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On asymptotics of least squares estimators in single-node regression trees
No full textThis thesis considers a regression model for two real-valued random variables. Instead of estimating the nonparametric regression function itself, we assume that, according to the quadratic mean, there exists a best approximation among all step functions with a fixed number of jumps, the regression tree.
To estimate the regression tree, we use least squares estimators for its parameters. The main objective is to formulate limit theorems. For this purpose, we analyse the convergence behaviour of the estimators in different cases and observe the corresponding rates, which range from the cube root to one. The rate and limit depends on how the regression function behaves in the neighbourhood of the jumps in the regression tree.
For the results, however, we use and generalise a well-known arginf-CMT for the Skorokhod space and introduce an invariance principle, both of which can also be used in other contexts.:1. Introduction
2. Regression model and least squares estimator
3. Random variables in the multivariate Skorokhod space
4. Change-point problem
5. Split-point problem
6. Simultaneous analysis of change- and split-points
7. Consistency of the estimator
8. An estimator for the optimal number of jumps
A Appendi
Experimental and Numerical Investigation of Compressed Wood and Adhesive-Free Dowel Laminated Timber for Structural Components
No full textDiese Dissertation untersucht die Machbarkeit der Verwendung von verdichtetem Holz und Brettstapelholz in strukturellen Bauteilen, insbesondere in Decken- und Wandelementen. Die Forschung ist Teil des Projekts Towards Adhesive-Free Timber Buildings, das darauf abzielt, die Umweltbelastung im Bauwesen zu reduzieren, indem Alternativen zu herkömmlichen holzwerkstoffbasierten Bauprodukten und metallischen Verbindungsmitteln entwickelt werden. Während holzbasierte Bauprodukte wie Brettsperrholz und Brettschichtholz zunehmend an Bedeutung gewinnen, stellt ihre Abhängigkeit von Klebstoffen und metallischen Verbindungsmitteln eine Herausforderung für Nachhaltigkeit, Recyclingfähigkeit und das End-of-Life-Management dar. Diese Studie untersucht verdichtetes Holz und Brettstapelholz als nachhaltige Alternativen, die den Einsatz chemischer Verbindungen minimieren und gleichzeitig die strukturelle Integrität erhalten. Ein umfassendes experimentelles Programm wurde durchgeführt, das über siebenhundertzwanzig Tests zur Bewertung der mechanischen Eigenschaften von verdichtetem Holz umfasste, darunter Druck-, Zug-, Biege-, Einpress-, Fließmoment-, Scher- und Schlagfestigkeitstests. Die Ergebnisse zeigen, dass verdichtetes Holz im Vergleich zu unverdichtetem Holz deutlich verbesserte mechanische Eigenschaften aufweist, insbesondere eine höhere Elastizitätsmodul und Druckfestigkeit. Darüber hinaus wurden Brettstapelelemente mit verdichteten Holzdübeln in Decken und Wänden untersucht, wobei festgestellt wurde, dass sie eine vergleichbare Tragfähigkeit zu Elementen mit unverdichteten Hartholzdübeln aufweisen. Um das Verhalten dieser Systeme besser zu verstehen, wurden numerische Modelle mit der Finite-Elemente-Software entwickelt, die das strukturelle Verhalten von verdichtetem Holz und Brettstapelholz unter verschiedenen Lastbedingungen simulieren. Diese Modelle wurden anhand experimenteller Ergebnisse validiert, um Einblicke in Lastverteilung, Versagensmechanismen und Optimierungspotenziale der Bauteile zu gewinnen.
