20 research outputs found
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Learning to de-anonymize social networks
Releasing anonymized social network data for analysis has been a popular idea among data providers. Despite evidence to the contrary the belief that anonymization will solve the privacy problem in practice refuses to die. This dissertation contributes to the field of social graph de-anonymization by demonstrating that even automated models can be quite successful in breaching the privacy of such datasets. We propose novel machine-learning based techniques to learn the identities of nodes in social graphs, thereby automating manual, heuristic-based attacks. Our work extends the vast literature of social graph de-anonymization attacks by systematizing them. We present a random-forests based classifier which uses structural node features based on neighborhood degree distribution to predict their similarity. Using these simple and efficient features we design versatile and expressive learning models which can learn the de-anonymization task just from a few examples. Our evaluation establishes their efficacy in transforming de-anonymization to a learning problem. The learning is transferable in that the model can be trained to attack one graph when trained on another. Moving on, we demonstrate the versatility and greater applicability of the proposed model by using it to solve the long-standing problem of benchmarking social graph anonymization schemes. Our framework bridges a fundamental research gap by making cheap, quick and automated analysis of anonymization schemes possible, without even requiring their full description. The benchmark is based on comparison of structural information leakage vs. utility preservation. We study the trade-off of anonymity vs. utility for six popular anonymization schemes including those promising k-anonymity. Our analysis shows that none of the schemes are fit for the purpose. Finally, we present an end-to-end social graph de-anonymization attack which uses the proposed machine learning techniques to recover node mappings across intersecting graphs. Our attack enhances the state of art in graph de-anonymization by demonstrating better performance than all the other attacks including those that use seed knowledge. The attack is seedless and heuristic free, which demonstrates the superiority of machine learning techniques as compared to hand-selected parametric attacks
Factors Influencing Customer Satisfaction towards E-shopping in Malaysia
Online shopping or e-shopping has changed the world of business and quite a few people have
decided to work with these features. What their primary concerns precisely and the responses from
the globalisation are the competency of incorporation while doing their businesses. E-shopping has
also increased substantially in Malaysia in recent years. The rapid increase in the e-commerce
industry in Malaysia has created the demand to emphasize on how to increase customer satisfaction
while operating in the e-retailing environment. It is very important that customers are satisfied with
the website, or else, they would not return. Therefore, a crucial fact to look into is that companies
must ensure that their customers are satisfied with their purchases that are really essential from the ecommerce’s
point of view. With is in mind, this study aimed at investigating customer satisfaction
towards e-shopping in Malaysia. A total of 400 questionnaires were distributed among students
randomly selected from various public and private universities located within Klang valley area.
Total 369 questionnaires were returned, out of which 341 questionnaires were found usable for
further analysis. Finally, SEM was employed to test the hypotheses. This study found that customer
satisfaction towards e-shopping in Malaysia is to a great extent influenced by ease of use, trust,
design of the website, online security and e-service quality. Finally, recommendations and future
study direction is provided.
Keywords: E-shopping, Customer satisfaction, Trust, Online security, E-service quality, Malaysia
Linear Order in Language:an Error-Driven Learning Account
Learners of German often struggle with learning the grammatical gender of nouns and their correct articles, for example, that it should be “die Gabel” (the fork) and not “der Gabel”. Why is this so hard? And why do gender systems even exist?I taught participants differently structured artificial languages and found that it is especially difficult to learn a gender system, when gender is marked before the noun (e.g., in German: “die Gabel”, the fork, vs. “der Löffel”, the spoon) as compared to when gender is marked after the noun (e.g., in Albanian: “pirun-i”, the fork, vs. “lug-a”, the spoon). With computational simulations I could show that this effect arises because human learning is sensitive to the order of words.However, while gendered articles are hard to learn, they can facilitate communication because they can make following nouns more predictable and therefore easier to process: for example, after the German article “der”, “Löffel” is quite likely, “Gabel”, however, is very unlikely to follow. This is a function that gendered suffixes, as in Albanian, or genderless articles, as in English, cannot fulfill. In a language production study, I observed that speakers produce more articles that can make following nouns predictable, such as German articles, than articles that cannot fulfill this function, such as the English article “the”.I conclude that the order in which gender is marked in languages affects language learning as well as communication. This makes German gender hard to learn but useful for communication
AVATAR - Machine Learning Pipeline Evaluation Using Surrogate Model
