Computer aids for the design of large scale integrated circuits.

The work described in this thesis is concerned with the development of CADIC (Computer Aided Design of Integrated Circuits), a suite of computer programs which allows the user to design integrated circuit layouts at the geometric level. Initially, a review of existing computer aids to integrated circuit design is carried out. Advantages and disadvantages of each computer aid is discused, and the approach taken by CADIC justified in the light of the review. The hardware associated with a design aid can greatly influence its performance and useability. For this reason, a critical review of available graphic terminals is also undertaken. The requirements, logistics, and operation of CADIC is then discussed in detail. CADIC provides a consise range of features to aid in the design and testing of integrated circuit layouts. The most important features are however CADIC's high efficiency in processing layout data, and the implementation of complete on-line design rule checking. Utilization of these features allows CADIC to substantially reduce the lengthy design turnaround time normally associated with manual design aids. Finally, the performance of CADIC is presented. Analysis of the results show that CADIC is very efficient at data processing, especially when small sections of the layout are considered. CADIC can also perform complete on-line design rule checking well within the time it takes the designer to start adding the next shape

The cockpit for the 21st century

Interactive surfaces are a growing trend in many domains. As one possible manifestation of Mark Weiser’s vision of ubiquitous and disappearing computers in everywhere objects, we see touchsensitive screens in many kinds of devices, such as smartphones, tablet computers and interactive tabletops. More advanced concepts of these have been an active research topic for many years. This has also influenced automotive cockpit development: concept cars and recent market releases show integrated touchscreens, growing in size. To meet the increasing information and interaction needs, interactive surfaces offer context-dependent functionality in combination with a direct input paradigm. However, interfaces in the car need to be operable while driving. Distraction, especially visual distraction from the driving task, can lead to critical situations if the sum of attentional demand emerging from both primary and secondary task overextends the available resources. So far, a touchscreen requires a lot of visual attention since its flat surface does not provide any haptic feedback. There have been approaches to make direct touch interaction accessible while driving for simple tasks. Outside the automotive domain, for example in office environments, concepts for sophisticated handling of large displays have already been introduced. Moreover, technological advances lead to new characteristics for interactive surfaces by enabling arbitrary surface shapes. In cars, two main characteristics for upcoming interactive surfaces are largeness and shape. On the one hand, spatial extension is not only increasing through larger displays, but also by taking objects in the surrounding into account for interaction. On the other hand, the flatness inherent in current screens can be overcome by upcoming technologies, and interactive surfaces can therefore provide haptically distinguishable surfaces. This thesis describes the systematic exploration of large and shaped interactive surfaces and analyzes their potential for interaction while driving. Therefore, different prototypes for each characteristic have been developed and evaluated in test settings suitable for their maturity level. Those prototypes were used to obtain subjective user feedback and objective data, to investigate effects on driving and glance behavior as well as usability and user experience. As a contribution, this thesis provides an analysis of the development of interactive surfaces in the car. Two characteristics, largeness and shape, are identified that can improve the interaction compared to conventional touchscreens. The presented studies show that large interactive surfaces can provide new and improved ways of interaction both in driver-only and driver-passenger situations. Furthermore, studies indicate a positive