Structured development of an asynchronous forth processor using trace theory

This thesis examines the use of a structured design methodology in the design of asynchronous circuits so that high level constructs can be specified purely in terms of signal exchanges and without the intrusion of lower level concepts. Trace theory is used to specify a multi-processor Forth machine at a high level then part of the design is further elaborated using trace theory operations to (insure that the behaviours of the lower level constructs will combine to give the high level specified behaviour without locking or other hazards. A novel form of threaded language to take advantage of the machine architecture is developed. At suitable points the design is tested by simulation. The stack element which is designed is reduced to an electric circuit which is itself tested by simulation to verify the design.

Exposure to fumes and gases during welding operations

The exposure to fumes and gases is one of the hazards associated with welding operations. Apart from research conducted on the mechanism of fume and gas formation and the relationship between fume formation rates and common welding parameters, little is known about the exposure process during welding. This research project aimed to identify the factors that influence exposure, develop an understanding of their role in the exposure process and through this understanding formulate strategies for the effective control of exposure during welding. To address these aims a literature review and an experimental program was conducted The literature review surveyed epidemiological, toxicological and exposure data. The experimental program involved three approaches, the first, an evaluation of the factors that influence exposure by assessing a metal inert gas/mild steel welding process in a workshop setting. The second approach involved the study of exposure in a controlled environment provided by a wind tunnel and simulated welding process. The final approach was to investigate workplace conditions through an assessment of exposure and control strategies in industry. The exposure to fumes and gases during welding is highly variable and frequently in excess of the health based exposure standards. Exposure is influenced by a number of a factors including the welding process, base material, arc time, electrode, arc current, arc voltage, arc length, electrode polarity, shield gas, wire-to-metal-work distance (metal inert gas), metal transfer mode, intensity of the UV radiation (ozone), the frequency of arc ignitions (ozone), thermal buoyancy generated by the arc process, ventilation (natural and mechanical), the welding environment, the position of the welder, the welders stance, helmet type, and helmet position. Exposure occurs as a result of three processes: the formation of contaminants at or around the arc region; their transport from the arc region, as influenced by the entry and thermal expansion of shield gases, the vigorous production of contaminants, thermal air currents produced by the heat of the arc process, and ventilation; and finally the entry of contaminants into the breathing zone of the welder, as influenced by the position of the welder, the welders stance, helmet type, and the helmet position. The control of exposure during welding can be achieved by several means: through the selection of welding parameters that generate low contaminant formation rates; through the limitation of arc time; and by isolating the breathing zone of the welder from the contaminant plume through the use of ventilation, welder position or the welding helmet as a physical barrier. Effective control is achieved by careful examination of the workplace, the selection of the most appropriate control option, and motivation of the workforce.

Occupational health and safety management systems : system types and effectiveness

The aim of this thesis is to develop a framework to evaluate the relative performance of different types of health and safety management system. This objective is an analytical one, but it stems from a policy issue of public importance. Over the past decade Australia, like other countries, has seen the emergence and growth of interest in developing health and safety management systems. But are they all the same, and if not, do they differ in their effectiveness? The thesis does not seek to give a definitive answer to these questions. Given the novelty of the phenomenon and the lack of research on this subject, the research is exploratory. An hypothesis about the effectiveness of different health and safety management systems is developed rather than tested. The thesis proceeds by first defining health and safety management systems as a combination of the planning and review, the management arrangements, the consultative arrangements and the specific program elements that work together in an integrated way to improve health and safety performance. A research procedure is described involving twenty exploratory case studies. The thesis then - develops - from the literature and the case study research - an analytical framework to evaluate the performance of different health and safety management systems. That framework has two parts. First is a typology of health and safety management systems. This is constructed from two distinctions - between 'safe place' and 'safe person' approaches to health and safety; and between 'innovative' and traditional' management methods and structures. These distinctions yield four types of system. The typology was applied to the case studies which yielded a reasonable fit in most instances. The second part of the framework is a 'process evaluation' technique akin to Quality standards. Derived from the Victorian SafetyMAP audit criteria, the "e;process evaluation tool "e; is preferred to traditional outcome measures such as incident or claim rates. Using this measure, the twenty case study enterprises were classified as above average, average or below average in performance. These results correlated poorly with traditional incident trend and benchmark measures. The two elements of the framework are then combined to explore the relationship between the different types of system and their performance. Evidence from the twenty case studies showed a tendency for innovative/safe place firms to perform better than traditional/safe person firms. This finding can form the basis for a hypothesis that may be subject to statistical testing on a generalisable sample. In addition five 'best practice' cases were selected and subjected to a cross case analysis to search for common characteristics that might explain their performance. This analysis suggests the importance of a number of factors: senior managers who drive health and safety change and mobilise all possible resources in the pursuit of change; health and safety representatives who work with managers in a 'joint regulatory relationship' across system activities; the involvement of employees more generally, but not as a substitute for action by managers and health and safety representatives; a comprehensive approach to elimination of all hazards; and the introduction of innovative programs to continually improve systems and facilitate employee involvement in health and safety.

