Engineering

Publication Search Results

Now showing 1 - 10 of 30
  • (2002) Magin, Douglas; Helmore, Phillip
    Conference Paper
    Despite numerous studies on the reliability of peer marking of oral presentation skills, no empirical studies to date have addressed the validity issue of whether students use a different 'perspective' from teachers in making an overall assessment. This paper analyses peer and teacher assessment data from thesis presentations made by students enrolled in a fourth year subject 'Communications for Professional Engineers'. The study uses a novel application of the 'index of association' statistic to determine the extent to which the variance of marks by teachers and by peers for the overall quality of the presentations can be attributed to factors other than errors associated with unreliable measures. Results indicate that students had applied criteria which were quite different from those used by teachers. The discussion describes methodologies which can be employed to determine which skill criteria are most influential in the determination of a global mark for oral presentations, and outlines plans to identify the ways in which students and staff differ in the criteria they apply.

  • (2008) Wakefield, Claire; Meiser, Bettina; Gaff, C; Barratt, Anthony; Patel, Minoo; Suthers, G; Lobb, Elizabeth; Ramsay, J; Mann, G
    Journal Article
    Purpose: Despite the established importance of the role of family history in prostate cancer, relatively little research encompasses the psychosocial issues relevant to unaffected men with a family history of prostate cancer. To determine the completeness and quality of available literature on the issues faced by men with a high risk of prostate cancer, we conducted a multidisciplinary review of the literature to provide some guidance on the information that clinicians might provide to men who are concerned about family history. Materials and Methods: A structured literature search was conducted by a multidisciplinary team of clinicians and researchers who reviewed the medical and psychosocial literature, and identified 21 relevant studies. Results: Research suggests that many high risk patients are concerned about the risk of prostate cancer, and some may significantly overestimate that risk. Several studies have shown high screening rates among high risk patients and high levels of interest in genetic testing for prostate cancer risk should it become available, yet many men also report a desire for more information about their personal risk and risk management options. Conclusions: Given the lack of clear data on the efficacy of prostate cancer screening among high risk patients, clinicians could consider providing men who are concerned about family history with information on their personal risk, help them to clarify the potential benefits, limitations and harms of prostate cancer screening in their situation, and then support their choice regarding the management of prostate cancer risk.

  • (2001) Magin, Douglas; Helmore, Phillip
    Conference Paper
    Recent reviews on assessment in higher education have emphasised the importance of written formative assessment as part of the process of assessing oral presentation skills, and have identified the need for case studies to investigate the content and character of feedback which students receive. The paper analyses the written feedback provided by teachers who acted as assessors for conference presentations made by engineering students enrolled in a fourth year subject at The University of New South Wales. The study employs content analysis to describe the extent, content, and character of these comments, and to identify which performance skills staff focus on in providing such feedback.

  • (2003) Magin, Douglas; Helmore, Phillip; Barber, Tracie J
    Conference Paper
    A number of studies have questioned the criterion validity of peer assessed oral presentations. Claims have been made that students are likely to employ a different perspective from teachers when assessing overall presentation quality, even when both are guided by a common checklist of relevant skill components.To date, no empirical investigations have been undertaken to determine how students differ from staff in the criteria they apply. this paper analyses peer and teacher assessment data from thesis presentations made by engineering students in a fourth year communications subject. The data consists of peer and teacher ratings on eight skill components listed on a checklist (used for feedback only), together with a global mark for the presentation (the summative assessment).The scores on the eight items were then subject to multiple regression analysis using the global mark as the criterion. Substantial differences were found between the two multiple regression equations. Discussion focuses on how these differences affect the validity of peer assessments, and the level of agreement between teacher and student assessment.

  • (2007) Churches, Alex; Green, Cliff; Field, Bruce; Wightley, Allan; Green, Lance; van de Loo, Paul; Burvill, Colin; Smith, Warren; Snook, Chris
    Conference Paper

  • (2013) Zhang, Haoyang; Hawkes, Evatt; Chen, Jacqueline; Kook, Sanghoon
    Journal Article
    The autoignition of dimethyl ether (DME) with temperature inhomogeneities is investigated by one-dimensional numerical simulations with detailed chemistry at high pressure and a constant volume. The primary purpose of the study is to provide an understanding of the autoignition of DME in a simplified configuration that is relevant to homogeneous charge compression ignition (HCCI) engines. The ignition structure and the negative temperature coefficient (NTC) behaviour are characterised in a homogeneous domain and one-dimensional domains with thermal stratification, at different initial mean temperatures and length scales. The thermal stratification is shown to strongly affect the spatial structure and temporal progress of ignition. The importance of diffusion and conduction on the ignition progress is assessed. It is shown that the effects of molecular diffusion decay relative to those of chemical reaction as the length-scale increases. This is to be expected, however the present study shows that these characteristics also depend on the mean temperature due to NTC behaviour. For the range of conditions studied here, which encompass a range of stratification length scales expected in HCCI engines, the effects of molecular transport are found to be small compared with chemical reaction effects for mean temperatures within the NTC regime. This is in contrast to previous work with fuels with single-stage ignition behaviour where practically realisable temperature gradients can lead to molecular transport effects becoming important. In addition, thermal stratification is demonstrated to result in significant reductions of the pressure-rise rate (PRR), even for the present fuel with two-stage ignition and NTC behaviour. The reduction of PRR is however strongly dependent on the mean initial temperature. The stratification length-scale is also shown to have an important influence on the pressure oscillations, with large-amplitude oscillations possible for larger length scales typical of integral scales in HCCI engines.