Durch die Charakterisierung von verdichtetem Holz und die Bewertung von Brettstapelholz als strukturelles System unterstützt diese Forschung die Etablierung und Weiterentwicklung von verdichtetem Holz in ingenieurtechnischen Holzbauanwendungen. Während verdichtetes Holz die Materialeigenschaften signifikant verbessert, erfordert seine Integration in großformatige Bauteile weitere Optimierung, um die Tragfähigkeit, Steifigkeit und langfristige Leistungsfähigkeit im Bauwesen zu maximieren.:Table of Contents
FOREWORD I
ABSTRACT II
TABLE OF CONTENTS III
LIST OF ABBREVIATIONS VI
LIST OF SYMBOLS VII
TABLE OF FIGURES X
LIST OF TABLES XVI
1 INTRODUCTION 1
1.1 Background and Motivation 2
1.2 AFTB Project 5
1.3 Research Objectives and Methodology 8
1.4 Scope of the Dissertation 11
2 WOOD: PROPERTIES, EVOLUTION AND ECOLOGY 13
2.1 Wood 15
2.1.1 Wood Structure 15
2.1.2 Mechanical Properties of Wood 22
2.2 Ecological Investigation in Timber Construction 27
2.2.1 Environmental Impacts of Wood and Wood-based Materials 27
2.2.2 Case Study: The Forte Living Building 30
2.2.3 Comparative Life Cycle Assessment between CLT and DLT 32
3 COMPRESSED WOOD (CW) 41
3.1 Literature Review 43
3.1.1 Direction of Compression 44
3.1.2 Press Systems and Hydrological Conditions 45
3.1.3 Shape Memory and Springback 46
3.2 Material Characterization Tests 47
3.2.1 Materials and Methods 47
3.2.2 Tests and Results 50
3.3 Mechanical Properties of CW 65
3.3.1 Dependence of Strength on Density 68
3.4 Conclusion 70
4 CONSTRUCTION ELEMENTS 71
4.1 Background of Design Approaches 73
4.1.1 Hardwood Dowels as Mechanical Fasteners 73
4.1.2 Current Design Practice of DLT as a Slab Element 80
4.1.3 Current Design Practice of DLT as a Wall Element 81
4.2 Experiments (Construction Element Tests) 83
4.2.1 Push-out Shear Tests 83
4.2.2 Slab Tests 86
4.2.3 Wall Tests 110
5 NUMERICAL MODELING 129
5.1 Simulations 131
5.1.1 Simulation Process in ABAQUS 131
5.1.2 Hygro-Thermal-Mechanical Model of Wood (FEAP) 133
5.1.3 UMAT Subroutine (LIST) 134
5.2 Material Characterization Simulations 136
5.3 Construction Element Simulations 150
5.3.1 Slab Simulations 150
5.3.2 Wall Simulations 157
6 SUMMARY AND OUTLOOK 161
7 REFERENCES 167
8 APPENDIX 177
8.1 Manufacturing of Compressed Woods 178
8.1.1 Manufacturing Process of CW in Laboratory 178
8.1.2 Effects of Density on Compression Ratio in CW in Setting A 181
8.2 Additional Data for Ecological Investigation of CLT and DLT 185
8.3 Additional Data and Methods of Material Characterization Tests 189
8.3.1 Compression Tests 189
8.3.2 Tensile Tests 190
8.3.3 Bending Tests 191
8.3.4 Embedment Tests 193
8.3.5 Yield Moment Tests 194
8.3.6 Push-out Shear Tests 195
8.3.7 Charpy Impact Tests 197
8.3.8 Dynamic Drop Tests 200
8.4 Swelling Test on CW 202
8.5 Manufacturing EWPs - Suttner Company 206
8.6 Design of Engineered Wood Products 208
8.6.1 Design of Slab 208
8.6.2 Design of Wall 223
8.7 Calculation Models 229
8.7.1 Calculations Model for Slab 229
8.7.2 Calculation Model for Wall 241
8.8 Wall Tests (Data) 246
8.8.1 Vertical Wall Tests (Results) 246
8.8.2 Horizontal Wall Tests (Results) 247
8.9 Existing Dowel Laminated Timber Technologies 251
8.10 Static Calculations (Example of Dimensioning) 253
8.11 Background on Mathematical Model 258
8.11.1 Elastic Behavior 258
8.11.2 Plastic Behavior 258
8.11.3 Failure Criterion 261
8.12 Simulation Methods and Modeling Parameters in ABAQUS 265
8.12.1 Material Properties 265
8.12.2 Analysis Steps 265
8.12.3 Damping Factor 266
8.12.4 Equation Solver 267
8.12.5 Interaction 269
8.12.6 Setting Contact Properties 270
8.12.7 Loads 273
8.12.8 Mesh 274
8.12.9 Job 277
8.13 Simulation Additional Results 278
ATTACHMENT 287This dissertation explores the feasibility of using compressed wood (CW) and dowel laminated timber (DLT) in structural components, specifically focusing on slabs and walls. The research is part of the Towards Adhesive-Free Timber Buildings (AFTB) project, aimed at reducing the environmental impact of construction by developing alterna-tives to traditional engineered wood products (EWPs) and metallic fasteners. While EWPs like cross-laminated timber (CLT) and glulam have gained popularity, their reliance on adhesives and metal fasteners raises concerns regarding sustainability, recyclability and end-of-life processing. This study investigates CW and DLT as sustainable solutions that reduce chemical dependency while maintaining structural integrity.
