可靠性理论在建筑施工安全领域的应用研究

针对建筑施工安全管理体系,从系统可靠性的视角,综合运用可靠性方面的知识,构建了建筑施工安全管理系统混联模型。在此基础上,将可靠性分配理论与故障树分析方法相结合,根据系统安全目标的要求,确定混联系统的第一层次各单元事件的可靠性目标值,对构成各单元的各个下属单元采取最小工作量可靠度分配方法,以此类推,从而建立系统中各单元可靠度再分配量化模型。为便于应用,通过建筑施工过程中常见的脚手架坠落实例,详述系统各单元可靠性分配的计算过程。研究表明,可靠性理论可以成功地应用到建筑施工安全领域;使系统在给定的目标值条件下达到系统的安全性优化,从而实现建筑施工安全保障效能,减小事故损失。     

Multicriteria decision-making for efficient water and land resources allocation in irrigated agriculture

The irrational use of water in agriculture is often responsible for several problems concerning the depletion and/or the pollution of water resources. In these cases specific policy measures should be taken to protect water resources from harmful agricultural activities, mitigating at the same time their potential impact on farmers’ welfare. To this end, a multicriteria decision-making model is formulated that aims at allocating efficiently water and land resources in a rural area of Greece, by optimizing a set of important socio-economic and environmental objectives. According to the model’s output, past and current decisions on irrigated agriculture turned out to be oriented towards meeting exclusively the socio-economic objectives. Yet, there are several other possible allocations schemes that could be applied in order to improve the performance of environmental indicators and to contribute to a more sustainable use of natural resources. Moreover, the decision-making model can be further employed to assess a number of additional policy measures in irrigated agriculture. In this framework, the outcome of imposing various water pricing policies was evaluated. The efficiency of these policies was found tightly connected to the elasticity of water demand. Namely, higher elasticity seems to enhance the flexibility in resource allocation and the movement towards environmental objectives. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

常州市太湖流域水环境质量目标管理技术研究——控制单元水环境容量分配方法研究

本研究在控制单元划分的基础上,构建了控制单元内水环境容量三层分配体系。逐层建立评价指标体系,运用综合权重法逐层分配水环境容量。实现了不同类型污染源之间、不同点源之间的水环境容量分配,结合污染源排放现状,得出不同类型污染源及不同点源的污染负荷削减量,为水环境管理提供决策支持。     

Enhanced nitrogen deposition exacerbates the negative effect of increasing background ozone in Dactylis glomerata, but not Ranunculus acris

The combined impacts of simulated increased nitrogen (N) deposition (75 kg N ha⁻¹ yr⁻¹) and increasing background ozone (O₃) were studied using two mesotrophic grassland species (Dactylis glomerata and Ranunculus acris) in solardomes, by means of eight O₃ treatments ranging from 15.5 ppb to 92.7 ppb (24 h average mean). A-C_i curves were constructed for each species to gauge effects on photosynthetic efficiency and capacity, and effects on biomass partitioning were determined after 14 weeks. Increasing the background concentration of O₃ reduced the healthy above ground and root biomass of both species, and increased senesced biomass. N fertilisation increased biomass production in D. glomerata, and a significantly greater than additive effect of O₃ and N on root biomass was evident. In contrast, R. acris biomass was not affected by high N. The study shows the combined effects of these pollutants have differential implications for carbon allocation patterns in common grassland species.     

土地整理对区域蓝绿水资源配置的影响

绿水是流域内对植物和生态有积极作用的水量,是通过蒸散发流向大气圈的水汽流.绿水概念的提出有助于强化人类对自然界生态需水的重税.论文分析了大尺度水文循环中绿水流的影响因素,阐述了绿水资源对维持全球生态系统服务功能的积极意义.论文以土地整理过程为研究对象,按照水资源配置的公平性要求,构建符合土地整理特点的蓝绿水资源配置模型.模型综合考虑了蓝绿水生成机理、区域水权配置原则、上下游水量传输规律及区域水量配置方法等关键技术.最后以湖北省武汉市新洲区汪集街孔埠新农村试点土地整理工程为实例,对该区域蓝绿水配置情况进行深入研究.结果表明,土地整理中的土地利用/覆被变化影响区域耕地结构和生态系统服务价值,从而改变区域蓝水和绿水配置权值,实施区域内的人胜村、姚堤村、程山村的蓝绿水配置水量分别增加74 799 m<'3>/a、779 m<'3>/a、21 539 m<'3>/a,而堤围村、吴河村则分别减少了14 372 m<'3>/a、12 745 m<'3>/a.     

