Showing papers by "Queensland University of Technology published in 2008"

Epidemiology of basal-like breast cancer

Abstract: Risk factors for the newly identified “intrinsic” breast cancer subtypes (luminal A, luminal B, basal-like and human epidermal growth factor receptor 2-positive/estrogen receptor-negative) were determined in the Carolina Breast Cancer Study, a population-based, case–control study of African-American and white women. Immunohistochemical markers were used to subtype 1,424 cases of invasive and in situ breast cancer, and case subtypes were compared to 2,022 controls. Luminal A, the most common subtype, exhibited risk factors typically reported for breast cancer in previous studies, including inverse associations for increased parity and younger age at first full-term pregnancy. Basal-like cases exhibited several associations that were opposite to those observed for luminal A, including increased risk for parity and younger age at first term full-term pregnancy. Longer duration breastfeeding, increasing number of children breastfed, and increasing number of months breastfeeding per child were each associated with reduced risk of basal-like breast cancer, but not luminal A. Women with multiple live births who did not breastfeed and women who used medications to suppress lactation were at increased risk of basal-like, but not luminal A, breast cancer. Elevated waist-hip ratio was associated with increased risk of luminal A in postmenopausal women, and increased risk of basal-like breast cancer in pre- and postmenopausal women. The prevalence of basal-like breast cancer was highest among premenopausal African-American women, who also showed the highest prevalence of basal-like risk factors. Among younger African-American women, we estimate that up to 68% of basal-like breast cancer could be prevented by promoting breastfeeding and reducing abdominal adiposity.

Re-conceptualizing Information System Success: The IS-Impact Measurement Model *

Abstract: This paper re-conceptualizes 'information system success' as a formative, multidimensional index. A validated and widely accepted such index would facilitate cumulative research on the impacts of IS, while at the same time providing a benchmark for organizations to track their IS performance. The proposed IS-Impact measurement model represents the stream of net benefits from an Information System (IS), to date and anticipated, as perceived by all key-user-groups. Model measures are formulated to be robust, economical and simple, yielding results that are comparable across diverse systems and contexts, and from multiple user perspectives. The model includes 4 dimensions in two halves. The 'impact' half measures benefits to date, or Individual- and Organizational-Impact; the 'quality' half, uses System-Quality and Information-Quality as proxies for probable future impacts. Study findings evidence the necessity, additivity and completeness of these four dimensions. The validation study involved three separate surveys, including exploratory and confirmatory phases preceded by an identification-survey. Content analysis of 485 qualitative 'impacts' cited by 137 respondents from across 27 Australian Government Agencies that implemented SAP Financials in the late 90's, identified salient dimensions and measures. The resultant a-priori model ('pool' of 37 measures) was operationalized in the subsequent specification-survey, yielding 310 responses across the same 27 agencies. The confirmation-survey, employing 27 validated measures from the specification-survey, was next conducted in a large university that had implemented ORACLE Financials. Confirmatory analysis of the 153 responses provides further strong evidence of model validity.

Semantics and analysis of business process models in BPMN

Abstract: The Business Process Modelling Notation (BPMN) is a standard for capturing business processes in the early phases of systems development. The mix of constructs found in BPMN makes it possible to create models with semantic errors. Such errors are especially serious, because errors in the early phases of systems development are among the most costly and hardest to correct. The ability to statically check the semantic correctness of models is thus a desirable feature for modelling tools based on BPMN. Accordingly, this paper proposes a mapping from BPMN to a formal language, namely Petri nets, for which efficient analysis techniques are available. The proposed mapping has been implemented as a tool that, in conjunction with existing Petri net-based tools, enables the static analysis of BPMN models. The formalisation also led to the identification of deficiencies in the BPMN standard specification.

