Some issues in blockchain for accounting and the supply chain,with an application of distributed databases to virtual organizations

This paper reviews some recent blockchain‐based applications for information capture, distribution and preservation. As part of that review, this paper examines two key concerns with current blockchain designs for accounting and supply chain transactions: data independence and multiple semantic models for the same information distribution problem. Blockchain applications typically integrate database, application and presentation tiers all in the same ledger. This results in a general inability to query information in the ledger and other concerns. Further, since most applications appear to be private blockchain applications, there is a concern of agents needing to accommodate multiple blockchains depending on who their trading partners are and what they request. Finally, this paper uses a distributed database to design a ‘blockchain‐like’ system for virtual organizations.     

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。     

Relative age effects in political selection

We exploit a regression discontinuity design to provide causal evidence of the relative age effect (RAE) on a long-run adult age outcome: Political selection. We find strong evidence of the RAE in politics in Finland. However, the effect is heterogeneous: We find that male candidates born early in the calendar year have a significantly higher probability of getting elected to the parliament but no similar RAE applies to female candidates nor to municipal elections. Moreover, this effect only takes place in the most competitive parliamentary districts and is present only for some parties. We also find that in all the groups where the RAE does not exist, early-born candidates are under-represented suggesting attrition of talent in the candidate placement. Overall, our results show that seemingly artificial cutoffs imposed by the government have persistent consequences even on the selection to the highest positions of power within a society.     

Fiscal rules and budget forecast errors of Italian municipalities

We study the impact of the domestic stability pact on the accuracy of budget forecasts of Italian municipalities. Identification of the causal effect exploits a quasi-natural experiment generated by the removal in 2001 of the fiscal restraints on budget decisions for municipalities with fewer than 5000 inhabitants and by stricter budgetary restrictions and severe penalties for noncompliers in 2002. We find that relaxing fiscal rules had a sizeable impact on budget forecast errors, especially in 2002. In fact, revenue (expenditure) forecast errors for municipalities with fewer than 5000 inhabitants became 26% (22%) larger than in the past.     

Assigning Refugees to Landlords in Sweden: Efficient,Stable, and Maximum Matchings*

In this paper, we investigate the problem of finding housing for refugees once they have been granted asylum. In particular, we demonstrate that market design can play an important role in a partial solution to the problem. More specifically, we investigate a specific matching system, and we propose an easy-to-implement mechanism that finds an efficient, stable, and maximum matching. Such a matching guarantees that housing is efficiently provided to a maximum number of refugees, and that no refugee prefers another specific landlord to their current match when, at the same time, that specific landlord prefers that refugee to their own current match.     

离心式血液泵水力特性设计及其试验研究

借助商业软件NREC开展离心式血液泵的水力特性设计,其设计流量为5 L/min,设计转速为5000 r/min,得到离心叶轮和蜗壳的三维结构设计方案,并针对其全通道网格进行设计工况下三维流场的定常数值模拟研究.对其溶血性指标进行分析,发现离心式血液泵中95％ 区域切应力小于150 Pa,最大切应力小于500 Pa,满足人体对血液泵溶血性的要求.搭建离心式血液泵流量-压升特性试验测试平台,以质量分数为0.06％ 的黄原胶溶液为流动介质进行试验研究,试验结果显示在设计转速下的实际体积流量偏大于设计流量,整体压升在6550 Pa左右.     

Parking futures: An international review of trends and speculation

The explosion of low-cost, on-demand taxi services and the anticipation of an autonomous vehicle future has made transportation the center of debate and discussion for the first time since the massive expansion of the US highway system in the 1950s. Yet the realm of parking boasts innovations and developments far beyond the high-profile issues of TNCs and AVs. Rather, innovation in parking is happening in many cases quietly on a wide variety of fronts, including technology, public policy, and design. This paper serves an overview of emerging trends in parking, primarily within the US context. We identify and outline five developments and the pertinent technologies helping to catalyze change: unbundling parking costs, reducing parking minimums, pricing and allocating curb space dynamically, designing hybrid parking structures, and preparing for the autonomous era and “mobility as a service.” This paper presents these trends with illustrative examples highlighting current practices, governance challenges, and possible future scenarios.