular for reservoir acquisition and monitoring, a set of Nx-multicomponent sensors is laid on the ground with constant distance Δx between them. Such a data acquisition scheme has intrinsically three modes: time, distance, and components. The proposed method needs multilinear algebra in order to preserve data structure and avoid reorganization. The data is thus stored in tridimensional arrays rather than matrices. Higher-order eigenvalue decomposition (HOEVD) for fourth-order tensors is considered to achieve subspaces estimation and to compute the eigenelements. We propose a tensorial version of the MUSIC algorithm for a vector-sensor array allowing a joint estimation of DOA and signal polarization estimation. Performances of the proposed algorithm are evaluated.

Hands-free data acquisition system

Abstract: A wearable data acquisition system is described in which the data input devices are contained within a headpiece apparatus thereby permitting the operator to control acquisition integration of image capture and display in a hands free environment. The system includes a portable data terminal communicating with the headpiece apparatus which comprises an image acquisition device having a target pattern generator for providing visual feedback for aiming and range-finding, a microphone for receiving voice commands from a human operator to the portable data terminal, and a speaker whereby the human operator receives audio feedback from the portable data terminal. In another embodiment of the present invention, the headpiece apparatus further comprises an image display system having a scanning laser heads-up display for projecting image data into the vision field of the human operator. This image display system allows the human operator to preview an image to be captured or to recall stored image data from the memory of the portable data terminal.

Multi-channel electrophysiologic signal data acquisition system on an integrated circuit

Abstract: A physiologic data acquisition system includes an analog input, a sigma-delta front end signal conditioning circuit adapted to subtract out DC and low frequency interfering signals from and amplify the analog input before analog to digital conversion. The system can be programmed to acquire a selected physiologic signal, e.g., a physiologic signal characteristic of or originating from a particular biological tissue. The physiologic data acquisition system may include a network interface modulating a plurality of subcarriers with respective portions of an acquired physiologic signal. A receiver coupled to the network interface can receive physiologic data from, and send control signals and provide power to the physiologic data acquisition system over a single pair of wires. The network interface can modulate an RF carrier with the plurality of modulated subcarriers and transmit the resulting signal to the receiver across a wireless network. An integrated circuit may include the physiologic data acquisition system. Also included are methods for acquiring physiologic data comprising the step of selectively controlling an acquisition circuit to acquire the physiologic signal.

Data acquisition in multiple-sink sensor networks

Abstract: Scalable, energy-efficient data acquisition in large sensor network deployments such as habitat monitoring is an research important problem. In several papers [1, 2], sensor networks have been modeled as having a single sink (or base-station) that acts as the data recipient for a large number of sensors (data sources) deployed over a sensor field. The sensor network might use simple querying and data collection trees for hop-by-hop query dissemination and routing of sensor responses [1] back towards the sink. Since sensors are energy-constrained devices, we wish to minimize communication energy expenditure of these sensors.

Evaluation of high performance data acquisition boards for simultaneous sampling of fast signals from PET detectors

Abstract: Detectors used for positron emission tomography (PET) provide fast, randomly distributed signals that need to be digitized for further processing. One possibility is to sample the signals at the peak initiated by a trigger from a constant fraction discriminator (CFD). For PET detectors, simultaneous acquisition of many channels is often important. To develop and evaluate novel PET detectors, a flexible, relatively low cost and high performance laboratory data acquisition (DAQ) system is therefore required. The use of dedicated DAQ systems, such as a multi-channel analysers (MCAs) or continuous sampling boards at high rates, is expensive. This work evaluates the suitability of well-priced peripheral component interconnect (PCI)-based 8-channel DAQ boards (PD2-MFS-8 2M/14 and PD2-MFS-8-500k/14, United Electronic Industries Inc., Canton, MA, USA) for signal acquisition from novel PET detectors. A software package was developed to access the board, measure basic board parameters, and to acquire, visualize, and analyse energy spectra and position profiles from block detectors. The performance tests showed that the boards input linearity is >99.2% and the standard deviation is <9 mV at 10 V for constant signals. Synchronous sampling of multiple channels and external synchronization of more boards are possible at rates up to 240 kHz per channel. Signals with rise times as fast as 130 ns (<2 V amplitude) can be acquired without slew rate effects. However, for signals with amplitudes of up to 5 V, a rise time slower than 250 ns is required. The measured energy resolution of a lutetium oxyorthosilicate (LSO)-photomultiplier tube (PMT) detector with a 22Na source was 14.9% (FWHM) at 511 keV and is slightly better than the result obtained with a high-end single channel MCA (8000A, Amptek, USA) using the same detector (16.8%). The crystals (1.2 x 1.2 x 12 mm3) within a 9 x 9 LSO block detector could be clearly separated in an acquired position profile. Thus, these boards are well suited for data acquisition with novel detectors developed for nuclear imaging.

A Multi-Channel Device for Respiratory Sound Data Acquisition and Transient Detection

Abstract: In this study, a multi-channel analog data acquisition and processing device with the additional feature of detecting adventitious sounds has been designed and implemented. The overall system consists of fourteen microphones attached on the backside, an airflow measuring unit, a fifteen-channel amplifier and filter unit connected to a personal computer (PC) via a data acquisition (DAQ) card, and an interface and adventitious sound detection program prepared using LabVIEW (6.0, National Instruments) and MATLAB (7.0.1, MathWorks). The system records the fourteen-channel respiratory sound data at the posterior chest wall and in addition measures the air flow to synchronize the pulmonary signal on the respiration cycle. Respiratory data are amplified and band-pass filtered, whereas flow signal is only low-pass filtered since it is a low-frequency signal with sufficiently high amplitude. All data are sent to a PC to be digitized by DAQ card, then to be processed and stored. An algorithm based on wavelet decomposition is developed which detects the adventitious pulmonary sounds, mainly the crackles and wheezes. This system is intended to be used for mapping the pulmonary sounds and detecting and locating the adventitious pulmonary sounds

Methods and systems for controlling acquisition of images

Abstract: Systems and methods for interacting effectively with three-dimensional data are provided such that a data acquisition system of an imaging system can be guided appropriately to gather relevant information from the object being imaged. In one embodiment, the imaging system includes the data acquisition system for obtaining a three-dimensional image of the object; and a processor coupled to the data acquisition system. The processor may be configured for receiving a user interface input based on interaction with the three-dimensional image, and for providing multiple parameters to the data acquisition system based on the user interface input. These parameters may be used for further acquisition by the data acquisition system.