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<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/622b80ca3d2fbb000784b88b/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">隐马尔科夫模型和词性标注</div><div class="t m0 x2 h3 y2 ff1 fs1 fc1 sc0 ls0 ws0">刘挺</div><div class="t m0 x3 h3 y3 ff1 fs1 fc1 sc0 ls0 ws0">哈工大信息检索研究室</div><div class="t m0 x4 h4 y4 ff2 fs1 fc1 sc0 ls1 ws0">2004<span class="ff1 ls0">年春</span></div></div><div class="pi" data-data='{"ctm":[0.000000,-1.140143,1.140143,0.000000,0.000000,678.384798]}'></div></div>
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<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/622b80ca3d2fbb000784b88b/bg2.jpg"><div class="t m0 x5 h2 y5 ff1 fs0 fc0 sc0 ls0 ws0">大纲</div><div class="t m0 x6 h4 y6 ff2 fs1 fc1 sc0 ls0 ws0">•<span class="_ _0"> </span><span class="ff1">隐马尔科夫模型</span></div><div class="t m0 x7 h5 y7 ff2 fs2 fc1 sc0 ls0 ws0">–<span class="_ _1"> </span><span class="ff1 ls2">隐马尔科夫模型概述</span></div><div class="t m0 x7 h6 y8 ff3 fs2 fc1 sc0 ls0 ws0">–<span class="_ _2"> </span><span class="ff1">任务<span class="ff2">1</span><span class="ls3">：计算观察序列的概率</span></span></div><div class="t m0 x7 h6 y9 ff3 fs2 fc1 sc0 ls0 ws0">–<span class="_ _2"> </span><span class="ff1">任务<span class="ff2">2</span><span class="ls4">：计算能够解释观察序列的最大可能</span></span></div><div class="t m0 x8 h7 ya ff1 fs2 fc1 sc0 ls2 ws0">的状态序列</div><div class="t m0 x7 h6 yb ff3 fs2 fc1 sc0 ls0 ws0">–<span class="_ _2"> </span><span class="ff1">任务<span class="ff2">3</span><span class="ls2">：根据观察序列寻找最佳参数模型</span></span></div><div class="t m0 x6 h4 yc ff2 fs1 fc1 sc0 ls0 ws0">•<span class="_ _0"> </span><span class="ff1">词性标注</span></div></div><div class="pi" data-data='{"ctm":[0.000000,-1.140143,1.140143,0.000000,0.000000,678.384798]}'></div></div>
<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/622b80ca3d2fbb000784b88b/bg3.jpg"><div class="t m0 x9 h2 y1 ff1 fs0 fc0 sc1 ls0 ws0">隐马尔科夫模型概述</div></div><div class="pi" data-data='{"ctm":[0.000000,-1.140143,1.140143,0.000000,0.000000,678.384798]}'></div></div>
<div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/622b80ca3d2fbb000784b88b/bg4.jpg"><div class="t m0 xa h2 y5 ff1 fs0 fc0 sc1 ls0 ws0">马尔科夫链</div><div class="t m0 x6 h8 yd ff3 fs1 fc1 sc0 ls0 ws0">•<span class="_ _3"> </span><span class="ff1">状态序列<span class="ff2 ls5 ws1">: X</span></span></div><div class="t m0 xb h9 ye ff2 fs3 fc1 sc0 ls0 ws0">1</div><div class="t m0 xc h4 yd ff2 fs1 fc1 sc0 ls6 ws2">, X</div><div class="t m0 xd h9 ye ff2 fs3 fc1 sc0 ls0 ws0">2</div><div class="t m0 xe h4 yd ff2 fs1 fc1 sc0 ls6 ws2">, X</div><div class="t m0 xf h9 ye ff2 fs3 fc1 sc0 ls0 ws0">3</div><div class="t m0 x10 h8 yd ff2 fs1 fc1 sc0 ls6 ws0">, <span class="ff3 ls0">…</span></div><div class="t m0 x7 h6 yf ff3 fs2 fc1 sc0 ls0 ws0">–<span class="_ _2"> </span><span class="ff1 ls2">常常是</span>“<span class="ff1">时序</span>”<span class="ff1">的</span></div><div class="t m0 x6 h8 y10 ff3 fs1 fc1 sc0 ls0 ws0">•<span class="_ _3"> </span><span class="ff1">从<span class="ff2">X</span></span></div><div class="t m0 x11 h9 y11 ff2 fs3 fc1 sc0 ls7 ws0">t-1</div><div class="t m0 x12 h4 y10 ff1 fs1 fc1 sc0 ls0 ws0">到<span class="ff2">X</span></div><div class="t m0 x13 h9 y11 ff2 fs3 fc1 sc0 ls0 ws0">t</div><div class="t m0 x14 h4 y10 ff1 fs1 fc1 sc0 ls1 ws0">的转换只依赖于<span class="ff2 ls0">X</span></div><div class="t m0 x15 h9 y11 ff2 fs3 fc1 sc0 ls7 ws0">t-1</div><div class="t m0 x16 ha y12 ff3 fs4 fc1 sc0 ls8 ws0">X2<span class="_ _4"> </span>X3<span class="_ _4"> </span>X4<span class="_ _5"></span>X1</div></div><div class="pi" data-data='{"ctm":[0.000000,-1.140143,1.140143,0.000000,0.000000,678.384798]}'></div></div>
