I’ve implemented a procedure similar to yours for studying that classifies the connections of a network according to their importance in maintaining adequate connectivity between all the pairs origin-destination. The aim of the work was to answer the following question: which are the most critical links for a mountainous road network? The network model includes all roads except local roads and is composed of 1,607 nodes (of which 293 represent centroids, 726 junctions, and 588 represent a
change in the road geometric features) and 3,500 bi-directional links.
Going into more detail, link flows have been first simulated for the base scenario
(undamaged network) to calculate
total-trip cost for the undamaged network. The software then allowed me to re-run the assignment procedure, each time removing a bidirectional
link j, calculating link flows and total-trip cost for the damaged network; in
the case where the link j was a cut link, the software also provided the unassigned
demand. The specific link was not phisically removed but simply add to a Group excluded from essingment.
main steps of procedure:
- create a LOOP app
the loop variable name is id_loop and varies from 1 to the max link number (in my case 3500)
in the input network each link has been coded with an ID number and a field namend CLOSED1. ID number
and CLOSED1 must be the same wtin non interval between links.
- the highway script is the following and permit to close one link at time and assing:
UN PGM=HIGHWAY PRNFILE=“E:\lavori\2010\0310 - prov di bz\CUBE\BASE\EX_MULTI_ASSEGNAZIONE_DUE\DAM_TON\MAHWY00D.PRN” MSG=‘due Highway Assignment’
FILEI NETI = …RC_VUL.NET"
FILEI MATI = …\POST_STIMA_F_R1.MAT"
FILEO NETO = …DAM_DUE.NET"
FILEO MATO = …COST.MAT",
MO=1-3 NAME=COST_TOT TIME DISTANCE
PARAMETERS MAXITERS = 99 GAP=.00001
PARAMETERS COMBINE = EQUI, GAP = 0.001, maxiters=99
PARAMETERS COMBINE = EQUI, GAP = 0.01, maxiters=99
; USE THE USER SUPPLIED ALPHA AND BETA FOR THE BPR CURVE
If (LI.CLOSED1=@ID_LOOP@) ADDTOGROUP=1
PATHLOAD PATH = TIME VOL=MI.1.1, EXCLUDEGROUP=1, MW=PATHTRACE(TIME), MW=PATHTRACE(LI.DISTANCE), MW=MWMI.1.1
MW = MW
MW[I] = 0
MW[I] = 0
FUNCTION TC=T0(1+1((V/10)/©)^3) ; congested time equation
FUNCTION TC=T0(1+3((V/10)/©)^6) ; congested time equation
Matrix was used to calculate total_cost and demand not assigned for each assignement end write in record file
before the end of each loop, wrote the total_cost into and not assigned demand into a specific network field (network #5)
at the end of loop you will have 3500 network assignend and you can aggregate into one using
a new ILOOP procedure. Final network will be the first “undamaged” with 2 new field contaning total_cost and not assigned demand related to the specific link
i hope this cal help you, procedure is really complex but it vary fast and powerful. I have tryied with other software but only cube allows this approch. If you like
you can read results of my works here:
The Evaluation of Road Network Vulnerability in Mountainous Areas: A Case Study
Federico Rupi, Silvia Bernardi, Guido Rossi & Antonio Danesi
Networks and Spatial Economics A Journal of Infrastructure Modeling and Computation