Experimental evaluation of position control methods for hydraulic systems

Presents a unified and systematic assessment of ten position control strategies for a hydraulic servo system with single-ended cylinder driven by a proportional directional control valve. We aim at identifying those methods that achieve better tracking, have a low sensitivity to system uncertainties, and offer a good balance between development effort and end results. A formal approach for solving this problem relies on several practical metrics, which is introduced herein. Their choice is important, as the comparison results between controllers can vary significantly, depending on the selected criterion. Apart from the quantitative assessment, we also raise aspects which are difficult to quantify, but which must stay in attention when considering the position control problem for this class of hydraulic servo systems.

Optimising figure of merit for phonetic spoken term detection

This paper introduces a novel technique to directly optimise the Figure of Merit (FOM) for phonetic spoken term detection. The FOM is a popular measure of sTD accuracy, making it an ideal candiate for use as an objective function. A simple linear model is introduced to transform the phone log-posterior probabilities output by a phe classifier to produce enhanced log-posterior features that are more suitable for the STD task. Direct optimisation of the FOM is then performed by training the parameters of this model using a non-linear gradient descent algorithm. Substantial FOM improvements of 11% relative are achieved on held-out evaluation data, demonstrating the generalisability of the approach.

Heavy vehicle suspensions : testing and analysis

Transport regulators consider that, with respect to pavement damage, heavy vehicles (HVs) are the riskiest vehicles on the road network. That HV suspension design contributes to road and bridge damage has been recognised for some decades. This thesis deals with some aspects of HV suspension characteristics, particularly (but not exclusively) air suspensions. This is in the areas of developing low-cost in-service heavy vehicle (HV) suspension testing, the effects of larger-than-industry-standard longitudinal air lines and the characteristics of on-board mass (OBM) systems for HVs. All these areas, whilst seemingly disparate, seek to inform the management of HVs, reduce of their impact on the network asset and/or provide a measurement mechanism for worn HV suspensions. A number of project management groups at the State and National level in Australia have been, and will be, presented with the results of the project that resulted in this thesis. This should serve to inform their activities applicable to this research. A number of HVs were tested for various characteristics. These tests were used to form a number of conclusions about HV suspension behaviours. Wheel forces from road test data were analysed. A “novel roughness” measure was developed and applied to the road test data to determine dynamic load sharing, amongst other research outcomes. Further, it was proposed that this approach could inform future development of pavement models incorporating roughness and peak wheel forces. Left/right variations in wheel forces and wheel force variations for different speeds were also presented. This led on to some conclusions regarding suspension and wheel force frequencies, their transmission to the pavement and repetitive wheel loads in the spatial domain. An improved method of determining dynamic load sharing was developed and presented. It used the correlation coefficient between two elements of a HV to determine dynamic load sharing. This was validated against a mature dynamic loadsharing metric, the dynamic load sharing coefficient (de Pont, 1997). This was the first time that the technique of measuring correlation between elements on a HV has been used for a test case vs. a control case for two different sized air lines. That dynamic load sharing was improved at the air springs was shown for the test case of the large longitudinal air lines. The statistically significant improvement in dynamic load sharing at the air springs from larger longitudinal air lines varied from approximately 30 percent to 80 percent. Dynamic load sharing at the wheels was improved only for low air line flow events for the test case of larger longitudinal air lines. Statistically significant improvements to some suspension metrics across the range of test speeds and “novel roughness” values were evident from the use of larger longitudinal air lines, but these were not uniform. Of note were improvements to suspension metrics involving peak dynamic forces ranging from below the error margin to approximately 24 percent. Abstract models of HV suspensions were developed from the results of some of the tests. Those models were used to propose further development of, and future directions of research into, further gains in HV dynamic load sharing. This was from alterations to currently available damping characteristics combined with implementation of large longitudinal air lines. In-service testing of HV suspensions was found to be possible within a documented range from below the error margin to an error of approximately 16 percent. These results were in comparison with either the manufacturer’s certified data or test results replicating the Australian standard for “road-friendly” HV suspensions, Vehicle Standards Bulletin 11. OBM accuracy testing and development of tamper evidence from OBM data were detailed for over 2000 individual data points across twelve test and control OBM systems from eight suppliers installed on eleven HVs. The results indicated that 95 percent of contemporary OBM systems available in Australia are accurate to +/- 500 kg. The total variation in OBM linearity, after three outliers in the data were removed, was 0.5 percent. A tamper indicator and other OBM metrics that could be used by jurisdictions to determine tamper events were developed and documented. That OBM systems could be used as one vector for in-service testing of HV suspensions was one of a number of synergies between the seemingly disparate streams of this project.

