Water quality modelling of the Barwon Water Supply System

An existing computer model (QUAL2E) was adapted to simulate the flow and water quality of the Barwon Water Supply System, the major water supply system for Geelong. Various water quality parameters were modelled and options reviewed for improving the water quality in this System.

An agent-based approach to value theory and wealth distribution in economics

Any attempt to model an economy requires foundational assumptions about the relations between prices, values and the distribution of wealth. These assumptions exert a profound influence over the results of any model. Unfortunately, there are few areas in economics as vexed as the theory of value. I argue in this paper that the fundamental problem with past theories of value is that it is simply not possible to model the determination of value, the formation of prices and the distribution of income in a real economy with analytic mathematical models. All such attempts leave out crucial processes or make unrealistic assumptions which significantly affect the results. There have been two primary approaches to the theory of value. The first, associated with classical economists such as Ricardo and Marx were substance theories of value, which view value as a substance inherent in an object and which is conserved in exchange. For Marxists, the value of a commodity derives solely from the value of the labour power used to produce it - and therefore any profit is due to the exploitation of the workers. The labour theory of value has been discredited because of its assumption that labour was the only ‘factor’ that contributed to the creation of value, and because of its fundamentally circular argument. Neoclassical theorists argued that price was identical with value and was determined purely by the interaction of supply and demand. Value then, was completely subjective. Returns to labour (wages) and capital (profits) were determined solely by their marginal contribution to production, so that each factor received its just reward by definition. Problems with the neoclassical approach include assumptions concerning representative agents, perfect competition, perfect and costless information and contract enforcement, complete markets for credit and risk, aggregate production functions and infinite, smooth substitution between factors, distribution according to marginal products, firms always on the production possibility frontier and firms’ pricing decisions, ignoring money and credit, and perfectly rational agents with infinite computational capacity. Two critical areas include firstly, the underappreciated Sonnenschein-Mantel- Debreu results which showed that the foundational assumptions of the Walrasian general-equilibrium model imply arbitrary excess demand functions and therefore arbitrary equilibrium price sets. Secondly, in real economies, there is no equilibrium, only continuous change. Equilibrium is never reached because of constant changes in preferences and tastes; technological and organisational innovations; discoveries of new resources and new markets; inaccurate and evolving expectations of businesses, consumers, governments and speculators; changing demand for credit; the entry and exit of firms; the birth, learning, and death of citizens; changes in laws and government policies; imperfect information; generalized increasing returns to scale; random acts of impulse; weather and climate events; changes in disease patterns, and so on. The problem is not the use of mathematical modelling, but the kind of mathematical modelling used. Agent-based models (ABMs), objectoriented programming and greatly increased computer power however, are opening up a new frontier. Here a dynamic bargaining ABM is outlined as a basis for an alternative theory of value. A large but finite number of heterogeneous commodities and agents with differing degrees of market power are set in a spatial network. Returns to buyers and sellers are decided at each step in the value chain, and in each factor market, through the process of bargaining. Market power and its potential abuse against the poor and vulnerable are fundamental to how the bargaining dynamics play out. Ethics therefore lie at the very heart of economic analysis, the determination of prices and the distribution of wealth. The neoclassicals are right then that price is the enumeration of value at a particular time and place, but wrong to downplay the critical roles of bargaining, power and ethics in determining those same prices.

Simulating urban growth in a developing nation's region using a cellular automata-based model

Urbanization is one of the most evident global changes. Research in the field of urban growth modelling has generated models that explore for drivers and components of the urban growth dynamics. Cellular automata (CA) modeling is one of the recent advances, and a number of CA-based models of urban growth have produced satisfactory simulations of spatial urban expansion over time. Most application and test of CA-based models of urban growth which provide likely and reliable simulations has been developed in urban regions of developed nations; urban regions in the United States, in particular. This is because most of the models were developed in universities and research centers of developed nations, and these regions have the required data, which is extensive. Most of the population growth in the world, however, occurs in the developing world. While some European countries show signs of stabilization of their population, in less developed countries, such as India, population still grows exponentially. And this growth is normally uncoordinated, which results in serious environmental and social problems in urban areas. Therefore, the use of existing dynamic–spatial models of urban growth in regions of developing nations could be a means to assist planners and decision makers of these regions to understand and simulate the process of urban growth and test the results of different development strategies. The pattern of growth of urban regions of developing nations, however, seems to be different of the pattern of developed countries. The former use to be more dense and centralized, normally expanding outwards from consolidated urban areas; while the second is normally more fragmented and sparse. The present paper aims to investigate to how extent existing CA-based urban growth models tested in developed nations can also be applied to a developing country urban area. The urban growth model was applied to Porto Alegre City, Brazil. An expected contiguous expansion from existing urban areas has been obtained as following the historical trends of growth of the region. Moreover, the model was sensitive and able to portray different pattern of growth in the study area by changing the value of its parameters.

