Available Thesis Topics

Depending on your preference, theses may be written in English or German.

A Mobile Force Feedback Device and Path Planning Approach for Obstacle Avoidance
Master Thesis, Supervisors: Tim Dünte , Max Pfeiffer , Michael Rohs
Tim Dünte can not supervise any further theses until 01.10.2018.

Electrical muscle stimulation (EMS) can influence the walking direction of pedestrians. A previous master's thesis has developed an obstacle avoidance algorithm and mobile EMS-based prototype for steering pedestrians around obstacles. The previous thesis applied methods from robotics to pedestrian navigation. The system scans the area in front of the user, detects obstacles, plans motion paths around them, and adjusts the stimulation of the sartorius muscle accordingly. The task of this thesis is to provide an in-depth evaluation of this system with users, including different obstacle locations and a comparison to other output technologies. This thesis should use the existing implementation as a basis.

AR Search for bookshelves
Master Thesis, Supervisor: Maximilian Schrapel

Have you ever looked for a book in a library, but it wasn't in the right place? The visual search may take a long time, but it may not be successful. In this thesis you will use image processing on Smartphones to find book covers in bookshelves. Algorithms have to be invented, implemented and tested. Furthermore, a user study will compare your implementation to visual search. Knowledge in Android is recommended.

Demonstrator for Pen and Paper Interfaces
Bachelor/Master Thesis, Supervisor: Maximilian Schrapel

Even today, where mobile devices are used in a wide variety of situations, analog devices such as pens and paper are indispensable. We have shown that digital pens and normal paper are capable of capturing input for interaction techniques. In this thesis an interaction technique will be developed and evaluated by a demonstrator. Basic knowledge in Python programming is required. Feel free to contact me.

Measuring the world: Make electronic devices smart!
Bachelor/Master Thesis, Supervisor: Maximilian Schrapel

Nowadays, many devices are integrated into the Smart Home network. Even simple devices such as electric water boilers can be switched on and off automatically. However, these devices have very special characteristics in the current consumption that reflect the current state. So far such features are unexplored. This thesis will use a given prototype to develop a smart home application that classifies the current status of multiple devices and uses it for human-computer interaction.

My Steps, My Path: Automatic Surface Estimation for Walked Paths
Master Thesis, Supervisor: Maximilian Schrapel

The condition of surfaces is an important factor in many areas. Paths can become muddy or slippery, depending on the weather conditions. Until now, such conditions are not available or only by manual input in map data. This results in safety risks that have not yet been taken into account in navigation systems for pedestrians. For sports activities such as running, data on the condition of the trails are also important features when preparing for a competition. Surfaces can also contain important characteristics in indoor navigation to determine the exact location. In this work, data on surfaces are to be investigated and used for navigation on the basis of a measurement unit integrated in a shoe. The aim is to find out how many different surfaces can be classified in order to automatically enter additional map information based on the results. For this thesis basic knowledge in Android and python programming is required.

Assigned Thesis Topics

Active Navigation
Master Thesis, Student: Peter Brandes, Supervisor: Maximilian Schrapel

Future mobility will introduce more flexible use of different means of transportation. It is important to stay healthy especially when you can travel from door to door without walking long distances. This thesis will give you the possibility to investigate on how you can combine autonomous cars, walking and/or cycling with health recommendations in urban environments. Your task is to implement a navigation system for android under usage of smart watches, health and contextual data (e.g. Weather, Calendar,...). Knowledge in android programming is recommended, feel free to contact me.

Development of a User Interface for Designing Vibrotactile Patterns for a Head-Mounted Output Device
Bachelor Thesis, Student: Leonard Hansing, Supervisor: Oliver Beren Kaul

Current generation virtual reality (VR) and augmented reality (AR) head-mounted displays (HMDs) usually include no or only a single vibration motor for haptic feedback and do not use it for guidance. We developed a vibrotactile guidance and immersion display called “HapticHead”, a system utilizing 24 vibration motors distributed in three concentric ellipses around the head to give intuitive haptic guidance hints and to increase immersion for VR and AR applications. The purpose of this Bachelor's thesis will be an in-depth evaluation of the possibilities arising from this device by developing a vibrotactile pattern design application in Unity. This includes finding and cataloging promising vibrotactile patterns, disseminating them into parts and developing a visual interface to design such patterns in a convenient way.
Research questions
Which kind of interface is best used to design vibrotactile patterns for a 3D output interface?
What kind of features should the designer interface provide?
How well can users adapt to designing vibrotactile patterns by themselves?

Effects of the Phantom Sensation on 3D Tactile Guidance around the Head
Bachelor Thesis, Student: Kerem Can Demir, Supervisor: Oliver Beren Kaul

Current generation virtual reality (VR) and augmented reality (AR) head-mounted displays (HMDs) usually include no or only a single vibration motor for haptic feedback and do not use it for guidance. We developed a vibrotactile guidance and immersion display called “HapticHead”, a system utilizing 24 vibration motors distributed in three concentric ellipses around the head to give intuitive haptic guidance hints and to increase immersion for VR and AR applications [1]. The purpose of this thesis will be an in-depth evaluation of the possibilities arising from this device by taking an existing prototype for 3D guidance and evaluating whether the Phantom Sensation occurs on different head regions with the current configuration. Furthermore, the maximum possible distance for the Phantom Sensation to arise shall be evaluated on different sites around the head by reconstructing a prototype from related work (Kerdegari et al.). Lastly, this thesis should investigate whether the Phantom Sensation has an effect on guidance performance of HapticHead and how a possible positive effect can be tuned to further increase the guidance performance.
Research questions
On which head regions does the phantom effect occur and how wide can the actuator spacing be for different head regions?
How does the phantom effect influence guidance performance?
Even if the phantom effect does not occur due to a too wide actuator spacing, does interpolation between actuators increase guidance performance?

Extending and Testing the PostFix IDE
Bachelor Thesis, Student: Marcel Budoj, Supervisor: Michael Rohs

PostFix is a programming language and IDE for beginners. PostFix is a stack-based language. Its only data structure is the array. All objects are immutable. The language is inspired by stack-based languages such as PostScript and Forth, but also by Lisps such as Racket and NewLisp. An integrated development environment (IDE) has been designed in a prior Master’s Thesis. The IDE is currently being used in an introductory programming course. The aim of this Bachelor’s Thesis is to use the experience from the course to improve the IDE and to add novel features. In particular the following aspects should be addressed: Improvement of the interactive graphics capabilities of PostFix, improved error messages, a testing framework for PostFix and the IDE, and tail-call optimization.

