吊放声纳搜索效能通用仿真模型研究

通过对吊放声纳作战机理的详细分析,以蒙特卡洛法为基础建立了吊放声纳搜索效能的通用仿真模型,并通过仿真实例对模型进行了应用和验证.该模型适用于对各种作战条件下使用各种作战方法时吊放声纳搜索效能的仿真计算.     

一种基于GTD模型和状态空间处理的运动目标超宽带散射中心提取方法

超宽带条件下散射中心的不同运动将对参数提取造成影响.基于GTD模型和状态空间处理,本文提出了一种针对运动目标的超宽带散射中心提取方法.该方法首先将超宽带条件下的目标GTD散射模型转化为状态空间方程,通过奇异值分解提取散射中心的径向距离和径向速度信息;然后由标准正交向量基降维表示散射中心在整个带宽上的类型参数信息,采用遍历方法和最小二范数准则求解出散射中心的类型参数信息;最后基于最小二乘法求解出散射中心的散射强度.文中同时给出了各参数估计的CR界.仿真结果验证了文中方法的有效性,该方法可同时提取散射中心径向距离、径向速度、散射强度和类型参数信息,从而有利于各散射中心的跟踪和整体目标的有效识别.     

Image City sharing platform and its typical applications

In this paper,the trend of urban spatial information sharing service from the electronic map to image is analyzed and its sharing framework based on service-oriented architecture is designed.Moreover,the service implementation,feedback data service procedure and its processing service model are explored. Based on the software with independent intellectual property rights,image city of Taizhou is developed as an example to realize various image data and processing servicesLastly,the bright future prospects o...     

信息安全技术的两种大胆思维

本文作者结合国有企业乃至互联网的体系结构,分析了未来的网络发展与新技术的关系,充分强调要以独立发展为主、新技术借鉴为辅的企业网络安全建设理念,提出了改进信息网络安全的两种新设想:一是建立了一种独有的矩阵逻辑模型,解释此种模型如何实现网络资源的动态分配、自维护功能;二是借用医学领域的神经网络概念,将其扩展到网络的安防机制中,提出对受到的网络攻击如何实现网络云自我在控、自动防护、自动隔离的大胆设想。整篇文章围绕着网络架构的安全性、可靠性展开充分论证,思维大胆,分析具体,见解独到。     

电信网络运维阶段风险评估方法研究

安全风险评估是电信网运维阶段安全防护的重要内容,为了深入了解全网的安全状态、控制运行过程中的安全风险,需要建立一套有效的风险评估方法。本文对电信网运维阶段风险评估方法进行研究,提出了一套量化的风险计算方法。该方法不仅可以定量分析网络存在的内在脆弱性和面临的外部威胁,而且可对风险高低情况进行梳理,找出网络运行中的薄弱点,提出安全需求,从而为实施合适的安全防范措施、制定有效的风险控制策略提供理论基础。     

基于聚类的教学资源管理系统

随着信息技术和现代教育技术的发展,教学资源管理系统在各种不同层次的院校被广泛应用,本文基于聚类算法设计并实现一套教学资源管理系统,通过聚类算法能有效提高教学资源的检索效率从而提高教学资源管理系统的总体性能。     

信息安全技术的两种大胆思维

本文作者结合国有企业乃至互联网的体系结构.分析了未来的网络发展与新技术的关系.充分强调要以独立发展为主.新技术借鉴为辅的企业网络安全建设理念,提出了改进信息网络安全的两种新设想:一是建立了一种独有的矩阵逻辑模型.解释此种模型如何实现网络资源的动态分配、自维护功能;二是借用医学领域的神经网络概念.将其扩展到网络的安防机制中,提出对受到的网络攻击如何实现网络云自我在控,自动防护.自动隔离的大胆设想.整篇文章围绕着网络架构的安全性、可靠性展开充分论证,思维大胆.分析具体.见解独到.     

Design reuse oriented partial retrieval of CAD models

As a huge number of 3D CAD models is generated each year, retrieval of 3D CAD models is becoming more and more important for achieving design reuse. However, the existing methods for partial retrieval of 3D CAD models are very few and far from the requirements of design reuse. In this paper, we present an approach to partial retrieval of 3D CAD models for design reuse. The criteria for determining whether a subpart of 3D CAD models is reusable for design is defined first. Based on the criteria defined, all the design reusable subparts involved in the 3D CAD models in the library are automatically extracted and stored in the library as reference models. Moreover, each design reusable subpart in the library is represented by all its local matching regions in a hierarchical way so as to support multi-mode partial retrieval. In our approach, three partial retrieval modes including normal retrieval, exact retrieval and relaxed retrieval are defined to meet various partial retrieval requirements of design reuse such as the incomplete and vague queries during the early design stage. And the multi-mode partial retrieval is achieved by performing multi-mode matching and similarity assessment between the query and the design reusable subparts in the library indexed by bitmap. Experimental results are presented to demonstrate the effectiveness of the approach.     

Identification and optimization of key process parameters in noncontact laser scanning for reverse engineering

This Extended Technical Note shows that the final accuracy level of reverse engineered surfaces depends on scanning distance and scanning angle of the laser beam, hence it also depends on the morphology of the scanned objects. On scanning strongly curved objects, such as the ones with free form surfaces, the distance and impact angle of the laser beam are changing continuously during the scanning process. On the basis of these, two critical parameters are specified for the design model, which make it possible to predict these two factors in advance, depending on the morphology of the scanned object. First, a mathematical-statistical design model of the scanning process is generated, which relies on ANOVA (analysis of variance) and DOE (design of experiments). In the next step, a fitness function is optimized by the genetic algorithm (GA) program. This optimization improves the accuracy of the final scanned surfaces, in terms of the minimum standard deviation values of reverse engineered 3D surface model. The proposed approach was confirmed in a case study, which is presented at the end of this Technical Note.     

Multi-GPU accelerated multi-spin Monte Carlo simulations of the 2D Ising model

A Modern Graphics Processing unit (GPU) is able to perform massively parallel scientific computations at low cost. We extend our implementation of the checkerboard algorithm for the two-dimensional Ising model [T. Preis et al., Journal of Chemical Physics 228 (2009) 4468-4477] in order to overcome the memory limitations of a single GPU which enables us to simulate significantly larger systems. Using multi-spin coding techniques, we are able to accelerate simulations on a single GPU by factors up to 35 compared to an optimized single Central Processor Unit (CPU) core implementation which employs multi-spin coding. By combining the Compute Unified Device Architecture (CUDA) with the Message Parsing Interface (MPI) on the CPU level, a single Ising lattice can be updated by a cluster of GPUs in parallel. For large systems, the computation time scales nearly linearly with the number of GPUs used. As proof of concept we reproduce the critical temperature of the 2D Ising model using finite size scaling techniques.