物流园区物流量灰色马尔可夫预测模型

物流量是物流园区规划、建设和管理的一项重要统计数据。结合灰色理论和马尔可夫链的特点,建立灰色马尔可夫预测模型,对某物流园区的物流量进行预测。首先,根据历史统计数据建立灰色预测模型,并对模型进行精度检验。再根据灰色模型预测误差将系统划分为3个状态,确定马尔可夫状态转移矩阵,建立灰色马尔可夫预测模型,并预测物流园区的物流量。将预测结果与灰色模型对比,结果表明,建立的灰色马尔可夫预测模型可用于物流园区物流量预测,且其预测精度较高。     

一种简易预测模型的应用

预测是各个部门制订工作计划的一项基本工作 ,是指对未来活动的科学推测。预测的正确与否取决于对预测模型的分析。而预测的方法有“最小二乘法”、“卡尔曼滤波法”、“最小方差预测法”、“指数平滑法”等等 ,但是以上方法的特点是模型复杂 ,计算工作量大。据此介绍了两种比较简单的预测模型即“灰色预测模型”及“递推及残差识别预测模型” ,其结果是一致的     

双向差分灰色模型在路面性能预测中的应用

利用双向差分灰色模型,建立高速公路沥青路面使用性能灰色预测模型,并分析模型的预测精度。结合该模型对某高速公路使用性能的指标进行预测,根据预测结果与路面实际检测数据的对比,分析模型预测结果的合理性和该指标的发展,讨论双向差分灰色模型在路面使用性能预测中的适用性。     

基于残差修正GM(1,1)模型的银川市空气质量预测分析

选取2013～2017年影响银川市环境空气质量的六种主要污染物浓度值,建立GM(1,1)预测模型,对精度检验结果为基本合格和不合格模型进行残差修正,得到了残差修正GM(1,1)预测模型,其精度检验为优。2018～2020年污染物浓度预测值显示CO和O_3浓度值有增加的趋势,建议相应部门做好预防CO和O_3浓度值增加的措施。     

林分断面积组合预测模型权重确定的比较

引入组合预测方法以提高林分断面积预测的精度及2类模型(林分水平模型和单木水平模型)预测林分断面积的兼容性。组合预测法能够充分利用各单个模型的有效信息,从而提高预测精度,而单个模型权重的选取对提高组合预测法的精度至关重要。本研究基于北京山区油松连续清查数据,利用误差平方和法、方差协方差法和最优加权法确定林分断面积组合预测模型的权重。结果表明:组合预测法能够提高预测精度,同时利用最优加权法所建立的林分断面积组合预测模型其预测精度最高,方差协方差法次之,误差平方和法预测精度最低。     

基于灰色神经网络的辽宁省生鲜物流需求预测

为准确预测生鲜产品物流需求量，提出了一种基于灰色GM(1,1)模型和BP神经网络的组合预测模型。首先构建了生鲜物流需求指标体系，然后分别利用传统灰色预测模型GM(1,1)和BP神经网络做单一预测，最后将2个模型进行加权做组合预测。选取辽宁省作为实例，通过MATLAB软件进行辽宁省生鲜产品的物流需求预测，结果表明：与2个单一的预测模型相比，灰色神经网络模型拥有更高的预测精度，因此选择组合预测模型对辽宁省未来5年生鲜产品需求量进行预测，为辽宁省生鲜物流管理的战略部署提供一定的参考。     

近红外光谱数据建立相思树制浆得率预测模型

用近红外光谱数据建立了相思树制浆得率的预测模型：将近红外光谱数据按波长进行分组,然后使用拟合方法建立了10个子数学模型,最后通过计算子模型制浆得率预测值的加权平均值给出了预测制浆得率的公式。预测结果表明,用近红外光谱数据建立的预测模型可用于快速估算相思树的制浆得率,其建模方法有望用于其他速生纸浆材制浆得率的预测。     