Extraction of Immersive Tactile Effects from the Sound of Movies for a Head-Based Output Interface
Bachelor Thesis, Student: Jonas Fabiasik, Supervisor: Oliver Beren Kaul

Current generation virtual reality (VR) and augmented reality (AR) head-mounted displays (HMDs) usually include no or only a single vibration motor for haptic feedback and do not use it for guidance. We developed a vibrotactile guidance and immersion display called “HapticHead”, a system utilizing 24 vibration motors distributed in three concentric ellipses around the head to give intuitive haptic guidance hints and to increase immersion for VR and AR applications [1]. The purpose of this Bachelor/Master’s thesis will be an in-depth evaluation of the possibilities arising from this device by implementing a framework to automatically extract sound from movies and turning this extracted sound into tactile effects for HapticHead. Furthermore, a user study shall prove the viability of the concept and test whether users experience an increased feeling of immersion in movies by adding these tactile effects.
Research questions
How can stereo sound be turned into useful 3D tactile effects for the HapticHead interface?
How do 3D tactile effects around the head influence the feeling of immersion in a movie?
How viable is the HapticHead interface for generating immersive tactile effects in the context of movies? How could it be improved?

Implementation and Evaluation of a Silent Head-Mounted Tactile Interface
Master Thesis, Student: Jonas Bock, Supervisor: Oliver Beren Kaul

Current generation virtual reality (VR) and augmented reality (AR) head-mounted displays (HMDs) usually include no or only a single vibration motor for haptic feedback and do not use it for guidance. We developed a vibrotactile guidance and immersion display called “HapticHead”, a system utilizing 24 vibration motors distributed in three concentric ellipses around the head to give intuitive haptic guidance hints and to increase immersion for VR and AR applications. The purpose of this Master’s thesis will be to replace the standard vibration motors with sophisticated actuators (under NDA) which feature independent amplitude and frequency control and the ability to still provide a high amplitude at a frequency as low as 20 Hz. A user study is to be conducted on the question of how well users can perceive low-frequency vibration feedback on different sites around the head and which amplitude factors need to be applied on different sites around the head so that the vibration amplitude feels the same on all sites. The modified prototype shall then be compared to the old prototype in a second, comparison user study versus related work.
Research questions
How a circuit board is best designed and miniaturized to drive a total of 24 [NDA] engines, allowing a change in amplitude and frequency at a rate of at least 120 Hz?
How does the new prototype compare to the old one in terms of user acceptance and vibration noise around the head?
How is the user guidance from the studies in affected by using lower frequencies for the vibration which cancels out the audible vibration noise?
How well can users perceive vibration on different sites around the head and how low can the frequency be tuned so that the vibration is still perceived at an acceptable strength?

Spectrophone: A novel apporach for surface classification with smartphones
Master Thesis, Student: Philipp Etgeton, Supervisor: Maximilian Schrapel

"Is it genuine leather or imitation leather?" - You may have asked or heard this question before in a shopping mall. What if you could classify surfaces such as leather or any others with your smartphone? This thesis will give you the opportunity to discover a novel approach for surface classification with today's smartphone sensors. Experiences in Android and image processing is recommended.

Visualization Framework for Motion Sensors
Master Thesis, Student: Ferdinand Lange, Supervisor: Maximilian Schrapel

Motion sensors are widely used in human-computer interaction. Their precise measurement data provide information about the current position of the hardware. This is important, for instance, to prevent drones from falling or to determine the current position of a smartphone. Even in automotive navigation systems IMU’s are applied to provide accurate data about the vehicle's current speed. For testing such sensors in new techniques it is often important to visualize the data first. In this thesis a framework will be created which animates 3D models based on the filtered raw data of such sensors. Basic knowledge in C++ is required. Feel free to contact be for more details.

Completed Theses

2018
Position Detection of an Electrode Grid via EMG Raw Data
[Bachelor Thesis, Student: Patrick Sachmann, Supervisor: Tim Dünte ]

In the field of man-machine communication, the use of EMG and EMS is becoming increasingly popular. A special problem was the fast and correct calibration of such systems. In this paper an approach for position detection of an electrode field with EMG raw data is presented. The prototype developed here at the institute consists of 2 electrode wristbands containing 18 and 22 electrodes. In the course of this work, a method for position detection was evaluated and the software of the prototype was rewritten. Eight subjects took part in the study, which was carried out to evaluate the position recognition and the prototype. Each subject made 54 gestures while the prototype was positioned at 3 different positions, one third of the circumference of the forearm being moved to each other. With the data collected from the study, the position sensing procedure was tested. The average displacement was 9 electrodes for rotation by a third. A shift of 14 electrodes was assumed for the two-thirds rotation, but the mean was 7 electrodes. Finally, reasons for the high discrepancy are discussed and proposals are made which could lead to more positive results in a new investigation.



2017
Ambient Notifications for a Shape-Changing Display
[Bachelor Thesis, Student: Christian Althaus, Supervisor: Tim Dünte ]

This thesis is about a shape-changing display, which can display information through height adjustment and led lights. An existing system was used to control the shape-changing display. This system will be examined and then redesigned with the objective to make it simpler and more compact, so that a user can take it with home. The developed system should allow visualization of real-time information from web sources. Furthermore, it should display information in an unobtrusive manner.The displayed scenarios, for example the current or predicted temperature, can be configured in a graphical user interface. It can be specified, how the information will be displayed. This, among others, includes specification of the led colors or different visualization modes. Therefore, a concept for displaying quantitative values is developed. Different animations were implemented to provide better feed-back of the developed system and scenarios.



Application Scenarios for Smartwatch Interactions with Distance Sensors
[Bachelor Thesis, Student: Lars Hamann, Supervisor: Michael Rohs ]

Touch screen interaction on smartwatches is problematic because of the small size of the screen and the occlusion caused by the finger. An alternative approach is around-device interaction in which the interaction happens in the space around the smartwatch. An object, the user's finger, or the user's body is tracked to trigger actions on the smartwatch. The objective of this thesis is to develop application scenarios for around-device interaction with smartwatches. The tracking is realized with an existing prototype that has a small number of time-of-flight distance sensors, which are attached to the watchstrap.



Curved Treemaps
[Master Thesis, Student: Christian Brosy, Supervisor: Michael Rohs ]

A Treemap is a space-filling visualization that shows an overview of the relative sizes of a large number of items. There has been a lot of research on Treemaps since their invention in the early 1990s. A challenge still is to adequately show the different nesting levels of a hierarchical structure. Typical approaches use labeled frames and borders whose width decreases with nesting level. This thesis investigates the idea of curved treemaps, i.e., treemaps with slightly bent borders. The main question to explore is whether curved treemaps are effective in conveying the hierarchical structure of the data. One justification for investigating curved boundaries are the Gestalt laws, in particular the laws of continuity and good form: We perceive continuous smooth curves (without sharp directional changes) as belonging together. In curved treemaps continuous curves are meant to be subdivide data on the same level.



