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2006-17: Scrolling Through Time: Improving Interfaces for Searching and Navigating Continuous Audio Timelines
by Peter Schneider-Kamp 20 Dec '06

20 Dec '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Scrolling Through Time: Improving Interfaces for Searching and Navigating Continuous Audio Timelines Eric Lee, Henning Kiel, Jan Borchers AIB 2006-17 Existing work has produced a variety of techniques to improve interfaces for navigating an audio timeline. These interfaces typically map user input to either a change in play rate, or playback position. Audio feedback while scrolling at arbitrary rates can be provided by: skipping immediately to the new position in the audio; resampling the audio, which introduces pitch-shifts; timestretching the audio to preserve the pitch; or not at all. We conducted a series of user studies to examine the effects of input and feedback type on targeting performance. Position control was found to be, on average, 15-19% faster than rate control when searching for targets 90 to 100 seconds away in the audio timeline. Time-stretching was found to be the best choice in most scenarios, but skipping, and, for specific user groups, resampling, should be used for precise targeting tasks where the audio play rate falls below one-tenth nominal speed.

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2006-16: Selexels: a Conceptual Framework for Pointing Devices with Low Expressiveness
by Peter Schneider-Kamp 13 Dec '06

13 Dec '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Selexels: a Conceptual Framework for Pointing Devices with Low Expressiveness Rafael Ballagas, Jan Borchers AIB 2006-16 As human-computer interaction extends beyond the desktop, the need emerges for new input devices and interaction techniques. However, many novel interaction techniques must be prototyped in a proof-of-concept form, and can suffer from low expressiveness: their ability to convey the intended meaning is limited. We present a new conceptual framework based on selexels that allows application designers to match the expressiveness of the user interface to that of the input device. This allows the user interface to provide a fluid user experience despite the limitations of the input device. A user study validates the framework, shows that selexel-based pointing tasks can be modeled using Fitts' Law, and provides insights for structuring evaluations of prototype input devices.

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2006-15: Utilizing optical sensors from mice for new input devices
by Peter Schneider-Kamp 05 Dec '06

05 Dec '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Utilizing optical sensors from mice for new input devices Sebastian Ullrich, Jakob T. Valvoda, Torsten Kuhlen AIB 2006-15 This paper introduces approaches towards the development of intuitive input devices built with optical sensors from mice. The two main ideas are spatial reconfiguration of the sensor and advanced interpretation of the sensor data. We present new concepts for various input devices that are easy to rebuild. A prototype for kinematics manipulation of virtual characters has been constructed and algorithms for data interpretation have been implemented and evaluated.

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2006-13: Unranked Tree Automata with Sibling Equalities and Disequalities
by Peter Schneider-Kamp 22 Nov '06

22 Nov '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Unranked Tree Automata with Sibling Equalities and Disequalities Wong Karianto, Christof Löding AIB 2006-13 We propose an extension of the tree automata with constraints between direct subtrees (Bogaert and Tison, 1992) to unranked trees. Our approach uses MSO-formulas to capture the possibility of comparing unboundedly many direct subtrees. Our main result is that the nonemptiness problem for the deterministic automata, as in the ranked setting, is decidable. It turns out that the main difficulty is indeed the absence of the rank, as it gives a certain bound on the number of distinct subtrees needed in order to satisfy an equality or disequality constraint. We overcome this difficulty by finding such a bound via a brute-force method. Keywords: (unranked) tree automata, monadic second-order logic, equality and disequality constraints

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2006-14: Report of the GI Work Group "Requirements Management Tools for Product Line Engineering"
by Peter Schneider-Kamp 14 Nov '06

14 Nov '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Report of the GI Work Group "Requirements Management Tools for Product Line Engineering" Danilo Beuche, Andreas Birk, Heinrich Dreier, Andreas Fleischmann, Heidi Galle, Gerald Heller, Dirk Janzen, Isabel John, Ramin Tavakoli Kolagari, Thomas von der Maßen, Andreas Wolfram AIB 2006-14 A software product-line-oriented approach to developing systems has an impact on the development process as a whole. All artifacts produced during the process have to be properly managed in order to benefit from a product-line-oriented approach. Although the basic idea of product lines is simple, systematic implementation of the approach is a challenging task. In fact, today's software system families have such complex variability that their handling must be supported by tools, otherwise a systematic approach would not be possible. The same holds for requirements management of software product lines. The technical report presented here analyzes specific scenarios in the context of requirements management and software product lines and derives important requirements that have to be observed if requirements management tools are to be usefully applied to product lines. Current requirements management tools are evaluated on the basis of these requirements. This evaluation revealed that all requirements management tools currently used in industry need to be improved if they are to be successfully used in a product line setting. Nevertheless these tools are used in practice and are also used in product line settings and as the scenarios described in this report show they are also used successfully - but this is only achieved because workarounds are in place: either the tool itself is enhanced or related processes bypass shortcomings of the tool. The result of this report is a comprehensive analysis of requirements and requirements management tools in the context of software product lines based on practical experience.

