英标BS8110与JTJ267—1998《港口工程混凝土结构设计规范》的异同点

着重介绍英标BS8110与我国现行规范JTJ267-1998<港口工程混凝土结构设计规范>在设计理念、材料特性取值、荷载系数、荷载组合、耐久性设计要求等方面的异同点.     

RS乘积码译码算法研究

文章介绍了一种基于梯度算法的Turbo乘积码（以RS码作为分量码）的译码算法。该算法以迭代Chase-Ⅱ算法为基础,利用该算法译码得到的每行（或列）最优判决码D（m-1）来代替竞争码字C,节省了寻找C的过程,从而简化了外信息和软输出的计算。文章以RS（15,11）码为分量码进行了matlab仿真,仿真结果表明：该算法能在基本保持turbo乘积码和Chase算法译码性能基础上,提高译码速度,降低译码复杂度。     

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。     

市政污水池防腐防水涂层设计新标准

对比了《建筑与市政工程防水通用规范》（GB 55030—2022）和《地下工程防水技术规范》（GB 50108—2008）中有关污水池防水设计的区别,分析了新规范对市政污水池的防水要求,讨论了污水池防腐和防水涂层的涂装顺序,列举了常见的污水池防腐防水涂层配套。以某污水厂为例,说明了常见市政污水池的防腐防水做法,对规范实施过程中的技术问题进行探讨。     

中美规范灌注桩单桩抗压承载力计算对比

灌注桩单桩抗压承载力的计算是高桩码头及公路桥梁设计的重要组成部分。随着国内设计单位走出去的步伐逐渐加快,设计人员应快速掌握并应用不同国家的设计规范。通过对比中国的《码头结构设计规范》《公路桥涵地基与基础设计规范》和美国的《公路桥梁设计规范》,得出不同规范在灌注桩侧阻及端阻计算细节、安全系数储备等方面的异同点。依托实际工程,结合钻探地质资料,比较3种规范对应的单桩竖向抗压承载力大小,并评价各规范优缺点。结果表明,两个中国规范操作相对简单但遇到特殊土质时受限,美国规范概念明确且适用范围更广,但计算过程相对复杂。     

中欧规范关于重力式码头地基承载力计算方法的对比

针对欧洲规范体系和中国规范体系中重力式码头地基承载力计算方法不同的问题,通过对两套规范体系的设计方法和计算模型对比和分析,并结合某工程实例计算排水情况下的地基承载力,结果表明二者存在明显差异。欧洲规范通过荷载分项系数反映了荷载的不确定性;中国规范则在地基承载力计算时考虑竖向应力和地基承载力竖向应力的关系,计算结果介于欧标设计方法 1两种组合的结果之间。用欧洲规范英国国家附录进行设计时须验算两种组合方法,计算重力式码头地基承载力时还应注意计算面的选取。     

“雪龙2”号舱底水系统的设计

以"雪龙2"号为例,基于中国船级社钢质海船入级规范、特种用途船规范和SOLAS,对特种用途船舶舱底水系统设计进行研究,并对一系列技术关键点进行了探讨,如舱底水管径计算、舱底泵布置、舱底水仓容积计算和综合舱底水系统等。对需关注的问题进行讨论和分析,得出相关结论,对特种用途船舱底水系统设计具有一定的指导意义。     

PREDICTION OF WELDING DEFORMATIONS BY FEM BASED ON INHERENT STRAINS

IntroductionIt is of importance to predict and control theresidual deformations caused by welding pro-cesses to ensure the accuracy of a welded produc-tion.Nowadays there are three ways to deter-mine the welding deformations:( 1 ) empiricalformulas or curves based on the experiments;( 2 ) thermo- elasto- plastic analysis by FEM;( 3)inherent strain method.The empirical formulasare only suited to the cases of simple plates orbeams that undergo a welding cycle close to theexperiment conditions. …     

SOFT COMPUTING APPROACH FOR NOISY IMAGE RESTORATION

IntroductionSoftcomputing is a consortium of different com-puting tools to deal with real world problems ef-ficiently.The aim of softcomputing is to exploitthe tolerance for imprecision and uncertainty toachieve tractability,robustness and low cost[1] .Neurocomputing is one of the major componentsof soft computing,the other two important con-stituents are fuzzy logic and probabilistic reason-ing,which subsumes belief networks,geneticalgorithms and chaotic systems.Often,to solvea fairly complex…     

MERGING AND SPLITTING SECOND-ORDER SELF-SIMILAR PROCESSES (TRAFFICS)

Recent traffic measurements in corporate LANs, Variable-Bit-Rate (VBR) video sources, ISDN control channels, and other communication systems, have indicated traffic behavior of self-similar nature, which has implications for design, control and analysis of high-speed networks. Merging and splitting are two basic networking operations. This paper gave the necessary and sufficient conditions for that merging of second-order self-similar traffic streams also results in a second-order self-similar stream. It shows that splitting traffic streams of the second-order self-similar stream are still self-similar streams by the independent splitting operation.