pytorch lightning 설명 lightningModule 레이어변경 densenet implementation U-Net OS #densenet pytorch deep supervision NO_PUBKEY GPG error linux implementation 윈도우 포맷 후 환경설정 segmentation effective batch pytorch lightning lightningDataModule 운영체제 conda segementation java A4B469963BF863CC full-scale skip connection UNet++ interrupt medical imaging PL pytorch layer change MAC