Zhiwu Li

Zhiwu Li
Xidian University · School of Mechano-Electronic Engineering

PhD
I am giving an in-person class of discrete-event systems.

About

707
Publications
121,248
Reads
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14,627
Citations
Introduction
I am a Professor in Automation with major interests in supervisory control of discrete event systems, Granular computing, and secuity of networked systems.
Additional affiliations
January 2010 - present
Martin-Luther-Universität Halle-Wittenberg
January 2010 - present
New Jersey Institute of Technology
January 2008 - present

Publications

Publications (707)
Article
Predicting energy demands based on the past energy consumption can allow a reasonable allocation of energy resource to avoid waste and improve utilization. To this end, linear or nonlinear forecasting models are applied. Some researchers use support vector regression models to deal with the energy consumption prediction problem as they can handle w...
Article
With the rapid development of electric vehicles, the disposal of retired lithium batteries is a grand challenge for the waste management based on reliability, efficiency and sustainability criteria. Majority of studies in the literature review, have focused on the minimization of environmental pollution while maximizing economic profits. However, t...
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Nuclear power equipment is a national name card which plays an important role in the nuclear power supply of the new generation of onshore nuclear power plants, submarine aircar carriers, marine development, deep space exploration and other major national projects. From the designation to decommissioning of nuclear power equipment, lifecycle digita...
Article
Owing to the continuous increase in the proportion of solar generation accounting for the total global generation, real-time management of solar power has become indispensable. Moreover, accurate prediction of photovoltaic power is emerging as an important link to support grid operations and reflect real-life scenarios. Various studies have led to...
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We investigate modular supervisory control of discrete-event systems composed of several groups of components, where each group consists of similar modules. Because of the similar structures of the modules, such systems can be represented as a set of (group) templates. Supervisory control can then be performed on these templates, resulting in a set...
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The recent advances in the intelligent transportation systems (ITS) are reviewed in this Special Issue in which many techniques in mathematics, artificial intelligence, machine learning, automatic control, and optimization theory were considered to address the ITS based on recent technologies, methods and symmetries [...]
Article
It is a trend for a production system to produce multiple product types with small batches. Thus, there are frequent switches between batches. Due to the different product types in different batches, setups may be necessary for a batch changeover. Based on practical applications, we investigate the problem of scheduling a class of two-stage hybrid...
Article
In the discrete event systems literature, the studies addressing opacity usually assume a passive intruder, who has full knowledge of the structure of a system but with only a partial observation ability. This work touches upon the opacity problem in discrete event systems modeled with labeled Petri nets , by assuming the existence of an active int...
Article
This work proposes a novel architecture of a human-cyber-physical system (HCPS) to operate nuclear reactors in the context of next-generation artificial intelligence (NGAI) technologies. Developing the generation IV nuclear power plant requires NGAI to fulfill intelligent operation and thereby enhance reliability and safety. Nevertheless, the NGAI...
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Petri nets are used to design deadlock control strategies for flexible manufacturing systems (FMSs), which typically involve the addition of monitors and the associated arcs to the FMS. The addition of several monitors and associated arcs to the first constructed Petri net model significantly complicates the Petri net controller. This paper develop...
Article
In this study, we establish a new design methodology of granular models realized by augmenting the existing numeric models through analyzing and modeling their associated prediction error. Several novel approaches to the construction of granular architectures through augmenting existing numeric models by incorporating modeling errors are proposed i...
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In this paper, an asymmetrical congestion game is used to build a fairness concern‐based coordinated route guidance model for alleviating traffic congestion. Coordinated vehicle route guidance is commonly recognized as an effective way to alleviate the “route flapping” phenomenon, where a new congestion appears since numerous vehicles obey the same...
Article
This study opens an original avenue of designing interpretable fuzzy rule-based models realized in the presence of data characterized by a large number of attributes (input variables). In the presence of such high-dimensional data, the development of rule-based models faces serious challenges both at the design and interpretability level. To addres...
