Gotowa bibliografia na temat „STEEP PROBABILITY”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Zobacz listy aktualnych artykułów, książek, rozpraw, streszczeń i innych źródeł naukowych na temat „STEEP PROBABILITY”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Artykuły w czasopismach na temat "STEEP PROBABILITY"
1
Strauch, Ronda, Erkan Istanbulluoglu, Sai Siddhartha Nudurupati, Christina Bandaragoda, Nicole M. Gasparini, and Gregory E. Tucker. "A hydroclimatological approach to predicting regional landslide probability using Landlab." Earth Surface Dynamics 6, no. 1 (2018): 49–75. http://dx.doi.org/10.5194/esurf-6-49-2018.
Pełny tekst źródłaStreszczenie:
Abstract. We develop a hydroclimatological approach to the modeling of regional shallow landslide initiation that integrates spatial and temporal dimensions of parameter uncertainty to estimate an annual probability of landslide initiation based on Monte Carlo simulations. The physically based model couples the infinite-slope stability model with a steady-state subsurface flow representation and operates in a digital elevation model. Spatially distributed gridded data for soil properties and vegetation classification are used for parameter estimation of probability distributions that characterize model input uncertainty. Hydrologic forcing to the model is through annual maximum daily recharge to subsurface flow obtained from a macroscale hydrologic model. We demonstrate the model in a steep mountainous region in northern Washington, USA, over 2700 km2. The influence of soil depth on the probability of landslide initiation is investigated through comparisons among model output produced using three different soil depth scenarios reflecting the uncertainty of soil depth and its potential long-term variability. We found elevation-dependent patterns in probability of landslide initiation that showed the stabilizing effects of forests at low elevations, an increased landslide probability with forest decline at mid-elevations (1400 to 2400 m), and soil limitation and steep topographic controls at high alpine elevations and in post-glacial landscapes. These dominant controls manifest themselves in a bimodal distribution of spatial annual landslide probability. Model testing with limited observations revealed similarly moderate model confidence for the three hazard maps, suggesting suitable use as relative hazard products. The model is available as a component in Landlab, an open-source, Python-based landscape earth systems modeling environment, and is designed to be easily reproduced utilizing HydroShare cyberinfrastructure.
2
Kwasniok, Frank. "Semiparametric maximum likelihood probability density estimation." PLOS ONE 16, no. 11 (2021): e0259111. http://dx.doi.org/10.1371/journal.pone.0259111.
Pełny tekst źródłaStreszczenie:
A comprehensive methodology for semiparametric probability density estimation is introduced and explored. The probability density is modelled by sequences of mostly regular or steep exponential families generated by flexible sets of basis functions, possibly including boundary terms. Parameters are estimated by global maximum likelihood without any roughness penalty. A statistically orthogonal formulation of the inference problem and a numerically stable and fast convex optimization algorithm for its solution are presented. Automatic model selection over the type and number of basis functions is performed with the Bayesian information criterion. The methodology can naturally be applied to densities supported on bounded, infinite or semi-infinite domains without boundary bias. Relationships to the truncated moment problem and the moment-constrained maximum entropy principle are discussed and a new theorem on the existence of solutions is contributed. The new technique compares very favourably to kernel density estimation, the diffusion estimator, finite mixture models and local likelihood density estimation across a diverse range of simulation and observation data sets. The semiparametric estimator combines a very small mean integrated squared error with a high degree of smoothness which allows for a robust and reliable detection of the modality of the probability density in terms of the number of modes and bumps.
3
Anees, M. T., K. Abdullah, M. N. M. Nawawi, N. A. N. Norulaini, M. I. Syakir, and A. K. M. Omar. "Soil erosion analysis by RUSLE and sediment yield models using remote sensing and GIS in Kelantan state, Peninsular Malaysia." Soil Research 56, no. 4 (2018): 356. http://dx.doi.org/10.1071/sr17193.
Pełny tekst źródłaStreszczenie:
The present study used pixel-based soil erosion analysis through Revised Universal Soil Loss Equation (RUSLE) and a sediment yield model. The main motive of this study is to find soil erosion probability zones and accordingly prioritise watersheds using remote sensing and Geographic Information System (GIS) techniques in Kelantan state, Peninsular Malaysia. The catchment was divided into 82 watersheds and soil loss of the catchment was calculated. Soil loss and sediment yield were divided into five categories ranging from very low to very high. Maximum area of the very high soil-loss category was observed in uncultivated land and the maximum area of very low soil-loss category was in forest. Soil erosion probability zones were also divided into five categories in which 36.1% of the area experienced zero soil erosion and 20.1% and 17.8% represented very high and high probability zones respectively. The maximum very high and high probability zones were 61.6% and 28.5% of the watershed area respectively. Prioritisation was according to the area covered by very high and high soil erosion probability zones, which showed that out of 82 watersheds, two had the very high and high priority categories respectively. The overall results indicate that high rainfall and agricultural activities enhanced the soil erosion rate on steep slopes in the catchment. Pixel-based soil erosion analysis through remote sensing and GIS was a very effective tool in finding accurate causes of soil erosion. Furthermore, it was suggested that agricultural activities and deforestation should be stopped on steep slopes because of their contribution in increasing soil erosion.
4
Zhang, Jing, Lei Wan, Yan-Ling Dong, and Li-Xin Xie. "Outcomes of different lines of keratoconus management in a tertiary eye center in north China." International Journal of Ophthalmology 15, no. 4 (2022): 568–75. http://dx.doi.org/10.18240/ijo.2022.04.07.
Pełny tekst źródłaStreszczenie:
AIM: To evaluate the treatment selections and outcomes of keratoconus and discuss the grading treatment of keratoconus. METHODS: Medical records of 1162 patients (1863 eyes) with keratoconus treated with rigid gas permeable (RGP), corneal collagen crosslinking, and keratoplasty were reviewed. The patients were grouped according to the CLEK Study. The advanced group was further divided into a <60 D group and >60 D group. The best-corrected visual acuity (BCVA) and topographic data before and after treatment were recorded. RESULTS: In the 761 eyes with steep K<52 D, nonsurgical management accounted for 83.4%, while in the 735 eyes with steep K>60 D, surgical management accounted for 90.6%. A total of 618 eyes had improved BCVA at the final follow-up point (>18mo, P<0.001). When steep K was <52 D, the BCVA in the RGP group was better than those with lamellar keratoplasty (LKP; P=0.028). When steep K was >52 D, the BCVA and topographic astigmatism outcomes showed no differences among the treatment groups. When steep K was >60 D, the BCVA in eyes treated with LKP was worse than those with steep K<60 D (P=0.025). The incidence of steep K progression in the RGP group was higher in advanced group (20.0% vs 10.8%, P=0.019). The probability of future keratoplasty in RGP was higher in advanced group (14.8% vs 7.0%, P=0.027). The incidence of steep K progression in the corneal collagen crosslinking (CXL) group was higher in advanced group (32.3% vs 8.5%, P=0.007). Multivariate logistic regression revealed the following related factors for treatment options: steep K [odds ratio (OR)=1.208, 95%CI: 1.052-1.387], TA (OR=1.171, 95%CI: 1.079-1.270), and TCT (OR=0.978, 95%CI: 0.971-0.984). The level of steep K, TA, and TCT all relates to the treatment choices of both keratoplasty and non-keratoplasty, while steep K provided the highest diagnostic accuracy (AUC=0.947, P<0.001). CONCLUSION: Steep K is an important grading treatment indicator. When steep K is <52 D, RGP lenses should be recommended. It is the best time for LKP when the steep K ranges from 52 to 60 D.
5
Tolaney, Sara M., Elizabeth Garrett-Mayer, Julia White, et al. "Updated Standardized Definitions for Efficacy End Points (STEEP) in Adjuvant Breast Cancer Clinical Trials: STEEP Version 2.0." Journal of Clinical Oncology 39, no. 24 (2021): 2720–31. http://dx.doi.org/10.1200/jco.20.03613.
Pełny tekst źródłaStreszczenie:
PURPOSE The Standardized Definitions for Efficacy End Points (STEEP) criteria, established in 2007, provide standardized definitions of adjuvant breast cancer clinical trial end points. Given the evolution of breast cancer clinical trials and improvements in outcomes, a panel of experts reviewed the STEEP criteria to determine whether modifications are needed. METHODS We conducted systematic searches of ClinicalTrials.gov for adjuvant systemic and local-regional therapy trials for breast cancer to investigate if the primary end points reported met STEEP criteria. On the basis of common STEEP deviations, we performed a series of simulations to evaluate the effect of excluding non–breast cancer deaths and new nonbreast primary cancers from the invasive disease–free survival end point. RESULTS Among 11 phase III breast cancer trials with primary efficacy end points, three had primary end points that followed STEEP criteria, four used STEEP definitions but not the corresponding end point names, and four used end points that were not included in the original STEEP manuscript. Simulation modeling demonstrated that inclusion of second nonbreast primary cancer can increase the probability of incorrect inferences, can decrease power to detect clinically relevant efficacy effects, and may mask differences in recurrence rates, especially when recurrence rates are low. CONCLUSION We recommend an additional end point, invasive breast cancer–free survival, which includes all invasive disease–free survival events except second nonbreast primary cancers. This end point should be considered for trials in which the toxicities of agents are well-known and where the risk of second primary cancer is small. Additionally, we provide end point recommendations for local therapy trials, low-risk populations, noninferiority trials, and trials incorporating patient-reported outcomes.
