OCECgo: A MATLAB Tool for the Sunset Model 4 Instrument

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OCECgo is a MATLAB-based software tool for the quantification of uncertainties in the calibration and data analysis of the Sunset Laboratory Model 4 semi-continuous thermal-optical organic/elemental carbon analyzer.

Table of Contents

• Calibration
  • Introduction
  • Example
  • Instructions for Use
  • Monte Carlo / GUI Inputs
  • References
• Data Analysis
  • Introduction
  • Example
  • Instructions for Use
  • Monte Carlo / GUI Inputs
  • References
• Algorithm Details
  • Introduction
  • Monte Carlo Analysis of Calibration Data
  • NDIR Correction: Convex Hull
  • Split Point Uncertainty: Attenuation Decline
  • Carbon Mass: Posterior Distributions
  • References

Citation and Use

OCECgo is described in an article submitted to the Journal of Visualized Experiments and is being shared free of charge under the MIT license. When using the software for analysis of data in published work, it is requested that users cite/acknowledge the following:

Conrad, B.M. & Johnson, M.R. (2019), Calibration protocol and software for split point analysis and uncertainty quantification of thermal-optical organic/elemental carbon measurements, J. Vis. Exp., 151:e59742 (doi: 10.3791/59742)

Features

The accompanying submission to the Journal of Visualized Experiments includes the step-by-step procedure for using OCECgo to acquire calibration data, analyze measured data, and compute uncertainties. The OCECgo software includes the following features:

• Monte Carlo-based analysis of instrument calibration and associated uncertainties:
  • Consideration of uncertainty in the carbon concentration of the external sucrose standard
  • Consideration of uncertainty in the application of sucrose via pipette during calibration
• Monte Carlo-based analysis of uncertainty in the analysis of OCEC data:
  • Propagation of uncertainty due to calibration and split point estimation
  • Simple and rapid assessment of dominant sources of uncertainty

Installation

OCECgo is available as a source distribution and a build distribution and is hosted on GitHub. If you have a MATLAB license (R2016a or newer), add the “source” directory to the MATLAB path and run “OCECgo”. Alternatively, double-click the “OCECgo_webinstaller” executable in the “build” directory to install a standalone version of the software on your computer.

To clone the OCECgo repository, see GitHub’s instructions.

Note

When booting the software, the landing screen may disappear and it may seem as though booting has stalled. Be patient at this point; the MATLAB runtime is being loaded and OCECgo will initialize shortly after.

Requirements

OCECgo was originally developed and has been tested in MATLAB R2016a and R2018b, and uses the signal_toolbox and statistics_toolbox.

If you encounter issues during installation or when using OCECgo, please contact the author.

Contribute

OCECgo is intended be a research tool that improves over time - your input to introduce and improve functionality would be highly appreciated! Consider contributing in the following ways:

1. Have a bug report? Raise an issue on github.
2. Want to introduce functionality helpful to your work/field? Fork the repository, make it work for you, and issue a pull request. Credit will always be given!

License

OCECgo is licensed under the MIT license:

Copyright (c) 2019 Bradley Conrad

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Author Contact Information

You can contact Bradley (Brad) Conrad with issues and/or recommendations at brad.conrad@carleton.ca or brad.m.conrad@gmail.com

Version History

Version 0.9: Version submitted for review with JoVE article.

Version 1.0: Version/release at time of publication of the JoVE article.

Acknowledgements

OCECgo was developed at Carleton University’s Energy and Emissions Research Laboratory with support from NSERC FlareNet.