可达性因子影响下城市土地利用动态模拟——以瑞典Jnkping市为例

城市交通布局对城市形态具有重大影响,也对城市的发展方向起着重大的引导作用。以瑞典J nk ping市为例,采用CLUE-S模型模拟不同交通情景下的城市发展动态变化。首先,基于2000年土地利用数据,选择影响土地利用变化的驱动因子构建Logistic回归方程。然后利用CLUE-S模型,在模型检验和参数验证的基础上,模拟未来25年不同交通情景下城市形态空间格局的变化。结果表明:可达性因子的选择对于改善用地类型的回归结果具有显著影响;不同的道路类型和交通设施等级对各用地类型转换概率有不同程度的影响。对两种不同的交通规划情景下的土地利用空间分布格局的动态模拟发现,在未来交通规划情景下,土地利用动态度增加,且在城市中心区交通发达的区域,城市呈现填空式拓展,新增加的城市用地分布比较集中;城市外围表现出较强的沿交通线的拓展趋势,城市空间结构与城市交通互动关系明显。     

镇江市土地利用格局演变与情景模拟

以镇江市为例,运用动态度模型、转移矩阵分析1994—2012年土地利用格局的演变特征,并设定情景方案利用改进的CLUE-S模型对区域未来演变趋势进行模拟预测。结果表明:1994年以来镇江市土地利用呈现出"缓慢提升—快速上升—稳步下降"动态演变特征;土地利用类型转移主要表现为耕地向建设用地、林地和其他农用地向园地景观类型的转化;改进的CLUE-S模型在300m×300m尺度上最佳,耕地保护情景下,限制区内基本农田用途转化,制约了建设用地的适度扩张,预计到2030年耕地比重增加4.35%,主要分布在镇东平原区;经济发展情景下,建设用地空间扩张最为显著,预计到2030年面积增加15.26%,主要侵占各建成区周边大量耕地;生态保护情景下,预计到2030年林地、水域等生态保护用地面积增加,主要分布在镇西丘陵区。分情景的模拟方案为区域土地利用调整与优化提供科学依据。     

黑龙江省县域土地利用格局优化研究

土地利用格局优化对改善区域生态环境和实现土地可持续利用具有重要意义。文章以黑龙江省产粮大县——巴彦县为研究区,运用3S技术,采用Matlab编程,建立土地利用格局元胞自动机优化模型,对2020年研究区土地利用格局进行优化。结果表明:1经本文改进的元胞自动机模型具有较好的土地利用格局优化能力。2土地利用格局优化后,研究区耕地和草地面积减少,林地和建设用地面积增加;从格局变化的环境效应角度出发,耕地面积应控制性的减少,其他用地类型面积适当增加,特别是林地面积亟待大幅提升。3经优化,研究区林地和草地较为集中,建设用地空间分布较为分散,耕地的空间分布大致和现状保持一致;土地利用格局变化的敏感地区主要位于西北部地区和东北部地区;林地、草地、建设用地的变化均直接与耕地的变化相关,土地利用格局的变化具有显著的区域分异特征。     

经济与生态效益不同情景下的广州市土地利用优化配置

缓解生态保护与经济发展之间的矛盾已成为广州市目前亟须解决的重要现实问题。通过对经济效益和生态效益最大化的不同侧重,基于多目标规划模型与CLUE-S模型对广州市2025年不同情景下的土地利用进行优化配置。结果表明:(1)与现状相比,兼顾两者效益情景的土地利用优化方案最为合理:效益提升最为协调分别为9.35%、9.58%,不同景观类型破碎化程度适中;(2)广州市对生态、经济效益的不同侧重主要导致林地、建设用地和水域面积的变化较大,未来规划应注重这三种地类的合理规划;(3)多目标规划与CLUE-S模型的结合,可以有效解决广州市多情景的土地资源优化配置模拟。研究结果对广州市土地利用可持续发展和生态文明建设具有较大的参考价值。     

