Cyclone Codes

We introduce Cyclone codes which are rateless erasure resilient codes. They combine Pair codes with Luby Transform (LT) codes by computing a code symbol from a random set of data symbols using bitwise XOR and cyclic shift operations. The number of data symbols is chosen according to the Robust Soliton distribution. XOR and cyclic shift operations establish a unitary commutative ring if data symbols have a length of $p-1$ bits, for some prime number $p$. We consider the graph given by code symbols combining two data symbols. If $n/2$ such random pairs are given for $n$ data symbols, then a giant component appears, which can be resolved in linear time. We can extend Cyclone codes to data symbols of arbitrary even length, provided the Goldbach conjecture holds. Applying results for this giant component, it follows that Cyclone codes have the same encoding and decoding time complexity as LT codes, while the overhead is upper-bounded by those of LT codes. Simulations indicate that Cyclone codes significantly decreases the overhead of extra coding symbols

Tax Reform in the Slovak Republic

Steuerreform, Slowakei,Tax Reform, Slovakia

Effect-specific analysis of propagation parameters

Results of propagation measurements with the satellite OLYMPUS carried out at 12.5, 20, and 30 GHz at the Research Center of the Deutsche Bundespost Telekom are discussed. In particular, attenuation, scintillation, and depolarization measurements are analyzed with special emphasis on frequency scaling of the various effects

Die gesellschaftliche Verteilung von Traurigkeit. Eine emotionssoziologische Analyse

Zusammenfassung: Die Soziologie interessiert sich für die soziale Verteilung und Determinanten von Traurigkeit als Teil der Gefühlskultur einer Gesellschaft. Sie eröffnet zugleich Potenziale für das Themenfeld der sozialen Ungleichheit von Emotionen. Auf der Grundlage einer Querschnittsanalyse von Daten des Schweizer Haushalt-Panels (SHP) werden Zusammenhänge zwischen der Häufigkeit der erlebten Traurigkeit und Merkmalen der sozialstrukturellen Position, des sozialen Kontextes sowie in Abhängigkeit von kritischen Lebensereignissen geprüft. Der Beitrag bestätigt Variationen von Traurigkeit entlang sozialer Merkmale wie Geschlecht, Einkommen, Alter, Nationalität und Sprachregio

A recipe for the crystallization of enzymes

A recipe for the crystallization of enzyme

Computing Shortest Paths in Series-Parallel Graphs in Logarithmic Space

Series-parallel graphs, which are built by repeatedly applying series or parallel composition operations to paths, play an important role in computer science as they model the flow of information in many types of programs. For directed series-parallel graphs, we study the problem of finding a shortest path between two given vertices. Our main result is that we can find such a path in logarithmic space, which shows that the distance problem for series-parallel graphs is L-complete. Previously, it was known that one can compute some path in logarithmic space; but for other graph types, like undirected graphs or tournament graphs, constructing some path between given vertices is possible in logarithmic space while constructing a shortest path is NL-complete