基于灰色马尔可夫模型的节能设备故障预测研究

精准预测节能设备故障可以有效节约节能服务公司运营成本,直接关系到节能服务公司的节能项目管理.根据灰色系统理论,将灰色均值GM(1,1)模型与马尔可夫模型融合,通过灰色马尔可夫模型预测节能设备的故障状况.具体而言,首先通过灰色均值GM(1,1)模型预测节能设备的未来故障情况,然后通过马尔可夫状态转移矩阵确定未来节能设备故障的可能状态,最后基于预测值与实际值的比值关系修正预测结果,以实现对节能设备故障次数的精准预测.结果表明灰色马尔可夫模型提高了预测精度,为精准预测节能设备故障提供了一种新思路.     

基于改进灰色GM(1,1)马尔柯夫模型的煤矿事故百万吨死亡率预测

煤矿安全事故预防和控制是煤矿安全评价和决策的基础.灰色预测适合于时间短、数据量少和波动不大的系统对象,而马尔可夫链理论适用于预测随机波动大的动态过程.结合灰色预测GM(1,1)模型和马尔可夫链理论的优点,提出了一种改进的灰色马尔可夫GM(1,1)模型.利用改进的GM(1,1)模型进一步拟合煤矿人因失误事故的发展变化趋势,并以此为基础进行马尔柯夫预测,提高预测效果.以2000-2010年全国煤矿事故百万吨死亡率为例进行了预测分析,结果表明模型既能揭示煤矿人因失误事故百万吨死亡率变化的总体趋势,又能克服随机波动性数据对预测精度的影响,具有较强的工程实用性,并对煤矿人因失误安全事故的预测和控制有一定的实际意义.     

基于改进的灰色马尔可夫链模型的交通事故预测

交通事故预测是交通安全评价、规划和决策的基础.灰色预测适合于数据量少和波动小的系统对象,而马尔可夫链理论适用于预测随机波动大的动态过程.为克服一般灰色马尔可夫链模型运用的转移概率矩阵固定不变而影响预测精度的问题,本文建立了改进的灰色马尔可夫链模型.采用滑动转移概率矩阵方法,去掉最老数据并补充最新数据,从而建立新的一步转移概率矩阵.借助改进的灰色马尔可夫链模型,对全国2002-2004年交通事故10万人口死亡率进行了预测分析.结果表明,改进的灰色马尔可夫链模型比一般灰色马尔可夫链模型的预测范围更准确,预测精度更高.     

基于灰色-马尔可夫链模型的危险化学品事故预测

根据危险化学品伤亡事故的发生受多种灰色因素影响,并且具有较大的随机波动性的特点,提出了运用灰色-马尔可夫链预测模型对危险化学品死亡人数进行预测分析.结果表明,所建立的灰色-马尔可夫链预测模型既能反映死亡人数变化的总体趋势,又能体现数据的波动性特点,其预测精度高于GM(1,1)模型的预测精度,可以较好地应用于危险化学品事故的预测,为该行业的安全管理提供准确的理论依据.     

奥运会男子现代五项前三名成绩的灰色马尔可夫链预测模型的研究

研究了奥运会男子现代五项前三名成绩的预测模型.将灰色GM(1,1)模型和马尔可夫模型结合,构建了灰色马尔可夫预测模型.对奥运会男子现代五项前三名成绩趋势进行了预测,给出了第30届奥运会男子现代五项前三名成绩的预测结果,并大大提高了预测精度.     

基于灰色加权马尔可夫链的移动通信市场预测

在传统的用灰色预测模型预测的方法基础上,建立了灰色加权马尔可夫链模型.以中国移动通信市场预测作为实例,介绍了使用这种模型的方法与步骤.灰色加权马尔可夫链模型既考虑了从时间序列中挖掘数据的演变规律,又通过规范化各阶自相关系数为权重,用加权的马尔可夫转移概率矩阵的变换,考虑数据的随机波动,具有严密的科学性,能较好地应用于中国移动通信市场的预测.     

基于灰色马尔可夫预测模型的农村人均收入预测

以武汉市农村人均收入为样本,将灰色预测模型和马尔可夫链预测模型相结合,通过对比预测的数据信息与实际数据信息差距,对2011年和2012年武汉市农村人均收入进行了预测计算.根据相关模拟检验与残差修正,灰色马尔可夫链可视为农村人均收入预测的可行且有效的方法.结果显示,单纯地运用灰色模型,预测值与实际值的误差均值是0.687%;通过马尔可夫链模型的二次模拟得到的误差明显减小.     

