Time Analysis Method Research Articles

Intermittency-induced criticality in the lower ionosphere prior to the 2016 Kumamoto earthquakes as embedded in the VLF propagation data observed at multiple stations

A network of 8 VLF/LF receivers has recently been established across Japan, receiving subionospheric signals from different transmitters located both in the same and other countries. The primary purpose of this network is to study disturbances in the VLF/LF propagation through the lower ionosphere in possible relation to earthquake (EQ) preparation processes. Ionospheric perturbations of possible seismic origin have long been investigated and considered very promising for short-term EQ prediction. The raw amplitude data on reception of the above-mentioned network, after being appropriately filtered, were analyzed by means of the method of critical fluctuations (MCF) in analogy to thermal critical systems. The MCF analysis of the VLF/LF propagation revealed that intermittency-induced criticality was reached in the lower ionosphere from ~1week to 3days prior to the catastrophic 2016 Kumamoto EQs. These fault-type EQs occurred within a two-day period (14 April: MW=6.2 and MW=6.0, 15 April: MW=7.0) at shallow depths (~10km) and very close epicenters, while the main event was as huge as the former 1995 Kobe EQ. MCF analysis results are compared to those by the conventional nighttime fluctuation method as well as to those by natural time analysis method obtained for the same dataset, and are found to exhibit remarkable consistency.

Time Analysis of Building Dynamic Response Under Seismic Action. Part 1: Theoretical Propositions

The first part of the article presents the main provisions of the analytical approach – the time analysis method (TAM) developed for the calculation of the elastic dynamic response of rod structures as discrete dissipative systems (DDS) and based on the investigation of the characteristic matrix quadratic equation. The assumptions adopted in the construction of the mathematical model of structural oscillations as well as the features of seismic forces’ calculating and recording based on the data of earthquake accelerograms are given. A system to resolve equations is given to determine the nodal (kinematic and force) response parameters as well as the stress-strain state (SSS) parameters of the system’s rods.

Time Analysis of Building Dynamic Response Under Seismic Action. Part 2: Example of Calculation

The second part of the article illustrates the use of the time analysis method (TAM) by the example of the calculation of a 3-storey building, the design dynamic model (DDM) of which is adopted in the form of a flat vertical cantilever rod with 3 horizontal degrees of freedom associated with floor and coverage levels. The parameters of natural oscillations (frequencies and modes) and the results of the calculation of the elastic forced oscillations of the building’s DDM – oscillograms of the reaction parameters on the time interval t ∈ [0; 131,25] sec. The obtained results are analyzed on the basis of the computed values of the discrepancy of the DDS motion equation and the comparison of the results calculated on the basis of the numerical approach (FEM) and the normative method set out in SP 14.13330.2014 “Construction in Seismic Regions”. The data of the analysis testify to the accuracy of the construction of the computational model as well as the high accuracy of the results obtained. In conclusion, it is revealed that the use of the TAM will improve the strength of buildings and structures subject to seismic influences when designing them.

Simulation and real time analysis of network protection tripping strategy based on behavior trees

The collaboration of multi intelligent electronic devices (IEDs) in a protection system can improve the both selectivity and real-time performance of the system. To verify the feasibility and real-time performance of a network trip strategy based on multi protection IEDs, a modeling and real time analysis method of the protection system based on behavior trees is proposed. The model of protection IED and circuit breaker in the network trip strategy is presented; the model of the delay behavior of the wide area network with normal topology is further more presented; using a network tripping strategy as example, the theory completion time of every behavior in the system has been calculated. The validity of our method was verified via three examples; this method can also complete the real-time analysis of isolated faulty components in a protection system under circumstances of line fault, circuit breaker failure, and protection component refuse movement.

Who becomes a grandparent – and when? Educational differences in the chances and timing of grandparenthood

Background: Despite recent advances, the demographic understanding of grandparenthood remains limited. Objective: Our study examines educational differences in the transition to grandparenthood. Comparing East and West Germany, we analyze educational differences in a) the chance of becoming a grandparent, and b) the timing of grandparenthood for both men and women. Methods: We used fertility data across three family generations (German Ageing Survey, N = 2,434 men and women born 1933‒1948) and methods of survival time analysis to study educational gradients in the transition to grandparenthood. Results: We found a strong educational gradient in the chances of grandparenthood among West German women: Lower-educated women’s chances of becoming a grandmother were similar to higher-educated women’s chances of becoming a mother. Conclusions: Our findings have implications for research on multi-generational social mobility and on the consequences of grandparenthood. Contribution: Our study is the first to analyze how the transition to grandparenthood is socially stratified.

