动力定位时时域模拟程序试验验证

在启用新的动力定位系统时,数值和试验验证方法,包括静态动力定位能力分析、动态的时域模拟和模型试验应该用来设计,分析和预测新系统的性能。为了精确并经济地验证动力定位系统的性能,在Matlab\Simulink环境中,开发了一个能够进行一个"试验"来评估一个新设计的动力定位系统和其子系统的程序。另外,这个新开发的动力定位时域模拟程序的可靠性通过对一个半潜平台的模型试验进行了评估。结果表明,这个程序可以作为一个船舶研究工具用来检验新设计的动力定位系统或其新模块。     

基于CPC的大型定制产品全寿命敏捷供应链信息模型研究

阐述了基于CPC理念的大型定制产品全寿命供应链的功能及其管理目标。为了达到全寿命敏捷设计、制造和供应的目的，在产品设计阶段组成动态联盟．并进行基于CPC平台的全寿命协同设计，生成产品功能配置、制造装配、使用维修信息视图及产品配套计划。再与B2B和B2C供应模式结合，形成制造和使用维修阶段(包括现代化改装)的采购信息视图。论述以上信息视图之间关系的建立是实现供应链信息共享的技术基础。     

基于ARM9的嵌入式Web服务器的研究

研究了基于ARM9的嵌入式Web服务器的软、硬件设计及其实现,其中硬件部分的核心是三星的S3C2410X微处理器,是基于ARM920T内核的RISC型CPU,软件部分采用了源代码开放的Linux操作系统,主要对启动程序U-Boot、嵌入式Web服务器的各模块设计及系统运行等做了论述。     

一种共享动态缓冲的MPNoC路由器设计

在片上多处理系统(Multiprocessor System-on-Chip,MPSoC)中,对路由器缓存区分配策略分析,实现缓冲区动态分配,能够有效提高嵌入式多核处理器芯片多方面的性能。本文了设计一种共享动态Buffer的MPNoC路由器,该路由器可以通过有效分配各通道缓冲资源,实现资源共享。在16节点2D-mesh网络拓扑结构下对静态路由器和本路由器进行仿真分析,实验结果表明,共享动态Buffer的MPNoC路由器与静态路由器相比,具有内存开销低、能量消耗低、平均信息延时小的特点。     

基于CPC的大型定制产品全寿命敏捷供应链信息模型研究

阐述了基于CPC理念的大型定制产品全寿命供应链的功能及其管理目标.为了达到全寿命敏捷设计、制造和供应的目的,在产品设计阶段组成动态联盟,并进行基于CPC平台的全寿命协同设计,生成产品功能配置、制造装配、使用维修信息视图及产品配套计划.再与B2B和B2C供应模式结合,形成制造和使用维修阶段(包括现代化改装)的采购信息视图.论述以上信息视图之间关系的建立是实现供应链信息共享的技术基础.     

基于AIS的舰载雷达标校方法研究

雷达标校是战场精确打击和组网雷达数据融合的前提,为提高舰载雷达数据融合的有效性和目标探测精度,文中提出了基于AIS接收标校目标定位信息的舰载雷达系统标校方法,分析了标校的基本原理和主要误差源,详细给出了目标真值的大地测量主题解算方法,最后得出标校理论精度范围,并通过仿真分析得以验证.该标校方法过程简单,操作方便,真值精度高,通用性强,同时适用于静态标校和动态标校.     

轴系试验台配置式数据采集软件实现方法

针对传统数据采集软件在数据采集、计算和存储等环节紧密耦合,导致代码固化和软件功能调整不便等问题,文章提出基于配置方式的轴系试验台数据采集改进方法,将数据采集卡各通道的计算规则和存储规则提炼成程序配置信息,以配置信息定义采集业务处理方式,程序运行时动态解析配置实现自定义采集功能。通过软件测试,程序正确解析了配置信息,实现了用户自定义的采集任务。在不修改代码的情况下,用户可以根据需求修改、增加或删除配置信息以调整采集业务处理方式,实现采集软件良好的灵活性和扩展性。     

我国VTS系统数据交换格式最新实践

结合欧盟SSN研究报告和我国有关VTS数据格式标准化研究成果,分析了我国VTS数据交换的具体内容。针对船舶动态位置信息、船舶静态信息和船舶航程相关信息,定义了基于电文和XML的两种数据交换格式。     

在C^＋＋程序中合理使用内存

本文介绍了C 程序的内在组织方式，说明了系统堆栈和动态内存二者的区别以及各自使用特点、注意事项等，并举例阐述了如何选择数据的存储方式，使自己的应用程序合理地使用宝贵的内存资源。     

