Academic literature on the topic 'Commuting Western Australia Perth Mathematical models'

For shale gas reservoirs, permeability is one of the most important and difficult parameters to determine. Typical shale matrix permeabilities are in the range of 10 microdarcy–100 nanodarcy, and are heavily dependent on the presence of natural fractures for gas transmissibility. Permeability is a parameter used to measure the ability of a rock to convey fluid. It is directly related to porosity and depends on the pore geometry features, such as tortuosity, pore shape and pore connectivity. Consequently, rocks with similar porosity can exhibit different permeability. Generally, permeability is measured in laboratories using core plugs. In some cases, however, it is difficult to obtain suitable core plugs. In these instances, other approaches can be used to predict permeability, which are chiefly based on mathematical and theoretical models. The approach followed in this peer-reviewed paper is to correlate permeability with capillary pressure data from mercury injection measurements. The theoretical and empirical equations, introduced in the literature for various conventional and unconventional reservoir rocks, have been used to predict permeability. Estimated gas shale permeabilities are then compared with results from transient and steady state methods on small pieces of rocks embedded in a resin disk. The study also attempts to establish a suitable equation that is applicable to gas shale formations and to investigating the relationship between permeability and porosity.

The ability of public health planners continues to be hampered by uncertainties encountered with transmissible diseases. Key epidemiological factors such as, how many Western Australian injecting drug users are hepatitis C seropositive or will become infected, duration of intravenous drug use, the intensity of infection, the fraction of those infected that will develop end-stage disease and after how long a period, all combine to limit the ability of a mathematical model to predict future trends. These models can, however, provide information about certain epidemiological parameters and identify data required to predict future trends. They can be applied to make predictions about the course of infection in the individual and provide a guide to the interpretation of the observed data. This research aims to develop a model of the transmission and spread of hepatitis C, adapting existing models used to predict the spread of HIV and AIDS in one and two sex communities. This model will be used to demonstrate the dynamics and incidence of hepatitis C infection among injecting drug users in Perth, Western Australia. Predictions derived from the model will then be used to undertake an analysis of the cost of treating those with hepatitis C and cirrhosis related complications, resulting in a prediction of the financial impact of hepatitis C on the Western Australian community.

[Formulae and special characters can only be approximated here. Please see the pdf version of the abstract for an accurate reproduction.] This thesis reviews, extends and applies to urban traffic analysis the entropy concept of Shannon and Luce's mathematical psychology in a fairly complex and mathematically demanding model of human decision making, if it is solved as a deeply nested structure of logit calculus. Recognising consumers' different preferences and the universal propensity to seek the best choice when going to some desired goal (k), a transparent mathematical program (MP) is developed: the equivalent of a nested multinomial logit model without its inherent computational difficulty. The MP model makes a statistical assessment of individual decisions based on a randomised (measurable) utility within a given choice structure: some path through a diagram (Rk, Dk), designed a priori, of a finite number of sequential choices. The Equivalence Theorem (ET) formalises the process and states a non-linear MP with linear constraints that maximises collective satisfaction: utility plus weighted entropy, where the weight (1/θn) is a behavioural parameter to be calibrated in each case, eg for the Perth CBD. An optimisation subject to feasible routes through the (Rk, Dk) network thus captures the rational behaviour of consumers on their individually different best-choice decision paths towards their respective goals (k). This theory has been applied to urban traffic assignment before: a Stochastic User Equi-librium (SUE). What sets this thesis apart is its focus on MP models that can be solved with standard Operations Research software (eg MINOS), models for which the ET is a conditio sine qua non. A brief list of SUE examples in the literature includes Fisk's logit SUE model in (impractically many) route flows. Dial's STOCH algorithm obviates path enumeration, yet is a logit multi-path assignment procedure, not an MP model; it is nei-ther destination oriented nor an optimisation towards a SUE. A revision of Dial's method is provided, named STOCH[k], that computes primal variables (node and link flows) and Lagrangian duals (the satisfaction difference n→k). Sheffi & Powell presented an unconstrained optimisation problem, but favoured a probit SUE, defying closed formulae and standard OR software. Their model corresponds to the (constrained) dual model here, yet the specifics of our primary MP model and its dual are possible only if one restricts himself to logit SUE models, including the ET, which is logit-specific. A real world application needs decomposition, and the Perth CBD example is iteratively solved by Partial Linearisation, switching from (measured) disutility minimisation to Sheffi & Powell's Method of Successive Averages near the optimum. The methodology is demonstrated on the Perth Central Business District (CBD). To that end, parameter Θ is calibrated on Main Roads' traffic count data over the years 1997/98 and 1998/99. The method is a revision of Liu & Fricker's simultaneous estimation of not only Θ but an appropriate trip matrix also. Our method handles the more difficult variable costs (congestion), incomplete data (missing observations) and observation errors (wrong data). Finally, again based on Main Roads' data (a sub-area trip matrix), a Perth CBD traffic assignment is computed, (a) as a logit SUE and - for comparison - (b) as a DUE (using the PARTAN method of Florian, Guélat and Spiess). The results are only superficially similar. In conclusion, the methodology has the potential to replace current DUE models and to deepen transport policy analysis, taking into account individual behaviour and a money-metric utility that quantifies 'social benefits', for instance in a cost-benefit-analysis.

