机械加工精度误差分析及改进措施探讨

机械零件是机械产品的内部器官,机械零件的加工精度对机械产品的质量和性能有着直接影响。机械零件加工误差的产生受多种因素的影响,分析机械加工精度误差,对提高机械产品质量和性能意义重大。从机械加工精度误差产生的原因出发,对如何提高机械加工精度提出了一些看法和建议。     

帧同步电路的设计和分析

简要介绍了实现帧同步的几种方法，给出了采用置位同步法的帧同步电路的设计方案，对其状态的转变进行了阐述，并对帧同步电路参数的选择进行了分析。     

鹤煤三矿南大巷大型贯通方案确定及精度分析

阐述鹤煤三矿三水平南大巷南、北段贯通方案的技术措施,并对贯通后进行测量精度评定。     

机动定位平台间时间同步系统的误差分析与控制

高精度双向时间同步是分布式机动无源定位系统的一项关键技术。结合机动平台的特点,对基于伪码相位测量的双向时间同步系统的误差来源和影响误差的因素进行了分析,并针对其中一些引起误差的主要因素给出了控制误差的有效方法。仿真和实测表明,最终可以在机动平台间实现0.2 ns左右的时间同步精度。     

GPS接收机伪码测距方法及误差分析

根据全球定位系统(GPS)的信号特点,介绍了GPS接收机利用L1频段C/A码进行伪码测 距的原理和方法,提出了一种简单、易行的位同步环设计 方法,并与传统设计方案进行了对比。最后,对影响伪距测量值的因素进行了讨论,给出了 误差计算的方法,分析了对测距精度的影响。     

石油价格波动与GDP的动态协整分析和误差模型

国际石油价格的波动是影响我国经济的重要原因之一,给我国的经济走势带来了不确定性的因素。本文应用时间序列分析中的协整理论,对国际石油价格与我国经济增长指标GDP进行了定量的分析,揭示了石油价格对宏观经济指标的影响程度,进而反映了对我国经济增长的影响程度。     

各种估计总体标准差方法的误差分析和比较研究(下)

本文全面地介绍了估计总体标准差的7种主要统计方法:贝塞尔公式法(最为常用)、彼得斯公式法、极差法、最大误差法、最大残差法、较差法和最大方差法。系统地研究了各种估计总体标准差统计方法的由来和原理,严谨地推导出了其标准差系数的计算公式。根据标准差系数大小所反映出的测量精密度高低可分析比较出各种估计总体标准差统计方法的优劣及其适用范围。     

各种估计总体标准差方法的误差分析和比较研究(上)

本文全面地介绍了估计总体标准差的7种主要统计方法:贝塞尔公式法(最为常用)、彼得斯公式法、极差法、最大误差法、最大残差法、较差法和最大方差法。系统地研究了各种估计总体标准差统计方法的由来和原理,严谨地推导出了其标准差系数的计算公式。根据标准差系数大小所反映出的测量精密度高低可分析比较出各种估计总体标准差统计方法的优劣及其适用范围。     

各种估计总体标准差方法的误差分析和比较研究(中)

本文全面地介绍了估计总体标准差的7种主要统计方法:贝塞尔公式法(最为常用)、彼得斯公式法、极差法、最大误差法、最大残差法、较差法和最大方差法。系统地研究了各种估计总体标准差统计方法的由来和原理,严谨地推导出了其标准差系数的计算公式。根据标准差系数大小所反映出的测量精密度高低可分析比较出各种估计总体标准差统计方法的优劣及其适用范围。     

北京市人口结构变动对居民消费的影响研究——基于协整和误差修正模型的实证分析

本文采用1982—2012年时间序列数据,运用协整模型,对北京市人口结构变动和居民消费关系进行实证研究。实证结果表明,从长期来看,北京市人均消费支出倾向、老年抚养系数和少儿抚养系数之间存在正向的长期均衡关系;而从短期来看,过去几年的少儿抚养系数对居民消费产生抑制作用,而老年人口系数则在短期内对居民消费产生推动作用。     

SAR成像系统重频抖动的影响及补偿

合成孔径雷达(SAR)系统要求时间严格同步,从而可利用脉冲间的相干性进行方位处理。推导了重频抖动造成的时间同步误差对SAR成像方位聚焦的影响以及其极限值,并给出了补偿方法。采用实际系统参数进行了仿真验证,并分析了存在重频抖动误差的实际SAR成像雷达系统,实测数据处理和补偿结果验证了理论的有效性。所提方法对实际雷达系统的设计、问题分析和SAR成像处理误差补偿有指导意义,具有较高的实用价值。     

FSK避障雷达的APFFT测距及误差补偿

由于频移键控(Frequency-Shift Keying,FSK)体制避障雷达在动目标分辨与测量上的明显优势,基于FSK体制避障雷达系统的基本原理和结构,通过Matlab建立了测量系统与信号模型,使用全相位快速傅里叶变换（All-phase Fast Fourier Transformation,APFFT)算法进行了相关测量仿真和测量参数计算。通过对不同条件下的仿真结果分析,得出了测量结果误差产生的原因,并提出了相应的误差补偿方法,大大降低了测量误差,使得相对误差降低至0.1%以下。另外,还对多目标的分辨与测量进行了仿真。     

