基于Householder变换的正交PSWF脉冲设计

传统的Schmidt方法对椭圆球面波函数（PSWF）脉冲组进行正交化时,脉冲组的最大互相关值受脉冲个数的影响,同时还存在计算复杂度高的问题。针对上述问题,提出了基于Householder变换的正交化方法,通过将PSWF脉冲离散化,再依次对各离散的PSWF脉冲进行Householder变换,实现了对PSWF脉冲组进行QR分解,并得到新的正交PSWF脉冲组。仿真结果表明,与传统Schmidt方法相比,基于Householder变换的正交化方法使得脉冲组的最大互相关值从10-4降低到10-11,改善了脉冲组的正交性能,突破了脉冲组在脉冲个数的限制,并降低了计算复杂度,同时能够保持PSWF脉冲带内能量集中度高的优势。     

电离层色散效应对宽带BOC信号的影响

电离层色散特性导致宽带二进制偏移载波（Binary Offset Carrier,BOC）信号的码片时域波形和相关函数曲线产生畸变,影响BOC信号完好性和跟踪性能。为了评估电离层对BOC信号传输的影响,构建了宽带BOC信号的电离层影响分析框架,分析了电离层色散效应对码片时域波形和相关特性的影响,并评估了三类典型BOC信号的带内电离层色散效应在码跟踪环路和载波跟踪环路引入的偏差。研究结果表明,电离层色散效应会导致宽带BOC信号时域码片实部和虚部边缘产生抖动现象,色散信号与标准信号间的互相关函数会产生明显的相关损耗;在电离层活跃期间,电离层色散效应在码跟踪与载波相位跟踪中均引入明显的鉴别误差。该结果对BOC信号的电离层误差的评估与校正有一定的参考意义。     

LS曲线拟合下的时差估计

针对时差估计（TDE）易受噪声影响产生模糊的问题,推导了单频信号、线性调频（LFM）信号以及二进制相移键控（BPSK）信号的互相关（CC）函数表达式,以最小二乘（LS）曲线拟合细化CC函数的幅度谱,获取精确的时差估计。首先对CC函数的幅度谱进行谱峰搜索,得到时差的粗估计,然后对CC函数的幅度谱以时差的粗估计为界,根据脉内调制类型,选择相应的一次或二次曲线,进行LS曲线拟合,降低噪声项对信号项的影响,可有效排除伪峰和局部最大,获得时差的精确估计。仿真结果显示,在信噪比大于6 dB时,BPSK信号的时差估计均方根误差接近零。     

基于频-时域的非正弦波通信系统设计方法

为了突破正弦载波通信体制的约束,有效提高系统的频带利用率,提出了基于频-时域的非正弦波通信系统设计方法。采用从频域出发再到时域波形设计的通信系统设计思想,通过构建频域特性函数,反向设计时域脉冲波形;经时域正交脉冲组构建、非正弦时域正交调制,实现了信息的无载波传输。理论分析及仿真结果表明：该方法可使已调信号具有较好的能量聚集性,无需滤波而直接送往信道传输,可有效减少对其它频段用户产生电磁干扰,且系统的频带利用率可快速接近2 bit/s·Hz-1。     

基于幅度调制畸变Wiener模型的OOK辐射源指纹特征提取

通过分析生成On-Off Keying（OOK）信号的发射机系统的幅度调制畸变特性，阐明了OOK信号辐射源特征产生机理，建立了OOK辐射源的幅度调制畸变特性的Wiener模型，并根据信号模型应用差分进化算法完成OOK幅度畸变特性参数的估计，从而构建辐射源指纹特征完成对OOK信号辐射源的识别。仿真试验和实际数据测试表明，该算法具备OOK辐射源指纹特征提取和识别能力，对实测数据中4个OOK辐射源识别率为93%，优于基于暂态幅度特征的提取方法。     

可实时更新任意函数和图形波形的发生器IP核设计

基于直接数字频率合成（DDS）原理、可编程片上系统（SoPC）技术和Avalon总线规范，结合软件编程技术，设计了一个通过PC软件可实时产生任意函数表达式波形和人工图形绘制波形的任意波形信号发生器。该信号发生器包括具有独特调制方法及多功能DDS IP核设计、用于通信控制接口的Nios II软件设计和函数波形产生与图形波形编辑的PC软件与界面设计。给出了4种设计波形与实际输出波形的测试验证结果。在该信号发生器运行时，通过PC端上位机软件可十分方便且实时地更新波形，并通过函数方式与图形方式相结合，真正实现任意波形信号的产生。     

