{"id":941,"date":"2022-02-14T12:49:36","date_gmt":"2022-02-14T12:49:36","guid":{"rendered":"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/?p=941"},"modified":"2022-02-17T16:35:18","modified_gmt":"2022-02-17T16:35:18","slug":"yearly-coal-mining-disasters-changepoint-detection","status":"publish","type":"post","link":"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/2022\/02\/14\/yearly-coal-mining-disasters-changepoint-detection\/","title":{"rendered":"Yearly Coal Mining Disasters &#8211; Bayesian Changepoint  Detection"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"941\" class=\"elementor elementor-941\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-2b64e47 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"2b64e47\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-29ddb77\" data-id=\"29ddb77\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-d15ad7a elementor-widget elementor-widget-heading\" data-id=\"d15ad7a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">1. Introduction<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-e1b33e3 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"e1b33e3\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-ac29473\" data-id=\"ac29473\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-35a98ba elementor-widget elementor-widget-text-editor\" data-id=\"35a98ba\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-size: 13px\">Around the world, mining disasters are the source of thousands of deaths every year. Amongst the different types of mining methods, underground coal mining is particularly dangerous. This was especially true during the 19<\/span><sup>th<\/sup><span style=\"font-size: 13px\"> century and led to the creation of the Coal Mines Regulations Act of 1887, which took effect in the United Kingdom on the 1st January 1888. Until then, it was not required to have ventilation in the mines and explosives could be stored underground, additionally, this act raised the minimal age for mine workers from 10 to 12 years old (note that until the 1840s, children as young as 5 years old took part in the industrial workforce)<a href=\"https:\/\/www.degruyter.com\/document\/doi\/10.3138\/9781487571900-003\/html\" target=\"_blank\" rel=\"noopener\"> (Tailor, 1968)<\/a>. Social science researchers may be interested in finding out if such regulations have had an impact on the yearly number of mining disasters. This can contribute to a better understanding of what causes mining disasters and thus help further reduce them.<\/span><\/p><p>The data used for this project comes from the Colliery Year Book and Coal Trades Directory available from the National Coal Board in London <a href=\"https:\/\/academic.oup.com\/biomet\/article-abstract\/66\/1\/191\/224063?redirectedFrom=fulltext\" target=\"_blank\" rel=\"noopener\">(Jarrett, 1979)<\/a>. This data contains the count of annual coal mining disasters in the UK between 1851 and 1962. The aim of this project is to detect changes in the rate of yearly coal mining disasters in the UK between 1851 and 1962 using a Bayesian approach. We are not attempting to explain why the rates have changed but simply to identify if and when they may have happened. To do so, the method used in this project is known as Bayesian changepoint detection. Using this method, models with different number of changepoints were fitted to the data. To keep the blog clear, the model for three changepoints will often be used as an example. An additional goal was to determine the model which best explains the observed data. Fitting these models required the implementation of a sampling technique; for this project we used Direct Sampling. Direct Sampling was chosen as it does not rely on convergence unlike Markov Chain Monte Carlo methods.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-42054bb elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"42054bb\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-7d45722\" data-id=\"7d45722\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-8d7fcaf elementor-widget elementor-widget-heading\" data-id=\"8d7fcaf\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">2. Results<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-23a693a elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"23a693a\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-898c39e\" data-id=\"898c39e\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-3bb70f0 elementor-widget elementor-widget-heading\" data-id=\"3bb70f0\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">2.1 The Concept of Changepoint Detection for Mining Disasters<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-eb541f6 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"eb541f6\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-027288c\" data-id=\"027288c\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-7a7acf5 elementor-widget elementor-widget-text-editor\" data-id=\"7a7acf5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-family: Poppins;font-size: 13px;font-style: normal;font-weight: 400\">Let us assume a certain event occurs exactly the same number of times every year. When plotting the cumulative number of times this event occurs against the years, we would expect to observe a straight line. The cumulative number of UK coal mining disasters between 1851 and 1962 is displayed in Figure 1. The line in this plot is not straight, hence it seems that the number of yearly coal mining disasters is not constant between 1851 and 1962. Empirically, the rate of mining disasters appears to slow down just before the beginning of the 20th century.