As aplicações de live streaming em redes P2P têm grande potencial de crescimento, em popularidade e qualidade, mas são potencialmente vulneráveis ao ataque de poluição de conteúdo. Tal ataque corresponde a qualquer adulteração de áudio e/ou vídeo na mídia transmitida buscando ludibriar espectadores. A autenticação de blocos do fluxo de dados contínuo (stream) permite a detecção de conteúdo poluído e a possível identificação de pares maliciosos na rede P2P. A literatura contém diversas propostas de autenticação baseadas em assinatura digital leve e em amortização de assinatura digital. O presente trabalho, como nenhum anterior, compara tanto os esquemas de assinatura leve quanto os de amortização sob diferentes perspectivas de qualidade de transmissão (vídeos convencionais e de alta definição) em redes P2P de live streaming através da formularização analítica dos mesmos. Para isto, é feita uma comparação quantitativa de sobrecargas e nível de segurança, observando fenômenos e identificando desafios de pesquisa que precisarão ser vencidos. Particularmente, para avaliar a viabilidade dos esquemas, foi definido um coeficiente que leva em consideração o tempo total de transmissão e o custo computacional proporcionado pelo esquema estudado. Como uma das conclusões inéditas dessa análise, o esquema PARM2 obteve o melhor desempenho dentre os esquemas leves de assinatura. Já em relação aos esquemas de amortização, o Linear Digests se sobressaiu entre os demais. Por fim, foi analisada uma solução baseada na amortização de um esquema de assinatura leve, algo também inédito. A partir dessa análise em particular, foi possível observar que a autenticação é viável apenas com baixos e médios níveis de segurança em transmissões convencionais. Além disso, a partir dos resultados foi possível observar que o esquema de amortização Linear Digests deve ser utilizado isoladamente apenas em transmissões convencionais. Por fim, o esquema PARM2, se utilizado individualmente, não apresenta valores de coeficiente aceitáveis para os cenários estudados. / P2P live streaming applications have great potential for improvements in terms of popularity as well as quality. However, they are subject to pollution attacks, in which a malicious user tampers with audio/video of streams in order to trick other users. The authentication of blocks in a stream allows the detection of pollution in received content and can lead to the identification of malicious users. The literature includes several proposals of light digital signature schemes and amortization schemes. Our work, unlike previous ones, compares both amortization schemes and light signature schemes under di erent perspectives of transmission quality (convencional and high definition videos) in P2P live streaming by formulating equations for them. For such, it quantitatively compares overheads and security levels during P2P streaming sessions, identifying research challenges to be faced. In particular, to assess the viability of such schemes, we defined a coe cient that takes into account the total transmission time and computational cost provided by such scheme. As one of the novel findings of our analysis, the scheme PARM2 showed the best performance among light signature schemes. With respect to amortization, Linear Digests was the most e cient. Finally, we analyzed a solution based on the amortization of a light signature. From this particular analysis, we observed that the authentication is only feasible in conventional transmissions with low and medium security leves. In addition, the amortization scheme Linear Digests must be used in isolation only in conventional transmissions. Finally, the scheme PARM2, if used alone, has no acceptable coe cient values for the studied scenarios.

