On-line Data Reduction Research Articles

Affordable sleep estimates using micro-electro-mechanical-systems (MEMS) accelerometry

Although more aff¬ordable than polysomnography, actigraphic sleep estimates have disadvantages. Brand-specific differences in data reduction impede pooling of data for consortia to create large-scale cohorts, as for genome-wide-association-studies (GWAS). Secondly, online data reduction may not fully exploit movement information. Thirdly, sleep estimate reliability might improve by advanced analyses of tri-axial, linear accelerometry data sampled at a high rate. Such recordings are now feasible using affordable micro-electro-mechanical-systems (MEMS). However, it might take a while before advanced analyses are validated and available. PURPOSE: To provide lab-databases and ongoing studies with backward compatibility when switching from actigraphy to MEMS accelerometry, we designed and validated a method to transform accelerometry data into the traditional actigraphic ‘movement counts’, thus allowing for the use of validated algorithms to estimate sleep parameters. Simultaneous duplicate actigraphy and duplicate MEMS-accelerometry was recorded in fifteen healthy adults (23–36 years, 10 M, 5F) during one night spent at home. Actigraphy was recorded as ‘movement counts 15-s epoch with two Actiwatches (Cambridge Neurotechnology Ltd., Cambridge, UK and Mini Mitter, Respironics Inc., Bend, OR, USA). MEMS-accelerometry was digitized at 50 Hz with two Geneactivs (ActivInsights Ltd., Kimbolton, UK). Passing-Bablok regression was used to optimize the transformation of MEMS-accelerometry signals to ‘movement counts’. Actigraphic ‘movement counts’ and their MEMS-accelerometry estimates were used to calculate common sleep parameters. Reliability was evaluated both between and within the traditional actigraphs and MEMS-accelerometers using Bland–Altman plots. Movement counts could be estimated from MEMS-accelerometry with high precision. MEMS-accelerometry had a better reliability than actigraphy; sleep parameter estimate agreement between two MEMS-accelerometers or a MEMS-accelerometer and an actigraph was better than agreement between two actigraphs. The algorithm allows for continuity of outcome parameters in ongoing actigraphy studies that consider switching to the new generation of MEMS-accelerometers. Their affordability and the algorithm with graphical-user-interface we here provide, makes objective sleep estimates in large-scale twin-sibling and GWAS cohort designs feasible. Detailed results as well as instructions to get the free stand-alone Matlab-based interface to convert 3D signal to movement counts and obtain actigraphic sleep estimates are given in: te Lindert BHW and Van Someren EJW (2013) Affordable sleep estimates using micro electro-mechanical systems (MEMS) accelerometry. Sleep 36:781–789. Supported by: Project NeuroSIPE 10 738, of the Dutch Technology Foundation STW, which is part of the Netherlands Organization for Scientific Research (NWO) and partly funded by the Ministry of Economic Aff¬airs, Agriculture and Innovation; and by the VICI Innovation Grant 453-07-001 of the Netherlands Organization of Scientific Research (NWO); The Hague, the Netherlands.

A simple point cloud data reduction method based on Akima spline interpolation for digital copying manufacture

Point cloud data acquisition is the first key step in digital copying manufacture. In order to reduce extremely dense acquired data while maintaining data accuracy, this paper presents a simple and practical on-line point cloud data reduction method for digital copying manufacture, which is based on Akima spline interpolation. The basic idea of this method is similar to sketch painting: Outline the broad contour of the curve first and then revise local details until the interpolated curve satisfies the required accuracy. In this method, Akima spline interpolation is adopted to connect acquired points for CNC machining in digital copying process. It obtains a smaller data reduction ratio and a smoother machined surface than conventional methods. Experimental results indicate that the proposed Akima reduction method is able to eliminate redundant data effectively under different required accuracy. The reduction performance of this method is superior to equal ATCD reduction method obviously under the same required accuracy. The proposed method can be used in the real-time data acquisition process of digital copying manufacture to replace traditional methods.

