L（j,k）-number of Direct Product of Path and Cycle

For positive numbers j and k, an L(j,k)-labeling f of G is an assignment of numbers to vertices of G such that |f(u)-f(v)|≥j if uv∈E(G), and |f(u)-f(v)|≥k if d(u,v)=2. Then the span of f is the difference between the maximum and the minimum numbers assigned by f. The L(j,k)-number of G, denoted by λj,k(G), is the minimum span over all L(j,k)-labelings of G. In this paper, we give some results about the L(j,k)-number of the direct product of a path and a cycle for j≤k.     

固定合作规模网络的平均路径长度

本文提出了一种特殊的合作网络,称之为固定合作规模网络．我们重点研究了这类网络的平均路径长度,通过建立微分方程,得到平均路径长度的增加速度近似与网络规模的对数成正比．     

基于变长度染色体混沌遗传算法的专用交通道优化

大型运动会要求主办方在规定时间内将相关人员从运动员村运送至指定比赛场馆.基于大城市日趋严重的交通拥堵,为满足运送时间的要求,通常在城市公共交通网络中设置专用交通道.但专用交通道的设置会对城市公共交通产生影响,最小化其对城市公共交通影响是专用交通道优化问题的关键.针对此类问题,在给出了改进的混合整数规划模型的基础上,提出了基于问题特性的变长度染色体混沌遗传算法,包括变长度染色体编码、混沌个体初始化、交叉操作、变异操作、适应度函数的计算和不可行解的惩罚、修复策略等.最后,以经典算例和随机生成算例对算法有效性进行了验证.     

区域运输结构优化路径模型及算法

为寻找区域运输结构优化的最佳调整路径,运用最优控制论,构建优化模型与算法,并对珠三角客运结构优化进行实证研究.研究结果表明:所建立的优化模型精度较高,算法有效,寻找的最佳调整路径合理;可解决运输业总周转量增长率不低于一定比例的前提下,各种运输方式每年应分别以多大的增长率增长,至少需要多少年才能达到某个理想的合理结构目标.     

基于路阻函数的多任务点机动路径规划方法研究

针对复杂路网条件下,多分队多任务点行军时路线难以决策的问题,建立了同时考虑道路服务水平和分队数量的路阻函数;基于该函数的性质,提出了多任务点行军时各分队路径优化规则,构建了多任务点行军时路径规划模型;对比了部队统一机动和各分队自主行进两种规划方式的行程时间,定量说明了指挥员路径规划能力对多任务点行军的影响.为复杂路网条件下多分队、多任务点的机动指挥提供了决策方法和依据.     

给定最大度的单圈偶图的谱半径

单圈偶图是边数等于顶点数的简单连通偶图.Δ（G）表示图G的最大度.文中给出了最大度为Δ(≥ⁿ⁺¹/2)的n阶单圈偶图的谱半径的上界,并刻画了达到该上界的图.文中还证明了当Δ（G）≥[（2n+1）/3]+1时,n（≥8）阶单圈偶图G的谱半径随着最大度的递增而严格递增,并在此基础上给出了谱半径排在前17位的n（≥16）阶单圈偶图.     

椭圆中的最值问题的求法

椭圆中的最值问题是重要题型,也是高考题中的热点,解这类题不仅用到椭圆的基础知识,而且还要用求最值的方法,这类题综合强,灵活性大,学生解这类题常感困难,因而研究这类题的解法无疑是十分必要的．那么怎样解椭圆中的最值问题呢？     

无线局域网室外覆盖路径损耗计算分析及规划布局建议

介绍了无线局域网(WLAN)所用IEEE 802.11x标准的技术特点和频率特性,选择修正的COST231 HATA无线信号传播模型对信号路径损耗进行计算,以图表的形式描述了WLAN所在频段(2.4 G-Hz)的空间信道衰落特征.通过计算得出结论:随着传输距离和AP/STA天线高度差的增加,WLAN无线信道路径损耗将迅...     

Studies of super-short pulse generated by a free-electron lasers at perfect synchronism

Three-dimensional （3D） simulations and theoretical analyses on super-short pulse generated using free- electron lasers （FELs） at perfect synchronism are carried out with the help of our 3D OSIFEL code. The evolution of longitudinal pulse width in the Japan Atomic Energy Research Institute （JAERI） experiment is simulated. The results show that the optical pulse is compressed on successive passes due to the slippage between the optical and electron beams, and an ultra-short 221-fs optical pulse is finally obtained, which agrees with the experiment. Furthermore, to shorten wavelength such as soft ultraviolet （SUV） spectrum range, an ultra-short pulse generated at perfect synchronism is analyzed and studied. Finally, the relationship between the optical pulse length compressed and the peak electron beam current is calculated. It shows that the higher the electron beam current, the shorter the output FEL width length, due to the higher gain.     

Experimental validation of domain-level gradient-based and hierarchical PCE-based routing and control in heterogeneous optical networks

A domain-level gradient-based routing （DLR） algorithm for heterogeneous optical networks with syn- chronous digital hierarchy and optical transport network domains is proposed and experimentally vali- dated. This algorithm classifies domains into groups with incremental levels on the basis of domain-level partitioning, and guides paths level by level along a gradient on the basis of interdomain routing tree evolution. The proposed algorithm is implemented in the hierarchical path computation element-based control architecture for connection provisioning. Testbeds with commercial and emulated nodes are es- tablished to verify the feasibility and performance of the algorithm. Experimental and emulation results show that DLR effectively performs in terms of network blocking probability, real time characteristics, and scalability.