scholarly journals Parameter estimation of a dual-pol radar rain rate estimator with truncated paired data

2020 ◽  
Vol 20 (7) ◽  
pp. 2616-2629
Author(s):  
Jung Mo Ku ◽  
Wooyoung Na ◽  
Chulsang Yoo
Keyword(s):  
Parameter Estimation ◽  
Gaussian Distribution ◽  
Rain Rate ◽  
Dominant Role ◽  
The Other ◽  
Paired Data ◽  
Rainfall Events ◽  
Normal Ranges ◽  
Radar Rain Rate ◽  
Differential Reflectivity

Abstract This study proposes a new method for estimating the parameters of a radar rain rate estimator, particularly of the dual-pol radar. The proposed method is similar to the probability matching method (PMM), except for being based on truncated data pairs. A truncation value is introduced to the log-transformed data in order to remove those in the low rain rate zone as well as to introduce Gaussian distribution. The parameters are then estimated by comparing the first- and second-order moments. The proposed method is applied to a total of six rainfall events observed by the Beaslesan Radar in Korea from 2014 to 2017. Summarizing the results, first, the truncation value should be applied to the horizontal reflectivity (dBZh) data. In this case only, the other two data, the rain rate (dBR) and the differential reflectivity (dBZdr), follow the Gaussian distribution well. It is also important to consider rather severe rainfall events for the parameter estimation. The parameters for only the severe rainfall events are all estimated rather reasonably. On the other hand, for the other moderate and light rainfall events, the parameters are estimated as being rather far from their normal ranges. This is mainly due to the relatively small variance of dBR compared to that of dBZh. That is, the variance of dBR is found to be greatly dependent on the peak rain rate, but the variance of dBZh remains almost unchanged, regardless of the peak rain rate. As a result, the peak rain rate plays a dominant role in the reasonable parameter estimation. These findings are also consistent with many previous studies.

scholarly journals Radar Rain-Rate Estimators and Their Variability due to Rainfall Type: An Assessment Based on Hydrometeorology Testbed Data from the Southeastern United States

2016 ◽  
Vol 55 (6) ◽  
pp. 1345-1358 ◽  
Author(s):  
Sergey Y. Matrosov ◽  
Robert Cifelli ◽  
Paul J. Neiman ◽  
Allen B. White
Keyword(s):  
Rain Rate ◽  
Convective Precipitation ◽  
Differential Phase ◽  
Convective Rain ◽  
Rainfall Type ◽  
Radar Measurements ◽  
The Common ◽  
Drop Size Distributions ◽  
Radar Rain Rate ◽  
Differential Reflectivity

AbstractS-band profiling (S-PROF) radar measurements from different southeastern U.S. Hydrometeorology Testbed sites indicated a frequent occurrence of rain that did not exhibit radar bright band (BB) and was observed outside the periods of deep-convective precipitation. This common nonbrightband (NBB) rain contributes ~15%–20% of total accumulation and is not considered as a separate rain type by current precipitation-segregation operational radar-based schemes, which separate rain into stratiform, convective, and, sometimes, tropical types. Collocated with S-PROF, disdrometer measurements showed that drop size distributions (DSDs) of NBB rain have much larger relative fractions of smaller drops when compared with those of BB and convective rains. Data from a year of combined DSD and rain-type observations were used to derive S-band-radar estimators of rain rate R, including those based on traditional reflectivity Ze and ones that also use differential reflectivity ZDR and specific differential phase KDP. Differences among same-type estimators for mostly stratiform BB and deep-convective rain were relatively minor, but estimators derived for the common NBB rain type were distinct. Underestimations in NBB rain-rate retrievals derived using other rain-type estimators (e.g., those for BB or convective rain or default operational radar estimators) for the same values of radar variables can be on average about 40%, although the differential phase-based estimators are somewhat less susceptible to DSD details. No significant differences among the estimators for the same rain type derived using DSDs from different observational sites were present despite significant separation and differing terrain. Identifying areas of common NBB rain could be possible from Ze and ZDR measurements.

Plasma Levels of Protein S, Protein C, and Factor X: Effects of Sex, Hormonal State and Age

1995 ◽  
Vol 74 (05) ◽  
pp. 1271-1275 ◽  
Author(s):  
C M A Henkens ◽  
V J J Bom ◽  
W van der Schaaf ◽  
P M Pelsma ◽  
C Th Smit Sibinga ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Postmenopausal Women ◽  
Protein C ◽  
Blood Donors ◽  
Premenopausal Women ◽  
Protein S ◽  
The Other ◽  
Factor X ◽  
Normal Ranges

