将剩余产量模型和时滞差分模型分别应用于南大西洋长鳍金枪鱼（Thunnus alalunga）渔业数据,结果表明,比起剩余产量模型,时滞差分模型拟合的单位捕捞努力渔获量（catch per unit effort,CPUE）曲线能够更好地捕捉到CPUE随着时间的波动...将剩余产量模型和时滞差分模型分别应用于南大西洋长鳍金枪鱼（Thunnus alalunga）渔业数据,结果表明,比起剩余产量模型,时滞差分模型拟合的单位捕捞努力渔获量（catch per unit effort,CPUE）曲线能够更好地捕捉到CPUE随着时间的波动。赤池信息量准则（Akaike information criterion,AIC）的结果显示,时滞差分模型比Schaefer模型的评估效果要好。时滞差分模型评估的最大可持续产量（maximum sustainable yield,MSY）中值为22 490 t,80%置信区间为21 756~23 408 t;剩余产量模型评估的MSY中值为27 520 t,80%的置信区间为26 116~28 959 t。生物学参考点的结果表明目标群体在1985年以前资源状态较好;1985年~2005年的20年里处于过度捕捞状态;2005年后资源状况得到改善,但仍需加强管理。比起剩余产量模型,时滞差分模型给出了更为有效且保守的评估结果。展开更多
南大西洋长鳍金枪鱼群体是全球资源状况维持较好的金枪鱼群体之一,剩余产量模型(Surplus production model,SPM)、年龄结构模型(Age-structured population model,ASPM)和贝叶斯产量模型(Bayesian surplus production model,BSPM)等都...南大西洋长鳍金枪鱼群体是全球资源状况维持较好的金枪鱼群体之一,剩余产量模型(Surplus production model,SPM)、年龄结构模型(Age-structured population model,ASPM)和贝叶斯产量模型(Bayesian surplus production model,BSPM)等都已成功运用于该群体的资源评估。连续型时滞差分模型(Continuous delay-difference model,CTD-DM)是在时滞差分模型(Delay-difference model,D-DM)基础上考虑了生物过程充分时间延迟构建起来的模型,比起ASPM需要较少的数据,并且比SPM更具有生物学意义。本文在离散型D-DM基础上构建了CTD-DM,并应用在南大西洋长鳍金枪鱼渔业数据中。结果显示,CTD-DM评估的最大可持续产量(Maximum Sustainable Yield,MSY)80%置信区间为21510-23118 t(中值22398 t),较ASPM和SPM等MSY评估结果偏保守。相对生物量B2011/BMSY和相对捕捞死亡系数F2011/FMSY分别为1.45和1.04,当前该群体相对资源量水平较好,但是相对捕捞死亡系数较高;BSPM和CTD-DM的风险评估结果显示,当捕捞死亡率均等于0.2时在2025年取得最大持续产量,考虑到当前渔业持保守态度和预防性策略的理念,建议捕捞死亡率应控制在0.15以内。展开更多
The problem of discrete-time model identification of industrial processes with time delay was investigated.An iterative and separable method is proposed to solve this problem,that is,the rational transfer function mod...The problem of discrete-time model identification of industrial processes with time delay was investigated.An iterative and separable method is proposed to solve this problem,that is,the rational transfer function model parameters and time delay are alternately fixed to estimate each other.The instrumental variable technique is applied to guarantee consistent estimation against measurement noise.A noteworthy merit of the proposed method is that it can handle fractional time delay estimation,compared to existing methods commonly assuming that the time delay is an integer multiple of the sampling interval.The identifiability analysis for time delay is addressed and correspondingly,some guidelines are provided for practical implementation of the proposed method.Numerical and experimental examples are presented to illustrate the effectiveness of the proposed method.展开更多
文摘南大西洋长鳍金枪鱼群体是全球资源状况维持较好的金枪鱼群体之一,剩余产量模型(Surplus production model,SPM)、年龄结构模型(Age-structured population model,ASPM)和贝叶斯产量模型(Bayesian surplus production model,BSPM)等都已成功运用于该群体的资源评估。连续型时滞差分模型(Continuous delay-difference model,CTD-DM)是在时滞差分模型(Delay-difference model,D-DM)基础上考虑了生物过程充分时间延迟构建起来的模型,比起ASPM需要较少的数据,并且比SPM更具有生物学意义。本文在离散型D-DM基础上构建了CTD-DM,并应用在南大西洋长鳍金枪鱼渔业数据中。结果显示,CTD-DM评估的最大可持续产量(Maximum Sustainable Yield,MSY)80%置信区间为21510-23118 t(中值22398 t),较ASPM和SPM等MSY评估结果偏保守。相对生物量B2011/BMSY和相对捕捞死亡系数F2011/FMSY分别为1.45和1.04,当前该群体相对资源量水平较好,但是相对捕捞死亡系数较高;BSPM和CTD-DM的风险评估结果显示,当捕捞死亡率均等于0.2时在2025年取得最大持续产量,考虑到当前渔业持保守态度和预防性策略的理念,建议捕捞死亡率应控制在0.15以内。
文摘The problem of discrete-time model identification of industrial processes with time delay was investigated.An iterative and separable method is proposed to solve this problem,that is,the rational transfer function model parameters and time delay are alternately fixed to estimate each other.The instrumental variable technique is applied to guarantee consistent estimation against measurement noise.A noteworthy merit of the proposed method is that it can handle fractional time delay estimation,compared to existing methods commonly assuming that the time delay is an integer multiple of the sampling interval.The identifiability analysis for time delay is addressed and correspondingly,some guidelines are provided for practical implementation of the proposed method.Numerical and experimental examples are presented to illustrate the effectiveness of the proposed method.
