{"id":6551,"date":"2024-05-14T11:09:55","date_gmt":"2024-05-14T09:09:55","guid":{"rendered":"https:\/\/samovar.telecom-sudparis.eu\/?p=6551"},"modified":"2024-05-14T11:09:56","modified_gmt":"2024-05-14T09:09:56","slug":"seminaire-de-lequipe-sop-presente-par-xavier-erny-a-14h-et-elouan-argouarch-a-15h-le-16-05-2024-amphi-c06-a-evry","status":"publish","type":"post","link":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/2024\/05\/14\/seminaire-de-lequipe-sop-presente-par-xavier-erny-a-14h-et-elouan-argouarch-a-15h-le-16-05-2024-amphi-c06-a-evry\/","title":{"rendered":"S\u00e9minaire de l\u2019\u00e9quipe SOP pr\u00e9sent\u00e9 par Xavier Erny \u00e0 14h et Elouan Argouarc\u2019h \u00e0 15h le 16\/05\/2024, amphi C06 \u00e0 Evry"},"content":{"rendered":"\n<p><strong>14h00 <em>Xavier Erny<\/em><\/strong><\/p>\n\n\n\n<p>Titre : \u00c9quations diff\u00e9rentielles stochastiques avec des sauts et mod\u00e8les champ-moyens<br><br>R\u00e9sum\u00e9 : Le but de la pr\u00e9sentation est d&rsquo;introduire la notion de processus ponctuels et d&rsquo;\u00e9quations diff\u00e9rentielles stochastiques \u00e0 sauts, ainsi que leurs utilisations dans les mod\u00e8les. Nous nous int\u00e9resserons principalement \u00e0 des mod\u00e8les de syst\u00e8mes de particules de type champ-moyen (que nous introduirons), et \u00e0 l&rsquo;\u00e9tude de ces syst\u00e8mes quand le nombre de particules tend vers l&rsquo;infini. Pour cela nous utiliserons la notion de g\u00e9n\u00e9rateur infinit\u00e9simal de processus de Markov \u00e0 la fois pour des processus \u00e0 valeurs r\u00e9elles et des processus \u00e0 valeurs mesures. Il n&rsquo;y a pas de pr\u00e9requis pour suivre la pr\u00e9sentation, les concepts principaux seront introduits.<\/p>\n\n\n\n<p><strong>15h00 <em>Elouan Argouarc\u2019h<\/em><\/strong><\/p>\n\n\n\n<p>Titre:&nbsp;Generative vs. discriminative modelling under the lens of uncertainty quantification<\/p>\n\n\n\n<p>Abstract: Learning a parametric model from a given dataset indeed enables to capture intrinsic dependencies between random variables via a parametric conditional probability distribution and in turn predict the value of a label variable given observed variables. In this paper, we undertake a comparative analysis of generative and discriminative approaches which differ in their construction and the structure of the underlying inference problem. Our objective is to compare the ability of both approaches to leverage information from various sources in an epistemic uncertainty aware inference via the posterior predictive distribution. We assess the role of a prior distribution, explicit in the generative case and implicit in the discriminative case, leading to a discussion about discriminative models suffering from imbalance dataset. We then discuss the role of the observed variable which plays a double part in the generative case since the model parameters also indeed depend on this random variable, and we subsequently build upon this argument to discuss the compatibility of both approaches with the problem of semi-supervised learning. We also provide with practical insights and we examine how the modelling choice impacts the sampling from the posterior predictive distribution. With regard to this, we propose a general sampling scheme enabling supervised learning for both approaches, as well as semi-supervised learning when compatible with the considered modelling approach. Throughout this paper, we illustrate our arguments and conclusions using the example of affine regression and validate our comparative analysis through classification simulations using neural network-based models.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>14h00 Xavier Erny Titre : \u00c9quations diff\u00e9rentielles stochastiques avec des sauts et mod\u00e8les champ-moyens R\u00e9sum\u00e9 : Le but de la pr\u00e9sentation est d&rsquo;introduire la notion de processus ponctuels et d&rsquo;\u00e9quations diff\u00e9rentielles stochastiques \u00e0 sauts, ainsi que leurs utilisations dans les mod\u00e8les. Nous nous int\u00e9resserons principalement \u00e0 des mod\u00e8les de syst\u00e8mes de particules de type champ-moyen [&hellip;]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ocean_post_layout":"","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"","ocean_second_sidebar":"","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":"","ocean_custom_header_template":"","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":"","ocean_menu_typo_font_family":"","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":"","ocean_post_oembed":"","ocean_post_self_hosted_media":"","ocean_post_video_embed":"","ocean_link_format":"","ocean_link_format_target":"self","ocean_quote_format":"","ocean_quote_format_link":"post","ocean_gallery_link_images":"on","ocean_gallery_id":[],"footnotes":""},"categories":[286,615],"tags":[],"class_list":["post-6551","post","type-post","status-publish","format-standard","hentry","category-fractualites-ennews-fr","category-seminaire-sop","entry"],"_links":{"self":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/6551","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/comments?post=6551"}],"version-history":[{"count":1,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/6551\/revisions"}],"predecessor-version":[{"id":6552,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/posts\/6551\/revisions\/6552"}],"wp:attachment":[{"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/media?parent=6551"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/categories?post=6551"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/wp-json\/wp\/v2\/tags?post=6551"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}