平衡膳食模式视角下粮食需求预测

[目的]随着时代的进步和社会经济的发展,对粮食安全内涵的理解也在逐步深化,粮食安全内涵不仅包括数量方面,还包括营养健康安全,保障居民营养健康成为粮食安全的新时代内涵。基于营养目标的粮食需求研究,建立营养—消费—生产的粮食生产模式,对引导居民合理健康消费和保障粮食安全具有十分重要的意义。[方法]文章首先分析了我国城乡居民营养消费状况,然后基于平衡膳食模式视角,引入标准人消费系数这一概念对我国未来粮食需求进行了更准确的预测。[结果]城镇居民粮食消费已达到高营养目标,但目前农村居民仅达到低营养目标水平,相当于21世纪初的城镇消费水平;考虑人口结构因素,2020年和2030年粮食需求总量分别为4.8亿t和5.6亿t,比没有考虑人口结构变化时分别减少8700万t和2 600万t。[结论]根据分析结果,提出以下几点政策建议:(1)宣传普及营养健康消费知识,引导居民合理膳食;(2)关注人口结构变动,及时调整粮食安全调控机制;(3)优化食品工业的产业机构升级,提高饲料粮转化率。     

基于指数平滑法的组合模型对住房需求量的预测研究

以哈尔滨市2000—2015年的城市人均住房使用面积和总人口数为基础，分别对总人口数建立三次指数平滑法模型，对人均住房使用面积建立二次指数平滑法模型，预测出哈尔滨市未来五年总人口数和人均住房使用面积，将总人口数和人均住房使用面积的预测结果代入M-W优化后的预测模型，更加精准的预测出了哈尔滨市未来五年的住房需求量，并对此提出对策和建议。     

Load profiles and flexibility in operation of washing machines and dishwashers in Europe

While the energy generation system is changing towards the use of more renewable energies, the problem of how to deal with fluctuating energy supply is increasing. Smart appliances in households are often referenced as one possible solution, as their operation may be shifted in time and, thus, used to balance an unstable energy supply. The potential of such appliances has been studied to date mainly in pilot installations with a very limited number of participants or by making assumptions on what might be possible. With this work, a semi‐representative approach for 12 European countries was used to assess actual consumer habits for the use of washing machines and dishwashers which then could be used to calculate average load profiles for those appliances depending on the time of the day. Using these profiles, it is strait forward to calculate how much load may be shifted by those appliances in a demand response application. This allows aggregators or energy utilities to assign clear financial benefits to the shifting potential of those appliances. Consumers use the shifting of appliance operation already today for various reasons. Investigating these reasons allows to learn already a lot about the flexibility of consumers.     

转型期中国土地利用的时序优化与空间释放

随着中国经济快速发展和人口集聚，建设用地需求快速增加，土地供需矛盾日益突出，资源保护和管理的压力逐渐加大。中国经济已步入新常态，经济结构转型倒逼土地供应结构优化调整。发达国家城镇化发展阶段起步较早，在土地节约集约利用与管理方面积累了宝贵经验。结合中国城市土地利用现状，借鉴美国、英国、德国等发达国家土地利用与管理经验，可从盘活存量土地、提高土地供给精准度、建立多元化供地机制三方面实现土地节约集约利用及有效管理，促进供给侧结构性改革。     

The use of open source internet to analysis and predict stock market trading volume

The objective of this paper is to evaluate the impact of information demand and supply on stock market trading volume. Few studies have demonstrated the role of Google search data in analyzing trading volume activity. In this study, we employ a proxy for information demand which is derived from weekly internet search volume. The latest is from Google Trends database, for 25 of the largest stocks traded on CAC40 index, between April 2007 and March 2014. We use news headlines as a proxy for information supply. We use Garch model to analyze and predict trading volume.The empirical results present new evidences. First, information supply has an impact on trading volume but information demand's impact is much more important. Secondly, by applying MCA to results found, it could be concluded that the impact of public information on transaction volume is conditioned by two elements: the firm and market news disclosure and the second element relates to the characteristics of the market participants, more precisely their news interpretations and their risk aversion. Thirdly, we used Chow structural break test to verify the stability of our model. We found that for securities with structural changes, information demand is the responsible variable of the change in our model. Finally, we found that information variables have a predictive power on transaction volume.This paper contributes to existing literature by incorporating open source internet-based data into the analysis and prediction of transaction volume. Using internet information about the stock market, which has appeared recently as an interesting research for financial empiricists, computer scientists and practitioners, will have a very important utility because quantifying demand and supply of information becomes possible.     

