Identifying changes in new data using previously trained regression model












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$begingroup$


I would like some ideas on the following problem. I have a data $x$:
$$x(y,z) = [x_1(y,z), x_2(y,z), x_3(y,z)]$$
such that they are function of $(y,z)$, but neither of $(y,z)$ is available. Therefore I set up a regression model, such that:
$$tilde{x}_1 = ax_2 + bx_3$$
$$tilde{x}_2 = ax_1 + bx_3 tag{1}$$
$$tilde{x}_3 = ax_1 + bx_2$$



Such model, let's simplify the notation to $tilde{x}_i = ABx_{notin{i}}$, can reflect when there is a change of $x$, other than due to $(y,z)$. This is because the relationship, other than relationship to $(y,z)$ is broken and the model will output $tilde{x}$, which is different from the given $x$.



Now, I also know, that $x_{new}$, that is the new incoming data, can differ from $x$, only in some particular way, lets say:



$$x = n^{(1)}x_{new} + n^{(2)} tag{2}$$



where $n^{(1)}$ and $n^{(2)}$ are vectors, the same dimension as $x$. This gives $2*dim(x)$ unknowns.





QUESTION:



Is it possible to recover the vectors $n^{(1)}$, $n^{(2)}$, given sufficient data $x_{new}$ ?



The whole problem again in simple words. The regression model is trained on $x_{train}$, such that $(1)$ is obtained. Then there is a change in the input $x$, such that $x_{new}$ in $(1)$ produces error. Can I find a function $(2)$, such that $x_{new}$ in $(2)$, will give $x$ using $(1)$ ?



Is there any material/technique that could help me to analyze this situation / solve the problem ?





P.S.



I have simply plugged $(2)$ into $(1)$, and using at least 2 $x_{new}$ to obtain $n^{(1)}$, $n^{(2)}$. Why 2 $x_{new}$ ? Because there are $2*dim(x)$ unknowns. This probably should work, but it is non-convex and relatively difficult to optimize.



P.S.2



I can use some stochastic search algorithm, but I would rather try some more mathematically reasoned techniques.










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$endgroup$

















    1












    $begingroup$


    I would like some ideas on the following problem. I have a data $x$:
    $$x(y,z) = [x_1(y,z), x_2(y,z), x_3(y,z)]$$
    such that they are function of $(y,z)$, but neither of $(y,z)$ is available. Therefore I set up a regression model, such that:
    $$tilde{x}_1 = ax_2 + bx_3$$
    $$tilde{x}_2 = ax_1 + bx_3 tag{1}$$
    $$tilde{x}_3 = ax_1 + bx_2$$



    Such model, let's simplify the notation to $tilde{x}_i = ABx_{notin{i}}$, can reflect when there is a change of $x$, other than due to $(y,z)$. This is because the relationship, other than relationship to $(y,z)$ is broken and the model will output $tilde{x}$, which is different from the given $x$.



    Now, I also know, that $x_{new}$, that is the new incoming data, can differ from $x$, only in some particular way, lets say:



    $$x = n^{(1)}x_{new} + n^{(2)} tag{2}$$



    where $n^{(1)}$ and $n^{(2)}$ are vectors, the same dimension as $x$. This gives $2*dim(x)$ unknowns.





    QUESTION:



    Is it possible to recover the vectors $n^{(1)}$, $n^{(2)}$, given sufficient data $x_{new}$ ?



    The whole problem again in simple words. The regression model is trained on $x_{train}$, such that $(1)$ is obtained. Then there is a change in the input $x$, such that $x_{new}$ in $(1)$ produces error. Can I find a function $(2)$, such that $x_{new}$ in $(2)$, will give $x$ using $(1)$ ?



    Is there any material/technique that could help me to analyze this situation / solve the problem ?





    P.S.



    I have simply plugged $(2)$ into $(1)$, and using at least 2 $x_{new}$ to obtain $n^{(1)}$, $n^{(2)}$. Why 2 $x_{new}$ ? Because there are $2*dim(x)$ unknowns. This probably should work, but it is non-convex and relatively difficult to optimize.



    P.S.2



    I can use some stochastic search algorithm, but I would rather try some more mathematically reasoned techniques.