6
Tromans, Peter S., and Luc Vanderschuren. "A Spectral Response Surface Method for Calculating Crest Elevation Statistics." Journal of Offshore Mechanics and Arctic Engineering 126, no. 1 (2004): 51–53. http://dx.doi.org/10.1115/1.1641390.
Pełny tekst źródłaStreszczenie:
The statistics of wave crest elevation in a random, directionally spread sea are calculated using a novel approach. The nonlinearity of steep waves is modelled to second order using Sharma and Dean kinematics and a spectral response surface method is used to deduce the crest elevation corresponding to a given probability of exceedance. The spectral response surface method works in the probability domain, making it several times faster than conventional time domain simulation of random waves. However, the results from the two methods show good agreement. As expected, nonlinearity makes extreme crests higher than the corresponding linear ones.
7
Morelli, Federico Guglielmo, Michael Benzaquen, Marco Tarzia, and Jean-Philippe Bouchaud. "Confidence collapse in a multihousehold, self-reflexive DSGE model." Proceedings of the National Academy of Sciences 117, no. 17 (2020): 9244–49. http://dx.doi.org/10.1073/pnas.1912280117.
Pełny tekst źródłaStreszczenie:
We investigate a multihousehold dynamic stochastic general equilibrium (DSGE) model in which past aggregate consumption impacts the confidence, and therefore consumption propensity, of individual households. We find that such a minimal setup is extremely rich and leads to a variety of realistic output dynamics: high output with no crises; high output with increased volatility and deep, short-lived recessions; and alternation of high- and low-output states where a relatively mild drop in economic conditions can lead to a temporary confidence collapse and steep decline in economic activity. The crisis probability depends exponentially on the parameters of the model, which means that markets cannot efficiently price the associated risk premium. We conclude by stressing that within our framework, narratives become an important monetary policy tool that can help steer the economy back on track.
8
Taszarek, Mateusz, Harold E. Brooks, and Bartosz Czernecki. "Sounding-Derived Parameters Associated with Convective Hazards in Europe." Monthly Weather Review 145, no. 4 (2017): 1511–28. http://dx.doi.org/10.1175/mwr-d-16-0384.1.
Pełny tekst źródłaStreszczenie:
Abstract Observed proximity soundings from Europe are used to highlight how well environmental parameters discriminate different kind of severe thunderstorm hazards. In addition, the skill of parameters in predicting lightning and waterspouts is also tested. The research area concentrates on central and western European countries and the years 2009–15. In total, 45 677 soundings are analyzed including 169 associated with extremely severe thunderstorms, 1754 with severe thunderstorms, 8361 with nonsevere thunderstorms, and 35 393 cases with nonzero convective available potential energy (CAPE) that had no thunderstorms. Results indicate that the occurrence of lightning is mainly a function of CAPE and is more likely when the temperature of the equilibrium level drops below −10°C. The probability for large hail is maximized with high values of boundary layer moisture, steep mid- and low-level lapse rates, and high lifting condensation level. The size of hail is mainly dependent on the deep layer shear (DLS) in a moderate to high CAPE environment. The likelihood of tornadoes increases along with increasing CAPE, DLS, and 0–1-km storm-relative helicity. Severe wind events are the most common in high vertical wind shear and steep low-level lapse rates. The probability for waterspouts is maximized in weak vertical wind shear and steep low-level lapse rates. Wind shear in the 0–3-km layer is the best at distinguishing between severe and extremely severe thunderstorms producing tornadoes and convective wind gusts. A parameter WMAXSHEAR multiplying square root of 2 times CAPE (WMAX) and DLS turned out to be the best in distinguishing between nonsevere and severe thunderstorms, and for assessing the severity of convective phenomena.
9
Magnin, Florence, Bernd Etzelmüller, Sebastian Westermann, Ketil Isaksen, Paula Hilger, and Reginald L. Hermanns. "Permafrost distribution in steep rock slopes in Norway: measurements, statistical modelling and implications for geomorphological processes." Earth Surface Dynamics 7, no. 4 (2019): 1019–40. http://dx.doi.org/10.5194/esurf-7-1019-2019.
Pełny tekst źródłaStreszczenie:
Abstract. Permafrost in steep rock slopes has been increasingly studied since the early 2000s in conjunction with a growing number of rock slope failures, which likely resulted from permafrost degradation. In Norway, rock slope destabilization is a widespread phenomenon and a major source of risk for the population and infrastructure. However, a lack of precise knowledge of the permafrost distribution in steep slopes hinders the assessment of its role in these destabilizations. This study proposes the first nationwide permafrost probability map for the steep slopes of Norway (CryoWall map). It is based on a multiple linear regression model fitted with multi-annual rock surface temperature (RST) measurements, collected at 25 rock slope sites, spread across a latitudinal transect (59–69∘ N) over mainland Norway. The CryoWall map suggests that discontinuous permafrost widely occurs above 1300–1400 and 1600–1700 m a.s.l. in the north and south rock faces of southern Norway (59∘ N), respectively. This lower altitudinal limit decreases in northern Norway (70∘ N) by about 500±50 m, with a more pronounced decrease for south faces, as a result of the insolation patterns largely driven by midnight sun in summer and polar night in winter. Similarly, the mean annual RST differences between north and south faces of similar elevation range around 1.5 ∘C in northern Norway and 3.5 ∘C in southern Norway. The CryoWall map is evaluated against direct ice observations in steep slopes and discussed in the context of former permafrost studies in various types of terrain in Norway. We show that permafrost can occur at much lower elevations in steep rock slopes than in other terrains, especially in north faces. We demonstrate that the CryoWall map is a valuable basis for further investigations related to permafrost in steep slopes in terms of both practical concerns and fundamental science.
10
Gallach-Sánchez, David, Peter Troch, and Andreas Kortenhaus. "AVERAGE AND WAVE-BY-WAVE OVERTOPPING PERFORMANCE OF STEEP LOW-CRESTED STRUCTURES." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 77. http://dx.doi.org/10.9753/icce.v36.papers.77.
Pełny tekst źródłaStreszczenie:
Wave overtopping is a key process in coastal protection. The assessment of the wave overtopping rates is an important aspect in the design of coastal structures. In this paper, the focus is on steep low-crested structures, which include structures with steep slopes up to the limit case with vertical structures, with small relative freeboards up to the case with zero freeboards. This type of structures is of use for coastal protection in the case of sea level rise within climate change process and for overtopping wave energy converters. A literature review of the overtopping knowledge available for steep low-crested structures is carried out, identifying a knowledge gap. To fill this knowledge gap, 2D hydraulic model tests were performed at the wave flume of the Department of Civil Engineering at Ghent University, measuring wave conditions and the overtopping performance. Average and individual wave overtopping were analysed and compared to existing prediction formulae. Inaccuracies in the existing prediction formulae are detected and studied, and enhanced prediction formulae are presented for the average overtopping and the probability distribution of the individual overtopping volumes. The new prediction formulae improve the accuracy of wave overtopping volumes for steep low-crested structures range while maintaining the accuracy for other types of structures. The improved understanding of the overtopping behaviour allows a safer design of coastal structures.
Rozprawy doktorskie na temat "STEEP PROBABILITY"
1
Seyedali, Seyed Mohamad. "Getting a Grip on Scrap : Applying Probability and Statistics in Analyzing Scrap and Steel Composition Data from Electrical Steel Production." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-165413.
Pełny tekst źródłaStreszczenie:
This study intends to better control the final composition of steel by trying to have a better knowledge of elements including copper, nickel, molybdenum, manganese, tin and chromium in the scrap. This objective was approached by applying probability and statistical concepts such as normal distribution, multiple linear regression and least square and non-negative least square concepts. The study was performed on the raw materials’ information of Ovako Smedjebacken and Ovako Hofors, two steel production plants in Sweden. The information included but were not limited to the amount of the different scrap types used in the charge, total weight of the charge and the final composition of the produced steel. First, the concept of normal distribution was used as to consider the variations of the alloying elements between the estimated and measured alloy contents. The data were then used to consider a model for distribution factor of the studied elements. Also, an estimation of the alloy contents in the scrap type given the final steel composition was carried out using the concept of probability and statistics. At the end, a comparison of the results from the different concepts was done.
