船舶柴油机缸套冷却水系统动态特性建模与仿真

提出一种简单、可靠的船舶柴油机缸套冷却水系统建模与仿真分析方法,利用阶跃响应法获取现场试验数据,采用"两点法"得出模型参数,在MATLAB软件环境下,采用"曲线拟合法"对模型参数进行修正,实现系统动态特性建模。对模型进行了仿真分析与实验结果比较,表明模型是可信的。     

基于VC++和MATLAB的船舶电力系统动态仿真软件开发

为分析船舶电力系统的性能和特点,常常借助仿真平台进行研究。结合VC++和MATLAB各自的优点,提出一种基于两者混合编程的方式并应用于开发船舶电力系统变参数仿真平台,用以动态分析船舶电力系统的各项性能。采用VC++编程实现船舶电力系统可视化绘制、参数设置以及拓扑分析,利用MATLAB强大的计算优势实现复杂的电力系统运算,最后VC++调用MATLAB引擎打开MATLAB实现仿真。该软件平台可实现在不间断原参数仿真运行的前提下,自由地改变系统的结构以及参数设置以实现延续仿真,并实时显示该系统变化时相应的仿真曲线,实现对船舶电力系统性能参数的在线分析。     

基于MATLAB/Simulink的随动控制系统建模与仿真

文章先通过介绍随动控制系统的组成,然后对各组成部分进行数学建模,如:伺服电机、PWM脉宽功率放大器、增量式编码器等,得到整个随动控制系统的数学模型,再设计模型各环节的PID参数,最后通过MATLAB/Simulink进行仿真,得到整个系统的仿真结构图、不同频率输入信号的响应曲线和误差,并进行了带宽分析。通过仿真,验证了控制方案的正确性和可行性,满足设计输入要求。     

Watterson HF信道模型的MATLAB仿真

对Watterson HF信道模型进行了理论推导,分析了模型的MATLAB仿真过程中的算法,用MATLAB编程实现了Watterson HF信道模拟器,在不同信道条件下用2FSK信号作为模拟器输入进行了仿真,给出了仿真参数和曲线,并对仿真结果进行了比较分析。     

舰船噪声非线性特征的信道传播研究

文章首先针对信道的相干多途特性,基于射线理论,利用MATLAB仿真得到了信道的多途参数;接着基于相似序列重复度理论,提取了舰船辐射噪声的非线性特征—序列重复度RPT;最后将舰船辐射噪声通过多途信道作用,提取不同信道作用后的RPT特征并进行对比分析。研究表明,当舰船辐射噪声在不同传播距离和海深的信道里传播时,RPT特征的幅值缓慢变化,且其特征曲线的形状也发生改变,即舰船辐射噪声的RPT特征在多途信道里传播时是不稳定的。     

MATLAB在轮机自动化课程教学中的应用

本文主要介绍MATLAB软件用于直流伺服电机对单位阶跃输入响应的PID校正动态模拟仿真。通过举例说明，MATLAB软件包可以成功应用于轮机自动化课程辅助教学和动态仿真，为该课程的教改提供了广阔的前景。     

一种对海雷达动目标检测系统的设计与分析

动目标检测(MTD)是现代雷达系统中重要的功能之一。文章基于MATLAB/Simulink的仿真环境，运用Simulink模块库中的相位编码波形、雷达目标、运动平台、自由空间传播、距离-多普勒响应和恒虚警（CFAR）检测器等模块，设计和构建了一个具备高距离分辨率和速度分辨率的雷达MTD仿真系统。最后通过仿真实验得到二维速度-距离结果图和CFAR检测结果图，其仿真结果与设计的目标参数一致，说明仿真系统实现了MTD功能和雷达测速、测距的基本功能，并验证了仿真系统的可行性和正确性。     

输液管道流固耦合的响应分析

采用结构有限元方法和流体CFD方法，研究变化流速下结构和流体的瞬态响应，实现管道与流体间的双向耦合，并得到管道位移、水动压力的时间历程曲线。通过MATLAB频域转换得到了结构和流体的响应频率。     

基于MATLAB的卡尔曼滤波法参数辨识与仿真

本文介绍了基于MATLAB的使用卡尔曼滤波法进行参数辨识的设计与仿真方法。简述了参数辨识的概念和卡尔曼滤波法应用于参数辨识的基本原理，结合实例与最小二乘法进行比较，给出了相应的仿真结果和分析。     

