基于TOPSIS模型的土地整理项目综合效益评价研究

本文在分析现代意义土地整理效益评价理论内涵的基础上,通过对整理区现状基础资料及土地整理相关资料收集并进行系统的分析,从经济效益、社会效益、生态效益三个方面选取了15个评价指标,建立了一套土地整理效益评价指标体系。利用层次分析法确定其权重,运用TOPSIS模型对内蒙古自治区3个井灌土地整理项目进行实例分析,实例分析结果表明:3个土地整理项目综合效益实施结果塔布赛乡整理项目实施综合效益为0.8,伍什家镇整理项目实施综合效益为0.64,双河镇整理项目实施综合效益为0.56,从土地整理实施综合效益等级上划分,塔布赛乡土地整理项目达到优秀等级,伍什家镇土地整理整理项目、双河镇土地整理项目效益良好。     

An organizational model and border port hinterlands for the China-Europe Railway Express

Facilities connectivity is a priority area for implementing the Belt and Road Initiative (BRI). The “China-Europe Railway Express” (CER Express) mode of transport organization links China with Europe by fast-track cargo rail. A major instance of facilities connectivity related to this project is an important practical and symbolic instance of BRI transport cooperation. The strategic significance of the CER Express and a number of operational issues are outlined, as are the implications of limited market potential for costs and competitiveness. A “hub-and-spoke” organizational model that can generate scale economies and reduce costs is proposed. To examine the establishment of an organizational model of this kind, the economic hinterlands of Alashankou, Erenhot, and Manzhouli are identified under high-, mediumand low-cost scenarios using an analytical methodology that determines distance and economic costs, and a number of transport hubs (that include Harbin, Zhengzhou, and Lanzhou) are identified. The results found that the cost of the routes from 314 Chinese cities to Moscow is the lowest via Manzhouli in the high- and medium-cost scenarios, but the routes change via Erenhot in the low-cost scenario. A number of policy recommendations should follow up.     

Preferential flow: first results of a full-scale flow model

The main goal of a joint project undertaken by the geophysical and hydrological research units of Kiel University is to study preferential flow in a large open-air, full-scale model, looking in particular at near-surface penetration and flow of water through the unsaturated vadose zone. An artificial irrigation device is installed in place of natural rain, and a homogeneous sand body is used instead of natural soil. This provides a reference model for future field experiments. Inside the sand body there are a large number of geophysical and hydrological sensors to measure DC resistivity (using various electrode configurations), water content and water potential (using TDR and tensiometer instruments, respectively). A ground-penetrating radar (GPR) system is installed at the surface, whereas at the bottom several containers and a thin gravel layer are embedded to measure the flow arrival and the discharge of water. Irrigation is varied in intensity, time, area, and salt content (tracer).
  Results of the first six experiments show that the percolation of intruding water can be followed by all techniques and percolation is finally controlled by the discharge measurements. These display some undulations and variations of the water 'front' and agree with the measurements of all other sensors. The redundancy achieved by the use of multiple methods was intended to enable an assessment of the reliability of the techniques used. The true values of electrical resistivity before and after irrigation reflect the distribution of water saturation within the sand body. A numerical 3-D inversion of the apparent resistivity provides information regarding future field experiments, in which it will be possible to install only some of the sensors in order to preserve the natural structure of the soil.     

拉萨地区土地利用变化情景分析

根据西藏拉萨地区1990年、1995年和2000年3个时点的土地利用数据,应用马尔科夫过程模型分析了未来20年内拉萨地区的土地利用情景变化,并与90年代制定的拉萨地区土地利用规划面积进行了对比研究。研究结果:1)10年间,土地利用类型变化最广泛的是牧草地。变化方向主要由牧草地向耕地、园地、林地、居民点及水域转变,其中变成林地的面积最大,为2338.25hm²(占变化面积的94.093%);2)拉萨地区未来20年中土地利用类型发展趋势是耕地、牧草地、水域和未利用土地面积将进一步减少,林地、园地和居民点面积将进一步增加;3)土地利用规划面积与基于马尔科夫模型的土地利用变化情景分析结果比较吻合,马尔科夫过程模型对制定该区域土地利用规划具有重要的参考价值;4)由于土地利用变化是一个复杂的过程,不仅受到众多自然因素的影响,而且受到未来土地利用政策、社会经济发展、区域内大型工程项目及其他人类活动等不确定因素的影响,从而不同土地利用类型之间的转移概率会发生变化,使得基于马尔科夫过程模型预测的精度有一定的局限性。     

Uncertainties in the SNOWPACK multilayer snow model for a Canadian avalanche context: sensitivity to climatic forcing data

