水生态系统服务供需视角下的水网乡村 适应性规划策略——以吴江张鸭荡片区为例

苏南乡村地区一直是中国乡村建设的先行区域，特殊的纵横交错的水网结构构成了一个错综复杂的系统，呈现出其他地区不具有的复杂性和生态特殊性。随着城镇的扩张，乡村的发展建设使其水网空间的平衡发展面临极大的挑战。传统单一静态的规划方法逐渐显示出无法适应经济、社会等发展要求的缺陷。苏南乡村地区以水为核心，从水生态系统服务供需关系的视角下探究水网乡村的适应性规划策略更加适应当前的乡村现状和需求。以传统水网乡村空间形态转译为基础，建立水生态系统供需服务评估体系，在评估水生态系统服务供需能力的基础上，分析供需分异模式及供需矛盾。从构建乡村水域空间生态格局、乡村水域空间功能分区规划，以及乡村水域空间多情景预判3个方面，提出苏南水网乡村的适应性规划策略，并为水网乡村的生态实践提出新思路。     

基于ANP的社区低碳系统结构分析

21世纪初以来,世界范围内出现了一系列社区低碳可持续评估工具(NSA tools),NSA tools的优化已成为国内外学者研究热点,然而研究发现既有评价系统大多基于指标间相互独立的假设,而对指标间的相互影响考虑较少。为解决这一问题,基于对社区低碳关键领域的分析构建了社区低碳系统,遵循"控碳源,扩碳汇"的基本理念将该系统划分为两个维度:"碳源控制"系统(简称C系统)和"碳汇扩展"系统(简称E系统),通过对系统内部关联性的分析,构建ANP网络结构模型以优化现有权重体系,为NSA tools的优化研究提供了新的思路。     

房地产市场GERT网络模型应用研究——基于极大熵参数配置

采用极大熵方法配置参数,构建了考虑体外循环的GERT网络模型,研究投资决策参量的相关参数的函数关系、运算法则及确定方法,提出了考虑体外循环的GERT网络模型求解算法。将该GERT网络模型应用于房地产市场领域,研究房地产市场中各参与主体之间的投资决策流动系统。结果显示,利用该GERT网络模型能充分反映房地产市场中各部门之间、房地产市场部门与体外环境部门之间的交互影响关系,可得到科学合理的量化结论。     

物元分析法在科技计划项目绩效评估中的应用

根据目前科技计划项目绩效评估的现状,依据科技计划项目绩效评估体系的构建理论和方法,对科技计划项目绩效评估的业务流程进行了系统的研究,提出了基于物元分析法的科技计划项目绩效评估模型。首先介绍了物元数学模型的建立原理,然后依据物元分析法的原理构建了科技计划项目绩效评估的模型,最后从某市的已评估的科技计划项目中挑选了3个具有代表性的项目作为案例,对该模型进行了验证,结果显示与实际结果相符。     

基于Rhino+Grasshopper的风景环境 复杂地形道路选线设计算法模型研究

在风景园林规划设计中，当前使用ArcGIS作为道路自动选线工具的研究较多，但该方法在小区域内无法取得较为精准的选线结果。基于Rhino+Grasshopper平台，对Dijkstra最短路径算法、遗传算法及道路选线影响因素进行研究，构建了参数化风景环境道路自动选线模型。使用参数化设计生成的路径符合风景区低影响开发和低成本建设的原则，且路径曲线最大限度满足风景区道路极限平曲线现行规范值。构建的参数化模型可以解决所有同类型问题且便于调整和优化，为风景环境道路选线提供了新的解决方法。     

KMV模型在我国的实务化

本文规划了一个KMV模型实务化的框架.即结合传统信用度量方法,按不同行业建立相应的在参数设置上有差异的,比较符合该行业经济特征的行业KMV模型,以期通过KMV模型实务化来应用学术界的研究成果,并尝试运用KMV模型在我国建立一套有效的、可操作的、较完整的信用评价系统.     

