Design and Implementation of Dynamic High-Speed Switches in Super Base Station Architectures

Novel centralized base station architectures integrating computation and communication functionalities have become important for the development of future mobile communication networks.Therefore,the development of dynamic high-speed interconnections between baseband units(BBUs)and remote radio heads(RRHs)is vital in centralized base station design.Herein,dynamic high-speed switches(HSSs)connecting BBUs and RRHs were designed for a centralized base station architecture.We analyzed the characteristics of actual traffic and introduced a switch traffic model suitable for the super base station architecture.Then,we proposed a data-priority-aware(DPA)scheduling algorithm based on the traffic model.Lastly,we developed the dynamic HSS model based on the OPNET platform and the prototype based on FPGA.Our results show that the DPA achieves close to 100%throughput with lower latency and provides better run-time complexity than iOCF and HE-iSLIP,thereby demonstrating that the proposed switch system can be adopted in centralized base station architectures.

Super-Shuffle Product and Cut-Box Coproduct on (0,1)-Matrices

In 2014, Vargas first defined a super-shuffle product and a cut-box coproduct on permutations. In 2020, Aval, Bergeron and Machacek introduced the super-shuffle product and the cut-box coproduct on labeled simple graphs. In this paper, we generalize the super-shuffle product and the cut-box coproduct from labeled simple graphs to (0,1)-matrices. Then we prove that the vector space spanned by (0,1)-matrices with the super-shuffle product is a graded algebra and with the cut-box coproduct is a graded coalgebra.

基于高斯超像素的快速Graph Cuts图像分割方法

提出了一种交互式的快速图像分割方法.该方法通过使用高斯超像素来构建Graph cuts模型以实现加速.首先,利用融合了边缘置信度的快速均值漂移算法,将原始图像高效地预分割为多个具有准确边界的同质区域,并将这些区域描述为超像素,用于构建精简的加权图.然后,使用区域的彩色高斯统计对超像素进行特征描述,并在信息论空间中对高斯距离度量进行设计.另外,为了准确而精炼地对先验知识进行参数化学习,本文还使用了分量形式的期望最大化混合高斯(Component-wise expectation-maximization for Gaussian mixtures,CEMGM)算法对用户交互进行聚类.最后,在改进的加权图模型中应用Graph cuts方法,获得最终的分割结果.通过使用不同的彩色图像进行分割实验比较,仿真结果表明本文的方法在准确性和高效性方面都具有很好的性能.

基于改进Graph Cut算法的生猪图像分割方法

生猪图像分割为生猪行为特征提取、参数测量、图像分析、模式识别等提供易于理解和分析的图像表示,准确有效的生猪图像分割是生猪行为理解和分析的基础。针对传统Graph Cut算法分割精度差、分割效率低及不能准确分割特定目标的问题,该文结合交互分水岭算法,提出基于改进Graph Cut算法的生猪图像分割方法。采用交互分水岭算法对图像进行区域划分,划分的各个区域块看作超像素,用超像素替代传统加权图中的像素点,构造新的网络图替代传统加权图,重新构造能量函数以完成前景背景的有效分割。试验结果表明:该方法峰值信噪比平均范围为[30,40],结构相似度平均范围为[0.9,1],两种评价准则的结果与主观评价一致,图像分割质量、精度得到明显提升;平均耗时缩短到传统Graph Cut算法的33.7%,提高了分割效率;在复杂背景、噪声干扰、光照强度弱等条件下可以快速分割出特定目标生猪,具有较高鲁棒性。

一种古建墙壁受污文字图像的多特征引导Grab Cut分割方法

古建墙壁题记毛笔文字受霉变污染影响,字迹不清,不利于辨识,而传统算法对文字图像进行分割时未充分考虑污染和文字的特征信息,结果中往往存在误分割或缺损现象。本研究提出一种结合图像偏振信息的多特征引导Grab Cut分割算法,该方法首先对采集的0°、45°、90°、135°四个角度偏振图像进行斯托克斯解算,得到偏振度特征图;然后利用SLIC对可见光相机采集的题记图像进行超像素分割,并提取超像素的颜色特征距和纹理特征距;最后,用偏振度约束区域项,特征距引导边界项,进行Grab Cut分割,得到毛笔文字分割结果。实验结果表明,本算法与未考虑偏振和特征距信息的图割算法相比,分割效果得到较大改善。研究结果可为书法研究和文字拓本的数字化存储提供有力的科学支持,也为题记的实体去污修复过程提供充足的科学指引和实验环境。

