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Search Results: 1 - 10 of 25743 matches for " Wenming Cheng "
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Particle Swarm Optimization for Gantry Crane Scheduling with Interference Constraints
Peng Guo,Wenming Cheng,Jian Liang
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: This study investigates the problem of scheduling gantry cranes, which are the main handling equipment in railway container terminals. Since the gantry cranes share two common tracks, some interference constraints are considered for the scheduling problem. The scheduling problem is formulated as an integer programming model. In the view of the high computational complexity, a Particle Swarm Optimization (PSO) algorithm is proposed. The effectiveness of the PSO algorithm is evaluated by comparing its results to traditional genetic algorithm and CPLEX on some random instances. Experimental results show that the PSO algorithm reports better quality solution in a short time on larger problem instances.
Parallel machine scheduling with step deteriorating jobs and setup times by a hybrid discrete cuckoo search algorithm
Peng Guo,Wenming Cheng,Yi Wang
Mathematics , 2013,
Abstract: This article considers the parallel machine scheduling problem with step-deteriorating jobs and sequence-dependent setup times. The objective is to minimize the total tardiness by determining the allocation and sequence of jobs on identical parallel machines. In this problem, the processing time of each job is a step function dependent upon its starting time. An individual extended time is penalized when the starting time of a job is later than a specific deterioration date. The possibility of deterioration of a job makes the parallel machine scheduling problem more challenging than ordinary ones. A mixed integer programming model for the optimal solution is derived. Due to its NP-hard nature, a hybrid discrete cuckoo search algorithm is proposed to solve this problem. In order to generate a good initial swarm, a modified heuristic named the MBHG is incorporated into the initialization of population. Several discrete operators are proposed in the random walk of L\'{e}vy Flights and the crossover search. Moreover, a local search procedure based on variable neighborhood descent is integrated into the algorithm as a hybrid strategy in order to improve the quality of elite solutions. Computational experiments are executed on two sets of randomly generated test instances. The results show that the proposed hybrid algorithm can yield better solutions in comparison with the commercial solver CPLEX with one hour time limit, discrete cuckoo search algorithm and the existing variable neighborhood search algorithm.
Scheduling step-deteriorating jobs to minimize the total weighted tardiness on a single machine
Peng Guo,Wenming Cheng,Yi Wang
Mathematics , 2014,
Abstract: This paper addresses the scheduling problem of minimizing the total weighted tardiness on a single machine with step-deteriorating jobs. With the assumption of deterioration, the job processing times are modeled by step functions of job starting times and pre-specified job deteriorating dates. The introduction of step-deteriorating jobs makes a single machine total weighted tardiness problem more intractable. The computational complexity of this problem under consideration was not determined. In this study, it is firstly proved to be strongly NP-hard. Then a mixed integer programming model is derived for solving the problem instances optimally. In order to tackle large-sized problems, seven dispatching heuristic procedures are developed for near-optimal solutions. Meanwhile, the solutions delivered by the proposed heuristic are further improved by a pair-wise swap movement. Computational results are presented to reveal the performance of all proposed approaches.
Variable Neighborhood Search for Parallel Machines Scheduling Problem with Step Deteriorating Jobs
Wenming Cheng,Peng Guo,Zeqiang Zhang,Ming Zeng,Jian Liang
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/928312
Abstract: In many real scheduling environments, a job processed later needs longer time than the same job when it starts earlier. This phenomenon is known as scheduling with deteriorating jobs to many industrial applications. In this paper, we study a scheduling problem of minimizing the total completion time on identical parallel machines where the processing time of a job is a step function of its starting time and a deteriorating date that is individual to all jobs. Firstly, a mixed integer programming model is presented for the problem. And then, a modified weight-combination search algorithm and a variable neighborhood search are employed to yield optimal or near-optimal schedule. To evaluate the performance of the proposed algorithms, computational experiments are performed on randomly generated test instances. Finally, computational results show that the proposed approaches obtain near-optimal solutions in a reasonable computational time even for large-sized problems.
Intersection-Aware Channel Assignment and Routing in Multi-Channel Multi-Hop Wireless Networks with a Single Transceiver
Huang Chuanhe,Cheng Yong,Yang Ling,Shi Wenming,Zhou Hao
International Journal of Distributed Sensor Networks , 2009, DOI: 10.1080/15501320802520563
Abstract: This article proposes an intersection-aware channel assignment and routing protocol for wireless ad hoc networks with a single transceiver. This protocol increases the network capacity of an IEEE 802.11 network by exploiting frequency diversity. Using the proposed protocol, multiple communications can simultaneously take place in a region without interfering with each other. However, it must avoid a multi-channel hidden terminal problem for designing channel assignment and routing protocol. This paper considers issues regarding multiple channels at the network layer, assuming a single channel MAC protocol such as IEEE 802.11 DCF. Also, the proposed protocol assumes that each node in the network is equipped with a single transceiver. This set of assumptions is very practical, because most devices have a single wireless card implementing the IEEE 802.11 DCF protocol. Each node uses modular exponentiation congruence to represent the channel schedule, which assures that each pair of nodes has common channels for communication in every cycle. Each node switches across channels in such a manner that each pair of nodes works on the same channel when they desire to communicate; otherwise they work on a different channel, and hence do not interfere with each other. However, for the intersecting node, there is no benefit in using single radio multiple channels since the capacity around the intersection node can at most be O (W), W is the link capacity, regardless of the number of channels. The protocol lets the intersecting node always work on the same channel whereas the nonintersecting node can work on different channels.
