This package provides tools for simulating the collisions of ships with whales, using a simplified dynamical structure involving point masses separated by compressible materials. Along with functions for computations of forces, deformations, accelerations, etc., the package provides a easy-to-use GUI tool that makes it easy to set up some common simulation scenarios, and to display the results in graphical form.
To learn more about the scientific background, and to see the results of some detailed computations placed in the context of a database of observed strikes, see Kelley et al. (2021). For more information on the coding, see Kelley (2024).
The package is not yet available on CRAN, and must be installed from source. This can be done either by downloading the source and building it locally, or by the simpler method of typing
# install.package("remotes")
remotes::install_github("dankelley/whalestrike", ref="main")in an R session. (Uncomment the first line, if the remotes
package is not yet installed on your machine.)
Most users will find that the GUI application is a good way to learn about the package. To start this, type
library(whalestrike)
app2()in an R session. A window will open in your browser. On the
left-hand side is a region with controllers, many hidden in sub-panels
that can be opened by clicking on V-shaped icons. Before opening
those sub-panels, try adjusting the ship speed, to see what happens to
the plots, especially the one labelled Lethality Index. Think about
whether the tendency of variations to the index are in line with your
intuition. Next, open the Ship sub-panel, to explore the result of
altering the ship mass. This sub-panel also has controllers
specifying the geometry of the impact region, and you ought to explore
them, also. Continuing to explore the app's controllers ought to give
you a good indication of what the tool provides. To learn more, try
consulting the app's documentation, provided (a) as the response to
typing ? app2 in the R console, (b) as information in a dialog box
that opens when the Help button is clicked, and (c) in a youtube
video and a brief followup youtube
video that illustrates an alteration
made after a helpful comment from a review of a Journal of Open-Source
Software manuscript about the package.
Users who want more control, and who want to deal with the results in
numerical as opposed to graphical form, should try clicking the Code
button in app2(), to see the R code that runs the simulation outside
the app. The next step will be to explore the functions used in that
code. Documentation exists for each of these functions e.g. typing
library(whalestrike)
?strikein an R session will provide information on strike(), which is a key
function in the package.
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Kelley, Dan E., James P. Vlasic, and Sean W. Brillant. "Assessing the Lethality of Ship Strikes on Whales Using Simple Biophysical Models." Marine Mammal Science 37, no. 1 (January 2021): 251–67. https://doi.org/10.1111/mms.12745. (journal site; ResearchGate Preprint)
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Kelley, Dan E. "Whalestrike: an R package for simulating ship strikes on whales". Submitted to Journal of Open Source Software, 2024-01-29.