{"id":18401,"date":"2024-09-10T10:04:36","date_gmt":"2024-09-10T02:04:36","guid":{"rendered":"http:\/\/139.9.1.231\/?p=18401"},"modified":"2024-09-12T20:00:27","modified_gmt":"2024-09-12T12:00:27","slug":"asr-n-gram","status":"publish","type":"post","link":"http:\/\/139.9.1.231\/index.php\/2024\/09\/10\/asr-n-gram\/","title":{"rendered":"ASR\u8bed\u97f3\u8bc6\u522b&#8212;N-gram \u8bed\u8a00\u6a21\u578b"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" width=\"711\" height=\"246\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/08\/image-114.png\" alt=\"\" class=\"wp-image-18402\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/08\/image-114.png 711w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/08\/image-114-300x104.png 300w\" sizes=\"(max-width: 711px) 100vw, 711px\" \/><\/figure>\n\n\n\n<p><strong>\u6700\u8fd1\u5728\u505aASR\u8bed\u97f3\u8bc6\u522b\u4efb\u52a1\uff0c\u57fa\u4e8e\u963f\u91ccFunASR\u6846\u67b6\uff0c\u7279\u6b64\u8bb0\u5f55\u4e0b\u8ddf\u8bed\u8a00\u6a21\u578b\uff08LM\uff09\u76f8\u5173\u77e5\u8bc6\u3002<\/strong><\/p>\n\n\n\n<h3><strong>\u8bed\u8a00\u6a21\u578b\u89e3\u7801<\/strong><\/h3>\n\n\n\n<p>         \u4f20\u7edf\u57fa\u4e8eCD-phone\u58f0\u5b66\u5efa\u6a21ASR\u7cfb\u7edf\u89e3\u7801\u5668\u666e\u904d\u91c7\u7528HCLG\u6784\u5efa\u89e3\u7801\u7f51\u7edc\uff0c\u5f53\u524d\u65b9\u6848\u4e2dparaformer\u58f0\u5b66\u6a21\u578b\u76f4\u63a5\u5bf9\u97f3\u7d20\u6216\u5b57\u7b26\u5efa\u6a21\uff0c\u4e3a\u6b64\u6211\u4eec\u91c7\u7528TLG\uff08Token\u3001Lexicon\u3001Grammar\uff09\u7ed3\u6784\u6784\u5efa\u7edf\u4e00\u89e3\u7801\u7f51\u7edc\uff0c<strong>\u76f4\u63a5\u5c06\u97f3\u7d20\/\u5b57\u7b26\u5e8f\u5217[ paraformer\u58f0\u5b66\u6a21\u578b ]\u3001\u53d1\u97f3\u8bcd\u5178\u3001\u8bed\u8a00\u6a21\u578b\u7f16\u8bd1\u5f62\u6210T\u3001L\u3001G\u4e09\u4e2awfst\u5b50\u7f51\u7edc\uff0c\u518d\u901a\u8fc7composition\u3001determinization\u3001minimization\u7b49\u4e00\u7cfb\u5217\u64cd\u4f5c\u751f\u6210\u7edf\u4e00\u89e3\u7801\u7f51\u7edc\u3002<\/strong><\/p>\n\n\n\n<p>      \u6211\u4eec\u501f\u9274EESEN\u65b9\u6848\uff0c\u57fa\u4e8e<strong>openfst\/kaldi\u6784\u5efaTLG\u89e3\u7801\u7f51\u7edc\u7f16\u8bd1pipeline\uff0c\u652f\u6301\u4ece\u539f\u59cb\u8bed\u6599\u548c\u53d1\u97f3\u8bcd\u5178\u5230\u6700\u7ec8\u89e3\u7801\u8d44\u6e90\u7684\u5168\u6d41\u7a0b\u7f16\u8bd1\uff0c\u4fbf\u4e8e\u7528\u6237\u81ea\u884c\u5b9a\u5236\u9002\u5408\u81ea\u8eab\u7684\u89e3\u7801\u8d44\u6e90\u3002\u5982\u4e0b\u662fTLG\u7f51\u7edc\u7f16\u8bd1\u6d41\u7a0b\u56fe\u3002<\/strong><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-32.png\" alt=\"\" class=\"wp-image-18645\" width=\"378\" height=\"343\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-32.png 676w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-32-300x272.png 300w\" sizes=\"(max-width: 378px) 100vw, 378px\" \/><\/figure><\/div>\n\n\n\n\n\n<h2><strong>\u4e3a\u4ec0\u4e48\u9700\u8981\u8bed\u8a00\u6a21\u578b\uff1f<\/strong><\/h2>\n\n\n\n<p>\u4e3a\u4ec0\u4e48\u6709\u4e9b\u53e5\u5b50\u6bd4\u5176\u4ed6\u53e5\u5b50\u66f4&nbsp;<strong>\u6d41\u7545\uff08fluent\uff09<\/strong>\uff0c\u6216\u8005\u8bf4&nbsp;<strong>\u66f4\u81ea\u7136\uff08natural\uff09<\/strong>\uff1f<br>\u6211\u4eec\u4e3a\u4ec0\u4e48\u5173\u5fc3\u8fd9\u4e2a\u95ee\u9898\u5462\uff1f<br>\u56e0\u4e3a\u5728\u5f88\u591a\u5e94\u7528\u4e2d\uff0c\u6211\u4eec\u5f88\u5173\u5fc3\u8bed\u8a00\u7684\u6d41\u7545\u6027\u4e0e\u81ea\u7136\u6027\u3002<br>\u4f8b\u5982\uff0c\u5728\u8bed\u97f3\u8bc6\u522b\u4e2d\uff0c\u4f60\u542c\u5230\u4e00\u53e5\u8bdd\uff0c\u5e76\u4e14\u60f3\u5c06\u5b83\u8f6c\u6362\u6210\u6587\u672c\uff0c\u6240\u4ee5\u4f60\u9700\u8981\u533a\u5206\u8fd9\u6bb5\u8bed\u97f3\u53ef\u80fd\u5bf9\u5e94\u7684\u4e0d\u540c\u6587\u672c\uff0c\u5e76\u4ece\u4e2d\u9009\u62e9\u66f4\u52a0\u6d41\u7545\u548c\u81ea\u7136\u7684\u7248\u672c\u3002\u6bd4\u5982\u4e0b\u9762\u4e24\u4e2a\u53e5\u5b50\u7684\u53d1\u97f3\u5f88\u63a5\u8fd1\uff1arecognise speech &gt; wreck a nice beach\uff0c\u4ece\u6d41\u7545\u548c\u81ea\u7136\u7684\u89d2\u5ea6\u8003\u8651\uff0c\u663e\u7136\uff0c\u5de6\u8fb9\u7684\u53e5\u5b50\u66f4\u6709\u53ef\u80fd\u4ee3\u8868\u4e86\u8bb2\u8bdd\u8005\u7684\u672c\u610f\u3002\u800c<strong>\u8bed\u8a00\u6a21\u578b\u53ef\u4ee5\u5e2e\u4f60\u505a\u5230\u8fd9\u4e00\u70b9\uff0c\u5b83\u4f1a\u544a\u8bc9\u4f60 \u201crecognise speech\u201d \u662f\u4eba\u4eec\u66f4\u503e\u5411\u8868\u8fbe\u7684\u610f\u601d\u3002<\/strong><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full\"><img loading=\"lazy\" width=\"403\" height=\"37\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/08\/image-116.png\" alt=\"\" class=\"wp-image-18414\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/08\/image-116.png 403w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/08\/image-116-300x28.png 300w\" sizes=\"(max-width: 403px) 100vw, 403px\" \/><\/figure><\/div>\n\n\n\n<ul><li>\u90a3\u4e48\uff0c\u6211\u4eec\u5982\u4f55\u8861\u91cf\u8fd9\u79cd \u201c\u4f18\u5ea6\uff08goodness\uff09\u201d\uff08\u6216\u8005\u8bf4\u6d41\u7545\u5ea6\u3001\u81ea\u7136\u5ea6\uff09\u5462\uff1f<br>\u6211\u4eec\u7528&nbsp;<strong>\u6982\u7387<\/strong>&nbsp;\u6765\u8861\u91cf\u5b83\uff0c\u800c<strong>\u8bed\u8a00\u6a21\u578b\u63d0\u4f9b\u4e86\u4e00\u79cd\u5f88\u81ea\u7136\u7684\u65b9\u5f0f\u6765\u4f30\u8ba1\u53e5\u5b50\u7684\u6982\u7387\u3002<\/strong><\/li><li>\u5728\u6b64\u57fa\u7840\u4e0a\uff0c\u4e00\u65e6\u4f60\u6784\u5efa\u4e86\u4e00\u4e2a\u8bed\u8a00\u6a21\u578b\uff0c\u4f60\u8fd8\u53ef\u4ee5\u7528\u5b83\u6765&nbsp;<strong>\u751f\u6210\uff08generation\uff09<\/strong>&nbsp;\u8bed\u8a00\u3002<\/li><\/ul>\n\n\n\n<h2><strong>\u8bed\u8a00\u6a21\u578b\u53ef\u4ee5\u7528\u4e8e\u54ea\u4e9b\u4efb\u52a1\u5462\uff1f<\/strong><\/h2>\n\n\n\n<ul><li>\u4e3b\u8981\u7528\u4e8e\uff1a<ul><li>\u8bed\u97f3\u8bc6\u522b\uff08Speech recognition\uff09<\/li><li>\u62fc\u5199\u7ea0\u9519\uff08Spelling correction\uff09<\/li><li>\u67e5\u8be2\u8865\u5168\uff08Query completion\uff09<\/li><li>\u5149\u5b66\u5b57\u7b26\u8bc6\u522b\uff08Optical character recognition\uff09<\/li><\/ul><\/li><li>\u5176\u4ed6\u751f\u6210\u4efb\u52a1\uff1a<ul><li>\u673a\u5668\u7ffb\u8bd1\uff08Machine translation\uff09<\/li><li>\u6982\u62ec\uff08Summarisation\uff09<\/li><li>\u5bf9\u8bdd\u7cfb\u7edf\uff08Dialogue systems\uff09<\/li><\/ul><\/li><\/ul>\n\n\n\n<h2>N-gram \u8bed\u8a00\u6a21\u578b<\/h2>\n\n\n\n<p>        N-Gram\u662f\u57fa\u4e8e\u4e00\u4e2a\u5047\u8bbe\uff1a\u7b2cn\u4e2a\u8bcd\u51fa\u73b0\u4e0e\u524dn-1\u4e2a\u8bcd\u76f8\u5173\uff0c\u800c\u4e0e\u5176\u4ed6\u4efb\u4f55\u8bcd\u4e0d\u76f8\u5173\uff08\u8fd9\u4e5f\u662f\u9690\u9a6c\u5c14\u53ef\u592b\u5f53\u4e2d\u7684\u5047\u8bbe\uff09\u3002\u6574\u4e2a\u53e5\u5b50\u51fa\u73b0\u7684\u6982\u7387\u5c31\u7b49\u4e8e\u5404\u4e2a\u8bcd\u51fa\u73b0\u7684\u6982\u7387\u4e58\u79ef\u3002\u5404\u4e2a\u8bcd\u7684\u6982\u7387\u53ef\u4ee5\u901a\u8fc7\u8bed\u6599\u4e2d\u7edf\u8ba1\u8ba1\u7b97\u5f97\u5230\u3002\u901a\u5e38N-Gram\u53d6\u81ea\u6587\u672c\u6216\u8bed\u6599\u5e93\u3002<\/p>\n\n\n\n<h3>\u6982\u7387\uff1a\u4ece\u8054\u5408\u6982\u7387\u5230\u6761\u4ef6\u6982\u7387<\/h3>\n\n\n\n<p>\u6211\u4eec\u7684\u76ee\u6807\u662f\u5f97\u5230\u4e00\u4e2a\u7531&nbsp;m&nbsp;\u4e2a\u5355\u8bcd\u7ec4\u6210\u7684\u4efb\u610f\u5e8f\u5217\uff08\u5373\u4e00\u4e2a\u5305\u542b&nbsp;m&nbsp;\u4e2a\u5355\u8bcd\u7684\u53e5\u5b50\uff09\u7684\u6982\u7387\uff1a<\/p>\n\n\n\n<p class=\"has-text-align-center\"><em>P(w1,w2,\u2026,wm)<\/em><\/p>\n\n\n\n<p>\u7b2c\u4e00\u6b65\u662f\u5229\u7528\u94fe\u5f0f\u6cd5\u5219\uff08chain rule\uff09\u5c06\u8054\u5408\u6982\u7387\u8f6c\u6362\u6210\u6761\u4ef6\u6982\u7387\u7684\u8fde\u4e58\u5f62\u5f0f\uff1a<\/p>\n\n\n\n<p class=\"has-text-align-center\"><em>P(w1,w2,\u2026,wm)=P(w1)P(w2\u2223w1)P(w3\u2223w1,w2)\u22efP(wm\u2223w1,\u2026,wm\u22121)<\/em><\/p>\n\n\n\n<h3 