Where and How to Perturb: On the Design of Perturbation Guidance in Diffusion and Flow Models - Ahn, Donghoon; Kang, Jiwon; Lee, Sanghyun; Kim, Minjae; Jang, Wooseok; Min, Jaewon; Lee, Sangwu; Paul, Sayak; Kim, Seungryong (Advances in Neural Information Processing Systems, 2025)