多层次灰色综合安全评价法在油港储运中的应用

通过构建油港储运系统评估指标体系,建立多层次灰色变权综合安全评价模型对研究对象进行评价,并且在评价过程采用层次分析方法确定权重.实例结果表明,多层次灰色综合评价结果具有较强的客观性,能给决策者提供比较可靠的判断依据.     

客运专线车站旅客服务质量灰色评价模型

针对旅客对车站服务质量要求逐渐增高这一情况,根据系统工程的基本原则和思路,以车站旅客服务质量的安全性、舒适性、快捷性和智能性为基本因素,建立旅客服务质量多层次评价体系,将层次分析法和灰色系统理论结合,构建旅客服务质量多层次灰色评价模型,最后将该模型应用到一个客运专线车站上,对其旅客服务质量进行综合评估,结果表明灰色多层次评价模型适用于对车站旅客服务质量进行综合客观的评价,具有较好的实用性。     

基于灰色理论的船舶避碰行动评价

分析灰色评价方法的优越性,并建立避碰行动评价相关数学模型和评价指标体系,最终阐述了基于多层次灰色综合评价理论进行避碰行动评价步骤.该方法具有一定的有效性和实用性.     

既有桥梁技术状态的多层次灰色评判

在多层次灰色评价法的理论基础上 ,探讨了多层次灰色评价法在既有桥梁管理中的应用。建立了桥梁技术状态多层次灰色评价模型 ,并给出了对三座桥梁进行综合评判的实例。为了使描述各灰类程度的评价信息都发挥作用 ,将评价者的分散信息处理成一个描述不同灰类程度的权向量 ,对其进行单值化处理 ,可得到被评桥梁的综合值 ,从而对被评桥梁技术状态排序。结果说明 ,多层次灰色评价法适用于对既有桥梁进行客观公正的综合评价 ,为制定合理可行的桥梁维修计划提供依据 ,有利于推进既有桥梁管理与维修决策的科学化     

灰色理论及其应用研究

将灰色系统理论运用到教学评价的实践中，应用灰色系统理论与方法建立灰色多层次决策关联模型，并给出了考试试卷评价的指标体系与评价标准、量化标准和应用灰色多层次决策关联模型评价试卷的方法．运用此模型及评价指标对任意抽查的5门学科的试卷质量进行了综合评价，获得了比较满意的效果．     

基于灰色理论的供应链成员企业可靠性综合评价研究

给出了供应链成员企业可靠性的多层次评价指标体系,根据其特点,结合灰色理论的方法,建立了供应链成员企业可靠性多层次灰色关联度综合评价模型,并通过一个实例验证了该模型的可行性和应用价值。     

多层次灰色评价法在新产品评估中的应用

在多层次灰色评价法的理论基础上,着重探讨了多层次灰色评价法在新产品评估中的应用。并给出了对三种新产品进行综合评估的实例,为了使描述了各灰类程度的评价信息都发挥作用,将评价者的分散信息处理成一个描述不同灰类程度的权向量,对其进行单值化处理,可得到被评产品的综合值,从而进行被评产品排序选优,结果说明,多层次灰色评价法适用于对新产品进行客观公正的综合评价,有利于推进科技评估管理与决策的规范化。     

基于UML的航运物流能力灰色综合评价模型

传统的航运物流能力综合评价方法受到评价数据过多的影响,导致评价准确度较低,为此设计一个基于UML的航运物流能力灰色综合评价模型.采用UML技术对航运物流数据进行了建模,基于模型数据,引入层次分析法,建立了航运物流能力评价指标体系,处理专家评价等零散信息,计算了多层次指标的权重,描述不同灰度的权重向量,完成基于UML的航运物流能力灰色综合评价,获取受评对象的综合评价值.实验结果表明,此次研究的基于UML的航运物流能力灰色综合评价模型有效提高了评价准确度,并减少了评价时间.     

