基于消息机制的MicroCAN协议开发与应用

设计了针对小型系统的MicroCAN总线协议．该协议规范了消息机制，实现数据传输单帧与多帧接口的统一，保障数据传输的可靠性；规范了大数据量传输机制，利用打包与解包技术，保障数据传输的正确性与高效性．详细阐述了协议的实现方法．该协议已成功应用于调距桨连续数据记录仪中，测试结果表明该协议具有高可靠性和高效性的特点．     

AIS中四种协议的应用探讨

此文对AIS工作过程中所使用的四种协议进行了探讨，主要包括各种协议的含义及使用的场合，相关协议的重要参数及其作用，以及AIS的工作流程中各种协议的衔接并发挥其作用等作了阐述。     

一种改进的FAMAC协议的仿真与性能分析

介绍了一种多信道接入协议MC，提出了一种基于虚拟载波监听的改进方案，利用OPNET软件对其性能进行了分析，仿真结果表明改进的FAMAC协议与原FAMAC协议相比，在含有隐藏终端和暴露终端的复杂网络拓扑条件下能够显著地节约信道资源，而协议的性能却没有明显的下降。     

Ad Hoc网络路由协议性能研究

文章对AdHoe网络中的三种路由协议（DSDV、AODV和DSR）进行了分析和比较，并通过NS-2仿真软件，对三种协议进行了仿真。通过分组传递交率、端到端延迟和路由负载等指标，对协议在不同环境下的性能进行了分析和比较，并详细讨论了仿真结果。结果显示，AODV和DSR协议的总体性能要优于DSDV协议，而AODV和DSR则各有优缺点，分别适用于不同的应用环境。     

基于CSMA／CA的无线自组网MAC协议性能分析

针对无线自组网络中存在的隐藏、暴露终端问题，提出了一种基于CSMA／CA协议改进的无线自组网MAC层协议，在CSMA／CA协议的基础上增加RTS／CTS握手信号，提高了网络的性能。同时，文章通过理论分析和仿真结果两种方式对基本的CSMA／CA与带RTS／CTS的CSMA／CA协议在多跳无线自组网下的吞吐量和时延进行了比较分析，证明了改进后的协议的优势。     

一次没有结束的成功会议——解读哥本哈根气候变化大会

经过13天的艰苦谈判，哥本哈根气候变化大会终于达成了《哥本哈根协议》，于12月19日落下帷幕。尽管这份不具有法律约束力的协议低于外界的预期，但是这毕竟是一份值得称颂的协议。这份协议是在各方共同努力下，锁定共识，传承成果，明确方向，维护了全球应对气候变化大局和坚持“共同但有区别的责任”原则，     

NMEA2000协议解析及其在船舶导航系统中的应用

CAN现场总线是NMEA2000协议的基础，对船载电子设备网络系统的构建起到关键作用。对NMEA2000协议进行了解析，描述了协议功能及分层结构。在船舶导航系统中，应用NMEA2000协议的消息参数群对导航信息数据进行组织与传输，是实现船舶集成管理的解决方法。     

一种适于Ad Hoc网的改进型TDMA协议

多址接入协议是影响Ad Hoc网络服务质量（QoS）的关键因素。针对特定用户关切的网络吞吐量、实时性、丢包率等参数指标，提出了一种固定分配机制和自适应竞争机制相结合的改进型TDMA协议（DTDMA）。首先介绍了胁TDMA算法以及工作流程，其次，分析了D-TDMA协议对网络吞吐量、业务实时性、丢包率的影响，最后，通过计算机仿真，验证了D-TDMA协议的正确性。     

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交通运输部海事局：关注船舶清污协议制度执行情况 为了解船舶清污协议制度实施过程中航运企业所遇到的问题，2月22日，交通运输部海事局就船舶污染清除协议制度的执行情况在沪进行了调研，     

OPC Server在桥机RCMS开发中的应用

在构建港口设备远程计算机管理系统（RCMS，Remote Computer Management System）时，考虑到ABB AC410PLC的通讯协议不是国际标准协议，协议细节未公开，给数据采集带来了困难，在分析了AC410与本地上位机的工作机制及数据结构后．提出了利用OPC Server构建与AC410的通讯方式。实践证明了该通讯方式的可行性。     

