scholarly journals Temperature Waves Phase Optimal Time Lag in the Refrigerated Warehouse Thermal Insulation

2021 ◽  
Author(s):  
Yurii MYRONCHUK ◽  
Mykhailo KHMELNİUK
Keyword(s):  
Thermal Insulation ◽  
Time Lag ◽  
Optimal Time ◽  
Temperature Waves

scholarly journals Normalized nonzero-lag crosscorrelation elastic full-waveform inversion

Geophysics ◽  
2019 ◽  
Vol 84 (1) ◽  
pp. R1-R10 ◽  
Author(s):  
Zhendong Zhang ◽  
Tariq Alkhalifah ◽  
Zedong Wu ◽  
Yike Liu ◽  
Bin He ◽  
...  
Keyword(s):  
Field Data ◽  
Extreme Values ◽  
Time Lag ◽  
Waveform Inversion ◽  
Optimal Time ◽  
Full Waveform Inversion ◽  
Data Set ◽  
Velocity Models ◽  
Full Waveform ◽  
The Earth

Full-waveform inversion (FWI) is an attractive technique due to its ability to build high-resolution velocity models. Conventional amplitude-matching FWI approaches remain challenging because the simplified computational physics used does not fully represent all wave phenomena in the earth. Because the earth is attenuating, a sample-by-sample fitting of the amplitude may not be feasible in practice. We have developed a normalized nonzero-lag crosscorrelataion-based elastic FWI algorithm to maximize the similarity of the calculated and observed data. We use the first-order elastic-wave equation to simulate the propagation of seismic waves in the earth. Our proposed objective function emphasizes the matching of the phases of the events in the calculated and observed data, and thus, it is more immune to inaccuracies in the initial model and the difference between the true and modeled physics. The normalization term can compensate the energy loss in the far offsets because of geometric spreading and avoid a bias in estimation toward extreme values in the observed data. We develop a polynomial-type weighting function and evaluate an approach to determine the optimal time lag. We use a synthetic elastic Marmousi model and the BigSky field data set to verify the effectiveness of the proposed method. To suppress the short-wavelength artifacts in the estimated S-wave velocity and noise in the field data, we apply a Laplacian regularization and a total variation constraint on the synthetic and field data examples, respectively.

scholarly journals Time-lag Analysis of Potential Waste Materials as Thermal Insulation in Tropical Climate: A Preliminary Investigation

2020 ◽  
Vol 498 ◽  
pp. 012100
Author(s):  
Dg Normaswanna Tawasil ◽  
Eeydzah Aminudin ◽  
Hasanah Abdul Shukor Lim ◽  
Rozana Zakaria ◽  
Hamdan bin Ahmad ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Preliminary Investigation ◽  
Time Lag ◽  
Tropical Climate ◽  
Waste Materials

scholarly journals Erosion of Endogenous Testosterone-Driven Negative Feedback on Pulsatile Luteinizing Hormone Secretion in Healthy Aging Men

2004 ◽  
Vol 89 (11) ◽  
pp. 5753-5761 ◽  
Author(s):  
Johannes D. Veldhuis ◽  
Ali Iranmanesh ◽  
Daniel M. Keenan
Keyword(s):  
Successful Aging ◽  
Healthy Aging ◽  
Time Lag ◽  
Hormone Secretion ◽  
Biological Marker ◽  
Sex Hormone Binding Globulin ◽  
Optimal Time ◽  
Elderly Subjects ◽  
Luteinizing Hormone Secretion ◽  
Aging Men

Abstract The present study tests the intuition that successful aging in men is marked by: 1) impaired feedforward by endogenous LH concentrations (con) of testosterone (Te) secretion (sec); and/or 2) attenuated feedback by unmanipulated Te con of LH sec. The goal was to assess both implicit linkages analytically without disrupting normal pathway coupling. This strategy required: 1) assay of paired LH and Te con sampled every 10 min for 24 h in 13 older (O) (ages 60–78 yr) and 13 young (Y) (ages 18–30 yr) men; 2) deconvolution-based estimation of LH and Te sec rates; 3) lag-specific cross-correlation analyses of the relationships between LH and Te con and sec; and 4) statistical contrasts by age stratum. Salient outcomes were: 1) O and Y men maintain comparable LH con drive of Te sec, viz maximal r = +0.51 and r = +0.52, respectively, at an optimal time lag of 50 min (both P < 0.001 against random LH and Te associations); 2) elderly subjects exhibit reduced Te con inhibition of LH sec [minimal r = −0.008 (O) vs. r = −0.10 (Y), P < 0.01 at a time lag of 40 min]; 3) mean (24-h) LH con do not differ by age; and 4) molar Te/sex hormone-binding globulin con are lower in the elderly than in Y individuals (P < 0.01). In conclusion, noninvasive analyses predict that attenuation of endogenous Te feedback restraint on the hypothalamo-pituitary unit may be an early biological marker of adaptive changes in the GnRH-LH-Te ensemble axis in the healthy O male.

