• Home
  • UNSW Sydney
  • School of Civil and Environmental Engineering
  • Lauren M. Gardner
Lauren M. Gardner

Lauren M. Gardner
UNSW Sydney | UNSW · School of Civil and Environmental Engineering

PhD in Civil Engineering

About

86
Publications
13,440
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,186
Citations
Citations since 2017
49 Research Items
960 Citations
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200

Publications

Publications (86)
Article
Full-text available
SARS-CoV-2 variants shaped the second year of the COVID-19 pandemic and the discourse around effective control measures. Evaluating the threat posed by a new variant is essential for adapting response efforts when community transmission is detected. In this study, we compare the dynamics of two variants, Alpha and Iota, by integrating genomic surve...
Preprint
Full-text available
Emerging SARS-CoV-2 variants have shaped the second year of the COVID-19 pandemic and the public health discourse around effective control measures. Evaluating the public health threat posed by a new variant is essential for appropriately adapting response efforts when community transmission is detected. However, this assessment requires that a tru...
Article
The emergence of the COVID-19 epidemic in the United States (U.S.) went largely undetected due to inadequate testing. New Orleans experienced one of the earliest and fastest accelerating outbreaks, coinciding with Mardi Gras. To gain insight into the emergence of SARS-CoV-2 in the U.S. and how large-scale events accelerate transmission, we sequence...
Article
Full-text available
The spread of traffic jams in urban networks has long been viewed as a complex spatio-temporal phenomenon that often requires computationally intensive microscopic models for analysis purposes. In this study, we present a framework to describe the dynamics of congestion propagation and dissipation of traffic in cities using a simple contagion proce...
Preprint
Full-text available
The recent outbreak of a novel coronavirus and its rapid spread underlines the importance of understanding human mobility. Enclosed spaces, such as public transport vehicles (e.g. buses and trains), offer a suitable environment for infections to spread widely and quickly. Investigating the movement patterns and the physical encounters of individual...
Preprint
Outbreaks of infectious diseases present a global threat to human health and are considered a major health-care challenge. One major driver for the rapid spatial spread of diseases is human mobility. In particular, the travel patterns of individuals determine their spreading potential to a great extent. These travel behaviors can be captured and mo...
Article
Full-text available
With approximately half of the world’s population at risk of contracting dengue, this mosquito-borne disease is of global concern. International travellers significantly contribute to dengue’s rapid and large-scale spread by importing the disease from endemic into non-endemic countries. To prevent future outbreaks and dengue from establishing in no...
Article
Full-text available
Background: In 2015, the Zika virus spread from Brazil throughout the Americas, posing an unprecedented challenge to the public health community. During the epidemic, international public health officials lacked reliable predictions of the outbreak's expected geographic scale and prevalence of cases, and were therefore unable to plan and allocate...
Article
The Zika epidemic in the Americas has challenged surveillance and control. As the epidemic appears to be waning, it is unclear whether transmission is still ongoing, which is exacerbated by discrepancies in reporting. To uncover locations with lingering outbreaks, we investigated travel-associated Zika cases to identify transmission not captured by...
Preprint
The spread of traffic jams in urban networks has long been viewed as a complex spatio-temporal phenomenon that often requires computationally intensive microscopic models for analysis purposes. In this study, we present a framework to describe the dynamics of congestion propagation and dissipation of traffic in cities using a simple contagion proce...
Preprint
Full-text available
The introduction and spread of emerging infectious diseases is increasing in both prevalence and scale. Whether naturally, accidentally or maliciously introduced, the substantial uncertainty surrounding the emergence of novel viruses, specifically where they may come from and how they will spread, demands robust and quantifiably validated outbreak...
Article
Full-text available
Travel demand modelling has a long history going back to 50s when the conventional four-step modelling structure was introduced and developed for Chicago and Detroit, USA. However, the first travel demand models for freight movements were not developed until 40 years after the first model for passenger cars. Freight models are yet limited to studie...
Preprint
Full-text available
With approximately half of the world's population at risk of contracting dengue, this mosquito-borne disease is of global concern. International travellers significantly contribute to dengue's rapid and large-scale spread by importing the disease from endemic into non-endemic countries. To prevent future outbreaks, knowledge about the arrival time...