© 2020, The Author(s). The evaluation of machine learning (ML) pipelines is essential during automatic ML pipeline composition and optimisation. The previous methods such as Bayesian-based and genetic-based optimisation, which are implemented in Auto-Weka, Auto-sklearn and TPOT, evaluate pipelines by executing them. Therefore, the pipeline composition and optimisation of these methods requires a tremendous amount of time that prevents them from exploring complex pipelines to find better predictive models. To further explore this research challenge, we have conducted experiments showing that many of the generated pipelines are invalid, and it is unnecessary to execute them to find out whether they are good pipelines. To address this issue, we propose a novel method to evaluate the validity of ML pipelines using a surrogate model (AVATAR). The AVATAR enables to accelerate automatic ML pipeline composition and optimisation by quickly ignoring invalid pipelines. Our experiments show that the AVATAR is more efficient in evaluating complex pipelines in comparison with the traditional evaluation approaches requiring their execution
Adult Language Education and Migration
Adult Language Education and Migration: Challenging Agendas in Policy and Practice provides a lively and critical examination of policy and practice in language education for adult migrants around the world, showing how opportunities for learning the language of a new country both shape and are shaped by policy moves. Language policies for migrants are often controversial and hotly contested, but at the same time innovative teaching practices are emerging in response to the language learning needs of today’s mobile populations. This book: analyses and challenges language education policies relating to adult migrants in nine countries; provides a comparative study with separate chapters on policy and practice in each country; focuses on Australia, Canada, Spain (Catalonia), Finland, France, Ireland, the Netherlands, the UK and the US. Adult Language Education and Migration is essential reading for practitioners, students and researchers working in the area of language education in migration contexts
Readings in Targeted Maximum Likelihood Estimation
This is a compilation of current and past work on targeted maximum likelihood estimation. It features the original targeted maximum likelihood learning paper as well as chapters on super (machine) learning using cross validation, randomized controlled trials, realistic individualized treatment rules in observational studies, biomarker discovery, case-control studies, and time-to-event outcomes with censored data, among others. We hope this collection is helpful to the interested reader and stimulates additional research in this important area
Adult Language Education and Migration
Adult Language Education and Migration: Challenging Agendas in Policy and Practice provides a lively and critical examination of policy and practice in language education for adult migrants around the world, showing how opportunities for learning the language of a new country both shape and are shaped by policy moves. Language policies for migrants are often controversial and hotly contested, but at the same time innovative teaching practices are emerging in response to the language learning needs of today’s mobile populations. This book: analyses and challenges language education policies relating to adult migrants in nine countries; provides a comparative study with separate chapters on policy and practice in each country; focuses on Australia, Canada, Spain (Catalonia), Finland, France, Ireland, the Netherlands, the UK and the US. Adult Language Education and Migration is essential reading for practitioners, students and researchers working in the area of language education in migration contexts
Trends in participation, performance and career choice, among girls who are successful in mathematics.
Masters Degree. University of KwaZulu-Natal, Durban.Abstract available in the PDF.Page 54 is missing from this PDF. Please refer to the print copy of this thesis which is at the Edminson Library (Edgewood Campus) for page 54
Expectations and Realisations: Experiences of mature students returning to study in an institution of public sector Higher Education
This interactionist study follows a group of adults, who, after a break in their formal education, return to study in an institution of public sector higher education. It is based on a series of interviews, before and during the first year of their courses to examine their subjective interpretations of the reality of the return to study in comparison with what they expected it would be like.
The increasing numbers of adults returning to higher education through a variety of access courses would seem to make this an opportune time to examine such experiences. However, this research raises questions about why this should be the case and examines answers at the level of the institution and the individuals themselves. It addresses the claims that the reasons for the increase are based on ideological assumptions in line with social justice but the reality which meets this group questions whether in fact provision and practice is in line with philosophy and purpose.
By allowing a group of mature students to speak for themselves it questions the assumptions of those who would advocate a separate theory of adult education. Such humanistic beliefs may be within the perception of the educators but be beyond the reality or requirements of men and women who must fit their studies into already busy lives and who may thus have an instrumental approach to education. To suggest it should be otherwise is ethnocentric.
This study seeks to examine whether or not one particular polytechnic takes cognisance of the needs of adults to meet the aims it claims to hold at an ideological level. At the same time, however, it asks about the relevance of humanistic approaches considering the conflicting demands of accountability within the changing status of public sector higher education corporations
The uses of television broadcast-based distance education : a case study of Liberty Learning Channel programme.
Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2004.Education is considered as an essential tool for the long-term development of most countries. The provision of education to only part of a community or part of the world reinforces relative deprivation. To counteract such an effect, South Africa, a geographically large country, in which the population is scattered, where economic disparities are aligned to race, where qualified teachers and specialists in certain subject areas are scarce, and where there is an illiteracy rate of 29 percent, hope has been expressed that television broadcast based distance education may be a viable alternative to expanding formal education provision extensively and quickly. This study investigates the role of television broadcast-based distance education in South Africa as a possibility for extending the provision of formal education to large numbers of learners and how the South African Broadcasting Corporation (SABC) and the country 's Department of Education fulfils the promise of extending education. This objective was addressed by first giving a critique of conventional education systems and why distance education is an alternative option for provision of education. Further, the study traces a general picture of education in Africa and the educational situation in South Africa, highlighting the distance education scenario in South Africa , and investigates why distance education and particularly television broadcast-based distance education is crucial in the provision of education in developing countries in the face of the globalisation of mass communication and new information technologies. The study also investigates the complex issues involved in the production, distribution and consumption of Liberty Learning Channel Programme (a television programme which offers remedial support for matric (grade 12) and grade 10 to 11 students) by examining whether the producers and partners of the programme created a text which connects with the multi-cultural reality of teachers, learners and other viewers in South Africa; the role of the programme in the service of growth, reconstruction and development; why the programme is not popular among the youth; and what can be done to make it effective in enhancing teaching and learning; and the intertextuality, production and distribution of the programme. Information on the above aspects was gathered through the scannmg of relevant literature and by the use of ethnographic research procedures which included focus group interviews, in-depth interviews and participant observation. The study established that conventional systems of education and current educational practices have fallen short ofpreparing citizens with a strong foundation of general education. The study therefore offers distance education not only as an alternative to conventional education delivery at secondary and higher levels of education, but also as a low-cost alternative to expanding education. Constructivism is suggested as an alternative set of values that may significantly influence learning and that can help develop the kind of citizens who can be able to function successfully in real-word contexts. With regard to effectiveness of television broadcast-based distance education in teaching and learning, the study established that television is an effective means of achieving traditional educational goals, and that television broadcast-based distance education remains important especially in the developing countries in light of the need to increase access to education, redress the disparities caused by globalisation of mass communication and by lack of information and communication technologies. With regard to distance education in South Africa, the study found that there is both significant policy commitment and actual use of broadcast-based distance education in solving many of the country's education problems, but that there is an urgent need to improve the quality of that provision, particularly in formal education. On the complex issues involved in the production, distribution and the consumption of Liberty Learning Channel programme, the study found that the programme (aired live since 1993), is a production of Liberty Learning Channel, an independent company based in Johannesburg, in partnership with the Liberty Life Foundation, and that the SABC is not involved in the production but provided the airwaves. Each subject presenter prepares his or her own lessons, and therefore no services of producers, scriptwriters, or editors are employed in the production of the programme. The programme is then distributed through television, newspapers (the Sowetan), videocassettes, the Internet and in future through CD-ROMs. Additionally, the study found that Liberty Learning Channel relies on audience feedback from audience rating and occasional feedback from comments down the streets or letters from viewers thanking the presenters. This study argues that this kind of monitoring is not sufficient as rating only tells advertisers how many viewers were exposed to a specific programme content on a particular television channel in a certain time slot. Regarding the consumption of the programme, the great majority of the focus group participants liked the programme and used it during revision and in dealing with large numbers of students with different abilities and difficulties. A great majority of the students liked the programme because of the way the presenters explained clearly. However, a great majority of the participants watched the programme sparingly partly because the time slot was ' inappropriate ' and due to a lack of awareness about the programme. Several suggestions for the improvement of the programme were put forward, amongst them: to change the time slot; to have multi-racial presenters ; to give detailed timetables to schools in advance, and to advertise the programme more directly to schools. However, a reluctance or unwillingness to consider some of the audiences ' suggestions for the improvement of the programme, was shown by the manager of Liberty Learning Channel, William Smith. The above results are reported and discussed in detail in chapters 2 to 3, and general conclusions and recommendations presented in chapter 4