96,508 research outputs found
Using performance assessment in secondary school mathematics: an empirical study in a Singapore classroom
No full textThis article reports an exploratory study on using performance assessment in mathematics instruction in a high-performing secondary school in Singapore. An intact mathematics class participated in the study, and received chapter-based performance tasks as intervention during regular mathematics lessons for about one and a half school years. The performance tasks used included authentic and/or open-ended tasks. The students’ academic achievements and attitudes in mathematics were compared with a comparison class that did not receive the intervention. Both quantitative and qualitative data were collected, mainly through questionnaire surveys, performance task tests, conventional school exams, and interviews with students and teachers. The results suggest that the students receiving the intervention performed significantly better than their counterparts in solving conventional exam problems, and in general they also showed more positive changes in attitudes towards mathematics and mathematics learning. The students from the experimental class also expressed positive views about the benefits of using performance tasks in promoting their ability in higher order thinking, though no statistically significant difference was detected between the two classes of students in solving unconventional tasks before and after intervention. Overall, the results appear to support teachers’ using contextualised problems in real life situations and open-ended investigations in students’ learning of mathematic
A scholarly catalogue raisonné: George Wilson and the engraved fan leaf design 1795-1801
No full textABSTRACT
This research thesis offers a small but comprehensive scholarly catalogue raisonné of the surviving unmounted fan leaves designed and printed by the late eighteenth-century English fan leaf engraver, George Wilson (active before 1795-after 1801). Wilson’s extant output of nineteen fan leaf engravings published in London now exist in storage within the Prints and Drawing Department of the British Museum, after the receipt of two bequests from Lady Charlotte Schreiber (1812-1895) in the late nineteenth century. The individual fan leaf designs discussed in this catalogue raisonné include a number of reprinted fan leaves from the same engraving design.
There follows a chronological catalogue listing, and discussion of, all the different fan leaves designed by Wilson, collected by Lady Schreiber and subsequently bequeathed to the British Museum. The variety of subject matter depicted on these fan leaf designs underscore the differing types of themes Wilson engaged with in his engraved production. Analysis of the three main areas of Wilson’s fan leaf design work, female ‘advisory’ fan leaves, overtly satirical, and nationalistic fan leaves, reveal that Wilson’s fan leaf imagery engaged, to a great extent, with cultural concerns about the turbulences of late eighteenth-century life in London, as well as effectively modernising aesthetic precedents and contemporary graphic design. In particular, it becomes apparent that Wilson’s fan leaves effectively engage with late eighteenth-century feminine pre-occupations of choosing the right moral path to happiness, moderation in daily life, marriage and bearing children, in addition to illustrating the perceived multitude of follies translated from contemporary literary and pictorial sources. One of the predominant concerns in his catalogue of work is revealed to be the age old theme of the cycle of birth, reproduction and death, alongside a sustained pictorial focus upon feminine concerns and pre-occupations
Use of fan rig data for the understanding and prediction of fan broadband noise and noise changes due to a variable area nozzle
No full textThis thesis presents the results of the research component of this EngD, entitledUse of fan rig data for the understanding and prediction of fan broadband noise and noisechanges due to a variable area nozzleAs suggested by the title, fan rig noise measurements form an integral part of this thesis. Theanalysis of a database of rig noise measurements forms the first section of this thesis, in twoparts. The first part describes the analysis of a set of fan rig noise measurements, including thevariation of fan broadband and tone noise in forward and rearward arcs. The second partexamines a large database of fan rig noise measurements, and attempts to derive correlationsof fan broadband noise and fan performance parameters. Cluster Analysis, PrincipleComponent Analysis, and Regression Analysis are used to understand and describe theunderlying physics of broadband noise generation and the relationships between thesepredictors.The second section of this thesis uses a cascade broadband noise model to investigate rotorstatorbroadband noise. Predictions of the broadband noise from this noise model arecompared to rig measurements, showing good accuracy. The underlying physics of rotorstatorbroadband noise generation is investigated by performing two parametric studies usingthe broadband noise model. The first parametric study investigates the effect on broadbandnoise of simple flow and geometric parameters, namely number of vanes, vane chord, vanestagger angle, and rotor wake turbulence intensity, turbulent length scale, and flow Machnumber onto the cascade. These