Deep learning for handwriting recognition based on multi sensor data from pens
[Master Thesis, Student: Max-Ludwig Stadler, Supervisor: Maximilian Schrapel ]

Remembering handwritten Notes like dates or shopping list is a challenging task in a digitalized world. People may forget their important handwritten notes when they need them. Digital writing can build a bridge between handwritten papers and digital informations. There are several approaches to digitalize handwritten letters. This work focuses on movement sensors combined with audio data collected from the pen and involves research questions like how can simple letters be classified with neural networks?



Design and Evaluation of a wearable Device for the visual Representation of physical Exertion in Sport Groups
[Bachelor Thesis, Student: Felix Trommer, Supervisor: Tim Dünte ]

In this work a portable prototype is developed, which visualizes the physical effort of the wearer for others. This wearable is evaluated with a view to its use in sports groups in which a trainer could better adapt the training to the individual participants by using the wearable. The pulse of the carrier is measured and visualized by an LED. To measure the pulse, two different algorithms for heart rate detection are presented and discussed, three different types of visualization are proposed. Those visualizations are an LED pulsating parallel to the heartbeat, a coloured representation with three levels and a combination of the above representations. In a user study, these representations are evaluated with six participants with regard to acceptance, correctness of displayed excertion and simplicity of interpretation. In addition, different locations are discussed where the wearable can be worn on the body during sport without restricting the user.



Design and Evaluation of various EMG Sensors for Electrode Grids
[Bachelor Thesis, Student: Hendrik Frei, Supervisor: Tim Dünte ]

This thesis focuses on the development of an EMG -sensor especially for use in electrode fields such as wristbands. Different variants of this sensor were evaluated in a technical study with commercial EMG -sensors for the application of the electrode field. Downtimes of these sensors were investigated in a serial measurement setup. Differences between different high-pass filters for eliminating a DC offset voltage could be worked out. It was proven that the downtime of the sensors is dependent on the previous resistance state of the signal electrodes.



Design of a Casual Interaction Method for Notifications using EMS and EMG
[Bachelor Thesis, Student: Gerrit Rode, Supervisor: Tim Dünte ]

This bachelor thesis examines the use of electrical muscle stimulation for notifications. The focus is on the quantity of recognizable notification patterns. For this purpose, an existing prototype for mobile application scenarios was enhanced and twelve different notification patterns were designed. An Android app was developed, which can serve as a basis for future mobile applications of the prototype. The app generates the notification patterns in conjunction with the Let-Your-Body-Move-Toolkit, a device for manipulating an electrical signal that is used for muscle stimulation.The designed notification patterns were evaluated in a user study with 15 participants. The patterns were evaluated with regard to their recognition rates, the decision times required for recognition and feedback from participants. The average pattern recognition rate is 69.58%. Of the twelve notification patterns three patterns performed especially well in all these points. These patterns achieved detection rates of over 93% with short decision times of less than ten seconds and positive feedback from study participants. The positive feedback from the participants indicates that the use of EMS notifications can be an alternative to the traditional notification methods of a smartphone - sound, vibration and LED.



Design, Implementation, and Analysis of an IDE for a Beginner's Programming Language
[Master Thesis, Student: Björn Fiedler, Supervisor: Michael Rohs ]

The goal of this thesis is to develop an IDE that supports beginning programmers in writing simple programs and in understanding fundamental programming concepts. There is evidence that good error messages, syntax highlighting, short editing cycles, immediate feedback, stepwise execution, visualization of the execution state, and last but not least simple language semantics are important aspects of an IDE that aims to support programmers in their initial steps. The IDE is used in conjunction with a simple programming language, provisionally called PostFix, which is based on PostScript and Forth and which provides explicit access to the runtime stack. The explicit stack simplifies parameter passing and return semantics. The language is well suited for visualizing the execution state at each point. The IDE should support incremental interactive development using read-eval-print loops (REPLs) as in LISP-like languages. Programmers should be able to step through the execution of a program and see the evolution of the program stack and the dictionary stack of variables. This thesis should take into account existing approaches from practice as well as principles from the programming language usability community, such as the Cognitive Dimensions Framework. As part of the thesis selected aspects of the developed IDE should be evaluated.



Electromyography-Based Acknowledgement of Haptic Notifications
[Bachelor Thesis, Student: Justin Schulte, Supervisor: Tim Dünte ]

In this thesis, three acknowledgment methods for haptic notifications are compared. To this end, a system has been developed that can be used to receive notifications by muscular stimulation and send acknowledgments by electromyography on the same muscle. The three methods differ by the property that the acknowledgment is spatially or temporally encoded by electromyography or as a comparison a Smartwatch application is used. In a study of 12 participants, these different acknowledgment methods were compared. For this purpose, the data were evaluated quantitatively for response time and error rate as well as qualitatively with regard to the user acceptance. As a result, the electromyography-based method Direction achieved the best performance with a very positive user rating and a detection rate of 96%.



EMG-Based Hand and Finger Gesture Recognition with a Multi Electrode Grid
[Master Thesis, Student: Christian Dirkes, Supervisor: Tim Dünte ]

This master thesis deals with the question whether a 2D-electrode field is necessary to recognize hand and finger gestures. One focus here is the acquisition of EMG raw data using an existing prototype, which consists of two wristbands with 18 and 22 electrodes. Furthermore, it is examined how many gestures can be recognized with the existing prototype.For this purpose, a user study was conducted with twelve participants who performed 46 different hand and finger gestures in one session. The data obtained from this were evaluated with different machine learning classification methods against each other, using different gesture sets from the literature, depending on the user as well as independently of the user. Detection rates of up to 57% were achieved in the user-dependent procedure and up to 13% in the user-independent procedure with 46 different gestures. Furthermore, the recognition rates obtained here are compared with similar works.



EMG-Based Hand Gesture Recognition with a Multi Electrode Grid
[Bachelor Thesis, Student: Josef Kriegel, Supervisor: Tim Dünte ]

This bachelor thesis covers the measurement of muscle activity in the forearm using electromyography, an electrode sleeve and the evaluation of the values arising from the measurement with a machine-learning algorithm to distinguish different hand gestures. The prototype was evaluated in an additional study in which 5 gestures were successfully detected. The maximum detection accuracy fluctuated around 55 % using a Support Vector Machine and between 80 and 100 % using a randomForest algorithm.



Implicit calibration of three dimensional eyetracking gaze points based on moving objects in virtual reality
[Bachelor Thesis, Student: Tim Cofala, Supervisor: Maximilian Schrapel ]

A serious problem with eye trackers is the so called calibration drift. After a while with your eye tracking VR headset the gaze point will contain an offset error. In this this thesis you will implement an technique which follows your eye movements to determine what youre looking at. With that information you will correct a given 3D gaze point. Thus you will evaluate the research question can we increase the accuracy of eyetrackers for virtual reality? and What objects can be used for VR smooth pursuit? Knowledge in Unity and python is recommended. For further informations feel free to contact me.



