STEM help / Basic concepts

3.9.1 Drawing graphs of results

You can look at the results in two different formats – as graphs or as tables of results. We will look at the results for Demand; the total Resources installed and the incremental units of installed Resources and the Service Operating Costs.

Demand

  1. Select Draw… from the Graphs menu to access the Draw Graphs dialog. This dialog contains an alphabetical list of the graphs associated with each major type of element.

Figure 1: The Draw Graphs Dialog

  1. Select Service Demand – Connections and click OK or double-click on the graph name. A graph of the Service Demand in Connections is displayed.

Figure 2: Service Demand in Connections

This is a graph of the demand data that you entered for the Service. You can confirm this by switching to the Editor program and viewing the graph of the Market Segment Size. (Note that the two graphs are exactly the same because the Penetration is a constant of 1.)

  1. Select Editor from the STEM menu on the main menu bar or use <Alt+Tab> to switch to the Editor program. The Editor is displayed.
  2. Double-click on the Market Segment icon Households to display the pop-up menu.
  3. Select Details and access the Market Segment Size dialog by left-clicking on the small button to the right of the Size field (when field selected).
  4. Click on the Graph button from the dialog menu to display a graph of the data for the Market Segment.
  5. Compare this graph with the one obtained in the Results program.
  6. Select Results from the STEM menu to return to the Results program.

Resource Installed and Incremental Units

To view the graph for Resource Installed and Incremental Units, select Draw… from the Graph menu and choose Resource Installed and Incremental Units.

This graph shows the total number of Resources that have been installed over the run period of the model, together with the number of new units installed each year as a result of the increase in demand and the replacement of Resources which have come to the end of their physical life.

Figure 3: Resource Installed & Incremental Units

Note that in the first year (2001), 10 units of Resource are installed, i.e., a total capacity of 1000 Erlangs to satisfy the demand from 10 000 connections. During 2002, 10 more Analogue Local Exchanges are installed to meet the growing demand. Note also that from 2003 to 2005, 4 or 5 more Analogue Exchanges are added each year to satisfy incremental demand which is steadily rising.

After 2005, more Resources are installed than can be accounted for by the increase in demand. The reason for this is that the Resources which were installed at the beginning of the model run are coming to the end of their 5-year lifetime. As a result, new Analogue Exchanges are being installed to replace the worn out ones as well as to satisfy incremental demand.

You can see what the exact figures are that make up the graph by using the Show Graph as Table command from the Format menu or by right-clicking on a blank area of the graph and then selecting the command.

Figure 4: Installed and Incremental Units displayed as a table

Service Operating Costs

Use the Draw… command from the Graphs menu and select the Service Charges graph. The charges are composed of Operating Costs, Depreciation and Amortisation, Stock Charge and Operating Charge.

Figure 5: Graph of Service Charges

There is one more interesting graph in the current model, the Service Expenditures graph. Select Draw… from the Graphs menu and open this graph.

Note the shape of the graph reflects that of Resource Installed and Incremental Units. Every five years, Capital Expenditure peaks as the Resources which have a lifetime of five years are replaced. Operating Expenditure is the sum of Capital Expenditure and Operating Costs.

Figure 6: Graph of Service Expenditures

 

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