Agent-based model of passenger flows in airport terminals

Passenger flow studies in airport terminals have shown consistent statistical relationships between airport spatial layout and pedestrian movement, facilitating prediction of movement from terminal designs. However, these studies are done at an aggregate level and do not incorporate how individual passengers make decisions at a microscopic level. Therefore, they do not explain the formation of complex movement flows. In addition, existing models mostly focus on standard airport processing procedures such as immigration and security, but seldom consider discretionary activities of passengers, and thus are not able to truly describe the full range of passenger flows within airport terminals. As the route-choice decision-making of passengers involves many uncertain factors within the airport terminals, the mechanisms to fulfill the capacity of managing the route-choice have proven difficult to acquire and quantify. Could the study of cognitive factors of passengers (i.e. human mental preferences of deciding which on-airport facility to use) be useful to tackle these issues? Assuming the movement in virtual simulated environments can be analogous to movement in real environments, passenger behaviour dynamics can be similar to those generated in virtual experiments. Three levels of dynamics have been devised for motion control: the localised field, tactical level, and strategic level. A localised field refers to basic motion capabilities, such as walking speed, direction and avoidance of obstacles. The other two fields represent cognitive route-choice decision-making. This research views passenger flow problems via a "bottom-up approach", regarding individual passengers as independent intelligent agents who can behave autonomously and are able to interact with others and the ambient environment. In this regard, passenger flow formation becomes an emergent phenomenon of large numbers of passengers interacting with others. In the thesis, first, the passenger flow in airport terminals was investigated. Discretionary activities of passengers were integrated with standard processing procedures in the research. The localised field for passenger motion dynamics was constructed by a devised force-based model. Next, advanced traits of passengers (such as their desire to shop, their comfort with technology and their willingness to ask for assistance) were formulated to facilitate tactical route-choice decision-making. The traits consist of quantified measures of mental preferences of passengers when they travel through airport terminals. Each category of the traits indicates a decision which passengers may take. They were inferred through a Bayesian network model by analysing the probabilities based on currently available data. Route-choice decision-making was finalised by calculating corresponding utility results based on those probabilities observed. Three sorts of simulation outcomes were generated: namely, queuing length before checkpoints, average dwell time of passengers at service facilities, and instantaneous space utilisation. Queuing length reflects the number of passengers who are in a queue. Long queues no doubt cause significant delay in processing procedures. The dwell time of each passenger agent at the service facilities were recorded. The overall dwell time of passenger agents at typical facility areas were analysed so as to demonstrate portions of utilisation in the temporal aspect. For the spatial aspect, the number of passenger agents who were dwelling within specific terminal areas can be used to estimate service rates. All outcomes demonstrated specific results by typical simulated passenger flows. They directly reflect terminal capacity. The simulation results strongly suggest that integrating discretionary activities of passengers makes the passenger flows more intuitive, observing probabilities of mental preferences by inferring advanced traits make up an approach capable of carrying out tactical route-choice decision-making. On the whole, the research studied passenger flows in airport terminals by an agent-based model, which investigated individual characteristics of passengers and their impact on psychological route-choice decisions of passengers. Finally, intuitive passenger flows in airport terminals were able to be realised in simulation.

Experiments with cooperative control of underwater robots

In this paper we describe cooperative control algorithms for robots and sensor nodes in an underwater environment. Cooperative navigation is defined as the ability of a coupled system of autonomous robots to pool their resources to achieve long-distance navigation and a larger controllability space. Other types of useful cooperation in underwater environments include: exchange of information such as data download and retasking; cooperative localization and tracking; and physical connection (docking) for tasks such as deployment of underwater sensor networks, collection of nodes and rescue of damaged robots. We present experimental results obtained with an underwater system that consists of two very different robots and a number of sensor network modules. We present the hardware and software architecture of this underwater system. We then describe various interactions between the robots and sensor nodes and between the two robots, including cooperative navigation. Finally, we describe our experiments with this underwater system and present data.

