Crowdsourced Live Streaming over the Cloud

Empowered by today's rich tools for media generation and distribution, and the convenient Internet access, crowdsourced streaming generalizes the single-source streaming paradigm by including massive contributors for a video channel. It calls a joint optimization along the path from crowdsourcers, through streaming servers, to the end-users to minimize the overall latency. The dynamics of the video sources, together with the globalized request demands and the high computation demand from each sourcer, make crowdsourced live streaming challenging even with powerful support from modern cloud computing. In this paper, we present a generic framework that facilitates a cost-effective cloud service for crowdsourced live streaming. Through adaptively leasing, the cloud servers can be provisioned in a fine granularity to accommodate geo-distributed video crowdsourcers. We present an optimal solution to deal with service migration among cloud instances of diverse lease prices. It also addresses the location impact to the streaming quality. To understand the performance of the proposed strategies in the realworld, we have built a prototype system running over the planetlab and the Amazon/Microsoft Cloud. Our extensive experiments demonstrate that the effectiveness of our solution in terms of deployment cost and streaming quality

Qualitative model of a positive hydrogen peroxide ion in a thermal bath

A qualitative model is proposed for a pair of atoms: oxygen and hydrogen in a single-mode optical cavity, bound by one valence electron and immersed in a thermal bath. The interaction of an electron with the cavity field depends on the state of the nuclei, which, in turn, is determined by the temperature of the phonon mode of the thermal bath. Computer simulation of the quantum dynamics of such a system shows the stable nature of the formation of both a stable molecular ion and a separate neutral oxygen atom and a positive hydrogen ion.Comment: 11 pages, 5 figure

Collapse of dark states in Tavis-Cummings model

The singlet state of a system of two two-level atoms changes smoothly, remaining dark, as the Hamiltonian TC is slowly deformed, despite the inapplicability of the adiabatic theorem to this case. In this case, there is a small probability of emission of free photons, which does not depend on the smoothness of the deformation of the Hamiltonian. The effect of spontaneous emission is enhanced by the addition of one more pair of atoms in the singlet state due to the exchange of virtual photons in the cavity. A similar effect was also established for the case when atoms can move between two cavities, but here, on the contrary, with an increase in the number of atoms, the emission decreases. This purely quantum effect must be taken into account in practical manipulations with atomic singlets; however, its weakness testifies, rather, to the stability of dark states and the prospects for their use in information exchange (quantum cryptographic protocols) and as an energy accumulator for nono-devices.Comment: 16 pages, 14 figure

Cooperative Coding and Caching for Streaming Data in Multihop Wireless Networks

This paper studies the distributed caching managements for the current flourish of the streaming applications inmultihop wirelessnetworks. Many caching managements to date use randomized network coding approach, which provides an elegant solution forubiquitous data accesses in such systems. However, the encoding, essentially a combination operation, makes the coded datadifficult to be changed. In particular, to accommodate new data, the system may have to first decode all the combined datasegments, remove some unimportant ones, and then reencode the data segments again. This procedure is clearly expensivefor continuously evolving data storage. As such, we introduce a novel Cooperative Coding and Caching (C3) scheme, whichallows decoding-free data removal through a triangle-like codeword organization. Its decoding performance is very close to theconventional network coding with only a sublinear overhead. Our scheme offers a promising solution to the caching managementfor streaming data

Network Characteristics of LEO Satellite Constellations: A Starlink-Based Measurement from End Users

Low Earth orbit Satellite Networks (LSNs) have been advocated as a key infrastructure for truly global coverage in the forthcoming 6G. This paper presents our initial measurement results and observations on the end-to-end network characteristics of Starlink, arguably the largest LSN constellation to date. Our findings confirm that LSNs are a promising solution towards ubiquitous Internet coverage over the Earth; yet, we also find that the users of Starlink experience much more dynamics in throughput and latency than terrestrial network users, and even frequent outages. Its user experiences are heavily affected by environmental factors such as terrain, solar storms, rain, clouds, and temperature, so is the power consumption. We further analyze Starlink's current bent-pipe relay strategy and its limits, particularly for cross-ocean routes. We have also explored its mobility and portability potentials, and extended our experiments from urban cities to wild remote areas that are facing distinct practical and cultural challenges.Comment: 12 pages, 20 figures, to be published in IEEE INFOCOM 202

Collaborative view synthesis for interactive multi-view video streaming

Interactive multi-view video enables users to enjoy the video from different viewpoints. Yet multi-view dramatically in-creases the video data volume and their computation, mak-ing realtime transmission and interactions a challenging task. It therefore calls for efficient view synthesis strategies that flexibly generate visual views. In this paper, we present a collaborative view synthesis strategy for online interactive multi-view video streaming based on Depth-Image Based Rendering (DIBR) view synthesis technology, which gener-ates a visual view with the texture and depth information on both sides. Different from the traditional DIBR algorithm for single view synthesis, we explore the collaboration rela-tionship between different viewpoints synthesis for a range of visual views generation, and propose Shift DIBR (S-DIBR). In S-DIBR, only the projected pixels, rather than all the pixels of the reference view, are utilized for next visual view generation. Therefore, the computation complexity of pro-jection transform, which is the most computation intensive process in the traditional DIBR algorithm, is reduced to fulfill the requirement of online interactive streaming. Ex-periment results validate the efficiency of our collaborative view synthesis strategy, as well as the bandwidth scalability of the streaming system

Recent charmonium results from BES

Using 58 million J/ψ decays, we have investigated the $p \bar{p}$ invariant mass spectrum in the radiative decay $J/\psi \rightarrow \gamma p \bar{p}$ and observe a prominent structure with mass near 2m p . Fitting with an S-wave Breit-Wigner, we obtain a peak mass of M= 1859+3 –10(stat)+5 –25(sys) MeV/c2. J/ψ → γ η c decays from the same sample are used to determine the mass, width, and hadronic branching ratios of the η c . From a sample of 14 million ψ(2S) events, the first observation of χ cJ (J=0,1,2) decays to $\Lambda\overline{\Lambda}$ is made, and branching ratios are determined, which are larger than expected from the Color Octet Model. Branching ratios of K s 0 K L 0 in both ψ(2S) and J/ψ decays are measured, and a more than four sigma deviation from the pQCD-predicted ”12% rule” is observed. In ψ(3770) decays, evidence for the non-$D\bar{D}$ decay to π + π – J/ψ is observed. PACS: 13.20.Gd Decays of J/psi, Upsilon, and other quarkoni