Compliance with international financial reporting standards (IFRS) and the value relevance of accounting information in emerging stock markets : evidence from Kuwait

Since the 1960s, the value relevance of accounting information has been an important topic in accounting research. The value relevance research provides evidence as to whether accounting numbers relate to corporate value in a predicted manner (Beaver, 2002). Such research is not only important for investors but also provides useful insights into accounting reporting effectiveness for standard setters and other users. Both the quality of accounting standards used and the effectiveness associated with implementing these standards are fundamental prerequisites for high value relevance (Hellstrom, 2006). However, while the literature comprehensively documents the value relevance of accounting information in developed markets, little attention has been given to emerging markets where the quality of accounting standards and their enforcement are questionable. Moreover, there is currently no known research that explores the association between level of compliance with International Financial Reporting Standards (IFRS) and the value relevance of accounting information. Motivated by the lack of research on the value relevance of accounting information in emerging markets and the unique institutional setting in Kuwait, this study has three objectives. First, it investigates the extent of compliance with IFRS with respect to firms listed on the Kuwait Stock Exchange (KSE). Second, it examines the value relevance of accounting information produced by KSE-listed firms over the 1995 to 2006 period. The third objective links the first two and explores the association between the level of compliance with IFRS and the value relevance of accounting information to market participants. Since it is among the first countries to adopt IFRS, Kuwait provides an ideal setting in which to explore these objectives. In addition, the Kuwaiti accounting environment provides an interesting regulatory context in which each KSE-listed firm is required to appoint at least two external auditors from separate auditing firms. Based on the research objectives, five research questions (RQs) are addressed. RQ1 and RQ2 aim to determine the extent to which KSE-listed firms comply with IFRS and factors contributing to variations in compliance levels. These factors include firm attributes (firm age, leverage, size, profitability, liquidity), the number of brand name (Big-4) auditing firms auditing a firm’s financial statements, and industry categorization. RQ3 and RQ4 address the value relevance of IFRS-based financial statements to investors. RQ5 addresses whether the level of compliance with IFRS contributes to the value relevance of accounting information provided to investors. Based on the potential improvement in value relevance from adopting and complying with IFRS, it is predicted that the higher the level of compliance with IFRS, the greater the value relevance of book values and earnings. The research design of the study consists of two parts. First, in accordance with prior disclosure research, the level of compliance with mandatory IFRS is examined using a disclosure index. Second, the value relevance of financial statement information, specifically, earnings and book value, is examined empirically using two valuation models: price and returns models. The combined empirical evidence that results from the application of both models provides comprehensive insights into value relevance of accounting information in an emerging market setting. Consistent with expectations, the results show the average level of compliance with IFRS mandatory disclosures for all KSE-listed firms in 2006 was 72.6 percent; thus, indicating KSE-listed firms generally did not fully comply with all requirements. Significant variations in the extent of compliance are observed among firms and across accounting standards. As predicted, older, highly leveraged, larger, and profitable KSE-listed firms are more likely to comply with IFRS required disclosures. Interestingly, significant differences in the level of compliance are observed across the three possible auditor combinations of two Big-4, two non-Big 4, and mixed audit firm types. The results for the price and returns models provide evidence that earnings and book values are significant factors in the valuation of KSE-listed firms during the 1995 to 2006 period. However, the results show that the value relevance of earnings and book values decreased significantly during that period, suggesting that investors rely less on financial statements, possibly due to the increase in the available non-financial statement sources. Notwithstanding this decline, a significant association is observed between the level of compliance with IFRS and the value relevance of earnings and book value to KSE investors. The findings make several important contributions. First, they raise concerns about the effectiveness of the regulatory body that oversees compliance with IFRS in Kuwait. Second, they challenge the effectiveness of the two-auditor requirement in promoting compliance with regulations as well as the associated cost-benefit of this requirement for firms. Third, they provide the first known empirical evidence linking the level of IFRS compliance with the value relevance of financial statement information. Finally, the findings are relevant for standard setters and for their current review of KSE regulations. In particular, they highlight the importance of establishing and maintaining adequate monitoring and enforcement mechanisms to ensure compliance with accounting standards. In addition, the finding that stricter compliance with IFRS improves the value relevance of accounting information highlights the importance of full compliance with IFRS and not just mere adoption.

