scholarly journals Estimation of Raindrop Size Distribution Parameters Using Lightning Data over West Sumatra

2021 ◽  
Vol 13 (2) ◽  
pp. 92-100
Author(s):  
Faridah Salma ◽  
Marzuki Marzuki ◽  
Hiroyuki Hashiguchi ◽  
Fadli Nauval
Keyword(s):  
Time Interval ◽  
Short Time Interval ◽  
Time Intervals ◽  
Raindrop Size Distribution ◽  
West Sumatra ◽  
Distribution Parameters ◽  
Raindrop Size ◽  
The Tropics ◽  
Short Time

In situ observations of raindrop size distributions (DSDs) are still limited, especially in the tropics. Therefore, this study develops an alternative method to calculate DSD parameters by utilizing lightning data from the World-Wide Lightning Location Network (WWLLN) observation. DSD data was obtained from Parsivel's observations in the equatorial regions of Indonesia, i.e., Kototabang (100.32◦E, 0.20◦S, 865 m above mean sea level/ASL), Padang (100.46°E, 0.915°S, 200 m ASL), and Sicincin (100.30°E, 0.546°S, 134 m ASL). A gamma distribution parameterized the DSD. Three analysis domains were examined, with a grid of 0.1° x 0.1°, 0.5° x 0.5°, and 1° x 1°.  We examined the possibility to calculate the near-instantaneous DSD parameter, so three short time intervals, namely, one, five and ten minutes, were used. The results showed that the number of lightning strokes does not adequately correlate with DSD parameters. This is observed in all time intervals and analysis domains. Thus, the use of lightning data to calculate DSD parameters is not possible for short time interval of DSD (near instantaneous DSD). However, lightning data can estimate the average DSD parameters for an average time of more than one hour, as recommended by previous studies.

Active Optimum Control of Orthotropic Plates Using Piezoelectric Stiffeners

1993 ◽  
Author(s):  
Victor Birman ◽  
Sarp Adali
Keyword(s):  
Time Interval ◽  
Short Time Interval ◽  
Bending Moments ◽  
Optimum Control ◽  
Orthotropic Plates ◽  
Time Intervals ◽  
Control Forces ◽  
Short Time ◽  
Alternating Voltage ◽  
Over Time

Abstract Active control of orthotropic plates subjected to an impulse loading is considered. The dynamic response is minimized using in-plane forces or bending moments induced by piezoelectric stiffeners bonded to the opposite surfaces of the plate and placed symmetrically with respect to the middle plane. The control forces and moments are activated by a piece-wise constant alternating voltage with varying switch-over time intervals. The magnitude of voltage is bounded while the switch-over time intervals are constantly adjusted to achieve an optimum control. Numerical examples presented in the paper demonstrate the effectiveness of the method and the possibility of reducing the vibrations to very small amplitudes within a short time interval which is in the order of a second.

scholarly journals Design and interpretation of cell trajectory assays

2013 ◽  
Vol 10 (88) ◽  
pp. 20130630 ◽  
Author(s):  
Lucie G. Bowden ◽  
Matthew J. Simpson ◽  
Ruth E. Baker
Keyword(s):  
Cell Biology ◽  
Time Interval ◽  
Short Time Interval ◽  
Trajectory Data ◽  
Time Intervals ◽  
Different Types ◽  
Long Time ◽  
A Cell ◽  
Cell Trajectory ◽  
Short Time

Cell trajectory data are often reported in the experimental cell biology literature to distinguish between different types of cell migration. Unfortunately, there is no accepted protocol for designing or interpreting such experiments and this makes it difficult to quantitatively compare different published datasets and to understand how changes in experimental design influence our ability to interpret different experiments. Here, we use an individual-based mathematical model to simulate the key features of a cell trajectory experiment. This shows that our ability to correctly interpret trajectory data is extremely sensitive to the geometry and timing of the experiment, the degree of motility bias and the number of experimental replicates. We show that cell trajectory experiments produce data that are most reliable when the experiment is performed in a quasi-one-dimensional geometry with a large number of identically prepared experiments conducted over a relatively short time-interval rather than a few trajectories recorded over particularly long time-intervals.