Interference in text categorisation experiments

This article examines manual textual categorisation by human coders with the hypothesis that the law of total probability may be violated for difficult categories. An empirical evaluation was conducted to compare a one step categorisation task with a two step categorisation task using crowdsourcing. It was found that the law of total probability was violated. Both a quantum and classical probabilistic interpretations for this violation are presented. Further studies are required to resolve whether quantum models are more appropriate for this task.

Effect of the mediator in feedback mode-based SECM interrogation of indium tin-oxide and boron-doped diamond electrodes

Indium tin-oxide (ITO) and polycrystalline boron-doped diamond (BDD) have been examined in detail using the scanning electrochemical microscopy technique in feedback mode. For the interrogation of electrodes made from these materials, the choice of mediator has been varied. Using Ru(CN) 4− 6 (aq), ferrocene methanol (FcMeOH), Fe(CN) 3− 6 (aq) and Ru(NH 3) 3+ 6 (aq), approach curve experiments have been performed, and for purposes of comparison, calculations of the apparent heterogeneous electron transfer rates (k app) have been made using these data. In general, it would appear that values of k app are affected mainly by the position of the mediator reversible potential relative to the relevant semiconductor band edge (associated with majority carriers). For both the ITO (n type) and BDD (p type) electrodes, charge transfer is impeded and values are very low when using FcMeOH and Fe(CN) 3− 6 (aq) as mediators, and the use of Ru(NH 3) 3+ 6(aq) results in the largest value of k app. With ITO, the surface is chemically homogeneous and no variation is observed for any given mediator. Data is also presented where the potential of the ITO electrode is fixed using a ratio of the mediators Fe(CN) 3− 6(aq) and Fe(CN) 4− 6(aq). In stark contrast, the BDD electrode is quite the opposite and a range of k app values are observed for all mediators depending on the position on the surface. Both electrode surfaces are very flat and very smooth, and hence, for BDD, variations in feedback current imply a variation in the electrochemical activity. A comparison of the feedback current where the substrate is biased and unbiased shows a surprising degree of proportionality.

Buckling experiments on hollow flange beams with web stiffeners

A new cold-formed and resistance welded section known as the Hollow Flange Beam (HFB) has been developed recently in Australia. In contrast to the common lateral torsional buckling mode of I-beams, this unique section comprising two stiff triangular flanges and a slender web is susceptible to a lateral distortional buckling mode of failure involving lateral deflection, twist and cross-section change due to web distortion. This lateral distortional buckling behaviour has been shown to cause significant reduction of the available flexural strength of HFBs. An investigation using finite element analyses and large scale experiments was carried out into the use of transverse web plate stiffeners to improve the lateral buckling capacity of HFBs. This paper presents the details of the experimental investigation, the results, and the final stiffener arrangement whereas the details of the finite element analyses are presented in a companion paper at this conference.

Buckling experiments on hollow flange beams with web stiffeners

The hollow flange beam (HFB) is a new cold-formed and resistance-welded section developed in Australia. Due to its unique geometry comprising two stiff triangular flanges and a slender web, the HFB is susceptible to a lateral-distortional buckling mode of failure involving web distortion. Investigation using finite-element analyses showed that the use of transverse web plate stiffeners effectively eliminated lateral-distortional buckling of HFBs and thus any associated reduction in flexural capacity. A detailed experimental investigation was then carried out to validate the results from the finite-element analysis and to improve the stiffener configuration further. This led to the development of a special stiffener that is screw-fastened to the flanges on alternate sides of the web. This paper presents the details of the experimental investigations, the results, and the final stiffener arrangement whereas the details of the finite-element analyses are presented in a companion paper.

