scholarly journals A principled distance-based prior for the shape of the Weibull model

2021 ◽  
pp. 109098
Author(s):  
J. van Niekerk ◽  
H. Bakka ◽  
H. Rue
Keyword(s):  
Weibull Model

Inference for the Poly-Weibull Model

2000 ◽  
Vol 49 (2) ◽  
pp. 189-196 ◽  
Author(s):  
A. C. Davison ◽  
F. Louzada-Neto
Keyword(s):  
Weibull Model

Catastrophic Analysis of Seismic Response of Gravity Dam Sliding along Base Surface

2011 ◽  
Vol 311-313 ◽  
pp. 2164-2168
Author(s):  
Dun Ben Sun ◽  
Qing Wen Ren
Keyword(s):  
Weibull Model ◽  
Gravity Dam ◽  
Stable Region ◽  
Instability Mechanism ◽  
Gravity Dams ◽  
Base Surface ◽  
Instability Problem ◽  
Nonlinear Constitutive Model ◽  
Hysteresis Phenomena ◽  
Sliding Instability

For the instability problem of gravity dam sliding along base surface, cubic nonlinear constitutive model of soft material in base surface is adopted, which is usually expressed by Weibull model. Dynamic Equations of dam sliding along base surface is established. By means of catastrophe theory, the jumping and hysteresis phenomena of the vibration amplitude of the dam is analyzed, the parameter range of stable region in which amplitude doesn’t happen catastrophe is given and the factors which cause amplitude instability are discussed. The results obtained in the paper are of significant value for understanding the sliding instability mechanism of gravity dam under earthquake, as well as guiding the design of gravity dams.

On stochastic comparisons of k-out-of-n systems with Weibull components

2018 ◽  
Vol 55 (1) ◽  
pp. 216-232 ◽  
Author(s):  
Narayanaswamy Balakrishnan ◽  
Ghobad Barmalzan ◽  
Abedin Haidari
Keyword(s):  
Weibull Model ◽  
Exponential Model ◽  
Parallel System ◽  
Stochastic Orders ◽  
Open Problems ◽  
Increasing Convex Order ◽  
Scale Parameters ◽  
Convex Transform Order ◽  
Right Spread Order ◽  
The Right

Abstract In this paper we prove that a parallel system consisting of Weibull components with different scale parameters ages faster than a parallel system comprising Weibull components with equal scale parameters in the convex transform order when the lifetimes of components of both systems have different shape parameters satisfying some restriction. Moreover, while comparing these two systems, we show that the dispersive and the usual stochastic orders, and the right-spread order and the increasing convex order are equivalent. Further, some of the known results in the literature concerning comparisons of k-out-of-n systems in the exponential model are extended to the Weibull model. We also provide solutions to two open problems mentioned by Balakrishnan and Zhao (2013) and Zhao et al. (2016).

Earthquake Hazard Estimation in Areas of Low Historical Seismicity: A Focus on the Northern Rio Grande Rift, Colorado and New Mexico

1990 ◽  
Vol 6 (4) ◽  
pp. 657-680 ◽  
Author(s):  
Charles E. Glass
Keyword(s):  
New Mexico ◽  
Gaussian Model ◽  
Rio Grande ◽  
Earthquake Hazard ◽  
Weibull Model ◽  
Historical Seismicity ◽  
Rio Grande Rift ◽  
Earthquake Activity ◽  
Sangre De Cristo ◽  
Northern Rio Grande

Estimates of the probability of future earthquake activity are difficult to make in areas where historical seismicity may be low or absent, but where young fault scarps attest to recent or ongoing tectonism. Three non-Poisson models, a Weibull model, a Gaussian model and a lognormal model, are used to estimate the earthquake hazard for one such area, the northern Rio Grande Rift. This portion of the Rio Grande Rift displays numerous Holocene faults attesting to ongoing tectonism, but displays essentially no historical seismicity. The earthquake hazard for the Sangre de Cristo fault zone from Taos, New Mexico to Salida, Colorado calculated using these models is remarkably consistent (probability of at least one Mo = 7 earthquake in the next 50 years ∼ 2.5 × 10−3), with increased hazard for the Sangre de Cristo fault in north San Luis Valley (∼5.0×10−3) and near Taos (∼1.0×10−2) due to the long holding times along these segments.

