数字服务贸易已成为拉动各国贸易增长和经济发展的新引擎,在“一带一路”倡议下,沿线国家数字服务贸易开展日益紧密,贸易环境不确定性也在增加,研究“一带一路”沿线国家数字服务贸易网络韧性对保障各国数字贸易发展具有深远意义。本文...数字服务贸易已成为拉动各国贸易增长和经济发展的新引擎,在“一带一路”倡议下,沿线国家数字服务贸易开展日益紧密,贸易环境不确定性也在增加,研究“一带一路”沿线国家数字服务贸易网络韧性对保障各国数字贸易发展具有深远意义。本文考察六类数字服务贸易产业,采用中断模拟方法,通过比较“一带一路”沿线国家和全球数字服务贸易网络情况,从静态和动态两方面综合分析“一带一路”沿线国家数字服务贸易网络的韧性表现。结果表明:1) 六类数字服务贸易网络的平均路径长度普遍较短,平均聚类系数较高,网络层级性明显;2) 电子信息和其他商业服务网络呈现异配性特征,表现出一定的韧性水平;3) 相较随机攻击,蓄意攻击下数字服务贸易网络性能下降速率更快且综合韧性水平更低;4) 综合四种中断情况,其他商业服务贸易网络韧性水平最高,电信、计算机和通讯贸易网络知识产权使用贸易网络韧性较高,保险养老金服务和金融贸易网络韧性水平较低,个人、娱乐和文化网络总体韧性水平最低。Digital trade has become an emerging and important form of global trade. Under the “Belt and Road” initiative, the digital service trade of countries along the Belt and Road has become increasingly close, and the uncertainty of the trade environment is also increasing. Studying the resilience of digital service trade network of countries along the “Belt and Road” has far-reaching significance for ensuring the development of digital trade of various countries. This paper examines six types of digital service trade industries, adopts the interruption simulation method, and comprehensively analyzes the resilience of the digital service trade networks of the countries along the “Belt and Road” from both static and dynamic aspects by comparing the situation of the countries along the “Belt and Road” and the global digital service trade networks. The results show that: 1) The average path length of the six types of digital service trade networks is generally short, the average clustering coefficient is high, and the network hierarchy is obvious;2) Electronic information and other commercial service networks have heterogamous characteristics, showing a certain level of resilience;3) Compared with random attacks, the performance decline rate of digital service trade network under deliberate attacks is faster and the comprehensive resilience level is lower;4) Combining the four disruption scenarios, other business service trade networks have the highest resilience, telecommunications, computer and communication trade networks have the higher resilience, insurance and pension services and financial trade networks have the lower resilience, and personal, entertainment and cultural networks have the lowest resilience.展开更多
This paper provides an analytical framework for the outage probability evaluation of dual-hop decode-and-forward relay systems operating over K-μfading channels in the presence of co-channel interference. The interfe...This paper provides an analytical framework for the outage probability evaluation of dual-hop decode-and-forward relay systems operating over K-μfading channels in the presence of co-channel interference. The interferers are independent non-identically distributed K-μfading. An accurate analytical-form expression for the cumulative distribution function of the received signal power to interference and noise ratio is derived. Various numerical results are compared with Monte Carlo simulation results in order to corroborate the accuracy of the proposed expressions. Our results show that increasing the value of kappa of main links will decrease the outage probability of relay systems. Furthermore, the system performance degrades with the number of interferences.展开更多
Downtime due to adverse wave conditions for vessels at berth is an important commercial aspect in the planning and development of a sea port or a berthing terminal. This paper describes a practical technique for preli...Downtime due to adverse wave conditions for vessels at berth is an important commercial aspect in the planning and development of a sea port or a berthing terminal. This paper describes a practical technique for preliminary assessment of operational downtime at a proposed bulk terminal. Time-series wind and wave data at an offshore location was purchased. Numerical modelling was then carried out using the MIKE21 SW （spectral wave） model developed by DHI （Deutsches Hydrographisches Institut） to transform these offshore waves into inshore in order to derive wave conditions at the berth. Both wind-waves and swell-waves were considered. Waves affecting the head and beam of a vessel were considered separately for a wide range of vessel sizes with DT （displacement tonnage） ranging from 5,000 tons to 〉 200,000 tons. The limiting wave height H5% was used. Operational downtime was also calculated using significant wave height, Hs as a criterion with limits ofHs = 1.0 m for beam seas and Hs = 1.5 m for head seas. The methodology and lessons learnt from the study can be applied for the development of any sea port worldwide.展开更多
