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1.
为全面评估雾霾天气对经济社会生态的安全状况,基于自然灾害系统理论构造了雾霾危害综合风险评估体系并结合层次分析法和熵权法计算了各子因素权重,采用物元可拓模型计算长三角三省市雾霾危害综合风险的关联系数、判定等级.计算结果表明:上海市综合风险等级判定为严重,江苏省综合风险等级处于轻度,浙江省综合风险等级处于微度,同时使用综合指数法的计算结果验证了结果可信.最后根据三省市各项风险因素的权重大小、风险等级和改变难度综合评价各项风险因素,确定了长三角各省市降低雾霾危害风险水平的关键因素.  相似文献   

2.
针对我国农产品滞销问题频发的现象,在历年农产品实际生产数据的基础上,通过建立SC-RC矩阵,分析判别影响农产品滞销的主要因素,根据得到的因素利用模糊综合评价法对主要因素进行权重分析,并应用层次分析法对风险等级指标进行了量化,最后建立农产品滞销风险等级的评判模型.并以山东省农产品滞销为例对评判模型进行了验证,证明这种评判方法具有可行性和科学性,同时对减少农产品滞销风险提出相关的政策建议.  相似文献   

3.
矿井火灾事故的发生常常导致大量的人员伤亡、设备损失、矿井停产、资源破坏,甚至会引起瓦斯、煤尘和硫化矿尘发生爆炸,给企业和国家造成重大的经济损失.在国内外相关研究成果的基础上,对矿井火灾安全评价体系和评价方法进行了系统研究,首先将熵权法和可变模糊评价方法进行耦合,建立了矿井火灾安全评价的熵权可变模糊评价模型;其次对矿井火灾安全影响因素进行分析,参考其他学者的研究成果和矿井的具体实际情况,建立了矿井火灾安全评价指标体系,同时给出了5个安全评价等级和每个等级各指标的界限值;最后利用所建立的熵权可变模糊评价模型对山东省6个矿井火灾安全性进行评价,得出矿井1、矿井3和矿井5处于较安全状态,矿井2、矿井4和矿井6处于临界安全状态,评价结果可为矿井的安全管理提供一定理论参考.  相似文献   

4.
为克服旅游上市公司财务风险评价方法的不足,提出可变模糊改进方法.首先,基于集对模糊联系度,构造相对隶属度矩阵,进而建立可变模糊综合评价模型;然后,结合评价等级特征值,运用二元语义方法确定评价等级和阈值;最后,将方法应用于旅游上市公司财务风险评价问题.结果表明:旅游上市公司财务风险等级为Ⅱ级,即风险较低,且通过计算可发现收现能力和成长能力是影响其风险等级的主要因素,是旅游上市公司财务风险管理的重点.  相似文献   

5.
王涛 《大学数学》2006,22(2):5-10
模糊综合评判是一种应用广泛的模糊数学方法,是在综合考虑和整体平衡中顾及各种因素全面进行评判的科学方法,可广泛应用在各类人员、工作、产品等等客体的综合评判工作中.本文主要采用模糊数学理论对我院排课系统进行综合评价,经确定评判因素集、权重、等级评语向量和评价矩阵等,从而得到了三级模糊综合评判模型.结果表明该模型用于排课系统评估,客观公正,可信度高.  相似文献   

6.
网络舆情是社会舆情在网络空间中的映射,体现了社会稳定和谐程度.网络舆情态势分析对于有效预测和把握舆情导向具有重大的意义.文章主要研究构建基于TOPSIS的网络舆情态势等级模糊多指标综合评价模型.首先,根据网络舆情态势演化形成原因和发展规律,建立了网络舆情态势等级评价三级指标体系,提出了基于有序比值方法的网络舆情态势等级评价指标权重的确定方法.然后,构建了基于TOPSIS的网络舆情态势等级模糊多指标综合评价模型.最后,通过魏则西事件验证了该模型的有效性和适用性,并与线性加权综合评价模型进行对比分析,说明了文章模型的优越性.研究结果对政府和相关舆情监管人员及时有效的管理和引导网络舆情具有重要的指导意义与参考价值.  相似文献   

7.
城市规模与道路网络是一对互为动力的城市发展因子,两者的协调配合促进城市交通体系的健康发展.利用可拓学理论将两者协调发展的评价指标体系、评价等级范围以及指标特征值结合成物元,建立城市规模与路网系统协调程度的物元评价模型,并考虑主客观条件,采用熵值权重与主观权重的融合权重来确定评价等级,增加评价结果的可靠性.最后通过成都市中心城的统计数据,对城市规模和路网系统协调程度进行评价,验证方法的实用性和可操作性,结果表明目前成都市中心城的路网水平在一定程度上能够较好适应城市规模的需求,评价等级为优,但仍有较大提升空间,管理部门在城市发展的过程中应继续关注路网系统的完善.  相似文献   