Article
A critical issue in origin-destination (O-D) demand estimation is under-determination: the number of O-D pairs to be estimated is often much greater than the number of monitored links. In real world, some centroids tend to be more popular than others, and only few trips are made for intro-zonal travel. Consequently, a large portion of trips will be...
Article
Full-text available
Background An unprecedented Zika virus epidemic occurred in the Americas during 2015-2016. The size of the epidemic in conjunction with newly recognized health risks associated with the virus attracted significant attention across the research community. Our study complements several recent studies which have mapped epidemiological elements of Zika...
Data
The excel file includes the following input data and model results a) Regional population density, GDP and monthly reported case data used as input in the model; b) Monthly Case data for each country; c) The top 100 routes likely to result in local Zika transmission at the destination and their time-dependent relative risk estimates; d) The complet...
Article
Full-text available
Modern public transport networks provide an efficient medium for the spread of infectious diseases within a region. The ability to identify components of the public transit system most likely to be carrying infected individuals during an outbreak is critical for public health authorities to be able to plan for outbreaks, and control their spread. I...
Article
This article proposes a novel methodology that uses the bi-level programming formulation to calibrate the expected total demand and the corresponding demand variability of traffic networks. In the bi-level formulation the upper-level is either a new maximum likelihood estimation method or a least squares method and the lower-level is the strategic...
Article
This article proposes an extension of the strategic user equilibrium proposed by Waller and colleagues and Dixit and colleagues. The proposed model relaxes the assumption of proportional Origin-Destination (O-D) demand, as it accounts for users’ strategic link choice under independently distributed O-D demands. The convexity of the mathematical for...
Article
Full-text available
Modeling the spread of infections on networks is a well-studied and important field of research. Most infection and diffusion models require a real value or probability on the edges of the network as an input, but this is rarely available in real-life applications. Our goal in this paper is to develop a general framework for this task. The general...
Article
Full-text available
Infectious disease dynamic modeling can support outbreak emergency responses. We conducted a workshop to canvas the needs of stakeholders in Australia for practical, real-time modeling tools for infectious disease emergencies. The workshop was attended by 29 participants who represented government, defense, general practice, and academia stakeholde...
Article
Full-text available
[This corrects the article DOI: 10.1371/journal.pone.0174980.].
Article
Full-text available
Background Zoonotic avian influenza poses a major risk to China, and other parts of the world. H5N1 has remained endemic in China and globally for nearly two decades, and in 2013, a novel zoonotic influenza A subtype H7N9 emerged in China. This study aimed to improve upon our current understanding of the spreading mechanisms of H7N9 and H5N1 by gen...
Data
Risk analysis variables. Top row ckvalues at cells enclosing H5N1 and H7N9 exact points; bottom row hkvalues at cells enclosing H5N1 and H7N9 exact points. (TIF)
Data
Species distribution models 1–2. The first panel shows H5N1 (SDM 1) and the second panel shows H7N9 (SDM 2). Suitability values for each cell (approximately 1km2) are represented on a continuous scale of low (light grey) to high (dark grey). SDMs were built using Maxent software version 3.3.3k (available from https://www.cs.princeton.edu/~schapire/...
Data
Species distribution models 5–6. The first panel shows H5N1 (SDM 5) and the second panel shows H7N9 (SDM 6). Suitability values for each cell (approximately 1km2) are represented on a continuous scale of low (light grey) to high (dark grey). SDMs were built using Maxent software version 3.3.3k (available from https://www.cs.princeton.edu/~schapire/...
Data
Risk model validation for all cases using aggregated relative risk values. Number of all (unexact and exact) points per risk category (low 0.0–0.25; low-medium 0.25–0.50; medium-high 0.50–0.75; high 0.75–1.00). For each point, the maximum 1km cell relative risk value within approximately 5km radius was taken as the aggregated relative risk value. (...
Data
Exact H5N1 cases: spatial distribution in China. First panel indicates distribution by year, middle panel indicates distribution by type of host, last panel indicates type of location. Chinese provinces are outlined in grey. Data sources used to obtain the case locations include: the Food and Agricultural Organization (FAO) (http://empres-i.fao.org...
