> sessionInfo()
R version 3.5.3 (2019-03-11)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200)

Matrix products: default

locale:
[1] LC_COLLATE=Korean_Korea.949 LC_CTYPE=Korean_Korea.949
[3] LC_MONETARY=Korean_Korea.949 LC_NUMERIC=C
[5] LC_TIME=Korean_Korea.949

attached base packages:
[1] stats4  stats  graphics  grDevices utils     datasets   methods
[8] base

other attached packages:
[1] RSQLite_2.1.2

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.3       rstudioapi_0.10  magrittr_1.5      tidyselect_0.2.5
 [5] munsell_0.5.0    bit_1.1-14       colorspace_1.4-1  R6_2.4.0
 [9] rlang_0.4.0      blob_1.2.0       dplyr_0.8.3       tools_3.5.3
[13] grid_3.5.3       gtable_0.3.0     DBI_1.0.0         yaml_2.2.0
[17] digest_0.6.21    bit64_0.9-7      lazyeval_0.2.2    assertthat_0.2.1
[21] tibble_2.1.3     mongolite_2.1.0  crayon_1.3.4      purrr_0.3.2
[25] ggplot2_3.2.1    vctrs_0.2.0      zeallot_0.1.0     rpart_4.1-15
[29] memoise_1.1.0    glue_1.3.1       compiler_3.5.3    pillar_1.4.2
[33] backports_1.1.4  scales_1.0.0     jsonlite_1.6      pkgconfig_2.0.3