Vibration-assisted decommissioning of a slip joint: Application to an offshore wind turbine

An alternative option to the traditional grouted joint for wind turbines is a direct steel-to-steel connection, also known as slip joint. In a recently published work, a proof of concept of a vibration-assisted installation and decommissioning technique of a slip joint was illustrated. Leveraging on the obtained results, the current study shows for the first time a decommissioning campaign carried out using a vibration-assisted technique applied on a prototype hydraulic wind turbine tower located in the North Sea, and connected to the monopile through a slip joint. The key aspect of the dismounting procedure is a priori knowledge of the resonance frequency clusters corresponding to the slip joint’s cross-sectional modes. Therefore, field hammer tests and experimental modal analysis were carried out inside the wind turbine tower. The identified frequencies and mode shapes were then compared with numerical ones estimated by a finite element model of the investigated structure. The comparison showed that a set of frequency clusters can be directly selected from a detailed numerical model. The preparatory work of the slip joint decommissioning was then executed by installing electric shaker devices, based on the dynamic identification results, and hydraulic jacks mounted inside the wind turbine tower. A first decommissioning trial was carried out in May 2019, while the final decommissioning was performed in August 2019. After analysing the measurements of the hydraulic pressures, displacements and excitation frequencies during the decommissioning campaigns, the results showed that it is possible to disconnect the slip joint if, in combination to a vertical static force, one of the identified cross-sectional mode shapes is excited. The vibration-assisted decommissioning proved to be a successful technique to dismount the connection in a controlled and straightforward manner.     

Locomotion by mechanical pectoral fins

The objectives of this study were the development of a new device for maneuvering an underwater vehicle using the mechanism of a fish swimming, an experimental and theoretical analysis of the hydrodynamic characteristics of the device, and its application to maneuvering a fish robot. Observations and experimental analysis of the pectoral fins of a black bass (Micropterus salmoides) revealed that the locomotion of the fish, such as swimming forward at low speed, swimming backward, and turning in a horizontal plane is generated by using a combination of a feathering motion and a lead-lag motion of the pectoral fins. A mechanical pectoral fin making a feathering motion and a lead-lag motion generates a thrust force in a range of phase differences between both motions. The unsteady vortex lattice method, including the effect of viscosity, can express fairly well the unsteady forces acting on the mechanical pectoral fin in the range of phase differences where it exerts the thrust force. The fish robot, consisting of a model fish body and a pair of mechanical pectoral fins, can not only swim forward and turn in almost the same position, but can also swim in a lateral direction without changing the yaw angle. Translation of an article that appeared in the Journal of The Society of Naval Architects of Japan, vol. 182 (1997): The original article won the SNAJ prize, which is awarded annually to the best papers selected from the SNAJ Journal, JMST, or other quality journals in the field of naval architecture and ocean engineering.     

Optimal reefer slot conversion for container freight transportation

Given a fleet of container ships of varying capacity, a cost-efficient approach for improving fleet utilization and reducing the number of delayed containers is to optimize the sequence of container ships in a given string, a problem which belongs to the large ship-deployment class. A string sequence with ‘uniformly’ distributed ship capacity is more likely to accommodate a random container shipment demand. The number of one’s total ship slots acts as a gauge of the capacity of the container ships. Meanwhile, there are two types of ship slots: dry slots and reefer slots. A dry slot only accommodates a dry container, while a reefer slot can accommodate either a dry or a reefer container. The numbers of dry and reefer slots for ships in a string are different. Therefore, in this study, we propose a model that considers both dry and reefer slots and use it to elucidate the optimal ship-deployment sequence. The objective is to minimize the delay of dry and reefer containers when the demand is uncertain. Furthermore, based on the optimal sequence deduced, the study also investigates the need to convert some dry slots to reefer slots for the container ships.     

