Dynamic no-good-deal pricing measures and extension theorems for linear operators on L ∞

In an L ^∞-framework, we present majorant-preserving and sandwich-preserving extension theorems for linear operators. These results are then applied to price systems derived by a reasonable restriction of the class of applicable equivalent martingale measures. Our results prove the existence of a no-good-deal pricing measure for price systems consistent with bounds on the Sharpe ratio. We treat both discrete- and continuous-time market models. Within this study we present definitions of no-good-deal pricing measures that are equivalent to the existing ones and extend them to discrete-time models. We introduce the corresponding version of dynamic no-good-deal pricing measures in the continuous-time setting.     

OUTPUT FLUCTUATIONS PERSISTENCE: DO CYCLICAL SHOCKS MATTER?

The aim of this paper is to identify the different sources of persistence of output fluctuations. We propose an unobserved components model that allows us to decompose GDP series into a trend component and a cyclical component. We let the drift of the trend component switch between different regimes according to a first‐order Markov process. To calculate an appropriate p‐value for a test of linearity we propose a bootstrap procedure, which allows for general forms of heteroscedasticity. The performance of the bootstrap is checked by means of a Monte Carlo simulation. Our study concerns the USA. We find that cyclical shocks appear to play an important role on the observed persistence of output.     

Old Wine in New Bottles: Patenting Propensity

Journal of Industry, Competition and Trade - Although patenting propensity has been an old topic, our understanding of it is still fragmentary due to the complexity in the decision-making and the...     

相关行业上市公司政府补助对铁路公益性补贴的启示

针对航空运输、电信、石油等国家基础设施行业,通过分析这些行业上市公司的政府补助情况,在借鉴相关行业政府补助实践的基础上,提出建立铁路公益性运输发展基金,由中央政府和地方政府共同承担铁路公益性补贴责任的政策建议,同时认为铁路运输企业除争取公益性补贴外,还应争取税收优惠、专项补贴等其他补贴政策。     

WIC Participation and Relative Quality of Household Food Purchases: Evidence from FoodAPS

We examine the effect of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on the quality of household food purchases using the National Household Food Acquisition and Purchase Survey (FoodAPS) and propensity score matching. A healthy purchasing index (HPI) is used to measure nutritional quality of household food purchases. WIC foods explain the improvement in quality of food purchases, not self‐selection of more nutrition‐conscious households into the program. The improvement in purchase quality was driven entirely by WIC participating households who redeemed WIC foods during the interview week. There was no significant difference between WIC participants who did not redeem WIC foods and eligible nonparticipants. In this sample, there is no evidence that lack of access to clinics has adverse effects on participation nor is there evidence that HPI depends on supermarket access. A supervised machine learning process supports our main conclusion on the importance of WIC foods.     

跨文化交际对应用型本科英语口语教学的影响

跨文化交际是指不同文化背景的人们之间的交际.外语教学的根本目的是实现跨文化交际,因此,应重视跨文化交际在口语能力教育上的重要作用,使学生了解语言与文化之间的关系,注重培养跨文化的意识,熟知中外文化异同与语言表达的形式特点,避免交际中出现语法应用正确却产生文化冲突的现象.     

考虑现实约束的不确定投资组合研究

作为实现财富增值保值的有效手段,投资组合引起了实务界和学术界的广泛关注。然而,以往研究大多忽略了金融市场的复杂性、外部因素的不确定性和历史数据的缺失性。为更准确刻画金融市场的现实状况、求解最优投资组合,本文引入不确定变量来描述证券收益率,进而构建包含交易成本、整手交易、流动性风险、交易上下限和行业分散化等现实约束的证券不确定投资组合模型;同时采用遗传算法进行计算,并代入模拟交易数据对比有现实约束和无现实约束投资组合模型的最优解。研究结果表明,引入现实约束条件后,最优投资组合发生了变化,期望收益率显著下降。上述研究结论带来的启示:对于证券投资者而言,在进行投资交易时,应充分考虑交易成本和不确定性风险,确保将投资风险限制在可控的范围之内;对于证券监管机构而言,应加强对证券市场的监督与管理,尤其是系统重要性机构,防范和化解流动性风险和不确定性风险。     

比利时传染病防控应急体系与应急措施

2019新型冠状病毒肺炎疫情暴发给中国乃至全球公共卫生带来了重大挑战。比利时在传染病防控方面具有丰富的经验。本研究通过检索相关文献及政策资料,回顾比利时针对传染性疾病的应急管理的法律法规、组织框架、经费、应急系统,并以比利时2014年埃博拉疫情防控为例,总结比利时防控传染病政策和措施的成功经验。在此基础上,针对2019冠状病毒提出防治措施建议:设立永久性传染病风险评估工作组;利用大数据构建突发传染病主动防控云平台;定期开展针对突发传染病防控的相关演习等。     

基于射频指纹技术的卫星信号个体识别方法

现有射频指纹识别研究主要集中于射频指纹产生及提取的通信机理,忽略了实际应用中信号采集数据的清洗筛分、识别算法模型的效率等工程性问题。为此,分析了卫星通信号的载波信息提取的原理与方法,并针对现有射频指纹方法的不足,围绕卫星信号识别领域,利用海量采集的射频指纹数据,深入研究基于自组织神经网络的射频指纹识别算法,提出了对应的算法模型,并与现有常见的无监督算法进行了比较。结果表明,所提方法可以取得更优的算法聚类效果和时间开销,可作为设计实现卫星频谱管理系统的基础。