8.
基于灰色聚类-SPA的建筑施工项目安全风险评价   总被引:2,自引:0,他引:2  
针对建筑施工阶段的安全风险,建立了基于灰色聚类-集对分析(SPA)的建筑施工项目安全风险的综合评价模型.在应用SPA确定安全风险评价因素权重的基础上,采用灰色聚类方法对建筑施工项目进行聚类分析,评价建筑施工项目安全风险所处的等级,最后依据SPA中集对势等级次序表分析建筑施工项目安全风险发展态势.实例分析证明了该模型的适用性和合理性,对比分析表明其评价结果的可靠性,为施工企业的安全风险决策提供借鉴.  相似文献   

9.
针对大型酒店消防管理的复杂性,综合考虑高层建筑空间火灾发生及消防救援的特点,建立全面多系统的消防安全综合评价指标体系.采用Delphi法将定性指标量化,引入物元可拓理论分析法构建综合可拓评价模型,得到各准则层及系统整体的风险等级和偏离所属等级的趋向程度.以长春市某大型酒店为例,验证了该体系的科学性和可行性.  相似文献   

10.
为完善山体隧道结构安全评价方法,提高运营期保障可靠度.首先在分析隧道结构固有属性和动态影响因素的基础上,构建了能够全面反映山体隧道结构安全的评价指标体系,并对不同等级下指标值进行无量纲化处理.其次将区间模糊数与可拓理论相结合提出山体隧道结构安全评价模型,关联度由不确定型可拓初等关联函数确定,指标权重由区间模糊熵权法求解,并采用集结算子进行综合评价.最后,以霞浦洋坪隧道为例,按照模型步骤对其结构安全进行了系统评价,同时与其它已有方法进行了对比分析.研究成果不仅丰富山体隧道安全评价模型,也为交通部门决策提供了参考.  相似文献   

11.
Control in anaerobic wastewater treatment plants is difficult to achieve but necessary due to a high sensitivity to disturbances and process complexity. With the help of different mathematical tools, control strategies can be developed. Particularly, a well-defined mathematical model can be highly effective for design, assessment and optimization of treatment plants. However, applications directly in the control system of a treatment plant are hard to achieve due to model complexity and usually require specialized software and the engagement of experts in the subject. The objective of the present study was the development of less empirical methods for assessment and control of a decentralized anaerobic plant for the treatment of domestic wastewater. A lab-scale plant, which consisted of a two-stage anaerobic digestion process followed by an anaerobic ammonium oxidation (ANAMMOX) reactor for nitrogen removal, was used as object of study. Ordinary differential equation models were implemented to simulate the processes that took place in the treatment plant. With the help of the implemented models, control tools were developed. These tools include a standalone application for monitoring of the two-stage anaerobic digestion process and an ammonium estimator for the ANAMMOX reactor by means of artificial neural networks (ANNs). The procedures followed aimed to reduce the amount of experimental work required so they can be easily transferred from laboratory to full-scale conditions. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

12.
系统动力学在城市污水再生回用系统中的应用   总被引:5,自引:0,他引:5  
用系统动力学方法研究了城市污水回用系统.首先分析了影响城市污水回用系统的诸多因素以及它们之间的相互关系,探讨了污水再生回用系统行为和结构的特点,确定了系统中因素之间的定量关系,建立了城市污水回用系统动力学(SD)模型,并介绍了模型的检验方法.同时给出了SD模型的具体应用实例,对西北地区的某一城市的污水回用进行了预测和分析,提出了符合该城市发展的污水回用方案.  相似文献   

13.
This study introduces the concept of computer modelling and simulation of complex bioprocesses and systems using an approach that combines the reference net formalism with machine learning and optimisation techniques. Reference nets are an extension of high level Petri Nets, which can be used as a central visualisation and modelling tool. The net-in-net paradigm used by reference nets makes it possible to model complex processes, such as those found in the food and beverage industry. A plugin/interface system based on the java programming language allows implementation of advanced mathematical modelling techniques at specific points in entire system simulations. Separate optimisation tools can also run and modify existing reference net models for fast solutions to efficiency problems. We present an example system that simulates a specific section of a beer brewery using the reference net formalism, which is optimised using a genetic algorithm. We show in detail how the different software packages can be combined for a simulation based optimisation approach. The optimisation technique specifically addresses the wastewater pollution load in regard to its chemical oxygen demand. A beer brewery was chosen as an example for this study due to the constantly increasing requirements to lower energy and water consumption in this industry. One possibility to lower the energy and water demands is to effectively treat wastewater produced by the brewery, which can introduce cost savings by providing recycled water and biogas. Most approaches to wastewater treatment are end-of-pipe solutions that do not consider the brewery as a whole. A brewery contains many processes that can be running concurrently and interacting with one another (e.g. brewing, clean-in-place and bottling) with each process producing varying amounts of wastewater with different pollution loads. Optimisation of the scheduling of the different processes with respect to the wastewater production will allow for more effective wastewater treatment, and therefore cost and energy savings. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

14.

