On the Detection of Visual Features from Digital Curves Using a Metaheuristic Approach

In computational shape analysis a crucial step consists in extracting meaningful features from digital curves. Dominant points are those points with curvature extreme on the curve that can suitably describe the curve both for visual perception and for recognition. Many approaches have been developed for detecting dominant points. In this paper we present a novel method that combines the dominant point detection and the ant colony optimization search. The method is inspired by the ant colony search (ACS) suggested by Yin in [1] but it results in a much more efficient and effective approximation algorithm. The excellent results have been compared both to works using an optimal search approach and to works based on exact approximation strategy.

基于MFC的MapInfo数字地图在VC++中的集成

介绍了Mapinfo提供的与其他程序连接,进行二次开发的方法。并以OLE自动化技术为例,详细介绍了在VC++环境中,利用MFC对OLE自动化技术的支持,Mapinfo数字地图在VC++中的具体实现过程。

利用MFC进行高速公路平面曲线设计

论述了选用ＭＦＣ开发平台作为高速公路平面曲线设计的原因，介绍了平面曲线直线段、缓和曲线和圆曲线的数学模型并以此模型为基础，利用ＭＦＣ的编程技术实现了平面曲线的计算与图形绘制，并按照ＯＤＢＣ技术实现应用程序与数据库的通讯图２。

基于MOSS和MFC的宇航任务周计划交互技术

以数控加工为主的生产车间为例,提出了一种基于MOSS和MFC的周计划交互技术。通过搭建项目网站和开发辅助应用程序等数字化技术,实现了周计划快速准确的编制、下达和反馈,构建了生产调度和操作者之间沟通的桥梁,使生产计划无纸化和透明化。

Optimal Polygonal Approximation of Digital Planar Curves Using Genetic Algorithm and Tabu Search

Three heuristic algorithms for optimal polygonal approximation of digital planar curves is presented. With Genetic Algorithm (GA), improved Genetic Algorithm (IGA) based on Pareto optimal solution and Tabu Search (TS), a near optimal polygonal approximation was obtained. Compared to the famous Teh chin algorithm, our algorithms have obtained the approximated polygons with less number of vertices and less approximation error. Compared to the dynamic programming algorithm, the processing time of our algorithms are much less expensive.

Sensitive Information Security Based on Elliptic Curves

The elliptic curve cryptography algorithm represents a major advancement in the field of computer security. This innovative algorithm uses elliptic curves to encrypt and secure data, providing an exceptional level of security while optimizing the efficiency of computer resources. This study focuses on how elliptic curves cryptography helps to protect sensitive data. Text is encrypted using the elliptic curve technique because it provides great security with a smaller key on devices with limited resources, such as mobile phones. The elliptic curves cryptography of this study is better than using a 256-bit RSA key. To achieve equivalent protection by using the elliptic curves cryptography, several Python libraries such as cryptography, pycryptodome, pyQt5, secp256k1, etc. were used. These technologies are used to develop a software based on elliptic curves. If built, the software helps to encrypt and decrypt data such as a text messages and it offers the authentication for the communication.

A New Digital Multilevel Proxy Signature Scheme Based on Elliptic Curve Cryptography

Based on the analysis of elliptic curve digital signature algorithm（ECDSA）,aiming at multilevel proxy signature in which the original signer delegates the digital signature authority to several proxies and its security demands, a new multilevel proxy signature scheme based on elliptic curve discrete logarithm problem （ECDLP） is presented and its security are proved.

Error Model of Curves in GIS and Digitization Experiment

A stochastic error process of curves is proposed as the error model to describe the errors of curves in GIS. In terms of the stochastic process, four characteristics concerning the local error of curves, namely, mean error function, standard error function, absolute error function, and the correlation function of errors , are put forward. The total error of a curve is expressed by a mean square integral of the stochastic error process. The probabilistic meanings and geometric meanings of the characteristics mentioned above are also discussed. A scan digitization experiment is designed to check the efficiency of the model. In the experiment, a piece of contour line is digitized for more than 100 times and lots of sample functions are derived from the experiment. Finally, all the error characteristics are estimated on the basis of sample functions. The experiment results show that the systematic error in digitized map data is not negligible, and the errors of points on curves are chiefly dependent on the curvature and the concavity of the curves.

