相思树种子的质量评价模型

投影寻踪技术为一种新兴的非线性分析方法,但存在计算过程复杂、编程实现困难等缺陷,鉴于此,我们提出采用模拟退火法直接优化投影寻踪技术的投影函数和投影方向以克服目前投影寻踪技术的种种缺点.在此基础上,提出基于模拟退火法的改进的投影寻踪的相思树种子质量评价模型,利用该模型可把各相思树种批测定指标综合成一维投影值,投影值越大,表示该种批质量越好,根据投影值的大小可对相思树种批样本集进行合理评价.实例质量评价结果表明,直接由样本数据训练的改进投影寻踪林木种子质量评价模型用于相思树种子质量评价简单可行,具有较强的适用性和应用性,可操作性强.基于模拟退火法的改进的投影寻踪法可广泛应用于种子质量评价、群落分类及环境质量评价等研究中各类非线性、高维数据的分级与评价.表1参11     

区域地下水资源承载力综合评价的集对分析方法

集对分析是一种新的不确定性分析方法,针对关于确定-不确定系统给出了分析背景下的联系度表达式,由于其联系度概念具有鲜明的辨证性、完整性,成为处理不确定性问题的独具特色的思想方法。应用集对分析法对关中地区的地下水资源承载力进行了综合评价,评价结果得出:西安地下水资源承载力已达Ⅲ级,该地区地下水资源开发已接近饱和值;咸阳、宝鸡、关中平原、渭南等地区地下水资源承载力属于Ⅱ级,地下水资源开发利用已有相当的规模,但仍有一定的开发利用潜力。评价结果与模糊综合评价、投影寻踪法和物元分析法的结果基本相同。本方法具有概念明确、计算简单,结果合理。该方法为水文水资源的分析、评价提供了一种更为简便的方法。     

基于普通克里格和投影寻踪模型的城市土壤重金属污染评价

作为城市生态环境的重要组成部分,城市土壤对城市的可持续发展具有重要意义。然而,随着人类活动加剧,重金属元素成为城市土壤中具有重大影响的有毒污染物,尤其是铅(Pb)、镉(Cd)、铜(Cu)及其复合物在城市土壤污染中较为突出。为了探讨城市土壤中重金属的含量及污染空间分布特征,为城市环境治理和环境保护提供客观依据,以内江市城区为例,采集了203个表层土壤样本,利用单因子污染指数法、GIS技术结合投影寻踪模型评估了研究区不同土地利用方式下表层土壤铅(Pb)、镉(Cd)、铜(Cu)、锌(Zn)的污染特征及其空间污染程度。结果表明:(1)与国家二级标准限定值比较,镉元素的富集程度最大,锌元素次之,铜元素富集程度最小,铅元素无富集;(2)4种元素变异系数属于高度变异,其含量均受到人类活动的强烈影响;(3)土壤重金属综合污染指数均值表现为公共用地商业用地住宅用地工矿用地农业用地交通用地;(4)内江市城市土壤重金属污染程度的克里格插值评价等级为较清洁、轻污染,在空间展布上二者的面积比例为1.2∶1,内江市重金属综合污染水平较轻。投影寻踪模型为涉及多因素的城市土壤重金属污染评价提供了新思路。     

降水pH值的支持向量回归预测模型构建

将支持向量回归用于降水pH值预测模型的构建,结果表明,该模型具有较好的稳定性和较高的预测精度,降水的pH值主要受大气中碱性离子浓度的影响,起主导作用的是碱性离子的中和作用;其预测结果优于多元线性回归、主成分回归、偏最小二乘回归和投影寻踪回归等模型.     

