Why Do They Keep Coming Back? The Effect of Push Motives vs. Pull Motives,and Attribute Satisfaction on Repeat Visitation of Tourist Destinations

We conjecture that attribute satisfaction, push motives and pull motives will be positively related to return visitation of tourist destinations. We also hypothesize that push factors will be stronger related to return visitation of tourist destinations than pull factors, both directly and indirectly as mediators of the relationship between attribute satisfaction and return visitation. In addition, we predict that age and gender will moderate the effect of push and pull factors on repeat visitation. Finally, we argue that push factors and pull factors will be mutually reinforcing. To test these hypotheses, we conducted an online survey of repeat tourists’ motives, and received 986 complete responses. Survey participants were randomly chosen from a group that met a series or qualifying questions. PLS-SEM analysis of the data showed that, as we hypothesized, attribute satisfaction and push motives were positively related to repeat visitation. In contrast, pull motives were not related to repeat visitation, either directly or indirectly, but did reinforce the effect of push motives; gender did not moderate either push or pull motives and age moderated only pull motives. We discuss the theoretical and practical implications of these findings.     

Crime prediction by data-driven Green’s function method

We develop an algorithm that forecasts cascading events, by employing a Green’s function scheme on the basis of the self-exciting point process model. This method is applied to open data of 10 types of crimes happened in Chicago. It shows a good prediction accuracy superior to or comparable to the standard methods which are the expectation–maximization method and prospective hotspot maps method. We find a cascade influence of the crimes that has a long-time, logarithmic tail; this result is consistent with an earlier study on burglaries. This long-tail feature cannot be reproduced by the other standard methods. In addition, a merit of the Green’s function method is the low computational cost in the case of high density of events and/or large amount of the training data.     

基于卷积神经网络自编码器结构的空时分组传输方案

为提高现有端到端通信系统的泛化能力和可靠性，提出了一种基于卷积神经网络的空时分组码（Space-Time Block Coding，STBC）多输入多输出通信系统物理层方案。该方案将通信系统物理层表述、调制和解调过程联合起来形成端到端自编码器系统，引入多层一维卷积层，分别构建发射机和接收机，并扩展为多天线模式。为进一步提高系统可靠性，合理规划网络结构和参数，联合信号的调制和编码方案，优化了系统模型。仿真实验表明，针对瑞利相关衰落下多输入多输出（Multiple-Input Multiple-Output，MIMO）信道应用场景，训练模型可以实现传统STBC系统的误码性能，两发两收系统在发送端相关系数为0和0.9时分别优于传统系统0.5 dB和1 dB。此外，经过优化后的系统可获得采用卷积编码的性能改善效果，其两发两收不同工作方式优于传统1/2码率卷积编码STBC系统1~3 dB。     

不同调制方式下高斯信道容量的计算

计算不同调制方式下的信道容量对实际通信系统的信道编译码设计具有重要的理论意义。首先从Shannon信息论出发,介绍了平稳无记忆连续信道与加性白高斯噪声信道容量的定义。接着利用互信息与微分熵的相互关系,推导了几种常用的不同调制方式下高斯信道的容量,并给出了相应的信道容量闭合计算表达式。通过将电力卫星通信信道模拟为高斯信道,对采用无速率信道编码联合不同调制方式的卫星通信进行了数值仿真。仿真结果显示,通过推导得到的闭合表达式计算信道容量,能对实际卫星通信的编码速率、译码启动条件的确定起到很好的理论指导作用。     

一种高效的无线自组网全网可靠广播协议

现有大部分的无线自组网广播协议采用最小虚拟骨干子网进行全网广播,能最小化广播的总发送次数。但是,由于未考虑无线链路的不可靠性,这些协议在实际网络中的广播效率并不高。为此,提出了一种高效的全网可靠广播协议（ENWRB）,该协议采用网络编码技术减少单跳广播的重传次数,并通过一种基于链路感知的虚拟骨干网选择算法产生更高效的广播骨干网。仿真结果表明,在确保所有节点成功接收广播消息的相同前提下,ENWRB协议的效率显著高于HCA(Hierarchical CDS-based Algorithm)协议。     

Inked: historic African-American beach site as collective memory and group ‘Third Place’ sociability on Martha’s Vineyard

Using data gained from ethnographic research and interviews, this article examines ‘third place’ sociability in the social interactions of the Polar Bears of Martha’s Vineyard, a group of predominantly but not exclusively middle-aged and senior African-American men and women who swim, exercise and socialise together each morning at ‘the Inkwell’ beach. Using Georg Simmel’s concept of sociability and Ray Oldenburg’s third-place theoretical framework, this study explores the key role of the Monday communal breakfast and the function of conversation in establishing bonds between individuals. It further investigates the promotion of strong feelings of social connectedness, belonging, social support, social capital gains and community among its group members. The ongoing sociability and informal rules of the Polar Bears of Martha’s Vineyard has enabled it to become a model group demonstration of third-place community building. The importance of race, class and place is socio-historically investigated within the broader social context of the popular racialised section of the beach, ‘the Inkwell’, of African-American community life, and within the sub-community milieu of group social interaction.     

Impact of bus rapid transit on housing price and accessibility changes in Sydney: A repeat sales approach

ABSTRACT

New public transport infrastructure is expected to improve accessibility for local residents, and thus contribute to increased land value. The contribution that a bus rapid transit (BRT) system can make to increased land value is less certain than for rail-based systems, with the literature mostly containing bus-based examples from developing countries with extensive BRT networks. This article considers a BRT system named the Liverpool–Parramatta Transitway (LPT) that was implemented in southwestern Sydney in 2003 to improve public transport accessibility in the local area. A repeat sales model is constructed to investigate the impact of the LPT on residential housing prices and accessibility changes using repeat sales data from before and after the opening of the LPT. This identified little price difference between properties close to LPT stations and outside of the area that could be considered as affected by the LPT service coverage. This outcome is at variance with the theoretical underpinning of land value uplift and other empirical evidence relating to the LPT. Hedonic models using the same repeat sales data investigate the study area in more detail, stratifying the sample by housing type and by comparing separate before and after models. These research outcomes identify the extent to which the BRT system has an impact on local housing prices through accessibility improvements to the study area and provide a deeper understanding as to how the quantification of land value uplift from BRT represents one element of the wider economic benefits of a BRT system.     

WSN中基于网络编码的协同点对点信息交换算法研究

针对无线传感器中的节点调度传输问题,提出了一种基于网络编码的协同点对点信息交换算法。由于该算法不仅能够充分利用无线信道的广播特性,而且使用了协同点对点信息交换,从而有效地弥补了PIE算法在数据包的个数大于节点数目的情况下,性能不理想的缺陷,实现了传输次数的减少。仿真结果表明,所提算法的传输有效性明显地优于PIE算法和最少优先算法。     

一种实用的无线信道纠错方法

核心竞争力是企业适应市场的潜力。中国某些企业由于缺乏核心竞争力而使其市场份额逐渐缩小。为了适应国际市场竞争的形势,发展企业核心竞争力是重中之重。为此,除了企业加强自身建设以外,政府应该利用法律和政策,充分利用加入WTO以后宝贵的“缓冲期”,使国内市场尽快完善,促进企业核心竞争力的不断提高。     

POCSAG码的接收与软件译码方法

本文及时追踪世界物流产业发展中出现的第四方物流现象,论述了加入WTO后中国物流产业所面临的严峻形势——跨国公司意图垄断中国的第四方物流市场,而后提出了应对策略。