直接序列扩频系统多音扫频干扰性能分析

为有效干扰直接扩频通信系统,通过分析扫频信号及多音信号在干扰直扩通信系统时 存在的优缺点,提出了一种针对直扩通信系统的多音扫频干扰技术。该方法将直扩通信系统 的频谱划分为若干个子频谱,针对每个子频谱采用扫频信号进行干扰。理论分析和仿真验证 表明,该方法可以明显改善扫频干扰直扩通信系统时扫频时间过长以及多音干扰依赖音调位 置的缺点,具有良好的干扰效果。     

多步数据加密技术及应用

数据加密是保护数据安全的一种有效的方法,它是将一段明文按某种算法进行处理,使其成为密文,以保护数据不被非法人窃取、阅读。数据加密技术常分为"对称式"加密与"非对称式"加密两类。多步加密算法属对称式加密,由于安全性高得到广泛应用。     

草土围堰施工方法

草土围堰是临时围堰常用的办法,防渗漏较好且经济实用。文章详述了草土围堰施工的具体要求、施工工序和方法,指出了施工过程中容易发生的问题及处理措施。     

一个K次Fibonacci数列{Fn^k}n=1^∞的线性恒等式

证明了k次Fibonacci数列{Fnk}n∞=1中连续的k＋2个数的线性恒等式并给出具体公式。     

Timing is everything: A meta-analysis of the relationships between organizational performance and innovation

The relationship between innovation and firm performance has been uncertain. In previous empirical tests of both causal directions of the organizational performance and innovation relationship, the temporal sequence of research designs has often been flawed. We meta-analytically test both temporal sequences of this relationship using 158 effect sizes from 55 empirical studies. We find that many empirical studies hypothesized one temporal sequence (e.g. innovation and future performance), but used data based on the opposite temporal sequence (e.g. past performance and innovation). Correcting the studies based on the actual temporal sequence used reveals that while the relationship between innovation and future performance is positive (based on economic rent-seeking), the relationship between past performance and innovation is less clear, especially when the study's framing is taken into account. Focusing on temporal sequencing suggests new research avenues on the organizational performance and innovation relationship.     

Spillovers and absorptive capacity in the decision to innovate of Spanish firms: the role of human capital

This paper investigates whether the existence of knowledge spillovers and the capacity of firms to assimilate them, which we relate with R&D intensity and some human resource management practices, are associated with the decision to innovate of Spanish firms. In order to do this, we employ data from the ‘Central de Balances’ database, which covers both manufacturing and services firms during the period 2003–2007, and use an estimator proposed by Wooldridge [2005. Simple solutions to the initial conditions problem in dynamic nonlinear panel data models with unobserved heterogeneity. Journal of Applied Econometrics 20, no. 1: 39–54] for dynamic random effects discrete choice models. The empirical exercise provides evidence on the positive link between spillovers and the innovative behaviour of companies, not just for the knowledge generated in the same industry, but also for that generated in the same region or by the public sector. Moreover, this link is stronger for those firms with a higher capacity to absorb those spillovers. This ability not only works through firms’ R&D capabilities, but also through factors such as the quality of the labour force, the share of temporary employment and the amount of resources spent in training. In addition to these factors, we find that innovation performance exhibits a high degree of inertia. Further, some other observed firm characteristics, such as size, sales growth, export behaviour, sector capital intensity or financial structure variables, are also found to be relevant determinants of the likelihood of innovation.     

危险化学品泄漏事故的混沌动力学特性分析

为探讨如何有效地预防和控制危险化学品泄漏事故,运用混沌理论方法对焦作市某化工厂泄漏事故统计数据进行了时间序列分析和R/S分析,指出危险化学品泄漏事故具有明显的混沌特性。分析和讨论了危险化学品泄漏事故的混沌特性,并对后续短期内可能发生的事故进行了预测。     

Continuous rainbow options on commodity outputs: what is the real value of switching facilities?

We develop real rainbow option models to value an operating asset with the flexibility to choose between two commodity outputs. We provide a quasi-analytical solution and a numerical lattice solution to a model with continuous switching opportunities between two commodity outputs, taking into account operating and switching costs. The models are applied to an illustrative case, demonstrating that the quasi-analytical solution and the lattice approach provide near identical results for the asset valuation and optimal switching boundaries. We find that the switching boundaries generally narrow as prices decline. In the presence of operating costs and temporary suspension, however, the thresholds diverge for low enough prices. A fertilizer plant with flexibility between selling ammonia and urea is valued in an empirical section using our real option models. Despite the high correlation between the two alternative commodities, ammonia and urea, there is significant value in the flexibility to choose between the two. Both strategic and policy implications for stakeholders in flexible assets are discussed, with some generalisations outside the fertilizer industry.     

莺山地区登娄库组层序地层与油气勘探意义

应用层序地层学的理论和方法,针对研究区的地质概况,综合分析地震、测井、岩心等资料,对莺山地区的层序界面进行识别,共识别出5个三级层序界面(SB1-SB5)。研究区的登娄库组是一套完整的超层序,共发育三个体系域,自下而上为低水位体系域、水进体系域、高水位体系域。在层序格架内,总体以冲击扇、扇三角洲、辫状河三角洲、泛滥平原等相配的沉积体系为主。研究区由下而上共发育3套生储盖组合,表明该区具有一定勘探潜力。     

西安火车站春运车次调度优化

春运期间为尽可能大得满足客运需求,铁路部门需要在各大客运站增添临时旅客列车,春运临时旅客列车的增开需要考虑旅客满意度,经济效益,列车备用数量等因素。本文在现有临时旅客列车增添方案的基础上,结合相关约束条件,建立以旅客满意度最高和增加的列车数量尽可能少为目标的双目标优化模型,并以2013年西安站春运为实例,通过Net平台编写软件计算临时旅客列车的增开数量及调度方案,为优化春运临时旅客列车运行图提供了理论基础。