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1.
This paper deals with the determination of seat allocations for a rail booking system. It is assumed that demand for each trip in the network can be divided into two segments, namely a full fare segment and a discounted fare segment. A constrained nonlinear integer programming model is formulated to deal with this problem. The purpose of this paper is to develop an efficient heuristic approach to develop the booking limits for all ticket types in the railway network. The solutions obtained by the heuristic approach are compared with those found by the Lingo software and the DICOPT solver. Numerical results show that the proposed heuristic approach only require a small number of CPU time to obtain superior solutions. 相似文献
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Safety and comfort analysis of a 3-D vehicle model with optimal non-linear active seat suspension 总被引:1,自引:0,他引:1
A generalized nonlinear model is formulated for the dynamic analysis of suspension seats with passive, semi-active and active dampers. The model incorporates coulomb friction due to suspension linkages and bushings, forces arising from interactions with the elastic limit stops, a linear suspension spring and nonlinear damping force for passive, semi-active and active dampers, while the contribution due to biodynamics of the human operator is considered to be negligible. The semi-active and active dampers are characterized by force generators in accordance with the control laws based upon suspension mass velocity. Two different suspension seats are experimentally assessed in the laboratory under sinusoidal and random excitations arising from an urban bus, and the measured data is used to demonstrate the validity of the proposed generalized model. The results showed reasonably good agreement between the model results and the measured data. Optimal model parameters are selected using the sequential unconstrained minimization technique with an objective to minimize the acceleration due to vibration transmitted to the occupant mass. The comfort and safety performance characteristics of the optimal suspension seat with semi-active and active dampers are evaluated under both the sinusoidal and random excitations based on the guidelines provided by ISO-2631. From these results, it is concluded that the comfort performance of a suspension seat with semi-active and active dampers can be considerably enhanced by 20–30%. 相似文献
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Tommy Clausen Allan Nordlunde Hjorth Morten Nielsen David Pisinger 《European Journal of Operational Research》2010
In this paper we address the problem of assigning seats in a train for a group of people traveling together. We consider two variants of the problem. One is a special case of two-dimensional knapsack where we consider the train as having fixed size and the objective is to maximize the utilization of the seats in the train. The second is a special case of two-dimensional bin packing where all requests must be accommodated while trying to minimize the number of passenger cars needed. For both variants of the problem we present a number of bounds and develop exact algorithms. Computational results are presented for various instances based on realistic data, and from the packing literature adapted to the problems addressed. 相似文献
4.
The analysis of the sound field of a hall including the effect of audience seats has difficulties in computing time and memory. Although extensive investigations have been conducted for analyzing sound fields, there is scarcely any report dealing with the sound field including this effect. The main cause may be the complex shape and amount of materials of the audience seats. However, there is a possibility that periodical grooved structures like seat rows can be replaced by an appropriate imaginary boundary with an impedance of quasi-local reaction at the top of seats. The purpose of this research is to reduce the calculation load of acoustical analysis by treating the seat rows as an imaginary-impedance boundary which is almost equivalent to the characteristics of audience seats. The SDE filter, which can express excess attenuation caused by seat rows, is proposed and some applications to both the geometrical and wave theoretical methods are presented. To examine the validity of this method, some numerical examples calculated using an image method are discussed in comparison with the measured data. Furthermore, the numerical results of its application to the boundary element method are presented and discussed in terms of its effectiveness and validity. 相似文献
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A multistage stochastic programming approach to airline network revenue management is presented. The objective is to determine
seat protection levels for all itineraries, fare classes, points of sale of the airline network and all dcps of the booking
horizon such that the expected revenue is maximized. While the passenger demand and cancelation rate processes are the stochastic
inputs of the model, the stochastic protection level process represents its output and allows to control the booking process.
The stochastic passenger demand and cancelation rate processes are approximated by a finite number of tree structured scenarios.
The scenario tree is generated from historical data using a stability-based recursive scenario reduction scheme. Numerical
results for a small hub-and-spoke network are reported.
This research is supported by the DFG Research Center Matheon “Mathematics for key technologies” in Berlin. 相似文献
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A 3-DOF analytical model for a tractor seat suspension system is presented in this paper. The response characteristics of the model have been determined using a computer simulation technique. It was observed that vibration transmissibility predicted by this model matched very well with the measured values. In contrast, the values predicted by 1-DOF or 2-DOF models did not match that well. The suspension system having spring constant between 10.726 and 18.957 kN/m and damping co-efficient between 0.665 and 1.099 kNs/m were found to be suitable for Indian tractor seats. Furthermore, the model could be employed as a tool in selection of optimal suspension parameters for any other type of vehicles. 相似文献
10.
《Operations Research Letters》2020,48(3):291-296
To address the discrepancy between dynamic models and industrial practice in airline revenue management, we propose a hybrid model for the multi-leg problem that integrates static and dynamic models. We formulate the problem using a stochastic dynamic program and characterize the optimal booking policy as a switching-curve (surface) type. 相似文献