Several large-scale wastewater treatment plants have been modelled successfully using an extensive modelling library in the General Purpose Simulator, GPS-X. The mathematical models included all important processes on the selected wastewater treatment plants, i.e. primary sedimentation, activated sludge biokinetics and final clarification.The models have been used in different areas, such as: a)analysis of operational scenarios; b) determenation of sustained and peak capacity of plants(rated plant capacity) and c) investigation of plant expansion scenarios. Out of more than twenty documented cases four, involving simulation studies on large-scale wastewater plants are discussed.  相似文献   

15.
本文利用截面分析方法,从多个角度讨论影响股票市盈率水平的因素,并利用上海证券交易所股票数据进行验证。首先,利用上海证券交易所的股票历史数据计算按不同板块 (如行业,每股收益大小等)划分股票类别时,各板块市盈率水平的具体数值,并讨论各不同板块市盈率的分布特征。其次,讨论了市盈率与其直接影响变量(股票价格和每股收益 )之间的相互关系,用数学模型论述两者在影响市盈率变化时所存在的差异。最后,通过对影响市盈率水平的各种因素进行详细的统计特征分析,筛选影响强烈的因素,并建立了描述市盈率与各影响因素之间相关性的多因素模型。  相似文献   

16.
The aim of this work is to develop an integrated control of anaerobic digesters in wastewater treatment plants, to ensure optimal depollution performances. To achieve this goal, we have to summarise our knowledge in a mathematical model, which is an essential tool for control design. Various control strategies can be chosen, but their performances are very different (stabilisation, biogaz production,...). Each of them is evaluated through 3 criteria. Then we present an original linear model for process stability which take into account the input pollution (flow rate, concentration). We show with simulations how this model help us to select the appropriate control strategy and the improvement of depollution efficiency.  相似文献   

17.
A new mathematical model for wound healing is introduced and applied to three sets of experimental data. The model is easy to implement but can accommodate a wide range of factors affecting the wound healing process. The data sets represent the areas of trace elements, diabetic wounds, growth factors, and nutrition within the field of wound healing. The model produces an explicit function accurately representing the time course of healing wounds from a given data set. Such a function is used to study variations in the healing velocity among different types of wounds and at different stages in the healing process. A new multivariable model of wound healing capable of analyzing the effects of several variables on accelerating the wound healing process is also introduced. Such a model can help to formulate appropriate strategies to treat wounds. It also would enable us to evaluate the efficacy of different treatment modalities during the inflammatory, proliferative, and tissue remodeling phases.  相似文献   

18.
New solutions to the navigation problem related to low-cost integrated navigation systems (INS) are often published. Since these new solutions are generally compared with ad hoc mathematical models that are not fully exposed, one cannot be sure of the relative improvements. In this work, complete mathematical model for a low-cost INS is suggested to be used as a benchmarking. As far as the authors’ knowledge, a benchmarking for low-cost INS has not been previously reported. Shown INS comprises a strapdown inertial navigation system, loosely coupled to a GPS receiver. The INS mathematical model is based upon classical navigation equations and classical sensor models, both from recognized authors. The algorithm that details the INS operation is also presented. The benchmarking is provided as an open-source toolbox for MATLAB. Additionally, this work can be taken as a starting point for new practitioners in the INS field. To validate the INS mathematical model, real-world data sets from three different Micro Electro-Mechanical Systems (MEMS) inertial measurement units (IMU) and a GPS receiver are processed. It is observed that obtained RMS errors from the three INS are coherent with the quality of corresponding MEMS IMU. This confirms that the proposed benchmarking is a suitable tool to evaluate objectively new solutions to low-cost INS.  相似文献   

19.
以害虫综合防治数学建型为启迪,对生物数学研究的一些相关问题开展了一系列的研究.从实际问题出发,我们分别建立了"常微分方程模型"以及对应的"周期脉冲控制模型";随着害虫综合防治常态化管理和环境污染常态化防治的兴起,我们建立了"状态脉冲反馈控制系统"模型,简称"半连续动力系统"模型,提出了"半连续动力系统"相关的概念,创建了其基本理论,并且作了系统性的研究,例如:半连续动力系统的周期解以及周期解的稳定性、同宿轨和同宿分支、异宿轨和异宿分支以及"双边控制系统"等概念及其判定定理的研究;进一步将"半连续动力系统"相应的理论和方法应用于生物数学其他方面的一些相关问题的研究.本文以数学模型为载体,归纳总结了近十多年来对生物数学的研究历程,指出了当前研究中尚待解决的问题.  相似文献   

20.
In this paper, a decision-making framework (DMF) based on stochastic dynamic programming (SDP) is presented for a wastewater treatment system, consisting of a liquid treatment line with eleven levels and a solid treatment line with six levels (Chen and Beck, 1997). A continuous-state SDP solution approach based on the OA/MARS method (Chen, Ruppert, and Shoemaker, 1999) is employed, which provides an efficient method for representing a wide range of possible influent conditions. The DMF is used to evaluate current and emerging technologies for the multi-level liquid and solid lines of the wastewater treatment system. At each level, one technology unit is selected out of a set of options which includes the empty unit. The DMF provides a comparison on possible technologies for screening which types of technologies may best be further developed in order for an urban wastewater infrastructure to be judged progressively more sustainable. The results indicate that one or a pair of technologies are dominant in each level. The cheap, lower-technology unit processes receive a mixed review. Some of them are selected as the most promising technology units while the others are not considered as good candidates.  相似文献   

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