A comprehensive experimental program was conducted, comprising over 720 tests to evaluate the mechanical properties of CW, including compression, tension, bending, embedment, yield moment, shear and impact strengths. The results indicate that CW exhibits superior mechanical properties compared to uncompressed wood, with signifi-cantly higher modulus of elasticity and compression strength. The research further assesses DLT elements incorporating CW dowels in slabs and walls, revealing that they maintain comparable load-bearing capacity to those assembled with uncompressed hardwood dowels.
To deepen the understanding of these systems, numerical models were developed using ABAQUS, simulating the structural behavior of CW and DLT under different loading conditions. These models were validated against experimental results to provide insight into the load distribution, failure mechanisms and optimization potential of CW and DLT components.
By characterizing CW and evaluating DLT as a structural system, this research supports the adoption and further development of CW in engineered timber applications. While CW significantly improves material properties, its structural performance in full-scale elements requires further refinement to optimize load-bearing capacity and stiffness in construction.:Table of Contents
FOREWORD I
ABSTRACT II
TABLE OF CONTENTS III
LIST OF ABBREVIATIONS VI
LIST OF SYMBOLS VII
TABLE OF FIGURES X
LIST OF TABLES XVI
1 INTRODUCTION 1
1.1 Background and Motivation 2
1.2 AFTB Project 5
1.3 Research Objectives and Methodology 8
1.4 Scope of the Dissertation 11
2 WOOD: PROPERTIES, EVOLUTION AND ECOLOGY 13
2.1 Wood 15
2.1.1 Wood Structure 15
2.1.2 Mechanical Properties of Wood 22
2.2 Ecological Investigation in Timber Construction 27
2.2.1 Environmental Impacts of Wood and Wood-based Materials 27
2.2.2 Case Study: The Forte Living Building 30
2.2.3 Comparative Life Cycle Assessment between CLT and DLT 32
3 COMPRESSED WOOD (CW) 41
3.1 Literature Review 43
3.1.1 Direction of Compression 44
3.1.2 Press Systems and Hydrological Conditions 45
3.1.3 Shape Memory and Springback 46
3.2 Material Characterization Tests 47
3.2.1 Materials and Methods 47
3.2.2 Tests and Results 50
3.3 Mechanical Properties of CW 65
3.3.1 Dependence of Strength on Density 68
3.4 Conclusion 70
4 CONSTRUCTION ELEMENTS 71
4.1 Background of Design Approaches 73
4.1.1 Hardwood Dowels as Mechanical Fasteners 73
4.1.2 Current Design Practice of DLT as a Slab Element 80
4.1.3 Current Design Practice of DLT as a Wall Element 81
4.2 Experiments (Construction Element Tests) 83
4.2.1 Push-out Shear Tests 83
4.2.2 Slab Tests 86
4.2.3 Wall Tests 110
5 NUMERICAL MODELING 129
5.1 Simulations 131
5.1.1 Simulation Process in ABAQUS 131
5.1.2 Hygro-Thermal-Mechanical Model of Wood (FEAP) 133
5.1.3 UMAT Subroutine (LIST) 134
5.2 Material Characterization Simulations 136
5.3 Construction Element Simulations 150
5.3.1 Slab Simulations 150
5.3.2 Wall Simulations 157
6 SUMMARY AND OUTLOOK 161
7 REFERENCES 167
8 APPENDIX 177
8.1 Manufacturing of Compressed Woods 178
8.1.1 Manufacturing Process of CW in Laboratory 178
8.1.2 Effects of Density on Compression Ratio in CW in Setting A 181
8.2 Additional Data for Ecological Investigation of CLT and DLT 185
8.3 Additional Data and Methods of Material Characterization Tests 189
8.3.1 Compression Tests 189
8.3.2 Tensile Tests 190
8.3.3 Bending Tests 191
8.3.4 Embedment Tests 193
8.3.5 Yield Moment Tests 194
8.3.6 Push-out Shear Tests 195
8.3.7 Charpy Impact Tests 197
