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Materials Science in Additive Manufacturing                           Data imputation strategies of PBF Ti64




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            Figure 11. Comparison of the actual and predicted laser scan speed for various models. (A) k-nearest neighbor; (B) multivariate imputation by chained
            equations; (C) graph imputation neural network. See Supplementary File for the out-of-bound outliers.

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            Figure 12. Comparison of the actual and predicted composite parameter (energy density × hatch spacing) for various models. (A) k-nearest neighbor; (B)
            multivariate imputation by chained equations; (C) graph imputation neural network.

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            Figure 13. Strategy to improve quality of imputed dataset. (A) Median of the imputed values obtained from the k-nearest neighbor, multivariate imputation
            by chained equations, and graph imputation neural network. (B) The actual and predicted laser scan speed for the median of the imputed values. (C) The
            actual and composite parameter (energy density × hatch spacing) for the median of the imputed values.

              The accuracy of the imputed results depends on   For example, if the imputed data are to be used for critical
            several factors such as the quality of the original data, the   decision-making  or  safety-critical  applications,  a  more
            imputation method used, and the amount and pattern   rigorous validation process may be necessary to ensure the
            of missing data. In this context, the imputation method   accuracy and reliability of the imputed data.
            used (GINN, MICE, and kNN) was found to be effective   Data imputation is a crucial step in data analysis and
            in reducing the overall RMSE and improving the accuracy   modeling, especially when dealing with missing data.
            of the imputed data. The final imputation strategy, which   Imputation methods such as MICE and kNN can help to
            involved taking the median of the imputed values from   recover missing data and enable more robust and accurate
            the three models, further improved the accuracy of the   data analysis. In addition, imputation can also help to
            imputed data.                                      reduce bias and increase the representativeness of the
              While the results obtained in this study are promising,   data, which can improve the quality of the insights and
            it is important to note that the suitability of the imputed   conclusions derived from the data.
            data for wider implementation or industrial use depends   The value of this work lies in its application of multiple
            on the specific context and requirements of the application.   imputation methods to a real-world dataset in the context


            Volume 2 Issue 1 (2023)                         13                       https://doi.org/10.36922/msam.50
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