results are used to derive scaling power laws for theprediction of changes in broadband noise due to changes in these parameters. The secondparametric study expands upon this by investigating the effect on broadband noise of the fandesign parameters shaft speed, pressure ratio, and efficiency, at approach, cutback and cruiseconditions. The variation in broadband noise due to these design parameters is explained byconsidering the underlying flow and geometric parameters such as number of vanes and Machnumber, and the scaling power laws based on these simple parameters are used to predict thechange in broadband noise between different performance points.The final section of this thesis investigates the effect of varying exhaust nozzle area on totalengine noise. A new method is presented that allows the transfer of changes in fan rig noise toEugene P. Deane EngD Thesis September 2009 2engine noise predictions, to estimate the change in fan noise due to the pressure ratio changesbrought about by a variable area nozzle. Changes in engine noise are investigated forapproach, cutback, and sideline conditions, and the application of the new method assessed.As the research displayed in this thesis is closely linked to industry, the foundation of workpresented in several chapters is dependent on data or figures that are commercially sensitive.It has therefore been necessary to create a confidential appendix (Appendix X) to includethese commercially sensitive items. These additional results and figures in Appendix X aresupplementary in nature, and sufficient results are presented in the public thesis to illustratethe results of the various chapters. Where supplementary information and results are available,this is clearly indicated at the pertinent point in the published thesis, along with the section ofAppendix X where the information can be found
Are Bayesian Fan Charts Useful for Central Banks? Uncertainty, Forecasting, and Financial Stability Stress Tests
No full textThis paper shows how fan charts generated from Bayesian vector autoregression (BVAR) models can be useful for assessing 1) the forecasting accuracy of central banks’ prediction models and 2) the credibility of stress tests carried out to evaluate financial stability. Using unique data from the Czech National Bank (CNB), we compare our BVAR fan charts for inflation, GDP growth, interest rate and the exchange rate to those of the CNB, which are based on past forecasting errors. Our results suggest that in terms of the Kullback-Leibler Information Criterion, BVAR fan charts typically do not outperform those of the CNB, providing a useful cross-check of their accuracy. However, we show how BVAR fan charts can rigorously deal with the non-negativity constraint on the nominal interest rate and usefully complement the official fan charts. Finally, we put forward how BVAR fan charts can be useful for assessing financial stability and propose a simple method for evaluating whether the assumptions of banks’ stress tests about the macroeconomic outlook are sufficiently adverse.Bayesian vector autoregression, fan chart, inflation targeting, stress tests, uncertainty.
Fiscal fan charts - A tool for assessing member states’ (likely?) compliance with EU fiscal rules
No full textThis paper sets out a methodology for constructing fan charts for the government deficit and debt ratios over the medium-term. It relies on information contained in Stability/Convergence Programme Updates, a model of the relevant stochastic process (for example, the real GDP process) or processes, and a parameter estimate of the sensitivity of the primary budget balance to the output gap for the member state under consideration. A model of the dynamic deficit-debt relationship allows the impact of random output growth to work its way through the fiscal arithmetic in a consistent and traceable way to produce fan charts over a five-year forecast horizon. The initial set of fiscal fan charts included here for Ireland use the indicative public finance projections set out in the 2011 Update for Ireland. The range of possible fiscal outcomes in the charts assumes no fiscal policy response to any change in the budgetary position over the period such as could arise from changes in growth rates. This assumption of “no policy change” is a standard one in the construction of fan charts. Governments will, however, generally be in a position to adjust fiscal policy towards meeting a specific fiscal target, such as reaching a deficit position of less than 3 percent of GDP in the medium-term. A second set of fan charts is included which indicates how the probabilistic range of fiscal outcomes could be affected by a tightening of fiscal policy in 2013-2015.Programme Updates, fan charts, fiscal arithmetic, stochastic processes, prediction regions
Analysing International Sports Fan Motivations and Constraints: The Case of Japanese International Sports Fan Tourists and Rugby World Cup Fan Tourists
No full textThe scale of professional sports leagues and mega sports events has expanded recently. Many sports fans travel to foreign countries to watch international events featuring the world’s top athletes or players. The number of international sports fan tourists has increased, and understanding their behaviour is very important for stakeholders and those involved in marketing, such as sports organisations, travel companies, and government tourist organisations.