新时期加强档案编研工作的对策研究

档案编研工作是对档案资源收集研究，进行加工输出，将静态的档案资源转化为动态的档案信息，为各方面的利用者提供科学、完整、系统的档案服务的一项档案业务工作。新时期进一步加强档案编研工作，对促进开发档案信息资源，向社会提供档案信息服务具有积极作用。目前，由于各方面原因，档案编研工作普遍存在编研选题范围较窄、编研成果质量偏低等现实问题，     

波斯湾中受随机波作用的某新建离岸导管架平台时域动力分析研究（英文）

API RP2 A WSD is a design code in practice for design of jacket platforms in the Persian Gulf but is based on the Gulf of Mexico environmental condition. So for the sake of using this code for the Persian Gulf, it is better to perform a calibration based on this specific region. Analysis and design of jacket platforms based on API code are performed in a static manner and dynamic analysis is not recommended for such structures. Regarding the fact that the real behavior of the offshore jacket platforms is a dynamic behavior, so in this research, dynamic analysis for an offshore jacket platform in the Persian Gulf under extreme environmental condition is performed using random time domain method. Therefore, a new constructed offshore jacket platform in the Persian Gulf is selected and analyzed. Fifteen, 1-h storm, simulations for the water surface elevation is produced to capture the statistical properties of extreme sea condition. Time series of base shear and overturning moment are derived from both dynamic and static responses. By calculating the maximum dynamic amplification factor(DAF) from each simulation and fitting the collected data to Weibull distribution, the most probable maximum extreme(MPME) value for the DAF is achieved. Results show that a realistic value for DAF for this specific platform is 1.06, which is a notable value and is recommended to take into practice in design of fixed jacket platform in the Persian Gulf.     

基于误差分析的DCT域图像隐藏算法

为有效减少在AWGN信道下取整误差对秘密信息提取造成的影响,通过分析取整误差、DCT系数误差和秘密信息提取误差三者的关系,得出DCT系数误差是服从N（0,0.0833）正态分布,进而推导出在DCT域扩频算法和量化索引调制（QIM）盲提取算法中秘密信息提取误差的概率密度函数。基于误差分析分别提出采取容错和纠错编码方式的两种改进算法,提高图像隐藏的隐蔽性和秘密信息提取的准确率。仿真结果验证了这两种算法的可行性和有效性。     

基于神经网络的声纳特征级信息融合中目标分类研究

声纳目标特征级融合的主要任务是实现信息压缩、目标身份确定(分类) ,以利于实时处理、决策分析。基于数学模型的各种算法,由于情况复杂,往往很难建立。而人工神经网络通过样本的学习,具有存储记忆、在相似输入下能恢复记忆等特性,从而避免了烦琐而复杂的建模。在神经网络声纳目标识别前的噪声预处理方法中,选用了功率谱特征提取、双谱特征提取算法;在研究了提取的特征后,选取反向传播神经网络(BP)模型;在此基础上构造了BP神经网络,并对网络进行训练与测试,给出识别实验结果。仿真模拟分析证明,基于神经网络的声纳特征级信息的融合,对目标分类有一定效果,为进一步实现声纳信息融合奠定了基础     

自升式钻井平台的抗冰性能评价

自升式钻井平台属于典型的柔性结构。由于冰与柔性抗冰结构相互作用的复杂性,长期以来尚未形成基于动冰力响应分析的结构设计。结构抗冰设计中大都是从极端荷载出发,只考虑最大静冰力或最大倾覆力矩是否能推倒平台。基于对渤海辽东湾柔性抗冰平台的多年监测,发现强烈的冰激振动引起平台管节点疲劳失效、上部设施的非正常运行、作业人员不舒适等问题的风险性要远大于极端静冰荷载下结构的整体安全问题。文中基于多年现场冰与结构作用观测及冰荷载的研究成果,提出了柔性抗冰结构设计中应考虑的主要失效模式及评价方法。最后,以渤海某典型自升式钻井平台为例,对其抗冰性能进行评价。该文的研究可为寒区自升式平台的抗冰概念设计提供合理依据。     

基于模糊PID控制器的门式起重机大车定位控制系统研究

以门式起重机大车准确定位问题为研究对象,根据准确定位作业控制和系统动态性能的要求,设计了基于模糊PID控制器的准确定位控制系统,并利用MATLAB语言对门式起重机大车运行定位系统进行了仿真。仿真结果表明,这种复合控制方法,不仅保持了模糊控制器原有的鲁棒性,而且响应时间短,稳态误差小,达到较理想的控制性能目标。     

