Multilayer financial networks and systemic importance: Evidence from China

In this paper, we develop a multilayer network structure and reveal the relationship between network structure and systemic risk. Unlike many previous studies, our model considers both liability and cross-holding of shares between financial institutions simultaneously. We propose a new systemic risk measurement by exploring the dynamic mechanism of financial contagion in the multilayer network. We display the network structure of Chinese financial institutions, including connectivity and diversity, and identify the systemic importance of them. We demonstrate that the multilayer network plays a non-linear role in financial risk spreading. Using the panel regression model and several experiment evidences, we show that the systemic risk can be explained more effectively by the linkage diversity more than the connectivity at both the institutional level and the system level. Our results highlight the importance of considering contagion mechanisms that go beyond a simple single-layer network structure.     

The role of London airports in providing connectivity for the UK: regional dependence on foreign hubs

In a context of ongoing debate about the future UK aviation policy and its implications for regional economic development, this paper discusses the role of London Heathrow and the South East airports in providing connectivity for the UK, with particular focus on the international markets that originate from regional UK airports. Using an MIDT dataset of worldwide passenger itineraries served by the European airport network during May 2013, we first establish whether London Heathrow can currently be considered the most important hub for the UK, in terms of traffic generation, connectivity, and centrality, while also measuring the dependence of UK regions on foreign airports and airlines to remain connected with the rest of the world. Results show that, despite the competition, London Heathrow benefits from its massive traffic generation to remain the most central gateway for overall UK air transport markets. However, when only regional markets are considered, significant dependence on foreign hubs appears in many destinations, particularly to Asia–Pacific or the BRIC countries where above 80% of passengers use transfer flights. These results fit nicely with the observed trends of seat de-concentration and hub-bypassing in the airline industry. While dependence on foreign hubs can be interpreted as a sign of vulnerability, there is also the argument that bypassing Heathrow allows regional airports to develop new markets and reduce the level of congestion in the London airport system.     

Arc routing problems to restore connectivity of a road network

After a disaster, restoring accessibility in the affected area is critical for response operations. We study two arc routing problems for clearing blocked roads. The first problem minimizes the time to reconnect the road network, while the second maximizes the total benefit gained by reconnecting network components within a time limit. For each problem, we develop a mixed integer programming formulation and two versions of a heuristic algorithm. We conduct computational experiments on Istanbul data and instances adapted from the literature. The heuristics achieve near-optimal or optimal solutions quickly in most of the tested instances.     

DEFINING AND OPERATIONALIZING SUPPLY CHAIN PROCESS INTEGRATION

Integration has been recognized as critical to successful supply chain management. However, an extensive literature review revealed no consensus in its conceptualization. The current study attempts to address this research gap by providing a better definition and operationalization of supply chain process integration. With empirical support, it is proposed that internal and external supply chain process integration should be treated as two separate constructs, each comprised of two dimensions: connectivity and simplification.     

中国对外直接投资有助于沿线国家绿色技术创新吗——基于“一带一路”沿线国家数据的检验

“一带一路”沿线国家的绿色转型给中国承担新使命、促进国内国际双循环和绿色发展创造了新机遇。基于中国对外直接投资（OFDI）特征,研究其对“一带一路”沿线国家绿色技术创新的影响及作用机制。研究发现,中国OFDI主要通过绿色技术溢出机制、增长机制影响“一带一路”沿线国家绿色技术创新;该绿色技术创新效应随着互联互通合作水平提升而显著增强,且对沿线国家绿色技术创新的改善效果主要体现在高收入组国家。     

Landscape fragmentation in Mediterranean Europe: A comparative approach

Maintaining ecosystem continuity has become a central element in spatial planning policies. Several authors acknowledge the environmental, also known as landscape, fragmentation due to human action as one of the main causes which have negative effects on biodiversity. The phenomenon consists of the transformation of larger patches of habitat in smaller ones, or fragments, which tend to be more isolated than in the original condition. It is extremely evident in urban areas, including settlements and various transport and mobility infrastructures, whose main ecological effects include loss of habitat, increased mortality of plants, and isolation of animal and vegetal species. In this paper, we assess landscape fragmentation dynamics of six landscape units belonging to two European regions, i.e. Sardinia in Italy (from 2003 to 2008), and Andalusia in Spain (from 2005 to 2009). We developed on three indices: the Infrastructural Fragmentation Index (IFI), the Urban Fragmentation Index (UFI), and the Connectivity Index (CI). We found that coastal areas generally suffer from an higher pressure due to the demand of longer or faster transport infrastructures and new settlements and less fragmented areas tend to show the most relevant dynamics in a sort of convergent pattern. Even though landscape fragmentation and connectivity are intuitively complementary phenomena, in this paper we did not found any statistical evidence of this associative property.     

How air transport connects the world – A new metric of air connectivity and its evolution between 1990 and 2012

To understand as to how scheduled air services link a region to other markets, we develop connectivity and hub centrality metrics. These metrics measure the quality of all scheduled air services in terms of frequency, detours, layover time and destination quality using a valuation scale being derived from observed passenger behavior. By computing yearly scores for 1990 to 2012, we analyze the geography of and trends in worldwide connectivity and hub centrality. While we observe significant growth of aggregate connectivity, the trends are heterogeneous with regard to the type of connectivity as well as time and location.     

跨层次网络嵌入对发明者二元式创新的影响

发明者的创新活动同时嵌入在知识网络和社会网络中，从多层次网络视角出发，利用华为公司和苹果公司2002-2017年在美专利申请数据，就跨层次网络结构特征对发明者二元式创新的影响进行理论分析，并用负二项回归模型加以实证。结果表明：发明者的跨层凝聚性和跨层连通性均与二元式创新存在倒U型关系;发明者隶属点度加强了跨层凝聚性和跨层连通性与二元式创新之间的倒U型关系。结论弥补了当前单一层面的网络功能机制研究，对指导创新主体构建创新网络具有一定意义。