三基地雷达最佳空间定位算法

将三基地雷达二维定位最佳算法加以推广,在不增加设备量的前提下,充分利用各雷达站的测量信息,对三基地雷达三维空间直线布站的最佳算法进行推导和研究.仿真结果显示,空间相关数据压缩算法比独立数据压缩算法更加有效地提高了目标定位精度,特别是较好地改善了发射站附近区域的定位性能,有效解决了双基地雷达空间定位的基线盲区问题.     

基于误差反向传播算法的OFDM系统频域均衡

提出用一种基于神经网络的均衡方法,并用误差反向传播(BP)算法对多层前馈网络进行训练.分析和数值仿真结果表明,基于BP网络的频域均衡方法有较好的均衡效果,并且复杂度不高.     

初相注入式快速符号同步的一种实现方法

通过平方滤波算法对时钟初相进行预估计,实现了Gardner算法下初相注入式符号同步.该方法具有快速、高精度的特点,尤其是较好地解决了初始点为过零点的极端情况下,Gardner算法收敛方向不确定、收敛时间较长的问题.计算机仿真和实际应用证实了该方法的有效性.     

一种一维距离像的识别算法

随着高分辨率雷达的发展,一维距离像识别已成为雷达目标识别的重要方法之一.为了消除一维距离像的平移,将一维距离像变换到频域,提取其频谱信息作为识别特征,并依据Fisher判据,将高维特征空间数据降到一维空间,提高了算法的实时性.仿真结果表明这是一种方便有效的识别方法.     

一种快速的扇束CT滤波反投影重建算法

提出了一种用于扇束CT(计算机断层扫描)重建的快速滤波反投影算法.这种算法是传统标准滤波反投影(FBP)重建算法的加速形式,主要通过减少投影数量然后重建子图像来实现.实验结果表明:对于一幅512×512图像,这种算法可以将重建过程加速40倍以上,并且不会引入明显的图像误差.这种算法也适应于多层螺旋三维重建,并且可以延伸用于三维锥形重建.     

Entry to foreign markets and productivity: Evidence from a matched sample of Turkish manufacturing firms

We examine the effects of international trading activities of firms on creating productivity gains in Turkey by using a recent firm-level data set over the period 2003–2010. We establish treatment models and investigate the productivity improvements of firms through trade by using propensity score matching techniques together with difference-in-difference estimates. Three different groups of treatment are constructed: (1) firms that are involved only with import activities, (2) firms that are involved only with export activities and (3) firms that are involved with both export and import activities. The results of the study suggest that both exporting and importing have positive significant effects on total factor productivity (TFP) and labour productivity (LP) of firms. Importing is found to have a greater impact on productivity of firms compared to exporting. Further, two-way trade is found to have more significant effects than those of one-way trade on firm productivity. Finally, our results indicate that international trade has greater impact on LP rather than TFP of firms.     

The Impact of Market Orientation on the Internationalization of Retailing Firms: Tesco in Eastern Europe

This paper investigates a Western retailer's market orientation levels in two emerging markets. We examine whether the market orientation-company performance link holds true for retailers in emerging economies, despite environmental differences. By using concepts from key studies we have assimilated a fully representative model - applied through interviews with top management from Tesco and its subsidiaries and affiliates in Hungary and Slovenia. Using this example, we find that the market orientation-business performance link is valid for Western retailers in emerging economies. Here, the retailer applied market orientation predominately through; the use of matching with suppliers of own brand goods; top management emphasis on market orientation and risk taking. Intelligence generation and dissemination was exercised via global processes such as brand review.     

复合形遗传算法求解功率优化分配研究

传统遗传算法存在过早收敛及局部搜索能力差的缺点,在求解无线网络协作通信功 率优化分配等NP难问题时难以求得最优解。通过小生境策略解决遗传算法过早收敛问题,引 入复合形法提高局部搜索能力,构造了兼顾广度搜索与深度搜索的高性能混合算法,并对上 述问题进行求解。实验结果表明,所提算法与已有算法相比有一定优势,有效延长了协作网 络寿命,稳定性较好,分配的功率波动范围小。     

Real effects of private equity investments: Evidence from European buyouts

This study investigates the effects of buyout deals on the ex-post performance of target companies. The analysis is based on a sample of 241 private-to-private buyouts involving European companies between 1997 and 2004 and a control sample of non-buyouts selected through a propensity score matching methodology. The paper explores three different dimensions of firm performance: size, profitability and productivity. The results indicate a positive impact of buyouts on the growth of total assets and of employment in target firms in the short- and mid-term. An equivalent clear pattern cannot be identified for productivity, while we estimate a lower operating profitability for buyout companies with respect to the control group three years after a deal is made. When we restrict the analysis to the sub-sample of buyout companies, we find that generalist funds negatively and significantly impact the mean ex-post operating profitability of PE-backed firms, while turnaround specialists are positively associated with operating profitability. The evidence also highlights that target companies whose lead investor is located in the same country show relatively higher ex-post profitability performance.     

Impact of fit,involvement, and tenure on job satisfaction and turnover intention

This study examined the interactive effects of need–supplies fit, job involvement, and job tenure on service sector employees' job satisfaction and turnover intention in Turkey. Survey data collected from 252 employees who worked in three different banks and one logistics company operating in Istanbul, Turkey, confirm the three-way interaction in predicting employees' turnover intention. In particular, the effect of needs–supplies fit on turnover intention was found to be more strongly positive for longer tenured, highly involved employees. Results also reveal that while the three-way interaction does not predict job satisfaction, the two-way interaction between needs–supplies fit and job involvement is significant. Specifically, needs–supplies fit had a stronger effect on the job satisfaction of highly job-involved employees than those with lower levels of involvement. Certain implications of these results, as well as avenues for future research, are discussed.