Congestion management in traffic-light intersections via Infinitesimal Perturbation Analysis

We present a flow-control technique in traffic-light intersections, aiming at regulating queue lengths to given reference setpoints. The technique is based on multivariable integrators with adaptive gains, computed at each control cycle by assessing the IPA gradients of the plant functions. Moreover, the IPA gradients are computable on-line despite the absence of detailed models of the traffic flows. The technique is applied to a two-intersection system where it exhibits robustness with respect to modeling uncertainties and computing errors, thereby permitting us to simplify the on-line computations perhaps at the expense of accuracy while achieving the desired tracking. We compare, by simulation, the performance of a centralized, joint two-intersection control with distributed control of each intersection separately, and show similar performance of the two control schemes for a range of parameters

Si desea que la guerra termine, hay que decirlo en voz alta: un estudio del acuerdo provisional entre las FARC y Colombia sobre drogas ilícitas

Although still neglected in legal writings, the 2014 agreement on illicit drugs between the FARC and the Colombian Government deserves attention for a number of reasons, including that it was conceived as an essential part of the broader strategy for peace in Colombia, as well as because of its aim of eradicating illicit crops. Starting with some remarks on the Colombian ‘drug war’ and the policy and legal arguments for classifying the Colombian armed conflict as a non-international armed conflict (NIAC), the paper will then proceed with an analysis of the main reasons behind the drafting of a partial agreement on illicit drugs between the FARC and Colombia in 2014. Next, the paper will address the relevant sections and enforcement mechanisms for putting the provisions of the agreement into effect. An assessment of how the 2014 agreement has addressed the issue of drug trafficking and the issues concerning drug related crimes will also be considered. The paper will conclude with the lessons to be drawn from the new Agreement on illicit drugs.Aunque todavía es un tema descuidado por la doctrina, el Acuerdo de 2014 sobre las drogas ilícitas entre el Gobierno de Colombia y las FARC, merece atención por muchas razones, incluyendo el que fue concebido como una parte esencial de una estrategia más amplia para la paz en Colombia, así como por su objetivo de erradicar los cultivos ilícitos. Se parte de algunas observaciones sobre la “guerra contra las drogas ‘de Colombia y la política y los argumentos jurídicos para clasificar el conflicto armado en Colombia como un conflicto armado no internacional. Seguidamente se hace un análisis de las principales razones que hay detrás de la elaboración de un acuerdo parcial sobre las drogas ilícitas entre las FARC y Colombia en 2014. A continuación, este trabajo se dirige a los mecanismos de aplicación para poner que sus disposiciones entren en vigor. Se hace, igualmente, una evaluación de la forma en que el Acuerdo de 2014 ha abordado la cuestión del tráfico de drogas y también se examinan las cuestiones relativas a los delitos relacionados con las drogas. El trabajo concluye con las lecciones que caben extraer del nuevo Acuerdo sobre las drogas ilícitas

Fast Discrete Consensus Based on Gossip for Makespan Minimization in Networked Systems

In this paper we propose a novel algorithm to solve the discrete consensus problem, i.e., the problem of distributing evenly a set of tokens of arbitrary weight among the nodes of a networked system. Tokens are tasks to be executed by the nodes and the proposed distributed algorithm minimizes monotonically the makespan of the assigned tasks. The algorithm is based on gossip-like asynchronous local interactions between the nodes. The convergence time of the proposed algorithm is superior with respect to the state of the art of discrete and quantized consensus by at least a factor O(n) in both theoretical and empirical comparisons

A new approach for diagnosability analysis of Petri nets using Verifier Nets

In this paper, we analyze the diagnosability properties of labeled Petri nets. We consider the standard notion of diagnosability of languages, requiring that every occurrence of an unobservable fault event be eventually detected, as well as the stronger notion of diagnosability in K steps, where the detection must occur within a fixed bound of K event occurrences after the fault. We give necessary and sufficient conditions for these two notions of diagnosability for both bounded and unbounded Petri nets and then present an algorithmic technique for testing the conditions based on linear programming. Our approach is novel and based on the analysis of the reachability/coverability graph of a special Petri net, called Verifier Net, that is built from the Petri net model of the given system. In the case of systems that are diagnosable in K steps, we give a procedure to compute the bound K. To the best of our knowledge, this is the first time that necessary and sufficient conditions for diagnosability and diagnosability in K steps of labeled unbounded Petri nets are presented

Performance Regulation and Tracking via Lookahead Simulation: Preliminary Results and Validation

This paper presents an approach to target tracking that is based on a variable-gain integrator and the Newton-Raphson method for finding zeros of a function. Its underscoring idea is the determination of the feedback law by measurements of the system's output and estimation of its future state via lookahead simulation. The resulting feedback law is generally nonlinear. We first apply the proposed approach to tracking a constant reference by the output of nonlinear memoryless plants. Then we extend it in a number of directions, including the tracking of time-varying reference signals by dynamic, possibly unstable systems. The approach is new hence its analysis is preliminary, and theoretical results are derived for nonlinear memoryless plants and linear dynamic plants. However, the setting for the controller does not require the plant-system to be either linear or stable, and this is verified by simulation of an inverted pendulum tracking a time-varying signal. We also demonstrate results of laboratory experiments of controlling a platoon of mobile robots.Comment: A modified version will appear in Proc. 56th IEEE Conf. on Decision and Control, 201