Speech recognition using ad-hoc microphone arrays

While close talking microphones give the best signal quality and produce the highest accuracy from current Automatic Speech Recognition (ASR) systems, the speech signal enhanced by microphone array has been shown to be an effective alternative in a noisy environment. The use of microphone arrays in contrast to close talking microphones alleviates the feeling of discomfort and distraction to the user. For this reason, microphone arrays are popular and have been used in a wide range of applications such as teleconferencing, hearing aids, speaker tracking, and as the front-end to speech recognition systems. With advances in sensor and sensor network technology, there is considerable potential for applications that employ ad-hoc networks of microphone-equipped devices collaboratively as a virtual microphone array. By allowing such devices to be distributed throughout the users’ environment, the microphone positions are no longer constrained to traditional fixed geometrical arrangements. This flexibility in the means of data acquisition allows different audio scenes to be captured to give a complete picture of the working environment. In such ad-hoc deployment of microphone sensors, however, the lack of information about the location of devices and active speakers poses technical challenges for array signal processing algorithms which must be addressed to allow deployment in real-world applications. While not an ad-hoc sensor network, conditions approaching this have in effect been imposed in recent National Institute of Standards and Technology (NIST) ASR evaluations on distant microphone recordings of meetings. The NIST evaluation data comes from multiple sites, each with different and often loosely specified distant microphone configurations. This research investigates how microphone array methods can be applied for ad-hoc microphone arrays. A particular focus is on devising methods that are robust to unknown microphone placements in order to improve the overall speech quality and recognition performance provided by the beamforming algorithms. In ad-hoc situations, microphone positions and likely source locations are not known and beamforming must be achieved blindly. There are two general approaches that can be employed to blindly estimate the steering vector for beamforming. The first is direct estimation without regard to the microphone and source locations. An alternative approach is instead to first determine the unknown microphone positions through array calibration methods and then to use the traditional geometrical formulation for the steering vector. Following these two major approaches investigated in this thesis, a novel clustered approach which includes clustering the microphones and selecting the clusters based on their proximity to the speaker is proposed. Novel experiments are conducted to demonstrate that the proposed method to automatically select clusters of microphones (ie, a subarray), closely located both to each other and to the desired speech source, may in fact provide a more robust speech enhancement and recognition than the full array could.

Accounting information systems in a centrally planned economy : the case of the General Company for Pipelines (GCP)

The paper has a twofold purpose. First it highlights the importance of accounting information in the economic development of developing countries, with a particular focus on the nation of Libya. Secondly, using the case of Libya's General Company for Pipelines (GCP), it demonstrates that the use of accounting information to achieve economic development goals is determined to a large extent by the political/ideological setting in which it is generated. The study is based on a literature review and archival research, reinforced by a qualitative case study comprised of interviews, attendance at meetings and a study of internal documents. A study of The General Company for Pipelines (GCP) revealed that frequent politically driven changes in the structure and number of popular congresses and committees severely limited the use of accounting information, relegating it to a formal role. In consequence, accounting information had litle effect on stimulating economic development in Libya. This study focuses on one case study which does limit generalisability. However, it also suggests fruitful research areas considering the historic factors which have determined the accounting role in developing and planned economies. By providing insights about social factors which have determined the use of accounting in a planned economy, this study has implications for similar economies as they move towards a more globalised mode of operations which enhance the role of accounting in meeting economic development needs. If devleoping countries are to harness the potential of accounting aid in the achievement of their development plans, the social and political setting in which accounting has been conducted needs to be understood.

How nonprofit boards monitor, judge and influence organisational performance

The law and popular opinion expect boards of directors will actively monitor their organisations. Further, public opinion is that boards should have a positive impact on organisational performance. However, the processes of board monitoring and judgment are poorly understood, and board influence on organisational performance needs to be better understood. This thesis responds to the repeated calls to open the ‘black box’ linking board practices and organisational performance by investigating the processual behaviours of boards. The work of four boards1 of micro and small-sized nonprofit organisations were studied for periods of at least one year, using a processual research approach, drawing on observations of board meetings, interviews with directors, and the documents of the boards. The research shows that director turnover, the difficulty recruiting and engaging directors, and the administration of reporting, had strong impacts upon board monitoring, judging and/or influence. In addition, board monitoring of organisational performance was adversely affected by directors’ limited awareness of their legal responsibilities and directors’ limited financial literacy. Directors on average found all sources of information about their organisation’s work useful. Board judgments about the financial aspects of organisational performance were regulated by the routines of financial reporting. However, there were no comparable routines facilitating judgments about non-financial performance, and such judgments tended to be limited to specific aspects of performance and were ad hoc, largely in response to new information or the repackaging of existing information in a new form. The thesis argues that Weick’s theory of sensemaking offers insight into the way boards went about the task of understanding organisational performance. Board influence on organisational performance was demonstrated in the areas of: compliance; instrumental influence through service and through discussion and decision-making; and by symbolic, legitimating and protective means. The degree of instrumental influence achieved by boards depended on director competency, access to networks of influence, and understandings of board roles, and by the agency demonstrated by directors. The thesis concludes that there is a crowding out effect whereby CEO competence and capability limits board influence. The thesis also suggests that there is a second ‘agency problem’, a problem of director volition. The research potentially has profound implications for the work of nonprofit boards. Rather than purporting to establish a general theory of board governance, the thesis embraces calls to build situation-specific mini-theories about board behaviour.