北京都市区居住与产业用地空间格局演化及其对居民通勤行为的影响

以北京都市区为研究案例地,采用核密度估计法、Ripley’s K(d)函数分析了北京都市区土地利用空间格局的分布特征与集聚强度,在此基础上,运用多层模型,重点分析了不同土地利用类型对居民通勤行为的影响。研究结果表明:①不同时间段内产业用地的集聚强度都要高于居住用地的集聚强度,说明居住用地出让的空间分布格局更为分散化,而产业用地出让的空间分布格局更为集聚。②土地利用格局显著影响居民的通勤行为,随着产业用地与居住用地密度的提升,居民的通勤时间与通勤距离都明显缩短,说明居住在土地混合程度越高区域的居民能够充分利用区位优势来优化通勤行为;个体属性特征如性别、年龄、职业、住房产权以及邻里特征等因素也会显著影响居民的通勤时间与通勤距离。     

可达性因子影响下城市土地利用动态模拟——以瑞典J6nkoping市为例

城市交通布局对城市形态具有重大影响,也对城市的发展方向起着重大的引导作用。以瑞典Jonkoping市为例,采用CLUE—S模型模拟不同交通情景下的城市发展动态变化。首先,基于2000年土地利用数据,选择影响土地利用变化的驱动因子构建Logistic回归方程。然后利用CLUE—S模型,在模型检验和参数验证的基础上,模拟未来25年不同交通情景下城市形态空间格局的变化。结果表明：可达性因子的选择对于改善用地类型的回归结果具有显著影响;不同的道路类型和交通设施等级对各用地类型转换概率有不同程度的影响。对两种不同的交通规划情景下的土地利用空间分布格局的动态模拟发现,在未来交通规划情景下,土地利用动态度增加,且在城市中心区交通发达的区域,城市呈现填空式拓展,新增加的城市用地分布比较集中;城市外围表现出较强的沿交通线的拓展趋势,城市空间结构与城市交通互动关系明显。     

京津冀都市圈“三生”空间时空格局演变及其驱动力研究

基于“格局—过程—影响—可持续性”的研究思路,探究了2000—2018年京津冀都市圈内“三生”空间变化及其驱动力。研究表明:都市圈内“三生”空间变化显著,各用地类型间发生了复杂的土地利用转移,其复杂性体现在不同时期内地类主要的转化方向和速度不同,以及同一时期不同地点的转化方向不同;都市圈内生产空间减少,生态空间和生活空间增加,生产空间大量转为生活空间是土地利用转移的主要趋势;京津冀都市圈“三生”空间分布呈“双轴一主一副”格局且较为稳定;通过主成分分析法得出,人口增加和经济发展、农业技术进步和农业效益低下是推动“三生”空间变化的主要驱动力。制约“三生”空间可持续利用的主要问题分别为耕地严重流失和农村生活用地比重过大,应通过基本农田保护、农业技术革新以及土地整治等政策规划和技术的提升优化“三生”空间利用与布局。     

土地利用效率的空间格局与溢出效应

采用全局空间自相关模型、Getis-Ord Gi*模型对中国31个省域的建设用地利用效率、农用地利用效率、土地利用综合效率进行分析。结果显示,三者均呈现空间集聚特征,建设用地热点区域面积小于农用地热点区域,建设用地热点区域与冷点区域面积仅占全部研究区面积的1/4,研究区半数省域属于土地利用效率无显著差异型。     

基于地形梯度的土地利用格局与时空变化分析——以北京市平谷区为例

地形在一定程度上影响着土地利用变化,对土地利用空间格局的形成具有重要影响.以北京市平谷区为例,借助DEM提取高程、坡度信息,采用地形位指数、分布指数、土地利用程度综合指数系统分析平谷区1993-2008年土地利用变化的地形梯度特征,探讨地形因素对土地利用方式选择及空间格局的影响,以期为该区土地利用规划及土地资源优化布局提供决策依据.结果表明:①1993-2008年,平谷区耕地面积大幅度减少,园地、居民点及工矿用地、交通用地大幅度增加;②坡度、高程及地形位对平谷区土地利用格局及其时空变化有着重要影响.③耕地、园地、居民点及工矿用地、交通用地、水域分布的优势区间集中于低地形位区间,草地分布的优势区间集中于中地形位区间,林地、未利用地分布的优势区间集中于中高地形位区间,土地利用程度综合指数随着地形位的增加而不断下降.     

