Mobile IPv6 and the future of wireless Internet access

Wireless technology is increasingly being used for Internet access and other IP-based communications. To make it easier for wireless users to exploit this trend, the Internet Engineering Task Force (IETF) designed Mobile IP version 4 in 1996. However, MIPv4 has not been deployed widely enough to provide much mobility and has several major shortcomings, including a cumbersome communications process and a limited number of IP addresses. The latter is a key problem because the number of mobile devices that need their own IP address to access the Internet is increasing rapidly. To overcome these deficiencies and introduce new capabilities, the IETF has been developing MIPv6. MIPv6 makes many more IP addresses available and lets mobile users stay connected to the Internet as they move between networks. The paper discusses MIPv6 implementation.     

High level MANET protocol: Enhancing the communication support for mobile collaborative work

Mobile collaborative activities involve on-demand interactions among nomad users. Unavailability of communication support in the physical scenario where users are located cannot be a limitation to carry out such collaboration instances. Mobile workers can take advantage of the communication capability embedded in their mobile devices in order to create communication channels between them. The Mobile Ad-hoc Networks (MANET) are infrastructures that can be used to support the nomad users' activities. However, these networks have a short communication threshold; therefore, they need to include a routing protocol as part of its infrastructure to allow mobile workers to collaborate when they are not physically close. This paper presents an application level routing protocol that was designed to support nomad workers performing mobile collaborative activities. The protocol, named High Level MANET Protocol (HLMP), provides several automatic services that are required by mobile collaborative systems. Some of these services are the automatic MANET formation, peer detection and messages routing. HLMP has been implemented in a mobile communication infrastructure and used in several mobile groupware systems.     

Directional bias in scrolling tasks: a study of users' scrolling behaviour using a mobile text-entry strategy

Mobile devices with limited interaction controls often employ cyclic scrolling for retrieval tasks. In this paper the scrolling behaviour of users entering text using a tree-key input technique based on two-phase cyclic character scrolling is studied. The results show that users have a tendency to scroll more from left-to-right than from right-to-left. However, users do also use the right-to-left functionality to both speed up their text entry task by choosing the shortest path and to make navigational corrections, suggesting that it is appropriate to provide bidirectional scrolling functionality in user interfaces on constrained mobile devices. In situations where a device architect is constrained to providing only unidirectional scrolling, the results suggest that a right-directional design is preferred over a left-directional design.     

Higher impulsivity after exposure to the internet for individuals with high but not low levels of self-reported problematic internet behaviours

The current study explored the impact of internet exposure on the impulsivity of individuals who reported higher or lower levels of problematic internet behaviours. Levels of problematic internet use in 60 individuals were measured using the Internet Addiction Test. Participants were exposed to a choice assessment, in which they could choose between a small immediately-delivered outcome (impulsive), a medium-sized outcome with a medium delay (optimal), and a larger longer-delayed outcome (self-controlled). They were given 15 min access to the internet, and finally were presented with the choice test again. Of the sample, 28% (17/60) had internet-problems, with no difference being found between male and female rates of problematic internet use. Those reporting higher levels of internet-problems displayed no greater impulsive behaviours, prior to internet exposure, than those reporting fewer problems. After internet exposure, higher-problem users displayed greater impulsivity, reflected by a move from self-controlled to impulsive choices. These findings suggest that individuals reporting internet-related problems become more impulsive after exposure to the internet.     

Have a look around: the effect of physical environments on risk behaviour in work-related versus non-work related decision-making tasks

Abstract

Due to ubiquitous computing, knowledge workers do not only work in typical work-associated environments (e.g. the office) but also wherever it best suits their schedule or preferences (e.g. the park). In two experiments using laboratory and field methods, we compared decision making in work and non-work environments. We hypothesised that participants make riskier work-related decisions when in work-associated environments and riskier non-work-related decisions in non-work-associated environments. Therefore, if environment (work vs. non-work) and decision-making task (work-related vs. non-work-related) are incongruent, then risk-taking should be lower, as the decision maker might feel the situation is unusual or inappropriate. Although results do not reveal that work-associated environments generally encourage riskier work-related decisions (and likewise for non-work), we found environmental effects on decision making when including mood as a moderator.