一种适用于强脉冲噪声下的对数型恒模盲均衡算法

针对脉冲噪声下恒模算法(Constant Modulus Algorithm,CMA)失败的问题,通过分析脉冲噪声的影响,提出了一种基于最小均方（Least Mean Square,LMS）准则的对数型恒模算法（Logarithmic-type CMA,LT-CMA）。LT-CMA利用对数函数的非线性变换特性自适应地抑制强脉冲噪声对误差函数的影响,并且利用l2-范数进行信号归一化处理以增强算法的稳健性。仿真结果表明,所提出的LT-CMA可以适应于高斯噪声环境和脉冲噪声环境;与经典自适应均衡算法相比,在收敛速度和稳健性两方面上,所提出的LT-CMA都有显著的提升。     

改进的分布式扩散符号LMS算法

针对无线传感器网络(WSN)中数据运算量大及传输速率受限问题,提出了在分布式扩散LMS算法中先后采用符号函数和改进的符号函数量化策略,实现对误差和估计信号的量化,以减少多节点无线传感器网络的运算量和通信量。仿真结果表明,采用符号函数的量化策略时,误差相对较大;采用改进的符号函数量化策略,在设定适当的量化门限时,所提出的算法性能十分接近非量化的扩散LMS算法,且优于非协作算法。特别对于BPSK信号,相较于传统的扩散LMS算法,性能更为优良。     

基于伪相关函数的cosine-BOC调制信号无模糊跟踪算法

针对余弦二进制偏移载波（cosine-BOC）调制信号自相关函数的多峰特性会导致导航接收机同步阶段产生跟踪模糊度问题，提出了一种基于伪相关函数（PCF）的cosine-BOC调制信号无模糊跟踪算法。该算法通过分析cosine-BOC信号的时域模型，在本地设计两路辅助信号波形，与接收到的cosine-BOC信号进行相关运算，再将得到的两互相关函数利用伪相关函数表达式进行组合，从而消除cosine-BOC信号自相关函数的边峰。仿真结果表明，该算法能够消除cosine-BOC信号鉴相曲线中存在的误锁点，实现伪码无模糊跟踪，提高跟踪可靠性，且该算法适用于任意阶数的cosine-BOC信号。     

基于脉冲形成网络的超宽带脉冲产生与设计

分析了超宽带天线对冲击脉冲波形的要求.利用阶跃恢复二极管和微带传输线.通过延迟的方法设计并制作了超宽带双极脉冲发生器.根据超宽带脉冲发生器产生的脉冲参数,通过理论分析和时域有限差分法(FDTD)仿真,给出了一种微带脉冲形成网络的设计方法,并利用该方法成功地产生了纳秒级宽度的双极性超宽带窄脉冲信号.测量结果表明:经过脉冲形成网络产生的信号具有良好的波形,且拖尾振荡小,有利于提高天线的辐射效率.     

The political market for immigration restrictions: Model and test

This paper addresses the important question of whether public investment spending on economic infrastructure enhances economic growth in Mexico. It estimates a Cobb-Douglas production function that includes public infrastructure capital. Using cointegration analysis, the paper estimates a vector error correction model (VECM) for the 1995?–?99 period. The results suggest that there is a long-term stable relationship among the variables included in the VECM. The evidence also indicates that both public infrastructure spending and private capital formation have a positive and highly significant effect on the rate of output growth. Finally, the impulse response functions (IRF) and the variance decompositions (VDC) of the endogenous variables in the VECM suggest that the response of private capital to public infrastructure is positive while the reverse causation is not affirmed. From a policy standpoint, the findings call into question stabilization policies that disproportionately reduce public infrastructure to meet targeted reductions in the fiscal deficit (JEL, O1, O47, O54).     

PTE,innovation capital and firm value interactions in the biotech medical industry

Unlike previous studies which only focus on the main effect between IC and FV, this research includes PTE with the gap of resource-based view. IC is a key element in creating a competitive advantage, as it has a great influence on FV. A company may put relatively less into IC if it demonstrates higher efficiency. However, previous studies have neglected the fact that relative efficiency and IC affect FV and stock returns directly and indirectly. The research period was from 2006 to 2010 and the main research methods include HRA and DEA. The main research findings include the following. (1) There is a space for improvement in terms of the total technical efficiency. (2) PTE has a significant moderating effect between IC and FV. (3) IC and PTE have a significant influence on FV. (4) Apart from PTE and stock returns, IC and FV show significant differences within the sub-industry.     

