This book contains select proceedings of EPREC-2021 with a focus on power electronics and drives. The book includes original research and case studies that present recent developments in power electronics focusing on power inverters and converters. The book also consists of research work on electrical drives, regulated power supplies, operation of FACTS & HVDC, etc. The book will be a valuable reference guide for beginners, researchers, and professionals interested in the advancements of power electronics and drives.

Surveys dealing with multiple observations spread over time are defined as longitudinal surveys. When one is concerned about estimates of population sub-groups in longitudinal surveys, particularly the pattern of changes at individual level as well as aggregate level over time, the techniques of small areas estimation (SAE) can possibly be employed to achieve the above goal. In this book, it has been attempted to propose methodology for estimation of population parameters in longitudinal surveys with special reference to small area and study the temporal patterns of changes in population parameters. Direct, synthetic and composite estimators have been proposed to estimate the population mean of small area for specific points of time. It also provides detail of mean square errors (MSE) of the proposed estimator. The relative efficiencies of the proposed estimators are illustrated with an empirical data collected through surveys.