有线电视光缆传输系统指标的分析与设计

介绍了有线电视网中ＡＭ 光缆干线传输综合指标的分析与设计。由于ＤＦＢ激光器间的非线性有较大差异,故引入了光链路这一参数。当把这一参数引入有线电视光缆干线设计时,可根据有线电视光缆系统不同传输距离、光接点的分配指标和光缆干线传输系统的实际情况,计算光链路损耗,以确定光端设备的选型,从而进一步确定光缆干线传输系统的设计,使得有线电视总系统指标给以保证     

Social Innovation in an Interconnected World: Introduction to the Special Issue

This introduction provides an overview of the special issue and identifies the need for continued work in the area of social innovation, which seeks to create social value and progress and engages multiple stakeholders. Our special issue highlights various levels and stakeholders involved in the process and outcomes of social innovation. While mainstream innovation, which has been traditionally driven by profit maximization motivations, tends to create winners and losers, social innovation that focuses on redistribution of knowledge, discovery, and cocreation changes the key assumptions and logics of the conventional innovation theory. This introduction first briefly outlines current social innovation literature, presents the contributions created in this special issue, and concludes with the identification of three priorities (or needs) for social innovation researchers.     

外国石油公司动态

(2009年11月) 投资与合作 塞尔维亚天然气公司和Gazprom将组建合资公司 塞尔维亚国家天然气公司(Srbijagas)和俄罗斯天然气工业股份公司(Gazprom)将组建一家合资公司来共同建造塞尔维亚境内段的南流管道.Gazprom和Srbijagas将分别拥有合资公司51%和49%的股份.     

Management Guidance Pre‐ and Post‐Restatement

We examine whether the quality of restating firms’ management guidance differs in periods before and after restatement announcements. While characteristics of restating firms and the consequences of restatement have been a central topic in accounting and auditing research, the quality of management guidance around restatements is less well understood. We consider two competing characterizations of the link between management forecast accuracy and bias and restatement (an event that tends to signal poor financial controls): “Forecast–Opportunism Explanation” and “Forecast–Ability Explanation”. Under the Forecast–Opportunism Explanation, pre‐restatement weaknesses in financial controls enable managers to manipulate earnings toward forecasts and to meet or exceed opportunistically biased forecasts, and the post‐restatement strengthening of financial controls constrains opportunistic behavior. Under the Forecast–Ability Explanation, pre‐restatement weaknesses in financial controls impede managers’ ability to issue accurate forecasts, and post‐restatement improvements remove impediments so that the accuracy of forecasts improves; forecast bias remains unaffected. Evidence indicates that before a restatement, restating firms’ forecasts are more accurate and relatively more downwardly biased than control firms’ forecasts. Post‐restatement, restating firms have less accurate and less downwardly biased management guidance. Our overall results are consistent with the Forecast–Opportunism Explanation.     

把脉经济过热

“目前经济运行中存在的主要问题,仍然是固定资产投资增长过快、货币信贷投放过多,特别是结构性矛盾突出,能源资源和环境压力增大。”温家宝总理在2006年6月14日国务院常务工作会议上这样指出。无疑,理解这些顽症的形成机制、进而妥善地加以解决,是经济发展的当务之急。     

我国环保设备制造业产业布局的实证研究——长三角地区的发展对策

我国环保设备制造业存在很大的发展空间,本文主要运用区位商分析法、评价投入和产出相对效率的数据包络分析法（DEA）,结合各地区、城市和企业的市场占有率指标,对我国环保设备制造业的区域分布特征、产业专业化程度、产业效率以及市场绩效方面的现状进行实证,得出我国环保设备制造业的产业分布图,并从区域分工和协作的角度提出长三角地区两省一市环保设备制造业的发展对策。     

新型集体经济的基本理念和改革实践

本文从理论和实际的结合上,对我国发展集体经济的认识与实践进行历史和现实的思考,阐述了以新型集体经济的理念改造传统集体企业,发展多种形式的集体经济,坚持和完善社会主义初级阶段的基本经济制度,推进中国特色社会主义事业发展的理论思路。     

数字经济发展对中国绿色生态效率的影响研究——基于双向固定效应模型

实现数字经济与城市生态韧性协调发展是推动城镇化高质量发展与美丽城市建设的有效路径之一。在构建数字经济与城市生态韧性评估指标体系的基础上,运用熵权法、TOPSIS模型、耦合协调模型与PLSR模型,对2012—2021年珠三角地区各城市数字经济发展、城市生态韧性的时空动态特征及其耦合协调与影响关系进行实证研究。结果表明：（1）珠三角地区各城市数字经济发展经历了缓慢发展期和蓬勃发展期两个阶段,政策引领是数字经济发展的主要推动力,各城市数字经济发展水平呈现“梯队式”发展趋势。（2）珠三角地区各城市生态韧性水平在空间上呈现“中心高周边低”的特征,广州、深圳与东莞的城市生态韧性水平高于其他城市。（3）珠三角地区数字经济发展对城市生态韧性提升具有显著的赋能作用,并且数字经济发展对不同城市的赋能效应具有显著差异,数字基础设施、数字产业化是推动珠三角地区城市生态韧性提升的最主要因素。（4）珠三角地区各城市数字经济与城市生态韧性的耦合协调程度呈现“两超一强多弱”状态,仅广州、深圳两城处于高度耦合协调阶段。基于上述研究结论,文章提出未来珠三角地区需要坚持政策引领,着力推动二三线城市数字经济的发展;发挥生态优势,巩固发展各城市的特色生态产业;重视中心城市的引领作用,助推周边城市数字经济与生态环境协调发展。

     

Can negative interest rates really affect option pricing? Empirical evidence from an explicitly solvable stochastic volatility model

The profound financial crisis generated by the collapse of Lehman Brothers and the European sovereign debt crisis in 2011 have caused negative values of government bond yields both in the USA and in the EURO area. This paper investigates whether the use of models which allow for negative interest rates can improve option pricing and implied volatility forecasting. This is done with special attention to foreign exchange and index options. To this end, we carried out an empirical analysis on the prices of call and put options on the US S&P 500 index and Eurodollar futures using a generalization of the Heston model in the stochastic interest rate framework. Specifically, the dynamics of the option’s underlying asset is described by two factors: a stochastic variance and a stochastic interest rate. The volatility is not allowed to be negative, but the interest rate is. Explicit formulas for the transition probability density function and moments are derived. These formulas are used to estimate the model parameters efficiently. Three empirical analyses are illustrated. The first two show that the use of models which allow for negative interest rates can efficiently reproduce implied volatility and forecast option prices (i.e. S&P index and foreign exchange options). The last studies how the US three-month government bond yield affects the US S&P 500 index.