房价变动优化分析

为预测未来房价的变动范围,根据往年的房价应用GM(1,1)模型,并结合灰色-马尔科夫模型对房价进行预测。考虑到影响房价的诸多因素变量,对给定的多个因素应用回归分析加以确定。从市场投机因素和政府的调控手段出发优化模型,通过模型分析给出合理的建议。     

政府在耕地减少中的责任和在耕地保护中的作为

集成曲线估计模型和灰色数列模型,研究耕地总量在1983-2006年间的变化过程以及在2010～2020年间的变化态势,分析政府行为在耕地总量减少中的责任和在保护耕地中的作为.研究结果:2020年耕地总量可能低于新的耕地红线,政府对耕地减少负有不可推卸的责任.     

Interlocked Village Markets and Trader Idiosyncrasy in Rural India

The role of traders and traditional exchange institutions has received little attention in empirical research on rural markets in developing countries. We use detailed data on transactions in a village commodity market in India and identify two observed anomalies: first, the repeal of the law of one price, and second, a trader‐idiosyncratic effect, namely that large volumes are sold to a trader who does not offer the best price. Econometric analysis demonstrates that trader idiosyncrasy can largely be explained by reciprocity motives in interlocked village markets. Reciprocity leads to market inefficiencies and can result in unexpected supply responses.     

Factors Affecting the Extent to which Consumers Incorporate Functional Ingredients into their Diets

This study considers the factors that explain the consumption of food and beverages with functional ingredients to avert or offset health problems. We use an instrumental variables Poisson regression model to deal with the endogeneity of perceived health status in functional ingredient use. The first stage results indicate that perceived health status is associated with attitude towards functional foods, food consumption motives and information seeking and being female. The second stage results suggest that individuals who consume more functional ingredients tend to have a positive attitude towards functional foods, are novelty‐seeking, female and older. As expected, consumption of functional ingredients is more likely when consumers’ self‐reports indicate that they are aware of functional foods’ nutritional value and the link with their own health. Consistent with previous research, most of the socio‐demographics are poor predictors of functional ingredient consumption.     

头孢妥仑酯侧链4-甲基-5-噻唑甲醛的合成

研究了头孢妥仑酯侧链4-甲基-5-噻唑甲醛的合成工艺,以丙酮和硫脲为原料,在碘催化下合成2-氨基-4-甲基噻唑,应用Vilsmeiar反应合成2-氨基-4-甲基-5-噻唑甲醛,再经重氮化脱除氨基,得到头孢妥仑酯的侧链,总收率达30%。     

基于快铁融合的上海铁路集装箱快运站选址研究

快铁融合可以充分发挥快递企业和铁路运输的优势,有效提升物流作业效率,达到运输资源分配平衡的效果,是多元化运输的发展方向。在既有和计划建设的铁路货运站中选择铁路集装箱快运站与快递企业集散网络衔接,以快递企业时间满意度和集散运输成本为目标,构建基于时间满意度的铁路集装箱快运站选址模型,以上海铁路集装箱快运站为例进行实证分析,提出保证铁路集装箱快运站与快递企业合理衔接的对策,为铁路集装箱运输融入快递市场提供决策支持,加速快铁融合的实施。     

Investigating the performance of different estimation techniques for crop yield data analysis in crop insurance applications

We investigate the performance of the ordinary least squares (OLS)‐, M‐, MM‐, and the Theil–Sen (TS)‐estimator for crop yield data analysis in crop insurance applications using Monte Carlo simulations. More specifically, the performance is assessed with respect to trend estimation, prediction of future yield levels, and the estimation of expected indemnity payments. In agreement with earlier findings, other estimators are found to be superior to OLS in simple regression problems if yield distributions are outlier contaminated and heteroscedastic. While this conclusion is also valid for subsequent applications such as yield prediction and the estimation of expected indemnity payments, the difference between the considered estimators becomes less distinct. For these applications, we find particularly the M‐estimator to be a good compromise between high‐breakdown (very robust) estimators and the very efficient OLS‐estimator. Because no regression technique dominates all others in all applications and scenarios for error term distributions, our results underline that the choice of the estimation technique should be dependent on the purpose of the crop yield data analysis. However, alternative estimators such as M‐, MM‐, and TS‐estimator can reduce (and bound) the risk of unreliable or inefficient crop yield data analysis in crop insurance applications.     

El Niño,La Niña,and world coffee price dynamics

Coffee is produced in equatorial and subequatorial regions of the world, which are also most affected by El Ni1;o Southern Oscillation (ENSO). ENSO events have a tendency to amplify weather conditions such as droughts or excess precipitation in the affected regions, resulting in production shortage or excess supply, subsequently impacting agricultural commodity prices. In this research we assess effects of ENSO events on world coffee price dynamics using the monthly data between March 1989 and December 2010. We employ smooth transition autoregression framework to examine nonlinear dynamics of ENSO and coffee prices, and illustrate the results of this research using generalized impulse‐response functions. We find that ENSO events indeed have short‐term impacts on coffee prices. The research findings are of interest to coffee producers and intermediaries in the coffee markets as well as researchers in the fields of environmental and development economics.     

1:10000比例尺土地利用景观指数的粒度效应分析

研究目的:基于鹤峰县1:10000土地利用数据,对土地利用数据的景观指数类型及景观水平的粒度效应进行分析。研究方法:GIS和景观格局分析软件应用。研究结果:在类型水平上,景观指数的粒度效应较明显,随粒度的变粗,景观指数可归为单调下降、不规则变化和基本无变化3类;粒度响应最敏感的景观指数为斑块密度;裸地和水田是对粒度响应最敏感的两种土地覆盖类型。在景观水平上,除斑块密度外,其他景观指数粒度效应不明显,斑块密度和面积加权平均分维数的粒度响应最强烈,丰富度指数则最弱。研究结论:粒度效应与所选粒度的变化范围、数据聚合方式、分析景观类型的多少、比例尺的不同都有很大的关系,更深层次的研究需要考虑更加全面。     

A Conjoint/Logit Analysis of Consumers’ Responses to Genetically Modified Tofu in Taiwan

We use data collected from a consumer survey of face‐to‐face interviews to determine consumer demand for genetically modified (GM) tofu attributes in Taiwan. Conjoint analysis using logit models reveals that, on average, brand is the most important attribute in terms of influence on consumers’ preferences, followed by price, with GM content having the least influence. However, the analysis also reveals three distinct market segments for tofu. Apart from the largest segment (which reflects the average lack of concern about GM food), the remaining two segments are split according to their preference or antipathy towards GM tofu. This result suggests that GM labelling is helpful to Taiwanese tofu consumers.