Axial length charges during accommodation in myopes and emmetropes

Purpose: To investigate the influence of accommodation upon axial length (and a comprehensive range of ocular biometric parameters), in populations of young adult myopic and emmetropic subjects. Methods: Forty young adult subjects had ocular biometry measured utilizing a non-contact optical biometer (Lenstar LS 900) based upon the principle of optical low coherence reflectometry, under three different accommodation demands (0 D, 3 D and 6 D). Subjects were classified as emmetropes (n=19) or myopes (n=21) based upon their spherical equivalent refraction (mean emmetropic refraction -0.05 ± 0.27DS and mean myopic refraction -1.82 ± 0.84 DS). Results: Axial length changed significantly with accommodation, with a mean increase of 11.9 ± 12.3 µm and 24.1 ± 22.7 µm for the 3 D and 6 D accommodation stimuli respectively. A significant axial elongation associated with accommodation was still evident even following correction of the axial length data for potential error due to lens thickness change. The mean ‘corrected’ increase in axial length was 5.2 ± 11.2 µm, and 7.4 ± 18.9 µm for the 3 D and 6 D stimuli respectively. There was no significant difference between the myopic and emmetropic populations in terms of the magnitude of change in axial length with accommodation, regardless of whether the data were corrected or not. A number of other ocular biometric parameters, such as anterior chamber depth, lens thickness and vitreous chamber depth also exhibited significant change with accommodation. The myopic and emmetropic populations also exhibited no significant difference in the magnitude of change in these parameters with accommodation. Conclusions: The eye undergoes a significant axial elongation associated with a brief period of accommodation, and the magnitude of this change in eye length increases for larger accommodation demands, however there is no significant difference in the magnitude of eye elongation in myopic and emmetropic subjects.

The effect of presbyiopic vision corrections on nighttime driving performance

Purpose. To investigate the effect of various presbyopic vision corrections on nighttime driving performance on a closed-road driving circuit. Methods. Participants were 11 presbyopes (mean age, 57.3 ± 5.8 years), with a mean best sphere distance refractive error of R+0.23±1.53 DS and L+0.20±1.50 DS, whose only experience of wearing presbyopic vision correction was reading spectacles. The study involved a repeated-measures design by which a participant's nighttime driving performance was assessed on a closed-road circuit while wearing each of four power-matched vision corrections. These included single-vision distance lenses (SV), progressive-addition spectacle lenses (PAL), monovision contact lenses (MV), and multifocal contact lenses (MTF CL) worn in a randomized order. Measures included low-contrast road hazard detection and avoidance, road sign and near target recognition, lane-keeping, driving time, and legibility distance for street signs. Eye movement data (fixation duration and number of fixations) were also recorded. Results. Street sign legibility distances were shorter when wearing MV and MTF CL than SV and PAL (P < 0.001), and participants drove more slowly with MTF CL than with PALs (P = 0.048). Wearing SV resulted in more errors (P < 0.001) and in more (P = 0.002) and longer (P < 0.001) fixations when responding to near targets. Fixation duration was also longer when viewing distant signs with MTF CL than with PAL (P = 0.031). Conclusions. Presbyopic vision corrections worn by naive, unadapted wearers affected nighttime driving. Overall, spectacle corrections (PAL and SV) performed well for distance driving tasks, but SV negatively affected viewing near dashboard targets. MTF CL resulted in the shortest legibility distance for street signs and longer fixation times.

Network

Network has emerged from a contempory worldwide phenomenon, culturally manifested as a consequence of globalization and the knowledge economy. It is in this context that the internet revolution has prompted a radical re-ordering of social and institutional relations and the associated structures, processes and places which support them. Within the duality of virtual space and the augmentation of traditional notions of physical place, the organizational structures pose new challenges for the design professions. Technological developments increasingly permit communication anytime and anywhere, and provide the opportunity for both synchronous and asynchronous collaboration. The resultant ecology formed through the network enterprise has resulted in an often convolted and complex world wherein designers are forced to consider the relevance and meaning of this new context. The role of technology and that of space are thus interwined in the relation between the network and the individual workplace. This paper explores a way to inform the interior desgn process for contemporary workplace environments. It reports on both theoretical and practical outcomes through an Australia-wide case study of three collaborating, yet independent business entities. It further suggests the link between workplace design and successful business innovation being realized between partnering organizations in Great Britain. Evidence presented indicates that, for architects and interior designers, the scope of the problem has widened, the depth of knowledge required to provide solutions has increased, and the rules of engagement are required to change. The ontological and epistemological positions adopted in the study enabled the spatial dimensions to be examined from both within and beyond the confines of a traditional design only viewpoint. Importantly it highlights the significance of a trans-disiplinary collaboration in dealing with the multiple layers and complexity of the contemporary social and business world, from both a research and practice perspective.

