海面高对北斗定位精度影响的研究

研究了海面高要素对北斗一号卫星导航定位系统定位精度的影响规律,并进行了仿真计算,利用研制的海上用户接收机进行了陆地试验和海上试验,证明了考虑海面高因素的海上用户接收机能有效地提高北斗定位精度。     

基于大数据的复杂海运环境下船舶路径自动生成方法

随着全球经济的快速发展,海上运输由于其运力大、运费低而变得更具实用性。然而,这也意味着在海上航道行驶的船只正变得越来越多,这将导致在复杂的海洋环境中航海船只发生事故的可能性会很高。据相关历史的统计,在海域中航行缺乏高精度导航数据会导致大量事故,这种累积的事故信息可以被用来提高航海的安全性。本文通过将蕴含在AIS (Automatic Identification System) 大数据中的经验导航信息挖掘出来,以辅助实现复杂海事环境下安全可靠的船舶路径的生成。本文提出了一种基于大数据自动生成船舶路径的新方法。该方法首先在大量船舶轨迹上通过DBSCAN (Density-Based Spatial Clustering of Applications with Noise) 聚类形成不同的轨迹矢量簇。然后,迭代计算轨迹矢量簇的中心线,并从这些中心线之间的节点-弧段拓扑关系来构建航道网络。最后,基于航道网络来实现船舶路径的生成,对于航道网络未覆盖的海域,则通过海洋环境风险栅格的路径规划来实现船舶路径的生成。不同海域不同AIS数据集进行的多次实验结果表明,本文提出的船舶路径生成方法是有效性。     

灰度共生矩阵纹理特征对SAR海冰漂移监测的增强性能研究

海冰漂移监测对气候变化分析、船只航行、海上石油平台等海上活动安全作业具有重要意义。当前主流的SAR海冰漂移监测方法多是基于SAR灰度图开展的,其受噪声、环境等因素的影响较大,导致其在海冰漂移探测时,特征失配率高,匹配正确率低。针对这一问题,本文尝试利用SAR海冰纹理特征来增强海冰漂移探测性能。首先对比分析了8种纹理特征对海冰漂移探测中特征匹配的增强性能,筛选出能够有效增强特征匹配性能的最优纹理特征;其次进一步分析了海冰类型、入射角和分辨率对基于纹理特征的海冰漂移探测性能增强的影响。实验结果表明,均值是最优的纹理特征,与SAR强度图相比,特征匹配正确率提高了约7%。     

珠江口海事三维地理信息系统的研究与开发

通过对珠江口水域海事管理的需求分析,利用航天／航空影像,数字高程数据、海事电子地图数据,以及航政、助航等专题资料,研制开发珠江口水域三维形式的地理信息系统,实现查询、浏览、管理等功能,为海事管理提供方便直观的工作平台。     

船舶航行安全信息可视化关键技术研究

针对当前NAVTEX和EGC接收机无法实现船舶航行安全信息可视化的问题,提出一种基于电子海图显示与信息系统的船舶航行安全信息可视化方法,研究并解决涉及的若干关键技术。经实践应用表明,该方法可有效解决报文信息存在的效能低、标绘难、非图形化显示等弊端,同时可推动海岸电台进一步发展基于新型通信手段的海上安全信息播发业务。     

Squat prediction in muddy navigation areas

Common squat prediction formulae to assess the navigation safety usually do not take into account the bottom condition. Nevertheless, the presence of a fluid mud layer is not an uncommon condition in confined areas where accurate squat predictions are necessary. From 2001 to 2004 an extensive experimental research program was carried out to measure the manoeuvring behaviour of deep drafted vessels in muddy areas. A part of the program focused on the undulations of the water-mud interface and their relationship to the ship’s squat. Mostly the sinkage of the ship is damped due to the presence of the mud layer, but a larger trim can occur due to the water-mud interface undulations. This article presents a mathematical model to predict the squat in muddy navigation areas.     

