Scenario Parameters in SIMTRAP
This document describes a part of the interface between
the SIMTRAP Server and the HPCN Model Server,
that runs both the traffic model DYNEMO and the air quality models
of the DYMOS system.
For the syntax of this interface and its implementation details,
please refer to the
SIMTRAP Architecture Description.
SUMMARY
The parameter set defining a useful decision alternative for
the user consists of several parts:
Explicit Parameters: these are directly accessible to the
user and can be edited; they may include selections from (sets of)
predefined data sets such as transportation networks or emission
inventories. They include:
- Meteorological parameters
- Emission parameters including background
concentrations and initial values;
- Traffic related data
Implicit Parameters: are stored primarily with the HPCN Model
Server and are not directly accessible to the user for editing.
They may be shown in the user interface to assist selection from
predefined read-only sets (e.g., a road network geometry), or be
completely transparent (e.g., internal model coefficients).
General Control Parameters: (not yet clarified, might depend on
performance) they would define model control parameters such as the
overall length of a simulation run (just a few hours around rush hour,
one or more days ?) as well as output frequencies.
Each model scenario contains a complete set of default parameter values;
upon entering the scenario selection/editing, there is always a (default)
scenario loaded. The user can, but does not have to, make any changes
(selection of alternative scenarios, changes to values within a scenario)
to the scenario specification as required. These can then be stored,
together with the model results, for later analysis or as the basis for
future modifications.
Meteorology
Data required:
Several data sets each consisting of time series for
- Wind Field (speed + direction) in different layers up
to at least 4000 m,
- Potential temperature in different layers (same as above),
- surface temperatures (soil, water)
- Cloud Cover
All data should be available as regular time series
at 6-hourly intervals, for at least one location representative for the
model domain.
Scenario Parameters Passed to Model Server
| Description |
Parameter |
Translates into |
| Meteorology Scenario |
scenario ID: string |
a complete data set
indexed by the ID,
stored at the Model server |
User Interface considerations
The SIMTRAP server has a list of admissible descriptive
meteorology scenario names with associated IDs (dates encoded:
YYYYMMDDHHMM representing the starting time of the scenario; absolute
dates use the YYYY encoding, synthetic dates use 0000
for the year) along with the following descriptors:
- starting date,
- average temperature (over time and space),
- average wind speed,
- average displacement (definition?),
- average cloud cover.
The user selects a scenario based on the scenario name (ID).
Alternatively, the user could specify values for any or all of the above
characteristics, and the the best fit scenario is retrieved.
The user acknowledges, and ID is passed to model server.
This requires, however, that either a large set of scenarios, or
continuous time series of at least one year of all the above parameters
are available at the SIMTRAP server. Please note that in this case, the
meteorological time series can also be displayed and analyzed with the
time series analysis tools of the ACA ToolKit
time series analysis functions.
Emission
Data required
Several data sets each consisting of time series for
- industrial emission matrices (NO, NO2, VOC),
- household emission matrices (NO, NO2, VOC),
- background concentrations (NO, NO2, VOC)
Scenario Parameters Passed to Model Server
| Description |
Parameters |
Translates into |
| Industrial Emissions |
ID: string (descriptive name)
scale factor: float |
time series of matrices indexed by ID, scaled by factor |
| Household Emissions |
ID: string
scale factor: float |
time series of matrices indexed by ID, scaled by factor |
| Background Concentrations |
ID: string
scale factor: float |
time series indexed by ID, scaled by factor |
Please note that for both emission parameters and background
concentration, three values for NO, NO2, and VOC have to
be specified in each case.
An unspecified values indicates the default, i.e.,
a multiplier of 1.0.
User Interface considerations
Selection of (matrix) time series: GMD must check whether more than one
(structurally different) base matrix for industries and households is necessary.
Road network
Data requirements
Nodes and links of the network together with VISUM and DYNEMO attributes
(not the trip matrix!).
Alternative road network scenarios represent different planning states,
e.g., with and without new planned roads implemented.
Scenario Parameters Passed to Model Server
| Description |
Parameters |
Translates into |
| Network Scenario |
ID: string |
a complete data set indexed by the ID |
User Interface considerations
List of IDs is sufficient, as number of alternative network
scenarios will in general be small.
Trip Matrix
Data requirements
- several trip matrices for different days of the week
- difference trip matrices that contain deltas between the trip
matrix for an average day and the one for a day
with a special event (e.g. football match).
time of the day???
Scenario Parameters Passed to Model Server
| Description |
Parameters |
Translates into |
| Day (of the week or special) |
ID: string |
a trip matrix indexed by the ID |
| Special Event (optional) |
ID: string
weight factor: float |
the difference trip matrix indexed by the ID is weighted
and added to the base trip matrix
|
User Interface considerations
IDs for day of week may also include special days
such as Bank Holiday.
Link Attributes
Data requirements
For each link:
- number of lanes,
- v-k relation
- desired speed distribution
Scenario Parameters Passed to Model Server
| Description |
Parameters |
Translates into |
| Link Closure (optional) |
link: linkID nodeID
from: integer to: integer |
link closure (directly supported in
DYNEMO *.DST input data), decision cross-sections
adjacent to closed link
|
| Link Closure for Vehicle Type (optional) |
link: linkID nodeID
vehType: integer
(no time window) |
link parameters (directly supported in DYNEMO *.DST input data)
Link Closure for Vehicle Type |
| All Links of Specified Type (optional) |
linkType: integer
vehType: integer
(no time window) |
link parameters (directly supported in
DYNEMO *.DST input data) |
| Fewer lanes (optional) |
link: linkID nodeID
lanes: integer (<= ORIG. NUMBER OF LANES) |
link parameters (directly supported in
DYNEMO *.DST input data) |
| Reduced Capacity (optional) |
link: linkID nodeID
percentage: integer from: integer to: integer |
vWunsch relation, v-k relation
|
| Speed Limit (optional) |
link: linkID nodeID
speed: integer [km/h] (no time window) |
vWunsch relation, v-k relation
|
| Speed Limit: All Links of Specified Type (optional) |
linkType: integer
speed: integer [km/h]
no time window! |
vWunsch relation, v-k relation
|
User Interface considerations
Links are addressed by a combination of the VISUM link number and the
VISUM node number of the source node (to indicate direction unambiguously)
Global Traffic Parameters
Data requirements
- trip matrix,
- fleet composition,
- specific events
- Scenario Parameters Passed to Model Server
| Description |
Parameters |
Translates into |
| Trip matrix scale factor (optional) |
factor: float |
multiply base matrix by factor |
| Fleet Composition Change (optional) |
vehType: integer
delta: +/- integer [%] |
change fraction of specified vehicle type
by percentage in all fleet compositions |
User Interface considerations
The scenario parameter has to be presented to the user in a problem context
rather than as a model parameter: instead of Trip Matrix Scaling
Factor, for example, the user defines an overall increase in
traffic volume.
SIMTRAP server translates any of these problem related specifications into
the appropriate combination of Link and Trip Link and Trip Matrix scenarios.
