Personne

Pavlos Nikolopoulos

Publications associées (14)

Edge Caching as Differentiation

Aikaterini Argyraki, Pavlos Nikolopoulos, Muhammad Abdullah

Consider an end-user accessing two content providers, A and B, of the same type. If the end-user's ISP prioritizes A-traffic over B-traffic, the end-user may experience A-content with significantly better quality, and the ISP is said to apply "traffic diff ...

ACM2025

Improving Group Testing via Gradient Descent

Pavlos Nikolopoulos

We study the problem of group testing with non-identical, independent priors. So far, the pooling strategies that have been proposed in the literature take the following approach: a hand-crafted test design along with a decoding strategy is proposed, and g ...

2024

Flow/Path Performance Consistency

Aikaterini Argyraki, Pavlos Nikolopoulos, Georgia Fragkouli

We explore a new network-performance metric: flow/path consistency, which captures whether the end-to-end performance of the flows that traverse a network is consistent with the aggregate performance of the network's elements. We propose a formal definitio ...

ACM2024

Dynamic Group Testing to Control and Monitor Disease Progression in a Population

Pavlos Nikolopoulos

Proactive testing and interventions are crucial for disease containment during a pandemic until widespread vaccination is achieved. However, a key challenge remains: Can we accurately identify all new daily infections with only a fraction of tests needed c ...

2024

Caching and Neutrality

Aikaterini Argyraki, Pavlos Nikolopoulos, Muhammad Abdullah

We are used to defining network neutrality as absence of traffic differentiation, like policing or shaping. These mechanisms, however, are often not what determines end-users’ quality of experience (QoE). Most content today is accessed through edge caches, ...

ACM Association for Computing Machinery2023

Localizing Traffic Differentiation

Aikaterini Argyraki, Pavlos Nikolopoulos, Zeinab Shmeis, Muhammad Abdullah

Network neutrality is important for users, content providers, policymakers, and regulators interested in understanding how network providers differentiate performance. When determining whether a network differentiates against certain traffic, it is importa ...

2023

Community-Aware Group Testing

Suhas Diggavi, Christina Fragouli, Pavlos Nikolopoulos, Sundara Rajan Srinivasavaradhan

Group testing is a technique that can reduce the number of tests needed to identify infected members in a population, by pooling together multiple diagnostic samples. Despite the variety and importance of prior results, traditional work on group testing ha ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Improving Group Testing Via Gradient Descent

Pavlos Nikolopoulos

We study the problem of group testing with nonidentical, independent priors. So far, the pooling strategies that have been proposed in the literature take the following approach: a hand-crafted test design along with a decoding strategy is proposed, and gu ...

IEEE2022

Dynamic Group Testing to Control and Monitor Disease Progression in a Population

Pavlos Nikolopoulos

In this paper, we introduce a "discrete-time SIR stochastic block model" that also allows for group testing and interventions on a daily basis. Our model can be regarded as a discrete version of the well-known continuous-time SIR stochastic network model [ ...

IEEE2022

Group testing for connected communities

Suhas Diggavi, Christina Fragouli, Pavlos Nikolopoulos, Sundara Rajan Srinivasavaradhan

In this paper, we propose algorithms that leverage a known community structure to make group testing more efficient. We consider a population organized in disjoint communities: each individual participates in a community, and its infection probability depe ...

MICROTOME PUBLISHING2021

Group testing for overlapping communities

Pavlos Nikolopoulos

In this paper, we propose algorithms that leverage a known community structure to make group testing more efficient. We consider a population organized in connected communities: each individual participates in one or more communities, and the infection pro ...

IEEE2021

An entropy reduction approach to continual testing

Pavlos Nikolopoulos

SIR (Susceptible, Infected or Recovered) stochastic network models are commonly used to describe the progression of epidemics inside a network. A task of interest in epidemiology is to use these models to estimate the state evolution, both at an individual ...

IEEE2021

Retroactive Packet Sampling for Traffic Receipts

Adrian Perrig, Christos Pappas, Pavlos Nikolopoulos

Is it possible to design a packet-sampling algorithm that prevents the network node that performs the sampling from treating the sampled packets preferentially? We study this problem in the context of designing a "network transparency" system. In this syst ...

ACM2019

Traffic Receipts for Network Transparency

Pavlos Nikolopoulos

Today's Internet is not transparent: when packets get lost or delayed, there is typically no information about where the problem occurred, hence no information about who is responsible. This results in Internet service providers (ISPs) offering service lev ...

EPFL2018