scholarly journals Identification of ionospheric earthquake precursors in Kamchatka region based on correlation analysis

2021 ◽  
pp. 150-158
Author(s):  
В.В. Богданов ◽  
А.В. Павлов
Keyword(s):  
Statistical Analysis ◽  
Correlation Coefficient ◽  
Critical Frequency ◽  
Earthquake Precursors ◽  
The Other ◽  
Concentration Change ◽  
Strong Earthquakes ◽  
Ionospheric Variability ◽  
Kamchatka Region ◽  
Critical Frequency Fof2

Сейсмическая активность является одним из источников изменчивости ионосферы. В данной работе на основе методики [1] исследовано изменение концентрации электронов в ионосфере, предшествующее наступлению сильных землетрясений с M ≥ 6.0 в Камчатском регионе. Данная методика основана на вычислении коэффициента корреляции между значениями критической частоты foF2 двух ионосферных станций, одна из которых расположена внутри зоны подготовки землетрясения, а другая – за ее пределами. Рассмотрены данные, полученные на двух станциях PETROPAVLOVSK (PK553) и EARECKSON (EA653) за период 01.09.2018–30.04.2021 гг. Статистический анализ критических частот foF2 показал, что для 6 из 8 землетрясений с M ≥ 6.0, произошедших на глубинах до 100 км и эпицентральных расстояниях до 500 км от расположения PK553, за 1–12 суток до их наступления предшествовало заметное уменьшение коэффициента корреляции. Seismic activity is one of the sources of ionospheric variability. In this work, we investigate electron concentration change in the ionosphere, preceding the onset of strong earthquakes with M ≥ 6.0 in Kamchatka region. The research technique is based on calculating the correlation coefficient between the critical frequency foF2 values at two ionospheric stations. One of them is located inside the earthquake preparation zone, and the other is outside it. The data obtained at two stations PETROPAVLOVSK (PK553) and EARECKSON (EA653) for the period 01.09.2018–30.04.2021 are considered. Statistical analysis of the critical frequencies foF2 showed that a noticeable decrease in the correlation coefficient was observed 1–7 days before the earthquakes for 6 out of 8 events with M ≥ 6.0 that occurred at depths of up to 100 km and epicentral distances of up to 500 km from the PK553 location.

scholarly journals Analysis of the efficiency of earthquake prediction based on the anomalous behavior of ionospheric parameters on the eve of earthquakes in the Kamchatka region

2018 ◽  
Vol 62 ◽  
pp. 03001 ◽  
Author(s):  
Vadim Bogdanov ◽  
Aleksey Pavlov
Keyword(s):  
Critical Frequency ◽  
Anomalous Behavior ◽  
Seismic Events ◽  
Ionospheric Disturbances ◽  
Short Term ◽  
Strong Earthquakes ◽  
Perturbed State ◽  
Kamchatka Region ◽  
Spread F ◽  
Short Term Prediction

A method is presented for short-term prediction of strong earthquakes, in which the precursors are considered the excess of current values of foF2 critical frequency of the ionospheric F2 layer over the median values in periods of perturbed state of the magnetosphere, the appearance of ionospheric disturbances: K-layer, Es-spread F-spread, the stratification of the F2 layer, Es is the r type. As predicted earthquakes were considered earthquakes with magnitudes M ≥ 5:0. Assessment of the effectiveness of the forecast was carried out in the spring and autumn periods for 2013–2017 according to the methods of A. A. Gusev and G. M. Molchan. It is shown that the method under consideration has the best prognostic efficiency for seismic events with M ≥ 6:5 magnitude.

scholarly journals Effect of time factor, spray feeding of Copper and Iron in the relation between the number of bacterial root nodules and leaves of Bean

2011 ◽  
Vol 5 (3) ◽  
pp. 45-55
Author(s):  
Ali Sabeeh Abdulameer
Keyword(s):  
Statistical Analysis ◽  
Correlation Coefficient ◽  
Root Nodules ◽  
Time Factor ◽  
The Other ◽  
Control Treatment ◽  
Water Spray ◽  
Spring Season ◽  
Positive Significant Correlation ◽  
Treatment Water

pot experiment was carried out during the spring season in the year 2008 to investigate the effect of the time factor, spray feeding of copper and Iron on the relation between the number of nodules and leaves of Beans. The statistical analysis showed that spray feeding of copper and Iron exceed significantly on the control treatment (water spray feeding), also, the spray feeding of Iron after 20 days of seeding excelled significantly on the spray feeding of Iron after 30 days of seeding, as well as the Spanish type of seed surpassed significantly on the Brazilian kind of seed in the number of root nodules and leaves of bean. On the other hand the studied characteristics appeared positive significant correlation coefficient (r=0.899). The interaction (overlap) treatment Cu1×S2×Fe1 recorded the highest values in both root nodules and leaves of bean by 9.00 nodule/ plant and 59.33 leaves/ plant, respectively.

