Ka频段双模航空客舱宽带卫星通信系统总体设计

针对民航市场对客舱宽带卫星通信的迫切需求，提出了一种基于Ka频段高通量卫星的双模解决方案。研究了系统设计的诸多方面，包括卫星资源选择、网络结构、技术体制和适航性。详细介绍了机载设备的组成和双模工作原理，分析了几个与设计实现密切相关的技术指标。方案设计和技术指标分析结果对实际工程应用有一定的参考价值。     

Helping behavior in a virtual crisis situation: effects of safety awareness and crisis communication

Incident evaluations show that bystanders tend to help: they do not wait for professionals to arrive, but act as required by the situation at hand. In the present study, we investigated how safety awareness (induced before an accident happened) and providing a course of action by emergency services affect helping behavior after witnessing a virtual accident with two victims. The main task of the participants was to arrive at a job interview in time. Safety awareness was manipulated by the specific organization they went to: either promoting safe traffic or healthy living. The results show that all participants were inclined to help. Participants who were primed towards safe traffic more often called the emergency number, but talked to the victim less often. Participants who had received specific courses of action moved the victim less often. In all, the results clearly indicate the value of effective risk communication (before an event occurs) and crisis communication (after an event has occurred), as both types of information improve the quality of actual helping behavior at the scene.     

COMMUNICATION ABOUT FUTURE POLICY RATES IN THEORY AND PRACTICE: A SURVEY

We discuss the theoretical rationale for central bank communication about future policy rates, either as part of inflation targeting or in the form of forward guidance. We also summarize both actual central bank communication about future policy rates and empirical evidence on the effectiveness of these types of communication. We argue that there is a disconnect between the theory and practice of forward guidance, as theory assumes commitment on the part of the central bank, while in practice central banks generally do not commit. Future theoretical research on forward guidance should therefore take the absence of commitment by central banks into account.     

冷链物流“最后一公里”快速配送方法研究

冷链物流“最后一公里”的品质配送，对于实现全程冷链以及提升企业形象有着重要的意义。为了实现冷链物流的快速配送，本文提出了一种基于复杂网络的“最后一公里”物流配送区域划分方法。该方法构建了现实生活中物流配送的复杂网络模型，然后基于两阶段的LinkRank社区发现算法实现了物流配送区域的划分，最后建立了一套完善的物流配送体系。该体系明确了配送中转站以及配送点所覆盖的区域，这些区域所包含的社区物流关系紧密、易于配送。本文通过案例研究，验证了方法的有效性，最终方案可有效提高“最后一公里”的配送效率和降低物流成本。     

DSGE pileups

The sampling distribution of estimators for DSGE structural parameters tends to be non-normal and/or pile up on the boundary of the theoretically admissible parameter space. This calls into question both the reliability of asymptotic approximations and the presumption of correct specification. This paper seeks to develop a conceptual framework for understanding how these phenomena arise, and to provide pragmatic methods for dealing with them in practice. The results are presented in three examples and a medium scale DSGE model.     

An Empirical Investigation of the Effects of Rounding on the SPF Probabilities of Decline and Output Growth Histograms

I consider the possibility that respondents to the Survey of Professional Forecasters round their probability forecasts of the event that real output will decline in the future, as well as their reported output growth probability distributions. I make various plausible assumptions about respondents’ rounding practices, and show how these impinge upon the apparent mismatch between probability forecasts of a decline in output and the probabilities of this event implied by the annual output growth histograms. I find that rounding accounts for about a quarter of the inconsistent pairs of forecasts.     

Orientation to sustainability and strategic positioning of destinations: an analysis of international tourism websites

The communication that Destination Management Organizations (DMOs) address to destination stakeholders plays a central role in attracting attention and resources for sustainable destination development and disclosing the efforts made to be a sustainable territory. There has been extensive analysis on the role of official tourism websites that addresses both DMO's internal and external stakeholders. However, less exploration is available on the relationship between the contents disclosed through tourism websites and the strategic positioning of the destination. This study empirically examines that link with a focus on ‘green/sustainable/responsible' travel. Results show a positive association between the orientation to sustainability in online communication and both sustainable regulation of the tourism sector and tourism development. In contrast, there is no significant association with destination size, tourism maturity and pricing policies.     

浅谈在国际传播中的议程设置

International Communication plays an important role in our society. Agenda setting theory emerges from communications studies and focuses on mass media influence on setting political agenda.The theory explains the correlation between the rate at which media cover a story and the extent that people think that this story is important. The media has become a strong barrier of communication between families and the outside world.     

Research agenda for low-carbon mobility: Issues for New World cities

ABSTRACT

Low-carbon mobility (LCM) features strongly in debates about the sustainability of cities and their resilience in the face of demographic, economic, and climate change. Transport is a major source of carbon emissions and there are indications that these continue to increase, despite the considerable recent advances in vehicle, engine, and fuel technologies. Reducing carbon emissions from transport may become more difficult, not easier. A particular issue relates to the New World cities, typified by those of North America and Australasia, which largely developed from the latter half of the nineteenth century onward and whose transportation systems were largely based around private vehicle ownership and usage. These cities are typically composed of low-density, dispersed suburbs, which are highly car dependent and resource and carbon emission intensive. This article develops a research agenda directed at determining and testing policy and planning measures relevant to the quest for low carbon mobility in New World cities. It suggests a rich agenda for essential research on LCM. Much of this agenda falls within the realm of the integration of transport and land use, with attention to urban design details to enhance the perceptions of and opportunities to use low carbon transport alternatives. Research topics identified for LCM research include (1) urban design and land use–transport integration (LUTI), (2) low carbon mobility policies directed at achieving widespread behavior change, (3) opportunities for new technology and its application, including requirements for systems and infrastructure, and (4) analysis and tools for informed decision making, including modeling, measurement, visualization, and especially assessment.