id=\"22-\u9a6c\u5c14\u53ef\u592b\u5047\u8bbethe-markov-assumption\">\u9a6c\u5c14\u53ef\u592b\u5047\u8bbe\uff08The Markov Assumption\uff09<\/h3>\n\n\n\n<p>\u76ee\u524d\uff0c\u8fd9\u4ecd\u7136\u662f\u4e00\u4e2a\u6bd4\u8f83\u68d8\u624b\u7684\u95ee\u9898\uff0c\u56e0\u4e3a\u968f\u7740\u4e0a\u4e0b\u6587\u7684\u4e0d\u65ad\u589e\u52a0\uff0c\u6211\u4eec\u6784\u5efa\u7684\u6a21\u578b\u4e2d\u5c06\u5305\u542b\u8d8a\u6765\u8d8a\u591a\u7684\u53c2\u6570\u3002\u6240\u4ee5\u8fd9\u91cc\uff0c\u6211\u4eec\u91c7\u7528\u4e00\u79cd\u79f0\u4e3a \u201c\u9a6c\u5c14\u53ef\u592b\u5047\u8bbe\u201d \u7684\u7b80\u5316\u5047\u8bbe\uff1a\u67d0\u4e2a\u5355\u8bcd\u51fa\u73b0\u7684\u6982\u7387\u4e0d\u518d\u4f9d\u8d56\u4e8e\u5168\u90e8\u4e0a\u4e0b\u6587\uff0c\u800c\u662f\u53d6\u51b3\u4e8e\u79bb\u5b83\u6700\u8fd1\u7684&nbsp;n&nbsp;\u4e2a\u5355\u8bcd\u3002\u56e0\u6b64\uff0c\u6211\u4eec\u5f97\u5230\uff1a     P(wi\u2223w1,\u2026,wi\u22121)\u2248P(wi\u2223wi\u2212n+1,\u2026,wi\u22121)<\/p>\n\n\n\n<p>\u5bf9\u4e8e\u67d0\u4e2a\u5f88\u5c0f\u7684&nbsp;n\uff1a<\/p>\n\n\n\n<ul><li>\u5f53&nbsp;n=1&nbsp;\u65f6\uff0c\u4e00\u4e2a unigram \u6a21\u578b\uff1aP(w1,w2,\u2026,wm)=\u220fi=1mP(wi)\u5728 unigram \u6a21\u578b\u4e2d\uff0c\u6211\u4eec\u5047\u8bbe\u4e00\u4e2a\u53e5\u5b50\u51fa\u73b0\u7684\u6982\u7387\u7b49\u4e8e\u5176\u4e2d\u6bcf\u4e2a\u5355\u8bcd\u5355\u72ec\u51fa\u73b0\u7684\u6982\u7387\u7684\u4e58\u79ef\uff0c\u8fd9\u610f\u5473\u7740\u6bcf\u4e2a\u5355\u8bcd\u51fa\u73b0\u7684\u6982\u7387\u4e4b\u95f4\u76f8\u4e92\u72ec\u7acb\uff0c\u5373\u6211\u4eec\u5e76\u4e0d\u5173\u5fc3\u6bcf\u4e2a\u5355\u8bcd\u7684\u4e0a\u4e0b\u6587\u3002<\/li><li>\u5f53&nbsp;n=2&nbsp;\u65f6\uff0c\u4e00\u4e2a bigram \u6a21\u578b\uff1aP(w1,w2,\u2026,wm)=\u220fi=1mP(wi\u2223wi\u22121)\u5728 bigram \u6a21\u578b\u4e2d\uff0c\u6211\u4eec\u5047\u8bbe\u53e5\u5b50\u4e2d\u6bcf\u4e2a\u5355\u8bcd\u51fa\u73b0\u7684\u6982\u7387\u90fd\u548c\u5b83\u524d\u4e00\u4e2a\u5355\u8bcd\u51fa\u73b0\u7684\u6982\u7387\u6709\u5173\u3002<\/li><li>\u5f53&nbsp;n=3&nbsp;\u65f6\uff0c\u4e00\u4e2a trigram \u6a21\u578b\uff1aP(w1,w2,\u2026,wm)=\u220fi=1mP(wi\u2223wi\u22122,wi\u22121)\u5728 trigram \u6a21\u578b\u4e2d\uff0c\u6211\u4eec\u5047\u8bbe\u53e5\u5b50\u4e2d\u6bcf\u4e2a\u5355\u8bcd\u51fa\u73b0\u7684\u6982\u7387\u90fd\u548c\u5b83\u524d\u4e24\u4e2a\u5355\u8bcd\u51fa\u73b0\u7684\u6982\u7387\u6709\u5173\u3002<\/li><\/ul>\n\n\n\n<h3 id=\"23-\u6700\u5927\u4f3c\u7136\u4f30\u8ba1\">\u6700\u5927\u4f3c\u7136\u4f30\u8ba1<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#23-%E6%9C%80%E5%A4%A7%E4%BC%BC%E7%84%B6%E4%BC%B0%E8%AE%A1\"><\/a><\/h3>\n\n\n\n<p><strong>\u6211\u4eec\u5982\u4f55\u8ba1\u7b97\u8fd9\u4e9b\u6982\u7387\uff1f<\/strong><\/p>\n\n\n\n<p>\u975e\u5e38\u7b80\u5355\uff0c\u6211\u4eec\u53ea\u9700\u8981\u4e00\u4e2a\u5927\u7684\u7528\u4e8e\u8bad\u7ec3\u7684\u8bed\u6599\u5e93\uff08corpus\uff09\uff0c\u7136\u540e\u6211\u4eec\u5c31\u53ef\u4ee5\u6839\u636e\u8bed\u6599\u5e93\u4e2d\u5404\u4e2a\u5355\u8bcd\u7684\u8ba1\u6570\uff08counts\uff09\uff0c\u5229\u7528\u6700\u5927\u4f3c\u7136\u4f30\u8ba1\u6765\u4f30\u8ba1\u8be5\u5355\u8bcd\u51fa\u73b0\u7684\u6982\u7387\uff1a<\/p>\n\n\n\n<ul><li>\u5bf9\u4e8e unigram \u6a21\u578b\uff1a<\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-18.png\" alt=\"\" class=\"wp-image-18572\" width=\"123\" height=\"47\"\/><\/figure><\/div>\n\n\n\n<p>\u5176\u4e2d\uff0cC&nbsp;\u662f\u4e00\u4e2a\u8ba1\u6570\u51fd\u6570\uff0cC(wi)&nbsp;\u8868\u793a\u5355\u8bcd&nbsp;wi&nbsp;\u5728\u8bed\u6599\u5e93\u4e2d\u51fa\u73b0\u7684\u6b21\u6570\uff0cM&nbsp;\u8868\u793a\u8bed\u6599\u5e93\u4e2d\u6240\u6709\u5355\u8bcd tokens \u7684\u6570\u91cf\u3002<\/p>\n\n\n\n<ul><li>\u5bf9\u4e8e bigram \u6a21\u578b\uff1a<\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-19.png\" alt=\"\" class=\"wp-image-18578\" width=\"185\" height=\"45\"\/><\/figure><\/div>\n\n\n\n<p>\u5176\u4e2d\uff0cC(wi\u22121,wi)&nbsp;\u8868\u793a\u5355\u8bcd&nbsp;wi\u22121&nbsp;\u548c\u5355\u8bcd&nbsp;wi&nbsp;\u524d\u540e\u76f8\u90bb\u4e00\u8d77\u51fa\u73b0\u7684\u6b21\u6570\u3002<\/p>\n\n\n\n<ul><li>\u5bf9\u4e8e n-gram \u6a21\u578b\uff1a<\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-20.png\" alt=\"\" class=\"wp-image-18582\" width=\"310\" height=\"45\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-20.png 420w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-20-300x44.png 300w\" sizes=\"(max-width: 310px) 100vw, 310px\" \/><\/figure><\/div>\n\n\n\n<p>\u540c\u7406\uff0c\u6211\u4eec\u8ba1\u7b97 n-gram \u51fa\u73b0\u7684\u6b21\u6570\uff0c\u9664\u4ee5 (n-1)-gram\uff08\u5373\u4e0a\u4e0b\u6587\uff09\u51fa\u73b0\u7684\u6b21\u6570\u3002<\/p>\n\n\n\n<h3 id=\"24-\u5e8f\u5217\u7684\u5f00\u5934\u548c\u7ed3\u5c3e\u8868\u793a\">\u5e8f\u5217\u7684\u5f00\u5934\u548c\u7ed3\u5c3e\u8868\u793a<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#24-%E5%BA%8F%E5%88%97%E7%9A%84%E5%BC%80%E5%A4%B4%E5%92%8C%E7%BB%93%E5%B0%BE%E8%A1%A8%E7%A4%BA\"><\/a><\/h3>\n\n\n\n<p>\u5728\u6211\u4eec\u8fdb\u5165\u4f8b\u5b50\u4e4b\u524d\uff0c\u6211\u4eec\u9700\u8981\u7528\u4e00\u4e9b\u7279\u6b8a\u7684\u8bb0\u53f7\u8868\u793a\u4e00\u4e2a\u5e8f\u5217\u7684\u5f00\u59cb\u548c\u7ed3\u675f\uff1a<\/p>\n\n\n\n<ul><li>&lt;s&gt;&nbsp;\u8868\u793a\u53e5\u5b50\u7684\u5f00\u59cb<\/li><li>&lt;\/s&gt;&nbsp;\u8868\u793a\u53e5\u5b50\u7684\u7ed3\u675f<\/li><\/ul>\n\n\n\n<h3 id=\"25-trigram-\u4f8b\u5b50\">Trigram \u4f8b\u5b50<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#25-trigram-%E4%BE%8B%E5%AD%90\"><\/a><\/h3>\n\n\n\n<p>\u73b0\u5728\uff0c\u8ba9\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u73a9\u5177\u4f8b\u5b50\uff0c\u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u53ea\u5305\u542b\u4e24\u4e2a\u53e5\u5b50\u7684\u8bed\u6599\u5e93\u3002<\/p>\n\n\n\n<p><strong>\u8bed\u6599\u5e93<\/strong>\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-21.png\" alt=\"\" class=\"wp-image-18589\" width=\"376\" height=\"46\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-21.png 376w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-21-300x37.png 300w\" sizes=\"(max-width: 376px) 100vw, 376px\" \/><\/figure>\n\n\n\n<p>\u53ef\u4ee5\u770b\u5230\uff0c\u6bcf\u4e2a\u53e5\u5b50\u5f00\u5934\u6709\u4e24\u4e2a\u8d77\u59cb\u6807\u8bb0\uff0c\u56e0\u4e3a\u6211\u4eec\u91c7\u7528\u7684\u662f trigram \u6a21\u578b\u3002<\/p>\n\n\n\n<p><strong>\u6211\u4eec\u5e0c\u671b\u77e5\u9053\u4e0b\u9762\u7684\u53e5\u5b50\u5728\u4e00\u4e2a trigram \u6a21\u578b\u4e0b\u7684\u6982\u7387\u662f\u591a\u5c11\uff1f<\/strong><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-22.png\" alt=\"\" class=\"wp-image-18595\" width=\"553\" height=\"141\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-22.png 673w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-22-300x76.png 300w\" sizes=\"(max-width: 553px) 100vw, 553px\" \/><\/figure><\/div>\n\n\n\n<p><strong>\u8bf4\u660e<\/strong>\uff1a<\/p>\n\n\n\n<ul><li>\u9996\u5148\uff0c\u6211\u4eec\u5bf9\u8981\u8ba1\u7b97\u7684\u53e5\u5b50\u7684\u6982\u7387\u6309\u7167 trigram \u6a21\u578b\u62c6\u5206\u6210\u6761\u4ef6\u6982\u7387\u7684\u8fde\u4e58\u5f62\u5f0f\u3002<\/li><li>\u7136\u540e\uff0c\u5bf9\u4e8e\u7b49\u5f0f\u53f3\u8fb9\u7684\u6bcf\u4e00\u4e2a\u6761\u4ef6\u6982\u7387\u9879\uff0c\u6309\u7167 trigram \u6a21\u578b\u4e2d\u7684\u6761\u4ef6\u6982\u7387\u8ba1\u7b97\u516c\u5f0f\uff0c\u5206\u522b\u7edf\u8ba1 \u201c\u5f53\u524d\u5355\u8bcd\u8fde\u540c\u5b83\u7684\u4e0a\u4e0b\u6587\u201d \u4ee5\u53ca \u201c\u5355\u72ec\u7684\u4e0a\u4e0b\u6587\u90e8\u5206\u201d \u5728\u8bed\u6599\u5e93\u4e2d\u51fa\u73b0\u7684\u6b21\u6570\uff0c\u5e76\u5c06\u4e24\u8005\u76f8\u9664\uff0c\u5f97\u5230\u8be5\u9879\u7684\u8ba1\u7b97\u7ed3\u679c\u3002<br>\u4f8b\u5982\uff0c\u5bf9\u4e8e\u4e0a\u9762\u7b49\u5f0f\u53f3\u8fb9\u7b2c\u4e00\u4e2a\u6761\u4ef6\u6982\u7387\u9879\uff0c\u6211\u4eec\u8003\u8651\u53e5\u5b50\u4e2d\u7b2c\u4e00\u4e2a\u5355\u8bcd \u201cyes\u201d \u53ca\u5176\u76f8\u90bb\u7684 bigram \u4e0a\u4e0b\u6587 \u201c&lt;s&gt;&lt;s&gt;\u201d\uff1a<\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-23.png\" alt=\"\" class=\"wp-image-18598\" width=\"315\" height=\"48\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-23.png 384w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-23-300x45.png 300w\" sizes=\"(max-width: 315px) 100vw, 315px\" \/><\/figure><\/div>\n\n\n\n<p>\u53ef\u4ee5\u770b\u5230\uff0c\u5b50\u5e8f\u5217 \u201c&lt;s&gt;&lt;s&gt;yes\u201d \u5728\u8bed\u6599\u5e93\u4e2d\u53ea\u51fa\u73b0\u8fc7&nbsp;1&nbsp;\u6b21\uff1b\u800c\u5b50\u5e8f\u5217 \u201c&lt;s&gt;&lt;s&gt;\u201d \u5728\u8bed\u6599\u5e93\u4e2d\u4e00\u5171\u51fa\u73b0\u4e86&nbsp;2&nbsp;\u6b21\uff0c\u6240\u4ee5\u7b2c\u4e00\u4e2a\u6761\u4ef6\u6982\u7387\u9879\u7684\u7ed3\u679c\u4e3a&nbsp;12\u3002\u5176\u4f59\u5404\u6761\u4ef6\u6982\u7387\u9879\u7684\u8ba1\u7b97\u65b9\u5f0f\u540c\u7406\uff0c\u53e6\u5916\u8bf7\u6ce8\u610f\uff0c\u5728\u8ba1\u7b97\u7b2c\u56db\u4e2a\u6761\u4ef6\u6982\u7387\u9879\u65f6\uff0cbigram \u4e0a\u4e0b\u6587 \u201cnono\u201d \u5728\u8bed\u6599\u5e93\u4e2d\u4e00\u5171\u51fa\u73b0\u4e86&nbsp;5&nbsp;\u6b21\u3002<\/p>\n\n\n\n<h3 id=\"26-n-gram-\u8bed\u8a00\u6a21\u578b\u7684\u4e00\u4e9b\u95ee\u9898\">N-gram \u8bed\u8a00\u6a21\u578b\u7684\u4e00\u4e9b\u95ee\u9898<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#26-n-gram-%E8%AF%AD%E8%A8%80%E6%A8%A1%E5%9E%8B%E7%9A%84%E4%B8%80%E4%BA%9B%E9%97%AE%E9%A2%98\"><\/a><\/h3>\n\n\n\n<ul><li><strong>\u8bed\u8a00\u901a\u5e38\u5177\u6709\u957f\u8ddd\u79bb\u6548\u5e94 \u2014\u2014 \u9700\u8981\u8bbe\u7f6e\u8f83\u5927\u7684&nbsp;n&nbsp;\u503c<\/strong><br>\u6709\u4e9b\u8bcd\u5bf9\u5e94\u7684\u4e0a\u4e0b\u6587\u53ef\u80fd\u51fa\u73b0\u5728\u53e5\u5b50\u4e2d\u8ddd\u79bb\u8be5\u8bcd\u5f88\u8fdc\u7684\u5730\u65b9\uff0c\u8fd9\u610f\u5473\u7740\u5982\u679c\u6211\u4eec\u91c7\u7528\u56fa\u5b9a\u957f\u5ea6\u7684\u4e0a\u4e0b\u6587\uff08\u4f8b\u5982\uff1atrigram \u6a21\u578b\uff09 \uff0c\u6211\u4eec\u53ef\u80fd\u65e0\u6cd5\u6355\u6349\u5230\u8db3\u591f\u7684\u4e0a\u4e0b\u6587\u76f8\u5173\u4fe1\u606f\u3002\u4f8b\u5982\uff1aThe&nbsp;lecture\/s&nbsp;that took place last week&nbsp;was\/were&nbsp;on processing.\u5728\u4e0a\u9762\u7684\u53e5\u5b50\u4e2d\uff0c\u5047\u5982\u6211\u4eec\u8981\u51b3\u5b9a\u7cfb\u52a8\u8bcd&nbsp;be&nbsp;\u662f\u5e94\u8be5\u7528\u7b2c\u4e09\u4eba\u79f0\u5355\u6570\u5f62\u5f0f&nbsp;was&nbsp;\u8fd8\u662f\u590d\u6570\u5f62\u5f0f&nbsp;were\uff0c\u6211\u4eec\u9700\u8981\u56de\u5934\u770b\u53e5\u5b50\u5f00\u5934\u7684\u4e3b\u8bed\u662f&nbsp;lecture&nbsp;\u8fd8\u662f&nbsp;lectures\u3002\u53ef\u4ee5\u770b\u5230\uff0c\u5b83\u4eec\u4e4b\u95f4\u7684\u8ddd\u79bb\u6bd4\u8f83\u8fdc\uff0c\u5982\u679c\u6211\u4eec\u91c7\u7528 bigram \u6216\u8005 trigram \u6a21\u578b\uff0c\u6211\u4eec\u65e0\u6cd5\u5f97\u5230\u76f8\u5173\u7684\u4e0a\u4e0b\u6587\u4fe1\u606f\u6765\u544a\u8bc9\u6211\u4eec\u5f53\u524d\u4f4d\u7f6e\u5e94\u8be5\u7528&nbsp;was&nbsp;\u8fd8\u662f&nbsp;were\u3002\u8fd9\u662f\u6240\u6709\u6709\u9650\u4e0a\u4e0b\u6587\u8bed\u8a00\u6a21\u578b\uff08finite context language models\uff09\u7684\u4e00\u4e2a\u901a\u75c5\u3002<\/li><li><strong>\u8ba1\u7b97\u51fa\u7684\u7ed3\u679c\u7684\u6982\u7387\u901a\u5e38\u4f1a\u975e\u5e38\u5c0f<\/strong><br>\u4f60\u4f1a\u53d1\u73b0\uff0c\u4e00\u8fde\u4e32\u6761\u4ef6\u6982\u7387\u9879\u8fde\u4e58\u5f97\u5230\u7684\u7ed3\u679c\u5f80\u5f80\u4f1a\u975e\u5e38\u5c0f\uff0c\u5bf9\u4e8e\u8fd9\u4e2a\u95ee\u9898\uff0c\u6211\u4eec\u53ef\u4ee5\u91c7\u7528\u53d6\u5bf9\u6570\u8ba1\u7b97 log \u6982\u7387\u6765\u907f\u514d\u6570\u503c\u4e0b\u6ea2\uff08numerical underflow\uff09\u3002<\/li><li><strong>\u5bf9\u4e8e\u4e0d\u5b58\u5728\u4e8e\u8bed\u6599\u5e93\u4e2d\u7684\u8bcd\uff0c\u65e0\u6cd5\u8ba1\u7b97\u5176\u51fa\u73b0\u6982\u7387<\/strong><br>\u5982\u679c\u6211\u4eec\u8981\u8ba1\u7b97\u6982\u7387\u7684\u53e5\u5b50\u4e2d\u5305\u542b\u4e86\u4e00\u4e9b\u6ca1\u6709\u5728\u8bed\u6599\u5e93\u4e2d\u51fa\u73b0\u8fc7\u7684\u5355\u8bcd\uff08\u4f8b\u5982\uff1a\u4eba\u540d\uff09\uff0c\u6211\u4eec\u5e94\u8be5\u600e\u4e48\u529e\uff1f<br><strong>\u4e00\u79cd\u6bd4\u8f83\u7b80\u5355\u7684\u6280\u5de7\u662f\uff0c\u6211\u4eec\u53ef\u4ee5\u7528\u67d0\u79cd\u7279\u6b8a\u7b26\u53f7\uff08\u4f8b\u5982\uff1a&lt;UNK&gt;\uff09\u6765\u8868\u793a\u8fd9\u4e9b\u6240\u8c13\u7684 OOV \u5355\u8bcd\uff08out-of-vocabulary\uff0c\u5373\u4e0d\u5728\u8bcd\u6c47\u8868\u4e2d\u7684\u5355\u8bcd\uff09\uff0c\u5e76\u4e14\u5c06\u8bed\u6599\u5e93\u4e2d\u4e00\u4e9b\u975e\u5e38\u4f4e\u9891\u7684\u5355\u8bcd\u90fd\u66ff\u6362\u4e3a\u8fd9\u79cd\u8868\u793a\u672a\u77e5\u5355\u8bcd\u7684\u7279\u6b8a token\u3002<\/strong><\/li><li><strong>\u51fa\u73b0\u5728\u65b0\u7684\u4e0a\u4e0b\u6587\uff08context\uff09\u4e2d\u7684\u5355\u8bcd<\/strong><br>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u4efb\u4f55\u6211\u4eec\u4e4b\u524d\u6ca1\u6709\u5728\u8bed\u6599\u5e93\u4e2d\u89c1\u8fc7\u7684 n-gram \u7684\u8ba1\u6570\u90fd\u4e3a&nbsp;0\uff0c\u8fd9\u5c06\u5bfc\u81f4\u8ba1\u7b97\u51fa\u7684&nbsp;<strong>\u6574\u4e2a\u53e5\u5b50\u7684\u6982\u7387\u4e3a&nbsp;0<\/strong>\u3002\u8fd9\u4e2a\u95ee\u9898\u548c\u524d\u9762\u7684 OOV \u5355\u8bcd\u7684\u95ee\u9898\u7c7b\u4f3c\uff0c<strong>\u6211\u4eec\u7684\u8bed\u6599\u5e93\u4e2d\u53ef\u80fd\u5df2\u7ecf\u5305\u542b\u4e86\u8fd9\u4e9b\u5355\u8bcd\uff0c\u4f46\u662f\u5e76\u6ca1\u6709\u5305\u542b\u8be5\u5355\u8bcd\u5728\u65b0\u53e5\u5b50\u4e2d\u5bf9\u5e94\u7684\u7279\u5b9a\u7684 n-gram\uff08\u5373\u4e0a\u4e0b\u6587\u4fe1\u606f\uff09\u3002<\/strong>\u8fd9\u610f\u5473\u7740\u8be5\u5355\u8bcd\u5728\u65b0\u7684\u53e5\u5b50\u4e2d\u5bf9\u5e94 n-gram \u5bf9\u4e8e\u8bed\u8a00\u6a21\u578b\u6765\u8bf4\u662f\u5168\u65b0\u7684\uff0c\u800c\u4e14\u56e0\u4e3a n-gram \u7684\u7ec4\u5408\u5b58\u5728\u5982\u6b64\u591a\u7684\u53ef\u80fd\u6027\uff0c\u4ee5\u81f3\u4e8e\u8bed\u6599\u5e93\u5f88\u96be\u5c06\u6240\u6709\u7684\u53ef\u80fd\u6027\u90fd\u8986\u76d6\u5230\u3002\u4f8b\u5982\uff1a\u5047\u8bbe\u6211\u4eec\u6784\u5efa\u4e86\u4e00\u4e2a five-gram \u8bed\u8a00\u6a21\u578b\uff0c\u6211\u4eec\u7684\u8bed\u6599\u5e93\u4e2d\u4e00\u5171\u6709 20000 \u4e2a\u8bcd\u6c47\uff0c\u90a3\u4e48\u4e00\u5171\u5b58\u5728\u591a\u5c11\u79cd\u53ef\u80fd\u7684 five -gram \u7ec4\u5408\uff1f\u7b54\u6848\u662f\uff1a200005\u3002\u8fd9\u662f\u4e00\u4e2a\u975e\u5e38\u975e\u5e38\u5927\u7684\u6570\u5b57\uff0c\u4ee5\u81f3\u4e8e\u65e0\u8bba\u6211\u4eec\u7684\u8bad\u7ec3\u8bed\u6599\u5e93\u6709\u591a\u5927\uff0c\u90fd\u4e0d\u53ef\u80fd\u6355\u6349\u5230\u6240\u6709\u7684\u53ef\u80fd\u6027\u7ec4\u5408\u3002\u8fd9\u662f\u4e00\u4e2a\u76f8\u5f53\u5e38\u89c1\u7684\u95ee\u9898\uff0c\u5e76\u4e14\u5f88\u91cd\u8981\u3002\u5982\u679c\u6211\u4eec\u56de\u987e\u4e00\u4e0b\u94fe\u5f0f\u6cd5\u5219\uff0c<strong>\u53ef\u4ee5\u770b\u5230\u6240\u6709\u7684\u6761\u4ef6\u6982\u7387\u90fd\u8fde\u4e58\u5728\u4e00\u8d77\uff0c\u6240\u4ee5\u53ea\u8981\u5176\u4e2d\u67d0\u4e00\u9879\u5728\u8ba1\u7b97\u5b50\u5e8f\u5217\u65f6 n-gram \u7684\u8ba1\u6570\u4e3a&nbsp;0\uff0c\u90a3\u4e48\u6700\u7ec8 \u8ba1\u7b97\u51fa\u7684\u6574\u4e2a\u53e5\u5b50\u7684\u6982\u7387\u5c31\u4f1a\u4e3a&nbsp;0\u3002\u4e3a\u6b64\uff0c\u6211\u4eec\u9700\u8981\u5bf9\u8bed\u8a00\u6a21\u578b\u8fdb\u884c&nbsp;\u5e73\u6ed1\u5904\u7406\uff08smoothing\uff09<\/strong>\u3002<\/li><\/ul>\n\n\n\n<h2 id=\"3-\u5e73\u6ed1\u5904\u7406\">\u5e73\u6ed1\u5904\u7406<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#3-%E5%B9%B3%E6%BB%91%E5%A4%84%E7%90%86\"><\/a><\/h2>\n\n\n\n<ul><li>\u57fa\u672c\u601d\u60f3\uff1a\u7ed9\u4e4b\u524d\u6ca1\u6709\u89c1\u8fc7\u7684\u4e8b\u4ef6\u8d4b\u4e88\u6982\u7387\u3002<\/li><li>\u5fc5\u987b\u9644\u52a0\u4e00\u4e2a\u7ea6\u675f\u6761\u4ef6\uff1aP(everything)=1<\/li><li>\u6709\u5f88\u591a\u4e0d\u540c\u79cd\u7c7b\u7684\u5e73\u6ed1\u5904\u7406\u65b9\u6cd5\uff1a<ul><li>\u62c9\u666e\u62c9\u65af\u5e73\u6ed1\uff08Laplacian smoothing\uff0c\u53c8\u79f0 