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-11-28T13:37:42Z No. of bitstreams: 1 Dissertação - Maiara S. Coelho.pdf: 3183359 bytes, checksum: 67664d4cc48ed95893baa5a29f336b43 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-11-28T13:37:56Z (GMT) No. of bitstreams: 1 Dissertação - Maiara S. Coelho.pdf: 3183359 bytes, checksum: 67664d4cc48ed95893baa5a29f336b43 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-11-28T13:38:13Z (GMT) No. of bitstreams: 1 Dissertação - Maiara S. Coelho.pdf: 3183359 bytes, checksum: 67664d4cc48ed95893baa5a29f336b43 (MD5) / Made available in DSpace on 2016-11-28T13:38:13Z (GMT). No. of bitstreams: 1 Dissertação - Maiara S. Coelho.pdf: 3183359 bytes, checksum: 67664d4cc48ed95893baa5a29f336b43 (MD5) Previous issue date: 2015-12-18 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Due to increasing demand of HTTP Adaptive Streaming (HAS) in the last years, se-veral studies have been performed to develop multimedia content distribution techniques to the Internet, aiming to improve the users Quality of Experience (QoE). Techniques such as algorithms that automatically adjust the bit rates to network conditions during a video session and algorithms that assist in the preparation of multimedia content for access by customers. Although there are a large number of studies in this area, many have not explored network resource sharing scenarios between multiple clients and little have investigated issues relating to preparation of the content multimedia. Making it necessary to study more about this complex scenario for the future to ensure a fairer distribution of network resources, furthermore users can experience similar qualities. In addition, pre-paration of the content should be viewed as an important process such as the adaptive algorithms for better distribution of the content and to improve the QoE. This work pre-sents a video stream adaptation strategy that takes into account factors related to QoE, as the playback interruption frequency. The goal is to minimize the amount of video playback interruption, thereby improving its continuity. The experiments are performed in different network scenarios for one client and in extreme resource scarcity scenarios on a share across multiple clients. Furthermore, we experienced versioning videos with different granularity and FPS (frames per second). In the results, the used metrics are average video bit rate, probability of interruptions, instability and fairness. In addition, this work presents the study of the impact of the strategy on such metrics. / A ampla adoção do Streaming Adaptativo sobre HTTP tem motivado estudos relacionado as técnicas de distribuição de conteúdo multimídia na Internet. Os esforços têm sido no sentido de desenvolver novas estratégias de acesso a esse conteúdo considerando o modelo de serviço de melhor esforço implementado na Internet. Apesar da grande quantidade de estudos, poucos exploram cenários de compartilhamento da rede de acesso entre clientes e investigam questões relacionadas à preparação do conteúdo distribuído. Investigar a dinâmica de acesso, em ambiente compartilhado, tem como motivação principal melhorar a QoE dos usuários, minimizando o número de interrupções experimentadas pelos usuários do sistema de distribuição do conteúdo. Por outro lado, a preparação do conteúdo visa um ajuste com a estratégia de acesso proposta, ao mesmo tempo que se reconhece os limites dos recursos de armazenamento e transmissão. Nesta dissertação apresenta-se uma estratégia para acesso a conteúdo multimídia que compreende em re-comendações de versionamento e um algoritmo adaptativo, o versionamento é preparado conforme a padronização DASH e o algoritmo reconhece as condições da rede, além disso suas decisões são baseadas na frequência de interrupção da reprodução. A estratégia proposta melhora a continuidade da sessão de acesso, um parâmetro de QoE importante no contexto de transmissão de streaming de vídeo. Nos primeiros resultados numéricos foram avaliados diferentes valores de granularidade da taxa de bits e de volume do fluxo de dados. No posteriores foram avaliadas as seguintes métricas: i) taxa de bits média, ii) número e duração das interrupções e iii) instabilidade e justiça, em diferentes cenários de rede, caracterizados pelo compartilhamento com vários clientes.

Syftet med denna kvalitativa studie är att undersöka hur skivbranschverksamma personer kan resonera kring inspelning av fullängdsalbum samt distribution av dessa nu i en tid när musik distribueras såväl genom digitala releaser som fysiska utgivningar. Forskningsfrågorna behandlar hur dessa personer ser på den intresseförändring som skett under de senaste 20 åren inom branschen gällande inspelning av fullängdsalbum, samt om man helst väljer att släppa musik digitalt eller på ett fysiskt medium. Intervjuer med tre stycken mycket erfarna personer inom skivbranschen har genomförts, där informanternas utsagor sedan har analyserats med begrepp hämtade från en darwinistisk teori. Undersökningens resultat indikerar att det har skett en intresseförändring under de senaste 20 åren och att skivbranschen idag fokuserar mer på digitala releaser än fysiska utgivningar samt att singlar premieras framför fullängdsalbum. Undersökningens resultat överensstämmer väl med den tidigare forskningen inom kunskapsområdet.

The aim of this study is to examine Japanese gendered language use in online game streaming, and the differences in gendered language use between male and female streamers. The main aim of this thesis is to examine how, and to what extent, young Japanese adults use gendered language when broadcasting gaming streams online. I will examine how pronounced the differences in gendered language use are between male and female streamers, and see if the major theories about gendered language apply in the Japanese streaming community. To collect the data, I looked at 20 game streamers, with each stream lasting 15-30 minutes. I transcribed the streamers’ commentary, and examined the frequency of certain sentence ending particles, personal pronouns, and polite speech/word choice. The streamers were chosen with regards given to certain criteria to prevent skewed results, and to control the independent variables to a certain extent. For example, the streamers must be playing alone to ensure that the streamer is the only person speaking. I analyzed the results using a qualitative method, which indicated that the greater gender differences are found in the use of personal pronouns, but not as much in the use of sentence ending particles or politeness level.