Improving VR Presence using Head-Based Vibrotactile Feedback and Hand Tracking
[Master Thesis, Student: Bastian Krefeld, Supervisor: Oliver Beren Kaul ]

The feeling of being in a virtual environment, so-called presence, is important for experiencing these environments. In this thesis, the improvement of presence through the use of vibration feedback around the head in combination with interaction through hands is explored. The feedback at the head is given through a hat with built-in vibration motors, the so-called HapticHead. Interactions with the virtual world are done through the HTC Vive and its handtrackers. Interactions between the virtual objects held in the hand and the virtual head are simulated and analyzed. To analyze the feeling of presence, questionnaires are used. Additionally, data that is collected while users interact with the system is evaluated in regards to improvements of the feeling of presence through vibration feedback.



Position Detection of an Electrode Grids on the Forearm via EMG
[Bachelor Thesis, Student: Malte Lucius, Supervisor: Tim Dünte ]

Haptic input and output methods are becoming more and more popular in HCI. These require a good calibration in order to make the best use of these methods possible. This work is devoted to the problem of calibration of electrode grids on the forearm. For this purpose, an approach for displacement detection is presented. A prototype consisting of two separate bracelets with 18 or 22 electrodes was used to capture data. In the course of this thesis the prototype was reproduced and revised from the point of view of mobility. The changes made are presented during the course of the work. Subsequently, a study was conducted with twelve participants. These had to perform 135 repetitive gestures under various constraints such as rotation of the prototype to investigate whether different gestures can be used for displacement detection. Furthermore, qualitative information on the prototype was collected and evaluated. An attempt was made to apply a simple displacement detection method to the data collected in the study. This procedure led to an unsatisfactory result. The reasons for the failure of the procedure are discussed, evaluated and approaches for further investigations derived.



Real-Time Navigation of Visually Impaired Users via a Self-Positioning Device and Vibrotactile Feedback
[Master Thesis, Student: Guido Gardlo, Supervisor: Oliver Beren Kaul ]

Currently blind people rely on a stick to navigate through their surroundings. This thesis proposes a solution that could replace that method in the future. It combines a Google Tango smartphone, which is capable of self localization and object detection with HapticHead, a vibrotactile head worn device that is built for intuitive three-dimensional guidance. Together these tools form a navigation system for the blind. Two experiments are conducted where the first one indicates that vibrotactile patterns, when learned, could be used to transport navigational information. The second experiment shows a 75% success rate in waypoint navigation without crashing into unknown obstacles and a complete success in finding the direction of unknown objects with a mean error of 7 degrees.



Spatial Patterns for a Head-Worn Vibrotactile Display
[Master Thesis, Student: Marc Mogalle, Supervisor: Oliver Beren Kaul ]

Haptic feedback can replace auditory or visual feedback in case the other senses are already engaged or may not be disturbed. The HapticHead is a 3D vibrotactile around the head display able to play back a variety of tactile effects and patterns. This thesis explores different use cases of such a display, like as a notification display or navigational aid. For this purpose three experiments were conducted. Firstly, the appeal and distinguishability of vibrotactile patterns around the head were evaluated. As a result, ten patterns with above average recognition rate and rating were found. In the follow-up experiment, these top ten patterns were compared against single vibration motor patterns found in related work in terms of type, priority and location. The goal was to determine their eligibility of transmitting different kinds of phone notifications. The patterns’ types were recognized correctly at over 90 %, while the patterns’ recognition rate for location was even higher than 98 %. In the the third and final experiment, blindfolded participants were successfully guided through an obstacle course by static and dynamic patterns.



Usage of eye tracking depth information for interaction with objects in virtual reality
[Bachelor Thesis, Student: Jannik Dahlke, Supervisor: Maximilian Schrapel ]

Eye trackers can be used for gaze prioritized graphics or games and other tasks in VR. By collecting deph information from pupil positions the possibilities of VR human computer interactions can be increased rapidly. For example think about multiple overlayed VR-desktops you can select with your eyes or a CT scan you can look though. Even deph interactions in VR games are possible. In this thesis you implement and evaluate an interactive VR user Interface with deph informations given by an VR eye tracker. Knowledge in Unity and python is recommended. For further informations feel free to contact me.



Using pen movement and audio data to verify signatures
[Bachelor Thesis, Student: Lukas Nagel, Supervisor: Maximilian Schrapel ]

Forging of a signature is a serious problem in everyday business. A lot of transactions like cash transfer have to trust signatures. Your task will be to implement an additional acoustic mechanism which can differentiate between fake and original signatures. This will lead to basic research questions: How to detect signatures on different surfaces? or the quality of the classification? A small user study will evaluate the system. Knowledge in C, C++ or Java and Python is recommended. For more details please contact me.



2016
A Self-Calibrating Wearable Electrode Grid for Controlling Hand Gestures via EMS
[Master Thesis, Student: Tim Dünte, Supervisor: Max Pfeiffer ]

In this thesis the development and use of a prototype is presented, which allows the generation of hand gestures via electrical muscle stimulation (EMS). The prototype consists of two parts: a stimulation and control unit and an electrode grid. The stimulation unit can be used to control up to 20 different muscles with freely selectable parameters. The electrode grid consists of two silicone bracelets with 22 and 18 encapsulated electrodes. The prototype was self-constructed. Therefore, relevant components of the hardware as well as the software are presented. Since the prototype is self-made, the safety of the prototype is also discussed. The aim of the development was to enable a fine-granular control of the muscles in the forearm. With this fine-granular control hand gestures can be produced as a combination of several individual movements. Before the user can use the prototype, it must be calibrated to the user. For this reason, different calibration approaches for the calibration of the prototype are presented and a self-calibration approach is developed, which does not require any sensors at hand. Finally, a conclusion is drawn on the work and further research is presented, which is made possible by the prototype or its components.



A Shape-Changing Display for Ambient Notifications
[Master Thesis, Student: Andre Lehnert, Supervisor: Max Pfeiffer ]

The objective of this work is to provide a development environment for the design of an ambient multi-purpose shape-changing display which is controllable via a RESTful Web Service. The shape-changing display provides visual and physical representation of digital information in a comprehensible manner. In order to explain this closer a description of theoretical basis of the perception and the psychology of perception is given, which is set in relation to the development of physical data visualizations and tangible user interfaces (TUI). The token-based interaction is considered in more detail as part of TUIs. The findings are included in a concept that is evaluated with paper prototypes. The development of the prototype is done in an iterative design process. The resulting increments are presented. The qualitative assessment and the identification of additional applications completed a design workshop.