scholarly journals Estimation earthquake occurrence probability in Kamchatka region based on seismological and complex of ionospheric precursors

2021 ◽  
Vol 254 ◽  
pp. 03003
Author(s):  
Vadim Boganov ◽  
Aleksey Pavlov
Keyword(s):  
Probabilistic Model ◽  
Critical Frequency ◽  
Occurrence Probability ◽  
Earthquake Occurrence ◽  
Short Term ◽  
Bayes Method ◽  
Strong Earthquakes ◽  
Seismic Regime ◽  
Waiting Period ◽  
Kamchatka Region

In this paper the authors present the method of estimation of a region, waiting period and probability of strong earthquakes with KS ≥ 13.5 (M ≥ 6.0) in Kamchatka region based on the combination of mid-term and short-term predictive signs accompanying earthquake formation. The seismological predictive parameter ξP was taken as a mid-term precursor. It was calculated on the basis of the probabilistic model of seismic regime. A complex of ionospheric parameters was considered as short-term predictive signs with an earthquake waiting period of up to 5 days. It includes the K-layer, the sporadic Es layer of the r type, the critical frequency foF2, and the frequency stratification of the F2 layer. The probabilities of strong earthquakes with KS ≥ 13.5 (M ≥ 6.0) that occurred over the period 2019–2021 in an expected zone, determined by the parameter ξP, were estimated on the basis of Bayes method provided that a complex of anomalous parameters of the ionosphere was identified.

scholarly journals Proposal of an Adaptive Neurofuzzy System to Control Flow Power in Distributed Generation Systems

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Helbert Eduardo Espitia ◽  
Iván Machón-González ◽  
Hilario López-García ◽  
Guzmán Díaz
Keyword(s):  
Statistical Analysis ◽  
Distributed Generation ◽  
Distribution System ◽  
Voltage Control ◽  
Control Flow ◽  
The Other ◽  
Charge Variation ◽  
Flow Power ◽  
Dynamics Identification ◽  
Neurofuzzy Systems

Systems of distributed generation have shown to be a remarkable alternative to a rational use of energy. Nevertheless, the proper functioning of them still manifests a range of challenges, including both the adequate energy dispatch depending on the variability of consumption and the interaction between generators. This paper describes the implementation of an adaptive neurofuzzy system for voltage control, regarding the changes observed in the consumption within the distribution system. The proposed design employs two neurofuzzy systems, one for the plant dynamics identification and the other for control purposes. This focus optimizes the controller using the model achieved through the identification of the plant, whose changes are produced by charge variation; consequently, this process is adaptively performed. The results show the performance of the adaptive neurofuzzy system via statistical analysis.

Was This in Your Statistics Textbook? IV. Frequency Data

1989 ◽  
Vol 25 (1) ◽  
pp. 11-25
Author(s):  
D. J. Finney
Keyword(s):  
Statistical Analysis ◽  
Contingency Tables ◽  
The Other ◽  
Frequency Data ◽  
Significance Tests ◽  
Test Statistic ◽  
Jumping To Conclusions ◽  
Proper Role ◽  
Measure Of Association

SUMMARYObservations that are frequencies rather than measurements often call for special types of statistical analysis. This paper comments on circumstances in which methods for one type of data can sensibly be used for the other. A section on two-way contingency tables emphasizes the proper role of χ2 a test statistic but not a measure of association; it mentions the distinction between one-tail and two-tail significance tests and reminds the reader of dangers. Multiway tables bring new complications, and the problems of interactions when additional classificatory factors are explicit or hidden are discussed at some length. A brief outline attempts to show how probit, logit, and similar techniques are related to the analysis of contingency tables. Finally, three unusual examples are described as illustrations of the care that is needed to avoid jumping to conclusions on how frequency data should be analysed.

Changes in Nutrient Levels of Lake Water Stored at 4 °C

1984 ◽  
Vol 41 (6) ◽  
pp. 985-988 ◽  
Author(s):  
A. H. El-Shaarawi ◽  
M. A. Neilson
Keyword(s):  
Statistical Analysis ◽  
Lake Water ◽  
Water Samples ◽  
Soluble Reactive Phosphorus ◽  
Lake Ontario ◽  
The Other ◽  
Nutrient Levels ◽  
Glass Bottles ◽  
Reactive Phosphorus

Water samples were collected on Lake Ontario during April and November, filtered (0.45 μm), and immediately analyzed onboard ship for the nutrients soluble reactive phosphorus, nitrate-plus-nitrite, and ammonia. Replicates were stored in glass bottles at 4 °C and reanalyzed within 8 d. Statistical analysis showed that soluble reactive phosphorus decreased by 11 and 13% and nitrate-plus-nitrite by 7 and 6%, whereas ammonia increased by 75% on one cruise and decreased by 37% on the other.

