浙江舟山金塘大桥施工期间通航问题初探

针对金塘大桥所处的特定环境,重点分析了拟建工程附近水域通航现状及船舶交通流量,在初步了解桥区附近水域影响通航的不利因素的基础上,提出几条通航方案供各方参考,并指出对于施工期间通航问题有待深入研究。     

我国船舶油污损害赔偿法律制度构想

随着船舶油污损害的加剧,我国正酝酿制订船舶油污损害赔偿专门立法。本文提出我国船舶油污损害赔偿立法应由四大基本制度构成,即适用范围制度、赔偿主体制度、赔偿范围制度、赔偿限制制度。     

Simulation optimization of the berth allocation in a container terminal with flexible vessel priority management

ABSTRACT

Solving the berth allocation problem (BAP) in ports is not trivial where the berth resources are limited and various sizes of vessels arrive with dramatically dissimilar loads. Especially in real scenarios, arriving vessels are accepted for a berth with the first come first served (FCFS) priority rule. This study proposes a decision support system coupled with a simulation optimization module based on the swarm-based Artificial Bee Colony optimization algorithm for solving the BAP. The proposed methodology was implemented for the Izmir port in Turkey. To investigate the influences of the vessel priorities on the BAP, four different experimental scenarios based on the single (SQM) and multiple queue models (MQM) were coupled with FCFS and proposed hybrid queue priority (HQP) rule. The results indicated that SQM scenarios were superior to MQM scenarios in a manner of minimizing the average vessel waiting times and the implementation of a dynamic berth allocation strategy for the MQM significantly decreases the vessel waiting times. Results of the SQM also imply that utilization of the HQP approach further minimizes the average vessel waiting times and increases the berth utilization and port throughput without yielding excessive waiting times for the larger vessels compared with the FCFS priority rule.     

Road traffic conditions in Kenya: Exploring the policies and traffic cultures from unstructured user-generated data using NLP

Road traffic accidents (RTA) are a prevalent cause of fatality with African countries having the highest fatality index (25–34 per quota). The World Health Organization estimates Kenya's fatality rate due to RTA at 28 per quota. From literature, the country's fatality and injuries have increased by 26% and 46.5%, respectively, since the year 2015. The country is faced with incomplete RTA data capturing, hindering effective planning and policy adjustments to curb the menace. In this paper, we scrapped user-generated data (Twitter) and national transport and safety authority's (NTSA) reports to shed light on traffic safety, practices, and cultures in the country. To this end, we gathered 1,000,000 tweets and 8000 speeding entries between 2015 and 2021 and performed natural language processing (NLP) and quantitative study of the data. We applied NLP and n-gram search of keywords to categorize data into 8 topics: traffic, public service vehicle (PSVs), policing, accident, infrastructure, recklessness, robbery, and corruption. From the data, policing, which touches on all police and law-enforcement-related activity was found to be highly correlated with PSVs, recklessness, accidents, traffic congestion, robbery, infrastructure, and corruption with indices of r(76) = 0.92, 0. 91, 0.87, 0.82, 0.81, 0.76, and 0.70, respectively with p < 0.001. The topic modeling confirmed the identified topics to be the latent discussion issues affecting the public. From the study, PSVs, policing and traffic flow were isolated as key issues that ought to be addressed immediately. The research recommended the integration of driver monitoring systems to strengthen policing. The research, which utilized unstructured data, points to the utility of data mining which would greatly benefit traffic research, particularly African-based studies, that suffer from data inadequacy.     

Distributed model predictive control for vessel train formations of cooperative multi-vessel systems

Recently, the cooperative control of multiple vessels has been gaining increasing attention because of the potential robustness, reliability and efficiency of multi-agent systems. In this paper, we propose the concept of Cooperative Multi-Vessel Systems (CMVSs) consisting of multiple coordinated autonomous vessels. We in particular focus on the so-called Vessel Train Formation (VTF) problem. The VTF problem considers not only cooperative collision avoidance, but also grouping of vessels. An MPC-based approach is proposed for addressing the VTF problem. A centralized and a distributed formulation based on the Alternating Direction of Multipliers Method (ADMM) are investigated. The distributed formulation adopts a single-layer serial iterative architecture, which gains the benefits of reduced communication requirements and robustness against failures. The impacts of information updating sequences and responsibility parameters are discussed. We furthermore analyze the scalability of the proposed method. Simulation experiments of a CMVS navigating from different terminals in the Port of Rotterdam to inland waterways are carried out to illustrate the effectiveness of our method. The proposed method successfully steers the vessels from different origins to form a vessel train. Due to the effective communication, vessels can timely respond to the velocity changes that others make. After the formation is formed, the distances between vessels become constant. The results show the potential to use CMVSs for inland shipping with enhanced safety.     

Expert versus lay perception of the risks of motor vehicle-generated air pollution

We explore whether experts’ perceptions of risk differ systematically from those of the public. To do so, we examine whether experts and non-experts make different location decisions in response to ground-level ozone pollution, one of the byproducts of motorized transportation. Physicians are experts in the field of health, and thus may differ from their lay neighbors in their knowledge of and attitude toward pollution and its health risks. If so, it is possible that they value locations with cleaner air differently than their neighbors do. Here we use hedonic price models based on willingness to bear housing and commute burdens to examine the differential valuation of clean air by doctors and laypeople in the Los Angeles region between 1980 and 2000. We find no evidence that doctors are more or less more willing than comparable lay residents to trade off time or money to live in cleaner-air neighborhoods.     

简支变连续桥梁的设计应用分析

简支变连续桥梁的受力比较复杂,应从结构型式、断面尺寸、纵横向布置、预应力束布置、抗裂验算、挠度验算等方面对具体实例进行分析,以更好地指导工程实践。     

基于集成仿真的灯光渔船艏部型线优化

针对我国现有渔船标准化建设中遇到的船体型线优化难的问题,提出一种基于集成仿真优化技术的船体型线优化方法,并以一艘灯光渔船的兴波阻力性能优化为例,通过半参数化方法提取10个控制参数用于艏部型线的变换,兴波阻力采用势流理论方法进行评估,并采用Sobol算法与梯度搜索算法相结合的优化算法。基于上述的船体型线优化方法最终得到兴波阻力性能最优的船型,优化结果表明,文中提出的船体优化技术是有效的,有助于加快推进渔船船型的标准化建设。     

关于《国际信号规则》增补船舶防污码语的建议

船舶发生污染事故时信息交流存在困难,建议增补船舶防污用语的码语,提供标准用语,解决语言隔阂。     

绞股蓝总皂甙抗心肌缺血作用的研究

用大鼠和家兔结扎冠脉法和乳鼠培养心肌细胞法,研究了绞股蓝总皂甙(GP)对心肌缺血的影响,结果表明GP对心肌缺血具有保护作用;按照Selye法制备大鼠心肌缺血/再灌心律失常,观察GP的影响。结果表明GP对心肌缺血/再灌心律失常具有对抗作用。