What skills and attributes does an accounting graduate need? Evidence from student perceptions and employer expectations

Abstract: For some years there has been much debate between various stakeholders about the need for accounting graduates to develop a broader set of skills to be able to pursue a career in the accounting profession. This study uses mixed methods to examine perceptions and expectations of two major stakeholders: students and employers. Findings indicate that students are becoming aware of employers’ expectations in terms of communication, analytical, professional and teamwork skills. While employers are still expecting a good understanding of basic accounting skills and strong analytical skills, they are also requiring ‘business awareness’ and knowledge in terms of the ‘real world’. Both students and employers report that many of the ‘essential’ non technical and professional skills and attributes are not being developed sufficiently in university accounting programs.

Modeling the Price Dynamics of Co2 Emission Allowances

Abstract: In this paper we analyze the short-term spot price behavior of carbon dioxide (CO2) emission allowances of the new EU-wide CO2 emissions trading system (EU-ETS). After reviewing the stylized facts of this new class of assets we investigate several approaches for modeling the returns of emission allowances. Due to the different phases of price and volatility behavior in the returns, we suggest the use of Markov switching and AR-GARCH models for stochastic modeling. We examine the approaches by conducting an in-sample and out-of-sample forecasting analysis and by comparing the results to alternative approaches. Our findings strongly support the adequacy of the models capturing characteristics like skewness, excess kurtosis and in particular different phases of volatility behavior in the returns.

Social network markets: a new definition of the creative industries

Abstract: We propose a new definition of the creative industries in terms of social network markets The extant definition of the creative industries is based on an industrial classification that proceeds in terms of the creative nature of inputs and the intellectual property nature of outputs We propose, instead, a new market-based definition in terms of the extent to which both demand and supply operate in complex social networks We review and critique the standard creative industries definitions and explain why we believe a market-based social network definition offers analytic advance We discuss some empirical, analytic and policy implications of this new definition

Toward improving the relevance of information systems research to practice: the role of applicability checks

Abstract: This paper takes a first step in aiding researchers to improve the relevance of their research to practice. By proposing that Information Systems researchers conduct applicability checks with practitioners on the research objects (for example, theories, models, frameworks, processes, technical artifacts, or other theoretically based IS artifacts) they either produce or use in theory-focused research, our paper presents an actionable, systematic approach to evaluating, establishing, and further improving research relevance. Furthermore, because it is an approach that can be conducted as an additional step either at the beginning or the end of the traditional research life cycle, it leaves untouched the rigorous methods used to conduct the study, that is, it does not compromise traditional research models. The approach we propose is based on the analyses of three dimensions of relevance that are critical to practitioners' attempts to internalize IS research findings (importance, accessibility, and suitability), and a comprehensive set of solutions that can be used to address them. Our analysis reveals that the most critical dimension for practice is the importance of the research to the needs of practice. The solution we propose to address that need is to conduct an applicability check on the research objects of interest. The applicability check forms an integral part of the research process, either prior to or following engagement in a typical research process. We present principles and criteria for the conduct and evaluation of an applicability check, which is primarily based on the focus group method, and secondarily on a modified nominal group technique.

Personality and Self-Esteem as Predictors of Young People's Technology Use

Abstract: We examined the role of personality and self-esteem in university students' (N = 200) use of communication technologies. More disagreeable individuals spent increased time on calls, whereas extraverted and neurotic individuals reported increased time spent text messaging. More disagreeable individuals and those with lower self-esteem spent increased time using instant messaging (IM). For addictive tendencies related to communication technologies, more neurotic individuals reported stronger mobile phone addictive tendencies, while more disagreeable individuals and those with lower self-esteem reported stronger IM addictive tendencies.

Determining the informational, navigational, and transactional intent of Web queries

Abstract: In this paper, we define and present a comprehensive classification of user intent for Web searching. The classification consists of three hierarchical levels of informational, navigational, and transactional intent. After deriving attributes of each, we then developed a software application that automatically classified queries using a Web search engine log of over a million and a half queries submitted by several hundred thousand users. Our findings show that more than 80% of Web queries are informational in nature, with about 10% each being navigational and transactional. In order to validate the accuracy of our algorithm, we manually coded 400 queries and compared the results from this manual classification to the results determined by the automated method. This comparison showed that the automatic classification has an accuracy of 74%. Of the remaining 25% of the queries, the user intent is vague or multi-faceted, pointing to the need for probabilistic classification. We discuss how search engines can use knowledge of user intent to provide more targeted and relevant results in Web searching.