Patterns

In recent years there has been widespread interest in patterns, perhaps provoked by a realisation that they constitute a fundamental brain activity and underpin many artificial intelligence systems. Theorised concepts of spatial patterns including scale, proportion, and symmetry, as well as social and psychological understandings are being revived through digital/parametric means of visualisation and production. The effect of pattern as an ornamental device has also changed from applied styling to mediated dynamic effect. The interior has also seen patterned motifs applied to wall coverings, linen, furniture and artefacts with the effect of enhancing aesthetic appreciation, or in some cases causing psychological and/or perceptual distress (Rodemann 1999). ----- ----- While much of this work concerns a repeating array of surface treatment, Philip Ball’s The Self- Made Tapestry: Pattern Formation in Nature (1999) suggests a number of ways that patterns are present at the macro and micro level, both in their formation and disposition. Unlike the conventional notion of a pattern being the regular repetition of a motif (geometrical or pictorial) he suggests that in nature they are not necessarily restricted to a repeating array of identical units, but also include those that are similar rather than identical (Ball 1999, 9). From his observations Ball argues that they need not necessarily all be the same size, but do share similar features that we recognise as typical. Examples include self-organized patterns on a grand scale such as sand dunes, or fractal networks caused by rivers on hills and mountains, through to patterns of flow observed in both scientific experiments and the drawings of Leonardo da Vinci.

Developing an IS-Impact decision tool : a literature based design science roadmap

This paper derives from research-in-progress intending both Design Research (DR) and Design Science (DS) outputs; the former a management decision tool based in IS-Impact (Gable et al. 2008) kernel theory; the latter being methodological learnings deriving from synthesis of the literature and reflection on the DR ‘case study’ experience. The paper introduces a generic, detailed and pragmatic DS ‘Research Roadmap’ or methodology, deriving at this stage primarily from synthesis and harmonization of relevant concepts identified through systematic archival analysis of related literature. The scope of the Roadmap too has been influenced by the parallel study aim to undertake DR applying and further evolving the Roadmap. The Roadmap is presented in attention to the dearth of detailed guidance available to novice Researchers in Design Science Research (DSR), and though preliminary, is expected to evolve and gradually be substantiated through experience of its application. A key distinction of the Roadmap from other DSR methods is its breadth of coverage of published DSR concepts and activities; its detail and scope. It represents a useful synthesis and integration of otherwise highly disparate DSR-related concepts.

A design science research roadmap

This paper proposes and synthesizes from previous design science(DS) methodological literature a structured and detailed DS Roadmap for the conduct of DS research. The Roadmap is a general guide for researchers to carry out DS research by suggesting reasonably detailed activities.Though highly tentative, it is believed the Roadmap usefully inter-relates many otherwise seemingly disparate, overlapping or conflicting concepts. It is hoped the DS Roadmap will aid in the planning, execution and communication of DS research,while also attracting constructive criticism, improvements and extensions. A key distinction of the Roadmap from other DS research methods is its breadth of coverage of DS research aspects and activities; its detail and scope. We demonstrate and evaluate the Roadmap by presenting two case studies in terms of the DS Roadmap.

Recognising Torres Strait Islander women’s knowledges in their children’s mathematics education

This paper discusses women’s involvement in their children’s mathematics education. It does, where possible, focus Torres Strait Islander women who share the aspirations of Aborginal communities around Australia. That is, they are keen for their children to receive an education that provides them with opportunities for their present and future lives. They are also keen to have their cultures’ child learning practices recognised and respected within mainstream education. This recognition has some way to go with the language of instruction in schools written to English conventions, decontextualised and disconnected to the students’ culture, Community and home language.

