Probably Approximately Correct Nash Equilibrium Learning

We consider a multi-agent noncooperative game with agents' objective functions being affected by uncertainty. Following a data driven paradigm, we represent uncertainty by means of scenarios and seek a robust Nash equilibrium solution. We treat the Nash equilibrium computation problem within the realm of probably approximately correct (PAC) learning. Building upon recent developments in scenario-based optimization, we accompany the computed Nash equilibrium with a priori and a posteriori probabilistic robustness certificates, providing confidence that the computed equilibrium remains unaffected (in probabilistic terms) when a new uncertainty realization is encountered. For a wide class of games, we also show that the computation of the so called compression set - a key concept in scenario-based optimization - can be directly obtained as a byproduct of the proposed solution methodology. Finally, we illustrate how to overcome differentiability issues, arising due to the introduction of scenarios, and compute a Nash equilibrium solution in a decentralized manner. We demonstrate the efficacy of the proposed approach on an electric vehicle charging control problem.Comment: Preprint submitted to IEEE Transactions on Automatic Contro

The Collaborative Production of Responses and Dispatching on the Radio: Video Analysis in a Medical Emergency Call Center

¿Qué ocurre cuando alguien llama a un teléfono de emergencia? ¿Cómo se gestiona la emergencia? ¿Cómo se pone en funcionamiento el servicio de emergencia? Una intervención rápida y competente, así como la valoración de la dificultad de la situación en pocos y decisivos segundos son los estándares de calidad que regulan la organización de las centrales de emergencia. Desde hace algunos años diferentes grupos de investigación en ciencias sociales desarrollan un sistemático programa de investigación sobre actividades de trabajo empleando métodos etnográficos naturalistas. Este interés no es nuevo en las ciencias sociales, especialmente en la sociología. La novedad reside en la específica perspectiva analítica empleada en estas investigaciones. Este programa renuncia a la teorización a gran escala y se concentra en el estudio empírico de actividades y prácticas, alcanzando un nivel de detalle y finura analítica sin precedentes. De hecho, sólo procediendo en este nivel de detalle, posible gracias al registro en video, podemos documentar la extraordinaria y sutil producción del trabajo en colaboración en un grado que está más allá de aquello que puede ser percibido por las personas en su rutina cotidiana. Este aspecto concierne en particular a la última generación de estudios sobre el trabajo, que documenta los procedimientos tácitos y las formas del razonamiento del sentido común comprendidas en el desarrollo de actividades en determinados ámbitos. Este artículo se centra en las formas en las que se desarrollan las tareas en los centros médicos de emergencia. Aunque conocemos mucho, gracias a investigaciones previas, sobre la interacción que se produce entre quien realiza la llamada y quien la recibe, sabemos poco sobre la organización social que hace posible las órdenes y tareas en el centro. Los datos analizados en este artículo provienen de un proyecto de investigación en el que he participado durante algunos años en los call-centers del número de emergencia telefónico 118. La comparación de los datos obtenidos del registro de audio con aquellos del registro de video permite ilustrar cómo una orden no consiste únicamente en una transferencia de información, sino que es el resultado de un intenso trabajo de coordinación entre los diferentes actores, tanto cara a cara, como a través de la mediación de aparatos técnicos. URN: urn:nbn:de:0114-fqs0803408Was geschieht, wenn jemand bei einer Notfallnummer um Hilfe anruft? Wie wird mit dem Notfall umgegangen? Wie wird der Notfalldienst in Gang gesetzt? Eine unverzügliche und kompetente Intervention sowie die Einschätzung der Schwere der Situation innerhalb weniger entscheidender Sekunden markieren die Qualitätsstandards, welche die Organisation von Notfallzentralen regulieren. Seit einigen Jahren führen verschiedene sozialwissenschaftliche Forschungsgruppen ein Programm der systematischen Untersuchung von Arbeitstätigkeiten durch, bei dem ethnografische und naturalistische