Detection Of Single Events Research Articles

Sleep spindle maturity promotes slow oscillation-spindle coupling across child and adolescent development.

The synchronization of canonical fast sleep spindle activity (12.5-16 Hz, adult-like) precisely during the slow oscillation (0.5-1 Hz) up peak is considered an essential feature of adult non-rapid eye movement sleep. However, there is little knowledge on how this well-known coalescence between slow oscillations and sleep spindles develops. Leveraging individualized detection of single events, we first provide a detailed cross-sectional characterization of age-specific patterns of slow and fast sleep spindles, slow oscillations, and their coupling in children and adolescents aged 5-6, 8-11, and 14-18 years, and an adult sample of 20- to 26-year-olds. Critically, based on this, we then investigated how spindle and slow oscillation maturity substantiate age-related differences in their precise orchestration. While the predominant type of fast spindles was development-specific in that it was still nested in a frequency range below the canonical fast spindle range for the majority of children, the well-known slow oscillation-spindle coupling pattern was evident for sleep spindles in the adult-like canonical fast spindle range in all four age groups-but notably less precise in children. To corroborate these findings, we linked personalized measures of fast spindle maturity, which indicate the similarity between the prevailing development-specific and adult-like canonical fast spindles, and slow oscillation maturity, which reflects the extent to which slow oscillations show frontal dominance, with individual slow oscillation-spindle coupling patterns. Importantly, we found that fast spindle maturity was uniquely associated with enhanced slow oscillation-spindle coupling strength and temporal precision across the four age groups. Taken together, our results suggest that the increasing ability to generate adult-like canonical fast sleep spindles actuates precise slow oscillation-spindle coupling patterns from childhood through adolescence and into young adulthood.

Noninvasive Detection of Hippocampal Epileptiform Activity on Scalp Electroencephalogram

The hippocampus is a highly epileptogenic brain region, yet over 90% of hippocampal epileptiform activity (HEA) cannot be identified on scalp electroencephalogram (EEG) by human experts. Currently, detection of HEA requires intracranial electrodes, which limits our understanding of the role of HEA in brain diseases. To develop and validate a machine learning algorithm that accurately detects HEA from a standard scalp EEG, without the need for intracranial electrodes. In this diagnostic study, conducted from 2008 to 2021, EEG data were used from patients with temporal lobe epilepsy (TLE) and healthy controls (HCs) to train and validate a deep neural network, HEAnet, to detect HEA on scalp EEG. Participants were evaluated at tertiary-level epilepsy centers at 2 academic hospitals: Massachusetts General Hospital (MGH) or Brigham and Women's Hospital (BWH). Included in the study were patients aged 12 to 78 years with a clinical diagnosis of TLE and HCs without epilepsy. Patients with TLE and HCs with a history of intracranial surgery were excluded from the study. Simultaneous intracranial EEG and/or scalp EEG. Performance was assessed using cross-validated areas under the receiver operating characteristic curve (AUC ROC) and precision-recall curve (AUC PR) and additional clinically relevant metrics. HEAnet was trained and validated using data sets that were derived from a convenience sample of 141 eligible participants (97 with TLE and 44 HCs without epilepsy) whose retrospective EEG data were readily available. Data set 1 included the simultaneous scalp EEG and intracranial electrode recordings of 51 patients with TLE (mean [SD] age, 40.7 [15.9] years; 30 men [59%]) at MGH. An automatically generated training data set with 972 095 positive HEA examples was created, in addition to a held-out expert-annotated testing data set with 22 762 positive HEA examples. HEAnet's performance was validated on 2 independent scalp EEG data sets: (1) data set 2 (at MGH; 24 patients with TLE and 20 HCs; mean [SD] age, 42.3 [16.2] years; 17 men [39%]) and (2) data set 3 (at BWH; 22 patients with TLE and 24 HCs; mean [SD] age, 43.0 [14.4] years; 20 men [43%]). For single-event detection of HEA on data set 1, HEAnet achieved a mean (SD) AUC ROC of 0.89 (0.01) and a mean (SD) AUC PR of 0.39 (0.03). On external validation with data sets 2 and 3, HEAnet accurately distinguished TLE from HC (AUC ROC of 0.88 and 0.95, respectively) and predicted epilepsy lateralization with 100% and 92% accuracy, respectively. HEAnet tracked dynamic changes in HEA in response to seizure medication adjustments and performed comparably with human experts in diagnosing TLE from 1-hour scalp EEG recordings, diagnosing TLE in several individuals that experts missed. Without reducing specificity, addition of HEAnet to human expert EEG review increased sensitivity for diagnosing TLE in humans from 50% to 58% to 63% to 67%. Results of this diagnostic study suggest that HEAnet provides a novel, noninvasive, quantitative, and clinically relevant biomarker of hippocampal hyperexcitability in humans.

