上市房地产企业零杠杆现象影响因素研究

在利用滑动相关系数描述两市波动溢出强度基础上，实证选择了马尔科夫体制转换ARMA(1,1)刻画我国股市和债市的体制转换特征；接着利用LR检验等验证了MS-ARMA(1,1)整体及各类参数结构变化的显著性；然后利用概率外推法预测了短期内两市的波动溢出强度变动趋势.结果表明，两市体制转换非对称，正相关状态持续期更长，体制转换中存在交替的逃离效应和传染效应特征.     

机构持股对房地产股票收益波动的影响研究——基于面板数据的门限分位回归模型

针对在不同的股市行情中机构持股与房地产公司股票收益波动之间的相关性问题,建立面板数据的门限分位回归模型进行检验。证实在不同的市场行情中,对于股票收益波动处于不同水平的房地产公司,机构持股的影响程度存在差异。当股市大盘出现极端情形,机构投资者加剧股市波动。大盘大跌,机构持股的促进作用随着股票收益波动的分位点的增大而增强。在盘整市,机构持股比例没有对股票收益波动产生显著影响,但其变动抑制股票收益波动。     

沪深股票市场之间波动性影响关系研究

以对沪深两市波动性指标的解构分析为基础,给出了基于GRACH模型、Granger模型的综合运用,同时引入协整检验和误差纠正机制的均衡分析方法,对沪深两市的波动相关性进行实证分析和模型检验,系统性揭示了沪深两市波动性的关键特征和沪深两市波动互相影响的因果规律,为基于沪深两市金融资产的定价和风险管理奠定了基础.     

基于藤结构 Copula 模型的中国股市风格资产相依结构研究

首先采用 AR(1)－GJR(1,1)－SkT(v,λ) 模型来刻画中国股市风格资产（大盘成长、大盘价值、中盘成长、中盘价值、小盘成长、小盘价值）的边缘分布,接着结合各边缘分布的残差,引入C-Vine Copula和D-Vine Copula模型来描述这六种风格资产之间的相依结构,然后对基于C-Vine Copula和D-Vine Copula模型的拟合效果进行综合比较.研究结果表明：中国股市各风格资产之间的相依性存在结构性差异,最适合用D-Vine Copula模型来刻画各风格资产之间的相依结构.同类型的风格资产之间的相依程度比不同类型风格资产之间的相依程度要高;在同一类型的风格资产中,资产规模差距越大的风格资产之间的相依系数就越小.无条件的风格资产收益系列之间的相关性要显著大于有条件的风格资产收益系列之间的相关性;最后根据研究结论提出了降低风格资产组合风险的资产配置建议.     

Copula 函数选择的小波方法

金融资产相依结构研究中选择Copula函数很关键.考虑到相依结构的局部特征差异,利用小波函数的局部自适应能力,将阈值规则引入Copula理论,提出Copula函数的小波收缩估计量,并以此为基准给出参数Copula选择的小波方法.这得到以标普500指数、日经225指数、恒生指数和上证指数为样本的实证支持.进而从不同的时间尺度视角捕捉到股市之间潜在的相依模式.     

基于Copula函数的国际原油价格与股票市场收益的相关性研究

针对国际原油价格与金砖五国股票市场收益之间的相关性问题，使用AR(p)-GARCH(1,1)-Copula模型进行检验。运用广义误差分布(GED)获取收益残差序列，对WTI原油价格和金砖五国股市收益之间的相关性进行实证分析。研究结果表明，国际原油价格与中国股市收益呈现微弱的相关关系，而与其他四国股市收益的相关关系较为明显。用时变SJC Copula模型刻画国际原油价格与金砖五国股票市场收益的相关性最为合适。     

我国股指期货与股市波动相关关系的实证研究

在简要回顾相关文献的基础上,研究了股指期货与股市波动的相关关系。选取2010年4月16日至2016年10月13日的沪深300股指期货及沪深300指数作为研究对象,样本数据分为股指期货推出后短期、中期、中长期和长期四个时间段,建立相关模型进行相关性分析、单位根检验、协整分析和格兰杰因果检验。研究发现,第一,股指期货与股市波动存在高度的正相关性;第二,两者之间存在长期稳定的均衡关系;第三,格兰杰因果检验结果表明,短期和中期的股指期货和股指现货之间并不存在明显的价格引导关系,中长期的股指期货的变化会引起股票市场的波动,而长期的股指期货则与股指现货之间存在着明显的双向因果关系。     

