Customized Simulation Modeling Using PARAMICS Application Programming Interface
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Customized Simulation Modeling Using PARAMICS Application Programming Interface Henry Liu, Lianyu Chu & Will Recker
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Customized Simulation Modeling Using PARAMICS Application Programming Interface. Henry Liu, Lianyu Chu & Will Recker. Overview. Introduction Why Customize? PARAMICS API Development Plug-ins Developed Wrap-up. User. Input Interface. Professional Community Oversight. - PowerPoint PPT Presentation
Transcript of Customized Simulation Modeling Using PARAMICS Application Programming Interface
Customized Simulation Modeling Using PARAMICS Application Programming Interface
Henry Liu, Lianyu Chu & Will Recker
Overview
• Introduction
• Why Customize?
• PARAMICS API Development
• Plug-ins Developed
• Wrap-up
User
Developer
Output Interface
Input Interface
GUI Tools
Professional Community Oversight
Core Model API
Introduction
Introduction (Contd.)
API provides users with a functional interface
Command-based
With GUI
With API
Data Interface
Functional Interface
Simulation Program
Introduction (Contd.)
function calls:vehicle related..
link related..and others
user-definedprograms
Main simulation loop PluginsAPI
data
Other applications
/APIs
Role of a typical API
functions
Introduction (Contd.)
CustomizationCustomization
pushing the limitspushing the limits
More on the API…
Plug-and-play environmentPlug-and-play environment
reusable and generic pluginsreusable and generic plugins
API: the “soft key” to the black-box API: the “soft key” to the black-box
Why Customize?
Incident Detection
Intelligent Parking
Travel Time Prediction
Signal Control Systems
Transit Priority
Electronic Road Pricing
Road Maintenance Scheduling & Monitoring
Bus Scheduling Assistance
TESTBED
Why Customize? (Contd.)
Network Building
Performance Measurement
Additional Functionality: ITS Elements
Basic Functionality: signals etc
Customize
PARAMICS API
Simulation Loop
Overload Functions
Override Functions
Callback Functions
Built-in Functions
Built-in Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
User Functions
PARAMICS API (Contd.)
Access via API
At every timestep (or at intervals)
When an event occurs in simulation
Event triggered by user
PARAMICS API Development
A Hierarchical Approach
Provided API Library
ATMIS Modules
Developed API Library
Advanced Algorithms
Data Handling
Routing
Ramp
Signal
CORBA
Databases
Adaptive Signal Control
Adaptive Ramp Metering
Dynamic Network Loading
Demand
XML
Developed Basic API Library
• Path-based Routing (Para-Dyn)
• Paramics-CORBA Communication
• Actuated Signal Controller
• Time-based Ramp Metering
• Paramics-MySQL Communication
• Loop Aggregator
• Performance Measurement
Modules Developed
Actuated Signal Control Plugin
Inputs: Signal Timing Plan, including phase sequence, initial green, maximum green, unit extension time and system recall phase, etc. Detectors need to be specified and associated with movements to be activated.
• Standard During-ring Logic
• Actuated Signal Coordination
• Interface with some other signal optimization packages such as Transyt7F and SYNCHRO, etc.
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Approach 1
Approach 3
Approach 2
Approach 4
NEMA Phase
Detector
Detector number
Modules Developed
Ramp Metering
• Basic Time-based Module:
Input: time-of-day ramp control plan such as 6-9 AM, cycle length 5 sec.
Logic: n-cars-per-green
• Advanced Modules:
• Demand-capacity strategy
• Percent-occupancy strategy
• ALINEA
• BOTTLENECK
• ZONE
dete
ctor
Stop Lane
Mainline Traffic
Utility Plugins Developed
Paramics-MySQL Communication
Connecting PARAMICS simulation environment with MYSQL database
Includes a set of simple C routines programmed in MYSQL API functions.
The MYSQL database can be used in the following two folds:
• API users can store the simulation outputs to database;
• During a simulation process, MYSQL database can be used for storing intermediate simulation results, such as aggregated loop data, which can be queried by other external API modules at any time.
Utility Plugins Developed
Loop Aggregator
Input: time interval, smooth factor, detector name
Output: MYSQL database or ASCII file
volume, percent occupancy, speed, flow, headway
Performance Measurement Plugin
Utility Plugins Developed
To customize performance measurement for run-time interfacing with other tools such as data mining and signal optimization.
MOE: vehicle count, travel time, stopped time, vehicle-spent time in a specific speed range, turn counts from intersections, cycle time, individual phase time etc.
Data collected at a detector, node, link, corridor, OD pair or network levels, at specified time intervals, for specific type of vehicles where applicable.
Output can be in the form of a spreadsheet, text file or on-screen reporting.
Wrap up
1. While GUI helps in building a basic simulation network, API helps in customization of various functional aspects of simulation modeling.
2. Plugins provide users with more freedom to interrupt and control simulation processes and hence facilitates overcoming some of the challenges faced in modeling traffic scenarios of the ITS era.
Publications
1. Liu, X., Chu, L., and Recker, W., “Paramics API Design Document for Actuated Signal, Signal Coordination and Ramp Control”, California PATH Working Paper, UCB-ITS-PWP-2001-11, University of California at Berkeley, 2001.
2. Chu, L., Liu, X., Recker, W., and Zhang, H. M., “Development of A Simulation Laboratory for Evaluating Ramp Metering Algorithms”, Accepted for the presentation at TRB 2002.