effect on visual distraction when additional static haptic feedback is provided by shaped interactive surfaces. Overall, various, non-exclusively applicable, interaction concepts prove the potential of interactive surfaces for the use in automotive cockpits, which is expected to be beneficial also in further environments where visual attention needs to be focused on additional tasks.Der Einsatz von interaktiven Oberflächen weitet sich mehr und mehr auf die unterschiedlichsten Lebensbereiche aus. Damit sind sie eine mögliche Ausprägung von Mark Weisers Vision der allgegenwärtigen Computer, die aus unserer direkten Wahrnehmung verschwinden. Bei einer Vielzahl von technischen Geräten des täglichen Lebens, wie Smartphones, Tablets oder interaktiven Tischen, sind berührungsempfindliche Oberflächen bereits heute in Benutzung. Schon seit vielen Jahren arbeiten Forscher an einer Weiterentwicklung der Technik, um ihre Vorteile auch in anderen Bereichen, wie beispielsweise der Interaktion zwischen Mensch und Automobil, nutzbar zu machen. Und das mit Erfolg: Interaktive Benutzeroberflächen werden mittlerweile serienmäßig in vielen Fahrzeugen eingesetzt. Der Einbau von immer größeren, in das Cockpit integrierten Touchscreens in Konzeptfahrzeuge zeigt, dass sich diese Entwicklung weiter in vollem Gange befindet. Interaktive Oberflächen ermöglichen das flexible Anzeigen von kontextsensitiven Inhalten und machen eine direkte Interaktion mit den Bildschirminhalten möglich. Auf diese Weise erfüllen sie die sich wandelnden Informations- und Interaktionsbedürfnisse in besonderem Maße. Beim Einsatz von Bedienschnittstellen im Fahrzeug ist die gefahrlose Benutzbarkeit während der Fahrt von besonderer Bedeutung. Insbesondere visuelle Ablenkung von der Fahraufgabe kann zu kritischen Situationen führen, wenn Primär- und Sekundäraufgaben mehr als die insgesamt verfügbare Aufmerksamkeit des Fahrers beanspruchen. Herkömmliche Touchscreens stellen dem Fahrer bisher lediglich eine flache Oberfläche bereit, die keinerlei haptische Rückmeldung bietet, weshalb deren Bedienung besonders viel visuelle Aufmerksamkeit erfordert. Verschiedene Ansätze ermöglichen dem Fahrer, direkte Touchinteraktion für einfache Aufgaben während der Fahrt zu nutzen. Außerhalb der Automobilindustrie, zum Beispiel für Büroarbeitsplätze, wurden bereits verschiedene Konzepte für eine komplexere Bedienung großer Bildschirme vorgestellt. Darüber hinaus führt der technologische Fortschritt zu neuen möglichen Ausprägungen interaktiver Oberflächen und erlaubt, diese beliebig zu formen. Für die nächste Generation von interaktiven Oberflächen im Fahrzeug wird vor allem an der Modifikation der Kategorien Größe und Form gearbeitet. Die Bedienschnittstelle wird nicht nur durch größere Bildschirme erweitert, sondern auch dadurch, dass Objekte wie Dekorleisten in die Interaktion einbezogen werden können. Andererseits heben aktuelle Technologieentwicklungen die Restriktion auf flache Oberflächen auf, so dass Touchscreens künftig ertastbare Strukturen aufweisen können. Diese Dissertation beschreibt die systematische Untersuchung großer und nicht-flacher interaktiver Oberflächen und analysiert ihr Potential für die Interaktion während der Fahrt. Dazu wurden für jede Charakteristik verschiedene Prototypen entwickelt und in Testumgebungen entsprechend ihres Reifegrads evaluiert. Auf diese Weise konnten subjektives Nutzerfeedback und objektive Daten erhoben, und die Effekte auf Fahr- und Blickverhalten sowie Nutzbarkeit untersucht werden. Diese Dissertation leistet den Beitrag einer Analyse der Entwicklung von interaktiven Oberflächen im Automobilbereich. Weiterhin werden die Aspekte Größe und Form untersucht, um mit ihrer Hilfe die Interaktion im Vergleich zu herkömmlichen Touchscreens zu verbessern. Die durchgeführten Studien belegen, dass große Flächen neue und verbesserte Bedienmöglichkeiten bieten können. Außerdem zeigt sich ein positiver Effekt auf die visuelle Ablenkung, wenn zusätzliches statisches, haptisches Feedback durch nicht-flache Oberflächen bereitgestellt wird. Zusammenfassend zeigen verschiedene, untereinander kombinierbare Interaktionskonzepte das Potential interaktiver Oberflächen für den automotiven Einsatz. Zudem können die Ergebnisse auch in anderen Bereichen Anwendung finden, in denen visuelle Aufmerksamkeit für andere Aufgaben benötigt wird