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2006-12: Replaying Play in and Play out: Synthesis of Design Models from Scenarios by Learning
by Peter Schneider-Kamp 26 Oct '06

26 Oct '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Replaying Play in and Play out: Synthesis of Design Models from Scenarios by Learning Benedikt Bollig, Joost-Pieter Katoen, Carsten Kern, Martin Leucker AIB 2006-12 This paper is concerned with bridging the gap between requirements, provided as a set of scenarios, and conforming design models. The novel aspect of our approach is to exploit learning for the synthesis of design models. In particular, we present a procedure that infers a message-passing automaton (MPA) from a given set of positive and negative scenarios of the system's behavior provided as message sequence charts (MSCs). The paper investigates which classes of regular MSC languages and corresponding MPAs can (not) be learned, and presents a dedicated tool based on the learning library LearnLib that supports our approach.

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2006-05: Adjoint Code by Source Transformation with OpenAD/F
by Peter Schneider-Kamp 26 Sep '06

26 Sep '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Adjoint Code by Source Transformation with OpenAD/F Uwe Naumann, Jean Utke, Patrick Heimbach, Chris Hill, Derya Ozyurt, Carl Wunsch, Mike Fagan, Nathan Tallent, Michelle Strout AIB 2006-05 This document reports on recent advances in the development of the adjoint code generator OpenAD/F. We give an overview of the software design, and we discuss case studies that illustrate the feasibility of adjoint code generation. Our main target application is the MIT General Circulation Model --- a numerical model designed for study of the atmosphere, ocean, and climate.

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2006-09: Counterexamples in Probabilistic Model Checking
by Peter Schneider-Kamp 11 Sep '06

11 Sep '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Counterexamples in Probabilistic Model Checking Tingting Han, Joost-Pieter Katoen AIB 2006-09 This paper considers algorithms and complexity results for the generation of counterexamples in model checking of probabilistic until-formulae in discrete-time Markov chains (DTMCs). It is shown that finding the strongest evidence (i.e, the most probable path) that violates a (bounded) until-formula can be found in polynomial time using single-source (hop-constrained) shortest path algorithms. We also show that computing the smallest counterexample that is mostly deviating from the required probability bound can be found in a pseudo-polynomial time complexity by adopting a certain class of algorithms for the (hop-constrained) $k$ shortest paths problem.

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2006-11: Model Checking Software for Microcontrollers
by Peter Schneider-Kamp 07 Sep '06

07 Sep '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: Model Checking Software for Microcontrollers Bastian Schlich, Michael Rohrbach, Michael Weber, Stefan Kowalewski AIB 2006-11 A method for model checking of microcontroller code is presented. The main objective is to check embedded C code including typical hardware specific ingredients like embedded assembly statements, direct memory accesses, direct register accesses, interrupts, and timers, without any further manual preprocessing. For this purpose, the state space is generated directly from the assembly code that is generated from C code for the specific microcontroller, in our case the ATMEL ATmega family. The properties to be checked can refer to the global C variables as well as to the microcontroller registers and the SRAM. By this approach we are able to find bugs which cannot be found if one looks at the C code or the assembly code alone. The paper explains the basic functionality of our tools using two illustrative examples.

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2006-10: From Simulations to Testbeds - Architecture of the Hybrid MCG-Mesh Testbed
by Peter Schneider-Kamp 15 Aug '06

15 Aug '06

The following technical report is available from http://aib.informatik.rwth-aachen.de: >From Simulations to Testbeds - Architecture of the Hybrid MCG-Mesh Testbed Mesut Günes, Alexander Zimmermann, Martin Wenig, Jan Ritzerfeld, Ulrich Meis AIB 2006-10 The study of wireless and mobile networks is mainly based on simulations. According to recent publications 76% of the studies in this area are based on simulations. Although simulation environments offer a convenient combination of flexibility and controllability, their largest disadvantage is that the results gained by using them are difficult to transfer into reality. This is due to the complex environment of mobile and wireless networks. In this paper we introduce a hybrid testbed approach, which consists of real mesh nodes and a virtualization environment. This combination provides on the one hand a flexible development environment for distributed network protocols and applications, and on the other hand a high degree of realism. Therefore, it allows the design and evaluation of large scale networks where the results are easily transferred to the real world.

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