Orientadores: Akebo Yamakami, Tiago Agostinho de Almeida / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-22T13:22:48Z (GMT). No. of bitstreams: 1 Silva_RenatoMoraes_M.pdf: 4136928 bytes, checksum: 218846058592353cb167c8c2d61e1bfd (MD5) Previous issue date: 2013 / Resumo: Com o crescente aumento do volume de informações disponíveis na Web, as ferramentas de busca tornam-se cada vez mais importantes para os usuários da Internet. Consequentemente, com o objetivo de se tornar mais visíveis, os sites concorrem entre si para ganhar melhores posições nos resultados das buscas feitas por esses usuários. Porém, muitos ganham maior visibilidade através de estratégias que enganam as ferramentas de busca. Esses sites, conhecidos como Web spam, causam prejuízos pessoais e econômicos aos usuários. Diante desse cenário, este trabalho apresenta uma análise do desempenho de diversos métodos de aprendizado de máquina aplicados na detecção automática de Web hosts que propagam Web spam. Os experimentos foram realizados usando duas bases de dados reais, públicas e de grande porte, das quais foram extraídos três diferentes conjuntos de vetores de atributos: baseados no conteúdo das páginas Web, baseados nos links das páginas Web e formados pela transformação dos atributos baseados nos links. Também foi analisada a viabilidade da redução de dimensionalidade do espaço dos atributos. Outra contribuição desse trabalho é a proposta de uma abordagem de classificação de Web spam, em que as predições obtidas com cada tipo de vetor de atributos são combinadas e uma decisão final é obtida usando-se voto majoritário simples. Os resultados obtidos indicam que os métodos de bagging de árvores de decisão, redes neurais perceptron de múltiplas camadas, floresta aleatória e boosting adaptativo de árvores de decisão são promissores na tarefa de detecção de Web spam. Além disso, verificou-se que os métodos de aprendizado tem melhor desempenho quando os vetores de atributos baseados no conteúdo e os vetores formados pela transformação dos atributos baseados nos links são combinados. Por fim, a combinação das predições obtidas com cada tipo de vetor de atributos gera bons resultados e por isso, essa é uma abordagem recomendada para o combate de Web spamming / Abstract: Due to the increasing volume of information available on the Web, search engines become increasingly important to Internet users. Consequently, with the purpose of becoming more visible, the Web sites compete to achieve better positions in the results of the searches made by such users. However, many of them achieve a good visibility through strategies that try to circumvent the search engines. This kind of Web sites are known as Web spam and they are responsible for personal injury and economic losses to users. Given this scenario, this work presents a performance analysis of established machine learning techniques employed to automatically detect Web hosts that disseminate Web spam. The experiments were performed with two real, public and large datasets, from which were extracted three different sets of features vectors: contentbased ones, link-based ones and features vectors generated by the transformation of the link-based features. We also analyzed the viability of the dimensionality reduction of the feature space. Another contribution of this work is the proposal of a Web spam classification approach which combines the predictions achieved by each type of features vector and using a simple majority voting. The results indicate that bagging of decision trees, multilayer perceptron neural networks, random forest and adaptive boosting of decision trees are promising in the task of spam hosts classification. Furthermore, we have conclude that the learning techniques perform better when we have combined the content-based features vectors and the features vectors generated by the transformation of the link-based features. Finally, the combination of the predictions achieved with each type of features vector has achieved superior results and therefore it is a recommended approach to automatically detect Web spam / Mestrado / Automação / Mestre em Engenharia Elétrica

SMTP, the current protocol for sending electronic mail (e-mail) over the Internet, has for many years suffered from several problems and limitations. When it was designed, well over twenty years ago, the requirements for e-mail were very different from those of today. A message was a text message in English, and both user and machine were explicitly named in the address. The protocol was not designed to transfer other types of messages, and no mechanism was included to verify the identity of the sender. In order to solve these shortcomings, a new e-mail protocol needs to be defined. This report specifies a basis for what such a protocol may look like. The protocol has been designed to be easy to modify and expand, as well as to benefit from more recent ideas and technology. Binary message content is transferred without conversion, sender addresses are verified, and the address format is flexible. Along with the specification of the protocol, a sample implementation has been provided.

