某类高阶偏微分系统离散谱的估计

考虑某类高阶偏微分系统离散谱的估计,利用谱理论、矩阵运算、分部积分、测试函数、Ray—leigh定理和不等式估计等方法,获得了用前n个谱来估计第n＋1个谱的上界的不等式,且其估计系数与区域的几何度量无关,其结论是文献[4—5]的进一步推广．     

差异性消费需求——巴拉萨—萨缪尔森模型的一个扩展

巴拉萨-萨缪尔森效应指出,一国在长期的经济增长过程中实际汇率会出现升值。2005年7月21日人民币汇率改革以来,人民币兑美元汇率呈现出单边升值的趋势,且目前人们对人民币汇率形成了强烈的升值预期。因此,运用巴拉萨-萨缪尔森效应研究人民币实际汇率具有一定的借鉴意义。鉴于传统巴拉萨-萨缪尔森效应的分析仅限于供给层面,文章引入了差异性消费需求这一假设条件,在不改变原模型核心假设的基础上,从供需双方面进行了拓展分析,并得出了更加符合现实意义的结论。此外,文章利用中美两国1990～2007年的数据,进行了实证分析。实证结果显示,改进后的模型显著增强了对人民币实际汇率的解释力。     

协同通信系统中差分调制在Rayleigh衰落信道中的误码性能分析

根据源-中继-目的节点链路的等效信噪比模型,推导了检测传送和选择检测传送两种 协议下目的节点瞬时信噪比的概率密度函数和特征函数,基于此推导了协同DMPSK调制近似 误符号率的闭合表达式。推导结果不含积分表达式,方便计算,为系统设计和功率分配提供 了理论基础。最后通过仿真验证了推导结果的正确性。     

积分第一中值定理的证明与推广

本文根据积分上限函数的性质利用微分中值定理证明了积分第一中值定理,用改进的介值定理证明了ξ∈(a,b),并推广了积分第一中值定理。     

A revisit on real interest rate parity hypothesis – simulation evidence from efficient unit root tests

A set of unit root tests are applied to test the existence of long-run real interest rate parity among the G-10 countries over the period 1971M1 to 2007M2. Rather than trusting the asymptotic distributions, this article uses simulation techniques to establish the small sample distributions of these tests, conditional on the stationary and nonstationary processes. The empirical results indicate that the tests have stable finite-sample sizes and higher size-adjusted powers such that the two estimated processes can be distinguished from each other. Thus, for six of the nine countries, their series are more likely to come from the estimated Autoregressive (AR) stationary process than from the nonstationary process. Noticeably, the testing results are rather different from those using the asymptotic distributions, in which only three countries support the real interest rate parity.     

三种电离层射线追踪自导引算法比较

通过建立电离层模型和地磁场模型,采用龙格库塔法求解Haselgrove方程,得到相应的射线路径参数,实现了电离层三维射线追踪。针对射线追踪无法进行自导引计算,分别采用牛顿差分自导引算法、基于变分方程的牛顿法以及单纯形法实现了射线追踪的自导引,并给出了详细的算法分析。重点对变分方程及其二阶微分的求解进行了详细推导。最后对以上三种自导引算法进行性能比较,仿真结果表明:基于变分方程的自导引算法优于其他两种自导引算法。     

国有部门与非国有部门的工资差异及影响因素研究

基于CGSS数据，利用Heckman样本选择模型对中国国有部门与非国有部门的工资差异和影响因素进行系统研究。回归结果显示，国有部门员工的教育收益率高于非国有部门，教育收益率与学历水平呈现正相关关系，与非国有部门相比，国有部门中大学本科及以上学历员工的教育收益率更高。工资差异分解结果表明，两部门全样本工资差异中市场歧视占比高于特征差异占比，与全样本相比，大学本科及以上学历员工的工资总差异和特征差异占比更高，系数差异占比更低，说明高学历群体中部门间工资差异更为明显，而且两部门中仍存在较严重的劳动力市场分割和就业歧视问题。因此，政府应努力消除劳动力的流动性障碍，深化国有部门市场化改革，制定更为合理的工资机制，以促进中国经济的持续健康稳定增长。     

International borrowing without commitment and informational lags: Choice under uncertainty

A series of recent studies in economic growth theory have considered a class of models of international borrowing where, in the absence of a perfect investment commitment, the borrowing constraint depends on the historical performances of the country. Thus, a better level of past economic activity gives a higher reputation, thereby increasing the possibility of accessing the international credit market. This note considers this problem in a stochastic setting based on the volatility of the internal net capital. We study how the optimal consumption level and the maximal expected welfare depend on the combined influence of the trajectory of past economic variables and the volatile environment. In particular, we show how the strength of the history effect and the relative weight of the historical performance depend on the degree of risk.     

平面任意力系的平衡方程及应用——高职教学中一道典型的例题

平面任意力系的平衡方程及应用是教学的重点和难点,它是解决物体系统平衡问题的基础,学生应理解并熟练掌握。本文举一典型例题来说明平面任意力系的平衡方程的三种形式的具体运用。     

The equilibrium exchange rates of European currencies and the transition to euro

This study estimates the demand system using Japanese micro data and calculates the cost of living index (COLI) to assess the substitution bias in the Consumer Price Index. The estimated bias during the sample period of 1982–2000 is about 0.06 percentage points, which is larger than the estimates calculated from a superlative index. The difference between the COLI and a superlative index can be explained with the upward movements of the average utility level in Japan, since the cost of living for the rich has grown more rapidly than that for the poor.