Round-Robin协议下非线性时变系统的保概率H_(∞)滤波

针对实际系统存在各种不可预知的扰动,造成系统很难精确地达到期望的各项性能指标,研究了基于Round-Robin协议的一类非线性时变系统的保概率H_(∞)滤波问题。利用概率约束H_(∞)性能指标,使该系统更贴近实际工程应用。同时,考虑在数据传输过程中产生的网络拥塞和资源占用现象,采用Round-Robin协议对网络节点间的数据传输进行调度。考虑信号从传感器至待设计滤波器传输过程中具有非线性扰动,构造保概率非脆弱H_(∞)滤波器。其不确定参数由服从均匀分布且相互独立的随机变量控制,同时通过寻求线性矩阵不等式工箱设计能在概率约束下保证性能要求的滤波器。利用递推线性矩阵不等式方法求解保概率H_(∞)滤波问题。最后,通过仿真示例,证明所提出的滤波方案的有效性。

时隙间迭代的输入队列交换机Round-Robin调度算法

输入队列因具有良好的可扩展性而广泛应用于高速交换机和路由器中,但输入队列需要精心设计调度算法以获取较好的性能.Round-Robin 算法因其简单性和并行性而得到广泛的研究,但现有的 Round-Robin 算法在突发流量和非均匀流量下的负荷-延迟性能较差.提出了调度决策在时隙间进行迭代的思想,并利用队列长度具有随机性的特点设计了能近似最大匹配的 Round-Robin 算法——iSLOT.仿真结果表明,iSLOT 不仅在均匀流量下是稳定的,在非均匀流量和突发流量下的吞吐率及延迟性能均远好于现有的 Round-Robin 算法.

Round robin调度算法在FPGA中的实现

Round robin调度算法是一个在许多方面有着广泛应用的经典调度算法。该文在考虑了FPGA的结构特点和实际系统需求后,利用桶式移位器和分段式优先级编码器,在FPGA中实现了Round robin调度算法,并对实现方法的面积和性能进行了讨论。系统测试结果表明该算法实现是高效的,满足了系统的需求,在实际系统中运行状况良好。

基于螺旋线的Round-Robin Crossbar调度算法

该文提出了一种基于螺旋线的 Round-Robin(R-R)crossbar调度算法,在调度级和迭代级分别轮询R-R指针,避免了指针同步;在输入端口轮询和迭代匹配的二维过程,执行流水线操作。当端口数<32时,执行效率高,带宽利用率高,逻辑简单,容易实现。通过对R-R加权,可以保证Non-uniformtraffic高吞吐量。

一种可配优先级Round-Robin仲裁器实现

本文介绍了一种结合Round-Robin,优先级可配置的多端口仲裁器设计及实现。该设计可以实现高优先级请求优先服务,相同优先级请求之间进行轮循的调度策略,同时将原子指令仲裁保护逻辑加入到设计当中,实现了合理的时序逻辑优化,可以很好地应用于多通道访存控制器的设计当中。

基于语料库的“V(a)round”构式搭配关联强度及动词“V”语义聚类研究

基于COCA语料库,对出现于"V(a)round"构式的动词进行检索,并使用Fisher精确检验计算搭配强度。研究发现:进入构式V槽的动词主要有两大类,相对静止动词和位置发生变换的动词;根据动词的不同,构式的凸显有所不同,主要有:对动作结果的突出,对方式、路线和范围的突出,对相邻、相关内容的突出,对动作持续性和连续性的突出;根据构式凸显的不同,构式义相应地可以有:表示动作的结果,表示动作的方式、路线和范围,表示动作相邻、相关内容,表示动作发生时伴随的状态。基于语料库的"V(a)round"构式搭配强度及其语义的分析,不仅有助于进一步了解该构式,也是对构式搭配分析法的进一步应用,对我国外语教学也有一定的启示。

ROUNDED FLOWING STATES OF OBSTRUCTED BUOYANT JET

The mutual relationships of three effective factors, the diameter D/d （d is the diameter of exit） of obstructed plate, exit densimetric Froude number and the distance Hid of the plate from jet orifice for obstructed buoyant jet in static ambient, are analyzed to explain normal and abnormal rounded flowing （reverberated and bifurcated flowing）. The critical Froude numbers for obstructed buoyant jets with H/d=2, 4, 6, 8 which distinguished normal and abnormal flowing pattern are obtained. Normal rounded flowing is found only for a plate under a special value of H/d. A fitted formula of critical Froude numbers with H/d and D/d is presented to distinguish rounded flowing types. The occurring of reverberated or bifurcated flowing in abnormal rounded flow is analyzed. Based on the results of obstructed buoyant jets with D/d=1, normal rounded flowing occurred only for all conditions and axial dilution behind the plate under different H/D is obtained.

