Data Flow Diagrams (DFD)

This DFD sample was created on the base of the figure from the NASA website. [asd-www.larc.nasa.gov/ ATBD/ DFD.html]
"Clouds and the Earth's Radiant Energy System (CERES).
EOS-Terra: Understanding Earth's Clouds and Climate.
The Clouds and the Earth's Radiant Energy System (CERES) instrument is one of several that will be flown aboard the Earth Observing System's Terra spacecraft, scheduled for launch in late1999. The data from the CERES instrument will be used to study the energy exchanged between the Sun; the Earth's atmosphere, surface and clouds; and outer space.
The CERES EOS-Terra instrument will be the second CERES instrument in Earth orbit. The first CERES instrument is currently orbiting the Earth aboard the Tropical Rainfall Measuring Mission observatory, which was launched in November 1997. Early results of the TRMM mission show that the first CERES has provided better measurement capabilities than any previous satellite instrument of its kind.
What CERES Will Measure.
CERES will measure the energy at the top of the atmosphere, as well as estimate energy levels in the atmosphere and at the Earth's surface. Using information from very high resolution cloud imaging instruments on the same spacecraft, CERES also will determine cloud properties, including cloud amount, altitude, thickness, and the size of the cloud particles. All of these measurements are critical for advancing our understanding of the Earth's total climate system and further improving climate prediction models.
The CERES instrument is based on NASA Langley's highly successful Earth Radiation Budget Experiment (ERBE) which used three satellites to provide global energy budget measurements from 1984 to 1990." [nasa.gov/ centers/ langley/ news/ factsheets/ CERES.html]
The DFD example "CERES data flow diagram" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Data Flow Diagrams solution from the Software Development area of ConceptDraw Solution Park.

This example was redesigned from the Wikipedia file: LastResortHotel BookRoom Process.png. [en.wikipedia.org/ wiki/ File:LastResortHotel_ BookRoom_ Process.png]
This file is licensed under the Creative Commons Attribution-ShareAlike 3.0 License. [creativecommons.org/ licenses/ by-sa/ 3.0/ ]
"Event partitioning is an easy-to-apply systems analysis technique that helps the analyst organize requirements for large systems into a collection of smaller, simpler, minimally-connected, easier-to-understand ‘mini systems’ / use cases. ...
Defining requirements.
Single process in a fictitious hotel using data flow diagram notation.
Single use case in a fictitious hotel using use case diagram notation.
This approach helps the analyst to decompose the system into ‘mentally bite-sized’ mini-systems using events that require a planned response. The level of detail of each response is at the level of ‘primary use cases’. Each planned response may be modelled using DFD notation or as a single use case using use case diagram notation.
The basic flow within a process or use case can usually be described in a relatively small number of steps, often fewer than twenty or thirty, possibly using something like ‘structured English’. Ideally, all of the steps would be visible all at once (often a page or less). The intention is to reduce one of the risks associated with short-term memory, namely, forgetting what is not immediately visible (‘out of sight, out of mind’). ...
Single process in a fictitious hotel using data flow diagram notation." [Event partitioning. Wikipedia]
The DFD example "Last resort hotel book room process" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Data Flow Diagrams solution from the Software Development area of ConceptDraw Solution Park.