User-space Multipath UDP in Mosh

In many network topologies, hosts have multiple IP addresses, and may choose among multiple network paths by selecting the source and destination addresses of the packets that they send. This can happen with multihomed hosts (hosts connected to multiple networks), or in multihomed networks using source-specific routing. A number of efforts have been made to dynamically choose between multiple addresses in order to improve the reliability or the performance of network applications, at the network layer, as in Shim6, or at the transport layer, as in MPTCP. In this paper, we describe our experience of implementing dynamic address selection at the application layer within the Mobile Shell. While our work is specific to Mosh, we hope that it is generic enough to serve as a basis for designing UDP-based multipath applications or even more general APIs

CPC: programming with a massive number of lightweight threads

Threads are a convenient and modular abstraction for writing concurrent programs, but often fairly expensive. The standard alternative to threads, event-loop programming, allows much lighter units of concurrency, but leads to code that is difficult to write and even harder to understand. Continuation Passing C (CPC) is a translator that converts a program written in threaded style into a program written with events and native system threads, at the programmer's choice. Together with two undergraduate students, we taught ourselves how to program in CPC by writing Hekate, a massively concurrent network server designed to efficiently handle tens of thousands of simultaneously connected peers. In this paper, we describe a number of programming idioms that we learnt while writing Hekate; while some of these idioms are specific to CPC, many should be applicable to other programming systems with sufficiently cheap threads.Comment: To appear in PLACES'1

Lambda-lifting and CPS conversion in an imperative language

This paper is a companion technical report to the article "Continuation-Passing C: from threads to events through continuations". It contains the complete version of the proofs of correctness of lambda-lifting and CPS-conversion presented in the article.Comment: arXiv admin note: substantial text overlap with arXiv:1011.455

Source-specific routing

Source-specific routing (not to be confused with source routing) is a routing technique where routing decisions depend on both the source and the destination address of a packet. Source-specific routing solves some difficult problems related to multihoming, notably in edge networks, and is therefore a useful addition to the multihoming toolbox. In this paper, we describe the semantics of source-specific packet forwarding, and describe the design and implementation of a source-specific extension to the Babel routing protocol as well as its implementation - to our knowledge, the first complete implementation of a source-specific dynamic routing protocol, including a disambiguation algorithm that makes our implementation work over widely available networking APIs. We further discuss interoperability between ordinary next-hop and source-specific dynamic routing protocols. Our implementation has seen a moderate amount of deployment, notably as a testbed for the IETF Homenet working group

Non-Arrhenius conduction due to the interface-trap-induced disorder in X-doped amorphous InXZnO thin-film transistors

Thin film transistors, with channels composed of In-X-Zn oxides, IXZO, with X dopants: Ga, Sb, Be, Mg, Ag, Ca, Al, Ni, and Cu, were fabricated and their I-V characteristics were taken at selected temperatures in the 77K<T<300K range. The low field mobility, mu, and the interface defect density, Nst were extracted from the characteristics for each of the studied IXZOs. At higher T the mobility follows the Arrhenius law with an upward distortion, increasing as T was lowered, gradually transforming into the exp [-(T0/T)1/4] variation. We showed that mu(T, Nst) follows mu0exp[-Eaeff(T,Nst)/kT], with T-dependent effective activation energy Eaeff(T, Nst) accounts for the data, revealing a linear correlation between Eaeff and Nst at higher T. Temperature variation of Eaeff(T, Nst) was evaluated using a model assuming a random distribution of conduction mobility edge Ec values in the oxides, stemming from spatial fluctuations induced by disorder in the interface traps distribution. For a Gaussian distribution of Ec, the activation energy Eaeff(T, Nst) varies linearly with 1/T, which accounts satisfactorily for the data obtained on all the studied IXZOs. The model also shows that Eaeff(T, Nst) is a linear function of Nst at a fixed T, which explains the exponential decrease of mu with NST

Vector Based 2D Drawing Program

Tato práce řeší problematiku vektorové počítačové grafiky a její tvorby. Na začátku je uveden stručný přehled dostupných softwarových nástrojů s příklady oblastí jejich typického použití. Následuje popis vektorových 2D grafických editorů na které se práce primárně zaměřuje. Popsáno je typické uživatelské rozhraní takovýchto programů doplněné popisem základní funkčnosti a vlastností těchto aplikací. Po teoretické části následuje popis návrhu vlastního vektorového 2D kreslícího programu včetně jeho implementace, použitých nástrojů a klíčových technologií. Nakonec je zde obsaženo zhodnocení dosažených výsledků s vyhodnocením směřování projektu do budoucna.This thesis solves the issue of vector computer graphics and its creation. At the beginning there is a brief overview of available software tools with examples of typical application areas. It is followed by a description of 2D vector graphics editors, which are the primary focus. Described is a typical user interface of such programs, together with a description of the basic features and functionality of these applications. After the theoretical part is followed by the design our own vector based 2D drawing program, including its implementation, the tools and core technologies. Finally, there is included an evaluation of the results, assessing the future directions of the project.

BitTorrent DHT Extensions for IPv6

BEP-32This document describes a set of extensions to the BitTorrent DHT to allow operation over IPv6.Ce document décrit les extensions à la table de hachage distribuée de BitTorrent pour lui permettre de fonctionner au-dessus d'IPv6

Impact of dopant species on the interfacial trap density and mobility in amorphous In-X-Zn-O solution-processed thin-film transistors

Alloying of In/Zn oxides with various X atoms stabilizes the IXZO structures but generates electron traps in the compounds, degrading the electron mobility. To assess whether the latter is linked to the oxygen affinity or the ionic radius, of the X element, several IXZO samples are synthesized by the sol-gel process, with a large number (14) of X elements. The IXZOs are characterized by XPS, SIMS, DRX, and UV-spectroscopy and used for fabricating thin film transistors. Channel mobility and the interface defect density NST, extracted from the TFT electrical characteristics and low frequency noise, followed an increasing trend and the values of mobility and NST are linked by an exponential relation. The highest mobility (8.5 cm2/Vs) is obtained in In-Ga-Zn-O, and slightly lower value for Sb and Sn-doped IXZOs, with NST is about 2E12 cm2/eV, close to that of the In-Zn-O reference TFT. This is explained by a higher electronegativity of Ga, Sb, and Sn than Zn and In, their ionic radius values being close to that of In and Zn. Consequently, Ga, Sb, and Sn induce weaker perturbations of In-O and Zn-O sequences in the sol-gel process, than the X elements having lower electronegativity and different ionic radius. The TFTs with X = Ca, Al, Ni and Cu exhibited the lowest mobility and NST > 1E13 cm2/eV, most likely because of metallic or oxide clusters formation

Assessing the Financial Situation of a Company Using Time Series Analysis

Diplomová práce se zabývá zhodnocením finanční situace vybraného e-shopu spotřební elektroniky s názvem czc.cz. Pro toto zhodnocení se použije analýza časových řad, díky které bude možno predikovat budoucí vývoj vybraných ukazatelů. Na základě vývoje ukazatelů bude tento e-shop srovnán s konkurencí. Pomoci této analýzy budou navrženy možnosti ke zlepšení finanční situace e-shopu.This master thesis evaluates the financial situation of the selected e-shop of consumer electronics called czc.cz. For this evaluation, it will be used time series analysis, through which it will be possible to predict the future development of selected indicators. Based on the development of these indicators, e-shop will be compared with the competitors. Through this analysis there will be proposed options to improve the financial situation of the e-shop.