Add-one smoothing\uff0c\u5373 \u201c\u52a0\u4e00\u201d \u5e73\u6ed1\uff09<\/li><li>\u201c\u52a0 k\u201d \u5e73\u6ed1\uff08Add-k smoothing\uff09<\/li><li>Jelinek-Mercer \u63d2\u503c\uff08\u53c8\u79f0 \u7ebf\u6027\u63d2\u503c\u5e73\u6ed1\uff09<\/li><li>\u5361\u8328\u56de\u9000\u6cd5\uff08Katz backoff\uff09<\/li><li>\u7edd\u5bf9\u6298\u6263\uff08Absolute discounting\uff09<\/li><li>Kneser-Ney<\/li><li>\u2026\u2026<\/li><\/ul><\/li><\/ul>\n\n\n\n<h3 id=\"31-\u62c9\u666e\u62c9\u65af\u5e73\u6ed1\u52a0\u4e00-\u5e73\u6ed1\">\u62c9\u666e\u62c9\u65af\u5e73\u6ed1\uff08\u201c\u52a0\u4e00\u201d \u5e73\u6ed1\uff09<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#31-%E6%8B%89%E6%99%AE%E6%8B%89%E6%96%AF%E5%B9%B3%E6%BB%91%E5%8A%A0%E4%B8%80-%E5%B9%B3%E6%BB%91\"><\/a><\/h3>\n\n\n\n<p>\u7b80\u5355\u601d\u60f3\uff1a\u5047\u88c5\u6211\u4eec\u770b\u5230\u7684\u6bcf\u4e00\u4e2a n-gram \u90fd\u6bd4\u5b83\u4eec\u5b9e\u9645\u51fa\u73b0\u7684\u6b21\u6570\u591a&nbsp;1&nbsp;\u6b21\u3002<\/p>\n\n\n\n<ul><li>\u8fd9\u610f\u5473\u7740\u5373\u4f7f\u662f\u90a3\u4e9b\u6211\u4eec\u5728\u8bed\u6599\u5e93\u4e2d\u6ca1\u6709\u89c1\u8fc7\u7684 n-gram\uff0c\u6211\u4eec\u4e5f\u5c06\u5b83\u4eec\u51fa\u73b0\u7684\u6b21\u6570\u8bb0\u4e3a&nbsp;1&nbsp;\u6b21\u3002\u6240\u4ee5\u5bf9\u4e8e\u4e00\u4e2a\u65b0\u53e5\u5b50\u4e2d\u7684\u4efb\u4f55\u4e1c\u897f\u90fd\u81f3\u5c11\u6709&nbsp;1&nbsp;\u6b21\u8ba1\u6570\u3002<\/li><li>\u5bf9\u4e8e unigram \u6a21\u578b\uff08V=&nbsp;\u8bcd\u6c47\u8868\uff09\uff1a<\/li><\/ul>\n\n\n\n<p>\u5728\u4e4b\u524d\u7684\u6a21\u578b\u4e2d\uff0c\u6211\u4eec\u53ea\u662f\u7b80\u5355\u7684\u8ba1\u7b97\u5355\u8bcd&nbsp;wi&nbsp;\u5728\u8bed\u6599\u5e93\u4e2d\u51fa\u73b0\u7684\u6b21\u6570&nbsp;C(wi)&nbsp;\uff0c\u7136\u540e\u9664\u4ee5\u8bed\u6599\u5e93\u4e2d\u6240\u6709\u5355\u8bcd tokens \u7684\u6570\u91cf&nbsp;M\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-24.png\" alt=\"\" class=\"wp-image-18603\" width=\"173\" height=\"47\"\/><\/figure><\/div>\n\n\n\n<p>\u73b0\u5728\uff0c\u5bf9\u4e8e\u5206\u5b50\u800c\u8a00\uff0c\u6211\u4eec\u603b\u662f\u5728\u5b83\u6b64\u524d\u7684\u57fa\u7840\u4e0a\u52a0\u4e0a&nbsp;1\u3002\u7136\u540e\uff0c\u4e3a\u4e86\u4fdd\u8bc1\u5b83\u4ecd\u7136\u662f\u4e00\u4e2a\u5408\u6cd5\u7684\u6982\u7387\u5206\u5e03\uff0c\u5373\u5355\u8bcd&nbsp;wi&nbsp;\u904d\u5386\u8bcd\u6c47\u8868\u4e2d\u6240\u6709\u53ef\u80fd\u60c5\u51b5\u7684\u7684\u6982\u7387\u4e4b\u548c&nbsp;\u2211i=1|V|P(wi)=1\uff0c\u6211\u4eec\u9700\u8981\u5728\u6b64\u524d\u5206\u6bcd&nbsp;M&nbsp;\u7684\u57fa\u7840\u4e0a\u52a0\u4e0a\u8bcd\u6c47\u8868\u7684\u957f\u5ea6&nbsp;|V|\uff08\u5373\u8bed\u6599\u5e93\u4e2d\u6240\u6709\u5355\u8bcd types \u7684\u603b\u6570\uff09\u3002<\/p>\n\n\n\n<ul><li>\u5bf9\u4e8e bigram \u6a21\u578b\uff1a<\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-25.png\" alt=\"\" class=\"wp-image-18608\" width=\"248\" height=\"44\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-25.png 321w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-25-300x54.png 300w\" sizes=\"(max-width: 248px) 100vw, 248px\" \/><\/figure><\/div>\n\n\n\n<p>\u540c\u6837\u5730\uff0c\u6211\u4eec\u5728\u4e4b\u524d\u5206\u5b50\u7684\u57fa\u7840\u4e0a\u52a0&nbsp;1\uff0c\u5728\u5206\u6bcd\u7684\u57fa\u7840\u4e0a\u52a0&nbsp;|V|\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u73b0\u5728\uff0c\u6211\u4eec\u89e3\u51b3\u4e86\u4e4b\u524d\u65b0\u53e5\u5b50\u4e2d\u7684\u672a\u77e5\u5355\u8bcd\u6216\u8005 n-gram \u7684\u8ba1\u6570\u4e3a&nbsp;0&nbsp;\u4ece\u800c\u5bfc\u81f4\u6700\u7ec8\u8ba1\u7b97\u51fa\u7684\u6982\u7387\u4e3a&nbsp;0&nbsp;\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n<h3 id=\"33-\u52a0-k-\u5e73\u6ed1\">\u201c\u52a0 k\u201d \u5e73\u6ed1<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#33-%E5%8A%A0-k-%E5%B9%B3%E6%BB%91\"><\/a><\/h3>\n\n\n\n<ul><li><strong>\u201c\u52a0\u4e00\u201d \u5f80\u5f80\u592a\u591a\u4e86<\/strong><br>\u4f46\u662f\u5f88\u591a\u65f6\u5019\uff0c\u52a0&nbsp;1&nbsp;\u4f1a\u663e\u5f97\u592a\u591a\u4e86\uff0c\u6211\u4eec\u5e76\u4e0d\u60f3\u6bcf\u6b21\u90fd\u52a0&nbsp;1\uff0c\u56e0\u4e3a\u8fd9\u4f1a\u5bfc\u81f4\u539f\u672c\u7684\u7f55\u89c1\u4e8b\u4ef6\u53ef\u80fd\u53d8\u5f97\u6709\u70b9\u8fc7\u4e8e\u9891\u7e41\u4e86\u3002\u5e76\u4e14\u6211\u4eec\u4e22\u5f03\u4e86\u6240\u89c2\u6d4b\u7684 n-gram \u7684\u592a\u591a\u6709\u6548\u8ba1\u6570\u3002<\/li><li><strong>\u7528 \u201c\u52a0 k\u201d \u6765\u4ee3\u66ff \u201c\u52a0\u4e00\u201d<\/strong><br>\u8fd9\u79cd\u65b9\u5f0f\u4e5f\u88ab\u79f0\u4e3a&nbsp;<strong>Lidstone \u5e73\u6ed1\uff08Lidstone Smoothing\uff09<\/strong>\u3002<\/li><li><strong>\u5bf9\u4e8e trigram \u6a21\u578b\uff0c\u516c\u5f0f\u5982\u4e0b<\/strong>\uff1a<\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-26.png\" alt=\"\" class=\"wp-image-18612\" width=\"319\" height=\"40\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-26.png 412w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-26-300x38.png 300w\" sizes=\"(max-width: 319px) 100vw, 319px\" \/><\/figure><\/div>\n\n\n\n<p>\u53ef\u4ee5\u770b\u5230\uff0c\u548c \u201c\u52a0\u4e00\u201d \u5e73\u6ed1\u7c7b\u4f3c\uff0c\u53ea\u662f\u6211\u4eec\u5c06\u5206\u5b50\u4e2d\u7684\u52a0&nbsp;1&nbsp;\u53d8\u6210\u4e86\u52a0&nbsp;k\uff0c\u5e76\u4e14\u4e3a\u4e86\u6ee1\u8db3\u5355\u8bcd&nbsp;wi&nbsp;\u904d\u5386\u8bcd\u6c47\u8868\u4e2d\u6240\u6709\u53ef\u80fd\u60c5\u51b5\u7684\u6982\u7387\u4e4b\u548c\u4e3a&nbsp;1\uff0c\u6211\u4eec\u5728\u5206\u6bcd\u4e2d\u7684&nbsp;|V|&nbsp;\u524d\u9762\u4e58\u4e86\u4e00\u4e2a\u7cfb\u6570&nbsp;k\u3002<\/p>\n\n\n\n<ul><li><strong>\u5fc5\u987b\u9009\u62e9\u4e00\u4e2a&nbsp;k<\/strong><br>\u4e8b\u5b9e\u4e0a\uff0c\u5982\u4f55\u9009\u62e9\u4e00\u4e2a\u5408\u9002\u7684&nbsp;k&nbsp;\u503c\u5bf9\u4e8e\u6a21\u578b\u5f71\u54cd\u975e\u5e38\u5927\u3002k&nbsp;\u5728\u8fd9\u91cc\u5b9e\u9645\u4e0a\u662f\u4e00\u4e2a\u8d85\u53c2\u6570\uff0c\u6211\u4eec\u9700\u8981\u5c1d\u8bd5\u5bf9\u5176\u8fdb\u884c\u8c03\u6574\u4ee5\u4fbf\u627e\u5230\u4e00\u4e2a\u4f7f\u6a21\u578b\u8868\u73b0\u6bd4\u8f83\u597d\u7684&nbsp;k&nbsp;\u503c\u3002<\/li><\/ul>\n\n\n\n<h3 id=\"35-absolute-discounting-\u5e73\u6ed1\">&nbsp;Absolute Discounting \u5e73\u6ed1<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#35-absolute-discounting-%E5%B9%B3%E6%BB%91\"><\/a><\/h3>\n\n\n\n<p>\u53e6\u5916\u4e00\u79cd\u66f4\u597d\u7684\u65b9\u6cd5\u662f\u91c7\u7528&nbsp;<strong>\u7edd\u5bf9\u6298\u6263\u5e73\u6ed1\uff08Absolute Discounting\uff09<\/strong>\uff1a<\/p>\n\n\n\n<ul><li>\u4ece\u6bcf\u4e2a&nbsp;<strong>\u89c2\u6d4b\u5230\u7684 n-gram<\/strong>&nbsp;\u8ba1\u6570\u4e2d \u201c\u501f\u201d \u4e00\u4e2a&nbsp;<strong>\u56fa\u5b9a\u7684\u6982\u7387\u8d28\u91cf\uff08a fixed probability mass\uff09<\/strong>&nbsp;d\u3002<\/li><li>\u7136\u540e\u5c06\u5176&nbsp;<strong>\u91cd\u65b0\u5206\u914d\uff08redistributes\uff09<\/strong>&nbsp;\u5230&nbsp;<strong>\u672a\u77e5\u7684 n-grams<\/strong>&nbsp;\u4e0a\u3002<\/li><\/ul>\n\n\n\n<h3 id=\"36-backoff-\u5e73\u6ed1\">Backoff \u5e73\u6ed1<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#36-backoff-%E5%B9%B3%E6%BB%91\"><\/a><\/h3>\n\n\n\n<p>\u57fa\u672c\u4e0a\uff0c\u6211\u4eec\u4f1a\u6309\u7167\u4e0d\u65ad\u6539\u8fdb\u7684\u987a\u5e8f\u6765\u4ecb\u7ecd\u5404\u79cd\u5e73\u6ed1\u5904\u7406\u65b9\u5f0f\u7684\u53d8\u4f53\uff0c\u7531\u6b64\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u5230\u5bf9\u4e8e\u8fd9\u4e9b\u5e73\u6ed1\u65b9\u5f0f\u7684\u8bc4\u4f30\u3002\u73b0\u5728\uff0c\u6211\u4eec\u7ee7\u7eed\u4ecb\u7ecd\u53e6\u4e00\u79cd\u66f4\u597d\u7684\u5e73\u6ed1\u65b9\u5f0f\uff1a<strong>Backoff \u5e73\u6ed1<\/strong>\u3002<\/p>\n\n\n\n<ul><li>\u5728\u4e4b\u524d\u7684 Absolute Discounting \u5e73\u6ed1\u4e2d\uff0c\u6211\u4eec\u4ece\u89c2\u6d4b\u5230\u7684\u6bcf\u4e2a n-gram \u8ba1\u6570\u4e2d \u201c\u501f\u6765\u201d \u4e00\u4e2a\u56fa\u5b9a\u7684\u6982\u7387\u8d28\u91cf\uff0c\u5e76\u5c06\u5b83\u4eec\u91cd\u65b0&nbsp;<strong>\u5e73\u5747<\/strong>&nbsp;\u5206\u914d\u7ed9\u6240\u6709\u7684\u672a\u77e5 n-grams\u3002<\/li><li><strong>Katz Backoff<\/strong>\uff1a\u6982\u7387\u8d28\u91cf\u7684\u91cd\u65b0\u5206\u914d\u662f\u57fa\u4e8e\u4e00\u4e2a&nbsp;<strong>\u4f4e\u9636\uff08lower order\uff09<\/strong>&nbsp;\u6a21\u578b\uff08\u4f8b\u5982\uff1aunigram \u6a21\u578b\uff09<\/li><\/ul>\n\n\n\n<p>\u4f8b\u5982\uff0c\u5047\u8bbe\u6211\u4eec\u73b0\u5728\u6709\u4e00\u4e2a bigram \u6a21\u578b\uff0c\u5f53\u6211\u4eec\u5c06\u6982\u7387\u8d28\u91cf\u91cd\u65b0\u5206\u914d\u5230\u672a\u77e5\u7684 bi-grams \u65f6\uff0c\u6211\u4eec\u5c06\u57fa\u4e8e\u4e0a\u4e0b\u6587\u5355\u8bcd\u7684 unigram \u6982\u7387\u8fdb\u884c\u91cd\u65b0\u5206\u914d\u3002\u56e0\u4e3a\u6bd4\u4f8b\u5f88\u7b80\u5355\uff0c\u5982\u679c\u6211\u4eec\u770b\u5230\u4e0a\u4e0b\u6587\u51fa\u73b0\u6b21\u6570\u8d8a\u591a\uff0c\u6211\u4eec\u5c31\u7ed9\u5b83\u66f4\u9ad8\u7684\u6743\u91cd\u3002<\/p>\n\n\n\n<p>\u5bf9\u4e8e\u4e00\u4e2a bigram \u6a21\u578b\uff0c\u5b83\u7684&nbsp;<strong>Katz Backoff \u5e73\u6ed1\u7684\u6982\u7387\u516c\u5f0f<\/strong>&nbsp;\u5982\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" width=\"747\" height=\"511\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-27.png\" alt=\"\" class=\"wp-image-18620\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-27.png 747w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-27-300x205.png 300w\" sizes=\"(max-width: 747px) 100vw, 747px\" \/><\/figure>\n\n\n\n<p>\u6211\u4eec\u4e3a\u4ec0\u4e48\u5c06\u8fd9\u79cd\u65b9\u5f0f\u79f0\u4e3a Backoff\uff08\u56de\u9000\uff09 \u5462\uff1f<\/p>\n\n\n\n<p>\u56e0\u4e3a\u6211\u4eec\u5728\u78b0\u5230\u672a\u77e5\u7684 n-grams \u7684\u65f6\u5019\u4f1a\u5c06\u539f\u6765\u7684\u6a21\u578b\u56de\u9000\u5230\u4e00\u4e2a\u66f4\u4f4e\u9636\u7684 (n-1)-gram \u6a21\u578b\uff1a\u5bf9\u4e8e\u4e00\u4e2a bigram \u6a21\u578b\uff0c\u6211\u4eec\u5728\u8ba1\u7b97\u672a\u77e5 bi-grams \u7684\u6982\u7387\u65f6\u5c06\u56de\u9000\u5230 unigram \u6a21\u578b\uff1b\u800c\u5bf9\u4e8e\u4e00\u4e2a trigram \u6a21\u578b\uff0c\u6211\u4eec\u5728\u8ba1\u7b97\u672a\u77e5 tri-grams \u7684\u65f6\u5019\u5c06\u56de\u9000\u5230 bigram \u6a21\u578b\u3002\u6240\u4ee5\uff0c\u6211\u4eec\u603b\u662f\u53ea\u56de\u9000\u4e00\u6b65\u3002<\/p>\n\n\n\n<h3 id=\"38-kneser-ney-\u5e73\u6ed1\">&nbsp;Kneser-Ney \u5e73\u6ed1<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#38-kneser-ney-%E5%B9%B3%E6%BB%91\"><\/a><\/h3>\n\n\n\n<p>\u73b0\u5728\uff0c\u6211\u4eec\u5c06\u4ecb\u7ecd\u4e00\u79cd\u6bd4 Katz Backoff \u66f4\u597d\u7684\u5e73\u6ed1\u5904\u7406\u65b9\u5f0f\uff1a<strong>Kneser-Ney \u5e73\u6ed1<\/strong><\/p>\n\n\n\n<ul><li>\u6982\u7387\u8d28\u91cf\u5206\u914d\u57fa\u4e8e\u5f53\u524d\u5355\u8bcd&nbsp;w&nbsp;\u51fa\u73b0\u5728&nbsp;<strong>\u4e0d\u540c\u4e0a\u4e0b\u6587<\/strong>&nbsp;\u4e2d\u7684\u6b21\u6570\u3002<br>\u5bf9\u4e8e\u6982\u7387\u8d28\u91cf\u91cd\u65b0\u5206\u914d\u7684\u95ee\u9898\uff0c\u76f8\u6bd4 Katz Backoff \u4e2d\u53ea\u662f\u7b80\u5355\u5730\u57fa\u4e8e\u4f4e\u9636\u6a21\u578b\uff0cKneser-Ney \u5e73\u6ed1\u91c7\u7528\u7684\u65b9\u6cd5\u662f\u57fa\u4e8e\u5f53\u524d\u5355\u8bcd&nbsp;w&nbsp;\u5728\u591a\u5c11\u4e2a&nbsp;<strong>\u4e0d\u540c\u7684\u4e0a\u4e0b\u6587<\/strong>&nbsp;\u4e2d\u51fa\u73b0\u8fc7\uff0c\u6216\u8005\u8bf4\u662f\u57fa\u4e8e\u8be5\u5355\u8bcd\u7684&nbsp;<strong>\u591a\u529f\u80fd\u6027\uff08versatility\uff09<\/strong>\u3002<br>\u56de\u5fc6\u524d\u9762&nbsp;\u201cglasses\u201d \u548c \u201cFrancisco\u201d \u7684\u4f8b\u5b50\uff0c\u5176\u4e2d \uff0c\u201cFrancisco\u201d \u662f\u4e00\u4e2a\u975e\u5e38\u7279\u6b8a\u7684\u8bcd\uff0c\u5b83\u7684 versatility \u975e\u5e38\u4f4e\uff0c\u56e0\u4e3a\u5b83\u5f88\u53ef\u80fd\u53ea\u5728\u4e0a\u4e0b\u6587\u5355\u8bcd \u201cSan\u201d \u540e\u9762\u51fa\u73b0\u8fc7\u3002\u56e0\u6b64\uff0c\u5bf9\u4e8e\u5176\u4ed6\u7edd\u5927\u591a\u6570\u7684\u4e0a\u4e0b\u6587\u5355\u8bcd\uff0c\u5b83\u4eec\u540e\u9762\u90fd\u4e0d\u592a\u53ef\u80fd\u51fa\u73b0 \u201cFrancisco\u201d \u8fd9\u4e2a\u8bcd\u3002\u800c\u76f8\u6bd4\u4e4b\u4e0b\uff0c\u201cglasses\u201d \u8fd9\u4e2a\u8bcd\u5177\u6709\u8f83\u9ad8\u7684 versatility\uff0c\u5b83\u53ef\u80fd\u5728\u5f88\u591a\u4e0d\u540c\u7684\u4e0a\u4e0b\u6587\u5355\u8bcd\u4e4b\u540e\u90fd\u51fa\u73b0\u8fc7\u3002<\/li><li>\u8fd9\u79cd\u5ea6\u91cf\u88ab\u79f0\u4e3a&nbsp;<strong>\u591a\u529f\u80fd\u6027\uff08versatility\uff09<\/strong>&nbsp;\u6216\u8005&nbsp;<strong>\u5ef6\u7eed\u6982\u7387\uff08continuation probability\uff09<\/strong><\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-28.png\" alt=\"\" class=\"wp-image-18624\" width=\"617\" height=\"285\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-28.png 670w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-28-300x138.png 300w\" sizes=\"(max-width: 617px) 100vw, 617px\" \/><\/figure>\n\n\n\n<p>\u53ef\u4ee5\u770b\u5230\uff0c\u5bf9\u4e8e\u89c2\u6d4b\u5230\u7684 n-grams\uff0cKneser-Ney \u6982\u7387\u548c Katz Backoff \u6982\u7387\u4e24\u8005\u662f\u76f8\u540c\u7684\u3002\u800c\u5bf9\u4e8e\u90a3\u4e9b\u672a\u77e5\u7684 n-grams\uff0cKneser-Ney \u6982\u7387\u4e2d\u4ece\u89c2\u6d4b n-grams \u4e2d \u201c\u501f\u6765\u201d \u7684\u6982\u7387\u8d28\u91cf&nbsp;\u03b1(wi\u22121)&nbsp;\u4e0e\u4e4b\u524d\u4e00\u6837\u4fdd\u6301\u4e0d\u53d8\uff0c\u800c\u4e4b\u524d\u5173\u4e8e\u4f4e\u9636\u6a21\u578b&nbsp;P(wi)&nbsp;\u7684\u90e8\u5206\u5219\u7531\u6211\u4eec\u6240\u8bf4\u7684\u5ef6\u7eed\u6982\u7387&nbsp;Pcont(wi)&nbsp;\u6765\u66ff\u4ee3\u3002<\/p>\n\n\n\n<p>\u5728\u5ef6\u7eed\u6982\u7387&nbsp;Pcont(wi)&nbsp;\u7684\u8ba1\u7b97\u516c\u5f0f\u4e2d\uff1a\u5206\u5b50\u90e8\u5206\u8ba1\u7b97\u7684\u662f\u4e00\u5171\u6709\u591a\u5c11\u4e2a&nbsp;<strong>\u552f\u4e00<\/strong>&nbsp;\u7684\u4e0a\u4e0b\u6587\u5355\u8bcd&nbsp;wi\u22121&nbsp;\u548c\u5f53\u524d\u5355\u8bcd&nbsp;wi&nbsp;\u5171\u540c\u51fa\u73b0\u8fc7\uff08co-occurrence\uff09\uff1b\u800c\u5206\u6bcd\u90e8\u5206\u5c31\u662f\u5c06\u6240\u6709\u53ef\u80fd\u7684\u5355\u8bcd&nbsp;wi&nbsp;\u5bf9\u5e94\u7684\u4e0d\u540c\u5171\u73b0\u4e0a\u4e0b\u6587\u5355\u8bcd\u6570\u91cf\uff08\u5373\u5206\u5b50\u90e8\u5206\uff09\u8fdb\u884c\u4e00\u4e2a\u7d2f\u52a0\u3002<\/p>\n\n\n\n<h3 id=\"39-interpolation\">Interpolation<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#39-interpolation\"><\/a><\/h3>\n\n\n\n<p>\u6211\u4eec\u5c06\u4ecb\u7ecd\u6700\u540e\u4e00\u79cd\u4e5f\u662f\u6700\u597d\u7684\u4e00\u79cd\u5e73\u6ed1\u5904\u7406\u65b9\u5f0f\uff1a<strong>\u63d2\u503c\uff08Interpolation\uff09<\/strong><\/p>\n\n\n\n<ul><li><strong>\u5c06\u4e0d\u540c\u9636\u6570\u7684 n-gram \u6a21\u578b\u7ed3\u5408\u8d77\u6765<\/strong>&nbsp;\u7684\u66f4\u597d\u7684\u5e73\u6ed1\u65b9\u5f0f\u3002<br>\u6211\u4eec\u5728\u524d\u9762\u63d0\u5230\u8fc7\u7684 Katz Backoff \u5e73\u6ed1\uff1a\u5bf9\u4e8e\u4e00\u4e2a trigram \u6a21\u578b\uff0c\u5982\u679c\u6211\u4eec\u9047\u5230\u4e86\u4e00\u4e9b\u672a\u77e5\u7684 tri-grams\uff0c\u6211\u4eec\u5c06\u56de\u9000\u5230\u4e00\u4e2a\u4f4e\u9636\u6a21\u578b\u3002<br>\u4f46\u662f\u4e00\u79cd\u66f4\u597d\u7684\u505a\u6cd5\u662f\uff1a\u5c06\u4e0d\u540c\u9636\u6570\u7684 n-gram \u6a21\u578b\u7ed3\u5408\u8d77\u6765\u3002<\/li><li><strong>\u9010\u6b65\u7f29\u77ed\u7684\u4e0a\u4e0b\u6587\u7684\u6982\u7387\u52a0\u6743\u6c42\u548c<\/strong><br>\u4f8b\u5982\uff0c\u5bf9\u4e8e\u4e00\u4e2a trigram \u6a21\u578b\uff0c\u6211\u4eec\u8ba1\u7b97\u672a\u77e5 tri-grams \u7684\u5e73\u6ed1\u6982\u7387\u65f6\u4f1a\u8d2f\u7a7f trigram\u3001bigram \u548c unigram \u4e09\u79cd\u9636\u6570\u7684\u6a21\u578b\u3002<\/li><li><strong>\u4e00\u4e2a trigram \u6a21\u578b\u4e0b\u7684 Interpolation \u5e73\u6ed1\u6982\u7387<\/strong>\uff1a<\/li><\/ul>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-29.png\" alt=\"\" class=\"wp-image-18628\" width=\"535\" height=\"121\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-29.png 