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1 – 10 of 903Zhizhou Wu, Yiming Zhang, Guishan Tan and Jia Hu
Traffic density is one of the most important parameters to consider in the traffic operation field. Owing to limited data sources, traditional methods cannot extract traffic…
Abstract
Purpose
Traffic density is one of the most important parameters to consider in the traffic operation field. Owing to limited data sources, traditional methods cannot extract traffic density directly. In the vehicular ad hoc network (VANET) environment, the vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) interaction technologies create better conditions for collecting the whole time-space and refined traffic data, which provides a new approach to solving this problem.
Design/methodology/approach
On that basis, a real-time traffic density extraction method has been proposed, including lane density, segment density and network density. Meanwhile, using SUMO and OMNet++ as traffic simulator and network simulator, respectively, the Veins framework as middleware and the two-way coupling VANET simulation platform was constructed.
Findings
Based on the simulation platform, a simulated intersection in Shanghai was developed to investigate the adaptability of the model.
Originality/value
Most research studies use separate simulation methods, importing trace data obtained by using from the simulation software to the communication simulation software. In this paper, the tight coupling simulation method is applied. Using real-time data and history data, the research focuses on the establishment and validation of the traffic density extraction model.
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Byung-Gak Son, Sangho Chae and Canan Kocabasoglu-Hillmer
Catastrophic supply chain disruptions can significantly damage the operational and financial performance of firms. While a growing body of literature on supply network structures…
Abstract
Purpose
Catastrophic supply chain disruptions can significantly damage the operational and financial performance of firms. While a growing body of literature on supply network structures has studied what influences supply networks' vulnerability to supply chain disruptions and capability to recover from them, it remains unclear how supply network structures change after major supply chain disruptions. We aim to provide an understanding of how these changes occur.
Design/methodology/approach
Using a natural experiment approach and supply network data from Factset, this study investigates how firms' supply network structures change after experiencing the catastrophic supply chain disruptions caused by the 2011 Tohoku earthquake and tsunami in Japan. We capture post-earthquake supply network changes using the measures of degree centrality and ego network density.
Findings
The results of the analysis suggest that compared to unaffected firms, the affected firms experience changes in their supply network structures tending toward lower complexity measured by in-degree centrality, out-degree centrality and ego network density.
Originality/value
This study contributes to social network theory and the complex adaptive supply network literature by providing empirical evidence of structural changes in supply networks after catastrophic supply chain disruptions. A managerial contribution is made by providing a reflection on why these changes might be occurring and alert firms to the challenges of managing complexity in their supply networks.
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This study aims to better inform environmental management at universities by applying and validating the policy integration processes theory through a case study of Manchester…
Abstract
Purpose
This study aims to better inform environmental management at universities by applying and validating the policy integration processes theory through a case study of Manchester Metropolitan University.
Design/methodology/approach
Social network analyses were used to identify, differentiate and categorise working networks of individuals and departments and the interconnections between them.
Findings
In an organisation, networks can be developed and active at departmental level but not at individual level. High numbers of departments can be doing work related to sustainable development whilst having low and medium levels of interconnections between departments. Influence of stakeholders throughout the network suggests levels of sustainable development policy integration at individual and departmental.
Practical implications
New insights provide evidence for universities’ environmental managers of the need of developing and implementing strategies that involve individuals’ work between departments by providing incentives, supporting capacity building and staff empowerment.
Originality/value
This paper applied and validated the theory of policy integration processes, showing that work at individual level and between departments needs more attention.
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Lianhua Liu, Aili Xie and Shiqi Lyu
This paper aims to clarify the spatial connection characteristics and organization mode of logistics economy of 21 cities in Guangdong Province under the background of the…
Abstract
Purpose
This paper aims to clarify the spatial connection characteristics and organization mode of logistics economy of 21 cities in Guangdong Province under the background of the integrated development of Guangdong, Hong Kong and Macao Bay area, and explore the spatial development characteristics and influencing factors of logistics economy in Guangdong Province.
Design/methodology/approach
This paper constructs the development level model of urban logistics economy in Guangdong Province from three aspects: demand level, supply level and support level, and uses the entropy weight method to measure the development level index of urban logistics economy in Guangdong Province. Then, the traffic accessibility index model is used to measure the traffic accessibility index between cities in Guangdong Province. Finally, using the social network analysis method, combined with the development level index of urban logistics economy in Guangdong Province and the urban traffic access index in Guangdong Province, this paper analyzes the spatial connection characteristics and influencing factors of logistics economy network in Guangdong Province.