Practitioner summary: Mobile workers are required to make decisions in various environments. We assumed that decisions are more risky when they are made in a fitting environment (e.g. work-related decisions in work environments). Results of the two experiments (laboratory and field) only show an environmental effect when mood is included as a moderator.     

Exploiting mobility patterns for inter-technology handover in mobile environments

Mobile terminals with multi-radio devices have become increasingly prevalent. This makes it possible for Internet applications to be supported by heterogeneous wireless networks while the terminal is on the move. As the user is constantly moving, it is highly desirable that the terminal connects to the best network and retains high performance of network connections. Handovers can be made within the same type of network (horizontal handover) or different types of networks (vertical handover). This paper focuses on link-layer inter-technology vertical handovers. Vertical handovers present several great challenges, such as user mobility randomness, high handover overhead and optimality requirement. Existing work often focuses only on the current network condition when making handover decisions, ignoring future performance of the terminal. As a result, a handover decision good for the current moment may soon become poor when the user moves to another place. This paper is motivated by the observation that users in a given mobile environment, such as university or enterprise campus, exhibit clear mobility patterns. We propose an approach for making handover decisions, which explicitly exploits user mobility patterns. This approach can produce high-performance handover decisions in the long run. Employing a comprehensive framework for preference customization, the approach supports user customization caring for different user preferences. Extensive real trace driven simulations and comparative study show our algorithm is better than the conventional vertical handover algorithms.     

Mobile text-entry and visual demands: reusing and optimizing current solutions

Mobile devices are increasingly used for text-entry in contexts where visual attention is fragmented and graphical information is inadequate, yet the current solutions to typing on virtual keyboards make it a visually demanding task. This work looks at assistive technologies and interface attributes as tools to ease the task. Two within-subject experiments were performed with 23 and 17 participants, respectively. The first experiment aimed to understand how walking affected text-entry performance and additionally to assess how effective assistive technologies can be in mobile contexts. In the second experiment, adaptive keyboards featuring character prediction and pre-attentive attributes to ease visual demands of text-entry interfaces were developed and evaluated. It has been found that both text-input speed and overall quality are affected in mobile situations. Contrary to the expectations, assistive technologies proved ineffective with visual feedback. The second experiment showed that pre-attentive attributes do not affect users’ performance in task-entry tasks, even though a 3.3–4.3 % decrease in error rates was measured. It was found that users reduce walking speed to compensate for challenges placed by mobile text-entry. Caution should be exercised when transferring assistive technologies to mobile contexts, since they need adaptations to address mobile users’ needs. Also, while pre-attentive attributes seemingly have no effect on experienced QWERTY typists’ performance, they showed promise for both novice users and typists in attention-demanding contexts.     

Time,place, technology: Twitter as an information source in the Wisconsin labor protests

Recently, Twitter has become a prominent part of social protest movement communication. This study examines Twitter as a new kind of citizen journalism platform emerging at the aggregate in the context of such “crisis” situations by undertaking a case study of the use of Twitter in the 2011 Wisconsin labor protests. A corpus of more than 775,000 tweets tagged with #wiunion during the first 3 weeks of the protests provides the source of the analyses. Findings suggest that significant differences exist between users who tweet via mobile devices, and thus may be present at protests, and those who tweet from computers. Mobile users post fewer URLs overall; however, when they do, they are more likely to link to traditional news sources and to provide additional hashtags for context. Over time, all link-posting declines, as users become better able to convey first-hand information. Notably, results for most analyses significantly change when restricted to original tweets only, rather than including retweets.     