Ecology of arboreal marsupials in a network of remnant linear habitats

Linear strips of vegetation set within a less-hospitable matrix are common features of landscapes throughout the world. Depending on location, form and function, these linear landscape elements include hedgerows, fencerows, shelterbelts, roadside or streamside strips and wildlife corridors. In many anthropogenically-modified landscapes, linear strips are important components for conservation because they provide a large proportion of the remaining wooded or shrubby habitat for fauna. They may also function to provide connectivity across the landscape. In some districts, the linear strips form an interconnected network of habitat. The spatial configuration of remnant habitat (size, shape and arrangement) may influence habitat suitability, and hence survival, of many species of plant and animal in modified landscapes. Near Euroa in south-eastern Australia, the clearing and fragmentation of temperate woodlands for agriculture has been extensive and, at present, less than 5% tree cover remains, most of which (83%) occurs as linear strips along roads and streams. The remainder of the woodland occurs as relatively small patches and single isolated trees scattered across the landscape. As an assemblage, arboreal marsupials are woodland dependent and vary in their sensitivity to habitat loss and fragmentation. This thesis focusses on determining the conservation status of arboreal marsupials in the linear network and understanding how they utilise the landscape mosaic. Specifically, the topics examined in this thesis are: (1) the composition of the arboreal marsupial assemblage in linear and non-linear woodland remnants; (2) the status and habitat preferences of species of arboreal marsupial within linear remnants; and (3) the ecology of a population of the Squirrel Glider Petaurus norfolcensis in the linear network, focusing on population dynamics, spatial organisation, and use of den trees. The arboreal marsupial fauna in the linear network was diverse, and comprised seven out of eight species known to occur in the district. The species detected within the strips were P. norfolcensis, the Sugar Glider Petaurus breviceps, Common Brushtail Possum Trichosums vulpecula, Common Ringtail Possum Pseudocheirus peregrinus, Brush-tailed Phascogale Phascogale tapoatafa, Koala Phascolarctos cinereus and Yellow-footed Antechinus Antechinus flavipes. The species not detected was the Feathertail Glider Acrabates pygmaeus. Survey sites in linear remnants (strips of woodland along roads and streams) supported a similar richness and density of arboreal mammals to sites in non-linear remnants (large patches or continuous tracts of woodland nearby). Furthermore, the combined abundance of all species of arboreal marsupials was significantly greater in sites in the linear remnants than in the non-linear remnants. This initial phase of the study provided no evidence that linear woodland remnants support a degraded or impoverished arboreal marsupial fauna in comparison with the nonlinear remnants surveyed. Intensive trapping of arboreal marsupials within a 15 km linear network between February 1997 and June 1998 showed that all species of arboreal marsupial (except A. pygmaeus) were present within the linear strips. Further analyses related trap-based abundance estimates to measures of habitat quality and landscape structure. Width of the linear habitat was significantly positively correlated with the combined abundance of all arboreal marsupials, as well as with the abundance of P. norfolcensis and T. vulpecula. The abundance of T. vulpecula was also significantly positively correlated with variation in overstorey species composition, Acacia density and the number of hollow-bearing trees. The abundance of P. norfolcensis was positively correlated with Acacia density and canopy width, and negatively correlated with distance to the nearest intersection with another linear remnant. No significant variables were identified to explain the abundance of P. tapoatafa, and there were insufficient captures of the remaining species to investigate habitat preferences. Petaurus norfolcensis were resident within the linear network and their density (0.95 -1.54 ha-1) was equal to the maximum densities recorded for this species in continuous forest elsewhere in south-eastern Australia. Rates of reproduction were also similar to those in continuous forest, with births occurring between May and December, a mean natality rate of 1.9, and a mean litter size of 1.7. Sex ratios never differed significantly from parity. Overall, the population dynamics of P. norfolcensis were comparable with published results for the species in contiguous forest, clearly suggesting that the linear remnants currently support a self-sustaining, viable population. Fifty-one P. norfolcensis were fitted with radio transmitters and tracked intermittently between December 1997 and November 1998. Home ranges were small (1.3 - 2.8 ha), narrow (20 - 40 m) and elongated (322 - 839 m). Home ranges were mostly confined to the linear remnants, although 80% of gliders also utilised small clumps of adjacent woodland within farm paddocks for foraging or denning. Home range size was significantly larger at intersections between two or more linear remnants than within straight sections of linear remnants. Intersections appeared to be important sites for social interaction because the overlap of home ranges of members of adjacent social groups was significantly greater at intersections than straight sections. Intersections provided the only opportunity for members of three or more social groups to interact, while still maintaining their territories. The 51 gliders were radiotracked to 143 different hollow-bearing trees on 2081 occasions. On average, gliders used 5.3 den trees during the study (range 1-15), and changed den trees every 4.9 days. The number of den trees used by each glider is likely to be conservative because the cumulative number of den trees continued to increase over the full duration of the study. When gliders shifted between den trees, the mean distance between consecutive den sites was 247 m. Den trees were located throughout a glider's home range, thereby reducing the need to return to a central den site and potentially minimising energy expenditure. Dens were usually located in large trees (mean diameter 88.5 cm) and were selected significantly more often than expected based on their occurrence within the landscape. The overall conclusion of this thesis is that the linear network I studied provides high quality habitat for resident populations of arboreal marsupials. Important factors influencing the suitability of the linear remnants appear to be the high level of network connectivity, the location on soils of high nutrient status, the high density of large trees and an acacia understorey. In highly fragmented landscapes, linear habitats as part of the remaining woodland mosaic have the potential to be an integral component in the conservation of woodland-dependent fauna. The habitat value of linear strips of vegetation should not be underestimated.

