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In this note, we want to provide a comparison among the efficiency of different approaches for the verification of K-step and infinite-step opacity based on three different graphs: the Extended Basis Reachability Graph (EBRG), the Basis Reachability Graph (BRG) when applicable, and the Reachability Graph (RG)., Comment: 8 pages

For high-density metro traffic, nowadays the time-variant passenger flow is the main cause of train delays and stranded passengers. Typically, the main objective of automatic metro traffic regulation methods is to minimize the delay time of trains while passengers' satisfaction is not considered. Instead, in this work, a novel framework that integrates a passenger flow module (PFM) and a train operation module (TOM) is proposed with the aim of simultaneously minimizing traffic delays and passengers' discomfort. In particular, the PFM is devoted to the optimization of the headway time in case of platform overcrowding, so as to reduce the passengers waiting time at platforms and increase the load rate of trains; while the TOM is devoted to the minimization of trains' delays. The two modules interact with each other so that the headway time is automatically adjusted when a platform is overcrowded, and the train traffic is immediately regulated according to the new headway time. As a result, the number of passengers on the platform and their total waiting time can be significantly reduced. Numerical results are provided to show the effectiveness of the proposed method in improving the operation performance while minimizing the passengers' discomfort., Comment: This work has been submitted to the 2021 IEEE International Intelligent Transportation Systems Conference (ITSC)

This paper addresses the problem of infinite-step opacity and K-step opacity of discrete event systems modeled with Petri nets. A Petri net system is said to be infinite-step/K-step opaque if all its secret states remains opaque to an intruder for any instant within infinite/K steps. In other words, the intruder is never able to ascertain that the system used to be in a secrete state within infinite/K steps based on its observation of the systems evolution. Based on the notion of basis reachability and the twoway observer, an efficient approach to verify infinite-step opacity and K-step opacity is proposed., Comment: 8 pages, 5 figures. arXiv admin note: text overlap with arXiv:1908.09604, arXiv:1903.07827, arXiv:1903.09298

Detectability describes the property of a system to uniquely determine, after a finite number of observations, the current and subsequent states. In this paper, to reduce the complexity of checking the detectability properties in the framework of bounded labeled Petri nets, we use a new tool, which is called detector, to verifying the strong detectability and periodically strong detectability. First, an approach, which is based on the reachable graph and its detector, is proposed. Then, we develop a novel approach which is based on the analysis of the detector of the basis reachability graph. Without computing the whole reachability space, and without building the observer, the proposed approaches are more efficient., Comment: 8 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1903.09298, arXiv:1903.07827

Detectability describes the property of a system whose current and the subsequent states can be uniquely determined after a finite number of observations. In this paper, we developed a novel approach to verifying strong detectability and periodically strong detectability of bounded labeled Petri nets. Our approach is based on the analysis of the basis reachability graph of a special Petri net, called Verifier Net, that is built from the Petri net model of the given system. Without computing the whole reachability space and without enumerating all the markings, the proposed approaches are more efficient., Comment: arXiv admin note: text overlap with arXiv:1903.07827

Detectability describes the property of an system whose current and the subsequent states can be uniquely determined after a finite number of observations. In this paper, we relax detectability to C-detectability that only requires a given set of crucial states can be distinguished from other states. Four types of C-detectability: strong C-detectability, weak C-detectability, periodically strong C-detectability, and periodically weak C-detectability are defined in the framework of labeled Petri nets, which have larger modeling power than finite automata. Moreover, based on the notion of basis markings, the approaches are developed to verify the four C-detectability of a bounded labeled Petri net system. Without computing the whole reachability space and without enumerating all the markings consistent with an observation, the proposed approaches are more efficient., Comment: Information Sciences (2020)

One less addressed issue of deep reinforcement learning is the lack of generalization capability based on new state and new target, for complex tasks, it is necessary to give the correct strategy and evaluate all possible actions for current state. Fortunately, deep reinforcement learning has enabled enormous progress in both subproblems: giving the correct strategy and evaluating all actions based on the state. In this paper we present an approach called orthogonal policy gradient descent(OPGD) that can make agent learn the policy gradient based on the current state and the actions set, by which the agent can learn a policy network with generalization capability. we evaluate the proposed method on the 3D autonomous driving enviroment TORCS compared with the baseline model, detailed analyses of experimental results and proofs are also given., Comment: accepted as conference paper of IEEE/ICSESS2018

In March and early April 2013, a new avian-origin influenza A (H7N9) virus (A-OIV) emerged in the eastern China. During the first week of April, the 18 infection cases have been confirmed and 6 people have died since March. This virus has caused global concern as a potential pandemic threat. Here we use evolutionary analysis to reconstruct the origins and early development of the A-OIV viruses. We found that A-OIV was derived from a reassortment of three avian flu virus strains, and substantial mutations have been detected. Our results highlight the need for systematic surveillance of influenza in birds, and provide evidence that the mixing of new genetic elements in avian can result in the emergence of viruses with pandemic potential in humans., Comment: 8 pages, 5 figures, 2 table