This article shows a composed method for modeling the concurrent execution of working processes in flexible manufacturing systems (FMS) by a special class of Petri nets named Resource Oriented Petri nets (ROPN). Essentially, the type of net comes from the availability of system resources. The analysis of ROPN is used to characterize deadlock situations in terms of full markings for certain structure named PPC. For the sake of preventing the system from deadlocks, a policy is proposed based on a series of restrictions for resource allocation, without considering the presence of unmarked siphons in Process Oriented Petri net (POPN). Finally, a control strategy of deadlock avoidance is designed for ROPN, which is better than other control policy.

Aiming at the issues of smooth transition from IPv4 to IPv6 and interoperability in technical coexistence period about campus network, discussing the technical characteristics of IPv6 protocol, GNS3 and OPNET simulator, combined with the status of weakness of IPv6 technology, lack of IPv6 technology planning and financial support for network upgrade in the vast majority of colleges, adopted the simulation methods to build a network model of IPv4 and IPv6 to achieve the technologies study such as topology design, network configuration and testing, network performance design and evaluation of IPv6 campus network under the low-cost conditions.

Aiming at problems of test, layout and application about campus network and combining with fundamental characteristic, introducing primary technology about transition from IPv4 campus network to IPv6 one, This paper discusses the status of IPv6 support technology and presents basic concept that campus network can be formed Gradually through layout testing network and experimental network; At the same time, in order to offer practical technical reference to favorable upgrading and applying campus network of ordinary universities It also discusses some services and applications about IPv6 campus network.

The optimal scheduling of crude-oil operation in refineries has been studied by various groups during the past decade leading to different mixed integer linear programming or mixed nonlinear programming formulations. This paper presents a new formulation with oil residency time constraint based on single-operation sequencing (SOS). It is different from previous formulations as it considers oil residency time constraint and pipeline transfer and does not require to postulate the number of priority-slots in which operations take place. This model is also based on the representation of a crude-oil scheduling by a single sequence of transfer operations. A simple MILP procedure has been used to solve this model leading to an satisfactory optimal result.

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