My research interest lies in the field of observational cosmology, especially aimed at understanding how hierarchical structures of the Universe have been formed. The standard scenario predicts that cosmic structures are formed as a result of amplification of primordial seed fluctuations due to gravitational instability mainly driven by dark matter. In addition, another mysterious component (to cause the present-day cosmic acceleration), dark energy affects structure formation through ``the effect on cosmic expansion. Finally, the Big Bang relic neutrinos’finite masses imprint characteristic features onto large-scale structures. Therefore, a detailed study of the properties and time evolution of structure formation processes using cosmological observations allows us to explore the nature of dark matter, dark energy and neutrinos. This is the final goal of my research.