{"id":185,"date":"2005-04-08T02:42:07","date_gmt":"2005-04-08T02:42:07","guid":{"rendered":"http:\/\/vafs.dungnq.local\/2005\/04\/08\/phan-bo-weibull-trong-nghien-cuu-cau-truc-rung-va-phuong-phap-uoc-luong-tham-so\/"},"modified":"2013-10-06T08:59:26","modified_gmt":"2013-10-06T01:59:26","slug":"phan-bo-weibull-trong-nghien-cuu-cau-truc-rung-va-phuong-phap-uoc-luong-tham-so","status":"publish","type":"post","link":"https:\/\/vafs.gov.vn\/vn\/phan-bo-weibull-trong-nghien-cuu-cau-truc-rung-va-phuong-phap-uoc-luong-tham-so\/","title":{"rendered":"PH\u00c2N B\u1ed0 WEIBULL TRONG NGHI\u00caN C\u1ee8U C\u1ea4U TR\u00daC R\u1eeaNG V\u00c0 PH\u01af\u01a0NG PH\u00c1P \u01af\u1edaC L\u01af\u1ee2NG THAM S\u1ed0"},"content":{"rendered":"

H\u00e0m Weibull c\u00f3 \u00fd ngh\u0129a quan tr\u1ecdng trong vi\u1ec7c bi\u1ec3u di\u1ec5n ph\u00e2n b\u1ed1 tu\u1ed5i \u0111\u1eddi c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng s\u1ed1ng. N\u00f3 \u0111\u00e3 v\u00e0 \u0111ang \u0111\u01b0\u1ee3c c\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u l\u00e2m nghi\u1ec7p s\u1eed d\u1ee5ng m\u1ed9t c\u00e1ch ph\u1ed5 bi\u1ebfn trong nghi\u00ean c\u1ee9u c\u1ea5u tr\u00fac r\u1eebng, \u0111\u1eb7c bi\u1ec7t l\u00e0 \u0111\u1ec3 nghi\u00ean c\u1ee9u ph\u00e2n b\u1ed1 s\u1ed1 c\u00e2y theo \u0111\u01b0\u1eddng k\u00ednh. Trong b\u00e0i n\u00e0y ch\u00fang t\u00f4i xin gi\u1edbi thi\u1ec7u m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p \u01b0\u1edbc l\u01b0\u1ee3ng c\u00e1c tham s\u1ed1 c\u1ee7a h\u00e0m Weibull v\u00e0 v\u00ed d\u1ee5 \u1ee9ng d\u1ee5ng c\u1ee7a h\u00e0m trong nghi\u00ean c\u1ee9u c\u1ea5u tr\u00fac r\u1eebng. <\/p>\n

1. \u0110\u1ecbnh ngh\u0129a (Mueler\/Neumann\/Storm, 1973)<\/b> <\/p>\n

M\u1ed9t bi\u1ebfn ng\u1eabu nhi\u00ean li\u00ean t\u1ee5c X c\u00f3 ph\u00e2n b\u1ed1 Weibull v\u1edbi c\u00e1c tham s\u1ed1 a, bv\u00e0 xo<\/sub> ( a>0, b>0, xo <\/sub>=”s\u1ed1” th\u1ef1c b\u1ea5t k\u1ef3) khi h\u00e0m ph\u00e2n b\u1ed1 Fx<\/sub> (x) c\u00f3 d\u1ea1ng: <\/p>\n

1- exp {- [( x- xo<\/sub> )\/b] a<\/sup>} v\u1edbi x> xo<\/sub><\/p>\n

Fx<\/sub> (x) = <\/p>\n

0 v\u1edbi x\u00a3xo<\/sub><\/p>\n

v\u00e0 h\u00e0m m\u1eadt \u0111\u1ed9 fx<\/sub> (x) c\u00f3 d\u1ea1ng: <\/p>\n

<\/p>\n

a\/b[( x- xo<\/sub> )\/b] a<\/sup>-1<\/sup> exp {- [( x- xo<\/sub> )\/b] a<\/sup>} v\u1edbi x> xo<\/sub><\/p>\n