城市公交线网评价的灰色关联模型

利用灰色系统中的关联度,对城市公交线网的评价问题进行了研究．在综合考虑城市公交系统多种影响因素的基础上,建立了城市公交线网的评价指标体系．在定义评语等级的基础上,通过定量分析为主、定性分析和定量分析相结合的方法,将评价指标值量化处理地情况下,建立了城市公交线网多层次评价的灰色关联模型．该模型将城市公交线网的多层次评价转化为单层评价,比较简明准确地反映出公交线网发展现状．用它对某市现有公交线网进行了综合评价,结果表明该法科学合理、简单易行．     

基于多层次灰色评价方法的绿色住宅结构设计评价研究

为解决绿色住宅结构设计中结构环境性能的改善以及其他与结构系统有关的环境问题,在对我国绿色住宅的结构设计评估体系进行研究的基础上,初步提出绿色住宅结构设计评价体系,通过运用多层次灰色评价方法分析、计算绿色住宅结构设计方案的综合评价得分,从而评价其所属等级,并通过实例验证了该方法的实用性和科学性.     

Simultaneous localization and mapping of autonomous underwater vehicle using looking forward sonar

A method of underwater simultaneous localization and mapping (SLAM) based on on-board looking forward sonar is proposed. The real-time data flow is obtained to form the underwater acoustic images and these images are pre-processed and positions of objects are extracted for SLAM. Extended Kalman filter (EKF) is selected as the kernel approach to enable the underwater vehicle to construct a feature map, and the EKF can locate the underwater vehicle through the map. In order to improve the association efficiency, a novel association method based on ant colony algorithm is introduced. Results obtained on simulation data and real acoustic vision data in tank are displayed and discussed. The proposed method maintains better association efficiency and reduces navigation error, and is effective and feasible.     

水下目标低频散射特性的波叠加解法

针对运用边界积分方程法研究低频散射特性时,存在的表面奇异积分和特征频率处解的非惟一性等问题,将波叠加法引入到水下目标低频散射研究中.对刚性球体的低频散射计算表明,该方法较边界积分方程法不仅消除了奇异解和多值问题,而且具有更高的计算速度和精度,适用的频率范围更宽,可用于水下目标低频散射问题的研究.分析表明影响其计算精度的因素主要是虚源空间位置、目标表面与虚源表面划分精细程度.     

Wavelet moment invariants extraction of underwater laser vision image

Wavelet moment invariants are constructed for object recognition based on the global feature and local feature of target, which are brought for the simple background of the underwater objects, complex structure, similar form etc. These invariant features realize the multi-dimension feature extraction of local topology and invariant transform. Considering translation and scale invariant characteristics were ignored by conventional wavelet moments, some improvements were done in this paper. The cubic B-spline wavelets which are optimally localized in space-frequency and close to the forms of Li＇s （or Zernike＇s） polynomial moments were applied for calculating the wavelet moments. To testify superiority of the wavelet moments mentioned in this paper, generalized regression neural network （GRNN） was used to calculate the recognition rates based on wavelet invariant moments and conventional invariant moments respectively. Wavelet moments obtained 100% recognition rate for every object and the conventional moments obtained less classification rate. The result shows that wavelet moment has the ability to identify many types of objects and is suitable for laser image recognition.     

Wave Number Method for Three-Dimensional Steady-State Acoustic Problems

Based on the indirect Trefftz approach, a wave number method (WNM) is proposed to deal with three-dimensional steady-state acoustic problems. In the WNM, the dynamic pressure response variable is approximated by a set of wave functions, which exactly satisfy the Helmholtz equation. The set of wave functions comprise the exact solutions of the homogeneous part of the governing equations and some particular solution functions. The unknown coefficients of the wave functions can be obtained by enforcing the pressure approximation to satisfy the boundary conditions. Compared with the boundary element method (BEM), the WNM have a smaller system matrix, and is applicable to the radiation problems since the wave functions are independent of the domain size. A 3D acoustic cavity is exemplified to show the properties of the method. The results show that the wave number method is more efficient than the BEM, and it is fairly accurate.     

