基于关键节点与关键路径的专利集群网络演进研究

专利作为技术和知识的重要载体，是研究技术演进和产业发展的重要信息源。目前缺乏针对专利集群网络中关键节点与关键路径中节点的比较分析和技术知识挖掘。构建基于关键节点和关键路径的专利集群网络演进模型，从两个层面综合分析技术演进特征。检索德温特数据库(Derwent Innovation Index)得到碳化硅肖特基势垒二极管（SiC-SBD）相关专利作为实证数据，时间跨度为1986-2017年。结果表明，SiC-SBD专利集群网络经历了萌芽期、成长期、成熟期和衰退期，其中，萌芽期专利主要涉及基础技术，成长期为器件结构，以完善器件结构、改进二极管性能为主要研究方向。近年来SiC-SBD专利年增长率下降，技术发展速度放缓，专利价值更多体现在其商业价值上。SiC-SBD专利集群网络关键节点与关键路径中节点重合度较高，核心专利识别可通过多视角分析得到。通过关键节点与关键路径分析专利集群网络演进过程，有助于更全面呈现技术演进过程，为决策者识别核心专利、预测技术发展提供参考。     

区域知识产权保护发展的空间格局及结构体系研究

以我国各省知识产权保护制度为研究对象，创新性地将探索性空间数据分析方法与社会网络分析方法相结合，基于地理邻近视角，验证了区域知识产权保护的空间相关性、空间集聚特征和空间溢出效应。同时，突破地理近邻效应的局限，解析区域知识产权保护的空间关联特征。结果表明：我国各省知识产权保护具有全局自相关性，相似地区间存在空间集聚效应，不同发展程度地区的空间关联性质不同；网络化后的区域知识产权保护各节点间联系紧密、网络结构稳定，并且可以确定核心行动者和边缘行动者角色；长三角、珠三角、环渤海等较发达地区与其它地区之间存在较多溢出关系。     

国家高新区设立能够提升城市全要素生产率吗？——基于261个地级市TFP分解数据的路径分析

国家高新区是培育经济增长新动能，实现区域经济高质量发展的重要政策载体，文章利用2001-2014年我国261个城市面板数据，通过渐进双重差分法研究国家高新区设立对城市全要素生产率的影响。研究发现：研究期内国家高新区的设立对城市全要素生产率造成显著的负面影响；从TFP的分解项来看，高新区设立促进了所在城市规模效率提高，却抑制了技术进步和技术效率提高；异质性分析结果表明上述作用具有显著城市等级异质性，在高行政等级城市设立高新区对城市全要素生产率具有促进作用。进一步运用工业企业数据库、微观土地转让数据、城市专利数据等进行机制分析发现，企业间资源错配和土地价格扭曲降低了技术效率，而技术创新下降和产业升级钝化是抑制技术进步的主要机制。     

基于标准数据的创新程度提升路径研究

创新程度在资源配置中的作用日趋明显，但目前创新程度常以专利作为测量值。随着标准在产业发展中引导性增强，作为创新重要产出的标准在创新程度提升中的地位日渐凸显。提出一个以标准数据为依据，通过对标准创新程度值的测量，结合国际国内创新程度四分图模型，研究具体领域创新程度提升路径。以信息技术应用领域标准为分析对象，结合国际标准化组织颁布标准和中国标准，确定信息技术在各应用领域创新现状。结果显示：信息技术在办公系统和银行业务两个领域应用的国际国内创新程度都很低，应在完成产业升级后逐渐淘汰；其在健康关怀领域应用的国际发展前景良好但国内创新程度很低，是重点研究领域。随后，对信息技术在健康关怀领域应用的国际和国内标准具体内容进行对比分析，发现中国与国际发展存在差距，并以国际国内创新程度为依据对位于四分图不同区域的信息技术应用领域创新程度提升提出合理建议。     

COVID19: Holiday intentions during a pandemic

The travel, tourism and hospitality industries have been the worst affected of the world's major economic sectors during the COVID19 pandemic, which has had a devastating effect on both destinations and organisations. Drawing from a sample (N = 385) of adult permanent residents of Athens, Greece, the study examines the impact of COVID19 upon holiday intention. The chaordic systems are evaluated through the use of fuzzy-set Qualitative Comparative Analysis, whilst the study also used Necessary Condition Analysis for the calculation of the size effects of the examined conditions. The findings reveal two sufficient complex configurations leading to holiday intention: (i) holiday risks, and (ii) impact of COVID19. Based on the results, the article also offers a set of managerial implications. The contribution of the study is to both theoretical and methodological tourism domains.     