Methoden eingesetzt werden. Das Interesse an Arbeitstätigkeiten ist zweifellos in den Sozialwissenschaften und besonders in der Soziologie keineswegs neu. Neu ist allerdings die spezifische analytische Perspektive, unter der diese Forschungen durchgeführt werden: Dieses Programm verzichtet auf "großartiges Theoretisieren" und konzentriert sich stattdessen auf die empirische Untersuchung von Aktivitäten und Praktiken. Dabei wird eine beispiellose Detailgenauigkeit und analytische Feinheit erreicht. In der Tat hat erst dieses Vorgehen auf der Ebene feinster Details, die durch den Einsatz von Videoaufzeichnungen zugänglich werden, ermöglicht, die außerordentliche und subtile kollaborative "Herstellung von Arbeit" zu dokumentieren, und zwar auf eine Ebene ausgedehnt, die sich jenseits dessen erstreckt, was Menschen in ihren Alltagsroutinen bewusst wahrzunehmen vermögen. Dieser Aspekt betrifft insbesondere die Befähigung der jüngsten "Studies of Work", jene stillschweigenden Prozeduren und Formen des Common-Sense-Denkens zu dokumentieren, die in die Ausführung von Tätigkeiten in bestimmten Arbeitsfeldern involviert sind. Dieser Aufsatz fokussiert darauf, wie die Auftragsabwicklung in medizinischen Notfallzentralen erfolgt. Obwohl aus vorangegangenen Untersuchungen über die Interaktion zwischen Anrufenden und Angerufenen bekannt ist, wissen wir über die soziale Organisation, die die Auftragsabwicklung ermöglicht, sehr viel weniger. Die Daten, über die hier berichtet wird, stammen aus einem Forschungsprojekt über Einsatzzentralen der 118-Notfallrufnummmer in Italien, an dem ich seit einigen Jahren beteiligt bin. Durch den Kontrast von Audio- und Videoaufzeichnungen werde ich zeigen, dass die Auftragsabwicklung nicht aus reinem Informationstransfer besteht, sondern dass Ergebnisse aus einer intensiven Koordinationsarbeit zwischen den beteiligten Handelnden resultieren, die sowohl Face-to-Face also auch medial vermittels technischer Apparate erfolgt. URN: urn:nbn:de:0114-fqs0803408What happens when someone rings an emergency hotline for help? How is the emergency handled? How does the emergency service swing into action? Prompt and competent intervention and assessment of the gravity of the situation in a few crucial seconds: these are the quality standards that regulate the organization of emergency operations centers. For a number of years various groups of social science researchers have carried forward a program for the systematic study of work using ethnographic and naturalistic methods of analysis. An interest in work is certainly nothing new in the social sciences, and in sociology in particular. What is new, though, is the particular analytical viewpoint from which such research is now conducted. This program has dispensed with large-scale theorization and has concentrated on the empirical study of activities and practices, achieving an unprecedented level of detail and analytical fineness. Indeed, only by proceeding at this fine level of detail—made possible by the use of videorecordings—has it been possible to document the extraordinary and subtle collaborative production of work, and to do so at a level which extends well beyond the conscious awareness of people in their everyday routine. This aspect concerns in particular the capacity of the latest generation of studies of work to document the tacit procedures and forms of common-sense reasoning involved in the performance of tasks in concrete work settings. This paper focuses on the ways in which the dispatch is done in a medical emergency operation center. Although we know a great deal about the interaction between caller and call-taker from previous research, we know much less about the social organization that makes the dispatch possible. The data analyzed in this paper derive from a research project in which I have been engaged for a number of years on operation centers for the 118 emergency telephone number in Italy. Contrasting the data obtained from audiorecording with the data obtained from videorecording, I will show that a dispatch does not consist purely in information transfer, but is the outcome of intense coordination work among the actors involved face to face and through the mediation of technological apparatus. URN: urn:nbn:de:0114-fqs080340

NYC Administration for Children\u27s Services Child Abuse and Neglect Prevention Polices, Program and Laws