2
Reynolds, James Bernard. "Advanced analysis and reliability-based design of steel scaffolding systems." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11626.
Pełny tekst źródłaStreszczenie:
This thesis presents a comprehensive investigation of the advanced analysis, reliability-based design and optimisation of steel support scaffolding systems. Support scaffolding systems are used to provide temporary support to timber formwork systems, reinforcement, concrete, workmen and equipment, during the construction of permanent structures such as buildings and bridges. Stick-type steel scaffolds with cuplok joints are the focus of the thesis. This thesis includes the collection and statistical analysis of shore load effects occurring as a result of construction dead and live loads. A comprehensive series of U-head joint subassembly tests, allowed the top rotational stiffness to be rationally quantified for advanced finite element modelling. Advanced finite element models are calibrated using data compiled in a previous investigation involving eighteen full-scale tests. This calibration exercise also provides statistical data for modelling error. Monte Carlo simulations using advanced analysis are performed to determine the statistical distributions of system strength for a range of geometric configurations of support scaffold systems. The research showed that system strength was governed mainly by jack extension at the top and bottom of the scaffolding system. By incorporating the load statistics and system strength statistics, the thesis determined the reliability of various steel scaffolding systems designed by the fundamental Load-Resistance-Factor-Design (LRFD) equation. The study further proposed a more efficient LRFD equation for steel scaffolding, based on an acceptable target reliability index.
3
Salgar, Chaparro Silvia Juliana. "Understanding of Microbiologically Influenced Corrosion in Carbon Steel Pipelines: Towards Developing a Methodology to Assess Probability of Failure." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/81959.
Pełny tekst źródłaStreszczenie:
This dissertation evaluated critical aspects of microbiologically influenced corrosion (MIC) and generated valuable information for the understanding and management of this corrosion threat. The main outcomes include a better understanding of the preservation requirements for field samples to obtain accurate results; an innovative approach for MIC assessment that consists of the identification of total and active microbial communities; knowledge of the effect that environmental and operational conditions can have on microbial communities and MIC.
4
Chatterjee, Aritra. "Structural System Reliability with Application to Light Steel-Framed Buildings." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/74879.
Pełny tekst źródłaStreszczenie:
A general framework to design structural systems for a system-reliability goal is proposed.
Component-based structural design proceeds on a member to member basis, insuring acceptable failure probabilities for every single structural member without explicitly assessing
the overall system safety, whereas structural failure consequences are related to the whole
system performance (the cost of a building or a bridge destroyed by an earthquake) rather
than a single beam or column failure. Engineering intuition tells us that the system is
safer than each individual component due to the likelihood of load redistribution and al-
ternate load paths, however such conservatism cannot be guaranteed without an explicit
system-level safety check. As a result, component-based structural designs can lead to both
over-conservative components and a less-than-anticipated system reliability.
System performance depends on component properties as well as the load-sharing network,
which can possess a wide range of behaviors varying from a dense redundant system with
scope for load redistribution after failure initiates, to a weakest-link type network that fails as
soon as the first member exceeds its capacity. The load-sharing network is characterized by
its overall system reliability and the system-reliability sensitivity, which quantifies the change in system safety due to component reliability modifications. A general algorithm is proposed
to calculate modified component reliabilities using the sensitivity vector for the load-sharing
network. The modifications represent an improvement on the structural properties of more
critical components (more capacity, better ductility), and provide savings on less important
members which do not play a significant role.
The general methodology is applied to light steel-framed buildings under seismic loads.
The building is modeled with non-linear spring elements representing its subsystems. The
stochastic response of this model under seismic ground motions provides load-sharing, system
reliability and sensitivity information, which are used to propose target diaphragm and shear
wall reliability to meet a building reliability goal. Finally, diaphragm target reliability is
used to propose modified component designs using stochastic simulations on geometric and
materially non-linear finite-element models including every individual component.<br>Ph. D.
5
Bonneric, Matthieu. "Etude de l'endommagement en fatigue de câbles d'acier sous sollicitations complexes." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC045.
Pełny tekst źródłaStreszczenie:
Les câbles d’acier sont utilisés comme renforts au sein des pneumatiques poids lourds, et servent notamment à supporter les efforts dus à la pression de gonflage et au poids du véhicule. Un câble est un ensemble de fils d’acier perlitique assemblés en hélices sur différentes couches. Il existe donc de nombreuses possibilités d’assemblage pour définir l’architecture d’un câble. Lors de leur sollicitation en service, les câbles sont soumis à des chargements cycliques à l’origine d’un endommagement en fatigue. Dans un contexte de réduction de la consommation et d’allègement des véhicules, la compréhension des mécanismes impliqués représente donc un enjeu majeur pour les manufacturiers de pneumatiques, en vue d’optimiser l’architecture des câbles vis-à-vis de la tenue en fatigue. Un essai de flexion cyclique représentatif de la sollicitation en service a été mis au point. Les éprouvettes testées sont des nappes composites constituées de câbles alignés au sein d’une matrice de gomme. Des essais interrompus à différents stades de l’endommagement suivis d’observations ex-situ (tomographie à rayon X, MEB) ont été réalisés. Un modèle de simulation par éléments finis de la nappe composite a été développé en vue d’étudier les interactions filgomme. La comparaison des observations aux simulations a permis de comprendre la cinétique de l’endommagement des renforts lors d’une sollicitation de flexion cyclique.L’étude de chacun des mécanismes susceptibles de contribuer à l’endommagement d’un câble a permis d’expliquer la meilleure tenue en fatigue des architectures pénétrées par la gomme. Un outil probabiliste de prédiction de la durée de vie des câbles basé sur la propagation des défauts en surface des fils a été développé<br>Steel cables are used as reinforcements in heavy truck tires, in particular to support the forces resulting from the tire pressure and the vehicle's weight. A cable is a set of pearlitic steel wires assembled in helical form on different layers. There are therefore many assembly possibilities to define the cable architecture. The cables are subjected to cyclic loadings during service, resulting in fatigue damage. In a context of reduced fuel consumption and lighter vehicles, understanding the mechanisms involved is thus a major challenge for tire manufacturers, in order to optimize the architecture of cables with respect to fatigue resistance. A cyclic bending test representative of mechanical in-service loading has been developed. The tested specimens are composite layers made of cables aligned within an elastomer matrix. Interrupted tests at different stages of damage followed by ex-situ observations (X-ray tomography, SEM) were performed. A finite element model of the composite layer has been developed in order to understand wire-rubber interactions. The comparison of the observations with the simulations made it possible to understand the kinetics of cable damage during cyclic bending loading.The study of each of the mechanisms likely to contribute to the cable damage has made it possible to explain the better fatigue resistance of the architectures penetrated by the rubber. A stochastic cable fatigue life model based on wire surface defect propagation has been developed
6
Rota, Bernardo João. "Calibration Adjustment for Nonresponse in Sample Surveys." Doctoral thesis, Örebro universitet, Handelshögskolan vid Örebro Universitet, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-51966.
Pełny tekst źródłaStreszczenie:
In this thesis, we discuss calibration estimation in the presence of nonresponse with a focus on the linear calibration estimator and the propensity calibration estimator, along with the use of different levels of auxiliary information, that is, sample and population levels. This is a fourpapers- based thesis, two of which discuss estimation in two steps. The two-step-type estimator here suggested is an improved compromise of both the linear calibration and the propensity calibration estimators mentioned above. Assuming that the functional form of the response model is known, it is estimated in the first step using calibration approach. In the second step the linear calibration estimator is constructed replacing the design weights by products of these with the inverse of the estimated response probabilities in the first step. The first step of estimation uses sample level of auxiliary information and we demonstrate that this results in more efficient estimated response probabilities than using population-level as earlier suggested. The variance expression for the two-step estimator is derived and an estimator of this is suggested. Two other papers address the use of auxiliary variables in estimation. One of which introduces the use of principal components theory in the calibration for nonresponse adjustment and suggests a selection of components using a theory of canonical correlation. Principal components are used as a mean to accounting the problem of estimation in presence of large sets of candidate auxiliary variables. In addition to the use of auxiliary variables, the last paper also discusses the use of explicit models representing the true response behavior. Usually simple models such as logistic, probit, linear or log-linear are used for this purpose. However, given a possible complexity on the structure of the true response probability, it may raise a question whether these simple models are effective. We use an example of telephone-based survey data collection process and demonstrate that the logistic model is generally not appropriate.
7
Zarov, Filipp. "Modeling fault probability in single railroad turnouts in Eastern Region, Sweden, with the use of logistic regression models : A step from preventive to predictive preventive maintenance in railway maintenance planning." Thesis, KTH, Transportplanering, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-273639.