Optimizing Human Performance in Mobile Text Entry

Although text entry on mobile phones is abundant, research strives to achieve desktop typing performance "on the go". But how can researchers evaluate new and existing mobile text entry techniques? How can they ensure that evaluations are conducted in a consistent manner that facilitates comparison? What forms of input are possible on a mobile device? Do the audio and haptic feedback options with most touchscreen keyboards affect performance? What influences users' preference for one feedback or another? Can rearranging the characters and keys of a keyboard improve performance? This dissertation answers these questions and more. The developed TEMA software allows researchers to evaluate mobile text entry methods in an easy, detailed, and consistent manner. Many in academia and industry have adopted it. TEMA was used to evaluate a typical QWERTY keyboard with multiple options for audio and haptic feedback. Though feedback did not have a significant effect on performance, a survey revealed that users' choice of feedback is influenced by social and technical factors. Another study using TEMA showed that novice users entered text faster using a tapping technique than with a gesture or handwriting technique. This motivated rearranging the keys and characters to create a new keyboard, MIME, that would provide better performance for expert users. Data on character frequency and key selection times were gathered and used to design MIME. A longitudinal user study using TEMA revealed an entry speed of 17 wpm and a total error rate of 1.7% for MIME, compared to 23 wpm and 5.2% for QWERTY. Although MIME's entry speed did not surpass QWERTY's during the study, it is projected to do so after twelve hours of practice. MIME's error rate was consistently low and significantly lower than QWERTY's. In addition, participants found MIME more comfortable to use, with some reporting hand soreness after using QWERTY for extended periods

Designing for Cross-Device Interactions

Driven by technological advancements, we now own and operate an ever-growing number of digital devices, leading to an increased amount of digital data we produce, use, and maintain. However, while there is a substantial increase in computing power and availability of devices and data, many tasks we conduct with our devices are not well connected across multiple devices. We conduct our tasks sequentially instead of in parallel, while collaborative work across multiple devices is cumbersome to set up or simply not possible. To address these limitations, this thesis is concerned with cross-device computing. In particular it aims to conceptualise, prototype, and study interactions in cross-device computing. This thesis contributes to the field of Human-Computer Interaction (HCI)—and more specifically to the area of cross-device computing—in three ways: first, this work conceptualises previous work through a taxonomy of cross-device computing resulting in an in-depth understanding of the field, that identifies underexplored research areas, enabling the transfer of key insights into the design of interaction techniques. Second, three case studies were conducted that show how cross-device interactions can support curation work as well as augment users’ existing devices for individual and collaborative work. These case studies incorporate novel interaction techniques for supporting cross-device work. Third, through studying cross-device interactions and group collaboration, this thesis provides insights into how researchers can understand and evaluate multi- and cross-device interactions for individual and collaborative work. We provide a visualization and querying tool that facilitates interaction analysis of spatial measures and video recordings to facilitate such evaluations of cross-device work. Overall, the work in this thesis advances the field of cross-device computing with its taxonomy guiding research directions, novel interaction techniques and case studies demonstrating cross-device interactions for curation, and insights into and tools for effective evaluation of cross-device systems

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

Cruiser and PhoTable: Exploring Tabletop User Interface Software for Digital Photograph Sharing and Story Capture

