两类图的笛卡尔积图的临点可区别关联色数

图的关联着色问题是图着色理论的重要组成部分之一,确定图的关联色数是一个具有很大挑战性也非常有意义的课题。非常图的关联色数同图的强色指数有密切的关系,本文给出了路与路的笛卡尔积图和路与完全图的笛卡尔积图的邻点可区别关联色数。     

两类幂图的强边染色

图的强边染色是在正常边染色的基础上,要求每个色类的导出图是一个匹配。本文通过构造法,研究了路的幂图的强边色数至多是9,圈的幂图的强边色数至多是14。     

Halin图的邻点可区别全染色

一个正常的全染色满足相邻顶点的顶点及其关联边所用的色集合不同时,称为邻点可区别全染色,其所用的最少的颜色数称为邻点可区别全色数,本文刻画了Halin图的邻点可区别全色数。     

偶图中相互独立的4-圈和6-圈

设k≥3是一个正整数,G=(X,Y;E)是一个顶点数为4k的偶图,且有||X=||Y=2k。设δ(G)≥k+1,则图G包含k-3个4-圈,1个6-圈和一条含6个顶点的路,且它们是相互独立的。     

全站仪对边测量测绘线路横断面图

以SET 2 110型全站仪为例 ,讨论了利用全站仪的对边测量功能在线路横断面图测绘工作中的应用方法。     

多弦圈的优美性

Bodendiek,Schumacher和Wegner猜想:每个带有一条弦的圈都是优美的。这个猜想在文[4]中得到了证明。K.M.Koh,D.G.Roges,H.K.Teo和K.Y.Yap证明了,每个带有两条连贯弦的圈都是优美的。K.M.Koh和N.Punnim又进一步地证明了每个带有3条连贯弦的圈也都是优美的。在本文中,我证明了,某些带有更多弦的圈,即C_(4s)(r),C_(4·2t)(k_0,k_1,…,K_t)都是优美的。     

特殊图的一般邻点可区别全染色

根据图的结构性质,利用穷染、置换的方法,研究了两类特殊图的一般邻点可区别全染色,给出了图的一般邻点可区别全色数指标。     

直角坐标机器人灭火系统研究

针对电信机房、数据存储中心等区域,设计了一种直角坐标机器人灭火系统。结合热释电传感器和摄像监视系统实现火源的精准定位,利用多目标模拟退火算法优化机器人行进路径,实现火灾的快速扑灭。在密闭机房内进行模拟实验,验证灭火系统的性能。实验结果表明：所设计的直角坐标灭火机器人在行进中不会出现位移冲突,且能够根据火源位置寻找到最优灭火路径,实现快速高效灭火。     

混凝土彩瓦着色工艺的对比分析

近几年混凝土彩瓦已成为我国城市坡屋面材料选用的主流产品之一,但一些屋面的彩瓦使用才二三年,甚至不到1年就出现褪色、掉色等现象。文中就混凝土彩瓦的不同着色工艺及其对质量、寿命的影响进行比较分析。     

燃气隧道窑砖之焙烧着色初探

利用焙烧使砖呈现不同颜色 ,从古至今 ,基本属于一种技巧 ,如利用土窑烧制青砖 ,太平洋公司为烧制青砖也曾从河南请来师傅 ,并指导笔者先后建了四座土窑 ,有两座至今仍可正常使用。然而随着科学技术的不断进步 ,靠人工操作的技巧使砖着色已发展成为一种能适当控制的技术 ,如在燃气隧道窑中引用“纯净燃气”烧嘴 ,对砖进行“表面玻化”着色或“局部还原”着色 ,均已获得成功 ,表面镶色 (Flashed)产品 ,已为砖产品增添了新的一族。笔者在介绍太平洋砖厂隧道窑的系统组成时 ,曾简略地提起还原系统 ,现将其基本原理及实际应用效果再作一较详细…     

利用二氯化铁的氧化反应改色花岗石的研究

利用二氯化铁高温氧化反应,对普通灰白色花岗石进行了改色研究。考察了花岗石改色的主要影响因素,确定了较理想的工艺条件,并对改色后的花岗后时行了性能测试。测试结果表明,本方法改色的花岗石耐酸、耐碱、耐有机溶剂、耐沸水、耐紫外光。     

Applying Directed Acyclic Graphs to Assist Specification of a Hedonic Model

This research empirically tests the hypothesis that utilizing directed acyclic graphs (DAGs) as an ex-ante process to select variables for a hedonic model improves the model's performance. The results for both new and existing house submarkets indicated that DAG analysis mitigated the multicollinearity issue commonly observed in hedonic models. Using DAG analysis also improved the goodness-of-fit of the hedonic model for the new submarket. However, model specification through DAG analysis does not offer clear implications for improving forecasting accuracy, efficiency, and spatial error autocorrelation. The findings imply that DAG analysis for model specification can be a complementary step in the process of estimating hedonic models, especially when reducing standard error bias by alleviating potential multicollinearity is important in determining the attributes that affect housing prices.     

Hydro-ecological implications of edge cities

A spatial and temporal classification of the embryonic forms of edge cities within their physical/environmental context is developed. Three classes of edge cities are identified as having developed along the expressway system: (1) transportation/service; (2) transportation/service/commercial; and (3) corporate/industrial. Each edge-city class has special implications for the hydro-ecological environment. A case study was used to assess the effects on these three classes on several basic indicators of impacts from stormwater runoff, groundwater contamination, and habitat fragmentation. The results indicate that transport/service edge-cities may pose a significant threat of contamination to the groundwater resource owing to the existence of underground storage-tanks and the transport of hazardous substances. In transport/service/commercial edge-cities, runoff volumes increase dramatically and water quality declines, as development displaces wetlands and creates impervious land cover. At a corporate/industrial edge-city location, habitat fragmentation is higher, as reflected by a decreased patch size for forest and wetland areas.     

Geocomposite edge drain joining

The integrity of the joints that connect all of the various components of a geocomposite edge drain system plays a significant role in the performance of the system. This paper reviews the need for edge drains, describes what they are and discusses the key performance requirements of the joints of an edge drain system. The geotextile seams, roll-to-roll splices and outlet system connections are the critical joints. These assemblies must remain sealed from soil infiltration and free of flow restrictions both after installation and throughout the edge drain systems' design life.