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Emergencies, such as pandemics (e.g., COVID-19), warrant urgent production and distribution of goods under disrupted supply chain conditions. An innovative logistics solution to meet the urgent demand during emergencies could be the factory-in-a-box manufacturing concept. The factory-in-a-box manufacturing concept deploys vehicles to transport cont...
Preprint
Inspired by privacy problems where the behavior of a system should not be revealed to an external curious observer, we investigate event concealment and concealability enforcement in discrete event systems modeled as non-deterministic finite automata under partial observation. Given a subset of secret events in a given system, concealability holds...
Article
This research presents a hybrid model for multi‐step, interval forecasting of air quality indices. An efficient preprocessing module is applied to split the raw data into various sub‐series and the optimal mode of data input is determined through feature selection. A multi‐objective optimization algorithm is proposed to tune the parameters of kerne...
Article
A distributed flow-shop scheduling problem with lot-streaming that considers completion time and total energy consumption is addressed. It requires to optimally assign jobs to multiple distributed factories and, at the same time, sequence them. A biobjective mathematic model is first developed to describe the considered problem. Then, an improved J...
Preprint
In this paper, we revisit the verification of strong K-step opacity (K-SSO) for partially-observed discrete-event systems modeled as nondeterministic finite-state automata. As a stronger version of the standard K-step opacity, K-SSO requires that an intruder cannot make sure whether or not a secret state has been visited within the last K observabl...
Article
As the penetration rate of solar energy in the grid continues to enhance, solar power photovoltaic generation forecasts have become an indispensable aspect of mechanism mobilization and maintenance of the stability of the power system. In this regard, many researchers have done a lot of study, and put forward some predictive models. However, many i...
Article
Accurate wind speed prediction has become increasingly important in wind power generation. However, the lack of efficient data preprocessing techniques and integration strategies has been a big obstacle to the development of wind power forecasting system. Therefore, a novel and advanced combined forecasting system comprising a data preprocessing, a...
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With the rapid development of global industrialization and urbanization, as well as the continuous expansion of the population, large amounts of industrial exhaust gases and automobile exhaust are released. To better sound an early warning of air pollution, researchers have proposed many pollution prediction methods. However, the traditional point...
Article
This paper deals with the fault diagnosis problem of discrete event systems modeled with labeled Petri nets. Its main contributions are threefold. First, depending on whether a diagnosis function examines the fault transitions that possibly occur after the last observed event, we formally divide the diagnosis functions into two types: optimistic an...
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In recent years, the XACML (eXtensible Access Control Markup Language) is widely used in a variety of research fields, especially in access control. However, when policy sets defined by the XACML become large and complex, the policy evaluation time increases significantly. In order to improve policy evaluation performance, we propose an optimizatio...
Article
Short-term scheduling of oil refinery operations is a complicated optimization problem that requires a high level of detail and needs efficient approaches and software tools. Oil refineries are naturally categorized as continuous process industries due to their production processes, which have essentially different characteristics and constraints f...
Article
This paper investigates the deadlock prevention problem for Petri nets (PN), in which the control is performed by appropriately setting time constraints on transitions, in terms of firing intervals. We show that this time based deadlock prevention (TBDP) problem is decidable for bounded PN and can be formalised as a parametric model checking proble...
Article
Optimization design of product structures is a critical point of intelligent manufacturing that is often overlooked, particularly their performance balance involving different uncertainties. It is urgent to connect product consumers, design experts, and manufacturing plants to balance the optimization of product structures. As an input of intellige...
Article
In this paper we study the problem of enforcing a generalized mutual exclusion constraint (GMEC) in a labeled Petri net that contains indistinguishable transitions by a monitor-based supervisor. We show that a monitor-based supervisor can be designed based on the influence of events if the GMEC is deterministic. On the other hand, for a nondetermin...
