Aswin Suresh

Mining Effective Strategies for Climate Change Communication

Matthias Grossglauser, Aswin Suresh, Yurui Zhu

With the goal of understanding effective strategies to communicate about climate change, we build interpretable models to rank tweets related to climate change with respect to the engagement they generate. Our models are based on the Bradley-Terry model of pairwise comparison outcomes and use a combination of the tweets’ topic and metadata features to do the ranking. To remove confounding factors related to author popularity and minimise noise, they are trained on pairs of tweets that are from the same author and around the same time period and have a sufficiently large difference in engagement. The models achieve good accuracy on a held-out set of pairs. We show that we can interpret the parameters of the trained model to identify the topic and metadata features that contribute to high engagement. Among other observations, we see that topics related to climate projections, human cost and deaths tend to have low engagement while those related to mitigation and adaptation strategies have high engagement. We hope the insights gained from this study will help craft effective climate communication to promote engagement, thereby lending strength to efforts to tackle climate change.

2023

War of Words II: Enriched Models of Law-Making Processes

Matthias Grossglauser, Victor Kristof, Aswin Suresh, Patrick Thiran

The European Union law-making process is an instance of a peer- production system. We mine a rich dataset of law edits and intro- duce models predicting their adoption by parliamentary committees. Edits are proposed by parliamentarians, and they can be in conflict with edits of other parliamentarians and with the original proposition in the law. Our models combine three different categories of features: (a) Explicit features extracted from data related to the edits, the parliamentarians, and the laws, (b) latent features that capture bi-linear interactions between parliamentarians and laws, and (c) text features of the edits. We show experimentally that this combination enables us to accurately predict the success of the edits. Furthermore, it leads to model parameters that are interpretable, hence provides valuable insight into the law-making process.

ACM2021

Load Balancing Video Clients in Enterprise Wireless Networks

Lorenzo Granai, Sergio Mena, Aswin Suresh, Dan-Cristian Tomozei

Given the increasing popularity of real-time video communication over enterprise wireless networks, ensuring good quality of experience is becoming critical. A common problem in such networks is that the clients typically adopt the strategy of associating to the access point with the highest signal strength, which can lead to load imbalance, unfair throughput allocation, and low overall video quality. In this paper, we propose to improve load balancing across video clients by selectively triggering directed roams of chosen clients, while explicitly accounting for the cost of roaming. We formulate the problem of identifying the directed roams to perform as an optimization problem where the objective function reflects both the overall utility of all video clients and the cost due to roaming. We subsequently apply relaxations to the original NP-Hard problem, and propose a three-stage algorithm that efficiently computes an approximate solution. Simulations show that by selectively roaming just 5% of the clients, we increase throughput relative to an initial strongest signal based association by at least 10% for over half of the clients and by at least 20% for over a quarter of the clients. We also increase aggregate throughput, improve fairness and thereby increase the overall video quality.

IEEE2018

Cyber-attack on Packet-Based Time Synchronization Protocols: the Undetectable Delay Box

Sergio Barreto Andrade, Jean-Yves Le Boudec, Aswin Suresh

We present a cyber-attack on packet-based time synchronization protocols (PBTSP) with high-accuracy requirements. The cyber-attack is undetectable from the PBTSP's perspective and exploits a vulnerability that is in the nature of all PBTSPs. It can be successfully performed regardless of the cryptographic protocol that the PBTSP is protected with and it is undetectable by the clock-servo algorithm inside the target slave clock. To perform this cyber-attack, we built a "Delay Box" capable of advancing or delaying a slave clock by introducing a malicious offset of a few microseconds. We run experimental tests to the delay box to prove the magnitude of the attack and to confirm undetectability. We discuss possible countermeasures for this type of attack.

Ieee2016