SummaryWe measured total and free protein S (PS), protein C (PC) and factor X (FX) in 393 healthy blood donors to assess differences in relation to sex, hormonal state and age. All measured proteins were lower in women as compared to men, as were levels in premenopausal women as compared to postmenopausal women. Multiple regression analysis showed that both age and subgroup (men, pre- and postmenopausal women) were of significance for the levels of total and free PS and PC, the subgroup effect being caused by the differences between the premenopausal women and the other groups. This indicates a role of sex-hormones, most likely estrogens, in the regulation of levels of pro- and anticoagulant factors under physiologic conditions. These differences should be taken into account in daily clinical practice and may necessitate different normal ranges for men, pre- and postmenopausal women.

scholarly journals Hiketeia

1973 ◽  
Vol 93 ◽  
pp. 74-103 ◽  
Author(s):  
John Gould
Keyword(s):  
Dominant Role ◽  
Ancient Greece ◽  
Social Institutions ◽  
The Other ◽  
Sixth Century ◽  
Dead Body ◽  
Greek Literature ◽  
The World ◽  
The One ◽  
Working Out

To Professor E. R. Dodds, through his edition of Euripides'Bacchaeand again inThe Greeks and the Irrational, we owe an awareness of new possibilities in our understanding of Greek literature and of the world that produced it. No small part of that awareness was due to Professor Dodds' masterly and tactful use of comparative ethnographic material to throw light on the relation between literature and social institutions in ancient Greece. It is in the hope that something of my own debt to him may be conveyed that this paper is offered here, equally in gratitude, admiration and affection.The working out of the anger of Achilles in theIliadbegins with a great scene of divine supplication in which Thetis prevails upon Zeus to change the course of things before Troy in order to restore honour to Achilles; it ends with another, human act in which Priam supplicates Achilles to abandon his vengeful treatment of the dead body of Hector and restore it for a ransom. The first half of theOdysseyhinges about another supplication scene of crucial significance, Odysseus' supplication of Arete and Alkinoos on Scherie. Aeschylus and Euripides both wrote plays called simplySuppliants, and two cases of a breach of the rights of suppliants, the cases of the coup of Kylon and that of Pausanias, the one dating from the mid-sixth century, the other from around 470 B.C. or soon after, played a dominant role in the diplomatic propaganda of the Spartans and Athenians on the eve of the Peloponnesian War.

scholarly journals On a characterization theorem on a-adic solenoids

2019 ◽  
Vol 489 (3) ◽  
pp. 227-231
Author(s):  
G. M. Feldman
Keyword(s):  
Gaussian Distribution ◽  
Real Line ◽  
Linear Form ◽  
Conditional Distribution ◽  
Random Variables ◽  
Characterization Theorem ◽  
The Other ◽  
Independent Random Variables ◽  
Linear Forms ◽  
The Real

According to the Heyde theorem the Gaussian distribution on the real line is characterized by the symmetry of the conditional distribution of one linear form of independent random variables given the other. We prove an analogue of this theorem for linear forms of two independent random variables taking values in an -adic solenoid containing no elements of order 2. Coefficients of the linear forms are topological automorphisms of the -adic solenoid.

scholarly journals Autonomous Vehicles: Vehicle Parameter Estimation Using Variational Bayes and Kinematics

2020 ◽  
Vol 10 (18) ◽  
pp. 6317 ◽  
Author(s):  
Wilfried Wöber ◽  
Georg Novotny ◽  
Lars Mehnen ◽  
Cristina Olaverri-Monreal
Keyword(s):  
Parameter Estimation ◽  
Autonomous Vehicles ◽  
Autonomous Driving ◽  
The Other ◽  
Sensor Data ◽  
Critical Feature ◽  
Motion Data ◽  
Movement Data ◽  
End Use ◽  
Vehicle Movement

On-board sensory systems in autonomous vehicles make it possible to acquire information about the vehicle itself and about its relevant surroundings. With this information the vehicle actuators are able to follow the corresponding control commands and behave accordingly. Localization is thus a critical feature in autonomous driving to define trajectories to follow and enable maneuvers. Localization approaches using sensor data are mainly based on Bayes filters. Whitebox models that are used to this end use kinematics and vehicle parameters, such as wheel radii, to interfere the vehicle’s movement. As a consequence, faulty vehicle parameters lead to poor localization results. On the other hand, blackbox models use motion data to model vehicle behavior without relying on vehicle parameters. Due to their high non-linearity, blackbox approaches outperform whitebox models but faulty behaviour such as overfitting is hardly identifiable without intensive experiments. In this paper, we extend blackbox models using kinematics, by inferring vehicle parameters and then transforming blackbox models into whitebox models. The probabilistic perspective of vehicle movement is extended using random variables representing vehicle parameters. We validated our approach, acquiring and analyzing simulated noisy movement data from mobile robots and vehicles. Results show that it is possible to estimate vehicle parameters with few kinematic assumptions.

scholarly journals RainFARM: Rainfall Downscaling by a Filtered Autoregressive Model