Multiple optimized online support vector regression for adaptive time series prediction

Data-driven prognostics based on sensor or historical test data have become appropriate prediction means in prognostics and health management (PHM) application. However, most traditional data-driven prognostics methods are off-line which would be seriously limited in many PHM systems needed on-line predicting or real-time processing. Furthermore, even in some on-line prediction algorithms such as Online Support Vector Regression (Online SVR) and Incremental learning algorithm, there are conflicts and trade-offs between prediction efficiency and accuracy. Therefore, in different PHM applications, prognostics algorithms should be on-line, flexible and adaptive to balance the prediction efficiency and accuracy. An on-line adaptive data-driven prognostics strategy is proposed with five various optimized on-line prediction algorithms based on Online SVR. These five algorithms are improved with kernel combination and sample reduction to realize higher precision and efficiency. These algorithms can achieve more accurate results by data pre-processing and model optimization, moreover, faster operating speed and lower computational complexity can be obtained by optimization of training process with on-line data reduction. With these different improved Online SVR methods, varies of prediction with different precision and efficiency demands could be fulfilled by an adaptive strategy. To evaluate the proposed prognostics strategy, we have executed simulation experiments with Tennessee Eastman (TE) process. In addition, the prediction strategies are also applied and evaluated by traffic mobile communication data from China Mobile Communications Corporation Heilongjiang Co., Ltd. Experiments and test results prove its effectiveness and confirm that the algorithms can be effectively applied to the on-line status prediction with increased performance in both precision and efficiency.

FPGA-based architecture for real-time data reduction of ultrasound signals

This paper describes a novel method for on-line real-time data reduction of radiofrequency (RF) ultrasound signals. The approach is based on a field programmable gate array (FPGA) system intended mainly for steel thickness measurements. Ultrasound data reduction is desirable when: (1) direct measurements performed by an operator are not accessible; (2) it is required to store a considerable amount of data; (3) the application requires measuring at very high speeds; and (4) the physical space for the embedded hardware is limited. All the aforementioned scenarios can be present in applications such as pipeline inspection where data reduction is traditionally performed on-line using pipeline inspection gauges (PIG). The method proposed in this work consists of identifying and storing in real-time only the time of occurrence (TOO) and the maximum amplitude of each echo present in a given RF ultrasound signal. The method is tested with a dedicated immersion system where a significant data reduction with an average of 96.5% is achieved.

A Novel Phase Congruency Based Algorithm for Online Data Reduction in Ambulatory EEG Systems

Real signals are often corrupted by noise with a power spectrum variable over time. In applications involving these signals, it is expected that dynamically estimating and correcting for this noise would increase the amount of useful information extracted from the signal. One such application is scalp EEG monitoring in epilepsy, where electrical activity generated by cranio-facial muscles obscure the measured brainwaves. This paper presents a data-selection algorithm based on phase congruency to identify interictal spikes from background EEG; together with a novel statistical method that allows a more comprehensive trade-off based quantitative comparison of two algorithms which have been tested at a fixed threshold in the same database. Here, traditional phase congruency has been modified to incorporate a dynamic estimate of muscle activity present in the input scalp EEG signal. The proposed algorithm achieves 50% data reduction whilst detecting more than 80% of interictal spikes. This represents a significant improvement over the state-of-the-art denoising method for phase congruency.

Toward Online Data Reduction for Portable Electroencephalography Systems in Epilepsy

Portable EEG units are key tools in epilepsy diagnosis. Current systems could be made physically smaller and longer lasting by the inclusion of online data reduction methods to reduce the power required for storage or transmission of the EEG data. This paper presents a real-time data reduction algorithm based upon the discontinuous recording of the EEG: noninteresting background sections of EEG are discarded online, with only potentially diagnostically interesting sections being saved. MATLAB simulations of the algorithm on an EEG dataset containing 982 expert marked events in 4 days of data show that 90% of events can be correctly recorded while achieving a 50% data reduction. The described algorithm is formulated to have a direct, low power, hardware implementation and similar data reduction strategies could be employed in a range of body-area-network-type applications.

A microprocessor based system for on-line data reduction of ECG signal and arrhythmia detection

A microprocessor based system for on-line data reduction of ECG signal and arrhythmia detection

HD 203608, a quiet asteroseismic target in the old galactic disk

Context. We conducted a 5-night observing run with the spectrometer harps at the ESO 3.6-m telescope in August 2006, to continue exploring the asteroseismic properties of F-type stars. In fact, Doppler observations of F-type on the main sequence are demanding and remain currently limited to a single case (HD 49933). Comparison with photometric results obtained with the CoRoT space mission (Convection, Rotation and planetary Transits) on similar stars will be possible with an enhanced set of observations. Aims. We selected the 4th magnitude F8V star HD 203608 to investigate the oscillating properties of a low-metallicity star of the old galactic disk. Methods. We reduced the spectra with the on-line data reduction software provided by the instrument. We developed a new statistical approach for extracting the significant peaks in the Fourier domain. Results. The oscillation spectrum shows a significant excess power in the frequency range [1.5, 3.0 mHz]. It exhibits a large spacing of about 120.4 μHz at 2.5 mHz. Variations of the large spacing with frequency are clearly identified, which require an adapted asymptotic development. The modes identification is based on the unambiguous signature of 15 modes with � = 0 and 1. Conclusions. These observations show the potential diagnostic of asteroseismic constraints. Including them in the stellar modeling significantly enhances the precision on the physical parameters of HD 203608, resulting in a much more precise position in the HR diagram. The age of the star is now determined in the range 7.25 ± 0.07 Gyr.

