Academic literature on the topic 'Hazard vector'
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Journal articles on the topic "Hazard vector"
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Ni, Shun-Hao, De-Yi Zhang, Wei-Chau Xie, and Mahesh D. Pandey. "Vector-Valued Uniform Hazard Spectra." Earthquake Spectra 28, no. 4 (November 2012): 1549–68. http://dx.doi.org/10.1193/1.4000081.
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Uniform hazard spectra (UHS) have been used as design earthquakes in several design codes. However, as the results from scalar probabilistic seismic hazard analysis (PSHA), UHS do not provide knowledge about the simultaneous occurrence of spectral accelerations at multiple vibration periods. The concept of a single “design earthquake” is then lost on a UHS. In this study, a vector-valued PSHA combined with scalar PSHA is applied to establish an alternative design spectrum, named vector-valued UHS (VUHS). Vector-valued seismic hazard deaggregation (SHD) is also performed to determine the design earthquake in terms of magnitude, distance, and occurrence rate for the VUHS. The proposed VUHS preserves the essence of the UHS and can also be interpreted as a single design earthquake. To simplify the procedure for generating the VUHS, so that they can be easily incorporated into performance-based seismic design, an approximate method is also developed.
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Zhou, Di, Xiao Zhuang, Hongfu Zuo, Jing Cai, and Han Bao. "Hazard identification and prediction system for aircraft electrical system based on SRA and SVM." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 4 (January 29, 2020): 1014–26. http://dx.doi.org/10.1177/0954410019894121.
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The aircraft electrical system provides power for the normal operation of the aircraft. Its normal operation is critical to ensure the safe flight of the aircraft. Therefore, it is very important to identify the hazards in the aircraft electrical system. In this paper, a hazard identification and prediction system which can intelligently identify potential hazards in aircraft electrical system is proposed. The proposed hazard identification and prediction system mainly includes three processes: variable selection, hazard identification, and hazard prediction. In the process of variable selection, the stepwise regression analysis is used to select 8 main parameters that have the major influence on the DC bus voltage value from 18 parameters. In the process of hazard identification, support vector machine is used to identify pre-existing hazards in electrical system based on the status of all components. The identification accuracy of the support vector machine is 92.3%. When the electrical system does not have unacceptable hazards, a prediction of the variation range of the DC bus voltage value in the aircraft electrical system is performed. The average prediction relative error of support vector machine is only 0.86%. Overall, the identification accuracy and average prediction relative error show that the proposed hazard identification and prediction system can accurately and effectively identify and predict the hazards in the aircraft electrical system.
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Dhulipala, Somayajulu L. N., Adrian Rodriguez-Marek, and Madeleine M. Flint. "Computation of Vector Hazard Using Salient Features of Seismic Hazard Deaggregation." Earthquake Spectra 34, no. 4 (November 2018): 1893–912. http://dx.doi.org/10.1193/080117eqs149m.
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Deaggregation is one of the products of probabilistic seismic hazard analysis (PSHA) suitable for identifying the relative contributions of various magnitude-distance bins to a hazard or intensity measure (IM) level. In this paper, we elucidate some interesting features of deaggregations, such as: their monotonically decreasing nature with IM; their invariance to any minimum IM level; and the pertinence of their bins to a complementary cumulative distribution function (CCDF). We use these features of hazard deaggregation along with copula functions in a simplified method for computing vector deaggregation and vector hazard given the scalar counterparts. We validate our simplified procedure at a hypothetical site surrounded by multiple fault sources where seismic hazard is calculated using a logic tree. We also demonstrate the application of our approach to a real site in Los Angeles, CA. Finally, we explore whether the invariance property of deaggregations can be used to compute scalar hazard curves using new ground motion prediction models/IMs, and find that for low to moderate levels of IM, a reasonable approximation is obtained.
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Chernova, Oksana, and Alexander Kukush. "Testing Linear and Nonlinear Hypotheses in a Cox Proportional Hazards Model with Errors in Covariates." Lietuvos statistikos darbai 58, no. 1 (December 20, 2019): 39–47. http://dx.doi.org/10.15388/ljs.2019.16669.
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We investigate linear and nonlinear hypotheses testing in a Cox proportional hazards model for right-censored survival data when the covariates are subject to measurement errors. In Kukush and Chernova (2018) [Theor. Probability and Math. Statist. 96, 101–110], a consistent simultaneous estimator is introduced for the baseline hazard rate and the vector of regression parameters. Therein the baseline hazard rate belongs to an unbounded set of nonnegative Lipschitz functions, with fixed constant, and the vector of regression parameters belongs to a compact parameter set. Based on the estimator, we develop two procedures to test nonlinear and linear hypotheses about the vector of regression parameters: Wald-type and score-type tests. The latter is based on an unbiased estimating equation. The consistency of the tests is shown.
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Boland, Philip J., Emad El-Neweihi, and Frank Proschan. "Applications of the hazard rate ordering in reliability and order statistics." Journal of Applied Probability 31, no. 1 (March 1994): 180–92. http://dx.doi.org/10.2307/3215245.
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The hazard rate ordering is an ordering for random variables which compares lifetimes with respect to their hazard rate functions. It is stronger than the usual stochastic order for random variables, yet is weaker than the likelihood ratio ordering. The hazard rate ordering is particularly useful in reliability theory and survival analysis, owing to the importance of the hazard rate function in these areas. In this paper earlier work on the hazard rate ordering is reviewed, and extensive new results related to coherent systems are derived. Initially we fix the form of a coherent structure and investigate the effect on the hazard rate function of the system when we switch the lifetimes of its components from the vector (T1, · ··, Tn) to the vector (T′1, · ··, T′n), where the hazard rate functions of the two vectors are assumed to be comparable in some sense. Although the hazard rate ordering is closed under the formation of series systems, we see that this is not the case for parallel systems even when the system is a two-component parallel system with exponentially distributed lifetimes. A positive result shows that for two-component parallel systems with proportional hazards (λ1r(t), λ2r(t))), the more diverse (λ1, λ2) is in the sense of majorization the stronger is the system in the hazard rate ordering. Unfortunately even this result does not extend to parallel systems with more than two components, demonstrating again the delicate nature of the hazard rate ordering.The principal result of the paper concerns the hazard rate ordering for the lifetime of a k-out-of-n system. It is shown that if τ k|n is the lifetime of a k-out-of-n system, then τ k|n is greater than τ k+1|n in the hazard rate ordering for any k. This has an interesting interpretation in the language of order statistics. For independent (not necessarily identically distributed) lifetimes T1, · ··, Tn, we let Tk:n represent the kth order statistic (in increasing order). Then it is shown that Tk +1:n is greater than Tk:n in the hazard rate ordering for all k = 1, ···, n − 1. The result does not, however, extend to the stronger likelihood ratio order.
