{"id":145,"date":"2005-12-04T22:16:45","date_gmt":"2005-12-05T04:16:45","guid":{"rendered":"http:\/\/hunch.net\/?p=145"},"modified":"2005-12-04T22:23:45","modified_gmt":"2005-12-05T04:23:45","slug":"watchword-model","status":"publish","type":"post","link":"https:\/\/hunch.net\/?p=145","title":{"rendered":"Watchword: model"},"content":{"rendered":"<p>In everyday use a model is a system which explains the behavior of some system, hopefully at the level where some alteration of the model predicts some alteration of the real-world system.   In machine learning &#8220;model&#8221; has several variant definitions.<\/p>\n<ol>\n<li><strong>Everyday<\/strong>.  The common definition is sometimes used.<\/li>\n<li><strong>Parameterized<\/strong>. Sometimes model is a short-hand for &#8220;parameterized model&#8221;.  Here, it refers to a model with unspecified free parameters.  In the Bayesian learning approach, you typically have a prior over (everyday) models.<\/li>\n<li><strong>Predictive<\/strong>.  Even further from everyday use is the predictive model.  Examples of this are &#8220;my model is a decision tree&#8221; or &#8220;my model is a support vector machine&#8221;.  Here, there is no real sense in which an SVM explains the underlying process.  For example, an SVM tells us nothing in particular about how alterations to the real-world system would create a change.<\/li>\n<\/ol>\n<p>Which definition is being used at any particular time is important information.  For example, if it&#8217;s a parameterized or predictive model, this implies some learning is required.  If it&#8217;s a predictive model, then the set of operations which can be done to the model are restricted with respect to everyday usage.  I don&#8217;t have any particular advice here other than &#8220;watch out&#8221;&#8212;be aware of the distinctions, watch for this source of ambiguity, and clarify when necessary.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In everyday use a model is a system which explains the behavior of some system, hopefully at the level where some alteration of the model predicts some alteration of the real-world system. In machine learning &#8220;model&#8221; has several variant definitions. Everyday. The common definition is sometimes used. Parameterized. Sometimes model is a short-hand for &#8220;parameterized &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/hunch.net\/?p=145\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Watchword: model&#8221;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,15],"tags":[],"class_list":["post-145","post","type-post","status-publish","format-standard","hentry","category-bayesian","category-definitions"],"_links":{"self":[{"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/posts\/145","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/hunch.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=145"}],"version-history":[{"count":0,"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/posts\/145\/revisions"}],"wp:attachment":[{"href":"https:\/\/hunch.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=145"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hunch.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=145"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hunch.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=145"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}