The access control mechanisms used in traditional security infrastructures, such as ACL and password applications, have been proven inadequate, inflexible, and difficult to apply in the Internet due to the incredible magnitude of today's Internet. Recently, research for expressing trust information in the digital world has been explored to be complementary to security mechanisms. This thesis deals with the access control for the resources provided over the Internet. On line digital content service is exemplary of such an application. In this work, we have concentrated on the idea of a trust management system, which was first proposed by Blaze et a1 in 1996, and we have proposed a general-purpose, application-independent Dynamic Distributed Trust Model (DDTM). In our DDTM, access rights are directly associated with a trust value. The trust values in this thesis are further classified into direct trust values, indirect trust values and trust authorization levels. We have calculated and expressed each type of the trust values as explicit numerical values. The core of this model is the recommendation-based trust model, organized as a Trust Delegation Tree (TDT), and the authorization delegation realized by delegation certificate chains. Moreover, the DDTM provides a distributed key-oriented certificate-issuing mechanism with no centralized global authority. A Dynamic Distributed Trust Protocol (DDTP) was developed as a general protocol for establishing and managing the trust relationship in a TDT structure. The protocol was verified by means of the verification tool, SPIN, and was prototyped to simulate communication and behaviors among the certificate issuer nodes on a TDT.

The main goal of this thesis is to discover how an emerging technological megatrend, the Internet of Things, changes the business model of the Microsoft OEM team. OEM business is fully dependent on sales of Windows licenses; however, the PC market is declining and whole Microsoft is shifting into offering of cloud services while being financed by the OEM revenues. Nevertheless, the strategy of how the OEM team fits into the future of cloud offerings is clearly missing. To discover what changes should be made inside the current business model, 13 interviews with managers across Microsoft were conducted and analyzed. Identified themes were assigned to business model building blocks, ranked by the importance, and supported by relevant quotes from interviews as well as the theoretical background. The most important subjects of changes were identified as partners, activities and value proposition; however, changes will be seen in every aspect of the OEM business. As a result, specific changes in building blocks are described and the first steps towards the Internet of Things strategy suggested. That will ensure the relevance of the conservative OEM team in the connected future.

Objetivo: estimar la frecuencia de adicción al internet en los estudiantes de 4to y 5to de secundaria del distrito de Chiclayo, Perú, 2015. Diseño: descriptivo de corte transversal. Se encuestó a los estudiantes de 4º y 5º de secundaria del distrito de Chiclayo, 2015. La muestra fue de 760 estudiantes de una población de 11878, con un nivel de confianza del 95% y un error permisible del 5%. Los sujetos estudiados han sido de estudiantes del 4º y 5º año de secundaria, con edades comprendidas entre 13 y 19 años. Se exploraron las características del uso del internet con un cuestionario tipo cerrado, y la adicción al internet por medio con el test de adicción al internet de Young, adaptado al Perú. Resultados: el 52,37% de los estudiantes encuestados, presentaron un nivel medio de la adicción al internet. El 57,1% fue de sexo femenino y el 41,71% tenía 15 años. Los estudiantes encuestados procedían de colegios públicos en el 52,63% de los casos. Un 52,2% de los estudiantes encuestados accedían al internet durante un tiempo menor a dos horas al día, y el 55,39% lo hacían desde un dispositivo móvil. El uso de comunicación-interacción social durante los fines de semana aumenta en 21% la probabilidad de presentar adicción al internet; así también las compras virtuales, en un 24%. Conclusiones: más de la mitad de estudiantes de 4to y 5to de secundaria presenta un nivel medio de adicción al internet. / Tesis

This study is dedicated to providing readers with a holistic overview of the phenomenon of the imitation among internet based companies. Four research questions have been posed and answered through qualitative primary and secondary researches. As a result of this study major success factors that allowed a Berlin - based company Rocket Internet SE to imitate ideas and business models of others have been identified, numerous recommendations have been provided to future copycat companies as well as to companies that face the pressure from such copycats in their day-to-day activities. As an outcome, more transparency has been provided about the processes of imitation in the business environment in order to allow various players to compete more effectively, structure their operations in more efficient way and avoid costly mistakes.

