Ciclo de Seminários

Os Seminários PESC têm como objetivo trazer palestras acessíveis a um público mais amplo, ministradas por pesquisadores e professores mais experientes (tanto do PESC como de instituições externas). Ao longo do ano, teremos temas e focos variados, podendo ser mais específicos ou mais abrangentes.

A apresentação e discussão de ideias novas e antigas de diferentes temas contribui de maneira fundamental para a formação e pesquisa desenvolvida por alunos e professores, sendo muitas vezes de interesse de um público mais amplo.

Os Seminários que são on-line ou híbridos ficam gravados no Canal do PESC no YouTube, que apresenta muitas outras gravações importantes sobre o que acontece no PESC.

Próximos Seminários:

Don Towsley, Distinguished University Professor, University of Massachusetts (UMass), Amherst, EUA
14 de setembro às 11h

Resumo - Slides

In this talk we review the versatility of timer driven caches, also known as TTL (time to live) caches. TTL caches are extremely useful, both for designing new cache management policies that can provide differentiated services and as models for classical and new cache replacement policies such as LRU, random, and first in first out. The first part of the talk focuses on the use of TTL caches for providing service differentiation among contents. This relies on the assignment of utilities to content and the use of the utility maximization framework to develop on-line algorithms to maximize the sum of contnet utilities. One of the byproducts of this work is the reverse engineering of classical cache replacement policies as solutions to this cache utilization optimization problem and the identification of the utility functions underlying these policies.

In the second part of the talk we focus on the problem of how cache providers can and should incentivize the services that they provide content providers. We examine two classes of mechanisms that differ according to whether the cache provider charges for the time that the content occupies the cache or the content request rate. In both cases the cache is a TTL cache and the problem that ensues is that of selecting appropriate values for the timers. The conclusion is that a policy that charges according to request rate the latter policy is better suited for providing incentives to the cache provider.

Biografia resumida

Don Towsley holds a B.A. in Physics (1971) and a Ph.D. in Computer Science (1975) from University of Texas. He is currently a Distinguished Professor at the University of Massachusetts in the College of Information & Computer Sciences. He has held visiting positions at numerous universities and research labs. His research interests include networks and performance evaluation.

He is co-founder and Co-EiC of the new ACM Transactions on Modeling and Performance Evaluation of COmputing Systems (TOMPECS), and has served as Editor-in-Chief of IEEE/ACM Transactions on Networking and on numerous editorial boards. He has served as Program Co-chair of several conferences including INFOCOM 2009.

He is a corresponding member of the Brazilian Academy of Sciences and has received several achievement awards including the 2007 IEEE Koji Kobayashi Award and the 2011 INFOCOM Achievement Award. He has received numerous paper awards including the 2012 ACM SIGMETRICS Test-of-Time Award, a 2008 SIGCOMM Test-of-Time Paper Award, and 2015 and 2016 ACM SIGMETRICS Best Paper Awards. Last, he has been elected Fellow of both the ACM and IEEE.

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Ciclo de Seminários

Próximos Seminários:

The Versatility of TTL Caches for cache service differentiation and pricing