Uncertainty analysis of pollutant build-up modelling based on a Bayesian Weighted Least Squares approach

Reliable pollutant build-up prediction plays a critical role in the accuracy of urban stormwater quality modelling outcomes. However, water quality data collection is resource demanding compared to streamflow data monitoring, where a greater quantity of data is generally available. Consequently, available water quality data sets span only relatively short time scales unlike water quantity data. Therefore, the ability to take due consideration of the variability associated with pollutant processes and natural phenomena is constrained. This in turn gives rise to uncertainty in the modelling outcomes as research has shown that pollutant loadings on catchment surfaces and rainfall within an area can vary considerably over space and time scales. Therefore, the assessment of model uncertainty is an essential element of informed decision making in urban stormwater management. This paper presents the application of a range of regression approaches such as ordinary least squares regression, weighted least squares Regression and Bayesian Weighted Least Squares Regression for the estimation of uncertainty associated with pollutant build-up prediction using limited data sets. The study outcomes confirmed that the use of ordinary least squares regression with fixed model inputs and limited observational data may not provide realistic estimates. The stochastic nature of the dependent and independent variables need to be taken into consideration in pollutant build-up prediction. It was found that the use of the Bayesian approach along with the Monte Carlo simulation technique provides a powerful tool, which attempts to make the best use of the available knowledge in the prediction and thereby presents a practical solution to counteract the limitations which are otherwise imposed on water quality modelling.

Small signal stability analysis of a DFIG based wind power system with tuned damping controller under super/sub-synchronous mode of operation

This paper focuses on the super/sub-synchronous operation of the doubly fed induction generator (DFIG) system. The impact of a damping controller on the different modes of operation for the DFIG based wind generation system is investigated. The co-ordinated tuning of the damping controller to enhance the damping of the oscillatory modes using bacteria foraging (BF) technique is presented. The results from eigenvalue analysis are presented to elucidate the effectiveness of the tuned damping controller in the DFIG system. The robustness issue of the damping controller is also investigated

Active and reactive power control of synchronous generator for the realization of a virtual power plant

This paper presents a novel power control strategy that decouples the active and reactive power for a synchronous generator connected to a power network. The proposed control paradigm considers the capacitance of the transmission line along with its resistance and reactance as-well. Moreover the proposed controller takes into account all cases of R-X relationships, thus allowing it to function in Virtual Power Plant (VPP) structures which operate at both medium voltage (MV) and low voltage (LV) levels. The independent control of active and reactive power is achieved through rotational transformations of the terminal voltages and currents at the synchronous generator's output. This paper details the control technique by first presenting the mathematical and electrical network analysis of the methodology and then successfully implementing the control using MATLAB-SIMULINK simulation.

Modeling as a bridge between real world problems and school mathematics

This article argues for an interdisciplinary approach to mathematical problem solving at the elementary school, one that draws upon the engineering domain. A modeling approach, using engineering model eliciting activities, might provide a rich source of meaningful situations that capitalize on and extend students’ existing mathematical learning. The study reports on the developments of 48 twelve-year old students who worked on the Bridge Design activity. Results revealed that young students, even before formal instruction, have the capacity to deal with complex interdisciplinary problems. A number of students created quite appropriate models by developing the necessary mathematical constructs to solve the problem. Students’ difficulties in mathematizing the problem, and in revising and documenting their models are presented and analysed, followed by a discussion on the appropriateness of a modeling approach as a means for introducing complex problems to elementary school students.

The development of a model to measure destination brand performance across travel contexts

The field of destination image has been widely discussed in the destination literature since the early 1970s (see Mayo, 1973). However the extent to which travel context impacts on an individual’s destination image evaluation, and therefore destination choice, has received scant attention (Hu & Ritchie, 1993). This study, utilising expectancy-value theory, sought to elicit salient destination attributes from consumers across two travel contexts: short-break holidays and longer getaways. Using the Repertory Test technique, attributes elicited as being salient for short-break holidays were consistent with those elicited for longer getaways. While this study was limited to Brisbane’s near-home destinations, the results will be of interest to destination marketers and researchers interested in the challenge of positioning a destination in diverse markets.

