Hybrid behavioural-based multi-objective space trajectory optimization

In this chapter we present a hybridization of a stochastic based search approach for multi-objective optimization with a deterministic domain decomposition of the solution space. Prior to the presentation of the algorithm we introduce a general formulation of the optimization problem that is suitable to describe both single and multi-objective problems. The stochastic approach, based on behaviorism, combinedwith the decomposition of the solutions pace was tested on a set of standard multi-objective optimization problems and on a simple but representative case of space trajectory design

Just Sort It! A Simple and Effective Approach to Active Preference Learning

We address the problem of learning a ranking by using adaptively chosen pairwise comparisons. Our goal is to recover the ranking accurately but to sample the comparisons sparingly. If all comparison outcomes are consistent with the ranking, the optimal solution is to use an efficient sorting algorithm, such as Quicksort. But how do sorting algorithms behave if some comparison outcomes are inconsistent with the ranking? We give favorable guarantees for Quicksort for the popular Bradley-Terry model, under natural assumptions on the parameters. Furthermore, we empirically demonstrate that sorting algorithms lead to a very simple and effective active learning strategy: repeatedly sort the items. This strategy performs as well as state-of-the-art methods (and much better than random sampling) at a minuscule fraction of the computational cost.Comment: Accepted at ICML 201

A Methodology to Evaluate Accessibility to Bus Stops as a Contribution to Improve Sustainability in Urban Mobility

Walking and transit are the backbone of sustainable mobility. Bus stops not only represent the connection between the two, but are also central in dictating the attractiveness of the latter. Accessibility of bus stops becomes, then, pivotal in increasing both attractiveness and sustainability of public transport. The paper describes a multi-step methodology to evaluate bus stops’ accessibility starting from a cluster of seven indicators describing objective and subjective features influencing passengers’ choice toward a given bus stop. The indicators are weighed by a questionnaire submitted to experts. Finally, a multicriteria analysis is developed to obtain a final score describing univocally the accessibility of each stop. Outcomes are mapped and a case study in Rome is reported as an example, with 231 bus and tram stops assessed accordingly. Results shows the relevance of the urban network and environment in evaluating the accessibility and in promoting more sustainable mobility patterns. Research innovation relies on the possibility to merge data from different fields into a specific GIS map and easily highlight for each bus stop the relationships between built environment, passengers’ comfort, and accessibility, with the concluding goal to provide advanced knowledge for further application

Psychological Stability of Solutions in the Multiple Criteria Decision Problems

In interactive programming, a choice behavior of the decision maker may differ depending on a proximity of current solution to satisfactory values of the objectives. An interactive approach proposed in this paper allows the decision maker to use different search principles depending on his/her perception of the achieved values of the objectives and trade-offs. While an analysis of values of the objectives may guide the initial search for a final solution, it can be replaced by trade-off evaluations at some later stages of interactive decision making. Such an approach allows the decision maker to change search principles, and to identify a psychologically stable solution of the multiple criteria decision problem

Recommended Procedure for Future MODSS in Farm Forestry

This chapter proposes a procedure for future MODSS in farm forestry. It assumes similar limitations as those which applied in the South-east Queensland and the Hodgson Creek study. The most critical constraint was that contact with the stakeholders, especially landholders, was limited to a half-day workshop. A recommended procedure is described, which aims to support and facilitate the decision-making process and maximise community input to support implementation

Exposure Outliers: Children, Mothers, and Cumulative Disaster Exposure in Louisiana

Only a limited number of studies have explored the effects of cumulative disaster exposure—defined here as multiple, acute onset, large-scale collective events that cause disruption for individuals, families, and entire communities. Research that is available indicates that children and adults who experience these potentially traumatic community-level events are at greater risk of a variety of negative health outcomes and ongoing secondary stressors throughout their life course. The present study draws on in-depth interviews with a qualitative subsample of nine mother-child pairs who were identified as both statistical and theoretical outliers in terms of their levels of disaster exposure through their participation in a larger, longitudinal Women and Their Children’s Health (WaTCH) project that was conducted following the British Petroleum Deepwater Horizon Oil Spill. During Wave 2 of the WaTCH study, mothers and their children were asked survey questions about previous exposure to and the impacts of the oil spill, hurricanes, and other disasters. This article presents the qualitative interview data collected from the subsample of children and mothers who both endorsed that they had experienced three or more disasters that had a major impact on the child and the household. We refer to these children as exposure outliers. The in-depth narratives of the four mother-child pairs who told stories of multiple pre-disaster stressors emerging from structural inequalities and health and financial problems, protracted and unstable displacements, and high levels of material and social losses illustrate how problems can pile up to slow or completely hinder individual and family disaster recovery. These four mother-child pairs were especially likely to have experienced devastating losses in Hurricane Katrina in 2005, which then led to an accumulation of disadvantage and ongoing cycles of loss and disruption. The stories of the remaining five mother-child pairs underscore how pre-disaster resources, post-disaster support, and institutional stabilizing forces can accelerate recovery even after multiple disaster exposures. This study offers insights about how families can begin to prepare for a future that is likely to be increasingly punctuated by more frequent and intense extreme weather events and other types of disaster

Matching Code and Law: Achieving Algorithmic Fairness with Optimal Transport

Increasingly, discrimination by algorithms is perceived as a societal and legal problem. As a response, a number of criteria for implementing algorithmic fairness in machine learning have been developed in the literature. This paper proposes the Continuous Fairness Algorithm (CFA$\theta$) which enables a continuous interpolation between different fairness definitions. More specifically, we make three main contributions to the existing literature. First, our approach allows the decision maker to continuously vary between specific concepts of individual and group fairness. As a consequence, the algorithm enables the decision maker to adopt intermediate ``worldviews'' on the degree of discrimination encoded in algorithmic processes, adding nuance to the extreme cases of ``we're all equal'' (WAE) and ``what you see is what you get'' (WYSIWYG) proposed so far in the literature. Second, we use optimal transport theory, and specifically the concept of the barycenter, to maximize decision maker utility under the chosen fairness constraints. Third, the algorithm is able to handle cases of intersectionality, i.e., of multi-dimensional discrimination of certain groups on grounds of several criteria. We discuss three main examples (credit applications; college admissions; insurance contracts) and map out the legal and policy implications of our approach. The explicit formalization of the trade-off between individual and group fairness allows this post-processing approach to be tailored to different situational contexts in which one or the other fairness criterion may take precedence. Finally, we evaluate our model experimentally.Comment: Vastly extended new version, now including computational experiment

A review of the effectiveness of lower limb orthoses used in cerebral palsy

To produce this review, a systematic literature search was conducted for relevant articles published in the period between the date of the previous ISPO consensus conference report on cerebral palsy (1994) and April 2008. The search terms were 'cerebral and pals* (palsy, palsies), 'hemiplegia', 'diplegia', 'orthos*' (orthoses, orthosis) orthot* (orthotic, orthotics), brace or AFO