  • (2008) Mak, Lin Chi; Whitty, Mark; Furukawa, Tomonari
    Journal Article
    Purpose – The purpose of this paper is to present a localisation system for an indoor rotary-wing micro aerial vehicle (MAV) that uses three onboard LEDs and base station mounted active vision unit. Design/methodology/approach – A pair of blade mounted cyan LEDs and a tail mounted red LED are used as on-board landmarks. A base station tracks the landmarks and estimates the pose of the MAV in real time by analysing images taken using an active vision unit. In each image, the ellipse formed by the cyan LEDs is used for 5 degree of freedom (DoF) pose estimation with yaw estimation from the red LED providing the 6th DoF. Findings – About 1-3.5 per cent localisation error of the MAV at various ranges, rolls and angular speeds less than 45°/s relative to the base station at known location indicates that the MAV can be accurately localised at 9-12?Hz in an indoor environment. Research limitations/implications – Line-of-sight between the base station and MAV is necessary while limited accuracy is evident in yaw estimation at long distances. Additional yaw sensors and dynamic zoom are among future work. Practical implications – Provided an unmanned ground vehicle (UGV) as the base station equipped with its own localisation sensor, the developed system encourages the use of autonomous indoor rotary-wing MAVs in various robotics applications, such as urban search and rescue. Originality/value – The most significant contribution of this paper is the innovative LED configuration allowing full 6 DoF pose estimation using three LEDs, one camera and no fixed infrastructure. The active vision unit enables a wide range of observable flight as the ellipse generated by the cyan LEDs is recognisable from almost any direction.

  • (2008) Mak, Lin Chi; Furukawa, Tomonari
    Journal Article
    This paper presents a non-line-of-sight (NLOS) localization technique and its system for a quiet and known environment that uses first-arrival low-frequency acoustic signals. The proposed technique first measures the time-of-arrivals (ToAs) of the first-arrival low-frequency sounds. The technique then estimates the location of a target by minimizing the differences between the measured ToAs and the corresponding ToAs estimated from the known map. The strength of the proposed technique is that the positioning accuracy is not corrupted by any small or known obstacle. The performance of the technique was investigated by its comparison to other techniques in both simulations and an experiment. The numerical results show successful localization of a target in various situations, demonstrating the efficacy of the technique and system as a feasible solution for NLOS mitigation.

  • (2007) Alshroof, Osama; Reizes, John; Timchenko, Victoria; Leonardi, Eddie
    Conference Paper
    ABSTRACT A numerical investigation has been performed as to the feasibility of using spherical indentations in a flat plate for enhancing heat transfer in the laminar regime. An attempt to validate the calculation procedure resulted in a significant difference with previously published results, in which the inlet boundary condition was stated to be the Polhausen distribution. An investigation of the disparity lead to a study of the effects of various boundary conditions on the development of laminar boundary layers on an infinitesimally thin flat plate. In two-dimensions, regions appear in which velocities are greater than the free stream velocity (overshoot), unless the Blasius distribution is used to predict the inlet velocity in both directions. Surprisingly, although regions of overshoot occur when areas upstream and downstream of the plate are included in calculating the flow near the plate, the velocity distribution within the boundary layer is well represented by the Blasius profile for most of the plate. Outside the boundary layer the velocity distribution depends on the position and the length of the plate. Calculations in three dimensions using inlet boundary conditions developed from the two-dimensional study indicate that a single dimple does not enhance heat transfer.

  • (2008) Vogt, Jonathan William; Barber, Tracie J; Leonardi, Eddie
    Journal Article
    A Computational Fluid Dynamics investigation was conducted to ascertain and highlight the different ways in which ground effect phenomena are present around both an upright (lift generating) and inverted (downforce generating) cambered aerofoil when in close proximity to the ground. The trends in force and flow field behaviour were observed at various ground clearances, while the angle of attack was held constant at 6 degrees. The different mechanisms by which ground effect influences the two different configurations were highlighted through observation of the pressure coefficient plots, contour maps of velocity and turbulence intensity and their effect on the normal and drag forces. The primary contributing factor to the increase in normal force for the lifting aerofoil, as the ground was approached, was a constriction and rise in pressure of the flow. For the downforce aerofoil, a significantly sped up flow increased suction and enhanced downforce. Also discussed is the observation of a reduction in lift for the upright aerofoil as its ground clearance is reduced through high and medium clearances.