模型

Then the author reviews the content of risk analysis of regional natural disasters and the mathematical models of risk assessment. The risk analysis is classified into three steps, risk recognition , risk estimation, and risk assessment and the mathematical models into three types, extreme risk model, probability risk model and possibility risk model. Nextly, the possibility risk model for analyzing regional disaster risk are reviewed thoroughly.

综述了区域灾害风险分析的内容及区域灾害风险估算的数学模型，指出风险分析可归结为风险辨识、风险估算、风险评价三个环节，风险估算数学模型的演进可概括为极值风险模型、概率风险模型、可能性风险模型三个阶段，着重介绍区域自然灾害风险分析的可能性风险模型。

A new mathematical model is put forward numerically to simulate the wheel ovalization.. In the numerical simulation, the dynamic model of a half railway vehicle coupled with a tangent track is employed. Using the new numerical method investigates vehicle-track coupling system dynamic responses including lateral and vertical displacement of wheelsets and the vehicle, lateral and vertical vibration acceleration of the track at different phase angle of the two side wheels of the same wheelset, which are compared with that of the traditional model. The numerical results show that the discipline and frequency of dynamic responses are accordant, amplitude and phase of lateral dynamic responses are different. It is concluded the traditional track geometric irregularity excitation model does not simulate the effect of periodic wheels ovalization on vehicle-track coupling system dynamic behavior truly, the new model is more accurate and reasonable.

本文研究了车轮二阶周期性非圆化—椭圆化，建立了一个新的模拟车轮椭圆化的数学模型，结合车辆－轨道空间耦合动力学模型，计算了同一轮对左右车轮不同相位和车轮椭圆度下轮对和车体的横、垂向位移，钢轨横、垂向振动加速度，并与传统模型计算结果作了对比，分析表明两种模型的动力响应变化规律和频率一致，但横向动力响应幅值和相位均存在不同程度不可忽略的差异，因此传统的轨道几何不平顺激励模型不能真实模拟车轮的周期性椭圆化对车辆－轨道耦合动态行为的影响，而本文模型更能反映实际椭圆车轮与钢轨接触情形，计算方法准确而合理。

It is proved that the model of Hertz, Capon and Lindel"of areidentical to Vakonomic model while the model of H"older, Pars andChaplygin are identical to Chetaev's model. The fact thatVakonomic model and Chetaev's model exist simultanously can betraced back to the early days of non-holonomic mechanics. These twomodels cause two problems the d- and - permutable problems.

论证了Hertz， Capon和Lindel&of的工作与Vakonomic模型相吻合，而H&older， Pars和Chaplygin的工作与Chetaev模型相吻合，Vakonomic模型和Chetaev模型两类模型并存的局面可以追溯到非完整力学发展的初期。1mm说明了伴随两类模型并存的现象而出现的两个问题 d-交换性问题和-交换性问题。

In this paper, the dynamic phenological models including temperature model, chilling model and others were outlined, among which, temperature model is drawn more concentration than the other models.

本文把动态物候模型分为3大类，温度物候模型、冷激物候模型和其它物候模型，阐述了每个模型的基本原理和假设，重点论述了常见的温度物候模型。

Then, concerning the difficulty of ascertaining hysteresis time of piezometric tube, Genetic Algorithm-Radial Basis Function Neural Network model is developed according as the method that reservior level is rectilinear correlation with piezometric tube level, which not only could be calculated by computer but also is showed logical and feasible.

针对以往监测模型预测精度难以保证的的问题，本文在分析比较了几种土石坝安全监测预报模型的基础上，提出了一种新的安全监测预报模型——遗传回归模型，该模型通过遗传染色体对建模因子进行优选，并在适应度函数中综合考虑模型拟合精度与预测精度平衡。

The traditional DEA model can not beused to deal with such stagewise operation problems. In order to avoid the limitation of the traditional DEA model, a multi-stage DEA model was set up based onthe idea of the DEA model with uncontrollable factor. Simultaneously, considering the shortage of the single DEA model, the multi-stage DEA model was extended to be the multi-objective one.

工程项目某一分期实施阶段的无效率可能导致整体计划的无效，为了克服传统DEA模型评价这类阶段性问题的局限，及时发现并调整工程项目的无效阶段，借鉴具有不可控要素DEA模型的思想建立了多阶段DEA模型，同时考虑到单目标DEA模型的不足，进一步将多阶段DEA模型扩展为多目标模型。

Besides, the effects of light and temperature on stomata have not been modelled in any mechanistic model.