基于灰色马尔可夫模型的黑龙江省对日贸易额预测

为了提高黑龙江省对日贸易的预测精度,对灰色系统和马尔科夫理论进行研究分析,建立黑龙江省对日贸易额灰色马尔可夫预测模型。该模型融合灰色系统与马尔科夫理论的特点,可以大大提高预测精度。在实例应用中,建立贸易额GM（1,1）灰色预测模型,在获得预测值和残差检验的基础上,将原始数据划分为3个状态,计算状态转移概率,利用灰区间中位数建立贸易额灰色马尔可夫预测模型,对黑龙江省对日贸易额进行预测,将预测的结果与GM（1,1）的进行比较,结果表明,灰色马尔可夫预测模型不仅可以预测贸易额,而且其预测精度明显高于GM（1,1）预测。     

昆明主要森林可燃物含水率预测模型的研究

为了探究可燃物含水率的研究方法,以利于森林火灾监测系统的完善,于2016年当地防火期内进行,通过对昆明地区6块样地可燃物含水率的监测,同时收集样地相关的气象因子数据,建立气象要素回归模型,并评估其预测精度。结果表明:在自建模型中,死可燃物的预测模型适用性更好,活可燃物其含水率变化可能并不是单一的只受客观因素的影响,其自身的生命活动也会影响到其含水率的变化,使得含水率的研究更加复杂;坡向对含水率变化的影响并不明显;而对于模型外推,通过有限的20组数据对预测模型进行验证,对于死可燃物普遍表现出不错的适用效果,证明了模型有一定的使用意义。     

基于机器学习算法进行电气设备故障的预测与诊断

城市照明系统是重要的公共基础设施,作为一种电气设备,其在运行过程中有可能出现各种故障,具体可分为配电系统故障和路灯节点故障。为了建立智能化的故障诊断和预测方法,以极限学习机(extreme learning machine, ELM)为基础,利用蒙特卡洛方法和自回归模型对其进行优化,并分别构建了AG-ELM和AR-ELM算法。基于AG-ELM算法诊断路灯节点故障,通过AR-ELM算法预测路灯电气配电系统故障。在性能检测阶段,收集某城市的路灯系统运行数据,检验故障诊断模型的准确率,结果为89.3%,故障预测模型的均方误差仅为0.055 2,说明2种模型都达到了较高的实用性。     

Probability of surface fire spread in Brazilian rainforest fuels from outdoor experimental measurements

This paper describes the development of a logistic model to predict the probability of surface fire spread in Brazilian rainforest fuels from outdoor experimental measurements. Surface fires spread over litter composed mostly of dead leaves and twigs. There were 72 individual outdoor experiments in eighteen sites. The fire propagated in 49% of the experiments. In each experiment, the litter height, litter temperature, unburned litter mass, wet and dry litter mass, soil temperature, wet and dry soil mass, ambient wind velocity, ambient air temperature, ambient air relative humidity and duration of fire spread were measured. Using these data, the rate of fire spread, litter bulk density, litter and soil moisture content, litter load and litter residue fraction were determined. For the sake of analysis, experimental results were classified into two groups: one for which the fire propagated and the other one for which the fire self-extinguished. Analyses of a logistic regression model showed that the relevant parameters for fire propagation are litter height and litter moisture content. Concerning the probability of successful fire propagation, the model showed a true positive rate of 71% and a true negative rate of 84%. The outdoor experiments also served to gather data to improve the understanding of surface fires and to provide input data for future computer simulations.     

灰色系统理论在环境空气质量预测中的应用——以济南市为例

指出了灰色系统理论是由邓聚龙教授于1982年创立的,并在经济、气象、水利、交通运输、环境保护等众多领域得到了广泛应用。该理论体系中灰色预测GM(1,1)模型具有要求数据较少,原理简单有效,结果精度高等特点,适合对空气质量变化的预测。利用山东省济南市2001～2010年环境空气质量监测数据,分析了主要污染物(SO2、NO2和PM10)浓度的年际变化及其原因,并通过对其数据处理,建立了相应的GM(1,1)模型,对济南市未来五年空气质量做出预测。结果表明:在未来5年内,济南市SO2年平均浓度将呈现稳中有降的趋势,NO2和PM10则将呈现略微上升趋势。其中PM10仍是济南市最主要的污染物,是防治的重点。     

