An extortionary guerrilla movement

This paper models an extortionary relationship between a pipeline operator and a guerrilla movement. Payment and attack decisions are modeled as an infinite-horizon Markov decision process, where each period the oil company chooses to pay or not pay an extortion demand and the movement decides to attack or not. Decisions depend on the level of single-period payoff and discounted expected future payoffs. We estimate the model with pipeline attack data and compare parameters when the discount factor is changed. We reject a zero discount factor hypothesis, demonstrating that the movement's observed attack pattern is compatible with extortionary behavior. Copyright © 2007 John Wiley & Sons, Ltd.     

On the use of Markovian equilibrium distributions for land use policy evaluation

Using the Markov model of land use change as a framework for analyzing the impact of alternative land use policies, comparison of Markovian equilibrium distributions resulting from constrained simulations has been promoted as a means of evaluating the scope of land use policy impacts. Previous studies have not considered the question of measuring the confidence which can be placed in the predictions contained in the equilibrium distribution vector. This paper applies a method of assessing the levels of confidence in the predictions of the equilibrium distribution vector. Results suggest that use of equilibrium distributions of land use as a measure of policy impact has limited inferential value.     

The determination of stability and similarity of Markovian land use change processes: A theoretical and empirical analysis

This paper examines the process of land use change as a Markov process. The model as developed in this paper ateempts to specify criteria to determine the stability and similarity of the process of land use change before it reaches the equilibrium state which may take an infinite number of time periods. It is shown that the model is capable of identifying the time horizon during which the system shows sufficient stability since prediction with respect to future pattern is more likely to conform to the actual pattern if the system in question is stable.     

基于城镇空间区域扩展分析的城市化进程评估

城市扩展的空间数据是评估城市化进程的一个重要指标。文章以福清市为例 ,探讨了利用城市发展的空间数据研究城市化进程的原理和方法。文章综合应用遥感和地理信息系统技术分别提取了福清市 1991年和 1996年的城镇用地信息 ,发现在这 5年中 ,福清市城镇用地面积增加了 1 2倍。经过对城镇区域扩展进行空间分析 ,并结合社会经济统计数据进行逐步回归和主成分分析 ,进一步查明了福清市城镇化进程的驱动力主要为工业大发展和非农业人口的增加。但是 ,房地产业的兴起和交通运输业的发展也在某些乡镇和地区起了重要的作用。综合多因子分析表明 ,福清市城市化水平的提高主要得益于乡村的城镇化 ,而不是中心城区的贡献。总的看来 ,福清市城市化的水平明显落后于经济发展和城镇空间扩展的速度 ,大力发展第三产业是提高福清市城市化水平的主要途径。     

Conceptual structures as damped harmonic oscillators

This paper serves to examine certain hypotheses about the effect of information on cognitive processing generated by the Galileo model. This model proposes that objects of cognition are points within a multidimensional continuum, the definition of any object being its structural relation to all other objects in the continuum, and any change in structure can be modeled by Newtonian mechanics. This paper tests the hypothesis that new information will induce motion described by the equation for a damped harmonic oscillator, and that regions of the continuum where information is not directed will display motion as described by DeBroglie's equation. Results tentatively support the hypotheses, and the relation of this conceptualization with compatible models of physical reality is discussed.     

重庆市土地利用变化及其驱动力分析

以重庆市土地利用变更数据、统计年鉴及相关资料为基础,把定性和定量分析结合起来,通过对重庆市土地利用动态、土地利用程度变化等情况进行分析,得出结论:经济增长、人口变化、产业结构变动、城镇化、国家和地方政策是重庆市土地利用变化的驱动力。     

GIS支持下的土地利用/覆被变化与生态效应测评研究

利用西安市1988、2000年两期遥感影像,根据地学信息图谱理论与地球空间信息认知理论,以ARCGIS9.0和ERDAS8.5为平台分析了西安市1988-2000年间土地利用时空演变过程;并对研究区1988-2000年土地利用变化引起的生态效应变化进行了测算;结果表明:12年间西安城区土地利用,覆被变化剧烈,综合土地动态度为3.5%,建设用地面积则急剧增加,年变化率达到为261.1%;西安城区生态系统服务价值在12年间从306.7 × 106元减少到259.8×106元,共减少了46.9×106元;本文证明用3S手段研究由于土地利用/覆被变化引起的生态响应是一种行之有效的方法.     