2006 ◽  
Vol 7 (4) ◽  
pp. 724-738 ◽  
Author(s):  
Nicola Rebora ◽  
Luca Ferraris ◽  
Jost von Hardenberg ◽  
Antonello Provenzale
Keyword(s):  
Random Field ◽  
Autoregressive Model ◽  
Gaussian Random Field ◽  
Statistical Properties ◽  
The Other ◽  
Small Scale ◽  
Intense Rainfall ◽  
Rainfall Events ◽  
The Tropics ◽  
Meteorological Models

Abstract A method is introduced for stochastic rainfall downscaling that can be easily applied to the precipitation forecasts provided by meteorological models. Our approach, called the Rainfall Filtered Autoregressive Model (RainFARM), is based on the nonlinear transformation of a Gaussian random field, and it conserves the information present in the rainfall fields at larger scales. The procedure is tested on two radar-measured intense rainfall events, one at midlatitude and the other in the Tropics, and it is shown that the synthetic fields generated by RainFARM have small-scale statistical properties that are consistent with those of the measured precipitation fields. The application of the disaggregation procedure to an example meteorological forecast illustrates how the method can be implemented in operational practice.

DISTRIBUTION OF VOTES AND A MODEL OF POLITICAL OPINION FORMATION FOR MAJORITY ELECTIONS

2012 ◽  
Vol 16 ◽  
pp. 1-12 ◽  
Author(s):  
DODE PRENGA ◽  
MARGARITA IFTI
Keyword(s):  
Power Law ◽  
Gaussian Distribution ◽  
Similar Pattern ◽  
Word Of Mouth ◽  
Preferential Attachment ◽  
The Other ◽  
Opinion Formation ◽  
Power Law Distribution ◽  
Parliamentary Elections ◽  
Data Points

We study the behavior of the number of votes cast for different electoral subjects in majority elections, and in particular, the Albanian elections of the last 10 years, as well as the British, Russian, and Canadian elections. We report the frequency of obtaining a certain percentage (fraction) of votes versus this fraction for the parliamentary elections. In the distribution of votes cast in majority elections we identify two regimes. In the low percentiles we see a power law distribution, with exponent about -1.7. In the power law regime we find over 80% of the data points, while they relate to 20% of the votes cast. Votes of the small electoral subjects are found in this regime. The other regime includes percentiles above 20%, and has Gaussian distribution. It corresponds to large electoral subjects. A similar pattern is observed in other first past the post (FPP) elections, such as British and Canadian, but here the Gaussian is reduced to an exponential. Finally we show that this distribution can not be reproduced by a modified "word of mouth" model of opinion formation. This behavior can be reproduced by a model that comprises different number of zealots, as well as different campaign strengths for different electoral subjects, in presence of preferential attachment of voters to candidates.

Relocation does not have a significant effect on the growth rate of Bos indicus cross steers

2008 ◽  
Vol 48 (5) ◽  
pp. 608 ◽  
Author(s):  
R. G. Holroyd ◽  
V. J. Doogan ◽  
M. R. Jeffery ◽  
J. A. Lindsay ◽  
B. K. Venus ◽  
...  
Keyword(s):  
Growth Rate ◽  
Phase 1 ◽  
Bos Indicus ◽  
Poor Performance ◽  
The Other ◽  
Control Group ◽  
Phase 2 ◽  
Treatment Groups ◽  
Normal Ranges ◽  
Native Pastures

This experiment tested the hypothesis that relocating cattle is detrimental to their growth. The study examined the effect of having relocated cattle mixed with, or segregated from, the local acclimatised cattle at the destination property. Bos indicus cross steers (120) were allocated to three groups and were relocated, in two separate cohorts, 980 km from northern Queensland to improved pastures in central Queensland. At the start of Phase 1, the control group (C) was moved 3 months before the other two groups. The remaining two groups grazed native pastures; one group was supplemented (SR) to increase growth rate similar to that expected from improved pasture in central Queensland and the other was not supplemented (R). At the end of Phase 1, C was significantly (P < 0.05) heavier than SR, which was significantly (P < 0.05) heavier than R. At the start of Phase 2, the SR and R groups were relocated and after transportation the R and SR groups lost 12 kg or 4.4% of liveweight and 18 kg or 5.7% of liveweight, respectively; this weight loss was recovered after 5 days. All steers were reallocated to segregated (SEG) or mixed (MIX) treatment groups forming six treatments (SEG.C, SEG.R and SEG.SR and MIX.C, MIX.R and MIX.SR). There were no significant differences in liveweights within the SEG treatments by 57 days or within the MIX treatments by 106 days after relocation. There were few if any significant differences in the plasma constituents and differential leucocyte counts of the steers and most results were within physiologically normal ranges. We conclude on the basis of these results and of other experiments that the anecdotal poor performance of cattle after relocation appears to be unfounded.

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