Experimental Research on Hydrogen and Hydrocarbon Fuel Ignition for Scramjet at Ma=4
Zhang Wanzhou,Le Jialing,Yang Shunhua,Cheng Wenming
Modern Applied Science , 2013, DOI: 10.5539/mas.v7n3p56
Abstract: Ignition experiments of Hydrogen and Ethylene were performed on direct-connected pulse combustion facility. Air stagnation temperatures were 900 K and stagnation pressures were 0.8 MPa, the entrance Mach number was approximate 2.0 provided by a two-dimension nozzle. The experimental results indicate that: (1) Hydrogen self-ignition won’t occur at stagnation 935 K when it is injected upstream the cavity in this combustor model. But with low input power igniter, hydrogen can be ignited reliably. (2) Ethylene cannot be ignited with igniter only even at high igniter power. Under the assistant of both igniter and pilot Hydrogen, Ethylene can be ignited reliably and maintain stable combustion after the igniter and pilot hydrogen completely turned off. (3) The lowest equivalence ratio of pilot hydrogen for successful ethylene ignition is 0.05 below that ignition will fail. (4) When pilot hydrogen and igniters were both employed for ignition, the function of igniter is to ignite the hydrogen and the input power of igniter has no influence on ignition performance.
Pointwise Approximation Theorems for Combinations of Bernstein Polynomials with Inner Singularities  [PDF]
Wenming Lu, Lin Zhang
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.24047
Abstract: It is well-known that Bernstein polynomials are very important in studying the characters of smoothness in theory of approximation. A new type of combinations of Bernstein operators are given in [1]. In this paper, we give the Bernstein-Markov inequalities with step-weight functions for combinations of Bernstein polynomials with inner singularities as well as direct and inverse theorems.
柔性梁与带摆动荷载小车的耦合动力学分析
Coupled Dynamics Analysis for a Flexible Beam with a Trolley Subjected to Pendulum Payload

刘华森, 程文明, 尹皓
LIU Huasen
, CHENG Wenming, YIN Hao

- , 2017, DOI: 10.3969/j.issn.0258-2724.2017.02.025
Abstract: 起重机桥架结构的振动以及荷载的摆动会使桥架结构产生疲劳损伤并影响荷载的精确定位。基于荷载、起重小车组成的椭圆摆与移动质量通过桥梁模型,起重机柔性梁与带摆动荷载的移动小车多体刚柔耦合动力学系统,并采用拉格朗日方程推导了耦合系统的运动微分方程组。采用Newmark-β逐步积分方法进行数值求解,分析了起重小车的运动速度、荷载质量等参数对桥架结构振动以及荷载摆动的影响。研究结果表明:起重小车的运行速度会影响桥架结构的振型,桥架结构的最大振动幅度与荷载质量成正比;耦合系统桥架结构中点的挠度比采用ANSYS软件计算的静挠度增大4%;荷载的摆动导致起重小车的驱动力与驱动功率周期性地改变,起重小车驱动力以及驱动功率变化的幅度范围正相关于起重小车的加速度值。
: The vibration of the crane beam and the residual swing of the payload cause fatigue damage of crane and affect the precise positioning of the payload. In this paper, a crane flexible beam with a moving trolley subjected to pendulum payload multibody coupled dynamic system was set up based on an elliptical pendulum constituted by payload with trolley and moving mass passing a bridge model. The differential equations of motions of the coupled system were deduced based on Lagrange equation. The numerical solution was derived by using the Newmark-β step-by-step integration method. The effects of the crane speed and the payload mass on the vibration of the beam and the load swing were analyzed. Numerical analysis results indicate that the crane speed affects the vibration mode of the beam overhead crane, and vibration amplitude is proportional to the mass of payload. The bend at the beam midpoint is 4% larger than the results calculated by ANSYS. The swing of payload leads to periodic changes of the driving force and driving power of the overhead crane. The payload acceleration is positively related to the crane driving force and driving power range
Central limit theorem for the occupation time of catalytic super-Brownian motion
Wenming Hong
Chinese Science Bulletin , 1998, DOI: 10.1007/BF03183501
Abstract: The catalytic super-Brownian motion has been considered. If both the catalytic medium process 2 and CSBM started with Lebesgue measure λ, the central limit theorem for occupation time of CSBM has been obtained in dimension 3 forP λ -α.s.2.
John-Nirenberg Type Inequalities for the Morrey-Campanato Spaces
Wenming Li
Journal of Inequalities and Applications , 2008, DOI: 10.1155/2008/239414
Abstract: We give John-Nirenberg type inequalities for the Morrey-Campanato spaces on ¢ n.
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