An efficient parallel algorithm for shortest paths in planar layered digraphs

This paper presents an efficient parallel algorithm for the shortest path problem in planar layered digraphs that runs in O(log3n) time with n processors. The algorithms uses a divide and conquer approach and is based on the novel idea of a one-way separator, which has the property that any directed path can be crossed only once.     

An efficient parallel algorithm for shortest paths in planar layered digraphs

INTRODUCTION Computing shortest paths in directed graphs isa fundamental optimization problem with applica-tions to many areas of computer sciences and op-eration research (Bellman, 1958; Coremen, 1990;Cohen, 1993). Given a digraph G with non-negativeweights on its edges and two vertices s and t of G,the single-pair shortest path problem consists ofdetermining a directed path from s to t with mini-mum total weight. Among the well-known sequential algorithmsfor this problem is the classic…     

GRIN光学中光线追迹的一种新方法

由Hamilton光学中的Lagrange方程推出光线方程，用Runge-Kutta方法求解光线方程，给出光线追迹的新方法。     

浅析渤海大学图书馆中文期刊回溯建库工作

分析了中文文献回溯建库的必要性,介绍了渤海大学图书馆中文书目数据库建设现状,阐述了在回溯建库过程中遇到的问题及解决方案。     

预测摄动平面非Hamilton系统混沌的解析方法

An analytical method for predicting chaos in perturbed planar non-Hamiltonian integrable systems with slowly varying parameters was developed.Based on the analysis of the geometric structure of unperturbed systems.the condition of transversely homoclinic intersection was given.The generalized Melnikov function of the perturbed system was fund by applying the theorem on the differentiability of ordinary differential equation solutions with respect to parameters.     

一种改进的二次曲线轮廓度误差的评定方法

提出了一种改进的二次曲线轮廓度误差的评定方法。以最小二乘曲线的焦点坐标作为中心划分正方形网格,在其中按一定规则设定标志点,若标志点配对拟合曲线计算所得轮廓度误差过大就将其剔除。然后在误差较小的区域进一步细分网格并配对拟合曲线,再以多次迭代运算的方法最终求得最小条件法下的轮廓度误差值。该方法搜索速度快,计算精度高,适用于任意平面二次曲线的轮廓度误差评定,辅以MATLAB软件实现误差求解的可视化,最后实例证明该算法的可靠性。     

An efficient method for parallel CRC automatic generation

INTRODUCTIONCRC (CyclicRedundancyChecking)codesarewidelyusedintelecommunication ,especiallyintheinternallayersofprotocolssuchasEther net,X2 5,FDDIandATM (AAL5) .Thecom monhardwaresolutionforCRCcalculationisthelinearfeedbackshiftregister (LFSR) ,charac ter…     

An efficient method for parallel CRC automatic generation

The State Transition Equation (STE) based method to automatically generate the parallel CRC circuits for any generator polynomial or required amount of parallelism is presented. The parallel CRC circuit so generated is partially optimized before being fed to synthesis tools and works properly in our LAN transceiver. Compared with the cascading method, the proposed method gives better timing results and significantly reduces the synthesis time, in particular. Project (No. 60271010) supported by the National Natural Science Foundation of China     

Implicit iterative method for III-posed equations with perturbed operators and data

In this paper, the author applied an implicit iterative method to solve linear ill-posed equations with both perturbed operators and perturbed data. After having carefully estimated some terms involved, a satisfactory order of convergence rate was derived. Supported by the National Natural Science Foundation of China (19671050)     

数控加工编程时由数学方程描述的非圆曲线的一种逼近方法

本介绍了一种在数控加工编程中由数学方程描述的非圆曲线的一种逼近方法,并以抛物线为例给出了计算机辅助编程的节点坐标计算程序。     

多约束非线性背包问题的一种有效算法

1IntroductionWe consider the following multi-di mensional nonlin-ear knapsack problem(MNKP)maxf(x)=∑nj=1fj(xj)s.t.gi(x)=∑nj=1gij(xj)≤bi,i=1,…,m,x∈X={x|lj≤xj≤uj,xjinteger,j=1,…,n},where allfjand allgijare nondecreasing functions ofxjon[lj,uj]forj=1,…,n,i=1,…,m,andljandujare integer lower and upper bounds forxj,re-spectively,j=1,…,n.It has been proved that0-1linear knapsack problemis NP-hard[1].Nonlinear knapsack problems have numerous appli-cations in various fields,for example,ca…     

An efficient numerical shape analysis for light weight membrane structures

The determination of initial equilibrium shapes is a common problem in research work and engineering applications related to membrane structures. Using a general structural analysis framework of the finite particle method （FPM）, this paper presents the first application of the FPM and a recently-developed membrane model to the shape analysis of light weight mem- branes. The FPM is rooted in vector mechanics and physical viewpoints. It discretizes the analyzed domain into a group of parti- cles linked by elements, and the motion of the free particles is directly described by Newton＇s second law while the constrained ones follow the prescribed paths. An efficient physical modeling procedure of handling geometric nonlinearity has been developed to evaluate the particle interaction forces. To achieve the equilibrium shape as fast as possible, an integral-form, explicit time integration scheme has been proposed for solving the equation of motion. The equilibrium shape can be obtained naturally without nonlinear iterative correction and global stiffness matrix integration. Two classical curved surfaces of tension membranes pro- duced under the uniform-stress condition are presented to verify the accuracy and efficiency of the proposed method.     