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-db95d59 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"db95d59\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-ec6bc83\" data-id=\"ec6bc83\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-5b9f307 elementor-widget elementor-widget-image\" data-id=\"5b9f307\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"768\" height=\"439\" src=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/cumdisasters-768x439.png\" class=\"attachment-medium_large size-medium_large wp-image-951\" alt=\"Cumdisasters\" srcset=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/cumdisasters-768x439.png 768w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/cumdisasters-300x172.png 300w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/cumdisasters-1024x586.png 1024w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/cumdisasters-1536x879.png 1536w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/cumdisasters.png 1550w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-8f0fbd7 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"8f0fbd7\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-ecdab59\" data-id=\"ecdab59\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-1be0773 elementor-widget elementor-widget-spacer\" data-id=\"1be0773\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-5842656 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"5842656\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-41b7f0b\" data-id=\"41b7f0b\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-3b920eb elementor-widget elementor-widget-text-editor\" data-id=\"3b920eb\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-family: Poppins;font-size: 13px;font-style: normal;font-weight: 400\">We refer to a changepoint as the moment in time when the rate of an event occurring changes. In the context of this project, if we assume \ud835\udc5b changepoints exist, then we denote \ud835\udc47\ud835\udc58 as the date of the \ud835\udc58\ud835\udc61\u210e changepoint (for \ud835\udc58 = 1, 2, \u2026 , \ud835\udc5b). To simplify our calculations, time was recorded as a discrete variable, thus, although this is not exact, we have assumed a changepoint can only be located directly after the beginning of a year. Additionally, we presume the rate does not change in the first year and doing so limits \ud835\udc47\ud835\udc58 to all integer values between 1852 and 1962. Therefore, when \ud835\udc5b changepoints exist, the time series of the mining disasters is split into \ud835\udc5b + 1 segments.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-567db85 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"567db85\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-c9fd59b\" data-id=\"c9fd59b\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-ccb98fb elementor-widget elementor-widget-heading\" data-id=\"ccb98fb\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">2.2 Identifying Most Likely Locations of Changepoints<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-cdb135b elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"cdb135b\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-7416d98\" data-id=\"7416d98\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-ba9f0cb elementor-widget elementor-widget-text-editor\" data-id=\"ba9f0cb\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-family: Poppins;font-size: 13px;font-style: normal;font-weight: 400\">The first aim of this project was to identify where the changepoints are likely to have happen. This was done by calculating the corresponding marginal (conditional) posterior distribution. Figure 2 shows the marginal (conditional) posterior distribution of changepoints \ud835\udc471, \ud835\udc472, \ud835\udc473, obtained when using a three changepoint model.\u00a0 To detect where these changepoints are likely to have happened, 20,000 samples were taken from each marginal (conditional) posterior distribution.\u00a0The mode of each 20,000 samples was taken to be the most likely location for the corresponding changepoint.\u00a0The modes of \ud835\udc471, \ud835\udc472, \ud835\udc473, indicated that these are most likely located in 1892, 1930, 1948, respectively.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-7b94db8 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"7b94db8\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-547f6d9\" data-id=\"547f6d9\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-57b9c0a elementor-widget elementor-widget-image\" data-id=\"57b9c0a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"768\" height=\"558\" src=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-posterior-distribution-768x558.png\" class=\"attachment-medium_large size-medium_large wp-image-959\" alt=\"Marginal posterior distribution\" srcset=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-posterior-distribution-768x558.png 768w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-posterior-distribution-300x218.png 300w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-posterior-distribution-1024x745.png 1024w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-posterior-distribution.png 1191w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-78dc0db elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"78dc0db\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-4960ac2\" data-id=\"4960ac2\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-0932fc4 elementor-widget elementor-widget-spacer\" data-id=\"0932fc4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-f4105db elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"f4105db\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-773ffe9\" data-id=\"773ffe9\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-9156d66 elementor-widget elementor-widget-heading\" data-id=\"9156d66\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">2.3 Identifying Coal Mining Disaster Rates<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-f72ea52 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"f72ea52\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-b58c5d6\" data-id=\"b58c5d6\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-1a7c3f5 elementor-widget elementor-widget-text-editor\" data-id=\"1a7c3f5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-family: Poppins;font-size: 13px;font-style: normal;font-weight: 400\">Using the samples of changepoint locations, it is now possible to sample the corresponding mining disaster rates. The mining disaster rates were sampled from their corresponding conditional posterior distribution. When choosing a model with \ud835\udc5b changepoints, 20,000 samples were produced for each of the \ud835\udc5b + 1 corresponding mining disaster rates. Figure 3 shows the conditional posterior distributions of \ud835\udf061, \ud835\udf062, \ud835\udf063 and \ud835\udf064. This helps us identify the rate of yearly mining disasters for each segment.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-906e9fc elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"906e9fc\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-f22f397\" data-id=\"f22f397\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-debf6d0 elementor-widget elementor-widget-image\" data-id=\"debf6d0\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"768\" height=\"520\" src=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/conditional-posterior-distribution-rate-768x520.png\" class=\"attachment-medium_large size-medium_large wp-image-964\" alt=\"Conditional posterior distribution rate\" srcset=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/conditional-posterior-distribution-rate-768x520.png 768w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/conditional-posterior-distribution-rate-300x203.png 300w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/conditional-posterior-distribution-rate-1024x694.png 1024w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/conditional-posterior-distribution-rate.png 1297w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-080efd4 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"080efd4\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-58a6761\" data-id=\"58a6761\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-26be6a5 elementor-widget elementor-widget-spacer\" data-id=\"26be6a5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-9b7b211 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"9b7b211\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-9981c92\" data-id=\"9981c92\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-2063f40 elementor-widget elementor-widget-heading\" data-id=\"2063f40\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">2.4  Predictions of the Cumulative Number of Coal Mining Disasters<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-f603ca9 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"f603ca9\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-6aa2fff\" data-id=\"6aa2fff\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-68afc14 elementor-widget elementor-widget-text-editor\" data-id=\"68afc14\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p style=\"font-family: Poppins;font-size: 13px;font-style: normal;font-weight: 400\">Using the data from the samples, we are now interested in producing predictions of the cumulative number of mining disasters. This was done using the 20,000 sampled location for each \ud835\udc5b changepoints and 20,000 samples of each corresponding \ud835\udc5b + 1 mining disaster rates. The median and 95% prediction interval of cumulative number of mining disasters for each year were computed.\u00a0These give us the posterior predictive distributions of cumulative number of coal mining disaster; these are plotted in Figure 4.\u00a0<\/p><p style=\"font-family: Poppins;font-size: 13px;font-style: normal;font-weight: 400\">These plots give us an idea of how well the models with different number of changepoints explain the data observed. From the models compared in Figure 4, three changepoints seems to best explain the data. However, this is expected, as the more changepoints we add, the more flexibility the models have to explain the data observed. However, to determine which model<br \/>best explains the data we will penalise the models\u2019 complexity.