Article
This article proposes a semi-structural approach to verify the nonblockingness of a Petri net. We construct a structure, called minimal-maximal basis reachability graph (min-max-BRG): it provides an abstract description of the reachability set of a net while preserving all information needed to test if the net is blocking. We prove that a bounded d...
Article
Electricity load prediction is of great significance to the development of the power market and stable operation of power systems. In recent years, scholars in this field have only considered point forecasting, which ignores the inevitable prediction bias and uncertain information. To fill this gap, this study proposes an interval prediction system...
Article
This study proposes an approach to the construction of granular models directly based on information granules expressed both in input and output spaces. Associating these information granules, the constructed granular models come in the framework of three layers networks: input granules, an inference scheme and output granules. The proposed approac...
Article
This work deals with the language-based opacity verification and enforcement problems in discrete event systems modeled with labeled Petri nets. Opacity is a security property that relates to privacy protection by hiding secret information of a system from an external observer called an “intruder”. A secret can be a subset of a system's language. I...
Article
This paper addresses a distributed lot-streaming permutation flow shop scheduling problem that has various applications in real-life manufacturing systems. We aim to optimally assign jobs to multiple distributed factories and sequence them to minimize the maximum completion time (Makespan). A mathematic model is first developed to describe the cons...
Article
In this paper, a diagnosis problem of discrete event systems (DESs) is considered, including fault pattern detection and diagnosability. A fault pattern in a DES is modeled by an automaton that represents the occurrence of complex faults, i.e., the language of the automaton is the objective to be diagnosed. To solve the problem of fault pattern det...
Article
Recently, in semiconductor manufacturing, cluster tools have to process multiple wafer types concurrently due to product customization. Different wafer types may have different processing routes, which causes deadlocks and complicates the scheduling problem of cluster tools. This work aims to develop a general method to resolve the scheduling probl...
Article
Designing effective and efficient classifiers is a challenging task given the facts that data may exhibit different geometric structures and complex intrarelationships may exist within data. As a fundamental component of granular computing, information granules play a key role in human cognition. Therefore, it is of great interest to develop classi...
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The problem of state estimation in the setting of partially-observed discrete event systems subject to cyber attacks is considered. An operator observes a plant through a natural projection that hides the occurrence of certain events. The objective of the operator is that of estimating the current state of the system. The observation is corrupted b...
Article
In this paper, we investigate multi-agent discrete-event systems with partial observation. The agents can be divided into several groups in each of which the agents have identical (isomorphic) state transition structures, and can thus be relabeled into the same template. Based on the template a scalable supervisor whose state size and computational...
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G-images refer to image data defined on irregular graph domains. This work elaborates on a similarity-preserving Fuzzy C-Means (FCM) algorithm for G-image segmentation and aims to develop techniques and tools for segmenting G-images. To preserve the membership similarity between an arbitrary image pixel and its neighbors, a Kullback-Leibler diverge...
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In this paper, we develop a residual-sparse Fuzzy C-Means (FCM) algorithm for image segmentation, which furthers FCM's robustness by realizing the favorable estimation of the residual (e.g., unknown noise) between an observed image and its ideal version (noise-free image). To achieve a sound trade-off between detail preservation and noise suppressi...
Article
Serious air pollution poses destructive effects on environmental safety and human health, which is a public threat worldwide. Therefore, it is important to develop a reliable air pollution forecasting system to monitor air quality in advance. Most of the existing researches lack data feature mining and uncertainty analyses of predictions, leading t...
Article
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Petri nets, as an effective mathematical tool, have been intensively used in modeling and analyzing automated manufacturing systems (AMSs). Many deadlock control policies have been proposed for AMSs, but most of them assume that resources never fail during product processing. However, resource failures may happen in a real world, which may invalida...
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Due to the limitations of data transfer technologies, existing studies on urban traffic control mainly focused on isolated dimension control such as traffic signal control or vehicle route guidance to alleviate traffic congestion. However, in real traffic, the distribution of traffic flow is the result of multiple dimensions whose future state is i...