Evaluation of time memory in acutely depressed patients, manic patients, and healthy controls using a time reproduction task

2008 ◽  
Vol 23 (6) ◽  
pp. 430-433 ◽  
Author(s):  
Richard Mahlberg ◽  
Thorsten Kienast ◽  
Tom Bschor ◽  
Mazda Adli
Keyword(s):  
Internal Clock ◽  
Time Interval ◽  
Short Time Interval ◽  
Time Intervals ◽  
Reproduction Task ◽  
Time Reproduction ◽  
Depressed Patients ◽  
Long Time ◽  
Short Time ◽  
Manic Patients

AbstractPatients with affective disorders have often been reported to experience subjective changes in how they perceive the flow of time. Time reproduction tasks provide information about the memory component of time perception and are thought to remain unaffected by pulse rate disturbances in the pacemaker of the internal clock.In our study, 30 patients with acute depression, 30 patients with acute mania, and 30 healthy subjects of all age groups were presented with a time reproduction task. Participants were asked to observe a stimulus presented on a computer screen for a certain length of time and, subsequently, to reproduce the stimulus for a similar length of time by pressing the space bar on the computer keyboard. Stimuli were presented to each subject for 1, 6, and 37 s.On average, the time intervals reproduced by manic patients were shorter than those reproduced by depressed patients. Manic patients reproduced the short time interval (6 s) correctly, but under-reproduced the long time interval (37 s, P < 0.001). Depressed patients correctly reproduced the long time interval, but over-reproduced the short time interval (P < 0.001).Remembering time intervals as having been longer than they actually were may lead to a slowed experience of time, as has been described in depressed patients; precisely the converse seems to apply to manic patients.

scholarly journals Halley’S Comet (Part I): Ground-based Observations

1989 ◽  
Vol 8 ◽  
pp. 3-16
Author(s):  
Richard M. West
Keyword(s):  
Space Missions ◽  
In Situ Measurements ◽  
Time Interval ◽  
Short Time Interval ◽  
International Programme ◽  
Halley's Comet ◽  
Large Telescopes ◽  
Short Time ◽  
Comet Halley

AbstractSince the recovery in October 1982, an extensive, international programme to observe Comet Halley with ground-based instruments has been co-ordinated by the International Halley Watch (IHW), and a comprehensive archive is now in the final phases of preparation. The observations were carried out at more than 150 observatories and with all available methods. A special effort was made to support the space missions during the comet encounters in early March 1986. Whereas the spacecraft provided detailed in-situ measurements over a short time interval, ground-based observers have so far followed the development of the comet over a period of nearly six years, and a number of spectacular events near the nucleus and in the tail have been documented in great detail. These observations still continue. This article gives an overview of the most important results obtained from the ground and also mentions the prospects for further observations with large telescopes during the next years.

scholarly journals Accuracy of Broiler Activity Index as Affected by Sampling Time Interval

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1102
Author(s):  
Xiao Yang ◽  
Yang Zhao ◽  
George T. Tabler
Keyword(s):  
Activity Index ◽  
Sampling Time ◽  
Time Interval ◽  
Short Time Interval ◽  
Time Intervals ◽  
Commercial Housing ◽  
Computational Resources ◽  
Short Time ◽  
Top View ◽  
Sampling Time Interval