生态文明视角下城市水安全评价指标体系的构建

水安全既是城市生态文明建设的重要内容,也是生态文明建设的重要保障,而水安全评价则是实现水安全的必然途径。本文旨在以生态文明建设为宗旨,以水安全的影响因素为依据,构建水安全评价指标体系。生态文明导向下的城市水安全评价更强调水资源的循环性、效率性、可持续性,水生态与社会发展的和谐性及平衡性。评价指标体系可分为自然生态、社会行为、制度规则和精神意识4个维度,然后根据每个维度下水资源的特征及外部因素对水资源的影响方式设计具体的评价指标,并运用层析分析法为各指标赋权。     

基于分形插值模型的贵州农产品区土壤养分综合评价研究

以贵州省农产品区为研究对象,选取5个养分指标,利用分形维数权重的方法构建土壤养分分形插值模型,结合GIS技术对贵州省农产品区的土壤养分现状进行综合评价,并引入多种评价模型与分形插值模型评价结果进行验证分析.结果表明:(1)贵州省农产品区中速效钾含量丰富,中位数为162.00 mg·kg~(-1),全氮、有机质、有效磷含量为中等水平,中位数为1.35 g·kg~(-1)、20.30 g·kg~(-1)、10.30 mg·kg~(-1),土壤为微酸性土壤.(2)分形插值是解决复杂的非线性关系问题的模型方法,将其运用于土壤养分综合评价中既考虑了指标间的非线性关系又考虑了指标间的权重关系,通过与投影寻踪模型、熵权TOPSIS模型和数值化模型对比验证与分析,分形插值模型与其他三种模型方法的评价结果有较好的一致性,评价结果更加客观、合理,为土壤养分综合评价提供了一种较好的新方法.(3)土壤养分分形插值综合评价分布图显示,贵州农产品区北部地区较南部地区土壤养分较好,由中部向四周呈放射状递减的趋势,土壤养分各等级水平均有体现,其中等和缺乏水平分布面积占研究总面积的38.17%和36.99%,说明整个研究区土壤养分水平综合状况主要以中等和缺乏水平为主.     

用改进的灰色识别法评价地表水环境质量——以北京石景山区莲花河新开渠为案例

简要论述了利用改进的灰色识别法评价地表水环境质量的计算原理、方法和步骤。改进的灰色识别法以灰色关联法为基础,针对运用灰色关联法对水环境质量进行评价中存在的问题,引入关联离散度和隶属度算法加以改进,并将水环境质量标准等级与相应的隶属度加权平均求得精确水质类别,进一步提高了分辨率和实用性。以北京市石景山区莲花河新开渠为案例,对地表水环境质量进行评价,确定其水质等级以及变化趋势,为水环境保护规划提供科学依据。结果表明:改进的灰色识别法可比性强,分辨率高,具有较高的实用价值。     

基于属性识别理论的城市生态安全评价——以广州市为例

城市生态安全评价可以使管理者和公众及时了解城市发展中生态环境压力的严重态势,为城市可持续发展战略的制定和生态系统的管理提供依据和指导。文章构建了由活力、组织结构、恢复力、生态系统服务功能和人类健康状况5个要素构成的城市生态安全评价指标体系。在有序分割类和属性识别准则的基础上,建立了城市生态安全评价的属性识别模型。采用层次分析法（AHP）和熵权法赋予指标权重,充分利用了主观和客观评价方法的优势。根据此模型对广州市1991—2007年间的生态安全状况进行了实证分析。结果表明城市生态安全状况呈现出,从＂较不安全级＂上升到＂临界安全＂级。在5个评价要素中,除人群健康状况外,其他4个评价要素呈现出逐年改善的趋势。属性识别理论能对事物进行有效识别和比较分析,且原理直观、计算简便、评价结果准确,在评价、预测、决策等领域中具有广泛的适用性。     

基于水文学方法的珠江流域生态流量研究

珠江流域水资源丰富,但由于水体污染等原因,水质性缺水问题较为突出,区域水环境、水生态以及水安全等成为急需解决的重要科学问题。开展生态流量研究对于评价地表水文过程演变对区域水环境与水生态的影响具有重要理论意义,并为区域水资源优化配置和可持续开发利用提供科学依据。基于此,运用各种＂水文学＂方法（包括最小月平均流量法、改进的7Q10法、NGPRP法、逐月最小生态径流计算法和逐月频率计算法）对珠江流域11个主要水文控制站点的实测月径流量做了全面而系统的研究,分析珠江流域生态径流过程,并通过与Tennant法对比分析,选择逐月最小生态径流计算法和逐月频率计算法分别计算了各水文控制站的最小生态径流量和适宜生态径流量,除个别站点外,其评价结果分别处于Tennant法＂中＂和＂最佳＂的等级。对于逐月频率计算法中保证率的选取方法,研究表明各月径流系列均取50%最适合珠江流域。研究同时为仅利用水文资料中的多年逐月径流数据来确定生态需水提供了一种新的研究思路。     