股市系统性风险跨区域溢出分析——来自DCC-GJR-Copula-CoVaR模型的经验证据

考虑到股市系统性风险跨区域溢出问题,构建了多元的DCC-GJR-Copula-CoVaR(Dynamic Conditional Corelational, DCC; Glosten Jagannathan Runkle, GJR; Copula; Conditional Value at risk, CoVaR)模型,利用两步极大似然法估计模型参数,将31个省(直辖市、自治区)注册上市公司的股价省级综合指数,按照国家行政区域合并为10大区域市场股价综合指数.研究结果表明:该模型能度量股市系统性风险跨区域溢出的非对称性,而不同区域的风险贡献度差异较大,风险溢出具有地区差异.这为识别区域系统的重要性及防控股市系统性风险跨区域溢出具有重要的实践价值.     

金融危机对证券市场波动溢出的影响研究

不同证券市场之间的波动存在时变、非对称、非线性相关的特性，尤其是在极端事件影响下，证券市场之间往往会表现出尾部相关的特性。以次贷危机为背景，利用时变Copula模型研究了证券市场间的波动溢出。结果发现无论是金融安全时期还是金融危机时期，均存在美国证券市场对中国证券市场的波动溢出，并且在金融危机期间这种波动溢出效应有增强的趋势。     

基于Markov过程的SW-ARCH模型及其金融VaR计算——以上证综指分析为例

将表现状态转换的Markov过程引入了ARCH模型,通过对上证综指的实证研究,采用SW-ARCH模型并利用非参数核密度估计技术辨识了在全球性金融危机冲击下我国股市出现的大幅异常波动状态,并用Kupiec的失败频率检验法对VaR的准确性进行检验来验证模型的有效性.结果表明:我国股市有着显著的状态转换特征,且重大事件或政策是导致我国股市状态转移的重要原因,基于SW-ARCH模型的VaR能有效反映我国股市风险.     

模拟地下CO2泄漏对土壤微生物群落的短期影响

为研究地质封存CO_2泄漏对土壤微生物的影响,以徐州市褐潮土为研究对象,利用减压阀和可调节流量计控制CO_2的通入,模拟地质封存CO_2泄漏,测定CO_2通气处理前后的土壤理化性质、酶活性以及微生物群落多样性。结果表明:土壤CO_2浓度的增加使土壤pH值降低,最大变化幅度为8.15降至7.29;硝态氮平均含量从通气前的1.01 mg·kg~(-1)上升至4.03 mg·kg~(-1),有机质和有效磷含量变化明显。土壤CO_2浓度的增加抑制了FDA水解酶的活性,各组平均含量从22.69 mg·kg~(-1)·h~(-1)下降至11.25 mg·kg~(-1)·h~(-1),多酚氧化酶活性上升幅度达230%,脲酶活性也表现为上升趋势。土壤CO_2浓度的增加导致Alpha多样性降低,表现为Chao1指数减小,Shannon指数从7.35降低至6.23。在确定种类的微生物中,变形菌门丰度迅速增大,比例从29%增至64%,酸杆菌门比例从20%降至13.25%;在属水平上,Methylophilus、Methylobacillus、Methylovorus三属丰度增大,Gp4、Gp6、Gp7丰度减小,其余菌属变化不明显。CCA分析结果表明,在土壤CO_2浓度增加条件下,硝态氮、脲酶、多酚氧化酶活性的增加,FDA水解酶活性、全磷、有效磷的减少与变形菌门、酸杆菌门物种丰度变化之间存在相关性。     