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-7eed7a4 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"7eed7a4\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-45abb6a\" data-id=\"45abb6a\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-a9c83d2 elementor-widget elementor-widget-image\" data-id=\"a9c83d2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"540\" src=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/prediction-intervals-768x540.png\" class=\"attachment-medium_large size-medium_large wp-image-965\" alt=\"Prediction intervals\" srcset=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/prediction-intervals-768x540.png 768w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/prediction-intervals-300x211.png 300w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/prediction-intervals-1024x720.png 1024w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/prediction-intervals.png 1288w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-b9ad638 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"b9ad638\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-e5f5758\" data-id=\"e5f5758\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-4d85ec2 elementor-widget elementor-widget-spacer\" data-id=\"4d85ec2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-338064a elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"338064a\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-286bea3\" data-id=\"286bea3\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-9aa984f elementor-widget elementor-widget-heading\" data-id=\"9aa984f\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">2.5 Model Selection<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-b1f2a41 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"b1f2a41\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-8bf4808\" data-id=\"8bf4808\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-8867ee2 elementor-widget elementor-widget-text-editor\" data-id=\"8867ee2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-size: 13px\">The third and final aim of this project was to compare models with different number of changepoints using marginal likelihood evaluation procedures. Occam\u2019s razor tells us to favour the simpler models over more complex ones. Furthermore, Occam\u2019s razor is a consequence of Bayesian inference <a href=\"https:\/\/www.jstor.org\/stable\/29774559?casa_token=i71LApgF6ZsAAAAA%3AjhxWKoN55TllPGbvwDiOcA1k13qQ6CJdVUw1n-oEOPdKGLsU7puDKSlHZ3-2z3jEsmv570oXha0cyRmqIEg6gEp1_zomRcHzEsH6PVb_zQPzFxzFgA&amp;seq=1#metadata_info_tab_contents\" target=\"_blank\" rel=\"noopener\">(Jefferys &amp; Berger, 1992)<\/a>. In the context of this project, it means that as more complex models (more changepoints) tend to be more flexible, that flexibility is automatically penalised by Bayesian inference. The marginal likelihood of a model with different number of changepoints were evaluated using equation 9; Figure 5 shows the results.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-fa25fbe elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"fa25fbe\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-3ed8ec9\" data-id=\"3ed8ec9\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-69cb4c7 elementor-widget elementor-widget-image\" data-id=\"69cb4c7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"336\" src=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-likelihoods-768x336.png\" class=\"attachment-medium_large size-medium_large wp-image-966\" alt=\"Marginal likelihoods\" srcset=\"https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-likelihoods-768x336.png 768w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-likelihoods-300x131.png 300w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-likelihoods-1024x448.png 1024w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-likelihoods-1536x671.png 1536w, https:\/\/www.lancaster.ac.uk\/stor-i-student-sites\/thomas-newman\/wp-content\/uploads\/sites\/37\/2022\/02\/marginal-likelihoods.png 1874w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-2353ec9 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"2353ec9\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-9d896df\" data-id=\"9d896df\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-6f92d71 elementor-widget elementor-widget-spacer\" data-id=\"6f92d71\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-12097c2 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"12097c2\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-e21acf3\" data-id=\"e21acf3\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-1908baa elementor-widget elementor-widget-text-editor\" data-id=\"1908baa\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-family: Poppins;font-size: 13px;font-style: normal;font-weight: 400\">For more than seven changepoints, the models\u2019 complexity meant that the marginal likelihoods could not be computed due to a lack of computer memory. However, the marginal likelihoods are expected to monotonically decrease, because the penalisation due to the addition of an extra changepoint outweighs the increase in how well the model explains the data. From Figure 5, we can see that four or five changepoints are most likely to best describe the observed data. The marginal likelihood of the model with four changepoints is very slightly greater, therefore, it can be considered as the best model to describe the data. When using a four changepoint model, the locations of changepoints are likely to be 1892, 1897, 1930 and 1948 for \ud835\udc471, \ud835\udc472, \ud835\udc473 and \ud835\udc474, respectively.