Fountain codes are record-breaking sparse-graph codes for channels with erasures, such as the internet, where files are transmitted in multiple small packets, each of which is either received without error or not received. Standard file transfer protocols simply chop a file up into K packetsized pieces, then repeatedly transmit each packet until it is successfully received. A back channel is re...

The uncertainty evaluation of CSF2, the second caesium fountain primary frequency standard at PTB, is presented. The fountain uses optical molasses to cool atoms down to 0.6μK. The atoms are launched vertically in a moving optical molasses, and state-selected in the |F = 3,mF = 0〉 hyperfine ground state. During their ballistic flight, the atoms interact twice with a microwave field, thus comple...

A novel concept of joint source-fountain coding for asynchronous wireless broadcast is presented. The traditional field of joint source-channel coding aims in both lossless data compression as well as reliable data delivery. Besides, fountain coding allows reliable broadcast without the need of feedback, and furthermore, asynchronous data access, i.e., each receiver is able to decide when it wa...

In this paper we consider the joint performance of fountain codes and 802.11a/g PHY modulation/coding. We consider optimality both in terms of maximizing goodput and minimizing energy, and results are presented for both theoretical and experimental channel models. In contrast to studies in cellular networks, we find that in 802.11a/g WLANs the cross-layer approach of a higher-layer fountain cod...

Fountain codes are becoming increasingly important for data transferring over dedicated high-speed long-distance network. However, the encoding and decoding complexity of traditional fountain codes such as LT and Raptor codes are still high. In this paper, a new fountain codes named LRF (Loss Rate Based Fountain) codes for data transfer is proposed. In order to improve the performance of encodi...

The influence of pH, conductivity and Ca ion concentrations of fountain solutions on the quality of tone, dot, line and text was investigated. Physico-chemical parameters of fountain solutions were analyzed by standard methods. Image quality assessment (IQA) was carried out using the ISO methodology and ImageJ software. The obtained data of the mechanical and optical tone value, dot circularity...

We present the first measurements of radiance spectra of rainbows. The bows on two sunny days (3 and 6 June 2008) were produced by the fountain in the Parque de las Ciencias, Granada, Spain, that consists of a rectangular perimeter of 40 spray nozzles. Optical thickness of the spray from each nozzle was approximately 0.5. Spectral purity of the primary bow was highest for orange and blue, reach...

Over the past decade, rateless codes, i.e., digital fountain codes, have emerged as an efficient and robust solution for reliable data transmission over packet erasure networks and a particularly suitable one for multicasting and broadcasting applications where users may experience variable channel conditions and packet loss rates, such as mobile environments. Luby Transform (LT) and Raptor cod...

Gas that escapes from the Galactic disk, rises into the halo, cools and falls back, constitutes a “Galactic fountain”. Three-dimensional simulations show that such a fountain model reproduces many of the features that have been observed in the Galaxy and other galaxies such as M31 and M33. Here, these results are reported.