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.
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.
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.
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
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.
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.
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.
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.
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.
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.