[Truncated abstract] Air pollution is increasingly perceived to be a serious intangible threat to humanity, with air quality continuing to deteriorate in most urban areas. The main sources of inner city pollution are motor vehicles, which generate emissions from the tail pipe as well as by evaporation. These contain toxic gaseous components which have adverse health effects. The major components are carbon monoxide (CO), nitrogen dioxide (NO2), nitric oxide (NO), sulphur dioxide (SO2), particulates (PM10), and volatile organic compounds (VOC). CO and oxides of nitrogen (NOx) are major emissions from cars. This study focuses on pollutant concentration in Perth city and has sought to develop measures to improve air quality. To estimate concentrations, the study develops air pollution models for CO and NOx; on the basis of the model estimates, effective policy is devised to improve the air quality by managing travel to the city. Two peaks, due to traffic, are observed in hourly CO and NOx concentrations. Unlike traffic, however, the morning peak does not reach the level of the afternoon peak. The reasons for this divergence are assessed and quantified. Separate causal models of hourly concentrations of CO and NOx explain their fluctuations accurately. They take account of the complex effects of the urban street canyon and winds in the city. The angle of incidence of the wind has significant impact on pollution level; a wind flow from the south-west increases pollution and wind from the north-east decreases it. The models have been shown to be equivalent to engineering and scientific models in estimating emission rate in the context of street canyons. However the study models are much more precise in the Perth context. ... The models are used to calculate the marginal effects for all attributes and elasticity for fuel price. In almost all attributes the non-work group is more responsive than the work group. Finally, the SP model results are integrated into an econometric model for the purpose of prediction. The travel behaviour prediction is used to estimate the policy impact on air quality. The benefit from the air quality improvement is reported in terms of life saved. The estimated relationships between probability of death and air pollution determines the number of lives that could be saved under various policy scenarios. A ratio of benefits to the financial and perceived sacrifices by drivers is calculated to compare the effectiveness of the suggested policies. A car size charge policy was found to be the most cost effective measure to ameliorate the environmental impact of cars in Perth, with a morning peak entry time charge being almost as cost effective. The study demonstrates the need for appropriate modelling of air pollution and travel behaviour. It brings together analytical methods at three levels of causality, vehicle to air pollution, charge to travel response, and air pollution to health.

[Truncated abstract] The overall aim of the research reported in this thesis was to explore the viability and utility of the construct of psychopathy and aggression in children and adolescents. Specifically, by taking a developmentally informed approach it sought to develop new instrumentation which measured psychopathic-like-traits, and verbal proactive and reactive aggression in non-referred mainstream school children and adolescents. To achieve this, four separate yet interrelated studies were conducted. Study One comprised three phases relating to the development and validation of two new instruments. In Phase One the instruments currently used to measure psychopathy were reviewed and items relevant to young persons were selected for inclusion in a draft version of the new psychopathy screening instrument. Phase Two, which sought to further explore the construct of psychopathy in children and adolescents, comprised a series of interviews with school principals, deputy principals, psychologists, and education officers at the main juvenile detention centre in Perth, Western Australia. These interviews provided information relating to the behaviour and characteristics of children and adolescents who present with psychopathic-like-traits. As a consequence of the feedback from the Phase Two data, Phase Three reviewed the instrumentation currently used to measure aggression in children and adolescents. From this items were selected for possible inclusion in an aggression questionnaire. The data gathered over these three phases resulted in 117 psychopathy related items being generated for the new instrument, which were subsequently reduced to 56 when duplicated items were identified and the extant knowledge of the construct applied. The 56 items were retained in a draft version of the newly developed instrument, which was named the Child and Adolescent Psychopathy Screening Instrument (CAPSI). The Study One data revealed the instrumentation used to date provided few measures of physical and verbal aggression - a characteristic of psychopathic-like behaviour. Thus, a review of instrumentation together with the information from the interviews resulted in 63 aggression items being generated. ... Study Four utilised information from the CAPSI and the CASA in conjunction with in-depth interviews to generate case studies to further elucidate the characteristics of children and adolescents with psychopathic-like-traits and extreme aggression. Case studies were undertaken with seven male students ranging in age from 8 to 15 years who had been suspended from mainstream schools. All boys scored very highly on the new instruments. All presented with extreme aggression, with some exhibiting proactive or premeditated aggression combined with a superficially engaging personality, insincere charm, lack of remorse, and lack of empathy. The findings from all four research studies are discussed in the light of the literature reviewed and the aims of the research. Implications are then drawn for researchers and clinicians, and directions for further research are suggested.