互联网使用与个体生育意愿——基于信息成本和家庭代际视角的分析

探究生育意愿的影响因素,助力人口转变升级成为当前研究的重要方向.文章置身中国具体情境,基于中国社会状况综合调查数据(CGSS2017),从信息成本视角和家庭代际视角两个维度考察互联网使用对个体生育意愿的影响.研究结果表明,使用互联网以及互联网使用频率越高的个体,其生育意愿越低.进一步研究发现,已育史对于互联网使用频率影响个体再育意愿存在负向调节效应,对于已育个体而言,上网频率越高对再育意愿的抑制作用越加显著;代际"数字鸿沟"对于互联网使用频率影响个体生育意愿也存在显著的负向调节效应.当子代和父辈存在较大的代际"数字鸿沟"时,对于互联网使用频繁的个体,父辈沿袭下来的传统育儿经验和子代通过网络获取的育儿知识相冲突可能会引致更多的家庭矛盾,进而抑制个体生育意愿.反之,当代际"数字鸿沟"较小时,互联网使用频率对个体生育意愿的抑制效应亦有所减弱.文章的发现对于提升个体生育意愿以及生育率的研究具有一定启示意义.     

Foreign direct investment subsidy in a dynamic stochastic general equilibrium model with heterogeneous firms

This study analyzes the macroeconomic impacts of subsidies to attract multinational corporations when firms are determining whether to enter or how to serve foreign markets. We show that a small FDI subsidy scheme induces consumption gains and delivers short‐term welfare improvement for the FDI host country if firms differ in productivity. However, the subsidy generates a new problem and results in the wealth reallocation effect, leading to welfare deterioration for the host country in the long run. Moreover, we find that a subsidy program induces a welfare improvement for the host country if it is offered to all domestic producers instead of foreign producers only in the host country.     

LT码新型度分布及其在电力线通信中的应用

Luby变换(Luby Transform,LT)码作为信道编码应用于电力线通信(Power Line Communication,PLC)，可实现电信号的可靠传输。度分布对LT码编译码性能的影响至关重要。为了得到更优的度分布，首先调整二进制指数分布(Binary Exponential Distribution,BED)中的度数比例，获得一种译码性能更优的改进的二进制指数分布(Improved BED,IBED)。然后，根据IBED在冗余度较小时译码成功率高，而冗余度增大后鲁棒孤子分布(Robust Soliton Distribution,RSD)的译码性能表现更佳的特点，通过求和归一化的方式将IBED与RSD两种度分布的优势进行有机结合，提出一种新型二进制鲁棒孤子分布(Binary RSD,BRSD)。仿真结果表明，与其他方法及传统的RSD相比，采用新度分布进行LT编码，可明显降低译码开销，并节约编译码耗时。将新型度分布应用于基于LT码的PLC系统中，能有效地抑制PLC信道中各种噪声对电信号的干扰，并提高通信效率。     

目的国服务贸易限制政策是否阻碍了中国企业出口规模扩张?

根据经合组织统计的各国服务贸易限制政策条款,先对具体政策条款赋值,接下来加权得到衡量服务贸易限制的STRI指标,最终检验目的 国服务贸易限制对中国企业出口规模的影响.研究发现:在控制引力模型的其他变量以及企业-产品层面的特征变量后,目的 国服务贸易限制政策显著阻碍了中国企业出口规模扩张,且阻碍作用对一般贸易企业、大中型企业更明显.对影响机制而言,服务贸易限制政策造成的固定成本阻碍了企业出口的扩展边际,而引起的可变成本阻碍了企业出口的集约边际,其中,对集约边际的阻碍作用更大;进一步对集约边际分解发现,目的 国服务贸易限制政策降低了企业出口产品数量,但提高了企业出口产品价格.另外,拓展研究发现,目的 国数字化服务贸易开放能够缓解服务贸易限制政策对企业出口的阻碍作用.     

