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The group runs a weekly seminar series, covering papers,
projects, and events related with our research. These seminars
are open to anyone on Chalmers or GU who wishes to attend.
Seminars 2007
Current seminar series coordinator: Daniel Cederman.
| Date | Time | Location | Speaker | Refreshment Organizer | Title + Abstract |
| ti, dec 4 | 10.00 | Sammantr. rum | Anders Blomqvist and Marcus Fredrikson | Andreas | Interactiv Network Visualization
In an analysis of a network the user aims to extract as much
information as possible from the network. The easiest way to
achieve this information is to visualize the network to get
information that is hard to find in other ways. The purpose
with our master thesis, performed at Tibco Software AB
Spotfire Division, was to examine the possibilities and
problems with an implementation of network visualization as an
extension to Spotfire DXP 2.0. By studies of literature within
the subjects of network visualization and by understanding the
architecture behind Spotfire DXP, we created an idea of what
is the most important when it comes to visualization of
network data. The implementation of our Network Visualization
Tool has shown that it is possible to create a network
visualization extension to Spotfire DXP. But there are a few
problems associated with our extension, specifically when it
comes to how to the information handling, that needs to be
resolved before this can be seen as a fully functional
product.
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| ti, dec 11 | 10.00 | Sammantr. rum | Andreas Larsson | Daniel | Travel report from SSS'07
Andreas Larsson will present a travel report from his visit at SSS'07.
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| må, nov 5 | 10.00 | 5453 | Anders Gidenstam | Georgios | Oblivious Routing Schemes[paper]
Anders will present the paper "A Practical Algorithm for Constructing Oblivious Routing Schemes".
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| ti, nov 27 | 10.00 | Sammantr. rum | Anders Gidenstam | Elad | Distributed Approximation Algorithms
Anders Gidenstam will give a talk on a distributed approximation
algorithm for minimum spanning trees by M. Khan and G. Pandurangan
and related results for that and (maybe) similar problems.
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| må, nov 26 | 10.00 | Sammantr. rum | Anders Gidenstam | Lei | Lock-free threads
Anders Gidenstam will give a rehearsal talk of his paper "LFthreads:
A lock-free thread library" that he will present at OPODIS.
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| ti, nov 20 | 10.00 | Sammantr. rum | Georgios Georgiadis | Philippas | Unstructured P2P networks that you can random-walk with ease
In this presentation I will talk about a category of unstructured
P2P networks that can arise in a natural way when people interact,
and their associated emerging properties. In fact, there is no
need for maintaining an complex overlay topology of the network, just
knowledge about the immediate vicinity of a node. Perhaps contrary
to intuition, experimental evidence suggests that these networks
show a lot of nice features, such as navigability by a random walker,
only observed in P2P networks using a more structured overlay
topology. Their governing principles can even be applied to
unstructured P2P networks like the Gnutella network and help
"repair" some inherit flaws such as the flooding problem.
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| ti, nov 13 | 10.00 | Sammantr. rum | Philippas Tsigas | Daniel/Fu | Transactional Memory and Atomicity
Philippas will give a talk on atomicity in the context of transactional memory.
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| ti, okt 30 | 10.00 | Sammantr. rum | Andreas Larsson | Marina | Self-Stabilizing Clock Synchronization
Andreas will give a rehearsal presentation of his paper "Secure and Self-Stabilizing Clock Synchronization in Sensor
Networks". The paper will later be presented at SSS 2007.
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| ti, okt 23 | 10.00 | Sammantr. rum | Lei Zhuang | Andreas | Peer-to-Peer network and protocol verification based on Gnutella
There are four problems and our solutions in the report.
1) Reachability question and Solution in short-circuiting effect
2) Huge redundant messages, engulfing the bandwidth and Connection management
3) 3. Low efficient in Searching and GFB: A system with message feedback mechanism
4) 4. Validity of the network protocols and Formal specification and protocol verification
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| ti, okt 16 | 10.00 | Sammantr. rum | Elad Schiller | Daniel | Highlights from DISC 2007
Elad will give a travel report which will include the highlights of four talks given in
DISC 2007 (Proceedings of the 21st international symposium on
distributed computing).
