Zizhen Zhang

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In today’s global free market, third-party logistics providers (3PLs) are becoming increasingly important. This paper studies a problem faced by a 3PL operating a warehouse in Shanghai, China, under contract with a major manufacturer of children’s clothing based in the United States. At the warehouse, the 3PL receives textile parcel shipments from the(More)
This paper investigates the manpower allocation problem with time windows and job-teaming constraints (MAPTWTC), a practical scheduling and routing problem that tries to synchronize workers’ schedules to complete all tasks. We first provide an integer programming model for the problem and discuss its properties. Next, we show that tree data structure can be(More)
and Applied Analysis 3 transformed into the following nondimensional form: dx dt x 1 − x t − τ1 − xy a1 bx c1y , dy dt y [ δ − β t − τ2 x t − τ2 ] , 1.4 where a1 a/K, c1 cr/α, δ s/r, β sh/α are the non-dimensional parameters and they are positive. The main purpose of this paper is to consider the effect of multiple delays on system 1.4 . The local stability(More)
Most literature on variations of vehicle routing problem assumes that a vehicle is continuously available within the planning horizon. However, in practice, due to the working time regulation, this assumption may not be valid in some applications. In this paper, we study a multiperiod vehicle routing problem with profit (mVRPP), where the goal is to(More)
The split-delivery vehicle routing problem (SDVRP) is a natural extension of the classical vehicle routing problem (VRP) that allows the same customer to be served by more than one vehicle. This problem is a very challenging combinatorial optimization problem and has attracted much academic attention. To solve it, most of the literature articles adopted(More)
This paper introduces a multi-period inspector scheduling problem (MPISP), which is a new variant of the multi-trip vehicle routing problem with time windows (VRPTW). In the MPISP, each inspector is scheduled to perform a route in a given multi-period planning horizon. At the end of each period, each inspector is not required to return to the depot but has(More)
This paper is concerned with a delayed SIRS epidemic model with a nonlinear incidence rate. The main results are given in terms of local stability and Hopf bifurcation. Sufficient conditions for the local stability of the positive equilibrium and existence of Hopf bifurcation are obtained by regarding the time delay as the bifurcation parameter. Further,(More)