Resilience-Aware Frequency Tuning for Neural-Network-Based Approximate Computing Chips

Unlike conventional ICs, approximate computing chips are less sensitive to hardware errors. This fascinating feature can be utilized to improve the performance of chip design and even change the timing closure procedure of digital circuit design flow. In this paper, we study the potential of resilience-aware circuit clocking scheme, and demonstrate the methodology with advanced neural network (NN)-based accelerator. We propose a novel timing analysis and frequency setting method for NN-based approximate computing circuits based on in-field NN retraining. With the proposed iterative retiming-and-retraining framework, NN-based accelerator can be retrained to operate safely at aggressive operating frequencies compared with the frequency decided purely by statistical timing analysis or Monto Carlo analysis. For nanometer process technology with increasing threats of timing errors induced by process variation, noises, and so on, our retiming-and-retraining method enables higher circuit operating frequency and enables dynamic precision/frequency adjustment for approximate computing circuits. We evaluate the methodology with both the neural and deep learning accelerators in experiments. The experimental results show that timing errors in neural circuits can be effectively tamed for different applications, so that the circuits can operate at higher clocking rates under the specified quality constraint or be dynamically scaled to work at a wide range of frequency states with only minor accuracy losses.

A dynamic time delay analysis approach for correlated process variables

Generally, dynamic characteristics of time delays between process correlated variables are major concerns in the process control community. However, traditional delay time analysis methods have limited ability to deal with dynamics of time delays. In response to this problem, this paper proposes a dynamic time delay analysis (DTA) based on the technology of time series data mining, aiming at effectively estimating transfer time delays between process correlated variables. Employing dynamic sliding windows, dynamic time delays can be estimated offline by calculating similarities between correlated variables. Subsequently, through an additional correlation analysis between the time delay and process variables, main variables influencing the time delay can be obtained. By providing relevant trend variables, an improved fuzzy interpolation prediction method is suggested to estimate the transfer time delay between process correlated variables online. In addition, a DTA dynamic directed time graph is created by combining dynamic transfer time delays of mutually dependent variables. Finally, performances of the DTA method are tested through a numerical study and a distillation column simulation.

RETRACTED ARTICLE: A novel system for automatic detection of K-complexes in sleep EEG

Sleep staging process is applied to diagnose sleep-related disorders by sleep experts through analyzing sleep signals such as electroencephalogram (EEG), electrooculogram and electromyogram of subjects and determining the stages in 30-s-length time parts of sleep named as epochs. Subjects enter several stages during the sleep, and N-REM2 is one of them which has also the highest duration among the other stages. Approximately half of the sleep consists of N-REM2. One of the important parameters in determining N-REM2 stage is K-complex (Kc). In this study, some time and frequency analysis methods were used to determine the locations of Kcs, automatically. These are singular value decomposition (SVD), variational mode decomposition and discrete wavelet transform. The performance of them in detecting Kcs was compared. Furthermore, systems with combinations of these methods were presented with logic AND operations. The EEG recordings of seven subjects were obtained from the Sleep Research Laboratory of Necmettin Erbakan University. A database with total 359 Kcs in 320 epochs was prepared from the recordings. According to the results, the highest average recognition rate was found as 92.29% for the SVD method. Thanks to this study, the sleep experts can find out whether there were Kcs in related epochs and also know their locations in these epochs, automatically. Also, it will help automatic sleep stage classification systems.

Dynamic response analysis of the equivalent water depth truncated point of the catenary mooring line

The real-time computer-controlled actuators are used to connect the truncated parts of moorings and risers in the active hybrid model testing system. This must be able to work in model-scale real time, based on feedback input from the floater motions. Thus, mooring line dynamics and damping effects are artificially simulated in real time, based on a computer-based model of the problem. In consideration of the nonlinear characteristics of the sea platform catenary mooring line, the equations of the mooring line motion are formulated by using the lumped-mass method and the dynamic response of several points on the mooring line is investigated by the time and frequency domain analysis method. The dynamic response of the representative point on the mooring line is analyzed under the condition of two different corresponding upper endpoint movements namely sine wave excitation and random wave excitation. The corresponding laws of the dynamic response between the equivalent water depth truncated points at different locations and the upper endpoint are obtained, which can provide technical support for further study of the active hybrid model test.

Dynamic Calculation of Nonlinear Oscillations of Flat Trusses Part 1: Mathematical Model of Nonlinear Structural Oscillations

The article deals with the application of the analytical method – the method of time analysis – to the problems of dynamic discrete dissipative systems, taking into account the physical and structural nonlinearity. Here are the equations of the mathematical model of nonlinear oscillations of discrete systems that allow representing the vector of dynamic restoring force as the algebraic sum of the linear and nonlinear components. This makes it possible to realize a diagram of a deformation piecewise linear form with consolidation and unloading. In this system of differential equations of motion at a certain time interval has the form of ODE with constant coefficients. This allows modeling of a common position to determine the dynamic response of the system for these types of non-linearity. Analytical expressions of jumps of the designed dynamic response parameters are also given during their transition to a new state in a nonlinear operation, showing that the value of the jump depends on the change in stiffness and damping matrices.

