Design and analysis of multi-hospital kidney exchange mechanisms using random graphs

Kidney exchanges enable transplants when a pair of a patient and an incompatible donor is matched with other similar pairs. In multi-hospital kidney exchanges pairs are pooled from multiple hospitals, and each hospital is able to decide which pairs to report and which to hide and match locally. Modeling the problem as a maximum matching on a random graph, we first establish that the expected benefit from pooling scales as the square-root of the number of pairs in each hospital. We design the xCM mechanism, which achieves efficiency and incentivizes hospitals of moderate-to-large size to fully report their pairs. Reciprocal pairs are crucial in the design, with the probabilistic uniform rule used to ensure incentive alignment. By grouping certain pair types into so-called virtual-reciprocal pairs, xCM extends to handle 3-cycles. We validate the performance of xCM in simulation, demonstrating its efficiency and incentive advantages over the Bonus mechanism (Ashlagi and Roth, 2014).Engineering and Applied Science

Algoritmo de metodología para desarrollar dispositivos mecatrónicos como ayuda a personas con distrofia muscular

El avance tecnológico permite desarrollar equipos tecnológicos y ayudas técnicas que apoyen el tratamiento dirigido a un paciente.Objetivo: Generar un algoritmo para desarrollar dispositivos mecatrónicos como ayudas técnicas para personas con discapacidad física.                                                                                                        Métodos: Se tomó como base una clasificación del diseño de estudio de tipo descriptivo, para la propuesta de una metodología de diseño e implementación de dispositivos de ayuda técnica en personas con distrofia muscular.  La propuesta hace referencia al conjunto de técnicas, procedimientos y soportes documentales empleados en el diseño de sistemas de ayuda técnica, donde se integran aspectos diversos de tal forma que el proceso global sea lógico y comprensible.Resultados: El diseño obtenido comprende el desarrollo de cuatro metodologías, que inician con el proceso investigativo, luego el dispositivo mecánico, después el sistema electrónico y finaliza con el sistema de comunicación. Se dan pautas para generar cada uno de los componentes del sistema y lograr obtener un dispositivo funcional. El diseño fue probado con resultados favorables.Conclusiones: En el área de rehabilitación física, se combinan los conocimientos médicos con los ingenieriles para obtener soluciones tecnológicas que facilitan las labores a personas con discapacidad física. El diseño desarrollado, al contar con un conjunto ordenado de operaciones sistemáticas y una serie de pautas específicas para la ejecución de actividades, donde se cursan una serie de etapas, permite solucionar el tipo de problemas de referencia.Palabras clave: Ayudas técnicas; Rehabilitación médica; Exoesqueleto</p

Adapting a Kidney Exchange Algorithm to Align with Human Values

The efficient and fair allocation of limited resources is a classical problem in economics and computer science. In kidney exchanges, a central market maker allocates living kidney donors to patients in need of an organ. Patients and donors in kidney exchanges are prioritized using ad-hoc weights decided on by committee and then fed into an allocation algorithm that determines who gets what--and who does not. In this paper, we provide an end-to-end methodology for estimating weights of individual participant profiles in a kidney exchange. We first elicit from human subjects a list of patient attributes they consider acceptable for the purpose of prioritizing patients (e.g., medical characteristics, lifestyle choices, and so on). Then, we ask subjects comparison queries between patient profiles and estimate weights in a principled way from their responses. We show how to use these weights in kidney exchange market clearing algorithms. We then evaluate the impact of the weights in simulations and find that the precise numerical values of the weights we computed matter little, other than the ordering of profiles that they imply. However, compared to not prioritizing patients at all, there is a significant effect, with certain classes of patients being (de)prioritized based on the human-elicited value judgments

Game theoretical analysis of Kidney Exchange Programs

The goal of a kidney exchange program (KEP) is to maximize number of transplants within a pool of incompatible patient-donor pairs by exchanging donors. A KEP can be modelled as a maximum matching problem in a graph. A KEP between incompatible patient-donor from pools of several hospitals, regions or countries has the potential to increase the number of transplants. These entities aim is to maximize the transplant benefit for their patients, which can lead to strategic behaviours. Recently, this was formulated as a non-cooperative two-player game and the game solutions (equilibria) were characterized when the entities objective function is the number of their patients receiving a kidney. In this paper, we generalize these results for $N$-players and discuss the impact in the game solutions when transplant information quality is introduced. Furthermore, the game theory model is analyzed through computational experiments on instances generated through the Canada Kidney Paired Donation Program. These experiments highlighting the importance of using the concept of Nash equilibrium, as well as, the anticipation of the necessity to further research for supporting police makers once measures on transplant quality are available