发射型钹式换能器的研究

为分析低频钹式换能器的发射电压响应、辐射声功率、发射效率等性能参数,通过ANSYS有限元软件建立了发射换能器的轴对称模型,设计了不同结构参数的共振频率为2kHz左右发射型钹式换能器,从结构阻尼入手,通过仿真分析计算,得到换能器的带宽、品质因数等,比较了不同结构参数的换能器的各项性能,绘制了不同结构参数的发射电压响应曲线,为分析设计钹式换能器提供了理论依据。     

海洋工程中常见焊接缺陷的成因探讨及对策

海洋工程钢结构制造过程中焊接接头、焊缝和热影响区是最容易产生各种缺陷的地方.缺陷,顾名思义是一种欠缺、不足、不完善的地方,也包括物体的损伤.焊接缺陷可定义为不完善焊接施工所导致的工件使用性能的不连续性;也可定义为由于原有或积累的影响,使部件或产品不能满足最低验收标准或规程的一种或多种不连续[焊接缺陷的研究是伴随着焊缝质量检测方法的进步而发展的];故对焊接缺陷及其缺陷对焊接构件承载力的影响程度的研究是很有必要的.该文以外观检测方式、用PL19-3项目中出现的焊接缺陷,探求钢结构焊接缺陷类型、特点及其产生缺陷的成因;并通过具体的案例进行分析,从而达到减少缺陷产生及保证工程质量的目的.     

Perceived Diving Impacts and Management Implications at a Popular South African Reef

Coral reefs are threatened by impacts such as from scuba diving, and ongoing research is required to assess diving impacts, diver behavior and environmental knowledge. This study investigated perceived diving impacts, reef condition and norms among scuba divers at Sodwana Bay (South Africa). Divers viewed contact with coral as damaging, and perceived environmental degradation at dive sites. However, most divers saw activities such as photography as causing little or no damage to reefs. One meter or less was believed to be a safe distance from the reef or the wildlife to avoid contact or disturbance, and encounter norms were high. Age and experience influenced most perceptions, although cannot be accepted as reliable indicators of divers' perceptions or behavior, due to the heterogeneous conduct of divers of various experience and age as described in literature. The importance of human perceptions to understand what strategies need implementation in diving management is discussed.     

Towards a simplified performance-linked value for money model as a reference point for bus contract payments

The burgeoning commitment to contracting the delivery of bus services through competitive tendering or negotiated performance-based contracts has been accompanied by as many contract payments schemes as there are contracts. We are now well placed to design a simplified performance-linked payment (SPLP) model that can be used as a reference point to ensure value for money, given the accumulation of experiences throughout the world which have revealed substantive common elements in contracts. Whether the payment to the operator is framed as a payment per passenger or as a payment per service kilometre, the SPLP identifies efficient subsidy outcomes that are linked to a proxy indicator of net social benefit per dollar of subsidy. We illustrate how the SPLP model can be applied to obtain the gross (subsidy) cost per passenger (or per passenger km) from measures of gross cost efficiency and network effectiveness. This model can then be used as part of a benchmarking activity to identify reference value of money prospects in respect of passengers per $ subsidy outlay by adjusting for influences not under the control of the service provider. A single framework to identify contract payments to operators, and to assess (i.e., benchmark) operator performance on critical KPIs, is provided by internalising critical key performance indicators (KPIs) in the design of the SPLP. The proposed SPLP model is sufficiently general to be independent of the procurement method (competitive tendered or negotiated, for example) and of the treatment of revenue allocation (net or gross based contracts), with the additional advantage of being able to assess value for money for government.     

战舰上合理布设救生艇、筏的探讨

各国海军大、中型水面舰船上各类艇、筏的布设位置大多在舯部附近，极少有不紧靠烟囱的情况。而舯部烟囱附近往往是声场、红外线场、磁场等最强处，在海战中这些部位最有可能被敌方的现代化导弹和制导炸弹击中，从而使艇、筏这类保障官兵生命安全的设备易遭损毁或是被熊熊大火所包围，丧失救生功能。为探求艇、筏的合理布设位置，使用了概率论中的正态分布理论。引举实例，在舰中一弹的前提下，靠近艉部的艇被导弹直接击毁的概率下降为靠近舯部艇的约1／40，安全性显著提高。因此艇、筏应尽可能地布设在战舰的艏艉两端。经过分析推荐了几个比较合理的建议性方案。     

Hierarchical logic in shipping policy and decision-making

Shipping policy is made and implemented under conditions of multiple objectives and constraints. It is often also subject to diverse interests and decision-makers, each with his own agenda. Policy alternatives usually have different financial, economic, market, environmental, and other implications, and, as a result, affect objectives and constraints differently. In turn, their desirability from the point of view of the various decision-makers will be influenced by complex sets of priorities. Shipping policy and decision-making involves the trade-off among a myriad of often conflicting objectives in the choice between alternative strategies. A hierarchical network approach to the determination of the most effective choice or strategy is proposed to represent the effect of policy alternatives on desired and undesired outcomes and the impact of these outcomes on the objectives and, as a result, the various interest groups supporting different policy objectives. The model suggested is based on the analytic hierarchy or expert choice process and permits consideration of both qualitative as well as quantitative performance measures and their impact on policy or decision objectives.     