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Energy consumption prediction of buildings has drawn attention in the related literature since it is very complex and affected by various factors. Hence, a challenging work is accurately estimating the energy consumption of buildings and improving its efficiency. Therefore, effective energy management and energy consumption forecasting are now beco...
Article
In this paper, we study the verification and enforcement problems of strong infinite-step opacity and k-step opacity for partially observed discrete-event systems modeled by finite state automata. Strong infinite-step opacity is a property such that the visit of a secret state cannot be inferred by an intruder at any instance along the entire obser...
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Reducing energy consumption, regardless of fuel or electricity, of ground vehicles is a paramount pursuit in academia and industry. Current research concentrates exclusively on the improvement of the vehicle, but accepts the road conditions as external influences. The innovation of this article is to consider the road conditions, particularly the g...
Article
This study contributes to a development of granular models, which are realized through an aggregation of the outputs produced by numeric models formed at a lower level of hierarchy. The aim is to form a consensus through adjusting local sources of knowledge such that the granular outputs could reflect and quantify the diversity of local knowledge....
Article
Accurate hourly PM2.5 concentration prediction plays a key role in air quality monitoring and controlling system, especially when severe haze occurs frequently. A PM2.5 hourly prediction system is developed in this paper, based on an advanced data processing strategy, an effective feature selection technology and a novel optimization algorithm. Fir...
Article
Opacity is a confidentiality property that holds if certain secret behavior of a system, typically represented by a predicate, cannot be revealed under any system evolution. Among other proposed methodologies, when opacity is violated, it can be enforced using insertion mechanisms, i.e., by inserting symbols before an actual system output (in real...
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Deadlocks are a highly undesirable situation in flexible manufacturing systems (FMSs). This article presents a direct and novel method to detect such markings by constructing the resource flow graph of a Petri net that models an FMS and to recover such markings by adding a set of recovery transitions. First, an algorithm is developed to build a new...
Article
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To ensure wafer quality, engineers have to impose wafer residency time constraints and chamber cleaning operations on cluster tools; this has been widely used in semiconductor manufacturing. Wafer residency time constraints and chamber cleaning operations make the scheduling problem of cluster tools more challenging. This work aims to solve such a...
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Purpose: The aim of this paper was to build a performance evaluation index system for the combination of medical and old-age care services in pension institutions of China. Methods: A two-stage data envelopment analysis (DEA) is used to evaluate the performance of 30 pension institutions in China. Results: The results show that the two-stage D...
Article
As an effective means to reduce enterprise energy consumption, job-shop scheduling has received extensive attention in the industry. This paper focuses on a real case energy-efficient scheduling problem for aerospace complex components in a flexible job-shop with complex processes. To handle the issues of low production efficiency, high energy cons...
Article
Wind power forecasting is critical to the safe running of the power grid. However, due to the strong intermittence and instability of wind, reliable forecast of wind power remains a significant difficulty. In this study, a novel multivariable machine learning hybrid prediction system that incorporates data preprocessing, prediction, and multi-objec...
Preprint
Opacity, as an important property in information-flow security, characterizes the ability of a system to keep some secret information from an intruder. In discrete-event systems, based on a standard setting in which an intruder has the complete knowledge of the system's structure, the standard versions of current-state opacity and initial-state opa...
Article
Timed extended reachability graphs (TERG) of time Petri nets abstract the temporal specifications and represent the feasible trajectories under the earliest firing policy. One drawback of such graphs is the rapid increase in the number of states with respect to time specifications. For this reason, approximations of TERG that remove some states hav...
Article
This paper studies the marking diagnosability verification problem in labeled Petri nets. Marking diagnosability is a property implying the fact that a plant Petri net has ever reached a pre-defined set of faulty markings can be detected in a finite number of future steps. We first show that the conventional basis-reachability-graph-based methods c...