Search Results for author: Guilherme Ramos

Found 7 papers, 0 papers with code

Regulating Group Exposure for Item Providers in Recommendation

no code implementations24 Apr 2022 Mirko Marras, Ludovico Boratto, Guilherme Ramos, Gianni Fenu

Engaging all content providers, including newcomers or minority demographic groups, is crucial for online platforms to keep growing and working.


Robust Reputation Independence in Ranking Systems for Multiple Sensitive Attributes

no code implementations30 Mar 2022 Guilherme Ramos, Ludovico Boratto, Mirko Marras

A notable example is represented by reputation-based ranking systems, a class of systems that rely on users' reputation to generate a non-personalized item-ranking, proved to be biased against certain demographic classes.

Minimum Structural Sensor Placement for Switched Linear Time-Invariant Systems and Unknown Inputs

no code implementations28 Jul 2021 Emily A. Reed, Guilherme Ramos, Paul Bogdan, Sérgio Pequito

First, we provide necessary and sufficient conditions for their structural state and input observability that can be efficiently verified in $O((m(n+p))^2)$, where $n$ is the number of state variables, $p$ is the number of unknown inputs, and $m$ is the number of modes.

A Discrete-time Reputation-based Resilient Consensus Algorithm for Synchronous or Asynchronous Communications

no code implementations1 Jul 2021 Guilherme Ramos, Daniel Silvestre, Carlos Silvestre

Under mild assumptions, we show that: (i) the proposed method converges exponentially to the consensus of the regular agents; (ii) if a regular agent identifies a neighbor as an attacked node, then it is indeed an attacked node; (iii) if the consensus value of the normal nodes differs from that of any of the attacked nodes' values, then the reputation that a regular agent assigns to the attacked neighbors goes to zero.

Equality of Learning Opportunity via Individual Fairness in Personalized Recommendations

no code implementations7 Jun 2020 Mirko Marras, Ludovico Boratto, Guilherme Ramos, Gianni Fenu

To reduce this effect, we propose a novel post-processing approach that balances personalization and equality of recommended opportunities.

Ethics Fairness +2

Reputation (In)dependence in Ranking Systems: Demographics Influence Over Output Disparities

no code implementations25 May 2020 Guilherme Ramos, Ludovico Boratto

In this paper, we formulate the concept of disparate reputation (DR) and study if users characterized by sensitive attributes systematically get a lower reputation, leading to a final ranking that reflects less their preferences.

A Robust Reputation-based Group Ranking System and its Resistance to Bribery

no code implementations13 Apr 2020 Joao Saude, Guilherme Ramos, Ludovico Boratto, Carlos Caleiro

Also, by clustering users, the effect of bribery in the proposed multipartite ranking system is dimmed, comparing to the bipartite case.

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