Despite efforts and financial resources invested in the prevention of child abuse and neglect in New York City (NYC), many children are still in danger of being victimized by their parents or caregivers. The general public\u27s assumption is that the NYC Administration for Children\u27s Services (ACS) either does not have efficient policies, programs, or laws to protect at-risk children, or these are not being properly implemented. The purpose of this qualitative study was to provide a thorough analysis of ACS policies, programs, and laws based on information gained from interviews with child welfare experts. Newberger and Newberger\u27s social support theory provided the theoretical framework for the study. The methodology was a holistic case study design in which data were analyzed and collected through semi structured face-to-face interviews with 12 child welfare experts, archival records, and publicly available documents from ACS, the New York State Office of Children and Family Services, and NYC family court websites. Five themes emerged after the data were inductively coded and subjected to a content analytical procedure: implementation of programs, policies, and laws; areas of policies and programs that need improvement; reasons for failure of child abuse prevention; communication problems; and risk factors for child abuse and neglect. The key finding of this study was that child abuse and neglect prevention policies, programs, and laws were not adequately implemented. The study concludes with recommendations to retrain workers and to conduct a reexamination of existing child abuse prevention policies, programs, and laws to meet the needs of NYC at-risk children

From Software Specifics to Software-Specific Vagueness

The paper identifies some recurrent forms of ‘software-specific’ vagueness in the context of software engineering work practices as a set of conditions for establishing shared understanding between engineers and users on the features and possible uses of the system. Relying in particular on about 20 hours of audio-video recording of meetings between the software engineers and users at three different sites, the paper identifies three recurrent patterns of ‘software-specific’ vagueness: (i) “openness versus completenessâ€, that is, the extent to which the software-based modeling tool requirement of internal completeness hampers the flexibility crucial to its function; (ii) “representation versus coordinationâ€, that is, the degree of recognizability of system features as management support functions of control with respect to line work management functions and (iii) “object orientation versus procedural orientationâ€, that is, the order that the model imposes on interaction and the representations of interaction located within the object instead of on a procedural level as in e.g. issue lists. Contrary to expectations concerning software engineering when it is viewed as a matter of logic, the establishment of a common ground of reference between engineers and users does not rely on making instructions about the software more accurate, more detailed or more specific. Rather, the paper argues that the vagueness of many expressions, specifically with regard to openness, coordination functions and procedural-orientation of the software, helps build a shared understanding

A posteriori probabilistic feasibility guarantees for Nash equilibria in uncertain multi-agent games

In this paper a distribution-free methodology is presented for providing robustness guarantees for Nash equilibria (NE) of multi-agent games. Leveraging recent a posteriori developments of the so called scenario approach (Campi et al., 2018), we provide probabilistic guarantees for feasibility problems with polytopic constraints. This result is then used in the context of multi-agent games, allowing to provide robustness certificates for constraint violation of any NE of a given game. Our guarantees can be used alongside any NE seeking algorithm that returns some equilibrium solution. Finally, by exploiting the structure of our problem, we circumvent the need of employing computationally prohibitive algorithms to find an irreducible support subsample, a concept at the core of the scenario approach. Our theoretical results are accompanied by simulation studies that investigate the robustness of the solutions of two different problems, namely, a 2-dimensional feasibility problem and an electric vehicle (EV) charging control problem

A priori data-driven robustness guarantees on strategic deviations from generalised Nash equilibria

In this paper we focus on noncooperative games with uncertain constraints coupling the agents' decisions. We consider a setting where bounded deviations of agents' decisions from the equilibrium are possible, and uncertain constraints are inferred from data. Building upon recent advances in the so called scenario approach, we propose a randomised algorithm that returns a nominal equilibrium such that a pre-specified bound on the probability of violation for yet unseen constraints is satisfied for an entire region of admissible deviations surrounding it, thus supporting neighbourhoods of equilibria with probabilistic feasibility certificates. For the case in which the game admits a potential function, whose minimum coincides with the social welfare optimum of the population, the proposed algorithmic scheme opens the road to achieve a trade-off between the guaranteed feasibility levels of the region surrounding the nominal equilibrium, and its system-level efficiency. Detailed numerical simulations corroborate our theoretical results

On the probabilistic feasibility of solutions in multi-agent optimization problems under uncertainty