Antioxidation effect of Carya cathayensis sarg oil

[Objective] The antioxidation effect of Carya cathayensis sarg (CCS) Oil was qualitatively and quantitatively detected.[Method] 50 male mice were divided into 5 groups equally and randomly and among them,the three groups were either negative, or model control, or positive control (ginseng saponins), respectively.Two remaining groups were orally fed with low and high dosages of CCS oil ((9 ml/(kg·d) and (33 ml/(kg·d)), respectively.All groups were injected D galactose through hypodermic except the negative control ones which were only treated with equals amount of distilled water.The superoxide dismutase (SOD), maleic dialdehyde(MDA) and monoamine oxidase(MAO) were analyzed with blood sample and brain tissue 42 days post treatment.[Result] It was showed that the activity of SOD enzyme was increased in the CCS oil groups, while MDA and MAO content were decreased in the CCS oil groups compared with that of other groups with significance observed in the group fed with high dose of CCS oil.[Conclusion] The result indicated that the CCS oil has the ability of antioxidation and is useful to human health.     

棉花红铃虫管理专家系统及其实现

棉花红铃虫管理专家系统是一个集预测、诊断与咨询于一体的复杂系统,可直接指导农民生产实践.该专家系统将数学模型、历史数据资料和专家实践经验知识融为一体,采用PROLOG与C语言的接口.知识库知识采用带有变量的知识表示.系统由数据资料管理模块、知识库、模型库、推理机、知识获取模块、解释机构和人机接口所组成.经实践验证预测害虫发生准确率达90％以上.     

Study on Multi-variables Decoupled Fuzzy Controller for Confined Pig House in Northern China

In winter, the confined pig house of northern China is severe. The environment variables are nonlinear, time-varying and coupled, which seriously affect the health of pigs and the qualities of the meat. In order to solve the problem multi-variables coupling, a multi-variables decoupled fuzzy logic control method was proposed. Two fuzzy logic controllers were designed based on fuzzy logic theory. The fans, heaters and humidifiers were used to control temperature, humidity and ammonia. The reductions of temperature and humidity caused by ventilating were compensated by heaters and humidifiers respectively which realized the multivariables decoupling. The proposed methods were validated through theoretical, experimental and simulation analysis. The results suggested that the methods were able to regulate the confined pig house environment effectively. In addition, comparing to the manual regulation, the proposed methods could reduce 19% power consumption as well.     

Fuzzy logic control of a multispectral imaging sensor for in-field plant sensing

The development of an in-field plant sensing system for a site-specific application can protect the environment from excessive chemicals and save management cost while maintaining productivity. A multi-spectral imaging sensor has been introduced and widely used for in-field plant sensing. In order for a robust performance of the spectral imaging sensor under changes in ambient illumination, image quality must be maintained for proper spectral image analysis. Image formation that is affected by camera parameters was identified, and a controller was developed to compensate varying image intensity and to obtain the desired image quality. A fuzzy logic control algorithm was applied to automatically adjust the camera exposure and gain to control image brightness within a targeted gray level. Slow convergence and oscillation were regulated by dynamic membership functions with different weights in each image channel. Images affected by illumination disturbance quickly converged into a desired brightness image within a maximum of five iterations over the entire range of camera gains in all three spectral image channels. An application of in-field plant sensing using the fuzzy logic image controller was evaluated on corn crops for nitrogen detection. The normalized spectral response of the sensor was inversely correlated to a chlorophyll meter with −0.93 and −0.88 in red and green channels, respectively. The development of an image quality controller using fuzzy logic enhanced the reliable performance of the in-field plant sensing system.     

Widescale testing of the Crop-meter for site-specific farming

A sensor for measuring crop biomass density has been designed and developed to meet the demands for practical use in site-specific farming. The mechanical sensor named ‘Crop-meter’ is based on the pendulum principle. The suitability and measuring stability of the Crop-meter has been confirmed under field conditions in different regions of Germany. Significant correlations were obtained between Crop-meter signals and soil electrical conductivity (R ²=0.16−0.66) and grain yield (R ²=0.42−0.57). To test the suitability of the Crop-meter for site-specific management, it was used to control variable application rates for nitrogen fertiliser, growth regulators and fungicides in real time. A small increase in yield (3.1%) as well as reduced application rates for agrochemicals (14.6% nitrogen fertilisers; 23.1% fungicides and growth regulators) were proved in large-scale trials.     