Performance control of distributed generation using digital estimation of signal parameters

The Queensland University of Technology (QUT) allows the presentation of a thesis for the Degree of Doctor of Philosophy in the format of published or submitted papers, where such papers have been published, accepted or submitted during the period of candidature. This thesis is composed of seven published/submitted papers, of which one has been published, three accepted for publication and the other three are under review. This project is financially supported by an Australian Research Council (ARC) Discovery Grant with the aim of proposing strategies for the performance control of Distributed Generation (DG) system with digital estimation of power system signal parameters. Distributed Generation (DG) has been recently introduced as a new concept for the generation of power and the enhancement of conventionally produced electricity. Global warming issue calls for renewable energy resources in electricity production. Distributed generation based on solar energy (photovoltaic and solar thermal), wind, biomass, mini-hydro along with use of fuel cell and micro turbine will gain substantial momentum in the near future. Technically, DG can be a viable solution for the issue of the integration of renewable or non-conventional energy resources. Basically, DG sources can be connected to local power system through power electronic devices, i.e. inverters or ac-ac converters. The interconnection of DG systems to power system as a compensator or a power source with high quality performance is the main aim of this study. Source and load unbalance, load non-linearity, interharmonic distortion, supply voltage distortion, distortion at the point of common coupling in weak source cases, source current power factor, and synchronism of generated currents or voltages are the issues of concern. The interconnection of DG sources shall be carried out by using power electronics switching devices that inject high frequency components rather than the desired current. Also, noise and harmonic distortions can impact the performance of the control strategies. To be able to mitigate the negative effect of high frequency and harmonic as well as noise distortion to achieve satisfactory performance of DG systems, new methods of signal parameter estimation have been proposed in this thesis. These methods are based on processing the digital samples of power system signals. Thus, proposing advanced techniques for the digital estimation of signal parameters and methods for the generation of DG reference currents using the estimates provided is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1. One of the main parameters of a power system signal is its frequency. Phasor Measurement (PM) technique is one of the renowned and advanced techniques used for the estimation of power system frequency. Chapter 2 focuses on an in-depth analysis conducted on the PM technique to reveal its strengths and drawbacks. The analysis will be followed by a new technique proposed to enhance the speed of the PM technique while the input signal is free of even-order harmonics. The other techniques proposed in this thesis as the novel ones will be compared with the PM technique comprehensively studied in Chapter 2. An algorithm based on the concept of Kalman filtering is proposed in Chapter 3. The algorithm is intended to estimate signal parameters like amplitude, frequency and phase angle in the online mode. The Kalman filter is modified to operate on the output signal of a Finite Impulse Response (FIR) filter designed by a plain summation. The frequency estimation unit is independent from the Kalman filter and uses the samples refined by the FIR filter. The frequency estimated is given to the Kalman filter to be used in building the transition matrices. The initial settings for the modified Kalman filter are obtained through a trial and error exercise. Another algorithm again based on the concept of Kalman filtering is proposed in Chapter 4 for the estimation of signal parameters. The Kalman filter is also modified to operate on the output signal of the same FIR filter explained above. Nevertheless, the frequency estimation unit, unlike the one proposed in Chapter 3, is not segregated and it interacts with the Kalman filter. The frequency estimated is given to the Kalman filter and other parameters such as the amplitudes and phase angles estimated by the Kalman filter is taken to the frequency estimation unit. Chapter 5 proposes another algorithm based on the concept of Kalman filtering. This time, the state parameters are obtained through matrix arrangements where the noise level is reduced on the sample vector. The purified state vector is used to obtain a new measurement vector for a basic Kalman filter applied. The Kalman filter used has similar structure to a basic Kalman filter except the initial settings are computed through an extensive math-work with regards to the matrix arrangement utilized. Chapter 6 proposes another algorithm based on the concept of Kalman filtering similar to that of Chapter 3. However, this time the initial settings required for the better performance of the modified Kalman filter are calculated instead of being guessed by trial and error exercises. The simulations results for the parameters of signal estimated are enhanced due to the correct settings applied. Moreover, an enhanced Least Error Square (LES) technique is proposed to take on the estimation when a critical transient is detected in the input signal. In fact, some large, sudden changes in the parameters of the signal at these critical transients are not very well tracked by Kalman filtering. However, the proposed LES technique is found to be much faster in tracking these changes. Therefore, an appropriate combination of the LES and modified Kalman filtering is proposed in Chapter 6. Also, this time the ability of the proposed algorithm is verified on the real data obtained from a prototype test object. Chapter 7 proposes the other algorithm based on the concept of Kalman filtering similar to those of Chapter 3 and 6. However, this time an optimal digital filter is designed instead of the simple summation FIR filter. New initial settings for the modified Kalman filter are calculated based on the coefficients of the digital filter applied. Also, the ability of the proposed algorithm is verified on the real data obtained from a prototype test object. Chapter 8 uses the estimation algorithm proposed in Chapter 7 for the interconnection scheme of a DG to power network. Robust estimates of the signal amplitudes and phase angles obtained by the estimation approach are used in the reference generation of the compensation scheme. Several simulation tests provided in this chapter show that the proposed scheme can very well handle the source and load unbalance, load non-linearity, interharmonic distortion, supply voltage distortion, and synchronism of generated currents or voltages. The purposed compensation scheme also prevents distortion in voltage at the point of common coupling in weak source cases, balances the source currents, and makes the supply side power factor a desired value.