The existance of spam email has gone from a fairly small amounts of afew hundred in the late 1970’s to several billions per day in 2010. Thiscontinually growing problem is of great concern to both businesses andusers alike.One attempt to combat this problem comes with a spam filtering toolcalled TRAP. The primary design goal of TRAP is to enable tracking ofthe reputation of mail senders in a decentralized and distributed fashion.In order for the tool to be useful, it is important that it does not haveany security issues that will let a spammer bypass the protocol or gain areputation that it should not have.As a piece of this puzzle, this thesis makes an analysis of TRAP’s protocoland design in order to find threats and vulnerabilies capable of bypassingthe protocol safeguards. Based on these threats we also evaluate possiblemitigations both by analysis and simulation. We have found that althoughthe protocol was not designed with regards to certain attacks on the systemitself most of the attacks can be fairly easily stopped.The analysis shows that by adding cryptographic defenses to the protocola lot of the threats would be mitigated. In those cases where cryptographywould not suffice it is generally down to sane design choices in the implementationas well as not always trusting that a node is being truthful andfollowing protocol.

Submitted in fulfilment of the requirement for Masters in Management Sciences specialising in Public Relations, Durban University of Technology, Durban, South Africa. 2017. / In South Africa the National Plan for Higher Education (NPHE, 2001) brought with it distinct changes to the higher education landscape. Amongst the major changes were the mergers of various higher education institutions. In 2005, the Walter Sisulu University for Technology (WSU) was established through the merger of the former Border Technikon, Eastern Cape Technikon and the University of Transkei. The University caters for students from the Eastern Cape’s Border and Kei regions resulting in communication with a large number of stakeholders. Effective communication as well as developing and maintaining relationships with key stakeholders therefore become pivotal. This study set out to examine the perceived effectiveness of communication strategies between the Walter Sisulu University and students. A mixed method approach found that although respondents felt that communication was satisfactory, concerns were however, raised about the effectiveness of the communication strategies being utilised. The study recommended e-communication as a key strategy to facilitate communication with students. / M

At present, the average employee is being bombarded with an ever-increasing number of messages information on his/her company, its products and services, as well as information on its strategy all flooding in from a myriad of sources, including internal vehicles such as e-mail, the intranet, management memoranda, internal publications, as well as the external media, such as the Internet, the local newspaper, television news and national business and industry magazines. The term “information overload” is usually understood to present a state of affairs where an individual’s efficiency in using information in his/her work is hampered by a surplus amount of relevant and potentially useful information available to him/her. The principal aim of this study, therefore, is to establish the extent and impact of information overload on the knowledge worker in the banking industry, with special reference to the part that e-mail technology plays in the creation of such overload. Broadcasting, the telephone and the Internet have revolutionised the way in which workers communicate around the globe. Electronic-messaging systems such as e-mail have become the medium of choice in many organisations, and hold significant and valuable business data, information and knowledge. These systems have had a profound impact on the way in which personal and business communications are effected in the office. With e-mail having acquired mission-critical status, a number of concomitant circumstances and consequences have arisen that present organisations, such as banks, with a variety of challenges, among which • the impact on employees’ productivity, owing to the time spent on e-mailing activities • employees’ attitudes towards e-mail • compliance with corporate policies, such as those policies governing electronic communication and computer use • surveillance and monitoring of e-mail • the quest for finding formal archiving solutions. / Prof. C.W. Rensleigh

Bibliography: pages 233-235. / The CCITT X.400 Message Handling System resides in the Application Layer of the seven-layer Reference Model for Open Systems Interconnection. It bypasses the services of the Presentation Layer completely to interact directly with the Session Layer. The objectives of this thesis are to show how the general Session Layer may be tailored to be minimally conformant to the requirements of X. 400; to produce a formal specification of this session layer; and to show how this session layer may be implemented on a real system. The session services required by X. 400 are those of the Halfduplex, Minor Synchronization, Exceptions and Activity Management functional units of the CCITT X.215 Session Service Definition. These services, and particularly their use by X.400, are described in detail. State tables describing these services are derived from the general session service state tables. Those elements of the CCITT X. 225 Session Protocol Specification which are required to provide only those services required by X. 400 are described in detail. State tables describing this session protocol are derived from the general session protocol state tables. A formal specification of the session layer for X.400 is presented using the Formal Description Technique Estelle. This specification includes a complete session entity, which characterizes the entire session layer for X.400. A session entity for supporting X.400 is partially implemented and interfaced to an existing X.400 product on a real system. Only the Session Connection Establishment Phase of the session protocol is implemented to illustrate the technique whereby the entire session protocol may be implemented. This implementation uses the C programming language in the UNIX operating system environment.