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Mavrouli, Maria, Spyridon Mavroulis, Efthymios Lekkas, and Athanassios Tsakris. "Infectious Diseases Associated with Hydrometeorological Hazards in Europe: Disaster Risk Reduction in the Context of the Climate Crisis and the Ongoing COVID-19 Pandemic." International Journal of Environmental Research and Public Health 19, no. 16 (August 17, 2022): 10206. http://dx.doi.org/10.3390/ijerph191610206.
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Hydrometeorological hazards comprise a wide range of events, mainly floods, storms, droughts, and temperature extremes. Floods account for the majority of the related disasters in both developed and developing countries. Flooding alters the natural balance of the environment and frequently establish a favorable habitat for pathogens and vectors to thrive. Diseases caused by pathogens that require vehicle transmission from host to host (waterborne) or a host/vector as part of their life cycle (vector-borne) are those most likely to be affected by flooding. Considering the most notable recent destructive floods events of July 2021 that affected several Central Europe countries, we conducted a systematic literature review in order to identify documented sporadic cases and outbreaks of infectious diseases in humans in Europe, where hydrometeorological hazards, mainly floods, were thought to have been involved. The occurrence of water-, rodent-, and vector-borne diseases in several European countries is highlighted, as flooding and the harsh post-flood conditions favor their emergence and transmission. In this context, strategies for prevention and management of infectious disease outbreaks in flood-prone and flood-affected areas are also proposed and comprise pre- and post-flood prevention measures, pre- and post-outbreak prevention measures, as well as mitigation actions when an infectious disease outbreak finally occurs. Emphasis is also placed on the collision of floods, flood-related infectious disease outbreaks, and the evolving COVID-19 pandemic, which may result in unprecedented multi-hazard conditions and requires a multi-hazard approach for the effective disaster management and risk reduction.
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Franklinos, Lydia H. V., David W. Redding, Tim C. D. Lucas, Rory Gibb, Ibrahim Abubakar, and Kate E. Jones. "Joint spatiotemporal modelling reveals seasonally dynamic patterns of Japanese encephalitis vector abundance across India." PLOS Neglected Tropical Diseases 16, no. 2 (February 22, 2022): e0010218. http://dx.doi.org/10.1371/journal.pntd.0010218.
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Predicting vector abundance and seasonality, key components of mosquito-borne disease (MBD) hazard, is essential to determine hotspots of MBD risk and target interventions effectively. Japanese encephalitis (JE), an important MBD, is a leading cause of viral encephalopathy in Asia with 100,000 cases estimated annually, but data on the principal vector Culex tritaeniorhynchus is lacking. We developed a Bayesian joint-likelihood model that combined information from available vector occurrence and abundance data to predict seasonal vector abundance for C. tritaeniorhynchus (a constituent of JE hazard) across India, as well as examining the environmental drivers of these patterns. Using data collated from 57 locations from 24 studies, we find distinct seasonal and spatial patterns of JE vector abundance influenced by climatic and land use factors. Lagged precipitation, temperature and land use intensity metrics for rice crop cultivation were the main drivers of vector abundance, independent of seasonal, or spatial variation. The inclusion of environmental factors and a seasonal term improved model prediction accuracy (mean absolute error [MAE] for random cross validation = 0.48) compared to a baseline model representative of static hazard predictions (MAE = 0.95), signalling the importance of seasonal environmental conditions in predicting JE vector abundance. Vector abundance varied widely across India with high abundance predicted in northern, north-eastern, eastern, and southern regions, although this ranged from seasonal (e.g., Uttar Pradesh, West Bengal) to perennial (e.g., Assam, Tamil Nadu). One-month lagged predicted vector abundance was a significant predictor of JE outbreaks (odds ratio 2.45, 95% confidence interval: 1.52–4.08), highlighting the possible development of vector abundance as a proxy for JE hazard. We demonstrate a novel approach that leverages information from sparse vector surveillance data to predict seasonal vector abundance–a key component of JE hazard–over large spatial scales, providing decision-makers with better guidance for targeting vector surveillance and control efforts.
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Boland, Philip J., Emad El-Neweihi, and Frank Proschan. "Applications of the hazard rate ordering in reliability and order statistics." Journal of Applied Probability 31, no. 01 (March 1994): 180–92. http://dx.doi.org/10.1017/s0021900200107430.
