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排序方式: 共有185条查询结果,搜索用时 15 毫秒
1.
沈杰 《中小企业管理与科技》2021,(3)
为了解决航空发动机双通道电子控制器(EEC)两个通道均发生故障时如何评估通道健康度,从而选择主控通道的问题,论文提出了基于逆模型计算发动机推力敏感度的方法,量化不同信号故障对发动机推力的影响程度,依据推力敏感度来评估双通道健康度,协助主控通道选择,最终提高系统的安全性。 相似文献
2.
为解决位置指纹定位在离线阶段构建位置指纹库时耗费的人力和时间成本较大,构建指纹库效率低和利用空间插值法构建的指纹库精度不高的问题,提出了一种融合反距离加权和矩阵填充的位置指纹库构建算法。该算法仅需人工采集定位区域内少量参考点的接收信号强度值用作信标点指纹信息,结合反距离加权算法特性计算出次信标点指纹信息,根据位置指纹库数据矩阵的低秩性,应用奇异值阈值矩阵填充算法构建出位置指纹数据库。仿真实验结果表明,所提算法有效降低了矩阵填充算法构建位置指纹库所需的人工和时间成本,构建出的位置指纹库定位性能优于反距离加权和克里金空间插值法,接近传统人工采集法,显著地提高了位置指纹库的构建效率。 相似文献
3.
In this paper we propose semiclosed-form solutions, subject to an inversion of the Fourier transform, for the price of VIX options and target volatility options under affine GARCH models based on Gaussian and Inverse Gaussian distributions. We illustrate the advantage of the proposed analytic expressions by comparing them with those obtained from benchmark Monte–Carlo simulations. The empirical performance of the two affine GARCH models is tested using different calibration exercises based on historical returns and market quotes on VIX and SPX options. 相似文献
4.
Vincent A. Hildebrand María Noel Pi Alperin Philippe Van Kerm 《Review of Income and Wealth》2017,63(2):288-309
This paper examines the relative well‐being of Portuguese immigrants in Luxembourg by looking at indicators of material deprivation. We document material deprivation differences between immigrants and nationals—the “deprivation gap”—and measure the extent to which income differentials (and other sociodemographic differences) explain this gap using a combination of non‐parametric methods and a versatile graphical device. We find a large and significant deprivation gap against Portuguese immigrants, whatever the indicator considered. The extent to which the gap is merely a reflection of differences in income, however, depends on what deprivation items are taken into consideration. Income differences almost fully account for material deprivation differences when the latter is measured using the items included in the official EU social indicator of material deprivation. Inclusion of housing condition indicators mitigates this relationship and we then find compelling evidence that the deprivation gap is not entirely accounted for by income differentials. 相似文献
5.
东北特殊钢大连基地利用本身设备及技术优势,开发出一系列生产工艺,试制出满足北美压铸协会NADCA207优质钢标准要求的ф140-800mm锻造棒材,经过用户鉴定满足使用要求,特别是Ф600-800mm直径的棒材半径二分之一处的球化组织也完全满足该标准的要求,为技术上的一大突破。 相似文献
6.
7.
叶剑虹 《湖南经济管理干部学院学报》2012,(6):155-156,186
在当前我国产品设计相对薄弱,企业资金投入不足的情形下,较难自主创新,模仿创新成为产品设计跨越式发展的必经之路。模仿创新相较率先创新具有后发优势,反而能设计出占据市场主导地位和最具经济效益的产品。但模仿创新不是恶劣的伪造,重点在于借鉴改造,从而形成自身风格。 相似文献
8.
We propose a stable nonparametric algorithm for the calibration of “top‐down” pricing models for portfolio credit derivatives: given a set of observations of market spreads for collateralized debt obligation (CDO) tranches, we construct a risk‐neutral default intensity process for the portfolio underlying the CDO which matches these observations, by looking for the risk‐neutral loss process “closest” to a prior loss process, verifying the calibration constraints. We formalize the problem in terms of minimization of relative entropy with respect to the prior under calibration constraints and use convex duality methods to solve the problem: the dual problem is shown to be an intensity control problem, characterized in terms of a Hamilton–Jacobi system of differential equations, for which we present an analytical solution. Given a set of observed CDO tranche spreads, our method allows to construct a default intensity process which leads to tranche spreads consistent with the observations. We illustrate our method on ITRAXX index data: our results reveal strong evidence for the dependence of loss transitions rates on the previous number of defaults, and offer quantitative evidence for contagion effects in the (risk‐neutral) loss process. 相似文献
9.
Ruth Kaila 《Quantitative Finance》2013,13(9):1515-1530
If the volatility is stochastic, stock price returns and European option prices depend on the time average of the variance, i.e. the integrated variance, not on the path of the volatility. Applying a Bayesian statistical approach, we compute a forward-looking estimate of this variance, an option-implied integrated variance. Simultaneously, we obtain estimates of the correlation coefficient between stock price and volatility shocks, and of the parameters of the volatility process. Due to the convexity of the Black–Scholes formula with respect to the volatility, pricing and hedging with Black–Scholes-type formulas and the implied volatility often lead to inaccuracies if the volatility is stochastic. Theoretically, this problem can be avoided by using Hull–White-type option pricing and hedging formulas and the integrated variance. We use the implied integrated variance and Hull–White-type formulas to hedge European options and certain volatility derivatives. 相似文献
10.
本文介绍了在一起变电站500kV扩建施工投产过程中,发生了线路反时限零序过流保护动作行为。作者通过研究保护动作时设备的运行状态,仔细分析了反时限零序过流保护的动作条件,发现了回路存在的问题并提出了解决措施。 相似文献