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A narrowing-based theorem prover [chapter]

Ulrich Fraus, Heinrich Hußmann
1991 Lecture Notes in Computer Science  
This work presents a theorem prover for inductive proofs within an equational theory which supports the verification of universally quantified equations. This system, called TIP, is based on a modification of the well-known narrowing algorithm. Particulars of the implementation are stated and
doi:10.1007/3-540-54444-5_118 fatcat:l7wabi2fdjal5nxdxsmf2utegu

Graphical development of consistent system specifications [chapter]

Bernhard Schätz, Heinrich Hußmann, Manfred Broy
1996 Lecture Notes in Computer Science  
While formal methods have promised essential benefits for the software development process, industrial development reality nevertheless relies mainly on informal and especially graphical description techniques. This article argues that formal techniques are indeed useful for practical application, but they should be put to indirect use. To demonstrate this approach, two pragmatic graphical description techniques, taken from the field of telecommunication, are analyzed regarding their
more » ... content and their application in the process of specification development; as a result these techniques are formally defined. Based on the formal definition, "safe" development steps and their graphical counterparts are introduced. This yields a graphical development method which relies on precise formal foundations.
doi:10.1007/3-540-60973-3_91 fatcat:vmd5aqbyq5apvj36zdutlsgivu

Tangible Interaction with Light: A Review

Yanhong Li, Beat Rossmy, Heinrich Hußmann
2020 Multimodal Technologies and Interaction  
Light is an important means of information representation and feedback in Human–Computer Interaction (HCI), and light-emitting interaction elements are omni-present. We address here the interplay of light and tangible interaction with specifically designed objects. The goal of such designs is to support an embodied, emotional and engaged interaction experience integrated into the physical surroundings. The specific combination of tangible interaction and light as a medium is used in several
more » ... oaches, but a systematic overview of this research area still does not exist. In order to understand the essence, process and result of tangible interaction with light, we conducted a systematic literature review of 169 studies of tangible interaction with light over the past 20 years. Our results provide a demographic overview of the research, but foremost analyze their concepts, purposes, conceptual frameworks, user contexts, interaction behaviors and problems addressed by tangible light. Three important findings were obtained: (1) Tangible interaction with light has been used for diverse purposes, contexts and interactions; (2) Tangible light has addressed problems: weak interaction, don't know how to interact, interaction lacks innovation, collaborative interaction, remote tangible interaction, and emotional interaction; (3) Current research in this area can be classified as "wild theory" in conceptual research frameworks, which means it emphasizes very much on innovation. The most important contribution of this work is the systematic review in itself, but the findings of our work also give some indications on new ways and future trends for tangible interaction, when combined with light as a medium.
doi:10.3390/mti4040072 fatcat:n2mk6ech2zbjpmil6io26pdryi

Nondeterministic algebraic specifications and nonconfluent term rewriting

Heinrich Hussmann
1992 The Journal of Logic Programming  
D Algebraic specifications are generalized to the case of nondeterministic operations by admitting models with set-valued functions (multialgebras). General (in particular, nonconfluent) term-rewriting systems are studied as a specification language for this semantic framework. A calculus for nondeterministic specifications is given which is similar to term rewriting but which employs an additional determinacy predicate. Soundness, ground completeness, and initiality results are given. Small
more » ... mples illustrate the range of possible applications. a
doi:10.1016/0743-1066(92)90026-y fatcat:l5rvzgbizzfyhjd5dyljx6hlmq

Model-Driven Development of Interactive Multimedia Applications with MML [chapter]

Andreas Pleuss, Heinrich Hussmann
2011 Studies in Computational Intelligence  
There is an increasing demand for high-quality interactive applications which combine complex application logic with a sophisticated user interface, making use of individual media objects like graphics, animations, 3D graphics, audio or video. Their development is still challenging as it requires the integration of software design, user interface design, and media design. This chapter presents a model-driven development approach which integrates these aspects. Its basis is the Multimedia
more » ... g Language (MML), which integrates existing modeling concepts for interactive applications and adds support for multimedia. As we show, advanced multimedia integration requires new modeling concepts not supported by existing languages yet. MML models can be transformed into code skeletons for multiple target platforms. Moreover, we support the integration of existing professional multimedia authoring tools into the development process by generating code skeletons which can be directly processed in authoring tools. In this way the advantages of both -systematic model-driven development and support for creative visual design -are combined. ---------
doi:10.1007/978-3-642-14562-9_10 fatcat:zc22z55gpbaihgwxyo3zdmr2im