Full textAbstract:
The hazard rate ordering is an ordering for random variables which compares lifetimes with respect to their hazard rate functions. It is stronger than the usual stochastic order for random variables, yet is weaker than the likelihood ratio ordering. The hazard rate ordering is particularly useful in reliability theory and survival analysis, owing to the importance of the hazard rate function in these areas. In this paper earlier work on the hazard rate ordering is reviewed, and extensive new results related to coherent systems are derived. Initially we fix the form of a coherent structure and investigate the effect on the hazard rate function of the system when we switch the lifetimes of its components from the vector (T 1, · ··, Tn ) to the vector (T′ 1, · ··, T′n ), where the hazard rate functions of the two vectors are assumed to be comparable in some sense. Although the hazard rate ordering is closed under the formation of series systems, we see that this is not the case for parallel systems even when the system is a two-component parallel system with exponentially distributed lifetimes. A positive result shows that for two-component parallel systems with proportional hazards (λ 1 r(t), λ 2 r(t))), the more diverse (λ 1, λ2 ) is in the sense of majorization the stronger is the system in the hazard rate ordering. Unfortunately even this result does not extend to parallel systems with more than two components, demonstrating again the delicate nature of the hazard rate ordering. The principal result of the paper concerns the hazard rate ordering for the lifetime of a k-out-of-n system. It is shown that if τ k|n is the lifetime of a k-out-of-n system, then τ k|n is greater than τ k+ 1|n in the hazard rate ordering for any k. This has an interesting interpretation in the language of order statistics. For independent (not necessarily identically distributed) lifetimes T 1, · ··, Tn , we let Tk:n represent the kth order statistic (in increasing order). Then it is shown that Tk + 1:n is greater than Tk:n in the hazard rate ordering for all k = 1, ···, n − 1. The result does not, however, extend to the stronger likelihood ratio order.
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Navarro, Jorge, and Moshe Shaked. "Hazard rate ordering of order statistics and systems." Journal of Applied Probability 43, no. 2 (June 2006): 391–408. http://dx.doi.org/10.1239/jap/1152413730.
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Let X = (X1, X2, …, Xn) be an exchangeable random vector, and write X(1:i) = min{X1, X2, …, Xi}, 1 ≤ i ≤ n. In this paper we obtain conditions under which X(1:i) decreases in i in the hazard rate order. A result involving more general (that is, not necessarily exchangeable) random vectors is also derived. These results are applied to obtain the limiting behaviour of the hazard rate function of the lifetimes of various coherent systems in reliability theory. The notions of the Samaniego signatures and the minimal signatures of such systems are extensively used in the paper. An interesting relationship between these two signatures is obtained. The results are illustrated in a series of examples.
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Navarro, Jorge, and Moshe Shaked. "Hazard rate ordering of order statistics and systems." Journal of Applied Probability 43, no. 02 (June 2006): 391–408. http://dx.doi.org/10.1017/s0021900200001716.
Full textAbstract:
LetX= (X1,X2, …,Xn) be an exchangeable random vector, and writeX(1:i)= min{X1,X2, …,Xi}, 1 ≤i≤n. In this paper we obtain conditions under whichX(1:i)decreases iniin the hazard rate order. A result involving more general (that is, not necessarily exchangeable) random vectors is also derived. These results are applied to obtain the limiting behaviour of the hazard rate function of the lifetimes of various coherent systems in reliability theory. The notions of the Samaniego signatures and the minimal signatures of such systems are extensively used in the paper. An interesting relationship between these two signatures is obtained. The results are illustrated in a series of examples.
Dissertations / Theses on the topic "Hazard vector"
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Young, Stephen. "Efficacy and understanding of the safety hierarchy of controls." Thesis, Federation University Australia, 2017. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/165610.
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This document constitutes the submission of Stephen Young for the degree of Doctor of Philosophy at Federation University Australia. The submission is offered as a thesis by publication – representing a summary of the candidate’s research based around a number of already-published peer-reviewed papers, supported by additional analysis and commentary. The research project is entitled “Efficacy and Understanding of the Safety Hierarchy of Controls”. The key question posed in this thesis is stated as: “What constrains understanding of the efficacy of the safety hierarchy?” This question was broken down into three sub-questions, each of which is represented within this submission as Part One, Part Two, and Part Three respectively. The three questions are stated as: 1. How may contemporary evidence demonstrate the efficacy of the safety hierarchy? 2. What are the constraints on understanding the hazard vector as it relates to the safety hierarchy? 3. What is the current understanding of hazard mitigation in a selected industry and how may the safety hierarchy be implemented to ameliorate a key hazard? The Introduction indicates the importance of the topic and explains the background to the concept known as the [safety] hierarchy of control, including a distinction between hazard and risk. It then undertakes a brief review of the development of twentieth century safety literature, including a consideration of how safety analysis has been split into the energy damage model and the anthropocentric model – complicated by a persistence of myth and superstition. An update of more recent safety literature in the twenty-first century and literature relating to governance decision making is also included. The intended contribution of this research project is laid out along with an explanation of how the thesis is organised. Part One seeks to use contemporary evidence to demonstrate the efficacy of the safety hierarchy. This is primarily achieved by presenting two case studies predominantly focussed on a New Zealand aluminium smelter. The first paper, “From zero to hero: A case study of industrial injury reduction”, used the candidate’s earlier research documenting that company’s remarkable journey from a worksite with an unenviably high level of injuries to that of one of the safest industrial worksites in the world. It contextualised the research within the contemporary zero accident vision (ZAV) and considered the company’s use of the hierarchy of controls as a primary means of hazard intervention. This paper was published in Safety Science in 2014. A further study was conducted later in 2014 to qualitatively consider the effect on safety of the difficult economic times being experienced by the aluminium industry. This purposive critical case study revisited the New Zealand aluminium smelter to document the observations of safety managers as they sought to continue the company’s exemplary safety record in the face of financial duress. “Safety in hard times: A qualitative analysis of safety concerns in two industrial plants under financial duress” also included parallel observations of safety managers from an Australian aluminium rolling mill as it closed down in response to the same economic factors. The impact of lean management and the ongoing efficacy of hierarchy of controls methodology within both plants was documented and considered. This paper was published in Safety Science in 2018. Insofar as is possible using case studies, both