An Ambient Multi-Scale Information Object
[Bachelor Thesis, Student: Sezer Dursun, Supervisor: Henning Pohl ]

Ambient devices provide glanceable information in the periphery. One example of such a device would be a sphere glowing red when a stock is falling and green when it is rising. Such objects can nicely blend into the background, yet can provide useful information for the knowledgeable user. However, such objects usually fall short once more detailed information is desired - instead of just red or green, a user might want to see the actual percentage change in stock price. In this thesis, you will build an ambient device that helps people catch their next bus or tram. It will subtly change color as a new connection is approaching. However, your object shall actually include more information as the user approaches it (which bus, how many minutes, ...). For this, we will embed a proximity sensor into the object. Building such an object is fairly straightforward. An equally important part of this project shall be the evaluation. You'll give your device to several users who will keep it in their homes or offices for at least a couple of weeks. We'll use diary methods and interviews to find out more on how users perceived such objects and how their interaction with them changed over time.



Analysis and Modeling of Interactive Devices
[Bachelor Thesis, Student: Daphne Schössow, Supervisor: Michael Rohs ]

The goal of this thesis is to develop a platform that allows to easily analyze the user interface of existing interactive devices and to represent them as a virtual model. The virtual model can then be used in an interactive Web page or as a standalone app, and be modified for user testing. The virtual model may also serve to compute certain usability characteristics, given device states and display contents. The platform is supposed to include an interactive tabletop and camera-based capturing system. You should be familiar with Java and ideally have some experience with human-computer interaction.



Casual Interaction with a Smartwatch
[Master Thesis, Student: Sven Röttering, Supervisor: Henning Pohl ]

We have an existing prototype for a bracelet that acts as a wearable smart-home lighting controller. We would like to build on this and extend the available interaction space. We would also like to transition the prototype to a smartwatch in order to further integrate the system.



Competitive Emoji Response Game
[Bachelor Thesis, Student: Marco Deneke, Supervisor: Henning Pohl ]

In this thesis your job would be to implement a fun game for either Android or the web where players compete against each other in a contest to pick the best emoji. We envision this to be in an Apples to Apples like format where players respond to animated gifs showing an emotion.



Compression Feedback for Notifications
[Master Thesis, Student: Hung Ngo Quang, Supervisor: Henning Pohl ]

While we have explored general parameters of compression feedback, this thesis is supposed to evaluate concrete performance of compression feedback for notifications in an actual working scenario. Thus, you will need to hook into the Android notification mechanism and map incoming notifications or derived state from several notifications to some form of compression output.



Conception and Implementation of a System for Obstacle Avoidance in Pedestrian Navigation with Electrical Muscle Stimulation
[Master Thesis, Student: Sven Lilge, Supervisors: Max Pfeiffer , Steffen Busch ]

This work focuses on the exploration of electrical muscle stimulation (EMS) applications in the context of navigation tasks for pedestrians and visually impaired persons. The combination of localization, environment perception and EMS allows to navigate the user without the usual high cognitive load. In order to achieve this goal, a navigation system which uses EMS to steer its users around obstacles in their surroundings is designed and implemented. The system makes particulary use of a color and depth imaging system to perceive the environment and localize the user in it. The functionality and reliability of the system is evaluated in a user study, planned and carried out within this research work. Considering the achieved results of the study it is discussed whether an EMS based navigation can be used in every day life.



Design of a Tool for Analyzing and Modeling Interactive Devices
[Bachelor Thesis, Student: André Kamrad, Supervisor: Michael Rohs ]

The goal of this bachelor thesis is to design and develop a program capable of constructing a Finite State Machine graph out of a recorded video. The idea was to simplify the process of analyzing and optimizing the usability of interactive devices, by providing a low-effort tool to construct a FSM for further simulations.



Evaluation of a Vibrotactile Guidance and Immersion Display on the Head
[Bachelor Thesis, Student: Kevin Meier, Supervisor: Oliver Beren Kaul ]

Current generation virtual reality (VR) and augmented reality (AR) head-mounted displays (HMDs) usually include no or only a single vibration motor for haptic feedback and do not use it for guidance. We developed a vibrotactile guidance and immersion display called “HapticHead”, a system utilizing 20 vibration motors distributed in three concentric ellipses around the head to give intuitive haptic guidance hints and to increase immersion for VR and AR applications. The purpose of this Bachelor’s thesis will be an in-depth evaluation of the possibilities arising from this device. This includes conducting a user study with multiple participants on a target-finding task and the implementation and evaluation of immersive VR scenes with haptic feedback.



Indoor Navigation with Smartwatches
[Master Thesis, Student: Linh Phan, Supervisor: Michael Rohs ]

ScrollingHome is an interesting concept of indoor navigation using a smartwatch: A navigation path is broken up into a 1D stripe, shown visually on a smartwatch, and the user scrolls the photo stream to move towards the target. The goal of this thesis is to replace manual scrolling by the use of the sensors of the smartwatch and the mobile phone of the user and to develop a framework that allows selecting targets in a larger building. The main university building should serve as a testbed for this goal. Questions concern the achievable reliability of an automatic approach using only the built-in sensors of the smartwatch and the mobile phone.



Rapid Serial Visual Presentation on the Go
[Bachelor Thesis, Student: Tim Rouven Hamp, Supervisor: Michael Rohs ]

Smartwatches have extremely small display areas. Information presentation and selection could potentially be made more effective by transferring these tasks from the spatial to the temporal domain. This includes the presentation of text but also the selection from menus. The goal of this thesis is to explore how to realize the transformation from the spatial to the temporal domain, what parameters to consider and what sensor data, interaction possibilities, and contextual information are required give the user a sense of control. One specific aspect is how to deal with task interruptions and how to resume tasks.



Reactive Compression Feedback
[Bachelor Thesis, Student: Peter Brandes, Supervisor: Henning Pohl ]

With our existing compression feedback prototype, we would like to explore reactive interactions. Here users press on the pressure cuff, which reacts by letting out some of the pressure. By varying the release pattern, users can perceive several different stimuli. The feedback here is reactive in that it only occurs once users specifically query state.



Smartwatch Posture Tracking
[Master Thesis, Student: Christian Domin, Supervisor: Michael Rohs ]

Navigating through large information spaces on smartwatches is hard. A significant amount of touch screen interaction is necessary. If the absolute position and orientation of a smartwatch with respect to the body position of the user could be determined, then information navigation could presumably be performed more efficiently. It is difficult to determine absolute smartwatch position from acceleration data alone. Hence this thesis investigates which additional sensors can support smartwatch posture tracking to make it simpler and more reliable. Initial ideas include using trajectories (history information) instead of just end positions, using absolute distance sensors (time-of-flight sensors), and taking advantage of smartwatch interactions for calibration. The goal of this thesis is to develop a solution involving a small set of sensors (to be added to the smartwatch and/or strap) for smartwatch posture tracking and to develop an example application.



