STEM help / Calculation framework

Inputs beginning with ‘C’

Calibration Period

The period when various cost input data apply. Results for other years are calculated using the relevant Cost Trends.

For a Resource: all Costs.

For a Service: Administration and Provision Costs.

Default: Y0. Cost and tariff input data apply at the start of the model run.

Capacity

The amount of demand which is supported by one unit of a Resource.

It is vital that this capacity is consistent with the measure of demand specified by Service and Transformation Requirements.

Default: 1.0.

Capacity Mode

A choice between different capacity dynamics:

Persistent: the full installed capacity of a resource may be used each period and this usually persists for its full physical lifetime.

Consumable: initial installed capacity is gradually used up according to the used capacity in successive periods until an installed unit is removed when it is fully used up.

Default: Persistent.

Capacity Period

A choice of time period which allows for a time-factor to be used to match in-time consumable capacity to instantaneous demand or, conversely, to match per-time persistent capacity to an aggregate demand. For this to work, you must first set the separate input Time Factor = Yes.

Default: Year.

Capacity Unit

The unit of capacity, e.g., Circuits, Connections, Lines. Either type a unit or choose from the drop-down list.

The selection has no mathematical effect on the model, but the text is used to label the y-axis on results graphs.

Default: None.

Capital Cost

The capital cost of one unit of a Resource in the Calibration Period. Resource capital values are written down according to the Financial Lifetime and Depreciation Rate.

For a consumable resource, capital cost is the cost of purchasing one unit of stock which has a non-zero shelf life.

Default: Constant {0.0}.

Capital Cost Structure

The respective proportions of the Capital Cost of a Resource associated with each Cost Index in the Calibration Period. These proportions must sum to one (or zero).

The Capital Cost of each new unit of a Resource, in years other than the Calibration Period, is based on the cost of the Resource in the Calibration Period, modified in accordance with its Capital Cost Structure and the Cost Index Cost Trends.

Alternatively, Capital Costs may be specified more simply using per-Resource or global cost trends, like other Resource costs.

Default: 0.0 for all proportions. The unit Capital Cost is not affected by any Cost Index.

Capital Cost Trend

This is applied to the calibration value you set for Capital Cost in the Resource/Costs dialog.

Default: Constant {1.0}.

Charge Multiplier

The margin applied to a Service’s cost per connection, fed back from the previous year, in order to calculate the cost-dependent tariff for the current year. For example, a value of 1.2 would represent a 20% margin for the cost-dependent tariff.

Default: Constant {1.0}. No margin is applied.

Churn Cost

The cost of churn per unit of a Resource in the Calibration Period, if the Churn Mode is Normal or Inflate Demand. It is not recommended to use this input when the Churn Mode is Inflate Operations Costs, as the cost of churn is then modelled through the Operations Cost.

Default: 0.0.

Churn Cost Trend

This is applied to the calibration value you set for Resource Churn Cost in the Resource/Costs dialog.

Default: Constant {1.0}.

Churn Mode (1)

A choice of the way in which the costs of a resource are affected by churn:

Normal: a Churn Cost is generated for the Used Capacity of the resource, in proportion to the effective Churn Proportions of services and transformations using it.

Inflate Operations Cost: the Operations Cost for the resource is increased by the effective Churn Proportions of services and transformations using it. This is an alternative way to model the cost of churn.

Inflate Demand: demand for the resource is increased by the effective Churn Proportions of services and transformations using it (without affecting the Demand or Output of those services or transformations).

Note: Churn will only be modelled if the Churn Proportion is set to a number greater than 0.0 in the Service / Other Details dialog.

Default: Normal.

Churn Proportion (1)

The proportion of connections to a service which are disconnected and reconnected annually.

Churn in demand has no direct impact on the Resources installed in the network, other than to generate additional costs, except for Resources whose Churn Mode is Inflate Demand. Supply-side churn is driven by Resource Requirement Churn Proportions.