670w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-29-300x68.png 300w\" sizes=\"(max-width: 535px) 100vw, 535px\" \/><\/figure><\/div>\n\n\n\n<p><br>\u6211\u4eec\u53ef\u4ee5\u6309\u7167\u4e0b\u9762\u7684\u6b65\u9aa4\u8ba1\u7b97\u5355\u8bcd&nbsp;wm&nbsp;\u5728\u4e0a\u4e0b\u6587\u5355\u8bcd \u201cwm\u22122\u201d \u548c \u201cwm\u22121\u201d \u4e4b\u540e\u51fa\u73b0\u7684 Interpolation \u5e73\u6ed1\u6982\u7387\uff1a<\/p>\n\n\n\n<ul><li>\u9996\u5148\u8ba1\u7b97 trigram \u6982\u7387&nbsp;P3\u2217\uff0c\u5e76\u5c06\u5176\u4e58\u4ee5\u4e00\u4e2a\u7cfb\u6570&nbsp;\u03bb3\uff1b<\/li><li>\u7136\u540e\u8ba1\u7b97 bigram \u6982\u7387&nbsp;P2\u2217\uff0c\u5e76\u5c06\u5176\u4e58\u4ee5\u4e00\u4e2a\u7cfb\u6570&nbsp;\u03bb2\uff1b<\/li><li>\u7136\u540e\u8ba1\u7b97 unigram \u6982\u7387&nbsp;P1\u2217\uff0c\u5e76\u5c06\u5176\u4e58\u4ee5\u4e00\u4e2a\u7cfb\u6570&nbsp;\u03bb1\uff1b<\/li><li>\u6700\u540e\uff0c\u5c06\u4e09\u8005\u76f8\u52a0\u5f97\u5230\u6700\u7ec8\u7ed3\u679c\u3002<\/li><\/ul>\n\n\n\n<p>\u5e76\u4e14\uff0c\u4e3a\u4e86\u4fdd\u8bc1\u6240\u5f97\u5230\u7684\u4ecd\u7136\u662f\u4e00\u4e2a\u5408\u6cd5\u7684\u6982\u7387\u5206\u5e03\uff0c\u6211\u4eec\u9700\u8981\u6ee1\u8db3\u6240\u6709&nbsp;\u03bb&nbsp;\u4e4b\u548c\u4e3a 1\u3002\u6b64\u5916\uff0c\u8fd9\u4e9b&nbsp;\u03bb&nbsp;\u7684\u503c\u751a\u81f3\u5e76\u4e0d\u9700\u8981\u6211\u4eec\u624b\u52a8\u8bbe\u7f6e\uff0c\u800c\u662f\u7531\u6a21\u578b\u901a\u8fc7\u4e00\u4e9b\u7559\u5b58\u6570\u636e\u5b66\u4e60\u5230\u7684\uff0c\u56e0\u4e3a\u6211\u4eec\u60f3\u77e5\u9053\u5bf9\u4e8e\u8fd9\u4e9b\u4e0d\u540c\u9636\u6570\u7684\u6a21\u578b\uff0c\u4ec0\u4e48\u6837\u7684 Interpolation \u65b9\u5f0f\u662f\u6700\u9ad8\u6548\u7684\u3002<\/p>\n\n\n\n<h3 id=\"310-interpolated-kneser-ney-\u5e73\u6ed1\">&nbsp;Interpolated Kneser-Ney \u5e73\u6ed1<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#310-interpolated-kneser-ney-%E5%B9%B3%E6%BB%91\"><\/a><\/h3>\n\n\n\n<p>\u57fa\u4e8e Interpolation\uff0c\u6211\u4eec\u5f97\u5230\u4e86 Kneser-Ney \u7684\u6700\u540e\u4e00\u79cd\u7248\u672c\uff1a<strong>Interpolated Kneser-Ney \u5e73\u6ed1<\/strong>\u3002<\/p>\n\n\n\n<p><strong>Interpolation \u66ff\u4ee3 back-off<\/strong>\uff1a<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-30.png\" alt=\"\" class=\"wp-image-18631\" width=\"462\" height=\"75\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-30.png 640w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-30-300x49.png 300w\" sizes=\"(max-width: 462px) 100vw, 462px\" \/><\/figure><\/div>\n\n\n\n<p>\u8fd9\u91cc\uff0c\u6211\u4eec\u6240\u505a\u7684\u552f\u4e00\u6539\u53d8\u5c31\u662f\uff1a\u5c06\u4e4b\u524d\u89c2\u6d4b n-grams \u548c\u672a\u77e5 n-grams \u4e24\u79cd\u60c5\u51b5\u52a0\u5728\u4e00\u8d77\uff0c\u53d6\u4ee3\u4e86\u4e4b\u524d\u7684 back-off \u64cd\u4f5c\u3002\u6240\u4ee5\uff0c\u76f8\u6bd4\u4e4b\u524d\u4e8c\u9009\u4e00\u7684\u60c5\u51b5\uff0c\u73b0\u5728\u6211\u4eec\u90fd\u5408\u5e76\u5728\u4e00\u4e2a\u516c\u5f0f\u91cc\u3002<\/p>\n\n\n\n<p>\u53e6\u5916\uff0c\u76f8\u6bd4\u4e4b\u524d\u7684\u56fa\u5b9a\u6982\u7387\u8d28\u91cf&nbsp;\u03b1(wi\u22121)\uff0c\u8fd9\u91cc\u6211\u4eec\u66ff\u6362\u4e3a\u5f52\u4e00\u5316\u5e38\u6570&nbsp;\u03b2(wi\u22121)\uff0c\u4ee5\u786e\u4fdd\u4e0a\u4e0b\u6587&nbsp;wi\u22121&nbsp;\u5bf9\u5e94\u7684\u6240\u6709\u53ef\u80fd\u7684&nbsp;wi&nbsp;\u7684\u6982\u7387&nbsp;PIKN(wi\u2223wi\u22121)&nbsp;\u4e4b\u548c\u4e3a 1\u3002<\/p>\n\n\n\n<p>\u8fd9\u5c31\u662f\u6211\u4eec\u5230\u76ee\u524d\u4e3a\u6b62\u4ecb\u7ecd\u8fc7\u7684\u6700\u6709\u6548\u7684\u5e73\u6ed1\u65b9\u5f0f\uff0c\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\u6709\u5f88\u591a n-gram \u8bed\u8a00\u6a21\u578b\u90fd\u662f\u57fa\u4e8e Interpolated Kneser-Ney \u5e73\u6ed1\u5b9e\u73b0\u7684\u3002<\/p>\n\n\n\n<h3 id=\"311-\u5b9e\u8df5\u5e94\u7528\">\u5b9e\u8df5\u5e94\u7528<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#311-%E5%AE%9E%E8%B7%B5%E5%BA%94%E7%94%A8\"><\/a><\/h3>\n\n\n\n<ul><li>\u5728\u5b9e\u8df5\u4e2d\uff0c\u6211\u4eec\u901a\u5e38\u91c7\u7528 Kneser-Ney \u8bed\u8a00\u6a21\u578b\u5e76\u5c06 5-grams \u4f5c\u4e3a\u6700\u9ad8\u9636\u6570\u3002<\/li><li>\u5bf9\u4e8e\u6bcf\u4e2a n-gram \u9636\u6570\u90fd\u6709\u4e0d\u540c\u7684 discount \u503c\u3002<\/li><li>\u5f53\u6211\u4eec\u8bd5\u56fe\u5b66\u4e60\u5982\u4f55\u5728\u5b83\u4eec\u4e4b\u95f4\u8fdb\u884c Interpolation \u65f6\uff0c\u6211\u4eec\u5c06\u4ece\u6570\u636e\u4e2d\u5b66\u4e60\u3002<\/li><\/ul>\n\n\n\n<h2 id=\"4-\u751f\u6210\u8bed\u8a00\">\u751f\u6210\u8bed\u8a00<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#4-%E7%94%9F%E6%88%90%E8%AF%AD%E8%A8%80\"><\/a><\/h2>\n\n\n\n<p>\u5728\u6700\u540e\u4e00\u90e8\u5206\u4e2d\uff0c\u6211\u4eec\u5c06\u4ecb\u7ecd\u5982\u4f55\u5229\u7528\u8bed\u8a00\u6a21\u578b\u6765\u00a0<strong>\u751f\u6210\u8bed\u8a00\uff08Generating Language\uff09<\/strong>\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u8fd9\u91cc\u8ba8\u8bba\u7684\u662f\u5229\u7528\u8bed\u8a00\u6a21\u578b\u751f\u6210\u8bed\u8a00\u7684\u4e00\u79cd\u901a\u7528\u7684\u65b9\u6cd5\uff0c\u5e76\u4e0d\u4ec5\u4ec5\u5c40\u9650\u4e8e n-gram \u8bed\u8a00\u6a21\u578b\u3002<\/p>\n\n\n\n<p>\u4f46\u662f\u6211\u4eec\u8fd8\u662f\u4f1a\u4ee5 n-gram \u8bed\u8a00\u6a21\u578b\u4f5c\u4e3a\u4f8b\u5b50\uff1a<\/p>\n\n\n\n<ul><li>\u7ed9\u5b9a\u4e00\u4e2a\u521d\u59cb\u5355\u8bcd\uff0c\u4ece\u8bed\u8a00\u6a21\u578b\u5b9a\u4e49\u7684\u6982\u7387\u5206\u5e03\u4e2d\u62bd\u53d6\u4e00\u4e2a\u8bcd\u4f5c\u4e3a\u4e0b\u4e00\u4e2a\u51fa\u73b0\u7684\u5355\u8bcd\u3002<\/li><li>\u5728\u6211\u4eec\u7684 n-gram \u8bed\u8a00\u6a21\u578b\u4e2d\u5305\u542b&nbsp;(n\u22121)&nbsp;\u4e2a\u8d77\u59cb tokens\uff0c\u7528\u4e8e\u63d0\u4f9b\u751f\u6210\u7b2c\u4e00\u4e2a\u5355\u8bcd\u6240\u9700\u7684\u4e0a\u4e0b\u6587\u3002<ul><li>\u6c38\u8fdc\u4e0d\u4f1a\u751f\u6210\u8d77\u59cb\u6807\u8bb0&nbsp;&lt;s&gt;\uff0c\u5b83\u53ea\u4f5c\u4e3a\u521d\u59cb\u5355\u8bcd\u7684\u751f\u6210\u6761\u4ef6<\/li><li>\u751f\u6210&nbsp;&lt;\/s&gt;&nbsp;\u6765\u7ed3\u675f\u4e00\u4e2a\u5e8f\u5217<\/li><\/ul><\/li><\/ul>\n\n\n\n<p><strong>\u4f8b\u5b50\uff1aBigram \u8bed\u8a00\u6a21\u578b<\/strong><\/p>\n\n\n\n<ul><li>&nbsp;Sentence&nbsp;=&lt;s&gt;<\/li><li>&nbsp;P(?\u2223&lt;s&gt;)=\u201ca\u201d<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/andy-blog.oss-cn-beijing.aliyuncs.com\/blog\/2020-03-14-WX20200314-122151%402x.png\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u8fd9\u91cc\u662f\u4e00\u4e2a\u5f88\u7b80\u5355\u7684\u4f8b\u5b50\uff0c\u6211\u4eec\u6709\u4e00\u4e2a bigram \u8bed\u8a00\u6a21\u578b\u3002\u73b0\u5728\u6709\u4e00\u4e2a\u7a7a\u53e5\u5b50\uff0c\u5373\u53ea\u5305\u542b\u4e00\u4e2a\u8d77\u59cb\u6807\u8bb0&nbsp;&lt;s&gt;\u3002\u6211\u4eec\u8bd5\u56fe\u9884\u6d4b\u5728\u7ed9\u5b9a\u4e00\u4e2a\u8d77\u59cb\u6807\u8bb0&nbsp;&lt;s&gt;&nbsp;\u7684\u6761\u4ef6\u4e0b\uff0c\u4e0b\u4e00\u4e2a\u6700\u6709\u53ef\u80fd\u51fa\u73b0\u7684\u5355\u8bcd\u662f\u4ec0\u4e48\u3002\u6240\u4ee5\uff0c\u6211\u4eec\u4f1a\u5229\u7528 bigram \u8bed\u8a00\u6a21\u578b\u6765\u9010\u4e2a\u68c0\u67e5\u8bcd\u6c47\u8868\u4e2d\u6bcf\u4e2a\u5355\u8bcd&nbsp;w&nbsp;\u7684\u6761\u4ef6\u6982\u7387&nbsp;P(w\u2223&lt;s&gt;)\uff0c\u5e76\u9009\u62e9\u5176\u4e2d\u6982\u7387\u6700\u5927\u7684\u90a3\u4e2a\u5355\u8bcd\u4f5c\u4e3a\u6211\u4eec\u7684\u9884\u6d4b\u7ed3\u679c\u3002\u8fd9\u91cc\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u5230\u5355\u8bcd \u201ca\u201d \u51fa\u73b0\u5728\u4e00\u4e2a\u53e5\u5b50\u5f00\u5934\u7684\u6982\u7387\u6700\u5927\uff0c\u6211\u4eec\u5c06\u5b83\u6dfb\u52a0\u5230\u53e5\u5b50\u4e2d\u3002<\/p>\n\n\n\n<ul><li>&nbsp;Sentence&nbsp;=&lt;s&gt;&nbsp;a<\/li><li>&nbsp;P(?