Guest Editors' Introduction: Social Networks and Social Networking

This issue's theme includes three articles on research activities that have drawn on ideas from social networking to drive innovative designs. The focus covers the design, development, and study of social technologies at the level of individuals, groups, and organizations. Although the tools described here are all intended for individuals, each article highlights how new technologies and technical competencies will further push our understanding of human social-networking drives and desires.     

Public Discourse, Community Concerns, and Civic Engagement: Exploring Black Social Networking Traditions on BlackPlanet.com

This study explores community life on a black social network site, BlackPlanet, to see whether and how participants engage in public discussions; if these discussions center on issues considered to be critical to the black community; and if so, the extent to which participants' online networks are used to foster some level of civic engagement. Participation analysis, content analysis, and a thematic analysis were used to analyze public discussions on the site's community forums. The findings show that participants are deeply committed to ongoing discussions about black community issues. However, none of these discussions moved beyond a discursive level of civic engagement, suggesting that the potential for mobilization through social networking online has not yet been realized, despite the traditional orientation to community service among blacks in America.     

On Social Networking and Communication Paradigms

Many will agree that email is badly broken when it comes to protecting users from spam, especially spoofing. With the growing prevalence of social networking sites, the increasing visibility into end users’ social connections will make it easy for scammers to figure out how to better forge return addresses, among other problems. Those who create social networking infrastructures must be vigilant in defending such sites, to keep spam issues from becoming as prevalent there as they now are with email.     

Cultural Entrepreneurship: The Impact of Social Networking on Success

Because of the complex structures characteristic of the arts sector and creative industries, it is often thought that external network ties of leading managers are critical to the success of their cultural enterprises. Based on research into entrepreneurship and promoters' activity, this study examines the influence of social network relationships on the success of cultural establishments in Germany. The regression analysis of data from 121 private arts and culture ventures presented here clearly shows that founders as well as managers can overcome numerous barriers through their engagement and activity in social networks, and thereby exercise to a significant degree a positive influence on establishing their enterprise. As expected, this effect is even stronger in cases of low sponsorship of cultural activities on the part of cities and communities. Contrary to expectations, the positive effect of intensive networking activities is not increased by a high intensity of competition; it is worth noting that the effect is strongest in situations of low competitive pressure. The results of this study demonstrate that successful networking expertise, as postulated by research into promoters' activity, is of great importance for overcoming significant barriers in the cultural sector, but that its effectiveness also has limits.     

Datenschutzkonformes Social Networking: Clique und Scramble!

Soziale Netzwerke sind aus dem Web 2.0 heute kaum mehr wegzudenken und werden von einer stetig steigenden Zahl von Usern genutzt, vor allem Jugendliche sind mehrmals in der Woche in diesen aktiv.Das Ph?nomen des Social Networking stellt den Datenschützer dabei vor ein grunds?tzliches Problem: User nutzen SNS, weil sie (personenbezogene) Daten mit anderen austauschen wollen. Dies stellt zwar keinen unmittelbaren Widerspruch zu den Grundprinzipien des Datenschutzes dar, macht es aber doch zumindest schwieriger, ein datenschutzkonformes Social Networking zu erm?glichen.     

ShadowEth: Private Smart Contract on Public Blockchain

Blockchain is becoming popular as a distributed and reliable ledger which allows distrustful parties to transact safely without trusting third parties. Emerging blockchain systems like Ethereum support smart contracts where miners can run arbitrary user-defined programs. However, one of the biggest concerns about the blockchain and the smart contract is privacy, since all the transactions on the chain are exposed to the public. In this paper, we present ShadowEth, a system that leverages hardware enclave to ensure the confidentiality of smart contracts while keeping the integrity and availability based on existing public blockchains like Ethereum. ShadowEth establishes a confidential and secure platform protected by trusted execution environment (TEE) off the public blockchain for the execution and storage of private contracts. It only puts the process of verification on the blockchain. We provide a design of our system including a protocol of the cryptographic communication and verification and show the applicability and feasibility of ShadowEth by various case studies. We implement a prototype using the Intel SGX on the Ethereum network and analyze the security and availability of the system.     

基于WiFi技术的擦身社交平台研究

文章描述了一种在Wi Fi环境下的基于UPD通讯技术的局域网自动交友平台技术,主要用于有WIFI网络环境下、不需要接入Internet的、实时互动的手持设备上。用户只需要保持移动设备处于开启状态,便可随时自动去进行信息的交互。     

向量等分量数的两方保密计算及推广应用

安全多方计算是近年来国际密码学界的研究热点.安全向量计算作为安全多方计算研究的重要内容,也是解决许多实际安全计算问题的基本工具.在科学研究中很多研究对象都可以用向量来刻画,并通过对这些向量进行各种计算从而得到所需结果,这也使安全向量计算在电子商务推荐、保密的分类、保密聚类等研究中得到了广泛应用.本文主要研究向量等分量数计算问题,即保密计算两个向量有多少个对应分量相等,这个问题的研究对于安全多方计算和隐私保护有重要的理论与实际意义.首先设计编码方法对保密向量进行编码,并结合具有加法同态性的Paillier加密方案,针对数据范围有限制和无限制两种不同情形分别设计了高效的保密计算协议,应用模拟范例严格证明了协议的安全性.作为向量等分量数保密计算协议的应用,进一步研究了向量等分量数阈值判定问题和向量优势统计问题的解决方案.并以所设计的协议为基础解决了多个点与区间(或集合)关系判定问题和字符串模式匹配等实际应用问题.复杂性分析和实验测试都表明本文协议是高效和实用的.     

