Probability Of Breaking Research Articles

A comparative study of statistical and machine learning methods to infer causes of pipe breaks in water supply networks

ABSTRACT Water supply pipes age, deteriorate and break, which puts at risk the continuous provision of safe potable water endangering the public health in cities. Risk management methods are increasingly applied to optimise the capital investment for pipe replacement and rehabilitation, taking into account the probability and hydraulic impact of pipe breaks. As part of this process, however, historic pipe break data and statistical methods should be utilised to gather causal insights for past breaks to inform operational changes and/or capital investment decisions in order to reduce future breaks. This paper presents a comparative study of statistical and machine learning methods to carry out an exploratory causal analysis for historic pipe breaks in an operational water supply network. Regression models for count data and probabilistic models have been developed. The performance of these models was assessed and enhanced with the introduction of interactions and the inclusion of different network representations.

The discontinuation of the EUR/CHF minimum exchange rate: information from option-implied break probabilities

Abstract We derive risk-neutral probability densities for future euro/Swiss franc exchange rates as implied by option prices. We find that the credibility of the Swiss franc floor decreased somewhat as the spot exchange rate approached the lower bound of 1.20 CHF per euro. We also compare the forecasting performance of a random walk benchmark model with an error-correction model (ECM) augmented with option-implied break probabilities of breaching the currency floor. We find some evidence that the augmented ECM has an informational advantage over the random walk when using one-month break probabilities. But we find that one-month option-implied densities cannot predict the entire range of exchange rate realizations.

Modeling SAOS Yield Stress of Cement Suspensions: Microstructure-Based Computational Approach.

Two static yield stress models, one known as YODEL and the newly proposed BreakPro, based on inter-particle bond breaking probability, were employed to comparatively simulate the yield stress of cement suspensions, induced by oscillatory rheological tests with small amplitude oscillatory shear (SAOS). This yield stress occurs at a critical strain in the order of 0.01%, and is commonly attributed to the limit of the linear viscoelastic domain, where attractive forces bridge the cement particles and form a flocculated particle network. YODEL is based on van der Waals (vdW) interaction forces to describe the yield stress for flow onset at a critical strain of a few percent, developed for simple non-reactive particulate suspensions. However, due to the high pH and reactivity of cementitious suspensions, their particle interaction forces are much higher than vdW. Therefore, until now, the YODEL adaptations to cementitious suspensions did not explicitly consider the microstructural-based salient feature of the original model, but used it as an implicit fitting parameter to scale the average attractive force. In this paper, the force is inversely estimated using the full power of the two microstructural-based models, presenting a new mathematical tool for investigating the fragility of the rigid percolated structure of cement suspensions. The model parameters were calibrated on measured yield stresses obtained by SAOS measurements in a high-sensitivity rheometer. The estimated forces were found to be 5.57 (BreakPro) and 1.43 (YODEL) times higher than typical van der Waals forces. The YODEL percolation threshold of 21% turned out to be significantly lower than the one found by the BreakPro model (37%). This indicated that BreakPro modeling assumptions are better suited for the description of yield stress at SAOS critical strain than the YODEL model.

Послідовний дворівневий захист інформації з імовірнісний надійністю

У даній роботі проведено теоретичні дослідження фізичного процесу злому для послідовного дворівневого технічного захисту інформації з ймовірною надійністю. У дослідженнях використовується підхід, пов'язаний з надійністю різної апаратури, технічних пристроїв і систем, які досить ретельно вивчені та забезпечили гарний практичний результат з кількісною ймовірною оцінкою. Для розрахунків і оцінки можливостей послідовного дворівневого технічного захисту інформації використовувалися однорівневі ТЗІ з ймовірною надійністю, які запропоновані і розглянуті в роботах Б. Журиленка. У даній роботі використовувався метод побудови послідовного дворівневого технічного захисту інформації з ймовірною надійністю і можливість порівняння її з еквівалентним однорівневим захистом. Таке порівняння може виявитися корисним при оцінці і порівнянні багаторівневих ТЗІ, оскільки такий підхід дозволить оцінювати різні структури багаторівневих захистів і досить просто порівнювати проектовані й існуючі ТЗІ з єдиної точки зору. Проведені дослідження показали, що поверхня розподілу максимумів ймовірностей злому еквівалентного однорівневого ТЗІ в повному обсязі збігається з розподілом максимумів ймовірності злому дворівневого ТЗІ. Тому порівняння захистів можливо тільки в обраному для аналізу напрямку злому. Для аналізу і порівняння захищеності інформації в інших напрямках необхідно за запропонованою методикою розрахувати і побудувати розподіл максимумів ймовірності злому для цих напрямків. В роботі запропоновано спосіб визначення реальної ймовірності злому дворівневого захисту не за максимальним значенням ймовірності злому, а з розподілу ймовірності злому послідовної дворівневої ТЗІ, так як злом ТЗІ не обов'язково може відбуватися при максимальних значеннях ймовірності злому. У цьому випадку за побудованими поверхнями ймовірностей злому реальну надійність ТЗІ можна визначати для будь-якого напрямку злому.

