Algorithm for Network Delay Estimation Based on End-to-End Data Moment

现有时延层析算法大多考虑离散时延模式,但算法效率比较低。为此,提出一种连续时延估计算法,假定链路时延为某参数的函数分布,根据多播特征并基于端到端数据的矩,利用非线性最小二乘法估计链路时延分布函数的参数,并在每步迭代中用一维牛顿搜索确定最优步长,达到快速收敛。应用MATlAb和nS2仿真软件得到的数据表明,该算法所需的存储量少,算法简单且效率较高。The up-to-date algorithms on delay tomography are based on the discrete delay mode,but it is low efficiency in this mode.This paper proposes a continuous delay mode,whose delay is distributed on a function with some parameters.According to the rule of multicast and based on end-to-end moments,the parameters can be estimated using nonlinear least squares and the best step is chosen by the one-dimension Newton search in iteration.Experimental results on Matlab and NS2 simulation show that the algorithm needs little storage and is simple with high efficiency.国家自然科学基金资助项目(41074077;40774065

颅内原发恶性淋巴瘤的MRI诊断(附12例报告)

目的　探讨颅内原发恶性淋巴瘤CT及MR的表现特征 ,以提高诊断准确率。方法　对 12例经手术病理证实的颅内原发恶性淋巴瘤的CT及MR表现进行回顾分析。结果　共检出 3 2个病灶 ,其中单发 9例 ,分别位于额、颞、顶叶深部脑白质 8例 ,位于颞叶表面 1例 ;多发 3例 ,病灶多位于深部脑白质。CT多表现为圆形或类圆形稍高密度灶 ,MRI表现为T1WI低或等信号 ,T2 WI为稍低信号。多数病灶周围有轻 -中度高信号水肿带 ,病灶边界尚清楚。增强扫描见所有病灶均有强化 ,2 3个 ( 72 .0 % )病灶呈均匀强化 ,18个 ( 5 6.2 5 % )病灶强化后出现缺口或凹陷改变。病理结果 :11例为非何杰金氏淋巴瘤 ,1例为浆细胞淋巴瘤。结论　尽管颅内原发恶性淋巴瘤的影像表现与其它颅内肿瘤如脑膜瘤、胶质瘤及转移瘤等有许多相似之处 ,但通过认真分析其影像特征 ,术前的正确诊断是有可能

基于悬置刚度法的客车方向盘怠速振动传递路径分析

为更加准确识别某中型客车怠速工况下的方向盘振动来源,提升传递路径分析精度,文中总结了基于悬置刚度法分析振动传递路径的基本方法,并以该车方向盘为研究对象开展方法验证。首先,通过计算该车悬置软垫预载力、对已有的悬置软垫数据进行多元回归拟合以及整车方向动刚度转化计算出该悬置软垫实际动刚度;其次,测试系统水平频响函数以及激励点与响应点的加速度信号;再次,用基于阻抗矩阵法TPA所得的结果以及实测结果作为标杆进行对比,比较结果显示悬置刚度法TPA具有较高的精度。传递路径分析结果表明排气系统X向振动对方向盘怠速振动贡献量最大。断开发动机与排气系统连接,发现方向盘怠速振动加速度明显降低,进一步验证了基于悬置刚度法的传递路径分析结果的可靠性。上述分析结果可为车内振动的传递路径分析提供借鉴。厦门市科技重大平台资助项目(3502Z20151002