An Adaptive Two-Stage Load Event Detection Method for Nonintrusive Load Monitoring

Load event detection is fundamental to event-based nonintrusive load monitoring (NILM) solution. It is directly related to whether the transient and steady-state signatures of appliances can be accurately extracted. In the real world, the load composition is random and complicated, the power consumption patterns of appliances are diverse, and multiple events may occur simultaneously or near each other, all these make it difficult for any one single event detection method to achieve satisfactory robustness. In coping with this, an adaptive two-stage event detection method is proposed in this article. First, an adaptive detection threshold whose value can be adjusted adaptively according to the load fluctuations is adopted, thus improving the ability to detect events of different amplitudes. Then, considering the different event geometric features, an improved edge detection method and a window-based detection method combining moving average with moving t-test are proposed for step-like events and long-transient events, respectively, and they are executed consecutively to achieve the effective capture of the complete transient process of appliances. Furthermore, an event separation step is taken to locate and separate the near-simultaneous events which often appear in low-frequency data. Specific event detection performance evaluation metrics are also designed. Comparison test results on private and public datasets show that the proposed method achieves high detection accuracy for different events of various appliances and maintains strong robustness in different operation scenarios.

An open-source, end-to-end workflow for multidimensional photoemission spectroscopy

Characterization of the electronic band structure of solid state materials is routinely performed using photoemission spectroscopy. Recent advancements in short-wavelength light sources and electron detectors give rise to multidimensional photoemission spectroscopy, allowing parallel measurements of the electron spectral function simultaneously in energy, two momentum components and additional physical parameters with single-event detection capability. Efficient processing of the photoelectron event streams at a rate of up to tens of megabytes per second will enable rapid band mapping for materials characterization. We describe an open-source workflow that allows user interaction with billion-count single-electron events in photoemission band mapping experiments, compatible with beamlines at 3rd and 4rd generation light sources and table-top laser-based setups. The workflow offers an end-to-end recipe from distributed operations on single-event data to structured formats for downstream scientific tasks and storage to materials science database integration. Both the workflow and processed data can be archived for reuse, providing the infrastructure for documenting the provenance and lineage of photoemission data for future high-throughput experiments.

Determination of X-ray tubes radiation beam characteristics with semiconductor pixel detectors

X-ray tubes belong among the most important sources of ionizing radiation and are used in various applications and methods, i.e. investigation of materials, diagnostics in medicine, irradiation, etc. For such applications, the exact properties of X-ray sources or their X-ray beams need to be known, as well as when Monte Carlo simulations of experimental setups are considered with the aim of optimization or calibration of X-ray systems. These properties include X-ray spectra, beam profiles, divergence and homogeneity of beams. Properties of low power X-ray tubes with the maximum voltage up to 50 kV were investigated in this study. These devices included a small laboratory X-ray tube with collimated X-ray beam and a microfocus X-ray tube with polycapillary focusing optics. Beam shape features were reconstructed using a silicon pixel detector. The pixel detector was inserted into X-ray beams at different distances from X-ray sources. Beam 2D profiles were obtained and since the pixel detector worked in a single event detection mode, approximate energy of individual photons could be measured as well as their position. In this way, detailed information about the beam properties was obtained. • X-ray beam parameters are mapped by a pixel detector. • The beam shape and energy distribution of the emitted photons are assessed. • The size of the irradiated point and the quality of the collimators are determined.

