Posters 2015
Posters presented at(1) 8th Making Cities Liveable Conference, held at Pullman Melbourne on the Park from the 6 - 8 July 2015(2) The International Scientific Conference "Our Common Future under Climate Change", held at UNESCO, Paris Francis from 7-10 July 2015
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Ken Doust / Charlotte WangTitle: Sustainability & Accessibility: The Next Step
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Posters presented at the Civil and Environmental Student Poster Forum19 February 2015 |
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Nima AminiTitle: An Exploratory Assessment of the Associations between the Urban Environment and Obesity Abstract: Obesity and other chronic diseases are becoming more prevalent, as such researchers are trying to examine and combat this trend. A number of studies have shown an association between the built environment and walking. Other studies have shown an association between the built environment and health outcomes. However, contradictory associations have been reported. Review papers have assigned the blame to the well known Modifiable Aerial Unit Problem (MAUP). In this study a large set of data on urban environment in Sydney has been collated and processed to obtain a set of objective urban variables. These variables are guided by the principle concepts of how the urban environment may affect travel behaviour. The obesity and other individual data are obtained from the Household, Income and Labour Dynamics in Australia (HILDA) survey. The MAUP has been addressed through an innovative aggregation method, and have been shown to relate to the probability of being obese using a logit model. The self-selection issue has been addressed by removing the entries that selected their place of residence based on proximity to destinations.
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David ArbisTitle: Modelling Strategic Interactions of Driver Manoeuvres Abstract: Game theory is the study of mathematical models of interaction. In this thesis, it is used to model the interaction of drivers on the road. The study contributes to safety design by better understanding behavioural norms of interaction. Through a game-theoretic approach drivers are assumed to make the best action for themselves, taking into account the observed or predicted action of the competing individual. In this way drivers act according to the interdependence between their own actions and the actions of their competitor. Game theory thusly differentiates from traditional safety modelling approaches that consider drivers acting to one-directional influence. The approach is more holistic and results in a more precise analysis. Further, as game-theoretic models investigate fundamental interaction behaviour, the study findings are generalizable beyond the traffic contexts studied. Resources for this project include non-exhaustively the Australian School of Business Experimental Economics Laboratory (Quad1041) and the TRACSLab Driving Simulator (Building H20, LG8).
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Melissa DuellTitle: The impact of uncertainty on strategic network design projects Abstract: This work addresses the traffic network design problem (NDP), where the planner seeks the optimal locations in a network to which add vehicle capacity in order to minimize an objective, while staying within a budget. While traditionally deterministic, this work expands the NDP to include day-to-day uncertainties in travel demand and link capacity. Specifically, this project proposes a network design formulation that uses a strategic behaviour approach, in which total demand and link capacity are treated as random variables and a strategic user equilibrium results in fixed equilibrium link proportions. The bi-level model is formulated, system performance metrics derived, and then a solution method is developed based on a tailored genetic algorithm. Results under varying levels of volatility reflect possible suboptimal project selection when using a deterministic modelling approach. |
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Sisi JianTitle: Hazard Based Modelling of Vehicle Selection in Carsharing Systems. |
Also presented at TRB 2015 (see below) |
Tao WenTitle: A maximum likelihood estimation of trip tables for the strategic user equilibrium (StrUE) Model |
Also presented at TRB 2015 (see below) |
Kasun WijayaratnaTitle: Dynamic User Optimal traffic Assignment with Recourse |
Also presented at TRB 2015 (see below) |
Posters presented at Transportation Research BoardWalter E. Washington Convention Center. Washington DC, USA
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Melissa DuellTitle: The implications of volatility in day-to-day travel flow and road capacity on traffic network design projects' Abstract: This work addresses the traffic network design problem when day-to-day uncertainties in travel demand and link capacity are taken into account. Specifically, this work proposes a network design formulation that uses a strategic behavior approach, where total demand and link capacity are treated as random variables and a strategic user equilibrium results in fixed equilibrium link proportions. The bilevel model is formulated, system performance metrics derived, and then a solution method is developed based on a tailored genetic algorithm. Results under varying levels of volatility reflect possible suboptimal project selection when using a deterministic modeling approach. |
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Milad GhasrikhouzaniTitle: A Novel System of Disaggregate Models for Travel Demand Modelling, Using Decision Tree and Random Forest Concepts Abstract: This research attempts to address the gap between research and practical transport demand models. Evolution of travel demand models started from the early paper and pencil versions of conventional four-step models of the late 50s and proceeded to the activity-based models. During this transition the emphasis shifted from aggregate to disaggregate models, whereby researchers increasingly paid attention to individual decision making regarding daily activities. This alteration engendered a conspicuous disparity between aggregate and disaggregate models regarding their practicality, precision and policy sensitivity level. This disparity is the main attention of this paper. Unlike the four-step models, a highly disaggregate travel demand modelling structure is proposed in this paper in which trip purpose, mode of transport, time of day, commute distance and attributes of trip destination are modelled. Unlike activity-based models, the proposed method is computational efficient and cost effective making it attractive for small or medium size cities. Destination choice problem is decomposed from the framework by using the attributes of the destination rather than its actual location. All the decisions are modelled using Decision Tree (DT), a Modified version of Decision Tree (MDT), and Random Forest (RF). The model estimation practice is done using the Victorian Integrated Survey of Travel and Activity (VISTA) of 2007 as the training set, and its transferability is examined by utilizing the 2009 year of the same dataset. As the results show RF and DT system of models have a high disaggregate accuracy, whereas MDT and RF system of models predict the aggregate trip patterns in the test dataset more similar to the observations. |
