脉冲超宽带测控信号时延精密跟踪方法

脉冲超宽带测控新体制可有效提高测控系统的安全性能，且具有潜在的高精度测距能力。为了实现其高精度测距功能，提出了一种基于延迟锁定环路的脉冲超宽带测控信号时延精密跟踪方法。该方法在传统伪码跟踪环的基础上进行改进，利用基于非相干积分的非线性反馈环路对接收信号的脉冲相位进行精密跟踪。理论分析和仿真结果表明，该延迟锁定环路可以完成对脉冲超宽带测控信号的时延精密跟踪。与直扩测控信号相比，在相同条件下，脉冲超宽带测控信号的时延跟踪相对误差更大，但由于脉冲宽度很窄，在一定载噪比条件下，其测量精度仍可达厘米量级甚至更高。     

多模终端待机低功耗设计

如今的移动通信网络是由多种制式及多个频段融合而成的多模网络，对于商用终端而言，多种难题交织在一起，其中待机时长是必须要解决的一个关键问题。为此，不同于传统增大电池容量的方法，采用降低待机功耗的策略：时域的时隙控制、频域的电流控制、睡眠和唤醒的电源门控制、低频时钟高频化，其中高频时钟校准低频时钟是降低睡眠态功耗的关键措施。这一系列方案的实施，使得终端在多模实际网络环境下的待机电流小于5 mA，终端的待机低功耗达到了有竞争力的商用水平。     

新型船舶自动识别系统设计及其同步算法分析

为了提高船舶自动识别系统（AIS）的容量，提出了基于正交频分复用技术（OFDM）的新型AIS系统设计方案。新系统设计主要包括系统参数设计、系统帧结构设计。新系统链路容量和信道传输速率均较传统AIS系统提高了6倍，实现了频域资源的有效利用。该系统对符号定时偏差和载波频率偏差特别敏感，因此对接收信号的同步处理必不可少，在设计的新系统基础之上提出了一种新的盲估计算法，利用包含在循环前缀内的冗余信息，在多径信道信息未知的情况下，直接通过对接收信号做相关构造一个归一化的相关特性函数，通过此函数可得到符号时延位置和多径信道长度，进而得到载波频率偏差。仿真结果表明在多径信道下该算法也具有较好的性能。     

新型城镇化与都市农业发展耦合关系及时序特征研究——以武汉市为例

[目的]新型城镇化引致都市农业实现高质量发展,都市农业发展倒逼新型城镇化协同高效推进;探究新型城镇化与都市农业发展的耦合互动关系,对加快推动两系统协调发展具有重要意义。[方法]文章基于2006—2017年武汉市新型城镇化与都市农业发展水平的评价指标测度数据,运用耦合协调度模型定量分析了新型城镇化与都市农业发展的耦合关系。[结果](1)新型城镇化与都市农业总体发展水平均呈上升态势,耦合关系显著;(2)两者耦合度C值在0.490左右变化浮动,2008年和2013年耦合度出现最低值和最高值,分别为0.475和0.500;(3)耦合协调度D值处在0.290～0.627,耦合协调等级从中度失调转变为初级协调阶段,且时序演变呈现出小幅波动性、差异性和阶段性特征。[结论]武汉市新型城镇化与都市农业发展水平的耦合协调程度处于不断完善中,时序特征变化明显。为此,武汉市应坚持贯彻实施"以人为本"及城乡融合发展的新型城镇化发展道路,挖掘农业的多种功能以打造都市农业高质量发展的升级版,强化政策扶持的支持力度以保障新型城镇化与都市农业耦合协调发展。     

Home care routing and scheduling problem with teams’ synchronization

The demand for home care (HC) services has steadily been growing for two main types of services: healthcare and social care. If, for the former, caregivers' skills are of utter importance, in the latter caregivers are not distinguishable in terms of skills. This work focuses social care and models caregivers' synchronization as a means of improving human resources management. Moreover, in social care services, several visits need to be performed in the same day since patients are frequently alone and need assistance throughout the day. Depending on the patient's autonomy, some tasks have to be performed by two caregivers (e.g. assist bedridden patients). Therefore, adequate decision support tools are crucial for assisting managers (often social workers) when designing operational plans and to efficiently assign caregivers to tasks. This paper advances the literature by 1) considering teams of one caregiver that can synchronize to perform tasks requiring two caregivers (instead of having teams of two caregivers), 2) simultaneously modelling daily continuity of care and teams' synchronization, and 3) associating dynamic time windows to teams' synchronizations introducing scheduling flexibility while minimize service and travel times. These concepts are embedded into a daily routing and scheduling MIP model, deciding on the number of caregivers and on the number and type of teams to serve all patient tasks. The main HC features of the problem, synchronization and continuity of care, are evaluated by comparing the proposed planning with the current situation of a home social care service provider in Portugal. The results show that synchronization is the feature that most increases efficiency with respect to the current situation. It evidences a surplus in working time capacity by proposing plans where all requests can be served with a smaller number of caregivers. Consequently, new patients from long waiting lists can now be served by the “available” caregivers.     

What role should public firms play in the upstream market?

We investigate the upstream public firm's desirable option of production timing in the vertically related upstream market. We find that multiple equilibria may exist, including the Cournot-type and Stackelberg-type, with different degrees of privatization in the presence of upstream firms' efficiency gap. These equilibrium outcomes are also influenced by the intensity of downstream market competition. We further show the corresponding optimal degree of privatization in different phases of gradual privatization.