scholarly journals Seasonal temperature waves in the ground, nonperiodic case

2021 ◽  
Vol 274 ◽  
pp. 04010
Author(s):  
Vsevolod Krepkogorskij
Keyword(s):  
Soil Temperature ◽  
Time Lag ◽  
Seasonal Temperature ◽  
Earth Surface ◽  
Temperature Deviation ◽  
Temperature Changes ◽  
The Earth ◽  
Periodic Law ◽  
Temperature Waves ◽  
Different Depths

Seasonal fluctuations in soil temperature at a depth of several meters are considered. It is assumed that the temperature of the earth surface changes strictly periodically. Then, according to the Fourier law, the soil temperature at depth will also change periodically with a smaller amplitude and time lag. What happens if we let the temperature on the surface deviate from the strict periodicity at some point in time? How will the nature of soil temperature fluctuations change at depth? Two types of deviations of the surface temperature from the periodic law are considered: 1) A sharp cold snap. For 30 days, the temperature of the earth surface is -30оC and 2) Warm winter. It is assumed that the temperature of the earth surface is zero during the winter months. Graphs of temperature changes at different depths in both cases are plotted. Conclusions are drawn about the duration of the period of noticeable deviations and the magnitude of the temperature deviation from the normal value.

scholarly journals Forecasting the COVID-19 epidemic integrating symptom search behavior: an infodemiology study

2021 ◽  
Author(s):  
Alessandro Rabiolo ◽  
Eugenio Alladio ◽  
Esteban Morales ◽  
Andrew I McNaught ◽  
Francesco Bandello ◽  
...  
Keyword(s):  
Time Series ◽  
Web Application ◽  
Moving Average ◽  
Time Lag ◽  
Search Behavior ◽  
Google Trends ◽  
Optimal Time ◽  
Time Range ◽  
Prediction Ability ◽  
Time Series Modelling

ABSTRACTBackgroundPrevious studies have suggested associations between trends of web searches and COVID-19 traditional metrics. It remains unclear whether models incorporating trends of digital searches lead to better predictions.MethodsAn open-access web application was developed to evaluate Google Trends and traditional COVID-19 metrics via an interactive framework based on principal components analysis (PCA) and time series modelling. The app facilitates the analysis of symptom search behavior associated with COVID-19 disease in 188 countries. In this study, we selected data of eight countries as case studies to represent all continents. PCA was used to perform data dimensionality reduction, and three different time series models (Error Trend Seasonality, Autoregressive integrated moving average, and feed-forward neural network autoregression) were used to predict COVID-19 metrics in the upcoming 14 days. The models were compared in terms of prediction ability using the root-mean-square error (RMSE) of the first principal component (PC1). Predictive ability of models generated with both Google Trends data and conventional COVID-19 metrics were compared with those fitted with conventional COVID-19 metrics only.FindingsThe degree of correlation and the best time-lag varied as a function of the selected country and topic searched; in general, the optimal time-lag was within 15 days. Overall, predictions of PC1 based on both searched termed and COVID-19 traditional metrics performed better than those not including Google searches (median [IQR]: 1.43 [0.74-2.36] vs. 1.78 [0.95-2.88], respectively), but the improvement in prediction varied as a function of the selected country and timeframe. The best model varied as a function of country, time range, and period of time selected. Models based on a 7-day moving average led to considerably smaller RMSE values as opposed to those calculated with raw data (median [IQR]: 0.74 [0.47-1.22] vs. 2.15 [1.55-3.89], respectively).InterpretationThe inclusion of digital online searches in statistical models may improve the prediction of the COVID-19 epidemic.FundingEOSCsecretariat.eu has received funding from the European Union’s Horizon Programme call H2020-INFRAEOSC-05-2018-2019, grant Agreement number 831644.

scholarly journals Time deals: optimization of lag

2019 ◽  
pp. 94-97
Author(s):  
Timofey Yu. Shabanov
Keyword(s):  
Business Processes ◽  
Time Lag ◽  
Optimal Time ◽  
Crop Failure ◽  
Agricultural Market ◽  
Potato Market ◽  
Current Period ◽  
Producer Prices ◽  
Analysis Of Dynamics ◽  
Annual Reduction

Relevance. In many ways, a successful purchase and sale transaction is determined by the time it takes to complete it. The search for the best deal time is linked to the optimization of the time lag. The purpose of the study is to optimize the time lag of the agricultural market.Methods. This article considered a role of time in business processes for Russian potato market of producer into period 1998-2018.Results. There was trend of annual reduction about 365 thousand tons (1.2...1.7% of total) per year supply of potatoes on Russian domestic market of producers. Some priority of quantity vs price of producer been revealed. There was inverse proportional function between producers` prices and quantity of potatoes. That is than worse harvest that higher producer`s price. Reducing a supply of potatoes 1 million tons from agricultural market perhaps increase in producer prices by $ 8.5 / t (4...5% on average). Offered concept and hypothesis about linearization of equilibrium of market processes into conditions of time shifts of dynamics their parameters were confirmed. There verified assumption about existence of inter-interval time optimum which this linearization maximal business processes. In course of correlation analysis of dynamics of annual indicators of potato market, it revealed month May of current period as optimal time of producer's offers with price restrictions and diminishing returns, and month September with quantity restrictions and increasing returns. If fixation of producer`s prices situation of deals May more likely, in case of crop failure (limited quantity) in September.