Mobile agents in wireless devices

The networks that connect handheld wireless devices such as cell phones and PDAs suffer from low bandwidth and a high incidence of network errors. By employing mobile agents, such devices could provide a reliable technology for message transport over wireless links. Mobile agents are inherently distributed software entities that reduce the load on the network when they move. Mobile agents can be employed in wireless handheld devices in two ways: An agent platform could be installed on the device, enabling mobile agents to run directly on it, or devices could access and use remote mobile agents running on wired networks. Each approach is viable and has its own advantages and domain-specific applications. Some high-end devices would benefit from running a mobile agent platform that lets agents run locally, but this would not be beneficial to others because of processing power and memory constraints or for security reasons.     

An overview of vertical handover techniques: Algorithms, protocols and tools

Wireless technologies, under the “Anywhere, Anytime” paradigm, offer users the promise of being always attached to the network. Mobile devices enabled with multiple wireless technologies make possible to maintain seamless connectivity in highly dynamic scenarios such as vehicular networks (VNs), switching from one wireless network to another by using vertical handover techniques (VHO). In this paper we present an overview of VHO techniques, along with the main algorithms, protocols and tools proposed in the literature. In addition we suggest the most appropriate VHO techniques to efficiently communicate in VN environments considering the particular characteristics of this type of networks.     

Supporting routine decision-making with a next-generation alarm clock

People make hundreds of decisions every day. Rather than optimize those decisions by gathering pertinent information, people instead rely on routines. While those routines are usually sufficient, they do occasionally fail. Those failures present an opportunity to improve decision-making by providing low-cost information when and where people start to follow their routines. We conducted a study to examine the routines that users follow at night and in the morning. Drawing on the results, we created a next-generation alarm clock that highlights unusual situations to help users determine when and how to modify their routines to more effectively decide on an alarm time, what to wear, when to get out of bed, and when to leave for work.     

Is compulsive internet use related to sensitivity to reward and punishment,and impulsivity?

Aim of the present study was to examine whether the personality correlates sensitivity to reward and to punishment, and impulsivity predict compulsive internet use (CIU). Furthermore, the predictive value of these personality correlates was compared to the predictive value of factors relating to psychosocial wellbeing. The results showed that particularly rash spontaneous impulsivity predicts CIU and that this personality factor is more important than psychosocial wellbeing factors. Sensitivity to reward, which is supposed to play a role in craving processes associated with substance abuse and eating disorders, could not be related to CIU. The data suggest that internet users who are characterized by an impulsive personality feature, are less able to control their use of the internet, which makes them more vulnerable to develop CIU.     

Mobile Web services: a new agent-based framework

Mobile devices and server applications often run on different platforms, which can make integration problematic. Web services might offer a solution, but they typically include XML protocols that are too "heavy" for mobile devices. In this article, we describe agent-based mobile services framework. It uses wireless portal networks and eliminates XML processing on mobile clients. It also offers dynamic service selection and rapid application development and deployment for Web service providers.     

无线PKI中具有安全代理的新型CA方案

无线PKI是WAP Forum提出的用于保护无线通信安全的协议。通过使用WPKI，手持设备客户端能够利用公开密钥技术来保护数据的保密性和完整性。由于手持设备存储容量和计算速度都相当受限，只有少量的手持设备能流畅的完成WPKI所必须的计算任务。即使采用了具有强计算能力的手持设备，用户也仅能与采用了WPKI技术的部分服务器进行安全通信。手持设备用户仍然无法和Internet上的任意用户之间建立可靠的连接。通过对现有的无线PKI系统进行分析，提出了无线PKI的一种可选的运行方式。新的运行方式将客户端难以承担的计算任务移植到可信安全代理服务器端，并采用密码协议保证安全代理的正确运行。新协议降低了WPKI框架对无线手持设备的计算和存储能力的要求，同时系统的安全性也得到了进一步的保障。而无线手持设备用户也能够和Internet上的用户进行安全的通信。     

Everyday use of computer-mediated communication tools and its evolution over time: An ethnographical study with older people

