Display and Internal Operation Flow as shown in Table 1. In addition to the conventional DFD development guideline, the Process and Display is used to represent a display interface of a process component. Note that interfaces will be created for each Process and Display function and will be used in ESTD later.
The Internal Operation Flow, drawn in a bold dashed line, represents the information flow between users and Process and Display via internal operations (to be discussed later). The volume of information flow is the essential factor that causes hight memory load.
|Process and Display||
a display symbol on the left upper corner of|
process indicate a display interface required
|Internal Operation||14 = 15 = 16||
a dashed line indicate the internal operations|
The second stage is to develop an ESTD which is altered from STD by adding three functions: Accumulated Display Interface, External Operation Flow, and Exclusive Operator (please refer to Table 2). The Accumulated Display Interface (ADI) is an interface accumulated memory load of Non- Accumulated Display Interface (NDI), which is just a simple interface.
The External Operation evaluates the user memory loads of both the Accumulated Display Interfaces and Non-Accumulated Display Interfaces. The external operations of each interface will be shown within each interface block.
The Exclusive Operator function is dedicated to constraining the looping of user operations by limiting the entry and exit following the same interface so that the users will not get lost in the loop.
a gray triangular mark on the left|
upper corner of NDI indicates the
main interface for users
|External Operation||description of external operations||no|
a circle with cross line indicates|
the constraint of entry and exit of
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Publication information: Book title: Human-Computer Interaction:Communication, Cooperation, and Application Design. Contributors: Hans-Jörg Bullinger - Editor, Jürgen Ziegler - Editor. Publisher: Lawrence Erlbaum Associates. Place of publication: Mahwah, NJ. Publication year: 1999. Page number: 54.
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