Information sharing in the 21st century : progress and challenges

With the increasing threat of cyber and other attacks on critical infrastructure, governments throughout the world have been organizing industry to share information on possible threats. In Australia the Office of the Attorney General has formed Trusted Information Sharing Networks (TISN) for the various critical industries such as banking and electricity. Currently the majority of information for a TISN is shared at physical meetings. To meet cyber threats there are clearly limitations to physical meetings. Many of these limitations can be overcome by the creation of a virtual information sharing network (VISN). However there are many challenges to overcome in the design of a VISN both from a policy and technical viewpoint. We shall discuss some of these challenges in this talk.

Can an effective audit committee help to mitigate earnings management in Chinese firms listed in Hong Kong?

This paper attempts to determine whether the adoption of recommended corporate governance practices by Chinese firms is associated with less earnings management proxied by abnormal accruals. We examine the role of the audit committee and ownership concentration in preventing earnings management using Chinese firms listed in Hong Kong. The results of this preliminary analysis show that the frequency of audit committee meetings is associated with reduced levels of abnormal accruals, our measure of earnings management. We conclude that audit committee activity is an important factor in constraining the propensity of managers to engage in earnings management. In contrast, we find that the size of the audit committee is associated with increased levels of abnormal accruals and suggest that increasing the size of the audit committee creates information asymmetry between the audit committee and management that reduces the monitoring capacity of the audit committee. We do not find any association between audit committee independence, financial and industry experience, or ownership concentration and abnormal accruals.

Requirements for enhancing trust, security and integrity of GNSS location services

The paper describes a number of requirements for enhancing the trust of location acquisition from Satellite Navigation Systems, particularly for those applications where the location is monitored through a remote GNSS receiver. We discuss how the trust of a location acquisition could be propagated to an application through the use of a proposed tamper-­resistant GNSS receiver which quantifies the trust of a location solution from the signaling used (ie. P(Y) code, Galileo SOL, PRS, CS) and provides a cryptographic proof of this to a remote application. The tamper­-resistance state of the receiver is also included in this cryptographic proof.

Airborne particles and health

Much has been written about airborne particulate matter, and countless meetings, workshops and conferences have been held, both nationally and internationally, to address the many scientific challenges which they present, especially when one considers their effects on human health. Particles are a complex airborne pollutant, because of their many different characteristics and the many different ways in which they can be measured and detected. This article summarises the current state of knowledge on the effects of particulate matter and health, based primarily on epidemiological studies which focused on exposure to particle mass, and more recently, on particle number concentration.

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.

Mentor educators’ understandings of mentoring preservice primary teachers

Mentors are significant in shaping a preservice teacher’s practices. Developing common understandings about effective mentoring practices can assist the mentoring process. What are mentor educators’ practical ideas towards implementing a mentoring program? This mixed-method study involves surveys, questionnaires, and audio-taped focus group meetings on 14 mentor educators’ views on mentoring preservice primary teachers. This research aims to understand mentor educators’ motivations for mentoring, their views about what makes a good mentor, benefits for mentors, and issues or concerns for mentors and the mentoring process. It also focuses on determining professional development for mentors and troubleshooting potential problems. Findings revealed that these mentor educators were motivated into developing mentoring programs as a way to: (1) influence the quality of preservice teacher education (2) provide personal and professional development in mentoring, and (3) support mentors and the mentoring process within school settings. Outlining what makes a good mentor and benefits for mentors were consistent with the literature. However, these expert mentors also provided potential solutions (e.g., university support and professional development ideas) on issues such as knowing the mentee’s level of development and expectations, building a professional relationship prior to placement and the mentor’s dual role as confidant and assessor.

