Optimisation algorithms for spatially constrained forest planning

We compared genetic algorithms, simulated annealing and hill climbing algorithms on spatially constrained, integrated forest planning problems. There has been growing interest in algorithms that mimic natural processes, such as genetic algorithms and simulated annealing. These algorithms use random moves to generate new solutions, and employ a probabilistic acceptance/rejection criterion that allows inferior moves within the search space. Algorithms for a genetic algorithm, simulated annealing, and random hill climbing are formulated and tested on a same-sample forest-planning problem where the adjacency rule is strictly enforced. Each method was randomly started 20 times and allowed to run for 10,000 iterations. All three algorithms identified good solutions (within 3% of the highest found), however, simulated annealing consistently produced superior solutions. Simulated annealing and random hill climbing were approximately 10 times faster than the genetic algorithm because only one solution needs to be modified at each iteration. Performance of simulated annealing was essentially independent of the starting point, giving it an important advantage over random hill climbing. The genetic algorithm was not well suited to the strict adjacency problem because considerable computation time was necessary to repair the damage caused during crossover.     

试论我国乡村景观的特点及乡村景观规划的目标和内容

乡村景观是指乡村地域范围内不同土地单元镶嵌而成的嵌块体，以农业特征为主，是人类在自然景观的基础上建立起来的自然生态结构与人为特征的综合体。随着城镇化进程的加快，我国乡村景观将面临着前所未有的变化。如何保护乡村景观的特色和完整性，充分挖掘乡村景观的生态和文化旅游价值，使其形成高效、完整并具有传统特色的多功能的乡村地域，是21世纪乡村可持续发展的重要任务之一。文章首先界定了乡村景观的概念和内涵，指出了我国乡村景观的主要特征；然后探讨了乡村景观规划与土地利用之间的关系，认为乡村景观规划是未来我国乡村持续发展的重要手段；最后系统地讨论了我国乡村景观规划的目标和内容。     

基于GIS的唐山市综合防灾与生态规划

中国北方东部城市正处于高速发展时期，大部分城市由于处于环太平洋地震带和北纬中度灾害带的交叉部位，灾害问题严重，造成的经济损失巨大。因此，为了城市的可持续发展，必须把城市的生态建设和综合防灾工作结合起来，进行整体规划。通过自然灾害数据库的建立，灾害源、工程地质、建筑和城市生命线等数据的ACCESS数据库分别建立起来了。基于数理统计分析模型的GIS技术，以MAPINFO为平台，采用MAPBASIC开发工具，创建了唐山市综合防灾和生态规划信息管理系统，为唐山市的综合防灾的可持续发展规划提供了建议和依据。     

三峡工程移民安置区的环境问题与对策

提出三峡工程移民安置区的主要环境问题，并说明采取的防治对策及措施。     

Meadow management and occurrence of corncrake Crex crex

The aim of this study was to analyse the occurrence of corncrakes in two Swedish meadow sites managed by mowing and grazing, but also with abandoned meadows. Most corncrakes (58%) on meadows were found in unmanaged areas without subsidies to the farmers (i.e. areas with tall vegetation). Several corncrakes (62%) were found in restored areas, managed for less than 10 of the last 40 years, fewer (38%) in areas under continuous management. Vegetation height was negatively associated with number of years of management the last 40 years, and the continuously managed areas were avoided by corncrakes. Sites where corncrake territories occur regularly should be managed to maintain tall vegetation suitable for the species, which requires increased use of mowing. However, the results from our study also suggest that yearly mowing might result in a vegetation structure that is avoided by corncrakes. To achieve a balance between tall grassy vegetation and prevention of succession to scrub a possible management regime would therefore be mowing at intervals of a few years.     

秦皇岛市废矿物油资源化初探

在分析秦皇岛市废矿物油的产生和排放现状的基础上，指出废矿物油资源化是解决近岸海域油污染的最佳条件，并提出了一些可操作性的废矿物油资源化对策。     

略谈奎河的水环境保护与水资源利用

依据奎河水污染的现状和国家对奎河水质要求达到的目标以及奎河流域的经济状况，提出了整治奎河河道及沿岸环境、开发利用奎河水资源，引奎河水入徐沙河，既用于航运又供农田灌溉的奎河水污染综合治及奎河水资源利用方案。除雨季和特大洪灾，奎河污水将不再进入安徽省，较好地解决了奎河的跨省污染问题。     

污水脱氮除磷新工艺研究进展

在参阅大量国内外文献资料的基础上，介绍了城市污水脱氮除磷新工艺——生物倍增工艺和BABE工艺，对这2种新工艺的基本原理、特点及今后的发展动向等作了详细阐述。     

务德镇生态建设规划促进经济与环境协调发展实证分析

论述了生态建设规划的核心内容，要建设领域和重点任务规划几个层面规划内容，调发展。生态功能区区划和重点保护区域、生态分区建设规划、主实证分析证明，生态建设规划促进了务德镇经济与环境协     

异龙湖退田还湖生态建设规划方案研究

异龙湖是云南省九大高原湖泊中人为破坏最严重的湖泊之一，目前湖水水质已超地面水环境质量v类标准，呈现严重的富营养化状态；湖泊沼泽化程度加剧，水供需矛盾突出。论述了异龙湖退田还湖的必要性、退田还湖对水环境的影响以及如何制订切实可行生态建设规划方案。同时对退田还湖移民安置政策进行探讨。