具有模糊加工时间的Flexible Job-Shop Scheduling问题的研究

采用梯形模糊数来表征柔性生产系统中的时间参数,并在此基础上对具有模糊加工时间的柔性作业车间最小化制造跨度调度问题进行了描述。然后给出了基于粒子群优化的柔性作业车间调度模型。最后通过实例验证了模型的有效性。     

Multinomial distributions applied to random sampling of particulate materials

When sampling a batch consisting of particulate material, the distribution of a sample estimator can be characterized using knowledge about the sample drawing process. With Bernoulli sampling, the number of particles in the sample is binomially distributed. Because this is rarely realized in practice, we propose a sampling design in which the possible samples have a nearly equal mass. Expected values and variances of the sample estimator are calculated. It is shown that the sample estimator becomes identical to the Horvitz–Thompson estimator in the case of a large batch-to-sample mass ratio and a large sample mass. Simulations and experiments were performed to test the theory. Simulations confirm that the round-off error due to the discrete nature of particles is negligible for large sample sizes. Sampling experiments were carried out with a mixture of PolyPropylene (PP) and PolyTetraFluorEthylene (PTFE) spheres suspended in a viscous medium. The measured and theoretical variations are in good agreement.     

Can People Value Protection against Invasive Marine Species? Evidence from a Joint TC–CV Survey in the Netherlands

Harmful algal-bloom species (HABs) are invasiveexotic species that are primarily introduced inNorth European waters through ballast water ofships. Some produce important damages to themarine ecosystem such as the red tides thatcause a massive destruction of marine livingresources, including fish and bottom-livinganimals. Others are responsible for theproduction of thick foams with repellent odorsand the coloration of the beach water, causingimportant damages on beach recreation. Thisarticle reports a monetary valuation study of amarine protection program. This program focuseson the prevention of HABS along the coastlineof the Netherlands. It entails the constructionof a ballast water disposal treatment in theRotterdam harbor and the implementationof a monitoring program of the water quality inthe open sea along the North-Holland beaches.The valuation study is based on a questionnaireundertaken at Zandvoort, a famous Dutchbeach resort. The economic value of the marineprotection program includes non-market benefitsassociated with beach recreation, human healthand marine ecosystem impacts. Both contingent-valuation and travel-cost methods are used.These valuation techniques have not yet beenapplied to value HABs damages. The valuationresults indicate that the protection programmakes sense from an economic perspective aslong as its cost is, in any case, less than 225 millioneuro, and possibly less than 326 million euro, depending on how survey refusals are dealt with.     

基于微粒群算法的配送中心选址研究

作为挖掘现代企业利润源泉的突破口,配送在物流活动中占有举足轻重的地位。多网点配送中心选址是后续物流活动开展的首要条件,对于该问题的研究具有现实意义。由于微粒群算法的普适性、鲁棒性、全局搜索性等特点,在求解复杂问题中能够较好地体现其优越性。结合运筹学中的运输规划的思想,对复杂的数学模型进行了简化,并针对问题的特点构造了求解编码机制。根据文献资料,将其中的仿真数据进行了整合,使得数据具有一定的现实意义,并用微粒群算法进行求解,得到了较好的效果。     

基于粒子群优化的LS-SVM的福建航空物流需求预测

根据福建省过去十几年航空货物发送量的数据,针对航空物流预测的不确定性,将粒子群优化算法和最小二乘支持向量机相结合,采用粒子群优化最小二乘支持向量机的方法来建立模型。并将优化后的最小二乘支持向量机模型应用于福建省航空物流的需求预测中,而后通过仿真对结果进行验证。     

旋液分离器对泥浆的颗粒分离效率和脱水能力

旋液分离器在泥浆处理领域应用广泛,具有颗粒分级和脱水浓缩的功能,底流颗粒粒径大、浓度高,溢流反之,两者粒径的理论界限称为分离粒径(d_C),实际运转时溢流和底流的颗粒分流会非线性地偏离分离粒径,因此实际粒级效率和脱水率的测试和控制对泥浆处理至关重要。依托泥水盾构工程的泥浆处理系统,使用激光粒度分布测试旋流进浆、底流和溢流粒度组成,结合筛析推演计算全段及各粒级效率,并对比宏观测试计算分离效率,分析旋流正常运转时的泥、水和泥浆的分流关系并提出判别方法。结果表明,该测试计算和判定方法在量程范围内快速有效,颗粒分离偏离分离粒径明显;设备参数不变时,平均效率与脱水率间负相关,且不受颗粒性质和测试方法影响,底部扩口等设备调整可实现两者同时增大。     

Inference of Dynamic Generalized Linear Models: On-Line Computation and Appraisal

The purpose of this paper is to provide a critical discussion on real-time estimation of dynamic generalized linear models. We describe and contrast three estimation schemes, the first of which is based on conjugate analysis and linear Bayes methods, the second based on posterior mode estimation, and the third based on sequential Monte Carlo sampling methods, also known as particle filters. For the first scheme, we give a summary of inference components, such as prior/posterior and forecast densities, for the most common response distributions. Considering data of arrivals of tourists in Cyprus, we illustrate the Poisson model, providing a comparative analysis of the above three schemes.     

粒子群优化算法的研究现状与发展概述

粒子群优化算法(PSO)是基于群体智能的一种优化算法。该算法简单易于实现,可调参数少,得到了广泛的研究和飞速发展。介绍了PSO提出的背景、PSO的思想和原理,分析并总结了PSO的优缺点。根据PSO算法研究侧重点的不同,总结了PSO算法的发展现状及特点,分析并展望了PSO还需要完善或继续研究的问题,展望了PSO的研究热点及发展趋势。     

STOCHASTIC LOCAL INTENSITY LOSS MODELS WITH INTERACTING PARTICLE SYSTEMS

It is well known from the work of Schönbucher that the marginal laws of a loss process can be matched by a unit increasing time inhomogeneous Markov process, whose deterministic jump intensity is called local intensity. The stochastic local intensity (SLI) models such as the one proposed by Arnsdorf and Halperin allow to get a stochastic jump intensity while keeping the same marginal laws. These models involve a nonlinear stochastic differential equation (SDE) with jumps. The first contribution of this paper is to prove the existence and uniqueness of such processes. This is made by means of an interacting particle system, whose convergence rate toward the nonlinear SDE is analyzed. Second, this approach provides a powerful way to compute pathwise expectations with the SLI model: we show that the computational cost is roughly the same as a crude Monte Carlo algorithm for standard SDEs.     

中国雾霾成因及治理对策

雾霾天气的成因和治理,不仅是中国政府民众重点关注的话题,更是大气环境科研工作者必须面对的挑战。从颗粒物成分、污染物来源、气象条件以及特殊时期的污染特征分析等多方面对雾霾成因进行了分析论证,并从监测、评价、控制等多角度提出了适合中国国情的雾霾治理对策。