Democratic Fair Allocation of Indivisible Goods

We study the problem of fairly allocating indivisible goods to groups of agents. Agents in the same group share the same set of goods even though they may have different preferences. Previous work has focused on unanimous fairness, in which all agents in each group must agree that their group's share is fair. Under this strict requirement, fair allocations exist only for small groups. We introduce the concept of democratic fairness, which aims to satisfy a certain fraction of the agents in each group. This concept is better suited to large groups such as cities or countries. We present protocols for democratic fair allocation among two or more arbitrarily large groups of agents with monotonic, additive, or binary valuations. For two groups with arbitrary monotonic valuations, we give an efficient protocol that guarantees envy-freeness up to one good for at least $1/2$ of the agents in each group, and prove that the $1/2$ fraction is optimal. We also present other protocols that make weaker fairness guarantees to more agents in each group, or to more groups. Our protocols combine techniques from different fields, including combinatorial game theory, cake cutting, and voting.Comment: Appears in the 27th International Joint Conference on Artificial Intelligence and the 23rd European Conference on Artificial Intelligence (IJCAI-ECAI), 201

Redividing the Cake

A heterogeneous resource, such as a land-estate, is already divided among several agents in an unfair way. It should be re-divided among the agents in a way that balances fairness with ownership rights. We present re-division protocols that attain various trade-off points between fairness and ownership rights, in various settings differing in the geometric constraints on the allotments: (a) no geometric constraints; (b) connectivity --- the cake is a one-dimensional interval and each piece must be a contiguous interval; (c) rectangularity --- the cake is a two-dimensional rectangle or rectilinear polygon and the pieces should be rectangles; (d) convexity --- the cake is a two-dimensional convex polygon and the pieces should be convex. Our re-division protocols have implications on another problem: the price-of-fairness --- the loss of social welfare caused by fairness requirements. Each protocol implies an upper bound on the price-of-fairness with the respective geometric constraints.Comment: Extended IJCAI 2018 version. Previous name: "How to Re-Divide a Cake Fairly

The invisible power of fairness. How machine learning shapes democracy

Many machine learning systems make extensive use of large amounts of data regarding human behaviors. Several researchers have found various discriminatory practices related to the use of human-related machine learning systems, for example in the field of criminal justice, credit scoring and advertising. Fair machine learning is therefore emerging as a new field of study to mitigate biases that are inadvertently incorporated into algorithms. Data scientists and computer engineers are making various efforts to provide definitions of fairness. In this paper, we provide an overview of the most widespread definitions of fairness in the field of machine learning, arguing that the ideas highlighting each formalization are closely related to different ideas of justice and to different interpretations of democracy embedded in our culture. This work intends to analyze the definitions of fairness that have been proposed to date to interpret the underlying criteria and to relate them to different ideas of democracy.Comment: 12 pages, 1 figure, preprint version, submitted to The 32nd Canadian Conference on Artificial Intelligence that will take place in Kingston, Ontario, May 28 to May 31, 201

Good Governance: A Framework for Implementing Sustainable Land Management, Applied to an Agricultural Case in Northeast-Brazil

Land management needs to cope with persistent environmental and societal changes. This requires functional governance systems. The purpose of this research is to develop a good governance framework for the implementation of sustainable land management. Good governance theory is extensive, although its operationalization remains difficult. We derived a set of good governance attributes from the literature: (i) the functionality of the regulatory framework, (ii) the legitimacy and accountability of the actors, (iii) the fairness and transparency of the decision-making processes, and (iv) quality control and adaptiveness. These constitute a framework which, supported by guiding questions, facilitates the evaluation of governance attributes to assess sustainable land management practices. We applied the scheme to a case study in Northeast Brazil regarding sustainable land management where biological pest control is considered to be a biodiversity-related ecosystem service. Since its adoption often falls short of expectations, we scrutinized its governance system. First, experts answered our guiding questions, and second, we involved local stakeholders in the discussion of good governance attributes through the participatory approach of constellation analysis. Trust in agricultural consultants and issues of the practical application of pest control turned out to be crucial. The workshop participants requested a model farm to build more trust and experience. There was considerable demand for policy at the national planning level to formulate and monitor the content of the agricultural advisory program. Our conceptualized framework of good governance questions provides systematization for planning and steering the implementation of sustainable land management practices.BMBF, 01LL0904A, Verbundvorhaben INNOVATE: Nachhaltige Nutzung von Stauseen durch innovative Kopplung von aquatischen und terrestrischen Ökosystemfunktionen - Teilvorhaben 1: Verbundkoordination, Grüne Leber und ÖkonomieBMBF, 01LL0904E, Verbundvorhaben INNOVATE: Nachhaltige Nutzung von Stauseen durch innovative Kopplung von aquatischen und terrestrischen Ökosystemfunktionen - Teilvorhaben 5: BiodiversitätDFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

Recommender systems and their ethical challenges

This article presents the first, systematic analysis of the ethical challenges posed by recommender systems through a literature review. The article identifies six areas of concern, and maps them onto a proposed taxonomy of different kinds of ethical impact. The analysis uncovers a gap in the literature: currently user-centred approaches do not consider the interests of a variety of other stakeholders—as opposed to just the receivers of a recommendation—in assessing the ethical impacts of a recommender system