福建省海洋非法采砂行为管控初探

天然海砂是一种海洋矿产资源,由于在城市建设中使用十分广泛,海砂成为仅次于石油天然气的海洋第二大矿产资源。但近年来由于大量无度开采海砂,对海洋生态环境、海上航行安全以及建筑物安全都造成极大的破坏和影响。对此,各地执法部门进行了一系列打击非法采挖海砂专项行动,虽取得一定成效,但违法采挖海砂的猖獗势头依然未能得到遏制。文章从目前海砂市场的供求现状以及非法采挖海砂造成的问题出发,对执法部门打击非法采挖海砂未能取得预期效果的原因进行分析,并提出合理规划海砂合法开采、加大非法采砂惩处力度、合力完善治砂长效机制、用现代信息技术助力采砂监管等4个方面的解决思路,规范海洋采砂行为,使市场需求和环境保护得到兼顾。     

国际标准电子海图显示平台的研制

随着我国数字海图产品不断的生产完善,研制自主知识产权的“电子海图显示与信息系统（ECDIS）”逐渐成为工作的重心,而这项任务的核心是符合S-57数据传输标准及S-52电子海图模式的显示平台的研制,以此为基础才能研制出我国自主知识产权的ECDIS。在研究电子海图国际标准化的基础上,通过大量的技术实践,实现了自主知识产权的国际标准电子海图显示平台,为我国建立自主知识产权的ECDIS打下了坚实的基础。     

The recreational use of beaches and consequences for the development of new trends in management: the case of the beaches of the Metropolitan Region of Barcelona (Catalonia, Spain)

This article offers some reflections on beach management, on the basis of the results of a survey on the recreational use of beaches and beach users' perception, which was carried out in the Metropolitan Region of Barcelona in 1992. The first part outlines the situation of the beaches, recent metropolitan beach policy and the organization of administrative bodies responsible for beach management. Survey objectives and methods are also explained briefly. In the second part, the principal results of the survey are presented and different beaches are compared in an attempt to analyse the types of users, the uses they make and the perception they have of the beaches. The conclusions identify new emerging social needs which demonstrate that new trends in beach management are also needed. Practical recommendations, related to this emerging perception of beaches as natural systems, are suggested.     

Relationships between safety culture aspects – A work process to enable interpretation

Knowledge about the existing safety culture in a maritime organization such as in shipping companies or on board ships can enable the formulation of effective interventions to maintain and improve safety culture and safety in the organization. When assessing the safety culture, questionnaires developed for this purpose are often used. This paper proposes a work process that facilitates the analysis and interpretation of the relationships between safety culture aspects using questionnaire data. The work process includes the use of variable cluster analysis where the cluster solutions are presented in dendrograms. These were found to be an excellent way to visualize complex relationships in the quantitative data and to facilitate the understanding of the safety culture concept. Results are presented from applying the statistical process to safety culture data from six Swedish ships in international traffic. The visualized safety culture results can enable group discussions about safety on different organizational levels and can constitute an important input to the continuous improvement processes for safety and safety culture.     

Safety culture,working conditions and personal injuries in Norwegian maritime transport

The aim of the study is to examine the influence of safety culture and working conditions on personal injuries and risk perception on vessels sailing along the coast of Norway (mostly bulk, well and general cargo). The study employs three methods: small-scale survey (N = 180) to crewmembers, reference group meeting and qualitative interviews with sector experts (N = 10). Results indicate that organisational safety culture, manning level on board, work pressure and demanding working conditions are closely related, and that these factors influence injuries and risk perception on the studied vessels. Analyses indicate that lower manning levels induce higher work pressure, which negatively influences safety culture. Respondents on vessels with lower manning levels (3–4 people) score lower on many of the key variables of the study: they experience more personal injuries, experience more stress, and rate the safety culture as lower than respondents on other vessels. It is not examined whether manning levels are too low. The safety challenges of vessels with lower manning levels are probably due to framework conditions (e.g. economy, competition). Future research should examine how to improve working conditions and safety culture on these vessels, given the current manning levels and framework conditions.     

The communicative competence of Chinese seafarers and their employability in the international maritime labour market

In the past two decades, the seafarer workforce in China has been growing at a much faster pace than that of the Chinese merchant fleet, resulting in an oversupply of seafarers in the domestic market. As one of the major seafarer suppliers in the world, China still faces great challenges to assign Chinese seafarers to the international maritime labour market. Although literature claims that a lack of English communication ability of Chinese seafarers is one of the main barriers for them to compete with seafarers of other nationalities for job opportunities, there is little empirical research to substantiate such claim. To fill this gap, this paper aims to investigate: 1) employers’ views on the current level of Chinese seafarers’ communicative competence; and 2) to what extent their communicative competence correlates with their employability in the international maritime labour market. To achieve the research objectives, a questionnaire survey relating to factors affecting the employability of Chinese seafarers on foreign ships was conducted. Interviews were carried out with employers who had been recruiting seafarers in China. The findings show that English communicative competence is among the top determinants for seafarers to be employed on foreign ships. Most employers believe that there has been a declining trend in the communicative competence of Chinese seafarers over the last decade. Employers interviewed agree that a high priority should be placed on the improvement of quality of maritime English teachers.     