30万吨FPSO单点系泊系统整体吊装技术研究

FPSO是集油气处理加工、发电、供热、原油产品的储存和外输、人员居住和生产功能于一体的浮式生产储油装置.FPSO通过特殊的系泊系统长期系泊在海上,20年不解脱,能抵御百年一遇的环境条件.通过有限元技术对渤海二期蓬莱19-3油田30万吨FPSO单点系泊系统进行整体吊装仿真分析,从而确定整体吊装方案,实现该特殊结构一次性吊装就位.     

The significance of the International Tribunal for the Law of the Sea for the shipping industry

The International Tribunal for the Law of the Sea (ITLOS) was established by the 1982 United Nations Convention on the Law of the Sea as a body to settle disputes between States Parties to the Convention regarding the interpretation or application of the Convention s provisions, including provisions concerning the exercise of the powers of States over shipping and the discharge by states of their responsibilities and obligations in relation to ships.ITLOS is competent to deal with disputes in which a State is alleged to have wrongly interfered with or otherwise restrained the operation of a vessel when it is in a port of the State or within the territorial sea or exclusive economic zone of the State.In its previous judgments, ITLOS has provided clarifications of some important areas of the law of the sea concerning the operation and regulation of shipping by flag States and other states.ITLOS plays a key role in the regime of the Law of the Sea Convention relating to the prompt release of ships and their crews that are arrested or detained in a foreign port.ITLOS also has the possibility to serve as ajudicial organ for the settlement of disputes under other maritime agreements and contracts, if the parties to the agreements or contracts agree to confer jurisdiction on it.There are many advantages to be gained by States and shipping operators from using ITLOS as the body for the settlement of disputes under agreements. These advantages include savings in time and expenses.     

Flexible transport services: A new market opportunity for public transport

The term Demand-Responsive Transport (DRT) has been increasingly applied in the last 10 years to a niche market that replaces or feeds (usually via small low floor buses or taxis) conventional transport where demand is low and often spread over a large area. More recently, the concept of DRT as a niche market has been broadened to include a wider range of flexible, demand-responsive transport services and is increasingly referred to as Flexible Transport Services (FTSs). The contention of this paper is that well-implemented FTS has the potential to revitalise bus-based public transport services which are traditionally based on fixed networks with variable geographical coverage and levels of service.     

金属风暴武器技术发展综述

金属风暴武器技术是采用弹丸叠装技术和电子点火技术的新型发射技术,具有射速高、火力强大、极高的火力质量比等特点。本文较为全面地论述了金属风暴武器技术的原理、各个方面的发展及改装情况,包括发射药密封、多发射药、点火与不点火排除、现场装弹、大口径武器发射及普通榴弹与可叠装弹丸改装等专利技术。采用这些技术可以解决发射药的有效密封与低成本密封、弹丸初速度的提高与改变、可靠点火与低成本点火、现场再装弹、大口径武器发射及低成本改装等问题。     

Future aspects in marine ecosystem modelling

Existing ecosystem models are briefly presented and summarised. The problem of coupling physical and biological models as well as aspects of prediction and predictability are discussed. The general perception that marine ecosystems are inherently unpredictable due to non-linearity becomes questionable if the response of climate variability in marine ecosystems is analysed. Many authors have shown correlations between climate variability and the variability of abundance or biomass of marine organisms such as phytoplankton, zooplankton, benthos or fish recruitment in different parts of the world ocean. In the northern hemisphere, certain species show a linear response to climate variability mainly during winter and spring. However, the underlying mechanisms are not well understood. Often, a phase lag can be observed between climate variability and the reaction of organisms. The identification of a plausible mediator between climate and biology is difficult, since all possible physicochemical mechanisms having a direct or indirect influence on the variability of abundance or biomass of marine organisms have to be considered as mediator.The understanding of the reason of the phase lag, which possibly implies a “biological memory”, and the identification of all possible mediators are necessary to predict the response of marine organisms to climate variability. The identification of mediators will result in an improvement of coupled models, a deeper understanding of physical–biological interaction and the improvement of predictive capability of marine ecosystem models.