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      I would like some ideas on the following problem. I have a data $x$:
      $$x(y,z) = [x_1(y,z), x_2(y,z), x_3(y,z)]$$
      such that they are function of $(y,z)$, but neither of $(y,z)$ is available. Therefore I set up a regression model, such that:
      $$tilde{x}_1 = ax_2 + bx_3$$
      $$tilde{x}_2 = ax_1 + bx_3 tag{1}$$
      $$tilde{x}_3 = ax_1 + bx_2$$



      Such model, let's simplify the notation to $tilde{x}_i = ABx_{notin{i}}$, can reflect when there is a change of $x$, other than due to $(y,z)$. This is because the relationship, other than relationship to $(y,z)$ is broken and the model will output $tilde{x}$, which is different from the given $x$.



      Now, I also know, that $x_{new}$, that is the new incoming data, can differ from $x$, only in some particular way, lets say:



      $$x = n^{(1)}x_{new} + n^{(2)} tag{2}$$



      where $n^{(1)}$ and $n^{(2)}$ are vectors, the same dimension as $x$. This gives $2*dim(x)$ unknowns.





      QUESTION:



      Is it possible to recover the vectors $n^{(1)}$, $n^{(2)}$, given sufficient data $x_{new}$ ?



      The whole problem again in simple words. The regression model is trained on $x_{train}$, such that $(1)$ is obtained. Then there is a change in the input $x$, such that $x_{new}$ in $(1)$ produces error. Can I find a function $(2)$, such that $x_{new}$ in $(2)$, will give $x$ using $(1)$ ?



      Is there any material/technique that could help me to analyze this situation / solve the problem ?





      P.S.



      I have simply plugged $(2)$ into $(1)$, and using at least 2 $x_{new}$ to obtain $n^{(1)}$, $n^{(2)}$. Why 2 $x_{new}$ ? Because there are $2*dim(x)$ unknowns. This probably should work, but it is non-convex and relatively difficult to optimize.



      P.S.2



      I can use some stochastic search algorithm, but I would rather try some more mathematically reasoned techniques.










      share|cite|improve this question









      $endgroup$




      I would like some ideas on the following problem. I have a data $x$:
      $$x(y,z) = [x_1(y,z), x_2(y,z), x_3(y,z)]$$
      such that they are function of $(y,z)$, but neither of $(y,z)$ is available. Therefore I set up a regression model, such that:
      $$tilde{x}_1 = ax_2 + bx_3$$
      $$tilde{x}_2 = ax_1 + bx_3 tag{1}$$
      $$tilde{x}_3 = ax_1 + bx_2$$



      Such model, let's simplify the notation to $tilde{x}_i = ABx_{notin{i}}$, can reflect when there is a change of $x$, other than due to $(y,z)$. This is because the relationship, other than relationship to $(y,z)$ is broken and the model will output $tilde{x}$, which is different from the given $x$.



      Now, I also know, that $x_{new}$, that is the new incoming data, can differ from $x$, only in some particular way, lets say:



      $$x = n^{(1)}x_{new} + n^{(2)} tag{2}$$



      where $n^{(1)}$ and $n^{(2)}$ are vectors, the same dimension as $x$. This gives $2*dim(x)$ unknowns.





      QUESTION:



      Is it possible to recover the vectors $n^{(1)}$, $n^{(2)}$, given sufficient data $x_{new}$ ?



      The whole problem again in simple words. The regression model is trained on $x_{train}$, such that $(1)$ is obtained. Then there is a change in the input $x$, such that $x_{new}$ in $(1)$ produces error. Can I find a function $(2)$, such that $x_{new}$ in $(2)$, will give $x$ using $(1)$ ?



      Is there any material/technique that could help me to analyze this situation / solve the problem ?





      P.S.



      I have simply plugged $(2)$ into $(1)$, and using at least 2 $x_{new}$ to obtain $n^{(1)}$, $n^{(2)}$. Why 2 $x_{new}$ ? Because there are $2*dim(x)$ unknowns. This probably should work, but it is non-convex and relatively difficult to optimize.



      P.S.2



      I can use some stochastic search algorithm, but I would rather try some more mathematically reasoned techniques.







      optimization regression machine-learning






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      asked Jan 21 at 13:14









      Martin GMartin G

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