风浪谱模型在苏北辐射沙洲海域的应用研究

通过分析和比较几种常用的近岸波浪数值模式,选用了基于波能平衡方程和波作用守恒方程的近岸风浪谱模型,建立了苏北辐射沙洲海域的波浪传播计算数值模型,并对苏北辐射沙洲海域的波浪的传播过程进行数值模拟。模型能充分考虑外海波浪在传播的过程中受到风的影响,能够模拟波浪传播过程中的浅水变形、折射、破碎、底摩阻耗散以及由于风能输入、白浪耗散和波波相互作用等引起的能量的输入和转移等多重物理过程。将建立的模型的计算结果与经验公式计算结果进行比较分析,说明波浪在远距离的传播过程中,沿程的底摩阻耗散、风能输入以及波波非线性相互作用等物理现象的影响是不可忽略的,在苏北辐射沙洲海域采用近岸风浪谱数值模型对波浪的传播变形计算较为合适,模型可用于苏北辐射沙洲海域的促淤圈围工程的设计波浪要素的计算。     

Extreme Measures of Agricultural Financial Risk

The agricultural marketing environment is inherently risky. Having accurate measures of risk helps farmers, policy‐makers and financial institutions make better informed decisions about how to deal with this risk. This article examines three tail quantile‐based risk measures applied to the estimation of extreme agricultural financial risk for corn and soybean production in the US: Value at Risk, Expected Shortfall and Spectral Risk Measures. We use Extreme Value Theory to model the tail returns and present results for these three different risk measures using agricultural futures market returns data. We compare estimated risk measures in terms of size and precision, and find that they are all considerably higher than Gaussian estimates. The estimated risk measures are also quite imprecise, and become more so as the risks involved become more extreme.     

宽带卫星通信中的ACM技术

采用自适应编码调制技术(ACM)的卫星数字视频广播新标准(DVB-S2)应用到宽带卫 星通信网中,将极大提升系统吞吐量,提供更丰富的交互式业务。从实际应用的角度,分析 了ACM的控制机制并提出其编码调制方案的简化方法。仿真结果表明,在几乎不影响系统性 能的前提下,该方案可以大幅降低ACM机制的复杂度。     

激光散射法测定那他霉素粒度研究

为了减少那他霉素原料药各批次之间的粒度差异,提高其制剂产品质量和疗效稳定性,建立了一种激光散射法测定那他霉素粒度的方法。采用Mastersizer 2000激光粒度仪干法测定那他霉素粒度,分别对分散气压、振动进样速度及测量时间等关键测定参数进行了优选,并对本方法的重复性、中间精密度和耐用性进行了验证。结果表明：在分散气压为0.30 MPa、振动进样速度为45%、背景和测量扫描时间为10 s、样品折射率为1.50、颗粒吸收率为0.1、遮光度范围为0.5%~5%等条件下,所测样品的RSD均小于2.5%。方法学各项验证指标相对标准偏差均符合要求。所建立的测定那他霉素粒度的激光散射法精密度较高、重复性好,能够有效控制原料药的批间差异,可为生产出安全、有效、均一、稳定的制剂产品提供保障和参考。[HJ4mm]     

分析微生物检测技术在食品检验中的应用

本文针对微生物检测技术检测指标、技术特征、必要性等内容展开分析,结合免疫学技术、光谱技术、代谢学技术、分子生物学技术、质谱检测技术、传感器技术在食品检验中的应用要点,目的在于提升食品检验结果可靠性,为技术体系的不断完善奠定基础。     

Predicting domain-specific risk-taking attitudes of mainland China university students: a hyper core self-evaluation approach

This study applied the framework of hyper core self-evaluation to examine the risk-taking attitudes, in the ethical, financial, health/safety, recreational, and social domains, of 437 university students from Harbin, China. Under the hyper core self-evaluation approach, overconfidence and hubristic pride were found to be significant predictors of risk-taking attitudes in the ethical, financial, and health/safety domains. The control variable of sensation seeking found in the Impulsive Behavior Scale was also significant in predicting risk-taking attitudes in certain domains. Different regression analysis models were run to generate these results. Limited studies have focused on Chinese university students’ risk taking attitudes in different domains, and most studies have merely applied sensation seeking and impulsivity in understanding risk-taking. However, this empirical study contributes to finding out whether a particular group of Chinese students had high levels of overconfidence and hubristic pride (as many young people do) and whether these common characteristics could contribute to the understanding of risk-taking attitudes in the five domains.     

Decision making with Expected Shortfall and spectral risk measures: The problem of comparative risk aversion

We analyze spectral risk measures with respect to comparative risk aversion following Arrow (1965) and Pratt (1964) for deterministic wealth, and Ross (1981) for stochastic wealth. We argue that the Arrow–Pratt-concept per se well matches with economic intuition in standard financial decision problems, such as willingness to pay for insurance and simple portfolio problems. Different from the literature, we find that the widely-applied spectral Arrow–Pratt-measure is not a consistent measure of Arrow–Pratt-risk aversion. Instead, the difference between the antiderivatives of the corresponding risk spectra is valid. Within the framework of Ross, we show that the popular subclasses of Expected Shortfall, and exponential and power spectral risk measures cannot be completely ordered with respect to Ross-risk aversion. Thus, for all these subclasses, the concept of Ross-risk aversion is not generally compatible with Arrow–Pratt-risk aversion, but induces counter-intuitive comparative statics of its own. Compatibility can be achieved if asset returns are jointly normally distributed. The general lesson is that these restrictions have to be considered before spectral risk measures can be applied for the purpose of optimal decision making and regulatory issues.     

“超阅读”对现代教学的负面影响

在界定超阅读的涵义 ,肯定超阅读对教育和教学的正面影响的前提下 ,指出了它的负面影响 :对学习过程的有效监督不足 ;难以有效地避免垃圾信息对学生的影响 ;忽视了收敛性思维和系统知识的作用 ;弱化了以协作为核心的集体主义教育等。认为避免这些负面影响的措施主要有 :加快与网络相关的立法进程 ,加大对网络控制技术研究的投入 ,利用传统媒体提高受众对网上垃圾信息的免疫力 ;在进行导航设计时 ,注意学生的年龄特征 ,注意遵循情感、意志方面的心理规律 ;重视对网下学习和生活的指导 ,开辟发挥教师主导作用的新渠道 ,弥补网上超阅读监控权的不足。     

Non-exponential Bounds for Ruin Probability with Interest Effect Included

In this paper, we consider a discrete time risk model. First we discuss the classical model, both exponential and non-exponential upper bounds for ruin probabilities are obtained by using martingale inequalities. Then similar results are obtained for the model with investment income.     

A folding methodology for multivariate extremes: estimation of the spectral probability measure and actuarial applications

In this paper, the folding methodology developed in the context of univariate Extreme Value Theory (EVT) by You et al. is extended to a multivariate framework. Under the usual EVT assumption of regularly varying tails, our multivariate folding allows for the estimation of the spectral probability measure. A new weakly consistent estimator based on the classical empirical estimator is proposed. Its behaviour is illustrated through simulations and an actuarial application relative to reinsurance pricing in the case of an insurance data-set.