Linnaeus University is aiming at implementing a Data Stream Centre to provide streaming of accumulated data from the websites’ newspapers and articles in order to help its scientists of University to have faster and easier access to the mentioned data. This mentioned project consists of multiple parts and the part we are responsible to research about is first nominating some text streaming protocols based on the criteria that are important for Linnaeus University and then evaluating them. Those protocols are responsible to transfer text stream from the robots (that read articles from the websites) to the data stream center and from them to the scientists. Some KPIs (Key Performance Indicators) are defined and the protocols are evaluated based on those KPIs. In this study we address evaluation of network streaming protocol by starting to read about the protocol’s specifications and nominating four protocols including TCP, HTTP1.1, Server-Sent Events and Websocket. Then, fake robot and server are implemented by each protocol to simulate the functionality of real robots, servers and scientists in LNU data stream center project. Later, the evaluation is done in the mentioned simulated environment using RawCAP, Wireshark and Message Analyzer. The results of this study indicated that the best suited protocols for transferring text stream data from robot to data stream center and from data stream center to scientist are TCP and Server-Sent Events, respectively. In the concluding part, other protocols are also suggested in the order of priority.

The Internet of Things (IoT) is a concept that revolves around ordinary devices that are connected to the internet for extended control and ease of use. Altran, a company dealing in high technology and innovation consultancy, predicts a large growth in business opportunities in the IoT area in the coming years, and therefore wants to invest in knowledge about the Internet of Things. Altran wanted a report that described popular wireless IoT communication technologies along with a proposal for a general IoT communication platform or base that could be used to implement many of these technologies. Additionally, an audio streaming application were to be implemented on the proposed platform to validate its credibility. The project resulted in a report on 6 different wireless IoT technologies: Z-wave, ZigBee, Thread, Bluetooth, 802.11n, and 802.11ah. A hardware and software base was proposed that could implement 4 of 6 of these technologies. This base was the Raspberry Pi 2 along with the Raspbian Jessie operating system. Finally an audio streaming system that could stream data to a set of smart Speaker nodes over wireless links based on IEEE 802.11n was implemented on the proposed base.

This project investigates the importance of availability in the scope of dictation programs. Using speech recognition technology for dictating has not reached the public, and that may very well be a result of poor availability in today’s technical solutions. I have constructed a persona character, Johanna, who personalizes the target user. I have also developed a solution that streams audio into a speech recognition server and sends back interpreted text. Johanna affirmed that the solution was successful in theory. I then incorporated test users that tried out the solution in practice. Half of them do indeed claim that their usage has been and will continue to be increased thanks to the new level of availability.

Technology non-use or active resistance towards technology is a pertinent issue in Human Computer Interaction, especially when we contemplate the ongoing changes regarding the concept of usability. By combining Theory of Practice and Theory of Materiality with Theory of Affect this thesis explores the resistance towards online streaming music technology among music enthusiasts devoted to vintage Vinyl music culture and also takes an effort to understand any possible effect of this voluntary non-use on the digital music industry. Qualitative research analysis is employed on ten in-depth semi structured interviews showing that material aspects and nostalgia, create an individualistic image and passion for record collection; furthermore, these aspects play a role behind the choice of non-use of online music technology.

Följande studie undersöker vilka egenskaper konsumenter letar efter vid val av musikstreamingtjänst och huruvida det skiljer sig mellan konsumenter med musikalisk bakgrund och de utan musikalisk bakgrund. Studien undersöker musikkonsumentens nyttjande av musikstreamingtjänster, vilka egenskaper de värderar högst hos sina musikstreamingtjänster och vilka egenskaper de saknar. Studien har genom en kvantitativ metod, där en enkätundersökning har legat till grund för empiriinsamlingen, kommit fram till slutsatsen att musikkonsumenter letar efter ett stort och brett musikbibliotek, ett bra användargränssnitt, låg kostnad, exklusivt material, teknologiska funktioner, social interaktion och ljudkvalitet. Studien har även kommit till slutsatsen att lyssnarvanor skiljer sig mellan olika konsumenter, vi kan se att konsumenter med musikalisk bakgrund lyssnar mer frekvent och aktivt på musik. I uppsatsen används bland annat Lars Lilliestam teori om aktiv och passiv lyssning (Lilliestam, Lars, 2009, s. 93). Lars redogör för innebörden av aktiv lyssning, det är när man ger sin fulla koncentration och uppmärksamhet till musiken.

Video streaming is an important field of global communications and data processing. It is divided into server and client sides connected via network. Video streaming is concerned with delivering video data from server to client over the network as fast and with as little loss as possible. In this study the possibilities to minimize the amount of data transferred over the network in video streaming are investigated and a video streaming technique comprised of server and client sides is proposed. To expand the flexibility and adaptability of the proposed video streaming technique an operational parameter system was constructed and the parameter value ranges were defined. The proposed video streaming technique was then applied to three sample videos. Before streaming the server side of the proposed technique reduced the frame count of input videos based on operational parameter values while the client side reconstructed the skipped frames. Then the quality of the resulting videos was measured and evaluated. To evaluate the reconstructed frames and videos the PSNR measurement method was used. The study concludes that by using the proposed video streaming technique it is possible to reduce the amount of transfer data by dropping frames on the server side and reconstructing them on the client side.