Different time intervals between consecutive images have been used to determine broiler activity index (AI). However, the accuracy of broiler AI as affected by sampling time interval remains to be explored. The objective of this study was to investigate the effect of the sampling time interval (0.04, 0.2, 1, 10, 60, and 300 s) on the accuracy of broiler AI at different bird ages (1–7 weeks), locations (feeder, drinker, and open areas) and times of day (06:00–07:00 h, 12:00–13:00 h, and 18:00–19:00 h). A ceiling-mounted camera was used to capture top-view videos for broiler AI calculations. The results show that the sampling time interval of 0.04 s yielded the highest broiler AI because more bird motion details were captured at this short time interval. The broiler AIs at longer time intervals were 1–99% of that determined at the 0.04-s interval. The broiler AI at 0.2-s interval showed an acceptable accuracy with 80% less computational resources. Broiler AI decreased as birds aged but increased after week 4 at the drinker area. Broiler AI was the highest at the open area for weeks 1–4 and at the feeder and drinker areas for weeks 5–7. It is concluded that the accuracy of broiler AI was significantly affected by sampling time intervals. Broiler AI in commercial housing showed both temporal and spatial variations.

scholarly journals Neural Network Approach for Global Solar Irradiance Prediction at Extremely Short-Time-Intervals Using Particle Swarm Optimization Algorithm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1213
Author(s):  
Ahmed Aljanad ◽  
Nadia M. L. Tan ◽  
Vassilios G. Agelidis ◽  
Hussain Shareef
Keyword(s):  
Neural Networks ◽  
Particle Swarm Optimization ◽  
Solar Irradiance ◽  
Particle Swarm ◽  
Time Interval ◽  
Time Intervals ◽  
Swarm Optimization ◽  
Backpropagation Neural Networks ◽  
Proposed Model ◽  
Short Time

Hourly global solar irradiance (GSR) data are required for sizing, planning, and modeling of solar photovoltaic farms. However, operating and controlling such farms exposed to varying environmental conditions, such as fast passing clouds, necessitates GSR data to be available for very short time intervals. Classical backpropagation neural networks do not perform satisfactorily when predicting parameters within short intervals. This paper proposes a hybrid backpropagation neural networks based on particle swarm optimization. The particle swarm algorithm is used as an optimization algorithm within the backpropagation neural networks to optimize the number of hidden layers and neurons used and its learning rate. The proposed model can be used as a reliable model in predicting changes in the solar irradiance during short time interval in tropical regions such as Malaysia and other regions. Actual global solar irradiance data of 5-s and 1-min intervals, recorded by weather stations, are applied to train and test the proposed algorithm. Moreover, to ensure the adaptability and robustness of the proposed technique, two different cases are evaluated using 1-day and 3-days profiles, for two different time intervals of 1-min and 5-s each. A set of statistical error indices have been introduced to evaluate the performance of the proposed algorithm. From the results obtained, the 3-days profile’s performance evaluation of the BPNN-PSO are 1.7078 of RMSE, 0.7537 of MAE, 0.0292 of MSE, and 31.4348 of MAPE (%), at 5-s time interval, where the obtained results of 1-min interval are 0.6566 of RMSE, 0.2754 of MAE, 0.0043 of MSE, and 1.4732 of MAPE (%). The results revealed that proposed model outperformed the standalone backpropagation neural networks method in predicting global solar irradiance values for extremely short-time intervals. In addition to that, the proposed model exhibited high level of predictability compared to other existing models.

scholarly journals Optimal Perturbations of an Oceanic Vortex Lens

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Thomas Meunier ◽  
Claire Ménesguen ◽  
Xavier Carton ◽  
Sylvie Le Gentil ◽  
Richard Schopp
Keyword(s):  
Normal Mode ◽  
Growth Rates ◽  
Time Interval ◽  
Time Intervals ◽  
Horizontal Structure ◽  
Azimuthal Wave ◽  
Wave Numbers ◽  
Non Linear ◽  
Long Time ◽  
Short Time