Betting on the underdog : bricolage as an engine of resource advantage

Resource-based theory posits that firms achieve high performance by controlling resources that are rare, valuable and costly for others to duplicate or work around. Yet scholars have been less successful understanding processes and behaviours by which firms develop such resources. We draw on the behavioral theory of bricolage from the entrepreneurship literature to suggest one such mechanism by which firms may develop such resource-based advantages. The core of our argument is that idiosyncratic bundling processes synonymous with bricolage behavior may create advantageous resource positions by (i) allowing resource constrained firms to allocate more of their limited resources to activities that they view as more strategically important, and (ii) increasing the difficulties other firms face in trying to imitate these advantages. Based on this reasoning we develop several hypotheses which we test in the context of several samples from a large, longitudinal, Australian study of new firm development. The results support our arguments that bricolage will improve a firms’ overall resource positions while generating more areas of strong resource advantage and fewer areas of strong resource disadvantage. We find little support, however, for our arguments that bricolage will make a firms’ key resource advantages more difficult for other firms to imitate. We find some support for our argument that the role of bricolage in creating resource advantages will be enhanced by the quality of the opportunity with which a firm is engaged.

Do strategy choices matter for nascent firms? Effectuation in the early stages of venture creation

This paper explores empirically effects of Effectuation on nascent firms’ performance. Three potential outcomes for nascent firms using different levels of effectuation and causation are investigated. Innovation, a measure of venture sophistication was introduced as a moderator. We examine a longitudinal random sample of 625 nascent firms collected over two years in Australia and provide support for our hypotheses. Results show that in situation of high uncertainty, nascent firms using effectuation are more likely to reach operational stage than their counterpart using causation.

Review of the progress in thin bed technology for masonry construction

Thin bed technology for clay/ concrete masonry is gaining popularity in many parts of the developed economy in recent times through active engagement of the industry with the academia. One of the main drivers for the development of thin bed technology is the progressive contraction of the professional brick and block laying workforce as the younger generation is not attracted towards this profession due to the general perception of the society towards manual work as being outdated in the modern digital economy. This situation has led to soaring cost of skilled labour associated with the general delay in completion of construction activities in recent times. In parallel, the advent of manufacturing technologies in producing bricks and blocks with adherence to specified dimensions and shapes and several rapid setting binders are other factors that have contributed to the development of thin bed technology. Although this technology is still emerging, especially for applications to earthquake prone regions, field applications are reported in Germany for over a few decades and in Italy since early 2000. The Australian concrete masonry industry has recently taken keen interest in pursuing research with a view to developing this technology. This paper presents the background information including review of literature and pilot studies that have been carried out to enable planning of the development of thin bed technology. The paper concludes with recommendations for future research.

Distinguishing forced versus discretionary replacements in new product diffusion models

In many product categories of durable goods such as TV, PC, and DVD player, the largest component of sales is generated by consumers replacing existing units. Aggregate sales models proposed by diffusion of innovation researchers for the replacement component of sales have incorporated several different replacement distributions such as Rayleigh, Weibull, Truncated Normal and Gamma. Although these alternative replacement distributions have been tested using both time series sales data and individual-level actuarial “life-tables” of replacement ages, there is no census on which distributions are more appropriate to model replacement behaviour. In the current study we are motivated to develop a new “modified gamma” distribution by two reasons. First we recognise that replacements have two fundamentally different drivers – those forced by failure and early, discretionary replacements. The replacement distribution for each of these drivers is expected to be quite different. Second, we observed a poor fit of other distributions to out empirical data. We conducted a survey of 8,077 households to empirically examine models of replacement sales for six electronic consumer durables – TVs, VCRs, DVD players, digital cameras, personal and notebook computers. This data allows us to construct individual-level “life-tables” for replacement ages. We demonstrate the new modified gamma model fits the empirical data better than existing models for all six products using both a primary and a hold-out sample.

Users verses IT: Understanding prejudice in information systems development project teams

This paper investigated the phenomenon of prejudice among ISD project members. We presented a theoretical discussion followed by one qualitative and one quantitative study. In the qualitative study, we interviewed different members of the project teams to understand the different types of prejudice possessed by team members. Results of this interview study led to the development of prejudice scales for IT members and users, which was used in the quantitative study. We surveyed 128 ISD teams and found that prejudice was related task and relationship conflict, satisfaction and willingness to work together in the future. Furthermore, prejudice exerts stronger influences on users than IT members in terms of increasing task and relationship conflicts and decreasing goal commitment.