Publikationen von Markus Krause

Plagiarism in online learning environments has a detrimental effect on the trust of online courses and their viability. Automatic plagiarism detection systems do exist yet the specific situation in online courses restricts their use. To allow for easy automated grading, online assignments usually are less open and instead require students to fill in small gaps. Therefore solutions tend to be very similar, yet are then not necessarily plagiarized. In this paper we propose a new approach to detect code re-use that increases the prediction accuracy by dynamically removing parts in assignments which are part of almost every assignment—the so called common ground. Our approach shows significantly better F-measure and Cohen's Kappa results than other state of the art algorithms such as Moss or JPlag. The proposed method is also language agnostic to the point that training and test data sets can be taken from different programming languages.

Many MOOCs report high drop off rates for their students. Among the factors reportedly contributing to this picture are lack of motivation, feelings of isolation, and lack of interactivity in MOOCs. This paper investigates the potential of gamification with social game elements for increasing retention and learning success. Students in our experiment showed a significant increase of 25% in retention period (videos watched) and 23% higher average scores when the course interface was gamified. Social game elements amplify this effect significantly – students in this condition showed an increase of 50% in retention period and 40% higher average test scores.

We present a novel way to recognize users by the way they press a button. Our approach allows low-effort and fast interaction without the need for augmenting the user or controlling the environment. It eschews privacy concerns of methods such as fingerprint scanning. Button pressing behavior is sufficiently discriminative to allow distinguishing users within small groups. This approach combines recognition and action in a single step, e.g., getting and tallying a coffee can be done with one button press. We deployed our system for 5 users over a period of 4 weeks and achieved recognition rates of 95% in the last week. We also ran a larger scale but short-term evaluation to investigate effects of group size and found that our method degrades gracefully for larger groups.

Parkinson's disease causes a wide range of motor impairments that also affect speech. Even patients with mild speech motor disabilities do suffer from symptoms such as reduced dynamics, melody, tone, pace and continuity of speech. Besides invasive or drug based treatments, effective logopedic treatments do exist. However, constant training is a key factor for this type of therapy. Digital games can be one way to enhance patient's motivation for repetitive exercises both in therapy sessions and in prolonged use at home. This paper examines the possibilities of such a digital logopedic game developed for PD patients and reports first promising study results that indicate an increased peak voice loudness of the players' voice when playing the game.

A recurrent challenge for human computation is motivation. Motivation is not only a prevailing topic for crowd based human computation it is also multifarious. Contributors support human computation projects for money, fun, and many other reasons. Probably the most appealing motivation from a requester’s perspective is an intrinsic interest in the task itself, although this is a rare situation. Therefore, when designing a human computation system a key challenge to accept and handle is to offer a valuable reward for contributors. One possible approach to this challenge is to design human computation systems in a way that makes their use an inherently pleasurable experience. A powerful concept to make tasks more pleasurable is to use game design to add playful elements to the task or merge the task completely into a digital game. This chapter describes concepts, methods, and pitfalls of this approach. It will give hints to identify suitable tasks, design an overall strategy, and deal with the evaluation of data in playful human computation systems.

In recent years crowd-based and human computation systems have attracted increasing attention in science and industry. For applications that are driven by input from a multitude of human raters, ensuring data reliability and organizing an interactive workflow constitute a new challenge. In this paper we describe a novel approach to ensure data quality in crowd-based and human computation systems. The proposed algorithm features the potential for direct feedback and interactivity while producing little computational overhead.

With the advent of mobile games and the according growing and competitive market, game user research can provide valuable insights and a competitive edge if methods and procedures are employed that match the distinct challenges that mobile devices, games and usage scenarios induce. We present a summary of parameters that frame the research setup and procedure, focusing on the trade-offs between lab and field studies and the related decision whether to pursue large-scale and quantitative or small-scale focused research accompanied by qualitative methods. We then illustrate the implications of these considerations on real world projects along the lines of two evaluations of different input methods for the action-puzzle mobile game Somyeol: a local study with 37 participants and a mixed design of qualitative and quantitative methods, and the strictly quantitative analysis of game-play data from 117,118 users. The findings underline the importance of small-scale evaluations prior to release.

With recent advances in harnessing the knowledge and skill of large groups of (unknown) network-connected humans, researchers and practitioners have been designing systems that make contributions of users entertaining and more engaging. Game mechanics are being applied to the traditional human computation tasks, such as transcription, classification and labeling. Seminal examples of such applications include ESP game and FoldIt. At the same time, companies seek strategies to include elements of gaming into business processes to increase productivity and engagement of employees. Framing a business goal in the form of a game is also a promising method for motivating newer generations in the workforce.

