基于联合分析法的城市住区绿地雨水设施 居民喜好度研究

城市化进程带来如城市内涝等诸多环境问题，使得 海绵城市和低影响开发成为热点。城市住区绿地作为城市绿地 的一个重要类型，既是住区居民重要的景观游憩场地，也是海 绵城市低影响开发的重要海绵体，是兼具径流绩效和景观绩效 等综合绩效的复合设施。如何让雨水设施在发挥径流绩效的同 时兼具满足居民需求的景观绩效，是目前相关研究的难点和热 点。居民喜好度的研究是住区绿地雨水设施景观绩效优化提升 的重要方法之一。通过联合分析法，遴选雨水收集、雨水转 输和雨水调蓄3个环节的源头减排雨水设施，模拟江南住区中 心绿地雨水设施场景收集居民评价，进行不同居民群体的设 施喜好度效用值相关性统计和住区绿地不同类型雨水设施效 用值及相对重要性分析。并通过走访、文献查阅解析所得数 据，为住区绿地雨水设施景观绩效提升和低影响开发设计提 供启示和借鉴。     

The development trinity: How regional integration impacts growth,inequality and poverty

Developing countries today have become more active participants in regional trade agreements. This raises questions about how the benefits of integration are distributed, and the extent to which lower‐income countries are able to capture development gains. Historically, such impacts have been difficult to identify with precision. This paper seeks to address this gap by empirically analysing the impact of regional integration on development, particularly the effects on growth and welfare. Using both bilateral and regional integration measures, we show that the ability to capture gains from integration varies across developing country regional groups, with developing Asia benefiting on par with developed countries. The findings in the paper indicate that trade and trade policy play an important role in reducing inequality and poverty in developing countries. It also shows that regionalism can function as a channel to make multilateralism a more adept way of addressing national challenges.     

投资持股关系中的“共享审计师”效应研究

以2007—2015年我国资本市场上具有投资持股关系的上市公司为样本，通过研究持股方和被持股方聘请同一家会计师事务所对持股双方各自审计收费和审计质量的影响，探讨投资持股关系的“共享审计师”中，“信息共享”效应与“低价揽客”效应谁更明显。研究表明，当具有持股关系的两家公司共同聘请同一家会计师事务所后，“信息共享”效应更明显，表现为持股双方的财务报表审计质量和持股方的审计收费显著提升。进一步研究发现：持股双方在不同情况下会选择性价比最高，最有利于自身的方式来获取信息，以谋求“信息共享”效应最大化。     

一种动态加权的LDPC译码方法

为了加快低密度奇偶校验（LDPC）码的译码速度，有效改善LDPC码的译码性能，针对校验节点更新过程中的对数似然比（LLR）值的大小，设计了一种LDPC码的动态加权译码方法。以IEEE 802.16e标准的奇偶校验矩阵为例，根据LLR值的变化规律，利用增长因子和抑制因子对和积译码算法和最小和译码算法进行动态加权。仿真结果显示，基于动态加权的译码方法相对于传统译码方法误码率都有明显改进，译码复杂度也有所降低。     

公司为什么放弃债务的收益呢？

经典资本结构理论认为债务具有税盾效应和财务杠杆效应，因此公司会选择适当的负债以获得债务的税收收益。但是，现实中一些公司的负债很低，甚至为零。公司为什么放弃债务的税收收益呢？本文以2007～2011年中国A股上市公司为研究样本，从行为公司金融的视角分析管理者能力是否导致公司采用“低杠杆”策略。结果表明，中国上市公司存在普遍的低杠杆现象，管理者能力的差异是导致公司采用“低杠杆”策略的重要原因。     

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。     

Stock market volatility forecasting: Do we need high-frequency data?

The general consensus in the volatility forecasting literature is that high-frequency volatility models outperform low-frequency volatility models. However, such a conclusion is reached when low-frequency volatility models are estimated from daily returns. Instead, we study this question considering daily, low-frequency volatility estimators based on open, high, low, and close daily prices. Our data sample consists of 18 stock market indices. We find that high-frequency volatility models tend to outperform low-frequency volatility models only for short-term forecasts. As the forecast horizon increases (up to one month), the difference in forecast accuracy becomes statistically indistinguishable for most market indices. To evaluate the practical implications of our results, we study a simple asset allocation problem. The results reveal that asset allocation based on high-frequency volatility model forecasts does not outperform asset allocation based on low-frequency volatility model forecasts.     

环境公平感知、社会信任与农户低碳生产行为*——以农膜、秸秆处理为例

［目的］研究旨在探讨环境公平感知和社会信任与农户低碳生产行为之间的关系，为促进农户生产行为向低碳化方向转变提供对策建议。［方法］基于陕西和甘肃两省的村域调查数据，以农膜和秸秆处理为例，运用二元logistic模型探讨环境公平感知和社会信任对农户低碳生产行为的影响，并结合分层回归分析了社会信任在环境公平感知和农户低碳生产行为间的调节效应。［结果］（1）在环境公平感知维度中，人际公平感知正向影响农户的农膜和秸秆处理行为； （2）对社会信任来讲，人际信任对农户农膜和秸秆处理行为均有显著的促进作用，而制度信任仅对农户秸秆处理行为具有正向影响； （3）人际信任在种际公平感知和农户农膜处理行为之间具有显著的正向调节效应，而制度信任在两者之间具有显著的负向调节效应； 同样，人际信任在人际公平感知和农户秸秆处理行为之间具有正向调节效应，而制度信任弱化了人际公平感知对农户秸秆处理行为的影响。［结论］环境公平感知和社会信任是影响农户低碳生产行为的关键因素，且社会信任在种际公平感知和农户农膜处理行为之间以及在人际公平感知和农户秸秆处理行为之间具有显著的调节作用。     

Semitractability of optimal stopping problems via a weighted stochastic mesh algorithm

In this paper, we propose a Weighted Stochastic Mesh (WSM) algorithm for approximating the value of discrete‐ and continuous‐time optimal stopping problems. In this context, we consider tractability of such problems via a useful notion of semitractability and the introduction of a tractability index for a particular numerical solution algorithm. It is shown that in the discrete‐time case the WSM algorithm leads to semitractability of the corresponding optimal stopping problem in the sense that its complexity is bounded in order by with being the dimension of the underlying Markov chain. Furthermore, we study the WSM approach in the context of continuous‐time optimal stopping problems and derive the corresponding complexity bounds. Although we cannot prove semitractability in this case, our bounds turn out to be the tightest ones among the complexity bounds known in the literature. We illustrate our theoretical findings by a numerical example.     

一种带辅助译码比特的Polar码译码方法

在传统的Polar码译码的基础上，引入辅助译码比特，构造了一个辅助的Polar码字以提高译码性能。辅助比特由信道选择辅助窗口内的信息位决定。接收端如译码失败，将进行二次译码尝试。译码方案分两阶段进行：基于相同结构的扩展生成矩阵，将辅助译码比特译出；结合译出的辅助比特，对原码字进行译码，提高译码成功率。仿真结果显示，使用所提方法进行译码，其译码性能明显优于普通串行抵消译码方法；与两种传统的自动重传请求方案相比，能分别获得1 dB和1.9 dB的性能增益。