Data
Summary of variables used in risk analysis. (DOCX)
Data
Data set of exact H5N1 case locations. Each entry represents a case location which we considered an ‘exact’ case location. For each entry, we provide the source of information, and information associated with the case e.g. latitude and longitude coordinates, date associated with poultry outbreak or human case, the host species associated with the s...
Data
Summary of H5N1 exact locations. (DOCX)
Data
Exact H7N9 cases: spatial distribution in China. First panel indicates distribution by year, middle panel indicates distribution by type of host, last panel indicates type of location. Chinese provinces are outlined in grey. Data sources used to obtain the case locations include: the Food and Agricultural Organization (FAO) (http://empres-i.fao.org...
Data
Sub-selection of provinces for species distribution models 5–8. Map showing the 22 (of 31) primary administrative regions (provinces, municipalities, autonomous regions) selected as the study area in constructing SDM 5–8 (in grey). Base maps were obtained from the GADM database of Global Administrative Areas (http://www.gadm.org/). Maps were built...
Data
Species distribution models 7–8. The first panel shows H5N1 (SDM 7) and the second panel shows H7N9 (SDM 8). Suitability values for each cell (approximately 1km2) are represented on a continuous scale of low (light grey) to high (dark grey). SDMs were built using Maxent software version 3.3.3k (available from https://www.cs.princeton.edu/~schapire/...
Data
Data set of exact H7N9 case locations. Each entry represents a case location which we considered an ‘exact’ case location. For each entry, we provide the source of information, and information associated with the case e.g. latitude and longitude coordinates, date associated with poultry outbreak or human case, the host species associated with the s...
Data
Summary of H7N9 exact locations. (DOCX)
Article
Full-text available
Background: The 2015-16 Zika virus pandemic originating in Latin America led to predictions of a catastrophic global spread of the disease. Since the current outbreak began in Brazil in May 2015 local transmission of Zika has been reported in over 60 countries and territories, with over 750 thousand confirmed and suspected cases. As a result of it...
Data
Top 100 High Risk Travel Routes under Scenario D. (PDF)
Data
Top 100 Destination Cities at Risk under all Scenarios. (PDF)
Data
Top 29 Countries identified at greatest risk by each scenario based on outbreak status as of February 15, 2016. (PDF)
Data
Top 100 Origin Cities Posing Risk under all Scenarios. (PDF)
Data
Top 100 High Risk Travel Routes under Scenario A. (PDF)
Data
Set of Countries with local Zika transmission confirmed between February 15 and October 5 and relative ranking by Scenario. (PDF)
Conference Paper
Identifying components of the public transit system most likely to exacerbate disease spread is critical for public health authorities to be able to plan for epidemics and control their spread. In this work we propose a method to detect such components in a transit network using a three-stage approach. We first use results from a transit simulation...
Article
High volumes of passenger air travel increase the risk of infectious disease epidemics and pandemics. Regional preparedness planning for large-scale outbreaks requires models that are able to capture outbreak dynamics within a control policy evaluation framework. Previous studies focused on either modeling outbreak dynamics or optimizing outbreak c...
Article
Full-text available
Zika virus in Pakistan: the tip of the iceberg?
Article
To exploit the potential of electric vehicles (EVs) as a sustainable form of transport, the technology must be integrated into the traditional transport planning process. EV energy consumption will also become an essential issue for regional energy providers who will need to adapt to the additional electricity demand created by EVs. This study pres...
Article
Full-text available
The Zika virus is vectored by mosquito species of the genus Aedes, particularly the yellow fever mosquito, Aedes aegypti and, very likely, the Asian tiger mosquito, Ae. albopictus. These species also vector a host of other viral diseases including dengue and chikungunya all of which are “neglected tropical diseases” (NTDs) because of the lack of at...
Article
Preliminary evidence suggests that direct poultry contact may play a lesser role in transmission of avian influenza A(H7N9) than A(H5N1) to humans. To better understand differences in risk factors, we quantified the degree of poultry contact reported by H5N1 and H7N9 World Health Organization-confirmed cases. We used publicly available data to clas...