papers demonstrated the efficacy of the hierarchy of control as an intervention methodology for ameliorating hazards in the workplace. Part Two seeks to consider the constraints on understanding the hazard vector as it relates to the hierarchy of controls. A focussed literature review entitled “The root cause fallacy” was conducted to better understand the uses of the word cause in philosophy, law, and science – as well as in the applied science of safety management. This paper highlighted the limitations of the concept of root cause as a safety intervention precept; thereby identifying a significant constraint on understanding the hazard vector and the hierarchy of control. This is followed by a chapter deconstructing the most common version of the hierarchy of controls, pointing out how it could be made easier to understand and proposing a simplified version – more aligned to the underlying hazard vector. This alignment has been successfully presented in a number a conferences including the proceedings of 2014 Australian Systems Safety Conference; and ultimately, to the 15th World Congress on Public Health in 2017. Part Three applies the knowledge gained in Parts One and Two, and presents two studies investigating the fermentation industry to both understand the role of the hierarchy of controls in hazard mitigation and to illustrate how it can be more effectively implemented. The first paper took the potentially catastrophic hazard of asphyxiation from elevated levels of carbon dioxide (CO2) and demonstrated how the hierarchy of controls could be applied to more effectively control the hazard. The second paper surveyed the rapidly growing boutique beer industry in Victoria and Tasmania to understand how hazards were being managed, and the degree to which the hierarchy of controls was used to ameliorate the identified hazards. Together, these papers illustrated that application of the hierarchy of controls is largely conspicuous by its absence in the mitigation of hazards in a rapidly growing industry; while also demonstrating an effective hierarchal control that could evade an almost inevitable looming catastrophe. In conclusion, this thesis demonstrates the efficacy of the hierarchy of controls in Part One. In Part Two, it considers the linguistic origin of the word cause and consequently reconsiders the hazard vector insofar as it relates to the hierarchy of controls – incorporating these findings into a simpler and more easily understood hierarchy. Part Three provides a demonstration of how the hierarchy of controls can be applied to a difficult hazard in an emerging industry and also highlights the contemporary deficiencies in how that industry currently deals with the hazards they identify. Finally, the key question “What constrains understanding of the efficacy of the safety hierarchy?” is addressed by summarising the three parts of this thesis and concluding: 1. An assiduous application of the hierarchy of controls can prevent occupational injuries. 2. The efficacy of the hierarchy of controls is constrained by the following factors: a. Over-complication of what is a simple concept; b. Misunderstanding of how hazard interventions may be used to prevent injury; c. Misunderstanding of the construct of cause as it relates to the hazard vector. 3. Appropriate recognition of the relative significance of identified hazards is central to the understanding of the safety hierarchy.Doctor of Philosophy
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Salfeld, Thomas [Verfasser]. "Stochastic mortality modelling with cointegrated vector autoregressive processes and characterizations of logistic-type hazard rate distributions / Thomas Salfeld." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1176105248/34.
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Leech, S. L. "Investigation into the vector competence of Ixodes ricinus ticks to Hazara virus and Crimean-Congo Haemorrhagic Fever virus." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2015. http://researchonline.lshtm.ac.uk/2212902/.
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Tick-borne pathogens represent a large threat to the UK and International Public Health authorities. Due to recent changes in legislation, an increase in animal & human movements and changing climate, the UK may now be at an increased risk of importing exotic tick species and their associated pathogens. It is vital to assess the susceptibility of UK tick species to these highly fatal tick-borne viral zoonoses. To date, studies investigating the interaction of many pathogens with their vectors have been hindered due to the lack of a suitable tick transmission model at high containment. This thesis investigates the intrinsic ability of Ixodes ricinus, the most widely distributed tick in Europe and the UK, to acquire, replicate and transmit both Hazara virus (HAZV, a hazard group 2 surrogate for CCHFV) and Crimean–Congo haemorrhagic fever virus (a hazard group 4 pathogen) addressing their potential to act as competent vectors. During the last decade CCHFV has emerged in new areas within Europe and the principle tick vector of CCHFV has been detected within the UK. The development of methods for use with ticks and highly pathogenic viruses within ticks was an essential part of this work. Firstly techniques for the handling, extraction and storage of RNA obtained from I. ricinus ticks were optimised and different endogenous controls were assessed for their ability to amplify mRNA transcripts for use as endogenous controls. The use of the immersion technique for use with I. ricinus nymphs was optimised and working procedures and protocols for handling ticks at containment level 2 and 4 were established. Ixodes ricinus nymphs are susceptible to infection with HAZV with 100% becoming infected 13 days post-immersion. HAZV was able to establish itself within the key target organs of the tick midgut and salivary glands, produce infectious virus particles and transmit virus to 38% of mice. This artificial method of inoculation was optimised for use within the CL4 environment and was used to show that I. ricinus nymphs were not susceptible to CCHFV via immersion. In addition to horizontal transmission, I. ricinus ticks also demonstrated vertical transmission of HAZV through to the adult stage. This is the first time I. ricinus ticks have been assessed for their susceptibility to HAZV and CCHFV and their use in establishing the first high containment In vivo tick feeding model in Europe.
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Pinto, Jayme Augusto Duarte Pereira. "Aprofundando as noções de dependência e envelhecimento em distribuições bivariadas de probabilidade." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/45/45133/tde-22042014-190441/.
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A distribuição bivariada de Marshall-Olkin é estendida, relaxando-se a hipótese de choques exponencialmente distribuídos e assumindo-se dependência entre os choques individuais. Abordagem semelhante é considerada para sua versão dual. Representação por meio de cópula, propriedades probabilísticas e de confiabilidade assim como resultados em valores extremos são então obtidos. A propriedade de falta de memória bivariada é estendida assumindo-se uma função de dependência sem memória. Uma nova classe de distribuições caracterizada por essa propriedade estendida é introduzida. Correspondentes interpretações geométricas, procedimentos de construção, representação estocástica, relação com cópula de sobrevivência e propriedades de confiabilidade são derivadas.Bivariate Marshall-Olkin model, Dual model, Exponential representation, Dependence function, Bivariate aging, Copula, Survival copula, Stochastic order, Bivariate extreme value distribution, Pickands measure, Pickands dependence function, Failure rate, Bivariate hazard gradient, Bivariate lack-of-memory, Residual lifetime vector, Characterization.