Monte Carlo simulation for uncertainty quantification in reservoir simulation: A convergence study

The current work illustrates the convergence properties of a Monte Carlo Simulation (MCS) used to quantify the geological uncertainty in reservoir simulation. We investigate the convergence behavior of MCS on 3D, 3-phase, highly heterogeneous reservoirs through real field data from a major oil and gas company. We generate 10,000 realizations of a geological model and run a Black-Oil flow simulation using a commercial reservoir simulator and a synchronous parallel implementation. The distributions of the moments and quantiles of the Net Present Value (NPV) are presented in the form of their Cumulative Density Functions (CDF). We also show the distributions of the break even time (BET) and the probability of breaking even in order to see the effect of considering quantities that are different in nature. We use log-plots to assess the convergence of the results, and verify that the convergence of the quantities of interest follows a squared-root law in the number of realizations used. We quantify the relative error made on various quantities and illustrate that the use of a small ensemble can yield errors of hundreds of percents, and that lowering the error to a given precision (e.g. below ten percent) can require thousands of realizations. For decision making and profitability assessments, using large sets of realizations is now feasible due to the availability of fast, distributed architectures and the parallel nature of MCS. Our results suggest that the improvement in the quality of the results is significant and well worth the extra effort. For optimization and sensitivity studies, running large ensembles is still intractable but yields sets of quantiles that can be used as a Reduced Order Model (ROM). Setting up a test case using this dataset is under consideration, and could provide an interesting integrated setup for comparisons of uncertainty quantification (UQ) methods.

Records for the moving average of a time series

We investigate how the statistics of extremes and records is affected when taking the moving average over a window of width p of a sequence of independent, identically distributed random variables. An asymptotic analysis of the general case, corroborated by exact results for three distributions (exponential, uniform, power-law with unit exponent), evidences a very robust dichotomy, irrespective of the window width, between superexponential and subexponential distributions. For superexponential distributions the statistics of records is asymptotically unchanged by taking the moving average, up to interesting distribution-dependent corrections to scaling. For subexponential distributions the probability of record breaking at late times is increased by a universal factor Rp , depending only on the window width.

Improving the energy efficiency of wide crossings of overhead power lines

The use of new generation wires in the design of wide spans of overhead power lines over water barriers and large gorges can increase their transmission capacity and increase reliability. However, when large currents flow, load losses in line also increase. Thus, it is necessary to obtain a methodology for technical and economic comparison of design options for overhead power lines over large crossings, which enables to determine the most cost-effective version of the project with high mechanical reliability. For comparative analysis, five options for wide spans of overhead power lines over the river with new-generation wires of Russian production were compiled: Aluminium Alloy Conductor Steel Reinforced, Z-type (high conductivity), Thermal-Resistant Conductor, Aluminium Compozite Core Conductor, ASk2y. Option with Aluminium Conductor Steel Reinforced wire was taken as the source. For the first option, the crossing scheme E-A-A-E was selected, for the remaining options E-I-I-E scheme was considered. For the modes of maximum loads, minimum temperature and average annual conditions, the mechanical calculation of wires was carried out using the method of permissible stresses. The wire bending deflections were determined in accordance with the theory of the catenary curve. The method of integrated indicators was used to perform a technical and economic comparison of these options. The calculation results showed that among the proposed options, the most optimal is a crossing with the ACCC wire having minimum relative investment per 1 MW of transmitted electricity and minimal power loss. The transmission capacity of the line with this wire is increased by 1.8 times, and the cost of crossing is reduced by 16%. Due to the compact design of wire, the probability of ice formation on wire is reduced, and the reduced bending deflection reduces the probability of wire break due to natural environmental influences.