Thermal constants of wood during the heating process measured with the laser flash method

The thermal diffusivity, specific heat, and thermal conductivity of 13 species of wood were measured by means of the laser flash method to investigate the thermal properties of wood during the heating process. The temperature ranged from room temperature to 270°C in air or under vacuum. The thermal diffusivity varied little during the heating process up to 240°C. The values in air were larger than those under vacuum. There was a linear relation between the specific heat and the ambient temperature, and the specific heat under vacuum was larger than that in air at high temperature. The thermal conductivity increased with density and the ambient temperature. To discuss the effects of the atmospheric conditions on the thermal constants of wood, a theoretical model of thermal conductivity was proposed and its validity examined, where the wood was assumed to be a uniformly distributed material composed of cell walls and air.Part of this paper was presented at the 47th annual meeting of Japan Wood Research Society at Kochi, April 1997     

Diurnal and seasonal changes in the impact of CO(2) enrichment on assimilation, stomatal conductance and growth in a long-term study of Mangifera indica in the wet-dry tropics of Australia

We studied assimilation, stomatal conductance and growth of Mangifera indica L. saplings during long-term exposure to a CO(2)-enriched atmosphere in the seasonally wet-dry tropics of northern Australia. Grafted saplings of M. indica were planted in the ground in four air-conditioned, sunlit, plastic-covered chambers and exposed to CO(2) at the ambient or an elevated (700 micro mol mol(-1)) concentration for 28 months. Light-saturating assimilation (A(max)), stomatal conductance (g(s)), apparent quantum yield (phi), biomass and leaf area were measured periodically. After 28 months, the CO(2) treatments were changed in all four chambers from ambient to the elevated concentration or vice versa, and A(max) and g(s) were remeasured during a two-week exposure to the new regime. Throughout the 28-month period of exposure, A(max) and apparent quantum yield of leaves in the elevated CO(2) treatment were enhanced, whereas stomatal conductance and stomatal density of leaves were reduced. The relative impacts of atmospheric CO(2) enrichment on assimilation and stomatal conductance were significantly larger in the dry season than in the wet season. Total tree biomass was substantially increased in response to atmospheric CO(2) enrichment throughout the experimental period, but total canopy area did not differ between CO(2) treatments at either the first or the last harvest. During the two-week period following the change in CO(2) concentration, A(max) of plants grown in ambient air but measured in CO(2)-enriched air was significantly larger than that of trees grown and measured in CO(2)-enriched air. There was no difference in A(max) between trees grown and measured in ambient air compared to trees grown in CO(2)-enriched air but measured in ambient air. No evidence of down-regulation of assimilation in response to atmospheric CO(2) enrichment was observed when rates of assimilation were compared at a common intercellular CO(2) concentration. Reduced stomatal conductance in response to atmospheric CO(2) enrichment was attributed to a decline in both stomatal aperture and stomatal density.     

基于主成分分析南京空气污染各成分的关系

根据从南京9个空气环境监测站所得到的空气污染物数据,在空气各成分的相关性指标中,运用主成分分析法,对各个监测样本各个特征性指标进行了分类分析,结果表明：占总方差的79．038％的3个因子来反映空气污染的总体程度,这3个因子归类分别为：①NO2、03、032和SO2,②AQI和03,③PM10和CO。有主成分分析法可以准确地探讨出空气各污染指数准确的内在关系,为当下的环境治理提供一些参考和帮助。     

Effects of Filtered Air and Misting Treatments on Cuticles of Red Spruce Needles on Whiteface Mountain,N.Y.

