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iterative_bns [2019/03/27 17:35] – created stritihaiterative_bns [2023/04/21 15:30] (current) – external edit 127.0.0.1
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 ====Iterative BNs==== ====Iterative BNs====
  
-Bayesian Networks usually represent a static state of the studied system, and **feedback loops** cannot be incorporated. To take into account changes over time, including feedbacks, we can use dynamic BNs, using the so-called “time-slicing” approach. In practice, this means that each time step is represented by a run of the network, where the **outputs of one step are used as inputs to the next** time step. +Bayesian Networks usually represent a static state of the studied system, and **feedback loops** cannot be incorporated. To take into account changes over time, including feedbacks, we can use dynamic BNs, using the so-called “time-slicing” approach. gBay uses a simplified version of this approach, where each time step is represented by a run of the network, where the **outputs of one step are used as inputs to the next** time step. 
  
 For example, when modelling carbon storage over time, we start with an estimate of the forest biomass at the beginning of the first time step (//Biomass//). During one time step, growth and harvesting take place, and through inference we obtain the probability distribution of land use after the first time step (//Biomass1//, e.g. after 10 years). This //Biomass1// then becomes the input for //Biomass// in the second time step.  For example, when modelling carbon storage over time, we start with an estimate of the forest biomass at the beginning of the first time step (//Biomass//). During one time step, growth and harvesting take place, and through inference we obtain the probability distribution of land use after the first time step (//Biomass1//, e.g. after 10 years). This //Biomass1// then becomes the input for //Biomass// in the second time step. 
  
-In gBay, we create such a dynamic BN by specifying links across time steps. To do this, click the option **“Link”** on the output node that should feed into the input of the next time step (//Biomass1//). An orange arrow will appear, which should be connected to the corresponding input node (//Biomass//). +In gBay, we create such an iterative BN by specifying links across time steps. To do this, click the option **“Link”** on the output node that should feed into the input of the next time step (//Biomass1//). An orange arrow will appear, which should be connected to the corresponding input node (//Biomass//). 
  
 {{:gbay_dynamic.png?900|}} {{:gbay_dynamic.png?900|}}
iterative_bns.1553704502.txt.gz · Last modified: 2023/04/21 15:30 (external edit)