Towards a coherent optical free-space communication system

A coherent optical communication system based on a diode laser pumped Nd:YAG laser with 620 mW single frequency output power has been developed. Differential phase shift keying at a data rate of 565 Mbit/s has been applied. Bit-error-rates of 10/sup -9/ have been measured at a received light power of -46 dBm.<>     

Towards a framework for high-speed communication in a heterogeneousnetworking environment

The issues that are specific to heterogeneous networks are addressed. Some background on both the current ARPA internet model and high-speed packet switching is provided. This discussion includes: the internet components; the internet protocol hierarchy, popularly known as the transmission control protocol/internet protocol (TCP/IP) protocol suite; and the internet strengths and weaknesses. The major elements of an extended internet model that allows internetworking of new high-speed packet networks with a wide range of other networks, including current data networks and national telephone networks, are outlined. Some end-to-end and host interface issues are examined     

Challenging Google Search filter bubbles in social and political information: Disconforming evidence from a digital methods case study

This article engages in the debate on supposed online ‘filter bubbles’ by analysing a panel of Google users’ search results on a standardized set of socio-politically themed search queries. In general, the query results appear to be dominated by mainstream media sources, followed at a large distance by civil society and government resources. By means of mixed model regression analyses, with the prominence of different source types in the search results as dependent variables, it was tested whether search results vary across Google Search users. The results indicate that the inclusion of participants as a random effect does not explain variance when controlling for the different query keywords and the time at which the queries were ran. Hence, this study does not support the occurrence of ‘filter bubbles’ in Google Search results in the context of social and political information.     

Mobile discourse: political bumper stickers as a communication event in Israel

The use of political bumper stickers in Israel began as a spontaneous protest medium, evolving into a routinized form of public discourse, taking place throughout the year, independently of national elections. The rules of interaction of this nontraditional means of political communication are identified and the complex relationships between the messages within their social situation are investigated using an ethnographic model. This analysis reveals that the medium does indeed constitute a structured means of expression with identifiable forms, rules, and usages, affording the person in the street a way of participating in the national discourse, bypassing traditional avenues of influence. The detailed examination of a single political bumper sticker reveals a structure parallel to the overall code, further demonstrating the intricacy of the messages. The analysis shows how this political discourse reflects social norms peculiar to Israel and how its use has become an affirmation of cultural identity. Because the fundamental properties of political bumper stickers have now been exposed, it is possible to examine how the actual use of this medium changes the structure of political agency in society through the presumption that ordinary individuals have the right of access to the public debate of national political issues, a right heretofore exclusively the prerogative of institutional power holders.     

A brief history of mobile communication in Europe

Since the introduction of mobile telephony in the early 1950s in Europe, US and Japan the demand for this service exploded. It seems that the latent demand for mobile telecommunication services for decade’s continued to be very strong. After the introduction of cellular technology the capacity of the services became able to meet the massive demand. Next and future generations of mobile telecommunication technologies bring increased transmission speed and more versatile services. This forces network operators to organise multi sourced information flows supplied by service providers to increase the network effect of the system instead of providing the network infrastructure and leave the content to the users as in pure voice telephony. The drivers and inhibitors behind the emergence and recent developments of mobile telecommunications systems in Europe, are highlighted in this paper. Liberalisation of the telecom markets in Europe drove new entrants to the market and curbed excessive pricing. However, in recent years the lack of challenging service is the main cause for the wavering development of newer generations of mobile telecommunication services.     

Assessing mobile phone communication utility preferences in a social support network

While it is generally accepted that the mobile cell phone has become ubiquitous within society for communicating, the actual use of the utilities on a phone have not been reported. Understanding how communication patterns are changing in society as a result of the mobile cell phone will enable the development and/or modification of existing cell phone utilities, the concept of privacy, and a mobile literacy research domain. To explore mobile cell phone utility use, 99 people completed a mobile phone usage questionnaire. Key results from the questionnaire are physical location when using a mobile cell phone, the length of communication episodes, the usage of phone utilities and existing privacy concerns related to mobile cell phones.     

