避免键联接产生装配干涉的公差设计方案

分析了键联接进行装配时产生干涉的具体情况,介绍了保证键联接顺利装配的2种公差设计方案,并对各方案的含义、图样标注和应用特点进行了介绍。     

欧美对华反倾销的演化博弈分析

近年来,中国成为国际贸易中反倾销活动的最大受害国,而欧美是对华实施反倾销的主体．运用演化博弈理论作为工具分析发现,这一反倾销博弈在欧美强、中国弱的非对称时代,欧美的策略必然具有攻击性,中国则较多采取和平策略;而在对称条件下,欧美和中国必然会彼此做出让步以避免各自更大的损失。     

一种新的八参数轴对称组合杂交元的优化方法

组合杂交变分原理中的组合参数的选取是一个难点．基于遗传算法的思想,为能量协调轴对称元组合参数的选取提供了一个方法．数值算例结果表明,这样改进后得到的轴对称元各方面性能很好,数值结果几乎接近精确值．     

The Cyclical Reaction of Fiscal Policies in the Euro Area: The Role of Modelling Choices and Data Vintages*

We survey the recent empirical literature concerning the cyclical response of fiscal policies in the euro area, finding large differences in results. We show that these differences are heavily influenced by the choices made in modelling fiscal behaviour. We make a case for the use, in assessing policies and in the EMU context, of the standard modelling choice where the discretionary reaction of fiscal policy is directly estimated. Models where the overall reaction to the cycle – which includes the effects of both discretionary actions and automatic stabilisers – is directly estimated tend to suggest either strong pro‐cyclical or strong counter‐cyclical discretionary reactions, depending on how this component is identified. Within the standard model and for the years 1994 to 2008, we show that results are significantly affected by the data vintage (ex post or real‐time). With ex post data, we find an unambiguous indication of a‐cyclicality. Using real‐time data, we find that the output gap matters. However, depending on whether we assess policy intentions or actual policies, euro‐area governments' behaviour radically changes. A plausible interpretation is that in the implementation phase, governments loosen their fiscal stance, giving in to political pressures that are proportional to the scale of the economic difficulties in bad times and the size of the ‘growth dividend’ in good times.     

LDPC码在非相干BFSK系统中的性能分析

通过理论分析和计算机仿真研究了LDPC码在非相干BFSK系统中的性能。首先证明单 输入双输出的非相干BFSK系统满足信道对称条件,然后分别利用离散密度进化（DDE）和高 斯近似（GA）算法给出了LDPC码的性能下界,后者与前者相比性能非常接近而且计算量要小 很多。通过仿真得到几种常用LDPC码的性能并与译码门限以及香农极限进行了比较,在相同 码长条件下,度参数为(3,6)的码字具有最优的性能,并且其译码门限距离香农极限只有 约0.67 dB。     

群时延内均衡的模拟滤波器优化设计

为解决滤波器幅频特性算术对称性和通带内群时延波动之间的矛盾,提出了一种滤波 器群时延内均衡优化设计方法,即在网络综合法设计的滤波器电路基础上,将电路与时延均 衡器直接耦合,用最小二乘法使群时延特性逼近一个常数,然后利用无约束优化算法对整个 电路进行优化来降低通带内群时延波动。仿真结果表明,该方法不但能使滤波器幅频特性 算术对称且通带内的群时延特性波动较小,且阶数少、设计方法简单。     

公司治理模式再造研究——以信息对称为视角

百年来公司内部一直延续着股东会、董事会、经理人三层治理结构和监督激励双重治理模式,这种治理结构带来信息不对称并引发监督激励一系列弊端。在信息社会的今天,传统治理模式即将走到尽头,新的治理模式将以信息对称为基点,其最大优势在于重塑委托代理间非合作的博弈关系,再造公司治理模式,而实现信息对称的途径则是"九一十五"方案。论文认为通过对称方案的九大机制、一组数据库、十种技术和五项操作,能够有效制衡ERP信息生成过程,使之只能提供委托人认可的对称的信息,以信息对称摘掉代理人不忠不诚的帽子,消除对会计人做假账、出假表的怀疑,破解审计人事后审计、抽样审计的一贯传统,从而以崭新的治理模式调动各方面的积极性和创造性,实现公司价值最大化。     

Measuring the end of the European financial crisis

In 2013 it was declared that ‘the eurozone crisis is over’. However, in fact, the series of financial crises since 2008 may have interrupted the process of EMU enlargement, which in turn triggered a continuing crisis of confidence in the euro. In this paper we extend the sigma‐convergence test to provide a more precise understanding of real interest rate parity (RIP) convergence. On the basis of this, we predict the timing for eliminating the cost of economic asymmetric shocks. Our estimation indicates the RIP among EMU members and accessions were still valid after the disruptions of the 2008 financial crisis. However, the situation has been even worse since the 2010 European sovereign debt crisis, and ceteris paribus, symmetry cannot be achieved without further policy actions. This implies that the EMU authority must do its best to strengthen symmetry and thereby solidify the EMU, at which point it will be better able to re‐start the process of enlargement.     

科技论文中标题常见问题解析

科技论文的层次标题是高密度信息的载体,相当于文章的躯干。而作者在进行论文写作时拟定的层次标题常常出现不准确、逻辑混乱、上下级标题内容重复等问题。通过举例分析,指出各类错误所在,为科技论文写作时拟定层次标题提供参考。     

Preference symmetries,partial differential equations,and functional forms for utility

A discrete symmetry of a preference relation is a mapping from the domain of choice to itself under which preference comparisons are invariant; a continuous symmetry is a one-parameter family of such transformations that includes the identity; and a symmetry field is a vector field whose trajectories generate a continuous symmetry. Any continuous symmetry of a preference relation implies that its representations satisfy a system of PDEs. Conversely the system implies the continuous symmetry if the latter is generated by a field. Moreover, solving the PDEs yields the functional form for utility equivalent to the symmetry. This framework is shown to encompass a variety of representation theorems related to univariate separability, multivariate separability, and homogeneity, including the cases of Cobb–Douglas and CES utility.