GuanJun Liu - Academia.edu (original) (raw)

Papers by GuanJun Liu

Fundamenta Informaticae

ABSTRACT Classical workflow nets WF-nets for short are an important subclass of Petri nets that a... more ABSTRACT Classical workflow nets WF-nets for short are an important subclass of Petri nets that are widely used to model and analyze workflow systems. Soundness is a crucial property of workflow systems and guarantees that these systems are deadlock-free and bounded. Aalst et al. proved that the soundness problem is decidable for WF-nets and can be polynomially solvable for free-choice WF-nets. This paper proves that the soundness problem is PSPACE-hard for WF-nets. Furthermore, it is proven that the soundness problem is PSPACE-complete for bounded WF-nets. Based on the above conclusion, it is derived that the soundness problem is also PSPACE-complete for bounded WF-nets with reset or inhibitor arcs ReWF-nets and InWF-nets for short, resp.. ReWF-and InWF-nets are two extensions to WF-nets and their soundness problems were proven by Aalst et al. to be undecidable. Additionally, we prove that the soundness problem is co-NP-hard for asymmetric-choice WF-nets that are a larger class and can model more cases of interaction and resource allocation than free-choice ones.

Information Processing Letters, Jul 1, 2009

This paper first proves that each minimal siphon in a weakly persistent net is a trap if its pre-... more This paper first proves that each minimal siphon in a weakly persistent net is a trap if its pre-set is nonempty. Therefore, each minimal siphon contains a marked trap if a weakly persistent net is live for an initial marking. Next, it is proved that the condition, each minimal siphon contains a marked trap, is both necessary and sufficient for the liveness of weakly persistent nets if these nets additionally satisfy the asymmetric choice property or the intrinsic fairness.

Ieee Transactions on Automation Science and Engineering, 2010

Journal of Information Science and Engineering, 2009

The International Journal of Advanced Manufacturing Technology, 2009

In this paper a novel policy is proposed to solve the deadlock problem in a class of flexible man... more In this paper a novel policy is proposed to solve the deadlock problem in a class of flexible manufacturing systems based on the notion that each shared buffer is partitioned into parts to store different types of products, respectively. A subclass of Petri nets called resource-shared net with buffers (RSNB) is defined. An RSNB is constructed by synthesizing some marked graphs, and each marked graph can model the process of manufacturing one type of product. RSNB cannot only model the concurrent execution of manufacturing processes, but also ensure that the modeled system is live. The process of constructing RSNB is described in detail, and a minimal siphon based necessary and sufficient condition is provided to characterize the liveness of RSNB.

IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 2013

ABSTRACT

This paper presents a class of Petri nets, process nets with channels (PNCs) that can model some ... more This paper presents a class of Petri nets, process nets with channels (PNCs) that can model some types of concurrent systems in two aspects: process and interaction. Its significance lies in offering efficient analysis and verification methods for these systems. PNCs belong to the class of extended free choice nets. This paper establishes the conditions to examine their liveness, reversibility, and reachability based on their structural characteristics. Siphons, traps, and a state equation are used to describe these conditions such that analysis techniques based on reachability graphs and siphon enumeration are avoided. A polynomial-time algorithm is presented for the liveness analysis, and an effective method is also given to decide the reachability. A real-world example is used to illustrate the application of PNCs.

The conventional model of maintenance logistics is almost based on hierarchical structure, which ... more The conventional model of maintenance logistics is almost based on hierarchical structure, which exchanges information and shares resources depending on chain of control. It is not adaptive for requirement of sustaining all scope of operation and maintenance of equipments, and the research and development of an innovative maintenance model is necessary, which is evolved from chain-structure to networks-structure due to nonlinearity and complexity of maintenance support behavior. In this paper the organizational model and information model of maintenance support behavior are outlined, a topology structure of maintenance support networks is described, an approach to model maintenance logistics with three-level logistics architecture is presented using undirected unweighted networks, and then the performance metrics of complex logistics networks, such as average path length, clustering coefficient and degree distribution, is analyzed with Matlab based on adjacency matrix. Additional links between nodes of networks are evolved with small-world principle, and the performance metrics along with linkage probability are illustrated, which can be employed to optimize maintenance organizational and support networks.

Journal of Industrial Textiles, 2008

With the innovation of spinning method and Lycra® fiber, wool elastic core-spun yarn is applied f... more With the innovation of spinning method and Lycra® fiber, wool elastic core-spun yarn is applied for more industrial end-uses, which make it meaningful to study the mechanical property of wool/spandex core-spun yarn. Tensile property of staple yarns has been studied by many researchers. However, no research is reported on the tensile property of elastic core-spun yarn. In this paper, a