Lam Cao | University of Wollongong (original) (raw)

Papers by Lam Cao

Modelling and data frameworks for understanding infrastructure systems throuh a systems-of-system... more Modelling and data frameworks for understanding infrastructure systems throuh a systems-of-systems lens

TransMob: an agent based simulation of transport demand and residential mobility in South East

International Symposium for Next Generation Infrastructure Conference Proceedings, 2015

Agent based modelling has emerged as a promising tool to provide planners with insights on social... more Agent based modelling has emerged as a promising tool to provide planners with insights on social behaviour and the interdependencies characterising urban system, particularly with respect to transport and infrastructure planning. This paper presents an agent based model for the simulation of land use and transport demand of an urban area of Sydney, Australia. Each individual in the model has a travel diary which comprises a sequence of trips the person makes in a representative day as well as trip attributes such as travel mode, trip purpose, and departure time. Individuals are associated with each other by their household relationship, which helps define the interdependencies of their travel diary and constrains their mode choice. This allows the model to not only realistically reproduce how the current population uses existing transport infrastructure but more importantly provide comprehensive insight into future transport demands. The router of the traffic micro-simulator TRANSIMS is incorporated in the model to inform the actual travel time of each trip and changes of traffic density on the road network. Simulation results show very good agreement with survey data in terms of the distribution of trips done by transport modes and by trip purposes, as well as the traffic density along the main road in the study area.

International Journal of Microsimulation

Illicit heroin use is a worldwide problem, with significant health and social costs. Treatment is... more Illicit heroin use is a worldwide problem, with significant health and social costs. Treatment is known to be effective in changing heroin use habits, but it often needs to be provided over a lifetime, with people cycling in and out of treatment. It is therefore important to

INCOSE International Symposium

Drug and Alcohol Dependence, 2017

ECMS 2016 Proceedings edited by Thorsten Claus, Frank Herrmann, Michael Manitz, Oliver Rose, 2016

Illicit drug use creates significant burden at societal, family and personal levels. Every year s... more Illicit drug use creates significant burden at societal, family and personal levels. Every year substantial resources are allocated for treatment and the consequences of illicit drug use in Australia and around the world. Heroin is one of the major forms of illicit drugs. Several independent heroin treatment strategies or interventions exist and state-of-the art research demonstrates their efficacy and relative costeffectiveness. However, assessing total potential gains and burden from providing all treatment interventions or varying the mix of heroin treatments has never been attempted. This paper proposed an individual-level simulation model (ISM) which addresses net social benefit over a lifetime that can accommodate the complexity of individuals going in and out of multiple treatments and their corresponding costs and benefits arising from different treatments during the life-course of heroin users in the context of New South Wales (NSW) Australia. This model is intended to serve as an effective tool for economic evaluation and policy making in the illicit drug area in Australia. The validity of the model has been assessed by comparing short term outcomes or examining the status of participants at a various points of time predicted from the model with other data sets that were not used to parameterise the model. Initial model results have been also presented to highlight different types of scenario analysis that can be conducted in future.

Modelling and analysis of large systems of infrastructure systems carries with it a number of cha... more Modelling and analysis of large systems of infrastructure systems carries with it a number of challenges, in particular around the volume of data and the requisite complexity (and thus computing resources required) of models. In this paper we present an integrated land use-transportation model of a region in Sydney, and detail how we integrated an agent-based model of location and transport choice with a traffic micro-simulator. We also discuss both some novel architectures for scalability of modelling as well as for fusion and relevant visualisation of large data sets. We have a particular focus on geospatial infrastructure data visualisation.

ABSTRACT Agent based modelling has emerged as a promising tool to provide planners with sophistic... more ABSTRACT Agent based modelling has emerged as a promising tool to provide planners with sophisticated insights on social behaviour and the interdependencies characterising urban systems, particularly with respect to transport and land use planning. This paper presents an agent based simulation, called TransMob, of transport demand and residential mobility in South East Sydney, Australia. In this model, each agent represents an individual resident of the study area. Each agent is given an initial travel diary made of a sequence of daily activities (or trip purposes), associated travel modes and intended departure times. Agents are grouped in various types of household which generate social interdependencies and additional constrains on travel diaries. This initial synthetic population is then allowed to evolve for 20 years, driven by natural growth parameters, social bonding (marriage or divorce) and migration rates. A micro-simulation component calculates daily traffic conditions and individual travel times, allowing for multi-modal journeys. The transport mode choice component uses a multinomial logit model for individual decisions based on various fixed and variable costs as well as socio-economic characteristics. Residential mobility is simulated through a two-step process: first, deciding to move out; then, selecting a destination for relocation. The first step uses a multinomial logit model, while the second one uses a semi-empirical perceived liveability model to inform individual decisions. Simulation results show satisfactory agreement between simulated outputs, socio-demographic changes recorded by the Australian Census and transport patterns recorded by the Household Travel Survey for Sydney Metropolitan Area.

Proceedings of the International Symposium for Next Generation Infrastructure, 2014

This paper presents a methodology to construct travel related activity schedules for individuals ... more This paper presents a methodology to construct travel related activity schedules for individuals in a synthetic population. The resulting list of activity schedules are designed as an input into a micro-simulator for urban transport dynamics analysis. The methodology involves two main steps. The first step generates a synthetic population based on census data sourced from the Australian Bureau of Statistics (ABS). The second step assigns individuals in the synthetic population activity schedules using Household Travel Survey (HTS) data related to the geographical area of interest (in this case, the Sydney Greater Metropolitan area). Each individual is assigned an ordered set of trips, travel purpose, travel mode, departure time and estimated trip time. The significance of the methodology is twofold in that it generates a synthetic population aligned with area demographics, as well as generating activity schedules that realistically represent how the population uses existing transport infrastructure. The methodology also preserves the inter-dependencies (in terms of the sequence, travel times and purpose of trips) of individual's daily trips, in contrast to many trip generators for transport micro-simulation purposes. A case study of Randwick area in southern Sydney is presented where the proposed methodology is applied. Case study data is validated against real world results and the scalability and applicability to other urban areas are discussed.

a) , Van Hoang2 (b) , Marian Shahanan3 (b) , Alison Ritter4 (b) , Vu Lam Cao5 (a) , Pascal Perez6... more a) , Van Hoang2 (b) , Marian Shahanan3 (b) , Alison Ritter4 (b) , Vu Lam Cao5 (a) , Pascal Perez6 (a) (a) SMART ABSTRACT Illicit drug use has created an enormous burden at societal, family and personal levels. Every year a significant amount of resources is allocated for treatment and the consequences of illicit drug use in Australia and around the world. Heroin is one of the major forms of illicit drugs that are used illegally. Several independent heroin treatment strategies or interventions exist and state-of-the-art research demonstrates their efficacy and relative cost-effectiveness. However, assessing total potential gains and burden from providing all treatment interventions or varying the mix of heroin treatments has never been attempted. Furthermore, the need to include multiple treatments, multiple important outcomes, and the chaotic nature of drug dependence means cost-effectiveness studies are not able to provide evidence on net benefit of providing heroin treatments over...