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Δημήτριος, Ρούλιας. "Methodologies for remaining useful life estimation with multiple sensors in rotating machinery." Thesis, 2014. http://hdl.handle.net/10889/8258.
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The focus of this thesis was the development of failure prognosis methods (prognostics) in rotating machinery with use of multiple sensors digital signal processing and machine learning techniques. The motivation stems from the void in literature concerning prognostics in meshing gearboxes. Moreover, there are several but inconclusive works regarding bearing prognosis.
Few research groups have studied multi-hour fatigue gear experiments and this was one of the contributions of this thesis. Moreover, the study expanded beyond the sheer application of vibration monitoring with the addition of an Oil Debris Monitoring probe (ODM) as well as Acoustic emission (AE).
The method of AE monitoring is, once again, proposed as a robust technique for failure prognosis being better correlated with gear pitting level compared to the classic vibration monitoring technique. Moreover, judging from ODM recordings the gear pitting comprises of two phases i) a linear phase, with an almost constant pitting rate and ii) a very short non linear phase where the pitting rate increases exponentially, an explicit indication of a critical failure.
Multi-hour gear experiments that are close to real scale applications are very demanding in time as well as in invested capital. To bypass this shortfall a gear failure like simulation is proposed. The simulation framework is based on real life experiments and is applied to assess a number of data-driven Remaining Useful Life (RUL) estimation techniques namely i) Proportional Hazards Μodel (PHM), ii) ε- Support Vector Regression ε-SVR and iii) Exponential extrapolation based on bootstrap sampling.
In the current thesis a feature extraction scheme for prognosis is proposed and assessed based on time domain, frequency domain statistical features and Wavelet Packet (WP) energy derived from AE and vibration recordings. ICA is proposed as a preferable fusion technique for gear failure prognostics. Application of ICA for feature fusion provided a clear improvement regarding the earlier presented bootstrap extrapolation technique.
Bearings are also taken into account since they are closely connected to gearboxes. In the current thesis a wavelet denoising method is proposed for bearing vibration recordings aiming to the improvement of the diagnostic and prognostic potential of vibration. Finally the importance of data fusion is highlighted in the case of bearings. It is observed that a feature extraction scheme can generalize the application of prognostics, even in cases where RMS may yield no important degradation trend.Η παρούσα εργασία εστιάζεται στην ανάπτυξη μεθοδολογιών πρόβλεψης τελικής αστοχίας σε περιστρεφόμενα συστήματα με χρήση πολλαπλών αισθητήρων και μεθόδων μηχανικής μάθησης και επεξεργασίας σήματος. Το κίνητρο προήλθε από το κενό που υπάρχει στη βιβλιογραφία όσον αφορά την προγνωστική σε κιβώτια ταχυτήτων. Η προγνωστική σε έδρανα έχει μεν μελετηθεί αλλά σε μικρό βαθμό και η παρούσα εργασία έρχεται να συμβάλλει και σε αυτό τον τομέα. Στα πλαίσια αυτής της εργασίας εκπονήθηκε ένας αριθμός πειραμάτων κόπωσης κιβωτίων ταχυτήτων. Η μελέτη επεκτάθηκε πέραν της παρακολούθησης κατάστασης με τη μέθοδο των κραδασμών και συγκεκριμένα μελετήθηκαν καταγραφές σωματιδίων σιδήρου στο λιπαντικό (ODM) καθώς και Ακουστική Εκπομπής (AE). Η μέθοδος ΑΕ ευρέθη πιο στενά συσχετισμένη με τη σταδιακή υποβάθμιση της ακεραιότητας του κιβωτίου ταχυτήτων σε σχέση με τις καταγραφές κραδασμών. Επίσης με βάση τις καταγραφές του αισθητήρα σωματιδίων σιδήρου διακρίθηκαν δύο στάδια υποβάθμισης i) μια γραμμική περιοχή με σχεδόν σταθερό ρυθμό απελευθέρωσης υλικού από την επιφάνεια των δοντιών και ii) μια σύντομη αλλά έντονα μη γραμμική αύξηση στο ρυθμό αυτό πολύ κοντά στο τέλος της λειτουργίας του κιβωτίου. Tα πολύωρα πειράματα κόπωσης σε γρανάζια είναι πολύ απαιτητικά. Για να παρακαμφθεί αυτή η δυσκολία αναπτύχθηκε ένα φαινομενολογικό μοντέλο για αναπαραγωγή χρονοσειρών που ομοιάζουν σε καταγραφές γραναζιών σε κόπωση. Το μοντέλο αυτό στηρίχθηκε σε πραγματικά πειράματα κόπωσης. Έτσι έγινε δυνατό να εξεταστούν και να συγκριθούν ένας αριθμός μεθοδολογιών εκτίμησης εναπομένουσας ζωής και συγκεκριμένα i) Proportional Hazards Model (PHM), ii) ε- Support Vector Regression ε-SVR και iii) Exponential extrapolation βασισμένο σε μια διαδικασία bootstrap sampling. Στην παρούσα μελέτη προτείνεται ένα σύνολο παραμέτρων προερχόμενο από το πεδίο της συχνότητας, του χρόνου και κυματοπακέτων. Αυτό, συνδυαζόμενο με μια διαδικασία σύμπτυξης δεδομένων (ανάλυση σε πρωταρχικές και ανεξάρτητες συνιστώσες) αξιοποιείται για πρόγνωση σε γρανάζια σε κόπωση. Η τεχνική ανεξάρτητων συνιστωσών προτείνεται σαν προτιμότερη από τη σκοπιά της προγνωστικής καθώς βελτιώνει την εκτίμηση της εναπομένουσας ζωής. Η εργασία επεκτάθηκε και σε έδρανα κύλισης. Προτάθηκε μια διαδικασία wavelet denoising η οποία ενισχύει τόσο τη διαγνωστική όσο και την προγνωστική δυνατότητα του αισθητήρα κραδασμών. Τέλος, η σημασία της εξαγωγής παραμέτρων υπογραμμίζεται και στην περίπτωση της προγνωστικής σε έδρανα. Συνδυάζοντας πολλαπλές παραμέτρους και αισθητήρες κραδασμών μαζί με ένα μοντέλο ε-SVR παρέχεται ένα ολοκληρωμένο μοντέλο πιθανοτικής εκτίμησης εναπομένουσας ζωής σε έδρανα κύλισης ακόμα και σε περιπτώσεις που η τιμή RMS των κραδασμών δεν παρέχει πληροφορία.
