共查询到20条相似文献，搜索用时 62 毫秒
1.
阐述了私募股权投资的估值问题.首先简要介绍了投资组合问题的发展历史与研究成果.接着较为详细地论述了私募股权投资的估值问题的研究现状,包括有限合伙人的投资组合选择,以及对投资企业的价值评估体系和评估方法的研究,并给出了所要研究的模型,即含有未支撑风险的私募股权投资模型.最后给出所要研究模型在通胀环境、Knight不确定环境下以及跳扩散环境下的拓展框架. 相似文献
2.
降水化学特性的一种分类分析方法 总被引：30，自引：1，他引：29
在分析比较不同地区降水化学特性时,如果列出各种离子的具体数值,既显得繁琐又不容易得出结论。现提出一种简便方法,即先概括出几种最重要的降水化学特性,分别以字母代表,再把这些特性分成几个等级以数字表示,就能很直观方便地比较这些地区的降水化学特性。还利用权威观测资料,以上述方法具体比较了世界主要酸雨地区的降水化学特性。 相似文献
3.
4.
首先,研究了Menger概率度量空间上的非线性算子,证明了非线性压缩与非线性扩张的不动点的存在唯一性;进一步将单个算子的不动点结果推广为一族可交换算子的公共不动点;最后,通过弱化条件,建立了模糊映射新的不动度定理. 相似文献
5.
观测资料的四维质量控制:变分法 总被引：7，自引：1，他引：7
利用四维变分资料同化技术，定义了观测资料的误差均差比，并在理论上初步探讨了利用误差均差比来判断资料中重大误差（ｇｒｏｓｓｅｒｒｏｒ）的合理性。利用简单的Ｌｏｒｅｎｚ模式进行了一些数值试验，以检验质量控制方案。 相似文献
6.
7.
西北太平洋海温与广东省汛期降水的关系 总被引：23，自引：11，他引：23
将西北太平洋分为８个海区，分析了广东省汛期（４－９月）降水与各海区海温的关系，并用因子分析法对９－２月各海区的相互关系进行了分析，发现降维后头４个主因子的方差贡献占总方差的８２．２３％；对主因子的载荷矩阵进行了极大方差旋转，对头４个主因子的物理意义进行了初步的解释。最后建立了汛期各月降水与海温的预报方程，经试报使用，高于近１０年的平均业务预报水平，对广东省的汛期降水短期气候预测有较好的参考价值。 相似文献
8.
In this paper, we delve into the dynamics of a barothropic relaxing medium under pressure perturbations originating from blast wave explosions in the milieu. Analyzing the problem within the viewpoint of the Lyakhov formalism of geodynamic systems, we derive a complex-valued nonlinear evolution equation which models the wave propagation of the pressure perturbations within the barothropic medium. As a result, we find that the previous system can be circularly polarized and hence support traveling rotating pressure excitations which profiles strongly depend upon their angular momenta. In the wake of these results, we address some physical implications of the findings alongside their potential applications. 相似文献
9.
常州用电负荷量气象指数初探 总被引：4，自引：4，他引：4
分析了常州市1998－1999年全市用电量变化特征，建立与其关系密切的最高气温、最低气温、相对湿度、天气状况等气象要素之间的关系，得出其回归计算方程，并分析引起用电量变化的非气象要素，将得到的预报结果进行订正。通过检验、分析，最后确定了用电负荷量指数的划分标准。 相似文献
10.
11.
灌浆期气象条件对小麦灌浆及产量的影响 总被引：2，自引：0，他引：2
利用两种典型年份小麦灌浆期气象资料和产量资料，分析了灌浆期气象条件对灌浆进程及产量的影响，结果表明，土壤水份对灌浆速率和灌浆持续时间均有明显影响，并进而影响产量。 相似文献
12.
13.
在过去数十年中,高光谱图像的研究与应用已经完成了从无到有、从差到优的跨越式发展.在对其研究的众多方面中,高光谱图像分类已经成为了一个最热的研究主题.研究表明空间光谱联合的分类方法可以取得比仅依赖光谱信息的逐像素分类方法更好的分类效果.本文将对众多的空间光谱联合分类方法进行归类和分析.首先介绍高光谱图像中相邻像素间的两类空间依赖性关系,因而可将现有的空谱联合分类方法分为依赖固定邻域和自适应邻域两类;此外,还可以依据是否同时利用两类依赖关系将现有方法进一步分为单依赖和双依赖两类.另外,还可以依据空谱信息融合的不同阶段将现有的分类方法划分为预处理方法、一体化方法及后处理方法三类.最后展示几种具有代表性的空间光谱联合分类方法在真实高光谱数据集上的分类结果. 相似文献
14.
一次局地突发短时冰雹过程雷达回波分析 总被引：1，自引：0，他引：1
本文利用佳木斯雷达站的观测资料,对2010年8月12日清晨桦南县出现的局地突发短时冰雹云的初生、发展、成熟和消亡各阶段的回波演变进行了分析.重点讨论了这次过程中产生冰雹的对流单体回波特征,结合大尺度天气背景及相关雷达产品分析,揭示了此次局地突发短时冰雹天气发生的主要原因,并得出了对突发性冰雹天气的临近预报有参考意义的结... 相似文献
15.