Lymphedema After Breast Cancer: Incidence, Risk Factors, and Effect on Upper Body Function

Abstract: Purpose Secondary lymphedema is associated with adverse physical and psychosocial consequences among women with breast cancer (BC). This article describes the prevalence and incidence of lymphedema between 6 and 18 months after BC treatment; personal, treatment, and behavioral correlates of lymphedema status; and the presence of other upper-body symptoms (UBS) and function (UBF). Patients and Methods A population-based sample of Australian women (n = 287) with recently diagnosed, invasive BC were evaluated on five occasions using bioimpedance spectroscopy. Lymphedema was diagnosed when the ratio of impedance values, comparing treated and untreated sides, was three standard deviations more than normative data. UBF was assessed using the validated Disability of the Arm, Shoulder, and Hand questionnaire. Results From 6 to 18 months after surgery, 33% (n = 62) of the sample were classified as having lymphedema; of these, 40% had long-term lymphedema. Although older age, more extensive surgery or axillary node...

Visible-Light-Driven Oxidation of Organic Contaminants in Air with Gold Nanoparticle Catalysts on Oxide Supports

Abstract: One of the great challenges in catalysis is to devise new catalysts that have high activity when illuminated by visible light. Solving this challenge will allow us to use sunlight, an abundant and clean low-cost energy source, to drive chemical reactions. Visible light (wavelength l> 400 nm) constitutes around 43% of solar energy, and the energy of sunlight to the Earth is about 10000 times more than the current energy consumption of the world. Many approaches have been proposed to develop visible light photocatalysts, including doping TiO2 with metal ions or metal atom clusters, [4,5] incorporating nitrogen and carbon into TiO2, and employing other metal oxides or polymetallates as catalyst materials. 5,8] Research has been mainly concentrated on semiconductor oxides. Sulfides have also been studied, but they are not suitable catalysts because of their poor chemical stability. However, searching for catalysts that can work under visible light should not be limited to semiconductor materials with band-gap structure, but can be extended to other materials, such as gold nanoparticles. It can be said that glaziers in medieval forges were the first nanotechnologists who produced colors with gold nanoparticles of different sizes, although they had little understanding of the modern day principles which have become a hot topic in the last two decades. In recent years there have been numerous studies on the optical properties of gold nanoparticles. Gold nanoparticles absorb visible light intensely because of the surface plasmon resonance (SPR) effect. The electromagnetic field of incident light couples with the oscillations of conduction electrons in gold particles, resulting in strong-field enhancement of the local electromagnetic fields near the rough surface of gold nanoparticles. The enhanced local field strength can be over 500 times larger than the applied field for structures with sharp apices, edges, or concave curvature (e.g. nanowires, cubes, triangular plates, and nanoparticle junctions). The SPR absorption may cause rapid heating of the nanoparticles. Gold nanoparticles supported on metal oxides are efficient catalysts for important oxidation process, including selective oxidation of hydrocarbons and oxidation of various volatile organic compounds (VOCs), such as CO, CH3OH, and HCHO at moderately elevated temperatures. Therefore, the combination of the SPR absorption and the catalytic activity of gold nanoparticles presents an important opportunity: if the heated gold nanoparticles could activate the organic molecules on them to induce oxidation of the organic compounds, then oxidation on gold catalysts can be driven by visible light at ambient temperature. Moreover, the SPR is a local effect, limited to the noble metal particles, so that the light only heats gold nanoparticles, which generally account for a few percent of the overall catalyst mass. This leads to significant saving in energy consumption for catalyzing organic compound oxidation. To verify the possibility of driving the VOC oxidation with visible light at room temperature, we prepared gold particles supported on various oxide powders. ZrO2 and SiO2 powders were first chosen as supports, because their band gaps are circa 5.0 eV and circa 9.0 eV, respectively, which are much larger than the energies of the photons of visible light (less than 3.0 eV). Thus, the light cannot excite electrons from the valence band to the conduction band. It is also impossible for the gold nanoparticles on ZrO2 to reduce the band gaps of ZrO2 enough for visible light photons to be absorbed and excite electrons in ZrO2. Thus, the catalytic activity is not caused by the same mechanism as occurs in semiconductor photocatalysts, but is due to the SPR effect of gold nanoparticles. The changes in the concentrations of the reactant (HCHO, 100 ppm) and product (CO2), when gold supported on ZrO2 was used as the catalyst, are depicted in Figure 1a. The initial concentration of HCHO in the glass vessel was 100 ppm. HCHO content decreased by 64% in two hours under the irradiation of six light tubes of blue light (with wavelength between 400 and 500 nm and the irradiation energy determined to be 0.17 Wcm 2 at the position of glass slides coated with the gold catalysts), and the CO2 content in the vessel increased accordingly. These results confirm that the oxidation of formaldehyde to carbon dioxide proceeds to a large extent at ambient temperature. The turnover frequency was calculated as being about 1.2 = 10 3 molecules of [*] Dr. X. Chen, Prof. H.-Y. Zhu, Z.-F. Zheng School of Physical and Chemical Sciences Queensland University of Technology Brisbane, Qld 4001 (Australia) Fax: (+61)7-3864-1804 E-mail: hy.zhu@qut.edu.au

