谈城镇绿化树种的选择与配置

分别从树种选择的注意事项、挑选方法和培植技巧等三方面对树种选择问题进行了探讨,提出了解决城镇绿化树种选择和配置问题的有效方法,为城镇绿化建设工作提供理论支持。     

城乡绿化树种选择分析

文章通过对国内外道路绿化树种现状的分析,探讨了城乡绿化树种选择原则及道路绿化树种选择的主要对策,以期对实践工作起到借鉴作用。     

城乡绿化树种选择分析

文章通过对国内外道路绿化树种现状的分析,探讨了城乡绿化树种选择原则及道路绿化树种选择的主要对策,以期对实践工作起到借鉴作用。     

浅谈大庆地区居住区主要树种的选择及应用

随着人们生活水平的提高,人们对小区内绿化的要求也越来越高,绿化与人们生活质量密切相关,用于绿化的资金投入也越来越多,如何创建优美环境,更好服务小区居民,树种的选择与合理运用显得非常重要,如果买进一些不能生长成活的苗木,就会造成人力、物力、财力的极大浪费,绿化工作需要对当地的气候土壤分区和各种不同树种生态有足够的认识,及时总结出各种树种在生长、管理及绿化应用方面的成功经验和失败的教训。现针对大庆居住区内主要树种进行简单论述,以方便日后工作。     

浅谈樟子松幼苗的培育

樟子松是欧洲赤松的一个地理变种,又名蒙古赤松、海拉尔松,是防风固沙和针叶用材的优良树种。可广泛用于营造防护林、用材林和城镇绿化,是三北地区的主要造林树种。以下探讨了樟子松种子处理、幼苗培育和病虫害防治的育苗技术。     

彩色树种在园林绿化中的应用及发展

目前进行园林绿化建设时,要求越来越高,在绿化、美化、香化的同时,绿化环境的彩化更逐渐成为了新型绿化的重点.本文从彩色树种类型,彩色树种的彩化效果及如何搭配等四个方面进行了介绍,希望大家能够得到借鉴.     

工业厂区典型部位绿化设计实践要要以煤炭企业为例

院以煤炭企业绿化设计为例,选取具有代表性的典型部位,进行绿化形式及树种选择方面的设计要点分析总结,提出立体化的绿化概念以及把应对环境问题视为当务之急的工业厂区环境绿化设计理念     

试论彩色树种在园林绿化中的应用

彩色树种作为特殊的观赏树种,在城市园林绿化中具有重要的作用。对我国彩色树种应用现状、存在的问题进行了探讨,结合地域特点,提出了提高彩色树种应用水平的对策。     

村镇绿化与树种的选择

村镇绿化在树种选择上必须遵循＂因地制宜,适地适树,坚持乡土树种与引进树种并重＂的原则。     

绿化苗木市场畅销

2003年以来,随着城市绿地面积的扩大,城市带状绿化减少,公园式绿化渐渐增加,绿化苗木需求呈现出旺销之势,云南部分乡土树种成为众多商家的抢手货。拟单性木兰国家三级保护濒危品种,具有极高的园林观赏价值,是城市绿化的名贵树种。目前,该树种的市场价格和种子都非常昂贵,胸径在     

试述园林树木养护的措施与方法

随着环境建设的备受重视,各地园林绿化建设步伐的加快,很多好的园林建设已能将人与大自然很好地协调,将历史文化内涵再现出来,对园林设计的各项要求把握得恰到好处,体现出设计者的聪明才智及社会责任感。但是园林树木栽植后,需要良好的养护管理才能保证树木成活和健康地成长发育,达到绿化规划设计的效果。本文从一年养护管理工作的划分、浇水、施肥、整形修剪、病虫害防治、中耕除草、防寒等多方面进行了论述。     

Fifty Years of Classification and Regression Trees

Fifty years have passed since the publication of the first regression tree algorithm. New techniques have added capabilities that far surpass those of the early methods. Modern classification trees can partition the data with linear splits on subsets of variables and fit nearest neighbor, kernel density, and other models in the partitions. Regression trees can fit almost every kind of traditional statistical model, including least‐squares, quantile, logistic, Poisson, and proportional hazards models, as well as models for longitudinal and multiresponse data. Greater availability and affordability of software (much of which is free) have played a significant role in helping the techniques gain acceptance and popularity in the broader scientific community. This article surveys the developments and briefly reviews the key ideas behind some of the major algorithms.     