Pełny tekst źródłaStreszczenie:
Turnouts are an important part of railway infrastructure for two reasons: infrastructure andmaintenance. For the infrastructure they provide the flexibility to allow the formulation and branchingof railway network and for maintenance they consume a large part of maintenance budget and have aprominent place in maintenance planning policy and activities. This is because as a “mechanical object”,a turnout often experiences malfunctions. The problem becomes even more complicated, since a turnoutis composed of many different parts and each of them fails for very different reasons (e.g. switch bladesvs crossing part). This is reflected in the different needs for maintenance activities, as railways areforced to pour in excessive amounts of resources to carry out emergency repairs, or to carry outunnecessary scheduled maintenance works in turnouts, which do not need to be inspected or repaired.Therefore, it is difficult to plan and organize maintenance activities in turnouts in an efficient manner.This raises the question of whether malfunctions in turnouts can be predicted and used as informationfor the maintenance planning process in order to optimize it and develop it into a more reliablepreventive maintenance planning.The aim of this analysis is to attempt to model the probability of various malfunctions in turnouts asa function of their main geometric and operational characteristics by using logistic regression modelsand then input these results into the maintenance planning process in order to optimize it. First, it wasimportant to objectify the railway track system and the turnout components, both in terms of parts andinterrelationships. Furthermore, the process and basic elements of railway maintenance planning weredefined, as well as arguments that motivate a turn towards preventive maintenance planningmethodologies. This was done through a comprehensive literature study.The basis of this research was case studies, which described the relationship between geometricaland operational characteristics of turnouts and their wear, as well as risk-based modelling methods inrailway maintenance planning. To create the analysis model, data from turnouts in eastern regionprovided by the Swedish Transport Administration were used, both from the point of view of describingthe underlying causes of turnout malfunctions and to formulate an object-oriented database suitable forusing in logistic regression models. The goal was a logit model that calculated the malfunctionprobability of a turnout, which could be used directly into a maintenance planning framework, whichranked maintenance activities in turnouts.The results obtained showed that although the model suffers from low correlation, differentrelationships between input variables and different functional errors were established. Furthermore, thepotential of these analytical models and modeling structures was shown to be able to developpreventive, predictive railway maintenance plans, but further analysis of the data structure is required,especially regarding data quality. Finally, further possible research areas are presented.<br>Spårväxlar är viktiga delar av järnvägens infrastruktur av två orsaker: infrastruktur och underhåll.För infrastrukturen ger de möjlighet till flexibla tillåter de formulering och grenning av järnvägsnät ochför underhållet konsumerar de en stor del av underhållsbudgeten och de har en framträdande plats iunderhållsplaneringspolitiken och aktiviteterna. Detta beror på att som ett ”maskinellt objekt”, harspårväxeln ofta fel. Problemet blir ännu mer komplicerat, eftersom en spårväxel består av många olikadelar och var och en av dem bryts ner av mycket olika skäl (t.ex. tunganordning vs korsningsdel). Dettaåterspeglas i olika behov av underhållsaktiviteter. Eftersom järnvägarna tvingas hålla alltför storamängder resurser för att utföra akuta reparationer eller för att utföra onödiga schemalagdaunderhållsarbeten i spårväxlar, som inte behöver inspekteras eller repareras. Därför är det svårt attplanera och organisera underhållsaktiviteter för spårväxlarna på ett effektivt sätt. Detta ställer fråganom funktionsfel i spårväxlar kan förutsägas och användas som information till underhållsplaneringsprocessen för att optimera den och utveckla den till en pålitligare förebyggandeunderhållsplanering.Syftet med denna analys är att försöka modellera sannolikheten för olika funktionsfel i spårväxlarsom en funktion av deras huvudsakliga geometriska och operativa egenskaper med användning avlogistiska regressionsmodeller och sedan mata dessa resultat in i underhållsplaneringsprocessen för attoptimera den. För det första var det viktigt att objektifiera järnvägsspårsystemet ochspårväxlarkomponenterna, både vad gäller delar och inbördes förhållanden. Dessutom definieradesprocessen och grundelementen i järnvägsunderhållsplaneringen, samt att argument som motiverarförändring till förebyggande underhållsplaneringsmetoder. Detta gjordes genom en omfattandelitteraturstudie.Grunden i denna analys var fallstudier, som beskrev förhållandet mellan geometriska ochoperationella egenskaper hos spårväxlar och deras förslitning samt riskbaserade modelleringsmetoder ijärnvägsunderhållsplanering. För att skapa analysmodellen användes data från spårväxlar i östraregionen som tillhandahölls av Trafikverket, både ur synpunkten att beskriva de underliggandeorsakerna till spårväxlarsfel och för att formulera en objektorienterad databas lämplig för användning ilogistiska regressionsmodeller. Målet var en logitmodell som beräknade sannolikheten för fel i enspårväxel, som kunde användas direkt i en underhållsplaneringsram, som rangordnar lämpigaunderhållsaktiviteter i spårväxlar.Erhållna resultat visade att även om modellen lider av låg korrelation, konstaterades olika sambandmellan ingående variabler och olika funktionsfel. Vidare visades potentialen hos dessa analysmodelleroch modelleringsstrukturer för att kunna utveckla förebyggande, förutsägbarajärnvägsunderhållsplaner, men det krävs troligtvis ytterligare analys av datastrukturen, specielltangående datakvaliteten. Slutligen presenteras ytterligare möjliga forskningsområden.
8
Alves, Clever Gama. "Analise de confiabilidade em fadiga : estudo de caso : braço de controle de suspensão automotiva." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264943.
Pełny tekst źródłaStreszczenie:
Orientador: Itamar Ferreira<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica<br>Made available in DSpace on 2018-08-11T17:15:29Z (GMT). No. of bitstreams: 1
Alves_CleverGama_M.pdf: 6160446 bytes, checksum: 5afa2cd3848388247de70ceee21a3cf8 (MD5)
Previous issue date: 2008<br>Resumo: O presente trabalho descreve um procedimento de aprovação de um braço de controle de suspensão automotiva sujeito a fadiga de alto ciclo, ao mesmo tempo em que propõe uma sistemática alternativa de validação baseada em conceitos e teorias estatísticas de confiabilidade. Nesse aspecto, a pesquisa não só avalia o procedimento seguido pelo fabricante, como também executa comparações gráfico-analíticas de distribuições probabilísticas (normal, lognormal e Weibull) a fim de caracterizar a massa de dados completos e suspensos obtidos em ensaios acelerados de bancada. Um espaço amostral constituído por quatro observações completas da configuração final da peça e oito da inicial, complementado por doze dados suspensos, foi usado para determinar os parâmetros dos modelos. Essa análise levou à escolha do modelo de Weibull bi-paramétrico para o tempo até a falha para as duas configurações em foco. A estimação final dos parâmetros foi feita pelo método da máxima verossimilhança, o qual superou um método alternativo específico para Weibull na comparação com a distribuição referencial de categoria. Dessa forma, calculou-se o ganho efetivo em confiabilidade conseguido com o esforço adicional de desenvolvimento da peça. O teste de hipóteses de Kruskal-Wallis permitiu concluir que as duas configurações realmente possuem performances de durabilidade diferentes. É notável o ganho em confiabilidade obtido por meio das mudanças que levaram à configuração final: em um universo de um milhão de peças, o número de falhas esperadas aos 30.000 ciclos caiu de 96.384 para 5 partes por milhão<br>Abstract: This dissertation aims at describing a procedure for approval of a suspension control arm subjected to high-cycle fatigue and, simultaneously, at proposing a validation alternative method based on reliability concepts and statistical theories. In that manner, the research provides not only an assessment of the procedure followed by the manufacturer, but also analytical and graphical comparisons of probabilistic distributions (normal, lognormal, Weibull) in order to characterize the set of complete and suspended data from bench accelerated tests. A sample space comprised by four complete final configuration observations and eight complete primary
configuration ones, in addition to twelve suspended figures, was the basis for determining the model parameters. Such an analysis led to choose the bi-parametric Weibull for both focused configurations¿ time to failure. The ultimate estimation of the parameters was performed through the maximum likelihood method, which beat a specific alternative method for Weibull when compared with the referential category distribution. Thus, the effective gain in reliability resulting from the product development additional effort was calculated. The Kruskal-Wallis hypothesis testing guided the conclusion that the two configurations actually have different durability performances. It is impressive the gain in reliability brought by the changes that led towards the final configuration: taking an amount of one million parts into consideration, the expected number of failures at 30,000 cycles dropped from 96,384 to 5 parts per million<br>Mestrado<br>Materiais e Processos de Fabricação<br>Mestre em Engenharia Mecânica
9
Fox, Clayton D. L. "Modeling Simplified Reaction Mechanisms using Continuous Thermodynamics for Hydrocarbon Fuels." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37554.