2015
A Context-Based Approach to a Proactive Launcher for Mobile Devices
[Master Thesis, Student: Andreas Möhring, Supervisor: Michael Rohs ]

Due to the growing number of applications being installed on smartphones it is becoming harder for users to manage all of those applications and to find the right one at the right time. Context-aware proactive app launchers that utilize machine learning to predict the applications that are most likely to be opened next are one solution to this problem. However, it is still not clear how exactly to design these best and especially how to visualize the predictions to achieve the best user experience, i.e. in a way that helps users without confusing them and taking away control. In this thesis I report about SmartLauncher, a prototype of such a system, and a field study I conducted, utilizing visual salience to guide users in an unobtrusive way. The study shows that a combination of good predictions and this subtle way of assistance can improve the mean speed of finding apps by up to 8% while being superior in terms of user acceptance to other approaches utilizing e.g. rearrangement. Part of this thesis has also been submitted as a scientific paper to the 17 th International Conference on Human-Computer Interaction with Mobile Devices and Services (MobileHCI 2015). Thus some parts can be found in both documents and are not explicitly cited.



A Mobile Feedback and Microlearning System for University courses
[Master Thesis, Student: Marcus Wobig, Supervisor: Michael Rohs ]

Diese Arbeit untersucht, wie mithilfe eines crowdbasierten Ansatzes das Problem der geringen Beteiligung von Studenten in Universitätsvorlesungen vermindert werden kann. Studenten haben nur wenige Möglichkeiten, dem Dozenten direktes Feedback zu geben, während einer Vorlesung meist ausschließlich verbal. Viele Studenten trauen sich nicht eine Frage zu stellen, beispielsweise aus Angst von den Kommilitonen als “dumm“ wahrgenommen zu werden, den Fluss der Vorlesung zu unterbrechen, oder weil sie mehr Zeit benötigen, um über die Inhalte nachzudenken und eine Frage zu formulieren. So bleiben viele Fragen der Studenten ungestellt, die Frontalvorlesung wird im Sinne des Wortes genutzt: Der Dozent trägt vor und die Studenten schreiben den Tafelinhalt mit. In dieser Arbeit wird ein System entwickelt, das Fragen und Antworten der Studenten erfasst und automatisiert in ein Quiz umgewandelt. Das Quiz gibt den Studenten Feedback über ihren aktuellen Lernstand und ihre Fortschritte in der Auseinandersetzung mit den Vorlesungsinhalten. Studenten können die Lerninhalte auch mobil bearbeiten (Microlearning) und sich somit aktiver damit auseinandersetzen. Der Dozent erhält Feedback, zu welchen Vorlesungsinhalten es viele Fragen gibt. In einer Evaluation wird das entwickelte System getestet, durch die Funde kann es dann noch weiter verbessert werden. Damit ergibt sich ein System, welches in Vorlesungen oder ähnlichen Kursen zur Unterstützung des Lern- / Lehrprozesses eingesetzt werden kann. Durch die Automatisierung wird dabei dem Dozenten ein großer Teil an Arbeit abgenommen, wodurch mehr Zeit für die inhaltliche Vermittlung von Ideen und Konzepten bleibt.



A Zooming Emoji Keyboard
[Bachelor Thesis, Student: Dennis Stanke, Supervisor: Henning Pohl ]

This thesis implemented a zooming UI for a novel emoji keyboard on Android. Enabled by current high resolution phone displays, this allows showing all emoji at once and quick selection with as few as two taps.



Biofeedback for User Evaluation – Collecting and Analyzing Data of an Arduino-Based Low-Cost Biofeedack System
[Bachelor Thesis, Student: Björn Fiedler, Supervisor: Max Pfeiffer ]

In user studies it is often hard to measure continuous user feelings such as stress, frustration, or satisfaction. In addition to the traditional evaluation methods Biofeedback can be used to get a broad understanding of the user. Biofeedback are processed data of physical functions of the user such as blood pressure, heart rate, galvanic skin response (GSR), electrocardiography (EKG), electroencephalography (EEG), or electromyography (EMG) data. In this thesis, first, a literature review should be done; second, an Arduino-based Biofeedback evaluation tool should be implemented; and third, the prototype should be tested in a user study. If you are interested in Arduino programming, user evaluation, and prototyping, then contact me.



Casual Output for Smartwatches
[Bachelor Thesis, Student: Justyna Medrek, Supervisor: Henning Pohl ]

Smartwatches are hogging our attention with a constant buzzing of notifications. We want to explore scattering light in the arm for a lower intensity kind of feedback that only grabs attention mildly.



Categorical Emoji Keyboard
[Bachelor Thesis, Student: Philipp Seelig, Supervisor: Henning Pohl ]

Instead of presenting emoji in a list, this thesis explores how category labels, such as positive and negative can help in emoji text entry.



Compression Feedback Gaming
[Bachelor Thesis, Student: Franziska Hoheisel, Supervisor: Henning Pohl ]

We are going to design a pervasive game where interacting with virtual objects can result in real-life encumberance.



Digital Games for Voice Taining
[Bachelor Thesis, Student: Kevin Raetz, Supervisor: Markus Krause ]

The process of learning can be repetitive and boring. An approach to counteract this is using digital games to complement the learning task or to develop games that teach the required skill and knowledge. A problem regarding this approach is that only certain people enjoy certain games and it is not given that all participants in a class are appealed by the chosen game. There is work that investigates how to make applications and especially games more accessible by using pitch and even using games played by singing in an educational context. This thesis builds upon these works in that it develops a functional prototype which helps the user to learn to sing in tune by providing an interface that maps pitches onto key input which is used to play a game that is not build to be played by vocal input. For the thesis the game Tekken 3 was chosen and a mapping for the character Hwoarang was created. Tekken 3 is chosen because of its action-heavy and fast-paced concept what should provide good insight about the possibility to conserve the fun of playing the game even though the game concept is violated by making it turn-based. It is expected that the learner finds this more engaging and enjoyable than a regular „sing in tune“ application or the gamification of such application, since he is playing a game with all its features.



Entwurf und Analyse einer interaktiven Visualisierung für planare Graphen höherer Ordnung
[Bachelor Thesis, Student: Thiemo Fischer, Supervisor: Michael Rohs ]

Many different disciplines use node-link diagrams as a preferred metod of visualization for relational data. Over the years various aesthetic criteria for these visualizations emerged. Most important is the demand to draw graphs crossing-free. No edges are supposed to cross each other. In this bachelor thesis a universal data model for node-link diagrams is developed. It harmonizes the concepts of similar models and adds the ability for representing faces and three dimensional domains as well. Subsequently an algorithm is engineered. It produces a mouse-controllable, crossing free node-link diagram of the named data model. The technique is based on using planar embeddings of graphs into higher genus surfaces. Finally the utility, aesthetics and limits of the procedure are discussed.