Microeconomic models of intra-household activity time allocation

The primary purpose of this research is to analyze theoretically the group decisionmaking process leading to the allocation of activity time and the consumption of goods, with particular emphasis in the households. Each household is characterized as a group of individuals making joint decisions about their activity participations, alternative activity time allocations and consumption of various goods, such as independent and joint activity time allocations as well as private and shared consumption patterns. We firstly explore why individual-based models are not realistic in multi-person households, and secondly, we summarize various intra-household activity time allocation models based on different decision-making processes. All models are presented under microeconomic principle of utility maximization to represent the economic behavior of the households.

Function-based single and dual point haptic interaction in Cyberworlds

Polygon and point based models dominate virtual reality. These models also affect haptic rendering algorithms, which are often based on collision with polygons. With application to dual point haptic devices for operations like grasping, complex polygon and point based models will make the collision detection procedure slow. This results in the system not able to achieve interactivity for force rendering. To solve this issue, we use mathematical functions to define and implement geometry (curves, surfaces and solid objects), visual appearance (3D colours and geometric textures) and various tangible physical properties (elasticity, friction, viscosity, and force fields). The function definitions are given as analytical formulas (explicit, implicit and parametric), function scripts and procedures. We proposed an algorithm for haptic rendering of virtual scenes including mutually penetrating objects with different sizes and arbitrary location of the observer without a prior knowledge of the scene to be rendered. The algorithm is based on casting multiple haptic rendering rays from the Haptic Interaction Point (HIP), and it builds a stack to keep track on all colliding objects with the HIP. The algorithm uses collision detection based on implicit function representation of the object surfaces. The proposed approach allows us to be flexible when choosing the actual rendering platform, while it can also be easily adopted for dual point haptic collision detection as well as force and torque rendering. The function-defined objects and parts constituting them can be used together with other common definitions of virtual objects such as polygon meshes, point sets, voxel volumes, etc. We implemented an extension of X3D and VRML as well as several standalone application examples to validate the proposed methodology. Experiments show that our concern about fast, accurate rendering as well as compact representation could be fulfilled in various application scenarios and on both single and dual point haptic devices.

A sequence based dynamic SOM model for text clustering

Text clustering can be considered as a four step process consisting of feature extraction, text representation, document clustering and cluster interpretation. Most text clustering models consider text as an unordered collection of words. However the semantics of text would be better captured if word sequences are taken into account.

In this paper we propose a sequence based text clustering model where four novel sequence based components are introduced in each of the four steps in the text clustering process.

Experiments conducted on the Reuters dataset and Sydney Morning Herald (SMH) news archives demonstrate the advantage of the proposed sequence based model, in terms of capturing context with semantics, accuracy and speed, compared to clustering of documents based on single words and n-gram based models.

Interplay of ethical trust and social moral norms : environment modelling and computational mechanisms in agent-based social simulation

In many agent-based models theoretical and computational mechanisms are needed for model abstraction and design. However, it can be challenging to arrive at the appropriate mechanisms and models. This research on the interplay of ethical trust and social moral norms addresses that challenge via an analytical framework on the spread of moral norms, the modelling of social environment and the selection of spread mechanisms as applied to agent-based social simulation. We describe the mechanism alignment mapping, two forms of interaction modelling between the social environment and agents, and the results obtained from the simulation of our computational model. These results provide an insight into how the agent-based paradigm can be applied as a technique of investigation for normative moral processes in computational social sciences.

Economic models of preventive dentistry for Australian children and adolescents

Purpose:
To identify economic evaluation models and parameters that could be replicated or adapted to construct a generic model to assess cost-effectiveness of and prioritise a wide range of community-based oral disease prevention programmes in an Australian context.
Methods:
The literature search was conducted using MEDLINE, ERIC, PsycINFO, CINHAL (EBSCOhost), EMBASE (Ovid), CRD, DARE, NHSEED, HTA, all databases in the Cochrane library, Scopus and ScienceDirect databases from their inception to November 2012.
Results:
Thirty-three articles met the criteria for inclusion in this review (7 were Australian studies, 26 articles were international). Existing models focused primarily on dental caries. Periodontal disease, another common oral health problem, was lacking. Among caries prevention studies, there was an absence of clear evidence showing continuous benefits from primary through to permanent dentition and the long-term effects of oral health promotion.
Conclusion:
No generic model was identified from previous studies that could be immediately adopted or adapted for our purposes of simulating and prioritising a diverse range of oral health interventions for Australian children and adolescents. Nevertheless, data sources specified in the existing Australian-based models will be useful for developing a generic model for such purposes.