A VME-Based Readout System for the CMS Preshower Sub-Detector

The CMS preshower is a fine grain detector that comprises 4288 silicon sensors, each containing 32 strips. The raw data are transferred from the detector to the counting room via 1208 optical fibres. Each fibre carries a 600-byte data packet per event. The maximum average level-1 trigger rate of 100 kHz results in a total data flow of ~72 GB/s from the preshower. For the readout of the preshower, 56 links to the CMS DAQ have been reserved, each having a bandwidth of 200 MB/s (2 kB/event). The total available downstream bandwidth of GB/s necessitates a reduction in the data volume by a factor of at least 7. A modular VME-based system is currently under development. The main objective of each VME board in this system is to acquire on-detector data from at least 22 optical links, perform on-line data reduction and pass the concentrated data to the CMS DAQ. The principle modules that the system is based on are being developed in collaboration with the TOTEM experiment.

Implementation of on-line data reduction algorithms in the CMS Endcap Preshower Data Concentrator Cards

The CMS Endcap Preshower (ES) sub-detector comprises 4288 silicon sensors, each containing 32 strips. The data are transferred from the detector to the counting room via 1208 optical fibres running at 800Mbps. Each fibre carries data from two, three or four sensors. For the readout of the Preshower, a VME-based system, the Endcap Preshower Data Concentrator Card (ES-DCC), is currently under development. The main objective of each readout board is to acquire on-detector data from up to 36 optical links, perform on-line data reduction via zero suppression and pass the concentrated data to the CMS event builder. This document presents the conceptual design of the Reduction Algorithms as well as their implementation in the ES-DCC FPGAs. These algorithms, as implemented in the ES-DCC, result in a data-reduction factor of 20.

Probing the atmosphere of the bulge G5III star OGLE-2002-BUL-069 by analysis of microlensed Hα line

We discuss high-resolution, time-resolved spectra of the caustic exit of the binary microlensing event OGLE 2002-BLG-069 obtained with UVES on the VLT. The source star is a G5III giant in the Galactic Bulge. During such events, the source star is highly magnified, and a strong differential magnification around the caustic resolves its surface. Using an appropriate model stellar atmosphere generated by the PHOENIX v2.6 code we obtain a model light curve for the caustic exit and compare it with a dense set of photometric observations obtained by the PLANET microlensing follow up network. We further compare predicted variations in the equivalent width with those measured from our spectra. While the model and observations agree in the gross features, there are discrepancies suggesting shortcomings in the model, particularly for the line core, where we have detected amplified emission from the stellar chromosphere after the source star's trailing limb exited the caustic. This achievement became possible by the provision of the very efficient OGLE-III Early Warning System, a network of small telescopes capable of nearly-continuous round-the-clock photometric monitoring, on-line data reduction, daily near-real-time modelling in order to predict caustic crossing parameters, and a fast and efficient response of a 8 m class telescope to a “Target-of-Opportunity” observation request.

An extensible probe architecture for network protocol performance measurement

AbstractThis paper describes the architecture, implementation, and application of Windmill, a passive network protocol performance measurement tool. Windmill enables experimenters to measure a broad range of protocol performance metrics both by reconstructing application‐level network protocols and by exposing the underlying protocol layers' events. Windmill is split into three functional components: a dynamically compiled Windmill Protocol Filter (WPF), a set of abstract protocol modules, and an extensible experiment engine. To demonstrate Windmill's utility, we present the results from several experiments. The first set of experiments validates a possible cause for the correlation between Internet routing instability and network bandwidth usage. The second set of experiments highlights Windmill's ability to act as a driver for a complementary active Internet measurement infrastructure, its ability to perform online data reduction, and the non‐intrusive measurement of a closed system. Copyright © 2003 John Wiley & Sons, Ltd.

Concept and realization of a fully configurable and programmable data-acquisition system for the neutron scattering instruments at SINQ

We present the basic concept and the realization of our fully configurable data-acquisition hardware for the neutron scattering instruments at SINQ. This system allows collection of the different data entities and event-related signals generated by the various detector units. It offers a variety of synchronization options, including a time-measuring mode for time-of-flight determinations. Based on configurable logic (FPGA, CPLD), event rates up to the MHz range can be processed and transmitted to a programmable online data-reduction system (Histogram Memory). It is implemented on a commercially available VME Power PC module running a real-time operating system (VxWorks).

