膜下粮面施药与通风口施药熏蒸效果对比试验

通过对采用膜下粮面施药与通风口施药两种方式的试验对比，两种方式均能达到较好的杀虫效果。粮面施药需要进入仓房操作，而通风口施药是在露天环境下作业，简便、安全。熏蒸时可根据情况选择不同的施药方式。     

Machine learning for quantitative finance: fast derivative pricing,hedging and fitting

In this paper, we show how we can deploy machine learning techniques in the context of traditional quant problems. We illustrate that for many classical problems, we can arrive at speed-ups of several orders of magnitude by deploying machine learning techniques based on Gaussian process regression. The price we have to pay for this extra speed is some loss of accuracy. However, we show that this reduced accuracy is often well within reasonable limits and hence very acceptable from a practical point of view. The concrete examples concern fitting and estimation. In the fitting context, we fit sophisticated Greek profiles and summarize implied volatility surfaces. In the estimation context, we reduce computation times for the calculation of vanilla option values under advanced models, the pricing of American options and the pricing of exotic options under models beyond the Black–Scholes setting.     

Perceptual Density of Guava Juice: The Effect of Image Location and Surface Texture

Guava is known for its rough (astringent) appearance and texture; feature attached to its nutritional benefits but rejected from consumers’ point of view. This study deals with the rough property of guava juice through packaging expecting to influence its perceived density. Two studies were designed by manipulating (a) the location of the image on the bottle and (b) the surface texture of the bottle, controlling for transparency. Results confirm that it is possible to shift the perception of density in guava juice (a) locating the image of the fruit on the top (not the bottom) of the bottle and (b) using a smooth surface texture (not a rough) on an opaque bottle. Concerning practical implications, agribusinesses should enforce the use of sensory marketing strategies to sell the best of fruits and vegetables.     

安徽城乡医疗救助“夹心层”权益保障问题研究

如发生不符合安徽省城乡医疗救助病种限制的大病或慢性病,需要巨额医疗费用时,而产生的城乡医疗救助＂夹心层＂是安徽省现行城乡医疗救助政策的一个制度漏洞。对＂夹心层＂实施医疗救助,是填补现行城乡医疗救助制度漏洞的有效方案。     

Smooth and bid-offer compliant volatility surfaces under general dividend streams

Abstract

Given bid-offer quotes for a set of listed vanilla options, a fundamental need of option market makers is to interpolate and extrapolate the available quotes to a full arbitrage-free surface. We propose a methodology which directly controls the trade-off between smoothness and bid-offer compliance of the resulting volatility surface. Unlike previous literature, the method applies simultaneously to all listed maturities and aims to smooth the implied risk-neutral densities. Additionally, we consider asset dynamics which allow for general dividend streams—continuous, discrete yield and discrete cash—a modelling aspect of key importance in option markets.     

面波法波速测试在岩土工程勘察中的应用

文章简述了面波法波速测试方法的工作原理、现场施测技术以及数据处理和资料分析过程,运用工程实例说明了面波法波速测试技术在岩土工程勘察设计中的应用和效果。     

浅谈项目施工成本控制

阐述了施工成本控制内容,目前存在的问题,并提出了方法措施及需树立的观点。     

水泥混凝土路面的抗裂措施综述

从水泥混凝土路面开裂破坏过程及其影响因素进行了研究分析,并根据原因分析从各方面提出抗裂防治措施。     

Can we forecast the implied volatility surface dynamics of equity options? Predictability and economic value tests

We examine whether the dynamics of the implied volatility surface of individual equity options contains exploitable predictability patterns. Predictability in implied volatilities is expected due to the learning behavior of agents in option markets. In particular, we explore the possibility that the dynamics of the implied volatility surface of individual stocks may be associated with movements in the volatility surface of S&P 500 index options. We present evidence of strong predictable features in the cross-section of equity options and of dynamic linkages between the volatility surfaces of equity and S&P 500 index options. Moreover, time-variation in stock option volatility surfaces is best predicted by incorporating information from the dynamics in the surface of S&P 500 options. We analyze the economic value of such dynamic patterns using strategies that trade straddle and delta-hedged portfolios, and find that before transaction costs such strategies produce abnormal risk-adjusted returns.     

无铅化PCB工艺特点和表面材料研究

无铅化的PCB表层有多种形式,包括浸锡、浸银、浸金和有机焊接保护等,而PCB工艺技术包括电镀、化学镀和浸镀等多种方式。不同的工艺具有不同的优缺点,针对于不同的无铅化表层材料,其工艺与材料的兼容性也不同。本文主要从可生产性、制造型和匹配性等方面进行PCB表层技术进行分析,通过对可靠性的评估进行材料与工艺的匹配。