大型活动拥挤踩踏事故BP神经网络安全评估方法应用分析

根据大型活动拥挤踩踏事故是一个极其复杂的多因素、多变量、多层次的人-机-环境系统,利用数学建模的思路,引入人工神经网络评估方法;以沈阳世博会开幕式为例,通过前馈型BP网络训练和测试,将开幕式举办过程中的人员拥挤踩踏事故风险系统划分为人的因素、物的因素、环境因素、管理因素4个子系统和拥挤踩踏事故综合评估总系统,分别对其进行拟合分析,在各个系统的拟合残差满足条件的情况下,得出量化的评估预测值及BP神经网络的使用范围。研究实例表明,BP神经网络评估结果直观易懂,可操作性强,是值得推广运用的一种评估方法。     

Benefits and ancillary costs of natural infrastructure: Evidence from the New Jersey coast

This paper empirically estimates the economic impacts of a large-scale public investment in natural infrastructure aimed at adapting to climate change and increasing coastal resilience. I utilize temporal and spatial variation in investment in dunes to provide a hedonic property value estimate of the economic benefits. I identify the net effect of treatment utilizing the doubly robust Oaxaca-Blinder estimator and show that coastal housing price increases attributable to constructed dunes are approximately 3.6%. A decomposition of the average impact suggests that the policy intervention generates ancillary costs related to impaired ocean views and privacy concerns that partially offset large protection benefits.     

江南丘陵山区农业规模化对水土流失的影响研究综述

农业规模经营是实现农业现代化的重要路径。为了探讨丘陵山区农业规模化发展对于水土流失的影响机理。通过文献综述法梳理相关研究,分析现有研究存在的不足,并提出研究展望。综观前人的研究可以得知:(1)农业规模经营的效益、政策与推动机制等状况;(2)丘陵山区水土流失的影响因素乃为自然因素与人为因素交互作用的结果,以及农业活动对水土流失的影响;(3)水土流失的调查、监测与影响因素的评估方法及仿真模拟。最后,提出5点研究展望:(1)构建丘陵山区水土流失驱动力模型;(2)建立丘陵山区农业规模化对水土流失的影响评估指标体系;(3)甄别影响程度及其时空差异;(4)丘陵山区农业规模化的水土流失效应模拟反演;(5)提出丘陵山区水土资源可持续利用的农业规模化政策建议。以期对我国丘陵山区发展适度农业规模化与可持续发展研究提供科学参考。     

三峡库区新型城镇化进程与社会基础设施建设的协调测度

三峡库区作为长江经济带上特殊的地理单元,其社会基础设施建设与城镇化发展是否匹配,直接影响着库区的长治久安。选取库区2000~2014年的面板数据,构建社会基础设施-新型城镇化测度体系,采用相关性模型对之进行检测,并通过静态协调度模型对15 a间两者的协调度定量分析。测度结果表明:(1)社会基础设施建设与城镇化进程紧密相关;(2)在时间上,库区社会基础设施-新型城镇化测度体系协调度呈协调到失调的发展态势;(3)在空间上,库区不同区县差异明显,需结合具体社会经济发展情况,推进社会基础设施建设与以人为本的新型城镇化的协调发展。     

Socio-technical Systems as Place-specific Matters of Concern: The Role of Urban Governance in the Transition of the Wastewater System in Denmark

In recent years, cities have been portrayed as important loci for transformations of large-scale systems. This paper contributes to scholarship on urban transitions by exploring why the boundaries, functions and challenges of large-scale systems typically are framed differently at the urban level of governance than at more aggregated levels of governance. Empirically, we examine the wastewater system in Denmark by contrasting framings at the urban and national levels over the last 20 years and the transition dynamics that emerged as a consequence of their juxtaposition. The findings illustrate that urban governance of the wastewater system was influenced by a particular concern with developing attractive and competitive urban spaces. The wastewater system emerged as a ‘place-bound’ and even ‘place-making’ governance concern; as such, the boundaries and functions of the system were subject to continuous redefinition at the city level. This urban framing conflicted with the national-level, efficiency-oriented framing of the wastewater system as homogenous, without regard to place-specific differences. The research findings suggest that a distinct characteristic of urban-level governance is concern for place-specific development; this concern can be transformative because it leads to ongoing reinterpretation of traditional boundaries and dependencies between large-scale systems and local contexts.     

