化肥价格变化对粮食价格的影响研究--基于省际动态面板数据模型的系统GMM检验

基于我国粮食价格与化肥价格变动趋势的分析,运用2006年~2017年省际动态面板数据模型和系统GMM方法,实证检验了化肥价格变动对粮食价格的影响。结果表明:化肥价格变动对粮食价格存在显著的正向影响,在考虑化肥价格影响下,农业生产服务、种子等农资价格对粮食价格也存在显著的正向影响,机械化农具和农药价格对粮食价格不显著,"价补分离"政策对粮食价格存在显著负向影响。因此,在化肥减量行动背景下,适度调控化肥价格,避免化肥价格上升挤占粮农利润,大力发展农业生产性服务业和种子业,继续实行"价补分离"政策,提高补贴精准性,减少农民投入成本。     

双平行线阵的快速一维DOA估计

针对传统子空间算法需要进行特征值分解或奇异值分解等复杂计算的问题，提出一种双平行线阵（Double Parallel Linear Array,DPLA）的快速一维波达方向（Direction of Arrival，DOA）估计算法。算法通过处理互协方差矩阵的第一列元素构造出等效的噪声子空间，再通过求根MUSIC（Multiple Signal Classification）算法得到DOA估计，有效避开了特征值分解或奇异值分解，降低了计算复杂度，提高了运算速度。仿真结果表明，该算法在提高了估计精度的同时减少了估计时间。     

相关信噪比对天线组阵相位估计性能的影响

传统天线组阵理论为了简化分析，均假设反正切相位鉴别器是一种最大似然估计器，其估计方差能够达到克拉美-罗下界。然而当相关信噪比在中等值以下时，这一假设条件不再适用。为此，分析了相关信噪比对相位估计性能的影响。针对传统天线组阵合成性能分析方法在描述低相关信噪比条件下相位估计性能方面存在的问题，通过引入修正因子，得到了相位估计方差的理论公式，实现了对低相关信噪比条件下相位估计性能的准确描述。     

Shrinkage Estimation Strategies in Generalised Ridge Regression Models: Low/High-Dimension Regime

In this study, we suggest pretest and shrinkage methods based on the generalised ridge regression estimation that is suitable for both multicollinear and high-dimensional problems. We review and develop theoretical results for some of the shrinkage estimators. The relative performance of the shrinkage estimators to some penalty methods is compared and assessed by both simulation and real-data analysis. We show that the suggested methods can be accounted as good competitors to regularisation techniques, by means of a mean squared error of estimation and prediction error. A thorough comparison of pretest and shrinkage estimators based on the maximum likelihood method to the penalty methods. In this paper, we extend the comparison outlined in his work using the least squares method for the generalised ridge regression.     

Small Area Estimation for Disease Prevalence Mapping

Small area estimation (SAE) entails estimating characteristics of interest for domains, often geographical areas, in which there may be few or no samples available. SAE has a long history and a wide variety of methods have been suggested, from a bewildering range of philosophical standpoints. We describe design-based and model-based approaches and models that are specified at the area level and at the unit level, focusing on health applications and fully Bayesian spatial models. The use of auxiliary information is a key ingredient for successful inference when response data are sparse, and we discuss a number of approaches that allow the inclusion of covariate data. SAE for HIV prevalence, using data collected from a Demographic Health Survey in Malawi in 2015–2016, is used to illustrate a number of techniques. The potential use of SAE techniques for outcomes related to coronavirus disease 2019 is discussed.     

Public spending,public governance and economic growth at the Vietnamese provincial level: A disaggregate analysis

This study examines the role of economic governance in the relationship between public spending, private investment, and economic growth in Vietnam at the provincial level. The study data consist of sixty-two Vietnamese provinces for the period 2006–2015. Some notable results are attained by applying a sequential (two-stage) estimation. First, the marginal benefits to economic growth of increased Vietnamese provincial government expenditures may be constrained because of the inefficiency of expenditures on education, business services, and public administration. Second, public spending and private investment are found to be substitutes at the provincial level. Third, based on the Provincial Competitiveness Index (PCI) ranking, used as a proxy for provincial public governance in Vietnam, the significance of public governance can be observed. The study concludes that good governance, characterized by different attributes, such as lower informal charges, greater transparency, and unbiased policy, plays a critical role in improving the impact of government expenditure on economic growth in Vietnamese provinces, particularly through its interactions with private sector investment.     

"十四五"规划时期中国需要开展农民工市民化攻坚战

农民工市民化攻坚战是要在基本实现社会主义现代化新阶段的15年内使得近两亿已经和将要在城镇稳定就业的农民工中的大多数基本上成为市民；其必要性在于，这是新阶段基本实现社会主义现代化的客观要求、基本实现高质量新型城镇化和优化城乡结构的主要任务、更好地解决“三农”问题的重要措施、促进城镇发展和稳定的有益途径，是农民工市民化更有效的战略措施，也有助于推动全面深化改革、有效扩大内需；其可能性在于，无论从资金筹集方面来看，还是从制度改革创新方面来看，都基本具备实现农民工市民化的条件；其主要战略措施包括，由党和国家统一规划部署、综合配套、协调推进，实行市民化和回乡创业就业双管齐下的战略方针，以相关制度改革创新和有效筹集使用相关资金为战略重点等。     

我国煤炭波动周期分析与近中期发展趋势推演

通过对我国改革开放以来GDP增速、煤炭消费增速历史数据的分析,发现不管是经济发展,还是煤炭发展过程中都存在周期性的波动变化规律。而通过对煤炭与经济波动曲线的拟合,发现煤炭与经济发展呈协同波动变化。基于以上煤炭与经济协同波动规律,对未来煤炭与经济发展走势进行了推演,发现煤炭消费增速最早要在2015年前后才能企稳提高,由此进入新一轮上升期。综合分析表明,煤炭抗波动能力较弱,未来要实现煤炭平稳发展,需根据经济发展节奏的不断变化,及时主动地调整煤炭发展步伐,从而避免因煤炭发展的冒进或硬着陆给煤炭及关联产业发展带来长时间、高强度的冲击和损害。     

Theory-Driven Choice Models

We explore issues in theory-driven choice modeling by focusing on partial-equilibrium models of dynamic structural demand with forward-looking decision-makers, full equilibrium models that integrate the supply side, integration of bounded rationality in dynamic structural models of choice and public policy implications of these models.     

DIFFUSION MODELS FOR EXCHANGE RATES IN A TARGET ZONE

We present two analytically tractable diffusion models for an exchange rate in a target zone. One model generalizes a model proposed by De Jong, Drost, and Werker (2001) to allow asymmetry between the currencies which is often an important feature of data. Estimation of the model parameters by the method of Kessler and Sørensen (1999) using eigenfunctions of the generator is investigated and shown to give well-behaved estimators that are easy to calculate. The method is well suited to the models because the eigenfunctions are known so that explicit estimating functions are obtained, and because the state space is a finite interval, for which it is known that the method can be made arbitrarily efficient by including sufficiently many eigenfunctions. The model fits data on exchange rates in the European Monetary System well. In particular, the asymmetry parameter is significantly different from zero for three out of four currencies. An alternative diffusion model is presented with similarly nice properties, but with different dynamics that allow constant volatility near the boundaries of the target zone. No-arbitrage pricing of derivative assets is considered, and the effect of realignments is briefly discussed.