Upgrading arc median shortest path problem for an urban transportation network

In this paper, we propose an algorithm for an upgrading arc median shortest path problem for a transportation network. The problem is to identify a set of nondominated paths that minimizes both upgrading cost and overall travel time of the entire network. These two objectives are realistic for transportation network problems, but of a conflicting and noncompensatory nature. In addition, unlike upgrading cost which is the sum of the arc costs on the path, overall travel time of the entire network cannot be expressed as a sum of arc travel times on the path. The proposed solution approach to the problem is based on heuristic labeling and exhaustive search techniques, in criteria space and solution space, respectively. The first approach labels each node in terms of upgrading cost, and deletes cyclic and infeasible paths in criteria space. The latter calculates the overall travel time of the entire network for each feasible path, deletes dominated paths on the basis of the objective vector and identifies a set of Pareto optimal paths in the solution space. The computational study, using two small-scale transportation networks, has demonstrated that the algorithm proposed herein is able to efficiently identify a set of nondominated median shortest paths, based on two conflicting and noncompensatory objectives.

Solving the median shortest path problem in the planning and design of urban transportation networks using a vector labeling algorithm

This paper proposes an alternative algorithm to solve the median shortest path problem (MSPP) in the planning and design of urban transportation networks. The proposed vector labeling algorithm is based on the labeling of each node in terms of a multiple and conflicting vector of objectives which deletes cyclic, infeasible and extreme-dominated paths in the criteria space imposing cyclic break (CB), path cost constraint (PCC) and access cost parameter (ACP) respectively. The output of the algorithm is a set of Pareto optimal paths (POP) with an objective vector from predetermined origin to destination nodes. Thus, this paper formulates an algorithm to identify a non-inferior solution set of POP based on a non-dominated set of objective vectors that leaves the ultimate decision to decision-makers. A numerical experiment is conducted using an artificial transportation network in order to validate and compare results. Sensitivity analysis has shown that the proposed algorithm is more efficient and advantageous over existing solutions in terms of computing execution time and memory space used.

An algorithm to median shortest path problem (MSPP) in the design of urban transportation networks

This paper proposes an efficient solution algorithm for realistic multi-objective median shortest path problems in the design of urban transportation networks. The proposed problem formulation and solution algorithm to median shortest path problem is based on three realistic objectives via route cost or investment cost, overall travel time of the entire network and total toll revenue. The proposed solution approach to the problem is based on the heuristic labeling and exhaustive search technique in criteria space and solution space of the algorithm respectively. The first labels each node in terms of route cost and deletes cyclic and infeasible paths in criteria space imposing cyclic break and route cost constraint respectively. The latter deletes dominated paths in terms of objectives vector in solution space in order to identify a set of Pareto optimal paths. The approach, thus, proposes a non-inferior solution set of Pareto optimal paths based on non-dominated objective vector and leaves the ultimate decision to decision-makers for purpose specific final decision during applications. A numerical experiment is conducted to test the proposed algorithm using artificial transportation network. Sensitivity analyses have shown that the proposed algorithm is advantageous and efficient over existing algorithms to find a set of Pareto optimal paths to median shortest paths problems.

Predictors of relapse in problem gambling : a prospective cohort study

To explore the variation of predictors of relapse in treatment and support seeking gamblers. A prospective cohort study with 158 treatment and support seeking problem gamblers in South Australia. Key measures were selected using a consensus process with international experts in problem gambling and related addictions. The outcome measures were Victorian Gambling Screen (VGS) and behaviours related to gambling. Potential predictors were gambling related cognitions and urge, emotional disturbance, social support, sensation seeking traits, and levels of work and social functioning. Mean age of participants was 44 years (SD = 12.92 years) and 85 (54 %) were male. Median time for participants enrolment in the study was 8.38 months (IQR = 2.57 months). Patterns of completed measures for points in time included 116 (73.4 %) with at least a 3 month follow-up. Using generalised mixed-effects regression models we found gambling related urge was significantly associated with relapse in problem gambling as measured by VGS (OR 1.29; 95 % CI 1.12-1.49) and gambling behaviours (OR 1.16; 95 % CI 1.06-1.27). Gambling related cognitions were also significantly associated with VGS (OR 1.06; 95 % CI 1.01-1.12). There is consistent association between urge to gamble and relapse in problem gambling but estimates for other potential predictors may have been attenuated because of methodological limitations. This study also highlighted the challenges presented from a cohort study of treatment and support seeking problem gamblers.

The influence of depression and other co-occurring conditions on treatment outcomes for problem gamblers : a cohort study

Objective: To examine the influence of co-occurring conditions on gambling treatment outcomes.