基于新陈代谢灰色预测模型的西安市电力需求量的预测

选取西安市2010-2017年的总用电量数据,建立了灰色GM(1,1)模型,对西安市全年电力需求量进行预测.经检验,模型具有较高的精度.进一步通过建立新陈代谢GM(1,1)模型对西安市未来5年的全年电力需求量进行预测,为西安市的电力发展提供科学决策依据.     

销量预测的相对误差马尔柯夫链模糊修正模型研究

在销量预测的改进型灰色预测GM(1,1)模型中,针对传统的相对误差修正的马尔柯夫链预测法,在相对误差微小变化的情况下,存在状态跃变的不合理性,提出应用马尔柯夫链模糊模型的方法.并开展实证研究,得出改进的销量预测值为103.5095万箱的结论.     

基于灰色马尔可夫链模型的人口预测

将灰色预测模型和马尔可夫链预测相结合,将其应用到人口预测中,并依据南京市历年总人口数据进行计算,可以比较准确地预测2008年的户籍人口数,验证了其有效性;同时由模型可以预测2010年,2011年南京户籍人口数以做参考用,灰色马尔可夫链可视为人口预测的可行且有效的方法。     

Relief inventory modelling with stochastic lead-time and demand

The irregular demand and communication network disruption that are characteristics of situations demanding humanitarian logistics, particularly after large-scale earthquakes, present a unique challenge for relief inventory modelling. However, there are few quantitative inventory models in humanitarian logistics, and assumptions inherent in commercial logistics naturally have little applicability to humanitarian logistics. This paper develops a humanitarian disaster relief inventory model that assumes a uniformly distributed function in both lead-time and demand parameters, which is appropriate considering the limited historical data on relief operation. Furthermore, this paper presents different combinations of lead-time and demand scenarios to demonstrate the variability of the model. This is followed by the discussion of a case study wherein the decision variables are evaluated and sensitivity analysis is performed. The results reveal the presence of a unique reorder level in the inventory wherever the order quantity is insensitive to some lead-time demand values, providing valuable direction for humanitarian relief planning efforts and future research.     

考虑需求不确定的多级应急物流设施选址研究

为了对急物流设施选址问题进行合理的研究,建立了包含配送中心、配送点和需求点的多级应急物流网络。基于应急物资需求特点,使用三角模糊数表示应急物资需求的不确定性,同时考虑应急救援成本和应急救援时间两个目标,建立了应急物流设施选址模型。采用去模糊化方法将三角模糊数转化为确定数,利用成本和时间的单目标的最优结果将多目标转化为相对值,再对时间和成本目标进行加权处理,既消除了不同目标之间的单位及数量级差异,还可以进行动态调整。设计了遗传算法对模型进行求解,通过实际算例表明了模型和算法可以有效地解决应急物流设施选址问题。     

Markov-modulated风险模型破产前最大盈余额与破产赤字的联合分布

应用逐段决定马尔可夫过程理论及补充变量技巧,使Markov-modulated风险过程成为齐次强马尔可夫过程,然后利用强马氏性及首达时间分布给出了其破产前最大盈余额与破产赤字的联合分布.     

考虑平台竞争的众包物流社会配送服务最优定价策略

基于互联网的众包物流服务平台共享社会闲置人力资源,为电子商务O2O提供最后一公里配送服务。通过配送服务的动态定价来调控众包物流的社会配送供应能力,成为优化众包物流平台运营的重要手段。在众包物流平台激烈的竞争环境下,考虑到众包物流社会化配送供应能力的不确定性,采用动态优化理论,建立平台价格竞争下众包物流社会配送服务最优定价模型。运用汉密尔顿函数求解社会配送服务最优价格,研究众包物流社会配送服务供应能力随着价格变化的规律,进一步,分析众包物流平台竞争对最优价格变化规律的影响。数值仿真结果表明,众包物流社会配送服务价格增长率随着平台竞争的加剧而增加,可以有效调控众包物流服务的供应与需求平衡,优化众包物流平台的期望收益。     

(s, S) Inventory systems with lost sales and Markov renewal demands

In the study of stochastic inventory systems it is generally assumed that the demand epochs are renewable in nature. The present paper deals with a single-item (s, S) inventory model with a finite number of different types of demands, in which the demand epochs form a Markov renewal process. The lead times are exponentially distributed and the demands that occur during stockout periods are not backordered. For this model the transient and limiting inventory level distributions are computed. Also the theory of point processes is used to obtain the mean reorder and shortage rates and their limiting values. For the special case of renewal demands, the problem of minimizing the long-run expected cost rate is analysed.     