Raising the Standards: An Integrated Approach to Promoting Professional Standards and Avoiding Professional Criminality

Crime in the Professions critically examines the nature and extent of crime and deviance in the professions and how it should be dealt with. The increasing professionalization of the work force and the changes in the way in which professionals carry out their work, such as through the use of computing and communications technology, have created new opportunities for professionals to break the law. Looking in detail at the nature and extent of crime committed by professionals such as doctors, accountants and nurses the book offers some innovative solutions on preventing and controlling professional crime. In addition to examining the nature and extent of crime in the professions, it also addresses some critical issues of regulation for the future, concerning new and emerging professional groups and issues relating to emerging technologies.

Standards, teacher judgement and moderation in contexts of national curriculum and assessment reform

This paper puts forward a proposal for reviewing the role and purpose of standards in the context of national curriculum and assessment reform more generally. It seeks to commence the much-needed conversation about standards in the work of teachers as distinct from large-scale testing companies and the policy personnel responsible for reporting. Four key conditions that relate to the effective use of standards to measure improvement and support learning are analysed: clarity about purpose and function; understanding of the representation of standards; moderation practice; and the assessment community. The Queensland experience of the use of standards, teacher judgement and moderation is offered to identify what is educationally preferable in terms of their use and their relationships to curriculum, improvement and accountability. The article illustrates how these practices have recently been challenged by emerging political constraints related to the Australian Government’s implementation of national testing and national partnership funding arrangements tied to the performance of students at or below minimum standards.

Role and purpose of standards in the context of national curriculum and assessment reform for accountability, improvement and equity in student learning

In this article our starting point is the current context of national curriculum change and intense speculation about the assessment, standards and reporting. It is written against a background of accountability measures and improvement imperatives, and focuses attention on standards as offering representations of quality. We understand standards to be constructs that aim to achieve public credibility and utility. Further, they can be examined for the purposes they seek to serve and also their expected functions. Fitness for purpose is therefore a useful notion in considering the nature of standards. Our interest in the discussion is the ‘fit’ between how standards are formulated and how they are used in practice, by whom and for what purposes. A related interest is in the matter of how standards can be harnessed to realise improvement.

Axial magnetic bearing development for the BiVACOR Rotary BiVAD/TAH

A suspension system for the BiVACOR biventricular assist device (BiVAD) has been developed and tested. The device features two semi-open centrifugal impellers mounted on a common rotating hub. Flow balancing is achieved through the movement of the rotor in the axial direction. The rotor is suspended in the pump casings by an active magnetic suspension system in the axial direction and a passive hydrodynamic bearing in the radial direction. This paper investigates the axial movement capacity of themagnetic bearing system and the power consumption at various operating points. The force capacity of the passive hydrodynamic bearing is investigated using a viscous glycerol solution. Axial rotor movement in the range of ±0.15 mm is confirmed and power consumption is under 15.5 W. The journal bearing is shown to stabilize the rotor in the radial direction at the required operating speed. Magnetic levitation is a viable suspension technique for the impeller of an artificial heart to improve device lifetime and reduce blood damage.

Group segmentation during object tracking using optical flow discontinuities

Within a surveillance video, occlusions are commonplace, and accurately resolving these occlusions is key when seeking to accurately track objects. The challenge of accurately segmenting objects is further complicated by the fact that within many real-world surveillance environments, the objects appear very similar. For example, footage of pedestrians in a city environment will consist of many people wearing dark suits. In this paper, we propose a novel technique to segment groups and resolve occlusions using optical flow discontinuities. We demonstrate that the ratio of continuous to discontinuous pixels within a region can be used to locate the overlapping edges, and incorporate this into an object tracking framework. Results on a portion of the ETISEO database show that the proposed algorithm results in improved tracking performance overall, and improved tracking within occlusions.

