广西北部湾港口保税物流腹地经济圈构建研究

广西北部湾港口保税物流群的设立是我国为发展西部地带经济,推动中国-东盟自由贸易区而采取的重要举措。文章结合我国保税物流兴起的背景,介绍了广西北部湾港口保税物流业务分工内容及其对腹地经济区域的辐射作用,分析了广西北部湾港口保税物流腹地经济圈发展存在的问题,提出相应的发展思路和对策。     

Real-world gaseous and particle emissions of a Bi-fuel gasoline/CNG Euro 6 passenger car

The objective of the present study is the assessment of the environmental impact of a bivalent (bi-fuel) vehicle, running either on gasoline or compressed natural gas (CNG). To that aim, a Euro 6 passenger car was tested under various real-world driving conditions. In order to cover the full range of conventional powertrains currently in the market, the tests were also repeated on a Euro 6 diesel passenger car. Both cars were driven in two routes, the first complying with the regulation limits and the second going beyond them. Carbon monoxide (CO), nitrogen oxides (NO_x) and particle number (PN) emissions were recorded using a Portable Emissions Measurement System (PEMS). Apart from the aggregated emission levels, in g/km, the exact emission location along the route was also assessed. Natural gas proved beneficial for CO and PN emissions, the level of which always remained below the respective legislation limits. On the other hand, under the dynamic driving conditions with gasoline, the relevant limits were exceeded. Cold start, occurring at the beginning of the urban part, and motorway driving were identified as major contributors to total emissions, especially in gasoline mode. However, the application of natural gas was associated with a penalty in NO_x emissions, which were significantly increased as compared to gasoline. Local peaks within the urban part were identified in CNG mode. In any case, the diesel vehicle was by far the highest NO_x emitter.     

Cranes scheduling in frame bridges based automated container terminals

This paper investigates crane scheduling problems for a new type of automated container terminal system, which is based on multi-storey frame bridges. For the new design concept, this paper studies how to schedule two types of cranes, i.e., quay cranes and bridge cranes that transfer containers between different storeys. The schedules of these two types of cranes impact the operation efficiency of the terminal system. Mathematical models are proposed for the two scheduling problems. Meta-heuristics are developed to solve them. Numerical experiments are conducted to validate the effectiveness of the proposed models and the efficiency of the proposed solution method.     

Strategic responses to institutional forces pressuring sustainability practice adoption: Case-based evidence from inland port operations

This article investigates strategic responses of inland ports to institutional forces pressuring their adoption of sustainability practices. We postulate that even though inland port operators strive for economic viability, there are growing pressures from various stakeholders for continuous enhancement of their environmental and social sustainability practices. We apply institutional theory to classify the effects of these forces based on five institutional antecedents – cause, constituents, content, control, and context – and further expand our theoretical framework with resource dependence tenets to discuss the spectrum of strategic responses available to inland ports to deal with institutional forces. We examine our theoretical arguments with empirical evidence collected from four inland ports using a case study-based approach. We conclude that while inland ports have a strong disposition towards social sustainability, economic considerations are still most emphasized, and environmental issues are mostly regarded in compliance with the legally mandated minimum. The most important sources of institutional pressure are identified as cause, constituents, and control. In a further step, we present evidence of the inland ports’ potential strategic responses. The study also provides insights for managers and policy makers on strategic options as appropriate organizational responses to proliferating institutional pressures for sustainability practices adoption.     

The effect of institutional factors on public–private partnership success in ports

Port public–private partnerships (PPPs) are considered to be an important emerging mechanism for port development and improvement in port performance especially for developing countries. This paper empirically investigates the effect of institutional factors in the success of port’s PPPs; the latter defined as the attractiveness of the PPP project for private bidders and the market competitiveness of the facility. The empirical investigation of a large sample of ports finds that ‘regulatory quality’, ‘market openness’, ‘ease to start a business’ and ‘enforcing contracts’ are important institutional determinants of port PPP success and may ultimately contribute to port development and economic growth. The results are consistent with and add to the theoretical literature whereas practical implications for port authorities, managers and investors are discussed.     

大型沉箱在广州港南沙港区一期工程中的应用

介绍广州港南沙港区一期工程中所应用的大型沉箱及施工工艺。     

混合算法在港口吞吐量预测中的应用

文章利用主成分分析方法,提取出影响宿迁港口吞吐量的关键因子,在此基础上,提出了一种新的运量混合预测方法,即联合时间序列法和因果分析法;最后通过回归分析,给出了宿迁港口吞吐量与国内生产总值的关系,为宿迁港的发展和港口总体布置规划提供了一定的依据。     

基于CDMA无线信道的TCP 与UDP协议性能研究*

以吞吐率和有效因子为性能指标,分别就 i．i．d和相关无线信道模型对 TCP和 UDP协议进行了研究．虽然 UDP协议获得了TCP协议吞吐率性能的上界,但低时延、大拥塞控制窗口和信道相关性也有助于 TCP协议吞吐率逼近 UDP协议;对于有效因子性能,TCP协议性能更优．分析结果表明,拥塞控制窗口对于 TCP协议的有效因子和吞吐率2个性能指标的影响相互矛盾,因而窗口大小需要根据具体的应用进行取舍．     

港口企业开展物流金融业务的模式及意义

我国港口货物吞吐量和集装箱吞吐量已经连续多年居世界第一,但我国港口大而不强,还是以传统的仓储、搬运等物流活动为主,缺少增值服务,港口之间的竞争也越来越体现为其所在的供应链之间的竞争,因此发展融入港口供应链中的物流金融增值业务,是增强港口竞争力和盈利能力的重要途径.本文研究了物流金融概念,港口企业开展物流金融业务的模式及意义.     

进离港航班容量及其影响因素

针对机场容量限制导致的航班延误问题,以最大航班流量为决策目标,建立了进离港航班容量模型.该 模型采用离散时间混合排队算法,对可能出现的冲突情况建立转移概率矩阵,并基于冲突因子优化模型性能,推 导出进离港容量的数学公式,设计出算法流程.以成都双流国际机场的实际数据进行仿真,结果表明:当进、离港 航班率分别为0.6和0.5、机场吞吐率为0.8时,模型预测的数据与实际航班信息的标准差分别为1.552和 1.436;当进港请求近似为泊松分布时,机场吞吐率越大,拒绝的航班请求数量越少,机场吞吐率与计划进离港容 量正相关.