黑龙江省巴彦县土地利用类型变化特征及其空间格局分异

以黑龙江省巴彦县为研究区,以1976—2011年间12期遥感影像为数据源像,运用景观生态学理论,在RS、GIS技术支持下,对研究区1976—2011年各种用地类型的数量变化、结构变化、组合方式变化特征及空间格局特征进行研究,以揭示研究区土地利用变化规律。结果表明:1研究区土地利用类型组合方式以旱地和林地为主,其中旱地面积最大,占总面积的50%以上。1976—2011年,土地利用类型变化特征主要表现为建设用地和其他用地面积减少,从而导致旱地面积大幅度增加;林地面积明显增多,主要由旱地转入;牧草地面积减少,其转出主要为旱地、建设用地和其他用地;建设用地、其他用地、水域和园地面积逐渐减少,水田面积增多。21976—2011年,研究区景观分离度、景观多样性和景观形状均呈下降趋势,1976—1988年、1988—2000年、2000—2011年3个时间段内,研究区土地利用格局分布的集散程度呈现出"集中—分散—集中"的变化特征;格局整体稳定性呈"稳定—不稳定—稳定"的复合稳定性特征;格局形状呈"简化—复杂—简化"的变化特征。31976—2011年,研究区土地利用类型变化在空间上呈现出明显的分异特征,土地利用类型变化最频繁的区域主要集中在研究区南部的富江乡和松花江乡,东部的洼兴镇与西部的西集镇和红光乡。     

Forecasting the price of gold

This article seeks to evaluate the appropriateness of a variety of existing forecasting techniques (17 methods) at providing accurate and statistically significant forecasts for gold price. We report the results from the nine most competitive techniques. Special consideration is given to the ability of these techniques to provide forecasts which outperforms the random walk (RW) as we noticed that certain multivariate models (which included prices of silver, platinum, palladium and rhodium, besides gold) were also unable to outperform the RW in this case. Interestingly, the results show that none of the forecasting techniques are able to outperform the RW at horizons of 1 and 9 steps ahead, and on average, the exponential smoothing model is seen providing the best forecasts in terms of the lowest root mean squared error over the 24-month forecasting horizons. Moreover, we find that the univariate models used in this article are able to outperform the Bayesian autoregression and Bayesian vector autoregressive models, with exponential smoothing reporting statistically significant results in comparison with the former models, and classical autoregressive and the vector autoregressive models in most cases.     

Planned adaptation in risk regulation: An initial survey of US environmental, health, and safety regulation

In principle, we want regulatory programs to be based on current realities, as reflected for example in the best knowledge of relevant experts. That would imply that old rules now on the books should be consistent with today's knowledge base, not just what was known when a rule or standard was originally set. This paper reports on a survey of US programs, examining how often existing rules are actually updated in light of better knowledge, and identifies five programs that attempt to make policy routinely adaptive. These programs exhibit what we term Planned Adaptation: they both revise rules when relevant new knowledge appears, and take steps to produce such improved knowledge. While Planned Adaptation is rare, it is used in several nationally prominent programs, including air pollution, airplane safety, and drug safety. Planned Adaptation is a policy tool that deserves more attention.     

Pleasure and belief in Hume's Decision Process

Abstract

The purpose of this paper is to introduce explicitly pleasure and belief in what aims at being a Humean theory of decision, like the one developed in Diaye and Lapidus (2005a). Although we support the idea that Hume was in some way a hedonist – evidently different from Bentham's or Jevons' way – we lay emphasis less on continuity than on the specific kind of hedonism encountered in Hume's writings (chiefly the Treatise, the second Enquiry, the Dissertation, or some of his Essays). Such hedonism clearly contrasts to its standard modern inheritance, expressed by the relation between preferences and utility.