8.3.8 Dynamic Drop Tests 200
8.4 Swelling Test on CW 202
8.5 Manufacturing EWPs - Suttner Company 206
8.6 Design of Engineered Wood Products 208
8.6.1 Design of Slab 208
8.6.2 Design of Wall 223
8.7 Calculation Models 229
8.7.1 Calculations Model for Slab 229
8.7.2 Calculation Model for Wall 241
8.8 Wall Tests (Data) 246
8.8.1 Vertical Wall Tests (Results) 246
8.8.2 Horizontal Wall Tests (Results) 247
8.9 Existing Dowel Laminated Timber Technologies 251
8.10 Static Calculations (Example of Dimensioning) 253
8.11 Background on Mathematical Model 258
8.11.1 Elastic Behavior 258
8.11.2 Plastic Behavior 258
8.11.3 Failure Criterion 261
8.12 Simulation Methods and Modeling Parameters in ABAQUS 265
8.12.1 Material Properties 265
8.12.2 Analysis Steps 265
8.12.3 Damping Factor 266
8.12.4 Equation Solver 267
8.12.5 Interaction 269
8.12.6 Setting Contact Properties 270
8.12.7 Loads 273
8.12.8 Mesh 274
8.12.9 Job 277
8.13 Simulation Additional Results 278
ATTACHMENT 28
Oxohydroxo-Tellurates(VI) K2[TeO2(OH)4] and K2[Fe2TeO6(OH)2] ⋅ 2H2O from Alkaline Hydroflux
No full textThe ultra-alkaline conditions of a hydroflux offer the possibility of redox chemistry far from the electrochemical standard potentials. We explored the possibilities of synthesizing tellurium(VI) compounds, using both tellurium(VI) and tellurium(IV) as starting materials. Colorless, block-shaped crystals of the oxohydroxotellurate(VI) K2[TeO2(OH)4] were synthesized from (NH4)2TeO4 in a KOH hydroflux at 200 °C. In the triclinic crystal structure, [TeO2(OH)4]2− octahedra are connected via hydrogen bonds to form layers, which are separated from each other by potassium cations. Yellow-colored platelets of the ferrate(III) tellurate(VI) K2[Fe2TeO6(OH)2] ⋅ 2H2O were obtained by oxidation of TeO2 with H2O2 followed by reaction with Fe(NO3)3 ⋅ 9H2O in a KOH hydroflux. In the monoclinic crystal structure, strongly corrugated anionic layers urn:x-wiley:00442313:media:zaac202300170:zaac202300170-math-0001 Fe2TeO6(OH)2]2− are covered with water molecules and separated from each other by potassium cations. The octahedrally coordinated iron(III) atoms form a distorted honeycomb network, in which they are antiferromagnetically coupled at room temperature and in external fields up to at least 7 T
Pilonidal sinus disease carcinoma: survival and recurrence analysis
No full textBackground:
The study aims to determine the survival and recurrence rates of pilonidal sinus disease (PSD) carcinoma.
Methods:
The data were collected retrospectively by searching the worldwide literature for all reports of carcinoma developing on the background of PSD. The results were presented using Kaplan–Meier curves.
Results:
Between 1900 and 2022, 140 cases of PSD carcinoma were published in 103 papers, with follow-up data available in 111 cases. Squamous cell carcinoma constituted 94.6% of the cases (n = 105). The disease-specific survival rate was 61.7% for 3 years, 59.8% for 5 years, and 53.2% for 10 years. There was a significant survival difference between stages: 80.0% in stages I and II, 70.8% in stage III, and 47.8% in stage IV (p = 0.01). The 5-year survival in G1-tumors was better than G2 and G3-tumors at 70.5% and 32.0%, respectively (p = 0.002). Recurrence occurred in 46.6% of the patients. The time-to-recurrence in patients treated with curative intention averaged 15.1 months (1–132 months). Local, regional, and distant recurrence was observed in 75.6%, 33.3%, and 28.9% of the recurrent tumors, respectively.