Bandwidth and Mobility Based Stable Route Formation in Mobile AD HOC Networks

Paper Usually, Mobile Ad hoc Networks (MANET) is a dynamic background thus complicated to supply a perfect resolution to convince the Quality of Service (QoS) needs for many applications. In this paper, we introduce a mechanism, namely Bandwidth and Mobility based Stable Route (BMSR) Formation for increasing network efficiency in MANET. In this mechanism, we choose the relay node by the node mobility, bandwidth and quality of link. This mechanism considerably increases the node reliability and stability in the network. Thus it diminishes the probability of link breaks and the overhead. The simulation analysis indicates that the proposed method provides guarantee QoS and network efficiency.

Computational analysis of adhesion between a cancer cell and a white blood cell in a bifurcated microvessel

Background and ObjectiveCancer is one of the diseases caused by irregular and uncontrolled growth of cells and their propagation into various parts of the body. The motion and adhesion of cancer cells in a blood vessel is a critical step in tumor progression that depends on some vascular parameters such as vessel branching. In this study, effect of microvessel branching on the bonds between a cancer cell and a white blood has been investigated as compared to an analogous problem in a straight vessel. MethodsThe analysis is performed using finite elements and fluid-structure interaction methods. Moreover, the equations for adhesion of the cancer cell to white blood cell are coded in MATLAB for calculating forces between them and the code is coupled directly and simultaneously with the COMSOL software. For fluid-structure interaction analysis, it is assumed that the properties of the blood and the cells are homogeneous and the fluid is incompressible and Newtonian. Cancer cell is modeled as a rigid body and white blood cell is assumed as linear elastic. ResultsThe results show that although the geometry of the vessel does not affect on the separation distance of cancer cell considerably, but at the area near a bifurcation, high fluctuations in cancer cell velocity is occurred due to increasing in number of bond formation between the cancer cell and the white blood cell. Accordingly, it can be predicted that higher concentration of adhered particles occurs near the bifurcations. Moreover, shear stress at the point of contact of the cancer cell and the white blood cell in the branched vessel is greater than that in the straight path. In addition to, the probability of breaking of the bond between the cancer cell and the white blood cell increases in the branched vessel. ConclusionsThrough consideration in the adhesion charts of this study along with observations from medical interventions such as drug delivery to cancer patients, considerable developments on the treatment or prevention of cancer metastasis may be achieved.

Improving the cost-performance ratio of well construction using a multi-stage hydrostatic pressure tester

The article considers the issue of improving the cost-performance ratio of well drilling through the use of a device for drill and production pipes, which allows for multi-stage hydrostatic pressure testing during preparatory work in the well before liner completion, well lining and other technological operations. The authors present the results of a patent analysis on the problem under study and prove the need to create a device with a simpler design with a reduced probability of breaking and allowing multiple pressure testing of pipes in the well without lifting them to the surface. The article presents a scheme of the device and the technology of its operation in the well. The results of factory tests of a prototype device with a diameter of 105 mm showed its efficiency and practicality for technological processes during the drilling and exploitation of deep oil and gas wells.

Design method and evaluation of the working single technical protection information on the selected direction of hacking

