探地雷达在公路改扩建工程检测中的应用

公路改扩建工程在广东省正处于快速发展时期,如何准确得到路面病害情况,是旧路处治方案制定面临的主要问题.依托开阳高速改扩建工程,采用三维探地雷达对旧路进行病害检测,得到道路表面及内部的病害分布情况,并分别与人工徒步调查路况及开挖后内部实际情况进行比对.结果表明:当三维探地雷达检测采样间距设置为2.0 cm、驻波时间设置为0.6 ms、时窗设置为85 ns时,可达到较好的检测精准度;三维探地雷达可实现对路面结构内部不同深度位置的裂缝病害进行探测,精确识别3 mm宽裂缝,并了解裂缝的发展方向及性质.     

Effects of crisis response tone and spokesperson's gender on employer attractiveness

Timely apologies to key publics on social media are becoming an important aspect of crisis recovery but little is known of how the spokesperson’s characteristics and the tone of apology may influence the outcome. Recognising the importance of the need to attract quality workforce, this study examines the impact of social media response to a preventable crisis on organisational attractiveness. Specifically, a 2 (message tone: corporate/formal vs. human/informal) x 2 (spokesperson’s gender: male vs. female) between-subjects factorial design was used to test the effectiveness of an apology. The results suggest a significant moderated mediation effect. We find that account acceptance mediates the relationship between message tone and organisational attractiveness, and this effect is conditional on gender of the spokesperson. The results are relevant to crisis managers and brand managers that seek to attract and retain talents.     

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。     

Sharing versus collaborative economy: how to align ICT developments and the SDGs in tourism?

Great hopes have been placed in the sharing economy to provide a new business model based on peer-to-peer (P2P) exchanges of underutilized assets. As a model, the sharing economy has been expected to make significant contributions to sustainability, providing new opportunities for entrepreneurship, more sustainable use of resources, and consumer co-operation in tight economic networks. However, in recent years, digital platforms have turned into the most important actors in the global sharing economy, turning global corporations, such as AirBnB, Booking, or TripAdvisor into intermediaries controlling and profiting from most transactions. Focused on accommodation, this paper conceptualizes the sharing economy in comparison to the wider collaborative economy, and discusses its social, economic, environmental, and political impacts in comparison to the sustainable development goals. It concludes that the sharing economy has great potential to make very significant contributions to sustainability, though the model is increasingly being replaced by the collaborative economy, which performs as an extension and acceleration of neoliberal economic practices.     

Social media affordances in entry‐level employees’ socialization: employee agency in the management of their professional impressions and vulnerability during early stages of socialization

This study examined how entry‐level employees interacted with social media during three stages of organizational socialization. They navigated between four different media affordances (persistence, editability, visibility, and association) while experiencing them as both enabling and constraining in different socialization stages. Qualitative interview data analysis revealed during anticipatory socialization, job applicants realized visibility and persistence in relation to institutional and individualized socialization. During encounter, new employees managed personal and professional life boundaries carefully against the association and visibility affordances. Although some participants used both public and enterprise social media for obtaining job‐related information and understanding coworkers and company culture, during metamorphosis, most interviewees adopted passive information seeking strategies and experienced a paradoxical tension between the enabling and constraining affordances of social media. Findings are discussed with regards to employees’ exertion of agency in managing their professional impressions and coping with high levels of uncertainty and vulnerability during early stages of socialization.     

Forecasting dynamic return distributions based on ordered binary choice

We present a simple approach to the forecasting of conditional probability distributions of asset returns. We work with a parsimonious specification of ordered binary choice regressions that imposes a connection on sign predictability across different quantiles. The model forecasts the future conditional probability distributions of returns quite precisely when using a past indicator and a past volatility proxy as predictors. The direct benefits of the model are revealed in an empirical application to the 29 most liquid U.S. stocks. The forecast probability distribution is translated to significant economic gains in a simple trading strategy. Our approach can also be useful in many other applications in which conditional distribution forecasts are desired.     

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。     

地下综合管廊混凝土爆灰检测及加固

针对某市钢筋混凝土地下综合管廊的现浇顶板、侧壁出现的混凝土爆灰质量缺陷,为确保管廊结构的安全使用,采用钻心法、超声波法、沸煮试验、爆灰物质的化学成分分析等检测方法,对爆灰现象进行了检测。结果显示,混凝土中存在的块状氧化钙与水熟化后体积增大1倍~2.5倍,使得混凝土在强度未达到设计抗拉强度前在块状氧化钙体积膨胀应力作用下被拉裂,导致了此类质量缺陷的发生。分析了质量缺陷对管廊结构的影响,并对管廊结构进行了加固设计及处理,满足了结构的正常安全使用要求。研究结果可为类似爆灰缺陷的设计及处理提供参考。