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.

Case study: A holistic approach to embedding technology in curriculum design and planning processes

Case study on the Heart of Worcestershire College and how they are meeting the FELTAG recommendation of achieving a 10% wholly online component of all programmes from September 2015

Region-based Mixture of Gaussians Modelling for Foreground Detection in Dynamic Scenes

One of the most widely used techniques in computer vision for foreground detection is to model each background pixel as a Mixture of Gaussians (MoG). While this is effective for a static camera with a fixed or a slowly varying background, it fails to handle any fast, dynamic movement in the background. In this paper, we propose a generalised framework, called region-based MoG (RMoG), that takes into consideration neighbouring pixels while generating the model of the observed scene. The model equations are derived from Expectation Maximisation theory for batch mode, and stochastic approximation is used for online mode updates. We evaluate our region-based approach against ten sequences containing dynamic backgrounds, and show that the region-based approach provides a performance improvement over the traditional single pixel MoG. For feature and region sizes that are equal, the effect of increasing the learning rate is to reduce both true and false positives. Comparison with four state-of-the art approaches shows that RMoG outperforms the others in reducing false positives whilst still maintaining reasonable foreground definition. Lastly, using the ChangeDetection (CDNet 2014) benchmark, we evaluated RMoG against numerous surveillance scenes and found it to amongst the leading performers for dynamic background scenes, whilst providing comparable performance for other commonly occurring surveillance scenes.

New students, new learning, new environments in higher education : literacies in the digital age

Information literacy is developing new meanings and importance in the online age of teaching and learning in higher education. Information literacy, as a highly prized graduate attribute, is related to the development of lifelong learning capacities. Its strong re-emergence in the form of digital literacy in the context of major online developments at Deakin University is considered through four cases. In each case the reader is asked to consider how the teaching staff members have conceived critical discipline-based information and digital literacies, how these conceptions are related to desired learning outcomes, the types of digital and online environments designed to support the development of these literacies, and how each one contributes to the development of lifelong learning capacities. Information and digital literacy is enlivened through being situated in broader understandings of new generations of learners, new forms of learning and new e-supported learning environments. Educational design, evaluation, research and technology implications of these new types of digital and online-based teaching and learning environments are finally examined.

River pilots for time`s flow: identifying factors to guide on-line distance education students in the use of their learning time

This research draws on recent studies of student time perception and use.
Case studies are used contrast the time use experiences of tertiary distance
education (on-line) students with tertiary students studying in traditional faceto-face classes with an online component. Previous studies and experience highlight a mismatch between the measurable and hence ”real” amount of time students spend at their computer and online, with the perceived” (and resented) time spent in online learning. This study uses investigates the recognition and application of factors affecting student perception of time spent in studying and learning online. It also compares the effectiveness of these factors when applied to distance education based wholly online classes, and face-to-face classes with an online component.
Some of the factors were measurably successful in reducing students’
perceptions of time “wasted” online, while others produced considerable
insight into face-to-face students perceptions of time used in study. The
factors included much greater focus on the person who was a student and
their expectations and time/life experiences while learning; the support and
use of alternative technologies such as mobile phones as learning and
communication too; a higher level of administrative and academic technical
support for the students; convergence of delivery methods; and strategic
involvement of teaching staff in design and delivery of learner management
systems.

Using social software to support the teaching of IT professional practice

Social software has been used to support problem-based learning activities in a wholly online information technology (IT) professional practice course at Deakin University since 2006. When the course was first delivered, the authentic learning environment was a website, with an intranet and team forums created in Drupal, the open source content management system (CMS). Although this environment was suitable, feedback from students and teaching staff highlighted areas where improvements could be made. In the second year of the course, Joomla!, the open source CMS, in combination with Simple Machines Forum (SMF), the open source online discussion community software, was used to provide the website, as well as the intranet and team forums respectively. Feedback in 2007 was more positive, suggesting that the Joomla!-SMF social software combination and the features implemented, improved the learning and teaching experience in comparison to the 2006 version of the course.