超大断面扁平结构隧道施工参数优化研究

基于某超大断面扁平结构隧道的上下台阶法施工段,采用数值模拟方法研究在该工程地质条件下台阶长度和锚杆纵距2种施工参数改变带来的影响。利用数值模型对不同台阶长度(分别为30,40,50,60 m)和不同锚杆纵距(分别为1.0,1.5,2.0 m)情况进行研究,对隧洞周边岩体中塑性区、围岩应力和围岩变形情况的分布规律进行分析,结合数值结果和现场监测数据验证了施工现场采用台阶长度为50 m和锚杆纵距为1 m的施工参数较合理。该研究成果可为超大断面扁平结构隧道的开挖和支护施工参数的合理选取提供参考。

巷旁充填留巷顶板结构分析与围岩控制技术

为研究沿空留巷顶板结构特征及其支护技术,基于弹性力学薄板理论,建立了沿空留巷顶板悬板结构模型,推演了两种边界条件下悬板主应力表达式,构建了应力比例系数作为薄板破坏判据,研发了沿空留巷巷内顶板斜拉锚索加强支护、巷旁超高水材料复合支护技术。研究结果表明:锚网索支护沿空留巷过程中实施超前预裂切顶,顶板可形成悬板结构,该结构随上覆顶板运动可形成一对边简支一对边自由和一对边固支简支一对边自由两种悬板形式;在矿山压力作用下两种悬板破坏部位不同,可以此作为布置顶板斜拉锚索的依据;顶板斜拉锚索对悬板起悬吊和水平挤压作用。现场试验结果证明了理论分析的可靠性。

山岭隧道超大断面盾构组装洞室关键施工技术

以渝湘高铁重庆到黔江段重庆长江隧道为例,针对该隧道洞室施工工艺复杂、施工难度大、危险性高、施工周期长的特点,提出了盾构组装洞室总体施工方案,即盾构组装洞室采用分部分层台阶法施工,对其施工工艺及施工方法进行详细论述,结果表明,该施工技术科学合理、安全可行。

基于Graph Cut和超像素的自然场景显著对象分割方法

针对自然场景图像,提出了一种快速的显著对象自动分割方法.首先,将图像从RGB颜色空间变换至HSV颜色空间,利用色调和亮度等特征获得显著度图,得到待分割对象所在的区域;然后利用改进的分水岭算法将原始图像预分割为若干子区域,将这些区域描述为超像素,使用混合高斯分布描述其特征,用于构建图切分方法的网络图,经过迭代分割之后,获得最终的显著对象.实验结果表明,该算法与人工交互的图切分算法相比,能自动获得前景和背景的先验知识,在不影响分割精度的情况下,加快了分割速度.

基于超像素与特征改进的Grab cut前景分割

Grab cut算法在分割图像时需要的交互量少且分割精度高,但效率偏低。使用SLIC超像素算法作为预处理可以明显提高Grab cut算法的效率,但是,在前景与背景颜色特征相差不大的情况下分割精度较低。针对这个问题,提出一种基于超像素与特征改进的Grab cut算法。利用SLIC算法预处理图像,计算超像素的颜色特征和纹理特征,最后将这两种特征乘以权重得到新的边界项,代入能量函数计算最小割。实验表明,改进的算法在时间和精度上都有很好的性能。

Chatter stability and precision during high-speed ultrasonic vibration cutting of a thin-walled titanium cylinder

Titanium alloys are widely used in the aviation and aerospace industries due to their unique mechanical and physical properties.Specifically,thin-walled titanium(Ti)cylinders have received increasing attention for their applications as rocket engine casings,aircraft landing gear,and aero-engine hollow shaft due to their observed improvement in the thrust-to-weight ratio.However,the conventional cutting(CC)process is not appropriate for thin-walled Ti cylinders due to its low thermal conductivity,high strength,and low stiffness.Instead,high-speed ultrasonic vibration cutting(HUVC)assisted processing has recently proved highly effective for Ti-alloy machining.In this study,HUVC technology is employed to perform external turning of a thinwalled Ti cylinder,which represents a new application of HUVC.First,the kinematics,tool path,and dynamic cutting thickness of HUVC are evaluated.Second,the phenomenon of mode-coupling chatter is analyzed to determine the effects and mechanism of HUVC by establishing a critical cutting thickness model.HUVC can increase the critical cutting thickness and effectively reduce the average cutting force,thus reducing the energy intake of the system.Finally,comparison experiments are conducted between HUVC and CC processes.The results indicate that the diameter error rate is 10%or less for HUVC and 51%for the CC method due to a 40%reduction in the cutting force.In addition,higher machining precision and better surface roughness are achieved during thin-walled Ti cylinder manufacturing using HUVC.