Digital photography has not only changed the nature of photography and the photographic process, but also the manner in which we share photographs and tell stories about them. Some traditional methods, such as the family photo album or passing around piles of recently developed snapshots, are lost to us without requiring the digital photos to be printed. The current, purely digital, methods of sharing do not provide the same experience as printed photographs, and they do not provide effective face-to-face social interaction around photographs, as experienced during storytelling. Research has found that people are often dissatisfied with sharing photographs in digital form. The recent emergence of the tabletop interface as a viable multi-user direct-touch interactive large horizontal display has provided the hardware that has the potential to improve our collocated activities such as digital photograph sharing. However, while some software to communicate with various tabletop hardware technologies exists, software aspects of tabletop user interfaces are still at an early stage and require careful consideration in order to provide an effective, multi-user immersive interface that arbitrates the social interaction between users, without the necessary computer-human interaction interfering with the social dialogue. This thesis presents PhoTable, a social interface allowing people to effectively share, and tell stories about, recently taken, unsorted digital photographs around an interactive tabletop. In addition, the computer-arbitrated digital interaction allows PhoTable to capture the stories told, and associate them as audio metadata to the appropriate photographs. By leveraging the tabletop interface and providing a highly usable and natural interaction we can enable users to become immersed in their social interaction, telling stories about their photographs, and allow the computer interaction to occur as a side-effect of the social interaction. Correlating the computer interaction with the corresponding audio allows PhoTable to annotate an automatically created digital photo album with audible stories, which may then be archived. These stories remain useful for future sharing -- both collocated sharing and remote (e.g. via the Internet) -- and also provide a personal memento both of the event depicted in the photograph (e.g. as a reminder) and of the enjoyable photo sharing experience at the tabletop. To provide the necessary software to realise an interface such as PhoTable, this thesis explored the development of Cruiser: an efficient, extensible and reusable software framework for developing tabletop applications. Cruiser contributes a set of programming libraries and the necessary application framework to facilitate the rapid and highly flexible development of new tabletop applications. It uses a plugin architecture that encourages code reuse, stability and easy experimentation, and leverages the dedicated computer graphics hardware and multi-core processors of modern consumer-level systems to provide a responsive and immersive interactive tabletop user interface that is agnostic to the tabletop hardware and operating platform, using efficient, native cross-platform code. Cruiser's flexibility has allowed a variety of novel interactive tabletop applications to be explored by other researchers using the framework, in addition to PhoTable. To evaluate Cruiser and PhoTable, this thesis follows recommended practices for systems evaluation. The design rationale is framed within the above scenario and vision which we explore further, and the resulting design is critically analysed based on user studies, heuristic evaluation and a reflection on how it evolved over time. The effectiveness of Cruiser was evaluated in terms of its ability to realise PhoTable, use of it by others to explore many new tabletop applications, and an analysis of performance and resource usage. Usability, learnability and effectiveness of PhoTable was assessed on three levels: careful usability evaluations of elements of the interface; informal observations of usability when Cruiser was available to the public in several exhibitions and demonstrations; and a final evaluation of PhoTable in use for storytelling, where this had the side effect of creating a digital photo album, consisting of the photographs users interacted with on the table and associated audio annotations which PhoTable automatically extracted from the interaction. We conclude that our approach to design has resulted in an effective framework for creating new tabletop interfaces. The parallel goal of exploring the potential for tabletop interaction as a new way to share digital photographs was realised in PhoTable. It is able to support the envisaged goal of an effective interface for telling stories about one's photos. As a serendipitous side-effect, PhoTable was effective in the automatic capture of the stories about individual photographs for future reminiscence and sharing. This work provides foundations for future work in creating new ways to interact at a tabletop and to the ways to capture personal stories around digital photographs for sharing and long-term preservation

The role of metaphor in user interface design

The thesis discusses the question of how unfamiliar computing systems, particularly those with graphical user interfaces, are learned and used. In particular, the approach of basing the design and behaviour of on-screen objects in the system's model world on a coherent theme and employing a metaphor is explored. The drawbacks, as well as the advantages, of this approach are reviewed and presented. The use of metaphors is also contrasted with other forms of users' mental models of interactive systems, and the need to provide a system image from which useful mental models can be developed is presented. Metaphors are placed in the context of users' understanding of interactive systems and novel application is made of the Qualitative Process Theory (QPT) qualitative reasoning model to reason about the behaviour of on-screen objects, the underlying system functionality, and the relationship between the two. This analysis supports reevaluation of the domains between which user interface metaphors are said to form mappings. A novel user interface design, entitled Medusa, that adopts guidelines for the design of metaphor-based systems, and for helping the user develop successful mental models, based on the QPT analysis and an empirical study of a popular metaphor-based system, is described. The first Medusa design is critiqued using well-founded usability inspection method. Employing the Lakoff/Johnson theory, a revised version of the Medusa user interface is described that derives its application semantics and dialogue structures from the entailments of the knowledge structures that ground understanding of the interface metaphor and that capture notions of embodiment in interaction with computing devices that QPT descriptions cannot. Design guidelines from influential existing work, and new methods of reasoning about metaphor-based designs, are presented with a number of novel graphical user interface designs intended to overcome the failings of existing systems and design approaches

Cruiser and PhoTable: Exploring Tabletop User Interface Software for Digital Photograph Sharing and Story Capture