Eye-Tracking for Casual Interaction with a Phone
[Bachelor Thesis, Student: Christoph Lenz, Supervisor: Henning Pohl ]

Your phone is lying on a table and you want to check who sent you that text without picking it up. Write some code to combine our eye-tracker with our motion tracker to implement a way to interact with the phone just with gaze.



Haptic Feedback in 3D Interaction – Simulating Object Properties Using EMS
[Bachelor Thesis, Student: Wei Chen, Supervisor: Max Pfeiffer ]

In 3D interaction haptic feedback is facing challenges to increase realism. In previous projects we investigated a novel approach to simulate haptic object properties such as size with electrical muscle stimulation. In this project we would like to use 3D projection or head amounted displays to investigate novel interaction methods for our haptic feedback approach. If you are interested in new haptic feedback methods, 3D programming, prototyping, and user study design, contact me.



Haptisches Feedback in 3D Interaktionen- Simulation von Objekteigenschaften mittels EMS
[Bachelor Thesis, Student: Martin Buntrock, Supervisor: Max Pfeiffer ]

In this bachelor thesis the use of haptic feedback using electrical muscle stimulation (EMS) for simulating object properties is considered. A prototype capable of stimulating up to two muscles is used to simulate object sizes by contracting forearm muscles. The system setup and prototype are described and the precision of the simulation of object sizes is evaluated using a user study. The user study is described in detail and the results are discussed. Problems concerning the implementation of a weight simulation are presented and the limits of the achievable feedback using this prototype are discussed. Finally an outlook based on the findings is given.



Motivationsverstärkung bei Studenten in Onlinekursen durch Gamification
[Bachelor Thesis, Student: Marc Mogalle, Supervisor: Markus Krause ]

Gamification wird häufig verwendet, um die Bearbeitung von Aufgaben für die Teilnehmer angenehmer zu gestalten. Auf dieser Grundlage wollen wir unsere Hypothese, dass Gamification auch die Motivation der Bearbeitenden verstärkt, überprüfen. Dazu gestalten wir die Plattform eines Onlinekurses um und führen damit zwei Experimente durch, in denen die Teilnehmer in drei Gruppen (Standard, Gamified und Social-Gamified) Teile eines Onlinekurses bearbeiten. In der Benutzerstudie hat sich herausgestellt, dass ein signifikanter Unterschied zwischen der Standard und der Gamified-Gruppe, sowie von der Standard- und der Social-Gamified-Gruppe in der Bewertung der Nutzer vorliegt. Die Gamified und Social-Gamified-Varianten wurden in den Punkten Spaß an der Nutzung der Plattform und Design signifikant besser bewertet. Zusätzlich haben die Social-Gamified-Nutzer angegeben, den Kurs weiterempfehlen zu wollen, sowie mehr Spaß am Kurs selber gehabt zu haben, als die Vergleichsgruppen. Dies kann man auf die intrinsische Motivation durch Freude an der Nutzung der Plattform zurückführen.



Pedestrian Navigation – Controlling Walking Direction using EMS
[Bachelor Thesis, Student: Peter Denis, Supervisor: Max Pfeiffer ]

In previous projects we investigated a novel approach to control pedestrians’ walking direction for navigation. We showed that controlling the direction with electrical muscle stimulation works in outdoor navigation scenarios. As a follow-up project we will use our prototype to investigate the precision of that approach. In this thesis a differential GPS-based navigation prototype should be designed and developed for a mobile phone and tested in outdoor user studies. You will get a deeper understanding of novel haptic feedback methods, differential GPS, mobile development, prototyping, and user study design.



Plagiarism Detection in Student Programming Assignments
[Bachelor Thesis, Student: Christian Domin, Supervisor: Markus Krause ]

In this thesis we design a plagiarism detection tool, which detects plagiarism in student programming assignments. This system increases the prediction accuracy with dynamic removal of parts in assignments, which are part in almost every assignment. We call this common ground. This approach enables the system to distinguish between normal similarities and plagiarism in relation to the course. The technique used by the system is language independent. However we can achieve a similar detection accuracy like the plagiarism detection tool Moss.



Simulation von Texturen mit EMS-basiertem haptischem Feedback für interaktive Oberflächen
[Bachelor Thesis, Student: Le Duy Linh Phan, Supervisor: Max Pfeiffer ]

In this bachelor thesis a possibility for simulating textures with haptic feedback on interactive surfaces using eletric muscle stimulation (EMS) is introduced. With EMS a user can be controlled using the force of their own muscles and they perfom movements according to prefabricated patters on the surface to simulate textures. A prototype with an Arduino Nano as base unit has been designed which can communicate with a surface using WLAN and which will trigger a user’s hand movement on touching a texture on the surface. A user case study is used to evaluate if texture simulation with EMS is possible using the prototype.



Supporting audiometric testing for children through a computer game
[Bachelor Thesis, Student: Marco Herbst, Supervisor: ]

Cortical evoked response audiometry (CERA) is an objective audiometric test to determine hearing loss. In order to capture good measurements, participants needs to remain calm and listen carefully to the played sounds. Children tend not to stay calm and listen carefully. Thus, the test is only administered to adults at the Medical School Hanover (MHH). The interactive computer game CERAtronis developed to support testing children. The aim of this thesis is to use a serious game in order to increase the attention level and obtain valid measurement data from children during audiometric testing. The CERA was given to 4 children and 5 adults with the game. The generated average curves for the different dB-values are analyzed and observed for the N1-P2 complex. The results indicate that the average curves of adults with the CERAtron game provide a N1-P2 complex, but the data from children does not. Nevertheless, the children manage to finish the test with the CERAtron game which confirmed that the attention level was raised. However, future research could improve the test by conducting more measurements during the game. This might allow to receive improved average curves and detect the N1-P2 complex in children data as well.



Universal Haptic Touch – Simulating Haptic Touch Feedback on Large, Small, and Mobile Touch Devices
[Bachelor Thesis, Student: Eike Schlicht, Supervisor: Max Pfeiffer ]

Nowadays haptic feedback is located in the device itself. In a new approach we investigate haptic feedback for touch input that is located on the user. In our current work we are using electrical muscle stimulation for haptic feedback on multi-touch surfaces and investigate different feedback patterns. In a follow-up project we would like to extend this approach to multiple devices and add new patterns. In this thesis you will get a deeper understanding of haptic feedback with electrical muscle stimulation, multiple devices development, and user study design.