Molecular many-body dissociation: Data reduction strategies in translational spectroscopy

Advanced time- and position-sensitive multi-hit detectors allow to study molecular breakup processes into two, three, and more massive fragments by translational spectroscopy. We discuss the feasibility to perform kinematically complete final state analysis of complex molecular dissociation processes using such detectors. We have developed new algorithms to determine - for an arbitrary number of fragments - the fragment momentum vectors in the center-of-mass frame from the measured positions and arrival time differences. These algorithms can easily be implemented to perform online data reduction in coincidence experiments. We have tested the new data reduction strategies in an experimental study and in Monte-Carlo simulations of realistic experimental conditions. We show that the new algorithms can discriminate between two-, three-, and four-body decay of a four-atomic molecule and can uniquely determine the momentum vectors of all fragments. For two-body decay, we find that the accuracy of the new algorithm is superior to the frequently used approximate formula introduced by DeBruijn and Los. We demonstrate this improvement in the evaluation of experimental data for the decay of laser-excited triatomic hydrogen H3 3s (N=1,K=0) into H + H2(v,J) fragment pairs.

Potential Pitfalls in Screening Programs for Congenital Hypothyroidism

After completing this article, readers should be able to: 1. Delineate situations in which blood specimens for screening may be overlooked. 2. Describe the patterns of thyroid-stimulating hormone and thyroxine concentrations in very low-birthweight infants and the implications of these patterns for thyroid screening programs. For those of us involved in newborn screening, there is nothing more devastating than learning that the program did not detect an infant who has congenital hypothyroidism. After a moment of disbelief, we ask, “How did this happen and what should or could have been done to prevent such tragedy?” Moreover, in the typical scenario the misfortune frequently is compounded by failure of the clinician to make the clinical diagnosis in a timely fashion. Although these events are rare (probably less than one birth in 1 million), they should not be taken lightly. For the pediatrician, knowing where potential pitfalls lie might spare some future family from the needless anguish of a missed diagnosis. Slightly more than one quarter of a century ago a report emanating from Canada described a procedure for the measurement of thyroxine (T4) in dried blood on filter paper, opening the way for early detection and treatment of infants who have congenital hypothyroidism. Within a relatively short period of time, newborn screening programs for congenital hypothyroidism emerged in most of the industrialized nations, thereby relegating a major scourge of society to the status of a medical curiosity. At the outset, most screening programs were relatively primitive, lacking sophisticated data management systems and beset with technical and logistical problems. However, the manufacture of reliable assay materials and the introduction of automation coupled with online data reduction eventually improved these programs. Such improvements, together with growing experience in interpretating test results, overcame many of the drawbacks associated with early screening programs. Although most (but not …

Enhanced production of L-(+)-lactic acid in chemostat by Lactobacillus casei DSM 20011 using ion-exchange resins and cross-flow filtration in a fully automated pilot plant controlled via NIR

Due to the lack of suitable in-process sensors, on-line monitoring of fermentation processes is restricted almost exclusively to the measurement of physical parameters only indirectly related to key process variables, i.e., substrate, product, and biomass concentration. This obstacle can be overcome by near infrared (NIR) spectroscopy, which allows not only real-time process monitoring, but also automated process control, provided that NIR-generated information is fed to a suitable computerized bioreactor control system. Once the relevant calibrations have been obtained, substrate, biomass and product concentration can be evaluated on-line and used by the bioreactor control system to manage the fermentation. In this work, an NIR-based control system allowed the full automation of a small-scale pilot plant for lactic acid production and provided an excellent tool for process optimization. The growth-inhibiting effect of lactic acid present in the culture broth is enhanced when the growth-limiting substrate, glucose, is also present at relatively high concentrations. Both combined factors can result in a severe reduction of the performance of the lactate production process. A dedicated software enabling on-line NIR data acquisition and reduction, and automated process management through feed addition, culture removal and/or product recovery by microfiltration was developed in order to allow the implementation of continuous fermentation processes with recycling of culture medium and cell recycling. Both operation modes were tested at different dilution rates and the respective cultivation parameters observed were compared with those obtained in a conventional continuous fermentation. Steady states were obtained in both modes with high performance on lactate production. The highest lactate volumetric productivity, 138 g L−1 h−1, was obtained in continuous fermentation with cell recycling. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 67: 147–156, 2000.