Dynamic performance of duolayers at the air/water interface. 1. Experimental analysis

Understanding, and improving, the behavior of thin surface films under exposure to externally applied forces is important for applications such as mimicking biological membranes, water evaporation mitigation, and recovery of oil spills. This paper demonstrates that the incorporation of a water-soluble polymer into the surface film composition, i.e., formation of a three-duolayer system, shows improved performance under an applied dynamic stress, with an evaporation saving of 84% observed after 16 h, compared to 74% for the insoluble three-monolayer alone. Canal viscometry and spreading rate experiments, performed using the same conditions, demonstrated an increased surface viscosity and faster spreading rate for the three-duolayer system, likely contributing to the observed improvement in dynamic performance. Brewster angle microscopy and dye-tagged polymers were used to visualize the system and demonstrated that the duolayer and monolayer system both form a homogeneous film of uniform, single-molecule thickness, with the excess material compacting into small floating reservoirs on the surface. It was also observed that both components have to be applied to the water surface together in order to achieve improved performance under dynamic conditions. These findings have important implications for the use of surface films in various applications where resistance to external disturbance is required.

Duolayers at the air/water interface: improved lifetime through ionic interactions

Ionic interactions to stabilize Langmuir films at the air/water interface have been used to develop improved duolayer films. Two-component mixtures of octadecanoic (stearic) acid and poly(diallyldimethylammonium chloride) (polyDADMAC) with different ratios were prepared and applied to the water surface. Surface pressure isotherm cycles demonstrated a significant improvement in film stability with the inclusion of the polymer. Viscoelastic properties were measured using canal viscometry and oscillating barriers, with both methods showing that the optimum ratio for improved properties was four octadecanoic acid molecules to one DADMAC unit (1:0.25). At this ratio it is expected multiple strong ionic interactions are formed along each polymer chain. Brewster angle microscopy showed decreased domain size with increased ratios of polyDADMAC, indicating that the polymer is interspersed across the surface. This new method to stabilize and increase the viscoelastic properties of charged monolayer films, using a premixed composition, will have application in areas such as water evaporation mitigation, optical devices, and foaming.

The effect of repeated pulses of light at the same time on period responses of the rat circadian pacemaker.

A consequence of simple velocity-based models is that, in response to light pulses, the circadian period should adjust inversely to phase. In addition, because of the interaction of circadian period and phase response, earlier circadian period changes should modify later circadian period changes. The literature contains few mentions of response curves of circadian period responses following light pulses. Rats were exposed to four pulses of light (60 minutes, 1000 lux) at the same circadian time, a minimum of 26 days apart; we assessed period responses and possible bias in the period-response curve. Modulation of circadian period following light-induced phase responses was examined by assessing the period of running wheel activity onset. Phase and circadian period were not consistently found to share an inverse relationship. Moreover, biases in initial period tended to be increased by the experimental protocol regardless of circadian time of pulse. Rats with a short initial (highvelocity) period had a lengthened period, while rats with a long initial period (low velocity) tended to have a reduce period. However, rats with a long initial period were phase delay biased, not phase advance biased. These results do not support a simple velocity model of the pacemaker.

A holistic model of corporate governance - a new research framework

Purpose – The purpose of this paper is to propose a new model of corporate governance that is holistic – incorporating internal and macro perspectives across legal, regulatory, sociological, ethical, human resource management, behavioural and corporate strategic frameworks. Researchers have signalled the need for “new theoretical perspectives and new models of governance” due to a dearth of research that is context-driven, empirical, and encapsulating the full spectrum of reasons and actions contributing to corporate crises.

Design/methodology/approach – The approach consists of theory building by reviewing the literature and examining the gaps and limitations.

Findings – The proposed model is a distinctive contribution to theory and practice in three ways. First, it integrates the firm-specific, micro factors with the country-specific, macro factors to illustrate the holistic nature of corporate governance. Second, shareholders and stakeholders are shown to be only one component of the model. Third, it veers away from singular approaches, to dealing with corporate governance using a multi-disciplinary perspective. The paper argues that such a holistic and integrated view is a necessity for understanding governance systems.

Research limitations/implications – The challenge is to operationalize the model and test it empirically.

Practical implications – The model is instructive and of use for practitioners in attempting to understand, explain and develop governance models that are appropriate to their national and industry settings.

Originality/value – This paper argues that narrow-based models are limited in their approach and in a sound and integrative review of the up-to-date literature contributes to theory-building on corporate governance.

Skill shortages in health : innovative solutions using vocational education and training

Introduction: This article reports findings of a project funded by the Australian National Council for Vocational Education Research. The project explores solutions to current and projected skills shortages within the health and community services sector, from a vocational education and training perspective. Its purpose is to locate, analyse and disseminate information about innovative models of health training and service delivery that have been developed in response to skill shortages.