Thermal and Starvation Stress Response of Escherichia coli O157:H7 Isolates Selected from Agricultural Environments

2016 ◽  
Vol 79 (10) ◽  
pp. 1673-1679 ◽  
Author(s):  
ACHYUT ADHIKARI ◽  
ANDY BARY ◽  
CRAIG COGGER ◽  
CALEB JAMES ◽  
GÜLHAN ÜNLÜ ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Heat Stress ◽  
Stress Response ◽  
Weibull Model ◽  
Stress Conditions ◽  
Inactivation Kinetics ◽  
Escherichia Coli O157 ◽  
Starvation Stress ◽  
E Coli ◽  
Response To Stress

ABSTRACT Pathogens exposed to agricultural production environments are subject to multiple stresses that may alter their survival under subsequent stress conditions. The objective of this study was to examine heat and starvation stress response of Escherichia coli O157:H7 strains isolated from agricultural matrices. Seven E. coli O157:H7 isolates from different agricultural matrices—soil, compost, irrigation water, and sheep manure—were selected, and two ATCC strains were used as controls. The E. coli O157:H7 isolates were exposed to heat stress (56°C in 0.1% peptone water for up to 1 h) and starvation (in phosphate-buffered saline at 37°C for 15 days), and their survival was examined. GInaFiT freeware tool was used to perform regression analyses of the surviving populations. The Weibull model was identified as the most appropriate model for response of the isolates to heat stress, whereas the biphasic survival curves during starvation were fitted using the double Weibull model, indicating the adaptation to starvation or a resistant subpopulation. The inactivation time during heating to achieve the first decimal reduction time (δ) calculated with the Weibull parameters was the highest (45 min) for a compost isolate (Comp60A) and the lowest (28 min) for ATCC strain 43895. Two of the nine isolates (ATCC 43895 and a manure isolate) had β < 1, indicating that surviving populations adapted to heat stress, and six strains demonstrated downward concavity (β > 1), indicating decreasing heat resistance over time. The ATCC strains displayed the longest δ2 (>1,250 h) in response to starvation stress, compared with from 328 to 812 h for the environmental strains. The considerable variation in inactivation kinetics of E. coli O157:H7 highlights the importance of evaluating response to stress conditions among individual strains of a specific pathogen. Environmental isolates did not exhibit more robust response to stress conditions in this study compared with ATCC strains.

scholarly journals Germination of Ocotea pulchella (Nees) Mez (Lauraceae) seeds in laboratory and natural restinga environment conditions

2009 ◽  
Vol 69 (3) ◽  
pp. 935-942 ◽  
Author(s):  
LA. Pires ◽  
VJM. Cardoso ◽  
CA. Joly ◽  
RR. Rodrigues
Keyword(s):  
Soil Moisture ◽  
Soil Moisture Content ◽  
Weibull Model ◽  
Limiting Factors ◽  
Base Temperature ◽  
Temperature Range ◽  
Optimal Temperature Range ◽  
Dry Soil ◽  
Moisture Conditions ◽  
Temperature Water

The germination response of Ocotea pulchella (Nees) Mez seeds to light, temperature, water level and pulp presence is introduced. The laboratory assays were carried out in germination chambers and thermal-gradient apparatus, whereas the field assays were performed in environments with distinct light, temperature and soil moisture conditions within a permanent parcel of Restinga forest of the Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. The seeds do not exhibit dormancy, they are non photoblastic, and a loss of viability in dry stored seeds can be related to a decrease in water content of the seed. The presence of the pulp and the flooded substratum influenced negatively the germination of O. pulchella seeds tested in the laboratory. Otherwise, light and temperature probably are not limiting factors of the germination of O. pulchella seeds in the natural environment of Restinga. The optimum temperature range for germination of Ocotea pulchella seeds was 20 to 32 ºC, the minimum or base temperature estimated was 11 ºC and the maximum ranged between 33 and 42 ºC. The isotherms exhibited a sigmoidal pattern well described by the Weibull model in the sub-optimal temperature range. The germinability of O. pulchella seeds in the understorey, both in wet and dry soil, was higher than in gaps. Germination was not affected by fluctuations in soil moisture content in the understorey environment, whereas in gaps, germination was higher in wet soils. Thus, the germination of this species involves the interaction of two or more factors and it cannot be explained by a single factor.

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