Findings
There are regional differences in the development level of logistics economy in Guangdong Province; The overall network density of its logistics economic connection is large, but there is an imbalance in the network structure, and the core edge phenomenon is obvious; Logistics economic space presents the characteristics of double core development.
Research limitations/implications
Because the research object is the spatial connection characteristics of logistics economy in Guangdong Province, the research results may lack universality. Therefore, researchers are encouraged to put forward further tests.
Practical implications
By studying the spatial connection mode of logistics economy in 21 cities in Guangdong Province, China, this paper promotes the original methods and empirical contributions, and constructs the research framework of spatial relationship of logistics economy. This research framework is universal to a certain extent.
Social implications
This paper is conducive to promoting the integrated development of logistics economy in Guangdong Province and improving the balance of regional development of logistics economy.
Originality/value
Firstly, this study provides a new perspective to understand the spatial relationship and spatial spillover of logistics economy from relational data rather than attribute data. Secondly, This study enriched and broadened the research topic of spatial correlation of logistics economy. Thirdly, this research aims to promote the original methods and empirical contributions. Specifically, this study establishes a comprehensive research framework on the spatial network structure of logistics economy.
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As intermodal logistics networks play a crucial role in enhancing the entire logistics performance, effectively managing the intermodal logistics network has become a significant…
Abstract
As intermodal logistics networks play a crucial role in enhancing the entire logistics performance, effectively managing the intermodal logistics network has become a significant strategic consideration in international logistics. The existing literature stresses that inter-organizational knowledge exchange is essential to successfully integrating logistics components and for maximizing logistics performance in the long run. These contentions ensure that knowledge exchange between intermodal logistics network entities-such as shipping lines, port terminal operators, freight forwarders, road and rail freight operators and other related logistics operators-are key factors in facilitating the successful integration of an intermodal logistics network because an intermodal logistics network is an integrated part of the entire international logistics system. This paper aims to investigate the question of how intermodal logistics network entities can successfully exchange knowledge with each other, and whether the knowledge exchange can contribute to the effective integration of the intermodal logistics network. For this, this paper adopts the social network embeddedness perspective in order to identify a useful inter-organizational relationship mechanism within the intermodal logistics networks, allowing the facilitation of knowledge exchange among the network players. A conceptual framework will be developed for the exploration of the aforementioned relationships between the social network mechanisms, i.e. network density, tie strength, knowledge exchange among network entities, and intermodal logistics network integration. Following the parameters of this framework, the theoretical and practical implications will be discussed.
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Rafael Ventura, María J. Quero and Sofía Louise Martínez-Martínez
Linkages play a strategic role in improving actor disposition and resource density in university–industry ecosystems. Due to the importance of interconnected ecosystems for the…
Abstract
Purpose
Linkages play a strategic role in improving actor disposition and resource density in university–industry ecosystems. Due to the importance of interconnected ecosystems for the development of engaged universities, applying the service-dominant logic (SDL) perspective, the authors aim at developing theory on linkages that lead to a higher level of actor commitment and in turn result in increased actor disposition and greater resource density.
Design/methodology/approach
Data from semistructured interviews from four in depth case studies, known internationally as successful cases of university linkages development (Columbia Lab-to-Market Accelerator Network, Oxford University Innovation, Auckland Uniservices and the Münster Center for Interdisciplinarity), undergo qualitative analysis according to the Gioia methodology.
Findings
The results represent a contribution to the theory, as they highlight the strategic role of linkages in improving actor disposition and increasing resource density. Due to its shown importance, linkage is an element to be considered on its own in the innovation ecosystems configurations in the context of universities.
Practical implications
The results of the research have implications for university management, since they focus on how resources are mobilized and linked. The interactive roles of actors in ecosystems imply that the locus of value creation moves beyond the borders of the organization toward the linkages. Strategies for managing university–industry linkages (UIL) are presented.
Originality/value
To date there has not been sufficient theoretical or empirical contribution in the university–industry ecosystem context about the role of linkages to improve resource density through increased actor disposition.