Pełny tekst źródłaStreszczenie:
Commercial fuels are mixtures with large numbers of components. Continuous thermodynamics is a technique for modelling fuel mixtures using a probability density function rather than dealing with each discreet component. The mean and standard deviation of the distribution are then used to model the chemical reactions of the mixture. This thesis develops the necessary theory to apply the technique of continuous thermodynamics to the oxidation reactions of hydrocarbon fuels. The theory is applied to three simplified models of hydrocarbon oxidation: a global one-step reaction, a two-step reaction with CO as the intermediate product, and the four-step reaction of Müller et al. (1992), which contains a high- and a low-temperature branch. These are all greatly simplified models of the complex reaction kinetics of hydrocarbons, and in this thesis they are applied specifically to n-paraffin hydrocarbons in the range from n-heptane to n-hexadecane. The model is tested numerically using a simple constant pressure homogeneous ignition problem using Cantera and compared to simplified and detailed mechanisms for n-heptane. The continuous thermodynamics models are able not only to predict ignition delay times and the development of temperature and species concentrations with time, but also changes in the mixture composition as reaction proceeds as represented by the mean and standard deviation of the distribution function. Continuous thermodynamics is therefore shown to be a useful tool for reactions of multicomponent mixtures, and an alternative to the "surrogate fuel" approach often used at present.
10
Guerchais, Raphaël. "Influence d'accidents géométriques et du mode de chargement sur le comportement en fatigue à grand nombre de cycles d'un acier inoxydable austénitique 316L." Thesis, Paris, ENSAM, 2014. http://www.theses.fr/2014ENAM0020/document.
Pełny tekst źródłaStreszczenie:
L'objectif de ces travaux de thèse est d'étudier l'influence de la microstructure et de défauts géométriques sur le comportement en fatigue à grand nombre de cycles (FGNC) d'un acier inoxydable austénitique 316L. La méthodologie proposée s'appuie sur des simulations par éléments finis (EF) d'agrégats polycristallins qui permettent de décrire les champs mécaniques à l'échelle des mécanismes impliqués dans les processus d'amorçage de fissures de fatigue.Une étude numérique préliminaire, s'appuyant sur des données expérimentales issues de la littérature, est conduite sur un cuivre électrolytique à l'aide de simulations numériques d'agrégats polycristallins en 2D. L'effet du trajet de chargement et de défauts artificiels de taille proche ou légèrement supérieure à celle de la microstructure sur les réponses mécaniques mésoscopiques sont analysés. Les capacités de prédiction de quelques critères de fatigue, s'appuyant sur des quantités mécaniques mésoscopiques, sont évaluées. Il est mis en évidence que les limites de fatigue macroscopiques prédites par un critère de fatigue probabiliste sont en accord avec les tendances expérimentales observées en fatigue multiaxiale et en présence de défauts.Une campagne expérimentale a été menée sur un acier austénitique 316L. Des essais de fatigue oligocyclique sont conduits afin de caractériser le comportement élasto-plastique du matériau. Des essais de FGNC, utilisant des éprouvettes avec et sans défaut de surface (défaut artificiel hémisphérique) ont été effectués pour estimer les limites de fatigue dans différentes conditions de sollicitation (traction, torsion, traction et torsion combinée, traction biaxiale) et pour plusieurs rayons de défaut. Dans le but de compléter la caractérisation du matériau, la microstructure est étudiée à l'aide d'analyses EBSD et la texture cristallographique est mesurée par diffraction des rayons X. Ces résultats expérimentaux sont utilisés pour reproduire, avec des simulations EF, les essais de FGNC sur des microstructures 2D et 3D représentatives de l'acier austénitique. L'hétérogénéité de quantités mécaniques mésoscopiques pertinentes en fatigue est discutée avec une attention particulière sur l'effet des défauts. L'approche probabiliste est appliquée aux résultats des modèles EF pour quantifier l'effet de la taille du défaut, pour différents trajets de chargement. La pertinence, vis-à-vis des observations expérimentales, des distributions de la limite de fatigue prédites est évaluée<br>The aim of this study is to analyze the influence of both the microstructure and defects on the high cycle fatigue (HCF) behaviour of a 316L austenitic stainless steel thanks to finite element (FE) simulations of polycrystalline aggregates.%The scatter encountered in the HCF behavior of metallic materials is often explained by the anisotropic elasto-plastic behavior of individual grains leading to a highly heterogeneous distribution of plastic slip.Since fatigue crack initiation is a local phenomenon, intimately related to the plastic activity at the crystal scale, it seems relevant to rely on this kind of modeling to evaluate the mechanical quantities.A preliminary numerical study, based on experimental data drawn from the litterature, was conducted on an electrolytic copper using simulations of 2D polycrystalline aggregates. The effect of the loading path and small artificial defects on the mesoscopic mechanical responses have been analyzed separately. Moreover, the predictive capabilities of some fatigue criteria, relying on the mesoscopic mechanical responses, has been evaluated. It was shown that the macroscopic fatigue limits predicted by a probabilistic fatigue criterion are in accordance with the experimental trends observed in multiaxial fatigue or in the presence of small defects.An experimental campaign is undertaken on an austenitic steel 316L. Low cycle fatigue tests are conducted in order to characterize the elasto-plastic behavior of the material. Load-controled HCF tests, using both smooth specimens and specimens containing an artificial hemispherical surface defect, are carried out to estimate the fatigue limits under various loading conditions (tension, torsion, combined tension and torsion, biaxial tension) and several defect radii. To complete the characterization of the material, the microstructure is studied thanks to EBSD analyzes and the cristallographic texture is measured by X-ray diffraction. These experimental data are used to reproduce, with FE simulations, the HCF tests on 2D and 3D microstructures representative of the austenitic steel. The heterogeneity of the mesoscopic mechanical quantities relevant in fatigue are discussed in relation to the modeling. The results from the FE models are then used along with the probabilistic mesomechanics approach to quantify the defect size effect for several loading paths. The relevance, with respect to the experimental observations, of the predicted fatigue strength distributions is assessed
Książki na temat "STEEP PROBABILITY"
1
Ronchetti, Elvezio. Step 1: Statistique et probabilités : une introduction. 2nd ed. Presses polytechniques et universitaires romandes, 1991.
Znajdź pełny tekst źródła
2
Fowler, C. W. Constructing species frequency distributions: A step toward systemic management. U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center, 1999.
Znajdź pełny tekst źródła
3
M, Kerry Sally, ed. Presenting medical statistics: From proposal to publication : a step-by-step guide. Oxford University Press, 2007.
Znajdź pełny tekst źródła
4
Diamantopoulos, Adamantios. Taking the fear out of data analysis: A step-by-step approach. Thomson Learning, 2000.
Znajdź pełny tekst źródła
5
Diamantopoulos, Adamantios. Taking the fear out of data analysis: A step-by-step approach. Business Press, 2000.
Znajdź pełny tekst źródła
6
Pallant, Julie. SPSS survival manual: A step by step guide to data analysis using SPSS for WIndows (versions 10 and 11). Open University Press, 2001.
Znajdź pełny tekst źródła
7
Ma, Jin. Forward-backward stochastic differential equations and their applications. Springer, 1999.
Znajdź pełny tekst źródła
8
Saha, Prasenjit, and Paul A. Taylor. Nuclear Fusion in Stars. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198816461.003.0006.
Pełny tekst źródłaStreszczenie:
This chapter enumerates some of the many nuclear reactions in stars. It focuses on a general principle: nuclear fusion requires overcoming the Coulomb barrier between nuclei, which is possible through the relatively infrequent process of quantum tunnelling. The tunnelling probability depends on the atomic num-bers and mass numbers of the nuclei involved, and also on their relative speed. These translate into steep and interesting temperature dependencies for nuclear reactions. Analytic approximations yield a rate that is almost vanishingly rare, yet within the incredibly large number of potential interactions within stars quantum tunnelling can still provide the underlying ignition of nuclear reactions.
9
Rosman, Beckie. Learn Probability : Step-By-Step Solutions for 100 Probability Questions: Basic Probability Concepts. Independently Published, 2021.
Znajdź pełny tekst źródła
10
Publishing, School Specialty. Step-By-Step Probability, Intermediate. Instructional Fair, 2003.
Znajdź pełny tekst źródłaCzęści książek na temat "STEEP PROBABILITY"
1
Dacunha-Castelle, Didier, and Marie Duflo. "Step by Step Decisions." In Probability and Statistics. Springer New York, 1986. http://dx.doi.org/10.1007/978-1-4612-4870-5_6.