基于蛙跳算法优化的生态环境质量评价的韦伯-费希纳指数公式

为了建立简便、实用的生态环境质量评价模型,在构建生态环境评价指标体系的基础上,设定各指标的参照值和规范变换式,使规范变换后的不同指标同级标准的规范值差异不大。进而提出了一个对多项指标的规范值都适用的生态环境质量评价的韦伯-费希纳(W-F)指数公式。采用混合蛙跳算法对公式的参数进行优化,得出优化后对多项指标皆适用的生态环境质量评价的W-F指数公式。运用该公式对巢湖流域的生态环境质量进行评价,其结果与该流域生态环境质量实际情况基本相符,表明模型有一定的实用性。     

京杭运河徐州段底栖动物与水质的关系

本研究利用生物监测方法，探明了京杭运河徐州段大型底栖无脊椎动物的生物种群及其分布。运用污染生物指数（Ｇｏｏｄｎｉｇｈｔ）和生物多样性指数（Ｓｈａｎｎｏｎ）统计表达，对京杭运河徐州段进行生物综合评价，同时，指出了该水体污染，将给徐州的两个地面饮用水厂及国家南水北调工程带来威胁和危险。通过生物指标与理化指标对比，综合分析研究，冲破了理化指标的限制，说明生物指标对水体污染的评价更全面、可靠而直观。     

Total phosphorus accident pollution and emergency response study based on geographic information system in Three Gorges Reservoir area

• A new algorithm of two-dimensional water quantity and the quality model was built. • The migration and diffusion of TP was simulated. • The emergency measures for sudden water pollution accidents was proposed. In recent years, sudden water pollution accidents in China’s rivers have become more frequent, resulting in considerable effects on environmental safety. Therefore, it is necessary to simulate and predict pollution accidents. Simulation and prediction provide strong support for emergency disposal and disaster reduction. This paper describes a new two-dimensional water quantity and the quality model that incorporates a digital elevation model into the geographic information system. The model is used to simulate sudden water pollution accidents in the main stream of the Yangtze River and Jialing River in the Chongqing section of the Three Gorges Reservoir area. The sectional velocity distribution and concentration change of total phosphorus are then analyzed under four hydrological situations. The results show that the proposed model accurately simulates and predicts the concentration change and migration process of total phosphorus under sudden water pollution accidents. The speed of migration and diffusion of pollutants is found to be greatest in the flood season, followed by the water storage period, drawdown season, and dry season, in that order. The selection of an appropriate water scheduling scheme can reduce the peak concentration of river pollutants. This study enables the impact of pollutants on the ecological environment of river water to be alleviated, and provides a scientific basis for the emergency response to sudden water pollution accidents in the Three Gorges Reservoir area.     

流域水生态系统的生境安全识别理论和方法研究——以太子河次流域本溪段为案例

流域水生态系统具有物质循环、能量流动、群落代谢等服务功能,由于人类活动干扰等因素,水生态系统受到破坏,服务功能的发挥受到抑制。太子河作为中国七大水系之一的辽河支流,其水生态系统健康状况同样由于社会、自然等胁迫驱动力原因受到影响。提出了一套流域水生态系统生境安全识别方法,并以太子河次流域本溪段为案例对方法的可行性进行研讨。采用水文、河道、河岸带和水质4个生境安全指标,分别对研究区的5个评价单元水生态系统生境进行安全评估,做出问题识别,找出水生态系统处于不同健康状态的原因,并确定优先修复项目,便于流域管理。通过研究得到观音阁水库坝区没有优先修复项目,小夹河区、老官砬子-观音阁水库坝区、大峪沟入河口-老官砬子区、兴安市界-大峪沟入河口区优先修复项目分别为河道、河道和河岸带、河道、水质,生境安全识别方法具有一定的可行性。     