Conclusions:
Pilonidal sinus carcinoma has a worse prognosis than primary cutaneous squamous cell carcinoma. Poor prognostic factors include advanced-stage disease and poor differentiation
Leselust 2014: Chemnitzer Literaturtage 01. - 29. April 2014: Carmen-Maja Antoni, Jörg Armbruster, Stefan Bollmann, Horst Evers,, Jörg Gudzuhn, Ulrich Kutschera, Tanja Langer, Irina Liebmann, Sabine Rennefanz, Peter Wawerzinek
No full textIm Monat April sind alle Literatur- und Bücherfreunde zur fünften Veranstaltungsreihe der Chemnitzer Literaturtage „LESELUST“ ins Kulturzentrum „Das TIETZ“ eingeladen. Zeitgenössische Autoren und deutsche Schauspieler entführen
die Besucher bei Lesungen sowie szenischen Darstellungen in die Welt der Poesie, Romane und Gegenwartsgeschichten. Seit 2006 macht das Literaturfestival „LESELUST“ das Lesen zum Erlebnis. Namhafte Vorleser, wie der leider viel zu früh verstorbene Schauspieler Ulrich Mühe, Christoph Hein, der Träger des Internationalen Stefan-Heym-Preises 2013, die Szene-Moderatorin Sarah Kuttner und der Liedermacher Wolf Biermann schmücken die Gästeliste der Veranstaltung. LESELUST - ein Projekt des Kommunalen Eigenbetriebes der Stadt Chemnitz Das TIETZ gefördert durch die Kulturstiftung des Freistaates Sachsen
Augmented Displays - Combining Interactive Displays with Head-Mounted Augmented Reality
No full textDiese Arbeit stellt Augmented Displays vor, eine neue Klasse von Hybrid User Interfaces (HUIs), welche interaktive Oberflächen mit kopfgebundenen Augmented Reality Displays (AR HMDs) kombiniert. Beide Geräte sind ein einzelnes, nahtloses System integriert, in welchem sie ihre individuelles Potential entfalten können. Interaktive Oberflächen sind mittlerweile im Alltag allgegenwärtig. Durch ihre direkte Touch-Eingabe bieten sie einen niederschwelligen Zugang zu digitalen Inhalten und verdrängen zunehmend Desktop Computer. Obwohl diese Displays eine hohe Auflösung bieten, ist ihre Ausgabe lediglich zweidimensional. Gleichzeitig erfahren AR und VR Geräte eine ebenfalls immer größere Verbreitung. Im Gegensatz zu konventionellen Displays erlauben sie die Anzeige dreidimensionaler Inhalte mit einer hohen Immersion und bieten einen nahezu unbegrenzten Anzeigeraum. Aktuell haben sie noch Probleme mit Inhalten von hohem Detailgrad und der Interaktion mit den virtuellen Inhalten. Durch die Kombination beider Geräte können diese ihre individuellen Schwächen kompensieren und auf ihre Stärken aufbauen. Diesen Ansatz bezeichnet man als Hybrid User Interfaces. Im Rahmen dieser Arbeit wird eine Unterklasse von HUIs vorgestellt, welche als Augmented Displays bezeichnet wird. Insbesondere umfasst dies die Untersuchung der folgenden Forschungsfragen: (1) Was sind die Vorteile von der Kombination interaktiver Oberflächen mit kopfgebundener AR? (2) Welche visuellen Anteile der Benutzeroberfläche sollten entweder der interaktiven Oberfläche oder AR zugeordnet werden? (3) Wie können interaktive Oberflächen verwendet werden um räumlich verbundene AR Inhalte zu manipulieren? (4) Welche vielversprechenden Anwendungsbeispiele oder Anwendungsdomänen gibt es für die Kombination von Displays und AR?