适用于虚通道路由器的高性能round-robin仲裁器

分析了交换结构规模不同的2类典型的虚通道路由器体系结构,指出了交换结构规模对调度机制和仲裁器体系结构的显著影响.在轮转(round-robin)仲裁器PPE的基础上,提出了分别适用于上述2类路由器的改进型PPE仲裁器体系结构.改进型仲裁器将原有关键路径中的处理步骤转移到非关键路径中,并行实现了关键路径中的重要处理步骤,通过缩短关键路径改善了仲裁器的性能;同时通过调整仲裁流程消除了上述改进对资源成本的负面影响.基于TSMC 0.35μm CMOS工艺实现了不同规模的PPE和2种改进型仲裁器体系结构.实验结果表明上述2种改进型仲裁器比PPE仲裁器的性能分别提高12%和17%以上,并且在多数情况下同时减少了实现面积.

网络攻击下基于Round-Robin协议的数字化电力网络的递推状态估计

研究了一类在Round-Robin(RR)协议下遭受网络攻击的数字化电力网络的递推状态估计问题。数字化电力网络中状态估计器和传感器之间的数据传输过程存在被攻击者监听的风险。设计了一种可应用于数字化电力网络的递推状态估计器,能够在保证误差协方差上界的同时,减少网络攻击对状态估计精度的影响;构建了一个含有拒绝服务(DoS)攻击和欺骗攻击的网络攻击模型,并采用RR协议来处理网络堵塞问题;利用代数黎卡提方程方法和随机分析方法,推导误差协方差的上界;最后,通过数值仿真验证了所提出的递推状态估计器设计方案的有效性。

Clinical and computed tomography features of adult abdominopelvic desmoplastic small round cell tumor

To investigate the clinical and computed tomography(CT)features of desmoplastic small round cell tumor(DSRCT),we retrospectively analyzed the clinical presentations,treatment and outcome,as well as CT manifestations of four cases of DSRCT confirmed by surgery and pathology.The CT manifestations of DSRCT were as follows:(1)multiple soft-tissue masses or diffuse peritoneal thickening in the abdomen and pelvis,with the dominant mass usually located in the pelvic cavity;(2)masses without an apparent organbased primary site;(3)mild to moderate homogeneous or heterogeneous enhancement in solid area on enhanced CT;and(4)secondary manifestations,such as ascites,hepatic metastases,lymphadenopathy,hydronephrosis and hydroureter.The prognosis and overall survival rates were generally poor.Commonly used treatment strategies including aggressive tumor resection,polychemotherapy,and radiotherapy,showed various therapeutic effects.CT of DSRCT shows characteristic features that are helpful in diagnosis.Early discovery and complete resection,coupled with postoperative adjuvant chemotherapy,are important for prognosis of DSRCT.Whole abdominopelvic rather than locoregional radiotherapy is more effective for unresectable DSRCT.

Adenoviral-mediated Hath1-EGFP gene transfer into guinea pig cochlea through intact round window membrane

Objective To study expression of adenoviral-mediated Hath1-EGFP gene in the guinea pig cochlea after transfer through intact round window membrane(RWM), and to assess its effects on hearing. Methods Twenty adult guinea pigs were used, of which: 12 were surgically inoculated with Ad-Hath1-EGFP in the bony groove of round window niche, and 8 with artificial perilymph. Auditory brainstem response(ABR) thresholds were determined in all animals before and 5 days after surgery. On post-surgery day 5 and day 14, animals were sacrificed and whole mounts of cochlea and frozen sections were examined. Results ABR tests showed no significant change of hearing after the surgery. Strong fluorescence staining in the cochleae was seen in Ad-Hath1-EGFP groups. The highest levels of gene expression were seen in the post-surgery day 5 group with little decrease on post-surgery day 14.The contralateral cochlea and those in the control groups were free of fluorescence staining. Conclusion The transgenic Hath1-EGFP can be effectively delivered into the inner ear through intact RWM, in an atraumatic manner.