The reason for such a difference with the usual approach lies in the mental process that Hume puts to the fore in order to explain the way pleasure determines desires and volition. Whereas pleasure is primarily, in Hume's words, an impression of sensation, it takes place in the birth of passions as reflecting an idea of pleasure, whose “force and vivacity” is precisely a “belief”, transferred to the direct passions of desire or volition that come immediately before action. As a result, from a Humean point of view, “belief” deals with decision under risk or uncertainty, as well as with intertemporal decision and indiscrimination problems.

The latter are explored within a formal framework, and it is shown that the relation of pleasure is transformed by belief into a non-empty class of relations of desire, among which at least one is a preorder.     

The greenhouse effect: Damages,costs and abatement

The buildup of so-called greenhouse gases in the atmosphere — CO₂ in particular-appears to be having an adverse impact on the global climate. This paper briefly reviews current expectations with regard to physical and biological effects, their potential costs to society, and likely costs of abatement. For a worst case scenario it is impossible to assess, in economic terms, the full range of possible non-linear synergistic effects. In the most favorable (although not necessarily likely) case (of slow-paced climate change), however, it seems likely that the impacts are within the affordable range, at least in the industrialized countries of the world. In the third world the notion of affordability is of doubtful relevance, making the problem of quantitative evaluation almost impossible. We tentatively assess the lower limit of quantifiable climate-induced damages at $30 to $35 per ton of CO₂ equivalent, worldwide, with the major damages being concentrated in regions most adversely affected by sea-level rise. The non-quantifiable environmental damages are also significant and should by no means be disregarded.The costs and benefits of (1) reducing CFC use and (2) reducing fossil fuel consumption, as a means of abatement, are considered in some detail. This strategy has remarkably high indirect benefits in terms of reduced air pollution damage and even direct cost savings to consumers. The indirect benefits of reduced air pollution and its associated health and environmental effects from fossil-fuel combustion in the industrialized countries range from $20 to $60 per ton of CO₂ eliminated. In addition, there is good evidence that modest (e.g. 25%) reductions in CO₂ emissions may be achievable by the U.S. (and, by implication, for other countries) by a combination of increased energy efficiency and restructuring that would permit simultaneous direct economic benefits (savings) to energy consumers of the order of $50 per ton of CO₂ saved. A higher level of overall emissions reduction — possibly approaching 50% — could probably be achieved, at little or not net cost, by taking advantage of these savings.We suggest the use of taxes on fossil fuel extraction (or a carbon tax) as a reasonable way of inducing the structural changes that would be required to achieve significant reduction in energy use and CO₂ emissions. To minimize the economic burden (and create a political constituency in support of the approach) we suggest the substitution of resource-based taxes in general for other types of taxes (on labor, income, real estate, or trade) that are now the main sources of government revenue. While it is conceded that it would be difficult to calculate the optimal tax on extractive resources, we do not think this is a necessary prerequisite to policy-making. In fact, we note that the existing tax system has never been optimized according to theoretical principles, and is far from optimal by any reasonable criteria.During the academic year 1989–90 Dr. Ayres was at the International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.During the summer of 1989 Mr. Walter was a member of the Young Scientists' Summer Program at IIASA.     