在第一章中，通过综述气孔对环境因子响应的数学模型的文献，发现目前对描述和模拟气孔行为的经验模型和机理模型是脱节的，可供选择的气孔模型还不能满足理论分析和实际应用的需要；经验模型没有机理的支持，不能用于理论分析，没有普适性；机理模型都过于复杂，而且其中的一些参数难以确定，所以它们还只能作定性模拟，不能作定量预测，另外，对于光强和温度的影响还未见有人模拟。

Four thin-layer drying models were investigated for the description of FIR-assisted freeze-drying characteristics. The models were exponential model, Page model, diffusion model, and approximation of the diffusion model. Tests were conducted using a three-level, three-factor (drying temperature, distance between sample and FIR heater, and sample thickness) design, and quadratic polynomial analyses were performed to relate the drying parameters of thin-layer drying model. The performance of these thin-layer drying models was evaluated by comparing the coefficient of correlation (R2), the sum of squares, and the RMSE amongst four models. Drying parameter K of the Page model gave the best results in describing freeze-drying with FIR of Tylose and sweet potato.

运用四种薄层乾燥模型（指数、Page、渗透模型及近似渗透模型）研究远红外线冷冻乾燥之乾燥特性，实验采用三阶层、三因子（远红外线加热器设定温度、远红外线加热器至样品表面之距离及样品之厚度）的实验设计，对於薄层乾燥模型的乾燥参数以二次多项式函数表示之，乾燥参数之二次多项式函数的最适性判断主要是藉由决定系数、模式缺乏适合性及均方根误差等值的比较而加以评估，以Tylose及甘薯样品而言，其中四种薄层乾燥模型的乾燥参数以Page模型之K值的结果为最佳。

the study aims at the actual network status of one work section in daqing oil field,makes a network analysis and planning for the new mixed model of this work section,expends wireless network for the work section on the basis of existing network,and conjoins wire and wireless network together to form an integrated oil field information transfer system.at the same time,using opnet modeler simulation flat roof to structure simulation models (network models,node models and a process model),and analyzing the functions and work mechanism of the major modules for related models,making a simulation for the structured network models,then according to the different parameters,analyzing the individual statistics comparatively such as delay,data dropped and so on,the effects of data packet,data rate and fragmentation threshold to the network performance are gained.after all these,the best structure network scheme for this improved section is determined.

摘 要：此项研究主要针对大庆油田某作业区的实际网络现状，对该作业区进行网络分析和规划，在该作业区现有的有线网络基础上扩充无线网络，实现有线网与无线网的综合，构成一个完整的油田传输信息体系。同时利用opnet modeler仿真平台为该作业区新建混合网络建立仿真模型(网络模型、节点模型和进程模型)，分析相关模型中主要模块的作用和工作机理，对已建立的网络模型进行仿真，在不同的参数设置下，通过对比分析时间延迟、丢包率等统计特性，得出数据包分组、数据率和拆分门限对网络性能的影响，最终决定改进网络的最佳组网方案。

this paper makes the gas remote monitor network as background to do some research on the qos guarantee of the network.qos is a synthesis guide line which can be used to estimate the degree to satisfy with some server,which is a technology to solve the problem of delay and congestion in network.it must integrate multi-qos mechanism to get good qos guarantee in the practical application.three qos models in the ip net application and homologized affective factors are demonstrated.meanwhile,the field of qos protection strategy arrangement in shaanxi coal mine gas network has been picked up as the example.for this situation,the comparison to the different qos models is doing strictly.by combining the tcp congestion control arithmetic with ip congestion control arithmetic,the paper also emphatically describes the corresponded arithmetic model for that.stimulatingly,it is promoted the qos characteristic over-area effectively,which it is based on the original single congestion control.

摘 要：以陕西煤矿瓦斯监测远程联网为背景，研究其联网网络的qos保障策略实现。由于现有的各种qos实现机制无法单独为陕西煤矿瓦斯监测联网网络的qos提供保障，因此在实际应用中必须结合多种机制才能得到较好的qos保障效果。比较了传统ip网络的qos结构体系，通过分析intserv和diffserv两种模型的基本原理、工作方式，并指出其各自的优缺点和网络应用环境，设计了将rsvp协议与diffserv模型相结合来满足瓦斯监测数据传输实时性的要求；针对陕西煤矿瓦斯联网的特性，提出了将tcp拥塞控制算法与ip层拥塞控制算法相结合的算法模型，并且该模型的应用可以在原有单一拥塞控制的基础上有效地提升跨地区网络的qos特性。关键词：服务质量；综合服务模型；区分服务模型；拥塞控制

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失