基于Round Robin无线调度策略的公平性分析

在无线调度策略中,保证公平性和提高系统吞吐量是矛盾的,因为保证公平性是以牺牲系统吞吐量为代价的。本文首先给出基于Round Robin无线调度策略的时间公平性和容量公平性定义,然后研究在一定系统吞吐量下调度策略可以保证的最大时间公平性和容量公平性,并在理论上证明在相同吞吐量下时间公平性不小于容量公平性,仿真结果表明了理论分析的正确性。

Quantitative Prediction of Reduction in Large Pipe Setting Round Process

The control manner during the process to ensure the quality of pipe products mainly relies on the operator’s experience, so it is very necessary to study the setting round process and obtain its spring-back law. The setting round process is shaping an oval section pipe into circular section, so it is difficult to provide a quantificational analysis for its spring-back process because of the curvature inequality of pipe section neutral layer. However, the spring-back law of the circle-oval process can be easily predicted. The experimental method is firstly used to establish the equivalent effect between the setting round process and the circle-oval process. The setting round process can be converted into the circle-oval process. There are two difficulties in the theoretical analysis for the circle-oval process: elastic-plastic bending problem of curved beam; statically indeterminate problem. A quantitative analytic method for the circle-oval process is presented on the basis of combination of the spring-back law of plane curved beam with the element dividing idea in finite element method. The ovality after unloading versus the relative reduction is plotted with analytical and experimental results respectively, which shows a fair agreement. Finally, the method of quantitative prediction of reduction for large pipe setting round is given based on the equivalent effect and the analytical results. Five pipes, which are needed to be set round, are used to carry out experiment so as to verify this method. The results of verification experiment indicates that, in the experimental range, the residual ovality are all under 0.35% after the once only setting round with the theoretical prediction reductions. It is much less than the 1% requirement of pipe standard. Applying the established theoretical analysis is able to correct the pipe ovality with sufficient accuracy, which provides theoretical direction to plant use.

Frost heave control of fine round gravel fillings in deep seasonal frozen regions

Fine round gravel soil is widely employed in the subgrade of high and thawing. The lower the fines content in fine round gravel soil, but compaction difficulty increases. This study is to obtain the speed railways in cold regions to prevent frost heaving the smaller the quantities of frost heaving and thawing, optimum fines content and limited frost heaving and thawing. The fine round gravel soil filling （FRGSF） used in the Harbin-Qiqihaer Passenger Dedicated Line is taken as the study object. Influence of fines content on optimum water content, maximum dry density and frost heaving properties of FRGSF were studied by means of compaction and frost heaving tests. Results show that the maximum dry density of the FRGSF increases first and then decreases with an increase of fines content, namely there is an optimum fines content for easy compaction. The method of surface-vibratory instrument is fit for coarse-grained soils, and wet state of coarse-grained soil is in favor of compaction. Considering the relationship of fines content with maximum dry density and the frost heaving ratio of FRGSF, the fines content should be limited to within the range of 9%-10%, so that the frost heaving ratio is less than 1%, and the FRGSF is easily compacted. Water supply is proved to be an important factor influencing the amount of frost heaving of FRGSF. We also conclude that in the field, it is imperative to control waterproofing and drainage measures.

Improving precision in the assessment of round cell numbers in human semen

The aim of this study was to increase the precision of assessment of the number of round cells observed in the per- oxidase test for detection of seminal leukocytes （granulocytes）. The dilution of semen was reduced and the volume of suspension examined was increased for semen samples containing between 0.6 and 6 million round cells per mL. A 1 ＋ 5 （1：6） dilution was compatible with measurable peroxidase activity and a sufficiently clear background for cell assessment. At this dilution, and with assessment of all 18 grids on both sides of the Neubauer-improved counting chamber, only three of the 10 samples （nominal cell concentrations of 1.9 ×10^-6-3.3×10^-6 mL-1） presented 400 round cells or more. As lower seminal dilutions were incompatible with easy detection of round cells or their peroxidase reaction product, it was not pos- sible to provide precise measurements （sampling error 5%） of the suggested lower reference limit of 1 ×10^-6 cells per mL. The results indicate that this poor precision of measuring 1×10^-6 round cells per mL could explain the discrepant reports on the acceptability of the cut-off values for leukocytospermia. Such reference limits need to be established with statistically sound methods.

Surface Roughness and Roundness of Bearing Raceway Machined by Floating Abrasive Polishing and Their Effects on Bearing's Running Noise