Modeling integrated urban water systems in developing countries: case study of Port Vila,Vanuatu

Developing countries struggle to provide adequate urban water services, failing to match infrastructure with urban expansion. Despite requiring an improved understanding of alternative infrastructure performance when considering future investments, integrated modeling of urban water systems is infrequent in developing contexts. This paper presents an integrated modeling methodology that can assist strategic planning processes, using Port Vila, Vanuatu, as a case study. 49 future model scenarios designed for the year 2050, developed through extensive stakeholder participation, were modeled with UVQ (Urban Volume and Quality). The results were contrasted with a 2015 model based on current infrastructure, climate, and water demand patterns. Analysis demonstrated that alternative water servicing approaches can reduce Port Vila’s water demand by 35 %, stormwater generation by 38 %, and nutrient release by 80 % in comparison to providing no infrastructural development. This paper demonstrates that traditional centralized infrastructure will not solve the wastewater and stormwater challenges facing rapidly growing urban cities in developing countries.     

Clashing coalitions: a discourse analysis of an artificial groundwater recharge project in Finland

The purpose of this paper is to increase understanding of the dynamics of knowledge production in the context of large-scale environmental projects causing local conflict. In particular, the paper analyses the discourse coalitions that formed around an artificial groundwater recharge project for the Turku Region in Finland. The material for this study consists of over 400 articles and opinion pieces which were collected from local and regional newspapers between 1999 and 2010. The articles were analysed by using Hajer's [1995. The politics of environmental discourse. Ecological modernisation and the policy process. Oxford, UK: Clarendon] discursive framework, and the analysis was complemented with the concept of knowledge coalition by Van Buuren and Edelenbos [2004. Conflicting knowledge. Why is joint knowledge production such a problem? Science and Public Policy, 31 (4), 289–299]. Results of the study indicate that knowledge coalitions were formed among the researchers, lay residents, and policy-makers, and they all utilised similar expertise-based factual arguments to support their cause. Thus, the paper participates in the academic discussion on the use and interpretation of expert knowledge in environmental policy-making by reshaping the division between experts and lay residents.     

含大规模风电电网综合安全评估模型研究

基于多层次模糊综合评价方法提出了一种含大规模风电电网综合安全评估模型。首先研究了多层次模糊综合评价方法,在充分分析大规模风电注入功率对电网的影响后,综合考虑风电送出水平、电网静态安全性、暂态稳定性和运行经济性多个指标建立大规模风电注入功率对电网影响的评估模型;最后以甘肃酒泉大规模风电基地为实例,仿真分析大规模风电注入对电网的影响,提出适应该风电基地的模糊评价指标、隶属度函数和评语集,对大规模风电注入功率对电网影响的评估模型计算求解,量化评估该风电送出方案,验证了所提出的评估方法的可行性和有效性。     

Food contamination control in European new Member States and associated candidate countries: Data collected within the SAFEFOODNET project

This paper reports the results obtained from the data collected within the European Commission funded project SAFEFOODNET regarding the state of the art in the control of chemical food contaminants in twelve European New Member States and one Associated Candidate Country (Turkey). Information has been gathered on institutions involved in food chemical contamination control, types of contaminants and matrices analyzed, procedures for data quality assurance, purposes of the analyses and accessibility of data in the participant countries. The resulting picture points out the general availability of adequate capabilities for the analysis of food contaminants in the laboratories in charge of control and the performance of the analysis of a large variety of chemicals (persistent organic pollutants, polycyclic aromatic hydrocarbons, pesticides, mycotoxins, heavy metals, radionuclides) in almost each country with few exceptions (dioxins in Bulgaria, Turkey, Latvia, persistent organic pollutants in Lithuania and Malta, polycyclic aromatic hydrocarbons in Malta). The application of validated analytical methods and the process of laboratory accreditation are partially fulfilled within the investigated countries, but still forthcoming for some countries, as in Romania, Turkey and Malta. Information collected on food controls is only partially available online and the language used is prevalently local and English to a lesser extent.