Efficient route update and maintenance processes for multipath routing in large-scale industrial wireless sensor networks

Reliable communications is one of the major concerns in wireless sensor networks (WSNs). Multipath routing is an effective way to improve communication reliability in WSNs. However, most of existing multipath routing protocols for sensor networks are reactive and require dynamic route discovery. If there are many sensor nodes from a source to a destination, the route discovery process will create a long end-to-end transmission delay, which causes difficulties in some time-critical applications. To overcome this difficulty, the efficient route update and maintenance processes are proposed in this paper. It aims to limit the amount of routing overhead with two-tier routing architecture and introduce the combination of piggyback and trigger update to replace the periodic update process, which is the main source of unnecessary routing overhead. Simulations are carried out to demonstrate the effectiveness of the proposed processes in improvement of total amount of routing overhead over existing popular routing protocols.

A framework of promoting stakeholder mutual benefits for sustainable housing implementation

Strong regulatory pressure and rising public awareness on environmental issues will continue to influence the market demand for sustainable housing for years to come. Despite this potential, the voluntary uptake rate of sustainable practices is not as high as expected within the new built housing industry. This is in contrast to the influx of emerging building technologies, new materials and innovative designs as showcased in office buildings and exemplar homes worldwide. One of the possible reasons for this under-performance is that key stakeholders such as developers, builders and consumers do not fully understand and appreciate the related challenges, risks and opportunities of pursuing sustainability. Therefore, in their professional and business activities, they may not be able to see the tangible and mutual benefits that sustainable housing may bring. This research investigates the multiple challenges to achieving benefits (CABs) from sustainable housing development, and links these factors to the characteristics of key stakeholders in the housing supply chain. It begins with a comparative survey study among seven stakeholder groups in the Australian housing industry, in order to examine the importance and interrelationships of CABs. In-depth interviews then further explore the survey findings with a focus on stakeholder diversity, which leads to the identification of 12 critical mutual-benefit factors and their interrelationship. Based on such a platform, a mutual-benefit framework is developed with the aid of Interpretive Structure Modelling, to identify the patterns of stakeholder benefit materialisation, suggest the priority of critical factors and provide related stakeholder-specific action guidelines for sustainable housing implementation. The study concludes with a case study of two real-life housing projects to test the application of the mutual-benefit framework for improvement. This framework will lead to a shared value of sustainability among stakeholders and improved stakeholder collaboration, which in turn help to break the "circle of blame" for the current under-performance of sustainable housing implementation.

Improving the efficiency of high power piezoelectric transducers for industrial applications

Most high-power ultrasound applications are driven by two-level inverters. However, the broad spectral content of the two-level pulse results in undesired harmonics that can decrease the performance of the system significantly. On the other hand, it is crucial to excite the piezoelectric devices at their main resonant frequency in order to have maximum energy conversion. Therefore a high-quality, low-distorted power signal is needed to excite the high-power piezoelectric transducer at its resonant frequency. This study proposes an efficient approach to develop the performance of high-power ultrasonic applications using multilevel inverters along with a frequency estimation algorithm. In this method, the resonant frequencies are estimated based on relative minimums of the piezoelectric impedance frequency response. The algorithm follows the resonant frequency variation and adapts the multilevel inverter reference frequency to drive an ultrasound transducer at high power. Extensive simulation and experimental results indicate the effectiveness of the proposed approach.

A proposed Australian industrial control system security curriculum

The security of industrial control systems in critical infrastructure is a concern for the Australian government and other nations. There is a need to provide local Australian training and education for both control system engineers and information technology professionals. This paper proposes a postgraduate curriculum of four courses to provide knowledge and skills to protect critical infrastructure industrial control systems. Our curriculum is unique in that it provides security awareness but also the advanced skills required for security specialists in this area. We are aware that in the Australian context there is a cultural gap between the thinking of control system engineers who are responsible for maintaining and designing critical infrastructure and information technology professionals who are responsible for protecting these systems from cyber attacks. Our curriculum aims to bridge this gap by providing theoretical and practical exercises that will raise the awareness and preparedness of both groups of professionals.

Rebuilding housing after a disaster : factors for failure

Unlike most normal construction projects, post-disaster housing projects are diverse in nature, have unique socio-cultural and economical requirements, and are extremely dynamic and thus necessitate a meaningful and dynamic response. Post-disaster reconstruction practices that lack a strategy compatible with the severity of disaster, community culture, socio-economic requirements, environmental condition, government legislations, and technical and technological situations, often fail to operate and respond effectively to the needs of the wider affected population. Factors that frequently pose real threats to the eventual success of reconstruction projects are rarely given appropriate consideration when designing such projects. Research into past reconstruction practices has shown that ignoring these factors altogether or failing to give them meaningful consideration can affect housing reconstruction projects. In other words, they either miss their targets altogether or undergo serious modifications after their occupancy, subsequently resulting in an overall loss of project resources. This article touches upon the common factors that negatively impact the outcome of such projects.

