宽带随机混沌雷达高速目标速度估计与成像

随机混沌具有真随机性、对初值敏感、易于产生和控制等特点,频率步进信号易于工程实现和处理,结合两者的优势,提出了一种载频随机步进的随机混沌信号(RSCFSCS)模型,用于高速目标的速度估计和距离维高分辨成像。首先,通过非周期函数激励非线性系统,产生不可预测的随机混沌信号(SCS),经频率调制后用作基带子脉冲。同时,将SCS通过映射变换得到跳频编码(FHC),用来决定调频脉冲串的载频步进。RSCFSCS 速度估计包括粗搜索和精搜索,粗搜索采用固定步长,保证速度偏差小于速度分辨单元,而精搜索采用黄金分割搜索算法可得到精确的速度估计。最后,子脉冲经相干合成形成宽带信号,实现高分辨距离成像。数值仿真表明提出的信号模型和处理算法性能良好。     

Modeling Methods for Discrete Choice Analysis

This paper introduces new forms, sampling and estimation approaches fordiscrete choice models. The new models include behavioral specifications oflatent class choice models, multinomial probit, hybrid logit, andnon-parametric methods. Recent contributions also include new specializedchoice based sample designs that permit greater efficiency in datacollection. Finally, the paper describes recent developments in the use ofsimulation methods for model estimation. These developments are designed toallow the applications of discrete choice models to a wider variety ofdiscrete choice problems.     

Can interest rate spreads stabilize the euro area?

Since the onset of the financial crisis significant interest rate spreads have arisen between euro area countries, both for public and private debt. We check whether these spreads could be made to work towards the goal of providing more stability to the euro area. In particular, we focus on reducing the imbalances that arose between the core and peripheral members of the euro area in the first decade of its existence. The idea is that stable positive spreads in peripheral countries could have decreased domestic demand, preventing the boom–bust cycles that plagued these economies. They could also prevent such developments in the future. We construct a panel model for euro area countries and estimate the relationship between real interest rates and the current account balance. Next, we use the estimated parameters to perform simulations. We find that spreads on real interest rates of 0.6–5.5 percentage points would have been necessary to stabilize external positions of the four peripheral euro area member countries.     

基于期权博弈的PPP项目特许权期决策模型

运用期权博弈方法,从无政府担保基本情形出发,构建 PPP 项目特许权期决策模型,考量政府参与风险分担对特许权期的影响。结果表明,收益波动率一定的情况下,特许权期随着政府最低收益担保期望价值的增加而减少;而在政府最低收益担保期望价值一定的情况下,特许权期随着收益波动率的增加而增加。鉴此,政府应根据项目的风险收益情况实施弹性特许权期制。     

我国钢铁企业技术创新能力分布及演变态势研究

本文依据我国20家大中型上市钢铁企业1998～2013年各项技术创新指标的面板数据,在对企业技术创新能力进行综合评价的基础上,运用非参数Kernel密度估计方法及马尔可夫链分析模型,对我国钢铁企业技术创新能力的分布及发展演变态势进行了研究,研究结果显示：①我国钢铁企业技术创新能力呈现出“单峰→双峰→单峰”的演变规律,钢铁企业技术创新能力水平总体上都得到了一定程度的提高,但不同钢铁企业技术创新能力的发展速度和水平呈现出明显的不平衡性;②不同钢铁企业Kernel密度分布状态与企业所在地区铁矿资源禀赋和工业经济发展水平存在高度关联性;③钢铁企业技术创新能力经过长期发展和积累过程,客观上存在着低水平状态逐渐向高水平状态转移的现实可能性,但由于不同钢铁企业自身的差异性特征,技术创新能力发展将表现出不同步性;④加快企业优化重组和提高生产能力集中度、加强现代高新技术对钢铁产业的改造和升级、加大政府政策引导和科技资金投入是实现钢铁企业技术创新能力快速提升的重要途径。     

Public Debt and Economic Growth in Emerging Market Economies

This paper empirically studies the relationship between public debt and economic growth for selected emerging market economies by performing panel data estimations. The results reveal a statistically significant positive correlation between public debt and the subsequent growth rate of per capita gross domestic product (GDP). Population and investment are also positively correlated with per capita growth, whereas the initial level of real GDP per capita exerts a negative influence on growth, implying conditional convergence. Other variables such as the inflation rate, the trade balance or the exchange rate do not yield a statistically significant effect with respect to economic growth.     

Flexible estimation of price response functions using retail scanner data

Kalyanam and Shively [1998. Estimating irregular pricing effects: a stochastic spline regression approach. Journal of Marketing Research 35 (1), 16–29] and van Heerde et al. [2001. Semiparametric analysis to estimate the deal effect curve. Journal of Marketing Research 38 (2), 197–215] have demonstrated the usefulness of nonparametric regression to estimate pricing effects flexibly. The empirical results of these two studies, however, also revealed that nonparametric regression may suffer from too much flexibility leading to nonmonotonic shapes for price effects. In this paper, we show how the problem of nonmonotonicity can be dealt with without losing the power of flexible estimation techniques. We propose a semiparametric approach based on Bayesian P-splines with monotonicity constraints imposed on own- and cross-price effects. In an empirical application, we illustrate that flexible estimation of own- and cross-price effects can improve the predictive validity of a sales response model substantially, even when price response curves were constrained to show a monotonic shape, as suggested by economic theory. We also discuss the consequences from an unconstrained estimation of price effects.     

一种快速时变自适应信道估计盲方法

提出了一种新的信道估计最小均方(LMS)盲方法--时变步长理想加权判决信道估计盲方法.该方法通过对常规LMS算法进行改进,实现自适应跟踪信道特征变化;同时利用接收机判决误差信息函数作为权系数的理想加权判决,从而解决了常规LMS盲方法收敛速度慢、信道估计性能不高的缺点.仿真证明,对于不同的多普勒频移、时延扩展以及时间,该方法均表现出了比常规LMS方法更优的性能.同时,该方法还可用于航天、雷达等领域估计其他特征参数.     

对转型期中国劳动关系影响的分析

对于转型期中国劳动关系影响的分析，学术界目前大多是从劳动关系内外部因素影响的角度采加以研究的，但却忽视了处于转型期的中国劳动关系对以上诸因素的反作用分析。转型期的中国劳动关系对劳动关系内部构成因素即企业、劳动者和政府有重大影响。     

中美贸易顺差与人民币汇率关系的实证分析

针对中美贸易顺差与人民币汇率关系的问题,本文通过协整分析和Granger因果检验发现,人民币升值在短期难以对中美贸易顺差产生调节作用,从长期影响而言,人民币升值的影响作用也不大。此外,中美贸易顺差在短期还是主要取决于当前贸易收支的现实情况,而中长期则在很大程度上受到美国经济波动的影响。因此,人民币升值不会缓解美国巨大的贸易逆差,而且即使美国贸易收支出现改善也不会对美国经济发展产生显著的正面影响。