Pełny tekst źródła
2
Bizjak, Aleš, and Lars Birkedal. "Step-Indexed Logical Relations for Probability." In Lecture Notes in Computer Science. Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-46678-0_18.
Pełny tekst źródła
3
Shi, T., and Y. Wang. "Probability model of flexural capacity of corroded steel beam." In Advances in Maritime Technology and Engineering. CRC Press, 2024. http://dx.doi.org/10.1201/9781003508762-59.
Pełny tekst źródła
4
Golić, Jovan Dj, and Renato Menicocci. "Edit Probability Correlation Attack on the Alternating Step Generator." In Sequences and their Applications. Springer London, 1999. http://dx.doi.org/10.1007/978-1-4471-0551-0_15.
Pełny tekst źródła
5
Knight, F. B. "Poisson representation of strict regular step filtrations." In Séminaire de Probabilités XX 1984/85. Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/bfb0075706.
Pełny tekst źródła
6
Marden, John I., and Michael D. Perlman. "On the Inadmissibility of the Modified Step-Down Test Based on Fisher’s Method For Combining Independentp-Values." In Contributions to Probability and Statistics. Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4612-3678-8_34.
Pełny tekst źródła
7
Zhang, Lifeng, and Ying Ren. "Attachment Probability of an Inclusion on a Bubble in Molten Steel." In Handbook of Non-Metallic Inclusions in Steels. Springer Nature Singapore, 2025. https://doi.org/10.1007/978-981-97-9638-0_21.
Pełny tekst źródła
8
Marwitz, Florian Andreas, Tanya Braun, and Ralf Möller. "A First Step Towards Even More Sparse Encodings of Probability Distributions." In Inductive Logic Programming. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-97454-1_13.
Pełny tekst źródła
9
Walrand, Jean. "Route Planning: A." In Probability in Electrical Engineering and Computer Science. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-49995-2_13.
Pełny tekst źródłaStreszczenie:
AbstractThis chapter is concerned with making successive decisions in the presence of uncertainty. The decisions affect the cost at each step but also the “state” of the system. We start with a simple example: choosing a route with uncertain travel times. We then examine a more general model: controlling a Markov chain.Section 13.1 presents a model of route section when the travel times are random. Section 13.2 shows one formulation where one plans the trip long in advance. Section 13.3 explains how the problem changes if one is able to adjust the route based on real-time information. That section introduces the main ideas of stochastic dynamic programming. Section 13.4 discusses a generalization of the route planning problem: a Markov decision problem. Section 13.5 solves the problem when the horizon is infinite.
10
Checchi, Daniele, and Tindaro Cicero. "Is Entering Italian Academia Getting Harder?" In Teaching, Research and Academic Careers. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-07438-7_5.
Pełny tekst źródłaStreszczenie:
AbstractWhile a PhD degree is often considered the first necessary step to an academic career, since 2010 only a small fraction (less than 10%) of doctoral graduates obtained a position in academia within six years of the award of their degree. While we do not have information on their labour market outcomes, we can examine the determinants of this transition in order to study whether entry to an academic job is becoming more difficult. We merge three national administrative data archives covering completed doctoral degrees, postdoc collaborations and new hirings to academia (mostly assistant professor level). We find a decline in appointment probability after 2010, due to the hiring freeze imposed by fiscal austerity. We find, also, that a PhD degree and postdoc experience have a positive effect on the probability of obtaining a position in academia, while being a woman or being a foreign-born candidate has a negative effect. We found no evidence of career disadvantages for candidates from Southern universities.
Streszczenia konferencji na temat "STEEP PROBABILITY"
1
Zapp, Philip E., and Thomas B. Edwards. "Statistical Analysis of Inhibitor Concentrations for Radioactive Waste in Carbon Steel Tanks." In CORROSION 1994. NACE International, 1994. https://doi.org/10.5006/c1994-94116.
Pełny tekst źródłaStreszczenie:
Abstract Based on a logistic regression approach, a model was developed using the explanatory variables log([NO3-]), log([NO2-]), and temperature to estimate the probability of pitting in a carbon steel exposed to high-level radioactive waste. Pitting susceptibility data obtained by the two techniques of cyclic potentiodynamic polarization and coupon immersion were separately and jointly analyzed with the model. Similar predictive ability is seen for equations based on both electrochemical and coupon immersion data. Using the theory associated with the determination of confidence intervals for the estimated probability, a methodology was developed to provide a lower bound for the nitrite concentration which inhibits pitting, i. e., which holds the estimated probability of pitting to a reasonably low level of 0.05.
2
Cardoso, Juliana Lopes, Rafael Ribeiro Urano Alves, Mayara Stecanella Pacheco, and Zehbour Panossian. "Study of the Galvanic Potential of Zinc and Steel to Elucidate Galvanized Steel and Dual-Coated (Zinc/Epoxy) Rebar Potentials in Concrete Structures." In CORROSION 2019. NACE International, 2019. https://doi.org/10.5006/c2019-13336.
Pełny tekst źródłaStreszczenie:
Abstract The monitoring of the open circuit potential of the reinforcement is used to identify regions in concrete structures with active processes of corrosion. For carbon steel rebars, ASTM* C876 (2015) standard provides the correlation between the numerical value of the potentials measured and the steel rebar condition, defining a range with a greater than 90 % probability of occurrence of corrosion, or a greater than 90 % probability of not being corroded and, between these, an uncertain corrosion condition. However, the potential values established for carbon steel rebars are not applicable for galvanized steel rebars because the zinc and the steel form a galvanic couple and the value of the open circuit potential is a function of the exposed area ratio of the zinc and the steel. In order to verify and suggest a classification similar to that of the carbon steel rebars for galvanized steel rebars, the open circuit potential of the galvanic couple of zinc/steel was measured considering various area ratios, in simulated pore solutions with and without chloride ion contamination. The obtained potential values were compared to the potential of galvanized and dual-coated (zinc/epoxy) rebars, embedded in concrete.
3
Bilkova, K., N. Hackerman, and M. Bartos. "Inhibition of CO2 Corrosion of Carbon Steel by Thioglycolic Acid." In CORROSION 2002. NACE International, 2002. https://doi.org/10.5006/c2002-02284.
Pełny tekst źródłaStreszczenie:
Abstract Corrosion inhibition of mild steel in aqueous salt environments containing CO2 by thioglycolic acid (TGA) was studied using various electrochemical and analytical techniques. The inhibitor performance and its inhibition efficiency at various concentrations and the effect of exposure time and pH of the solution were evaluated. The proposed mechanism of inhibition by TGA considers the complexity of experimental data obtained by various techniques. This mechanism is discussed in terms of adsorption, protective film formation, and especially pH effect and the chemistry of the solution. The probability of local attack caused by TGA is also taken into consideration.
4
Hoffman, Elizabeth N., Philip E. Zapp, Bruce J. Wiersma, and Thomas B. Edwards. "Probability-Based Corrosion Control for High Level Waste Tanks." In CORROSION 2010. NACE International, 2010. https://doi.org/10.5006/c2010-10231.
Pełny tekst źródłaStreszczenie:
Abstract Controls on the solution chemistry are in place to prevent the initiation and propagation of pitting and stress corrosion cracking in high level waste (HLW) tanks. These controls are based upon a series of experiments performed using solutions that simulate waste tank conditions on materials used for construction of the tanks, namely ASTM A537 carbon steel (A537). An experimental program was undertaken to investigate the risk associated with reducing the minimum nitrite concentration required to confidently inhibit pitting in dilute solutions. Electrochemical and coupon testing were performed within the framework of the statistical test matrix to determine the pitting propensity associated with inhibitor concentrations. A mixture/amount model has been identified as a valid model based on statistical analysis of recent and historically collected electrochemical data; the model divides the nitrate/nitrite concentration space into regions of probable and unlikely pitting. Understanding the probability for pitting will allow the facility to make tank-specific risk-based decisions for chemistry control.
5
Sagüés, Alberto, and Joseph Fernandez. "Modeling Nuclear Containment Liner Steel Liner Corrosion." In CORROSION 2013. NACE International, 2013. https://doi.org/10.5006/c2013-02668.
Pełny tekst źródłaStreszczenie:
Abstract Corrosion of containment liners has been observed on the outside surface that is in contact with the concrete containment building. Corrosion initiated on the outer surface of the liner, or the surface that is in contact with the concrete containment building wall, has been associated with foreign material left embedded in the concrete. Macrocell-accelerated localized corrosion appears to be the corrosion mechanism for outer diameter corrosion (OD-corrosion) of steel containment liners. Once initiated, localized corrosion can continue to propagate over a period of many years because the thick sections of concrete have sufficient water content and the ionic conductivity necessary to support the electrochemical corrosion reactions. The model presented depicts the electrochemical current density (and therefore corrosion rate) estimated due to the steel liner and rebar interaction with the foreign material at the point the foreign material is in contact with the liner. The model can be used to determine the probability of containment liner failure due to corrosion for the possible situation of a foreign material at the liner/concrete interface creating the macrocell as discussed above.