Complex learning through cognitively demanding tasks

The world’s increasing complexity, competitiveness, interconnectivity, and dependence on technology generate new challenges for nations and individuals that cannot be met by “continuing education as usual” (The National Academies, 2009). With the proliferation of complex systems have come new technologies for communication, collaboration, and conceptualization. These technologies have led to significant changes in the forms of mathematical thinking that are required beyond the classroom. This paper argues for the need to incorporate future-oriented understandings and competencies within the mathematics curriculum, through intellectually stimulating activities that draw upon multidisciplinary content and contexts. The paper also argues for greater recognition of children’s learning potential, as increasingly complex learners capable of dealing with cognitively demanding tasks.

Impact of a data warehouse model for improved decision-making process in healthcare

The health system is one sector dealing with a deluge of complex data. Many healthcare organisations struggle to utilise these volumes of health data effectively and efficiently. Also, there are many healthcare organisations, which still have stand-alone systems, not integrated for management of information and decision-making. This shows, there is a need for an effective system to capture, collate and distribute this health data. Therefore, implementing the data warehouse concept in healthcare is potentially one of the solutions to integrate health data. Data warehousing has been used to support business intelligence and decision-making in many other sectors such as the engineering, defence and retail sectors. The research problem that is going to be addressed is, "how can data warehousing assist the decision-making process in healthcare". To address this problem the researcher has narrowed an investigation focusing on a cardiac surgery unit. This research used the cardiac surgery unit at the Prince Charles Hospital (TPCH) as the case study. The cardiac surgery unit at TPCH uses a stand-alone database of patient clinical data, which supports clinical audit, service management and research functions. However, much of the time, the interaction between the cardiac surgery unit information system with other units is minimal. There is a limited and basic two-way interaction with other clinical and administrative databases at TPCH which support decision-making processes. The aims of this research are to investigate what decision-making issues are faced by the healthcare professionals with the current information systems and how decision-making might be improved within this healthcare setting by implementing an aligned data warehouse model or models. As a part of the research the researcher will propose and develop a suitable data warehouse prototype based on the cardiac surgery unit needs and integrating the Intensive Care Unit database, Clinical Costing unit database (Transition II) and Quality and Safety unit database [electronic discharge summary (e-DS)]. The goal is to improve the current decision-making processes. The main objectives of this research are to improve access to integrated clinical and financial data, providing potentially better information for decision-making for both improved from the questionnaire and by referring to the literature, the results indicate a centralised data warehouse model for the cardiac surgery unit at this stage. A centralised data warehouse model addresses current needs and can also be upgraded to an enterprise wide warehouse model or federated data warehouse model as discussed in the many consulted publications. The data warehouse prototype was able to be developed using SAS enterprise data integration studio 4.2 and the data was analysed using SAS enterprise edition 4.3. In the final stage, the data warehouse prototype was evaluated by collecting feedback from the end users. This was achieved by using output created from the data warehouse prototype as examples of the data desired and possible in a data warehouse environment. According to the feedback collected from the end users, implementation of a data warehouse was seen to be a useful tool to inform management options, provide a more complete representation of factors related to a decision scenario and potentially reduce information product development time. However, there are many constraints exist in this research. For example the technical issues such as data incompatibilities, integration of the cardiac surgery database and e-DS database servers and also, Queensland Health information restrictions (Queensland Health information related policies, patient data confidentiality and ethics requirements), limited availability of support from IT technical staff and time restrictions. These factors have influenced the process for the warehouse model development, necessitating an incremental approach. This highlights the presence of many practical barriers to data warehousing and integration at the clinical service level. Limitations included the use of a small convenience sample of survey respondents, and a single site case report study design. As mentioned previously, the proposed data warehouse is a prototype and was developed using only four database repositories. Despite this constraint, the research demonstrates that by implementing a data warehouse at the service level, decision-making is supported and data quality issues related to access and availability can be reduced, providing many benefits. Output reports produced from the data warehouse prototype demonstrated usefulness for the improvement of decision-making in the management of clinical services, and quality and safety monitoring for better clinical care. However, in the future, the centralised model selected can be upgraded to an enterprise wide architecture by integrating with additional hospital units’ databases.