Internet-based ‘social sharing’ as a new form of global production: The case of SETI@home

Benkler (Sharing nicely: on shareable goods and the emergence of sharing as a modality of economic production, Yale Law Journal, 2004, vol. 114, pp. 273–358) has argued that ‘social sharing’ via Internet-based distributed computing is a new, so far under-appreciated modality of economic production. This paper presents results from an empirical study of SETI@home (the Search for Extraterrestrial Intelligence), which is the classic example of such a computing project. The aim is to explain SETI@home participation and its intensity in a cross-country setting. The data are for a sample of 172 developed and developing countries for the years 2002–2004. The results indicate that SETI@home participation and its intensity can be explained largely by the degree of ICT access (proxied by the International Telecommunication Union’s ‘Digital Access Index’), as well as GDP per capita and dummy variables for major country groups. Some other variables, such as the Human Development Index, perform less well. Although SETI@home is a global phenomenon, it is never-the-less mostly concentrated in rich countries. However, there are indications of a slowly narrowing global SETI@home digital divide.     

Advanced communication technologies and services: Design configuration and stakeholder interests in Europe

Rapid “take-up” in the use of advanced telecommunication technologies and services involves co-ordination between private and public interests in establishing the environment for private investment in new equipment and services to upgrade the existing infrastructure. Alternative scenarios are possible for these developments in Europe. The outcome of this process will depend upon the interaction between public policies and private decisionmaking in several producer and user communities. This paper rejects the consensus view that market forces will suffice in coordinating demand and supply to achieve a socially desirable scenario for future developments. Decisions about the use of technologies and services for addressing social exclusion and redefining the concept of “universal service”, for enhancing the usability of complementary technologies, for establishing technical compatibility standards and for assuring privacy and security will have major impacts on the outcomes. Three configurations of suppliers—Insurgents, Incumbents and Virtual Community service providers—as well as key user groups are identified. The interactions amoung these groups and the content of private and regulatory decisions provide a foundation for several possible scenarios of future developments. Major differences in the opportunities for European producers and consumers exist depending on which of these scenarios is realised and the role of policy decisions in shaping the outcome.     

通信企业的社会渠道管理浅析

分析了社会渠道对于移动通信企业客户发展、客户服务、品牌宣传、信息流转等方面的重要价值及存在的问题,阐述了社会渠道与自有渠道的关系,提出了一种星状分布的渠道布局方式,并结合黑龙江移动公司在哈尔滨的社会渠道现状,从社会渠道酬金政策的制定入手,探讨了采用"社会渠道酬金管理"闭合环路管理的思路,指出对社会渠道应切实建立一种科学的管理体系,以迎接竞争带来的挑战.     

Optical communication as a social infrastructure of change - [Series editorial]

We believe the broadband evolution is contributing to the improvement of social concerns such as effective production, environmental issues, our aging population, safer society, and so on. This issue features five articles that examine optical communication as a social infrastructure of change.     

NGI之路:IPv6-CJ试验网组播桥实验与分析

描述了IPv6-CJ试验网存在的IPv6组播互操作问题,详细描述了在IPv6-CJ试验网上进行的IPv6组播互操作实验,以及如何建立IPv4/IPv6组播桥和配置IPv6路由器,以解决不同厂商路由器之间的IPv6组播通信问题,并对实验中遇到的问题和解决方法进行了分析.通过一台FreeBSD主机建立的组播桥解决了不同品牌IPv6路由器之间的组播互操作问题,使得位于北京的日立路由器、位于上海的富士通路由器和位于广州的NEC路由器之间可以通畅地进行IPv6组播通信.鉴于NGI网络很可能由多个品牌的IPv6路由器共同组成,因此本实验所获得的经验对NGI环境下的IPv6组播通信有着重要的参考意义.同时展示了三种IPv6路由器的不同命令风格和配置界面.     

