一种用于水声传感网的MAC层协议

针对分簇的水声传感网,提出了一种基于时分多址（TDMA）的MAC层协议——Cluster-TDMA。该协议主要由规划阶段和传输阶段组成。规划阶段,首先由网关节点规划能造成簇间干扰的子节点的传输,其次由各簇头节点分别规划本簇内其他子节点的传输;传输阶段,子节点根据规划表周期性地向簇头节点发送数据,这些数据最终汇聚到网关节点。该协议简单有效地解决了引起簇间干扰子结点的传输规划问题。C++仿真实验表明,该协议具有良好的吞吐率和能量效率性能。     

Repetitive disclosures in the MD&A

This study is the first to empirically analyze repetitive disclosures in the Management Discussion and Analysis (MD&A) section of the 10‐K filing. Repetitive disclosures refer to the extent that content in the MD&A is repeated from the audited financial statement notes. I empirically analyze repetitive disclosures in the MD&A section of the 10‐K filing, and find that firms tend to use more repetitive disclosures when firms have a new CEO, a high level of new disclosures in the notes, issued equity, and have missed the prior year's earnings benchmark. These findings suggest that not all managers use repetitive disclosures to simply obfuscate disclosures. Rather, some managers use repetitive disclosures to emphasize firm‐specific events, consistent with the succession hypothesis. The Securities and Exchange Commission (SEC) states that repetitive disclosures are uninformative and that such disclosures decrease the informativeness of other disclosures in the MD&A. Casting doubt on the SEC's comments, in my primary analyses, I find that repetitive disclosures are informative to investors; this result is stronger for individual investors. Overall, my results suggest that repetitive disclosures are informative, and such disclosures may be effective tools for providing information to investors.     

基于粒子群优化的数字波束形成算法

波束形成的加权系数求解是一个优化过程,现有算法大多经过多次迭代,计算量大,实现复杂。为降低波束形成算法复杂度,将粒子群优化原理应用于数字波束形成中,提出了基于粒子群优化的自适应数字波束形成算法。该算法将每一组权值作为一个粒子,将阵列加权和的输出信号与干扰噪声比(SINR)作为适应度函数,通过比较各个粒子的适应度值,进行迭代搜索得到最优解。该算法可使天线阵在主波束对准有用信号,同时能有效抑制两个以上的干扰,且对阵列通道误差有较好的稳健性。计算机仿真验证了算法的有效性。     

税收手段在产业结构政策中的定位分析

税收手段是产业结构政策的间接干预手段之一。随着经济的发展,间接干预手段在产业结构政策中的作用将日益增大。在产业结构政策的间接干预手段中,税收有着独特的优势,是不可替代的,同时税收手段也不可避免地具有一定的局限性,因而需要与其他手段相互补充和配合,以共同发挥作用。     

课堂教学中汉语对英语习得的影响

汉语对英语习得在起着促进作用的同时 ,更明显地表现出对英语习得的干扰。创造良好的英语学习环境以减少对学习者思维方式的影响尤为重要。     

射频干扰对消技术的系统设计与仿真分析

针对现有大型电子信息系统中同平台接收设备受到同平台发射设备的发射干扰情况 ,研究了可对消发射设备干扰的射频干扰对消技术。分析了射频对消技术的理论模型, 提出了射频对消技术的系统设计方案,重点研究了信号调整、信号检测和系统控制3个主要 单元的设计和系统控制算法。系统仿真结果验证了该系统设计方法的正确性。该系统设计方 法可用于进行后续的样机研制。     

航空通信系统试飞过程中的电磁兼容性评估

电磁兼容性(EMC)是航空电子产品的主要性能,也是实现系统功能的重要保证。试飞试验是 按照预想实现一种思想而提供最终证据的在机载真实环境条件下进行飞行试验,并通过试飞 数据分析结果评估系统效能,所以,EMC预测是航空电子系统试飞评估主要内容之一。论述 了基于电磁拓扑（Electromagnetic Topology）理论分析的航空通信系统EMC评估方法,该 方法已在航空通信系统试飞中被采用。     

Building brand knowledge structures: Elaboration and interference effects on the processing of sequentially advertised brand benefit claims

Two experiments are reported that examine the effects of an ad campaign designed to link two different benefit claims to a brand. The findings indicated that recall for a subsequently advertised claim depended on the strength of existing brand–benefit links in memory. If prior advertising strongly established a benefit claim in memory, then proactive interference effects inhibited the recall of subsequently advertised benefit claims unrelated in meaning. Additional analyses suggested that these interference effects appeared to be a result of difficulties with encoding the newly advertised claims. If the original benefit claim was not as strongly established in memory, however, then unaided recall of the subsequently advertised benefit claims was actually higher than if there had been no prior advertising at all. In fact, less accessible and memorable claims, whether they preceded or followed more accessible and memorable claims, enhanced recall of the stronger claims. Additional analyses suggest that these elaboration effects occurred because prior or subsequent advertising improved brand awareness and thus later brand claim recall as a result.     

Stated Attribute Non‐attendance in Successive Choice Experiments

Attribute non‐attendance in choice experiments affects willingness‐to‐pay (WTP) estimates and therefore the validity of the method. A recent strand of literature uses attenuated estimates of marginal utilities of ignored attributes. Following this approach, we propose a generalisation of the mixed logit model, whereby the distribution of marginal utility coefficients of a stated non‐attender has a potentially lower mean and lower variance than those of a stated attender. Model comparison shows that our shrinkage approach fits the data better and produces more reliable WTP estimates. We further find that while reliability of stated attribute non‐attendance increases in successive choice experiments, it does not increase when respondents report having ignored the same attribute twice.     

浅析PCB设计中的电磁兼容性

针对PCB设计中的板层类干扰、布局类干扰和走线类干扰,详细分析了抑制电磁干扰的分层对策、布局规则和走线准则,并提出了电磁兼容预测分析,以实现PCB设计中的电磁兼容性。