通用数据链组网有效性评估的建模

根据现阶段综合信息网络的发展需求,考虑到通用数据链组网的 抗干扰能力强和保密性能高等特征,结合NFE即神经网络（NN）、模糊推理（FR）、专家系 统（ES）模型和 层次分析法(AHP),提出了通用数据链组网有效性研究的N FE-AHP模型,并仿真验证了NFE-AHP模型对于通用数据链组网有效性评估的适用性,结果表 明抗干扰度、鲁棒性、兼容 能力对通用数据链组网有效性评估尤为重要,对于通用数据链组网有效性评估的工程实践具 有一定的指导意义。     

Four decades of negative word-of-mouth and negative electronic word-of-mouth: A morphological analysis

Customers voice their negative brand experiences to their family and friends in the form of negative word-of-mouth (NWOM). Web 2.0 enables the sharing of NWOM in electronic format on various social media sites, online customer review forums, and blogs, which is known as negative electronic word-of-mouth (NeWOM). Researchers need to study the spread of NWOM/NeWOM to prevent adverse consequences for companies and suggest an optimal response for its redressal. Existing literature review studies have focused on word-of-mouth (WOM) and electronic WOM (eWOM) and have considered both positive and negative WOM and eWOM concurrently. Past literature reviews have captured the breadth of the WOM domain, ignoring the depth. This research article contains a review of 282 journal papers capturing the depth of the extant literature by focusing solely on ‘negative’ WOM and eWOM (NWOM and NeWOM), and presents a broad view of the NWOM and NeWOM domains using morphological analysis (MA). This will help to conceptualize and categorize the existing state-of-the-art literature into broad dimensions and identify future research opportunities. The MA framework helps to bifurcate this literature into the following four dimensions: (i) nomenclature of NWOM and NeWOM, (ii) antecedents of NWOM/NeWOM, (iii) impacts of NWOM/NeWOM, and (iv) prevention and recovery response to NeWOM. Further dissection of these four dimensions leads to 15 sub-dimensions and 217 variants. Combinations of the 217 variants enable the identification of 550 novel future research opportunities in the area of NWOM and NeWOM.     

Multinational Enterprises’ Entry Mode Strategies in Syria and Jordan: The Impact of Ownership Advantages

This study addresses the issue of ownership advantages affecting multinational enterprises’ (MNEs) entry mode strategies in developing countries. Although a few studies have focused on such effects, very little attention has been devoted to the ownership advantages generated from the institutional environment of MNEs’ home countries. To bridge this gap, this study concentrates on three types of ownership advantages: intangible asset advantages (IAA), advantages of common governance (ACG), and home‐country‐specific advantages (HCSA). Using a sample of 303 foreign affiliates, this study empirically examines the choice of MNEs between a wholly owned subsidiary (WOS) and a joint venture (JV). The data were collected from senior executives of MNEs’ subsidiaries operating in Syria and Jordan. The findings of this study reveal that MNEs’ choice of entry mode strategies is significantly influenced by intangible asset advantages, advantages of common governance, and home‐country‐specific advantages. Hence, senior executives perceiving an increased importance of these assets will opt for a WOS rather than a JV when entering a new market in the Middle East. © 2015 Wiley Periodicals, Inc.     

FVC方法:评估公司价值的先进方法

为了更好地评估公司价值,介绍一种最近国际上出现的通用性公司价值计算模型,它所采用的算法内核更好地把对公司价值的财务分析与计算机编程技术相结合,从而可以更加有效地进行实际操作,以提高工作效率,节省时间。     

美国国际贸易法院判定美国商务部对河北兴茂轮胎有限公司非公路用轮胎“双反”措施不当案评述

美国进口商和中国出口商不满美国商务部对来自中国的某些非公路用轮胎实施反倾销和反补贴税的裁定,向美国国际贸易法院提出起诉。美国国际贸易法院裁定,美国法律没有明确规定反倾销税法是否可适用于非市场经济国家;本案中美国商务部做的"双反"裁定,在方法上不合理。本文在介绍该案的基本案情、归纳法院推理和判决的基础上,对该案涉及的法律问题做了简要评论。     

基于企业资源计划的价值链管理创新

现代企业竞争是企业供应链之间的竞争。现代企业引入企业资源计划（ERP）系统能够实现对整个企业供应链的管理，突破仅对企业内部资源管理的局限性，适应了企业在价值链管理时代市场竞争的需要。     

内部审计在ERM中的作用机制探讨

良好发挥内部审计的作用能为企业风险管理(ERM)增值,这已经成为不争的事实。本文首先为内部审计在ERM中进行职能定位,指出内部审计在ERM中应该发挥和不应该发挥的作用,进而对内部审计在ERM中如何发挥作用进行探讨。