An Automated Method for Characterization of Evoked Single-Trial Local Field Potentials Recorded from Rat Barrel Cortex Under Mechanical Whisker Stimulation

Rodents explore their surroundings through whisking by localizing objects and detecting textures very precisely. During such tactile exploration, whisker deflection is first mechanically transduced by receptors and then information encoded throughout the somatosensory pathway ending in the somatosensory ‘barrel’ cortex. In the barrel cortex, tactile information from a single whisker is segregated and processed in a cortical column corresponding to the deflected whisker. Local Field Potentials (LFPs) generated by whisker deflection in the barrel cortex present typical signatures in terms of shape and amplitude that are related to the activation of the local neuronal populations. Therefore, rigorous analysis of such responses may reveal important features about the function of underlying neuronal microcircuits. In this context, software methods for characterizing single-trial LFPs are needed that are also suitable for online extraction of LFP features and for brain–machine interfacing applications. In this work, we present an automated and efficient method to analyze evoked LFP responses in the rat barrel cortex through automatic removal of stimulation artifacts, detection of single events and characterization of their relevant parameters. Evoked single-trial LFPs recorded under two different anesthetics are examined to demonstrate the feasibility, accuracy and applicability of the method.

Leveraging Strategic Detection Techniques for Smart Home Pricing Cyberattacks

In this work, the vulnerability of the electricity pricing model in the smart home system is assessed. Two closely related pricing cyberattacks which manipulate the guideline electricity prices received at smart meters are considered and they aim at reducing the expense of the cyberattacker and increasing the peak energy usage in the local community. A single event detection technique which uses support vector regression and impact difference for detecting anomaly pricing is proposed. The detection capability of such a technique is still limited since it does not model the long term impact of pricing cyberattacks. This motivates us to develop a partially observable Markov decision process based detection algorithm, which has the ingredients such as reward expectation and policy transfer graph to account for the cumulative impact and the potential future impact due to pricing cyberattacks. Our simulation results demonstrate that the pricing cyberattack can reduce the cyberattacker's bill by 34.3 percent at cost of the increase of others’ bill by 7.9 percent, and increase the peak to average ratio (PAR) by 35.7 percent. Furthermore, the proposed long term detection technique has the detection accuracy of more than 97 percent with significant reduction in PAR and bill compared to repeatedly using the single event detection technique.

Sample Preparation and Data Acquisition for μs-ALEX.

This protocol describes the preparation of samples and data acquisition for microsecond-alternating laser excitation. Sample preparation requires a dilution that ensures the detection of single events.

An Implicit Correlation Method for Cross-Correlation Sampling, with MCNPX-PoliMi Validation

Monte Carlo particle transport codes used to model detector responses are traditionally run in analog mode. However, analog simulations of cross-correlation measurements are extremely time-consuming because the probability of coincident detection is small, approximately equal to the product of the probabilities of a single detection in each detector. The new implicit correlation method described here increases the number of correlated event scores, thereby reducing variance and required computation times. The cost of the implicit correlation method is comparable to the cost of simulating single-event detection for the lowest absolute detector efficiency in the problem. The new method is especially useful in the nuclear nonproliferation and safeguards fields for simulating correlation measurements of shielded special nuclear material.The new method was implemented in MCNPX-PoliMi for neutron-neutron cross-correlations with a 252Cf spontaneous fission source measured by 14 detectors at various angles. The method demonstrated good agreement with analog simulation and reference measurement results. Small differences between nonanalog and analog cross-correlation distributions are attributed to discretization errors that are often not present in practical applications. Improvement in the figure of merit was greater than a factor of 100 in all tested cases.

Droplet digital PCR versus multiplex real-time PCR method for the detection and quantification of DNA from the four transgenic soy traits MON87769, MON87708, MON87705 and FG72, and lectin

New genetically modified (gm) soy crops are going to be released for human consumption. Therefore, analytical skills have to be developed towards an efficient detection and determination of GMO content in feed and food. Existing approaches to screen gm plants do not detect new gm soy traits in many cases. Therefore, a multiplex quantitative real-time PCR system was developed and characterized for the four new transgenic soy traits MON87769, MON87708, MON87705 and FG72 to avoid time- and cost-consuming application of single event detection. It showed amplification efficiency, correlation and limit of quantification similar to the single PCR systems applied. The droplet digital PCR showed increased specificity. In parallel, we developed four duplex droplet digital PCR systems and compared the results from both methods. This showed that both approaches are fit for routine diagnostics. Real-time PCR may be more suited for screening as it is very cost-efficient. Digital PCR may be more suitable for quantitative analysis as it exhibited a measurement uncertainty of only 17 % or below for a single reaction.