基于AD9361的掌上型LTE RRU设计与开发

当前小体积远端射频单元（Remote Radio Unit,RRU）主要是皮站级别的Pico-RRU，其重量和体积仍然难以满足掌上型的要求。为此，采用高集成度的AD9361芯片来实现长期演进（Long Term Evolution，LTE）宽带收发信机功能，配合时钟同步模块、放大器模块和控制接口电路等一起构建低成本的掌上型RRU。主要解决了基于AD9516的时钟同步、低相位噪声设计和高灵敏度接收机设计三个技术难点，成功实现了掌上型、高性能、低成本的设计目标。整个RRU样机尺寸为18 cm×10 cm×2 cm，质量约500 g，量产成本千元以内。测试表明，该RRU下行误差向量幅度（Error Vector Magnitude，EVM）小于3%，优于3GPP要求的8%；10 MHz带宽时上行接收机灵敏度优于3GPP要求的-93.5 dBm。     

天地一体化信息网络中天基卫星网络架构设计

为了充分利用各种空间设施资源，提升天基信息网络覆盖与传输能力，分别从天基信息网络体系架构和逻辑功能架构角度进行了系统性设计。与以往天基网络的设计不同，该设计更注重各类卫星网络的深度融合应用，为此将网络虚拟化技术引入天基卫星网络。同时，还提出了解决新架构下卫星组网难题的方法，将电磁涡旋、卫星灵活载荷和边缘计算技术设计到天基网络。仿真表明，所提出的架构能有效提升频谱利用率和减少卫星网络信令开销。     

Pricing Defaultable Bonds Using a Lévy Jump‐Diffusion Model

This paper uses a reduced‐form approach to derive a closed‐form pricing formula for defaultable bonds. The authors specify the default hazard rate as an affine function of multiple variables which follow the Lévy jump‐diffusion processes. Because such specification allows greater flexibility in the generation of a valid probability of default, their pricing model should be more accurate than the valuation models in traditional studies, which ignore the jump effects. This paper also proposes a new method for estimating the parameters in a Lévy Jump‐diffusion process. The real data from the Taiwanese bond market are used to illustrate how their model can be applied in practical situations. The authors compare the pricing results for the influential variables with no jump effects, with jump magnitudes following the normal distribution, and with jump magnitudes following the gamma distribution. The results reveal that the predictive ability is the best for the model with the jump components. The valuation model shown in this paper should help portfolio managers more accurately price defaultable bonds and more effectively hedge their portfolio holdings.     

Debt Issue Costs and Issue Characteristics in the Market for U.S. Dollar Denominated International Bonds

This paper analyzes the issue costs and initial pricing of bonds in the international market. In particular, we investigate the determinants of three components of issue costs: underwriter fee, underwriter spread (the difference between the offering price and the guaranteed price to the issuer), and underpricing (the difference between the market price and the offering price). Total underwriter compensation increases with the bonds' credit risk and maturity, but it is insignificantly related to issue size. Interestingly, underwriters appear to price some issue characteristics directly (by adjusting the fee) and other characteristics indirectly (by setting the guaranteed price). The two compensation components (fee and spread) are negatively related to each other. We provide evidence that this trade-off is consistent with income tax considerations, as well as with two-tier pricing by underwriters. We find no evidence of underpricing.     

Intraday Lead-Lag Relationships Between the Futures-, Options and Stock Market

In rational, efficiently functioning and complete markets, returns on derivative and underlying securities should be perfectly contemporaneously correlated. Due to market imperfections, one of these markets may reflect information faster. The use of high-frequency data and the choice for a small unit time interval to measure these lead-lag relations comes at the cost of some or many missing observations, causing traditional estimators to either under- or overestimate covariances and correlations. We use a new estimator to estimate lead-lag relationships between the cash AEX index, options and futures. We find that futures returns lead both options and cash index returns by approximately 10 minutes. The relationship between options and the cash market is not completely unidirectional.