Performance evaluation and improved risk control philosophies for drinking water systems

World-wide, water is the single most used substance by humans every day. Water is also the major cause of illness and death in many countries including the affluent nations. Through this research, new risk control philosophies from catchment to consumers are highlighted. This thesis is about identifying the hazards, evaluating the risks and implementing controls to protect public health from drinking water.

Achieving growth in the Pacific islands : an introduction

The Small Island Developing States (SIDS)1 in the Pacific, spread out over an area of 30 million square kilometres of ocean, and home to over 9 million people, face a complex and unique set of development challenges. As small, highly open economies they are particularly susceptible to external shocks, including fluctuations in import prices and export earnings in particular. Remoteness from major ports and export markets, low levels of connectivity with the outside world and susceptibility to natural hazards further complicate matters and have resulted in the Pacific islands being amongst the most vulnerable economies in the world. In spite of their increasing integration into global markets, most face further challenges owing to very limited absorptive capacities, limited resources, inadequate technology, lack of infrastructure and poor economic management and institutional capabilities. As a consequence, economic growth and related outcomes in most remain heavily reliant on external resources, typically including at least one of aid, migrant remittances, and foreign direct investment (FDI) (AusAID 2008 and McGillivray et al. 2008). The particular constraints and growth challenges of Pacific SIDS are too often overlooked in the development research literature. Moreover, the policy debate on how to promote and achieve growth in the Pacific islands can benefit from a deeper understanding of the nature and consequences of these often unique, combination of constraints. This Focus is devoted to development challenges facing these islands, specifically relating to the achievement of economic growth, and draws on five papers that were presented or tabled at the World Institute for Development Economics Research (WIDER) ‘Fragility and Development’ research project meeting held in Fiji in December 2006.