Books on the topic "Hazard vector"
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Russi, Mark. Biological Hazards. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190662677.003.0016.
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This chapter describes various biological hazards and their impact on workers and others. A major focus of the chapter is biological hazards in healthcare and laboratory settings, including exposure to bloodborne pathogens and prevention of diseases related to them. Sections deal with sharps injuries, HIV/AIDS, hepatitis B virus, hepatitis C virus, tuberculosis, and other infectious diseases that can be acquired in the work environment via direct contact, droplet or airborne spread, or fecal-oral transmission. In addition, infectious agents spread by animal contact or arthropod vectors in a broad range of settings will be addressed. Newly emerging infectious or re-emerging infections, such as those due to H5N1 and novel H1N1 influenza, Middle Eastern respiratory syndrome (MERS), and Ebola Virus Disease (EVD) as well as agents associated with bioterrorism are discussed.
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Gibson, W. African trypanosomosis. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780198570028.003.0049.
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The African trypanosomoses are diseases of both man and his livestock. There are two forms of human trypanosomosis or sleeping sickness: Gambian or Rhodesian sleeping sickness, roughly corresponding to a West, Central or East African distribution respectively. Gambian sleeping sickness runs a more protracted and chronic course than the Rhodesian form; nevertheless, human trypanosomosis is invariably fatal if not treated. Animal reservoir hosts, both wild and domestic, assume greater importance for Rhodesian sleeping sickness than Gambian sleeping sickness, and the former is often an occupational hazard of those visiting or working in wildlife areas, e.g. tourists, hunters. Animal trypanosomosis transmitted by tsetse is generally referred to as Nagana, while the disease transmitted by other bloodsucking flies outside the African tsetse belt is known chiefly as Surra, but also by a variety of local names.Sleeping sickness control measures are aimed either at the trypanosome or the fly. Human cases are detected by active or passive surveillance and cured by treatment with trypanocidal drugs.Control of the tsetse vector is by application of residual insecticides or bush clearing and, more recently, by traps or insecticide-impregnated targets, or by wholesale release of sterile males. Tsetse control is more widely employed for the control of animal trypanosomosis than sleeping sickness.
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Monsutti, Alessandro. Afterword. University of California Press, 2017. http://dx.doi.org/10.1525/california/9780520294134.003.0013.
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Building on the case of the Hazaras, this afterword addresses some transversal themes to the whole edited volume. Articulated around the evocation of past injustices and protests against exploitation, Shiism has been the main language of political mobilization among the Hazaras in the last decades. It has been both a tool of resistance against central power in Kabul and of domination within Hazarajat. This process is only one example showing how multiple has been Islam across time and space. Sufism, state-sponsored Shari‘a courts, transnational circulation of knowledge and networks of activists, women’s religiosity are all facets of how Islam has been experienced in Afghanistan. Islam has been a mean to legitimize central power but also a vector of rebellion; it may have been a unifying factor but has also been used to create boundaries between groups.
Book chapters on the topic "Hazard vector"
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Chauhan, Shivani, Pradip Yadav, Prashant Tiwari, S. H. Upadhyay, and Niraj Mishra. "Performance Prediction of Rolling Element Bearing with Utilization of Support Vector Regression." In Reliability, Safety and Hazard Assessment for Risk-Based Technologies, 535–43. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-9008-1_44.
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van Wieren, Sipke E., Marieta A. H. Braks, and Joost Lahr. "19. Effectiveness and environmental hazards of acaricides applied to large mammals for tick control." In Ecology and Control of Vector-borne Diseases, 265–78. The Netherlands: Wageningen Academic Publishers, 2016. http://dx.doi.org/10.3920/978-90-8686-838-4_19.
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Hegg, Christopher, and Hans Kienholz. "Determining Paths of Gravity-Driven Slope Processes: The ‘Vector Tree Model’." In Geographical Information Systems in Assessing Natural Hazards, 79–92. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8404-3_5.
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Detti, Riccardo, and Valdo Pasqui. "Vector and Raster Structures in Generating Drainage-Divide Networks from Digital Terrain Models." In Geographical Information Systems in Assessing Natural Hazards, 35–55. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8404-3_3.
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Marathe, Nachiket P., and Michael S. Bank. "The Microplastic-Antibiotic Resistance Connection." In Microplastic in the Environment: Pattern and Process, 311–22. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-78627-4_9.
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AbstractMicroplastic pollution is a big and rapidly growing environmental problem. Although the direct effects of microplastic pollution are increasingly studied, the indirect effects are hardly investigated, especially in the context of spreading of disease and antibiotic resistance genes, posing an apparent hazard for human health. Microplastic particles provide a hydrophobic surface that provides substrate for attachment of microorganisms and readily supports formation of microbial biofilms. Pathogenic bacteria such as fish pathogens Aeromonas spp., Vibrio spp., and opportunistic human pathogens like Escherichia coli are present in these biofilms. Moreover, some of these pathogens are shown to be multidrug resistant. The presence of microplastics is known to enhance horizontal gene transfer in bacteria and thus, may contribute to dissemination of antibiotic resistance. Microplastics can also adsorb toxic chemicals like antibiotics and heavy metals, which are known to select for antibiotic resistance. Microplastics may, thus, serve as vectors for transport of pathogens and antibiotic resistance genes in the aquatic environment. In this book chapter, we provide background information on microplastic biofouling (“plastisphere concept”), discuss the relationship between microplastic and antibiotic resistance, and identify knowledge gaps and directions for future research.