Standards-driven reform years 1-10 : moderation an optional extra?

While externally moderated standards-based assessment has been practised in Queensland senior schooling for more than three decades, there has been no such practice in the middle years. With the introduction of standards at state and national levels in these years, teacher judgement as developed in moderation practices is now vital. This paper argues, that in this context of assessment reform, standards intended to inform teacher judgement and to build assessment capacity are necessary but not sufficient for maintaining teacher and public confidence in schooling. Teacher judgement is intrinsic to moderation, and to professional practice, and can no longer remain private. Moderation too is intrinsic to efforts by the profession to realise judgements that are defensible, dependable and open to scrutiny. Moderation can no longer be considered an optional extra and requires system-level support especially if, as intended, the standards are linked to system-wide efforts to improve student learning. In presenting this argument we draw on an Australian Research Council funded study with key industry partners (the Queensland Studies Authority and the National Council for Curriculum and Assessment of the Republic of Ireland). The data analysed included teacher interview data and additional teacher talk during moderation sessions. These were undertaken during the initial phase of policy development. The analysis identified those issues that emerge in moderation meetings that are designed to reach consistent, reliable judgements. Of interest are the different ways in which teachers talked through and interacted with one another to reach agreement about the quality of student work in the application of standards. There is evidence of differences in the way that teachers made compensations and trade-offs in their award of grades, dependent on the subject domain in which they teach. This article concludes with some empirically derived insights into moderation practices as policy and social events.

The centrality of teachers’ judgement practice in assessment : a study of standards in moderation

There is a strong quest in several countries including Australia for greater national consistency in education and intensifying interest in standards for reporting. Given this, it is important to make explicit the intended and unintended consequences of assessment reform strategies and the pressures to pervert and conform. In a policy context that values standardisation, the great danger is that the technical, rationalist approaches that generalise and make superficial assessment practices, will emerge. In this article, the authors contend that the centrality and complexity of teacher judgement practice in such a policy context need to be understood. To this end, we discuss and analyse recorded talk in teacher moderation meetings showing the processes that teachers use as they work with stated standards to award grades (A to E). We show how they move to and fro between (1) supplied textual artefacts, including stated standards and samples of student responses, (2) tacit knowledge of different types, drawing into the moderation, and (3) social processes of dialogue and negotiation. While the stated standards play a part in judgement processes, in and of themselves they are shown to be insufficient to account for how the teachers ascribe value and award a grade to student work in moderation. At issue is the nature of judgement as cognitive and social practice in moderation and the legitimacy (or otherwise) of the mix of factors that shape how judgement occurs.

Legislative proposals to codify directors' liability for insolvent trading in Hong Kong : a 10-year journey

Hong Kong is a modern global city with a reputation for well-regulated financial markets, but for years, the government had been trying to enact laws on corporate rescue procedures with relatively little success. It is under the pretext of the Global Financial Crisis, the threat of a future economic meltdown gave the Hong Kong government the impetus to revisit this issue. This third attempt to codify statutory obligations on directors’ liability for insolvent trading has been criticised for either setting the standards too high or low for directors trading whilst insolvent. There is also some reservation given the beliefs and values of directors in Chinese family-owned and controlled companies. These companies would most likely trade out the difficult times. Nevertheless, this does not negate from the fact that the enactment of corporate rescue procedures in Hong Kong in 2010 is a momentous achievement for the Hong Kong government.

Operation and control of hybrid microgrid with angle droop controller

This paper compares the performance of two droop control schemes in a hybrid microgrid. With presence of both converter interfaced and inertial sources, the droop controller share power in a decentralized fashion. Both the droop controllers facilitate reactive power sharing based on voltage droop. However in frequency droop control, the real power sharing depends on the frequency, while in angle droop control, it depends on output voltage angle. For converter interfaced sources this reference voltage is tracked while for inertial DG, reference power for the prime mover is calculated from the reference angle with the proposed angle control scheme. This coordinated control scheme shows significant improvement in system performance. The comparison with the conventional frequency droop shows that the angle control scheme shares power with much lower frequency deviation. This is a significant improvement particularly in a frequent load changing scenario.