This paper shows an alternative to the known methods, the ability to design and evaluate a single technical information protection (TZI) in the chosen direction of hacking. Namely, the possibility of constructing a TZI according to the selected parameters: the direction and the necessary attempt to hack or the necessary selected attempt and its time to hack is shown. Using the proposed method for designing and evaluating a single TZI according to the selected parameters of hacking, one can obtain the distribution surface of the probability of breaking into the protection and the distribution surface of the maximums of the probability of breaking, the effectiveness of the chosen protection, the necessary financing for this type of protection, the risks of investment losses and risks of general financial losses. The obtained parameters of information protection can be compared with the required design parameters and determine their compliance with the specified TZI. In case of non-compliance with the requirements of the technical specifications, it is necessary to choose a different type of protection and use this method to calculate new protection parameters. When assessing a working TZI, according to the real, experimentally recorded, direction of hacking and the designed TZI, it is possible to determine the probabilistic reliability of a single working defense, as well as at what attempt and time its real physical hacking is possible. Based on the results of the analysis of the state of the working TZI, a decision is made to extend the work, replace or modernize the existing information protection. The paper presents a calculation method with specific selected parameters for designing and evaluating a single TZI in the chosen direction of hacking. Charts have been built for specific protection and hacking parameters, with the help of which the possible attempt and time of this attempt to break the TZI have been determined. Using a graphic illustration shows the physical process of hacking information protection.

Reliability Analysis of a Pre-Cracked Structure in Accidental Operation Conditions

Evaluating the integrity of a structure consists in proving its ability to realize its mechanical functions for all modes of loading, normal or accidental, and throughout its lifetime. In the context of nuclear safety, the most important structures consider the presence of a degradation grouping several aspects, such as cracks. In this context, the fracture mechanics provide the tools needed to analyze cracked components. Its purpose is to establish break criteria for judging loading margins in normal or accidental operating conditions. The seismic load is one of the dominant loads for the failure assessment of the pipes. Its probabilistic dispersion, however, was not taken into account in the past probabilistic fracture mechanics analysis. The objective of this paper is to simulate and analyze the effect of abnormal stress on the reliability of tow pipe sizes. As result the seismic stress has more effect on the break probability, but not for the leak probability. In the case without a seismic load, the break probability is mainly dominated by an initial crack size. The earthquake has much effect on the break probability for the large diameter pipe, not for the small diameter pipe. In the large diameter pipe, the break probability increases gradually with the time. The leak probability of both pipe sizes is not affected by the seismic curve.

Performance and Profitability of Fungicides for Managing Soybean White Mold: A 10-Year Summary of Cooperative Trials.

White mold, caused by Sclerotinia sclerotiorum, is a yield-limiting disease of soybean in Brazil. Uniform fungicide trials have been conducted annually since 2009. Data from 74 cooperative field trials conducted over a 10-year period were assembled. We selected five fungicides applied two times around flowering: dimoxystrobin plus boscalid (DIMO+BOSC), carbendazim plus procymidone (CARB+PROC), fluazinam (FLUZ), fluopyram (FLUO), and procymidone (PROC). For comparison, thiophanate-methyl (TMET) applied four times was also included as a low-cost treatment. Network models were fitted to the log of white mold incidence (percentages) and log of sclerotia mass data (grams/hectare) and to the nontransformed yield data (kilograms/hectare) for each treatment, including the untreated check. Back-transformation of the meta-analytic estimates indicated that the lowest and highest mean (95% confidence interval [CI]) percent reductions in incidence and sclerotia mass were 54.2 (49.3 to 58.7) and 51.6% (43.7 to 58.3) for TMET and 83.8 (79.1 to 87.5) and 87% (81.9 to 91.6) for CARB+PROC, respectively. The overall mean (95% CI) yield responses ranged from 323 kg/ha (247.4 to 400.3) for TMET to 626 kg/ha (521.7 to 731.7) for DIMO+BOSC, but the variance was significantly reduced by a binary variable (30% threshold) describing disease incidence in the untreated check. On average, an increment of 352 kg/ha was estimated for trials where the incidence was >30% compared with the low-disease scenario. Hence, the probability of breaking even on fungicide costs for the high-disease scenario was >65% for the more effective, but more expensive fungicide (FLUZ) than TMET. For the low-disease scenario, profitability was less likely and depended more on variations in fungicide cost and soybean price.

Rapid microwave-assisted biomass delignification and lignin depolymerization in deep eutectic solvents

Biomass deconstruction and lignin depolymerization was performed using three different deep eutectic solvents. Various temperature (110°, 130°, and 150 °C) and time (1, 5, 10, 15 min) conditions were tested in a 2450 MHz microwave reactor. Oxalic acid (130 °C, 15 min) and formic acid DES (150 °C, 15 min) gave the highest lignin yield. Microwave heating reduced the processing time significantly. NMR characterization shows that microwave heating promotes selective bond cleavage during lignin depolymerization and has a narrow molecular weight distribution compared to conventional heating techniques. Molecular dynamic simulations showed that certain lignin bonds are stretched under the electric field imparted during microwave irradiation, increasing its probability of breaking.