scholarly journals Multi-scale Modelling of Segmentation

2016 ◽  
Vol 34 (2) ◽  
pp. 192-217 ◽  
Author(s):  
Martín Hartmann ◽  
Olivier Lartillot ◽  
Petri Toiviainen
Keyword(s):  
Real Time ◽  
Time Scales ◽  
Time Lag ◽  
Optimal Time ◽  
Boundary Density ◽  
Multi Scale ◽  
Time Alignment ◽  
Scale Modelling ◽  
Time Segmentation ◽  
Segmentation Models

While listening to music, people often unwittingly break down musical pieces into constituent chunks such as verses and choruses. Music segmentation studies have suggested that some consensus regarding boundary perception exists, despite individual differences. However, neither the effects of experimental task (i.e., real-time vs. annotated segmentation), nor of musicianship on boundary perception are clear. Our study assesses musicianship effects and differences between segmentation tasks. We conducted a real-time experiment to collect segmentations by musicians and nonmusicians from nine musical pieces. In a second experiment on non-real-time segmentation, musicians indicated boundaries and their strength for six examples. Kernel density estimation was used to develop multi-scale segmentation models. Contrary to previous research, no relationship was found between boundary strength and boundary indication density, although this might be contingent on stimuli and other factors. In line with other studies, no musicianship effects were found: our results showed high agreement between groups and similar inter-subject correlations. Also consistent with previous work, time scales between one and two seconds were optimal for combining boundary indications. In addition, we found effects of task on number of indications, and a time lag between tasks dependent on beat length. Also, the optimal time scale for combining responses increased when the pulse clarity or event density decreased. Implications for future segmentation studies are raised concerning the selection of time scales for modelling boundary density, and time alignment between models.

scholarly journals Lacking Effects of Envelope Transcranial Alternating Current Stimulation Indicate the Need to Revise Envelope Transcranial Alternating Current Stimulation Methods

2020 ◽  
Vol 15 ◽  
pp. 263310552093662
Author(s):  
Jules Erkens ◽  
Michael Schulte ◽  
Matthias Vormann ◽  
Christoph S Herrmann
Keyword(s):  
Time Lag ◽  
Alternating Current ◽  
Optimal Time ◽  
Speech Comprehension ◽  
Time Lags ◽  
Beneficial Effects ◽  
Significant Difference ◽  
Transcranial Alternating Current Stimulation ◽  
Speech Envelope ◽  
Cortical Entrainment

In recent years, several studies have reported beneficial effects of transcranial alternating current stimulation (tACS) in experiments regarding sound and speech perception. A new development in this field is envelope-tACS: The goal of this method is to improve cortical entrainment to the speech signal by stimulating with a waveform based on the speech envelope. One challenge of this stimulation method is timing; the electrical stimulation needs to be phase-aligned with the naturally occurring cortical entrainment to the auditory stimuli. Due to individual differences in anatomy and processing speed, the optimal time-lag between presentation of sound and applying envelope-tACS varies between participants. To better investigate the effects of envelope-tACS, we performed a speech comprehension task with a larger amount of time-lags than previous experiments, as well as an equal amount of sham conditions. No significant difference between optimal stimulation time-lag condition and best sham condition was found. Further investigation of the data revealed a significant difference between the positive and negative half-cycles of the stimulation conditions but not for sham. However, we also found a significant learning effect over the course of the experiment which was of comparable size to the effects of envelope-tACS found in previous auditory tACS studies. In this article, we discuss possible explanations for why our findings did not match up with those of previous studies and the issues that come with researching and developing envelope-tACS.

scholarly journals OPTIMAL STOPPING WITH DELAYED INFORMATION

2005 ◽  
Vol 05 (02) ◽  
pp. 271-280 ◽  
Author(s):  
BERNT ØKSENDAL
Keyword(s):  
Optimal Stopping ◽  
Time Lag ◽  
Stopping Time ◽  
Resource Extraction ◽  
Optimal Time ◽  
Optimal Stopping Problem ◽  
Delayed Information ◽  
Optimal Resource ◽  
Flow Of Information ◽  
Strong Markov

We study a general optimal stopping problem for a strong Markov process in the case when there is a time lag δ > 0 from the time τ when the decision to stop is taken (a stopping time) to the time τ + δ when the system actually stops. Equivalently, we impose the constraint that the admissible times for stopping are stopping (Markov) times with respect to the delayed flow of information. It is shown that such a problem can be reduced to a classical optimal stopping problem by a simple transformation. The results are applied: (i) to find the optimal time to sell an asset (ii) to solve an optimal resource extraction problem, in both cases under delayed information flow.

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