RELT - Visualizing trees on mobile devices

The small screens on increasingly used mobile devices challenge the traditional visualization methods designed for desktops. This paper presents a method called "Radial Edgeless Tree" (RELT) for visualizing trees in a 2-dimensional space. It combines the existing connection tree drawing with the space-filling approach to achieve the efficient display of trees in a small geometrical area, such as the screen that are commonly used in mobile devices. We recursively calculate a set of non-overlapped polygonal nodes that are adjacent in the hierarchical manner. Thus, the display space is fully used for displaying nodes, while the hierarchical relationships among the nodes are presented by the adjacency (or boundary-sharing) of the nodes. It is different from the other traditional connection approaches that use a node-link diagram to present the parent-child relationships which waste the display space. The hierarchy spreads from north-west to south-east in a top-down manner which naturally follows the traditional way of human perception of hierarchies. We discuss the characteristics, advantages and limitations of this new technique and suggestions for future research. © Springer-Verlag Berlin Heidelberg 2007

VAS (Visual Analysis System): An information visualization engine to interpret World Wide Web structure

People increasingly encounter problems of interpreting and filtering mass quantities of information. The enormous growth of information systems on the World Wide Web has demonstrated that we need systems to filter, interpret, organize and present information in ways that allow users to use these large quantities of information. People need to be able to extract knowledge from this sometimes meaningful but sometimes useless mass of data in order to make informed decisions. Web users need to have some kind of information about the sort of page they might visit, such as, is it a rarely referenced or often-referenced page? This master\u27s thesis presents a method to address these problems using data mining and information visualization techniques

Temporal Treemaps for Visualizing Time Series Data

Treemap is an interactive graphical technique for visualizing large hierarchical information spaces using nested rectangles in a space filling manner. The size and color of the rectangles show data attributes and enable users to spot trends, patterns or exceptions. Current implementations of treemaps help explore time-invariant data. However, many real-world applications require monitoring hierarchical, time-variant data. This thesis extends treemaps to interactively explore time series data by mapping temporal changes to color attribute of treemaps. Specific contributions of this thesis include: · Temporal treemaps for exploring time series data through visualizing absolute or relative changes, animating them over time, filtering data items, and discovering trends using time series graphs. · The design and implementation of extensible software modules based on systems engineering methodologies and object-oriented approach. · Validation through five case studies: health statistics, web logs, production data, birth statistics, and help-desk tickets; future improvements identified from the user feedback

A usability approach to improving the user experience in web directories

PhDWeb directories are hierarchically organised website collections that offer users subjectbased access to the Web. They played a significant part in navigating the Web in the past but their role has been weakened in recent years due to their cumbersome expanding collections. This thesis presents a unified framework combining the advantages of personalisation and redefined directory search for improving the usability of Web directories. The thesis begins with an examination of classification schemes that identifies the rigidity of hierarchical classifications and their suitability for Web directories in contrast to faceted classifications. This leads on to an Ontological Sketch Modelling (OSM) case study which identifies the misfits affecting user navigation in Web directories from known rigidity issues. The thesis continues with a review of personalisation techniques and a discussion of the user search model of Web directories following the suggested directions of improvement from the case study. A proposed user-centred framework to improve the usability of Web directories which consists of an individual content-based personalisation model and a redefined search model is then implemented as D-Persona and D-Search respectively. The remainder of the thesis is concerned with a usability test of D-Persona and D-Search aimed at discovering the efficiency, effectiveness and user satisfaction of the solution. This involves an experimental design, test results and discussions for the comparative user study. This thesis extracts a formal definition of the rigidity of hierarchies from their characteristics and justifies why hierarchies are still better suited than facets in organising Web directories. Second, it identifies misfits causing poor usability in Web directories based on the discovered rigidity of hierarchies. Third, it proposes a solution to tackle the misfits and improve the usability of Web directories which has been experimentally proved to be successful

A Usability Approach to Improving the User Experience in Web Directories

Submitted for the degree of Doctor of Philosophy, Queen Mary, University of Londo