Break probability evaluation for a weld in piping of the water-cooled ceramic breeder blanket for CFETR

The Water-cooled ceramic breeder (WCCB) blanket is one of the three major blanket design concepts for CFETR. Weld failures will result in the blanket failure and reduce blanket reliability. Especially, weld failures in piping of the blanket may cause loss of coolant accidents (LOCAs) which are typical initiating events in the probabilistic safety analysis (PSA) for CFETR. Determining the failure probabilities of welds at coolant piping in the blanket is necessary and helpful to evaluate the occurrence frequencies of the LOCAs, accelerating the construction of PSA reliability database for CFETR. The present paper provides a probabilistic model to estimate the probability of failure at a weld in coolant piping of WCCB blanket. A girth butt weld in piping of the first wall (FW) was chosen as the numerical example to demonstrate the model. The probabilities of the weld breakage over the design lifetime of CFETR were estimated. Sensitivity analyses for input parameters of the probabilistic model, such as operational temperature and pressure, were carried out as well, with results indicating that the effects of uncertainties associated with initial crack size and crack growth factor on break probabilities estimated are significant.

PROBABILISTIC MODELING AND ANALYSIS OF DNA FRAGMENTATION

Deoxyribonucleic Acid (DNA) sequencing has become indispensable to the modern biological and medicine sciences. DNA fragmentation is a preliminary step in a dominant technique called shotgun sequencing that provides a time and cost effective strategy for the DNA sequencing. In this paper, we propose a probabilistic model for the random DNA fragmentation and derive an average number of fragments with the suitable length along with the probability of covering the entire DNA strand through the de novo assembly or the referenced-based mapping assembly. We formulate the coverage problem in terms of the probability of bond breaking between nucleotides and the number of DNA molecules participating in the fragmentation process, and provide insights into the optimal DNA fragmentation. We obtain the lower bound for the minimum number of suitable fragments required to reconstruct the DNA strand with the specified reliability. We evaluate the derived results with our DNA Fragmentation Tool which demonstrate, the validity of these results based on our model. Finally, we update our model with respect to the fragments’ size distribution of real data.

Determinants of mortality in Pinus banksiana (Pinaceae) stands during an ice storm and its effect on stand spatial structure1

Ice storms are a major source of tree mortality in some regions of the eastern North American deciduous forest, but are rare in the boreal forest. As climate changes, ice storms are predicted to be more common in the boreal forest, creating new challenges for forest management. In 2012, an ice storm damaged Pinus banksiana (Lamb.) stands throughout southeast Manitoba, Canada. We assessed damage in a 98- and a 32-yr-old stand. In both stands, half the trees broke near the base of the crown. Trees with a deeper crown were more likely to break in the young stand and less likely to break in the old stand. In the young stand taller trees were also more likely to break. There was no relationship between tree diameter and the probability of a tree breaking in either stand. Tree mortality increased the bare area around surviving trees by 52% and 119% in the young and old stands, respectively. This resulted in a 42% increase in canopy openness in the old stand but did not alter the pattern of spatial distribution of trees. Before the storm, trees in the young stand showed a dispersed distribution, indicative of density-dependent mortality. This dispersion was lost after the storm and suggests that, along with selection of shorter trees, ice storms reorganize the structure of forests undergoing self-thinning.