Alarm systems based on a pair of short-term earthquake precursors

1988 ◽  
Vol 78 (4) ◽  
pp. 1538-1549
Author(s):  
Giuseppe Grandori ◽  
Elisa Guagenti ◽  
Federico Perotti
Keyword(s):  
Statistical Analysis ◽  
Active Region ◽  
Southern California ◽  
Main Shock ◽  
Weak Shock ◽  
Earthquake Precursors ◽  
Alarm System ◽  
Short Term ◽  
Alarm Systems

Abstract A statistical analysis of the foreshock-main shock correlation for a seismically active region in Italy is presented. It is found that the probability that a weak shock be followed within 2 days by a main shock is of the order of 2 per cent, while the probability that a main shock be preceded by a foreshock is of the order of 50 per cent. These results are quite similar to those found by L. Jones (1985) for southern California. The effectiveness of alarm systems based on a pair of short-term earthquake precursors is then analyzed. In particular, the analysis shows under what conditions the precursor, consisting of potential foreshocks, could be combined with another precursor to provide a reasonably effective alarm system.

scholarly journals Hypermobility and sports injury

2018 ◽  
Vol 4 (1) ◽  
pp. e000366 ◽  
Author(s):  
Joseph Alexander Nathan ◽  
Kevin Davies ◽  
Ian Swaine
Keyword(s):  
Statistical Analysis ◽  
Sports Injury ◽  
The Other ◽  
Anecdotal Evidence ◽  
Demographic Information ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Exact Test ◽  
Joint Dislocation ◽  
Ligament Sprain

ObjectiveTo determine whether there is an association between hypermobility and sports injury.MethodsA quantitative observational approach using a cross-sectional survey was adopted. Individuals were identified as hypermobile or not. All participants were asked to complete two questionnaires: one asking demographic information and the other injury-specific. Fisher’s exact test was used for statistical analysis.Results114 individuals participated in the study, 62 women and 52 men. 26% of the participants were hypermobile. There was no significant association between hypermobility and sports injury (p=0.66). There was a significant increase in joint and ligament sprain among the non-hypermobile (NH) group covering all sports (p=0.03). Joint dislocation was found exclusively among hypermobile individuals. The duration of injury in hypermobile individuals was higher than NH. The use of oral painkillers or anti-inflammatories in the semiprofessional group was greater than the general population.ConclusionHypermobility is relatively common among individuals, and there is a lot of anecdotal evidence associating it with increased rates of injuries. This project finds that NH individuals are more likely to sustain a ligament or joint sprain in sports. This is due to increased joint laxity and flexibility preventing injury. There were important limitations to this study which will be addressed in further work. These include assessing for pauciarticular hypermobility and focusing on one sport to investigate its association with sports injury in those who are hypermobile or not. It would also be important to focus on one specific joint, assessing its flexibility and association with injury.

scholarly journals The Influence of Design Parameters on Straight Bevel Gear Dynamics

2015 ◽  
Vol 5 (2) ◽  
pp. 114
Author(s):  
Chiu-Fan Hsieh ◽  
You-Qing Zhu
Keyword(s):  
Statistical Analysis ◽  
The Other ◽  
Design Parameters ◽  
Bevel Gears ◽  
Straight Bevel Gear ◽  
Pressure Angle ◽  
Stress Fluctuation ◽  
Shaft Angle ◽  
Statistical Results ◽  
Component Force

<p class="1Body">This study analyzes the influence of design parameters on the dynamics of straight bevel gears by constructing a model that allows variation in the shaft angle, pressure angle, and backlash. According to the statistical analysis, the order of influence of these parameters on weight is shaft angle &gt; pressure angle &gt; backlash. When the shaft angle is 90°, the statistical results show the drive is stable and the stress fluctuation level is low. The pressure angle, on the other hand, can affect the gear’s dynamic property by influencing the driving component force on the gear and the component force on the shaft. The results for the shaft and pressure angles are used to determine the appropriate backlash. Overall, the analysis not only provides designers with an important reference but explains the dominance in the market of gear designs with a 90° shaft angle and a 20° pressure angle.</p>

Statistics and Economic History

1941 ◽  
Vol 1 (1) ◽  
pp. 26-41 ◽  
Author(s):  
Simon Kuznets
Keyword(s):  
Statistical Analysis ◽  
Economic History ◽  
Raw Materials ◽  
The Other ◽  
Economic Study ◽  
Statistical Research ◽  
Historical Approach ◽  
The Past ◽  
Economic Inquiry ◽  
Analytical Tools

This paper deals with the relation between statistical analysis as applied in economic inquiry and history as written or interpreted by economic historians. Although both these branches of economic study derive from the same body of raw materials of inquiry—the recordable past and present of economic society—each has developed in comparative isolation from the other. Statistical economists have failed to utilize adequately the contributions that economic historians have made to our knowledge of the past; and historians have rarely employed either the analytical tools or the basic theoretical hypotheses of statistical research. It is the thesis of this essay that such failure to effect a close interrelation between historical approach and statistical analysis needs to be corrected in the light of the final goal of economic study.

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