Events Calendar

08 Oct
Biostatistics Seminar:  Robert Krafty (Emory University) - Empirical Frequency Band Analysis of Biomedical Time Series
Event Type

Lectures, Symposia, Etc.

Topic

Research

Target Audience

Faculty, Graduate Students

Website

https://publichealth.pitt.edu/biostat...

University Unit
Department of Biostatistics
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Biostatistics Seminar: Robert Krafty (Emory University) - Empirical Frequency Band Analysis of Biomedical Time Series

This week's biostatistics seminar speaker will be Robert Krafty of Emory University. A former Pitt Biostatistics faculty member, Krafty became chair and Rollins Professor in the Department of Biostatistics and Bioinformatics at the Rollins School of Public Health on September 1, 2020.

Abstract

The frequency-domain properties of many biomedical time series signals such as EEG, fMRI and accelerometry have been found to contain valuable information. Frequency-domain properties of a nonstationary time series are characterized through its time-varying power spectrum, which is a bivariate function that quantifies the magnitude of oscillations at different frequencies and times. To obtain low-dimensional, parsimonious measures from this functional parameter, applied researchers consider collapsed measures of power within local bands that partition the frequency space. Frequency bands commonly used in the scientific literature were historically derived, but they are not guaranteed to be optimal or justified for adequately summarizing information from a given time series process under current study.  In this talk, we discuss a novel unifying approach for deriving and analyzing customized frequency bands. A consistent, frequency-domain, iterative cumulative sum-based scanning procedure is formulated to identify frequency bands that best preserve nonstationary information. A formal hypothesis testing procedure is also developed to test which, if any, frequency bands remain stationary. The proposed method is used to analyze heart rate variability of a patient during sleep and uncovers a refined partition of frequency bands that best summarize the time-varying power spectrum.

Dial-In Information

Please contact Jiebiao Wang (jbwang at pitt.edu) for Zoom meeting information and password.

Thursday, October 8 at 3:50 p.m. to 4:50 p.m.

Virtual Event

Biostatistics Seminar: Robert Krafty (Emory University) - Empirical Frequency Band Analysis of Biomedical Time Series

This week's biostatistics seminar speaker will be Robert Krafty of Emory University. A former Pitt Biostatistics faculty member, Krafty became chair and Rollins Professor in the Department of Biostatistics and Bioinformatics at the Rollins School of Public Health on September 1, 2020.

Abstract

The frequency-domain properties of many biomedical time series signals such as EEG, fMRI and accelerometry have been found to contain valuable information. Frequency-domain properties of a nonstationary time series are characterized through its time-varying power spectrum, which is a bivariate function that quantifies the magnitude of oscillations at different frequencies and times. To obtain low-dimensional, parsimonious measures from this functional parameter, applied researchers consider collapsed measures of power within local bands that partition the frequency space. Frequency bands commonly used in the scientific literature were historically derived, but they are not guaranteed to be optimal or justified for adequately summarizing information from a given time series process under current study.  In this talk, we discuss a novel unifying approach for deriving and analyzing customized frequency bands. A consistent, frequency-domain, iterative cumulative sum-based scanning procedure is formulated to identify frequency bands that best preserve nonstationary information. A formal hypothesis testing procedure is also developed to test which, if any, frequency bands remain stationary. The proposed method is used to analyze heart rate variability of a patient during sleep and uncovers a refined partition of frequency bands that best summarize the time-varying power spectrum.

Dial-In Information

Please contact Jiebiao Wang (jbwang at pitt.edu) for Zoom meeting information and password.

Thursday, October 8 at 3:50 p.m. to 4:50 p.m.

Virtual Event

Topic

Research

Target Audience

Faculty, Graduate Students

University Unit
Department of Biostatistics