Field Prototype of the ENEA Neutron Active Interrogation Device for the Detection of Dirty Bombs

The Italian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA) Neutron Active Interrogation (NAI) device is a tool designed to improve CBRNE defense. It is designed to uncover radioactive and nuclear threats including those in the form of Improvised Explosive Devices (IEDs), the so-called “dirty bombs”. The NAI device, at its current development stage, allows to detect 6 g of 235U hidden in a package. It is easily transportable, light in weight, and with a real-time response. Its working principle is based on two stages: (1) an “active” stage in which neutrons are emitted by a neutron generator to interact with the item under inspection, and (2) a “passive” stage in which secondary neutrons are detected originating a signal that, once processed, allows recognition of the offence. In particular, a clear indication of the potential threat is obtained by a dedicated software based on the Differential Die-Away Time Analysis method.

Crust structure beneath Jilin Province and Liaoning Province in China based on seismic ambient noise tomography

We imaged the crust structure beneath Jilin Province and Liaoning Province in China with fundamental mode Rayleigh waves recorded by 60 broadband stations deployed in the region. Surface-wave empirical Green's functions were retrieved from cross-correlations of inter-station data and phase velocity dispersions were measured using a frequency–time analysis method. Dispersion measurements were then utilized to construct 2D phase velocity maps for periods between 5 and 35s. Subsequently, the phase-dispersion curves extracted from each cell of the 2D phase velocity maps were inverted to determine the 3D shear wave velocity structures of the crust. The phase velocity maps at different periods reflected the average velocity structures corresponding to different depth ranges. The maps in short periods, in particular, were in excellent agreement with known geological features of the surface. In addition to imaging shear wave velocity structures of the volcanoes, we show that obvious low-velocity anomalies imaged in the Changbaishan-Tianchi Volcano, the Longgang-Jinlongdingzi Volcano, and the system of the Dunmi Fault crossing the Jingbohu Volcano, all of which may be due to geothermal anomalies.

Effects of snow cover on ground thermal regime: A case study in Heilongjiang Province of China

The important effects of snow cover to ground thermal regime has received much attention of scholars during the past few decades. In the most of previous research, the effects were usually evaluated through the numerical models and many important results are found. However, less examples and insufficient data based on field measurements are available to show natural cases. In the present work, a typical case study in Mohe and Beijicun meteorological stations, which both are located in the most northern tip of China, is given to show the effects of snow cover on the ground thermal regime. The spatial (the ground profile) and time series analysis in the extremely snowy winter of 2012–2013 in Heilongjiang Province are also performed by contrast with those in the winter of 2011–2012 based on the measured data collected by 63 meteorological stations. Our results illustrate the positive (warmer) effect of snow cover on the ground temperature (GT) on the daily basis, the highest difference between GT and daily mean air temperature (DGAT) is as high as 32.35°C. Moreover, by the lag time analysis method it is found that the response time of GT from 0 cm to 20 cm ground depth to the alternate change of snow depth has 10 days lag, while at 40 cm depth the response of DGAT is not significant. This result is different from the previous research by modeling, in which the response depth of ground to the alteration of snow depth is far more than 40 cm.

A possible 55-d X-ray period of the ultraluminous accreting pulsar M82 X–2

We report a possible detection of a 55-day X-ray modulation for the ultraluminous accreting pulsar M82 X-2 from archival Chandra observations. Because M82 X-2 is known to have a 2.5-day orbital period, if the 55-day period is real, it will be the superorbital period of the system. We also investigated variabilities of other three nearby ultraluminous X-ray sources in the central region of M82 with the Chandra data and did not find any evidence of periodicities. Furthermore, we re-examined the previously reported 62-day periodicity near the central region of M82 by performing a systematic timing study with all the archival Rossi X-Ray Timing Explorer and Swift data. Using various dynamic timing analysis methods, we confirmed that the 62-day period is not stable, suggesting that it is not the orbital period of M82 X-1 in agreement with previous work.