Exploring social and psychological factors that influence the gathering of political information online

Qualitative analysis of college students who searched online during the 2008 US presidential election contributes to three research areas: uses and gratifications, media credibility, and selective exposure. The findings identified new social factors that trigger motivations and psychological factors that affect patterns of media use for political information gathering. Word-of-mouth communication from strong, weak, and nonexistent social ties triggered social utility and information seeking motivations. Offline media contributed to online information seeking. Moderate credibility perceptions of media and weak party loyalty limited ideological selective exposure. Results add to research that links social and psychological factors to motivations and media use.     

Disrupting the humanities and social science binary: framing communication studies as a transformative discipline

ABSTRACT

Debates whether communication studies should be housed with the humanities or social sciences have raged on for decades. In response to attacks on the humanities, we argue that the discipline has much to gain from seeing how the humanities contributes to the social sciences and the potential benefits of integrating humanistic and social scientific approaches. Specifically, we present two case studies that illuminate ways humanities-informed thinking has contributed to and benefited social science theory, method, and data. First, we review Jeffrey A. Bennett's Banning Queer Blood to illustrate the importance of reflexivity and practice when analyzing interview data. Then, we highlight how the philosophy of Mikhail Bakhtin influenced Leslie A. Baxter's most recent articulation of relational dialectics theory and development of contrapuntal analysis. Finally, we discuss obstacles and opportunities for engaging in transformative research.     

Drivers of social media fatigue: A systematic review

With a large amount of time spent on social media platforms, more and more people are suffering from social media fatigue. The concept of social media fatigue refers to a host of negative emotional responses to activities on social networking sites, such as tiredness, burnout, exhaustion, frustration, disinterest toward communication. Since research on social media fatigue is still nascent, the goal of this paper is to provide an empirical landscape of this field through a systematic literature review. A systematic literature search and screening process were considered and a final sample of 40 articles were included. First, this review presents the research contexts of the included studies such as geographical location, sample characteristics, data collection method, and the like. Second, it identifies drivers of social media fatigue and categorizes them into three conceptual levels: individual, relational, and environmental. Results of this systematic review outline several key directions for future research. Also, it contributes to a more nuanced theoretical understanding of how social media fatigue arises. Finally, identifying factors influencing fatigue helps social media service providers and health professionals to propose relevant intervention strategies to mitigate this phenomenon.     

融入用户合作与领导激励的社交网络知识传播模型

近年,社交网络已经成为用户普遍使用的进行知识分享的媒介。对社交网络环境中的知识传播进行建模研究,以期为有关部门有效实施监管、提升用户的知识交流效率提供借鉴。以经典的SIS和SIR模型为基础,融入用户合作和领导激励等因子进行优化,并结合复制动态方程构建两种社交网络用户知识传播模型（SISL/SIRL）并进行分析,最后给出数值与模型算例。结果表明：存在领导者的社交网络知识传播速率更快。在社交网络知识传播过程中,易感染用户数量减少,免疫用户数量增加,感染用户数量小范围内上下波动。构建的知识传播模型相对于经典模型与真实社交网络具有更强的拟合性。     

The communication characteristics of virtual teams: a case study

Organizations are encountering novel external environments requiring flexible structures. A number of organizations have used virtual teams to provide the customer responsiveness, human resource flexibility, and speed in project completion these environments demand. Virtual teams create significant communication challenges for its leaders and members. This research analyzed the communication technologies that the Customer Support Virtual Team (CST) of International Consulting Systems (ICS), the pseudonym for a Fortune 500 organization, uses to support team interaction, the degree to which ICS systems and culture supported CST, and finally, the CST members' mindset toward communication and the methods its leader used to create the trust required for effective team interaction. Interviews revealed that ICS mission, strategy, tasks, reward systems, and attitudes toward technology supported virtual team structure. CST members were provided a suite of robust technologies to facilitate interaction; however, they relied heavily on voice mail and a large number of team, project, and organizational databases supported by Lotus Notes to generate a common language that facilitated task completion