江西农业大学学报
江西農業大學學報
강서농업대학학보
ACTA AGRICULTURAE UNIVERSITATIS JIANGXIENSIS
2014年
5期
984-989
,共6页
吕丹%郑世跃%欧阳勋志%郭孝玉
呂丹%鄭世躍%歐暘勛誌%郭孝玉
려단%정세약%구양훈지%곽효옥
林木资源资产%批量评估%BP神经网络%敏感性分析
林木資源資產%批量評估%BP神經網絡%敏感性分析
림목자원자산%비량평고%BP신경망락%민감성분석
forest assets evaluation%mass appraisal%BP neural network%sensitivity analysis method
批量评估具有效率高、费用低且满足大量评估等优点。论文以中龄林为例,将BP神经网络应用于林木资源资产批量评估。通过比较学习算法、隐含层节点数,运用敏感性分析法确定影响因子对评估值的贡献程度,筛选输入层因子,从而优化了林木资源资产批量评估BP神经网络模型结构。结果表明:贝叶斯正则化法优于L-M算法;年龄、利率、蓄积、树种为强影响因子,这4个因子对评估值的贡献度超过60%;最优模型结构为BR 9-10-1,该模型平均绝对误差为32.46元/hm2,平均相对误差为1.28%,决定系数达0.9997,模型拟合精度高,泛化能力强,能够满足中龄林林木资源资产批量评估的要求。
批量評估具有效率高、費用低且滿足大量評估等優點。論文以中齡林為例,將BP神經網絡應用于林木資源資產批量評估。通過比較學習算法、隱含層節點數,運用敏感性分析法確定影響因子對評估值的貢獻程度,篩選輸入層因子,從而優化瞭林木資源資產批量評估BP神經網絡模型結構。結果錶明:貝葉斯正則化法優于L-M算法;年齡、利率、蓄積、樹種為彊影響因子,這4箇因子對評估值的貢獻度超過60%;最優模型結構為BR 9-10-1,該模型平均絕對誤差為32.46元/hm2,平均相對誤差為1.28%,決定繫數達0.9997,模型擬閤精度高,汎化能力彊,能夠滿足中齡林林木資源資產批量評估的要求。
비량평고구유효솔고、비용저차만족대량평고등우점。논문이중령림위례,장BP신경망락응용우림목자원자산비량평고。통과비교학습산법、은함층절점수,운용민감성분석법학정영향인자대평고치적공헌정도,사선수입층인자,종이우화료림목자원자산비량평고BP신경망락모형결구。결과표명:패협사정칙화법우우L-M산법;년령、리솔、축적、수충위강영향인자,저4개인자대평고치적공헌도초과60%;최우모형결구위BR 9-10-1,해모형평균절대오차위32.46원/hm2,평균상대오차위1.28%,결정계수체0.9997,모형의합정도고,범화능력강,능구만족중령림림목자원자산비량평고적요구。
Mass appraisal is of high efficiency,high precision,low cost,satisfies the needs of vast-amount evaluation.In this study,BP neural network was applied to mass appraisal of mid-age forest assets evaluation. By comparing different learning algorithms and the numbers of hidden layer nodes,selecting layer factors,using sensitivity analysis method which revealed the factors’ influence degree to the assessed value,the model struc-ture of BP neural network was optimized.The results showed that Bayesian regularization method was better than L-M algorithm;the contribution to the assessed values of the four factors including age,rate,accumula-tion,tree species was more than 60%;the best model structure was BR9-10-1.Its mean absolute error was 32.46 yuan/hm2 ,mean absolute percentage error was 1.28%,and decision coefficient was 0.999 7.The model has high fitting accuracy and generalization ability thus meets the requirement of mass appraisal of mid-age forest resource assets.