基于灰色关联分析的公路工程造价估算研究

目前分析公路工程造价相似性问题过多依赖于主观经验判断法,缺乏有效合理的定量方法,本文利用灰色关联度分析原理,提出一种分析公路工程造价相似性的定量方法。首先选取相似案例库,采用熵值法求出该案例库的重要属性特征权重值,再计算出相似案例库与待估案例的灰色关联度,最后得出待估案例的公路工程造价估算值,并通过实例证明该估算模型研究的可行性。     

博物馆类建筑工程费用估算研究

如何将建设资金控制在批复限额内,防止“三超”现象的出现,是博物馆类建筑投资估算编制的难点。分析博物馆类建筑的设计特点,梳理博物馆类建筑工程费用估算编制中的应注意的问题,总结出其不同于一般公共建筑工程费用构成的特点,旨在为博物馆类建筑工程费用估算的编制提供借鉴。     

Linking of sample data to small areas

We consider methods for estimating the means of survey variables in domains of a finite population, where sample sizes are too small to obtain reliable direct estimates. We construct generalized compositions from the direct and traditional design-based synthetic estimators and propose the methodology for evaluating their coefficients. This methodology measures similarities among sample elements and estimates of the domain means. We propose the compositions for two cases of auxiliary information: domain-level characteristics are available; true means of auxiliary variables are available for the estimation domains, and unit-level auxiliary vectors are known for the sample elements. In the simulation study, we show where the generalized compositions improve the traditional synthetic and composite estimators.     

Do fiscal rules cause better fiscal balances? A new instrumental variable strategy

This paper estimates the causal effect of fiscal rules on fiscal balances in a panel of 142 countries over the period 1985–2015. Our instrumental variable strategy exploits the geographical diffusion of fiscal rules across countries. The intuition is that reforms in neighboring countries may affect the adoption of domestic reforms through peer pressure and imitational effects. We find that the mere existence of fiscal rules correlates with lower deficits, but the positive link disappears when endogeneity is correctly addressed. However, when considering the strength of rules through a continuous index of fiscal rules’ design, we show that well-designed rules have a statistically significant impact on fiscal balances. We conduct several robustness tests and show that our results are generally robust and not affected by weak instrument problems.     

Structural current accounts in the European Union countries: cross-sectional exploration

This paper investigates structural determinants of the current account balance and assesses whether the current accounts in the European Union countries were consistent with the calculated structural current accounts between 1995 and 2017. We estimate current account regressions using cross-sectional data for 94 countries in 2008–2016 and confirm the main findings with panel data estimates. We document that the current account depends on the real exchange rate in a nonlinear way. The real exchange rate affects the current account at low income levels, but it ceases to be important at high income levels. Based on structural current account estimates for the European Union countries, we document that after the 2008 crisis current accounts adjusted towards structural current accounts in deficit countries, but persisted above structural current accounts in surplus countries.     

经济密度、人口规模与环境污染——基于城市面板数据的实证分析

选取2005-2016年285个地级及以上城市数据,利用静态和动态短面板模型分析经济密度和人口规模对环境污染的影响,分析表明:经济密度与环境污染之间存在“倒U型”关系,人口规模扩大会抑制污染物排放;不同等级城市经济密度、不同规模城市人口对环境污染的影响方向一致,但影响程度有所差异;前期污染排放对当期具有正向影响,环境污染物排放存在路径依赖;经济发展水平、工业产值占比和对外开放也是影响污染物排放的重要因素,但各指标对三类污染物排放的影响方向和影响程度存在差异。据此认为,在综合考虑城市具体空间区位条件下,人口适度集聚,提高城市经济密度,优化产业结构以及加强环境监管是环境治理的重要方向。     

Semiparametric time series models driven by latent factor

We introduce a class of semiparametric time series models (SemiParTS) driven by a latent factor process. The proposed SemiParTS class is flexible because, given the latent process, only the conditional mean and variance of the time series are specified. These are the primary features of SemiParTS: (i) no parametric form is assumed for the conditional distribution of the time series given the latent process; (ii) it is suitable for a wide range of data: non-negative, count, bounded, binary, and real-valued time series; (iii) it does not constrain the dispersion parameter to be known. The quasi-likelihood inference is employed in order to estimate the parameters in the mean function. Here, we derive explicit expressions for the marginal moments and for the autocorrelation function of the time series process so that a method of moments can be employed to estimate the dispersion parameter and also the parameters related to the latent process. Simulated results that aim to check the proposed estimation procedure are presented. Forecasting procedures are proposed and evaluated in simulated and real data. Analyses of the number of admissions in a hospital due to asthma and a total insolation time series illustrate the potential for practical situations that involve the proposed models.     

Duration of price promotion and product profit: An in-depth study based on point-of-sale data

Anecdotal evidence has shown that retail price promotions can help small and medium-sized retailers enhance their sales, and thus profits. However, most marketing managers usually stop a promotion after a certain duration. This study aims to explain why these retailers discontinue their price promotion. Our approach posits that overall contributions of a price promotion to the product profit progressively diminish with time. In this study, we present a theoretical framework to explain the relationship between duration and profit effects of price promotion and propose statistical models to empirically examine this framework using point-of-sale (POS) data. Our findings provide empirical support that the effect of price promotion on the product profit has a downward trend with elapsed time. The results are helpful for marketers to understand how price promotions dynamically influence product profit and when the promotion should be terminated.     

京津冀城市群土地经济密度时空格局演变与驱动因素分析

[目的]研究2006—2016年京津冀城市群土地经济密度的时空格局演变特征及其驱动机制。[方法]以京津冀城市群153个县区为例,运用空间自相关分析、热点分析、地理探测器等研究方法,对土地经济密度的时空演变规律及其驱动因素进行探讨。[结果](1)2006—2016年京津冀城市群县区和地市的土地经济密度及其发展速度在空间上均呈"东高西低,南高北低"格局,但随时间变化区域差异逐渐缩小;(2)Moran′s I指数由0.013 9上升至0.065 3,表明在空间上存在空间集聚状态,且随时间不断优化,区域一体化趋势逐渐增强;(3)空间集聚特征明显,热点显著区集中于北京、天津等经济优势区,并向四周梯度扩散;(4)人均GDP、当年实际使用外资额、固定资产投资额等经济类因子对土地经济密度的解释力较大,且任意两因子交互后作用力优于单项因子作用力。[结论]可为京津冀城市群土地资源的合理利用和差别化调控提供参考。     

Moral hazard and subsidized crop insurance

Along with adverse selection, moral hazard is one of the major hurdles that private and public insurance plans must contend with. Moral hazard occurs if risks are endogenous to a producer's behavior and if the insurer is unable to properly monitor the insured. We review the role of moral hazard in the US crop insurance program. We conduct an empirical analysis of one important aspect of the US crop insurance program—prevented planting. This provision provides indemnity payments if conditions are not suitable for planting. The program has been the subject of considerable controversy, especially during 2019, when the rate of claims is expected to be especially high. Because loss adjustors may encounter difficulties in assessing the weather conditions associated with prevented planting claims, the program is susceptible to moral hazard. We consider the extent to which prevented planting claims may be endogenous to prices. We find significant evidence of moral hazard. The likelihood of prevented planting claims increases as the expected market price decreases or as fertilizer costs increase for corn and soybeans in the Prairie Pothole Region and for grain sorghum and cotton in all states.