fx<\/sub> (x) = <\/p>\n

0 v\u1edbi x\u00a3xo<\/sub><\/p>\n

\u0110\u1ed1i v\u1edbi h\u00e0m Weibull ta c\u00f3: <\/p>\n

E<\/b>X = xo <\/sub>+ bG(1\/a+ 1), <\/p>\n

D<\/b>2<\/sup>X = b2<\/sup>[ G(2\/a+1) – G2<\/sup>(1\/a+1)] <\/p>\n

Ph\u00e2n b\u1ed1 Weibull c\u00f3 vai tr\u00f2 r\u1ea5t quan trong trong bi\u1ec5u di\u1ec5n tu\u1ed5i \u0111\u1eddi c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng s\u1ed1ng, \u0111\u00f3 l\u00e0 c\u00e1c h\u1ec7 \u0111\u01b0\u1ee3c c\u1ea5u th\u00e0nh th\u00f4ng qua c\u00e1c ph\u1ea7n t\u1eed k\u1ebf ti\u1ebfp nhau \u0111\u1eb7c tr\u01b0ng b\u1edfi tu\u1ed5i \u0111\u1eddi c\u1ee7a c\u00e1c th\u00e0nh vi\u00ean y\u1ebfu nh\u1ea5t trong chu\u1ed5i c\u00e1c ph\u1ea7n t\u1eed. Gi\u1ea3 s\u1eed ta c\u00f3 z1<\/sub>, z2<\/sub>, \u2026, zn<\/sub> l\u00e0 c\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng ng\u1eabu nhi\u00ean \u0111\u1ed9c l\u1eadp, t\u01b0\u01a1ng t\u1ef1 tu\u00e2n theo m\u1ed9t h\u00e0m ph\u00e2n b\u1ed1 F (b\u1ea5t k\u1ef3). G\u1ecdi an<\/sub> + xo<\/sub> l\u00e0 tr\u1ecb s\u1ed1 c\u1ee7a F v\u1edbi b\u1eadc 1\/n th\u00ec \u0111\u1ea1i l\u01b0\u1ee3ng ng\u1eabu nhi\u00ean <\/p>\n

1\/an<\/sub> min (z1<\/sub>, z2<\/sub>, \u2026, zn<\/sub> ) <\/p>\n

ti\u1ec7m c\u1eadn (\u0111\u1ed1i v\u1edbi n\u00e0\u00a5) ph\u00e2n b\u1ed1 Weibull v\u1edbi c\u00e1c tham s\u1ed1 a, 1 v\u00e0 xo <\/sub>trong tr\u01b0\u1eddng h\u1ee3p F tho\u1ea3 m\u00e3n c\u00e1c \u0111i\u1ec1u ki\u1ec7n sau: <\/p>\n

1. F(xo<\/sub>) = 0 v\u00e0 F(xo<\/sub> + e) >0 v\u1edbi t\u1ea5t c\u1ea3 e>0, <\/p>\n

2. lim [F(kx+xo<\/sub>)\/F(x+xo<\/sub>)] = k2<\/sup> v\u1edbi t\u1ea5t c\u1ea3 k>0 <\/p>\n

x\u00af0 <\/p>\n

\u0110i\u1ec1u ki\u1ec7n 2 \u0111\u1eb7c tr\u01b0ng cho ph\u1ea3n \u1ee9ng t\u0103ng tr\u01b0\u1edfng c\u1ee7a F v\u1ec1 ph\u00eda ph\u1ea3i c\u1ee7a xo<\/sub> . <\/p>\n

N\u1ebfu X tu\u00e2n theo ph\u00e2n b\u1ed1 Weibull v\u1edbi c\u00e1c tham s\u1ed1 a, bv\u00e0 xo<\/sub> th\u00ec Y=”(X-xo<\/sub>)\/bc\u0169ng tu\u00e2n theo ph\u00e2n b\u1ed1 Weibull v\u00e0 v\u1edbi c\u00e1c tham s\u1ed1 l\u00e0 a, 1 v\u00e0 0. Do \u0111\u00f3 ng\u01b0\u1eddi ta c\u00f3 th\u1ec3 r\u00fat g\u1ecdn ph\u00e2n b\u1ed1 Weibull trong pham vi Y. G\u1eefa c\u00e1c h\u00e0m ph\u00e2n b\u1ed1 Fx c\u0169ng nh\u01b0 Fy v\u00e0 tr\u1ecb s\u1ed1 wq;<\/sub>a<\/sub>,<\/sub>b<\/sub>,xo<\/sub>c\u0169ng nh\u01b0 wq;<\/sub>a<\/sub>,1,0 <\/sub>= wq;<\/sub>a<\/sub>c\u1ee7a ph\u00e2n b\u1ed1 Weibull chung v\u00e0 ph\u00e2n b\u1ed1 Weibull r\u00fat g\u1ecdn c\u00f3 c\u00e1c quan h\u1ec7: <\/p>\n