An examination of the role of the e-tutor

As online learning environments continue to evolve, both teachers and students need to adapt to make the most of opportunities afforded by these environments for teaching and learning. The focus of this paper is on the changing role undertaken by tutors in online learning environments. We present a brief review of the current perspectives on the roles and responsibilities suggested for the e-tutor for effective teaching, and then report on a study where roles of e-tutors in a large wholly online unit were examined. The study supports the view that although the role of the e-tutor is similar to that of the face to face tutor in some respects, there are sufficient differences to make e-tutoring challenging to those who have not undertaken such online activities previously. Ongoing professional development is required to meet the changing demands of the technological environment, as well as the changing needs of
students.

The social side of social media : technology or collaboration?

This paper discusses how course design may draw upon social media in order to teach students appropriate skills for a network society in the context of team-work based learning. The emphasis is not upon web 2.0 and social media as inherently suited to providing educational solutions, but upon the ways in which they can be adapted by course designers within the framework of explicit learning objectives. More specifically, we provide a case study of how the use of social media in a blended or wholly-online learning environment provides affordances for team-based collaborative learning, especially when incorporated within a course design that encourages independent, self-directed and authentic learning. This paper argues we need to assess the social aspects of social media, rather than upon the technological, that is, avoid the fetishisation of 'apps,' through the creation of assessment that alternately foregrounds a critical appraisal of web 2.0 technologies and places onus upon the students to develop, with guidance, teamwork skills and processes. We provide an example of how it is possible to integrate web 2.0 technologies into their learning processes and assessment, in order to teach about the realities of collaborating with others in small teams in a work environment increasingly mediated by the Internet. In order to achieve these learning outcomes, course design needs to balance scaffolding with the need to place the imperative for learning specific content and skills upon the students, the latter through the provision of assessment outcomes and resources that the students need to work towards together.

The systematic influences on student evaluation of teaching in engineering education

BACKGROUND Student evaluation of teaching (SET) has a long history, has grown in prevalence and importance over a period of decades, and is now common-place in many universities internationally. SET data are collected for a range of purposes, including: as diagnostic feedback to improve the quality of teaching and learning; as an input to staff performance management processes and personnel decisions such as promotion for staff; to provide information to prospective students in their selection of courses and programs; and as a source of data for research on teaching. Rovai et al. (2006) report that while SET research provides mixed results, there is evidence that, for course-related factors, smaller classes are rated more favourably than large classes, upper-year-level classes are rated more favourably than lower-year classes, and that there are rating differences between discipline areas. While additional course-related factors are also noted, other reviews of the literature on SET also identify these three factors as commonly reported systematic influences on SET ratings. The School of Engineering at Deakin University in Australia offers undergraduate and postgraduate engineering programs, and these programs are delivered in both on-campus and off-campus modes.PURPOSEThe paper presents a quantitative investigation of SET data for the School of Engineering at Deakin University to identify whether the commonly reported systematic influences on SET ratings of class size and year level are also observed here. The influence of online mode of offer is also explored.DESIGN/METHOD Deakin University’s Student Evaluation of Teaching and Units (SETU) questionnaire is administered to students enrolled in every unit of study every time that unit is offered, unless it is specially exempted. Following data collation, summary results are reported via a public website. The publicly available SETU data for all School of Engineering units of study were collected for a two year period. The collected data were subjected to analysis of variance (ANOVA) analysis to identify any significant systematic influences on mean student SETU ratings.RESULTS SETU data from 100 separate units of study over the two year period were collected, representing 3375 sets of SETU ratings, and covering unit enrolment sizes from 12 to 462 students. Although this was a modest sized investigation, significantly higher mean ratings for some SETU items were observed for units with small enrolments, for postgraduate level units compared to undergraduate level units, and for units offered in conventional mode compared to online mode of offer. The presence of the commonly observed systematic influences on SET ratings was confirmed.CONCLUSIONS While the use of SET data may have originally been primarily for formative purposes to improve teaching and learning, they are also increasingly used for summative judgements of teaching quality and teaching staff performance that have implications for personnel decision making. There may be an acceptance of the need for SET, however there remains no universal consensus as to what constitutes quality in university teaching and learning, and the increasing use of SET for high-stakes decision making puts pressure on institutions to ensure that their SET practices are sound, equitable and defensible.