The transformation of development strategy in Korea : a 'risk society' perspective

After undergoing rapid socio-economic and political transformation, the Republic of Korea has arrived at the stage of development which Beck refers to as a risk society. Korea has experienced both sides of the risks which accompany modernity: the wealth associated with an advanced economy and also the hazards which are by-products of industrial society. However the Korean case is distinctive, this article argues, due to the state’s role in calibrating and managing risk. Whereas prior to the financial crisis of 1997–98 state elites privileged big business and exposed workers to higher levels of risk, calculations of the costs and benefits of risk have changed since the financial crisis. A notable outcome has been the straining of traditionally close ties between the state and the chaebŏl.

Fire management on private conservation lands : knowledge, perceptions and actions of landholders in eastern Australia

Fire is an important natural disturbance process within the Australian landscape, but the complex and hazardous nature of fire creates a conservation management dilemma. For landholders of private conservation lands, management for conservation of biodiversity and risk reduction is complicated. Private conservation landholders in eastern Australia directed far less effort towards fire management than other conservation management actions, despite clearly acknowledging the risk and associated responsibilities of fire management on their lands. Nonetheless, landholders did undertake actions to reduce fuel hazards and prepare for wildfire events on their land. Despite the established role and benefits of fire to many ecosystems in the region, landholder understanding of the ecological role of fire was generally poor. Few landholders were aware of ecologically appropriate fire regimes for the vegetation types on their property, and few undertook fire management actions to achieve ecological outcomes. Site-specific obstacles, lack of fire management knowledge and experience, and legal and containment concerns contributed to the low level of fire management observed. There is a need for property-specific fire management planning across all private conservation lands, to further integrate ecological fire requirements into biodiversity management, and prioritise actions that aim to improve conservation outcomes while safeguarding life and property.

Age at quitting smoking as a predictor of risk of cardiovascular disease incidence independent of smoking status, time since quitting and pack-years

Background: Risk prediction for CVD events has been shown to vary according to current smoking status, pack-years smoked over a lifetime, time since quitting and age at quitting. The latter two are closely and inversely related. It is not known whether the age at which one quits smoking is an additional important predictor of CVD events. The aim of this study was to determine whether the risk of CVD events varied according to age at quitting after taking into account current smoking status, lifetime pack-years smoked and time since quitting.
Findings. We used the Cox proportional hazards model to evaluate the risk of developing a first CVD event for a cohort of participants in the Framingham Offspring Heart Study who attended the fourth examination between ages 30 and 74 years and were free of CVD. Those who quit before the median age of 37 years had a risk of CVD incidence similar to those who were never smokers. The incorporation of age at quitting in the smoking variable resulted in better prediction than the model which had a simple current smoker/non-smoker measure and the one that incorporated both time since quitting and pack-years. These models demonstrated good discrimination, calibration and global fit. The risk among those quitting more than 5 years prior to the baseline exam and those whose age at quitting was prior to 44 years was similar to the risk among never smokers. However, the risk among those quitting less than 5 years prior to the baseline exam and those who continued to smoke until 44 years of age (or beyond) was two and a half times higher than that of never smokers.
Conclusions: Age at quitting improves the prediction of risk of CVD incidence even after other smoking measures are taken into account. The clinical benefit of adding age at quitting to the model with other smoking measures may be greater than the associated costs. Thus, age at quitting should be considered in addition to smoking status, time since quitting and pack-years when counselling individuals about their cardiovascular risk.