Analysis for the use of cumulative plots for travel time estimation on signalized network

This paper provides fundamental understanding for the use of cumulative plots for travel time estimation on signalized urban networks. Analytical modeling is performed to generate cumulative plots based on the availability of data: a) Case-D, for detector data only; b) Case-DS, for detector data and signal timings; and c) Case-DSS, for detector data, signal timings and saturation flow rate. The empirical study and sensitivity analysis based on simulation experiments have observed the consistency in performance for Case-DS and Case-DSS, whereas, for Case-D the performance is inconsistent. Case-D is sensitive to detection interval and signal timings within the interval. When detection interval is integral multiple of signal cycle then it has low accuracy and low reliability. Whereas, for detection interval around 1.5 times signal cycle both accuracy and reliability are high.

The undesirable acetylation of cellulose by the acetate ion of 1-ethyl-3-methylimidazolium acetate

The ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim]OAc) is considered to be an inert solvent of cellulose and lignocellulosic biomass. Acetylation (1.7 % mol, or DS 0.017) of cellulose after dissolution in [C2mim]OAc (150 °C for 20 min), is demonstrated by compositional analysis, FTIR analysis and 13C NMR spectroscopy (in [C2min]OAc with 13C enriched acetate). This acetylation, in the absence of added acylating agents, has not been reported before and may limit [C2mim]OAc utility in industrial scale biomass processing, even at this low extent. For example, cellulose acetylation may contribute to IL loss in processes where the IL is recovered and reused and inhibit enzyme saccharification of cellulose in lignocellulosic biofuel production processes based on saccharification and fermentation.

Mining a data reasoning model for personalized text classification

It is a big challenge to acquire correct user profiles for personalized text classification since users may be unsure in providing their interests. Traditional approaches to user profiling adopt machine learning (ML) to automatically discover classification knowledge from explicit user feedback in describing personal interests. However, the accuracy of ML-based methods cannot be significantly improved in many cases due to the term independence assumption and uncertainties associated with them. This paper presents a novel relevance feedback approach for personalized text classification. It basically applies data mining to discover knowledge from relevant and non-relevant text and constraints specific knowledge by reasoning rules to eliminate some conflicting information. We also developed a Dempster-Shafer (DS) approach as the means to utilise the specific knowledge to build high-quality data models for classification. The experimental results conducted on Reuters Corpus Volume 1 and TREC topics support that the proposed technique achieves encouraging performance in comparing with the state-of-the-art relevance feedback models.

Are motivational deficits part of the behavioural phenotype of Down syndrome?

Motivational deficits are generally accepted to be part of the behavioural phenotype associated with Down syndrome (DS). A motivational profile comprising low or inconsistent levels of task persistence, avoidance of challenging activities and over-dependence on adult direction has been described. However, comparisons are usually made between children with DS and those who are developing typically, without the inclusion of samples with intellectual disability (ID) from aetiologies other than DS. Such comparisons are needed to determine the extent to which motivational deficits are specific to DS, as opposed to being a feature of ID generally. Methods: The current study collected data about the personality-motivation profiles of children in three groups matched for mental age. They consisted of 80 typically developing (TD)3–7 year old children, 62 children with DS aged 7–15 years, and 54 children with moderate ID aged 7–15 years. Parents completed the 37-item EZ-Personality Questionnaire (EZPQ; Zigler et al., 2002), a measure of personality-motivational functioning. Results: There were significant differences between TD children and those with ID on all EZPQ scales. In most respects children with DS did not differ significantly from others with moderate ID, although they were rated as having greater expectancy of success and fewer negative reactions. Conclusion: The finding that children with DS are less motivated than TD children of the same mental age is consistent with previous studies in which parents have rated motivation. It seems, however, that motivation difficulties are associated with ID more generally, rather than being specific to those with DS. The study raises questions about phenotypic versus experiential effects on motivation for children with ID.