The Impact of Public Expenditure and International Trade on Agricultural Productivity in China

The “industry nurturing agriculture” reforms and World Trade Organization accession led to dramatic growth in public expenditure and international trade in China’s agricultural sector. This article aims to estimate the effects of public expenditure and trade on agricultural productivity in China for 2004–2015. A semi-parametric production function with shape constraints is introduced to derive more accurate productivity before the productivity determinants are analyzed with an emphasis on public expenditure and trade. The empirical result shows that public expenditure and exports can effectively improve agricultural productivity, while imports have no significant effects. Policy implications are discussed in the context of supply-side reforms.     

Is there a diversification “cost” of Shari’ah compliance? Empirical evidence from Malaysian equities

Islamic equity portfolios work with a smaller investment universe given the filtering of non-Shari’ah compliant stocks. It has been theoretically argued that this culminates in suboptimal portfolio diversification, which in turn adversely affects risk-adjusted returns. We offer empirical evidence that such a conceived portfolio diversification “penalty” is far from a foregone conclusion, at least empirically. Our results tend to indicate that Islamic portfolios are not invariably handicapped in terms of portfolio diversification. We also explored dimensions that may account for differences in the relative investment performance between Islamic and conventional portfolios, such as portfolio constraints, short selling and market conditions. We believe this paper is among the first to apply substantial empirical analysis specifically with respect to the portfolio diversification perspective on Islamic equity investments.     

The long overhang of bad decisions in agro-industrial development: Sugar and tomato paste in Ghana

In theory, learning from past mistakes should result in adapted and improved development policy. However policy learning can be difficult to achieve, and the link between learning and policy change is neither direct nor immediate. In this study we look at learning in agro-industrial policy in Ghana, by tracing the interest in sugar production and tomato processing over six decades. Specifically we ask why four failed factories established in the early 1960s have continued to play central roles in both policy and public discourse. Using policy documents, academic material, and the popular press, we show that Ghana’s policy focus on sugar production and tomato processing has endured, despite the fact that the factories were misconceived, poorly sited, ill-equipped and poorly managed. Indeed, the political ideas that underpinned the establishment of these factories in the early days of independence can be seen in the current One District, One Factory policy. We suggest that it is their symbolic and political value, not their economic value, which keeps the discussion around these factories alive. Even when shut down, they are a physical manifestation of historic commitments by the state, and as such they guarantee the attention of politicians, and hold out hope of a next re-launch. Unfortunately as long as the factories continue to be incorporated into each new generation of agro-industrial policy, it is difficult for any alternatives to gain traction. This analysis highlights the very long overhang of bad decisions, particularly when they are associated with physical infrastructure. Learning from past mistakes will only happen if the short-term political cost of turning policy learning into policy action can be overcome.     

Functional Itô calculus†

We extend some results of the Itô calculus to functionals of the current path of a process to reflect the fact that often the impact of randomness is cumulative and depends on the history of the process, not merely on its current value. We express the differential of the functional in terms of adequately defined partial derivatives to obtain an Itô formula. We develop an extension of the Feynman-Kac formula to the functional case and an explicit expression of the integrand in the Martingale Representation Theorem. We establish that under certain conditions, even path dependent options prices satisfy a partial differential equation in a local sense. We exploit this fact to find an expression of the price difference between two models and compute variational derivatives with respect to the volatility surface.     

Persistence of Price–Cost Margin and Technical Efficiency in the Indonesian Food and Beverage Industry

Abstract

This research investigates the persistence of price–cost margin (PCM) and technical efficiency (TE) of firms and the relation between these two factors in 44 subsectors of the Indonesian food and beverage industry in the period 1980–2014. Data envelopment analysis with a bootstrapping approach is applied to estimate TE. An autoregressive model, accounting for endogeneity, is applied to estimate the persistence coefficients of PCM and TE. A cross-sectional regression model is also applied to estimate the relation between the persistence of the PCM and the persistence of TE. The results show that for these food and beverage firms, high PCM and low TE persist. Furthermore, the persistence of PCM negatively affects the persistence of TE in the industry.