Modeling high-speed cutting of SiC_(p)/Al composites using a semi-phenomenologically based damage model

In this paper,we attempts to investigate cutting mechanisms in high-speed cutting of Al6061/Si C_(p)/15p composites using a semi-phenomenologically based damage model in the equivalent homogeneous material(EHM)framework.By combining macroscale EHM modeling and underlying microscale physical mechanisms,a feasible semi-phenomenological plastic model is proposed for prediction of cutting forces and chip morphology during high-speed turning Al6061/Si C_(p)/15p composites.This model incorporates the modified Weibull weakest-link effect to represent the strain-based damage evolution in large deformations.This proposed semi-phenomenological constitutive model is implemented by compiling material subroutines into cutting finite element(FE)codes.The effects of the critical shear stresses on chip formation that depend on the toolchip frictional coefficient are accounted for in the cutting FE model.The chip formation mechanism affecting material removal behaviors during high-speed turning is further investigated.The capabilities of the proposed constitutive model are evaluated by comparing cutting forces and chip morphologies between experiments and simulations at different cutting speeds associated with strain rates.The EHM-based and microstructure-based models are further compared in both computational efficiency and accuracy.The simulation results show that the developed semiphenomenological constitutive formalism and cutting model are promising and efficient tools for further investigation of dynamic mechanical and cutting behaviors of particle-reinforced composites with different volume fraction and particle size.

Chip morphology and cutting temperature of ADC12 aluminum alloy during high-speed milling

The ADC12 aluminum alloy is prone to severe tool wear and high cutting heat during high-speed milling because of its high hardness.This study analyzes the highspeed milling process from the perspective of different chip morphologies.The influence of cutting temperature on chip morphology was expounded.A two-dimensional orthogonal cutting model was established for finite element analysis(FEA)of high-speed milling of ADC12 aluminum alloy.A theoretical analysis model of cutting force and cutting temperature was proposed based on metal cutting theory.The variations in chip shape,cutting force,and cutting temperature with cutting speed increasing were analyzed via FEA.The results show that,with the increase in cutting speed,the chip morphology changes from continuous to serrated,and then back to continuous.The serrated chip is weakened and the cutting temperature is lowered when the speed is lower than 600 m·min^(-1)or higher than 1800 m·min^(-1).This study provides a reference for reducing cutting temperature,controlling chip morphology and improving cutting tool life.

Research on cutting characteristics of fiber bundle with high-speed photography

Cutting is an essential and complicated process in many fields.Efficient and low-consumption cutting operations are of great significance for environmental protection and energy conservation.The development of high performance cutting parts relies on a deep understanding of the cutting process and cutting mechanism.In this research,a new type of cutting test bench with high-speed photography was developed,and the cutting tests were conducted on the jute fiber bundle from quasi-static cutting at 10 mm/s to dynamic cutting in the speed range of 0.6-2.4 m/s.The cutting process was captured by a high-speed camera.Analysis shows that compression exists before quasi-static cutting,and the compression force curve with respect to the compression ratio follows an exponential function.The cutting speed has a significant effect on cutting energy.The cutting energy consumption is not a monotonous function of cutting speed owing to the combined effect of elastic deformation and friction of fibers.The cutting energy increases with increasing cutting speed in the range of 0.6-1.2 m/s due to the increase of the friction within fibers and the friction between the blade and fibers.The cutting energy decreases with increasing cutting speed in the range of 1.2-1.8 m/s,and tends to be a fixed value when the cutting speed exceeds 1.8 m/s due to the stabilized elastic deformation and friction coefficient.From the perspective of energy saving,it is meaningless to increase the blade speed excessively when cutting fiber bundles.

