{"id":9688,"date":"2011-12-09T04:13:57","date_gmt":"2011-12-08T21:13:57","guid":{"rendered":"http:\/\/vafs.gov.vn\/vn\/2011\/12\/phuong-phap-uoc-luong-tham-so-cua-ham-schumacher\/"},"modified":"2015-05-19T14:17:15","modified_gmt":"2015-05-19T07:17:15","slug":"phuong-phap-uoc-luong-tham-so-cua-ham-schumacher","status":"publish","type":"post","link":"https:\/\/vafs.gov.vn\/vn\/phuong-phap-uoc-luong-tham-so-cua-ham-schumacher\/","title":{"rendered":"Ph\u01b0\u01a1ng ph\u00e1p \u01b0\u1edbc l\u01b0\u1ee3ng tham s\u1ed1 c\u1ee7a h\u00e0m Schumacher"},"content":{"rendered":"<p><strong>Nguy\u1ec5n V\u0103n Th\u00eam<\/strong><\/p>\n<p><em>Tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc N\u00f4ng L\u00e2m Tp. H\u1ed3 Ch\u00ed Minh<\/em><\/p>\n<p><strong>T\u00d3M T\u1eaeT<\/strong><\/p>\n<p>B\u00e0i b\u00e1o n\u00e0y gi\u1edbi thi\u1ec7u s\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 k\u1ebft qu\u1ea3 ph\u00e2n t\u00edch v\u00e0 d\u1ef1 \u0111o\u00e1n qu\u00e1 tr\u00ecnh sinh tr\u01b0\u1edfng c\u1ee7a c\u00e2y c\u00e1 th\u1ec3 b\u1eb1ng h\u00e0m Schumacher do \u1ea3nh h\u01b0\u1edfng c\u1ee7a ph\u01b0\u01a1ng ph\u00e1p \u01b0\u1edbc l\u01b0\u1ee3ng ba tham s\u1ed1 v\u00e0 vi\u1ec7c ch\u1ecdn l\u1ef1a ti\u00eau chu\u1ea9n d\u1eebng hay ti\u00eau chu\u1ea9n \u0111\u00e1nh gi\u00e1 m\u1ee9c \u0111\u1ed9 ph\u00f9 h\u1ee3p c\u1ee7a m\u00f4 h\u00ecnh. \u0110\u1ec3 l\u00e0m r\u00f5 v\u1ea5n \u0111\u1ec1 \u0111\u1eb7t ra tr\u00ean \u0111\u00e2y, t\u00e1c gi\u1ea3 \u0111\u00e3 l\u00e0m ph\u00f9 h\u1ee3p s\u1ed1 li\u1ec7u th\u1ec3 t\u00edch th\u00e2n c\u00e2y Th\u00f4ng ba l\u00e1 <em>(Pinus keysia<\/em> Royle ex Gordon<em>)<\/em> 60 tu\u1ed5i v\u1edbi h\u00e0m Schumacher; trong \u0111\u00f3 c\u00e1c tham s\u1ed1 c\u1ee7a h\u00e0m n\u00e0y \u0111\u01b0\u1ee3c \u01b0\u1edbc l\u01b0\u1ee3ng theo hai ph\u01b0\u01a1ng ph\u00e1p kh\u00e1c nhau \u2013 \u0111\u00f3 l\u00e0 h\u1ed3i quy tuy\u1ebfn t\u00ednh v\u00e0 h\u1ed3i quy phi tuy\u1ebfn t\u00ednh. \u0110\u1ed1i v\u1edbi m\u1ed7i ph\u01b0\u01a1ng ph\u00e1p, h\u00e0m c\u1ee7a m\u00f4 h\u00ecnh \u01b0\u1edbc l\u01b0\u1ee3ng ph\u00f9 h\u1ee3p nh\u1ea5t \u0111\u01b0\u1ee3c ch\u1ecdn t\u1eeb 5 ti\u00eau chu\u1ea9n sau \u0111\u00e2y: (1) h\u1ec7 s\u1ed1 x\u00e1c \u0111\u1ecbnh l\u1edbn nh\u1ea5t (R<sup>2<\/sup><sub>max<\/sub>); (2) sai s\u1ed1 \u01b0\u1edbc l\u01b0\u1ee3ng nh\u1ecf nh\u1ea5t (SE<sub>min<\/sub>); (3) sai s\u1ed1 tuy\u1ec7t \u0111\u1ed1i trung b\u00ecnh nh\u1ecf nh\u1ea5t (MAE<sub>min<\/sub>); (4) sai s\u1ed1 tuy\u1ec7t \u0111\u1ed1i trung b\u00ecnh t\u00ednh theo ph\u1ea7n tr\u0103m nh\u1ecf nh\u1ea5t (MAPE<sub>min<\/sub>); (5) t\u1ed5ng sai l\u1ec7ch b\u00ecnh ph\u01b0\u01a1ng nh\u1ecf nh\u1ea5t (SSR<sub>min<\/sub>). K\u1ebft qu\u1ea3 nghi\u00ean c\u1ee9u \u0111\u00e3 ch\u1ec9 ra r\u1eb1ng: (1) N\u1ebfu s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p b\u00ecnh ph\u01b0\u01a1ng sai l\u1ec7ch nh\u1ecf nh\u1ea5t \u0111\u1ec3 \u01b0\u1edbc l\u01b0\u1ee3ng c\u00e1c tham s\u1ed1 c\u1ee7a h\u00e0m Schumacher, th\u00ec ph\u01b0\u01a1ng ph\u00e1p c\u1ed1 \u0111\u1ecbnh tham s\u1ed1 m cho ph\u00e9p nh\u1eadn \u0111\u01b0\u1ee3c k\u1ebft qu\u1ea3 ch\u00ednh x\u00e1c h\u01a1n so v\u1edbi ph\u01b0\u01a1ng ph\u00e1p c\u1ed1 \u0111\u1ecbnh tham s\u1ed1 c. (2) C\u00e1c tham s\u1ed1 c\u1ee7a h\u00e0m Schumacher \u0111\u01b0\u1ee3c \u01b0\u1edbc l\u01b0\u1ee3ng theo ph\u01b0\u01a1ng ph\u00e1p h\u1ed3i quy t\u01b0\u01a1ng quan phi tuy\u1ebfn t\u00ednh \u0111\u1ea1t \u0111\u01b0\u1ee3c \u0111\u1ed9 tin c\u1eady cao h\u01a1n so v\u1edbi ph\u01b0\u01a1ng ph\u00e1p b\u00ecnh ph\u01b0\u01a1ng sai l\u1ec7ch nh\u1ecf nh\u1ea5t. (3) N\u1ebfu ch\u1ecdn ph\u01b0\u01a1ng ph\u00e1p \u01b0\u1edbc l\u01b0\u1ee3ng c\u00e1c tham s\u1ed1 c\u1ee7a h\u00e0m Schumacher v\u00e0 ti\u00eau chu\u1ea9n d\u1eebng kh\u00e1c nhau, th\u00ec m\u00f4 h\u00ecnh \u01b0\u1edbc l\u01b0\u1ee3ng ph\u00f9 h\u1ee3p nh\u1ea5t c\u0169ng s\u1ebd kh\u00e1c nhau.<\/p>\n<p><strong>T\u1eeb kh\u00f3a:<\/strong> H\u00e0m Chumacher, \u01b0\u1edbc l\u01b0\u1ee3ng tham s\u1ed1, Ph\u01b0\u01a1ng ph\u00e1p d\u00f2 t\u00ecm, ti\u00eau chu\u1ea9n d\u1eebng, Ph\u01b0\u01a1ng ph\u00e1p b\u00ecnh ph\u01b0\u01a1ng sai l\u1ec7ch nh\u1ecf nh\u1ea5t.<\/p>\n<p><strong>\u0110\u1eb6T V\u1ea4N \u0110\u1ec0<\/strong><\/p>\n<p>Trong l\u00e2m h\u1ecdc v\u00e0 \u0111i\u1ec1u tra r\u1eebng, ng\u01b0\u1eddi ta th\u01b0\u1eddng v\u1eadn d\u1ee5ng nh\u1eefng m\u00f4 h\u00ecnh to\u00e1n \u0111\u1ec3 m\u00f4 t\u1ea3 v\u00e0 ph\u00e2n t\u00edch quy lu\u1eadt bi\u1ebfn \u0111\u1ed5i c\u1ee7a nh\u1eefng nh\u00e2n t\u1ed1 \u0111i\u1ec1u tra (\u0111\u01b0\u1eddng k\u00ednh, chi\u1ec1u cao, th\u1ec3 t\u00edch th\u00e2n c\u00e2y, tr\u1eef l\u01b0\u1ee3ng r\u1eebng\u2026) tr\u00ean c\u00e2y c\u00e1 th\u1ec3 v\u00e0 l\u00e2m ph\u1ea7n. M\u1ed9t trong nh\u1eefng h\u00e0m s\u1ed1 \u0111\u01b0\u1ee3c v\u1eadn d\u1ee5ng nhi\u1ec1u nh\u1ea5t l\u00e0 h\u00e0m Schumacher. H\u00e0m Schumacher c\u00f3 d\u1ea1ng Y = m*exp(-b\/A^c); trong \u0111\u00f3 m, b v\u00e0 c l\u00e0 ba tham s\u1ed1 c\u1ea7n \u01b0\u1edbc l\u01b0\u1ee3ng . Ba tham s\u1ed1 n\u00e0y c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u01b0\u1edbc l\u01b0\u1ee3ng theo hai ph\u01b0\u01a1ng ph\u00e1p kh\u00e1c nhau. Ph\u01b0\u01a1ng ph\u00e1p th\u1ee9 nh\u1ea5t l\u00e0 chuy\u1ec3n h\u00e0m Schumacher v\u1ec1 d\u1ea1ng tuy\u1ebfn t\u00ednh v\u00e0 s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p b\u00ecnh ph\u01b0\u01a1ng sai l\u1ec7ch nh\u1ecf nh\u1ea5t \u0111\u1ec3 \u01b0\u1edbc l\u01b0\u1ee3ng ba tham s\u1ed1 m, b v\u00e0 c. Khi s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p b\u00ecnh ph\u01b0\u01a1ng sai l\u1ec7ch nh\u1ecf nh\u1ea5t, ba tham s\u1ed1 m, b v\u00e0 c c\u1ee7a h\u00e0m Schumacher c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u01b0\u1edbc l\u01b0\u1ee3ng b\u1eb1ng c\u00e1ch c\u1ed1 \u0111\u1ecbnh tham s\u1ed1 c