Mobia Modeler

Florence Balagtas-Fernandez, Max Tafelmayer, Heinrich Hussmann
2010 Proceedings of the 15th international conference on Intelligent user interfaces - IUI '10  
The development of mobile applications has now extended from mobile network providers into the hands of ordinary people as organizations and companies encourage people to come up with their own software masterpieces by opening up APIs and tools. However, as of the moment, these APIs and tools are only usable by people with programming skills. There is a scarcity of tools that enable users without programming experience to easily build customized mobile applications. We present in this paper a
more » ... ol and framework that would enable non-technical people to create their own domain-specific mobile applications. The tool features a simple user-interface that features configurable components to easily create mobile applications. As a proof of concept, we focus on the creation of applications in the domain of mobile health monitoring. In the future, we would like to extend our work to cover other domains as well.
doi:10.1145/1719970.1720008 dblp:conf/iui/Balagtas-FernandezTH10 fatcat:z7xexlnmcjaczbxhrm76gumigy

A Qualitative Post-Experience Method for Evaluating Changes in VR Presence Experience Over Time [article]

Christian Mai, Heinrich Hußmann
2019 arXiv   pre-print
A particular measure to evaluate a head-mounted display (HMD) based experience is the state of feeling present in virtual reality. Interruptions of a presence experience - break in presence (BIP) - appearing over time, need to be detected to assess and improve an application. Existing methods either lack in taking these BIPs into account - questionnaires - or are complex in their application and evaluation - physiological and behavioral measures -. To provide a practical approach, we propose a
more » ... ost-experience method in which the users reflect on their experience by drawing a line, indicating their experienced state of presence, in a paper-based drawing template. The amplitude of the drawn line represents the variation of their presence experience over time. We propose a descriptive model that describes temporal variations in the drawings by the definition of relevant points over time - e.g., putting on the HMD -, phases of the experience - e.g., transition into VR - and parameters - e.g., the transition time -. The descriptive model enables us to objectively evaluate user drawings and represent the course of the drawings by a defined set of parameters. An exploratory user study (N=30) showed that the drawings are very consistent, the method can detect all BIPs and shows good indications for representing the intensity of a BIP. With our method practitioners and researchers can accelerate the evaluation and optimization of experiences by evaluating BIPs. The possibility to store objective parameters paves the way for automated evaluation methods and big data approaches.
arXiv:1905.05673v1 fatcat:flsdc5wsnjgx5fq3vmxgyptbgm


Alexander De Luca, Katja Hertzschuch, Heinrich Hussmann
2010 Proceedings of the 28th international conference on Human factors in computing systems - CHI '10  
Automated teller machine (ATM) frauds are increasing drastically these days. When analyzing the most common attacks and the reasons for successful frauds, it becomes apparent that the main problem lies in the PIN based authentication which in itself does not provide any security features (besides the use of asterisks). That is, security is solely based on a user's behavior. Indirect input is one way to solve this problem. This mostly comes at the costs of adding overhead to the input process.
more » ... present ColorPIN, an authentication mechanism that uses indirect input to provide security enhanced PIN entry. At the same time, ColorPIN remains a one-to-one relationship between the length of the PIN and the required number of clicks. A user study showed that ColorPIN is significantly more secure than standard PIN entry while enabling good authentication speed in comparison with related systems.
doi:10.1145/1753326.1753490 dblp:conf/chi/LucaHH10 fatcat:s7zzjye5mngbvex5t27e27zlze

Modular architecture for a toolset supporting OCL

Heinrich Hussmann, Birgit Demuth, Frank Finger
2002 Science of Computer Programming  
The practical application of the object constraint language (OCL), which is part of the UML speciÿcation since version 1.1, depends crucially on the existence of adequate tool support. This paper discusses general design issues for OCL tools. It is argued that the nature of OCL will lead to a large variety of tools, applied in combination with a variety of di erent UML tools. Therefore, a exible modular architecture for a UML=OCL toolset is proposed. The paper reports on the ÿrst results of an
more » ... ngoing project which aims at the provision of such an OCL toolset that is available as free software.
doi:10.1016/s0167-6423(02)00032-1 fatcat:qgriq6bri5dahgkvkfborwviwu


Nada Terzimehić, Mohamed Khamis, Florian Bemmann, Heinrich Hussmann
2018 Extended Abstracts of the 2018 CHI Conference on Human Factors in Computing Systems - CHI '18  
Previous studies have shown that when individuals join groups for lunch, they tend to conform to the decision of the group. As result, people do not always have the chance to pick the food they wish for, which in turn may have negative consequences, such as not abiding to healthy diets. To address this problem, we created Lunchocracy, an anonymous decision support tool for lunch spots in a workplace based on feedback from a focus group with 7 participants. The tool implements a conversational
more » ... ype-bot, Lunchbot, that allows users to express interest in joining lunch and to vote for diners to eat at. We deployed the tool for four weeks with 14 participants from the same university department. Post-interviews with 5 participants revealed an overall satisfaction with Lunchocracy, in particular due to it structuring the lunch decision-making and saving time. We discuss how the use of Lunchocracy can positively influence the group's eating dynamics.
doi:10.1145/3170427.3188626 dblp:conf/chi/TerzimehicKBH18 fatcat:lull4onwhjazzaq4gq5goq5oc4

Look into my eyes!

