Local inference for locally stationary time series based on the empirical spectral measure

The time varying empirical spectral measure plays a major role in the treatment of inference problems for locally stationary processes. The properties of the empirical spectral measure and related statistics are studied — both when its index function is fixed or when dependent on the sample size. In particular we prove a general central limit theorem. Several applications and examples are given including semiparametric Whittle estimation, local least squares estimation and spectral density estimation.     

山秀水电站升压站优化设计

山秀水电站的升压站优化布置方案在节省土建及设备投资、满足安全运行的前提下，把110kV GIS布置在变压器硕上。这种做法节省综合造价约52％，缩短工期，可实现提前发电1个月。采用该方案，水电站至今运行良好，取得很好的经济效益，可作为类似工程的参考。     

浅论10kV供电系统的微机保护

本文首先对10kV供电系统的重要作用进行了阐述,在此基础上,概述了微机继电保护的主要特点和类型,并对目前10kV系统中继电保护的配置现状进行了简要的介绍,最后对其发展趋势进行了探讨。     

探讨500kV变电站二次系统的防雷问题

本文阐述了500kV变电站二次回路系统的防雷措施和弱电设备防雷产品的技术措施．并对雷击电磁脉冲入侵弱电设备的雷害机理进行了讨论,给变电站的二次回路系统防雷提供了技术上的参考和建议。同时考虑雷击点的近雷区和远雷区、工频过电压和进线段杆塔冲击接地电阻等因素的影响,从而对雷电侵人波系统进行建模分析。这为防护雷电过电压、保护电气设备提供了有价值的参考依据,为高压变电所雷击保护研究分析提供了有效的方法。     

Does risk management matter? Evidence from the U.S. agricultural industry

This article constructs triple-difference tests around shifts in the supply of risk management instruments available to agricultural producers to reveal a positive relation between risk management and productivity. This relation is more robust when producers adopt instruments with payoffs linked to group performance and weaker when payoffs are linked to individual performance. Additionally, productivity is particularly high among risk-managing producers in counties containing high levels of bank deposits, a proxy for access to finance. Overall, this article illuminates the relation between hedging and real firm outcomes as well as the interaction between access to finance and firms' risk management choices.     

参数差异化500kV单相自耦变压器成组运行适应性研究

三相参数不一致将导致500kV单相自耦变压器运行性能变差,甚至带来安全风险。为了评估参数差异化500kV单相自耦变压器成组运行的性能和风险,结合河北南网500kV变压器的轮换检修,搭建了500kV变压器组的仿真模型,计算了变压器组各序电压、电流、空载环流、低压绕组环流、中性点电流等参数,结合采购标准确定了2台新制334 MVA单相自耦变压器的最佳短路阻抗,进一步分析了变压器三相参数差异对暂态过程的影响,评估了保护误动和拒动的风险。结果表明,在500kV单相自耦变压器组高-中压短路阻抗有名值差异不大的情况下,变压器稳态运行性能较好,该研究为参数差异化的500kV自耦变压器成组运行提供了经验参考。     

Higher education, elite institutions and inequality

We develop a model of higher education to analyze the effects of elite institutions on individual educational decisions and aggregate labor market outcomes. Elite institutions allow the most talented of a given population to separate themselves from the larger pool of agents enrolled in higher education, and to earn the associated wage premium in the labor market. As elite institutions engage in cream skimming, the returns to publicly accessible education decrease, and enrollment in public higher education declines. The resulting effect on income inequality is ambiguous, since elite education increases income dispersion at the top of the income distribution, and decreases income dispersion at the bottom.     

35kV输电线路设计施工技术探讨

从可行性研究分析、初步设计和施工图设计三个阶段分析阐述了35kV输电线路设计过程,并尤其指出了35kV输电线路抗冰设计。针对35kV输电线路施工中遇见的问题,提出了解决这些问题的施工技术。     

The dynamics of land-cover change in western Honduras: exploring spatial and temporal complexity

This paper presents an econometric analysis of land‐cover change in western Honduras. Ground‐truthed satellite image analysis indicates that between 1987 and 1996, net forest regrowth occurred in the 1015 km² study region. While some forest regrowth can be attributed to a 1987 ban on logging, the area of forest regrowth greatly exceeds that of previously clear‐cut areas. Further, new area was also deforested between 1987 and 1996. Thus, the observed land‐cover changes most likely represent a complex mosaic of changing land‐use patterns across time and space. Using satellite imagery from 1987, 1991 and 1996, we estimate a series of models, including binary probit models for each date, and a random‐effects probit model using panel techniques. We also experiment with spatial sampling schemes designed to reduce residual spatial autocorrelation, and qualitatively compare the impact of spatial sampling on model accuracy. Lastly, we find that changes in relative prices, infrastructure improvement, and topography are all significantly related to changing land‐cover patterns.     

Forty Years Development of China's Outward Foreign Direct Investment: Retrospect and the Challenges Ahead

Outward foreign direct investment (OFDI) has increasingly become an important method for China to integrate into the world economy. This paper comprehensively reviews and analyzes policy development and the changing pattern of China's OFDI over the past 40 years. We divide the development into “restricted” (1978–1999), “relaxed” (2000–2016) and “regulated” (2017 onwards) stages. This paper also reviews literature on the impact of Chinese OFDI on China and host countries. Despite its generally positive effects, large‐scale and unbalanced OFDI activities have alarmed Chinese policymakers. Both developing and developed host countries have expressed their concern over national security and the misbehavior of some Chinese overseas enterprises. Therefore, greater supervision and adjustment from quantity to quality growth is necessary for the future development of China's OFDI.