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Montresor’s seminar

By stefania | February 22, 2010

Speaker: Alberto Montresor

Date: 2010, February 24

Duration: 55′

Time: 02:30 p.m.

Room: C-29

Title: Gossip in Peer-to-Peer: Beyond dissemination

Abstract:

The gossip paradigm made its first appearance in distributed systems in 1987, when it was applied to disseminate updates in replicated databases. Two decades later, gossip-based protocols have gone far beyond dissemination, solving a large and diverse collection of problems. We believe that the story is not over: while gossip is not the panacea for distributed systems, there are still virgin research areas where it could be profitably exploited. In this talk, we briefly discuss a gossip-based “construction set” for distributed systems and we illustrate how large-scale distributed computing could benefit by the application of its building blocks.

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Capannini’s seminar

By stefania | February 8, 2010

Speaker: Gabriele Capannini

Date: 2010, February, 26

Duration: 55′

Time: 02:30 p.m.

Room: C-29 (Faedo room)

Title:K-Model: A New Computational Model for Stream Processors
Abstract:

We introduce k-model, a computational model to properly evaluate algorithms designed for graphic processors, and other architectures adhering to the stream programming model. We address the lack of one formal complexity model that properly accounts for memory contention, address coalescing in memory accesses, or the serial control of the instruction flows. We study the impact of k-model rules on algorithm design. We devise a coalesced and low contention data access technique for Batcher’s networks, and we evaluate the effectiveness of this technique within our k-model. To evaluate the benefits in using k-model in evaluating solutions for streaming architectures, we compare the complexity of a sorting network built using our technique, and quicksort. Although in theory quicksort is more efficient than bitonic sort, empirically, our bitonic sorting network has been shown to be faster than the state-of-the-art implementation of quicksort on graphics processing units (GPUs). Using our k-model we are able to prove the reason why on GPU architectures this is not true anymore. As a side result, our technique to perform a Batcher’s network on GPUs improves the performance of the fastest comparison-based solution for integers sorting.

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Vahabi’s seminar

By stefania | February 1, 2010

Speaker: Hossein Vahabi

Date: 2010, February 5

Duration: 55′

Time: 03:00 p.m.

Room: C-29 (Faedo room)

Title: Folksonomy

Abstract:

A tag is a free text term, which is assigned to some resources such as a web page. This kind of metadata has been generally created  by a professional or an author of a piece of information for browsing or searching. A new approach is to perform quantitative/qualititative tag analysis of the user-created metadata, which reflects his/her personal point of view for extracting new kind of information. The aim of the seminar is to provide a conceptual model of tagging activities and  to create a user-generated and distributed classification system: Folksonomy.

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De Francisci Morales’ seminar

By stefania | January 18, 2010

Speaker: Gianmarco De Francisci Morales

Date: 2010, January 18

Duration: 50′

Time: 03 p.m.

Room: C-40

Title: How to survive the Data Deluge: Petabyte scale Cloud Computing

Abstract:

Part 1: Introduction
• What, Why and History
Part 2:Technology overview
• Current systems and comparison
Part 3: Research directions
• Ideas for future improvements

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Ceccarelli’s seminar

By stefania | January 14, 2010

Speaker: Diego Ceccarelli

Date: 2010, January 15

Duration: 75′

Time: 10 a.m.

Room: C-29 (Faedo room)

Title: A Dictionary for the efficient research of Biological Pattern

Abstract:

PROSITE is a protein families domains database consisting in significant biological sites expressed through patterns CBG (Classes of characters and Bounded size Gaps).
Given a protein expressed as a sequence of amino acids, we want to know what pattern of the collection are contained within it.
The seminar presents a method to recognize patterns CBG contained in the database whose execution time is not affected by the collection size.
To reach our purpose we use an approach based on bit-parallelism: a technique consisting in take advantage of the “bit to bit” operations inherent parallelism in the machine words.

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Hpc Lab seminar

By stefania | December 15, 2009

Speakers: Hpc Lab members.

Coordinators:

  1. Raffaele Perego
  2. Fabrizio Silvestri
  3. Claudio Lucchese
  4. Ranieri Baraglia
  5. Massimo Coppola

Date: 2009, December 18

Duration: 240′

Time: 02 p.m.

Room: C-29 (Faedo room)

Title: Hpc Lab seminar

Abstract:

  1. introduction slides and new activities and projects presentation;
  2. Web Information Retrieval and Global Computing presentation;
  3. Data Intensive Computing  presentation;
  4. P2P  Area presentation;
  5. Cloud Area presentation.

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Tag-cloud built with titles of recent papers published by HPC Lab people

By raffaele | October 26, 2009

Topics: Research, Uncategorized | No Comments »

Venturini’s seminar

By stefania | September 21, 2009

Speaker: Rossano Venturini

Date: 2009, September 25

Duration: 75′

Time: 11 a.m.

Room: C-29 (Faedo room)

Title: On the bit-complexity of Lempel-Ziv compression

Abstract:
One of the most famous and investigated lossless data-compression
schemes is the one introduced by Lempel and Ziv about 30 years ago.
This compression scheme is known as “dictionary-based
compressor” and consists of squeezing an input string by replacing
some of its substrings with (shorter) codewords which are actually
pointers to a dictionary of phrases built as the string is
processed.

Although many fundamental results are nowadays known about the
speed and effectiveness of this compression process, “we are not
aware of any parsing scheme that achieves optimality when
the LZ77-dictionary is in use under any constraint on the
codewords other than being of equal length”
[N.~Rajpoot and C.~Sahinalp, Handbook of Lossless Data Compression].
Here optimality means to achieve the minimum number of bits in
compressing each individual input string.

In this talk we will show how to obtain LZ77 bit-optimal parsings
efficiently both in time and space.

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SDIA 2010 - Special session of PDP 2010

By stefania | April 16, 2009

SDIA 2010 - Scalable Data Intensive Applications
Special session of the 18th Euromicro Int.l Conf. on Parallel, Distributed and Network-Based Computing - PDP 2010,  February 17-19, 2010 - Pisa, Italy
http://www.pdp2010.org

pdp2010-logoWe are living in the information age. The day-to-day human activities produce overwhelming amount of information, which need be stored in computer-based repositories and warehouses for everyday processing. Storing, managing, sharing, searching, mining, extracting knowledge and aggregating such data for complex applications are thus becoming increasingly more challenging. The size of data and the algorithmic complexity of analysis performed require the exploitation of high-performance parallel and distributed solutions to guarantee scalability and acceptable latency.

This special session will focus on such wide array of scalability issues for data-intensive applications, and investigate new approaches to tackle problems arising from the ever-growing size and complexity of data and information.
Visit for more info http://sdia2010.isti.cnr.it.

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LSDS-IR Workshop at SIGIR 2009

By claudio | April 3, 2009

lsdsir-logo7th Workshop on Large-Scale Distributed Systemsfor Information Retrieval, located at SIGIR 2009. This workshop will provide space for researchers to discuss problems and to define new directions for the work on distributed information retrieval. For more info visit http://lsdsir09.isti.cnr.it/.

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