Epidemiologic merit of obese-years, the combination of degree and duration of obesity

This study aims to test the effect of combining the degree and the duration of obesity into a single variable-obese-years-and to examine whether obese-years is a better predictor of the risk of diabetes than simply body mass index (BMI) or duration of obesity. Of the original cohort of the Framingham Heart Study, 5,036 participants were followed up every 2 years for up to 48 years (from 1948). The variable, obese-years, was defined by multiplying for each participant the number of BMI units above 30 kg/m(2) by the number of years lived at that BMI. Associations with diabetes were analyzed by using time-dependent Cox proportional hazards regression models adjusted for potential confounders. The incidence of type-2 diabetes increased as the number of obese-years increased, with adjusted hazard ratios of 1.07 (95% confidence interval: 1.06, 1.09) per additional 10 obese-years. The dose-response relation between diabetes incidence and obese-years varied by sex and smoking status. The Akaike Information Criterion was lowest in the model containing obese-years compared with models containing either the degree or duration of obesity alone. A construct of obese-years is strongly associated with risk of diabetes and could be a better indicator of the health risks associated with increasing body weight than BMI or duration of obesity alone.

The contributions of first nations ethnicity, income, and delays in surgery on mortality post-fracture : a population-based analysis

Summary We examined the independent contributions of First Nations ethnicity and lower income to post-fracture mortality. A similar relative increase in mortality associated with fracture appears to translate into a larger absolute increase in post-fracture mortality for First Nations compared to non-First Nations peoples. Lower income also predicted increased mortality post-fracture.

Introduction First Nations peoples have a greater risk of mortality than non-First Nations peoples. We examined the independent contributions of First Nations ethnicity and income to mortality post-fracture, and associations with time to surgery post-hip fracture.

Methods Non-traumatic fracture cases and fracture-free controls were identified from population-based administrative data repositories for Manitoba, Canada (aged ≥50 years). Populations were retrospectively matched for sex, age (within 5 years), First Nations ethnicity, and number of comorbidities. Differences in mortality post-fracture of hip, wrist, or spine, 1996–2004 (population 1, n = 63,081), and the hip, 1987–2002(Population 2, n = 41,211) were examined using Cox proportional hazards regression to model time to death. For hip fracture, logistic regression analyses were used to model the probability of death within 30 days and 1 year.

Results Population 1: First Nations ethnicity was associated with an increased mortality risk of 30–53 % for each fracture type. Lower income was associated with an increased mortality risk of 18–26 %. Population 2: lower income predicted mortality overall (odds ratio (OR) 1.15, 95 % confidence interval (CI) 1.07–1.23) and for hip fracture cases (OR 1.18, 95%CI 1.05–1.32), as did older age, male sex, diabetes, and >5 comorbidities (all p ≤ 0.01). Higher mortality was associated with pertrochanteric fracture (OR 1.14, 95 % CI 1.03–1.27), or surgery delay of 2–3 days (OR 1.34, 95 % CI 1.18–1.52) or ≥4 days (OR 2.35, 95 % CI 2.07–2.67).

Conclusion A larger absolute increase in mortality post-fracture was observed for First Nations compared to non-First Nations peoples. Lower income and surgery delay >2 days predicted mortality post-fracture. These data have implications regarding prioritization of healthcare to ensure targeted, timely care for First Nations peoples and/or individuals with lower income.

Glaucoma and on-road driving performance

PURPOSE. To investigate the on-road driving performance of patients with glaucoma.

METHODS. The sample comprised 20 patients with glaucoma and 20 subjects with normal vision, all licensed drivers, matched for age and sex. Driving performance was tested over a 10-km route incorporating 55 standardized maneuvers and skills through residential and business districts of Halifax, Nova Scotia, Canada. Testing was conducted by a professional driving instructor and assessed by an occupational therapist certified in driver rehabilitation, masked to participant group membership and level of vision. Main outcome measures were total number of satisfactory maneuvers and skills, overall rating, and incidence of at-fault critical interventions (application of the dual brake and/or steering override by the driving instructor to prevent a potentially unsafe maneuver). Measures of visual function included visual acuity, contrast sensitivity, and visual fields (Humphrey Field Analyzer; Carl Zeiss Meditec, Inc., Dublin, CA; mean deviation [MD] and binocular Esterman points).