基于土地杠杆的住房价格动态分解

住房可分为土地和依附于土地的建筑物两部分。基于土地杠杆基本概念,利用我国35个大中型城市数据,将住房价格动态分解为土地价格和建筑物价格,考察我国住房价格增长中土地增值的贡献比例与速度。对土地杠杆假说的实证检验发现,拥有更高土地杠杆的住房,其增值速度会更快。通过对土地杠杆假说的实证研究,对于了解潜在的房价决定机制、价格指数建立、土地利用限制的成本评估,以及制定住房政策和评估住房市场的合理性等,都具有重要的作用。     

Testing the Markov property with high frequency data

This paper develops a framework to nonparametrically test whether discrete-valued irregularly spaced financial transactions data follow a Markov process. For that purpose, we consider a specific optional sampling in which a continuous-time Markov process is observed only when it crosses some discrete level. This framework is convenient for it accommodates the irregular spacing that characterizes transactions data. Under such an observation rule, the current price duration is independent of a previous price duration given the previous price realization. A simple nonparametric test then follows by examining whether this conditional independence property holds. Monte Carlo simulations suggest that the asymptotic test has huge size distortions, though a bootstrap-based variant entails reasonable size and power properties in finite samples. As for an empirical illustration, we investigate whether bid–ask spreads follow Markov processes using transactions data from the New York Stock Exchange. The motivation lies on the fact that asymmetric information models of market microstructures predict that the Markov property does not hold for the bid–ask spread. We robustly reject the Markov assumption for two out of the five stocks under scrutiny. Finally, it is reassuring that our results are consistent with two alternative measures of asymmetric information.     

Family planning availability and contraceptive use in rural Bangladesh: An examination of the distance decay effect

Using empirical data collected from a rural area of Bangladesh, this paper examines the effect of family planning availability on contraceptive use. The hypothesis is that the likelihood of contraceptive adoption is a function of accessibility to two different types of family planning service outlets (i.e. distance from these outlets has an impact on the use of contraception by married women of reproductive age, 15–49 yr). But the field data do not show a distance decay effect between availability and use of both clinical and non-clinical contraceptive methods. The observed effect is explained in terms of the presence of paved roads in the study area. The policy implications of this finding are discussed.     

An Empirical Model of Land Use Change in China

The aim of this paper is to develop an empirical model of land use change that integrates the growth of regional economy and land use change in a developing country such as China. The concept of ecological growth in terms of regional resources and population is introduced to make an empirical model of land use changes. It is shown that the model might be an efficient tool to analyze and predict regional land use change, and that the policies based on it can play an important role in land use change in China.     

Markov analysis of land use change: Continuous time and stationary processes

In an earlier paper one of the authors has used actual land use maps to establish the validity of the Markov process for describing and projecting land use changes. In a subsequent paper the same data was used to calibrate a non-homogeneous, birth and death process in which the land uses were dichotomized into either of two states: developed or undeveloped. The present paper pursues two aspects raised by the earlier ones: whether the process of land use changes can be considered a stationary process and, if so, whether it can be fit by a continuous-time, rather than discrete-time, model. Necessary and sufficient conditions for the existence of a feasible fit are indicated.     

Testing the unbiased forward exchange rate hypothesis using a Markov switching model and instrumental variables

This paper develops a model for the forward and spot exchange rate which allows for the presence of a Markov switching risk premium in the forward market and considers the issue of testing the unbiased forward exchange rate (UFER) hypothesis. Using US/UK data, it is shown that the UFER hypothesis cannot be rejected, provided that instrumental variables are used to account for within‐regime correlation between explanatory variables and disturbances in the Markov switching model on which the test is based. Copyright © 2005 John Wiley & Sons, Ltd.     

The position of agriculture in kibbutz economy—an attempt at quantitative projection

The Israeli Kibbutz Movement adopted the ideology of the “Return to Nature” and aspired to especially develop agricultural labour. But in the past decade there has been a process of “internal migration” of workers from agriculture to industrial occupations, which was compared to the “Industrial Revolution”. The ratio of agricultural workdays to other productive branches workdays decline from 62% in 1967 to 46.5% in 1974. Kibbutz' management has many reasons to evaluate its future direction, (investment in land, in education, etc.). We shall try to describe the expected developments, using the Markov chain. We shall also try to analyse the yearly interchanges and transfer from agriculture to industry and vice versa. We shall attempt to show that the process of decreasing agricultural manpower has almost ceased, and it will become stable on a fixed level of about 43%.     

