Class Exercise Architectural Patterns

A manufacturing process must maintain the pH of a solution in a vat within certain bounds. The pH of the vat is monitored by taking samples every 12 minutes using six pH sensors located at various places in the vat. The samples are stored, and every 12 minutes a control chart is produced showing a moving window of the most recent sample means. The control chart displays between 10 and 40 data points, along with quality control statistics. Its parameters are set by the user. The program displays and evaluates the control chart, as well as flagging the out-of-control points (data points indicating that the process may be out of control). The program stores all data permanently in data files for later analysis. Each data file contains one days pH readings, along with the times the readings were taken. The program redraws the control chart every 12 minutes. It is also redrawn whenever the user changes any of the parameters governing the chart. This program must be highly reliable. It must accommodate several kinds of pH sensors and allow new brands of sensors to be introduced later. Control charts are an established technique for monitoring industrial processes and are not likely to change.

Q1. Propose a Pipe-and-Filter-style architecture for the Process Monitor program. Draw a diagram to illustrate your design, explain what each filter does, and discuss filter synchronization. Q2. Propose a Blackboard architecture for the Process Monitor program. Draw a diagram to illustrate your design, explain what each worker does. Q3. Propose a Model-View-Controller architecture for the Process Monitor program. Draw a diagram to illustrate your design and list the responsibilities of the models, views, and controllers in your design. Q4. Evaluate the designs you proposed for the Process Monitor program in the previous exercises and explain which design is the best.