\u2223a)=\u201ccow\u201d<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/andy-blog.oss-cn-beijing.aliyuncs.com\/blog\/2020-03-14-WX20200314-122224%402x.png\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u73b0\u5728\u6211\u4eec\u7684\u53e5\u5b50\u6709\u4e86\u7b2c\u4e00\u4e2a\u5355\u8bcd \u201ca\u201d\uff0c\u6211\u4eec\u60f3\u77e5\u9053\u4e0b\u4e00\u4e2a\u6700\u6709\u53ef\u80fd\u51fa\u73b0\u7684\u5355\u8bcd\u662f\u4ec0\u4e48\u3002\u8fd8\u662f\u548c\u4e4b\u524d\u4e00\u6837\uff0c\u6211\u4eec\u9010\u4e00\u68c0\u67e5\u8bcd\u6c47\u8868\u4e2d\u5404\u4e2a\u8bcd\u5728\u7ed9\u5b9a\u4e0a\u4e0b\u6587\u5355\u8bcd \u201ca\u201d \u7684\u60c5\u51b5\u4e0b\uff0c\u54ea\u4e2a\u8bcd\u5bf9\u5e94\u7684\u6761\u4ef6\u6982\u7387\u6700\u5927\u3002\u53ef\u4ee5\u770b\u5230\uff0c\u8fd9\u91cc\u5355\u8bcd \u201ccow\u201d \u51fa\u73b0\u5728\u5355\u8bcd \u201ca\u201d \u4e4b\u540e\u7684\u6982\u7387\u6700\u5927\uff0c\u6240\u4ee5\u6211\u4eec\u5c06\u5b83\u6dfb\u52a0\u5230\u53e5\u5b50\u4e2d\u3002<\/p>\n\n\n\n<ul><li>&nbsp;Sentence&nbsp;=&lt;s&gt;&nbsp;a cow<\/li><li>&nbsp;P(?\u2223cow)=\u201ceats\u201d<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/andy-blog.oss-cn-beijing.aliyuncs.com\/blog\/2020-03-14-WX20200314-122246%402x.png\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u91cd\u590d\u4e0a\u9762\u7684\u6b65\u9aa4\uff0c\u6211\u4eec\u5f97\u5230\u4e86\u4e0b\u4e00\u4e2a\u6700\u6709\u53ef\u80fd\u7684\u5355\u8bcd \u201ceats\u201d \u5e76\u5c06\u5b83\u6dfb\u52a0\u5230\u53e5\u5b50\u4e2d\u3002<\/p>\n\n\n\n<ul><li>&nbsp;Sentence&nbsp;=&lt;s&gt;&nbsp;a cow eats<\/li><li>&nbsp;P(?\u2223eats)=\u201cgrass\u201d<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/andy-blog.oss-cn-beijing.aliyuncs.com\/blog\/2020-03-14-WX20200314-122315%402x.png\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u7ee7\u7eed\uff0c\u6211\u4eec\u5f97\u5230\u5355\u8bcd \u201cgrass\u201d \u5e76\u5c06\u5b83\u6dfb\u52a0\u5230\u53e5\u5b50\u4e2d\u3002<\/p>\n\n\n\n<ul><li>&nbsp;Sentence&nbsp;=&lt;s&gt;&nbsp;a cow eats grass<\/li><li>&nbsp;P(?\u2223grass)=\u201c&lt;\/s&gt;\u201d<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/andy-blog.oss-cn-beijing.aliyuncs.com\/blog\/2020-03-14-WX20200314-122334%402x.png\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u6700\u7ec8\uff0c\u6211\u4eec\u9884\u6d4b\u5355\u8bcd \u201cgrass\u201d \u540e\u9762\u6700\u6709\u53ef\u80fd\u51fa\u73b0\u7684\u662f\u7ed3\u675f\u6807\u8bb0 \u201c&lt;\/s&gt;\u201d\uff0c\u6211\u4eec\u5c06\u5b83\u6dfb\u52a0\u5230\u53e5\u5b50\u4e2d\u3002<\/p>\n\n\n\n<ul><li>&nbsp;Sentence&nbsp;=&lt;s&gt;&nbsp;a cow eats grass&nbsp;&lt;\/s&gt;<\/li><li>\u5b8c\u6210<\/li><\/ul>\n\n\n\n<p>\u73b0\u5728\u6211\u4eec\u5f97\u5230\u4e86\u4e00\u4e2a\u7531\u8fd9\u4e2a bigram \u8bed\u8a00\u6a21\u578b\u751f\u6210\u7684\u53e5\u5b50\uff1aa cow eats grass<\/p>\n\n\n\n<h3 id=\"42-\u5982\u4f55\u9009\u62e9\u4e0b\u4e00\u4e2a\u5355\u8bcd\">\u5982\u4f55\u9009\u62e9\u4e0b\u4e00\u4e2a\u5355\u8bcd<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#42-%E5%A6%82%E4%BD%95%E9%80%89%E6%8B%A9%E4%B8%8B%E4%B8%80%E4%B8%AA%E5%8D%95%E8%AF%8D\"><\/a><\/h3>\n\n\n\n<ul><li><strong>Argmax<\/strong>\uff1a\u5728\u6bcf\u4e00\u8f6e\u4e2d\u9009\u62e9\u4e0e\u4e0a\u4e0b\u6587\u5171\u73b0\u6982\u7387\u6700\u9ad8\u7684\u90a3\u4e2a\u5355\u8bcd\u3002<ul><li><strong>\u8d2a\u5a6a\u641c\u7d22\uff08Greedy search \uff09<\/strong><br>\u8fd9\u5176\u5b9e\u662f\u4e00\u79cd\u8d2a\u5a6a\u641c\u7d22\u7b56\u7565\uff0c\u56e0\u4e3a\u5373\u4f7f\u5728\u6bcf\u4e00\u6b65\u4e2d\u6211\u4eec\u90fd\u9009\u62e9\u6982\u7387\u6700\u9ad8\u7684\u90a3\u4e2a\u5355\u8bcd\uff0c\u4e5f\u65e0\u6cd5\u4fdd\u8bc1\u6700\u7ec8\u751f\u6210\u7684\u53e5\u5b50\u5177\u6709\u6700\u4f18\u7684\u6982\u7387\u3002<\/li><\/ul><\/li><li><strong>Beam search decoding<\/strong><br>\u4e00\u79cd\u66f4\u597d\u7684\u65b9\u6cd5\u662f Beam search decoding\uff0c\u5b83\u5728\u673a\u5668\u7ffb\u8bd1\u4e2d\u5e94\u7528\u975e\u5e38\u5e7f\u6cdb\u3002<ul><li>\u5728\u6bcf\u8f6e\u4e2d\uff0c\u6211\u4eec\u8ddf\u8e2a\u6982\u7387\u6700\u9ad8\u7684\u524d&nbsp;N&nbsp;\u4e2a\u5355\u8bcd<\/li><li>\u6211\u4eec\u603b\u662f\u68c0\u67e5\u8fd9\u51e0\u4e2a\u5019\u9009\u5355\u8bcd\u7ed9\u51fa\u7684\u5b8c\u6574\u53e5\u5b50\u7684\u6982\u7387<\/li><li>\u8fd9\u79cd\u65b9\u6cd5\u53ef\u4ee5\u751f\u6210\u5177\u6709&nbsp;<strong>\u8fd1\u4f3c\u6700\u4f18\uff08near-optimal\uff09<\/strong>&nbsp;\u6982\u7387\u7684\u53e5\u5b50<\/li><\/ul><\/li><li><strong>\u4ece\u5206\u5e03\u4e2d\u968f\u673a\u62bd\u6837<\/strong><br>\u53e6\u4e00\u79cd\u65b9\u6cd5\u662f\u4ece\u8bed\u8a00\u6a21\u578b\u7ed9\u51fa\u7684\u6982\u7387\u5206\u5e03\u4e2d\u968f\u673a\u62bd\u6837\uff0c\u4f8b\u5982\uff1atemperature sampling<\/li><\/ul>\n\n\n\n<h2>\u8bc4\u4f30\u8bed\u8a00\u6a21\u578b<\/h2>\n\n\n\n<p>\u5982\u4f55\u8bc4\u4f30\u4e00\u4e2a\u8bed\u8a00\u6a21\u578b\u7684\u8d28\u91cf\uff1f<\/p>\n\n\n\n<h3 id=\"51-\u8bc4\u4f30\">\u8bc4\u4f30<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#51-%E8%AF%84%E4%BC%B0\"><\/a><\/h3>\n\n\n\n<p>\u8bed\u8a00\u6a21\u578b\u7684\u8bc4\u4f30\u901a\u5e38\u6709\u4e24\u79cd\u8303\u5f0f\uff1a<\/p>\n\n\n\n<ul><li><strong>\u5916\u90e8\u7684\uff08Extrinsic\uff09<\/strong><br>\u8fd9\u79cd\u8bc4\u4f30\u8303\u5f0f\u5e38\u89c1\u4e8e\u4e0b\u6e38\u5e94\u7528\u4e2d\uff0c\u6211\u4eec\u6839\u636e\u5176\u53cd\u9988\u6765\u8bc4\u4f30\u8bed\u8a00\u6a21\u578b\u7684\u8868\u73b0\u3002\u6bd4\u5982\u5bf9\u4e8e\u673a\u5668\u7ffb\u8bd1\u4e2d\u7684\u67d0\u4e9b\u4efb\u52a1\uff0c\u6211\u4eec\u53ef\u4ee5\u6bd4\u8f83\u4e0d\u540c\u8bed\u8a00\u6a21\u578b\u5728\u5b8c\u6210\u8be5\u4efb\u52a1\u4e0a\u7684\u8868\u73b0\u3002<ul><li>\u4f8b\u5982\uff1a\u62fc\u5199\u7ea0\u9519\u3001\u673a\u5668\u7ffb\u8bd1<\/li><\/ul><\/li><li><strong>\u5185\u90e8\u7684\uff08Intrinsic\uff09<\/strong><br>\u5728\u8fd9\u79cd\u8bc4\u4f30\u8303\u5f0f\u4e0b\uff0c\u6211\u4eec\u4e0d\u4f9d\u8d56\u4efb\u4f55\u4e0b\u6e38\u5e94\u7528\uff0c\u800c\u662f\u89c2\u5bdf\u6211\u4eec\u7684\u8bed\u8a00\u6a21\u578b\u5728\u4fdd\u7559\u6d4b\u8bd5\u96c6\u4e0a\u7684&nbsp;<strong>Perplexity<\/strong>\u3002<ul><li>\u5728\u4fdd\u7559\u6d4b\u8bd5\u96c6\uff08held-out test set\uff09\u4e0a\u7684 Perplexity<\/li><li><strong>Perplexity\uff08\u56f0\u60d1\uff09<\/strong>&nbsp;\u8861\u91cf\u7684\u662f\u6211\u4eec\u5bf9\u4e8e\u6a21\u578b\u5728\u6d4b\u8bd5\u6570\u636e\u4e0a\u7ed9\u51fa\u7684\u9884\u6d4b\u7684\u7f6e\u4fe1\u5ea6\u3002\u7f6e\u4fe1\u5ea6\u8d8a\u9ad8\uff0c\u5bf9\u5e94\u7684 Perplexity \u5c31\u8d8a\u4f4e\uff0c\u4ee3\u8868\u6211\u4eec\u7684\u6a21\u578b\u8d8a\u597d\u3002<\/li><\/ul><\/li><\/ul>\n\n\n\n<h3 id=\"52-perplexity\">&nbsp;Perplexity<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#52-perplexity\"><\/a><\/h3>\n\n\n\n<ul><li>\u6574\u4e2a\u6d4b\u8bd5\u96c6\u7684\u9006\u6982\u7387\uff08Inverse probability\uff09<ul><li>\u901a\u8fc7\u5355\u8bcd tokens\uff08\u5305\u62ec\u7ed3\u675f\u6807\u8bb0&nbsp;&lt;\/s&gt;\uff09\u7684\u6570\u91cf\u5b9e\u73b0\u5f52\u4e00\u5316\uff08Normalization\uff09<\/li><\/ul><\/li><li>\u5047\u8bbe\u6211\u4eec\u4fdd\u7559\u7684\u6d4b\u8bd5\u96c6\u8bed\u6599\u5e93\u662f\u4e00\u4e2a\u7531&nbsp;m&nbsp;\u4e2a\u5355\u8bcd&nbsp;w1,w2,\u2026,wm&nbsp;\u7ec4\u6210\u7684\u5e8f\u5217\uff0c\u6211\u4eec\u7528&nbsp;PP&nbsp;\u8868\u793a Perplexity\u3002\u4ece\u4e0b\u9762\u7684\u516c\u5f0f\u53ef\u4ee5\u770b\u5230\uff0c\u5b83\u662f\u901a\u8fc7\u5bf9\u6574\u4e2a\u6d4b\u8bd5\u96c6\u7684\u6982\u7387&nbsp;P(w1,w2,\u2026,wm)&nbsp;\u53d6\u5012\u6570\uff0c\u7136\u540e\u518d\u5f00&nbsp;m&nbsp;\u6b21\u65b9\u5f97\u5230\u7684\uff1a<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" width=\"564\" height=\"162\" src=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-31.png\" alt=\"\" class=\"wp-image-18638\" srcset=\"http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-31.png 564w, http:\/\/139.9.1.231\/wp-content\/uploads\/2024\/09\/image-31-300x86.png 300w\" sizes=\"(max-width: 564px) 100vw, 564px\" \/><\/figure>\n\n\n\n<ul><li>\u5982\u679c\u6211\u4eec\u9047\u5230\u672a\u77e5\u5355\u8bcd\uff08OOV\uff09\uff0c\u6211\u4eec\u901a\u5e38\u662f\u76f4\u63a5\u5ffd\u7565\u6389\uff0c\u56e0\u4e3a\u6211\u4eec\u6ca1\u6709\u529e\u6cd5\u8868\u793a\u5b83\u4eec\u3002<\/li><li><strong>Perplexity \u8d8a\u4f4e\uff0c\u6a21\u578b\u8868\u73b0\u8d8a\u597d\u3002<\/strong><br>\u5047\u5982\u6211\u4eec\u6a21\u578b\u7684 Perplexity \u53ea\u6709&nbsp;1\uff0c\u90a3\u4e48\u8fd9\u662f\u6700\u597d\u7684\u60c5\u51b5\u3002\u56e0\u4e3a\u5f53\u6211\u4eec\u7684\u6d4b\u8bd5\u96c6\u8bed\u6599\u5e93\u4e0a\u7684\u6982\u7387&nbsp;P(w1,w2,\u2026,wm)=1&nbsp;\u65f6\uff0cPP(w1,w2,\u2026,wm)=1\u3002\u800c\u5bf9\u4e8e\u4e00\u4e2a\u975e\u5e38\u5dee\u7684\u8bed\u8a00\u6a21\u578b\uff0c\u53ef\u80fd\u5728\u6d4b\u8bd5\u96c6\u4e0a\u7684\u6982\u7387&nbsp;P(w1,w2,\u2026,wm)=0\uff0c\u6b64\u65f6\u6a21\u578b\u7684 Perplexity \u5c06\u8d8b\u8fd1&nbsp;\u221e\u3002\u6240\u4ee5\uff0c\u6700\u7406\u60f3\u7684\u60c5\u51b5\u662f Perplexity \u7b49\u4e8e&nbsp;1\uff0c\u5f53\u7136\uff0c\u6211\u4eec\u6c38\u8fdc\u4e0d\u53ef\u80fd\u8fbe\u5230\u8fd9\u4e2a\u503c\u3002<\/li><\/ul>\n\n\n\n<h2 id=\"6-\u603b\u7ed3\">\u603b\u7ed3<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#6-%E6%80%BB%E7%BB%93\"><\/a><\/h2>\n\n\n\n<ul><li>N-gram \u6a21\u578b\u5728\u6355\u6349\u8bed\u8a00\u7684\u53ef\u9884\u6d4b\u6027\u65b9\u9762\u662f\u4e00\u79cd\u7b80\u5355\u4e14\u9ad8\u6548\u7684\u65b9\u6cd5\u3002<br>\u6a21\u578b\u7684\u6784\u5efa\u5f88\u5bb9\u6613\uff1a\u6211\u4eec\u53ea\u9700\u8981\u4e00\u4e2a\u5927\u7684\u8bed\u6599\u5e93\uff0c\u5e76\u4e14\u5bf9\u5355\u8bcd\u548c\u4e0a\u4e0b\u6587\u8fdb\u884c\u8ba1\u6570\u5373\u53ef\u3002<\/li><li>\u4fe1\u606f\u53ef\u4ee5\u901a\u8fc7\u65e0\u76d1\u7763\u7684\u65b9\u5f0f\u63a8\u5bfc\u5f97\u51fa\uff0c\u53ef\u4ee5\u6269\u5c55\u5230\u5927\u578b\u8bed\u6599\u5e93\u3002<\/li><li>\u7531\u4e8e\u7a00\u758f\u6027\u7684\u5b58\u5728\uff0c\u9700\u8981\u8fdb\u884c\u5e73\u6ed1\u5904\u7406\u624d\u80fd\u4fdd\u8bc1\u6709\u6548\u6027\u3002<br>\u6211\u4eec\u9700\u8981\u4e00\u4e9b\u5de5\u7a0b\u4e0a\u7684\u6280\u5de7\u5904\u7406\u7a00\u758f\u6027\u95ee\u9898\uff0c\u4f8b\u5982\uff1asmoothing\u3001back-off\u3001interpolation \u7b49\u3002<\/li><\/ul>\n\n\n\n<p>\u867d\u7136 n-gram \u6a21\u578b\u975e\u5e38\u7b80\u5355\uff0c\u4f46\u662f\u5b83\u5728\u5b9e\u8df5\u4e2d\u7684\u6548\u679c\u975e\u5e38\u597d\u3002\u6240\u4ee5\uff0c\u5728\u6784\u5efa\u8bed\u8a00\u6a21\u578b\u65f6\uff0c\u6211\u4eec\u901a\u5e38\u4f1a\u9009\u62e9\u5c06 n-gram \u6a21\u578b\u4f5c\u4e3a baseline\uff0c\u5c3d\u7ba1\u76ee\u524d\u6709\u5f88\u591a\u6a21\u578b\u90fd\u91c7\u7528\u4e86\u6df1\u5ea6\u5b66\u4e60\u3002<\/p>\n\n\n\n<h2 id=\"7-\u601d\u8003\">\u601d\u8003<a href=\"https:\/\/yey.world\/2020\/03\/09\/COMP90042-03\/#7-%E6%80%9D%E8%80%83\"><\/a><\/h2>\n\n\n\n<p><strong>\u601d\u8003\uff1a<\/strong>&nbsp;Interpolation\u3001Interpolated Kneser-Ney \u548c Kneser-Ney \u4e4b\u95f4\u6709\u4ec0\u4e48\u533a\u522b\uff1f\u6211\u4eec\u5e94\u5f53\u5982\u4f55\u5224\u65ad\u5e94\u8be5\u91c7\u7528\u54ea\u79cd\u65b9\u6cd5\uff1f<\/p>\n\n\n\n<p>\u9996\u5148\uff0c\u6211\u4eec\u5e94\u8be5\u660e\u786e\u4e00\u70b9\uff1aInterpolated\uff08\u63d2\u503c\uff09\u3001Smoothing\uff08\u5e73\u6ed1\uff09\u548c Backoff\uff08\u56de\u9000\uff09\u90fd\u662f\u7528\u6765\u89e3\u51b3\u6570\u636e\u7a00\u758f\u95ee\u9898\uff08sparsity\uff09\u7684\u65b9\u6cd5\u3002\u6211\u4eec\u5728\u8fd9\u8282\u8bfe\u4e2d\u8ba8\u8bba\u7684\u524d 3 \u79cd\u5e73\u6ed1\u65b9\u6cd5\uff08\u62c9\u666e\u62c9\u65af\u3001\u201c\u52a0 k\u201d \u548c Lidstone\uff09\u90fd\u662f\u5728&nbsp;<strong>\u548c\u539f\u5148\u7684 N-gram \u6a21\u578b\u76f8\u540c\u7684\u9636\u6570<\/strong>&nbsp;\u5185\u91cd\u65b0\u5206\u914d\u6982\u7387\uff0c\u5c06\u6982\u7387\u8d28\u91cf\u4ece\u5e38\u89c1\u60c5\u51b5\u5411\u7f55\u89c1\u60c5\u51b5\u8fdb\u884c\u504f\u79fb\u3002<\/p>\n\n\n\n<p>Interpolation \u548c Backoff \u90fd\u662f\u901a\u8fc7&nbsp;<strong>\u7ed3\u5408\u4e0d\u540c\u9636\u6570\u7684 N-gram \u6a21\u578b<\/strong>&nbsp;\u6765\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u3002\u5bf9\u4e8e Backoff \u800c\u8a00\uff0c\u5982\u679c\u9ad8\u9636 higher-gram \u7684\u8ba1\u6570\u4e3a&nbsp;0\uff0c\u90a3\u4e48\u5b83\u5c06\u5b8c\u5168\u843d\u56de\u4f4e\u9636 lower-gram\uff1b\u800c Interpolation \u5219\u662f\u901a\u8fc7\u5c06\u6211\u4eec\u6240\u6709\u7684 N-gram \u6a21\u578b\u52a0\u6743\u6c42\u548c\u6765\u5c06\u5b83\u4eec\u7ed3\u5408\u8d77\u6765\u3002<\/p>\n\n\n\n<p>\u73b0\u5728\uff0c\u5f53\u6211\u4eec\u91c7\u7528\u4f4e\u9636\u6a21\u578b\u65f6\u53c8\u4f1a\u5e26\u6765\u4e00\u4e2a\u65b0\u7684\u95ee\u9898\u3002\u4f8b\u5982\uff0c\u5bf9\u4e8e\u5355\u8bcd \u201cOld\u201d \u548c \u201cZealand\u201d\uff0c\u5f88\u53ef\u80fd\u5b83\u4eec\u7684 bi-gram \u201cOld Zealand\u201d \u8ba1\u6570\u4e3a&nbsp;0\uff0c\u6240\u4ee5\u6211\u4eec\u9700\u8981\u4f9d\u8d56 unigram \u6a21\u578b\u63d0\u4f9b\u7684\u6982\u7387\u3002\u60f3\u8c61\u4e00\u4e0b\uff0c\u5982\u679c\u5355\u8bcd \u201cZealand\u201d \u5177\u6709\u4e00\u4e2a\u975e\u5e38\u9ad8\u7684 unigram \u6982\u7387\uff0c\u90a3\u4e48\u5bf9\u4e8e\u8fd9\u4e24\u4e2a\u8bcd\u7684 bi-gram\uff0c\u6211\u4eec\u8fd8\u662f\u53ef\u4ee5\u5f97\u5230\u4e00\u4e2a\u76f8\u5bf9\u8f83\u9ad8\u7684\u5171\u73b0\u6982\u7387\uff0c\u800c\u8fd9\u4e0d\u662f\u6211\u4eec\u5e0c\u671b\u770b\u5230\u7684\u3002<\/p>\n\n\n\n<p>Kneser-Ney Smoothing \u4e2d\u5f15\u5165\u4e86\u6240\u8c13&nbsp;<strong>\u5ef6\u7eed\u8ba1\u6570\uff08continuation count\uff09<\/strong>&nbsp;\u7684\u6982\u5ff5\u3002\u56e0\u4e3a\u5728\u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u5355\u8bcd \u201cZealand\u201d \u53ea\u51fa\u73b0\u5728\u4e0a\u4e0b\u6587\u5355\u8bcd \u201cNew\u201d \u7684\u540e\u9762\uff0c\u6240\u4ee5\u5bf9\u4e8e\u5355\u8bcd \u201cZealand\u201d \u51fa\u73b0\u5728\u4e0a\u4e0b\u6587\u5355\u8bcd \u201cOld\u201d \u540e\u9762\u8fd9\u79cd\u60c5\u51b5\uff08\u5373 bi-gram \u201cOld Zealand\u201d\uff09\u7684\u5ef6\u7eed\u8ba1\u6570\u4f1a\u975e\u5e38\u4f4e\u3002\u5230\u8fd9\u91cc\uff0c\u6211\u4eec\u901a\u8fc7&nbsp;<strong>\u5728\u4e0d\u540c\u4e0a\u4e0b\u6587\u4e2d\u7684\u9891\u7387\u8ba1\u6570<\/strong>&nbsp;\u89e3\u51b3\u4e86\u4e0a\u8ff0\u4f8b\u5b50\u4e2d\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n<p>\u56de\u5230\u539f\u95ee\u9898\u4e2d\u63d0\u5230\u7684\u54ea\u79cd\u65b9\u6cd5\u66f4\u597d\uff0c\u6211\u4eec\u53ef\u4ee5\u5728 Backoff \u6216\u8005 Interpolation \u4e8c\u8005\u4e2d\u9009\u62e9\u4e00\u79cd\u6765\u4f7f\u7528 Kneser-Ney Smoothing\u3002\u901a\u5e38\u6765\u8bf4\uff0cInterpolation \u53ef\u80fd\u66f4\u5408\u9002\uff0c\u56e0\u4e3a\u8fd9\u79cd\u65b9\u5f0f\u66f4\u7075\u6d3b\uff08\u56e0\u4e3a\u6211\u4eec\u8003\u8651\u4e86\u6240\u6709\u9636\u6570\u7684 N-gram \u6a21\u578b\uff09\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6700\u8fd1\u5728\u505aASR\u8bed\u97f3\u8bc6\u522b\u4efb\u52a1\uff0c\u57fa\u4e8e\u963f\u91ccFunASR\u6846\u67b6\uff0c\u7279\u6b64\u8bb0\u5f55\u4e0b\u8ddf\u8bed\u8a00\u6a21\u578b\uff08LM\uff09\u76f8\u5173\u77e5\u8bc6\u3002 \u8bed\u8a00\u6a21\u578b\u89e3\u7801 \u4f20 &hellip; <a href=\"http:\/\/139.9.1.231\/index.php\/2024\/09\/10\/asr-n-gram\/\" class=\"more-link\">\u7ee7\u7eed\u9605\u8bfb<span class=\"screen-reader-text\">ASR\u8bed\u97f3\u8bc6\u522b&#8212;N-gram \u8bed\u8a00\u6a21\u578b<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[4,38,34],"tags":[],"_links":{"self":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/18401"}],"collection":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/comments?post=18401"}],"version-history":[{"count":92,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/18401\/revisions"}],"predecessor-version":[{"id":26418,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/18401\/revisions\/26418"}],"wp:attachment":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/media?parent=18401"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/categories?post=18401"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/tags?post=18401"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}