‘Hot chicks’, ‘better parties’ or academic stuff : perceptions of a regional university campus using Repertory Grid Analysis and Importance-performance Analysis

In the increasingly competitive Australian tertiary education market, a consumer orientation is essential. This is particularly so for small regional campuses competing with larger universities in the state capitals. Campus management need to carefully monitor both the perceptions of prospective students within the catchment area, and the (dis)satisfaction levels of current students. This study reports the results of an exploratory investigation into the perceptions held of a regional campus, using two techniques that have arguably been underutilised in the education marketing literature. Repertory Grid Analysis, a technique developed almost fifty years ago, was used to identify attributes deemed salient to year 12 high school students at the time they were applying for university places. Importance-performance analysis (IPA), developed three decades ago, was then used to identify attributes that were determinant for a new cohort of first year undergraduate students. The paper concludes that group applications of Repertory Grid offer education market researchers a useful means for identifying attributes used by high school students to differentiate universities, and that IPA is a useful technique for guiding promotional decision making. In this case, the two techniques provided a quick, economical and effective snapshot of market perceptions, which can be used as a foundation for the development of an ongoing market research programme.

Cement-in-cement revision for selected Vancouver Type B1 femoral periprosthetic fractures : A biomechanical analysis

The aim of this study was to perform a biomechanical analysis of the cement-in-cement (c-in-c) technique for fixation of selected Vancouver Type B1 femoral periprosthetic fractures and to assess the degree of cement interposition at the fracture site. Six embalmed cadaveric femora were implanted with a cemented femoral stem. Vancouver Type B1 fractures were created by applying a combined axial and rotational load to failure. The femora were repaired using the c-in-c technique and reloaded to failure. The mean primary fracture torque was 117 Nm (SD 16.6, range 89–133). The mean revision fracture torque was 50 Nm (SD 16.6, range 29–74), which is above the torque previously observed for activities of daily living. Cement interposition at the fracture site was found to be minimal.

Collaborative research into the affordances of place for primary school children’s literacy learning

In the context of culturally diverse high poverty areas of Australia, we have conducted collaborative research with teachers and students in a primary school for more than a decade. Teachers have been exploring the affordances of place‐based pedagogies (Gruenewald & Smith, 2008) for the development of students’ spatial literacies and their understandings of the politics of places and built environments (Comber, Nixon, Ashmore, Loo & Cook, 2006; Comber, Thomson and Wells, 2001). This paper reports on a project in which the affordances of placedbased pedagogy are being explored through teacher inquiries and classroom‐based design experiments (Cobb, Confrey, di Sessa, Lehrer & Schauble, 2003). Located within a large‐scale urban renewal project in which houses are being demolished and families relocated, the original school has been replaced by a larger school that serves a population from a wider area. In this paper we draw on the study to consider the challenges of working with teachers and primary school students to study innovative ideas and practices in educational research. Specifically we consider issues raised by collaborative studies of the affordances of cross curricular projects focusing on social and environmental change to engage students in academic learning and expand their literate repertoires in a changing policy climate.

Context-aware device self-configuration using self-organizing maps

Modern mobile computing devices are versatile, but bring the burden of constant settings adjustment according to the current conditions of the environment. While until today, this task has to be accomplished by the human user, the variety of sensors usually deployed in such a handset provides enough data for autonomous self-configuration by a learning, adaptive system. However, this data is not fully available at certain points in time, or can contain false values. Handling potentially incomplete sensor data to detect context changes without a semantic layer represents a scientific challenge which we address with our approach. A novel machine learning technique is presented - the Missing-Values-SOM - which solves this problem by predicting setting adjustments based on context information. Our method is centered around a self-organizing map, extending it to provide a means of handling missing values. We demonstrate the performance of our approach on mobile context snapshots, as well as on classical machine learning datasets.