Enhanced production of L-(+)-lactic acid in chemostat byLactobacillus casei DSM 20011 using ion-exchange resins and cross-flow filtration in a fully automated pilot plant controlled via NIR

Due to the lack of suitable in-process sensors, on-line monitoring of fermentation processes is restricted almost exclusively to the measurement of physical parameters only indirectly related to key process variables, i.e., substrate, product, and biomass concentration. This obstacle can be overcome by near infrared (NIR) spectroscopy, which allows not only real-time process monitoring, but also automated process control, provided that NIR-generated information is fed to a suitable computerized bioreactor control system. Once the relevant calibrations have been obtained, substrate, biomass and product concentration can be evaluated on-line and used by the bioreactor control system to manage the fermentation. In this work, an NIR-based control system allowed the full automation of a small-scale pilot plant for lactic acid production and provided an excellent tool for process optimization. The growth-inhibiting effect of lactic acid present in the culture broth is enhanced when the growth-limiting substrate, glucose, is also present at relatively high concentrations. Both combined factors can result in a severe reduction of the performance of the lactate production process. A dedicated software enabling on-line NIR data acquisition and reduction, and automated process management through feed addition, culture removal and/or product recovery by microfiltration was developed in order to allow the implementation of continuous fermentation processes with recycling of culture medium and cell recycling. Both operation modes were tested at different dilution rates and the respective cultivation parameters observed were compared with those obtained in a conventional continuous fermentation. Steady states were obtained in both modes with high performance on lactate production. The highest lactate volumetric productivity, 138 g L(-1) h(-1), was obtained in continuous fermentation with cell recycling.

Fast detector readout for the HADES-RICH

The readout electronics for the HADES RICH uses new concepts for the data transport and a multilevel trigger scheme for online data reduction. We have developed two types of modules for the readout of the RICH detector that is used for lepton identification in the HADES spectrometer. The first one is a mixed analog and digital frontend module that converts the charge signals from the detector to digital data words. The second module controls the digital readout of the frontend modules and the transport of the event data to a VMEbus memory.

EDS and WDS Automation: Past Development and Future Technology

Abstract Early Development Automation of electron probe analysis began to flourish in the early 1970s spurred on by advances in computer technology and the availability of operating systems and programming languages that the individual researcher could afford to dedicate to a single instrument. By the end of the decade, most researchers and vendors in the microanalysis field had adopted the PDP-11 minicomputer, and languages such as FOCAL, FORTRAN and BASIC that ran on these computers. A good summary of these early efforts was given by Hatfield. The first use of the energy dispersive detector on the electron probe in 1968 added the need to control the acquisition, display and processing of EDS spectra. As a result, the 70’s were also a time when much attention was focussed on development of software for on-line data reduction and analysis. These efforts produced a suite of programs to provide matrix corrections and spectral processing, and automation of WDS data collection. The culmination of these development efforts was first reported in 1977 with the analysis of a lunar whitlockite mineral by simultaneous EDS/WDS measurement. This analysis determined the concentration of 23 elements, 8 by EDS and took a total of 37 minutes for data collection and analysis. In this paper, the authors noted the complementary use of the EDS and WDS (WDS for trace elements and severe peak overlaps, EDS for other elements and rapid qualitative analysis) in their automated instrument, a convention that remains common on the electron probe even today. Toward the end of the decade the analytical accuracy and precision achieved by automated analysis of bulk samples approached the limits of the instrumentation, with the exception of analysis of light element concentrations. Two Decades of Improvements The explosive growth in digital electronics and microprocessors for data processing and control functions during the 80’s was rapidly applied to electron probe automation. Second and third generation automation systems included direct control of many microscope functions, beam position and imaging conditions. Motor positioning was more precise and far faster. As a result, the data collection and analysis of 23 elements reported in 1977 could be accomplished at least three times faster on a modern instrument.

An extensible probe architecture for network protocol performance measurement

This paper describes the architecture and implementation of Windmill, a passive network protocol performance measurement tool. Windmill enables experimenters to measure a broad range of protocol performance metrics by both reconstructing application-level network protocols and exposing the underlying protocol layers' events. Windmill is split into three functional components: a dynamically compiled Windmill Protocol Filter (WPF), a set of abstract protocol modules, and an extensible experiment engine. To demonstrate Windmill's utility, the results from several experiments are presented. The first set of experiments suggests a possible cause for the correlation between Internet routing instability and network utilization. The second set of experiments highlights: Windmill's ability to act as a driver for a complementary active Internet measurement apparatus, its ability to perform online data reduction, and the non-intrusive measurement of a closed system.