HiFlow: Training-free High-Resolution Image Generation with Flow-Aligned Guidance - Bu, Jiazi; Ling, Pengyang; Zhou, Yujie; Zhang, Pan; Wu, Tong; Dong, Xiaoyi; Zang, Yuhang; Cao, Yuhang; Lin, Dahua; Wang, Jiaqi (Advances in Neural Information Processing Systems, 2025)