Starch and hexoses concentrations as physiological markers in dormancy progression of sweet cherry twigs

KEY MESSAGE: High starch concentrations in woody tissue of sweet cherry trees were associated with deep stages of dormancy, while increasing concentrations of hexoses were related to the dormancy release process. Dormancy is an intrinsic characteristic of deciduous forest and fruit trees. Release from dormancy and subsequent bud burst occur after chill requirements (CR) have been met. Currently, chilling metrics are poorly interchangeable among climates, probably due to a lack of physiological parameters involved in earlier model development, and, therefore, the reported CR values differ across locations. Here, we propose a way to improve our understanding on physiological markers involved in dormancy of deciduous fruit trees studying the dynamics of starch and hexoses (glucose + fructose) in sweet cherry twigs. Probabilities of bud break were estimated through logistic regression analysis using as independent variable the concentration of carbohydrates. In this experiment, we used 960 twigs and 160 sub-samples of twig portions (~ 2 cm of stem) from 8 sweet cherry cultivars exposed to different amounts of chill in the field. The timing of bud burst in forcing conditions and the concentration of starch and hexoses in the sub-samples were recorded. We found that concentrations of starch and hexoses are closely related to dormancy progression. Specifically, starch concentrations decreased by 43%, while concentrations of hexoses increased by 58% during the transition from 16 to 70 Chill Portions. Responses differed among varieties at the same chill received in the orchard. The logistic regression analysis revealed that the predicted probability of bud break at the moment of recorded bud burst was highest (i.e., up to 0.5) in the varieties Santina, Skeena, Rainier, Lapins, Regina, Kordia and Bing. In contrast, the variety Sweetheart showed the lowest probability (i.e., 0.49) of having met its CR when bud burst was recorded. This may suggest that in this variety, carbohydrate metabolism is not the most important predictor involved in dormancy release. The method presented here improves our understanding on dormancy and might serve to focus further research on dormancy modeling. This is especially important in warm winter regions where the classical way of determining CRs and quantifying chill accumulation is consistently failing.

Cool skin signals observed from Advanced Along-Track Scanning Radiometer (AATSR) and in situ SST measurements

Nighttime cool skin sea surface temperature (SST) signals, defined in this study as the differences between the SSTskin from the Advanced Along-Track Scanning Radiometer (AATSR) onboard Envisat satellite and in situ SSTs from drifting buoys and moorings, ΔT = SSTskin − SSTinsitu, are investigated on a global scale from July 2002 to April 2012. Global mean ΔT, averaged over the full study period, is −0.13 K, with most values falling between −0.1 and −0.2 K. The dominant role of wind speed on the ΔT is shown, with weaker winds usually corresponding to a cooler skin. The effect of air-sea temperature difference is also significant: warm skin (ΔT > 0 K) can be observed under large positive air-sea temperature differences. Other geophysical variables, such as the total column water vapor, in situ SST, and net heat flux, also affect ΔT, but to a lesser degree. Significant increase of ΔT size with SSTinsitu is observed when SSTinsitu is >28 °C. Tropical waters, such as the tropical Indian Ocean and the tropical warm pool (western Pacific and eastern Indian Ocean), are more frequently covered with a cool skin, largely due to the calm winds, very warm waters (especially for SSTinsitu >28 °C), and other environmental conditions supporting the development of large cool skin events. The ΔT seasonal pattern in the southern hemisphere is more regular, compared to the northern hemisphere. In both hemispheres, larger cool skin signals are seen during the local summer, mainly due to weaker winds. According to several previous cool skin models, higher winds tend to result in thinner cool skin layer depths, and hence in smaller ΔT amplitudes, regardless of stronger evaporation and heat loss. Given that wind is closely coupled with waves and turbulent mixing with wave breaking, the dependencies of ΔT on a few wave parameters are also investigated. A strong (moderate) dependency of ΔT on wave height (wave steepness) is identified, while the dependency of ΔT on wave breaking probability is less discernible.

Impact of Climate Change on Flood Inundation Levels in Chereh Dam Failure Scenarios

This study evaluates the climate change impact to the depth of inundation due to dam breaks during a heavy rainfall through Hydrological Engineering Centre–River Analysis System (HEC-RAS). Increasing of intensity rainfall is an evidence of climate change exists and it explicitly informs that possibility of higher inflow rates will be also getting bigger. This fact become main concern in connection with raising probability of dam breaks with higher magnitude of flooding. This current study determines the flood inundation depth due to Chereh Dam failure by including the Climate Change Factor (CCF). The result of analysis point out that the depth and level of flood due dam break creates a significant impact and risk to the Kuantan City such as inundated of transportation networks and also various public facilities.