Article
Background Middle East respiratory syndrome coronavirus (MERS-CoV) emerged from the Kingdom of Saudi Arabia (KSA) in 2012 and has since spread to 26 countries. All cases reported so far have either been in the Middle East or linked to the region through passenger air travel, with the largest outbreak outside KSA occurring in South Korea. Further in...
Article
This study combines novel multibeam electron microscopy with a geographical information system approach to create a first, seamless, navigable anatomic map of the human hip and its cellular inhabitants. Using spatial information acquired by localizing relevant map landmarks (e.g. cells, blood vessels), network modeling will enable disease epidemiol...
Article
1 recently pointed out that Zika virus has been collected from several mosquito species including those from the genera, Anopheles, Culex, and Mansonia besides Aedes. Moreover, at least ten Aedes species are known to harbour Zika virus. However, the presence of the virus does not automatically make the species an effi cient vector for the disease....
Article
Full-text available
Obesity and other chronic diseases are becoming more prevalent in affluent countries such as Australia. Researchers are trying to understand and combat this trend. One related growing stream of research explores the role of the built environment and transport system on an individual's weight. However, results from many studies conducted have been c...
Article
An understanding is needed of how epidemics spread to new regions via the global air traffic network so that effective strategies for outbreak control can be developed. Various studies have focused on predicting epidemic spread via the complex air traffic network. However, there is a gap in the literature demanding real-time predictive models that...
Data
The Technical Appendix describes materials and methods used in the study of outbreaks caused by highly pathogenic influenza (HPAI) virus, subtype H5, in North America
Article
Full-text available
Ramp metering is a control technology used to manage the flow of traffic entering motorways and freeways, with the primary aim of minimizing congestion on the main thoroughfare. This technique has been studied and implemented globally since the 1960s. It has been shown that ramp meters improve the overall efficiency of the system; however, the dist...
Article
Full-text available
This paper presents an evaluation framework for high-occupancy/toll (HOT) lanes, extending previous frameworks by incorporat- ing departure time choice alongside stochasticity in demand. Drivers are divided into two classes, strategic and captive drivers. Strategic drivers time their departures to minimize expected generalized cost and can choose e...
Article
Epidemics of dengue fever occur every 3 to 4 years in the Philippines. The risk of a dengue fever outbreak in the Philippines has been heightened since Typhoon Haiyan struck the region in November 2013 because recovery efforts have been slow to progress. The structural damage caused by the typhoon resulted in an abundance of standing water, which c...
Article
Full-text available
Real-time control of infectious disease outbreaks represents one of the greatest epidemiological challenges currently faced. In this paper we address the problem of identifying contagion patterns responsible for the spread of a disease in a network, which can be applied in real-time to evaluate an ongoing outbreak. We focus on the scenario where li...
Article
Full-text available
The aim of this work was to explore the comparative epidemiology of influenza viruses, H5N1 and H7N9, in both bird and human populations. Specifically, the article examines similarities and differences between the two viruses in their genetic characteristics, distribution patterns in human and bird populations and postulated mechanisms of global sp...
Article
High-occupancy toll (HOT) lanes have become an increasingly prevalent form of congestion management pricing in the United States in the past few decades. The success of a HOT facility depends on the pricing scheme, which determines the utilization of the HOT lane, and the corresponding congestion relief on the parallel general purpose lanes. An add...
Article
Transport network pricing schemes are an integral traffic management strategy that can be implemented to reduce congestion, among other network impacts. However, the problem of determining tolls becomes much more complex when multiple sources of demand uncertainty are considered. This paper proposes a novel tolling model based on a particular varia...
Article
The spread of infectious disease is an inherently stochastic process. As such, real-time control and prediction methods present a significant challenge. For diseases that spread through direct human interaction, the contagion process can be modeled on a social contact network where individuals are represented as nodes, and contact between individua...
Article
Full-text available
Between April 2012 and June 2014, 820 laboratory-confirmed cases of the Middle East respiratory syndrome coronavirus (MERS-CoV) have been reported in the Arabian Peninsula, Europe, North Africa, Southeast Asia, the Middle East, and the United States. The observed epidemiology is different to SARS, which showed a classic epidemic curve and was over...