Wavelet packet transform for detection of single events in acoustic emission signals

Acoustic emission signals in tribology can be used for monitoring the state of bodies in contact and relative motion. The recorded signal includes information which can be associated with different events, such as the formation and propagation of cracks, appearance of scratches and so on. One of the major challenges in analyzing these acoustic emission signals is to identify parts of the signal which belong to such an event and discern it from noise. In this contribution, a wavelet packet decomposition within the framework of multiresolution analysis theory is considered to analyze acoustic emission signals to investigate the failure of tribological systems. By applying the wavelet packet transform a method for the extraction of single events in rail contact fatigue test is proposed. The extraction of such events at several stages of the test permits a classification and the analysis of the evolution of cracks in the rail.

Underwater Neutrino Detection in the Mediterranean Sea: From Present to Future

The observation of high-energy extraterrestrial neutrinos is one of the most promising future options to increase our knowledge of non-thermal processes in the universe. Neutrinos are e.g. unavoidably produced in environments where high-energy hadrons collide; in particular this is almost certainly true at astrophysical accelerators of cosmic rays, which thus could be identified unambiguously by sky observations in “neutrino light”. To establish neutrino astronomy beyond the detection of single events, neutrino telescopes of km 3 scale are needed. In order to obtain full sky coverage, a corresponding detector in the Mediterranean Sea is required to complement the IceCube experiment currently under construction at the South Pole. The groups pursuing the current neutrino telescope projects in the Mediterranean Sea, ANTARES, NEMO and NESTOR, have joined to prepare this future installation in a 3-year, EU-funded Design Study named KM3NeT (in the following, this name will also denote the future detector). This report highlights some scientific key questions, addresses the status of current projects and outlines the path towards the realization of KM3NeT.

Multichannel wearable system dedicated for simultaneous electroencephalography∕near-infrared spectroscopy real-time data acquisitions

Functional neuroimaging is becoming a valuable tool in cognitive research and clinical applications. The clinical context brings specific constraints that include the requirement of a high channel count to cover the whole head, high sensitivity for single event detection, and portability for long-term bedside monitoring. For epilepsy and stroke monitoring, the combination of electroencephalography (EEG) and functional near-infrared spectroscopy (NIRS) is expected to provide useful clinical information, and efforts have been deployed to create prototypes able to simultaneously acquire both measurement modalities. However, to the best of our knowledge, existing systems lack portability, NIRS sensitivity, or have low channel count. We present a battery-powered, portable system with potentially up to 32 EEG channels, 32 NIRS light sources, and 32 detectors. Avalanche photodiodes allow for high NIRS sensitivity and the autonomy of the system is over 24 h. A reduced channel count prototype with 8 EEG channels, 8 sources, and 8 detectors was tested on phantoms. Further validation was done on five healthy adults using a visual stimulation protocol to detect local hemodynamic changes and visually evoked potentials. Results show good concordance with literature regarding functional activations and suggest sufficient performance for clinical use, provided some minor adjustments were made.

Printed Write Once and Read Many Sensor Memories in Smart Packaging Applications

A horizontal printed Write-Once-Read-Many (WORM) resistive memory has been developed for use in wireless sensor tags targeting single-event detection in smart packaging applications. The WORM memory can be programmed using a 1.5-V printed battery. An alternative programming method is to use chemical sintering which allows the development of exposure-time triggered single event tags that can be accessed wirelessly. The new WORM memory has very low losses in the ON-state which allows direct integration into antenna structures. A sensor tag that utilizes the WORM memory functionality and the well established Electronic Article Surveillance (EAS) communication standard has been outlined. Both active and fully passive sensor tag solutions have been proposed. The role of printed electronics in smart packaging applications has been reviewed and discussed. Important enabling factors for the future development have been highlighted, such as the need for hierarchical design and test tools, better printed interconnect technologies as well as better components that allow communication with existing information and communication technology (ICT) standards. This is illustrated and underlined by the presented smart packaging concept demonstrators.

Single-Event Correlation Analysis of Quantum Key Distribution with Single-Photon Sources

Multiple photons exist that allow efficient eavesdropping strategies that threaten the security of quantum key distribution. In this paper, we theoretically discuss the photon correlations between authorized partners in the case of practical single-photon sources including a multiple-photon background. To investigate the feasibility of intercept-resend attacks, the cross correlations and the maximum intercept-resend ratio caused by the background signal are determined using single-event correlation analysis based on single-event detection.