Default: Constant {0.0}. There is no Service demand churn.

Churn Proportion (2)

A proportion of the demand from a Service or Transformation using a particular Resource, which is re-allocated each year as incremental demand, according to the current proportions in the Requirements dialog.

This mechanism can accelerate the introduction of new Resources into a model, since demand is transferred to a new Resource before the original Resource reaches the end of its physical lifetime. The Redundant Unit Decommissioning Proportion then allows you to model early decommissioning of redundant Resources.

Default: Constant {0.0}. Each unit of demand continues to use the Resource to which it is initially assigned.

Churn Resources

A choice of whether the effective Churn Proportion for a Transformation is passed onto the Resource Requirements for that Transformation.

No: the capacity of Resources used by the Transformation is not churned.

Yes: the effective Churn Proportion is applied to the capacity of Resources used by the Transformation.

Default: No.

Churn Tariff

The one-off tariff charged per churned connection. For example, a Service with a Churn Proportion of 0.5 receives the Churn Tariff from 50% of its customers.

Default: Constant {0.0}.

Column

You may optionally specify a number like 1, 2 or 3 for anonymous columns, or strings like Column 1, Column 2 or Column 3 for columns with headings.

See 8.2.4 Export of selected inputs from the STEM model editor for further details.

Connection Cost

The one-off non-capitalised cost of leasing a unit of a Resource in the Calibration Period, e.g., the connection cost of a leased line.

Default: 0.0.

Connection Cost Trend

This is applied to the calibration value you set for each Connection in the Resource/Costs dialog.

Default: Constant {1.0}.

Connection Tariff

The one-off tariff charged per new connection to a Service.

Default: cost independent and Constant {0.0}.

Note: The simple Tariffs dialog just shows the Cost Independent Tariffs, which are also shown in the more detailed Cost Dependent Tariffs dialog.

Connections Unit

The unit of connections, e.g., Customers, Establishments, Homes. Either type a unit or choose from the drop-down list.

The selection has no mathematical effect on the model but the text is used to label the y-axis on results graphs.

Default: none.

Constant

The value which defines the value of the time series for every year of the model run.

Default: varies by input.

Constrain

A choice of whether the calculated value of a straight line time-series may be lower than a non-negative Base value prior to the Base Period if the Increment is positive (or after the Base Period if the Increment is negative). If the Base value is strictly negative, then this choice governs whether, in either case, the output may exceed this Base value and approach zero.

Yes: the output value is constant prior to the Base Period if the Increment is positive (or after the Base Period if the Increment is negative; or vice versa if the Base value is strictly negative). This option provides a simple way to avoids troublesome negative values.

No: the output is not constrained and maintains a consistent Increment either side of the Base Period.

Default: Yes.

Contention Ratio

For a data service, the ratio of the theoretical maximum demand to the demand that can be met by the network. For a voice service (i.e., with Traffic Calculation set to Volume Driven) this input is ignored.

Default: Constant {10.00}. Assumes that the network is dimensioned to meet one tenth of the theoretical maximum demand if all users required the service simultaneously.

Control

Specifies the type of control used for a field in the web presentation.

See 8.2.4 Export of selected inputs from the STEM model editor for further details.

Cost Allocation

The proportions of each of the various individual costs which should be recovered from the three main tariffs, when cost-dependent tariffs are used. For each cost, there is one proportion for each of the Connection, Rental and Usage Tariffs. These proportions must be between zero and one, and must sum to one, so that the entire cost can be recovered.

Service Administration and Provision Costs can be apportioned for each individual Service.

Resource Depreciation, Amortisation and Maintenance, Churn, Connection, Rental, Usage and Operations Costs are apportioned identically for each Resource in a Function. These proportions govern the way that the shares of these costs, allocated to each Service using a Resource, are split between those Services’ tariffs.

Default: each cost is recovered wholly from one kind of tariff:

Service Provision Costs, and Resource Churn and Connection Costs from Connection Tariffs.

