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Error Modeling

CADET-Match includes error modeling and parameter estimation. Error modeling in CADET-Match is based on using a fitted simulation and creating an error model by manipulations to the fitted simulation. Error modeling uses MCMC and can be a slow process which requires a lot of computing time. Some simple problems can be solved in a few hours on a powerful desktop and others can take weeks on a powerful server.

MCMC search settings.

The error model is pretty simple. The best fit simulation is used as a template. Variations are made based on the template using the errors supplied.

Pump Delays are implemented using a uniform random distribution. Any time a new section starts in CADET a pump delay may be applied. Setting upper and lower bound to 0 disables this error.

Flow rate variations use a normal distribution with a supplied mean and standard deviation. These numbers can usually be found from a pump manufacturer. The flow rate in the simulation is multiplied by the pump flow error. Setting the mean to 0 disables this error.

Loading concentration variations use a normal distribution with a supplied mean and standard deviation. These numbers normally have to be determined from experiments. The concentration is multiplied by the concentration error. Setting the mean to 0 disables this error.

The UV error is modeled as a scale dependent error and a scale indepdennt error so that the total error applied to the chromatogram = signal * uv_noise_norm + uv_noise. Both of the errors sources are the same length as the chromatogram. UV noise norm almost always has a mean value of 1.0 and UV noise almost always has a mean noise of 0.0 since they are the multiplicative and additive identities respectively.

Key	Values	Default	Required	Description
name	String	None	Yes	name of the experiment this error model applies to
units	List of Integers	None	Yes	unit numbers that uv noise should be applied to
delay	[Float, Float]	None	Yes	min and max value of a uniform random distribution for pump delays
flow	[Float, Float]	None	Yes	mean and standard deviation for a normal distribution
load	[Float, Float]	None	Yes	mean and standard deviation for a normal distribution
uv_noise_norm	[Float, Float]	None	No	mean and standard deviation for a normal distribution
uv_noise	[Float, Float]	None	No	mean and standard deviation for a normal distribution

"errorModel": [
        {
                "file_path": "non.h5",
                "experimental_csv": "non.csv",
                "name": "main",
                "units": [2],
                "delay": [0.0, 2.0],
                "flow": [1.0, 0.001],
                "load": [1.0, 0.001],
                "uv_noise_norm": [1.0, 0.001]
        }
],