The diploma thesis concerns in two aspects which are the description of internet users and internet media. I show the ways of measuring visits, which is closely related to the operation of web sites and especially its economic aspect, the advertisement. I specify the indicators in view. I concentrate really carefully on the amount of real users, which is one of the most important indices. I apply the usage of these indices to practical examples. I point to sociodemographic user's profile of particular portals and compare them with other chosen servers. Consequently I determine specific recommendations for the advertisement submitters in the term of targeting their campaign accurately. By using many-variable statistical methods, I try to find out suitable groups of internet users based on their relation to advertisement. I consequently describe these groups of people and determine again certain recommendations.

M.A. / The goal of the present study was to investigate the relationship between personality traits, attitudes towards the Internet, and Internet use. This study was regarded as important because the Internet is increasingly becoming an important part of everyday life, and is changing society as we know it. 224 third year psychology students participated in the study. The existing literature indicated that the personality traits of Extraversion and Openness to Experience were likely to influence Internet use. Attitudes could also be expected to influence volitional behaviour, such as voluntary Internet use. Other research has also found exposure to be positively related to attitudes. A self-constructed questionnaire collected information relating to computer and Internet use, as well as attitudes towards the Internet. A short personality measure, namely the Saucier (1994) 40-ltem Mini-marker set, was used to measure the personality traits of participants. Examination of the results obtained through correlational and multiple regression techniques supported the existing theory. The personality traits of Extraversion and Openness to Experience were found to predict Internet use in certain situations, with Openness emerging as particularly important in understanding computer and Internet use. Attitudes formed by exposure to the Internet, as measured by the self-constructed Internet exposure scale, was found to correlate positively with time spent on the Internet. The study support previous studies which found that the personality traits of Extraversion and Openness influence media use, and suggest that this influence is also present in relation to Internet use. It also supported the theory that a positive relationship exists between attitudes towards the Internet, specifically attitudes formed by exposure, and frequency of Internet use.

This thesis is focused on online marketing and its application and use in hotel industry. The aim is to familiarise the reader with this issue and in the context of this objective create a study with a comprehensive view on online marketing in hotel industry, that is further complemented by the own research. In the context of primary research was determined the sub-objective - to analyse the situation of online marketing on the market of hotels in Prague, especially in terms of their internet presentation and advertising in search engines. The thesis is divided into three parts. First is a theoretical definition of online marketing, which is followed by secondary research concerning the usage of internet in the Czech Republic, then there is a mapping of the current situation in hotel industry, where is again used secondary research. The thesis concludes with primary research focused on the online marketing of hotels in Prague. Whole thesis is carried out in cooperation with the company Blueberry.cz Apps, s.r.o.

Digital advertising has seen dramatic growth over the last decade. Total digital ad spending in the US has increased 6 times between 2010 and 2020, from $26 billion to $152 billion(eMarketer). This impressive development has in turn sparked a huge stream of literature studying all the different aspects of advertising in the digital media. My dissertation contributes to this literature via two essays. In the first essay, I consider a very important topic of ad blocking, that in the recent years has become a significant threat to advertising supported content. With a specific focus on consumer and total welfare, I show the detrimental role of the adblockers’ current revenue model in decreasing content quality, consumer surplus and total welfare. In the second essay, I study demand learning in digital advertising markets, where firms learn over time how their advertising campaigns impact consumer demand by using their advertising campaign outcomes in earlier periods. By developing an analytic model, I demonstrate in several scenarios, such as monopoly and competition, that learning has an ambiguous effect on the key market parameters and, in particular, on the equilibrium advertising and quantities.

In 2004, the American College of Physicians joined with the National Library of Medicine in an effort to help patients find reliable health information free of commercial bias at the Web site MedlinePlus.gov. The aim of this study was to evaluate the usefulness of the MedlinePlus.gov site as perceived by patients who were referred to the site by their internist. Materials and Methods: A 27-item questionnaire developed by the American College of Physicians Foundation was distributed between January and May 2005 to a convenience sample of 893 adult patient volunteers attending 34 internal medicine practices across the United States. Results: The questionnaire revealed that although most patients (55%) routinely look up medical information, only 43% had used MedlinePlus.gov. Of those who had used the site, 95% were satisfied with the information they found there, and 94% said the information they found at MedlinePlus.gov would help them make better health decisions. Discussion: Patients who used the MedlinePlus.gov site at the recommendation of their physician found it easy to use, informative, and felt it would help them make better health decisions. Directing patients to this high quality, noncommercial, educational resource online may be an important adjunct to patient education efforts by physicians.