Alexander De Luca, Martin Denzel, Heinrich Hussmann
2009 Proceedings of the 5th Symposium on Usable Privacy and Security - SOUPS '09  
Authentication systems for public terminals -and thus public spaces -have to be fast, easy and secure. Security is of utmost importance since the public setting allows manifold attacks from simple shoulder surfing to advanced manipulations of the terminals. In this work, we present Eye-PassShapes, an eye tracking authentication method that has been designed to meet these requirements. Instead of using standard eye tracking input methods that require precise and expensive eye trackers,
more » ... pes uses eye gestures. This input method works well with data about the relative eye movement, which is much easier to detect than the precise position of the user's gaze and works with cheaper hardware. Different evaluations on technical aspects, usability, security and memorability show that EyePassShapes can significantly increase security while being easy to use and fast at the same time.
doi:10.1145/1572532.1572542 dblp:conf/soups/LucaDH09 fatcat:lqfrqsayg5eetb4haw2ynzymoy

Evaluation of User-Interfaces for Mobile Application Development Environments [chapter]

Florence Balagtas-Fernandez, Heinrich Hussmann
2009 Lecture Notes in Computer Science  
This paper discusses about the different user-interfaces of mobile development and modeling environments in order to extract important details in which the user-interfaces for such environments are designed. The goal of studying such environments is to come up with a simple interface which would help people with little or no experience in programming, develop their own mobile applications through modeling. The aim of this research is to find ways in order to present the user interface in a
more » ... manner such that the balance between ease-of-use and ease of learning is achieved.
doi:10.1007/978-3-642-02574-7_23 fatcat:oaeu2sbmlbbejbvt4b3lws56ra


Sarah Tausch, Doris Hausen, Ismail Kosan, Andrey Raltchev, Heinrich Hussmann
2014 Proceedings of the 8th Nordic Conference on Human-Computer Interaction Fun, Fast, Foundational - NordiCHI '14  
To ensure the productivity of brainstorming, group members have to observe several rules. Nevertheless, problems such as free riding or imbalanced participation can occur. We present Groupgarden, a metaphorical group mirror providing feedback about individual as well as group performance. We conducted two user studies. We could validate the effectivity of Groupgarden in a preliminary study that compared brainstorming sessions supported by Groupgarden with sessions without additional support.
more » ... ults show that the group mirror effectively supports the compliance to particular brainstorming rules and participation is more balanced compared to the baseline. In a second study, we examined the influence of the location of the feedback, wall vs. table, on group behavior. Our results indicate that the location does not influence efficiency of brainstorming, while each location has different benefits. Feedback on a wall seems less disturbing and puts less pressure on the group while a group mirror on a table facilitates communication and collaboration.
doi:10.1145/2639189.2639215 dblp:conf/nordichi/TauschHKRH14 fatcat:rfa2u7beq5ckfn2gdwu6pggeuy

Towards understanding ATM security

Alexander De Luca, Marc Langheinrich, Heinrich Hussmann
2010 Proceedings of the Sixth Symposium on Usable Privacy and Security - SOUPS '10  
With the increase of automated teller machine (ATM) frauds, new authentication mechanisms are developed to overcome security problems of personal identification numbers (PIN). Those mechanisms are usually judged on speed, security, and memorability in comparison with traditional PIN entry systems. It remains unclear, however, what appropriate values for PIN-based ATM authentication actually are. We conducted a field study and two smaller follow-up studies on real-world ATM use, in order to
more » ... de both a better understanding of PIN-based ATM authentication, and on how alternative authentication methods can be compared and evaluated. Our results show that there is a big influence of contextual factors on security and performance in PINbased ATM use. Such factors include distractions, physical hindrance, trust relationships, and memorability. From these findings, we draw several implications for the design of alternative ATM authentication systems, such as resilience to distraction and social compatibility.
doi:10.1145/1837110.1837131 dblp:conf/soups/LucaLH10 fatcat:lcanuqrbpbapnaruulsqs7ap6i


Alexander De Luca, Emanuel von Zezschwitz, Heinrich Hußmann
2009 Proceedings of the 27th international conference on Human factors in computing systems - CHI 09  
Authentication in public spaces is a risky task. Frauds on cash machines (ATMs) are not uncommon nowadays. The biggest group of attacks is observation attacks, which focus on recording the input done by the users. In this work, we present VibraPass, a system created to be resilient against observation attacks using tactile feedback provided by the users' own mobile devices. In this way, secret information is shared between the terminal and the users to add an overhead of 'lies' to the input
more » ... h makes it hard for attackers to steal the real PIN or password. We present an evaluation, which shows that VibraPass has the potential to replace current authentication systems due to increased security combined with reasonable input speed and error rates.
doi:10.1145/1518701.1518840 dblp:conf/chi/LucaZH09 fatcat:cmo3zwkkhzhermro2j26k63mny
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