Digital photography has not only changed the nature of photography and the photographic process, but also the manner in which we share photographs and tell stories about them. Some traditional methods, such as the family photo album or passing around piles of recently developed snapshots, are lost to us without requiring the digital photos to be printed. The current, purely digital, methods of sharing do not provide the same experience as printed photographs, and they do not provide effective face-to-face social interaction around photographs, as experienced during storytelling. Research has found that people are often dissatisfied with sharing photographs in digital form. The recent emergence of the tabletop interface as a viable multi-user direct-touch interactive large horizontal display has provided the hardware that has the potential to improve our collocated activities such as digital photograph sharing. However, while some software to communicate with various tabletop hardware technologies exists, software aspects of tabletop user interfaces are still at an early stage and require careful consideration in order to provide an effective, multi-user immersive interface that arbitrates the social interaction between users, without the necessary computer-human interaction interfering with the social dialogue. This thesis presents PhoTable, a social interface allowing people to effectively share, and tell stories about, recently taken, unsorted digital photographs around an interactive tabletop. In addition, the computer-arbitrated digital interaction allows PhoTable to capture the stories told, and associate them as audio metadata to the appropriate photographs. By leveraging the tabletop interface and providing a highly usable and natural interaction we can enable users to become immersed in their social interaction, telling stories about their photographs, and allow the computer interaction to occur as a side-effect of the social interaction. Correlating the computer interaction with the corresponding audio allows PhoTable to annotate an automatically created digital photo album with audible stories, which may then be archived. These stories remain useful for future sharing -- both collocated sharing and remote (e.g. via the Internet) -- and also provide a personal memento both of the event depicted in the photograph (e.g. as a reminder) and of the enjoyable photo sharing experience at the tabletop. To provide the necessary software to realise an interface such as PhoTable, this thesis explored the development of Cruiser: an efficient, extensible and reusable software framework for developing tabletop applications. Cruiser contributes a set of programming libraries and the necessary application framework to facilitate the rapid and highly flexible development of new tabletop applications. It uses a plugin architecture that encourages code reuse, stability and easy experimentation, and leverages the dedicated computer graphics hardware and multi-core processors of modern consumer-level systems to provide a responsive and immersive interactive tabletop user interface that is agnostic to the tabletop hardware and operating platform, using efficient, native cross-platform code. Cruiser's flexibility has allowed a variety of novel interactive tabletop applications to be explored by other researchers using the framework, in addition to PhoTable. To evaluate Cruiser and PhoTable, this thesis follows recommended practices for systems evaluation. The design rationale is framed within the above scenario and vision which we explore further, and the resulting design is critically analysed based on user studies, heuristic evaluation and a reflection on how it evolved over time. The effectiveness of Cruiser was evaluated in terms of its ability to realise PhoTable, use of it by others to explore many new tabletop applications, and an analysis of performance and resource usage. Usability, learnability and effectiveness of PhoTable was assessed on three levels: careful usability evaluations of elements of the interface; informal observations of usability when Cruiser was available to the public in several exhibitions and demonstrations; and a final evaluation of PhoTable in use for storytelling, where this had the side effect of creating a digital photo album, consisting of the photographs users interacted with on the table and associated audio annotations which PhoTable automatically extracted from the interaction. We conclude that our approach to design has resulted in an effective framework for creating new tabletop interfaces. The parallel goal of exploring the potential for tabletop interaction as a new way to share digital photographs was realised in PhoTable. It is able to support the envisaged goal of an effective interface for telling stories about one's photos. As a serendipitous side-effect, PhoTable was effective in the automatic capture of the stories about individual photographs for future reminiscence and sharing. This work provides foundations for future work in creating new ways to interact at a tabletop and to the ways to capture personal stories around digital photographs for sharing and long-term preservation

