T-folds as Poisson-Lie plurals

In previous papers we have presented many purely bosonic solutions of Generalized Supergravity Equations obtained by Poisson-Lie T-duality and plurality of flat and Bianchi cosmologies. In this paper we focus on their compactifications and identify solutions that can be interpreted as T-folds. To recognize T-folds we adopt the language of Double Field Theory and discuss how Poisson-Lie T-duality/plurality fits into this framework. As a special case we confirm that all non-Abelian T-duals can be compactified as T-folds.Comment: v3 - published versio

Algorithms for High-Speed Routing in IP Networks

Práce se zabývá simulací algoritmů vyhledávajících v IP sítích nejdelší shodný prefix, konkrétně Trie, Tree Bitmap a Shape Shifting Trie. Algoritmy jsou implementovány softwarově a je zkoumána jejich paměťová a výpočetní náročnost.This work deals with simulation of algorithms finding the longest matching prefix in IP networks, particularly Trie, Tree Bitmap and Shape Shifting Trie. Algorithms are software implemented and explored about their memory and computational performance.

Poisson-Lie transformations and Generalized Supergravity Equations

In this paper we investigate Poisson-Lie transformation of dilaton and vector field J appearing in Generalized Supergravity Equations. While the formulas appearing in literature work well for isometric sigma models, we present examples for which Generalized Supergravity Equations are not preserved. Therefore, we suggest modification of these formulas.Comment: published versio

Vliv geometrie pájeného spoje na jeho mechanické vlastnosti

This paper deals with influence of soldered joint geometry on measurement of its mechanical properties. Mechanical properties of soldered lap-joints of four lead-free solders with different geom-etry were measured. In conclusion using of samples with one interface solder – soldered material for measurement of soldered joints mechanical properties is recommended.Příspěvek se zabývá vlivem tvaru geometrie pájeného spoje na jeho mechanické vlastnosti. Byly naměřené mechanické vlastnosti přeplátovaných spojů čtyř bezolovnatých pájek S různou geo-metrií spojů vzorků. V závěru je doporučeno měření mechanických vlastností pájených spojů pouţi-tých vzorků S jedním rozhraním pájka – pájený materiál

Network Protection Using NetFlow Data

Dokument se zabývá studií technologie NetFlow od společnosti Cisco a jejím možném využití při monitorování datových sítí a detekci síťových anomálií. Na základě analýzy útoků na síťové a transportní vrstvě je navržena pro vybrané bezpečnostní hrozby aplikace detekující jejich výskyt. Implementační část obsahuje také systém pro predikci provozu na síti a s tím související detekování odchylek od standardního chování na základě statistických údajů. Využití technologie Netflow je demonstrováno na příkladech, kde by výsledky ostatních současných bezpečnostních a monitorovací technik selhaly, případně nepodaly dostatečně kvalitní výsledky. This document focuses on Cisco Netflow technology and its possible usage in monitoring networks and detecting network anomalies. Based on the analysis of attacks at the network and transport layer is designed an application for selected security threats which detects its presence. The implementation section provides a system for predicting network traffic and related detecting deviations from the baseline on the basis of statistical data. Use of NetFlow technolgy is demonstrated on examples where the results of other current security and monitoring techniques have failed or did not provide sufficiently good results.

Zavarljivost čelika s visokim udjelom mangana

Nowadays one of the most important parts, which are used in railway industry, are crossings, and principally the dynamic component of the operation exposures. A Mangalloy, also called as manganese steel or Hadfield steel, is a steel with alloys containing an average 13 % of manganese and is unique for the reason that it combines high toughness and ductility with great work-hardening capacity. The wear resistance before the contact wear depends on the level of the surface hardening intensity, and the hardening process during operation consequently [1, 2, 3]. As abrasion resistance is proper to increase the carbon level above 1,4 % and moreover, it could cause a problem in obtaining a homogenous austenitic structure which would be sufficiently free of carbide bordered grains [4].Jedan od najvažnijih dijelova koji se danas koriste na željeznici su dijelovi na cestovnim prijelazima preko pruge i uglavnom dinamička komponenta izložena djelovanju. Mangalloy, također poznat kao čelik s manganom ili Hadfield čelik, je čelik s legurama koje u prosjeku sadrže 13 % mangana i jedinstven je po tome što povezuje visoku žilavost i duktilnost s velikom sposobnošću radnog otvrdnjivanja. Otpornost na trošenje prije kontaktnog trošenja ovisi o intenzitetu otvrdnjavanja površine i postupku otvrdnjavanja tijekom rada [1, 2, 3,]. Budući da se zbog otpornosti abraziji povećava postotak ugljika iznad 1,4 % i više, može se pojaviti problem postizanja homogene austenitne strukture koja bi bila bez zrnaca karbida [4].Web of Science23375274