6
Hoffman, E. N., P. E. Zapp, B. J. Wiersma, and K. H. Subramanian. "Inhibiting Localized Corrosion in Mild Carbon Steel." In CORROSION 2009. NACE International, 2009. https://doi.org/10.5006/c2009-09432.
Pełny tekst źródłaStreszczenie:
Abstract Controls on the solution chemistry are in place to prevent the initiation and propagation of pitting and stress corrosion cracking in high level waste (HLW) tanks. These controls are based upon a series of experiments performed using simulated solutions on materials used for construction of the tanks, namely ASTM A537 carbon steel. An experimental program was undertaken to investigate reducing the minimum molar nitrite concentration required to confidently inhibit pitting. The experimental results and conclusions provided herein will support a statistical basis to quantify the probability of pitting for the tank wall, when exposed to various solutions containing dilute concentrations of nitrate and nitrite. Coupon testing was performed within the framework of the statistical test matrix to determine the pitting propensity associated with inhibitor concentrations. The visual observation results indicate a potential for inhibitor reductions without consequence in the solution space. The majority of corrosion occurred at the interface of the solution and vapor space. Only one sample with the dilute concentration of both nitrate and nitrite exhibited visible pitting in the solution space.
7
Fuller, Ross K., and John W. McCarthy. "Recovery from Low pH Excursions in Cooling Water Systems Using All-Organic Treatment Programs." In CORROSION 1987. NACE International, 1987. https://doi.org/10.5006/c1987-87158.
Pełny tekst źródłaStreszczenie:
Abstract A low pH excursion can cause severe damage to an open recirculating cooling system which can cause a plant to shut down. With properplanning, the probability of having a pH excursion can be reduced but not eliminated entirely. Assuming that an accidental excursion has a finite probability of occurring, proper planning can minimize the effects of low pH. Once control of pH has been regained after a low pH excursion, a program of repassivation is necessary to minimize corrosion of active metal surfaces. Depending upon the severity of an excursion, repassivation using an all-organic corrosion inhibitor may be more difficult and time consuming than with other in- hibitors. This paper provides suggestions on how to reduce the probability of having a low pH excursion, details plans on how to regain control of the pH, and presents step-by-step instructions to reestablish the water treatment program when an all-organic corrosion inhibitor is being used.
8
Sato, Eiji, Hideo Abo, and Tomomi Murata. "Life Time Estimation and Accelerated Stress Corrosion Cracking Test of Stainless Steel in a Neutral Chloride Environment." In CORROSION 1989. NACE International, 1989. https://doi.org/10.5006/c1989-89097.
Pełny tekst źródłaStreszczenie:
Abstract This paper presents a new accelerated stress corrosion cracking (SCC) test method that simulates changes in actual environmental conditions to evaluate the service life of structural materials. The time to failure of AISI304 stainless steel, as tested by the new SCC test apparatus, is analyzed in terms of statistical probability and new indexes of SCC are described.
9
van Os, M. T., P. van Mastrigt, and G. G. J. Achterbosch. "The Utilization of a Pipeline Integrity Management System for ECDA Management within Gasunie." In CORROSION 2008. NACE International, 2008. https://doi.org/10.5006/c2008-08142.
Pełny tekst źródłaStreszczenie:
Abstract Gasunie has utilized External Corrosion Direct Assessment (ECDA) as proposed by the NACE as a valuable method to assess the corrosion threat to unpiggable pipelines. In addition, a new probabilistic methodology has been adopted to quantify the results of an ECDA and to account for any uncertainties experienced throughout the process. This approach, based on Structural Reliability Analysis (SRA) and Bayesian statistics, uses the data gathered in the pre-assessment to calculate a failure frequency for each ECDA region defined. In the indirect inspections step, the method allows automatic updating of the expected number of both coating and corrosion defects based on the results of two aboveground surveys (one for the detection of each). In the direct examinations step, the method uses the results from excavations to automatically update the performance characteristics of the survey techniques (e.g. probabililty of detection and probability of false indication), the time of initiation of corrosion defects, the defect depth, corrosion growth rate and several other relevant parameters. The failure frequency is updated accordingly. If desired, this updating can be performed after each excavation, until the failure frequency is sufficiently low. This allows the integrity manager to minimize the total number of excavations and thus reduce the overall cost of the ECDA process. Finally, in the post-assessment step a reassessment interval is calculated for the pipeline under investigation. In 2007 Gasunie has implemented the abovementioned methodology as part of its pipeline integrity management system, PiMSlider. The DA module has now become an integral part of the system, thereby enabling highly accurate, reproducible and time saving integrity analyses of the Gasunie grid. The DA module will be described in this paper by using an example of a part of a Gasunie pipeline that has recently been subjected to ECDA.
10
Zhang, Zhao-jiang. "Prediction of Subsidence in Steep Seam Mining Based on Probability Integral." In 2010 2nd International Conference on Intelligent Human-Machine Systems and Cybernetics (IHMSC). IEEE, 2010. http://dx.doi.org/10.1109/ihmsc.2010.45.
Pełny tekst źródłaRaporty organizacyjne na temat "STEEP PROBABILITY"
1
Mauney, Moghissi, and Sridhar. L51907 Internal Corrosion Risk Assessment and Management of Steel Pipelines. Pipeline Research Council International, Inc. (PRCI), 2001. http://dx.doi.org/10.55274/r0011241.
Pełny tekst źródłaStreszczenie:
The objective of this work is to provide a risk assessment and management software tool that will: (i) Provide probability of pipeline segment leak versus time for each pipeline segment of concern based on past laboratory research, (ii) Provide a means of conducting a formal interview for Probability of Leak where data is not available, and (iii) Provide an analysis tool for timing inspection/repair/replacement of each pipeline segment with a maximized Net Present Value (NPV) for the group.
2
Campbell, Leslie E., Luke R. Snyder, Julie M. Whitehead, Robert J. Connor, and Jason B. Lloyd. Probability of Detection Study for Visual Inspection of Steel Bridges: Volume 1—Executive Summary. Purdue University, 2019. http://dx.doi.org/10.5703/1288284317103.
Pełny tekst źródła
3
Campbell, Leslie E., Luke R. Snyder, Julie M. Whitehead, and Robert J. Connor. Probability of Detection Study for Visual Inspection of Steel Bridges: Volume 2—Full Project Report. Purdue University, 2019. http://dx.doi.org/10.5703/1288284317104.
Pełny tekst źródła
4
de Luis, Mercedes, Emilio Rodríguez, and Diego Torres. Machine learning applied to active fixed-income portfolio management: a Lasso logit approach. Banco de España, 2023. http://dx.doi.org/10.53479/33560.
Pełny tekst źródłaStreszczenie:
The use of quantitative methods constitutes a standard component of the institutional investors’ portfolio management toolkit. In the last decade, several empirical studies have employed probabilistic or classification models to predict stock market excess returns, model bond ratings and default probabilities, as well as to forecast yield curves. To the authors’ knowledge, little research exists into their application to active fixed-income management. This paper contributes to filling this gap by comparing a machine learning algorithm, the Lasso logit regression, with a passive (buy-and-hold) investment strategy in the construction of a duration management model for high-grade bond portfolios, specifically focusing on US treasury bonds. Additionally, a two-step procedure is proposed, together with a simple ensemble averaging aimed at minimising the potential overfitting of traditional machine learning algorithms. A method to select thresholds that translate probabilities into signals based on conditional probability distributions is also introduced.
5
Schultz, Martin, Leslie Campbell, Ramsay Bell, and Phillip Sauser. A study of phased-array ultrasonic testing (PAUT) for detecting, sizing, and characterizing flaws in the welds of existing hydraulic steel structures (HSS). Engineer Research and Development Center (U.S.), 2024. http://dx.doi.org/10.21079/11681/48750.
Pełny tekst źródłaStreszczenie:
Hydraulic steel structures (HSS) are components of navigation, flood control, and hydropower projects that control or regulate the flow of water. Damage accumulates in HSS as they are operated over time, and they must be inspected periodically. This is often accomplished using nondestructive testing (NDT) techniques. If damage is detected, the structure’s fitness for continued service must be evaluated, which requires information on the location and size of discontinuities. This information can be obtained using ultrasonic testing (UT) techniques. However, there is limited information on the reliability of UT techniques with respect to detecting, sizing, and characterizing flaws in HSS. This study addresses this gap. Round-robin experiments were carried out using phased-array ultrasonic testing (PAUT) to scan weld specimens representing a variety of HSS geometries. The results of the round-robin experiments were analyzed to estimate the probability of detection (POD) and to assess the influence of factors potentially affecting POD. Uncertainty in estimates of flaw length and height were described, and partial safety factors were derived for use in fitness-for-service analyses. These results demonstrate the importance of the technician as a factor influencing the reliability of NDT techniques applied to HSS.