温度对汽车零部件切削加工用PCBN复合材料结构与性能的影响研究

以TiN作为主要结合剂,加入一定量的Al粉和Ti粉,研究了烧结温度(1300~1600℃)对TiN⁃Al⁃Ti结合立方氮化硼(CBN)烧结合成聚晶立方氮化硼(PCBN)复合材料的组成、显微结构以及力学性能的影响。结果表明,PCBN试样的物相主要为BN、TiB_(2)、TiN、AlN,烧结过程中Ti与CBN反应生成TiN和TiB_(2)相;PCBN的相对密度、抗弯强度以及硬度随着烧结温度升高总体上呈上升趋势。1500℃烧结时,可以得到综合性能好的复合材料,其相对密度、抗弯强度、断裂韧性和显微硬度分别为99.1%、807.8 MPa、6.2 MPa·m^(1/2)和3233HV。

“三超”气井永久式封隔器完井管柱处理工艺技术研究及实践

克深气田埋藏超深(≥6000 m)、地层压力超高(≥120 MPa)、地层温度超高(≥165℃),气井采用井下安全阀+THT永久式封隔器完井管柱投产。针对“三超”气井生产管柱断落、变形、腐蚀泄漏,严重影响气井正常生产问题,开展了井下管柱处理工艺技术研究,形成了包括压井、径向切割炬RCT(Radial Cutting Torch,RCT)切割、永久式封隔器处理、落鱼打捞及相应工具选择在内的配套工艺技术。2015年至今己成功地对20余口事故井进行了修复,取得了良好效果,研究为“三超”气井大修复杂处理提供了可借鉴的经验。

PCBN刀具以车代磨加工20CrMnTi合金钢试验研究

采用聚晶立方氮化硼(PCBN)刀具,以车代磨对20CrMnTi合金钢进行精密切削加工。分析了切削过程中PCBN刀具的磨损形式和磨损机理,研究了不同切削参数对刀具寿命与工件表面粗糙度的影响。结果表明,切削过程中刀具发生了扩散、崩刃以及氧化磨损;在硬态切削三要素中,切削进给量和切削速度对刀具磨损量影响较大,切削进给量对工件表面粗糙度影响较大。

保水剂和水泥含量对切挖边坡人工土壤钾素的影响

了解保水剂和水泥对人工土壤钾素的影响有助于提高土壤钾素有效性,有利于边坡的植被恢复.本文以保水剂和水泥为基质原材料,选用L_(9)(3^(2))正交表进行试验,研究不同保水剂和水泥含量对土壤钾素形态的影响以及作用机制.结果表明,保水剂和水泥显著增加土壤速效钾、非交换性钾、水溶性钾、特殊吸附钾和非特殊吸附钾含量,而土壤全钾和矿物钾含量均有不同程度地减少.同时,0.30%保水剂和4%水泥能显著提高黑麦草的发芽率,但是过量的保水剂和水泥则明显降低了种子的发芽率.相关性分析表明,土壤pH与土壤有机质是影响土壤钾素有效性的重要因子.保水剂和水泥的施用可提高土壤中速效钾和非交换性钾的含量,促进土壤钾素组分之间的转化,提升土壤钾素有效性.

单管集油工艺在超稠油区块高含水期的应用研究

超稠油随着蒸汽吞吐、蒸汽驱、SAGD开发,地下温场逐步形成,出井温度、综合含水率升高。传统的三管伴热工艺不仅能耗高,设施老化问题突出,并且已建的伴热规模无法满足新增生产井产出液的集输需求。为了降低地面系统整体能耗,优简站场布局,开展了高含水期超稠油单管集输技术研究,取消三管伴热高能耗流程,根据区块生产特点及已建地面工艺系统情况,结合含水油流变特性,进行温度、含水率、流量及集输半径4方面因素对单管集油工艺影响的边界条件分析,得出不同工况下的界限曲线,提出解决单井停产时原油粘壁难题的可实施方案。将理论应用于现场试验,形成井场内环状串接集油+井场间合并集输工艺模式,偏远低产井通过电加热方式改善集输条件,实现高含水期超稠油单管集油,经济效益显著,为全区块优化工艺提供可靠依据。

8.8 m超大采高工作面提高开机率方案探索与应用

以上湾煤矿12402超大采高综采工作面为背景,针对工作面投产后出现的开机率较低严重制约工作面高产高效的难题,经过关联图分析得出检修不到位、工程质量管控不到位、组织协调不到位是制约工作面开机率的三大因素。进一步确认得出检修不到位、工程质量管控不到位是重要因素,并应对这两大重要因素提出做好矿压预测、预煤层走势、完善设备检修标准、制定重点检修项目等解决方案。方案实施后,开机率显著提升,为企业带来巨大经济效益。