2014
Casual Interaction with a Bracelet
[Master Thesis, Student: Karoline Busse, Supervisor: Henning Pohl ]

Interaction with wearables nicely affords switching between focused and casual interactions. A bracelet, for example, is mostly in the periphery of our attention. However, a simple arm movement can bring it into focus. Here we would like to explore how to build a prototype bracelet device that can support different interactions at each of those attention levels. In a smart-home scenario, we furthermore will investigate specific ways to control lighting with varying levels of engagement.



Comparison of Object-Oriented and Functional Programming for GUI Development
[Master Thesis, Student: Eugen Kiss, Supervisor: Michael Rohs ]

Traditionally, the object-oriented paradigm has been considered a good fit for designing and developing graphical user interfaces (GUIs). A large number of GUI frameworks are based on object orientation (OO). Recently, functional programming (FP) has become more popular for mainstream development. This thesis is concerned with a comparison of the object-oriented approach and the functional approach applied to the development of graphical user interfaces. To limit the scope, the thesis focuses on languages that are available on the Java Virtual Machine. In particular, the main candidates are Java/Swing on the object-oriented side, and Clojure/Swing and Clojure/Seesaw on the functional side. If time allows, Scala/Swing might be considered as a hybrid object-oriented and functional language.



Design and Implementation of a Wearable Prototype for EMS-Based Pedestrian Navigation
[Bachelor Thesis, Student: Tim Dünte, Supervisor: Max Pfeiffer ]

In this work, two options are presented how pedestrian navigation can take place with electrical muscle stimulation (EMS). The first approach involves the stimulation of forearm muscles with EMS, while the second approach involves the stimulation of a thigh muscle per leg. These two possibilities will be presented for each a corresponding concept, in which the used muscles and a possible encoding of the information for the navigation will be discussed. For the generation and control of the EMS-signals, the implementation of a wearable prototype is presented. This was created based on an Arduino Uno, a self-made circuit and a commercially available EMS unit. This EMS-system will allow controlling the intensity of the EMS-signal and a communication with a mobile device, for example a smartphone. The created EMS-system and the second approach will be evaluated in a laboratory study. The study is intended to make quantitative and qualitative statements, whether navigation of the user over the thigh muscle is possible and whether navigation could take place in everyday life in this way.



Haptic Feedback for Mobile Augmented Reality Interactions with Physical Objects
[Master Thesis, Student: Oliver Beren Kaul, Supervisor: Max Pfeiffer ]

Augmented reality (AR) aims at providing additional information about physical objects. This information is primarily displayed as graphical overlays that are aligned with these objects. Currently, it is difficult to generate haptic output in augmented reality interactions. Vibrotactile output is common, for example with mobile phones, but is limited in the kind of output it can generate. Mechanical haptic output devices, such as the Phantom device, generate high-fidelity haptic output, but are expensive, bulky, and not mobile. This work aims at improving this situation by exploring electrical muscle stimulation (EMS) as novel kind of lightweight haptic output mechanism. A concrete task is to use virtual haptic feedback for guiding users relative to a physical object in augmented reality situations. Potential scenarios are educational (e.g., exploring cables and functional units in a motor), maintenancerelated (e.g., showing how to twist and turn a replacement part such that it fits into a target position), or related to exhibitions (e.g. guiding the user towards a building in a city model).



Multi-Scale Around-Device Output
[Bachelor Thesis, Student: Bastian Krefeld, Supervisor: Henning Pohl ]

Previously, embedding LEDs in device bezels has been explored at coarse and static resolutions. We would like to investigate more fine-grained around-device output. Thus, we'll use conventional displays and route those to the edge using fibre optics to simulate full-output bezels. Possible use-cases include offscreen-visualization and casual interactions.



Multi-Touch Text Entry for Mobile Devices
[Master Thesis, Student: Minh Anh Truong, Supervisor: Michael Rohs ]

Text entry on mobile devices with capacitive touch screens is in widespread use. However, limited display sizes and lack of tactile feedback make mobile text entry challenging for users. A number of research efforts have tried to improve mobile text entry by, e.g., using language models to allow for imprecise typing, using different keyboards for specific tasks, finding optimized keyboard layouts, and developing gesture-based text entry systems. Less emphasis has been put on using the capabilities of multi-touch screens for text input in the sense that disambiguation between characters can be achieved by touching a key with different numbers of fingers. This thesis is going to explore the possibilities of multi-touch text input on mobile devices. This includes investigating the accuracy and speed of rapid changes between single- and multiple-finger touches. It also requires optimizing keyboard layouts. The final variant should be implemented on Android devices as a replacement of the standard keyboard.



Semantic Similarity - Comparing Crowdworkers with Experts
[Bachelor Thesis, Student: Nils Batram, Supervisor: Markus Krause ]

Humans have a natural ability for language processing which computer algorithms lack. However, for some areas of natural language processing, computer algorithms can provide a fast and cheap alternative to manpower. Instead of conducting a conventional survey, distribution of the workload over the internet to a large group of independent workers (crowdworkers) can increase flexibility and reduce costs. This thesis analyzes the performance of crowdworkers on semantic similarity tasks. To this end, a crowdworker study is conducted and the results are compared to offline contributors and computer algorithms. The effects of quality control are investigated by repeating the experiment under various quality control conditions. This thesis will show that, with quality control mechanisms in place, crowdworkers can provide results close in quality to offline contributors. It will also provide evidence that current algorithms outperform single human contributors, but still cannot compete with aggregated results gathered from groups of contributors.



Simulation von haptischem Feedback in 3D Interaktionen: Unterscheidung von Objektgrössen durch EMS
[Bachelor Thesis, Student: Gil Engel, Supervisor: Max Pfeiffer ]

In this bachelor thesis a system to simulate haptical feedback by electric muscle stimulation will be described. With this system it is possible to make virtual objects perceptible. A approach will be introduced that uses two muscles on the lower arm. The EMS Signals gets controlled by a self designed prototyp which will be decribed in detail. Portability of the prototyp gets reached by designing it small and with the use of portable technics like WiFi. With a case study the efficiency of the approach will be measured. The study will be decribed more in detail. Furthermore the results get presented precisely. Finally a discussion of the results will be made and an outlook be given.



Thumb Input for Tablet Computers
[Bachelor Thesis, Student: Tim Dannhauer, Supervisor: Michael Rohs ]

When holding a tablet computer the thumbs typically just hold the device. This thesis investigates how the thumbs can be involved in the interaction when navigating through content or playing games. Various sensors will be used to measure thumb movement. The ergonomic possibilities and limitations will be evaluated. Based on these results, new interaction techniques will be developed.



2013
Around-Device In-Air Gestural Interactions
[Bachelor Thesis, Student: Sven Greiner, Supervisor: Henning Pohl ]

For a direct interaction with around-device targets it is neccessary to know the minimal size of a target a user can interact with. In a study the size is determined under the assumption of a good visualization supporting the user in finding the correct location. Measurements result in a sphere of around 40 mm in diameter.