基于劳伦多项式的LAS码构造及性能分析

对基于Hadamard矩阵的LA码和基于劳伦多项式（Laurent Polynomial）的LS码的生成 及相关特性进行研究,从占空比、相关特性、零干扰窗长度、码字总数等方面仿真分析了LA S码的性能,并结合实际应用,理论分析了LAS-CDMA系统与传统CDMA系统的归一化容量,仿 真比较了LAS码和Gold序列在准同步CDMA系统中的误码性能。仿真和理论分析表明：LAS码具 有均匀的零干扰窗（Interference Free Window,IFW）特性;不同主码的互相关函数IFW附 近存在较小的副峰,多址干扰较小;在准同步移动通信系统中,LAS-CDMA抗多址干扰性能 明显优于传统CDMA系统,使用 LAS码比使用Gold序列有更好的误码性能。     

Analytical approximations of local‐Heston volatility model and error analysis

This paper studies the expansion of an option price (with bounded Lipschitz payoff) in a stochastic volatility model including a local volatility component. The stochastic volatility is a square root process, which is widely used for modeling the behavior of the variance process (Heston model). The local volatility part is of general form, requiring only appropriate growth and boundedness assumptions. We rigorously establish tight error estimates of our expansions, using Malliavin calculus. The error analysis, which requires a careful treatment because of the lack of weak differentiability of the model, is interesting on its own. Moreover, in the particular case of call–put options, we also provide expansions of the Black–Scholes implied volatility that allow to obtain very simple formulas that are fast to compute compared to the Monte Carlo approach and maintain a very competitive accuracy.     

建立生态经济区生态补偿机制的分析与思考

近年来,全国经济持续高速发展,在显著提高社会财富和人民生活水平的同时,由于在生态和环境保护方面的结构性政策缺位,造成了生态和经济建设利益相关者的分配不公平.这种生态保护和经济利益关系之间的扭曲,解决的关键是建立和完善生态补偿机制,调整相关利益者的分配关系,促进生态经济区域经济、社会的协调、可持续发展.     

Returnee faculty members,network position and diversification strategy: an analysis of business schools in China

This paper builds on resource-based and network theories to pose an integrative framework for understanding diversification strategy of MBA curricula in Chinese business schools. Using a data set collected from 41 schools offering MBA degrees, we find that returnee faculty members exhibit a curvilinear effect on curricular diversification. We also find that network centrality moderates the relationship between returnee faculty members and diversification in those educational institutions with insufficient returnee faculty members who can nonetheless achieve synergies by utilizing their network connections. These results not only offer explanations on how organizations in developing countries can overcome limited internal resources disadvantages but also provide specific insights into how business schools in China can offset the challenges of improving their education programmes.     

企业党风廉政建设责任追究不到位的剖析与对策

责任追究是企业实行党风廉政建设责任制的关键环节、核心问题.只有建立科学规范的运行机制,坚持事前防范,事中控制,和事后追究的原则,才能保证党风廉政建设责任制的真正落实.但从目前形式来看,很多单位和部门都存在责任追究不到位的情况,严重影响企业党风廉政建设的落实和效果.     

Obtaining a hub position: A New Economic Geography analysis of industry location and trade network structures

We present a linear New Economic Geography model with three regions, one remote region and two regions that entertain a trade agreement with low bilateral trade costs. Only one of these two integrated regions has the outside option to conclude an additional trade agreement with the remote region and to obtain a hub position. We show that the new trade agreement has a substantial impact on industry location and trade patterns and that the effects strongly depend upon level of integration between the initial two regions. It is not always the region with the outside option that profits from using it. Finally, we also show that higher firm mobility may lead to complex dynamics.     

An analysis of prediction error for new prime-time television programmes: a comparative study between the USA and Korea

This study investigates possible factors in prediction error for audience share for new prime-time television programmes in the USA and Korea. While previous studies have focused on the factors affecting the size of a programme's actual audience, little attention has been paid to the accuracy of audience share prediction. A total of 193 new prime-time TV programmes from 1994 to 1997 for the USA and from 1998 to 2001 for Korea were examined. Advertising industry forecasters' predicted audience share, and actual share data were accumulated from Broadcasting & Cable and Weekly Nielsen Reports. Findings show that the ‘Programme Type’, ‘Returning Lead-Ins’ and ‘Returning Lead-Outs’ worked as significant factors for estimating error in audience share in the USA, and ‘Programme Type’ and ‘Programme Length’ played major roles in forecasting error in Korea. The degrees of relationship with forecasting error are consistent with previous studies' findings. Similarities and dissimilarities in prediction error in both countries were found and are discussed in this study.