Modified numerical model for simulating fluid-filled structure response to underwater explosion with cavitation

In this paper, a numerical method is established to analyze the response of fluid-filled structure to underwater explosion with cavitation and the validation of the method is illustrated. In the present implementation, the second-order doubly asymptotic approximation （DAA2） other than curved wave approximation （CWA） is used to simulate non-reflecting boundary. Based on the method, the difference between DAA2 non-reflecting boundary and CWA non-reflecting boundary is investigated; then, the influence of internal fluid volume and the influence of cavitation on dynamic response of spherical shell are analyzed. Compared with CWA non-reflecting boundary, DAA~ non-reflecting boundary treats added mass effects better. When the internal fluid is full, the displacement and velocity of spherical shell decrease, but, when the internal fluid is half, the displacement and velocity of spherical shell increase. The effect of cavitation is more obvious at the trailing point than at the leading point of spherical shell.     

An range-free localization scheme for large scale underwater wireless sensor networks

In this paper, we study an area localization problem in large scale underwater wireless sensor networks (UWSNs). The limited bandwidth, the severely impaired channel and the cost of underwater equipment all make the underwater localization problem very challenging. Exact localization is very difficult for UWSNs in deep underwater environment. We propose a range free method based on mobile detachable elevator transceiver (DET) and 3D multi-power area localization scheme (3D-MALS) to address the challenging problem. In the proposed scheme, the ideas of 2D multi-power area localization scheme (2D-ALS) and utilizing DET are used to achieve the simplicity, location accuracy, scalability and low cost performances. The DET can rise and get down to broadcast its position. And it is assumed that all the underwater nodes underwater have pressure sensors and know their z coordinates. We evaluate the performances of 2D-ALS and our proposed 3D-MALS schemes under both ideal and non-ideal channel propagation conditions, in terms of localization error and localization ratio. The simulation results show that our proposed scheme is much more efficient than the 2D-ALS.     

利用对称性计算第二类曲线积分与曲面积分的方法

由于第二类曲线积分与曲面积分涉及到方向性问题，因此利用对称性来计算较为困难,文中给出了利用对称性计算第二类曲线积分与曲面积分的方法，并证明了方法的可行性，并通过实例表明，此方法有时能起到简化计算的作用．     

A low-cost testbed of underwater mobile sensing network

Comprised by a swarm of acoustically linked and cooperative autonomous underwater vehicles (AUVs) with onboard sensors, an underwater mobile sensing network (UMSN) will be a complementary means to fixed observatory networks, e.g. seafloor observatory networks and moored buoy arrays. It has obvious advantages over a single large AUV in higher efficiency due to parallel observation, stronger robustness to vehicle failures and lower cost. Although an UMSN can be viewed as a counterpart of wireless mobile sensing networks for air and terrestrial applications, it is much more challenging due to poor performance of underwater acoustic communication, poor performance of underwater positioning and high degree of uncertainty in vehicle dynamics and underwater environment. In order to verify key technologies involved in an UMSN, e.g. cooperation of multi-AUVs based on acoustic communication, a low cost testbed has been developed for experimental study. The design of both hardware and software is introduced. Also the results of a functional test for verification of the effectiveness of the testbed are presented.     

移动最小二乘微分求积法解Helmholtz方程

用一种新型的数值方法--移动最小二乘微分求积法（MLSDQ）求解二维Helmholtz方程。MLSDQ方法是一种直接将微分方程离散的方法，它是将未知函数的各阶偏导数在离散点处的值用域内各配点的函数值加权组合来表示，权系数则直接用移动最小二乘Galerkin法中的形函数求导得到，通过MLSDQ技术将Helmholtz方程和相应的边界条件转化成为一组关于各配点位势的线性代数方程组，求解这组代数方程，便可得到各配点的位势，通过求解几个具有精确解的算例，讨论了方法的收敛性和数值精度，结果表明：该方法较适合于求解小波数的Helmholtz方程,对高波数的方程，需要设置大量的域内配点才能有较好的数值结果。     

远场大转角时水下典型目标回波建模与成像

为了解决当水下目标位于声呐远场且转动角度较大时,运用距离-多普勒算法成像存在的图像模糊难题,基于物理声学方法建立了此时水下典型目标的回波信号模型,运用极坐标格式算法对目标进行成像,讨论了不同的插值算法对成像效果的影响,实现了刚性有限长圆柱体和椭球目标成像.仿真结果表明成像效果良好,有效克服了散射点越分辨单元走动的影响.