Service Administration Costs, and Resource Depreciation, Amortisation and Rental Costs from Rental Tariffs.

Resource Maintenance, Usage and Operations Costs from Usage Tariffs.

Resource Decommissioning Costs are split between tariffs in the same proportions as Connection Cost.

Cost Breakdown (1)

A choice of whether STEM generates the Service allocated cost results broken down by individual contributing Resources.

None: allocated cost results are not broken down by individual Resources.

Opaque: allocated cost results are limited to a single layer of the network. In this mode, an intermediate Service presents a sub-total of all costs allocated from any secondary layers.

Transparent: allocated cost results are stored for all Resources that contribute costs to a given Service.

Default: None.

Cost Breakdown (2)

A choice of whether STEM stores the Service allocated cost results broken down by individual contributing Resources.

No: allocated cost results are not stored for this element. If a Service is excluded, no allocations will be available for that Service. If a Resource is excluded, its contribution to any given Service allocation will be hidden.

Yes: allocated cost results are stored.

Default: Yes.

Cost Independent Tariff

The cost-independent part of a composite tariff, the latter of which is calculated as a weighted average of the cost-independent and cost-dependent tariffs, according to the Independence Weighting.

Default: Constant {0.0}.

Note: The simple Tariffs dialog just shows the Cost Independent Tariffs, which are also shown in the more detailed Cost Dependent Tariffs dialog.

Cost Index Proportion

The proportion of the Capital Cost of a Resource associated with a given Cost Index in the Calibration Period. The set of proportions for all Cost Indices must sum to one (or zero).

The Capital Cost of each new unit of Resource, in years other than the Calibration Period, is based on the cost of the Resource in the Calibration Period, modified in accordance with its Capital Cost Structure and the Cost Index Cost Trends.

Default: 0.0. The unit Capital Cost is not affected by this Cost Index.

Cost Period

Defines a reference period for recurring cost inputs such as Maintenance Cost, Administration Cost or Operations Cost (which are interpreted as cost per cost period, such as EUR per month or USD per annum). This indicates how the cost input should then be scaled in proportion to the length of the current period for calculation.

Default: Year.

Cost Trend

A time series representing the relative development of a cost throughout the model run. A cost is specified for a Service or Resource Calibration Period; its value for other years is then calculated by multiplying the calibration cost by the normalised Cost Trend, i.e., the Cost Trend divided by its calibration-year value.

As an alternative to using Cost Trends, it is possible to define Resource costs as time series in their own right for individual Resources.

The Cost Trends for Capital, Maintenance, Churn, Decommissioning, Connection, Rental, Usage and Operations Cost may be defined both globally and for each individual Resource. The effective trend for each Resource is the product of these two trends, and these costs are further modified by individual Resource Age Factors for each cost.

Capital Costs may be modelled in more detail with reference to various Cost Index Cost Trends (as well as Economies of Scale).

Default: Constant {1.0}.

Costs

If defined, this input of a Previous or Time Lag transformation is used as an alternative target for cost-allocation in order to avoid the circularity which would otherwise arise if the transformation were used to calculate a difference equation indirectly involving ‘itself’ (i.e., an earlier value of the same transformation).

Default: Resource (<none>, Installed Capacity).

Current Year Dividend Proportion

The proportion of declared dividends which should be paid as interim dividends in the current year.

Default: Constant {0.0}. Dividends are paid wholly in the following year.

Current Year Tax Proportion

The proportion of tax charged which should be paid in the current year.

Default: Constant {0.0}. Tax is paid wholly in the following year.

Customer Base

The number of potential customers for a Service, e.g., the total number of businesses, the number of small, medium or large businesses or the adult population of an area.

The Customer Base for a Service can be defined directly as a time series, or as a reference to a separate Market Segment or Transformation element.

Default: Constant {0.0}.

 

       Buy SSL

© Implied Logic Limited