大数据时代进行服务创新的思考

在大数据时代,服务创新必须与超级计算技术密切结合,同时要注意一些应该充分体现的原则。可以开展服务创新的领域是极其广泛的,在经济管理领域,主要可以在企业经营决策、金融理财、商业模式、选择业务外包等诸多领域提供创新的服务。     

Is green growth relevant for poor economies?

To be relevant to developing countries, green growth must be reconciled with the two key structural features of natural resource use and poverty in these countries. First, primary products account for the majority of their export earnings, and they are unable to diversify from primary production. Second, many economies have a substantial share of their rural population located on less favored agricultural land and in remote areas, thus encouraging “geographic” poverty traps. If green growth is to be a catalyst for economy-wide transformation and poverty alleviation in developing countries, then it must be accompanied by policies aimed directly at overcoming these two structural features. Policies and reforms should foster forward and backward linkages of primary production, enhance its integration with the rest of the economy, and improve opportunities for innovation and knowledge spillovers. Rural poverty, especially the persistent concentration of the rural poor on less favored agricultural lands and in remote areas, needs to be addressed by additional targeted policies and investments, and where necessary, policies to promote rural-urban migration.     

一种改进的CPFSK信号频率估计方法

针对突发信号解调中多普勒频偏大的问题，提出了一种改进的连续相位移频键控信号(CPFSK)频率估计方法。首先接收信号平方运算使信号的调制指数加倍，再通过一次离散傅里叶变换(DFT)，用搜索信号平方谱谱峰的方法实现突发信号频率估计。仿真实验表明，在低信噪比条件下，该算法的频率估计精度比经典的相位差频率估计算法提高了20%；该算法与广泛用于高动态突发信号的频率插值估计算法相比，同道干扰信道下信干比改善可达4 dB，DFT长度缩短约1/3。     

Community-based rural residential land consolidation and allocation can help to revitalize hollowed villages in traditional agricultural areas of China: Evidence from Dancheng County,Henan Province

The accelerated rural hollowing driven by vast and increasing out-migration of rural labors under urban–rural dual-track system has imposed huge obstacles on improving land use efficiency and coordinating urban–rural development in China. Taking Dancheng County in Henan Province as an example, this paper analyzes the status quo of rural hollowing and discusses two typical rural residential land consolidation and allocation (RRLCA) practices in traditional agricultural areas (TAAs) of China. The results show that, Dancheng experienced rapid rural hollowing characterized as the hollowing of rural industries, infrastructure, and residential population and settlements. However, Dancheng has considerable potential and the necessity of RRLCA, for the model-based estimation shows that the potential of increasing farmland by carrying out RRLCA was about 5649 ha. The two community-based RRLCA practices show positive effects on the improvement of local living conditions, increment of farmland area and development of rural industries. Their experiences, including self-organized rural planning, democratic decision-making, and endogenous institutional innovation may benefit future RRLCA. Overall, it indicates that promoting community-based RRLCA scientifically according to local conditions could provide an integrated platform for increasing farmland area, developing modern agriculture, promoting new countryside construction, and thus revitalize hollowed villages. On considering the limitations and obstacles of current initiatives, suggestions for future RRLCA in rural China have been put forward.     

Modeling the time varying volatility of housing returns: Further evidence from the U.S. metropolitan condominium markets

This study extends the literature on modeling the volatility of housing returns to the case of condominium returns for five major U.S. metropolitan areas (Boston, Chicago, Los Angeles, New York, and San Francisco). Through the estimation of ARMA models for the respective condominium returns, we find volatility clustering of the residuals. The results from an ARMA‐TGARCH‐M model reveal the absence of asymmetry in the conditional variance. Dummy variables associated with the housing market collapse unique to each metropolitan area were statistically insignificant in the conditional variance equation, but negative and statistically significant in the mean equation. Condominium markets in Los Angeles and San Francisco exhibit the greatest persistence to volatility shocks.     

Robust Markowitz mean‐variance portfolio selection under ambiguous covariance matrix

This paper studies a robust continuous‐time Markowitz portfolio selection problem where the model uncertainty affects the covariance matrix of multiple risky assets. This problem is formulated into a min–max mean‐variance problem over a set of nondominated probability measures that is solved by a McKean–Vlasov dynamic programming approach, which allows us to characterize the solution in terms of a Bellman–Isaacs equation in the Wasserstein space of probability measures. We provide explicit solutions for the optimal robust portfolio strategies and illustrate our results in the case of uncertain volatilities and ambiguous correlation between two risky assets. We then derive the robust efficient frontier in closed form, and obtain a lower bound for the Sharpe ratio of any robust efficient portfolio strategy. Finally, we compare the performance of Sharpe ratios for a robust investor and for an investor with a misspecified model.     

连续钢箱梁桥抗倾覆稳定探讨

通过互通立交(27+41+27)m连续钢箱梁工程,对连续钢箱梁进行计算分析。本次分析采用MIDAS软件建立模型,考虑钢箱梁在最不利荷载组合下的最大内力,进行结构应力和挠度分析。     

新建大同至西安铁路工程皂角大桥连续梁线形控制

本文介绍了皂角大桥(32+48+32m)预应力混凝土连续梁的施工控制情况,提出了一个推算挂蓝弹性变形的简单公式,对控制线性的修缮作出了新的尝试。     

A study on the deployment of high-speed broadband networks in NUTS3 regions within the framework of digital agenda for Europe

This paper investigates the high-speed broadband situation in the EU and its prospects. It uses a deployment model to estimate the investment required to meet the Digital Agenda for Europe (DAE) broadband targets set by the European Commission in its Europe 2020 strategy at different stages: as of 2016, after expected operators’ deployment, after public subsidies and leveraged investment, and as expected in 2020. The model uses data at the NUTS3 level, which is the most granular level that has data available on the status of broadband deployment, to arrive at a coherent and comparable framework. From the different perspectives on the investment to meet DAE targets, the paper concludes on the need for an appropriate combination of incumbent and alternative operators investments, public subsidies and leveraged investments, and new investments, both public and private and non-existing as of 2016, examining their feasibility and the impact of different regulatory, technical, and policy strategies.     

铁路客专现浇连续梁碗扣满堂支架的设计及检算

本文详细介绍成渝客运专线梁滩河特大桥预应力混凝土连续梁现浇施工中碗扣满堂支架的设计及检算,为类似工程施工提供参考。