文摘数字服务贸易已成为拉动各国贸易增长和经济发展的新引擎,在“一带一路”倡议下,沿线国家数字服务贸易开展日益紧密,贸易环境不确定性也在增加,研究“一带一路”沿线国家数字服务贸易网络韧性对保障各国数字贸易发展具有深远意义。本文考察六类数字服务贸易产业,采用中断模拟方法,通过比较“一带一路”沿线国家和全球数字服务贸易网络情况,从静态和动态两方面综合分析“一带一路”沿线国家数字服务贸易网络的韧性表现。结果表明:1) 六类数字服务贸易网络的平均路径长度普遍较短,平均聚类系数较高,网络层级性明显;2) 电子信息和其他商业服务网络呈现异配性特征,表现出一定的韧性水平;3) 相较随机攻击,蓄意攻击下数字服务贸易网络性能下降速率更快且综合韧性水平更低;4) 综合四种中断情况,其他商业服务贸易网络韧性水平最高,电信、计算机和通讯贸易网络知识产权使用贸易网络韧性较高,保险养老金服务和金融贸易网络韧性水平较低,个人、娱乐和文化网络总体韧性水平最低。Digital trade has become an emerging and important form of global trade. Under the “Belt and Road” initiative, the digital service trade of countries along the Belt and Road has become increasingly close, and the uncertainty of the trade environment is also increasing. Studying the resilience of digital service trade network of countries along the “Belt and Road” has far-reaching significance for ensuring the development of digital trade of various countries. This paper examines six types of digital service trade industries, adopts the interruption simulation method, and comprehensively analyzes the resilience of the digital service trade networks of the countries along the “Belt and Road” from both static and dynamic aspects by comparing the situation of the countries along the “Belt and Road” and the global digital service trade networks. The results show that: 1) The average path length of the six types of digital service trade networks is generally short, the average clustering coefficient is high, and the network hierarchy is obvious;2) Electronic information and other commercial service networks have heterogamous characteristics, showing a certain level of resilience;3) Compared with random attacks, the performance decline rate of digital service trade network under deliberate attacks is faster and the comprehensive resilience level is lower;4) Combining the four disruption scenarios, other business service trade networks have the highest resilience, telecommunications, computer and communication trade networks have the higher resilience, insurance and pension services and financial trade networks have the lower resilience, and personal, entertainment and cultural networks have the lowest resilience.
基金supported by the NSFC project under grant No.61101237the Fundamental Research Funds for the Central Universities No.2014JBZ001
文摘This paper provides an analytical framework for the outage probability evaluation of dual-hop decode-and-forward relay systems operating over K-μfading channels in the presence of co-channel interference. The interferers are independent non-identically distributed K-μfading. An accurate analytical-form expression for the cumulative distribution function of the received signal power to interference and noise ratio is derived. Various numerical results are compared with Monte Carlo simulation results in order to corroborate the accuracy of the proposed expressions. Our results show that increasing the value of kappa of main links will decrease the outage probability of relay systems. Furthermore, the system performance degrades with the number of interferences.
文摘Downtime due to adverse wave conditions for vessels at berth is an important commercial aspect in the planning and development of a sea port or a berthing terminal. This paper describes a practical technique for preliminary assessment of operational downtime at a proposed bulk terminal. Time-series wind and wave data at an offshore location was purchased. Numerical modelling was then carried out using the MIKE21 SW （spectral wave） model developed by DHI （Deutsches Hydrographisches Institut） to transform these offshore waves into inshore in order to derive wave conditions at the berth. Both wind-waves and swell-waves were considered. Waves affecting the head and beam of a vessel were considered separately for a wide range of vessel sizes with DT （displacement tonnage） ranging from 5,000 tons to 〉 200,000 tons. The limiting wave height H5% was used. Operational downtime was also calculated using significant wave height, Hs as a criterion with limits ofHs = 1.0 m for beam seas and Hs = 1.5 m for head seas. The methodology and lessons learnt from the study can be applied for the development of any sea port worldwide.