Um diese Fragen zu beantworten wird ein umfassender Design Space vorgestellt, welcher die semantische und räumliche Verbindung zwischen der interaktiven Oberfläche und dem AR HMD beschreibt. Die Anforderungen an geeignete Geräte für Augmented Displays werden diskutiert und es wird untersucht, wie die Eingabemöglichkeiten der interaktiven Oberfläche für die Interaktion mit AR Inhalten verwendet werden können. Dieser reichhaltige Design Space wird durch eine Zahl von Anwendungsfällen untersucht, welche durch Veröffentlichungen in den Bereichen 3D Modellierung, Informationsvisualisierung auf großen Displays, Architektur, und medizinischer Visualisierungen repräsentiert werden. Außerdem wird ein System für die Evaluation von Augmented Displays Systemen vorgestellt. Abschließend werden mögliche Einschränkungen und Herausforderungen diskutiert, welche sich aus den Konzepten ergeben, sowie die mögliche Zukunft von Augmented Displays.:1 Introduction 1
1.1. Research Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Research Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Methodological Approach . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4. Outline and Contributions . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Background and Related Work 11
2.1. Background on Related Research Areas . . . . . . . . . . . . . . . . . 11
2.1.1. Mixed and Augmented Reality . . . . . . . . . . . . . . . . . . 11
2.1.2. Distributed User Interfaces . . . . . . . . . . . . . . . . . . . . 13
2.1.3. Multi-Display Environments . . . . . . . . . . . . . . . . . . . 13
2.1.4. Natural User Interfaces . . . . . . . . . . . . . . . . . . . . . . 14
2.1.5. Hybrid User Interfaces . . . . . . . . . . . . . . . . . . . . . . 16
2.2. Prior Work on Combining Displays and Mixed Reality . . . . . . . . . 17
2.2.1. Hybrid User Interfaces and Early Works . . . . . . . . . . . . 17
2.2.2. Extending Screen Space with AR . . . . . . . . . . . . . . . . 19
2.2.3. Degree of Integration . . . . . . . . . . . . . . . . . . . . . . . 20
2.2.4. Device Types and Use Cases . . . . . . . . . . . . . . . . . . . 22
3 Augmented Displays 25
3.1. Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.2. Supported Device Classes . . . . . . . . . . . . . . . . . . . . . . . . 27
3.3. Relationship Between Interactive Surface and AR HMD . . . . . . . . 29
3.3.1. Semantic Relationship . . . . . . . . . . . . . . . . . . . . . . 29
3.3.2. Spatial Proximity Levels . . . . . . . . . . . . . . . . . . . . . 30
3.3.3. Spatial Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.3.4. Boundaries and Filtering . . . . . . . . . . . . . . . . . . . . . 33
3.4. Interaction Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.5. Multi-User Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4 DesignAR: Immersive 3D-Modeling Combining Augmented Reality with
Interactive Displays 39
5 Personal Augmented Reality for Information Visualization on Large
Interactive Displays 55
6 Augmented Displays: Seamlessly Extending Interactive Surfaces with
Head-Mounted Augmented Reality 69
7 Exploring and Slicing Volumetric Medical Data in Augmented Reality
Using a Spatially-Aware Mobile Device 75
8 AvatAR: An Immersive Analysis Environment for Human Motion Data
Combining Interactive 3D Avatars and Trajectories 83
9 Discussion 101
9.1. Technical Considerations . . . . . . . . . . . . . . . . . . . . . . . . . 101
9.1.1. Head-Mounted Augmented Reality Displays . . . . . . . . . . 101
9.1.2. Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
9.1.3. Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
9.2. Evaluating Augmented Display Systems . . . . . . . . . . . . . . . . 104
9.3. Non-Rectangular Displays . . . . . . . . . . . . . . . . . . . . . . . . 106
9.4. Future Significance of Augmented Displays . . . . . . . . . . . . . . . 107
9.4.1. Possible Technological Development . . . . . . . . . . . . . . 108
9.4.2. Adapting Augmented Displays to Other Contexts . . . . . . . 110
10 Conclusion 111
10.1.Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
10.2.Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
10.3.Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
10.4.Final Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Bibliography 119
A Authorship Statements 131This thesis presents Augmented Displays, a new class of hybrid user interface (HUI) which combines interactive surfaces with head-mounted Augmented Reality displays (AR HMDs). Both devices are integrated into a single, seamless system to leverage their individual potential.
Interactive surfaces have become ubiquitous in our everyday lives. Thanks to their direct touch input, they offer intuitive access to digital content and are increasingly replacing desktop computers. Although these devices offer high resolution, their graphic output remains two-dimensional. At the same time, AR and VR devices are also becoming increasingly widespread. In contrast to conventional displays, they allow to display three-dimensional content with a high degree of immersion and offer an almost unlimited output space. However, they face problems in displaying high levels of detail and in interaction with content itself. Combining conventional displays with AR HMDs can compensate their individual weaknesses and build upon their corresponding strengths. This approach is known as hybrid user interfaces. This thesis presents a subclass of HUIs called Augmented Displays. In particular, the following research questions are investigated: (1) What are the benefits of combining interactive displays with head-mounted AR? (2) Which visual parts of the user interface should be mapped to either interactive surface and AR? (3) How can interactive surfaces be used to manipulate spatially related AR content? (4) What are promising use cases or application domains for the combination of displays with AR?