Implementation of a better choice healthy food and drink supply strategy for staff and visitors in government owned health facilities in Queensland, Australia

Objective The present paper reports on a quality improvement activity examining implementation of A Better Choice Healthy Food and Drink Supply Strategy for Queensland Health Facilities (A Better Choice). A Better Choice is a policy to increase supply and promotion of healthy foods and drinks and decrease supply and promotion of energy-dense, nutrient-poor choices in all food supply areas including food outlets, staff dining rooms, vending machines, tea trolleys, coffee carts, leased premises, catering, fundraising, promotion and advertising. Design An online survey targeted 278 facility managers to collect self-reported quantitative and qualitative data. Telephone interviews were sought concurrently with the twenty-five A Better Choice district contact officers to gather qualitative information. Setting Public sector-owned and -operated health facilities in Queensland, Australia. Subjects One hundred and thirty-four facility managers and twenty-four district contact officers participated with response rates of 48·2 % and 96·0 %, respectively. Results Of facility managers, 78·4 % reported implementation of more than half of the A Better Choice requirements including 24·6 % who reported full strategy implementation. Reported implementation was highest in food outlets, staff dining rooms, tea trolleys, coffee carts, internal catering and drink vending machines. Reported implementation was more problematic in snack vending machines, external catering, leased premises and fundraising. Conclusions Despite methodological challenges, the study suggests that policy approaches to improve the food and drink supply can be implemented successfully in public-sector health facilities, although results can be limited in some areas. A Better Choice may provide a model for improving food supply in other health and workplace settings.

Facial expression recognition experiments with data from television broadcasts and the world wide web

Facial expression recognition (FER) systems must ultimately work on real data in uncontrolled environments although most research studies have been conducted on lab-based data with posed or evoked facial expressions obtained in pre-set laboratory environments. It is very difficult to obtain data in real-world situations because privacy laws prevent unauthorized capture and use of video from events such as funerals, birthday parties, marriages etc. It is a challenge to acquire such data on a scale large enough for benchmarking algorithms. Although video obtained from TV or movies or postings on the World Wide Web may also contain ‘acted’ emotions and facial expressions, they may be more ‘realistic’ than lab-based data currently used by most researchers. Or is it? One way of testing this is to compare feature distributions and FER performance. This paper describes a database that has been collected from television broadcasts and the World Wide Web containing a range of environmental and facial variations expected in real conditions and uses it to answer this question. A fully automatic system that uses a fusion based approach for FER on such data is introduced for performance evaluation. Performance improvements arising from the fusion of point-based texture and geometry features, and the robustness to image scale variations are experimentally evaluated on this image and video dataset. Differences in FER performance between lab-based and realistic data, between different feature sets, and between different train-test data splits are investigated.

Non-response bias in randomized control experiments in criminology : putting the Queensland Community Engagement Trial (QCET) under a microscope

Objectives The goal of this article is to examine whether or not the results of the Queensland Community Engagement Trial (QCET)-a randomized controlled trial that tested the impact of procedural justice policing on citizen attitudes toward police-were affected by different types of nonresponse bias. Method We use two methods (Cochrane and Elffers methods) to explore nonresponse bias: First, we assess the impact of the low response rate by examining the effects of nonresponse group differences between the experimental and control conditions and pooled variance under different scenarios. Second, we assess the degree to which item response rates are influenced by the control and experimental conditions. Results Our analysis of the QCET data suggests that our substantive findings are not influenced by the low response rate in the trial. The results are robust even under extreme conditions, and statistical significance of the results would only be compromised in cases where the pooled variance was much larger for the nonresponse group and the difference between experimental and control conditions was greatly diminished. We also find that there were no biases in the item response rates across the experimental and control conditions. Conclusion RCTs that involve field survey responses-like QCET-are potentially compromised by low response rates and how item response rates might be influenced by the control or experimental conditions. Our results show that the QCET results were not sensitive to the overall low response rate across the experimental and control conditions and the item response rates were not significantly different across the experimental and control groups. Overall, our analysis suggests that the results of QCET are robust and any biases in the survey responses do not significantly influence the main experimental findings.

