624 research outputs found

    Option Pricing Model Based on Newton-Raphson Iteration and RBF Neural Network Using Implied Volatility

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    As option is a kind of significant financial derivatives, option pricing will affect both the risk and profit of the investment. This paper proposed an option pricing model based on RBF neural network combined with the Newton-Raphson iteration method which is used to obtain the implied volatility.First, considering implied volatility includes investors’ expectation about the changes of future price options. Newton-Raphson iteration method is used to obtain the implied volatility by rolling estimation which is also added into the RBF neural network model. Then, RBF neural network is trained based on Black-Scholes model. Self-organizing learning and the least square method are used to optimize the parameters of RBF neural network.At last, empirical study and analysis with 10 50ETF stock options chosen from Shanghai Stock Exchange market have been performed, the result shows that the accuracy of the proposed model is better than the traditional BP neural network and B-S model and the effect of option pricing using by implied volatility is also better than others

    Housing market of a medium-size city in China : A case of Xiamen

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    Master'sMASTER OF SCIENCE (ESTATE MANAGEMENT

    MiR-155 protects against sepsis-induced cardiomyocyte apoptosis via activation of NO/cGMP signaling pathway by eNOS

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    Purpose: To examine the impact of miR-155 on sepsis-induced myocardial apoptosis and heart failure, and to explore its molecular mechanism. Methods: Mice were divided into four groups and septic myocardial dysfunction was induced by intraperitoneal injection of lipopolysaccharide (LPS, 5 mg/kg). The LPS stimulation expression of miR-155 levels was determined by real time-polymerase chain reaction (RT-PCR). In vivo, echocardiography and TUNEL staining were used to investigate the effects of miR-155 in inhibiting cardiac function and myocardial apoptosis. Changes in the expression of eNOS when miR-155 was overexpressed or inhibited were determined by RT-PCR, while double luciferase gene assay assessed the relationship between eNOS and miR-155, eNOS, expression of iNOS, SGC alpha 1, and PKG protein. Results: MiR-155 was significantly increased after LPS stimulation (p < 0.01). In vitro, the inhibition of miR-155 by antagomiR significantly down-regulated the apoptosis of cardiomyocytes (p < 0.05), while overexpression of miR-155 by agomiR significantly up-regulated the apoptosis of cardiomyocytes (p < 0.05). In vivo, ejection fraction, fractional shortening and heart weight were significantly increased (p < 0.05), while apoptosis was significantly decreased (p < 0.05). MiR-155 negatively regulated the expression of eNOS (p < 0.01), and targeted the expression of eNOS mRNA (p < 0.001). In addition, the expression of eNOS, sGCα1 and PKA were significantly up-regulated (p < 0.05), while the expression of iNOS was significantly down-regulated (p < 0.05) after the inhibition of miR-155 in LPS mouse model. Conclusion: MiR-155 regulates sepsis-induced cardiomyocyte apoptosis and heart failure through eNOS /NO/cGMP signaling pathway. Thus, these findings can potentially facilitate the development of an effective strategy for management of heart failure

    Solar Radiation Parameters for Assessing Temperature Distributions on Bridge Cross-Sections

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    Solar radiation is one of the most important factors influencing the temperature distribution on bridge girder cross-sections. The bridge temperature distribution can be estimated using estimation models that incorporate solar radiation data; however, such data could be cost- or time-prohibitive to obtain. A review of literature was carried out on estimation models for solar radiation parameters, including the global solar radiation, beam solar radiation and diffuse solar radiation. Solar radiation data from eight cities in Fujian Province in southeastern China were obtained on site. Solar radiation models applicable to Fujian, China were proposed and verified using the measured data. The linear Ångström–Page model (based on sunshine duration) can be used to estimate the daily global solar radiation. The Collares-Pereira and Rabl model and the Hottel model can be used to estimate the hourly global solar radiation and the beam solar radiation, respectively. Three bridges were chosen as case study, for which the temperature distribution on girder cross-sections were monitored on site. Finite element models (FEM) of cross-sections of bridge girders were implemented using the Midas program. The temperature–time curves obtained from FEM showed very close agreement with the measured values for summertime. Ignoring the solar radiation effect would result in lower and delayed temperature peaks. However, the influence of solar radiation on the temperature distribution in winter is negligible

    CeNiAsO: an antiferromagnetic dense Kondo lattice

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    A cerium containing pnictide, CeNiAsO, crystallized in the ZrCuSiAs type structure, has been investigated by measuring transport and magnetic properties, as well as specific heat. We found that CeNiAsO is an antiferromagnetic dense Kondo lattice metallic compound with Kondo scale TKT_K \sim 15 K and shows an enhanced Sommerfeld coefficient of γ0\gamma_0 \sim 203 mJ/mol\cdotK2^{2}. While no superconductivity can been observed down to 30 mK, Ce ions exhibit two successive antiferromagnetic (AFM) transitions. We propose that the magnetic moment of Ce ion could align in the G type AFM order below the first transition at TN1T_{N1}=9.3 K, and it might be modified into the C type AFM order below a lower transition at TN2T_{N2}=7.3 K. Our results indicate that the 3d4fd-4f interlayer Kondo interactions play an important role in Ni-based Ce-containing pnictide.Comment: 13 pages, 5 figures, to appear in J. Phys.: Condens. Matte
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