Downward migration credit risk problem: a non-homogeneous backward semi-Markov reliability approach

International organizations evaluate credit risk and rank firms according to risk by assigning them a ‘rating’. The time evolution of a rating can be studied by means of Markov models. Some papers have outlined the problem pertaining to the unsuitable fitting of Markov processes in a credit risk environment. This paper presents a model that overcomes the problems given by the Markov rating models. It includes non-homogeneity, the downward problem and the randomness of time in the transitions of states, thus making it possible to consider the duration inside a state in a complete way. In this paper, both, the transient and asymptotic analyses are presented. The asymptotic analysis is performed by using a mono-unireducible topological structure. Moreover, a real data application is conducted using the historical database of Standard & Poor’s as the source.     

基于GSPN的实施延迟策略生产系统建模与性能分析

延迟策略是协调市场需求变化的绝对性和生产系统相对稳定性矛盾的一个重要战略手段。为分析实施延迟策略生产系统的性能,利用随机广义Petri-net(GSPN)的建模分析方法,并根据GSPN与马尔科夫链的同构关系,将GSPN模型转化成为等价的马尔科夫链模型。通过马尔科夫链及相关数学方法获得实施延迟策略生产系统的主要性能指标。该方法不仅可以分析实施延迟策略生产系统的整体性能,而且能够对系统的各个环节运作效率做出定量分析。最后,通过算例分析验证了该方法的科学性与有效性,丰富了延迟策略研究方面的方法理论。     

随机需求下物流服务供应链订购策略研究

针对由单个物流服务提供商和集成商组成的物流服务供应链,基于集中化模式、纳什博弈模式和Stackelberg博弈模式三种典型模式,考虑市场需求随机且受服务质量缺陷承诺水平的影响,探讨物流服务供应链的订购与质量缺陷承诺策略问题。通过分析发现:物流服务质量缺陷承诺水平随着市场需求弹性系数的增加而递减,但其受物流服务集成商观测水平的影响却因合作模式不同而变化不一致;集中化模式下的物流服务订购量随着物流服务集成商观测水平或市场需求弹性系数的增大而递减,但在其他两种合作模式下物流服务订购量随着物流服务集成商观测水平或市场需求弹性系数的增加而增加;在三种模式下,物流服务供应链的整体利润随着市场需求弹性系数的增加而递减,但其受物流服务集成商观测水平的影响却因合作模式不同而变化不一致。     

Perfect simulation of processes with long memory: A “coupling into and from the past” algorithm

We describe a new algorithm for the perfect simulation of variable length Markov chains and random systems with perfect connections. This algorithm, which generalizes Propp and Wilson's simulation scheme, is based on the idea of coupling into and from the past. It improves on existing algorithms by relaxing the conditions on the kernel and by accelerating convergence, even in the simple case of finite order Markov chains. Although chains of variable or infinite order have been widely investigated for decades, their use in applied probability, from information theory to bio‐informatics and linguistics, has recently led to considerable renewed interest. © 2014 Wiley Periodicals, Inc. Random Struct. Alg., 46, 300–319, 2015     

Experimenting with the Coxian Phase-Type Distribution to Uncover Suitable Fits

In the past few decades, Coxian phase-type distributions have become increasingly more popular as a means of representing survival times. In healthcare, they are considered suitable for modelling the length of stay of patients in hospital and more recently for modelling the patient waiting times in Accident and Emergency Departments. The Coxian phase-type distribution has not only been shown to provide a good representation of real survival data, but its interpretation seems reasonably initiative to the medical experts. The drawback, however, is fitting the distribution to the data. There have been many attempts at accurately estimating the Coxian phase-type parameters. This paper wishes to examine the most promising of the approaches reported in the literature to determine the most accurate. Three performance measures are introduced to assess the fitting process of the algorithms along with the likelihood values and AIC to examine the goodness of fit and complexity of the model. Previous research suggests that the fitting process is strongly influenced by the initial parameter estimates and the data itself being quite variable. To overcome this, one experiment in this research paper will use the same initial parameter values for each estimation and perform the fits on the data simulated from a Coxian phase-type distribution with known parameters.