Abstract

As interest in outdoor activities in remote areas is increasing, there is a strong need for improved avalanche forecasting at the regional scale. Due to important logistical and safety matters, avalanche terrain measurements (avalanche observations, snowpack profiles, and stability tests) are not always possible for practitioners/forecasters. An interesting alternative would be to analyze the snowpack without these challenges by using snow model outputs. The SNOWPACK model is currently used operationally for avalanche forecasting and research in the Swiss Alps. Thus, this paper presents a summary of analyses that have been conducted to assess the potential of using the SNOWPACK model driven with both in-situ and forecasted meteorological data in three different Canadian climate and geomorphological contexts. A comparison of meteorological data from in-situ and predicted datasets for two winters shows that the GEMLAM weather model is the most accurate for the three climatic contexts of this project, but also showed a bias proportional to precipitation intensity/rate. Snow simulations forced with GEMLAM are the closest to field measurements. Finally, predictions of persistent weak layers have been validated using the InfoEx platform from Avalanche Canada. Crust and surface hoar formation dates agree with the information reported in InfoEx.     

3-D magnetotelluric inversion and model validation with gravity data for the investigation of flood basalts and associated volcanic rifted margins

20 magnetotelluric (MT) soundings were collected on the Isle of Skye, Scotland to provide a high-resolution three-dimensional (3-D) electrical resistivity model of a volcanic province within the framework of a project jointly interpreting gravity, seismic, geological and MT data. The full 3-D inversion of the MT data jointly interpreted with gravity data reveals upper crustal structure. The main features of the model are interpreted in conjunction with previous geological mapping and borehole data. Our model extends to 13 km depth, several kilometres below the top of the Lewisian basement. The top of the Lewisian basement is at approximately 7–8 km depth and the topography of its surface was controlled by Precambrian rifting, during which a 4.5 km thick sequence of Torridonian sediments was deposited. The Mesozoic sediments above, which can reach up to 2.2 km thick, have small-scale depocentres and are covered by up to 600 m of Tertiary lava flows. The interpretation of the resistivity model shows that 3-D MT inversion is an appropriate tool to image sedimentary structures beneath extrusive basalt units, where conventional seismic reflection methods may fail.     

非特色型产业扶贫模式及其对乡村振兴的启示

探讨了产业扶贫参与主体及其影响因素的互动关系,阐释了产业扶贫促进乡村振兴的机理,在此基础上剖析了非特色型产业扶贫案例——德青源金鸡产业扶贫模式,总结了相关扶贫经验及其对乡村振兴的启示.结果表明:(1)产业扶贫通常涉及政府、企业、被帮扶农户、金融机构/投资管理平台、科研机构等多个参与主体,其发展模式受社会、经济、地理、政...     

生态建设工程中利益主体间的博弈模型——以政府主导的退耕还林还草工程为例

在政府主导的生态建设工程中,各利益主体决策行为相互影响,策略相互依存。使用博弈论方法研究生态建设工程中利益主体间相互作用关系及结果是一条可行途径。以典型的生态建设工程——退耕还林还草工程为例,分别从静态和动态两方面,建立退耕还林还草博弈模型。模型表明:在中央政府参与的三方动态博弈中,中央政府应当在发展水平较低、生态环境脆弱地区安排下达较多的任务量,同时为保证项目工程顺利实施,应提高该地区的补助比例;在没有中央政府的监督考核机制、群众完成项目量不影响地方政府外部效应情况下,地方政府就会忽视群众利益;农牧民作为项目具体执行者,主要从政府补助比例、工程任务量及自身实际情况出发,考虑完成任务比例,而极少关注政府"信誉"问题。因此,在推进生态建设工程中,项目决策管理层应认识到地区间差异,实行有区别的项目政策,中央政府应在工程中起主导作用。     

秦巴山区中山地小流域土地持续利用模式探讨--以柞水县薛家沟流域为例

在分析薛家沟流域土地利用现状、持续利用条件和限制因素的基础上 ,依据流域立体分异特性 ,提出川平地以粮食种植、坡地以经济果木和防护林为主导的山地林果药菌立体开发的土地利用模式     

The Network-Max-P-Regions model

This paper introduces a new p-regions model called the Network-Max-P-Regions (NMPR) model. The NMPR is a regionalization model that aims to aggregate n areas into the maximum number of regions (max-p) that satisfy a threshold constraint and to minimize the heterogeneity while taking into account the influence of a street network. The exact formulation of the NMPR is presented, and a heuristic solution is proposed to effectively compute the near-optimized partitions in several simulation datasets and a case study in Wuhan, China.     