A Parallel Algorithm for Fresnel Tomography

摘要:与射线层析成像相比, Fresnel 层析成像考虑波频率的影响, 具有较高的分辨率,但所需的存储 空间和计算量更大,因此提出了Fresnel 层析成像的并行算法1 把大型层析反演方程组的求解,转化成 对其中的各个方程进行相互独立的计算,避免了大型系数矩阵的存储问题;把一个Fresnel 带的正演和 反演计算放在一个进程,不同Fresnel 带的计算相互独立进行,不需要信息传递,达到了极高的并行度; 从进程之间没有通信, 仅当从进程计算结束后,在主进程与各从进程之间有少量的数据传递,使通信开 销达到了极小的程度1 应用MPI 在Linux PC 集群环境下实现了该算法,实际测试表明,该算法具有较 高的并行度和加速比.Abstract 　In cont rast with ray2based t raveltime tomography , Fresnel tomography account s for the band2 limited nature of seismic waves and gives the higher resolution tomograms1 Because Fresnel tomography demands much computer memory and much running time , a parallel algorithm for it is proposed1 The tomographic inversion is t ransformed to resolving respectively a series of single equation in light of backprojection principle , each equation corresponding to a Fresnel zone1 The forward and inverse computation concerning a Fresnel zone is allocated to one process and is independent of other processes1 Then the storage and calculation of the large2scale mat rix in the tomography are avoided1 No message delivers between the slave processes , and only a little of data delivers between a master process and the slave ones1 By using the portable message passing interface standard (MPI ) for the communication , the computing code of the algorithm is implemented on Linux system , which allows to dist ribute the work on several PCs connected via standard Ethernet in an in2house network , and greatly expands the applicability of Fresnel tomography1 The test s on the synthetic and observed seismic t ravel time data show that this parallel algorithm has a good performance on Linux PCs1基金项目:国家自然科学基金项目(40774065) ;福建省自然科学基金项目(2006J0044

インクルーシブ体育に向けた中学校武道授業の合理的配慮に関する検討 ― 中学校武道専門教員への聞き取り調査から ―

Japan ratified the Convention on the Rights of Persons with Disabilities in 2014. It was shown the necessity of striving for offer of reasonable accommodations was shown towards construction of an inclusive education system which both the children with disorders and the children without disorders study together. In this research, the interview to the Budo special teachers of a junior high school was tried for the purpose of considering reasonable accommodations concretely about the actual condition and accommodations of the student who shows difficulty in a junior high school Budo lesson. It seemed that moreover, the teacher felt dilemma for offering individual accommodations in instruction of a class

教職課程（保健体育）専攻学生の剣道に対する意識 ― 剣道経験の違いによる意識の実態と変化 ―

Through the execution of a survey research (32 questions), this study aims to reveal how students majoring in teacher-training (health and physical education) perceive Kendo, whether a different experience in Kendo leads to disparity in consciousness, and the change in consciousness before and after Kendo lessons. Results show that discrepancies in consciousness due to different experiences in Kendo were found in 9 sections of questions regarding“ whether Kendo is sport or martial arts”,“ Kendo rules”, and“ safety” before lesson. At the same time, differences in attitude were also observed in 9 other sections of questions regarding “popularization measure” and “interest” after lesson. Furthermore, just as some disparities in consciousness due to different experiences in Kendo disappeared after lesson, new disparities also emerged. These founding suggest that consciousness toward Kendo among students and the change in that consciousness do differ according to their own individual experience in Kendo; thus, students need to set separate learning objectives to match their level of experience in Kendo

A DDA Calculation on the Optical Properties of Silver Nanorods

【中文文摘】利用离散偶极近似 (Discretedipoleapproximation ,简称DDA)的方法 ,从理论上对粒子的形状、尺寸及周围介质等因素对银纳米粒子 ,特别是银纳米棒的光学性质的影响进行了较系统的研究 .计算表明 ,置于空气中的棒状银纳米粒子的光学性质与其形状密切相关 ,纵向表面等离子体共振吸收峰的位置随纳米棒长径比的增加呈现线性红移关系 .给出了空气中银纳米棒纵向表面等离子体共振吸收峰的位置随长径比变化的DDA拟合公式 .如果将金属纳米粒子置于折射率更高的介电环境中 ,其纵向等离子体共振吸收峰的位置进一步呈现线性红移关系 .合成的银纳米粒子的TEM图像及相关的UV VIS消光光谱显示DDA计算结果与实验值相当一致 .DDA算法与Mie′s理论在计算球状银纳米粒子的消光系数时给出很接近的结果 ,这表明用DDA的方法来分析银的光学性质是准确可靠的 ;而DDA算法对银纳米棒消光特性的成功拟合则表明 ,该算法相对Gans′理论而言 ,在研究纳米粒子的光学性质时具有更广的适用性及更高的准确性 . 【英文文摘】The optical properties of metal nanoparticles are quite different from those of the bulk materials mainly due to the collective oscillations of their conduction electrons known as the surface plasmon resonance (SPR), which is strongly dependent on the particle shape and size, and the dielectric properties of the local environment where the nanoparticles are embedded in. Based on the discrete dipole approximation (DDA) method, we studied the optical properties of silver nanorods with different aspect ratios ...Project supported by the National Natural Science Foundation of China (2 0 2 2 80 2 0,2 0 0 2 10 0 2