The stability properties of a vortex lens are studied in the quasi geostrophic (QG) framework using the generalized stability theory. Optimal perturbations are obtained using a tangent linear QG model and its adjoint. Their fine-scale spatial structures are studied in details. Growth rates of optimal perturbations are shown to be extremely sensitive to the time interval of optimization: The most unstable perturbations are found for time intervals of about 3 days, while the growth rates continuously decrease towards the most unstable normal mode, which is reached after about 170 days. The horizontal structure of the optimal perturbations consists of an intense counter-shear spiralling. It is also extremely sensitive to time interval: for short time intervals, the optimal perturbations are made of a broad spectrum of high azimuthal wave numbers. As the time interval increases, only low azimuthal wave numbers are found. The vertical structures of optimal perturbations exhibit strong layering associated with high vertical wave numbers whatever the time interval. However, the latter parameter plays an important role in the width of the vertical spectrum of the perturbation: short time interval perturbations have a narrow vertical spectrum while long time interval perturbations show a broad range of vertical scales. Optimal perturbations were set as initial perturbations of the vortex lens in a fully non linear QG model. It appears that for short time intervals, the perturbations decay after an initial transient growth, while for longer time intervals, the optimal perturbation keeps on growing, quickly leading to a non-linear regime or exciting lower azimuthal modes, consistent with normal mode instability. Very long time intervals simply behave like the most unstable normal mode. The possible impact of optimal perturbations on layering is also discussed.

Estimation of Time-Dependent Turning Fractions at Signalized Intersections

1998 ◽  
Vol 1644 (1) ◽  
pp. 142-149 ◽  
Author(s):  
Gang-Len Chang ◽  
Xianding Tao
Keyword(s):  
Signalized Intersections ◽  
Efficient Estimation ◽  
Estimation Accuracy ◽  
Time Interval ◽  
Short Time Interval ◽  
Simulation Experiments ◽  
Proposed Model ◽  
Short Time ◽  
Estimation Of Time ◽  
Additional Constraints

An effective method for estimating time-varying turning fractions at signalized intersections is described. With the inclusion of approximate intersection delay, the proposed model can account for the impacts of signal setting on the dynamic distribution of intersection flows. To improve the estimation accuracy, the use of preestimated turning fractions from a relatively longer time interval has been proposed to serve as additional constraints for the same estimation but over a short time interval. The results of extensive simulation experiments indicated that the proposed method can yield sufficiently accurate as well as efficient estimation of dynamic turning fractions for signalized intersections.

Micro-Expression Recognition using 3D - CNN

2020 ◽  
pp. 5-13
Author(s):  
Vishal Dubey ◽  
◽  
◽  
◽  
Bhavya Takkar ◽  
...  
Keyword(s):  
Emotional Response ◽  
High Speed ◽  
Actual State ◽  
Time Interval ◽  
Short Time Interval ◽  
Expression Recognition ◽  
Specific Emotion ◽  
3D Cnn ◽  
Short Time ◽  
Micro Expression

Micro-expression comes under nonverbal communication, and for a matter of fact, it appears for minute fractions of a second. One cannot control micro-expression as it tells about our actual state emotionally, even if we try to hide or conceal our genuine emotions. As we know that micro-expressions are very rapid due to which it becomes challenging for any human being to detect it with bare eyes. This subtle-expression is spontaneous, and involuntary gives the emotional response. It happens when a person wants to conceal the specific emotion, but the brain is reacting appropriately to what that person is feeling then. Due to which the person displays their true feelings very briefly and later tries to make a false emotional response. Human emotions tend to last about 0.5 - 4.0 seconds, whereas micro-expression can last less than 1/2 of a second. On comparing micro-expression with regular facial expressions, it is found that for micro-expression, it is complicated to hide responses of a particular situation. Micro-expressions cannot be controlled because of the short time interval, but with a high-speed camera, we can capture one's expressions and replay them at a slow speed. Over the last ten years, researchers from all over the globe are researching automatic micro-expression recognition in the fields of computer science, security, psychology, and many more. The objective of this paper is to provide insight regarding micro-expression analysis using 3D CNN. A lot of datasets of micro-expression have been released in the last decade, we have performed this experiment on SMIC micro-expression dataset and compared the results after applying two different activation functions.

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