A desterritorialização da redação no jornalismo contemporâneo

The displacement of writing emerged in urban centers due to its investment in technology and has been developed in major newspapers around the world. With the advent of the internet and technological development, the writing went from analog to digital. That made it no longer required the presence of the journalist in the physical redaction means modifying the various management structures of a writing routine and professional. This happened to capture, edit and distribute your notes, news and reports in online mode. This monograph aims to understand and define the macro change of virtualization in journalism, considering the stages of production of Le Monde Diplomatique, a newspaper whose writing is in process of deterritorialization, the people involved in this activity and the resources used and contributing to the debate on new forms of organization of an editorial environment

Asking sensitive questions: Possibilities and limits of randomized response and other techniques in different survey modes

In our project within the DFG Priority Programme on Survey Methodology (SPP 1292) we conducted various methodological studies on survey techniques for asking sensitive questions. For example, we compared results from the randomized response technique (RRT) to true known data in a validation study, developed and evaluated implementations of the RRT for CATI and online mode, and compared the performance of the RRT to competing approaches. In our talk, we will give an overview of the studies conducted in this project and will present our key findings. Furthermore, we will identify open research questions and give guidelines for future research on asking sensitive questions.

Tratamiento de imágenes de mineral acarreado post-voladura. Análisis de curvas granulométricas y comparativa mediante sistemasplit on-line y Split desktop: automático y manual

En este proyecto se han analizado distintas imágenes de fragmentos de rocas de distintas granulometrías correspondientes a una serie de voladuras de una misma cantera. Cada una de las voladuras se componen de 20 imágenes. A posteriori utilizando el programa Split Desktop en su versión 3.1, se delimitaron los fragmentos de roca de los que está compuesta la imagen, obteniéndose posteriormente la curva granulométrica correspondiente a dicha imagen. Una vez se calculan las curvas granulométricas correspondientes a cada imagen, se calcula la curva media de todas ellas, pudiéndose considerar por tanto la curva media de cada voladura. Se han utilizado las distintas soluciones del software, manual, online y automático, para realizar los análisis de dichas imágenes y a posteriori comparar sus resultados. Dichos resultados se muestran a través de una serie de gráficos y tablas que se explican con detalle para la comprensión del estudio. De dichos resultados es posible afirmar que, el tratamiento de imágenes realizado de manera online y automático por Split, desemboca en el mismo resultado, al no haber una diferencia estadística significativa. Por el contrario, el sistema manual es diferente de los otros dos, no pudiéndose afirmar cual es mejor de los dos. El manual depende del operario que trabaje las imágenes y el online de los ajustes realizados y por tanto, ambos tienen ciertas incertidumbres difíciles de solucionar. Abstract In this project, different images of rock fragments of different grain sizes corresponding to a series of blasts from the same quarry have been analyzed. To study each blast, 20 images has been used and studied with the software Split Desktop 3.1. Rock fragments from each image has been delimitated with the software, obtaining a grading curve of each one. Once these curves are calculated, the mean curve of these data set is obtained and can be considered the mean curve of each blast. Different software solutions as manual, online and automatic, has been used for the analysis of these images. Then the results has been compared between them. These results are shown through a series of graphs and tables, that are explained in detail, to enhance the understanding of the study. From these results, it can be said that the image processing with online and automatic options from Split, leads to the same result, after an statistical study. On the contrary, the manual Split mode is different from the others; however is not possible to assert what will be the best. The manual Split mode depends on the operator ability and dedication, although the online mode depends on the software settings, so therefore, both have some uncertainties that are difficult to solve.

Der Lauff grosser Verèanderungen nach Orient auss verschiedener Cometen Bezeichnung Astrologicáe /

Insect damage has caused some loss of legibility throughout text.

Official gazette of the United States Patent and Trademark Office.

Continued online.

List of pictures at the seat of T.B. Brydges Barrett, Esq., at Lee Priory, in the county of Kent.

Wood-engraved vignettes, tail-pieces, initials.