Globalization,Neoliberalism and the attack on social security

Neoliberal political movements advocate privatization of public pension systems. Globalization imposes pressure on nations to conform to neoliberal policy views with respect to the design and structure of social insurance, including public pension systems. The paper begins with an investigation of the economic, ethical and ideological dimensions of the privatization debates in the U.S.; it argues that privatization advocates may be largely moved by ideology, since the other reasons advanced appear weak or unfounded. The second part discusses the history of Social Security, the purposes for its creation, and some of its economic effects. Differences between public and private pension systems are considered. A brief international comparison of some aspects of public pension system finance and benefit structures is presented. The final section considers the ethical, macroeconomic and distributional implications of privatization, prefunding and payroll tax funding, and argues for a pay as you go system financed with income taxes. In order to promote equity, economic security, community, and social cohesion, public pension systems should be universal in coverage. In order to reduce the inequality, income insecurity, and aged poverty generated by market economies, public pension systems ought to be progressive: benefit/contribution ratios should be inversely proportional to income, and progressive income taxes should finance the system. To promote economic growth, the systems should be financed on a pay-as-you-go basis, and should not be prefunded except for an emergency reserve. The fiscal policy recommendations partially depend upon the theory developed by Abba Lerner in the 1940s, and recently advanced by Wynne Godley and Randy Wray: Lerner's “principle of functional finance.”     

SCIENCE AND INDUSTRY: TRACING THE FLOW OF BASIC RESEARCH THROUGH MANUFACTURING AND TRADE

This paper describes flows of basic research through the US economy during the late 20th century. In addition, the paper studies the effect of the flows on scientific papers in industries and fields. This article differs from others in its use of measures of science rather than technology. Together, its results present a picture of the structure of basic research flows in a modern, science-intensive economy. Basic research flows are large within petrochemicals and drugs, and within software and communications. Flows of chemistry, physics, and engineering are common throughout all industries – biology and medicine are almost confined to petrochemicals and drugs; and computer science is nearly as restricted to software and communications. In general, basic research flows are more concentrated within scientific fields than within industries. Our findings concerning the production of scientific papers indicate that the effect of a 1% change in academic R&D spillovers significantly exceeds that of industrial spillovers. In addition, within-field effects exceed effects between-fields, while within- and between-industry effects are roughly equal. It follows that scientific fields limit basic research flows more than industries do, perhaps because large firms implicitly span a range of industries.     

Valuing Mangrove-Fishery Linkages – A Case Study of Campeche, Mexico

This paper explores the value of mangrove systems as a breeding and nursery habitat for off-shore fisheries, focusing on mangrove-shrimp production linkages in Campeche State, Mexico. We develop an open access fishery model to account explicitly for the effect of mangrove area on carrying capacity and thus production. From the long-run equilibrium conditions of the model we are able to establish the key parameters determining the comparative static effects of a change in mangrove area on this equilibrium. We then estimate empirically the effects of changes in mangrove area in the Laguna de Terminos on the production and value of shrimp harvests in Campeche over 1980–90. Our findings suggest that mangroves are an important and essential input into the Campeche shrimp fishery, but that the low levels of deforestation between 1980 and 1990 mean that the resulting losses to the shrimp fishery are still comparatively small. Over-exploitation of the fishery due to open access conditions remains the more pervasive threat, and without better management any long-run benefits of protecting mangrove habitat are likely to be dissipated.     

Interest on reserves and inflation

The payment of interest on reserves has been a common practice in inflationary economies. This policy may seem paradoxical since it involves returning part of the seigniorage, generated by the inflation process, with the intention to finance the fiscal deficit. This paper argues that the motivation for this policy can be captured by the discretionary regime, where the policymaker pays interest on reserves because he is concerned with the erosion of real liquidity by inflation, which is in part beyond his control. However, this policy is an unlikely outcome in the commitment regime, where the policymaker is in full control of inflation.     

An Economic Analysis and Simulation of Woodfuel Management in the Sahel

This paper presents an economic framework and a computationalmethodology for assessing the evolution of woodfuel supply costsand the spatial distribution of biomass in a Sahelian woodlandsetting. Spatial data on standing stock and the costs oftransport to market are used to construct a supply curve for fuelto a fuel-consuming location. Given an exogenously specifieddemand, the model simulates, period by period, the extraction,regeneration, and transport of wood fuels. The model is appliedto evaluate the benefits and ecological impacts of scenarios forwoodland management around the city of N'Djamena, Chad.