6
Schultz, Martin, Leslie Campbell, Ramsay Bell, and Phillip Sauser. A study of phased-array ultrasonic testing (PAUT) for detecting, sizing, and characterizing flaws in the welds of existing hydraulic steel structures (HSS). Engineer Research and Development Center (U.S.), 2024. http://dx.doi.org/10.21079/11681/48735.
Pełny tekst źródłaStreszczenie:
Hydraulic steel structures (HSS) are components of navigation, flood control, and hydropower projects that control or regulate the flow of water. Damage accumulates in HSS as they are operated over time, and they must be inspected periodically. This is often accomplished using nondestructive testing (NDT) techniques. If damage is detected, the structure’s fitness for continued service must be evaluated, which requires information on the location and size of discontinuities. This information can be obtained using ultrasonic testing (UT) techniques. However, there is limited information on the reliability of UT techniques with respect to detecting, sizing, and characterizing flaws in HSS. This study addresses this gap. Round-robin experiments were carried out using phased-array ultrasonic testing (PAUT) to scan weld specimens representing a variety of HSS geometries. The results of the round-robin experiments were analyzed to estimate the probability of detection (POD) and to assess the influence of factors potentially affecting POD. Uncertainty in estimates of flaw length and height were described, and partial safety factors were derived for use in fitness-for-service analyses. These results demonstrate the importance of the technician as a factor influencing the reliability of NDT techniques applied to HSS.
7
Clausen, Jay, Michael Musty, Anna Wagner, Susan Frankenstein, and Jason Dorvee. Modeling of a multi-month thermal IR study. Engineer Research and Development Center (U.S.), 2021. http://dx.doi.org/10.21079/11681/41060.
Pełny tekst źródłaStreszczenie:
Inconsistent and unacceptable probability of detection (PD) and false alarm rates (FAR) due to varying environmental conditions hamper buried object detection. A 4-month study evaluated the environmental parameters impacting standoff thermal infra-red(IR) detection of buried objects. Field observations were integrated into a model depicting the temporal and spatial thermal changes through a 1-week period utilizing a 15-minute time-step interval. The model illustrates the surface thermal observations obtained with a thermal IR camera contemporaneously with a 3-d presentation of subsurface soil temperatures obtained with 156 buried thermocouples. Precipitation events and subsequent soil moisture responses synchronized to the temperature data are also included in the model simulation. The simulation shows the temperature response of buried objects due to changes in incoming solar radiation, air/surface soil temperature changes, latent heat exchange between the objects and surrounding soil, and impacts due to precipitation/changes in soil moisture. Differences are noted between the thermal response of plastic and metal objects as well as depth of burial below the ground surface. Nearly identical environmental conditions on different days did not always elicit the same spatial thermal response.
8
Bedoya-Maya, Felipe, Lynn Scholl, Orlando Sabogal-Cardona, and Daniel Oviedo. Who uses Transport Network Companies?: Characterization of Demand and its Relationship with Public Transit in Medellín. Inter-American Development Bank, 2021. http://dx.doi.org/10.18235/0003621.
Pełny tekst źródłaStreszczenie:
Transport Network Companies (TNCs) have become a popular alternative for mobility due to their ability to provide on-demand flexible mobility services. By offering smartphone-based, ride-hailing services capable of satisfying specific travel needs, these modes have transformed urban mobility worldwide. However, to-date, few studies have examined the impacts in the Latin American context. This analysis is a critical first step in developing policies to promote efficient and sustainable transport systems in the Latin-American region. This research examines the factors affecting the adoption of on-demand ride services in Medellín, Colombia. It also explores whether these are substituting or competing with public transit. First, it provides a descriptive analysis in which we relate the usage of platform-based services with neighborhood characteristics, socioeconomic information of individuals and families, and trip-level details. Next, factors contributing to the election of platform-based services modeled using discrete choice models. The results show that wealthy and highly educated families with low vehicle availability are more likely to use TNCs compared to other groups in Medellín. Evidence also points at gender effects, with being female significantly increasing the probability of using a TNC service. Finally, we observe both transit complementary and substitution patterns of use, depending on the context and by whom the service is requested.
9
Weller, Joel I., Ignacy Misztal, and Micha Ron. Optimization of methodology for genomic selection of moderate and large dairy cattle populations. United States Department of Agriculture, 2015. http://dx.doi.org/10.32747/2015.7594404.bard.
Pełny tekst źródłaStreszczenie:
The main objectives of this research was to detect the specific polymorphisms responsible for observed quantitative trait loci and develop optimal strategies for genomic evaluations and selection for moderate (Israel) and large (US) dairy cattle populations. A joint evaluation using all phenotypic, pedigree, and genomic data is the optimal strategy. The specific objectives were: 1) to apply strategies for determination of the causative polymorphisms based on the “a posteriori granddaughter design” (APGD), 2) to develop methods to derive unbiased estimates of gene effects derived from SNP chips analyses, 3) to derive optimal single-stage methods to estimate breeding values of animals based on marker, phenotypic and pedigree data, 4) to extend these methods to multi-trait genetic evaluations and 5) to evaluate the results of long-term genomic selection, as compared to traditional selection. Nearly all of these objectives were met. The major achievements were: The APGD and the modified granddaughter designs were applied to the US Holstein population, and regions harboring segregating quantitative trait loci (QTL) were identified for all economic traits of interest. The APGD was able to find segregating QTL for all the economic traits analyzed, and confidence intervals for QTL location ranged from ~5 to 35 million base pairs. Genomic estimated breeding values (GEBV) for milk production traits in the Israeli Holstein population were computed by the single-step method and compared to results for the two-step method. The single-step method was extended to derive GEBV for multi-parity evaluation. Long-term analysis of genomic selection demonstrated that inclusion of pedigree data from previous generations may result in less accurate GEBV. Major conclusions are: Predictions using single-step genomic best linear unbiased prediction (GBLUP) were the least biased, and that method appears to be the best tool for genomic evaluation of a small population, as it automatically accounts for parental index and allows for inclusion of female genomic information without additional steps. None of the methods applied to the Israeli Holstein population were able to derive GEBV for young bulls that were significantly better than parent averages. Thus we confirm previous studies that the main limiting factor for the accuracy of GEBV is the number of bulls with genotypes and progeny tests. Although 36 of the grandsires included in the APGD were genotyped for the BovineHDBeadChip, which includes 777,000 SNPs, we were not able to determine the causative polymorphism for any of the detected QTL. The number of valid unique markers on the BovineHDBeadChip is not sufficient for a reasonable probability to find the causative polymorphisms. Complete resequencing of the genome of approximately 50 bulls will be required, but this could not be accomplished within the framework of the current project due to funding constraints. Inclusion of pedigree data from older generations in the derivation of GEBV may result is less accurate evaluations.
10
Fu, Gongkang, and Gabriel Bryk. BrM Quantity-Based Bridge Element Deterioration/Improvement Modeling and Software Tools. Illinois Center for Transportation, 2024. http://dx.doi.org/10.36501/0197-9191/24-005.
Pełny tekst źródłaStreszczenie:
This study reviewed the state of the art and practice in bridge element deterioration / improvement modeling. It also developed a new and practical method for such modeling using element quantities in BrM inspection records along with bridge age. For reliable forecasting, this method uses these quantities directly to determine transition probability matrices (TPMs). The example TPMs were found age-dependent for the do-nothing case. Results show that this approach is effective in forecasting the bridge element life. Condition improvement TPMs were also similarly derived from the quantity evolution for consistency. Examples of renewal construction work are deck overlay of micro-silica concrete, steel beam repainting, bridge cleaning, etc. Two computer software programs in Microsoft Excel were developed to obtain TPMs for do-nothing deterioration and condition improvement. Bridge owners may use the tools to generate TPMs for any element whose inspection records are provided. As a result, TPMs can be continuously updated whenever more inspections are performed and their records are included as input to the software programs. In addition, the software tools are transparent for the user to perform expert elicitation, especially when the inspection records are questionable or unavailable. Such activity can be informatively guided by the results from the software, as illustrated by two application examples in the delivered programs. This new concept and associated tools may be applied by other bridge owners using the BrM system. Two application examples for elements 12 and 107 in the programs can be readily transplanted to other states as a starting point for application of the research products herein. They show that the age-dependent TPM is able to realistically replicate deterioration for the do-nothing case, particularly the behavior of faster deterioration while aging. They also demonstrate that TPMs for different renewal construction work are able to contrast their effectiveness, such as micro-silica overlays vs. sealing for a concrete deck.