1,720,969 research outputs found
Segmentation, Feature Extraction & Autoimmune Clustering for Foreground-background Image Retrieval
No full textIn our digital era, many attempts in remote sensing, fashion, crime prevention, publishing, medicine, architecture and bio-medicine have resulted in a large number of image data sets. Traditional methods to search and retrieve from these data sets are gradually being replaced by state-of-the-art and modern techniques such as content based image retrieval. Retrieving images through extracting contents as a feature and a similarity measure is one of the most challenging applications of computer vision. Due to the increasing number of images with different varieties and types, the traditional content based image retrieval systems are unable to properly exploit the content information of images for retrieval. Thus, extracting relevant features of images and finding a measure of image similarity that returns appropriate relationships is challenging. Content Based Image Retrieval (CBIR) is one of the open problems which still needs much more research effort to completely replace traditional retrieval systems. Feature extraction based on colour, texture, shape and etc. which has been done locally or globally for an image is one of the main parts of CBIR. Image segmentation, which extracts objects from the background and partitioning an image into several regions, helps facilitate feature extraction based on shapes or region of interest (ROI).Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of IInformation and Communication TechnologyScience, Environment, Engineering and TechnologyFull Tex
Content-Based Retrieval of Digital Video
No full textIn the next few years consumers will have access to large amounts of video and image data either
created by themselves with digital video and still cameras or by having access to other image
and video content electronically. Existing personal computer hardware and software has not been
designed to manage large quantities of multimedia content. As a result, research in the area of
content-based video retrieval (CBVR) has been underway for the last fifteen years. This research
aims to improve CBVR by providing an accurate and reliable shape-colour representation and
by providing a new 3D user interface called DomeWorld for the efficient browsing of large video
databases. Existing feature extraction techniques designed for use in large databases are typically simple
techniques as they must conform to the limited processing and storage constraints that are exhibited
by large scale databases. Conversely, more complex feature extraction techniques provide higher level
descriptions of the underlying data but are time consuming and require large amounts of
storage making them less useful for large databases. In this thesis a technique for medium to high level
shape representation is presented that exhibits efficient storage and query performance. The
technique uses a very accurate contour detection system that incorporates a new asymmetry edge
detector which is shown to perform better than other contour detection techniques combined with
a new summarisation technique to efficiently store contours. In addition, contours are represented
by histograms further reducing space requirements and increasing query performance. A new type
of histogram is introduced called the fuzzy histogram and is applied to content-based retrieval
systems for the first time. Fuzzy histograms improve the ranking of query results over non-fuzzy
techniques especially in low bin-count histogram configurations. The fuzzy contour histogram
approach is compared with an exhaustive contour comparison technique and is found to provide
equivalent or better results. A number of colour distribution representation techniques were
investigated for integration with the contour histogram and the fuzzy HSV histogram was found to
provide the best performance. When the colour and contour histograms were integrated less overall bins
were required as each histogram compensates for the other’s weaknesses. The result is that only a quarter of the bins
were required than either colour or contour histogram alone further reducing query times and
storage requirements. This research also improves the user experience with a new user interface called
DomeWorld that uses three-dimensional translucent domes. Existing user interfaces are either designed for
image databases, for browsing videos, or for browsing large non-multimedia data sets. DomeWorld
is designed to be able to browse both image and video databases through a number of innovative
techniques including hierarchical clustering, radial space-filling layout of nodes, three-dimensional
presentation, and translucent domes that allow the hierarchical nature of the data to be viewed
whilst also seeing the relationship between child nodes a number of levels deep.
A taxonomy of existing image, video, and large data set user interfaces is presented and the
proposed user interface is evaluated within the framework. It is found that video database user
interfaces have four requirements: context and detail, gisting, clustering, and integration of video
and images. None of the 27 evaluated user interfaces satisfy all four requirements. The DomeWorld
user interface is designed to satisfy all of the requirements and presents a step forward in CBVR
user interaction. This thesis investigates two important areas of CBVR, structural indexing and user
interaction, and presents techniques which advance the field. These two areas will become very important in
the future when users must access and manage large collections of image and video content.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Information TechnologyScience, Environment, Engineering and TechnologyFull Tex
A Novel Framework to Describe Technical Accessibility of Open Data
No full textOpen Data is a recent and important movement that has economic, social, and political benefits. Despite a lot of attention in literature there are still limitations with the existing Open Data frameworks in describing technical accessibility of Open Data. In this paper, at first, we review the emergence of Open Data and the current state of frameworks and standards. We also describe our progress and findings working with Open Data at the local, state, and federal level in Australia. We then present a new Open Data Accessibility Framework (ODAF), which more completely defines levels of Open Data accessibility, guiding data custodians to make data more accessible for Open Data consumers.Full Tex
Flipping a Programing Class to Improve Student Performance and Student Satisfaction
No full textFlipped classrooms are an instructional strategy that is becoming popular in educational contexts, particularly higher education. The principle of Flipped Classroom is that events that have traditionally taken place inside the classroom now take place outside the classroom and vice versa. Various studies have reported increased student performance and satisfaction after switching to a flipped classroom. However, most of these studies are based on students' perceptions of their own learning, not based on teachers' assessment of students' achievements. This article presents the results of flipping a computer programming course. It first describes how this course was flipped, then it presents the results of comparing the average marks awarded to students between those that took the course offering in flipped mode and those that took the course in the traditional mode. The comparison showed an increase in student performance in a flipped mode. Furthermore, the increase in student performance was sustained for 3 years, which is the full duration of this study. The comparison of student satisfaction showed an increase in student satisfaction in one campus, while the student satisfaction remained steady in another campus.No Full Tex
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Empirical Evaluation of Open Government Data Visualisations
No full textThe Open Government Data (OGD) movement has
seen governments around the world embrace the concept of
opening their data. However, the large amounts of data
released have not resulted in wide acceptance of the data by
end-users. This is partly due to the emphasis on machinereadability
rather than human-usability. Recently, some data
portals have included visualization techniques to make the
portals more usable. In this work, we report on user studies
conducted to evaluate different OGD visualization techniques.
The techniques were evaluated both quantitatively, through
recorded tasks, and qualitatively, through a post study survey.
We found that geographic map visualizations were reported by
users to provide the highest level of qualitative satisfaction,
which correlates with the quantitative results requiring the
shortest time to complete the tasks. This study provides
insights into empirical evaluation of visualization techniques to
aid OGD providers in making decisions about the best way to
present data in their portals.Griffith Sciences, School of Information and Communication TechnologyFull Tex
Empirical Evaluation of Data Visualizations by Non-Expert Users
No full textWith the increased release of Open Government
Data (OGD), several problems hinder the breakthrough of the
Open Data agenda into the mainstream. One of these problems
is the slow acceptance of OGD by non-expert end-users. They
do not have the technical skills and prefer a human-readable
format compared to the experts who demand machinereadable
data. Recently, some OGD portals added interactive
visualizations to ease the use of OGD by non-expert users.
However, the question of human-usability or what makes it
easier for non-experts to interact with OGD visualizations,
remains open. With the aim to answer this question, we report
results on the evaluation of OGD visualizations from the field
experiment conducted with non-expert users. We discuss
results and insights to inform designers and OGD providers.Griffith Sciences, School of Information and Communication TechnologyFull Tex
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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