Study of time resolution by digital methods with a DRS4 module**Supported by the Science Foundation of the Chinese Academy of Sciences (210340XBO), National Natural Science Foundation of China (11305233,11205222), General Program of National Natural Science Foundation of China (11475234), Specific Fund of National Key Scientific Instrument and Equipment Development Project (2011YQ12009604) and Joint Fund for Research Based on Large-Scale Scientific

A new Digital Pulse Processing (DPP) module has been developed, based on a domino ring sampler version 4 chip (DRS4), with good time resolution for LaBr3 detectors, and different digital timing analysis methods for processing the raw detector signals are reported. The module, composed of an eight channel DRS4 chip, was used as the readout electronics and acquisition system to process the output signals from XP20D0 photomultiplier tubes (PMTs). Two PMTs were coupled with LaBr3 scintillators and placed on opposite sides of a radioactive positron 22Na source for 511 keV γ-ray tests. By analyzing the raw data acquired by the module, the best coincidence timing resolution is about 194.7 ps (FWHM), obtained by the digital constant fraction discrimination (dCFD) method, which is better than other digital methods and analysis methods based on conventional analog systems which have been tested. The results indicate that it is a promising approach to better localize the positron annihilation in positron emission tomography (PET) with time of flight (TOF), as well as for scintillation timing measurement, such as in TOF-ΔE and TOF-E systems for particle identification, with picosecond accuracy timing measurement. Furthermore, this module is more simple and convenient than other systems.

Delineating ShallowS‐Wave Velocity Structure Using Multiple Ambient‐Noise Surface‐Wave Methods: An Example from Western Junggar, China

Abstract Aiming for a geophysical survey to around 1.5 km depth, we conduct a passive‐source surface‐wave survey along a 70‐km‐long line on the western side of the Junggar basin in northwest China. We use frequency–time analysis and spatial autocorrelation methods to extract surface‐wave dispersion curves from ambient‐noise data of station pairs, as well as ambient‐noise multichannel analysis of surface waves from multistations. Dispersion curves corresponding to the same positions obtained by these three methods independently are comparable, which shows the validity of using these methods. After inverting more than 400 dispersion curves and aligning their results together, we construct a 2D shear S ‐wave velocity image around 1.5 km deep and 60 km long. A less than 6% difference between the inverted S ‐wave velocity profile and the borehole data in situ shows the relatively high accuracy of our method. The 2D S ‐wave velocity image clearly delineates the main geologic structures, including transition of landform, intrusion of rock mass, and shape of bedrock beneath the survey line.

Research of Total Mechanical Energy of Steel Roof Truss during Structurally Nonlinear Oscillations

A mathematical model for the calculation of the discrete dissipative system total mechanical energy during free oscillations based on the method of time analysis was given. The features of this parameter behavior (jumps, asymptotes) for elastic structurally nonlinear systems were shown. A possible usage of the mathematical model is illustrated by the calculation of flat steel roof truss during oscillations caused by a sudden failure of one of the bearing elements due to corrosion effects.

Synthesis and structure of novel Ag2Ga2SiSe6 crystals: promising materials for dynamic holographic image recording

Phase diagrams of the AgGaSe2–SiSe2 system were explored by differential thermal analysis (DTA) and X-ray diffraction (XRD) analysis methods for the first time.

A Novel Logic for Analyzing Electronic Payment Protocols

A novel formal method which can be used to analyze security properties such as accountability, fairness and timeliness in electronic payment protocols is proposed. The novel method extends Qing-Zhou approach based on logic reasoning by adding a simple time expression and analysis method. It increases the ability to describe the event time, and extends the time characteristics of the logical inference rules. An anonymous electronic cash payment protocol is analyzed by the novel logic, and the result shows that the fairness of the protocol is not satisfied due to the timeliness problem in protocol. The novel logic method proposed in this paper has a certain theoretical and practical significance for the design and formal analysis of electronic payment protocols. At the same time, its idea has a certain guiding value for improving the security of other security protocols.

ДИНАМИЧЕСКИЙ РАСЧЁТ ФЕРМЫ ПОКРЫТИЯ ПРИ СВОБОДНЫХ КОНСТРУКТИВНО НЕЛИНЕЙНЫХ КОЛЕБАНИЯХ

A mathematical model of construction of the total mechanical energy of a discrete statically loaded dissipative system in the process of free oscillations in the form the time analysis method, which is based on the study of the characteristic quadratic matrix equation, was given. The features of the behavior of the parameters of the dynamic response when the elastic structurally nonlinear system to a new state was shown. It is also given the expressions to determine the kinematic (displacements, velocities, accelerations) and force (restoring, dissipative and inertial forces) parameters of the dynamic response. The criteria for assessing the load bearing capacity of the structure at the non-linear operation was suggested. Using a mathematical model is illustrated by the example of the calculation of flat steel statically indeterminate roof truss during the process of free oscillations, which was caused by a sudden failure of one of the bearing elements. Turning off the rod caused by the loss of strength as a result of chemical cracking due to corrosion effect.