The repair of foundry defects in steel castings using welding technology

Use of welding technology for the repair of steel castings is particularly common in two areas. These include weld surfacing of protrusions that remained incomplete after casting, or filling the surface defects (cavities). These defects are more common for steel casting than for graphite cast iron, due to the lower fluidity of steel. This article describes a suitable technological process of repairing the defects on the casting using the welding technology. A specimen produced for this purpose was prepared by carving a groove into a cast steel plate 20 GL, which was then filled with a weld metal using MAG (135) technology. The following evaluation of the basic characteristics of the repaired site point to the suitability of the selected technological parameters of the repair procedure. Metallographic evaluation was carried out, further evaluation of mechanical properties by tensile test, bend test and Vickers hardness test. The proposed methodology for the evaluation repair of foundry defects in steel castings also meets the requirements for the approval of welding procedures in accordance with the relevant valid legislation.Web of Science18218017

Racionalizacija toka materijala u proizvodnji polu-okvira za automobilsku industriju

The core idea of the paper is a value stream mapping with identification of waste sources, and drawbacks which help to uncover hidden reserves of production. The analysis covers the current state of individual processes within the production line. After determination of the present drawbacks the plan of rationalization was created in which the combination of elements of lean production was used. The proposed solutions could be used when establishing the principles of lean production at particular sections of the assembly line within the whole plant. In case that proposed solution cannot be put into practice it can be used as a blueprint for other types of improvement respectively decreasing of waste and drawbacks.Osnovna ideja rada je prikaz toka vrijednosti uz identifikaciju izvora troškova i nedostataka, koji će pomoći da se razotkriju skrivene pričuve u proizvodnji. Analiza obuhvaća postojeće stanje u pojedinačnim postupcima na proizvodnoj traci. Nakon prepoznavanja postojećih nedostataka napravljen je plan racionalizacije u kojemu je rabljena kombinacija elemenata lean proizvodnje. Predložena bi se rješenja mogla primijeniti kad se primijene principi lean proizvodnje na pojedinim dijelovima montažne trake u cijelom pogonu. U slučaju da se predloženo rješenje ne može primijeniti u praksi može se koristiti kao model za druge vrste poboljšanja kao što su smanjenje otpada i nedostataka.Web of Science2341220121

Návrh efektívneho spôsobu merania rozmerov na princípe inerciálneho meracieho systému

The work presents automated methods of dimensions measurement, extending the known horizont of used approach to measuring by the draft of a new unused method. a method described in the paper is based on the principle of self-localization of inertial sensors that are able to describe the actual value of angular velocity and acceleration in the direction of each coordinate axis. Prerequisite accuracy of these measurements is a clear definition of zero position in space and taking into account a wide range of ambient effects. The method should allows to measure dimensions of objects of complex shape with high accuracy even in places where usage of conventional methods is not always possible. The contribution also describes principles of inertial navigation systems and MEMS technology, which significantly reduces the cost of mentioned advanced technologies.Práca približuje problematiku automatizovaných metód merania rozmerov, pričom rozširuje doteraz známy obzor používaných prístupov K meraniam O návrh novej, doteraz nepoužívanej, metódy. V práci popisovaný spôsob merania rozmerov vychádza Z princípu vlastnej lokalizácie inerciálnych senzorov, schopných popisovať aktuálne hodnoty uhlových rýchlostí a zrýchlení V smere jednotlivých súradnicových osí priestoru. Nutným predpokladom presnosti týchto meraní je jasná definícia nulovej polohy systému V priestore a zohľadnenie širšieho spektra vplyvov okolia. Metóda by mohla umožniť meranie rozmerov tvarovo zložitých objektov S vysokou presnosťou, a to dokonca aj na miestach, kde by to pri použití konvenčných metód meraní nemuselo byť vždy možné. Príspevok taktiež informačne popisuje princípy funkcie inerciálnych navigačných systémov a technológie MEMS, ktorá značne znižuje náklady na použitie týchto pokrokových technológií