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删除1,831字节 、 2020年9月1日 (二) 17:18
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[[Image:SFDD VAL.gif|centre|年存量和流量值=0至15|frame]]
 
[[Image:SFDD VAL.gif|centre|年存量和流量值=0至15|frame]]
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===连续时间方程 Equations in continuous time===
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===连续时间方程===
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To get intermediate values and better accuracy, the model can run in continuous time: we multiply the number of units of time and we proportionally divide values that change stock levels. In this example we multiply the 15 years by 4 to obtain 60 trimesters, and we divide the value of the flow by 4.<br>
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为了得到中间值和更好的准确性,该模型可以在连续时间内运行: 我们乘以时间单位的数量,并按比例除以改变存量水平的值。在这个例子中,我们把15年乘以4得到60个三个月,然后我们把流量的值除以4。
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To get intermediate values and better accuracy, the model can run in continuous time: we multiply the number of units of time and we proportionally divide values that change stock levels. In this example we multiply the 15 years by 4 to obtain 60 trimesters, and we divide the value of the flow by 4.<br>
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为了得到中间值和更好的准确性,该模型可以在连续时间内运行: 我们乘以时间单位的数量,并按比例除以改变存量水平的值。在这个例子中,我们把15年乘以4得到60个三个月,然后我们把流量的值除以4。 Br
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Dividing the value is the simplest with the [[Euler method]], but other methods could be employed instead, such as [[Runge–Kutta methods]].
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Dividing the value is the simplest with the Euler method, but other methods could be employed instead, such as Runge–Kutta methods.
      
用欧拉法除值是最简单的方法,但也可以用其他方法代替,如龙格-库塔法。
 
用欧拉法除值是最简单的方法,但也可以用其他方法代替,如龙格-库塔法。
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List of the equations in continuous time for trimesters = 1 to 60 :
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List of the equations in continuous time for trimesters = 1 to 60 :
      
连续时间方程列表1至60的三个月:
 
连续时间方程列表1至60的三个月:
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*They are the same equations as in the section ''Equation in discrete time'' above, except equations ''4.1'' and ''4.2'' replaced by following :
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*除将式4.1和式4.2替换为以下形式外,与上述“离散时间方程”一节相同:
 
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<math>10) \ \mbox{Valve New adopters}\ = \mbox{New adopters} \cdot TimeStep </math>
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<math>10) \ \mbox{Valve New adopters}\ = \mbox{New adopters} \cdot TimeStep </math>
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10) mbox { Valve New adopters } mbox { New adopters } cdot TimeStep / math
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<math>10.1) \ \mbox{Potential adopters}\ -= \mbox{Valve New adopters} </math>
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<math>10.1) \ \mbox{Potential adopters}\ -= \mbox{Valve New adopters} </math>
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数学10.1) mbox { Potential adopters } - mbox { Valve New adopters } / math
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<math>10.2) \ \mbox{Adopters}\ += \mbox{Valve New adopters } </math>
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<math>10.2) \ \mbox{Adopters}\ += \mbox{Valve New adopters } </math>
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10.2) mbox { Adopters } mbox { Valve New Adopters } / math
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<math> \ TimeStep = 1/4 </math>
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<math> \ TimeStep = 1/4 </math>
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数学 time step 1 / 4 / math
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<math>10) \ \mbox{Valve New adopters}\ = \mbox{New adopters} \cdot TimeStep </math>
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*In the below stock and flow diagram, the intermediate flow 'Valve New adopters' calculates the equation :
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<math>10.1) \ \mbox{Potential adopters}\ -= \mbox{Valve New adopters} </math>
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<math>10.2) \ \mbox{Adopters}\ += \mbox{Valve New adopters } </math>
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<math> \ TimeStep = 1/4 </math>
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<math> \ \mbox{Valve New adopters}\ = \mbox{New adopters } \cdot TimeStep </math>
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<math> \ \mbox{Valve New adopters}\ = \mbox{New adopters } \cdot TimeStep </math>
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*在下面的库存和流程图中,中间流''Valve新采用者''计算公式:
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{ Valve New adopters } mbox { New adopters } cdot TimeStep / math
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<math> \ \mbox{Valve New adopters}\ = \mbox{New adopters } \cdot TimeStep </math>
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[[Image:Adaption SFD continuous time.png|centre|Dynamic stock and flow diagram of ''New product adoption'' model in continuous time|frame]]
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[[Image:Adaption SFD continuous time.png|centre|连续时间下“新产品采用”模型的动态库存及流程图|frame]]
    
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