12 research outputs found
Implicit Coordination of Caches in Small Cell Networks under Unknown Popularity Profiles
We focus on a dense cellular network, in which a limited-size cache is
available at every Base Station (BS). In order to optimize the overall
performance of the system in such scenario, where a significant fraction of the
users is covered by several BSs, a tight coordination among nearby caches is
needed. To this end, this pape introduces a class of simple and fully
distributed caching policies, which require neither direct communication among
BSs, nor a priori knowledge of content popularity. Furthermore, we propose a
novel approximate analytical methodology to assess the performance of
interacting caches under such policies. Our approach builds upon the well known
characteristic time approximation and provides predictions that are
surprisingly accurate (hardly distinguishable from the simulations) in most of
the scenarios. Both synthetic and trace-driven results show that the our
caching policies achieve excellent performance (in some cases provably
optimal). They outperform state-of-the-art dynamic policies for interacting
caches, and, in some cases, also the greedy content placement, which is known
to be the best performing polynomial algorithm under static and perfectly-known
content popularity profiles
Similarity Caching: Theory and Algorithms
This paper focuses on similarity caching systems, in which a user request for an object o that is not in the cache can be (partially) satisfied by a similar stored object o 0 , at the cost of a loss of user utility. Similarity caching systems can be effectively employed in several application areas, like multimedia retrieval, recommender systems, genome study, and machine learning training/serving. However, despite their relevance, the behavior of such systems is far from being well understood. In this paper, we provide a first comprehensive analysis of similarity caching in the offline, adversarial, and stochastic settings. We show that similarity caching raises significant new challenges, for which we propose the first dynamic policies with some optimality guarantees. We evaluate the performance of our schemes under both synthetic and real request traces
Online Caching with no Regret: Optimistic Learning via Recommendations
The design of effective online caching policies is an increasingly important
problem for content distribution networks, online social networks and edge
computing services, among other areas. This paper proposes a new algorithmic
toolbox for tackling this problem through the lens of optimistic online
learning. We build upon the Follow-the-Regularized-Leader (FTRL) framework,
which is developed further here to include predictions for the file requests,
and we design online caching algorithms for bipartite networks with fixed-size
caches or elastic leased caches subject to time-average budget constraints. The
predictions are provided by a content recommendation system that influences the
users viewing activity and hence can naturally reduce the caching network's
uncertainty about future requests. We also extend the framework to learn and
utilize the best request predictor in cases where many are available. We prove
that the proposed {optimistic} learning caching policies can achieve sub-zero
performance loss (regret) for perfect predictions, and maintain the sub-linear
regret bound , which is the best achievable bound for policies that
do not use predictions, even for arbitrary-bad predictions. The performance of
the proposed algorithms is evaluated with detailed trace-driven numerical
tests.Comment: arXiv admin note: substantial text overlap with arXiv:2202.1059
Similarity Caching: Theory and Algorithms
International audienceThis paper focuses on similarity caching systems, in which a user request for an object o that is not in the cache can be (partially) satisfied by a similar stored object o , at the cost of a loss of user utility. Similarity caching systems can be effectively employed in several application areas, like multimedia retrieval, recommender systems, genome study, and machine learning training/serving. However, despite their relevance, the behavior of such systems is far from being well understood. In this paper, we provide a first comprehensive analysis of similarity caching in the offline, adversarial, and stochastic settings. We show that similarity caching raises significant new challenges, for which we propose the first dynamic policies with some optimality guarantees. We evaluate the performance of our schemes under both synthetic and real request traces