[pt] O mundo deparou-se com uma mudança eletrônica que afetou a forma como as pessoas se comunicam e que transformou toda a cadeia de valor, desde os produtores e vendedores até aos consumidores. A Internet revolucionou o marketing, que é definido como as trocas entre os indivíduos e as firmas. Comprar pela Internet está se tornando uma forma bem aceita de comprar vários tipos de produtos e serviços, incluindo produtos de computador, carros, viagens, investimentos, roupas, flores, livros, música e imóveis. Muitos fatores estão ajudando o desenvolvimento do mercado na Internet, alguns estão relacionados a avanços tecnológicos, outros à forma como o mundo corporativo mudou suas percepções e alguns relacionados à mudança do estilo de vida dos consumidores. O desenvolvimento de softwares de navegação e sistemas de busca melhores está transformando as visitas à Internet em experiência melhores e mais excitantes. O aumento da quantidade e qualidade de informação disponível e a presença de corporações e marcas conhecidas na Internet também estão gerando mais interesse por parte dos consumidores. Em 1995, as compras online eram uma novidade e esperava-se que chegassem a US bilhões no ano 2000 e a US,2 trilhões em 2003 (Forrester Research, 1998). Há um número crescente de companhias que podem ser acessadas pela Internet e que, consequentemente, provêm os consumidores com uma forma conveniente e barata de tornar-se um membro da comunidade da internautica. Porém, a maioria dessas empresas está perdendo dinheiro. Por que esse fenômeno aparentemente contrário à intuição está ocorrendo? A explicação pode estar nos riscos associados às compras pela Internet. Esses riscos podem surgir, porque os consumidores estão preocupados com a segurança da transmissão do número de seu cartão de crédito pela Internet, ou porque estão apreensivos em comprar algum produto sem tocá-lo, senti-lo ou ter dificuldades para devolvê-lo, caso não corresponda às suas expectativas. Tendo colocado isto, contudo, temos que afirmar que os consumidores estão comprando produtos pela Internet. Isto deve estar acontecendo, porque a percepção de risco associada com este tipo de compra está sendo contrabalançada pela sua conveniência. Esta dissertação tenta determinar porque alguns consumidores compram pela Internet e outros não. / [en] The world was come across with an electronic change that affected the form as the people if they communicate and that the value chain transformed all, since the producers and salesmen until the consumers. The InterNet revolutionized the marketing, that is defined as the exchanges between the individuals and the firms. To buy for the InterNet is if becoming one it forms well accepted to buy some types of products and services, being included products of computer, cars, trips,investments, clothes, flowers, books, music and property. Many factors are helping the development of the market in the InterNet, some are related the technological advances, others to the form as the corporative world changed its perceptions and some related to the change of the style of life of the consumers. The development of softwares of navigation and better systems of search is becoming the visits the InterNet in better and more exciting experiences. The increase of the amount and quality of available information and the presence of corporations and marks known in the InterNet also are generating more interest on the part of the consumers. In 1995, purchases online were a newness and expected that billions in year 2000 arrived the USS7 and expect that trillions in 2003 arrive the USS3.2 (Forrester Research, 1998). It has an increasing number of company that they can be had access by the InterNet and that, consequentemente, come the consumers with a convenient form and cheap to become a member of the community of the InterNet However, the majority of these store is losing money. Why this pparently contrary phenomenon to the intuition is occurring? The explanation can be in the risks associates to the purchases for the InterNet. These risks can appear, because the consumers are worried about the security of the transmission of the number of its credit card for the InterNet or, because they are apreensivos in buying some product without touching it, sentiz it or To have difficulties to return it, in case that it does not correspond to its expectations. Having placed this, however, we have that to affirm that the consumers are buying products for the InterNet. This must be happening, because the perception of risk associated with this type of purchase is being counterbalanced for its convenience. This dissertação tries to determine because some consumers buy for the InterNet and others not.