RESULTS. There was no significant difference between patients with glaucoma (mean MD = −1.7 dB [SD 2.2] and −6.5 dB [SD 4.9], better and worse eyes, respectively) and control subjects in total satisfactory maneuvers and skills (P = 0.65), or overall rating (P = 0.60). However, 12 (60%) patients with glaucoma had one or more at-fault critical interventions, compared with 4 (20%) control subjects (odds ratio = 6.00, 95% CI, 1.46–24.69; higher still after adjustment for age, sex, medications and driving exposure), the predominant reason being failure to see and yield to a pedestrian. In the glaucoma group, worse-eye MD was associated with the overall rating of driving (r = 0.66, P = 0.002).

CONCLUSIONS. This sample of patients with glaucoma with slight to moderate visual field impairment performed many real-world driving maneuvers safely. However, they were six times as likely as subjects with normal vision to have a driving instructor intervene for reasons suggesting difficulty with detection of peripheral obstacles and hazards and reaction to unexpected events.

The association between alcohol interventions and Dui incidents in Geelong, Victoria

Introduction and aims : Driving under the influence of alcohol is a major public health problem, every year affecting the lives of billions around the world - and not least in Australia. Since 2001, several Traffic Accident Commission (TAC), police, and community interventions have been implemented in Geelong, Australia to curb drink driving. The current paper aims to assess the impact of 13 alcohol interventions on drink-driving rates in the Geelong region of Australia. The interventions comprised seven TAC media campaigns, three Victoria Police operations, two community interventions targeting licensed premises, and the alcohol interlock program.

Method : This study examined two types of Victoria Police frequency data: Driving under the influence (DUI) offences, and roadside preliminary breath testing (PBT) rates. Multiple regressions were carried out to determine if any of the interventions were significantly associated with frequency fluctuations in the data.

Results : Of the 13 alcohol interventions examined, three TAC campaigns and one Victoria Police operation precipitated significant decreases in drink-driving rates, while another three TAC campaigns were associated with significant increases in drink-driving rates. Over one in five (22.5%) had recorded prior DUI offences.

Conclusions : The most promising approach to curbing DUI-rates in Geelong, appear to be through informative media campaigns which show people specific settings where they might become mildly intoxicated without being aware of it, such as TAC’s ‘Education 1’ campaign. However, there remains a worrying level of recidivist drink drivers in Geelong suggesting the need for tailored approaches.

The effectiveness of health interventions in cardiovascular risk reduction among emergency service personnel

Purpose
The physical demands and hazards associated with emergency service work place particular stress on responders’ cardiovascular systems. Indeed, cardiovascular disease (CVD) is a significant problem for emergency service personnel. Although it may be difficult to alter the cardiovascular health hazards associated with the work environment, it is possible for personnel to control their modifiable CVD risk factors, cardiovascular fitness levels and subsequently, reduce their CVD risk. This review aimed to determine the effectiveness and methodological quality of health interventions designed to mitigate CVD risk in emergency service personnel.

Methods
A literature search of electronic journal databases was performed. Sixteen relevant studies were assessed for methodological quality using a standardised assessment tool. Data regarding the effectiveness of each intervention were extracted and synthesised in a narrative format.

Results
Fifteen studies were rated ‘Weak’ and one study was rated ‘Strong’. Interventions which combined behavioural counselling, exercise and nutrition were more effective in improving cardiovascular health than nutrition, exercise or CVD risk factor assessment-based interventions alone. Further, CVD risk factor assessment in isolation proved to be an ineffective intervention type to reduce CVD risk.

Conclusion
Combined interventions appear most effective in improving the cardiovascular health of emergency service personnel. Accordingly, fire and emergency service agencies should consider trialling multifaceted interventions to improve the cardiovascular health of personnel and avoid interventions focused only on one of nutrition, exercise or CVD risk factor assessment. However, as most studies were methodologically weak, further studies of a higher methodological quality are needed.