Methods: The article begins with a brief overview of Australian statistics and literature on the structure of the national health workforce and perceived skill shortages. The impact of location (state and rurality), demographics of the workforce, and other relevant factors, on health skill shortages is examined. Drawing on a synthesis of the Australian and international literature on innovative and effective models for addressing health skill shortages and nominations by key stakeholders within the health sector, over 70 models were identified. The models represent a mixture of innovative service delivery models and training solutions from Australia, as well as international examples that could be transposed to the Australian context. They include the skill ecosystem approach facilitated by the Australian National Training Authority Skill Ecosystem Project. Models were selected to represent diversity in terms of the nature of skill shortage addressed, barriers overcome in development of the model, healthcare specialisations, and different customer groups.

Results: Key barriers to the development of innovative solutions to skills shortages identified were: policy that is not sufficiently flexible to accommodate changing workplace needs; unwillingness to risk take in order to develop new models; delays in gaining endorsement/accreditation; current vocational education and training (VET) monitoring and reporting systems; issues related to working in partnership, including different cultures, ways of operating, priorities and timelines; workplace culture that is resistant to change; and organisational boundaries. For training-only models, additional barriers were: technology; low educational levels of trainees; lack of health professionals to provide training and/or supervision; and cost of training. Key enhancers for the development of models were identified as: commitment by all partners and co-location of partners; or effective communication channels. Key enhancers for model effectiveness were: first considering work tasks, competencies and job (re)design; high profile of the model within the community; community-based models; cultural fit; and evidence of direct link between skills development and employment, for example VET trained aged care workers upskilling for other health jobs. For training only models, additional enhancers were flexibility of partners in accommodating needs of trainees; low training costs; experienced clinical supervisors; and the provision of professional development to trainers.

Conclusions: There needs to be a balance between short-term solutions to current skill shortages (training only), and medium to longer term solutions (job redesign, holistic approaches) that also address projected skills shortages. Models that focus on addressing skills shortages in aged care can provide a broad pathway to careers in health. Characteristics of models likely to be effective in addressing skill shortages are: responsibility for addressing skills shortage is shared between the health sector, education and training organisations and government, with employers taking a proactive role; the training component is complemented by a focus on retention of workers; models are either targeted at existing employees or identify a target group(s) who may not otherwise have considered a career in health.

Characteristics of the deformed and recrystallised grains obtained after hot plane strain compression of a model Fe-30wt%Ni alloy

The development of physically-based models of microstructural evolution during hot deformation of metallic materials requires knowledge of the grain/subgrain structure and crystallographic texture characteristics over a range of processing conditions. A Fe-30wt%Ni based alloy, retaining a stable austenitic structure at room temperature, was used for modelling the development of austenite microstructure during hot deformation of conventional carbon-manganese steels. A series of plane strain compression tests was carried out at a temperature of 950 °C and strain rates of 10 s-1 and 0.1 s-1 to several strain levels. Evolution of the grain/subgrain structure and crystallographic texture was characterised in detail using quantitative light microscopy and highresolution electron backscatter diffraction. Crystallographic texture characteristics were determined separately for the observed deformed and recrystallised grains. The subgrain geometry and dimensions together with the misorientation vectors across sub-boundaries were quantified in detail across large sample areas and the orientation dependence of these characteristics was determined. Formation mechanisms of the recrystallised grains were established in relation to the deformation microstructure.

EBSD and TEM investigation of the hot deformation substructure characteristics of a type 316L austenitic stainless steel

The evolution of crystallographic texture and deformation substructure was studied in a type 316L austenitic stainless steel, deformed in rolling at 900 °C to true strain levels of about 0.3 and 0.7. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used in the investigation and a comparison of the substructural characteristics obtained by these techniques was made. At the lower strain level, the deformation substructure observed by EBSD appeared to be rather poorly developed. There was considerable evidence of a rotation of the pre-existing twin boundaries from their original orientation relationship, as well as the formation of highly distorted grain boundary regions. In TEM, at this strain level, the substructure was more clearly revealed, although it appeared rather inhomogeneously developed from grain to grain. The subgrains were frequently elongated and their boundaries often approximated to traces of {111} slip planes. The corresponding misorientations were small and largely displayed a non-cumulative character. At the larger strain, the substructure within most grains became well developed and the corresponding misorientations increased. This resulted in better detection of sub-boundaries by EBSD, although the percentage of indexing slightly decreased. TEM revealed splitting of some sub-boundaries to form fine microbands, as well as the localized formation of microshear bands. The substructural characteristics observed by EBSD, in particular at the larger strain, generally appeared to compare well with those obtained using TEM. With increased strain level, the mean subgrain size became finer, the corresponding mean misorientation angle increased and both these characteristics became less dependent on a particular grain orientation. The statistically representative data obtained will assist in the development of physically based models of microstructural evolution during thermomechanical processing of austenitic stainless steels.