Market Moods and Network Dynamics of Stock Returns: The Bipolar Behavior

The authors show that a simple mood-separable preference in a network study of stock returns captures a variety of stylized facts regarding stocks’ provisional (ab)normal behavior. These behaviors are articulated in a multistate complete Euclidean network model that specifies the existence, direction, and magnitude of a self-organized dynamics for each individual stock during abnormal market moods. In the empirical setting, the authors apply suggested model along with 2 established visual approaches (multidimensional scaling and agglomerative hierarchical clustering) for benchmark purposes. Results reveal different levels of erratic return dynamics for each stock and the entire market in different abnormal market moods. The authors model and interpret these self-organized dynamics as evidence of stocks’ and market’s bipolar behavior.     

Effect of proximity on recombination innovation in R&D collaboration: an empirical analysis

Recombination innovation is a process of creatively combining different knowledge domains in an invention. Recombination innovation in R&D collaboration – joint recombination process, which is integration of the organisation’s internal knowledge with the partner’s new knowledge, serves as the stepping stone of the knowledge search in the technological space. This paper tries to illuminate how different dimensions of proximity of the collaborating partners affect the probability of the collaborative innovation to be recombination innovation. Our result shows that technological proximity has a negative effect on joint recombination innovation. Geographical proximity has an inverted U-shaped effect on joint recombination innovation. The positive effect of organisational proximity on joint recombination innovation is not supported.     

Further remarks on totally ordered representable subsets of Euclidean space

We introduce the property of ? -norm-boundedness on totally ordered subsets of Euclidean spaces. We show that when a closed subset X of the Euclidean space ⁿ, endowed with a continuous total order ?, is ? -norm-bounded, the order topology and the induced Euclidean topology must coincide on X. This generalizes a recent result by Beardon, proved on connected totally ordered subsets of Euclidean space, because on totally ordered closed subsets of ⁿ connectedness is a particular case of ? -norm-boundedness. We also analyze necessary and sufficient conditions for the coincidence of both topologies, and discuss some extension to the infinite-dimensional context.     

校所组织邻近性对联培博士生社会资本作用机制的实证研究

采用问卷法对10个高校与工程院所联合培养博士生项目的175名博士生进行调查,分析了两类校所组织邻近性、合作程度对联培博士生社会资本的影响。结构方程模型分析表明,制度邻近性对博士生的高校社会资本产生正向直接效应,认知邻近性对校所双方的合作程度、联培博士生的高校社会资本、院所社会资本皆存在显著的正向效应,而合作程度在认知邻近性与院所社会资本关系中具有中介作用。基于此,提出相应建议和措施以推进校所联培项目的完善与发展。     

基于Harris和SIFT的特征匹配算法

为了克服传统的局部特征匹配算法对图像的尺寸和旋转比较敏感的缺点,文章提出了一种基于Harris和SIFT的特征匹配算法。该算法首先进行Harris角点提取,利用圆的旋转不变性和多维向量来构造SIFT特征描述子,然后利用极线约束降低对匹配点的搜索空间,最后度量特征描述子之间的欧氏距离,运用双向匹配技术得到最终的匹配结果。实验结果表明,该算法能提高匹配精度,减少匹配时间。     

Culture and knowledge spillovers in Europe: New perspectives for innovation and convergence policies?

Using European patent citations, we examine the geography of knowledge flows within Europe. We aim at analysing whether technologies flow more rapidly among countries that share similar economic, geographic, technological or cultural characteristics. The specificity of our approach consists in integrating indicators of culture and cultural similarity. The empirical results suggest that cultural distance has only a mitigated and moderate impact in comparison with other proximities. On the contrary, cultural belonging is shown to influence the geography of knowledge flows and innovation. More precisely, if some populations develop thanks to external knowledge exploitation, others rather explore internal new ideas and knowledge. In such a differentiated context (we find three types of culture), the efficiency of innovative policy seems to be culturally dependent.     

弹载数据链系统实时RS译码器设计

为了提高传输可靠性,各种差错控制编码技术已经被广泛应用在弹载武器数据链系统中。RS(Reed-Solomon)码具有很强的抗错误能力,且码长可以灵活控制,十分适合在弹载数据链系统中应用。设计了三种不同码率的RS码,并在修正的欧几里德算法基础上进一步优化,实现了一种新型RS码实时译码器。为减少系统复杂度,该译码器复用4组基本运算单元以完成错误位置多项式和错误值多项式计算,同时也没有插入额外的流水线结构,译码过程所需的GF(28)域求逆运算则通过查找表结构实现。整个设计已经在Altera公司的EP2S15器件上通过综合和验证,与同类设计相比占用资源大大减少,适合于高可靠性导弹数据链系统开发。     

创新网络空间格局形成机理及演化分析

针对创新网络空间格局如何形成及演化的问题,基于多元邻近视角剖析创新网络空间格局形成机理,运用Agent理论设计仿真算法,并基于Netlogo构建创新网络空间格局演化仿真平台。通过模拟实验发现：①多元邻近更有利于创新网络区域内、外部合作共生,且（跨区、内部）合作边数与区域面积、毗邻距离呈正、负相关;②社会邻近或技术邻近更有利于创新网络产生（绝对）空间集聚,且集聚态势与区域位置中心性呈正相关;③创新网络空间格局呈现随机型至斑块型（或均匀型）的动态演化趋势,且社会邻近或技术邻近更有利于创新网络产生均匀型空间格局,地理邻近或多元邻近更有利于创新网络产生斑块型空间格局;④地理因素作用下的创新网络（空间格局）仍保持幂律分布特性;⑤斑块型空间格局的创新绩效高于均匀型,且多元邻近下斑块型空间格局的创新绩效最高。     

平台侧位置指纹定位系统中接收端问题的优化

当前室内位置指纹定位系统主要用于对移动端的定位。借鉴其定位机理,研究了对无线电发射端的定位,属于平台侧位置指纹定位系统。从部署接收端的位置以减小定位误差的角度出发,提出了增大参考点之间欧式距离确定接收端位置的方案。同时,提出利用覆盖率的概念确定定位区间的接收端个数以满足区间定位的需求。建立了接收端位置及个数优化问题的数学模型,并用遗传算法和全覆盖原则对优化问题进行求解,给出了优化问题的实现流程。针对不同空间,对优化问题进行了仿真,比较了经验布置接收端和优化布置接收端的定位结果误差及接收端是否满足全覆盖的定位结果误差,验证了所提方法的合理性,对定位前部署接收端的个数和位置有一定的指导意义。     

How rich countries became rich and why poor countries remain poor: It's the economic structure…duh!

Becoming a rich country requires being able to produce and export commodities that embody certain characteristics. We classify 779 commodities (exported) according to two dimensions: (1) sophistication (measured by the income content of the products exported) and (2) connectivity to other products (measured by how easy it is to ‘jump’ into other potential exports). We identify 88 “good” products (highly sophisticated and well connected products), 93 “bad” products (unsophisticated and poorly connected products), and 598 “middle” products. Then, we categorize 154 countries into four groups according to the export share of each of these three types of products. There are 21 countries whose export baskets contain at least 15% of “good” products; 41 countries with a significant share of relatively sophisticated and well connected products; 50 countries with a significant share of relatively unsophisticated and not well connected products; and 42 countries whose export basket contains at least 15% of “bad” products.