<div id="pf5" class="pf w0 h0" data-page-no="5"><div class="pc pc5 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/622b80ca3d2fbb000784b88b/bg5.jpg"><div class="t m0 x17 hb y13 ff1 fs5 fc0 sc1 ls0 ws0">转移概率</div><div class="t m0 x18 hc y14 ff4 fs5 fc0 sc0 ls0 ws3">Transition Probabilities</div><div class="t m0 x19 h8 y15 ff3 fs1 fc1 sc0 ls0 ws0">•<span class="_ _3"> </span><span class="ff1">假设一个状态<span class="ff2">X</span></span></div><div class="t m0 x4 h9 y16 ff2 fs3 fc1 sc0 ls0 ws0">t</div><div class="t m0 x1a h4 y15 ff1 fs1 fc1 sc0 ls0 ws0">有<span class="ff2">N</span>个可能的值</div><div class="t m0 x1b h6 y17 ff3 fs2 fc1 sc0 ls0 ws0">–<span class="_ _2"> </span><span class="ff2">X</span></div><div class="t m0 x1c hd y18 ff2 fs6 fc1 sc0 ls0 ws0">t</div><div class="t m0 x1d h5 y17 ff2 fs2 fc1 sc0 ls9 ws0">=s</div><div class="t m0 x1e hd y18 ff2 fs6 fc1 sc0 ls0 ws0">1</div><div class="t m0 x1f h5 y17 ff2 fs2 fc1 sc0 lsa ws0">, X</div><div class="t m0 x20 hd y18 ff2 fs6 fc1 sc0 ls0 ws0">t</div><div class="t m0 x21 h5 y17 ff2 fs2 fc1 sc0 ls9 ws0">=s</div><div class="t m0 x22 hd y18 ff2 fs6 fc1 sc0 ls0 ws0">2</div><div class="t m0 x23 h6 y17 ff2 fs2 fc1 sc0 ls0 ws0">,<span class="ff3">…</span><span class="ws4">.., X</span></div><div class="t m0 xe hd y18 ff2 fs6 fc1 sc0 ls0 ws0">t</div><div class="t m0 x24 h5 y17 ff2 fs2 fc1 sc0 ls9 ws0">=s</div><div class="t m0 x25 hd y18 ff2 fs6 fc1 sc0 ls0 ws0">N</div><div class="t m0 x26 h5 y17 ff2 fs2 fc1 sc0 ls0 ws0">.</div><div class="t m0 x19 h8 y19 ff3 fs1 fc1 sc0 ls0 ws0">•<span class="_ _3"> </span><span class="ff1">转移概率的数量为：<span class="ff2">N</span></span></div><div class="t m0 x27 h9 y1a ff2 fs3 fc1 sc0 ls0 ws0">2</div><div class="t m0 x1b h6 y1b ff3 fs2 fc1 sc0 ls0 ws0">–<span class="_ _2"> </span><span class="ff2 lsb">P(X</span></div><div class="t m0 x28 hd y1c ff2 fs6 fc1 sc0 ls0 ws0">t</div><div class="t m0 x29 h5 y1b ff2 fs2 fc1 sc0 ls9 ws0">=s</div><div class="t m0 x2a hd y1c ff2 fs6 fc1 sc0 ls0 ws0">i</div><div class="t m0 x2b h5 y1b ff2 fs2 fc1 sc0 ls2 ws0">|X</div><div class="t m0 x2c hd y1c ff2 fs6 fc1 sc0 lsc ws0">t-1</div><div class="t m0 x2d h5 y1b ff2 fs2 fc1 sc0 lsd ws0">=s</div><div class="t m0 x2e hd y1c ff2 fs6 fc1 sc0 ls0 ws0">j</div><div class="t m0 x2f h5 y1b ff2 fs2 fc1 sc0 lse ws5">), 1<span class="ff1 ls0 ws0">≤<span class="_ _2"> </span></span><span class="lsf ws6">i, j <span class="ff1 ls0 ws0">≤<span class="ff2">N</span></span></span></div><div class="t m0 x19 h8 y1d ff3 fs1 fc1 sc0 ls0 ws0">•<span class="_ _3"> </span><span class="ff1">转移概率可以表示为<span class="ff2">N</span>×<span class="ff2">N</span>的矩阵或者有</span></div><div class="t m0 x30 h3 y1e ff1 fs1 fc1 sc0 ls0 ws0">向图</div></div><div class="pi" data-data='{"ctm":[0.000000,-1.140143,1.140143,0.000000,0.000000,678.384798]}'></div></div>