Efficient Transformations of Obstruction-free Algorithms into
Non-blocking Algorithms
[ppt]
by Gadi Taubenfeld
Gossiping in a Multi-Channel Radio Network
[pdf]
by Shlomi Dolev, Seth Gilbert, Rachid Guerraoui, and Calvin Newport
On the Message Complexity of Indulgent Consensus
[pdf]
by Seth Gilbert, Rachid Guerraoui, and Dariusz Kowalski
Amnesic Distributed Storage
by Gregory Chockler, Rachid Guerraoui, Idit Keidar
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| ti, okt 2 | 10.00 | Sammantr. rum | Daniel Cederman | Fu | Optimizations to the MS-Queue
In this presentation I will talk about the MP/MC queue by Maged Michael and Michael Scott and
show some of the optimizations that can be applied to it.
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| ti, sep 25 | 10.00 | 5453 | Fu Zhang | Georgios | Oblivious data structures
I will present three data structures that have a common property that you
can get no knowledge about the sequence of operations that have been
applied to it other than the final result of the operations. The first
data structure is called Oblivious Tree, a data structure very similar to
2-3 tree , but with the additional property that the only information
conveyed by an Oblivious Tree is the set of values stored at its leaves.
The second on is a hash table based on open addressing, allowing O(1)
insertion and search. The last one is a dynamic perfect hash table that
uses space linear in the number of elements inserted and has expected
amortized insertion and deletion time O(1).
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| ti, sep 18 | 10.00 | Sammantr. rum | Andreas Larsson | Philippas | Experimental evaluation of wireless simulation assumptions[paper]
All analytical and simulation research on ad hoc wireless networks
must necessarily model radio propagation using simplifying assumptions.
Although it is tempting to assume that all radios have circular range,
have perfect coverage in that range, and travel on a two-dimensional plane,
most researchers are increasingly aware of the need to represent more
realistic features, including hills, obstacles,link asymmetries and
unpredictable fading. Although many have noted the complexity of real
radio propagation, and some have quantified the effect of overly simple
assumptions on the simulation of ad hoc network protocols, we provide a
comprehensive review of six assumptions that are still part of many ad hoc
network simulation studies. In particular, we use an extensive set of measurements
from a large outdoor routing experiment to demonstrate the weakness of these
assumptions, and show how these assumptions cause simulation results to
differ significantly from experimental results. We close with a series
of recommendations for researchers, whether they develop protocols,
analytic models, or simulators for adhoc wireless networks.
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| ti, sep 11 | 10.00 | Sammantr. rum | Georgios Georgiadis | Elad | Hierarchies of the Web: How to attack a large, scale-free network[paper]
In this talk, Georgios will discuss the structure of the WWW and
potential threats to it. An introduction to scale-free networks
will be made, and we will see some ways to efficiently attack
(or protect) these networks.
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| må, aug 20 | 10.00 | 5453 | Niklas Elmqvist | Andreas | Visual Graph Exploration using Matrix Representations
In this talk, I will discuss the benefits of adjacency matrix
representations of graphs. We will see some examples of large
graphs---such as the Wikipedia dataset and the HCI citation
database---and how aggregation and powerful interaction techniques can
help us visualize and interact with them effectively.
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| må, aug 13 | 10.00 | 5453 | Daniel Cederman | Daniel | An introduction to CUDA
I will give an overview of CUDA,
NVIDIA's initiative to help programmers perform general purpose computations on
their graphics processors.
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| on, aug 8 | 10.00 | Sammantr. rum | Elad Schiller | - | Game Authority for Robust and Scalable Distributed Selfish-Computer Systems
A joint work with Shlomi Dolev, Paul G. Spirakis, and
Philippas Tsigas. To be presented in PODC 2007.
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| må, jun 18 | 10.00 | Sammantr. rum | Elad Schiller | - | Self-Stabilization Lecture
Workshop Presentation
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| må, jun 11 | 10.00 | 5453 | Philippas Tsigas | - | A Simple, Fast Parallel Implementation of Quicksort and its Performance Evaluation on SUN Enterprise 10000[paper]
We have implemented sample sort and a parallel version of Quicksort on a cache-coherent shared
address space multiprocessor: the SUN ENTERPRISE 10000. Our computational experiments
show that parallel Quicksort outperforms sample sort. Sample sort has been long thought to be
the best, general parallel sorting algorithms, especially for larger data sets.