Diameter Measurements of the Upper Parts of Trees Using an Ultra-Telephoto Digital Photography System

We develop a new technique to measure the exact upper diameters of trees that is comparatively simple and inexpensive. We can measure the diameters of entire tree trunks efficiently and with high precision. The system uses a digital camera with a ~15 - 30× telephoto lens to take a photograph that can be used for measuring the diameter of the upper part of a comparatively slender tree trunk. Since this method requires a measuring distance and the height of the target point in the image, a range finder capable of measuring angles was combined with the main digiscoping system. A range finder sensor uses a laser and makes a 360 degree angle of observation possible. The diameter of a target position of the objective tree can be obtained by measuring the digital image using image editing software and calculations from spreadsheet software. We focus on the Japanese cedar species in the southwestern part of Japan. Photographic measurements were obtained prior to thinning. The estimates that we obtained largely agree with the true measurements of all trees. With regard to the estimated accuracy of all measured trees, the maximum error ratio was 7.0% (1.45 cm), with a ~2% - 4% error for most of the estimated results. Although the absolute value of the estimation error was 1.87 cm (5.3%) at the maximum (9.87 m in height and 35.5 cm in diameter), an estimation accuracy of <1 cm was reproduced in almost all measurements except for the extreme hypertrophy portion by butt swelling.

A Secure Hardware Implementation for Elliptic Curve Digital Signature Algorithm

Since the end of the 1990s,cryptosystems implemented on smart cards have had to deal with two main categories of attacks:side-channel attacks and fault injection attacks.Countermeasures have been developed and validated against these two types of attacks,taking into account a well-defined attacker model.This work focuses on small vulnerabilities and countermeasures related to the Elliptic Curve Digital Signature Algorithm(ECDSA)algorithm.The work done in this paper focuses on protecting the ECDSA algorithm against fault-injection attacks.More precisely,we are interested in the countermeasures of scalar multiplication in the body of the elliptic curves to protect against attacks concerning only a few bits of secret may be sufficient to recover the private key.ECDSA can be implemented in different ways,in software or via dedicated hardware or a mix of both.Many different architectures are therefore possible to implement an ECDSA-based system.For this reason,this work focuses mainly on the hardware implementation of the digital signature ECDSA.In addition,the proposed ECDSA architecture with and without fault detection for the scalar multiplication have been implemented on Xilinxfield programmable gate arrays(FPGA)platform(Virtex-5).Our implementation results have been compared and discussed.Our area,frequency,area overhead and frequency degradation have been compared and it is shown that the proposed architecture of ECDSA with fault detection for the scalar multiplication allows a trade-off between the hardware overhead and the security of the ECDSA.

基于区块链的城市智能交通网络均衡分配方法

为了提高城市智能交通网络的应用效率,有效分配网络中存在的资源,同时保证网络资源分配的均衡度。因此,提出区块链技术下城市智能交通网络均衡分配方法。通过建立城市智能交通网络模型,分析用户在交通网络中的资源需求。根据用户的需求,采用区块链技术分配网络中的资源,通过引入椭圆曲线数字签名算法,对需求和资源的发布信息加密处理,并根据资源需求与资源供应之间的匹配,完成城市智能交通网络资源的均衡分配。实验结果表明,所提方法的用户吞吐率高,且Jain公平指数在0.8以上,表明所提方法的资源分配合理性高。

城市曲线钢-混凝土组合梁智能建造的探索

城市曲线钢-混凝土组合梁的智能建造,是将智能技术与桥梁工程建设技术相结合,实现建造技术的数字化赋能。为落实碳达峰碳中和目标任务,推动城乡建设绿色发展,加大智能建造在工程建设各环节应用。本文立足于探索分析城市曲线钢-混凝土组合匝道桥和立交桥的数字设计、智能生产、智能施工,智能检测及运维现状,为曲线钢-混凝土组合梁全链条智能建造与运维的发展提供技术与理论参考。

基于数据加密的传感器网络信息安全架构设计

为了实现传感器数据的安全传输,基于椭圆曲线加密算法,设计传感器网络信息安全架构。架构分为传感器层、中段聚合器和顶层聚合器。传感器层完成数据检测、数据加密和数字签字,椭圆曲线倍点运算交由外包服务器进行运算;中段聚合器对发送者、接收者、时间戳和数字签名进行验证,验证通过后,对所辖传感器的数据进行聚合,并完成数字签名,上传顶层聚合器;顶层聚合器对发送者、接收者、时间戳和数字签名进行验证,验证通过后,利用密钥对密文进行解密,得到传感器检测数据。系统测试结果表明,传感器层外包倍点运算可以显著提高运算效率;中段聚合器和顶层聚合器均具有较高运行效率。

EH36钢焊接接头焊趾处应力集中对高低周复合疲劳的影响

为研究船舶结构用钢EH36钢焊接接头焊趾处应力集中对高低周复合疲劳的影响,对不同焊缝形貌20 mm厚EH36钢双面全熔透对接接头进行高低周复合疲劳试验.研究发现,高低周复合疲劳对接头寿命的降低幅度随着高周应力比的增大而增大;结合数字图像相关法测量结果分析,发现焊趾处应力集中系数越大,接头的高低周复合疲劳寿命越低,其降低幅度随着高周应力比的增大而增大.基于试验数据对模型进行验证,结果表明,应力集中系数高的接头疲劳寿命低且寿命预测结果分散性增大;Palmgren-Miner模型和Zhu模型由于未充分考虑高低周耦合损伤作用,导致寿命预测结果相对危险.修正后Zhu模型在充分考虑低周疲劳对高低周复合疲劳寿命的影响后,预测寿命大于实际寿命的预测点较少,预测结果相对安全,且分散性较小,误差也较小.