Detection of banana bunchy top virus in virus-infected plants using polymerase chain reaction

Polymerase chain reaction (PCR) was developed for the detection of Banana bunchy top virus (BBTV) at maximum after 210 min and at minimum after 90 min using Pc-1 and Pc-2, respectively. PCR detection of BBTV in crude sap indicated that the freezing of banana tissue in liquid nitrogen (LN2) before extraction was more effective than using sand as the extraction technique. BBTV was also detected using PCR assay in 69 healthy and diseased plants using Na-PO4 buffer containing 1 % SDS. PCR detection of BBTV in nucleic acid extracts using seven different extraction buffers to adapt the use of PCR in routine detection in the field was studied. Results proved that BBTV was detected with high sensitivity in nucleic acid extracts more than in infectious sap. The results also suggested the common aetiology for the BBTV by the PCR reactions of BBTV in nucleic acid extracts from Australia, Burundi, Egypt, France, Gabon, Philippines and Taiwan. Results also proved a positive relation between the Egyptian-BBTV isolate and abaca bunchy top isolate from the Philippines, but there no relation was found with the Cucumber mosaic cucumovirus (CMV) isolates from Egypt and Philippines and Banana bract mosaic virus (BBMV) were found.

Leadership for creating a thinking school at Buranda State School

This article explores the role of principal leadership in creating a thinking school. It contributes to the school leadership literature by exploring the intersection of two important areas of study in education - school leadership and education for thinking - which is a particularly apt area of study, because effective school leadership is crucial if students are to learn to be critical and creative thinkers, yet this connection has not be widely investigated. We describe how one principal, Hinton, turned around an underperforming school by using critical and creative philosophical thinking as the focus for students, staff and parents. Then, drawing on the school leadership literature, the article describes seven attributes of school leadership beginning with four articulated by Leithwood and colleagues (2006) (building vision and setting direction; redesigning the organisation; understanding and developing people; managing the teaching and learning program), and adding three others (influence; self-development; and responding to context). This framework is then used in a case study format in a collaboration between practitioner and researchers to first explore evidence from empirical studies and personal reflection about Hinton's leadership of Buranda State School, and second to illuminate how these general features of school leadership apply to creating a thinking school. Based on the case study and using the general characteristics of school leadership, a framework for leading a thinking school is described. Because the framework is based on a turnaround school, this framework has wide applicability: to schools that are doing well as an indication of how to implement a contemporary approach to curriculum and pedagogy; and to schools that are underperforming and want a rigorous, high expectation and contemporary way to improve student learning.

Mentoring pre-service teachers on school students’ differentiated learning

This Australian study explores the mentoring of pre-service teachers in selecting and implementing teaching strategies to meet students‟ learning needs. Two case studies involving 28 mentor teachers in a professional development program and a mentor-mentee partnership during a four week practicum provided data about mentoring teaching strategies for differentiated learning. Findings showed that contexts for learning about differentiation occurred at the pre action, in-action, and post-action stages. Central to each stage were pedagogical knowledge practices such as planning, preparation, classroom management, assessment, and problem solving (reflection-in-action to present solutions to problems) as key to in-action strategising and the mentoring processes. Mentoring pre-service teachers on how to devise teaching strategies for differentiated learning needs to be researched with a wider range of mentors and pre-service teachers, including those at different stages of development.

Ventilation distribution in rats : part 2 – a comparison of electrical impedance tomography and hyperpolarised helium magnetic resonance imaging

Background: Hyperpolarised helium MRI (He3 MRI) is a new technique that enables imaging of the air distribution within the lungs. This allows accurate determination of the ventilation distribution in vivo. The technique has the disadvantages of requiring an expensive helium isotope, complex apparatus and moving the patient to a compatible MRI scanner. Electrical impedance tomography (EIT) a non-invasive bedside technique that allows constant monitoring of lung impedance, which is dependent on changes in air space capacity in the lung. We have used He3MRI measurements of ventilation distribution as the gold standard for assessment of EIT. Methods: Seven rats were ventilated in supine, prone, left and right lateral position with 70% helium/30% oxygen for EIT measurements and pure helium for He3 MRI. The same ventilator and settings were used for both measurements. Image dimensions, geometric centre and global in homogeneity index were calculated. Results: EIT images were smaller and of lower resolution and contained less anatomical detail than those from He3 MRI. However, both methods could measure positional induced changes in lung ventilation, as assessed by the geometric centre. The global in homogeneity index were comparable between the techniques. Conclusion: EIT is a suitable technique for monitoring ventilation distribution and inhomgeneity as assessed by comparison with He3 MRI.