Dynamics of in vitro polymer degradation of polycaprolactone-based scaffolds: accelerated versus simulated physiological conditions.

Abstract: The increasing use of biodegradable devices in tissue engineering and regenerative medicine means it is essential to study and understand their degradation behaviour. Accelerated degradation systems aim to achieve similar degradation profiles within a shorter period of time, compared with standard conditions. However, these conditions only partially mimic the actual situation, and subsequent analyses and derived mechanisms must be treated with caution and should always be supported by actual long-term degradation data obtained under physiological conditions. Our studies revealed that polycaprolactone (PCL) and PCL-composite scaffolds degrade very differently under these different degradation conditions, whilst still undergoing hydrolysis. Molecular weight and mass loss results differ due to the different degradation pathways followed (surface degradation pathway for accelerated conditions and bulk degradation pathway for simulated physiological conditions). Crystallinity studies revealed similar patterns of recrystallization dynamics, and mechanical data indicated that the scaffolds retained their functional stability, in both instances, over the course of degradation. Ultimately, polymer degradation was shown to be chiefly governed by molecular weight, crystallinity susceptibility to hydrolysis and device architecture considerations whilst maintaining its thermodynamic equilibrium.

Marginal likelihood estimation via power posteriors

Abstract: Model choice plays an increasingly important role in statistics. From a Bayesian perspective a crucial goal is to compute the marginal likelihood of the data for a given model. However, this is typically a difficult task since it amounts to integrating over all model parameters. The aim of the paper is to illustrate how this may be achieved by using ideas from thermodynamic integration or path sampling. We show how the marginal likelihood can be computed via Markov chain Monte Carlo methods on modified posterior distributions for each model. This then allows Bayes factors or posterior model probabilities to be calculated. We show that this approach requires very little tuning and is straightforward to implement. The new method is illustrated in a variety of challenging statistical settings.