数字技术与价值链长度:延伸还是缩短?

本文基于2000—2018年经济合作与发展组织国家间投入产出表和对外经济贸易大学全球价值链指标数据库,实证研究数字技术和价值链长度之间的关系。研究发现,数字技术与价值链长度之间呈倒U型关系,即发展初期数字技术有滞后效应,随后带来价值链的延伸,当发展体量过大时,发展失调又带来价值链缩短。创新水平和人力资本水平对价值链长度起正向促进作用,数字技术通过创新水平和人力资本水平的倒U型关系影响价值链长度。同时,由于不同行业特征以及不同价值链类型差别,数字技术对价值链长度的影响还具有异质性。调节效应表明,作为数字技术应用和发展的高质量体现和成果展示,产业智能化对数字技术与价值链长度的倒U型关系也起正向调节作用,产业智能化水平较高时,曲线会变得陡峭且拐点推迟出现,进而促进数字技术的高质量发展,这有助于全球价值链的进一步发展。

基于二阶链式子区的金属拉伸试验DIC辅助测试方法

为提高金属材性试验的测量精度和测试效率,在传统拉伸试验方法的基础上引入数字图像相关(Digital Image Correlation, DIC)技术,提出相应形变测量理论及方法。基于拉伸试件的颈缩变形特征,提出链式形变测量理论,该理论通过一种跟随表面形状变化而自由变形的柔性链条来表征各阶段的试件形变。进一步通过设置多个连续且等尺寸的DIC二阶链式子区,采用DIC亚像素算法得到任意变形时刻的链式子区角点坐标,并进一步得到沿试件长度方向的柔性离散链形变结果,实现对试件各处应变、颈缩极值点等的求解,从而建立了一套完整的金属拉伸试验DIC辅助测试方法。开展了多个标准金属试件的拉伸试验,通过与引伸仪、靶标图像测量等传统方法对比,验证了该文方法对颈缩效应、弹性模量、极限伸长率、真实应力-应变曲线等金属材性指标具备较高测量精度及有效性,同时该文方法能够实现高度自动化测量,可在金属拉伸试验领域进行工业化推广普及。

数字经济的节能减排效应及作用机制——基于空间关联网络溢出模式

本文将数字经济、能源强度和碳排放强度三者置于统一框架,构建数字经济空间关联网络权重矩阵,利用空间杜宾模型检验发现:数字经济对能源强度和碳排放强度的影响均呈现倒“N”型特征,具有显著的空间溢出效应,数字经济发展到一定阶段可以实现“节能”与“减排”双赢。数字产业化和产业数字化双重维度的检验发现,数字产业化通过数字产业在地区间的布局和对要素吸引力改变产业集聚程度影响碳排放强度;产业数字化通过数字技术嵌入各个行业,改善资源配置效率和能源利用效率,通过能源强度影响碳排放强度。本文为数字经济政策制定和实现“双碳”目标提供了启示。

区块链环境下的预制菜溯源研究

提出一种基于以太坊智能合约的预制菜溯源模型。分析当前预制菜存在的问题,如食品安全性难以保证、没有统一标准和食品出现问题难溯源的情况。通过区块链去中心化、不可篡改和可溯源等特点实现基于以太坊的预制菜溯源模型。模型规定每个环节负责人都需对自身负责的环节项目进行数字签名,从而确保出现问题时的责任划分。同时,为减少在以太坊的存储开销,设计一种基于IPFS(inter planetary file system)和默克尔树的存储机制。实验结果表明:模型能够在正常开销范围内实现预制菜全流程,同时,模型在以太坊的存储开销低于直接存储,具备一定优越性。

基于GAS算法的卵砾石粒径自动识别应用研究

粒径和级配是表征床面组成的重要指标,基于GAS粒径自动识别技术可自动识别粗粒床面粒径并生成级配曲线,能够大幅提高现场采样和分析的效率。为了验证GAS的分割效果,采用GAS提供的默认参数进行分割,同时应用ImageJ软件手动分割进行验证。结果表明:GAS级配曲线的相对误差为5.7%,相关系数为0.992。另外,采用单参数和多参数敏感性分析法来标准化参数调整方案,gre、can1和can2对GAS提取的级配曲线和特征粒径有显著影响,其中gre起主导作用,而can1和can2控制着砾石边界的检测完整性。