Design, setting and participants: Prospective cohort study of problem gamblers. Participants were recruited from consecutive referrals to a gambling therapy service in 2008. Inclusion criteria were: (i) assessed as a problem gambler based on a screening interview including DSM-IV criteria for pathological gambling, and (ii) suitable for admission to a treatment program. Cognitive-behavioural therapy was based on graded exposure-to-gambling urge. One-to-one treatment was conducted with 1-hour sessions weekly for up to 12 weeks.

Main outcome measures: Problem gambling screening and co-occurring conditions including depression, anxiety and alcohol use.

Results: Of 127 problem gamblers, 69 were males (54%), mean age was 43.09 years, and 65 (51%) reported a duration of problem gambling greater than 5 years. Median time for participants’ enrolment in the study was 8.9 months. Results from mixed effects logistic regression analysis indicated that individuals with higher depression levels had a greater likelihood (13% increase in odds [95% CI, 1%–25%]) of problem gambling during treatment and at follow-up.

Conclusion: Addressing depression may be associated with improved treatment outcomes in problem gambling; conversely, treatment of problem gambling improves affective instability. We therefore recommend a dual approach that treats both depression and problem gambling.

The problem of obesity : is there a role for antagonists of the renin-angiotensin system?

Obesity is a major health problem worldwide; it is associated with more than 30 medical conditions and is a leading cause of unnecessary deaths. Adipose tissue not only acts as an energy store, but also behaves like an endocrine organ, synthesising and secreting numerous hormones and cytokines. Angiotensin II (ANG II) is the biologically active component of the renin-angiotensin system (RAS). The RAS is present in adipose tissue and evidence suggests that ANG II is intimately linked to obesity. Indeed, ANG II increases fat cell growth and differentiation, increases synthesis, uptake and storage of fatty acids and triglycerides and possibly inhibits lipolysis. Evidence obtained using genetically modified animals has shown that the amount of body fat is directly related to the amount of ANG II, i.e., animals with low levels of ANG II have reduced fat stores while animals with excessive ANG II have increased fat stores. In humans, epidemiological evidence has shown that body fat is correlated with angiotensinogen, a precursor of ANG II, or other components of the RAS. Furthermore, blocking the production and/or actions of ANG II with drugs or natural substances decreases body fat. The decrease in body fat caused by such treatments predominantly occurs in abdominal fat depots and appears to be independent of energy intake and digestibility. Clearly, ANG II has an important role in the accumulation of body fat and the possibility exists that treatment of obesity will be enhanced by the use of natural or synthetic substances that interfere with ANG II.

Quantile distribution approach to the one-sample location problem

Most statistical procedures regarding the mean or median may only give valid results when particular conditions about the shape of the data are met. An alternative test is presented in this thesis that does not require certain data shapes but can perform as well or better than the existing tests.

Web-based counseling for problem gambling: exploring motivations and recommendations

Background:

Problem sexual behaviour in children: a review of the literature

   Although there is an under-acknowledgement of the issue in Australia there is a large body of international scholarship on juveniles who exhibit sexually violent or coercive behaviours toward other juveniles. Research undertaken in the United States and the United Kingdom emphasises options for clinical treatment, the logistics of coordinating multi agency response, and the causes and correlatives for coercive sexual behaviours in adolescents. Much of this literature has tended to focus on adolescents and there is an urgent need for increased studies on young children engaging in problem sexual behaviour.

   The smaller body of work published in Australia also favours adolescents rather than children with much of this work heavily influenced by international clinical studies. There are, however, a handful of reports based on Australian practitioner data that do focus on young children who engage in problem sexual behaviour. This literature surveys and evaluates the very limited number of existing therapeutic programs in Australia, and provides interview data with practitioners working with children exhibiting problem sexual behaviour. In the main, this research reinforces the findings of the internationa scholarship, both in terms of the contributing factors to problem sexual activity in children, but also in terms of the need for multi-faceted and contextually based cognitive behavioural therapeutic programs in response. More importantly, this burgeoning field of study indicates how far we have to go both in understanding the extent of the problem in Australia and in fashioning appropriate programs for prevention and intervention. Dr Joe Tucci is Chief Executive Officer of the Australian Childhood Foundation (ACF), an organisation that has taken a lead in responding to childhood problem sexual behaviour. Tucci et al., (2006) claim an urgent need for investment in a dedicated research and response agenda (Staiger et al., 2005b). To effectively address this issue researchers and practitioners require comprehensive empirical data on problem sexual behaviour in children across all sectors of Australian society, including Indigenous communities.