The tool space

Visions of futuristic desktop computer work spaces have often incorporated large interactive surfaces that either integrate into or replace the prevailing desk setup with displays, keyboard and mouse. Such visions often connote the distinct characteristics of direct touch interaction, e.g. by transforming the desktop into a large touch screen that allows interacting with content using one’s bare hands. However, the role of interactive surfaces for desktop computing may not be restricted to enabling direct interaction. Especially for prolonged interaction times, the separation of visual focus and manual input has proven to be ergonomic and is usually supported by vertical monitors and separate – hence indirect – input devices placed on the horizontal desktop. If we want to maintain this ergonomically matured style of computing with the introduction of interactive desktop displays, the following question arises: How can and should this novel input and output modality affect prevailing interaction techniques. While touch input devices have been used for decades in desktop computing as track pads or graphic tablets, the dynamic rendering of content and increasing physical dimensions of novel interactive surfaces open up new design opportunities for direct, indirect and hybrid touch input techniques. Informed design decisions require a careful consideration of the relationship between input sensing, visual display and applied interaction styles. Previous work in the context of desktop computing has focused on understanding the dual-surface setup as a holistic unit that supports direct touch input and allows the seamless transfer of objects across horizontal and vertical surfaces. In contrast, this thesis assumes separate spaces for input (horizontal input space) and output (vertical display space) and contributes to the understanding of how interactive surfaces can enrich indirect input for complex tasks, such as 3D modeling or audio editing. The contribution of this thesis is threefold: First, we present a set of case studies on user interface design for dual-surface computer workspaces. These case studies cover several application areas such as gaming, music production and analysis or collaborative visual layout and comprise formative evaluations. On the one hand, these case studies highlight the conflict that arises when the direct touch interaction paradigm is applied to dual-surface workspaces. On the other hand, they indicate how the deliberate avoidance of established input devices (i.e. mouse and keyboard) leads to novel design ideas for indirect touch-based input. Second, we introduce our concept of the tool space as an interaction model for dual-surface workspaces, which is derived from a theoretical argument and the previous case studies. The tool space dynamically renders task-specific input areas that enable spatial command activation and increase input bandwidth through leveraging multi-touch and two-handed input. We further present evaluations of two concept implementations in the domains 3D modeling and audio editing which demonstrate the high degrees of control, precision and sense of directness that can be achieved with our tools. Third, we present experimental results that inform the design of the tool space input areas. In particular, we contribute a set of design recommendations regarding the understanding of two-handed indirect multi-touch input and the impact of input area form factors on spatial cognition and navigation performance.Zukunftsvisionen thematisieren zuweilen neuartige, auf großen interaktiven Oberflächen basierende Computerarbeitsplätze, wobei etablierte PC-Komponenten entweder ersetzt oder erweitert werden. Oft schwingt bei derartigen Konzepten die Idee von natürlicher oder direkter Toucheingabe mit, die es beispielsweise erlaubt mit den Fingern direkt auf virtuelle Objekte auf einem großen Touchscreen zuzugreifen. Die Eingabe auf interaktiven Oberflächen muss aber nicht auf direkte Interaktionstechniken beschränkt sein. Gerade bei längerer Benutzung ist aus ergonomischer Sicht eine Trennung von visuellem Fokus und manueller Eingabe von Vorteil, wie es zum Beispiel bei der Verwendung von Monitoren und den gängigen Eingabegeräten der Fall ist. Soll diese Art der Eingabe auch bei Computerarbeitsplätzen unterstützt werden, die auf interaktiven Oberflächen basieren, dann stellt sich folgende Frage: Wie wirken sich die neuen Ein- und Ausgabemodalitäten auf vorherrschende Interaktionstechniken aus? Toucheingabe kommt beim klassischen Desktop-Computing schon lange zur Anwendung: Im Gegensatz zu sogenannten Trackpads oder Grafiktabletts eröffnen neue interaktive Oberflächen durch ihre visuellen Darstellungsmöglichkeiten und ihre Größe neue Möglichkeiten für das Design von direkten, indirekten oder hybriden Eingabetechniken. Fundierte Designentscheidungen erfordern jedoch eine sorgfältige Auseinandersetzung mit Ein- und Ausgabetechnologien sowie adequaten Interaktionsstilen. Verwandte Forschungsarbeiten haben sich auf eine konzeptuelle Vereinheitlichung von Arbeitsbereichen konzentriert, die es beispielsweise erlaubt, digitale Objekte mit dem Finger zwischen horizontalen und vertikalen Arbeitsbereichen zu verschieben. Im Gegensatz dazu geht die vorliegende Arbeit von logisch und räumlich getrennten Bereichen aus: Die horizontale interaktive Oberfläche dient primär zur Eingabe, während die vertikale als Display fungiert. Insbesondere trägt diese Arbeit zu einem Verständnis bei, wie durch eine derartige Auffassung interaktiver Oberflächen komplexe Aufgaben, wie zum Beispiel 3D-Modellierung oder Audiobearbeitung auf neue und gewinnbringende Art und Weise unterstützt werden können. Der wissenschaftliche Beitrag der vorliegenden Arbeit lässt sich in drei Bereiche gliedern: Zunächst werden Fallstudien präsentiert, die anhand konkreter Anwendungen (z.B. Spiele, Musikproduktion, kollaboratives Layout) neuartige Nutzerschnittstellen für Computerarbeitsplätze explorieren und evaluieren, die horizontale und vertikale interaktive Oberflächen miteinander verbinden. Einerseits verdeutlichen diese Fallstudien verschiedene Konflikte, die bei der Anwendung von direkter Toucheingabe an solchen Computerarbeitsplätzen hervorgerufen werden. Andererseits zeigen sie auf, wie der bewusste Verzicht auf etablierte Eingabegeräte zu neuen Toucheingabe-Konzepten führen kann. In einem zweiten Schritt wird das Toolspace-Konzept als Interaktionsmodell für Computerarbeitsplätze vorgestellt, die auf einem Verbund aus horizontaler und vertikaler interaktiver Oberfläche bestehen. Dieses Modell ergibt sich aus den vorangegangenen Fallstudien und wird zusätzlich theoretisch motiviert. Der Toolspace stellt anwendungsspezifische und dynamische Eingabeflächen dar, die durch räumliche Aktivierung und die Unterstützung beidhändiger Multitouch-Eingabe die Eingabebandbreite erhöhen. Diese Idee wird anhand zweier Fallstudien illustriert und evaluiert, die zeigen, dass dadurch ein hohes Maß an Kontrolle und Genauigkeit erreicht sowie ein Gefühl von Direktheit vermittelt wird. Zuletzt werden Studienergebnisse vorgestellt, die Erkenntnisse zum Entwurf von Eingabeflächen im Tool Space liefern, insbesondere zu den Themen beidhändige indirekte Multitouch-Eingabe sowie zum Einfluss von Formfaktoren auf räumliche Kognition und Navigation

