Publications by Christina Fragouli

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

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

Creating Secrets Out Of Packet Erasures

Christina Fragouli, Aikaterini Argyraki, Iris Safaka, László Czap

We present protocols for creating pairwise secrets between nodes in a wireless network, so that these secrets are secure from an eavesdropper, Eve, with unbounded computational and memory capabilities, but with limited network presence. We first present a ...

Ieee-Inst Electrical Electronics Engineers Inc2016

An LP Characterization of the Secret-message Capacity of Three Erasure Networks With Feedback

Suhas Diggavi, Christina Fragouli, László Czap, Vinod Malathidevi Prabhakaran

This paper presents exact capacity characterizations for the case, when a principal, Alice, wants to securely send a message to another principal, Bob, over three network configurations: the parallel edges network, the V-network, and the triangle network. ...

Ieee-Inst Electrical Electronics Engineers Inc2016

MicroCast: Cooperative Video Streaming Using Cellular and Local Connections

Lorenzo Keller, Christina Fragouli

We consider a group of mobile users, within proximity of each other, who are interested in watching the same online video. The common practice today is that each user downloads the video independently on her mobile device using her own cellular connection, ...

Ieee-Inst Electrical Electronics Engineers Inc2016

On the Complexity of Scheduling in Half-Duplex Diamond Networks

Christina Fragouli, Ayfer Özgür Aydin, Siddhartha Brahma

We consider an n-relay Gaussian diamond network where a source communicates to a destination with the help of n half-duplex relays. Achieving rates close to the capacity of this network requires to employ all the n relays under an optimal transmit/receive ...

Ieee-Inst Electrical Electronics Engineers Inc2016

Matryoshka: Hiding Secret Communication in Plain Sight

Christina Fragouli, Aikaterini Argyraki, Iris Safaka

We want to enable a pair of communicating users to exchange secret messages while hiding the fact that secret communication is taking place. We propose a linguistic steganography approach, where each human message is hidden in another human-like message. A ...

2016

System and method for cooperative data streaming

Lorenzo Keller, Christina Fragouli

A system and method for cooperative data streaming are disclosed. According to one embodiment, a system for cooperative data streaming comprises a group of devices comprising at least two devices, which are interested in obtaining the same content from the ...

2015

Secure Network Coding With Erasures and Feedback

Suhas Diggavi, Christina Fragouli, László Czap, Vinod Malathidevi Prabhakaran

Secure network coding assumes that the underlying network channels are error-free; thus, if our channels introduce errors, we need to first apply a channel code to correct them, and then build security on top of the resulting error-free network. In this pa ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Secret Communication Over Broadcast Erasure Channels With State-Feedback

Suhas Diggavi, Christina Fragouli, László Czap, Vinod Malathidevi Prabhakaran

We consider a 1-to-K communication scenario, where a source transmits private messages to K receivers through a broadcast erasure channel, and the receivers feedback strictly, causally, and publicly their channel states after each transmission. We explore ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Pliable Index Coding

Christina Fragouli, Siddhartha Brahma

We formulate a new variant of the index coding problem, where instead of demanding a specific message, clients are pliable, and are interested in receiving any t messages that they do not have. We term this problem pliable index coding or PICOD(t). We prov ...

Ieee-Inst Electrical Electronics Engineers Inc2015

A simple relaying strategy for diamond networks

Christina Fragouli, Siddhartha Brahma

We consider a Gaussian diamond network where a source communicates with the destination through n non-interfering half-duplex relays. Using simple approximations to the capacity of the network, we show that simple relaying strategies involving two relays a ...

Ieee2014

Triangle Network Secrecy

Suhas Diggavi, Christina Fragouli, László Czap, Vinod Malathidevi Prabhakaran

We characterize the secret message capacity of the triangle network, that consists of a source, a relay and a destination connected through orthogonal erasure channels. A passive eavesdropper, Eve, wiretaps any one of the three channels. The source and the ...

2014

System and method for local multiplayer gaming

Lorenzo Keller, Christina Fragouli

A system and method for local multiplayer gaming are disclosed. According to one embodiment, a system comprises a plurality of mobile client devices including a mobile client device designated as a server device. Each mobile client device comprises a displ ...

2014

Cooperative Relaying at Finite SNR-Role of Quantize-Map-and-Forward

Christina Fragouli, Ayan Sengupta, I-Hsiang Wang

This paper contributes to the design and analysis of Quantize-Map-and-Forward (QMF) relaying by optimizing its performance for small relay networks. QMF was proved to achieve the capacity of arbitrary networks within a bounded gap, as well as the optimal d ...

Ieee-Inst Electrical Electronics Engineers Inc2014

Wireless Network Simplification: The Gaussian N-Relay Diamond Network

Christina Fragouli

We consider the Gaussian N-relay diamond network, where a source wants to communicate to destination node through a layer of N-relay nodes. We investigate the following question: what fraction of the capacity can we maintain using only k out of the N avail ...

Institute of Electrical and Electronics Engineers2014

Efficient Subnetwork Selection in Relay Networks

Christina Fragouli, Ayan Sengupta, Siddhartha Brahma

We consider a source that would like to communicate with a destination over a layered Gaussian relay network. We present a computationally efficient method that enables to select a near-optimal (in terms of throughput) subnetwork of a given size connecting ...

Ieee2014

Structure of optimal schedules in diamond networks

Christina Fragouli, Siddhartha Brahma

We consider Gaussian diamond networks with n half-duplex relays. At any point of time, a relay can either be in a listening (L) or transmitting (T) state. The capacity of such networks can be approximated to within a constant gap (independent of channel SN ...

Ieee2014

A Network Coding Approach to Loss Tomography

Christina Fragouli

Network tomography aims at inferring internal network characteristics based on measurements at the edge of the network. In loss tomography, in particular, the characteristic of interest is the loss rate of individual links and multicast and/or unicast end- ...

Institute of Electrical and Electronics Engineers2013

Creating Secrets out of Erasures

Suhas Diggavi, Christina Fragouli, Aikaterini Argyraki, Panagiotis Kostopoulos

Current security systems often rely on the adversary's computational limitations. Wireless networks offer the opportunity for a different, complementary kind of security, which relies on the adversary's limited network presence (i.e., that the adversary ca ...

2013