Critical factors for successful housing reconstruction projects following a major disaster

Post–disaster reconstruction projects are often considered ineffectual or unproductive because on many occasions in the past they have performed extremely poorly during post-contract occupation, or have failed altogether to deliver acceptable outcomes. In some cases, these projects have already failed even before their completion, leading many sponsor aid organisations to hold these projects up as examples of how not to deliver housing reconstruction. Research into some previous unsuccessful projects has revealed that often the lack of adequate knowledge regarding the context and complexity involved in the implementation of these projects is generally responsible for their failure. Post-disaster reconstruction projects are certainly very complex in nature, often very context-specific and they can vary widely in magnitude. Despite such complexity, reconstruction projects can still have a high likelihood of success if adequate consideration is given to the importance of factors which are known to positively influence reconstruction efforts. Good outcomes can be achieved when planners and practitioners ensure best practices are embedded in the design of reconstruction projects at the time reconstruction projects they are first instigated. This paper outlines and discusses factors that significantly contribute to the successful delivery of post-disaster housing reconstruction projects.

Getting in the door : the voluntary provision of accessible housing in Australia

This paper outlines the methodology used in a PhD qualitative research study on the agency of the housing industry in Australia in the provision of accessible housing. Previous studies have identified the need for an increased supply of accessible housing to optimise the inclusion and participation of all people, yet the demand for accessible housing by new home buyers is minimal and voluntary strategies to increase supply have typically failed. In 2010, housing industry leaders agreed to adopt a national voluntary access guideline for housing (Livable Housing Design) and a strategy to provide minimum access features in all new housing by 2020. This study explores the “escaped” phenomenon; how individual agents within the housing industry respond to such initiatives. As the paper is written mid-study it uses a preliminary theme in the findings, that is, minimal demand, to illustrate the methodology of the research.

A comprehensive dual-scale wood torrefaction model : application to the analysis of thermal run-away in industrial heat treatment processes

A dual-scale model of the torrefaction of wood was developed and used to study industrial configurations. At the local scale, the computational code solves the coupled heat and mass transfer and the thermal degradation mechanisms of the wood components. At the global scale, the two-way coupling between the boards and the stack channels is treated as an integral component of the process. This model is used to investigate the effect of the stack configuration on the heat treatment of the boards. The simulations highlight that the exothermic reactions occurring in each single board can be accumulated along the stack. This phenomenon may result in a dramatic eterogeneity of the process and poses a serious risk of thermal runaway, which is often observed in industrial plants. The model is used to explain how thermal runaway can be lowered by increasing the airflow velocity, the sticker thickness or by gas flow reversal.

Sustainable and affordable housing : a myth or reality

The Australian government has released a draft National Building Framework that will likely tighten the building standard for new houses to meet higher sustainability requirements. There are uncertainties about the impact this could have on the cost of housing and the supply of affordable housing. This paper aims to provide evidence-based conclusions on the possibility of delivering sustainable and affordable housing for low income people. The case studies are gathered from Brisbane and Gold Coast. Case studies are analysed by unpacking the features that were included to meet sustainability and affordability goals for housing. This paper outlines the key factors for their success and also challenges for replication of the projects. The study shows that the key success drivers for delivering sustainable and affordable housing are providing planning incentives, subsidies for increased energy efficiency, supportive regulatory frameworks and appropriate allocation of infrastructure charges. It shows that government can prioritise their resources to support affordable and sustainable housing for low income people.

Integration of Saudi Arabia’s conservative Islamic culture in sustainable housing design

The cities of Saudi Arabia have perhaps the largest growth rates of cities in the Middle East, such that it has become a cause in shortage of housing for mid and low-income families, as is the case in other developing countries. Even when housing is found, it is not sustainable nor is it providing the cultural needs of those families. The aim of this paper is to integrate the unique conservative Islamic Saudi culture into the design of sustainable housing. This paper is part of a preliminary study of an on-going PhD thesis, which utilises a semistructured interview of a panel of nine experts in collecting the data. The interviews consisted of ten questions ranging from general questions such as stating their expertise and work position to more specific question such as listing the critical success factors and/or barriers for applying sustainability to housing in Saudi Arabia. Since the participants were selected according to their experience, the answers to the interview questions were satisfactory where the generation of the survey questions for the second stage in the PhD thesis took place after analysing the participant’s answers to the interview questions. This paper recommends design requirements for accommodating the conservative Islamic Saudi Culture in low cost sustainable houses. Such requirements include achieving privacy through the use of various types of traditional Saudi architectural elements, such as the method of decorative screening of windows, called Mashrabiya, and having an inner courtyard where the house looks inward rather than outward. Other requirements include educating firms on how to design sustainable housing, educating the public on the advantages of sustainable housing and implementing new laws that enforce the utilisation of sustainable methods to housing construction. This paper contributes towards the body of knowledge by proposing initial findings on how to integrate the conservative Islamic culture of Saudi Arabia into the design of a sustainable house specifically for mid and low-income families. This contribution can be implemented on developing countries in the region that are faced with housing shortage for mid and low-income families.