Fx<\/sub>(x) = Fy<\/sub>[(x-xo<\/sub>)\/b] <\/p>\n

wq;<\/sub>a<\/sub>,<\/sub>b<\/sub>,xo<\/sub>= xo<\/sub> + bwq;<\/sub>a<\/sub>. <\/p>\n

Gi\u00e1 tr\u1ecb \u0111\u1eb7c bi\u1ec7t c\u1ee7a c\u00e1c tham s\u1ed1:<\/i> <\/p>\n

1. N\u1ebfu a= 1 v\u00e0 xo<\/sub> = 0 th\u00ec ph\u00e2n b\u1ed1 tr\u1edf v\u1ec1 ph\u00e2n b\u1ed1 m\u0169 v\u1edbi h\u00e0m m\u1eadt \u0111\u1ed9 l\u00e0: <\/p>\n

1\/bexp(-(x\/b)) v\u1edbi x> 0 <\/p>\n

fx<\/sub> (x) = <\/p>\n

0 v\u1edbi x\u00a30 <\/p>\n

Ta c\u00f3 E<\/b>X = b. <\/p>\n

2. N\u1ebfu a= 2 v\u00e0 xo<\/sub> = 0 th\u00ec ph\u00e2n b\u1ed1 tr\u1edf v\u1ec1 ph\u00e2n b\u1ed1 RAYLEICH v\u1edbi h\u00e0m m\u1eadt \u0111\u1ed9 l\u00e0: <\/p>\n

2x\/b2<\/sup>exp(-(x\/b)2<\/sup>) v\u1edbi x> 0 <\/p>\n

fx<\/sub> (x) = <\/p>\n

0 v\u1edbi x\u00a30 <\/p>\n

Ta c\u00f3: E<\/b>X = (b\/2)\u00d6p.N\u1ebfu a<3,60232 th\u00ec ph\u00e2n b\u1ed1 l\u1ec7ch tr\u00e1i; N\u1ebfu a>3,60232 th\u00ec ph\u00e2n b\u1ed1 l\u1ec7ch ph\u1ea3i v\u00e0 khi a=”3,60232″ th\u00ec ph\u00e2n b\u1ed1 \u0111\u1ec1u.<\/p>\n","protected":false},"excerpt":{"rendered":"

H\u00e0m Weibull c\u00f3 \u00fd ngh\u0129a quan tr\u1ecdng trong vi\u1ec7c bi\u1ec3u di\u1ec5n ph\u00e2n b\u1ed1 tu\u1ed5i \u0111\u1eddi c\u1ee7a c\u00e1c h\u1ec7 th\u1ed1ng s\u1ed1ng. N\u00f3 \u0111\u00e3 v\u00e0 \u0111ang \u0111\u01b0\u1ee3c c\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u l\u00e2m nghi\u1ec7p s\u1eed d\u1ee5ng m\u1ed9t c\u00e1ch ph\u1ed5 bi\u1ebfn trong nghi\u00ean c\u1ee9u c\u1ea5u tr\u00fac r\u1eebng, \u0111\u1eb7c bi\u1ec7t l\u00e0 \u0111\u1ec3 nghi\u00ean c\u1ee9u ph\u00e2n b\u1ed1 s\u1ed1 c\u00e2y theo \u0111\u01b0\u1eddng k\u00ednh. Trong b\u00e0i n\u00e0y ch\u00fang t\u00f4i xin gi\u1edbi thi\u1ec7u m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p \u01b0\u1edbc l\u01b0\u1ee3ng c\u00e1c tham s\u1ed1 c\u1ee7a h\u00e0m Weibull v\u00e0 v\u00ed d\u1ee5 \u1ee9ng d\u1ee5ng c\u1ee7a h\u00e0m trong nghi\u00ean c\u1ee9u c\u1ea5u tr\u00fac r\u1eebng.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[21],"tags":[],"_links":{"self":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/185"}],"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\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/comments?post=185"}],"version-history":[{"count":3,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/185\/revisions"}],"predecessor-version":[{"id":8442,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/185\/revisions\/8442"}],"wp:attachment":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/media?parent=185"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/categories?post=185"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/tags?post=185"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}