浅谈RS与GIS在土地规划和利用中的应用

随着农业结构的调整、城市化进程的加快和第三产业的快速发展,传统农业用地的结构有了很大的变化。土地类型的转化和土地的各种数据的更新速度之快,技术要求之高,对土地利用现状动态监测的科技含量提出了更新更高的要求,遥感(RS)和地理信息系统(GIS)技术在土地规划和利用中也有了越来越广泛的用途。     

集成遥感与GIS技术的土地利用动态变化监测方法研究

尽管国内外已发表了许多利用两个或两个以上时相遥感影像进行土地利用动态变化监测的研究成果,但鲜有基于单时相遥感影像与土地利用现状图进行土地利用动态变化监测的研究成果出现。本文将以土地利用现状GIS数据和高分辨率遥感影像为数据源,探讨利用GIS数据和相应分辨率的单时相遥感影像进行土地利用动态变化监测的有关技术方法和技术流程,并通过实验验证方法和技术流程的有效性和可行性。     

政策影响下土地利用空间布局变化模拟分析

目前,对土地利用在空间布局方面的研究已经成为新兴热点,而对于政策影响下的土地利用空间布局变化模拟研究与分析的成果尚只存少数。因此,本文在对研究区进行土地利用现状于结构和空间布局两方面的分析的基础上,根据研究区当前面临的主要土地利用变化相关政策进行需求变化研究,通过合理选择土地利用分类,运用逻辑回归分析及ROC曲线等方法进行反复的驱动因子筛选,最终选出最适用于研究区特点的因子,并通过CLUE-S模型对土地利用变化政策在空间布局上的影响做出合理模拟。结果显示,采用确切符合研究区特点的参数设置,灵活多变地选用驱动因子可以有效地帮助实现运用CLUE-S模型同时模拟出"建设用地上山"、"建设用地为耕地腾挪土地"、"建设用地沿河沿路发展"、"重点产业用地扩张"等多项土地利用政策在空间上的布局,其结果对土地利用变化研究、土地利用规划工作等具有一定意义。     

The elasticity of substitution for land: The effects of measurement errors

The explanatory variable used in most previous studies of land-nonland substitution, assessed or appraised land value, is subject to considerable measurement error. There is evidence that this biases the substitution elasticity from a true value of unity to a measured value in the 0.5 to 0.8 range. An hedonic method of measuring land value is proposed and applied to the Chicago residential sales data developed by Berry and Bednarz. Substitution elasticities are estimated within a CES framework from the two measures of land value; after correction for a vintage effect, appraised land value indicates that the elasticity is 0.57 whereas the hedonic measure of land values supports a unitary substitution elasticity. Therefore, the errors-in-variables hypothesis is confirmed and the use of a Cobb- Douglas production function is suggested.     

城市用地结构与产业结构关联的实证研究——以重庆市为例

城市用地结构与产业结构的有机耦合是提高城市用地效益,促进产业结构高级化和城市整体功能提升的前提和保障。文章利用比例变化指数和Granger因果法对重庆市城市用地结构和产业结构耦合关系的实证研究显示:重庆市城市产业结构变化滞后于城市用地结构变化,城市用地结构变化与产业结构变化的差距呈现先上升后下降的趋势,即重庆市城市用地结构与产业结构的有机耦合在经历了非同步变化后逐渐步入同步变化的轨迹;短期内,城市用地结构变化推动产业结构的优化,随之,产业结构又反作用于城市用地结构;城市用地结构和产业结构同步变化轨迹还没有出现,这说明城市用地结构与产业结构互为因果的关系应在长期的调整、协调中才能得以实现。     

A Simple General Test for Tax Bias

A bstract .   The paper infers the biasing effects of taxes from their differential effects on the present values of rival uses for given tracts of land. After-tax wage rates, interest rates, and commodity prices are exogenous, hence not affected by taxes, which are therefore all shifted to land rents and values. The effects are differential among rival uses, hence change their ranking in the eyes of the landowner-manager. Most taxes downgrade the highest use into a lower use, inducing quantum leaps away from higher and better uses into lower and worse uses. The paper uses forestry as an allegory for all land uses. It compares yield taxes, property taxes, income taxes, and site value taxes. It finds that a change from the first three to the site value tax would induce quantum leaps from lower to higher uses of land.