Research over the past years has shown that machine translation results can be greatly enhanced with the help of mono-or bilingual human contributors, eg by asking humans to proofread or correct outputs of machine translation systems. However, it remains difficult to determine the quality of individual revisions. This paper proposes a method to determine the quality of individual contributions by analyzing task-independent data. Examples of such data are completion time, number of keystrokes, etc. An initial evaluation showed promising F-measure values larger than 0.8 for support vector machine and decision tree based classifications of a combined test set of Vietnamese and German translations.

The scientific study of serious games is a recent development, spanning less than two decades. One aspect in this field is human computation with digital games. The core of the paradigm is to outsource problems that are not yet solvable by conventional computational systems to humans. Therefore, these problems are reformulated into tasks that are then integrated into digital games. The players of the game then solve the problem while playing. Different human computation games have been successfully deployed, but tend to provide a relatively narrow gaming experience. This chapter analyzes the differences between game design for human computation and traditional digital game design. An in-depth consideration of these differences shows that it is a viable approach to build human computation games with a wide range of designs. The key issues of human computation game design are illustrated with the game OnToGalaxy.

A major challenge of human subject research lies in motivating enough subjects to participate in studies. Traditionally, participants are extrinsically motivated, for example by getting paid for their contribution. Together with the effort of organizing and supervising experiments, this renders human subject research either very expensive, or reduces the validity due to small sample sizes. This work describes the method of utilizing playful web-based surveys to intrinsically motivate contributors to participate in studies and illustrates the approach with two examples: a study of the effect of retouching portraits on the perception of human faces and according estimates of wealth and success that was distributed via a single announcement on a social network and attracted more than 2400 participants within a five months period, as well as a study on the perception of a questionnaire in the form of a playful survey as compared to a more traditional online questionnaire, which showed that participants are more likely to recommend playful surveys to friends than normal surveys.

Exergames offer exciting perspectives not only for recreational, but also for therapeutic use. Increasing numbers of older adults in many industrialized countries raise the need for affordable and reliable solutions to help people to stay healthy and fit at advanced ages. While games user research is vital to increasing the quality of game designs and improving game design processes, many research tools are difficult to use with senior gamers, and the target group is especially vulnerable to mistakes both in game design and games user research. We report and classify some of these challenges along with possible approaches, aiming to fuel intensified exchange about methodological experiences among researchers in the field.

Designing digital games is primarily interaction design. This interaction manifests as a meaningful change in the game world. An aspect of a game can only change dynamically with a parametric model of this aspect available. One aspect of digital games is yet missing such a systematic description: the genre of a game is currently only determined by its designer. This paper introduces a new approach that allows for dynamic blending between genres. We describe a set of game mechanics that express the characteristics of different game genres. We extract a parametric model from these mechanics to allow dynamic blending. The paper illustrates the possibilities of this approach with an implementation of a multi-genre-game. It also provides empiric evidence that the described model successfully generates different game genres.

Mobile devices are already an important platform for digital games. These devices need specialized input metaphors as they have various restrictions such as their own hardware capabilities and the lack of external input devices. Especially challenging are fast paced interactions as in Jump and Run games. This paper explores three user inputs for Jump and Run games on mobile devices along the game Somyeol.

Interactive surfaces are only just beginning to break into the market, and they still do not offer the advanced functionality demonstrated with many lab prototypes. The path from a prototype system to a finished product for use in real-world scenarios is a long one, and many obstacles must be overcome. The design of an interactive multitouch table had to address issues like optical recognition, hardware design, and ergonomics. This paper describes in detail the construction of a large, robust multi-touch table called mrT. It will show how to solve major problems of the diffuse illumination technique and other challenges of constructing a large-screen, high-resolution, self-contained interactivemultitouch surface that not only serves as a development system but can be deployed in the real-world. Additionally, to further motivate some of the design decisions, especially why the diffuse illumination technology was chosen, this paper will discuss related on-going research projects on the application side.

The Parkinson’s disease is a neurodegenerative disorder with a range of symptoms such as slowness, rigidity, resting tremor (trembling), and an impairment of postural balance leading to disturbance of gait and falling. Continuous exercises are an effective strategy to maintain the patient’s movement abilities, slowing down the progression of the disease. Self-directed exercises in addition to supervised physiotherapy sessions are not only beneficial, but necessary. This paper presents an approach to support Parkinson’s disease patients in their daily exercises using the playful context of different motionbased digital games adapted from physiotherapy.

Motivation has been one of the central challenges of human computation. A promising approach is the integration of human computation tasks into digital games. Different human computation games have been successfully deployed, but tend to provide relatively narrow gaming experiences. This survey discusses various approaches of digital games for human computation and aims to explore the ties to signal processing and possible generalizations.