燃机进口导叶电液加载系统建模与优化仿真

现有电液加载系统研究具有控制对象模型不够准确直观,加载精度不高的缺点。针对控制对象具有复杂非线性以及加载机构运动严重影响加载精度的问题,提出了利用基于物理网络概念Simscape工具进行准确直观的非线性建模,设计了惯性力矩补偿+基于力加载误差和受力界面速度信号的模糊补偿环节用于补偿加载机构运动造成的扰动以提高力加载精度。对燃机进口导叶气动力矩电液模拟加载系统的建模过程体现了利用Simscape工具带来的直观可靠的优势,仿真实验表明新控制策略能显著提高加载精度。     

Three-dimensional equivalent static analysis for design of submerged floating tunnel

Stress evaluation of a submerged floating tunnel (SFT) is an issue important for determining the section dimensions required to resist environmental loads. However, the complex interaction between an SFT and surrounding fluid has confined most research on SFTs to longitudinal global time-history analyses based on Morison's equation [1]. Even though these analyses give sufficient information in the longitudinal direction, too little information about the circumferential direction compels an SFT section to be designed conservatively. This means that SFT design requires additional information on the structural behavior of the tunnel in the circumferential direction for efficient design. Accordingly, a supplementary approach by which to obtain structural responses in the circumferential direction is introduced in this paper. Upon consideration of the static responses equivalent to the dynamic behavior, three-dimensional (3-D) finite-element analyses of an SFT were performed by application of static loads corresponding to dynamic loads equivalent to those of wave, current and earthquake. The validation of each equivalent static load was supported by the results from comparison of the tension forces in mooring lines obtained using OrcaFlex [2] and ABAQUS [3]. These were used mainly for longitudinal dynamic analysis and 3-D stress evaluation, respectively, of an SFT. Based on the stresses obtained in the longitudinal and circumferential directions, the selection of suitable section dimensions for an SFT is considered.     

Equivalent linear pseudostatic and dynamic modelling of vertically vibrating monopile

To optimize offshore wind turbine (OWT) design, an engineering tool has been developed allowing for a detailed investigation of the effects of nonlinear soil stiffness and damping on foundation dynamics. We have studied the response of a vertically oscillating offshore wind monopile foundation in a realistic soil profile subjected to loads between 1 and 200 MN in the frequency range 0–10 Hz with pseudo-static and equivalent linear dynamic model. The non-linear soil behaviour is modelled with an equivalent linear method with shear modulus reduction and damping curves as input. The tool is verified and validated by comparison with elasto-dynamic model and experiments. With increasing load amplitudes foundation stiffness increases and damping decreases. For large load amplitudes the lower part of the pile foundation contributes more to foundation damping. The results indicate the nonlinear foundation stiffness and damping can be modelled rationally by combining stiffness and hysteretic damping from nonlinear static tools with apparent mass and radiation damping from elasto-dynamic analysis. The tool can be used to compute soil springs and dampers based on laboratory-based soil stiffness and damping.     

阵列式皮带秤与新法倾斜补偿装置在移动式装卸设备上的应用

分析与移动式装卸机械相连的皮带秤的特征,介绍一种能安装在工作时悬臂位置变动的移动式装卸机械上的高准确度皮带秤。该秤在倾角固定状态下动态累计误差能长期保持在±0.2%以下,采用独创的非几何量补偿方式的三维姿态跟踪装置来修正悬臂倾角变化对称重结果的影响。计量机构对在不同大小倾角及倾角变动过程中的计量性能进行实测,结果表明,在各种位置状态下的动态累积误差均优于0.5级准确度的指标。     

Application of a genetic algorithm to the optimal structural design of a ship's engine room taking dynamic constraints into consideration

The genetic algorithm, known as GA, is used to optimize engine room structure, not only under static constraints, but also under dynamic constraints. A penalty function method is used to handle the complicated constraint conditions based on the numerical results of dynamic and static analyses. There are several ways to take the dynamic effect into account in the optimum design of ship structure. First, the inequality constraint condition is applied to separate the natural frequency and the exciting frequency. Second, generalized design variables are introduced in order to transfer not only the dynamic but also the static equilibrium equations into the equality constraints, resulting in the optimal structural design without the need to solve these equilibrium equations. Third, the magnitudes of the acceleration and displacement are constrained instead of applying the natural frequency constraint condition. In order to achieve better convergency in the optimization with least resources, several operators and methods are considered and then introduced into the structural design of the engine room. The new operator, called either objective elitism or fitness elitism, is introduced to improve the efficiency of the method. The effect of boundary mutation and nonuniform mutation on the performance of the GA is examined. Not only binary representation but also floating-point representation are used to express the design gene in the GA. Fuzzy theory is applied in the GA to handle the uncertainty of the constraint conditions. Two ways of solving fuzzy optimization are investigated in order to obtain a fuzzy solution and a crisp solution. Received: October 2, 2000 / Accepted: November 30, 2000