Surface-enhanced Raman Spectroscopic Study of Gold Nanoparticles with Different Shapes

【中文文摘】使用514 5nm激光激发,第一次得到了不同形状金纳米粒子的表面增强拉曼光谱(SERS)。一般情况下,较短波长(600nm)的激发。然而,对特殊形状的自组装金纳米粒子,由于避雷针效应,即使使用绿光激发也可获得很高增强的SERS。 【英文文摘】In this communication, we obtained for the first time the SERS spectra of gold at the laser excitation of 514.5 nm by fabricating the ordered array of gold nanoparticles with special shapes, e.g., sphere, tadpole, and pearlchain. Selfassemble method of these gold nanoparticles is briefly introduced. In general, the enhancement of gold by the laser excitation of short wavelength (600 nm) becuase that the coupling between conduction electrons and interband electronic transitions by using 514. 5 nm depresses the quality of the surface plasmon resonance of gold metals considerably. Our observation reveals that the SERS of self2assembly gold nanoparticles with special shape can be rather high even using the green light excitation , which is mainly due to the lightning2rod effect.国家自然科学基金创新群体研究资助项目(20021002);; 国家自然科学基金九五重点项目(29833060

Advances in Cyanobacterial Phycobilisome Assembling in vitro

光合作用的第一步是高效地捕获和传递光能.藻胆体位于蓝藻和红藻细胞的类囊体膜外朝向基质一侧,结构上主要由藻胆蛋白和连接蛋白构成,且功能上以不低于98%的效率捕获和传递光能至PSⅡ.3种类型的藻胆蛋白单体的结构类似,由于含有不同数目和种类的色素分子以及藻胆蛋白结构的细微差别导致光能最大吸收波长不同.藻胆蛋白以不同寡聚形式,加上连接蛋白的作用,依靠氢键和极性相互作用,自发组装为高度有序的完整藻胆体结构.科学家尝试体外合成和组装藻胆体,但目前只达到三聚体形式,六聚体及更高级组装远未解决.本文主要从生物组合合成的角度,综述了体外从头合成和组装完整藻胆体的历程和进展,并展望了迄今完成的最高级别的重组别藻蓝..

The Size and Shape Effects on the Optical Properties of Gold Nanoparticles

【中文文摘】纳米尺度的金属及半导体呈现出特殊的光学、电学及磁学性质,采用近年发展起来的离散偶极近似(DDA)的方法,我们分析了金纳米粒子的尺寸及形状对其光学性质的影响。粒子周围介质的影响在文中亦作了分析。计算结果显示,金纳米粒子的等离子体吸收带同时受到粒子尺寸和形状的影响,但来自形状的影响更为明显。与米氏理论及扩展的甘氏理论相比较,DDA方法在粒子尺寸不再远小于入射光波长的时候更准确,并能应用于任何形状的纳米粒子。理论计算与实验结果能较好的吻合。 【英文文摘】Metals and semiconductors exhibit unusual optical, electronic, and magnetic properties at the nanometer scale. Based on the newly developed method, discrete dipole approximation (DDA), the dependence of the optical properties of the gold nanoparticles on the size and shape was analyzed. The effects of the surrounding medium were also taken into consideration in the calculation. The calculated results show that the plasmon absorption band depends on both the size and shape of the gold noanoparticles. However , the influence of the shape is more significant . Compared to the Mieps theory and the extension , Gansp theory , the DDA method is more accurate when the dimensions of the particles are not much smaller than the wavelength of the incident light and can be applied to particles of any shape. The theoretical results are in good agreement with the experimental data.国家自然科学基金项目,批准号为 :20003008,2983306