How Much Language Is Enough? Theoretical and Practical Use of the Business Process Modeling Notation

Abstract: The Business Process Modeling Notation (BPMN) is an increasingly important industry standard for the graphical representation of business processes. BPMN offers a wide range of modeling constructs, significantly more than other popular languages. However, not all of these constructs are equally important in practice as business analysts frequently use arbitrary subsets of BPMN. In this paper we investigate what these subsets are, and how they differ between academic, consulting, and general use of the language. We analyzed 120 BPMN diagrams using mathematical and statistical techniques. Our findings indicate that BPMN is used in groups of several, well-defined construct clusters, but less than 20% of its vocabulary is regularly used and some constructs did not occur in any of the models we analyzed. While the average model contains just 9 different BPMN constructs, models of this complexity have typically just 4-5 constructs in common, which means that only a small agreed subset of BPMN has emerged. Our findings have implications for the entire ecosystems of analysts and modelers in that they provide guidance on how to reduce language complexity, which should increase the ease and speed of process modeling.

Female Presence on Corporate Boards: A Multi-Country Study of Environmental Context

Abstract: A growing body of ethics research investigates gender diversity and governance on corporate boards, at individual and firm levels, in single country studies. In this study, we explore the environmental context of female representation on corporate boards of directors, using data from 43 countries. We suggest that women’s representation on corporate boards may be shaped by the larger environment, including the social, political and economic structures of individual countries. We use logit regression to conduct our analysis. Our results indicate that countries with higher representation of women on boards are more likely to have women in senior management and more equal ratios of male to female pay. However, we find that countries with a longer tradition of women’s political representation are less likely to have high levels of female board representation.

Soundness of workflow nets : classification, decidability, and analysis

Abstract: Workflow nets, a particular class of Petri nets, have become one of the standard ways to model and analyze workflows. Typically, they are used as an abstraction of the workflow that is used to check the so-called soundness property. This property guarantees the absence of livelocks, deadlocks, and other anomalies that can be detected without domain knowledge. Several authors have proposed alternative notions of soundness and have suggested to use more expressive languages, e.g., models with cancellations or priorities. This paper provides an overview of the different notions of soundness and investigates these in the presence of different extensions of workflow nets. We will show that the eight soundness notions described in the literature are decidable for workflow nets. However, most extensions will make all of these notions undecidable. These new results show the theoretical limits of workflow verification. Moreover, we discuss some of the analysis approaches described in the literature.

Confinement and propagation characteristics of subwavelength plasmonic modes

Abstract: We have studied subwavelength confinement of the surface plasmon polariton modes of various plasmonic waveguides and examined their relative merits using a graphical parametric representation of their confinement and propagation characteristics. While the same plasmonic phenomenon governs mode confinement in all these waveguides, the various architectures can exhibit distinctive behavior in terms of effective mode area and propagation distance. We found that the waveguides based on metal and one dielectric material show a similar trade-off between energy confinement and propagation distance. However, a hybrid plasmon waveguide, incorporating metal, low index and high index dielectric materials, exhibits longer propagation distances for the same degree of confinement. We also point out that plasmonic waveguides with sharp features can provide an extremely strong local field enhancement, which is not necessarily accompanied by strong confinement of the total electromagnetic energy. In these waveguides, a mode may couple strongly to nearby atoms, but suffer relatively low propagation losses due to weak confinement.

An empirical survey of residential water demand modelling

Abstract: The increased reliance on demand-side management policies as an urban water consumption management tool has stimulated considerable debate among economists, water utility managers, regulators, consumer interest groups and policymakers. In turn, this has fostered an increasing volume of literature aimed at providing best-practice estimates of price and income elasticities, quantifying the impact of non-price water restrictions and gauging the impact of non-discretionary environmental factors affecting residential water demand. This paper provides a synoptic survey of empirical residential water demand analyses conducted in the last 25 years. Both model specification and estimation and the outcomes of the analyses are discussed.

