基于“3S”的豫北平原近25年来土地利用变化研究——以内黄县为例

运用3S技术,分析了河南省内黄县1979~2003年的土地利用数量变化特征,结果显示,该区的土地利用类型变化显著;内黄县近25年土地利用的变化趋势为:耕地、水域和未利用地面积持续减少;林地、园地和交通建设用地面积呈现不断增加的态势;这集中反映了人口增长和经济建设需求对土地利用变化的影响,应采取有效措施减缓或阻止这种趋势的进展。     

4D cadastres: First analysis of legal,organizational, and technical impact—With a case study on utility networks

The increasing complexity and flexibility of modern land use requires that cadastres need an improved capacity to manage the third dimension. As the world is per definition not static, there also will be needs in relation to the representation of the temporal (fourth) dimension either integrated with the spatial dimensions or as separate attribute(s). In this paper, registration of utility networks in cadastre are considered in this 3D + time (=4D) context. A number of countries in the world have developed methods to register utility networks complying with their legal, organizational, and technical structure. We researched the different approaches of three specific countries: Turkey, The Netherlands and Queensland, Australia. These are analysed to evaluate a solution that matches legal, organizational, and technical cadastral requirements in the most optimal way.     

Is Scale and Cost Inefficiency in the Swiss Bus Industry a Regulatory Problem? Evidence from a Frontier Cost Approach

The aim of this study is to analyze the scale and cost inefficiencies in operation for the Swiss regional bus companies. For this purpose,we have considered estimation of a stochastic and a deterministic frontier cost model for a sample of 93 bus companies in 1989. The estimates of inefficiency from the frontier models are compared and discussed within the political and regulatory setting within which the Swiss regional bus companies operate. The empirical results indicate that regulation does not seem to influence the cost efficiency significantly. Only the tariff subsidies have a negative influence on efficiency. This is an interesting result because in the current transport policy debate, the abolition of this kind of subsidy has been raised.     

县级农业自然资源动态监测数据库设计

农业自然资源在国民生产,生活中占有重要地位,县级作为资源管理的基层行政单元十分有必要建立农业自然资源动态监测数据库,结合3S技术,对数据库的数据源作了分析和分类,并设计了数据库的结构和功能,提出了利用Arcview为平台开发设计县级农业自然资源动态监测数据库的方案。     

景观生态风险信息系统的概念、方法和步骤

景观生态风险信息系统（LERIS）是将景观生态学理论和3S技术相结合进行风险分析的现代规划管理系统。它通过对自然景观、人文因素矣风险源的全面调查，将所需的各类信息进行方便快速的采集、处理和管理等，利用GIS对景观生态状况和潜在风险进行分析、模拟和预测，从而为管理部门的决策提供科学的依据。LERIS在资源和环境的管理和规划领域具有广阔的应用前景。结合实例介绍了景观生态风险信息系统概念、方法和步骤，以期引起国内同仁的进一步关注。     

提高PH3防治效果的建议

针对当前PH3熏蒸存在的问题和新技术，提出6点建议。     

高大平房仓PH3环流熏蒸与常规熏蒸比较

通过对气密性良好的高大平房仓环流熏蒸和常规熏蒸过程中PH3浓度的检测，发现常规熏蒸PH3气体亦能穿透6m高的粮层，并且粮堆内各层点的浓度基本均匀，与空间浓度差别不大，有效浓度保持时间也较长，同时其工作时间和工作量均比环流熏蒸缩短和减少。为气密性良好的平房仓进行常规熏蒸提供了实践和理论依据。     

Temporal and spatial modelling of tropical deforestation: a survival analysis linking satellite and household survey data

We estimate a spatially explicit model of the forest clearance process among smallholder farmers in an agricultural frontier of southern Mexico. Our analysis takes as its point of departure a simple utility‐maximising model that suggests many possible determinants of deforestation in an economic environment characterised by missing or thin markets. Hypotheses from the model are tested on a data set that combines a time series of satellite imagery with data collected from a survey of farm households whose agricultural plots were geo‐referenced using a global positioning system (GPS). We implement a survival analysis to identify the effect of household level explanatory variables on the probability of deforestation. This approach allows us to introduce a measure of the time until clearance as a covariate, thereby affording a control for the effect of potentially important explanatory variables that vary through time but are not directly observable. In addition to identifying several variables relevant for policy analysis, including household demographics, proximity to roads, and government provision of agricultural support, model results suggest that the deforestation process is characterised by non‐linear duration dependence, with the probability of forest clearance first decreasing and then increasing with the passage of time.     

Capturing household-level spatial influence in agricultural management using random effects regression

Data on agricultural and natural resource management typically have spatial patterns related to the landscapes from which they came. Consequently, econometric models designed to explain the determinants of humans' natural resource management practices or their outcomes often have spatial structure that can bring bias or inefficiency to parameter estimates. Although econometric tools are available to correct for spatial structure, such tools are largely lacking for use with discrete dependent variable models. While one obvious solution would be to develop the necessary tools, an alternative is to identify conditions under which spatial dependency can be managed effectively without formal spatial autoregressive models. This study examines conditions under which spatial structure corresponds closely to defined agro‐ecological zones, making it possible to model spatial effects by random effects regression. Using household survey data sampled along agro‐ecological zone strata, this article develops two models of links between farmer assets and agricultural natural resource degradation in southern Peru. The first stage model looks at determinants of crop yield loss over time (an index of soil productivity), while the second stage model looks at determinants of the extent of fallow cycles in crop rotation, a key agricultural practice reducing crop yield loss. Diagnostic statistics for spatial dependency reveal spatial structure, particularly in the fallow model. This spatial dependency is eliminated in the ordinary least squares (OLS) models by inclusion of the agro‐ecological zone random effects. In the spatially dependent fallow model, comparison of coefficient estimates between OLS and the spatial autoregressive maximum likelihood models showed OLS with random effects to give virtually identical results to the spatial autoregressive models, making the latter unnecessary. These results show that spatial structure in natural resource management models can sometimes be captured by zonal variables. When this occurs, random effects regression can largely eliminate spatial dependency. A necessary precondition for this approach with household survey data is prior sample stratification according to landscape characteristics. Where random effects models can effectively capture spatial structure, they may also offer analysts greater flexibility in analyzing models with limited dependent variables.     

技术创新对中国外贸发展方式转变影响的实证研究

在分析1990年以来中国外贸发展方式转变状况的基础上,用协整检验和脉冲响应函数实证分析技术创新对外贸发展方式转变的影响。结果表明:技术创新是影响中国外贸发展方式转变的最主要因素,技术创新变量每增加1个百分点,外贸发展方式转变水平最大将提高1.91个单位;R&D投入强度对外贸发展方式转变过程中出现的波动性解释程度最大,达到56.33%,远大于其它因素的解释程度。因此,转变中国外贸发展方式,必须加快技术创新步伐,尤其要加大R&D投入。