基于可重置联邦滤波器的水下运载体导航定位方法

单一导航系统无法满足水下运载体高精度、高可靠性的导航需求,文中根据常用水下导航系统的特点,提出基于可重置联邦滤波器的水下运载体导航定位方案,设计了以惯导系统(INS)为主参考系统,声学定位系统/深度计、多普勒计程仪(DVL)、罗经为子参考系统的联邦滤波器,并进行了仿真研究。结果表明文中设计的滤波器能有效融合各个传感器的导航信息,实现水下运载体高精度导航定位,并具有一定容错性。     

Geodetic Datum of Indonesian Maritime Boundaries: Status and Problems

Indonesia has maritime boundaries with 10 countries namely: Australia, Timor Leste, Papua New Guinea (PNG), Palau, Philippines, Vietnam, Thailand, Malaysia, Singapore, and India. Many treaties have been ratified concerning these boundaries. Unfortunately, many coordinates of boundary points mentioned in the treaties are not clear in relation to their geodetic datum. The uncertainty in geodetic datum of boundary points introduces complications and problems in spatial management of Indonesia's maritime boundaries, since it can displace the boundary lines from their assumed true location. This study investigates the possible original geodetic datums for the maritime boundaries between Indonesia and neighboring countries, in the case they are not explicitly stated in the treaties. The displacements of boundaries in WGS84 datum are generally in the order of a few hundred meters, i.e., about 200 to 400 m, depending on the assumed original geodetic datum being considered. These boundary displacements are spatially advantageous for Indonesia in some cases and also disadvantageous in others. The study will sum up with some conclusions and recommendations.     

The effectiveness of the ISM Code: A qualitative enquiry

Studies conducted to determine the efficacy of the ISM Code in the past include investigations of the trends of accident numbers and insurance claims and users' perceptions. None of these, however, could produce a definitive conclusion. This is because both the use of safety outcome as well as the use of perception have inherent problems and are not reliable. This paper takes a different approach. It draws on wider research on management of workplace health and safety to ascertain whether or not employment and social conditions that support effective implementation of self-regulation are present in the maritime context. The findings reveal a considerable disparity between managers' and seafarers' understanding of the use of the Code resulting in a wide gap between its intended purpose and practice. The analysis shows that the critical factor is the lack of seafarers' participation in management of workplace health and safety. The underlying causal factors for such lack of participation were located in seafarers' poor employment condition and low-trust relationship with their managers.     

基于动态海洋环境要素的航行风险评估方法研究

海洋气象环境复杂多变,船舶航行风险随时间演变具有较高的不确定性.本文从时空分析的角度出发,动态评估船舶的航行风险:选择风场、海流、海浪、海温等4种动态因素和海雾发生频率、海底地形等2种静态因素作为评估因子,使用层次分析法(analytic hierarchy process,AHP)计算各评估因子的权重,在此基础上,利...     

Digital selective calling and direct printing techniques in the mobile maritime service

For a variety of reasons, communications with ships on the high seas have significantly lagged behind other communications services. For example, the maritime mobile service is practically the only service where manual Morse still constitutes a major part of the communications services. In the last few years, however, some new techniques have been developed which promise to improve maritime communications. This paper provides a background discussion of maritime mobile communications and describes two recent techniques, digital selective calling and direct printing in some detail, together with their impact on maritime communications and safety at sea. Finally, the status of and procedures for international acceptance and standardization are discussed, and national efforts to promote acceptance of these techniques are described.     

The US freedom of navigation program preserving the law of the sea

The 1982 United Nations Convention on the Law of the Sea prescribed extensive rules of behavior for the international community in the oceanic regime. Some of the most important provisions of the Convention are those regarding the freedom of navigation and overflight in various maritime zones, i.e. territorial seas, international straits, archipelagos, exclusive economic zones and the high seas.While most coastal nations are complying with the navigation and overflight provisos of the Convention, some are not. Where excessive maritime claims exist, the US has evolved an ambitious Freedom of Navigation (FON) Program which challenges these excessive claims. This Program was initiated under the Carter Administration in 1979 and has continued, unabated, ever since.As the international community prepares for the day when the 1982 Convention becomes universally-recognized international law, there are likely to be periodic excessive maritime claims. In cases where the Convention's dispute settlement provisos fail to resolve excessive claims, the community of nations may find it useful to use the US FON Program as an example for the enforcement of maritime rules.