商洛市行道树选择的探讨

在了解城市行道树选择原则的基础上,以商洛市行道树种为例进行分析,同时对树种的选择进行探讨,并提出了改善商洛市行道树树种的建议。     

沈阳市行道树调查研究

本文主要阐述城市行道树选择的原则及沈阳市行道树应用现状进行分析,并对沈阳市市内五区的行道树进行了调查、分析,提出了改变当前现状,丰富行道树树种的对策和建议。结果表明存在树种单一;常绿树多,落叶树少;行道树的开发利用研究工作十分薄弱等现象,并针对以上问题提出了几点建议。     

邯郸市主城区行道树绿化现状与配置技巧的探讨

行道树是城市园林绿化的骨架,是体现城镇园林绿化水平的重要标志。本文针对邯郸市主城市行道树的绿化现状及其存在的问题,根据行道树树种选择原则和配置技巧的探讨,提出了适合邯郸市生态环境的行道树树种,且对行道树现有的配置方案进行了探讨,提出进一步的优化方式。     

林木种苗生产对策浅析

林木种苗是植树造林的物质基础和希望,在林业和生态建设中具有举足轻重的地位和作用。近几年国家加大了林木种苗投入,重点建设一批林木种苗工程项目,林木种苗生产能力和生产水平得到大幅度提高。同时林木种苗生产社会化的趋势十分明显,全社会各行各业包括外资参与林木种苗生产经营,特别是观赏苗木生产个体生产的比例更高。本文论述林木种苗产业化的技术策略,重点分析了观赏绿化苗木产业化中的品种选择、新技术、新成果的组装配套应用等技术问题。     

DECISION-MAKING IN CONDITIONS OF EXTREME UNCERTAINTY

In the last few years management has been forced to take decisions in conditions of extreme uncertainty. One consequence of this has been an increase in the use of formal methods of analysis in major decision problems. This paper describes some observations on how companies were handling decision-making under uncertainty, made during a S.S.R.C. sponsored research project on the influence of computer methods in planning and decision-making, viz.

• 1 Managers were consciously handling uncertainty by evaluating their major decisions in the light of several possible alternative forecasts.
• 2 Statistical decision theory was not used because, though in theory it was ideally suited for this situation, in practice management had the following objections to the use of this technique: (a) It assumed an accuracy of subjective probability estimates which was unrealistic in real life. (b) It required the use of artificial criteria of choice which were totally unacceptable to senior management. (c) It over-simplified the decision-making process.
• 3 In the thirty-two companies visited, management was using a systems analysis approach to decision-making involving the use of decision trees to structure the decision. Thereafter, instead of carrying out a probalistic analysis, a full evaluation to determine the quantitative and qualitative results would be carried out for each feasible path though the tree. This would be followed by an iterative elimination process.
• 4 Management were also endeavouring to cope with uncertainty by being more adaptive and flexible in their decision-making and are developing contingency or ‘fall-back’ strategies. Plans were not looked on as rigid blue-prints, but more as loosely linked frameworks of decision trees with the actual path through the decision tree dependent on future events.

     

Hyperdeterminantal point processes

As well as arising naturally in the study of non-intersecting random paths, random spanning trees, and eigenvalues of random matrices, determinantal point processes (sometimes also called fermionic point processes) are relatively easy to simulate and provide a quite broad class of models that exhibit repulsion between points. The fundamental ingredient used to construct a determinantal point process is a kernel giving the pairwise interactions between points: the joint distribution of any number of points then has a simple expression in terms of determinants of certain matrices defined from this kernel. In this paper we initiate the study of an analogous class of point processes that are defined in terms of a kernel giving the interaction between 2M points for some integer M. The role of matrices is now played by 2M-dimensional “hypercubic” arrays, and the determinant is replaced by a suitable generalization of it to such arrays—Cayley’s first hyperdeterminant. We show that some of the desirable features of determinantal point processes continue to be exhibited by this generalization.     

浅谈国人心理需求对园林绿化的影响

受到国人心理需求的映射,使得具有红色这一特征的树种在园林绿化中独领风骚,很受广大群众的喜欢,本文初步探讨了在国人心理需求影响下的观红叶、红花、红果树种在园林绿化中的应用及前景展望。     

A nonparametric decomposition of the Mexican American average wage gap

This paper shows that average wage gap decompositions between any two groups of workers can be carried out using nonparametric wage structures. It also proposes an algorithm to correct for sample selection in nonparametric models known as tree structures. This paper studies the wage gap between third‐generation Mexican American and non‐Hispanic white workers in the southwest. It is shown that the decomposition heavily depends on functional assumptions, and that different aproaches to flexibility may render sufficiently good and similar results Copyright © 2008 John Wiley & Sons, Ltd.