On 32 processors of the ENTERPRISE 10000 the speedup of parallel Quicksort is more than
six units higher than the speedup of sample sort, resulting in execution times that were more
than 50% faster than sample sort. On one processor parallel quicksort achieved 15% percent
faster execution times than sample sorting. Moreover, because of its low memory requirements,
parallel Quicksort could sort data sets twice the size that sample sort could under the same system
memory restrictions.
The parallel Quicksort algorithm that we implemented is a simple, fine-grain extension of
Quicksort. Although fine-grain parallelism has been thought to be inefficient for computations
like sorting due to the synchronization overheads, we show as part of this work that e?ciency can
be achieved by incorporating non-blocking techniques for sharing data and computation tasks in
the design and implementation of the algorithm. Non-blocking synchronization has increased con-
currency between communication and computation and gives good execution behavior on cache-
coherent shared memory multiprocessor systems. Cache-coherent shared memory multiprocessors
offer fruitful ground for algorithmic or programming techniques that were considered impractical
before, in the context of high-performance programming, to develop and change a little the way
we think about high-performance programming.
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| må, jun 4 | 10.00 | Sammantr. rum | Elad Schiller | - | Self-Stabilization Lecture
Local Stabilization
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| må, maj 7 | 10.00 | Sammantr. rum | Elad Schiller | - | Self-Stabilization Lecture
Convergence in the Presence of Faults
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| fr, apr 27 | 10.00 | 5453 | Aleksandar Despotoski and Marco Passerini | - | Distributed Architectures For Limiting Denial-of-Service Attacks
Denial of Service (DoS) is a type of attack that can be used to compromise the availability of
an Internet service. It is a simple but very effective form of attack, therefore it is a big threat for any
service provider. The attack called Distributed DoS (DDoS) is particularly dangerous: it consists in
a DoS attack where an attacker uses hundreds of hosts to put in the dark a single server. In this
Master Thesis we propose two architectural solutions that have the aim of limiting the effect of
these attacks. Both of the two solutions proposed take advantage of a technique called "port-
hopping" (or "port-hiding"): this technique assumes that the port used for communication is
continuously changed, and a potential attacker does have the knowledge about which one is
currently used. The two architectures are scalable to larger distributed systems where all the
sensitive peers are protected by port-hopping, and, in real life, they could be used for safety critical
services, like systems to handle emergencies. The models described are compared and tested in a
simple configuration to clearly see the trade-offs and qualities of each of them.
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| må, apr 16 | 10.00 | Sammantr. rum | Elad Schiller | - | Self-Stabilization Lecture
Self-Stabilizing Algorithms for Model Conversions
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| må, mar 12 | 10.00 | Sammantr. rum | Marina Papatriantafilou | Philippas | Travel report from DYNAMO
Marina will talk about the DYNAMO
workshop that she participated in.
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| må, mar 5 | 10.00 | Sammantr. rum | Elad Schiller | Daniel | Self-Stabilization Lecture
Motivating Self-Stabilization
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| må, feb 26 | 10.00 | Sammantr. rum | Billy Ho and Kristoffer Karlsson | Andreas | Voice communication through a web browser
This master thesis is about voice communication over the Internet. The
goal was to implement a system that makes voice communication through a
web browser possible.
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| må, feb 12 | 10.00 | Sammantr. rum | Khaja Mohammad Irfan Junedi | Daniel | Routing protocols
A survey and evaluation of routing protocols in mobile ad hoc networks
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| må, feb 5 | 10.00 | Sammantr. rum | Elad Schiller | Elad | Self-Stabilization Lecture
Introduction: Definitions, Techniques, and Paradigms
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| må, jan 29 | 10.00 | Sammantr. rum | Li Wei, Nie Lei and Elad Schiller | Marina | Mobile Ad Hoc Nodes
Elad and students will present a part from
the line of work on mobile ad hoc nodes in
automotive settings. They will start the meeting
by explaining the project as a whole and the
application that they aim at. Then, Li Wei and Nie Lei
will present their recent progress in implementing the project
(about 30min).
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Archived Seminars
Use the following links to get access to the seminar schedules
of previous years:
2008,
2007,
2006,
2005,
2004,
2003,
2002,
2001,
2000.
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