Building a Better Tor Experimentation Platform from the Magic of Dynamic ELFs

Tor is the most popular tool for providing online anonymity. It is used by journalists, activists, and privacy-conscious individuals to provide low-latency private access to the Internet. However, Tor’s specific design and implementation is constantly changing to improve the performance and privacy properties it seeks to provide. To test these improvements, some form of experimentation is needed. Running experiments directly on the real Tor network is often not a viable option. The users of Tor are using it presumably because of its privacy protections, and caution must be taken to avoid recording or revealing information from non-consenting parties, particularly when dealing with shortcomings in Tor’s privacy protections or using new, untested versions of Tor. Because of the need for reproducible experiments and the aforementioned ethical requirements surrounding Tor experimentation, it is often necessary to use artificially constructed Tor networks. Several tools are available to construct such networks, such as network emulators like NetMirage, and simulators like Shadow. However, these existing tools do not provide the scalability that would be desirable when running experiments on these networks — with emulators requiring hardware capable of running all hosts in real time simultaneously, and with Shadow (the only maintained network simulator capable of running Tor code) having performance constrained by early design decisions. Since the behavior of a network can change with its size, it is better to use larger networks that more closely resemble the size of the real deployed network. Additionally, the ability to test the functional correctness of a modification to the Tor source code is considerably simpler when there is a means of quickly experimenting on a virtual Tor network to run such tests. In both of these cases, a higher-performance testing platform is needed. To address this shortcoming, for this thesis we designed and implemented a new model of Tor network simulation, centered around a modified version of the Shadow network simulator, using large numbers of dynamically loaded binaries. This is accomplished by implementing a custom dynamic loader, which we call drow-loader, that allows for dynamically loading more binaries than any other dynamic loader that we are aware of, and with better performance. By using the features of this dynamic loader, we are able to run simulated processes isolated in “namespaces”. This allows for reduced lock contention, simpler process modeling, and the ability to migrate simulated processes between worker threads. Using simulated Tor networks ranging from hundreds to tens of thousands of hosts, we then demonstrate the performance improvements our simulation technique provides over the state of the art

Player agency in interactive narrative: audience, actor & author

The question motivating this review paper is, how can computer-based interactive narrative be used as a constructivist learn- ing activity? The paper proposes that player agency can be used to link interactive narrative to learner agency in constructivist theory, and to classify approaches to interactive narrative. The traditional question driving research in interactive narrative is, ‘how can an in- teractive narrative deal with a high degree of player agency, while maintaining a coherent and well-formed narrative?’ This question derives from an Aristotelian approach to interactive narrative that, as the question shows, is inherently antagonistic to player agency. Within this approach, player agency must be restricted and manip- ulated to maintain the narrative. Two alternative approaches based on Brecht’s Epic Theatre and Boal’s Theatre of the Oppressed are reviewed. If a Boalian approach to interactive narrative is taken the conflict between narrative and player agency dissolves. The question that emerges from this approach is quite different from the traditional question above, and presents a more useful approach to applying in- teractive narrative as a constructivist learning activity

Fifth NASA Goddard Conference on Mass Storage Systems and Technologies

This document contains copies of those technical papers received in time for publication prior to the Fifth Goddard Conference on Mass Storage Systems and Technologies held September 17 - 19, 1996, at the University of Maryland, University Conference Center in College Park, Maryland. As one of an ongoing series, this conference continues to serve as a unique medium for the exchange of information on topics relating to the ingestion and management of substantial amounts of data and the attendant problems involved. This year's discussion topics include storage architecture, database management, data distribution, file system performance and modeling, and optical recording technology. There will also be a paper on Application Programming Interfaces (API) for a Physical Volume Repository (PVR) defined in Version 5 of the Institute of Electrical and Electronics Engineers (IEEE) Reference Model (RM). In addition, there are papers on specific archives and storage products

Player Agency in Interactive Narrative: Audience, Actor & Author

The question motivating this review paper is, how can computer-based interactive narrative be used as a constructivist learn- ing activity? The paper proposes that player agency can be used to link interactive narrative to learner agency in constructivist theory, and to classify approaches to interactive narrative. The traditional question driving research in interactive narrative is, ‘how can an in- teractive narrative deal with a high degree of player agency, while maintaining a coherent and well-formed narrative?’ This question derives from an Aristotelian approach to interactive narrative that, as the question shows, is inherently antagonistic to player agency. Within this approach, player agency must be restricted and manip- ulated to maintain the narrative. Two alternative approaches based on Brecht’s Epic Theatre and Boal’s Theatre of the Oppressed are reviewed. If a Boalian approach to interactive narrative is taken the conflict between narrative and player agency dissolves. The question that emerges from this approach is quite different from the traditional question above, and presents a more useful approach to applying in- teractive narrative as a constructivist learning activity

Bowdoin Orient v.121-122, no.1-21 (1991-1992)

https://digitalcommons.bowdoin.edu/bowdoinorient-1990s/1003/thumbnail.jp

A representação emocional da personagem virtual no contexto da animação digital : do cinema de animação aos jogos digitais