基于BP神经网络模型的海绵城市建设适宜性评价——以福建省长汀县为例

当前我国海绵城市建设适宜性评价研究多集中在"工程"技术层面,缺乏社会经济和生态环境综合视角的评价研究。基于此,文章以福建省长汀县为实证对象,构建了一种基于生态、社会、经济多维指标的系统建模评价方法。首先,从孕灾环境危险程度、承灾体易损程度、海绵体改造适应能力三个维度构建海绵城市建设适宜性评价指标体系;进而,对城市空间采用元胞栅格化、指标分级量化、人口密度估算等方法计算和生成各个指标的量化分级图层;最后,基于熵值法确定的指标权重,构建拓扑结构为9×3×1的BP神经网络模型对海绵城市建设的适宜性进行评价。评价结果表明,该方法可为海绵城市专项规划中,海绵体的城市空间布局及其建设时序规划提供科学指导。     

同步优化思想在个人信用评估中的运用

在对目前个人信用评估方法分析的基础上,提出了对于信用评估的重要指标提取和模型参数选择这两个过程进行同步优化的方法,利用评估指标和评估模型参数的互相依赖关系来提高整个信用评估系统的分辨能力,并以支持向量机(SVM)为模型进行了实证检验。结果表明,同步优化方法能更好地提高模型整体的性能,分类正确率有明显的提高。     

系统动力演进视角下湛江海洋经济系统及运行机制研究

随着海洋强国战略的提出,海洋经济及海洋产业发展逐渐成为人们关注的焦点.研究沿海城市海洋经济系统构成,分析其关键要素,对于促进区域海洋经济发展具有重要意义.本文以系统动力演进思想为指导,采用模型化方法及分析手段,从中微观层面构建湛江市海洋经济创新发展的运行机制,探讨湛江市海洋经济创新发展的战略选择.     

厦—泉—漳城市群重大工程建设对区域地质环境影响评估的对策研究

以海峡西岸经济区城市群协调发展为背景,以厦—泉—漳城市群建设为例,介绍了城市群建设发展、正在施工项目和规划建设的重大工程等整体概况;从福建东南沿海区域地质环境、评估指标体系与评估模型、影响评估方法及计算机评估软件、地质环境修复等四个不同方面,系统提出重大工程建设对地质环境影响研究对策、研究方法和技术手段。研究对厦—泉—漳城市群和其他沿海城市群的规划发展和建设具有参考价值,对维护区域地质环境系统平衡、实现海峡西岸经济区城市群可持续发展、协调重大工程建设与地质环境保护关系等具有重要的理论和现实意义。     

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.     

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.     

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.     

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.     

新员工主动社会化行为与组织承诺关系研究——以社会资本为中介变量

为了探索新员工主动社会化行为影响组织承诺的过程,本文对来自企业的401个有效样本进行了实证分析。本研究运用层级回归的方法,控制了人口统计变量的影响后,发现员工的搜寻信息和搜寻绩效反馈行为对组织承诺有直接的正面影响,同时,通过员工社会资本对员工组织承诺产生了间接的正面影响。社会资本在员工搜寻信息和搜寻绩效反馈行为影响组织承诺的机制中起部分中介作用。员工的关系构建行为对组织承诺没有显著影响,但对员工社会资本存在显著的正面影响。     

Zvi Griliches's contributions to the economics of technology and growth*

Zvi Griliches's contributions to the economics of technology and growth are identified. Included is a discussion of his contributions on: the determinants of differences in speed of adoption of innovations; the use of patents to measure technology; the private and social returns to R&D; and spillover effects from R&D. Griliches's own evaluation of his research contribution is compared to the evaluation of others in the field, using as evidence citation counts of his works collected from the online Web of Science. Griliches's most important contribution is his 1957 Econometrica hybrid corn paper that is a foundation of the economics of technological innovation. Remarkably, the trend in annual citations to the paper has continued to increase for over 40 years. Finally, we summarize Griliches's most recent views on the practice of economics and on the most important unanswered questions in the economics of technology and growth.     

Evidence on the impact of R&D and ICT investments on innovation and productivity in Italian firms

Both research and development (R&D) and information and communication technology (ICT) investment have been identified as sources of relative innovation underperformance in Europe vis-à-vis the USA. In this article, we investigate the R&D and ICT investment at the firm level in an effort to assess their relative importance and to what extent they are complements or substitutes. We use data on a large unbalanced panel data sample of Italian manufacturing firms constructed from four consecutive waves of a survey of manufacturing firms, to estimate a version of the CDM model of R&D, innovation, and productivity [Crépon–Duguet–Mairesse 1998. Research, innovation and productivity: An econometric analysis at the firm level. Economics of Innovation and New Technology 7, no. 2: 115–58] that has been modified to include ICT investment and R&D as the two main inputs into innovation and productivity. We find that R&D and ICT are both strongly associated with innovation and productivity, with R&D being more important for innovation, and ICT investment being more important for productivity. For the median firm, rates of return to both investments are so high that they suggest considerably underinvestment in both these activities. We explore the possible complementarity between R&D and ICT in innovation and production, but find none, although we do find complementarity between R&D and worker skill in innovation.