Re: [UrbanSim-Users] Household location choice estimation

Thanks Hana, that does clear up some confusion. I have a couple
follow-up questions. First, I still don't understand why the
households_for_estimation and households tables are internally attached.
Are the tables being joined or appended? I see where you distinguish
between the agent_set and agents_for_estimation_table_name in
urbansim/configurations/household_location_choice_model_configuration_creator.py,
but am still puzzled about why the tables need to be attached. Also, if
I include the attribute INCOME (or AGE_OF_HEAD, PERSONS, etc) as
urbansim.household.income in the HLCM specification, is that referring
only to the data from the households_for_estimation table? Finally,
although you suggested making changes directly to
household_location_choice_model_configuration_creator.py, I'm wondering
if there is a way that I can pass these arguments in a configuration
file (so that I don't mess up the source code). Thanks again for your help,
brian

Hana Sevcikova wrote:
> Brian,
>
>
>> Perhaps I am confused about the function of the estimation procedure. I
>> understand that the number of movers and the unplaced agents are derived
>> by the Household Relocation Model, but how do these movers and unplaced
>> agents relate to the records in the households_for_estimation table?
>> More specifically, how can there be more movers / unplaced agents than
>> there are records in the households_for_estimation table?
>>
>
> In the default estimation behavior we try to create the same situation
> as in the simulation of HLCM which runs in 12 chunks (corresponding to
> 12 months). So we let the HRM choose movers (from the whole household
> set) and unplace 1/12 of them (randomly chosen), in order to have
> similar vacancy as in the simulation. Households in
> households_for_estimation are unplaced too, but after the their location
> is captured and passed to the estimation procedure. Note that the
> households_for_estimation table is by default internally attached to the
> households table, in order to have information about the whole population.
>
> As I said, this behavior is the default one and can be changed. You can
> look at
>
> urbansim/configurations/household_location_choice_model_configuration_creator.py
>
> I just added comments to the arguments (so please get the newest file
> from svn). You can then experiment with changing the default values here.
>
>
>> Perhaps too I
>> don't understand correctly what the dependent variable is that we are
>> modeling. I thought the estimation procedure evaluated the location
>> choice for each household in the household_for_estimation table compared
>> to the attributes of the other records in the choice set. Is this correct?
>>
>
> It is correct.
>
> I hope this clarifies it a little bit.
>
> Hana
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Received on Wed Mar 05 2008 - 12:35:43 PST