To answer those questions, a comprehensive design space is presented, which describes the semantic and spatial relationship between the interactive surface and AR HMD. The requirements for suitable devices for Augmented Displays are discussed as well as how the input capabilities of the interactive surface can be used to interact with AR content. This rich design space is then explored through a variety of use cases, represented by publications in the domains of 3D modeling, information visualization on large displays, architecture, and medical visualization. An additional publication presents a system for evaluating Augmented Displays and similar immersive systems. Finally, limitations and challenges regarding the concept and currently available devices are discussed, as is the possible future of Augmented Displays itself.:1 Introduction 1
1.1. Research Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Research Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Methodological Approach . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4. Outline and Contributions . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Background and Related Work 11
2.1. Background on Related Research Areas . . . . . . . . . . . . . . . . . 11
2.1.1. Mixed and Augmented Reality . . . . . . . . . . . . . . . . . . 11
2.1.2. Distributed User Interfaces . . . . . . . . . . . . . . . . . . . . 13
2.1.3. Multi-Display Environments . . . . . . . . . . . . . . . . . . . 13
2.1.4. Natural User Interfaces . . . . . . . . . . . . . . . . . . . . . . 14
2.1.5. Hybrid User Interfaces . . . . . . . . . . . . . . . . . . . . . . 16
2.2. Prior Work on Combining Displays and Mixed Reality . . . . . . . . . 17
2.2.1. Hybrid User Interfaces and Early Works . . . . . . . . . . . . 17
2.2.2. Extending Screen Space with AR . . . . . . . . . . . . . . . . 19
2.2.3. Degree of Integration . . . . . . . . . . . . . . . . . . . . . . . 20
2.2.4. Device Types and Use Cases . . . . . . . . . . . . . . . . . . . 22
3 Augmented Displays 25
3.1. Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.2. Supported Device Classes . . . . . . . . . . . . . . . . . . . . . . . . 27
3.3. Relationship Between Interactive Surface and AR HMD . . . . . . . . 29
3.3.1. Semantic Relationship . . . . . . . . . . . . . . . . . . . . . . 29
3.3.2. Spatial Proximity Levels . . . . . . . . . . . . . . . . . . . . . 30
3.3.3. Spatial Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.3.4. Boundaries and Filtering . . . . . . . . . . . . . . . . . . . . . 33
3.4. Interaction Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.5. Multi-User Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4 DesignAR: Immersive 3D-Modeling Combining Augmented Reality with
Interactive Displays 39
5 Personal Augmented Reality for Information Visualization on Large
Interactive Displays 55
6 Augmented Displays: Seamlessly Extending Interactive Surfaces with
Head-Mounted Augmented Reality 69
7 Exploring and Slicing Volumetric Medical Data in Augmented Reality
Using a Spatially-Aware Mobile Device 75
8 AvatAR: An Immersive Analysis Environment for Human Motion Data
Combining Interactive 3D Avatars and Trajectories 83
9 Discussion 101
9.1. Technical Considerations . . . . . . . . . . . . . . . . . . . . . . . . . 101
9.1.1. Head-Mounted Augmented Reality Displays . . . . . . . . . . 101
9.1.2. Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
9.1.3. Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
9.2. Evaluating Augmented Display Systems . . . . . . . . . . . . . . . . 104
9.3. Non-Rectangular Displays . . . . . . . . . . . . . . . . . . . . . . . . 106
9.4. Future Significance of Augmented Displays . . . . . . . . . . . . . . . 107
9.4.1. Possible Technological Development . . . . . . . . . . . . . . 108
9.4.2. Adapting Augmented Displays to Other Contexts . . . . . . . 110
10 Conclusion 111
10.1.Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
10.2.Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
10.3.Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
10.4.Final Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Bibliography 119
A Authorship Statements 13
Blockchain concept to combat drug counterfeiting by increasing supply chain visibility
No full textThis paper explores problems of pharmaceutical supply chains, such as drug counterfeiting, and the opportunities of using digital technologies to overcome them. It also evaluates the risks associated with the use of digital technologies. Expert interviews were conducted with pharmaceutical supply chain stakeholders in the first step. The data obtained was assessed through qualitative content analysis. In addition to the lack of transparency, strong individual interests of the supply chain actors and different implementation levels of digitisation were revealed. It is also noticeable that the industry is still paper-oriented. Nevertheless, the chosen experts are optimistic about the increased use of digital technologies. Combining blockchain with other technologies, such as IoT and AI, can improve efficiency, traceability, and trust in pharmaceutical supply chains. A digitalised supply chain concept is developed based on these technologies, enhancing transparency and information availability in the supply chain. In addition, communication and processes along the entire pharmaceutical supply chain are optimised