Conservation decision-making in large state spaces

When looking for the best course of management decisions to efficiently conserve metapopulation systems, a classic approach in the ecology literature is to model the optimisation problem as a Markov decision process and find an optimal control policy using exact stochastic dynamic programming techniques. Stochastic dynamic programming is an iterative procedure that seeks to optimise a value function at each timestep by evaluating the benefits of each of the actions in each state of the system defined in the Markov decision process.Although stochastic dynamic programming methods provide an optimal solution to conservation management questions in a stochastic world, their applicability in metapopulation problems has always been limited by the so-called curse of dimensionality. The curse of dimensionality is the problem that adding new state variables inevitably results in much larger (often exponential) increases in the size of the state space, which can make solving superficially small problems impossible. The high computational requirements of stochastic dynamic programming methods mean that only simple metapopulation management problems can be analysed. In this paper we overcome the complexity burden of exact stochastic dynamic programming methods and present the benefits of an on-line sparse sampling algorithm proposed by Kearns, Mansour and Ng (2002). The algorithm is particularly attractive for problems with large state spaces as the running time is independent of the size of the state space of the problem. This appealing improvement is achieved at a cost: the solutions found are no longer guaranteed to be optimal.We apply the algorithm of Kearns et al. (2002) to a hypothetical fish metapopulation problem where the management objective is to maximise the number of occupied patches over the management time horizon. Our model has multiple management options to combat the threats of water abstraction and waterhole sedimentation. We compare the performance of the optimal solution to the results of the on-line sparse sampling algorithm for a simple 3-waterhole case. We find that three look-ahead steps minimises the error between the optimal solution and the approximation algorithm. This paper introduces a new algorithm to conservation management that provides a way to avoid the effects of the curse of dimensionality. The work has the potential to allow us to approximate solutions to much more complex metapopulation management problems in the future.     

Sustainable development strategies for China's Du Jiang Yan Water Resources Project

China's Du Jiang Yan Irrigation Project, dating back to 256 BC, is one of the world's earliest water resources projects. Although it has been benefiting the Sichuan Basin area for over 2000 years, it is facing increasing problems due to ecological deterioration, over-exploitation from local industries and agriculture, suboptimal resource allocation arising from supply and demand mismatches, and an aging infrastructure. The traditional water resources development model is no longer appropriate for current and future needs of the area. Therefore, a sustainable development framework is envisioned in which population, economy and environment coexist in harmony. Within this framework, major strategies, such as construction and renovation of infrastructure, promotion of water conserving irrigation through non-engineering measures, pollution control and ecological improvements, restructuring of management entities and exploration of new funding sources, are proposed. An evaluation system is also introduced to assess the degree of sustainability and to monitor progress towards a high level of sustainable development.     

River water quality management model using genetic algorithm

Conventional mathematical programming methods, such as linear programming, non linear programming, dynamic programming and integer programming have been used to solve the cost optimization problem for regional wastewater treatment systems. In this study, a river water quality management model was developed through the integration of a genetic algorithm (GA). This model was applied to a river system contaminated by three determined discharge sources to achieve the water quality goals and wastewater treatment cost optimization in the river basin. The genetic algorithm solution, described the treatment plant efficiency, such that the cost of wastewater treatment for the entire river basin is minimized while the water quality constraints in each reach are satisfied. This study showed that genetic algorithm can be applied for river water quality modeling studies as an alternative to the present methods.     

南昌市生态空间和生态保护红线划定研究

生态保护红线作为生态空间的刚性约束区域,是保障和维护国家生态安全的底线和生命线.结合国土空间规划双评价技术,以南昌市为例,选取水源涵养功能、水土保持功能、水质保护功能、生物多样性保护功能4种重要性指标和土壤侵蚀、酸沉降、水污染3种敏感性指标,采用模型评估法和净初级生产力定量指标评估法,开展生态空间和生态保护红线划定研究...