Micro-Doppler-based target detection and feature extraction in indoor and outdoor environments

In many cases, a target or a structure on a target may have micro-motions, such as vibrations or rotations. Micro-motions of structures on a target may introduce frequency modulation on the returned radar signal and generate sidebands on the Doppler frequency shift of the target's body. The modulation due to micro-motion is called the micro-Doppler (m-D) phenomenon. In this paper, we present an effective quadratic time-frequency S-method-based approach in conjunction with the Viterbi algorithm to extract m-D features. For target recognition applications, mainly those in military surveillance and reconnaissance operations, m-D features have to be extracted quickly so that they can be used for real-time target identification. The S-method is computationally simple, requiring only slight modifications to the existing Fourier transform-based algorithm. The effectiveness of the S-method in extracting m-D features is demonstrated through the application to indoor and outdoor experimental data sets such as rotating fan and human gait. The Viterbi algorithm for the instantaneous frequency estimation is used to enhance the weak human m-D features in relatively high noise environments. As such, this paper contributes additional experimental m-D data and analysis, which should help in developing a better picture of the human gait m-D research and its applications to indoor and outdoor imaging and automatic gait recognition systems.     

Persistence of innovation in unstable environments: Continuity and change in the firm's innovative behavior

The concept of persistence is generally used to define the positive relationship between past and present innovations, which is explained by feedback and accumulation processes triggered by the firm's past results. This paper states that changes in the economic or institutional conditions of the environment impact on the type of profitable innovations, and past innovations might not be suitable for the new environment. As a result, firm's innovative behavior might change, which means that the firm's set of decisions about engaging in the seek for innovations or not and, if so, the set of investments and capabilities it allocates to innovate could be modified. Empirical evidence is provided to reject the persistence hypothesis and to show that past innovations do not necessarily impact present ones. This paper examines the relationship between past and present innovations for a group of Argentinean firms during 1998–2006, which coincides with a period of macroeconomic instability. Results suggest that persistence has to be analyzed in terms of a dynamic firm's innovative behavior—regardless of its results—and how it allows the firm to accumulate competences and resources, which increases the odds of successfully responding to changes in the environment and continuing to innovate.     

《JSP网络编程》课程实践教学环节教学质量跟踪与评价实施

《JSP网络编程》课程是基于Web动态网站开发的纯实践课程。文章以深化高职教育课程教学改革,提高课程实践教学环节教学质量为宗旨,通过借鉴企业实际动态网站建设的工作过程模式,结合软件工程过程管理理论,遵循质量体系认证标准,引入多方评价机制,对《JSP网络编程》课程的各个实践教学环节进行"以提高实践教学质量为核心"的教学质量跟踪与评价实施,旨在构建一套科学完整且行之有效的实践教学质量跟踪与评价实施体系。     

The innovative performance of firms in heterogeneous environments: The interplay between external knowledge and internal absorptive capacities

This paper investigates the link between firm-level innovative performance and innovation prone external environments where knowledgeable individuals tend to cluster. Organizational ambidexterity and absorptive capacities (potential and realized) make it possible for firms to leverage the availability of external knowledge and boost their innovation performance. The empirical analysis focuses on England and is based on a novel combination of Community Innovation Survey (CIS) firm-level data and patent data. The results show that only firms complementing potential and realized absorptive capacities are able to take advantage of favorable external environments by actively combining internal and external sources of knowledge.     

50年来渭河干流径流变化及其驱动力分析

利用渭河干流林家村、咸阳和华县3个水文站1960年以来的径流资料,应用Kendall秩相关系数、R/S分析、降水-径流双累积曲线法等多种数值模型方法,计算分析了渭河径流的年内分配特征、年际变化特征、径流变化趋势、降水变化和人类活动对径流变化的影响。结果表明：①渭河径流量年内主要集中于5月-10月份,占年径流总量的75%左右;年际变化剧烈,1960年-1970年基本处于丰水期阶段,1994年后基本处于枯水期阶段,其余年份呈丰枯波动;②径流变化趋势现在处于极显著的递减状态（p〈0.001）,递减率处于-17.752（m3/s）/10a至-37.654（m3/s）/10a之间;未来的一段时间内将保持同一势态;③受人类活动和气候变化的影响,渭河径流发生了由多到少的突变;④渭河径流量减少的主要原因是人类活动,降水变化为次要原因     

适于文字复制比后检测的科技期刊编辑出版规范探讨——以2014年CSSCI"新闻学与出版学"期刊为例

【目的】分析科技期刊编辑出版对文字复制比后检测的影响,提出进一步规范和完善编辑出版工作的有效措施。【方法】 研究相关文献及2014年度CSSCI 15种新闻学与出版学期刊,对已发表论文的寄送方式、寄送时差及其对后检测中文字复制比的影响进行统计分析。【结果】 发现文稿的寄收日期、寄送方式对后检测中文字复制率有影响,引证时间未予揭示、引证文献使用不当、引证内容难以核查可能造成文字复制比增高或误判。【结论】 创造性地标识收稿日期,清晰地呈现引证印迹,适当地提供引证样件,有助于检测时确定文字复制的时间终点和准确核对引证内容,为评判合理引证与学术不端扫除障碍,提高编辑出版质量和水平。