A question of agency : applying Sen’s theory of human capability to the concept of secondary school student career ‘choice’

In this paper, we seek to operationalize Amartya Sen's concept of human capability to guide a scholarly investigation of student career choice capability. We begin by outlining factors affecting youth labour markets in Australia; a prosperous country that is affected by a ‘two-speed’ national economy. We then examine recent government initiatives that have been designed to combat youth unemployment and cyclical disadvantage by enhancing the aspirations and career knowledge of secondary school students. We argue that these policy measures are based on four assumptions: first, that career choice capability is a problem of individual agency; second, that the dissemination of career information can empower students to act as ‘consumers’ in an unequal job market; third, that agency is simply a question of will; and finally, that school education and career advice – as a means to freedom in the space of career development – is of equal quality, distribution and value to an increasingly diverse range of upper secondary school students. The paper concludes by outlining a conceptual framework capable of informing an empirical research project that aims to test these assumptions by measuring and comparing differences between groups in the range of freedom to achieve and, therefore, to choose.

Who struggles most in making a career choice and why?Findings from a cross-sectional survey of highschool students

This paper reports findings from an empirical study examining the influence of student background and educational experiences on the development of career choice capability. Secondary school students attending years 9-12 (N = 706) in New South Wales (NSW), Australia, were invited to participate in an online survey that sought to examine factors influencing their career choices. The survey included questions relating to student demographics, parental occupation, attitudes to school and to learning, student aspirations, and students’ knowledge of the further education or skills required to achieve their desired goal. We found no significant differences in the proportions of students who were “uncertain” of their future career aspirations with respect to their socio-educational background. There were, however, significantly more students struggling with career decision making from an English-speaking background in comparison to households where children spoke a language other than English. Those students were proportionally present in government and non-government schools and had some behavioural and attitudinal characteristics in common.

Built to last or meant to end : intertemporal choice in strategic alliance portfolios

A salient but rarely explicitly studied characteristic of interfirm relationships is that they can intentionally be formed for finite periods of time. What determines firms' intertemporal choices between different alliance time horizons? Shadow of the future theorists suggest that when an alliance has an explicitly set short-term time frame, there is an increased risk that partners may behave opportunistically. This does not readily explain the high incidence of time-bound alliances being formed. Reconciling insights from the shadow of the future perspective with nascent research on the flexibility of temporary organizations, and shifting the focus from the level of individual transactions to that of strategic alliance portfolios, we argue that firms may be willing to accept a higher risk of opportunism when there are offsetting gains in strategic flexibility in managing their strategic alliance portfolio. Consequently, we hypothesize that environmental factors that increase the need for strategic flexibility—namely, dynamism and complexity in the environment—are likely to increase the relative share of time-bound alliances in strategic alliance portfolios. Our analysis of longitudinal data on the intertemporal alliance choices of a large sample of small and medium-sized enterprises provides support for this argument. Our findings fill an important gap in theory about time horizons in interfirm relationships and temporary organizations and show the importance of separating planned terminations from duration-based performance measures.

Substrate choice of membrane-type 1 matrix metalloproteinase is dictated by tissue inhibitor of metalloproteinase-2 levels

Although tissue inhibitor of metalloproteinase-2 (TIMP-2) is known to be not only an inhibitor of matrix metalloproteinases (MMP) but also a cofactor for membrane-type 1 MMP (MT1-MMP)-mediated MMP-2 activation, it is still unclear how TIMP-2 regulates MMP-2 activation and cleavage of substrates by MT1-MMP. In the present study we examined the levels of cell-surface MT1-MMP, MMP-2 activation and cleavage of MT1-MMP substrates in 293T cells transfected with the MT1-MMP and TIMP-2 genes. Co-expression of TIMP-2 at an appropriate level increased the level of cell-surface MT1-MMP, both the TIMP-2-bound and free forms, and generated processed MMP-2 with gelatin-degrading activity. In contrast, MT1-MMP substrates testican-1 and syndecan-1 were cleaved by the cells expressing MT1-MMP, which was inhibited by TIMP-2 even at levels that stimulate MMP-2 activation. These results suggest that TIMP-2 environment determines MT1-MMP substrate choice between direct cleavage of its own substrates and MMP-2 activation.