This study examines the motivations and constraints of Japanese international sports fan tourists and Japanese Rugby World Cup fan tourists. Sports fan tourists are tourists as well as sports fans. Many researchers have examined motivation either from a sports fan’s perspective or a tourist perspective. However, a motivation scale for international sports fan tourists (combining both sports fan and tourist motivations) has been not developed as there has been a lack of research into the behaviour of the international sports fan tourist.
The main research aim of this study is to analyse the motivation and constraint factors of both Japanese international sports fan tourists and Japanese Rugby World Cup tourists. The methodology aims to:
1.profile Japanese international sports fan tourists and Japanese Rugby World Cup tourists;
2.develop a motivational scale for actual sports fan tourists and a constraints scale for potential sports fan tourists (those who considered going but did not go);
3.analyse these factors according to demographics;
4.examine factors related to motivations and constraints on fans’ satisfaction, or their intention to attend future events.
A quantitative approach was employed. The main data collection methods were three email surveys:
1.Study 1 collected data about actual international sports fan tourists (N=338) and potential sports fan tourists (N=292).
2.Study 2 collected data about actual Rugby World Cup 1987-2007 tourists (N=101) and potential tourists (N=297).
3.Study 3 collected data about actual Rugby World Cup 2011 tourists (N=84) and potential tourists (N=115).
In previous studies, the sample was collected either from actual fans or potential fans separately; however, in this study, samples were collected not only from actual sports fan tourists but also from potential sports fan tourists from the same database.
The data analysis predominantly used explanatory factor analysis (EFA), confirmatory factor analysis (CFA), independent t-test, ANOVA, regression analysis, and structure equation modelling (SEM) including interaction effects analysis.
The results of this study were analysed using four steps:
1.Showing the demographic profiles and behavioural patterns of Japanese international sports fan tourists and Japanese Rugby World Cup fan tourists.
2.Developing motivation and constraints scales:
• an International Sports Fan Motivation Scale
• an International Sports Fan Tourist Motivation Scale
• an International Sports Fan Constraints Scale
• a Rugby World Cup Sports Fan Motivation Scale
• a Rugby World Cup Fan Tourist Motivation Scale
• a Rugby World Cup Fan Constraints Scale.
3.Comparing the mean scores of extracted factors by demographics such as gender, age, sports experiences etc.
4.Analysing the impact on satisfaction or future intention using interaction effect methods.
The results showed some interesting academic and practical implications. This study has thus made a significant and unique contribution to the knowledge of international sports fan behaviour by researching the combined sports fan motivation factors and tourist motivation factors of actual sports fans, and the constraints of potential sports fan tourists. The study has also provided an academic contribution to the sports and tourism fields, and has provided a practical contribution to the areas of sports fan behaviour, tourism, leisure constraints, and sports events management
Air and Water Flowrate Optimisation for a Fan Coil Unit in Heat Pump Systems
No full textThe degradation in efficiency of auxiliary components in heating/cooling systems when operating at part load is frequently reported. Through the use of variable speed components, the supplied capacity can be reduced to match the required load and hence reduce unnecessary energy consumption. However, for fan coil units, difficulties can arise when optimizing fan and pump speeds at part load. Practically locating optimal water and air flow rates from readily available information and for varying supplied capacities is necessary, in order to reduce the fan coil power consumption. This research attempts to identify whether optimal fan and pump speeds exist for a fan coil unit and how they can be implemented, in a practical manner, in a system control applications. Using an empirical fan coil and pump model, the total power consumption (fan and pump) for different combinations of fan and pump speeds over a range of capacities was calculated. It was observed that, for a given capacity, an optimal combination of fan and pump speeds exists and there was a significant change in power consumption for different combinations of fan and pump speeds supplying the same capacity. A control strategy is described that utilizes a simple fan coil capacity estimation model, coupled with air and water flow rates, along with nominal design data. The pump speed is optimized using PID control to maintain the space temperature at the chosen set-point, which matches the supplied capacity to the required capacity. At set-time intervals, the capacity estimation model is utilized to optimize the water and air flow rates for the required capacity. The control strategy is evaluated, using a full building simulation model for a daily load profile and is compared to two baseline conditions: for no control of the fancoils/pump combination and for PID circulation control of the pump only. The optimal fan and pump speed control resulted in a 43% and 24% decrease in power consumption with compared to the no control baseline and the PID controlled circulation pump strategy, respectively