生态省建设的碳减排效应研究

自1999年以来,中国开始生态省建设试点,探索加强生态环境整体性治理之路。生态省建设作为国家改善生态环境的重大举措,是否对二氧化碳排放产生影响是一个值得深入研究的问题。本文利用2000—2015年中国省级面板数据,采用准自然实验方法,构建双重差分模型,考察和评估了生态省建设的碳减排效应。研究发现：生态省建设不仅可以提高生态环境治理质量,而且具有显著且稳健的碳减排效应;生态省建设的碳减排作用主要是通过经济阻碍效应、生态保护效应及产业结构效应实现;生态省建设虽然对减少碳排放取得一定的成效,但依然存在区域建设不平衡,生态产业发展落后,生态创新、技术进步乏力等有待解决的问题。本文可为更好地推广生态省建设经验、提高生态省建设的碳减排效应提供科学依据。     

Urban policy mobilities,argumentation and the case of the model city

In recent years urban geographers have devoted considerable attention to the dynamics of policy mobility. After reviewing the progress achieved in this literature, in this article I offer two distinctive contributions. First, I draw on the “argumentative turn” in policy studies and related fields in order to develop an alternative conceptualization of urban policy mobility that pays greater attention to its discursive and argumentative aspects. I thus reassert the significance of democratic processes in the negotiation of urban policy. Second, I outline an alternative methodology for the study of urban policy mobility, focusing on the analysis of argumentation. I apply this methodology to historical instances of urban policy mobilities arising from a recent research project that aimed to historicize the phenomenon of the “model city,” defined as the local deployment of another city’s experience as an argumentative resource supporting particular policy claims.     

Development and Implementation of a Bayesian-based Aquifer Vulnerability Assessment in Florida

The Florida Aquifer Vulnerability Assessment (FAVA) was designed to provide a tool for environmental, regulatory, resource management, and planning professionals to facilitate protection of groundwater resources from surface sources of contamination. The FAVA project implements weights-of-evidence (WofE), a data-driven, Bayesian-probabilistic model to generate a series of maps reflecting relative aquifer vulnerability of Florida’s principal aquifer systems. The vulnerability assessment process, from project design to map implementation is described herein in reference to the Floridan aquifer system (FAS). The WofE model calculates weighted relationships between hydrogeologic data layers that influence aquifer vulnerability and ambient groundwater parameters in wells that reflect relative degrees of vulnerability. Statewide model input data layers (evidential themes) include soil hydraulic conductivity, density of karst features, thickness of aquifer confinement, and hydraulic head difference between the FAS and the watertable. Wells with median dissolved nitrogen concentrations exceeding statistically established thresholds serve as training points in the WofE model. The resulting vulnerability map (response theme) reflects classified posterior probabilities based on spatial relationships between the evidential themes and training points. The response theme is subjected to extensive sensitivity and validation testing. Among the model validation techniques is calculation of a response theme based on a different water-quality indicator of relative recharge or vulnerability: dissolved oxygen. Successful implementation of the FAVA maps was facilitated by the overall project design, which included a needs assessment and iterative technical advisory committee input and review. Ongoing programs to protect Florida’s springsheds have led to development of larger-scale WofE-based vulnerability assessments. Additional applications of the maps include land-use planning amendments and prioritization of land purchases to protect groundwater resources.     

Estimation of Mining Project Values Through Real Option Valuation Using a Combination of Hedging Strategy and a Mean Reversion Commodity Price

Cash flows generated from mining projects are typically highly volatile and significantly influenced by a number of exogenous factors including commodity price as one of the most influential uncertainties. In addition, mining projects are complex and many of their executed investment decisions are irreversible. Therefore, management needs to address this potential risk exposure before making an investment decision. Due to the deterioration and fluctuation of mineral commodity prices for a successful mining project acquisition or development, an important and appropriate investment strategy should include a hedging strategy for reducing potential losses suffered by a company. The discounted cash flow methods, which are commonly used to calculate mining project values, often fail to respond to this identified economic uncertainty and also to incorporate de-risking hedging strategies. Therefore, this study approximates the numerical value or value ranges of a mining project considering the combination of a mean reverting commodity price and hedging strategies using continuous time modeling. A novel time-dependent partial differential equation has been proposed using a continuous time, mean reverting model, and hedging strategy to approximate the mining project value. Application of a new real options valuation technique demonstrated its superiority by providing the advantage of mitigating financial losses and procuring financial gains. In this study, some key results are deferral option and expansion option enhanced the maximum values of the project which are, respectively, 2.51 % and 4.4 % compared to the base case. Furthermore, the country risk has a great impact on project values, as when we considered the country risk premium is zero in our model, the project value increases up to 0.97 %.     