Visualisierung von Informationsräumen

Summary of the thesis topic: Visualization of information spaces For a user it is hard to recognize the relevance of documents based on a a textual information list, which is returned by a search engine after searching in the World Wide Web. Neither is he is able to discover the relevant information through navigating the document references, since the navigation does not occur in a closed space. The user has to browse through references of one document to the next, and does not always come back to the starting point. The user thereby loses the overview of the found documents. It becomes problematic to search information with several keywords. The proximity of the found documents for the individual search keyword is not clear from the result list. This is particularly disadvantageous if an indistinct information search is accomplished. A solution for this problem lies in the graphic representation of the information space (the document amount was determined with the search keywor). This work analyzes existing approaches of information visualization from different grounds in the practice, that are, however, limited on a pure graphic representation. Therefore, it is necessary to develop a new approach, that supports user representation and analysis of the set of results as well as providing the means for effective isolation of the actual interesting set of documents. In this work the requirements for the information search are analyzed and converted into a system model. The result is a design with the following characteristics: -- modular structure of the system, -- platform-independence, -- extensibility, -- the system contains open interfaces for integration with arbitrary search engines, -- filter mechanisms are integrated into the system, which permit an effective reduction of the set of documents. -- the system is able to work online and may also be used to analyse a once determined search result later, -- several variants of the graphic representation which can be used for the different types of information space are available. Due to the extensibility the system offers a special visualization and a filter combination for every user, which corresponds to his personal preferences. The user will formulate his need of information through his action in the space. He has the possibility to move through the space, to explore all objects exactly and to find the "interesting regions" of the information space. All integrated visualization techniques contain an own interaction model. This permits the selection and manipulation of the graphic information-objects in each case. The Interaction allows intensive investigation of the amount of information and its contents. The user can remove the information objects examined during the exploration or mark them as "relevant" and is able to find them later. Because of the combination of visualization and a series of filter mechanisms the system supports both - the "precise search" (for a specific document) and the "indistinct search" (for topics or fields) - well. This work further describes the implementation of a prototype, which serves for the verification of the design draft. Experiments show, that the efficiency of the search for information can be increased by the use of the presented technologies.Für den Benutzer ist es schwer, in der textbasierten Informationssliste, die durch eine Suchmaschine nach einer Suche im World Wide Web geliefert wird, zu erkennen, welche Dokumente für ihn relevant sind. Er ist auch nicht in der Lage, durch das Navigieren anhand der Dokumentverweise die relevanten Informationen aufzufinden, da die Navigation nicht in einem Raum stattfindet. Der Benutzer geht anhand von Verweisen von einem Dokument zum anderen und nicht in jedem Fall führt ein Weg zum Ausgangspunkt zurück. Der Benutzer verliert dadurch den Überblick über die gefundenen Dokumente. Problematisch wird es bei der Suche von Informationen mit mehreren Suchbegriffen. Die Nähe der gefundenen Dokumente zu den einzelnen Suchbegriffen wird aus der Ergebnisliste nicht ersichtlich. Dies ist insbesondere dann nachteilig, wenn eine unscharfe Informationssuche durchgeführt wurde. Eine Lösung dieses Problems besteht in der grafischen Darstellung des Informationsraumes (die Dokumentenmenge, die mit den Suchbegriffen ermittelt wurde). Diese Arbeit analysiert zunächst bereits existierende Ansätze zur Informationsvisualisierung, die allerdings auf eine reine grafische Darstellung begrenzt sind und sich aus verschiedenen Gründen in der Praxis nicht durchgesetzt haben. Daher ist ein neuer Ansatz notwendig, der den Benutzer bei der Darstellung und der Analyse der Ergebnismenge unterstützt sowie ihm die Mittel zum effektiven Eingrenzen der tatsächlich interessanten Dokumentenmenge gibt. In dieser Arbeit werden die Anforderungen an die Informationssuche analysiert und diese in einem Systementwurf umgesetzt. Das Ergebnis ist ein Entwurf mit folgenden Eigenschaften: -- modularer Aufbau des Systems, -- plattformunabhängig, -- erweiterbar, -- das System verfügt über offene Schnittstellen zur Ankopplung an beliebige Suchmaschinen, -- im System sind Filtermechanismen integriert, die eine wirksame Reduktion der Dokumentenmenge gestatten, -- das System kann sowohl online arbeiten als auch zur späteren Analyse eines einmal ermittelten Suchergebnisses eingesetzt werden, -- es sind mehrere Varianten der grafischen Darstellung vorhanden, die für die verschiedenen Typen von Informationsräumen eingesetzt werden können. Aufgrund der Erweiterbarkeit kann das System perspektivisch jedem Benutzer eine Visualisierung und eine Filterkombination anbieten, die seinen persönlichen Preferenzen entspricht. Der Benutzer wird seine Informationsbedürfnisse durch seine Handlung im Raum formulieren. Er hat die Möglichkeit, sich durch den Raum zu bewegen, alle Objekte genau zu untersuchen und die "interessanten Regionen" des Informationsraums zu finden. Alle integrierten Visualisierungsverfahren beinhalten ein eigenes Interaktionsmodell. Dieses gestattet in jedem Fall die Selektion und Manipulation der grafischen Informations-Objekte. Die Interaktion ermöglicht das intensive Erforschen der Informationsmenge und ihrer Inhalte. Der Benutzer kann die während der Interaktion einmal untersuchten Informations-Objekte entfernen oder als "relevant" kennzeichnen und dadurch schnell wieder auffinden. Durch die Kombination von Visualisierung und einer Reihe von Filtermechanismen wird vom System sowohl die "zielgerichtete Suche" (nach einem ganz bestimmten Dokument) als auch die "unscharfe Suche" (nach Themen oder Gebieten) gut unterstützt. Diese Arbeit beschreibt weiterhin die Implementierung eines Prototyps, der zur Verifizierung des Entwurfs dient. Experimente zeigen, wie die Effizienz bei der Suche nach Informationen durch den Einsatz der vorgestellten Technologien gesteigert werden kann

Interactive visualisation tools for supporting taxonomists working practice.

The necessity for scientists and others to use consistent terminology has recently beenregarded as fundamental to advancing scientific research, particularly where data fromdisparate sources must be shared, compared or integrated. One area where there aresignificant difficulties with the quality of collected data is the field of taxonomicdescription. Taxonomic description lies at the heart of the classification of organismsand communication of ideas of biodiversity. As part of their working practice,taxonomists need to gather descriptive data about a number of specimens on aconsistent basis for individual projects. Collecting semantically well-defined structureddata could improve the clarity and comparability of such data. No tools howevercurrently exist to allow taxonomists to do so within their working practice.Ontologies are increasingly used to describe and define complex domain data. As a partof related research an ontology of descriptive terminology for controlling the storageand use of flowering plant description data was developed.This work has applied and extended model-based user interface developmentenvironments to utilise such an ontology for the automatic generation of appropriatedata entry interfaces that support semantically well defined and structured descriptivedata. The approach taken maps the ontology to a system domain model, which ataxonomist can then specialise using their domain expertise, for their data entry needs asrequired for individual projects. Based on this specialised domain knowledge, thesystem automatically generates appropriate data entry interfaces that capture dataconsistent with the original ontology. Compared with traditional model-based userautomatic interface development environments, this approach also has the potential toreduce the labour requirements for the expert developer.The approach has also been successfully tested to generate data entry interfaces basedon an XML schema for the exchange of biodiversity datasets