This site is to serve as my note-book and to effectively communicate with my students and collaborators. Every now and then, a blog may be of interest to other researchers or teachers. Views in this blog are my own. All rights of research results and findings on this blog are reserved. See also http://youtube.com/c/hongqin @hongqin
Tuesday, October 20, 2020
guest lecture at U of Arkansas bioinformatics seriees
Tuesday, October 13, 2020
Thursday, October 8, 2020
Wednesday, October 7, 2020
Heckman correction
https://en.wikipedia.org/wiki/Heckman_correction
"Conceptually, this is achieved by explicitly modelling the individual sampling probability of each observation (the so-called selection equation) together with the conditional expectation of the dependent variable (the so-called outcome equation)"
The Heckman used Mills ratio to model right-censored data as 'selection bias'.
selection bias corrected by Mills ratio (inverse of Gompertz mortality rate?)
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3659766
`selection bias' using the inverse Mills ratio neglected by epidemiologists.
https://en.wikipedia.org/wiki/Mills_ratio
Mills ratio is the Survival function / pdf,
The Gompertz function is u = - dS/dt * 1/S, so, HQ thinks Mills ratio is the inversion of the Gompertz mortality rate.
related to
https://en.wikipedia.org/wiki/Heckman_correction
smoothing parameter
over-smoothed curves may lose some details
rough or over-sensitive smoothed curse may be too noisy. An ideal choice of smoothing parameter can be obtained by appropriately contructed error measures, such as residuals.
Ref: Sharma, 2000, J of hydrology, seasonal to interannaul rainfall probabilistic forecasts for improved water supply management.
mutual information criterion for time series analysis
mutual information criterion for time series analysis
cran
https://rdrr.io/cran/tseriesChaos/man/mutual.html
Tuesday, October 6, 2020
Monday, October 5, 2020
how to cite ERS5-land
How to cite ERA5-Land
(1) Please acknowledge the use of ERA5-Land as stated in the Copernicus C3S/CAMS License agreement:
"5.1.2 Where the Licensee communicates or distributes Copernicus Products to the public, the Licensee shall inform the recipients of the source by using the following or any similar notice: 'Generated using Copernicus Climate Change Service Information [Year]'.
5.1.3 Where the Licensee makes or contributes to a publication or distribution containing adapted or modified Copernicus Products, the Licensee shall provide the following or any similar notice: 'Contains modified Copernicus Climate Change Service Information [Year]';
Any such publication or distribution covered by clauses 5.1.1 and 5.1.2 shall state that neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus Information or Data it contains."
(2) cite the ERA5-Land dataset (as part of the bibliography) as follows:
- For "ERA5-Land hourly data from 1981 to present" downloaded from the Climate Data Store:
Muñoz Sabater, J., (2019): ERA5-Land hourly data from 1981 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). (<date of access>), 10.24381/cds.e2161bac
- For "ERA5-Land monthly averaged data from 1981 to present" downloaded from the Climate Data Store:
Muñoz Sabater, J., (2019): ERA5-Land monthly averaged data from 1981 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). (<date of access>), 10.24381/cds.68d2bb30
Saturday, October 3, 2020
Thursday, October 1, 2020
cross correlation between two time series
I checked the ccf function which calculates the correlation for x_{t+h} and y_t, so in our case, the ccf( dailyCases (x), dew_points (y) ) report they are positively relative, and the peak happen at arround 7 which says dailyCases lags dew_points or dew_points predict dailyCases in 7 days.