This paper presents a study on potential instability and spiral structure of unstable rain clusters.First,we develop a linearized non-axisymmetrical mathematic model for rain clusters in circular cylindrical coordinates and acquire its analytic solution.Second,we discuss the potential instability of non-axisymmetrical rain clusters.Finally,we conclude that spiral structures can exist in rain clusters.Our analysis indicates that potential instability occurs when humid stratification coefficient is less than zero.Unstable growth rate increases with the increase of the absolute value for humid stratification coefficient.The simpler the vertical structure of perturbation,the thicker the inversion layer;additionally,the smaller the radius of the rain clusters,the larger the unstable growth rate.Simulation results agree well with those from observation and forecast.The spiral structure simulated by our model is similar to a radar echo,suggesting that rain clusters with spiral structures can occur in the atmosphere.In addition,they are generally close to the model solution in this work. 相似文献
16.
法国防雷工作现状及启示 总被引：2，自引：0，他引：2
介绍了法国雷电监测预警系统AMEO 340和防雷业务管理工作,并借鉴其经验,从做好雷电灾害调查与评估和雷电灾害区划,规划建设雷电灾害监测预警平台和预报平台,实现全省雷电业务集约化发展,开展雷电科学技术研究,建立雷电灾害应急处置机制等方面,探讨如何做好防雷业务工作. 相似文献
17.
介绍了法国雷电监测预警系统AMEO 340和防雷业务管理工作,并借鉴其经验,从做好雷电灾害调查与评估和雷电灾害区划,规划建设雷电灾害监测预警平台和预报平台,实现全省雷电业务集约化发展,开展雷电科学技术研究,建立雷电灾害应急处置机制等方面,探讨如何做好防雷业务工作。 相似文献
18.
In this paper, we consider boundary-layer effects on atmospheric fronts. For this purpose we developed a dry, hydrostatic, two-dimensional numerical model with turbulence parameterized with the 1/2 -order eddy viscosity closure of Mellor and Yamada. In the surface layer we use Monin–Obukhov similarity and there is an interactive soil model to obtain lower boundary conditions for the atmospheric model. First, effects of turbulence are studied without thermal forcing at the surface and comparisons are made between inviscid and turbulent conditions. Sensitivity studies with respect to surface roughness are also performed. Subsequently we study effects of surface thermal forcing on fronts. The results show that, during summer, fronts display strong diurnal variation. Vertical velocities increase significantly during the day while gradients in temperature and vorticity across the front strengthen in the evening and at night. In winter the diurnal variation is much less pronounced. We attempt to find physical mechanisms responsible for such frontal behaviour and we compare our results with available observations. 相似文献
19.
The Triptych approach is a sectoral approach for differentiation of quantitative greenhouse gas emission reduction objectives. In this study we investigate the ranges in emission reduction targets that result from differences in valueladen assumptions and uncertainties in input data and parameters. In order to assess the effect of highly valueladen assumptions on resulting objectives we used two approaches. First we performed a sensitivity analysis. Then we elaborated the approach from four ideal-typical value-orientations: the administrator, the businessman, the campaigner and the survivor. For each of these value-orientations we specified corresponding sets of assumptions of highly valueladen parameters. Within each set, we also assessed uncertainties for the remaining parameters and input data. We assessed the strength and we quantified their inexactnesses with probability distribution functions. Next, we carried out Monte Carlo simulations in each of the four value-orientations to quantify error propagation from the inexactnesses in input data and parameters. We found targets for the year 2015 for Annex I countries differed up to around 20%-points over the four value-orientations. For developing countries differences in allowances were found up to the order of four. In addition, results are affected to a large extent by uncertainties in the other input data and parameters. Ranges in the outcome resulting from uncertainties are between 10 and 35%-points for Annex I countries, depending on the value-orientation chosen and between 20 and 120%-points for non-Annex I countries. However, the ranking of countries within the calculated differentiation remains roughly the same, an exception being the ranking that resulted from the businessman’s perspective. Other consistent combinations of valueladen assumptions may result in objectives that are outside the range that we based on the four value-orientations. We concluded that care should be taken when assessing valueloading in calculations schemes for emissions objectives based on a limited number of value-orientations only. Our analysis clearly underlines the relevance of making explicit policy variables in schemes for the differentiation of commitments. It is necessary to reach consensus on these variables if such schemes are to support negotiations on greenhouse gas emissions allowances. 相似文献
20.
Geoffrey Heal 《Climatic change》2009,96(3):275-297
What have we learned from the outpouring of literature as a result of the Stern Review of the Economics of Climate Change? A lot. We have explored the model space and the parameter space much more thoroughly. The Stern Review has catalyzed a fundamental rethinking of the economic case for action on climate change. We are in a position to give some conditions that are sufficient to provide a case for strong action on climate change, but we need more work before we have a fully satisfactory account of the relevant economics. In particular, we need to understand better how climate change affects natural capital—the natural environment and the ecosystems comprising it—and how this in turn affects human welfare. 相似文献