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Reading the DSM
A Design Structure Matrix (DSM) is a compact, matrix representation of a project. The matrix contains a list of all constituent activities and the corresponding information exchange patterns. That is, what information pieces (parameters) are required to start a certain activity and where does the information generated by that activity feed into (i.e. which other tasks within the matrix utilize the output information).
The DSM provide insights about how to manage a complex system/project and higlights issues of information needs and requirements, task sequencing, and iterations.
A sample DSM is shown below (Ulrich and Eppinger, 1999)
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B |
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C |
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D |
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E |
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F |
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G |
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H |
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I |
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J |
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K |
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L |
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M |
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The X marks indicate the existence and direction of information flow (or a dependency
in a general sense) from one activity in the project (i.e. matrix) to another. Reading
across a row reveals the input/dependency flows by an X mark placed at the intersection of
that row with the column that bears the name of the input task. Reading across a column
reveals the output information flows from that activity to other activities by placing an
X in a similar manner described above. For example, consider activity C in the above
matrix. Activity C relies on information from activities A and B and delivers information
to activities D, E, F and G.
The GREEN marks (below the diagonal)
represent FORWARD flow of information.
The RED marks (above the diagonal) are of
special significance. Such a mark reveal a FEEDBACK
from a later (i.e. downstream) activity to an earlier (i.e. upstream) one. This means that
the earlier activity has to be repeated/reworked in light of the late arrival of new
information. This iterative process in common in most engineering design and development
projects. Design iterations create rework and require extra comunication and negotiation
which result in a prolonged development process. In order to speed up this iterative
design process, the DSM methodology suggests the manipulation of the matrix elements such
that iterative behavior is removed from the matrix, or at least minimized (a process
called Partitioning).
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