网络化社会媒体的传播及应用

介绍社会媒体的网络特性与信息传播特点和社会媒体的传播机制．以及当前主要的研究课题,其中包括社会媒体的传播方法与模型、传播影响力、主题模型发现和情感倾向性分析等,简单介绍社会媒体信息传播在虚拟社会管理和社会媒体服务中的应用前景。     

基于内容的移动社交网络审计分析引擎

随着移动互联网的飞速发展以及社会化网络的出现,微信等移动社交类应用在生活的各个层面为人们带来便利,但同时也带来了谣言、泄密等网络安全问题。传统的基于字符串匹配的关键词过滤审计引擎已经不能满足人们的需求。针对传统特征项权重算法在处理变异短文本方面的不足,提出了改进的TF-IDF算法,同时将社会网络计算的相关技术应用到审计引擎中,实现了基于内容的事件抽取和表达。实验结果表明,改进后的算法具有较高的准确率和召回率。     

Social Interaction in YouTube Text‐Based Polylogues: A Study of Coherence

Since YouTube was launched, its emblematic video‐sharing facility has attracted considerable attention as a social networking system of cultural production. In addition to vlogging, YouTube offers a text facility through which YouTubers share and negotiate opinions. However, research into the latter is scarce, especially within language‐based disciplines (Androutsopoulos & Beiβwenger 2009; Zelenkauskaite & Herring 2008). This article contributes to addressing this imbalance by focusing on YouTube text‐based ‘conversation’ (Herring 2010a). Specifically, it examines coherence in a corpus of YouTube postings in Spanish. Although coherence has been the object of much academic debate in other forms of computer‐mediated communication, no empirical analysis of coherence in YouTube text has been undertaken to date. Results underline the conversational potential of this facility.     

Social Networking Sites: Their Users and Social Implications — A Longitudinal Study

The rapid adoption of social networking sites (SNSs) raises important questions about the social implications of such usage. Drawing on unique longitudinal data, surveying a representative sample of Norwegian online users (N = 2,000, age 15–75 years) in 3 annual waves (2008, 2009, and 2010), this study found a significantly higher score among SNS users in comparison to nonusers in 3 out of 4 social capital dimensions: face‐to‐face interactions, number of acquaintances, and bridging capital. However, SNS‐users, and in particular males, reported more loneliness than nonusers. Furthermore, cluster analyses identified 5 distinct types of SNS users: Sporadics, Lurkers, Socializers, Debaters, and Advanced. Results indicate that Socializers report higher levels of social capital compared to other user types.     

基于近场通信的移动社交系统

目前的社交系统都是基于互联网才能使用相关服务,在离线状态下功能不足。对比现有系统,利用近场通信（NFC）和无线直连（Wi-Fi Direct）构建一个Android平台的移动社交系统,具有离线社交的功能,提供触碰交互、不用接入互联网也可以P2P聊天和分享文件,同时最大程度保证离线交互的安全性。     

Increasing individuals' involvement and WOM intention on Social Networking Sites: Content matters!

Applying Technology Acceptance Model (TAM) and Elaboration Likelihood Model (ELM), we investigated the effects of content type (utilitarian vs. hedonic) on individuals' involvement and intention to subscribe/promote a company's SNS. An experiment was conducted with 171 participants. We found that utilitarian content worked better for highly involved individuals than hedonic content, but hedonic content increased individuals' situational involvement with a company's SNS more than utilitarian content among low-involved people. Both situational and enduring involvements influenced intention to subscribe to and continuously promote the company's SNS. Theoretical and practical implications are discussed further.     

Social Media Advertising through Private Messages and Public Feeds: A Congruency Effect between Communication Channels and Advertising Appeals

This paper investigates the effectiveness of agentic and communal advertising appeals delivered through two IT-enabled communication channels (private messages and public feeds) on social media. Drawing on the prior literature, we propose a congruency effect of advertising appeals and channels on advertisement effectiveness. The results of three experiments show that agentic appeals delivered through public feeds generate favorable advertisement attitudes, and the effect is mediated by consumer self-efficacy perception. Communal appeals delivered through private messages engender positive advertisement attitudes, and the effect is mediated by consumer social self-efficacy perception. The findings provide implications to firms in social media advertising strategies.     

中国社交类应用用户行为研究

"社交类应用"泛指具有社交功能的互联网应用,包括社交网站、微博、即时通信工具、博客、论坛等,本文重点研究社交网站、微博以及即时通信工具。在社交类应用用户特征及重叠情况、社交类应用用户变化以及各社交类应用用户使用行为差异的研究基础上,分析了社交类应用对新闻资讯类网站、网络购物、手机在线游戏等相关产业的影响,并对社交类应用的发展提出了相关建议。     

专网共享公网信息的研究

对于一些涉及有国家机密的机构或部门的专网共享公网的信息,要求严格的做到专网的信息不被破坏和泄露。解决的方案就是研究开发新型的网络结构,使之既能实现专网、公网信息的安全隔离,又能实现实时的数据交换。     

基于公私属性的多授权中心加密方案

基于属性的加密方法可以简化云计算环境中的密钥管理和访问控制问题,是适用于云环境的加密方案。文中提出了一种基于公私属性的多授权中心加密方案。该方案将属性分为公有属性和私有属性,将用户的角色权限信息等作为用户的公有属性,将用户登录密码、设备上的标识码等作为用户的私有属性。利用公有属性实现访问控制,在云服务器上安全地共享数据;利用私有属性实现信息流的安全控制,确保只有特定用户在特定设备上使用数据。提出的方案可以实现密钥追踪和属性撤销,基于私有属性的加密还可以实现抗合谋攻击。