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-3596bc7 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"3596bc7\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-e11d213\" data-id=\"e11d213\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-45bace7 elementor-widget elementor-widget-heading\" data-id=\"45bace7\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">3. Conclusion<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-e13b6cd elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"e13b6cd\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-e95084f\" data-id=\"e95084f\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-591c5dc elementor-widget elementor-widget-text-editor\" data-id=\"591c5dc\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-family: Poppins;font-size: 13px;font-style: normal;font-weight: 400\">The aim of this project was to detect changes in the rate of yearly coal mining disasters in the UK between 1851 and 1962 using a Bayesian approach. Additionally, the goal was to determine the model which best explains the data observed. Direct sampling was chosen as the inference method implemented to fit models with different number of changepoints. The first step was to identify the most likely location for each changepoint by sampling from their\u00a0 respective marginal (conditional) posterior distribution. Then, their corresponding mining disaster rates were sampled from their conditional posterior distributions. With samples of both changepoint locations and mining disaster rates, samples of predicted yearly number of coal mining disasters were produced. These were then cumulatively summed before obtaining the corresponding posterior predictive distribution. To determine the model which best describes the observed data, marginal likelihood evaluation procedures were implemented. Because we used Bayesian inference, the models\u2019 complexity was automatically penalised. Thus, we do not have to worry about models explaining the data well simply because they have many changepoints. Comparing the models revealed that a four changepoint model is most suitable to explain the data. These changepoints are most likely to be in 1892, 1897, 1930 and 1948 for \ud835\udc471, \ud835\udc472, \ud835\udc473 and \ud835\udc474, respectively<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Around the world, mining disasters are the source of thousands of deaths every year. Amongst the different types of mining methods, underground coal mining is particularly dangerous&#8230;.<\/p>\n","protected":false},"author":40,"featured_media":1022,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"ocean_post_layout":"full-width","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"0","ocean_second_sidebar":"0","ocean_disable_margins":"enable","ocean_add_body_class":"","ocean_shortcode_before_top_bar":"","ocean_shortcode_after_top_bar":"","ocean_shortcode_before_header":"","ocean_shortcode_after_header":"","ocean_has_shortcode":"","ocean_shortcode_after_title":"","ocean_shortcode_before_footer_widgets":"","ocean_shortcode_after_footer_widgets":"","ocean_shortcode_before_footer_bottom":"","ocean_shortcode_after_footer_bottom":"","ocean_display_top_bar":"default","ocean_display_header":"default","ocean_header_style":"","ocean_center_header_left_menu":"0","ocean_custom_header_template":"0","ocean_custom_logo":0,"ocean_custom_retina_logo":0,"ocean_custom_logo_max_width":0,"ocean_custom_logo_tablet_max_width":0,"ocean_custom_logo_mobile_max_width":0,"ocean_custom_logo_max_height":0,"ocean_custom_logo_tablet_max_height":0,"ocean_custom_logo_mobile_max_height":0,"ocean_header_custom_menu":"0","ocean_menu_typo_font_family":"0","ocean_menu_typo_font_subset":"","ocean_menu_typo_font_size":0,"ocean_menu_typo_font_size_tablet":0,"ocean_menu_typo_font_size_mobile":0,"ocean_menu_typo_font_size_unit":"px","ocean_menu_typo_font_weight":"","ocean_menu_typo_font_weight_tablet":"","ocean_menu_typo_font_weight_mobile":"","ocean_menu_typo_transform":"","ocean_menu_typo_transform_tablet":"","ocean_menu_typo_transform_mobile":"","ocean_menu_typo_line_height":0,"ocean_menu_typo_line_height_tablet":0,"ocean_menu_typo_line_height_mobile":0,"ocean_menu_typo_line_height_unit":"","ocean_menu_typo_spacing":0,"ocean_menu_typo_spacing_tablet":0,"ocean_menu_typo_spacing_mobile":0,"ocean_menu_typo_spacing_unit":"","ocean_menu_link_color":"","ocean_menu_link_color_hover":"","ocean_menu_link_color_active":"","ocean_menu_link_background":"","ocean_menu_link_hover_background":"","ocean_menu_link_active_background":"","ocean_menu_social_links_bg":"","ocean_menu_social_hover_links_bg":"","ocean_menu_social_links_color":"","ocean_menu_social_hover_links_color":"","ocean_disable_title":"default","ocean_disable_heading":"default","ocean_post_title":"","ocean_post_subheading":"","ocean_post_title_style":"","ocean_post_title_background_color":"","ocean_post_title_background":0,"ocean_post_title_bg_image_position":"","ocean_post_title_bg_image_attachment":"","ocean_post_title_bg_image_repeat":"","ocean_post_title_bg_image_size":"","ocean_post_title_height":0,"ocean_post_title_bg_overlay":0.5,"ocean_post_title_bg_overlay_color":"","ocean_disable_breadcrumbs":"default","ocean_breadcrumbs_color":"","ocean_breadcrumbs_separator_color":"","ocean_breadcrumbs_links_color":"","ocean_breadcrumbs_links_hover_color":"","ocean_display_footer_widgets":"default","ocean_display_footer_bottom":"default","ocean_custom_footer_template":"0","slim_seo":{"description":".","title":"Yearly Coal Mining Disasters - 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