Allocation of Streamflow Depletion Impacts under Nonlinear Conditions

A method is proposed for the equitable allocation of impacts of groundwater pumping on streamflow. The method is intended for cases in which the pumping activity of multiple entities has impacts on streamflow and these impacts are computed by perturbation. It is shown that when the response of streamflow to pumping is nonlinear, simple methods for impact calculation can fail. The proposed method is developed for the case when there are four entities that impact streamflow. The method relies on the calculation of impacts by perturbation of the simulation model from different base pumping levels. When four entities are evaluated, 16 runs of the simulation model are required. It is shown the proposed method produces estimated impacts for each individual entity that are equitable because they meet the requirement that the impacts of each entity sum to the total impacts of all entities acting together and the impacts attributed to each entity do not depend on the order of calculation. A brief example demonstrates the approach.     

Water Prism: A Tool to Assess Water Availability Risk and Investigate Water Management Strategies

Water availability risk is a local issue best understood with watershed‐scale quantification of both withdrawal and consumptive demands in the context of available supply. Collectively, all water use sectors must identify, understand, and respond to this risk. A highly visual and computationally robust decision support tool, Water Prism, quantitatively explores mitigation responses to water risk on both a facility‐level and basin‐aggregated basis. Water Prism examines a basin water balance for a 40‐ to 60‐year planning horizon, distinguishes among water use sectors, and accounts for ecosystem water needs. The 2012 Texas State Water Plan was used to apply Water Prism to the Big Cypress‐Sulphur Basin (Texas). The case study showed Water Prism to be an accurate and convenient tool to provide fine‐scale understanding of water use in the context of available supply, evaluate multi‐sector combinations of conservation strategies, and quantify the effects of future demands and water availability. Analyses demonstrated water availability risks for rivers and reservoirs can vary within a basin and must be calculated independently, simulation of water balance conditions can help illuminate potential impacts of increasing demands, and scenario simulations can be used to evaluate relative conservation efficacy of different water resource management strategies for each sector. Based on case study findings, Water Prism can serve as a useful assessment tool for regional water planners.     

Effects of economics and demographics on global fisheries sustainability

A good understanding of social factors that lead to marine ecological change is important to developing sustainable global fisheries. We used balanced panel models and conducted cross‐national time‐series analyses (1970–2010) of 122 nations to examine how economic prosperity and population growth affected the sustainability of marine ecosystems. We used catches in economic exclusive zone (EEZ); mean trophic level of fishery landings (MTL); primary production required to sustain catches (expressed as percentage of local primary production [%PPR]); and an index of ecosystem overfishing (i.e., the loss in secondary production index [L index]) as indicators of ecological change in marine ecosystems. The EEZ catch, %PPR, and L index declined gradually after gross domestic product (GDP) per capita reached $15,000, $14,000, and $19,000, respectively, and MTL increased steadily once GDP per capita exceeded $20,000. These relationships suggest that economic growth and biodiversity conservation are compatible goals. However, increasing human populations would degrade marine ecosystems. Specifically, a doubling of human population caused an increase in the %PPR of 17.1% and in the L index of 0.0254 and a decline in the MTL of 0.176. A 1% increase in human population resulted in a 0.744% increase in EEZ catch. These results highlight the importance of considering social and economic factors in developing sustainable fisheries management policy.     

中国“十三五”时期省际碳减排目标的效率分配

首先,将"零和收益"的博弈思想引入到SBM模型中,构建了基于零和收益的碳减排SBM效率分配模型(ZSG-SBM)。然后,基于"十三五"规划中我国整体碳强度降低18%的减排约束,从经济增速和能源消费结构2个维度设置了"十三五"期间我国经济系统的4种发展情景,应用上述ZSG-SBM模型对碳减排目标进行了省际层面的效率分配。并通过对比各省经济发展现状和碳减排目标的分配结果,分析了各省的低碳经济发展路径。结果表明:采用ZSG-SBM模型对碳排放量进行效率分配后,30个省份的投入、产出指标实现了有效配置,碳排放效率到达效率前沿。政府基于"公平"导向的行政分配方案会造成一定程度的效率损失,基于ZSG-SBM模型的效率分配方案更符合低碳经济的长远发展要求。在碳强度约束的基础上,能源强度的再约束将迫使各省优化能源消费结构,从而提升我国整体碳排放效率。"十三五"时期,我国有16个省份的碳减排目标分配结果大于18%的平均标准,各省应根据自身资源禀赋、经济水平、产业结构和能源消费结构的现状选择差异的低碳经济发展道路。     

Grid extension in German backyards: a game-theory rationale

A substantial extension of the electricity grid seems to be necessary in Germany in the coming decades for technical, economic, and ecological reasons. The increased usage of electricity from environmentally conscious sources is not undisputed and the question of where and how to extend the grid is at the centre of a controversial public discussion. One crucial point in this discussion concerns the fair sharing of the costs and benefits of such an extension. It is necessary to create a fair compensation mechanism. Therefore, an innovative mechanism is proposed in this paper that consists of cooperative game theory as well as auction elements. We interpret the German grid extension as a cooperative cost reduction game that allows the identification of fair cost shares and compensation payments. To solve the problem of non-cooperative behaviour, we propose the involvement of a sealed-bid auction. We show that this novel procedure is incentive compatible.