Tese de doutoramento em Ciências da Comunicação (área de especialização em Comunicação Audiovisual)O fenómeno da proliferação de personagens virtuais nos mais variados contextos das indústria criativa e do entretenimento — especialmente no cinema de animação e nos jogos digitais — reflectem aspectos de uma cultura (audio)visual digital exigente de novas linguagens e emoções. Esta nova cultura da imagem espectacular e da animação computadorizada emergiu, a partir dos anos 70, diluída entre as fronteiras do filme capturado por uma câmara de vídeo, e das imagens animadas geradas por computador, desafiando os limites da imagem animada. O modo como a introdução destas novas técnicas e estilos se posiciona no processo criativo da produção clássica da animação de personagens, e se espalha pelos diversos objectos e conteúdos dos novos media, suscita novas prorrogativas, obrigando, como alguns autores sugerem, ao reposicionamento do estudo da animação. O uso do computador como um meio de novas possibilidades de criação traz à tona novas experiências emotivas e linguagens estilísticas. E é no campo da animação digital 3D que a mudança visual é mais significativa, surgindo regularmente inovadoras técnicas de manipulação da imagem com uma maior preocupação no desenvolvimento de personagens virtuais, em última instância, pivot e protagonista de múltiplas experiências visuais, comunicacionais e narrativas, sujeitas a um olhar de uma câmara que não conhece limites físicos. Esta imagem animada que nos possibilita um autêntico mergulho nos seus mais ínfimos detalhes, e resiliente o suficiente para ser partilhada por áreas como os jogos digitais e o cinema de animação, é um dos aspectos que nos leva a questionar acerca da dimensão da personagem virtual na contemporaneidade. Nesse sentido, a presente tese tem como objectivos centrais apontar hipóteses sobre os alicerces que levam à construção de uma “humanização” da personagem virtual, no sentido de uma representação credível de experiências reais como a tristeza, o ciúme, o medo, e outras emoções humanas. Para isso, o nosso estudo recaiu na análise de várias dimensões, modelos e aspectos clássicos da animação, com enfâse no contexto do desenvolvimento de personagens, procurando compará-los com os novos paradigmas definidos pelas novas rotinas do cinema de animação e jogos digitais. Com esta formulação foi necessário criar uma área transversal que abrangesse diversos campos de conhecimento, nomeadamente, o design de personagem, a interpretação teatral e, claro, a animação digital, palavras-chaves da nossa investigação. O resultado desta diligência permitiu encontrar novas características e mecanismos que tornam possível estabelecer um modelo de dimensões da personagem virtual com vista a uma experiência imersiva. Neste contexto, foi imprescindível proceder a um estudo aplicado para testar a veracidade das nossas conjecturas teóricas. Assim, procedemos ao desenvolvimento de uma personagem virtual e, posteriormente, à criação de um projecto interactivo, numa primeira fase, e uma curta-metragem de animação numa fase final. Ambas, a personagem e a curta metragem de animação, foram elaboradas tendo em vista os pressupostos resultantes da investigação teórica. Os resultados apresentados validam o nosso modelo dimensional demonstrando que, de facto, a credibilidade da animação de uma personagem virtual responde a um conjunto de prorrogativas que estão cada vez mais enraizados na arte e na indústria criativa.The proliferation of virtual characters in a broad range of contexts within the creative and entertainment industries — especially in animated films and digital games — reflects aspects of a digital (audio)visual culture that demands new creative languages and emotions. This new culture of extravagant images and computerised animation emerged in the 1970s as a confluence of the frontiers of film captured by a video camera and those of images generated on a computer, testing the very limits of the animated image. The way in which these new techniques and styles position themselves in the creative process for classic character animation and spread to a variety of subjects and content in new media requires new approaches and, indeed, as some authors suggest, a repositioning when it comes to animation studies. The use of the computer with its new creative possibilities brings to light new emotive experiences and stylistic methods of expression. The visual change is most noteworthy in the field of 3D digital animation, where innovative image manipulation techniques regularly emerge with a greater focus on developing virtual characters who, ultimately, serve as focal points and protagonists for multiple visual, communicational and narrative experiences, subject as they are to the gaze of a camera without physical limitations. This new animated image, which allows us to truly explore the most intricate details of the animated image and is resilient enough to be shared by a variety of fields such as digital games and animated films, is one of the aspects that brings us to question the role which the virtual character plays in contemporary society. Accordingly, this paper aims to develop hypotheses on the foundations that lead to the construction of a “humanisation” of virtual characters, which in this case refers to credible representations of real experiences such as sadness, jealousy, fear and other human emotions. To this end, our study analysed a range of classic dimensions, models and aspects of animation with an emphasis on character development in order to compare them to the new paradigms established by the new routines in animated films and digital games. This objective required the creation of a peripheral area that encompasses various fields of knowledge, namely, character design, theatrical interpretation and, of course, digital animation, all of which have served as keywords for our investigation. The result of this endeavour allowed us to discover new characteristics and mechanisms which made it possible to establish a theory of patterns and dimensions for virtual characters with an eye toward immersive experiences. In this context, it was absolutely necessary to proceed with an applied study to test the veracity of our theoretical conjectures. We therefore developed a virtual character and, later, an interactive project in the first stage and created a short animated film in the final stage. Both stages, the character and the short animated film, were developed with the predicted findings of the theoretical investigation in mind. The findings presented in this paper validate our dimensional model showing that, indeed, the credibility of the animation of a virtual character responds to new prerogatives that are constantly becoming more deeply rooted in art and the creative industries