This thesis has focused on development of library of IMAP network protocol in C++ programming language. This work has focused on design and on interface of the library. Object design of this library is based on analysis of the IMAP protocol. Developed library contains implementation of a client and server part of the IMAP protocol. This work shows also the another IMAP libraries and evaluates pros and cons of the different solutions. Security of a network transfer is explained here in this thesis. This work deals with authentication methods, which are used to protect user credentials during authentication process. Created library can be easily used by software developers to develop an applications like an email client program and IMAP mail server. Part of this work has focused on testing of this developed library.

Within the context of social networks, existing methods for document classification tasks typically only capture textual semantics while ignoring the text’s metadata, e.g., the users who exchange emails and the communication networks they form. However, some work has shown that incorporating the social network information in addition to information from language is useful for various NLP applications, including sentiment analysis, inferring user attributes, and predicting interpersonal relations. In this thesis, we present empirical studies of incorporating social network information from the underlying communication graphs for various text classification tasks. We show different graph representations for different problems. Also, we introduce social network features extracted from these graphs. We use and extend graph embedding models for text classification. Our contributions are as follows. First, we have annotated large datasets of emails with fine-grained business and personal labels. Second, we propose graph representations for the social networks induced from documents and users and apply them on different text classification tasks. Third, we propose social network features extracted from these structures for documents and users. Fourth, we exploit different methods for modeling the social network of communication for four tasks: email classification into business and personal, overt display of power detection in emails, hierarchical power detection in emails, and Reddit post classification. Our main findings are: incorporating the social network information using our proposed methods improves the classification performance for all of the four tasks, and we beat the state-of-the-art graph embedding based model on the three tasks on email; additionally, for the fourth task (Reddit post classification), we argue that simple methods with the proper representation for the task can outperform a state-of-the-art generic model.

The objectives of this study were (1) to identify and describe task-based documentation; (2) to identify and describe any purported changes in users attitudes when IT migration was preceded by task-based documentation; (3) to suggest implications of task-based documentation on users attitude toward IT acceptance. Questionnaires were given to 150 university students. Of these, all 150 students participated in this study. The study determined the following: (1) if favorable pre-implementation attitudes toward a new e-mail system increase, as a result of training, if users expect it to be easy to learn and use; (2) if user acceptance of an e-mail program increase as expected perceived usefulness increase as delineated by task-based documentation; (3) if task-based documentation is more effective than standard help menus while learning a new application program; and (4) if training that requires active student participation increase the acceptance of a new e-mail system. The following conclusions were reached: (1) Positive pre-implementation attitudes toward a new e-mail system are not affected by training even if the users expect it to be easy to learn and use. (2) User acceptance of an e-mail program does not increase as perceived usefulness increase when aided by task-based documentation. (3) Task-based documentation is not more effective than standard help menus when learning a new application program. (4) Training that requires active student participation does not increase the acceptance of a new e-mail system.

The purpose of this study was (a) to investigate the functional use of e-mail in a university setting and the relationship of attitudes toward and self-efficacy with email technology, and (b) to evaluate writing effectiveness in an electronic medium. The study also sought to determine if certain personal characteristics could serve as predictor variables for explaining e-mail use, attitudes toward email, and self-efficacy with e-mail technology. The population of interest was the teaching faculty at Virginia Polytechnic Institute and State University who had a published e-mail address. A random sample of 500 faculty were sent a survey via campus mail. A total of 262 usable responses provided data for statistical treatment which included factor analysis and multiple regression. Additionally, 30 self-selected respondents provided copies of e-mail messages they had written. These messages were rated holistically for writing effectiveness, and the ratings were examined for their relationship with the extent of e-mail use, attitudes toward e-mail, and self-efficacy with e-mail technology. The items on the attitude toward e-mail scale clustered into two factors, "Usefulness," and "Comfort/Anxiety." The items on the e-mail purposes of use scale also clustered into two factors, "Task Use," and "Social Use." These factors were similar to the ones on the instruments from which this study's instrument was adapted. The results of the regression analyses indicated that several of the variables were significant predictors of e-mail use, attitudes toward e-mail, and self-efficacy with e-mail technology. An attitude of e-mail's usefulness and self-efficacy with e-mail technology were significant predictors of the extent of e-mail task and social use. Self-efficacy was a significant predictor of positive attitudes of usefulness and comfort. Age was a significant predictor of social use of e-mail as well as of a positive attitude of e-mail's usefulness. Years e-mail had been used was a significant predictor of the extent of e-mail use and of self-efficacy. Higher ranking teaching faculty had more positive attitudes of e-mail's usefulness. The results of analyses of holistic ratings indicate no significant correlations existed among the variables. Recommendations for instruction and for further research are described. / Ph. D.