Price Endogeneity and Food Demand in Urban China

Price endogeneity has been ignored in previous analyses of food demand in urban China. We exploit data provided by the China National Bureau of Statistics on agricultural commodity supply shifters and use reduced‐form price equations to account for price endogeneity. Applying our unique econometric approach to the analysis of provincial‐level food demand in China, we find strong statistical evidence of price endogeneity. Models that ignore price endogeneity result in substantially biased elasticities and misleading estimates of future food demand in China.     

Pseudo panel data estimation technique and rational addiction model: an analysis of cigarette,alcohol and coffee demands

We use a pseudo‐panel data approach to analyze the relationship between the consumptions of cigarettes, alcohol, and coffee in a rational addiction framework. We find that while cigarette and coffee demands fit well with the rational addiction model, alcohol demand conforms to a model with inventory effects. The results suggest that alcohol consumption increases the marginal utility derived from consumption of cigarettes. Increasing alcohol prices would decrease not only the consumption of alcohol, but also the consumption of cigarettes. On the other hand, increasing cigarette prices do not have the same effect on consumption of alcohol. The cross‐price elasticity of coffee with respect to cigarette price is positive and significant which suggests that coffee substitutes for cigarettes when cigarette prices increase. The cross‐price elasticity of alcohol with respect to coffee price is found to be negative and significant. On the other hand, Morishima elasticities of substitution indicate that cigarette, alcohol and coffee substitute each other along the indifference curve when relative prices change.     

Light fuel demand and public policies in Brazil, 2003–2013

The main objective of this article is to evaluate determinants of demand for light fuels in Brazil between 2003 and 2013. Through a vector autoregression analysis, an effort was made to identify and quantify the impact of different economic variables and public policy measures adopted during this period on the surprising increase in energy consumption by Brazil’s light-vehicle fleet. The results suggest that demand for energy by the light-vehicle fleet was influenced by an increase in income, by a decrease in fuel prices associated with a policy designed to prevent increases in the price of gasoline from pushing the inflation rate up, by a higher availability of credit for buying vehicles, and by a drop in the real price of those goods, with emphasis on countercyclical measures to waive the tax on industrialized products levied on new vehicles during economic downturns in the automotive industry.     

An economic evaluation of market development programmes for US dairy products

‘This study measured the effectiveness of US dairy export promotion programmes on increasing foreign demand and enhancing producers’ revenues. An import demand equation based on panel data was used to test whether export promotion has a positive and significant impact on US dairy exports. The effects of various promotion scenarios on the dairy market were then simulated, and benefit–cost ratios (BCRs) for these programmes were estimated. There were three key findings. First, the combined effort of public and private dairy export promotion expenditures had a positive and statistically significant impact on demand for US dairy products in the world market. The findings indicated that export promotion stimulated total dairy exports by 4.14 billion pounds, on average, per year, which represented 55.8% of total exports. Second, US dairy export promotion has been highly profitable for the nation’s dairy farmers. The calculated BCRs, based on assumed elasticity of supply, ranged from a low of 8.54 for the most elastic assumption to a high of 30.12. Third, from an optimality standpoint, dairy farmers are underinvesting in export promotion. The marginal BCRs ranged from a low of 3.79 to a high of 15.22, which means that, at the margin, increasing export promotion expenditures would be profitable for dairy farmers.     

Effects of carbon emission reduction policies on transportation mode selections with stochastic demand

We are witnessing more frequent extreme weather events due to the global warming. There is an urgent need for governments, industries, general public, and academics to take coordinated actions in order to tackle the challenges imposed by the climate change. It is essential to incorporate the environmental objective in the transportation mode selection problem as transportation is a main contributor to carbon emissions. With this in mind, our paper studies the retailer’s ordering and transportation mode selection problem using stochastic customer demand and investigates the optimal ordering and transportation mode selection decisions under different carbon emission reduction policies. Our analytical results reveal that there are some important transportation mode shifting thresholds under different carbon emissions reduction policies. These findings do not only help firms to make optimal decisions under different carbon emission reduction policies but also support policy makers to develop effective policies on carbon emissions reduction.