Article
Full-text available
Background The Middle East respiratory syndrome coronavirus (MERS-CoV) represents a current threat to the Arabian Peninsula, and potential pandemic disease. As of June 3, 2014, MERS CoV has reportedly infected 688 people and killed 282. We briefly summarize the state of the outbreak, and highlight unanswered questions and various explanations for t...
Article
The spread of infectious disease is an inherently stochastic process. As such, real time control and prediction methods present a significant challenge. For diseases which spread through direct human interaction, (e.g., transferred from infected to susceptible individuals) the contagion process can be modeled on a social-contact network where indiv...
Article
A high-occupancy/toll (HOT) lane is an increasingly popular form of traffic management strategy which reserves a set of freeway lanes for HOVs and transit users, while allowing low-occupancy vehicles (LOVs) to enter for a fee. In turn, HOT lanes maintain a minimal level of service by regulating the volume of entering LOVs. The focus of this paper i...
Article
Full-text available
The number of travel-acquired dengue infections has seen a consistent global rise over the past decade. An increased volume of international passenger air traffic originating from regions with endemic dengue has contributed to a rise in the number of dengue cases in both areas of endemicity and elsewhere. This paper reports results from a network-b...
Data
Full-text available
Top 100 Travelled Airports Ranked by Passenger Volume. (PDF)
Data
Top 100 Stopover Risk Airports Ranked by Relative Risk. (PDF)
Data
Full-text available
Top 100 Destination Risk Airports Ranked by Relative Risk. (PDF)
Article
The introduction of plug-in electric vehicles (PEVs) represents an unprecedented interaction between the road network and electricity grid. By replacing the traditional fuel source, petrol, with electricity, PEVs will increase the demand for electric power in a region and change emission profiles. Overall, the impacts depend on the eventual penetra...
Conference Paper
The introduction of plug-in electric vehicles (PEVs) represents an unprecedented interaction between the road network and electricity grid. In this new integrated system, travel demand, behavior, and traffic congestion will influence the temporal and spatial characteristics of electricity usage and environmental impacts. Furthermore, uncertainty in...
Article
Plug-in electric vehicles (PEVs) are a rapidly evolving technology representing a potentially sustainable alternative to traditional internal combustion engine vehicles (ICEVs). By relying on electric power rather than petrol, these new vehicles will require a new infrastructure system for en-route charging options, be that fast charging stations o...
Article
Transport network pricing is a topic of interest to transport planners and users alike. Pricing schemes are a vital traffic management strategy which can be implemented to reduce congestion, among other network externalities. Previous research has explored pricing schemes to achieve a variety of network objectives, including social and environmenta...
Article
The objective of this paper is to present a network-based optimization method for identifying links in an air traffic network responsible for carrying infected passengers into previously unexposed regions. The required data include individual infection reports (i.e., when the disease was first reported in a region), travel pattern data, and other g...
Article
Full-text available
The number of travel-acquired dengue infections has been on a constant rise in the United States and Europe over the past decade. An increased volume of international passenger air traffic originating from regions with endemic dengue contributes to the increasing number of dengue cases. This paper reports results from a network-based regression mod...
Article
This paper is concerned with roadway pricing amidst the uncertainty which characterizes long-term transportation planning. Uncertainty is considered both on the supply-side (e.g., the effect of incidents on habitual route choice behavior) and on the demand-side (e.g., due to prediction errors in demand forecasting). The framework developed in this...
Article
Toll prices on traffic networks have been traditionally determined using a single expected demand value or deterministic demand supply relationships. Previous work by Gardner, Unnikrishnan, and Waller (2008) show that marginal social cost prices obtained using the expected value of demand can significantly deteriorate system performance especially...
Article
Traditionally, tolls on transportation networks are determined on the basis of a single value of travel demand, deterministic elastic demand relationships, or informal scenario analysis. However, since the demand on the network cannot be forecast perfectly, pricing may prove to be suboptimal when the realized value of demand deviates significantly...

Network