297,599 research outputs found
Multiwinner Elections with Diversity Constraints
We develop a model of multiwinner elections that combines performance-based
measures of the quality of the committee (such as, e.g., Borda scores of the
committee members) with diversity constraints. Specifically, we assume that the
candidates have certain attributes (such as being a male or a female, being
junior or senior, etc.) and the goal is to elect a committee that, on the one
hand, has as high a score regarding a given performance measure, but that, on
the other hand, meets certain requirements (e.g., of the form "at least
of the committee members are junior candidates and at least are
females"). We analyze the computational complexity of computing winning
committees in this model, obtaining polynomial-time algorithms (exact and
approximate) and NP-hardness results. We focus on several natural classes of
voting rules and diversity constraints.Comment: A short version of this paper appears in the proceedings of AAAI-1
Multiwinner Voting with Fairness Constraints
Multiwinner voting rules are used to select a small representative subset of
candidates or items from a larger set given the preferences of voters. However,
if candidates have sensitive attributes such as gender or ethnicity (when
selecting a committee), or specified types such as political leaning (when
selecting a subset of news items), an algorithm that chooses a subset by
optimizing a multiwinner voting rule may be unbalanced in its selection -- it
may under or over represent a particular gender or political orientation in the
examples above. We introduce an algorithmic framework for multiwinner voting
problems when there is an additional requirement that the selected subset
should be "fair" with respect to a given set of attributes. Our framework
provides the flexibility to (1) specify fairness with respect to multiple,
non-disjoint attributes (e.g., ethnicity and gender) and (2) specify a score
function. We study the computational complexity of this constrained multiwinner
voting problem for monotone and submodular score functions and present several
approximation algorithms and matching hardness of approximation results for
various attribute group structure and types of score functions. We also present
simulations that suggest that adding fairness constraints may not affect the
scores significantly when compared to the unconstrained case.Comment: The conference version of this paper appears in IJCAI-ECAI 201
Neural networks for small scale ORC optimization
This study concerns a thermodynamic and technical optimization of a small scale Organic Rankine Cycle system for waste heat
recovery applications. An Artificial Neural Network (ANN) has been used to develop a thermodynamic model to be used for
the maximization of the production of power while keeping the size of the heat exchangers and hence the cost of the plant at its
minimum. R1234yf has been selected as the working fluid. The results show that the use of ANN is promising in solving complex
nonlinear optimization problems that arise in the field of thermodynamics
Structure in Dichotomous Preferences
Many hard computational social choice problems are known to become tractable
when voters' preferences belong to a restricted domain, such as those of
single-peaked or single-crossing preferences. However, to date, all algorithmic
results of this type have been obtained for the setting where each voter's
preference list is a total order of candidates. The goal of this paper is to
extend this line of research to the setting where voters' preferences are
dichotomous, i.e., each voter approves a subset of candidates and disapproves
the remaining candidates. We propose several analogues of the notions of
single-peaked and single-crossing preferences for dichotomous profiles and
investigate the relationships among them. We then demonstrate that for some of
these notions the respective restricted domains admit efficient algorithms for
computationally hard approval-based multi-winner rules.Comment: A preliminary version appeared in the proceedings of IJCAI 2015, the
International Joint Conference on Artificial Intelligenc
Eco-sustainable routing of power lines for the connection of renewable energy plants to the Italian high-voltage grid
Routing of high-voltage electric transmission lines for the connection of renewable energy-distributed generation plants is a critical issue from an environmental point of view. A standard methodology that accounts for multiple perspectives, influence factors and is able to mediate between weighted constraints can be a useful tool for the regulating bodies that are involved in approval processes. The methodology can be an effective support to increase reliability, save consumers' money and mitigate the unavoidable impacts of the lines on the population living nearby. In this paper we investigate the suitability of a procedure employed by Terna, the Italian high-voltage transmission system operator, to identify the corridors where to route new overhead transmission lines with the lowest environmental impact. The methodology is based on the subdivision of all the relevant constraints dictated by environmental issues and territory legislations in four main classes. A real case study concerning the design and connection of a wind farm placed near Collarmele, in the center of Italy, shows the effectiveness of the proposed methodology
Guidelines for the Provision of Garbage Reception Facilities at Ports Under MARPOL Annex V
This report offers guidelines for the provision of adequate
port reception facilities for vessel-generated garbage
under the requirements of Annex V of the International
Convention for the Prevention of Pollution From Ships, 1973 (MARPOL 73/78), Regulations for the Prevention of Pollution by Garbage from Ships. MARPOL Annex V prohibits at-sea disposal of plastic materials from vessels, and specifies the distance from shore at which other materials may be dumped. Annex V also requires the provision of port reception facilities for garbage, but it does not specify these facilities or how they are to be provided. Since the at-sea dumping restrictions apply to all vessels, the reception facility requirement applies to all ports, terminals, and marinas that serve vessels. These guidelines were prepared to assist port owners and operators in meeting their obligation to provide adequate reception facilities for garbage. The report synthesizes available information and draws upon experience from the first years ofimplementation of MARPOL Annex V. (PDF file contains 55 pages.
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The new Basel accord and developing countries: problems and alternatives
The new Basel Accord framework relies on markets and supervisors to discipline banks. Yet both markets and supervisors fail, and more so in developing countries than in high-income countries. Therefore, the new Accord is not, as its designers claim, suitable for wide application. Nevertheless, developing country policymakers have little choice but to implement it in part or in whole. Hence there are problems of governance in international regulation. I offer seven general principles for the design of a prudential regime more robust to government and market failure. Four alternative capital regimes are evaluated in the light of these principles. Simpler and harsher regimes are likely to achieve greater safety with a given level of resources
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