As the two most important indexes of bearing raceway, surface roughness and roundness have significant influence on bearing noise. Some researchers have carried out studies in this field, however, reason and extent of the influence of raceway surface geometric characteristics on bearing running noise are not perfectly clear up to now. In this paper, the raceway of 6309 type bearing＇s inner and outer ring is machined by floating abrasive polishing adopting soft abrasive pad. Surface roughness parameters, arithmetical mean deviation of the profile Ra, the point height of irregularities Rz, maximum height of the profile Rmax and roundness fof raceways, are measured before and after machining, and the change rules of the measured results are studied. The study results show that the floating abrasive polishing can reduce the surface geometric errors of bearing raceway evidently. The roundness error is reduced by 25%, Rm^x value is reduced by 35.5%, Rz value is reduced by 22% and Ra value is reduced by 5%. By analyzing the change of the geometrical parameters and the shape difference of the raceway before and after machining, it is found that the floating abrasive polishing method can affect the roundness error mainly by modifying the local deviation of the raceway＇s surface profile. Bearings with different raceway surface geometrical parameter value are assembled and the running noise is tested. The test results show that Ra has a little, Rmax and Rz have a measurable, and the roundness error has a significant influence on the running noise. From the viewpoint of controlling bearings＇ running noise, raceway roundness error should be strictly controlled, and for the surface roughness parameters, R,n^x and Rz should be mainly controlled. This paper proposes an effective method to obtain the low noise bearing by machining the raceway with floating abrasive polishing after super finishing.

Passive VIV Reduction of An Inclined Flexible Cylinder by Means of Helical Strakes with Round-Section

A series of experimental tests of passive VIV suppression of an inclined flexible cylinder with round-sectioned helical strakes were carried out in a towing tank. During the tests, the cylinder models fitted with and without helical strakes were towed along the tank. The towing velocity ranged from 0.05 to 1.0 m/s with an interval of 0.05 m/s.Four different yaw angles(a=0°, 15°, 30° and 45°), defined as the angle between the axis of the cylinder and the plane orthogonal of the oncoming flow, were selected in the experiment. The main purpose of present experimental work is to further investigate the VIV suppression effectiveness of round-sectioned helical strakes on the inclined flexible cylinder. The VIV responses of the smooth cylinder and the cylinder with square-sectioned strakes under the same experimental condition were also presented for comparison. The experimental results indicated that the roundsectioned strake basically had a similar effect on VIV suppression compared with the square-sectioned one, and both can significantly reduce the VIV of the vertical cylinder which corresponded to the case of a=0°. But with the increase of yaw angle, the VIV suppression effectiveness of both round-and square-section strakes deteriorated dramatically, the staked cylinder even had a much stronger vibration than the smooth one did in the in-line(IL)direction.

Analysis and Application of Multiple-Precision Computation and Round-off Error for Nonlinear Dynamical Systems

This research reveals the dependency of floating point computation in nonlinear dynamical systems on machine precision and step-size by applying a multiple-precision approach in the Lorenz nonlinear equations. The paper also demoastrates the procedures for obtaining a real numerical solution in the Lorenz system with long-time integration and a new multiple-precision-based approach used to identify the maximum effective computation time （MECT） and optimal step-size （OS）. In addition, the authors introduce how to analyze round-off error in a long-time integration in some typical cases of nonlinear systems and present its approximate estimate expression.

NUMERICAL STUDY ON THE STABILITY AND MIXING OFVERTICAL ROUND BUOYANT JET IN SHALLOW WATER

The k-epsilon model was applied to establish the mathematical model of vertical round buoyant jet discharging into confined depth, and it was solved using the Hybrid Finite Analytic Method (HFAM). The numerical predictions demonstrate two generic flow patterns for different jet discharge and environmental parameters: (ⅰ)a stable buoyant flow discharge with the mixed fluid leaving the near-field warm in a surface warm water layer; (ⅱ)an unstable buoyant flow discharge with recirculation and re-entrainment of warm water in the near field. Furthermore, the mixing characters of vertical round buoyant jet were numerically predicted. Both the stability criterion and numerical predictions of bulk dilutions are in excellent agreement with Lee and Jirka's experiments and theory.

Mechanical model of round window membrane under reverse excitation

According to the vibration characteristics of the round window, a mechani- cal model of a round window membrane is established. The Euler equation of the round window and the complementary boundary conditions are derived by the variational prin- ciple. Combined with the Bessel function, an analytical solution of the round window displacement is obtained by MATHEMATICA. Combined with clinical characteristics of round window membrane lesion, the effect of sound transmission due to thickening of the round window membrane caused by the otitis media, shrinkage of the round window membrane area caused by otosclerosis, and hardening of the round window membrane itself is analyzed. The results show that with thickening of the round window membrane, the displacement of the round window membrane is decreased. In the meantime, with hardening of the round window membrane and shrinkage of the membrane area, the max- imum displacement Of the round window membrane is gradually reduced, leading to a decrease in sound transmission. Thus, the analyticM analysis can avoid interference of environment and the technical level of personnel, and it can evaluate transmission per- formance of the round window membrane efficiently, providing a theoretical basis for the reverse excitation of artificial prosthesis.