舰船无线通信设备的干扰建模和性能分析

利用随机几何理论建立了舰船无线通信设备的干扰模型,并在此基础上分析了多种信道参数对无线通信设备性能的影响.本文首先理论分析了在舰船环境下的无线通信干扰源分布的系统模型.其次,基于随机几何理论讨论了船体区域中的干扰对无线通信设备性能的影响,并给出了干扰和积分形式的表达式.最后仿真分析了多种无线通信信道参数对设备性能的影响.仿真结果表明,信道状况对无线通信设备的性能有很大的影响,合理部署无线通信设备可有效的改善无线通信性能.     

基于灰色 Markov模型的我国远洋船舶货运总量预测*

对我国远洋船舶货运总量的预测关系到我国港口建设和航运发展的一系列科学规划,也关系到远洋运输在综合交通运输中的比重和国际海上运输的资源分配。单纯的灰色模型对明显单调的序列往往预测得较好,而对波动的序列则会出现精度不够理想的问题。在结合改进后的灰色预测模型和M arkov模型的理论优势后,先用改进后的灰色模型来预测远洋船舶货运总量的总体走势,再用M arkov模型来确定各种状态间的转移方式,以此提高对波动序列的预测精度,具有较高的实用价值。     

Numerical simulation of the water entry of a structure in free fall motion

To solve the problems concerning water entry of a structure, the RANS equations and volume of fluid （VOF） method are used. Combining the user-defined function （UDF） procedure with dynamic grids, the water impact on a structure in free fall is simulated, and the velocity, displacement and the pressure distribution on the structure are investigated. The results of the numerical simulation were compared with the experimental data, and solidly consistent results have been achieved, which validates the numerical model. Therefore, this method can be used to study the water impact problems of a structure.     

Scheduling highway work zones with genetic algorithm considering the impact of traffic diversion

Highway work zones caused excessive delay to road users. To reduce user and maintenance costs, work zones shall be designed and scheduled accordingly. An analytical model is developed to jointly optimize work zone lengths and schedule as well as diverted traffic volume for highway maintenance projects, considering time‐varying demand, variable maintenance cost, and various production rates of maintenance crew. With a genetic algorithm, an iterative procedure is developed to search for the optimal solution. A numerical example is illustrated, in which various traffic mitigation plans for a highway maintenance project are evaluated. A sensitivity analysis is conducted, and results indicate the threshold volumes for various conditions (e.g., maintenance crews and capacity of the work zone) at which diverting traffic is desirable. This study demonstrates an effective approach to search for the optimal work zone schedule, which is also applicable to evaluate the effectiveness of traffic diversion plans for a pre‐planned work zone schedule. Copyright © 2012 John Wiley & Sons, Ltd.     

基于颜色差分特性的图像篡改检测

由于自然场景中目标物体表面的反射特性,以及图像采集过程中的CFA插值算法会使得图像三颜色分量之间具有相关性,特别是颜色分量的高频信息之间有近似相等的关系.拼接篡改操作会降低颜色高频分量的谱间相关性,同时也会给图像带来额外的高频信息.本文利用自然图像颜色通道高频分量之间的相关性,分析颜色差分图像中高频信息的分布情况来检测是否有拼接篡改操作.实验证明本文提取的高频特征分类效果较好,能够检测出图像的拼接篡改边缘.     

《温州市城市道路综合整治全要素技术导则》技术要点解读

为规范道路整治设计,提升城市道路综合品质,温州市专题组织编写《温州市城市道路综合整治全要素技术导则(试行)》(以下简称《导则》)。本文介绍了该导则的编制背景和编制理念,并通过对温州市街道整治全要素设计导则与常规道路设计规范进行对比,就其中道路空间布置、路面质量、附属设施等主要技术要点进行了解读,《导则》结合温州市地方实际,赋予道路更多设计要素,将对后续工程设计的优化提升发挥积极作用。     

基于机器学习的舰船机电装备故障诊断

随着信息技术的发展,以机器学习、模式识别为代表的人工智能技术在故障诊断领域逐步得到应用。通过对振动噪声信号的采集,利用时频分析技术对信号进行分解,并提取故障特征参数,再利用机器学习或模式识别技术对信号进行判别分类,可以实现舰船机电装备的智能诊断。为了验证该方法,选择经验模态分解方法进行信号分解,采用支持向量机进行诊断分类。通过实验表明,该方法有着较高的诊断精度,故障诊断率达到了96.7%,可以对舰船机电装备常见故障进行准确的智能诊断。     

跨越高速公路桥梁钢-混凝土组合梁施工方案研究

以某钢-混凝土组合梁跨越既有高速公路施工为例,通过方案比选,确定了适合该工程的跨越方案.详细论证了该工程顶推施工方案的各个环节,优化了钢梁安装方案,减少了对既有高速公路的影响,保障了跨越施工的安全,可供类似跨越工程参考和借鉴.     

由实测孔隙水压力数据推算软黏土的固结系数和固结度

利用上海浦东某工程实测孔隙水压力推算软基固结系数和固结度，推算结果符合实际土体的团结过程。     

Aesthetic visual style assessment on Dunhuang murals

Dunhuang murals are gems of Chinese traditional art. This paper demonstrates a simple, yet powerful method to automatically identify the aesthetic visual style that lies in Dunhuang murals. Based on the art knowledge on Dunhuang murals, the method explicitly predicts some of possible image attributes that a human might use to understand the aesthetic visual style of a mural. These cues fall into three broad types: ① composition attributes related to mural layout or configuration; ② color attributes related to color types depicted; ③ brightness attributes related to bright conditions. We show that a classifier trained on these attributes can provide an efficient way to predict the aesthetic visual style of Dunhuang murals.