Using structured steiner trees for hierarchical global routing

The Steiner problem in a hierarchical graph model, the structured graph, is defined. The problem finds applications to hierarchical global routing. Properties of minimum-cost Steiner trees in structured graphs are investigated. A “top-down” approximate solution to the Steiner problem in structured graphs, called a top-down Steiner tree, is defined, and an algorithm is given to compute such solution. The top-down Steiner tree provides also an approximate solution to the Steiner problem in graphs admitting a structured representation. The properties of such solution are discussed and some experimental results on the quality of the approximation are presented. A reduction in time complexity is demonstrated with respect to both exact and heuristic algorithms applied to such graphs.     

Comparison of Skidding Performance of Small Track-type Experimental Prototype Skidder and J-50 Skidding Tractor

In this paper, field experimental comparison is made between a small track-type experimental prototype skidder and a J-50 skidding tractor. Experimental data, including skidding productivity, soil compaction on skidding trails, and damage rate of the residual trees, are analyzed. The results indicate that with the condition of scattered skidding area and low skidding volume per cycle, small track-type experimental prototype skidder has advantage on working and a higher skidding productivity. It makes lower soil compaction to the skidding trails in the depth of 0-5 cm, 5-10 cm, and 10-15 cm. Under the same work conditions, the damage rate of the residual trees made by small track-type experimental prototype skidder is only 1/5 of those made by J-50 type skidding tractor. The damage rate is reduced by 80%.     

一种基于系数状态表的SPIHT图像编码算法

提出了一种新的基于系数状态表的SPIHT(LPS-SPIHT,list of p ixel stata-set partition ing in h ierarch icaltrees)图像压缩编码算法,该算法具有以下5个特点:第一,定义了一种扩展的空间方向树,使1个结点含有2×2相邻的4个系数,并将基本EZW(嵌入式小波零树)的符号定义应用于扩展树;第二,用1个廉价的系数状态表代替了SPIHT算法中的LIS(不重要集合表)、LIP(不重要像素表)、LSP(重要像素表)等3个数据表,节省了内存;第三,通过扫描系数状态表,可一次性完成对图像数据的编码,使分类过程与细化过程合二而一;第四,利用一种树指数避免了重复计算,提高了处理速度;第五,通过重新组织编码过程,省去了对大量可推知位的编码,提高了压缩效率。实践证明,与目前公认的最为有效的SPIHT算法相比,该算法不仅性能优越,而且计算简单,容易实现。     

Barrier Trees on Poset-Valued Landscapes

Fitness landscapes have proved to be a valuable concept in evolutionary biology, combinatorial optimization, and the physics of disordered systems. Usually, a fitness landscape is considered as a mapping from a configuration space equipped with some notion of adjacency, nearness, distance, or accessibility, into the real numbers. In the context of multi-objective optimization problems this concept can be extended to poset-valued landscapes. In a geometric analysis of such a structure, local Pareto points take on the role of local minima. We show that the notion of saddle points, barriers, and basins can be extended to the poset-valued case in a meaningful way and describe an algorithm that efficiently extracts these features from an exhaustive enumeration of a given generalized landscape.     

钻铣镗类加工中心的概念设计与方案评估研究

提出一种基于多色集合理论的机械产品概念设计的推理算法．采用一个有效的多目标方案评估算法，综合应用了层次分析法、模糊规则和神经网络，对满足需求的方案集进行评估和优化选择，得出满足需求的最优方案．以钻铣镗类加工中心的方案设计为例，用文中方法进行概念设计，得到了能满足需求的方案集和最优方案。     

对合肥市郊县绿化造林的一点看法

对合肥市郊县的绿化造林现状作了分析，提出了切实可行的措施。     

使用计算机生成树木笔绘图形方法的分析

首先对使用计算机生成树木笔绘图形的方法进行了综合介绍,并分析了它具有的优点,及适用的研究对象。进而介绍和讨论了常规的树木图形生成方法,着重阐述了使用计算机自动绘制树木笔绘图形的方法,步骤,关键概念,以及它的应用。最后指出了该方法中存在的不足之处和今后需继续深入研究的方向。     

Intelligent condition monitoring using fuzzy inductive learning

Extensive research has been performed for developing knowledge based intelligent monitoring systems for improving the reliability of manufacturing processes. Due to the high expense of obtaining knowledge from human experts, it is expected to develop new techniques to obtain the knowledge automatically from the collected data using data mining techniques. Inductive learning has become one of the widely used data mining methods for generating decision rules from data. In order to deal with the noise or uncertainties existing in the data collected in industrial processes and systems, this paper presents a new method using fuzzy logic techniques to improve the performance of the classical inductive learning approach. The proposed approach, in contrast to classical inductive learning method using hard cut point to discretize the continuous-valued attributes, uses soft discretization to enable the systems have less sensitivity to the uncertainties and noise. The effectiveness of the proposed approach has been illustrated in an application of monitoring the machining conditions in uncertain environment. Experimental results show that this new fuzzy inductive learning method gives improved accuracy compared with using classical inductive learning techniques.     

复杂有源配电网供电路径快速优化

配电网络结构日益复杂化以及分布式电源广泛接入带来的不确定性,增加了配电网供电路径优化的难度,传统配电网重构方法很难满足其快速性要求。针对风机、光伏出力的波动性,在构造的概率场景模型基础上,基于时间尺度进行出力分割,并利用无重复生成树策略对复杂搜索空间进行简化,避免重复性辐射型校验,减少解空间的冗余度,采取改进的编码策略以及改进的教学优化算法对重构模型进行求解,提高搜索的速度和全局寻优能力。算例分析证明了所提方法的快速性和有效性。     

Understanding Electrical Performance and Microstructure of Water Tree Aged Cables after Silicone Injection during Electrical-Thermal Accelerated Aging

To further understand the long-term effect of rejuvenation fluid on water tree aged cross-linked polyethylene (XLPE) cables after silicone injection, electrical performance and microstructure of water tree aged cables were investigated during an electrical-thermal accelerated aging experiment. Two groups of treated and untreated water tree aged cable samples were subjected to electrical-thermal aging for 2 weeks. The results of the dielectric loss factor showed that the electrical performance of the treated samples was significantly better than that of untreated samples after electrical-thermal aging. Microobservation results showed that the overall water tree sizes of the treated samples were much smaller than those of the untreated samples after electrical-thermal aging. Furthermore, there was a second growth of water trees in the original water tree region during electrical-thermal aging in both groups of samples. Using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), rejuvenation fillers were observed tightly embedded in water tree voids after electrical-thermal aging. The infrared (IR) spectroscopy analysis results showed that the concentration of rejuvenation fluid increased from the outer layer to the inner layer of insulation. Based on the results, due to the improvement of the electric field at the water tree tip and the diffusion of silicone fluid in the insulation layer, both the second growth in the original water tree region and continuing growth at the water tree tip can be effectively inhibited.