CliqueStream: an efficient and fault-resilient live streaming network on a clustered peer-to-peer overlay

Several overlay-based live multimedia streaming platforms have been proposed in the recent peer-to-peer streaming literature. In most of the cases, the overlay neighbors are chosen randomly for robustness of the overlay. However, this causes nodes that are distant in terms of proximity in the underlying physical network to become neighbors, and thus data travels unnecessary distances before reaching the destination. For efficiency of bulk data transmission like multimedia streaming, the overlay neighborhood should resemble the proximity in the underlying network. In this paper, we exploit the proximity and redundancy properties of a recently proposed clique-based clustered overlay network, named eQuus, to build efficient as well as robust overlays for multimedia stream dissemination. To combine the efficiency of content pushing over tree structured overlays and the robustness of data-driven mesh overlays, higher capacity stable nodes are organized in tree structure to carry the long haul traffic and less stable nodes with intermittent presence are organized in localized meshes. The overlay construction and fault-recovery procedures are explained in details. Simulation study demonstrates the good locality properties of the platform. The outage time and control overhead induced by the failure recovery mechanism are minimal as demonstrated by the analysis.Comment: 10 page

Para uma formação actualizada

Na formação do jovem músico do século XXI, ainda há pouca abordagem da música do último século. Com este texto pretendo contribuir para a compreensão desta música, na esperança de que ela seja utilizada cada vez mais como parte central da formação do jovem músico. Neste texto, fala-se do funcionamento do ritmo

Non-serial criteria in the pitch organization of Webern´s twelve-note works

This article shows how the intervals produced by specific realizations of the row can define the musical character more than the mere use of the row itself. Examples are drawn from the Concerto Op.24

Cities On Hills: Seeking the Holy Land

Cities On Hills: Seeking the Holy Land is a collection of thirty-two vignettes and poems that chronicle a month-long cultural exploration and archaeological dig in Israel/Palestine in 2000, the year before 9/11. The stories are told by a narrator ten years after her journey, reflecting back on her nineteen-year-old self and the impact the experience had on her world view and personal beliefs. The Holy Land itself is a vital character, informing and influencing the behaviors of the narrator and her dig team. Places in and around Jerusalem, Galilee, Bethlehem, as well as moments in Jordan, are pieced together like a loosely-structured photo album, functioning as a whole to offer a glimpse into a culture that many Americans are now reluctant to experience in a post-9/11 mindset. Thematically, the stories and poems essentially revolve around seeking beauty and truth amidst violence and turmoil of the legendary, historic, and modern Holy Land, from the perspective of a rebellious outsider who desperately wants to be an insider. What constitutes historical truth versus myth? What part does rebellion play in seeking truth? The three parts--Jerusalem, Galilee, and Bethlehem--loosely trace the footsteps of Jesus Christ from resurrection to birth, metaphorical for the narrator\u27s need to dig past the fairytales of her childhood and uncover their origins. For the most part, the narrator realizes that truth must be investigated and actively sought by the individual--that it is, in fact, her responsibility to do so. The collection ends with a coming-of-age birthday party. Like the narrator\u27s loss of her safety net, the naivety of the nameless American tourist is about to be wiped away in a year\u27s time, with the bombing of the World Trade Center and Pentagon. Eyes opened, she must now learn to live in a bigger, more brutal, more beautiful world. It should be noted that this travel memoir is a work in progress. Future stories include two or three additional rebellion stories in Galilee that highlight other aspects of that region, and several stories in Bethlehem, including visiting Dar Al-Kalima Academy, examples of some of the violence that has since taken place, and touring the tombs beneath the Church of the Nativity--the location of the 2002 siege

Radical-initiated alkene hydroauration as a route to gold(III) alkyls: an experimental and computational study

The hydroauration of functionalised 1-alkenes by the gold(III) hydride (C^NOMe^C)AuH is initiated by organic radicals and proceeds via (C^N^C)Au(II) radical intermediates following a bimolecular outer-sphere mechanism. The outcome of these reactions is determined by the stability of the gold-substituted radicals. The reaction is sensitive to steric as well as electronic factors; disubstituted alkenes and alkenes that form unstable radicals give product mixtures or are unreactive. As DFT calculations show, the reactions agree well with the calculated reaction enthalpies and the standard free energy change for the reaction of the gold(II) radical with the respective alkene

Criteria for graphic representation in musical scores: Visual elements in musical scores

A interdisciplinaridade entre a música e as artes visuais tem sido explorado por conceituados teóricos e filósofos, embora não exista muito na área da interpretação visual do grafismo de partituras musicais. Este estudo investiga como os grafismos na notação e símbolos musicais afectam o intérprete na sua transformação em som, com referência especial a partituras contemporâneas, que utilizam notação menos convencional para a criação de uma interpretação por sugestão. Outras relações entre o som e o visual são exploradas, incluindo a sinestesia, a temporalidade e a relação entre obra de arte e público. O objectivo desta dissertação é a de constituir um estudo inovativo sobre partituras musicais contemporâneas, simultaneamente do ponto de vista musical e visual. Finalmente, também vai mais longe, incluindo desenhos da própria autora inspirados e motivados pela música. Estes já não cumprem uma função de notação convencional para o músico, embora existe uma constante possibilidade de uma reinterpretação. ABSTRACT; The inter-disciplinarity between music and visual art has been explored by leading theorists and philosophers, though very little exists in the area of the visual interpretation of graphic musical scores. This study looks at how the graphics of musical notation and symbols affect the performer in transforming them into sound, with particular reference to contemporary scores that use non¬conventional notation to create an interpretation through suggestion. Other sound-visual relationships are explored, including synaesthesia, temporality and the interconnection between work of art and audience or public. This dissertation aims to be an innovative study of contemporary musical scores, from a musical as well as visual perspective. Finally, it takes a step further with drawings of my own, directly inspired and motivated by the music. These no longer fulfil a conventionally notational function for the musician, yet the potential for a re-interpretation is ever-present

Lossless State Detection of Single Neutral Atoms

We introduce lossless state detection of trapped neutral atoms based on cavity-enhanced fluorescence. In an experiment with a single 87-Rb atom, a hyperfine-state-detection fidelity of 99.4% is achieved in 85 microseconds. The quantum bit is interrogated many hundreds of times without loss of the atom while a result is obtained in every readout attempt. The fidelity proves robust against atomic frequency shifts induced by the trapping potential. Our scheme does not require strong coupling between the atom and cavity and can be generalized to other systems with an optically accessible quantum bit.Comment: 4 pages, 4 figure

Photochemical Disproportionation of an Au(II) Pincer Complex:Synthesis and Structure of an Au(I)4Au(III)4 Macrocycle

The Au(II) C^N^C pincer complex [(C^N^C)Au]2 is stable under thermal conditions but disproportionates on irradiation in solution to give an Au(I)4Au(III)4 mixed-valence aggregate with a 20-membered macrocyclic structure, consisting of four linear Au(I) C-Au-N building blocks, each of which is decorated with a square planar (C^N^C)Au(III) substituent. In the crystal, the rings are stacked to form solvent-filled channels with an internal diameter of 8.3 Å and a cross-channel AuIAuI distance of 7.7 Å