Bringing the Physical to the Digital

This dissertation describes an exploration of digital tabletop interaction styles, with the ultimate goal of informing the design of a new model for tabletop interaction. In the context of this thesis the term digital tabletop refers to an emerging class of devices that afford many novel ways of interaction with the digital. Allowing users to directly touch information presented on large, horizontal displays. Being a relatively young field, many developments are in flux; hardware and software change at a fast pace and many interesting alternative approaches are available at the same time. In our research we are especially interested in systems that are capable of sensing multiple contacts (e.g., fingers) and richer information such as the outline of whole hands or other physical objects. New sensor hardware enable new ways to interact with the digital. When embarking into the research for this thesis, the question which interaction styles could be appropriate for this new class of devices was a open question, with many equally promising answers. Many everyday activities rely on our hands ability to skillfully control and manipulate physical objects. We seek to open up different possibilities to exploit our manual dexterity and provide users with richer interaction possibilities. This could be achieved through the use of physical objects as input mediators or through virtual interfaces that behave in a more realistic fashion. In order to gain a better understanding of the underlying design space we choose an approach organized into two phases. First, two different prototypes, each representing a specific interaction style – namely gesture-based interaction and tangible interaction – have been implemented. The flexibility of use afforded by the interface and the level of physicality afforded by the interface elements are introduced as criteria for evaluation. Each approaches’ suitability to support the highly dynamic and often unstructured interactions typical for digital tabletops is analyzed based on these criteria. In a second stage the learnings from these initial explorations are applied to inform the design of a novel model for digital tabletop interaction. This model is based on the combination of rich multi-touch sensing and a three dimensional environment enriched by a gaming physics simulation. The proposed approach enables users to interact with the virtual through richer quantities such as collision and friction. Enabling a variety of fine-grained interactions using multiple fingers, whole hands and physical objects. Our model makes digital tabletop interaction even more “natural”. However, because the interaction – the sensed input and the displayed output – is still bound to the surface, there is a fundamental limitation in manipulating objects using the third dimension. To address this issue, we present a technique that allows users to – conceptually – pick objects off the surface and control their position in 3D. Our goal has been to define a technique that completes our model for on-surface interaction and allows for “as-direct-as possible” interactions. We also present two hardware prototypes capable of sensing the users’ interactions beyond the table’s surface. Finally, we present visual feedback mechanisms to give the users the sense that they are actually lifting the objects off the surface. This thesis contributes on various levels. We present several novel prototypes that we built and evaluated. We use these prototypes to systematically explore the design space of digital tabletop interaction. The flexibility of use afforded by the interaction style is introduced as criterion alongside the user interface elements’ physicality. Each approaches’ suitability to support the highly dynamic and often unstructured interactions typical for digital tabletops are analyzed. We present a new model for tabletop interaction that increases the fidelity of interaction possible in such settings. Finally, we extend this model so to enable as direct as possible interactions with 3D data, interacting from above the table’s surface