Two sets of large (8-20 m tall) red spruce (Picea rubens Sarg.) trees growing on Whiteface Mountain, N.Y., were used in branch chamber experiments. In the summer of 1988, the treatments were made on four healthy trees and consisted of: (1) open branches (N), and in chambers that were supplied with either: (2) ambient air (A); (3) charcoal-filtered air (T); or (4) charcoalfiltered air and deionized water misting when the forest was immersed in ambient cloud water (M). Each tree had all of the treatments. The treatments for the second year (summer of 1989) were made on four declining trees and consisted of: (1) open branches (NC) and chambers supplied with either (2) ambient air and mist (AA), (3) synthetic acid mist and ambient air (SA), (4) distilled water mist and ambient air (DA), (5) synthetic acid mist with filtered air (SF), and (6) distilled water mist with filtered air (DF). Foliar properties measurcd included: (1) microreflectivity, a measure of surface wax properties; (2) cuticle thickness; (3) cutinized cell wall thickness; (4) total cuticular layer thickness: (5) the mass of surface wax extracted from needle samples; and (6) contact angles, a measure of surface wetting. In addition, needles were collected and measured from healthy trees at lower and higher elevations. In the first experiment, reflectance from the wax in the stomata1 antechambers in treatment M was statistically significantly greater than all the other treatments. The cuticles of needles in treatment M were also statistically significantly thicker than the cuticles measured in all the other treatments (40% thicker than for the open branches). A plot of cuticular layer against elevation showed that the two filtered chambers (M and T) provided environments for cuticle development that mimic lower elevations. In 1989 the weather was cooler and more moist, and although the trees used in 1989 were declining, the results were similar to those of 1988. However, the additional treatments with synthetic acid mist resulted in reduced cuticle thickness. While the cuticles of the chamber trees growing at 1,170 m were, except for treatment M and T, generally thicker in 1989 than in 1988, they were still considerably thinner than those of spruce trees growing at the lower elevations. These results suggest regional scale air and precipitation quality have detrimental effects on red spruce needles at Whiteface Mountain.     

Dormancy release of Norway spruce under climatic warming: testing ecophysiological models of bud burst with a whole-tree chamber experiment

Ecophysiological models predicting timing of bud burst were tested with data gathered from 40-year-old Norway spruce (Picea abies (L.) Karst.) trees growing in northern Sweden in whole-tree chambers under climatic conditions predicted to prevail in 2100. Norway spruce trees, with heights between 5 and 7 m, were enclosed in individual chambers that provided a factorial combination of ambient (365 micromol mol-1) or elevated (700 micromol mol-1) atmospheric CO2 concentration, [CO2], and ambient or elevated air temperature. Temperature elevation above ambient ranged from +2.8 degrees C in summer to +5.6 degrees C in winter. Compared with control trees, elevated air temperature hastened bud burst by 2 to 3 weeks, whereas elevated [CO2] had no effect on the timing of bud burst. A simple model based on the assumption that bud rest completion takes place on a fixed calendar day predicted timing of bud burst more accurately than two more complicated models in which bud rest completion is caused by accumulated chilling. Together with some recent studies, the results suggest that, in adult trees, some additional environmental cues besides chilling are required for bud rest completion. Although it appears that these additional factors will protect trees under predicted climatic warming conditions, increased risk of frost damage associated with earlier bud burst cannot be ruled out. Inconsistent and partially anomalous results obtained in the model fitting show that, in addition to phenological data gathered under field conditions, more specific data from growth chamber and greenhouse experiments are needed for further development and testing of the models.     

Effects of mist acidity and ambient ozone removal on montane red spruce

Recent forest studies have established that high-elevation (> 900 m) populations of red spruce (Picea rubens Sarg.) in the northeastern USA are declining. Because it has been suggested that changes in air quality are responsible for the decline, we examined the effects of acidic mists and ozone on several biochemical and growth parameters in mature montane red spruce. We used branch-sized environmental chambers to introduce mists of controlled composition and exclude ambient clouds and ozone from individual branches within a tree. Mists consisting of distilled water increased the end-of-season pigment concentration and shoot length of enclosed branches relative to ambient or artificial mists. Needle and twig weights and starch concentrations were not significantly altered by the acidic mist treatments. Removal of ambient ozone had no apparent effect on the variables measured.     

对环境空气质量及应对策略的思考——以贵阳市乌当区为例

以贵阳市乌当区2013年1月1日至1月14日的环境空气质量数据为依据,结合乌当区在贵阳市行政划分中所处的地理位置和气象因素,从内部因素和外部因素两方面简要分析了环境空气质量污染的原因,并提出了相关的意见和建议。