基于模糊故障树法的深基坑支护工程项目风险评估

深基坑工程施工中安全事故的发生给社会及施工企业带来了不良影响和巨大的经济损失,如何减少深基坑工程安全事故发生率,降低工程风险是一个值得研究的问题。本文通过将模糊理论与故障树分析方法相结合,建立了基于模糊故障树法的深基坑支护工程项目风险评估模型,克服了传统故障树方法忽略底事件发生概率的不确定性这一缺陷。通过对某深基坑工程实例的计算分析,说明了本文所建立的模型在深基坑工程风险评估中具有较好的理论价值与实际应用价值。     

基于多主体模型的典型区域退耕还林工程实施空间模拟

土地利用变化是全球变化的重要驱动力,模拟是研究土地变化重要的方法。退耕还林是中国山区土地利用变化的重要原因。当前退耕还林模拟在综合社会与空间途径方面的不足限制了退耕还林模拟的空间精度及后续社会效益研究。结合社会和空间途径精确模拟退耕还林的空间过程可为该工程实施提供科学依据。本文以云南省东川区铜都镇为研究区,基于人口普查数据、地理环境数据、实地调研数据,综合考虑农民、农户和政府3类主体,基于多主体模型构建了退耕还林工程实施的空间模型,模拟了2010—2015年铜都镇具有空间特征的农户年收入、农户/政府退耕意愿和退耕还林工程空间实施过程。研究发现退耕还林工程实施主要与坡度、交通和农户收入有关,与土壤肥力相关性较小,坡度25°~30°的耕地占了81.47%,离道路0~2 km交通条件较好的地段占56.37%,农户年收入较低的区域退耕还林比例较高,且退耕还林工程的实施显著提高了铜都镇收入,2010—2015年户均收入提高了1475元。本文模拟结果空间精度为91.12%。本文构建的退耕还林工程实施空间模拟方法可为其它区域提供方法借鉴,以期为中国生态保护和精准扶贫等工程实施提供科学支撑。     

GEO-Teach: A Preservice Teacher Preparation Program in Geography

Abstract

GEO-Teach is a project funded by the Fund for the Improvement of Preservice Education (FIPSE). The project aims to develop a model preservice curriculum at the secondary level. It incorporates the newly published National Geography Standards and merges content with pedagogy through partnerships with faculty in education and other social and behavioral sciences to deliver the curriculum. School teachers act as mentors to students in the program.     

轨道交通对其沿线商品住宅价格的影响分析——以北京地铁5号线为例

以北京地铁5 号线为例,研究了地铁沿线两侧2 km范围内,轨道交通对其沿线商品住宅价格的影响程度。① 通过分析商品住宅价格特性和影响因素,建立了轨道交通沿线商品住宅价格的影响因素体系,包括商品住宅项目距最近地铁站的最短路径距离、距市级商服中心距离、周边1 km内公交站点数、中小学及项目容积率、物业类型等10 个因素;② 通过显著性检验,重点中小学、普通中小学、公园3 个变量对商品住宅的价格影响很小,予以剔除后,构建了影响商品住宅价格的多元回归分析模型;③ 将采集到的193 个项目的有效样本进行运算分析,研究结果表明轨道交通对沿线商品住宅价格的影响最大,并随距轨道交通距离的增加,住宅价格呈指数衰减,至2 km以后,对住宅价格影响不显著。针对研究结果,建议地铁沿线土地利用强度和住宅价格确定时,要充分考虑轨道交通的影响。     

基于资源环境承载力的合肥市增长边界划定

在快速城市化和主体功能区战略背景下,滨湖城市作为城湖共生体,具有湖泊生态系统和城市社会经济系统双重属性,既是中国新型城市化格局中最具活力和潜力的核心单元之一,又是湖泊生态环境问题集中激化的高度敏感区,保护与开发并重,发展与风险共存。以行政区划调整后将巢湖纳入内湖的新合肥市为例,借助GIS平台,运用单因子评价法和综合敏感性评价法构成城市生态适宜性评价的方法体系,以水域因子、坡度因子、湿地因子、覆被因子、灾害风险因子组建资源环境约束指标体系,将合肥市域划分为极高敏感区、高敏感区、中敏感区、低敏感区、非敏感区5 种资源环境承载类型区;基于反规划理念,构建滨湖城市空间增长模型,并划定作为城市扩展生态底线的刚性和弹性空间增长边界。在此基础上,统筹考虑城市空间资源环境保障能力、人口与用地规模,结合城市总体规划方案,明确城市空间扩展方向,科学划定城市近期、中期和远期的增长边界。该方法在中国滨湖城市的空间增长规模与方向、湖泊生态系统安保与开发、城市用地调控与优化组合以及城市规划方案的合理性评价方面可提供科学决策依据。     

Constructing a Social Justice Tour: Pedagogy,Race, and Student Learning through Geography

This article describes a high-impact learning project that combines geography, history, and ethnic studies. It describes the construction of the course, student outcomes, and the final and publicly presented collaborative project: the Social Justice Tour of Corvallis. Based on work in a small largely white town, this project presents a reproducible model for student learning and actively engaging with questions of race and geography.