AWGN信道下TH-PPM UWB通信系统性能分析与仿真

首先介绍了TH—PPM UWB信号，然后从理论上对加性高斯白噪声（AWGN）信道下系统的性能进行了分析，包括误码率分析和系统容量分析，最后对系统的误码率和接入用户数进行了仿真比较。结果表明，重复码长度、脉冲重复时间和用户数目的选取对系统的误码率都有较大的影响，同时，系统容量与输出信噪比和数据传输速率有关并趋于定值。     

卷丹百合组培快繁技术的研究

以卷丹百合珠芽为实验材料,以MS为基本培养基,对其组培快繁进行了研究,结果表明,适宜的小鳞茎诱导培养基为MS 1.0mg/LNAA 0.5mg/L6-BA 0.1mg/LKT;适宜的增殖培养基为MS 2mg/LNAA 0.5mg/L6-BA 0.1mg/LKT;适宜的生根培养基为1/2MS 0.2mg/LIBA;诱导和快繁适宜的条件为光照16h/d,温度(25±1)℃。     

一种新型调宽功放电路

本文给出一种新型调宽功率放大电路并从理论上进行详细分析。     

移动通信无线覆盖均匀性分析

本文分析了移动通信系统中电波传播对覆盖均匀性的影响。通过典型路径传播损耗和移动通信系统同频干扰的分析，给出了衡量覆盖均匀性的性能指标。计算机模拟表明了覆盖均匀性与覆盖模式的关系。     

Introducing errors in progress ratios determined from experience curves

Progress ratios (PRs) derived from historical data in experience curves are used for forecasting development of many technologies as a means to model endogenous technical change in for instance climate–economy models. These forecasts are highly sensitive to uncertainties in the progress ratio. As a progress ratio is determined from fitting data, a coefficient of determination R² is frequently used to show the quality of the fit and accuracy of PR. Although this is instructive, we recommend using the error σ_PR in PR, which can be directly determined from fitting the data. In this paper we illustrate this approach for three renewable energy technologies, i.e., wind energy, bio-ethanol, and photovoltaics.     

双通道跟踪接收机对地校相技术

为了解决新建地面测控站的无塔标校技术难题,提出了一种抛物面天线近场对地校 相新方法,在径向距离大于0.3倍远场距离的条件下可实现对地校相功能,通过外场专题试 验研究进行了验证,对靶场测控系统的工程建设具有较高的参考价值。     

An Exploratory analysis of flight delay propagation in China

Delay propagation is the flight departure delay caused by the arrival delay of pre-segment flight. Chinese airline market has suffered very poor on-time performance (OTP) in recent years. It is, however, unclear whether delay propagation prevails as one major source for such problem. This study first aims to empirically quantify delay propagation in the Chinese airline market. Specifically, we shed light on heterogenous levels of delay propagations across different airports and airlines. Then, the distinct delay propagation patterns in China are also discussed and compared with other developed airline markets (e.g., the US and Europe). Our estimation is based on OTP data for over 12 million Chinese flights covering the 2015–2017 period. Specifically, it is found that 10 min arrival delay of pre-segment flight within 1 hr before the departure lead to an average of 7.49 mins delay propagation for subsequent departure flight. Arrival delay of earlier pre-segments (1–2 and 2–3 hr before the departure) leads to much less delay propagation, due to longer ground buffer. Chinese airlines arrange longer ground and flight buffer than that of the US airlines to prevent the delay propagation from accumulating along the subsequent flights in a day. Thus, unlike the US market, delay propagation is not the major reason for poor OTP in China. In addition, delay propagation is less prevailing at the Chinese hub airport. This is because China has relied on point-to-point network, which does not require sophisticated schedule coordination. And the local passengers at these Chinese hub airports have higher time value such that the Chinese airlines also try to improve OTP at these hub airports to better serve these lucrative but time-sensitive local passengers. Unlike the European LCCs, Spring Airlines, the largest low-cost carrier (LCC) in China, outperforms major full-service carriers (FSCs) in controlling delay propagation. This finding may also apply to other Northeast Asian LCCs sharing common operational characteristics as Spring Airlines. Last, we find that airlines purposely tolerate moderate departure delays of up to 15 min, which is the threshold that defines delays, no matter whether the pre-segment flight arrives late or on-time. The relevant policy and managerial implications are also discussed.     

战场环境中的电波传播模型优化选择方法

针对战场级的复杂电磁环境仿真过程中涉及到全频段覆盖、环境影响、仿真速度要求高等问题,提出了一种综合考虑用频装备、环境信息和模型自身特点的电波传播模型选择方法。该方法首先通过频段对用频装备及电波传播模型进行划分,再结合环境信息中降雨量、海拔、植被覆盖率、气候类型、导电特性等参数进行综合分析,最终得到传播模型的优化选择方案。在典型作战场景仿真应用中,该方法为传播模型的合理选择提供了思路,保证了仿真的精度,同时也为电磁环境仿真中传播模型本地化提供了依据。     

金融科技对银行业务的冲击影响——基于VAR模型的实证分析

金融科技加快了银行“金融脱媒”的进程,研究金融科技对银行业务影响作用机理对商业银行的转型至关重要。利用VAR模型分析了2017—2022年商业银行贷款、存款、手续费及佣金净收入及对应市场第三方互联网支付交易规模等季度数据,通过建立VAR模型来分析金融科技对商业银行资产、负债、中间业务的冲击程度和相应解释贡献度。研究发现第三方互联网支付交易规模对商业银行的资产业务在前五期产生了较为明显的反向作用;此外余额宝的货币市场基金以及第三方互联网支付交易两者的联合依次对商业银行的负债、中间业务产生正向、反向的作用。     

系统极化码的置信传播译码性能分析

置信传播（BP）算法可以为系统极化码提供软信息作为判决依据,也可以为系统极化码在级联迭代译码中提供交换软信息。在详细描述基于信道极化结构的置信传播算法基础上,比较了系统极化码在软信息判决方法和极化编码判决方法下错误率性能的差异。仿真结果表明,软信息判决方法可以提高系统极化码的误比特率,在高信噪比下误帧率方面也略有提高。