Fibre backbone for cable TV using multi-channel am video trunking

This paper updates a scenario for the evolutionary integration of optical fibre transmission technology into existing cable television networks first presented in 1988. The resulting ‘fibre backbone’ yields a hybrid fibre/coaxial network with significantly better reliability and transmission quality than present systems. System and electro-optical component advances in the last year are reviewed, and the merits of various modulation techniques are examined. The fibre backbone approach emphasizes continuing the broadband delivery of a large number of video signals to the consumer.     

无线传感器网络中d-Hop 2-连通容错支配集的分布式构造算法

无线传感器网络随节点移动组成自我维持的自组织系统,采用连通支配集的虚拟骨干技术可使平面网络系统层次化而简化节点路由、管理和维护。但大规模无线传感器网络的连通支配集节点数目依然庞大,d-hop连通支配集可以大大减小支配集节点数目。另外,由于存在节点失效、链路断裂等无线特性,虚拟骨干网需要具备一定的容错性。在单位圆盘图网络模型中为构建精简且具有容错能力的虚拟骨干网,提出d-hop 2-连通支配集的分布式构造算法,先构造d-hop独立支配集后再连通形成d-hop 2-连通支配集。并从理论和仿真上对算法的复杂度、近似比和算法性能作了进一步探讨和验证。     

骨料颗粒与多孔材料显微结构关系的研究

本文阐述了多孔材料的孔隙率与生产工艺的关系 ,结合显微结构分析了骨料粒径及其分布对多孔材料的孔隙率、抗折强度的影响。     

软件多分支开发代码漏合问题及解决途径

代码管理是软件开发过程的一个重要的环节,随着软件需求和功能的日益复杂,多分支开发场景越来越普遍,使得代码管理的难度直线上升,分支间代码漏合问题也应运而生,严重影响了开发的效率和版本的交付质量,本文根据个人的代码管理经验,对常用的分支管理模式进行了研究与分析,并主要基于分支开发、分支发布模式对多分支代码漏合问题进行了解决途径的研究.实践应用结果表明可以有效避免分支代码漏合问题,优化代码管理过程,提高整体代码管理的效率.     

一种高效的车体表面损伤检测分割算法

车体表面损伤检测是计算机视觉中的经典问题。车体表面损伤检测的主要瓶颈在于图像中损伤实例的不同尺度影响了分割的精度与效率。本文采用单阶段语义分割网络（YOLACT⁺⁺）进行车体表面的损伤检测,通过结合EfficientNet设计主干网络提高分割效率,并通过改进损失函数优化YOLACT⁺⁺中目标实例Mask的生成,实验中用深度学习标注实验数据集进行训练测试。实验表明,改进后的YOLACT⁺⁺降低了Mask生成误差,检测的实时帧率提高到35帧/s,同时也提高了YOLACT⁺⁺进行实例分割的精度。     

战场宽带数据链分布式虚拟骨干网的构建

宽带数据链作为现代战场的神经网络和信息传输通道,必须采用分布式虚拟骨干网构建算法才能适应战场环境的大容量、多样性数据传输和时变性网络结构。针对这一问题,提出了一种分布式虚拟骨干网构建算法-DCDS算法。该算法中,每个节点只需获取其两跳范围内的邻居节点信息,无需获知全网拓扑信息。理论分析和仿真表明,相比Wu等2种经典算法,DCDS算法具有更小的消息开销和虚拟骨干网构建规模,更适合于大数据量、高动态的战场宽带数据链网络。     

A parallel ant colonies approach to de novo prediction of protein backbone in CASP8/9

Predicting the three-dimensional structure of proteins from amino acid sequences with only a few remote homologs,or de novo prediction,remains a major challenge in computational biology.The modeling of the protein backbone represents the initial phase of a protein structure prediction process.Using a parallel ant colony optimization based on sharing one pheromone matrix,this report proposes a parallel approach to predict the structure of a protein backbone.The parallel approach combines various sources of energy functions and generates protein backbones with the lowest energies jointly determined by the various energy functions.All free modeling targets in CASP8/9 are used to evaluate the performance of the method.For 13 targets in CASP8,two out of the predicted model1s selected by our approach are the best of the published CASP8 results,and seven out of the model1s are ranked in the top 10.For 29 targets in CASP9,20 out of the best models from our predictions are ranked in the top 10,and 11 out of the model1s are ranked in the top 10.     

BK-means:骨架初始解K-means

K-means是典型的启发式聚类算法,容易受到初始解的影响而无法获得高质量的聚类结果。骨架是近年来启发式算法设计的研究热点,它是指所有全局最优解中相同的部分,对于提高启发式算法性能具有重要意义。给出的骨架初始解K-means算法(BK-means)的基本思想是:首先利用K-means算法得到一组局部最优解(聚类结果),通过对局部最优解求交得到骨架簇。利用骨架簇构造骨架初始解及新的搜索空间。最后以骨架初始解引导K-means算法在新的搜索空间中搜索聚类结果。在15组仿真数据集和4组实际数据集上的实验结果表明,BK-means算法具有获得高内聚、高分离的聚类结果能力。     

Backbone analysis and algorithm design for the quadratic assignment problem

As the hot line in NP-hard problems research in recent years, backbone analysis is crucial for phase transition, hardness, and algorithm design. Whereas theoretical analysis of backbone and its applications in algorithm design are still at a begin- ning state yet, this paper took the quadratic assignment problem （QAP） as a case study and proved by theoretical analysis that it is NP-hard to find the backbone, i.e., no algorithm exists to obtain the backbone of a QAP in polynomial time. Results of this paper showed that it is reasonable to acquire approximate backbone by inter- section of local optimal solutions. Furthermore, with the method of constructing biased instances, this paper proposed a new meta-heuristic -- biased instance based approximate backbone （BI-AB）, whose basic idea is as follows： firstly, construct a new biased instance for every QAP instance （the optimal solution of the new instance is also optimal for the original one）; secondly, the approximate backbone is obtained by intersection of multiple local optimal solutions computed by some existing algorithm; finally, search for the optimal solutions in the reduced space by fixing the approximate backbone. Work of the paper enhanced the research area of theoretical analysis of backbone. The meta-heuristic proposed in this paper provided a new way for general algorithm design of NP-hard problems as well.