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Milad GhasrikhouzaniTitle: A Residential Relocation Timing and Tenure Choice Modelling Structure: Competing Hazard Based or Cause-Specific Formulation? Abstract: Land use is largely affected by people’s decisions on job and residential relocation as well as decisions by home developers and job providers. In regards to residential relocation decision-making, four fundamental components can be identified: 1) reason(s) of relocation, 2) relocation timing, 3) choosing the next living place, and 4) tenure choice. This paper focuses on the time of relocation and the tenure choice, using the hazard-based structure. A hazard-based model coupled with a logit model is compared against a competing hazard-based model. These two formulations represent two approaches that individuals may consider when evaluating their alternatives. A longitudinal data collected in Australia from the Household, Income, and Labour Dynamics Australia Survey (HILDA) is utilized in this study for developing the models. Several socio-demographic, economic and land use variables are employed to model the behaviour of decision-making unit which mainly consists of a household. It was found that the competing hazard model marginally outperforms the cause-specific structure. |
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Hanna GrzybowskaTitle: A Decision Support System For A Real-Time Field Service Engineer Scheduling Problem With Emergencies And Collaborations Abstract: We treat a dynamic routing and scheduling problem by repeatedly re-planning using a heuristic for solving a variety of the Vehicle Routing Problem. The problem we treat occurs in the situation when Field Service Engineers are assigned a sequence of jobs to attend. The jobs are geographically distributed and not all jobs to be undertaken are known in advance of planning. This dynamic occurrence of job requests is stochastic. Jobs are assigned an Emergency Level, which is the highest for the repair jobs involving a person in danger. In addition some jobs require two engineers to attend. We refer to such jobs as collaborative. Our approach re-schedules the pending jobs in an event-driven manner. The event-driven scheduling process ensures that jobs of high importance, with a high emergency level, are completed promptly. The proposed Decision Support System assists in the decision making concerning the management of Field Service Engineers, in the case when real-time information is available. Its architecture includes two main modules: Simulation Engine and Indigo Solver, using a flexible heuristic based on an Adaptive Large Neighborhood Search. We find that our approach of event-driven re-planning is able to plan for real-world scenarios using significantly fewer resources than are employed in practice. |
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Sisi JianTitle: Hazard Based Modelling of Vehicle Selection in Carsharing Systems. Abstract: Carsharing, as an alternative to private vehicle ownership, has spread worldwide in recent years due to its potential of reducing congestion, improving auto utilization rate and limiting the environmental impact of emissions release. To determine the most efficient allocation of resources within a carsharing programme, it is critical to understand what factors affect the users’ behaviour when selecting vehicles which have been little attended to in the literature. This study attempts to investigate the importance of users’ attributes and fleet characteristics on choice set formation behaviour in selecting vehicles using a Spatial Hazard Based Model (SHBM). In the SHBM model, “distance to the carsharing facility (vehicle pod)” is considered as the prospective decision criteria that carsharing users follow when selecting a vehicle among a set of alternatives This variable is analogous to the duration in a conventional hazard-based model Other factors, such as user socio-demographic attributes, vehicle characteristics, land use type of the trip origin, etc., collected from the Australian carsharing company GoGet are utilized for model estimation. A number of forms of parametric SHBMs are tested to determine the best fit to the data. The accelerated failure time model with a Log-logistic distribution was found to provide the best fit. The estimation results of the coefficients of the parameters suggest that users who do not own a private vehicle, frequent users, elderly users and users with a restriction in the ability to drive tend to consider closer vehicle pods. These findings can provide a starting point for carsharing organisations to optimize their pod locations and types of cars available at different pods to maximize usage. |
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Emily MolyanTitle: Reliability- and Median-Based Identification of Toll Locations in Connected Vehicle Context Abstract: In anticipation of pervasive onboard navigation and electronic payment associated with connected vehicle technology, universal dynamic tolling is a promising possibility for future congestion management. In order to take advantage of these advancements, planners must consider which metrics should be used for the selection and performance evaluation of tolls. This work considers two metrics: median travel time and reliability measured with the 80th percentile travel time index. Each metric is tested for the identification of candidate tolling facilities and for the evaluation of the toll's performance. Using data mining techniques on measured volumes and speeds from California freeways, test tolls are simulated based on the two identification metrics We find that both metrics contribute to the assessment of the toll's success, but travel time reliability is a stronger metric for determining the most effective locations for imposing tolls. |
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Tao WenTitle: A maximum likelihood estimation of trip tables for the strategic user equilibrium (StrUE) Model Abstract: This paper proposes a novel framework to estimate trip tables for the strategic user equilibrium traffic assignment model. The proposed framework uses a bi-level estimation model, where the upper-level is a new maximum likelihood estimation method and the lower-level is the strategic user equilibrium assignment model which accounts for some aspects of day-to-day volatility in traffic flow. The maximum likelihood method proposed in this paper illustrates its ability to utilize information from day-to-day observed link flows in order to provide a unique estimation of the total trip demand distribution. This is accomplished by passing the total trip demand distribution to the strategic user equilibrium model to produce a set of link flow distributions which can then be compared to the link level observations. The mathematical proof demonstrates the convexity of the model. In addition, a numerical analysis is conducted on a test network to illustrate the efficiency of the proposed framework. |
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Kasun WijayaratnaTitle: Dynamic User Optimal traffic Assignment with Recourse Abstract: Limitations of static network equilibrium models have led to numerous research efforts in predicting the temporal and spatial traffic conditions throughout road networks. Static models do not account for the dynamic nature of traffic. Accordingly, new approaches to depict these scenarios have been formulated, such as Dynamic User Optimal (DUO). This study extends DUO to DUO with recourse (DUOR) where a user can also alter their journey en-route dependent on the traffic conditions and the available information through ITS technology. |
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