船舶弃船决策系统分析

当船舶发生海难事故后,船舶弃船时机的正确决策关系到船舶安全尤其是海上人命安全,文中试运用决策理论与技术以及系统理论分析了该决策系统的目标与准则、决策环境、决策体制与决策者、决策方案等要素,以及这些要素的相互联系,对弃船时机的正确选择做一个初步分析,为进一步研究奠定一些基础。     

线性水波理论中远场无波势的构建(英文)

Various water wave problems involving an infinitely long horizontal cylinder floating on the surface water were investigated in the literature of linearized theory of water waves employing a general multipole expansion for the wave potential. This expansion involves a general combination of a regular wave, a wave source, a wave dipole and a regular wave-free part. The wave-free part can be further expanded in terms of wave-free multipoles which are termed as wave-free potentials. These are singular solutions of Laplace’s equation (for non-oblique waves in two dimensions) or two-dimensional Helmholz equation (for oblique waves) satisfying the free surface condition and decaying rapidly away from the point of singularity. The method of constructing these wave-free potentials is presented here in a systematic manner for a number of situations such as deep water with a free surface, neglecting or taking into account the effect of surface tension, or with an ice-cover modelled as a thin elastic plate floating on water.     

A risk assessment model with systematical uncertainty treatment for container shipping operations

ABSTRACT

The substantial adverse effects of risk factors on container shipping and logistics promoted a deep integration of risk analysis into the decision-making process. This paper aims to develop a well-grounded quantitative model to operational risk in a container shipping context. Considering uncertainty as a primary component of the risk concept, methods were employed in an inter-complementary manner to enable not only a sense of foreseeability but also a deeper look into the weaknesses of the knowledge base. The intersubjectivity of the input extraction process was supported by the Evidential Reasoning (ER) algorithm. Risks are then assessed based on a Fuzzy Rules Bayesian Network (FRBN) model with a 2-level parameter structure before meaningful interpretations can be derived through a new risk mapping approach. Besides an illustrative case study, the model was tested by sensitivity analysis and an examination of multiple validity claims.     

Automatic two-dimensional layout using a rule-based heuristic algorithm

 Efficient layout strategies are introduced for automatic nesting using a rule-based heuristic approach to improve the layout efficiency. Since a large portion of the complexity of the parts layout problem results from the overlapping computation, geometric redesign techniques are also suggested to reduce the complexity of the problem for a fast and reliable means of performing overlapping computation. A new heuristic sliding technique is developed to find a near-optimum layout location from all the feasible arrangements in such a manner that two or more arbitrary parts do not overlap or intersect. An identification method with a pivoting point is suggested to calculate the boundary of the overlap region in a fast computation time-frame. Resource plate clipping using virtual memory, based on a polygon clipping algorithm, is also proposed as a technique to reduce the geometric conditions of the resource plate and the overlap computation time by updating a new stock boundary of the resource plate for the layout space of the next part after each part is placed. The aim of this article is to develop a rule-based heuristic nesting system to achieve a new automatic layout on the AutoCAD system. For this implementation, some nesting examples are demonstrated. A rule-based heuristic approach can be desirable in terms of the layout efficiency and considering the computational time for nesting problems, and is proposed as a real-time layout simulation method in the industrial field. Received: October 7, 2002 / Accepted: March 27, 2003 RID="*"     

Progressive collapse analysis of ship hull girders subjected to extreme cyclic bending

This paper introduces a novel analytical method to predict the buckling collapse behaviour of a ship hull girder subjected to several cycles of extreme load. This follows the general principles of the established simplified progressive collapse method with an extended capability to re-formulate the load-shortening curve of structural components to account for cyclic degradation. The method provides a framework for assessing residual hull girder strength following a complex series of unusually extreme load events where the wave induced bending moment rises close to, or even surpasses, the monotonic ultimate strength. These load events may be sequential, such as might be caused by a series of storm waves, or they may occur as a collection of discrete events occurring over a longer period. The extreme cyclic bending amplifies the distortion and residual stress initially induced by fabrication in the flanges of the girder, which results in a deterioration of the residual ultimate strength. Validation is firstly completed through a comparison with previously published experimental work and secondly via comparison with numerical simulation on four ship-type box girders using the nonlinear finite element method.     

影响船舶弃船时机决策的各环境因素分析

当船舶发生海难事故后,船舶弃船时机的正确决策关系到船舶安全尤其是海上人命安全,本文分析了影响该决策行为的各种环境因素,对弃船时机的正确选择做一个初步分析,为进一步研究奠定一些基础。     

沿海客箱船主尺度的确定

本文首先定义了一个这和船等级评定标准，建立了应用神经网络理论估算客（货）船造价和客舱（位）平均面积的模型，据此编制了确定客箱船主尺度的程序系统，并给出了优选客箱船主尺度的计算例子。