基于PLC和云平台的鹅孵化机监控系统设计与试验

【目的】为了提高鹅种蛋孵化性能,针对现有鹅孵化机孵化过程自动化程度低、温度波动大、鲁棒性差,现场操作复杂等不足,设计了一种基于可编程逻辑控制器(Programmable logic controller,PLC)和云平台的鹅孵化机监控系统。【方法】根据鹅种蛋孵化工艺要求和鹅孵化机工作原理,采用PLC作为主控制器设计了系统的硬件电路和软件程序,实现孵化机温度、湿度、翻蛋和喷水晾蛋的自动控制,利用触摸屏和组态软件设计了孵化机现场监控的人机交互界面,并利用通用分组无线业务(General packet radio service,GPRS)智能网关、云平台服务器和移动端设计了远程监控系统。系统工作时,GPRS智能网关读取PLC中的存储数据,通过4G/5G网将数据上传至云平台服务器,移动端通过微信公众号、APP或网页可以直接访问和下载云平台服务器中的数据,并以图表形式显示出来。【结果】该监控系统运行稳定、状态良好;孵化过程中的温度采样数据鲁棒性高,100%达到控制要求;自动控制有助于提高鹅孵化机自动化水平;孵化生产试验结果表明,狮头鹅受精蛋平均孵化率为87.84%,比现有记载最高纪录高1.44...     

遥控自动立木整枝机运动控制系统

正确的控制逻辑是自动立木整枝机运动控制系统的关键技术.该文根据作业要求,研制了基于复杂可编程逻辑器件的自动立木整枝机运动控制系统.该系统采用自制的新型电动机位置动态检测装置,通过复杂数字逻辑运算及相应的闭环控制驱动电路,实现对人工林自动立木整枝机控制信号的分组、实时控制.该运动控制系统设计合理、控制逻辑准确,已成功应用于BSR Z23 001A人工林自动立木整枝机,工作可靠,使用效果良好.      

Real-time,volatile-detection-assisted control for microwave drying

A real-time, volatile-detection-assisted control system was designed for microwave drying. Detected volatile signals were integrated to a fuzzy logic algorithm to determine the drying temperature. A phase controller was used to automatically and continuously adjust the microwave power. A data acquisition unit with developed program was employed to integrate the entire control. Carrot samples were used in system tests. The results showed that the designed system could successfully achieve the desired temperature, power, and volatiles control and lead to acceptable product's quality.     

基于PLC的拔抛秧机械手监控系统设计与试验

目的 设计一套拔抛秧机械手监控系统,以提高拔抛秧机械手设备的自动化和信息化水平。方法 根据拔抛秧机械手工作原理,采用可编程控制器(Programmable logic controller,PLC)作为主控单元设计了系统的硬件电路和软件程序,采用触摸屏和组态软件设计了拔抛秧机械手的人机交互监控界面,并采用GRM530通讯模块、云服务器、Android手机和Android Studio软件设计了远程监控系统手机APP。该监控系统工作时,GRM530通讯模块读取PLC中指定的存储器数据,通过4G网或WIFI将数据上传到云服务器内,Android手机APP可直接访问并下载该云服务器中的数据,最后在APP中可视化地呈现出来。结果 该监控系统工作稳定可靠,远程通信测试重复10次试验的丢包率均为0,平均时延为25 ms,表明Android手机APP客户端和拔抛秧机械手可以实现稳定可靠的双向通信。该系统的数据传输是双向的,人机交互功能正常,触摸屏和Android手机APP均能精准地反馈设备的工作状态和工作数据,用户可以通过Android手机APP对PLC发送控制指令,实现整个系统的监控一体化,远程控制指令响应延时低,最高响应延时不超过0.63 s。结论 该拔抛秧机械手监控系统可以对拔抛秧机械手工作状态和工作数据进行远程实时监控,具有良好的人机交互界面,对促进信息化与农机装备的深度融合具有一定指导意义。