ho\u1eb7c c\u1ed1 \u0111\u1ecbnh tham s\u1ed1 m; sau \u0111\u00f3 \u01b0\u1edbc l\u01b0\u1ee3ng hai tham s\u1ed1 c\u00f2n l\u1ea1i. N\u00f3i chung, gi\u1ea3i ph\u00e1p b\u00ecnh ph\u01b0\u01a1ng nh\u1ecf nh\u1ea5t c\u00f3 \u01b0u \u0111i\u1ec3m l\u00e0 \u01b0\u1edbc l\u01b0\u1ee3ng ph\u01b0\u01a1ng sai kh\u00f4ng tr\u1ec7ch v\u00e0 nh\u1ecf nh\u1ea5t. Ph\u01b0\u01a1ng ph\u00e1p th\u1ee9 hai l\u00e0 x\u00e1c \u0111\u1ecbnh ba tham s\u1ed1 m, b v\u00e0 c c\u1ee7a h\u00e0m Schumacher b\u1eb1ng h\u1ed3i quy phi tuy\u1ebfn t\u00ednh (Nonlinear Regression). Theo \u0111\u00f3, ba tham s\u1ed1 c\u1ee7a h\u00e0m Schumacher \u0111\u01b0\u1ee3c \u01b0\u1edbc l\u01b0\u1ee3ng l\u1eb7p l\u1ea1i nhi\u1ec1u l\u1ea7n cho \u0111\u1ebfn khi \u0111\u1ea1t \u0111\u01b0\u1ee3c t\u1ed5ng b\u00ecnh ph\u01b0\u01a1ng sai l\u1ec7ch kh\u00f4ng \u0111\u1ed5i.<\/p>\n","protected":false},"excerpt":{"rendered":"<p align=\"justify\">\n<span style=\"font-family: Arial; font-size: 10pt\">B&agrave;i b&aacute;o n&agrave;y gi\u1edbi thi\u1ec7u s\u1ef1 kh&aacute;c bi\u1ec7t v\u1ec1 k\u1ebft qu\u1ea3 ph&acirc;n t&iacute;ch v&agrave; d\u1ef1 \u0111o&aacute;n qu&aacute; tr&igrave;nh sinh tr\u01b0\u1edfng c\u1ee7a c&acirc;y c&aacute; th\u1ec3 b\u1eb1ng h&agrave;m Schumacher do \u1ea3nh h\u01b0\u1edfng c\u1ee7a ph\u01b0\u01a1ng ph&aacute;p \u01b0\u1edbc l\u01b0\u1ee3ng ba tham s\u1ed1 v&agrave; vi\u1ec7c ch\u1ecdn l\u1ef1a ti&ecirc;u chu\u1ea9n d\u1eebng hay ti&ecirc;u chu\u1ea9n \u0111&aacute;nh gi&aacute; m\u1ee9c \u0111\u1ed9 ph&ugrave; h\u1ee3p c\u1ee7a m&ocirc; h&igrave;nh. \u0110\u1ec3 l&agrave;m r&otilde; v\u1ea5n \u0111\u1ec1 \u0111\u1eb7t ra tr&ecirc;n \u0111&acirc;y, t&aacute;c gi\u1ea3 \u0111&atilde; l&agrave;m ph&ugrave; h\u1ee3p s\u1ed1 li\u1ec7u th\u1ec3 t&iacute;ch th&acirc;n c&acirc;y Th&ocirc;ng ba l&aacute; <em>(Pinus keysia<\/em> Royle ex Gordon<em>)<\/em> 60 tu\u1ed5i v\u1edbi h&agrave;m Schumacher; trong \u0111&oacute; c&aacute;c tham s\u1ed1 c\u1ee7a h&agrave;m n&agrave;y \u0111\u01b0\u1ee3c \u01b0\u1edbc l\u01b0\u1ee3ng theo hai ph\u01b0\u01a1ng ph&aacute;p kh&aacute;c nhau &ndash; \u0111&oacute; l&agrave; h\u1ed3i quy tuy\u1ebfn t&iacute;nh v&agrave; h\u1ed3i quy phi tuy\u1ebfn t&iacute;nh.<\/span><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[],"_links":{"self":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/9688"}],"collection":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/comments?post=9688"}],"version-history":[{"count":2,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/9688\/revisions"}],"predecessor-version":[{"id":15242,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/9688\/revisions\/15242"}],"wp:attachment":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/media?parent=9688"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/categories?post=9688"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/tags?post=9688"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}