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OCR for page 193
182 I N N O VAT I O N S I N T R AV E L D E M A N D M O D E L I N G , V O L U M E 2
dom number series to determine which possibility is cho- Linux 32-bit OS
sen for that record. · Networking Specifications
The new model is implemented with three global feed- 5 port 10/100/1000 Gigabit network switch
back loops for consistency between highway travel times CAT6 Ethernet cable
that are both used as inputs to, and as forecast outputs
of, the model. The workers are directly networked and are isolated
The main model application package is Cube, with from the general MORPC network to make them less
TP+ being used for network management, assignment, susceptible to viruses. The workers are not running anti-
external, and commercial vehicle models and other pro- virus software every time a file is accessed, unlike the rest
cessing. The core tour-based choice models described of the MORPC network; it was found that running anti-
above are written in Java with access to the TP+ skims. virus software imposed a 15% penalty on the run time.
The custom programs are designed to take advantage of In December 2005, a fourth worker was added to the
the numerous opportunities for parallel processing in the cluster. This first system is running 32-bit OSs and Java.
model chain, multi-threading of tasks, and to readily The second system was purchased by the Central
accommodate the addition of computers in the distribu- Ohio Transit Authority (COTA) in support of its North
tive processing framework to optimize processing. Corridor Transit Project DEIS. This cluster consists of
After the networks and initial skims are generated in one server and four workers all running 64-bit Windows
TP+ and all input files are created for a particular sce- and Java. The specifications for this cluster are below.
nario, the custom Java programs are executed to imple-
ment the tour-based microsimulation models. A · Server
pre-assignment processor step aggregates the microsimu- Dual 64-bit AMD Opteron 2.2 GHz 1MB L2
lation results and integrates the commercial and external Cache Processors
models to produce standard TP+ trip tables for four time 4 GB PC3200 ECC Registered DDR Memory
periods. After the final trip tables are generated, vehicles 4 - 73GB SCSI U320 10K RPM RAID-5 Array
are assigned with a multi-class (SOV, HOV, medium Dual Gigabit network interface cards
truck, and heavy truck) equilibrium assignment utilizing Windows 2003 Server 64-bit OS
21 volume delay functions by facility and area type for · Worker (4)
each of four time periods (a.m., midday, p.m., and night). Dual 64-bit AMD Opteron 2.2 GHz 1MB L2
Transit assignments are also performed in TP+ for the Cache Processors
a.m. and midday time periods, with standard reports 4 GB PC3200 ECC Registered DDR Memory
generated to support analysis and evaluation of the alter- 160 GB SATA NCQ HDD
natives tested (Anderson et al. 2003). Dual Gigabit network interface card
Windows XP Professional 64-bit OS
HARDWARE CONFIGURATIONS
MODEL RUNNING TIMES
There are three operational systems that can run the
MORPC travel forecasting model. The two systems that Table 1 shows the running times of the MORPC Travel
are currently installed at MORPC are the topic of this Forecasting Model for 2000 and 2030 on the various
paper. The initial system was built in December 2004 computer systems. MORPC 3 is the MORPC system
with one server computer and three worker computers. with three Linux workers running 32-bit OSs, MORPC
The specifications for the computers are below. 4 is the MORPC system with four Linux Workers run-
ning 32-bit OSs, and COTA is the COTA system with
· Server four Windows XP Workers running 64-bit OSs. The
Dual 64-bit Xeon 3.6 GHz 1MB L2 800MHz 2000 model has 1.5 million synthetic people making 2
FSB Processors million tours; 2030 has 2 million synthetic people mak-
4 GB PC3200 ECC Registered DDR Memory ing 3 million tours. All runs include only two transit
4 - 36GB SCSI 15K U320 RAID-5 Array modes (local and express bus). The core model running
Dual Gigabit network interface cards time does not include the time to generate the four-period
Windows 2000 Server Operating System (OS) highway networks, two-period transit networks includ-
· Worker (34) ing support links, or the time to generate the initial travel
Dual Xeon 3.06 GHz 512KB L2 533MHz FSB skims, which is similar to the time to generate the travel
2 GB PC2100 ECC Registered DDR Memory skims during the model run. Overall, the time for these
120 GB IDE HDD excluded tasks is about 2 h of running time on a 32-bit
Gigabit network interface card Windows computer.
