This thesis examines the experiences of women becoming Internet users and readers of online texts. Millions of women in the UK began to access websites and exchange emails for the first time in the late 1990s and beginning of the 215' century. The existence of a gender gap amongst earlier adopters revealed that there must be particular obstacles facing women as new users and readers, which the thesis sets out to investigate using a multi-disciplinary approach and a range of research methods. The data is drawn from three distinct sources. First, sixteen female and six male readers were observed and interviewed while accessing their own choice of websites. This produced data on texts-in-use in conjunction with audiotaped literacy events, taking the method pioneered in schools by the Fact and Fiction Project, in its study of gender and literacy, in a new direction. Secondly, data on adult women learning to use the Internet was gathered in the form of a reflexive account of teaching beginners' classes between 2000 and 2002 at an inner-London public access location. Thirdly, women's reactions to one specific online text, an emailed petition about women in Afghanistan, were explored through an analysis of emails and comments made in interviews. The analysis situates reading online as a socially constructed literacy practice while stressing the distinctiveness of individual literacy events. It is argued that some events have particular significance, impeding or assisting the process of developing a repertoire of new literacy practices. The obstacles women face are identified as linked to the dominance of particular online texts, gendered power relations in the home and workplace, and previous educational experiences. Opportunities to create as well as read, and feeling sufficiently in control of work, access and technology, are identified as key factors in becoming a confident online reader

published_or_final_version / Sociology / Doctoral / Doctor of Philosophy

Anonymous credential is an important tool to protect the identity of users in the Internet for various reasons (e.g. free open speech) even when a service provider (SP) requires user authentication. Yet, misbehaving users may use anonymity for malicious purposes and SP would have no way to refrain these users from creating further damages. Revocable anonymous credential allows SP to revoke a particular anonymous user based on the observed behavior of a session the user conducted. However, such kind of all-or-nothing revocation does not work well with the “Web 2.0” applications because it does not give a user a second chance to remedy a misconduct, nor rewards for positive behaviors. Reputation support is vital for these platforms. In this thesis, we propose two schemes with different strengths that solve this privacy and reputation dilemma. Our first scheme, PE(AR)2, aims to empower anonymous credential based authentication with revocation and rewarding support. The scheme is efficient, outperforms PEREA which was the most efficient solution to this problem, with an authentication time complexity O(1) as compared with other related works that has dependency on either the user side storage or the blacklist size. PEREA has a few drawbacks that make it vulnerable and not practical enough. Our scheme fixes PEREA's vulnerability together with efficiency improvement. Our benchmark on PE(AR)2 shows that an SP can handle over 160 requests/second when the credentials store 1000 single-use tickets, which outperforms PEREA with a 460 fold efficiency improvement. Our second scheme, SAC, aims to provide a revocation and full reputation support over anonymous credential based authentication system. With a small efficiency trade-o_ as compared with PE(AR)2, the scheme now supports both positive and negative scores. The scoring mechanism is now much more flexible, that SP could modify the rated score of any active sessions, or declare that no more rating should be given to it and mark it as finalized. SAC provides a much more elastic user side credential storage, there is no practical limit on the number of authentication sessions associated with a credential. Unlike other schemes, SAC make use of a combined membership proof instead of multiple non-membership proofs to distinguish if a session is active, finalized, or blacklisted. This special consideration has contributed to the reduction of efficiency-flexibility trade-off from PE(AR)2, making the scheme stay practical in terms of authentication time. Our benchmark on SAC shows that an SP can handle over 2.9 requests/second when the credentials store 10000 active sessions, which outperforms BLACR-Express (a related work based on pairing cryptography with full reputation support) with a 131 fold efficiency improvement. Then we analyze the potential difficulties for adopting the solutions to any existing web applications. We present a plugin based approach such that our solutions could run on a user web browser directly, and how a service provider could instruct the plugin to communicate using our protocol in HTML context. We conclude our thesis stating the solutions are practical, efficient and easy to integrate in real world scenario, and discuss potential future works. / published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy

Department of Biochemistry in HKU has been planning to implement virtual lab blended learning solution into their experiment related courses. Based on selected case, the study investigated whether the virtual lab would arouse more learning interests and improve the learning gains for students. Also, the study concluded some useful suggestions for virtual lab blended learning and generalized a few guidelines for instructional design on virtual lab. The study adopted mixed research methods with combination of quantitative and qualitative studies. With the ADDIE instructional design model, the researcher and his advisor constructed initial virtual lab in Second Life virtual design platform for selected class based on the teacher’s suggestions and course arrangements. Then chosen students participated in demonstration classes organized in two groups, one with Second Life virtual lab for teaching and learning (SL Group) while the other without(Non-SL Group). The students were given same quiz in the Moodle LMS to compare their basic academic learning outcomes. Meanwhile, researcher with other three observers recorded students’ class performances for each learning tasks by camera and observation forms. At the end of the class, surveys were delivered to them to collect their perceptions about learning with Second Life virtual lab and their suggestions for virtual lab design. The research findings indicate that students can basically accept the virtual lab blended learning solution. Compared with Non-SL Group, students from SL Group achieved higher average scores in academic quiz with more passions in class learning. They were more active in joining class activities and discussions in small team with more interactions between team members. However, they were also troubled by the use of virtual lab because of unclear instruction, technical problems, virtual learning activities design and virtual lab system issues. The paper argued the way of integrating the virtual lab into experiment courses in biochemistry teaching and learning. It discussed the proper ways to design the blended virtual lab learning system for learning purpose and questioned the virtual technologies used for learning design. Finally, it concluded some principles and guideline framework for blended virtual lab design and development in biochemistry teaching and learning, which can be also applied for similar design and development in health and medical education. / published_or_final_version / Education / Master / Master of Science in Information Technology in Education