Based on a 3-year ethnographical study, this paper discusses the prolonged use of computer-mediated communication (CMC) tools by approximately 400 older people in an adult education centre in Barcelona (Spain). Contrary to oversimplified views of older people as ICT users, this paper shows that they make a very rich use of CMC tools. Relevant elements of this use are their permanent desire to feel and be included, social, independent and competent ICT users. Despite the numerous interaction issues they face when using ICT, some are constant across different tools. Difficulties due to cognition limit their interactions more severely than those problems due to perceiving visual information or using the mouse. By examining the longitudinal aspect of the study, this paper addresses the evolution of technology use and whether the interaction issues that most of the current older people exhibit will be relevant when today’s more ICT literate young adults grow older. Interaction issues due to cognition are time-persistent, and independent of both experience and practice with ICT. Difficulties reading from the screen or using input devices are overcome with ICT experience. The strategies adopted by older people for coping with all these interaction issues are always targeted at feeling and being included, social, independent and competent ICT users. The results deepen current understanding of tools use in connecting older people with their social circles and the interaction issues most of them encounter when using ICT. The results also suggest that cognitive-related problems will be the most important ones in our work with the next generation of older people.     

一种基于混合社区的移动机会网络数据传输机制

由人携带或使用智能设备组成的移动机会网络采用"存储-携带-转发"的通信机制,通过中继转发来实现节点之间的数据传递。为了改善网络性能,往往需要借助节点的社会属性来进行中继选择和制定转发策略。然而,在已有的传输机制中,往往只是利用节点的部分社会属性,不能完全反映出节点之间的社会关系。为此,提出了一种新的基于混合社区的数据传输机制,并给出了混合社区的内涵、混合社区的构建方法和基于混合社区的数据传输算法。基于几种真实轨迹数据集的实验结果表明,与已有的几种经典路由算法相比,该方法传输成功率较高,传输延迟较短,性能更好。     

Powerful change part 1: batteries and possible alternatives for the mobile market

Mobile phone companies sell more batteries than phones to consumers. The devices users buy generally include rechargeable batteries so that they are immediately useful. Companies try to protect their batteries with various design and utility patents to keep third-party vendors from competing too heavily with their after-market sales. This protection is necessary because battery technology changes slowly-consumers receive little incentive to upgrade their batteries unless they fail or the consumer desires a larger one. Power is a difficult issue and is often overlooked in mobile computers. However, innovative opportunities abound for exploring this problem. We introduce the issue and propose some alternatives to batteries. In subsequent issues we'll address methods of being more power efficient by using resources both on the body and in the environment.     

半监督自训练的方面提取

方面提取是观点挖掘和情感分析任务中的关键一步,随着社交网络的发展,用户越来越倾向于根据评论信息来帮助进行决策,并且用户也更加关注评论的细粒度的信息,因此,从海量的网络评论数据中快速挖掘方面信息对于用户快速决策具有重要意义。大部分基于主题模型和聚类的方法在方面提取的一致性上效果并不好,传统的监督学习的方法效果虽然表现很好,但是需要大量的标注文本作为训练数据,标注文本需要消耗大量的人力成本。基于以上问题,本文提出一种基于半监督自训练的方面提取方法,充分利用现存的大量未标签的数据价值,在未标签数据集上通过词向量模型寻找方面种子词的相似词,对每个方面建立与数据集最相关的方面表示词集合,本文方法避免了大量的文本标注,充分利用未标签数据的价值,并且本文方法在中文和英文数据集上都表现出了理想的效果。     

移动互联网:终端、网络与服务

随着宽带无线接入技术和移动终端技术的飞速发展,人们迫切希望能够随时随地乃至在移动过程中都能方便地从互联网获取信息和服务,移动互联网应运而生并迅猛发展.然而,移动互联网在移动终端、接入网络、应用服务、安全与隐私保护等方面还面临着一系列的挑战.其基础理论与关键技术的研究,对于国家信息产业整体发展具有重要的现实意义.文中从移...