We investigate the probabilistic feasibility of randomized solutions to two distinct classes of uncertain multi-agent optimization programs. We first assume that only the constraints of the program are affected by uncertainty, while the cost function is arbitrary. Leveraging recent a posteriori developments of the scenario approach, we provide probabilistic guarantees for all feasible solutions of the program under study. This result is particularly useful in cases where numerical difficulties related to the convergence of the solution-seeking algorithm hinder the exact quantification of the optimal solution. Furthermore, it can be applied to cases where the agents' incentives lead to a suboptimal solution, e.g., under a non-cooperative setting. We then focus on optimization programs where the cost function admits an aggregate representation and depends on uncertainty while constraints are deterministic. By exploiting the structure of the program under study and leveraging the so called support rank notion, we provide agent-independent robustness certificates for the optimal solution, i.e., the constructed bound on the probability of constraint violation does not depend on the number of agents, but only on the dimension of the agents' decision. This substantially reduces the number of samples required to achieve a certain level of probabilistic robustness as the number of agents increases. All robustness certificates provided in this paper are distribution-free and can be used alongside any optimization algorithm. Our theoretical results are accompanied by a numerical case study involving a charging control problem of a fleet of electric vehicles

Coalitional model predictive control for systems of systems

An aspect so far rarely contemplated in distributed control problems is the explicit consideration of individual (local) interests of the components of a complex system. Indeed, the focus of the majority of the literature about distributed control has been the overall system performance. While on one hand this permitted to address fundamental properties of centralized control, such as system-wide optimality and stability, one the other hand it implied assuming unrestricted cooperation across local controllers. However, when dealing with multi-agent systems with a strong heterogeneous character, cooperation between the agents cannot be taken for granted (due to, for example, logistics, market competition), and selfish interests may not be neglected. Another critical point that must be kept into consideration is the diversity characterizing systems of systems (SoS), yielding very complex interactions between the agents involved (one example of such system is the smart grid). In order to tackle such inherent aspects of SoS, the research presented in this thesis has been concerned with the development of a novel framework, the coalitional control, that extends the scope of advanced control methods (in particular MPC) by drawing concepts from cooperative game theory that are suited for the inherent heterogeneity of SoS, providing as well an economical interpretation useful to explicitly take into account local selfish interests. Thus, coalitional control aims at governing the association/dissociation dynamics of the agents controlling the system, according to the expected benefits of their possible cooperation. From a control theoretical perspective, this framework is founded on the theory of switched systems and variable structure/topology networked systems, topics that are recently experiencing a renewed interest within the community. The main concepts and challenges in coalitional control, and the links with cooperative network game theory are presented in this document, tracing a path from model partitioning to the control schemes whose principles delineate the idea of coalitional control. This thesis focuses on two basic architectures: (i) a hierarchically supervised evolution of the coalitional structure, and (ii) a protocol for autonomous negotiation between the agents, with specific mechanisms for benefit redistribution, leading to the emergence of cooperating clusters.Premio Extraordinario de Doctorado U

Impact of spatiotemporal heterogeneity in heat pump loads on generation and storage requirements

This paper investigates how spatiotemporal heterogeneity in inflexible residential heat pump loads affects the need for storage and generation in the electricity system under business-as-usual and low-carbon emissions budgets. Homogeneous and heterogeneous heat pump loads are generated using population-weighted average and local temperature, respectively, assuming complete residential heat pump penetration. The results of a storage and generation optimal expansion model with network effects for spatiotemporally homogeneous and heterogeneous load profiles are compared. A case study is performed using a 3-bus network of London, Manchester, and Glasgow in Britain for load and weather data for representative weeks. Using heterogeneous heating demand data changes storage sizing: under a business-as-usual budget, 26% more total storage is built on an energy and power basis, and this storage is distributed among all of the buses in the heterogeneous case. Under a low-carbon budget, total energy storage at all buses increases 2 times on an energy basis and 40% on a power basis. The energy to power ratio of storage at each bus also increases when accounting for heterogeneity; this change suggests that storage will be needed to provide energy support in addition to power support for electric heating in high-renewable power systems. Accounting for heterogeneity also increases modeled systems costs, particularly capital costs, because of the need for higher generation capacity in the largest load center and coincidence of local peak demand at different buses. These results show the importance of accounting for heat pump load heterogeneity in power system planning.Comment: 6 pages, 4 figures, to be published in the proceedings of the IEEE Power and Energy Society General Meeting 202