基于NURBS模型的自由曲线加工轨迹自适应生成方法(英文)

为实现NURBS曲面快速高精度实时差补,提出了基于修正型sigmoid函数的动力学模型,给出了最大速度、弓高误差、加工曲线的曲率半径和插补周期之间的约束条件.该模型在满足jerk、加速度、速度均连续的前提下,将常用的三次多项式S型以及三角多项式S型动力学模型的15个分段数减少至3个.在此基础上,提出采用差商代替导数的优化Adams算法,避免了常用的Taylor展开所遇到的高阶求导计算,求取了差补周期参数.最后通过减少低次零值B样条基函数的计算,对De Boor-Cox递推算法进行了简化设计,提出了精简型De Boor-Cox算法,缩减了计算量.仿真分析表明,所提算法可根据加工路径有效控制进给速度,在保证加工精度的同时,使计算量得到减少,提高了运算速度.实验结果显示本加工方法可以正确计算目标参数,并适合应用于实际加工系统.     

An inexact parameterized newton method for B-differentiable equations

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基于信息熵的评价筛选方法

在线评价系统已经被广泛地应用于各在线交易中,用来对卖家提供的服务作出好或坏的评价。但功能会受到一些不公平评价等问题的影响。基于信息熵的评价筛选方法则可以解决此类不公平评价的问题。文章在贝叶斯评价系统的框架上讨论了基于信息熵的评价筛选方法,并以实验验证其有效性,最后指出了其不足之处。     

无损检测信号快速三维有限元模拟的组合方法

提出了一种基于三维有限元的电磁无损检测缺损响应快速模拟的组合方法, 该方法由三项技术构成, 分别是局部计算技术、差场技术和迭代解技术. 采用局部计算技术, 可以将三维计算区域限制在缺损附近的一个较小范围; 使用差场技术, 无缺损情形下的轴对称解可以用来简化三维网格生成以及快速获得三维解答; 而应用迭代解技术, 可以加速无损探头信号有限元模拟的矩阵方程求解. 实例计算表明本文方法是正确有效的, 可以节省大量的计算机资源.     

浑浊易沉淀液体样品总有机碳测定方法

改良了一种针对浑浊易沉淀液体的总有机碳(TOC)检测方法(固体NPOC法),并验证了该方法的可靠性与准确性,优化了该方法中样品的预处理过程,通过实际样品进一步验证了该方法检测浑浊易沉淀液体样品TOC的准确性。结果表明:此方法与标准液体的NPOC法均可用于可溶性葡萄糖溶液的TOC测定,其准确度无显著性差异(P0.05);但测定浑浊易沉淀的不溶性淀粉标准溶液时,液体NPOC法所测定的值明显小于标准值和固体NPOC法的测定结果,且淀粉浓度越大,差异越明显;对样品进行盐酸酸化,其pH值低于4即可,总进样体积以200μL或300μL为佳。     

基于MPRP方法的求解单调非线性方程组的算法

MPRP方法是求解优化问题的一种共轭梯度算法,将其推广至求解单调非线性方程组,给出收敛性的证明,并通过数值实验表明算法是稳定和有效的。     

基于有限元法的双衬层危险废物填埋场高压直流电渗漏检测

According to the structural characteristics of hazardous waste landfill,a new model based on the finite element method(FEM)is developed.The detection layer is considered as a sealed space and it is assumed that total current flows through the leak for the high resistivity of geomembrane liner.The leak current is regarded as a positive point current I and the other current source is-I.Electrical potential of an arbitrary point in detection layer satisfies Poisson equation. Experiments for detecting leaks in liner were carried out.Excellent agreement between experimental data and simulated model data validates the new model.Parametric curves for a single leak show that with optimum selection of field survey parameters leaks can be detected effectively.For multiple leaks,the simulated results indicate that they are detectable when leak separation is larger than measurement spacing.     

Science Letters：Evaluation of a kinetic uricase method for serum uric acid assay by predicting background absorbance of uricase reaction solution with an integrated method

A patented kinetic uricase method was evaluated for serum uric acid assay. Initial absorbance of the reaction mixture before uricase action （A0） was obtained by correcting the absorbance at 293 nm measured before the addition of uricase solution, and background absorbance （Ab） was predicted by an integrated method. Uric acid concentration in reaction solution was calculated from AA, the difference between A0 and Ab, using the absorptivity preset for uric acid. This kinetic uricase method exhibited CV〈4.3% and recovery of 100%. Lipids, bilirubin, hemoglobin, ascorbic acid, reduced glutathione and xanthine 〈0.32 mmol/L in serum had no significant effects. △A linearly responded to 1.2 to 37.5 μmol/L uric acid in reaction solution containing 15 μl serum. The slope of linear response was consistent with the absorptivity preset for uric acid while the intercept was consistent with that for serum alone. Uric acid concentrations in clinic sera by different uricase methods positively correlated to each other. By Bland-Altman analysis, this kinetic uricase method accorded with that by quantifying the total change of UV absorbance on the completion of uricase reaction. These results demonstrated that this kinetic uricase method is reliable for serum uric acid assay with enhanced resistance to both xanthine and other common errors, wider range of linear response and much lower cost.