Conducting surveys is a costly and time-consuming process. We developed a playful questionnaire that addresses the issue of motivation for voluntary participation. In addition, distributing playful questionnaires on Facebook gives access to basic user data, which may allow employing some of them as quality control questions or simply help to lessen the number of questions.

Game development is a challenging and diverse field. It integrates different disciplines such as computer science, design, art, and psychology. Many different skills are required to create successful games, posing great challenges for education. These challenges also apply to the area of Serious Games with the additional difficulty of adding goals beside entertainment to the design. We report on our experiences with designing and implementing teaching formats to further the development of curricula and formal education in the area of Serious Game development. Our approach combines theoretical as well as practical elements. To reinforce and motivate our students we connect our courses to external events such as game development competitions. Furthermore, we experimented with using meta-games as a way of teaching game design.

Games for rehabilitation are developing rapidly in recent years. It has been shown that utilization of therapy and gaming technology affects positively on the patients’ physical and mental condition. However, to this day there are only few playable games for Parkinson’s disease patients. This paper presents the development process of WuppDi! – a collection of five motion-based games for Parkinson’s disease patients, aimed at supporting their exercises routines in various playful environments. We describe the game design challenges for Parkinson’s disease patients and our solutions used in the games. Finally, we present the results of a conducted field test showing a very positive motivational effect among the majority of the patients but also highlighting remaining issues and technical difficulties, which can be beneficial for the future development in this field.

Each day millions of people play digital games with different motivations. These motivations rang from time beating to deep immersion into a narration or interacting with a community. To address all these different means, a range of game designs is necessary. Traditional human computation games cannot present all these aspects yet. This work will give a game centered view on game design for human computation. To demonstrate the value of this view it will present a fast-paced action game called OnTo-Galaxy along with two different human computation tasks.

Interactive surfaces are only just beginning to break into the market, and they still do not offer the advanced functionality demonstrated with many lab prototypes. The path from a prototype system to a finished product for use in real-world scenarios is a long one, and many obstacles must be overcome. The design of an interactive multitouch table had to address issues like optical recognition, hardware design, and ergonomics. This paper describes in detail the construction of a large, robust multi-touch table called mrT. It will show how to solve major problems of the diffuse illumination technique and other challenges of constructing a large-screen, high-resolution, self-contained interactive multitouch surface that not only serves as a development system but can be deployed in the real-world. Additionally, to further motivate some of the design decisions, especially why the diffuse illumination technology was chosen, this paper will discuss related on-going research projects on the application side.

We present a human computation online game for enabling users to contribute to the creation of a corpus of question-resource pairs for harvesting web-based question answering. Our idea was motivated by the popular 'jeopardy' quiz.

The present work and demonstration system aims at finding an efficient and cost-effective human computation method to expand the linguistic capabilities of interactive games that need it to respond appropriately to the language based input of their users. As a showcase scenario for the experiments conducted, we took interactive fiction applications and examined how the human computation game design and scoring approaches affects the quality of the data gathered. The ensuing analysis of the data confirms our initial hypothesis that game approaches can provide both the qualitative and quantitative data needed for the corresponding interactive games.

Collaborative Tagging is a powerful method to create folksonomies that can be used to grasp/filter user preferences or enhance web search. Recent research has shown that depending on the number of users and the quality of user-provided tags powerful community-driven semantics or "ontologies" can emerge - as it was evident analyzing user data from social web applications such as del.icio.us or Flickr. Unfortunately, most web pages do not contain tags and, thus, no vocabulary that describes the information provided. A common problem in web page annotation is to motivate users for constant participation, i.e. tagging. In this paper we describe our approach of a binary verification game that embeds collaborative tagging into on-line games in order to produce domain specific folksonomies.

For multi-user multi-touch tables with around the table interaction, orientation of items on screen (such as text) is a problem. We address this issue by proposing a technique to detect the location of users around a multi-touch table. We discuss sensors and algorithms to be used, and benefits of the proposed sensors as well as possible applications.

Convincing animations of virtual characters continue to require motion capture technology or extensive skills in manual keyframing. We want to outline a simple yet natural motion capturing method that takes advantage of multitouch input devices to create believable character motion.

In the past many researchers and companies have focused on mastering different multitouch interface technologies, yet there are currently still only few applications that are truly using the full capabilities of multitouch. In this paper we describe our vision for new multitouch interaction metaphors based on finger and hand gestures especially suited for 3d conceptual modeling and show some ideas about the context in which such a multitouch system could be useful.