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Muhammad Saadullah, Zhipeng Zhang and Hao Hu
The expected benefits of newly developed transportation infrastructures are the saving of travel time and further promoted transport economics. There is a need for a methodology…
Abstract
Purpose
The expected benefits of newly developed transportation infrastructures are the saving of travel time and further promoted transport economics. There is a need for a methodology of travel time estimation with acceptable robustness and practicability. Macroscopic fundamental diagram (MFD) represents the overall traffic performance at a network level by linking average flow, speed and density. MFD can be used to estimate network state and to describe various traffic management strategies. This study aims to describe the effect of new infrastructure development on the network performance using the MFD framework.
Design/methodology/approach
The scenarios of Islamabad Road network before and after the infrastructure construction were simulated, in which the floating car data set (FCD) for multiple modes was extracted. MFD has been formed for the whole region and partitioned region, which was divided on the basis of infrastructural changes. Moreover, this study has been extended to calculate travel time for multiple modes using the MFD results and the Bureau of Public Roads (BPR) function at a neighborhood level.
Findings
MFD results for the whole network showed that the speed of traffic improves after the construction of new infrastructure. The travel time estimates using MFD results were dependent on the speed estimates, whereas the estimates obtained using the BPR function were found to be dependent on the traffic volume variation during different intervals of the day. By using the FCD for multiple modes, travel time estimates for multiple modes were obtained. The BPR function method was found valid for estimating travel time of traffic stream only.
Originality/value
This paper innovatively investigates the change in network performance for pre-construction and post-construction scenarios using the MFD framework. In practice, the approach presented can be used by transportation agencies to evaluate the effect of different traffic management strategies and infrastructural changes.
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Maneerat Kanrak, Hong Oanh Nguyen and Yuquan Du
This paper presents a critical review of the economic network analysis methods and their applications to maritime transport. A network can be presented in terms of its structure…
Abstract
This paper presents a critical review of the economic network analysis methods and their applications to maritime transport. A network can be presented in terms of its structure, topology, characteristics as well as the connectivity with different measures such as density, degree distribution, centrality (degree, betweenness, closeness, eigenvector and strength), clustering coefficient, average shortest path length and assortative. Various models such as the random graph model, block model, and ERGM can be used to analyse and explore the formation of a network and interaction between nodes. The review of the existing theories and models has found that, while these models are rather computationally intensive, they are based on some rather restrictive assumption on network formation and relationship between ports in the network at the local and global levels that require further investigation. Based on the review, a conceptual framework for maritime transport network research is developed, and the applications for future research are also discussed.
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Maneerat Kanrak, Hong Oanh Nguyen and Yuquan Du
This paper presents a critical review of the economic network analysis methods and their applications to maritime transport. A network can be presented in terms of its structure…
Abstract
This paper presents a critical review of the economic network analysis methods and their applications to maritime transport. A network can be presented in terms of its structure, topology, characteristics as well as the connectivity with different measures such as density, degree distribution, centrality (degree, betweenness, closeness, eigenvector and strength), clustering coefficient, average shortest path length and assortative. Various models such as the random graph model, block model, and ERGM can be used to analyse and explore the formation of a network and interaction between nodes. The review of the existing theories and models has found that, while these models are rather computationally intensive, they are based on some rather restrictive assumption on network formation and relationship between ports in the network at the local and global levels that require further investigation. Based on the review, a conceptual framework for maritime transport network research is developed, and the applications for future research are also discussed.
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This paper examines the relationship between transport connectivity and regional economic development in China. It develops measurements appropriate for transport connectivity…
Abstract
This paper examines the relationship between transport connectivity and regional economic development in China. It develops measurements appropriate for transport connectivity based on a set of evaluation models. This model is used to analyze the logistic connectivity of China’s 31 provinces by focusing on 11 variables, including some new factors (Density of road network, Density of railway network, Number of Internet Users) not used in previous studies, over the 13-year period from 2002 to 2014. Using panel data regression analysis, the empirical results show a statistically significant and positive impact of transport connectivity (factors like Density of road network, Density of railway network and Number of Internet Users) on economic development in China. In particular, the Number of internet users is a key factor reflecting information connectivity in all the variables. Comparative analysis regarding economic development is conducted to benchmark between coastal provinces and interior provinces. Like most previous research, this study yields the same finding of higher impact of transport connectivity on economic development in eastern provinces than in western provinces. This study suggests that decentralized decision-making will be significantly more efficient for analyzing regional infrastructure development. It also shows that the influence of transport connectivity on economic development is dependent on a certain developmental stage. This suggests that an economic region should adopt different development strategies for transport connectivity during different stages of development.
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