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"C34: Pathogens—Vector Hazard." In Emergency Action for Chemical and Biological Warfare Agents, 240–45. Routledge, 2017. http://dx.doi.org/10.1201/b19083-39.
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Kahime, Kholoud, Moulay Abdelmonaim El Hidan, Denis Sereno, Bounoua Lahouari, Ahmed Karmaoui, Abdellaziz Ait Mansour, Nadia Zouhairi, Hind Benammi, and Khalid Elkalay. "Vector Borne Diseases and Climate Change." In Advances in Environmental Engineering and Green Technologies, 349–58. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7775-1.ch017.
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The incidence of emergence diseases including vector borne diseases, water diseases, and some physiologic impairment is considered sensitive to climate. Malaria, leishmaniasis, dengue, and viral encephalitis are among those diseases most influenced by climate. Variation in the incidence of vector borne diseases is associated with extreme weather events and annual changes in weather conditions. Africa in general and Morocco in particular are designated as an area of significant impact by numerous the Intergovernmental Panel on Climate Change (IPCC) reports and notably susceptible to such drastic climate-related health consequences. Climatic parameter change would directly affect disease transmission by acting on the vector's geographic range, activity, or reproduction and by reduction the period of pathogen incubation. This chapter will discuss the increasing risk of some vector-borne diseases in hazard-prone localities. It further identifies the severe challenges both of health adaptation to climate change by highlighting Moroccan adaptive capacity to such crises.
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Kahime, Kholoud, Moulay Abdelmonaim El Hidan, Denis Sereno, Bounoua Lahouari, Ahmed Karmaoui, Abdellaziz Ait Mansour, Nadia Zouhairi, Hind Benammi, and Khalid Elkalay. "Vector Borne Diseases and Climate Change." In Research Anthology on Environmental and Societal Impacts of Climate Change, 2029–38. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-3686-8.ch102.
Full textAbstract:
The incidence of emergence diseases including vector borne diseases, water diseases, and some physiologic impairment is considered sensitive to climate. Malaria, leishmaniasis, dengue, and viral encephalitis are among those diseases most influenced by climate. Variation in the incidence of vector borne diseases is associated with extreme weather events and annual changes in weather conditions. Africa in general and Morocco in particular are designated as an area of significant impact by numerous the Intergovernmental Panel on Climate Change (IPCC) reports and notably susceptible to such drastic climate-related health consequences. Climatic parameter change would directly affect disease transmission by acting on the vector's geographic range, activity, or reproduction and by reduction the period of pathogen incubation. This chapter will discuss the increasing risk of some vector-borne diseases in hazard-prone localities. It further identifies the severe challenges both of health adaptation to climate change by highlighting Moroccan adaptive capacity to such crises.
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Bazzurro, P., and J. Park. "Vector-valued probabilistic seismic hazard analysis of correlated ground motion parameters." In Applications of Statistics and Probability in Civil Engineering, 1596–603. CRC Press, 2011. http://dx.doi.org/10.1201/b11332-237.
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Tanaka, K., and T. Takada. "Vector-valued probabilistic seismic hazard analysis using the seismic wave inventory." In Life-Cycle of Civil Engineering Systems, 2103–8. CRC Press, 2014. http://dx.doi.org/10.1201/b17618-312.
Full textConference papers on the topic "Hazard vector"
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Dhulipala, Somayajulu L. N., Adrian Rodriguez-Marek, and Madeleine M. Flint. "Salient Features of Seismic Hazard Deaggregation and Computation of Vector Hazard." In Geotechnical Earthquake Engineering and Soil Dynamics V. Reston, VA: American Society of Civil Engineers, 2018. http://dx.doi.org/10.1061/9780784481462.016.
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Yuan, Lifeng, Qingfeng Zhang, Wenwen Li, and Lanjun Zou. "Debris Flow Hazard Assessment Based on Support Vector Machine." In 2006 IEEE International Symposium on Geoscience and Remote Sensing. IEEE, 2006. http://dx.doi.org/10.1109/igarss.2006.1083.
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Negro, Cira Del, Eleonora Amato, Federica Torrisi, Claudia Corradino, Maide Bucolo, and Luigi Fortuna. "Support Vector Machine for volcano hazard monitoring from space at Mount Etna." In 2022 IEEE 21st Mediterranean Electrotechnical Conference (MELECON). IEEE, 2022. http://dx.doi.org/10.1109/melecon53508.2022.9842942.
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Glenn Wright, R., and Cheryl M. Zimmerman. "Vector data extraction from forward-looking sonar imagery for hydrographic survey and hazard to navigation detection." In OCEANS 2015 - MTS/IEEE Washington. IEEE, 2015. http://dx.doi.org/10.23919/oceans.2015.7401889.
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Xu, Yaosong, Rixin Ren, Shuyue Wang, and Zhizhong Wang. "Prediction of Rock Burst Hazard Level Based on Improved Whale Optimization Algorithm—Least Square Support Vector Machine (IWOA-LSSVM)." In 2022 2nd International Conference on Electrical Engineering and Mechatronics Technology (ICEEMT). IEEE, 2022. http://dx.doi.org/10.1109/iceemt56362.2022.9862701.
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Melissianos, Vasileios E., Dimitrios Vamvatsikos, and Charis J. Gantes. "Probabilistic Assessment of Innovative Mitigating Measures for Buried Steel Pipeline–Fault Crossing." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45345.
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A methodology is presented on assessing the effectiveness of flexible joints in mitigating the consequences of faulting on buried steel pipelines through a comprehensive analysis that incorporates the uncertainty of fault displacement magnitude and the response of the pipeline itself. The proposed methodology is a two-step process. In the first step the probabilistic nature of the fault displacement magnitude is evaluated by applying the Probabilistic Fault Displacement Hazard Analysis, considering also all pertinent uncertainties. The second step is the “transition” from seismological data to the pipeline structural response through the fault displacement components as the adopted vector intensity measure. To mitigate the consequences of faulting on pipelines, flexible joints between pipeline parts are proposed as innovative measure for reducing the deformation of pipeline walls. Thus, the mechanical behavior of continuous pipelines and pipelines with flexible joints is numerically assessed and strains are extracted in order to develop the corresponding strain hazard curves. The latter are a useful engineering tool for pipeline – fault crossing risk assessment and for the effectiveness evaluation of flexible joints as innovative mitigating measures against the consequences of faulting on pipelines.