Analysis of the design-construction supply chain in the thermal performance of sub-tropical and tropical housing

Background: In sub-tropical and tropical Queensland, a legacy of poor housing design,minimal building regulations with few compliance measures, an absence of post-construction performance evaluation and various social and market factors has led to a high and growing penetration of, and reliance on, air conditioners to provide thermal comfort for occupants. The pervasive reliance on air conditioners has arguably impacted on building forms, changed cultural expectations of comfort and social practices for achieving comfort, and may have resulted in a loss of skills in designing and constructing high performance building envelopes. Aim: The aim of this paper is to report on initial outcomes of a project that sought to determine how the predicted building thermal performance of twenty-five houses in subtropical and tropical Queensland compared with objective performance measures and comfort performance as perceived by occupants. The purpose of the project was to shed light on the role of various supply chain agents in the realisation of thermal performance outcomes. Methodology: The case study methodology embraced a socio-technical approach incorporating building science and sociology. Building simulation was used to model thermal performance under controlled comfort assumptions and adaptive comfort conditions. Actual indoor climate conditions were measured by temperature and relative humidity sensors placed throughout each house, whilst occupants’ expectations of thermal comfort and their self-reported behaviours were gathered through semi-structured interviews and periodic comfort surveys. Thermal imaging and air infiltration tests, along with building design documents, were analysed to evaluate the influence of various supply chain agents on the actual performance outcomes. Results: The results clearly show that in the housing supply chain – from designer to constructor to occupant – there is limited understanding from each agent of their role in contributing to, or inhibiting, occupants’ comfort.

Factors influencing sustainability outcomes of housing in subtropical Australia

Purpose: The challenges of providing housing that sustains its inhabitants socially, economically and environmentally, and is inherently sustainable for the planet as a whole, requires a holistic systems approach that considers the product, the supply chain and the market, as well as the inter-dependencies within and between each of these process points. The purpose of the research is to identify factors that impact the sustainability performance outcomes of residential dwellings and the diffusion of sustainable housing into the mainstream housing market. Design/methodology/approach: This research represents a snapshot in time: a recording of the experiences of seven Australian families who are “early adopters” of leading edge sustainable homes within a specific sustainable urban development in subtropical Queensland. The research adopts a qualitative approach to compare the goals and expectations of these families with the actual sustainability aspects incorporated into their homes and lifestyles. Findings: The results show that the “product” – a sustainable house – is difficult to define; that sustainability outcomes were strongly influenced by individual concerns and the contextual urban environment; and that economic comparisons with “standard” housing are challenging. Research limitations/implications: This qualitative study is based on seven families (13 individuals) in an Ecovillage in southeast Queensland. Although the findings make a significant contribution to knowledge, they may not be generalisable to the wider population. Originality/value: The experiences of these early adopter families suggest that the housing market and regulators play critical roles, through actions and language, in limiting or enhancing the diffusion of sustainable housing into the market.

Industrial land price and its impact on urban growth : a Chinese case study

China is experiencing rapid progress in industrialization, with its own rationale toward industrial land development based on a deliberate change from an extensive to intensive form of urban land use. One result has been concerted attempts by local government to attract foreign investment by a low industrial land price strategy, which has resulted in a disproportionally large amount of industrial land within the total urban land use structure at the expense of the urban sprawl of many cities. This paper first examines “Comparable Benchmark Price as Residential land use” (CBPR) as the theoretical basis of the low industrial land price phenomenon. Empirical findings are presented from a case study based on data from Jinyun County, China. These data are analyzed to reveal the rationale of industrial land price from 2000 to 2010 concerning the CBPR model. We then explore the causes of low industrial land prices in the form of a “Centipede Game Model”, involving two neighborhood regions as “major players” to make a set of moves (or strategies). When one of the players unilaterally reduces the land price to attract investment with the aim to maximize profits arising from the revenues generated from foreign investment and land premiums, a two-player price war begins in the form of a dynamic game, the effect of which is to produce a downward spiral of prices. In this context, the paradox of maximizing profits for each of the two players are not accomplished due to the inter-regional competition of attracted investment leading to a lose-lose situation for both sides’ in competing for land premium revenues. A short-term solution to the problem is offered involving the establishment of inter-regional cooperative partnerships. For the longer term, however, a comprehensive reform of the local financial system, more adroit regional planning and an improved means of evaluating government performance is needed to ensure the government's role in securing pubic goods is not abandoned in favor of one solely concerned with revenue generation.

High frequency high power converters for industrial applications

The main contribution of this project was to investigate power electronics technology in designing and developing high frequency high power converters for industrial applications. Therefore, the research was conducted at two levels; first at system level which mainly encapsulated the circuit topology and control scheme and second at application level which involves with real-world applications. Pursuing these objectives, varied topologies have been developed and proposed within this research. The main aim was to resolving solid-state switches limited power rating and operating speed while increasing the system flexibility considering the application characteristics. The developed new power converter configurations were applied to pulsed power and high power ultrasound applications for experimental validation.

Inclusive housing in Australia : a question of responsibility and distributive justice

This thesis challenged the assumption that the Australian housing industry will voluntarily and independently transform its practices to build inclusive communities. Through its focus on perceptions of responsibility and the development of a theoretical framework for voluntary initiatives, the thesis offers key stakeholders and advocates a way to work towards the provision of inclusive housing as an instrument of distributive justice.