社交网络建模
偏移 Gompertz 分布是按独立指数和极值分布的随机变量的最大值的分布. 该分布可用于模拟社交网络关注的增长和下降. 以下为偏移 Gompertz 分布的 CDF 形式.
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CDF[ShiftedGompertzDistribution[\[Lambda], \[Xi]], x]
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谷歌趋势(Google trends)的 Facebook 中的每周关注计数.
In[2]:=

ts = TemporalData[TimeSeries, {CompressedData["
1:eJyFz2tPwjAUBmDA+7wRNCpeQBTRiAGvXLoNYYytPW03QHSybiYav/tX/Ume
GRO/mPg0p+l72pykpbeP8VsmlUqlsT5xS/8n82smM/Nt9sdcYv4vC2gxoWlL
mqYto5WVVbS2tp7N5nK5jY3N7Z2tnXx+d3dvbx/XQbFwUCgUi4eHpdLRcbl8
UjmtnJ1XqxeoVqvV65dX9cvrZvP2pnHXaLUbjWaLIJMYuk4MwzTNTue+1+1a
qO9a9qA/cPq2PRg4ILnLgHPGgLkuABfSdRyHUs5AAghvyD3peb4U+IhLJoCB
NxLUk0JwgXcCRNIT2AYpPS4YByo5cGBsFL+oOFaRCqP4/VWpOFQqCKbhVEXh
9BmFKopjTFEQBs9PweRxNHkYj/yh7/ueEHI8xDGAg7AAqMsodRw3OTP2HWxK
XfyFbVl2z+p2kGn1jATRSZsQXW+RNkpSmxjkC/7xXxc=
"], {
TemporalData`DateSpecification[{2006, 8, 26, 0, 0, 0.}, {
2015, 7, 11, 0, 0, 0.}, {1, "Week"}]}, 1, {"Continuous", 1}, {
"Discrete", 1}, 1, {
ValueDimensions -> 1, DateFunction -> Automatic,
ResamplingMethod -> {"Interpolation", InterpolationOrder -> 1}}},
True, 314.1];
显示完整的 Wolfram 语言输入
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用截断偏移 Gompertz 分布拟合数据.
In[4]:=

rawcounts = ts["Values"];
length = Length[rawcounts];
x = Range[length] - 0.5;
wdata = WeightedData[x, rawcounts];
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edist = EstimatedDistribution[wdata,
TruncatedDistribution[{0, length},
ShiftedGompertzDistribution[\[Lambda], \[Xi]]], {{\[Lambda],
1}, {\[Xi], 6}}]
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比较模型预测和数据.
显示完整的 Wolfram 语言输入
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