Die Dozenten der Informatik-Institute der Technischen Universität
Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem
Vortrag ein.
Nigel Lovell, Scientia Professor, UNSW Graduate School of Biomedical
Engineering, Sydney, Australia:
Towards Next Generation Bionic Interfaces
Beginn: 04.05.2015, 15:00 Uhr
Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23,
4. OG, Raum 404
Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2015-05-04-lovell.html
Kontakt: Prof. Dr. Reinhold Haux
Many engineering challenges and scientific endeavours are focused on the
interface between physical and biological domains. This presentation will
focus on aspects of the bionic interface where electronic and mechanical
devices interact with biological systems. Descriptions will also cover
aspects of systems interfacing of wearable and implantable devices to
encompass not just medical therapeutic devices but also diagnostic and
physiological monitoring devices.
Two technologies will be considered to illustrate the importance
of the next generation of bionic interfaces. These will include an
implantable device designed to restore aspects of patterned vision to
those with profound vision loss – a so-called ‘bionic eye’ or
visual neuroprosthesis, as well as a wearable ambulatory device with
applications in fall detection and fall prediction.
A critical consideration in designing a visual neuroprosthesis that
affords improved visual acuity is engineering a stable, long-term, low
impedance interface between the stimulating electrodes and the neural
tissue; and associated with this, optimising stimulation paradigms to
provide localised and punctate phosphenes with minimal cross-talk or
interaction between electrodes. Various scientific and technological
advances, including improvements in current steering and electrode
coatings, will be explored.
The next generation of bionic devices will also include implantable
and wearable monitoring technologies. As an example, we will describe
wearable ambulatory technologies based around inertial measurement units
coupled with barometric pressure sensors for estimating risks of falling
and for automatically detecting falls in the free-living environment.
Die Dozenten der Informatik-Institute der Technischen Universität
Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem
Vortrag ein.
Prof. Dr. Roland Meyer, TU Kaiserslautern:
Robustness against Relaxed Memory Models
Beginn: 10.04.2015, 14:00 Uhr
Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23,
1. OG, Hörsaal M 161
Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2015-04-09-glabbeek.html
Kontakt: Prof. Dr.-Ing. Ina Schaefer
For performance reasons, modern multiprocessors implement relaxed memory
consistency models that admit out-of-program-order and non-store atomic
executions. While data race-free programs are not sensitive to these
relaxations, they pose a serious problem to the development of the
underlying concurrency libraries. Library routines that work correctly
under Sequential Consistency (SC) show undesirable effects when run
under a relaxed memory model. These routines are not robust against
the relaxations that the processor supports. To enforce robustness, the
programmer has to add safety net instructions to the code that control
the hardware --- a task that has proven to be difficult, even for experts.
We recently developed algorithms that check and, if necessary, enforce
robustness against prominent relaxed memory models like TSO implemented
in x86 processors and Power implemented in IBM architectures. Given
a program, our algorithms decide whether the actual behavior on the
processor coincides with the SC semantics. If this is not the case, they
synthesize safety net instructions that enforce robustness. When built
into a compiler, our algorithms thus hide the relaxed memory model from
the programmer and provide the illusion of Sequential Consistency. In
this talk, we motivate the robustness problem and explain how to reduce
it to an emptiness problem for a new automaton model.
Die Dozenten der Informatik-Institute der Technischen Universität
Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem
Vortrag ein.
Rob van Glabbeek, NICTA, Sydney, Australien:
CCS, it’s not fair!
Beginn: 09.04.2015, 10:00 Uhr
Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23,
1. OG, Hörsaal M 160
Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2015-04-09-glabbeek.html
Kontakt: Prof. Dr.-Ing. Ina Schaefer
Fair Schedulers cannot be implemented in CCS-like languages even under
progress and certain fairness assumptions. In the process algebra
community it is sometimes suggested that, on some level of abstraction,
any distributed system can be modelled in standard process-algebraic
specification formalisms like CCS. This sentiment is strengthened by
results testifying that CCS, like many similar formalisms, is Turing
powerful and provides a mechanism for interaction. This talk counters
that sentiment by presenting a simple fair scheduler---one that in
suitable variations occurs in many distributed systems---of which no
implementation can be expressed in CCS, unless CCS is enriched with a
fairness assumption. The same could be said for COSY, CSP, ACP, LOTOS,
mCRL, the pi-calculus, etc. A cornerstone in the proof is that the fair
scheduler cannot be implemented in terms of Petri nets.
Since Dekker's and Peterson's mutual exclusion protocols implement fair
schedulers, it follows that these protocols cannot be rendered correctly
in CCS without imposing a fairness assumption. Peterson expressed this
algorithm correctly in pseudocode without resorting to a fairness
assumption, so it furthermore follows that CCS lacks the expressive
power to accurately capture such pseudocode.
Die Dozenten der Informatik-Institute der Technischen Universität
Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem
Vortrag ein.
Prof. Dr. Roland Meyer, TU Kaiserslautern:
Robustness against Relaxed Memory Models
Beginn: 10.04.2015, 14:00 Uhr
Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23,
1. OG, Hörsaal M 161
Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2015-04-09-glabbeek.html
Kontakt: Prof. Dr.-Ing. Ina Schaefer
For performance reasons, modern multiprocessors implement relaxed memory
consistency models that admit out-of-program-order and non-store atomic
executions. While data race-free programs are not sensitive to these
relaxations, they pose a serious problem to the development of the
underlying concurrency libraries. Library routines that work correctly
under Sequential Consistency (SC) show undesirable effects when run
under a relaxed memory model. These routines are not robust against
the relaxations that the processor supports. To enforce robustness, the
programmer has to add safety net instructions to the code that control
the hardware --- a task that has proven to be difficult, even for experts.
We recently developed algorithms that check and, if necessary, enforce
robustness against prominent relaxed memory models like TSO implemented
in x86 processors and Power implemented in IBM architectures. Given
a program, our algorithms decide whether the actual behavior on the
processor coincides with the SC semantics. If this is not the case, they
synthesize safety net instructions that enforce robustness. When built
into a compiler, our algorithms thus hide the relaxed memory model from
the programmer and provide the illusion of Sequential Consistency. In
this talk, we motivate the robustness problem and explain how to reduce
it to an emptiness problem for a new automaton model.
