Use Case: Determination of Physical Conditions in Interstellar Clouds from observed column densities


An astronomer studies a particular interstellar cloud for which he gathered column densities of some observed atoms and molecules. He searches the registries to find a grid of precalculated results. Registries point towards: a grid of precalculated results from a PDR code, the software aimed to search informations in the grid and the PDR code used to build the grid.
  1. He sends to the software the required informations to build a chi^2 and indicates which physical quantities he wants to consider as parameters (these parameters have to be the variables of the grid).
  2. Software searches the grid trying to minimize the chi^2 with the authorized physical quantities as parameters. Result in the form of a table is sent to the user (Human readable format). This result is a first order solution to his problem.
  3. Now the user tries to precisely study his line of sight. He sends a request to the PDR code with parameters guessed from the result he get in the first process and specific parameters to his line of sight which were not incorporated in the grid.
  4. He iterates on step C until he finds a satisfactory result.

Primary Actor


Secondary Actor


Pre Conditions


Flow of events

  1. user browses registries to find an appropriate grid.
  2. user selects services
  3. user sends informations to build a chi^2 and the physical quantities he wants to use as parameters
  4. Service searches the grid of results to find a solution. This solution is send back to the user (human readable format)
  5. User sends a request to the simulation code
  6. Service sends the result of the simulation to the user in a human readable format

Post Conditions


Please add comments below. This area should be used for refinement of the above document. If you want to ask questions or start a dialogue with the author, please use the theory mailing list.

-- FranckLePetit - 28 Sep 2005

Topic revision: r1 - 2005-09-28 - FranckLePetit
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