The Internet is dynamically shared by numerous flows of data traffic. Network congestion occurs when the aggregate flow rate persistently exceeds the network capacity, leading to excessive delivery delay and loss of user data. To control network congestion, a flow needs to adapt the sending rate to its inferred level of congestion, and a packet switch needs to report its local level of congestion. In this framework of Internet congestion control, it is important for flows to react promptly against congestion, and robustly against interfering network events resembling congestion. This is challenging due to the highly dynamic interactions of various network components over a global scale. Prior approaches rely predominantly on empirical observations in experiments for constructing and validating designs. However, without a careful, systematic examination of all viable options, more efficient designs may be overlooked. Moreover, experimental results have limited applicability to scenarios beyond the specific experimental settings. In this thesis, I employ a novel, systematic design approach. I formalize the design process of Internet congestion control from a minimal set of empirical observations. I prove the robustness and optimality of the attained design in general settings, and validate these properties in practical experimental settings. First, I develop a systematic method for enhancing the robustness of flows against interfering events resembling congestion. The class of additive-increase-multiplicative-decrease (AIMD) algorithms in Transmission Control Protocol (TCP) is the set of dominant algorithms governing the flow rate adaptation process. Over the present Internet, packet reordering and non-congestive loss occur frequently and are misinterpreted by TCP AIMD as packet loss due to congestion. This leads to underutilization of network resources. With a complete, formal characterization of the design space of TCP AIMD, I formulate designing wireless TCP AIMD as an optimal control problem over this space. The derived optimal algorithm attains a significant performance improvement over existing enhancements in packet-level simulation. Second, I propose a novel design principle, known as pricing-link-by-time (PLT), that specifies how to set the measure of congestion, or “link price”, at a router to provide prompt feedback to flows. Existing feedback mechanisms require sophisticated parameter tuning, and experience drastic performance degradation with improperly tuned parameters. PLT makes parameter tuning a simple, optional process. It increases the link price as the backlog stays above a threshold value, and resets the price once the backlog goes below the threshold. I prove that such a system exhibits cyclic behavior that is robust against changes in network environment and protocol parameters. Moreover, changing the threshold value can control delay without undermining system performance. I validate these analytical results using packet-level simulation. The incremental deployment of various enhancements have made Internet congestion control highly heterogeneous. The final part of the thesis studies this issue by analyzing the competition among flows with heterogeneous robustness against interfering network events. While rigorous theories have been a major vehicle for understanding system designs, the thesis involves them directly in the design process. This systematic design approach can fully exploit the structural characteristics, and lead to generally applicable, effective solutions. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Background: Despite its exclusion in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, Internet addiction disorder (IAD) has received attention especially from the psychiatric community. Associated with multiple factors, IAD among adolescents may cause physical, emotional, social, and function impairments that extend to adulthood. Objective: This systematic review explores the prevalence of IAD among adolescents and identifies associated factors. Methods: The databases of Medline and PubMed were searched for related literature through the Boolean Advanced Search using the keywords “Internet” or “cyber,” “addiction” or “dependence,” and “adolescent” or “youth” from 2003 to 2013. A total of 232 articles were retrieved and screened. Only 11 cross-sectional studies from 5 countries were included in this systematic review. The age of adolescent participants in these studies ranged from 13.8 to 17.3 years. Four assessments were employed to explore IAD among adolescents in the 11 reviewed studies. Among these studies, 4 employed the Young’s Internet Addiction (IA) Test, 4 utilized the Chen IA Scale, 2 studies used the Internet-Related Addiction Scale, and one study adhered to the Young’s DRM 52 Scale of Internet use among adolescents. Results: The prevalence of IAD among adolescents range from 1.5% to 18.8%. In this review, factors associated with high prevalence of IAD among adolescents include psychological (e.g., depression, attention deficiency, and hyperactivity disorder), social (e.g., family conflict),and demographic factors (e.g., male gender and older age), as well as use of the Internet (e.g., longer use of the Internet, online chatting, and gaming). Conclusions: With the increasing use of the Internet in managing daily activities, including learning, communication, and entertainment, it has become an essential part of human living in the modern world. The negative effects of IAD among adolescents might result in high healthcare cost, particularly in psychiatric treatment and rehabilitation. Thus, prevention of IAD at the early stage and promotion of healthy use of the Internet are important in safeguarding the mental wellness of people. The result of this review showed the prevalence of IAD among adolescents is associated with psychological, socio-demographic, environmental and living factors. Primary preventive education that focuses on the healthy use of the Internet and guidance could be promoted among adolescents and parents at the school and community levels, respectively. Moreover, secondary prevention programs that concentrate on the early prevention and identification of IAD and specifically designed for the at-risk group could be launched. Extra resources for the employment of counseling personnel should be considered. Future research on the at-risk group population of IAD among adolescents could be conducted. These initiatives could assist in designing a tailor-made intervention, and eventually in preventing the early onset of IAD. / published_or_final_version / Public Health / Master / Master of Public Health

Das Ziel dieser Arbeit ist es, aktuelle Entwicklungen im Online Insuring bei den österreichischen Lebensversicherern im Privatkundensegment zu erfassen und im Anschluss daran strategische Implikationen abzuleiten, die dem Versicherer einen Hinweis darauf geben kann, welche Aspekte besonders wichtig bei der Umsetzung des Online Insuring sind. (Autorenref.) / Series: Arbeitspapiere zum Tätigkeitsfeld Risikomanagement und Versicherung / Institut für Versicherungswirtschaft

Not available / text

Not available / text

Not available / text