資源簡介
Baum-Welch算法迭代估計隱馬爾科夫模型（HMM）的初始狀態概率分布以及其狀態轉移概率矩陣。其中mainfile_B_W.m為主函數，Baum_Welch.m為Baum-Welch算法迭代函數，Forward_variable.m與Backward_variable.m與Gamma_variable.m與Ksi_variable.m是需要計算的四種因子，B_pdf.m為混淆散射概率密度函數。
代碼片段和文件信息
function?beta?=?Backward_variable（LRR?A_Matrix?T?State_N）
????%?計算后向變量
????beta?=?zeros（T?State_N）;
????
????%?初始化
????for?i?=?1:State_N
????????beta（T?i）?=?1;
????end
????
????%?遞歸
????for?t?=?（T-1）:-1:1
????????for?i?=?1:State_N
????????????temp?=?0;
????????????for?j?=?1:State_N
????????????????temp?=?temp+A_Matrix（i?j）*B_pdf（LRR（t+1）?j）*beta（t+1?j）;
????????????end
????????????beta（t?i）?=?temp;
????????end
????????%?歸一化防止下溢出，其影響在之后gamma與ksi計算中會約去，從而不影響結果
????????beta（t?:）?=?beta（t?:）/sum（beta（t?:））;
????end
end
%?end?of?function
?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件????????615??2014-01-04?20:59??Baum_Welch?algorithm\Backward_variable.m
?????文件???????1293??2014-01-05?22:58??Baum_Welch?algorithm\Baum_Welch.m
?????文件????????426??2014-01-12?15:11??Baum_Welch?algorithm\B_pdf.m
?????文件????????553??2014-01-04?20:59??Baum_Welch?algorithm\Forward_variable.m
?????文件????????316??2014-01-04?20:59??Baum_Welch?algorithm\Gamma_variable.m
?????文件????????491??2014-01-04?21:00??Baum_Welch?algorithm\Ksi_variable.m
?????文件????????802??2014-01-12?15:15??Baum_Welch?algorithm\mainfile_B_W.m
?????目錄??????????0??2014-04-05?11:15??Baum_Welch?algorithm
-----------?---------??----------?-----??----
?????????????????4496????????????????????8
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