NEGLIA , Giovanni

In this paper, we initiate the study of local model reconstruction attacks for federated learning, where a honest-but-curious adversary eavesdrops the messages exchanged between the client and the server and reconstructs the local model of the client. The success of this attack enables better performance of other known attacks, such as the...

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 paper introduces a...

k-Nearest Neighbors aims at efficiently finding items close to a query in a large collection of objects, and it is used in different applications, from image retrieval to recommendation. These applications achieve high throughput combining two different elements: 1) approximate nearest neighbours searches that reduce the complexity at the cost...

In this paper we study online caching problems where predictions of future requests, e.g., provided by a machine learning model, are available. We consider different optimistic caching policies which are based on the Follow-The-Regularized-Leader algorithm and enjoy strong theoretical guarantees in terms of regret. These new policies have a...

The Miss Ratio Curve (MRC) represents a fundamental tool for cache performance profiling. Approximate methods based on sampling provide a low-complexity solution for MRC construction. Nevertheless, in this paper we show that, in case of content with a large variance in popularity, the approximate MRC may be highly sensitive to the set of...

Commonly used caching policies, such as LRU (Least Recently Used) or LFU (Least Frequently Used), exhibit optimal performance only under specific traffic patterns. Even advanced machine learning-based methods, which detect patterns in historical request data, struggle when future requests deviate from past trends. Recently, a new class of...

Demand-Response (DR) programs, whereby users of an electricity network are encouraged by economic incentives to rearrange their consumption in order to reduce production costs, are envisioned to be a key feature of the smart grid paradigm. Several recent works proposed DR mechanisms and used analytical models to derive optimal incentives. Most...

In this paper we focus on vertex-cut graph partitioning and we investigate how it is possible to evaluate the quality of a partition before running the computation. To this purpose we scrutinize a set of metrics proposed in literature. We carry experiments with the widely-used framework for graph processing Apache GraphX and we perform an...

The most popular framework for distributed training of machine learning models is the (synchronous) parameter server (PS). This paradigm consists of n workers, which iteratively compute updates of the model parameters, and a stateful PS, which waits and aggregates all updates to generate a new estimate of model parameters and sends it back to...

In cross-device federated learning (FL) setting, clients such as mobiles cooperate with the server to train a global machine learning model, while maintaining their data locally. However, recent work shows that client's private information can still be disclosed to an adversary who just eavesdrops the messages exchanged between the client and...

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 , 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,...

The most popular framework for distributed training of machine learning models is the (synchronous) parameter server (PS). This paradigm consists of n workers, which iteratively compute updates of the model parameters, and a stateful PS, which waits and aggregates all updates to generate a new estimate of model parameters and sends it back to...

We consider in-memory key-value stores used as caches, and their elastic provisioning in the cloud. The cost associated to such caches not only includes the storage cost, but also the cost due to misses: in fact, the cache miss ratio has a direct impact on the performance perceived by end users, and this directly affects the overall revenues...

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', 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,...

Deploying graph on a cluster requires its partitioning into a number of subgraphs, and assigning them to different machines. Two partitioning approaches have been proposed: vertex partitioning and edge partitioning. In the edge partitioning approach edges are allocated to partitions. Recent studies show that, for power-law graphs, edge...

In distributed graph computation, graph partitioning is an important preliminary step, because the computation time can significantly depend on how the graph has been split among the different executors. In this paper, we propose a framework for distributed edge partitioning based on simulated annealing. The framework can be used to optimize a...

In distributed graph computation, graph partitioning is an important preliminarystep, because the computation time can significantly depend on how the graph has been split amongthe different executors. In this paper, we propose a framework for distributed edge partitioningbased on simulated annealing. The framework can be used to optimize a...

We propose a caching policy that uses a feedforward neural network (FNN) to predict content popularity. Our scheme outperforms popular eviction policies like LRU or ARC, but also a new policy relying on the more complex recurrent neural networks. At the same time, replacing the FNN predictor with a naive linear estimator does not degrade...

The most popular framework for parallel training of machine learning models is the (synchronous) parameter server (PS). This paradigm consists of n workers and a stateful PS, which waits for the responses of every worker's computation to proceed to the next iteration. Transient computation slowdowns or transmission delays can intolerably...

We consider elastic resource provisioning in the cloud, focusing on in-memory key-value stores used as caches. Our goal is to dynamically scale resources to the traffic pattern minimizing the overall cost, which includes not only the storage cost, but also the cost due to misses. In fact, a small variation of the cache miss ratio may have a...

Similarity caching systems have recently attracted the attention of the scientific community, as they can be profitably used in many application contexts, like multimedia retrieval, advertising, object recognition, recommender systems and online content-match applications. In such systems, a user request for an object , which is not in the...

Network growth models that embody principles such as preferential attachment and local attachment rules have received much attention over the last decade. Among various approaches, random walks have been leveraged to capture such principles. In this paper we consider the No Restart Random Walk (NRRW) model where a walker builds its graph (tree)...

Cache policies to minimize the content retrieval cost have been studied through competitive analysis when the miss costs are additive and the sequence of content requests is arbitrary. More recently, a cache utility maximization problem has been introduced, where contents have stationary popularities and utilities are strictly concave in the...

Cache policies to minimize the content retrieval cost have been studied through competitive analysis when the miss costs are additive and the sequence of content requests is arbitrary. More recently, a cache utility maximization problem has been introduced, where contents have stationary popular-ities and utilities are strictly concave in the...

O tempo que usuários passam nas redes sociais é um tema em voga. A retenção das redes sociais tem importantes implicaçôs, que extrapolam o campo social atingindo aspectos econômicos, psicológicos e de infraestrutura da rede. Neste artigo, consideramos o problema da determinação da taxa ótima de acesso a uma rede social. Para tal, propomos um...