I work on several topics in theoretical and observational cosmology. In particular, I have been focusing on Type Ia supernovae (SNe Ia) and Baryon Acoustic Oscillations (BAOs) as standard rulers to measure the cosmological distance and the evolution of dark energy, and studying how the clumpy structure of the Universe affects on the distance measurements, e.g., through weak gravitational lensing or peculiar velocities of galaxies. In the Kavli IPMU, I am now working on the development and improvement of analysis model to constrain the cosmological parameters with higher precision using the galaxy clustering dataset from PFS.