An Illusory Interiority: Interrogating the discourse/s of inclusion

Abstract: It is generally accepted that the notion of inclusion derived or evolved from the practices of mainstreaming or integrating students with disabilities into regular schools. Halting the practice of segregating children with disabilities was a progressive social movement. The value of this achievement is not in dispute. However, our charter as scholars and cultural vigilantes (Slee & Allan, 2001) is to always look for how we can improve things; to avoid stasis and complacency we must continue to ask, how can we do it better? Thus, we must ask ourselves uncomfortable questions and develop a critical perspective that Foucault characterised as an ‘ethic of discomfort’ (Rabinow & Rose, 2003, p. xxvi) by following the Nietzschean principle where one acts ‘counter to our time and thereby on our time ... for the benefit of a time to come’ (Nietzsche, 1874, p. 60 in Rabinow & Rose, 2003, p. xxvi). This paper begins with a fundamental question for those participating in inclusive education research and scholarship—when we talk of including, into what do we seek to include?

The electrical properties of polymer nanocomposites with carbon nanotube fillers

Abstract: The electrical properties of polymer nanocomposites containing a small amount of carbon nanotube (CNT) are remarkably superior to those of conventional electronic composites. Based on three-dimensional (3D) statistical percolation and 3D resistor network modeling, the electrical properties of CNT nanocomposites, at and after percolation, were successfully predicted in this work. The numerical analysis was also extended to investigate the effects of the aspect ratio, the electrical conductivity, the aggregation and the shape of CNTs on the electrical properties of the nanocomposites. A simple empirical model was also established based on present numerical simulations to predict the electrical conductivity in several electronic composites with various fillers. This investigation further highlighted the importance of theoretical and numerical analyses in the exploration of basic physical phenomena, such as percolation and conductivity in novel nanocomposites.

Morphology−Function Relationship of ZnO: Polar Planes, Oxygen Vacancies, and Activity

Abstract: The relationship between morphology and function of ZnO is demonstrated by investigating its polar planes, oxygen vacancies, and catalytic activity for N-formylation. ZnO with various morphologies is controllably synthesized via simple hydrothermal reactions. Scanning electron microcopy images exhibit a variety of the as-prepared hexagonal zinc oxides: rods, disks, rings, and screw caps as a new member of ZnO morphology family. Each of the morphologies is remarkably different from the others in the proportion of the (0001) and (0001) polar planes in the outside surfaces of ZnO crystals. The analysis of photoluminescence spectra shows that there exist more oxygen vacancies in the samples with large polar planes. The synthesized samples are used as a catalyst for the N-formylation of aniline and show a morphology-dependent activity: ZnO with large polar planes is more catalytically active for the N-formylation reaction. This is attributed to the fact that the polar planes generate easily oxygen vacancies, ...

Measuring Similarity between Business Process Models

Abstract: Quality aspects become increasingly important when business process modeling is used in a large-scale enterprise setting. In order to facilitate a storage without redundancy and an efficient retrieval of relevant process models in model databases it is required to develop a theoretical understanding of how a degree of behavioral similarity can be defined. In this paper we address this challenge in a novel way. We use causal footprintsas an abstract representation of the behavior captured by a process model, since they allow us to compare models defined in both formal modeling languages like Petri nets and informal ones like EPCs. Based on the causal footprint derived from two models we calculate their similarity based on the established vector space model from information retrieval. We validate this concept with an experiment using the SAP Reference Model and an implementation in the ProM framework.

The electrical properties of polymer nanocomposites with carbon nanotube fillers

Abstract: The electrical properties of polymer nanocomposites containing a small amount of carbon nanotube (CNT) are remarkably superior to those of conventional electronic composites. Based on three-dimensional (3D) statistical percolation and 3D resistor network modeling, the electrical properties of CNT nanocomposites, at and after percolation, were successfully predicted in this work. The numerical analysis was also extended to investigate the effects of the aspect ratio, the electrical conductivity, the aggregation and the shape of CNTs on the electrical properties of the nanocomposites. A simple empirical model was also established based on present numerical simulations to predict the electrical conductivity in several electronic composites with various fillers. This investigation further highlighted the importance of theoretical and numerical analyses in the exploration of basic physical phenomena, such as percolation and conductivity in novel nanocomposites.