KM3NeT, a new generation neutrino telescope

To establish neutrino astronomy beyond the detection of single events, telescopes of cubic kilometer scale are needed. The IceCube neutrino telescope currently being built at the South Pole will be the first telescope with a detection volume of this size. In order to obtain full sky coverage, the construction of a corresponding telescope in the Northern hemisphere is being prepared. Since February 2006, the ANTARES, NEMO and NESTOR neutrino telescope projects have joined forces in the KM3NeT Design Study, supported by the European Commission in the FP6 framework, with the aim of compiling a technical design report for the construction of a neutrino telescope in the Mediterranean Sea with a detection volume of at least a cubic kilometer. In addition the KM3NeT facility will house a long-term cabled observatory for marine sciences. This report will focus on the status of the Design Study and highlight some of the concepts being studied.

KM3NeT: Towards a km3 Mediterranean neutrino telescope

The observation of high-energy extraterrestrial neutrinos is one of the most promising future options to increase our knowledge on non-thermal processes in the universe. Neutrinos are e.g. unavoidably produced in environments where high-energy hadrons collide; in particular, this almost certainly must be true in the astrophysical accelerators of cosmic rays, which thus could be identified unambiguously by sky observations in “neutrino light”. To establish neutrino astronomy beyond the detection of single events, neutrino telescopes of km3 scale are needed. In order to obtain full sky coverage, a corresponding detector in the Mediterranean Sea is required to complement the IceCube experiment currently under construction at the South Pole. The groups pursuing the current neutrino telescope projects in the Mediterranean Sea, ANTARES, NEMO and NESTOR, have joined to prepare this future installation in a 3-year, EU-funded design study named KM3NeT (in the following, this name will also denote the future detector). This report will highlight some of the physics issues to be addressed with KM3NeT and will outline the path towards its realisation, with a focus on the upcoming design study.

Development of hybrid low-pressure MSGC neutron detectors

For very high rate and resolution time-resolved experiments at next generation pulsed spallation neutron sources like ESS large-area hybrid low-pressure micro-strip gas chamber detectors are being developed. Due to their thin composite converter foil and exponential gas multiplication commencing at the converter surfaces the detectors are free of parallax, and according to detailed modeling the very high transverse and longitudinal localization accuracies in the conversion and gas multiplication processes allow position and time resolutions of ∼100 μm and <10 ns FWHM for thermal neutrons, respectively, the latter limited by the transit time through the converter. In the European R&D project TECHNI for this detector an advanced delay line readout technology with multi-event readout was developed as an economical solution for the majority of applications, which, however, limits the position resolution and rate capability to <0.3 mm and 1–2 Mcps, respectively. Therefore, in the successor project DETNI a dedicated ASIC family is being developed for achieving position resolutions of ∼100 μm FWHM and counting rates of ∼10 8 cps. This will open up novel applications based on time-of-flight (TOF) and single-event detection with very high dynamic range, replacing integrating CCD and image plate detectors, e.g. in radiography/tomography, TOF Laue diffraction, single crystal diffraction and focusing low- Q SANS. In this conference report new results concerning the technical realization of this detector system are reported in conjunction with a brief summary of the detector principle and with reference to earlier results.

Calculation and measurement of the time-of-flight spread in a hemispherical electron energy analyzer

We have determined the transit time distribution of electrons passing a high resolution hemispherical energy analyzer. Comparison of our measured results with analytical expressions reveals that differing transit times between electrons of equal kinetic energy mainly build up on the Kepler-type orbits on which the electrons travel through the hemispheres. To facilitate the measurements, we have installed a position sensitive electron detector capable of single event detection into our spectrometer. This device is based on a delay-line anode. We briefly report on the energy resolution achieved in comparison with a slower readout system via a fluorescent screen. The transit time distribution is important in coincidence experiments, where electrons detected in the hemispherical analyzer are to be related to events in other detectors. We discuss the feasibility of electron–electron coincidence experiments using a hemispherical detector plus a time-of-flight drift tube for energy discrimination of an electron pair.

Resolving power enhancement of a discrete detector (array) by single event detection

Experiments have been performed to demonstrate the high resolving power of a discrete detector array that can be achieved by measuring and processing single ion events (speckle mode). Measurement of the spectrum of Kr + using a miniature mass spectrometer developed at the jet propulsion laboratory equipped with a focal plane detector developed at Aberystwyth show a large resolving power enhancement in the speckle mode and good agreement with tabulated peak centroids and isotope abundances. The mode of operation of the instrument is under software control and is instantly variable. This clearly demonstrates the versatility and high performance of the miniaturised system.