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Enhanced colour encoding of materials discrimination information for multiple view dual-energy x-ray imaging
No full textThis thesis reports an investigation into dual-energy X-ray discrimination techniques. These techniques are designed to provide colour-coded materials discrimination information in a sequence of perspective images exhibiting sequential parallax. The methods developed are combined with a novel 3D imaging technique employing depth from motion or kinetic depth effect (KDE). This technique when applied to X-ray images is termed KDEX imaging and was developed previously by the university team for luggage screening applications at security checkpoints. A primary motivation for this research is that the dual-energy X-ray techniques, which are routinely incorporated into ‘standard’ 2D luggage scanners, provide relatively crude materials discrimination information. In this work it was critical that robust materials discrimination and colour encoding process was implemented as the sequential parallax exhibited by the KDEX imagery may introduce colour changes, due to the different X-ray beam paths associated with each perspective image. Any introduction of ‘colour noise’ into the resultant image sequences could affect the perception of depth and hinder the ongoing assessment of the potential utility of the dual-energy KDEX technique. Two dual-energy discrimination methods have been developed, termed K-II and W-E respectively. Employing the total amount of attenuation measured at each energy level and the weight fraction of layered structures, a combination of the K-II and the W-E techniques enables the computation and extraction of a target objects’ effective atomic number (Zeff) and its surface density (ρS) in the presence of masking layers
Different types of gravity-driven flow deposits and associated bedforms in the Upper Bengal Fan, offshore Myanmar
No full textThis study uses 3D reflection seismic data to investigate how sediment gravity flows contribute to the evolution of the lower continental slope of the Myanmar margin that is part of the Bengal Fan, the largest deep-water fan system in the world. Seafloor and subseafloor data show large sediment wave fields that developed on both flanks of an extensive submarine canyon. The sediment waves exhibit asymmetric stoss and lee sides, wave lengths and heights of 850–3000 m and 25–70 m, respectively, and an upslope direction of migration. Seismic data reveals the presence of multiple fields of vertically stacked sediment waves, interbedded with units characterised by a chaotic seismic facies that accumulate mainly in the troughs of the sediment waves and can be tracked laterally to the adjacent canyons. According to their seismic facies, geometry, and internal architecture these chaotic units are interpreted as debrites. Seismic attributes extracted from different horizons indicate that the sediment waves are dominated by fine-grained sediment, while the debrites are probably associated with coarser-grained deposits. The debrites fill the troughs of the sediment waves, as well as the downstream portions of canyon thalweg, thus flattening the paleo-seafloor. The sediment waves are interpreted as cyclic steps formed by low-density turbidity currents flowing across the slope down to the basin floor, where the change in gradient favours the formation of hydraulic jumps and the transition from supercritical to subcritical flow conditions. A conceptual model for the sediment wave evolution was proposed for the study area, in the transitional environment on the lower slope, with low-density gravity flow deposits and high-density debris flow deposits alternatively accumulating on the major gravity flow conduits
Traces and shards of self-injury: Strange accounting with “Author X”
No full textIn this strange account autoethnography, three or four authors explore their lived experiences with self-injury. Strange accounting is both a post-modern style of text, and a method for keeping identities concealed when risks and secrets are in play. Author X, a post-modern place-keeper for an anonymous author who may or may not have contributed to this manuscript, introduces a new dimension and layer of concealment. With Author X in-play and under erasure, the reader will never be sure if there were three or four authors on this manuscript. Through strange accounting, a post-structuralist/postmodernist frame will be applied to understanding the self-injury experience. We frame self-injury as a social practice and, for some, an everyday norm, while remaining acutely aware of the stigma surrounding the topic of self-injury. Each of us, coupled with Author X, provide the others cover to trace stories of self-injury through the literature, our flesh, and our lives
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