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Bykov, Valentyn, Jiři Křepel, and Andreas Pautz. "Molten Salt Fast Reactor Blanket Design and Proliferation Resistance Assessment." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-31026.
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Molten Salt Reactor (MSR) designs are frequently accompanied by a blanket salt. This way the irradiation of the outer reactor wall will be strongly reduced. On the other hand, the barrier between the core and blanket will undergo higher irradiation and it will be necessary to replace it several times during the reactor lifetime. Furthermore, this blanket salt will also have a positive impact on neutron economy by improving the breeding performance. In this paper a blanket of a generic two fluid molten salt reactor utilizing fast thorium-uranium cycle was investigated. This was done by tracking the evolution of uranium, neptunium and plutonium isotopes with burnup, which was then influenced by removal of uranium from the blanket. A significant reduction in the production of minor actinides was observed. The uranium vector removed from the core was then investigated for proliferation resistance, using NUREC proliferation resistance metric and comparison with other weapon designs. The evaluation concluded that while the presence of U-232 increases radiological hazard associated with this uranium, thereby erecting a radiological barrier, it cannot be treated as “self-protecting” based on IAEA and NRC standards, requiring 1 Sv/h at 1m dose rate. Moreover ideas on how an interested party could reduce this radiological hazard were discussed.
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Sajedi, Seyed Omid, and Xiao Liang. "Intensity-Based Feature Selection for Near Real-Time Damage Diagnosis of Building Structures." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.1005.
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<p>Near real-time damage diagnosis of building structures after extreme events (e.g., earthquakes) is of great importance in structural health monitoring. Unlike conventional methods that are usually time-consuming and require human expertise, pattern recognition algorithms have the potential to interpret sensor recordings as soon as this information is available. This paper proposes a robust framework to build a damage prediction model for building structures. Support vector machines are used to predict the existence as well as the probable location of the damage. The model is designed to consider probabilistic approaches in determining hazard intensity given the existing attenuation models in performance-based earthquake engineering. Performance of the model regarding accurate and safe predictions is enhanced using Bayesian optimization. The proposed framework is evaluated on a reinforced concrete moment frame. Targeting a selected large earthquake scenario, 6,240 nonlinear time history analyses are performed using OpenSees. Simulation results are engineered to extract low-dimensional intensity-based features that can be used as damage indicators. For the given case study, the proposed model achieves a promising accuracy of 83.1% to identify damage location, demonstrating the great potential of model capabilities.</p>
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Kollam, Manoj, and Ajay Joshi. "A MACHINE LEARNING MODEL FOR AN EARTHQUAKE FORECASTING USING PARALLEL PROCESSING." In International Conference on Emerging Trends in Engineering & Technology (IConETech-2020). Faculty of Engineering, The University of the West Indies, St. Augustine, 2020. http://dx.doi.org/10.47412/dhhv5862.
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Earthquake is a devastating natural hazard which has a capability to wipe out thousands of lives and cause economic loss to the geographical location. Seismic stations continuously gather data without the necessity of the occurrence of an event. The gathered data is processed by the model to forecast the occurrence of earthquakes. This paper presents a model to forecast earthquakes using Parallel processing. Machine Learning is rapidly taking over a variety of aspects in our daily lives. Even though Machine Learning methods can be used for analyzing data, in the scenario of event forecasts like earthquakes, performance of Machine Learning is limited as the data grows day by day. Using ML alone is not a perfect solution for the model. To increase the model performance and accuracy, a new ML model is designed using parallel processing. The drawbacks of ML using central processing unit (CPU) can be overcome byGraphic Processing unit (GPU) implementation, since the parallelism is naturally provided using framework for developing GPU utilizing computational algorithms, known as the Compute Unified Device Architecture (CUDA). The implementation of hybrid state vector machine (H-SVM) algorithm using parallel processing through CUDA is used to forecast earthquakes. Our experiments show that the GPU based implementation achieved typical speedup values in the range of 3-70 times compared to conventional central processing unit (CPU). Results of different experiments are discussed along with their consequences.
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HAIJIANG, LI, LI RUBIN, AO QIUHUA, WANG WEICHENG, WANG XIUFENG, DU LEILEI, WEN JUN, and ZHU LILI. "AN INTELLIGENT METHOD FOR BEARING FAULT DIAGNOSIS BASED ON IMPROVED VMD AND GSM-SVM." In 3rd International Workshop on Structural Health Monitoring for Railway System (IWSHM-RS 2021). Destech Publications, Inc., 2021. http://dx.doi.org/10.12783/iwshm-rs2021/36024.
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In industrial sites, the running state of rolling bearings is often judged by hearing the sound with human ears. This method relies on long-term accumulation of human experience and is prone to cause occupational noise hazards. To solve this problem, this paper proposed an intelligent diagnosis method for the running state of bearings based on machine hearing. Firstly, bearing vibration signal was decomposed using an improved Variational Mode Decomposition (VMD) algorithm, by which the best mode component containing the fault characteristic was determined according to a time-frequency weighted kurtosis maximization criterion. Then, the time-domain feature indexes and psychoacoustic indexes of the best mode component were calculated to define a feature vector. Finally, the feature vectors were input into a fault classification model based on Support Vector Machine optimized by Grid Search Method (GSM-SVM) for training. The trained model was used to diagnose unknown faults of bearings. The proposed method was applied to the traction motors of EMU train for automatic bearing fault diagnose. Field test in the manufacturing factory showed that it could quickly diagnose bearing faults with a high accuracy rate.