On Frequency LTL in Probabilistic Systems

We study frequency linear-time temporal logic (fLTL) which extends the linear-time temporal logic (LTL) with a path operator $G^p$ expressing that on a path, certain formula holds with at least a given frequency p, thus relaxing the semantics of the usual G operator of LTL. Such logic is particularly useful in probabilistic systems, where some undesirable events such as random failures may occur and are acceptable if they are rare enough. Frequency-related extensions of LTL have been previously studied by several authors, where mostly the logic is equipped with an extended "until" and "globally" operator, leading to undecidability of most interesting problems. For the variant we study, we are able to establish fundamental decidability results. We show that for Markov chains, the problem of computing the probability with which a given fLTL formula holds has the same complexity as the analogous problem for LTL. We also show that for Markov decision processes the problem becomes more delicate, but when restricting the frequency bound $p$ to be 1 and negations not to be outside any $G^p$ operator, we can compute the maximum probability of satisfying the fLTL formula. This can be again performed with the same time complexity as for the ordinary LTL formulas.Comment: A paper presented at CONCUR 2015, with appendi

Probabilistic Bisimulations for PCTL Model Checking of Interval MDPs

Verification of PCTL properties of MDPs with convex uncertainties has been investigated recently by Puggelli et al. However, model checking algorithms typically suffer from state space explosion. In this paper, we address probabilistic bisimulation to reduce the size of such an MDPs while preserving PCTL properties it satisfies. We discuss different interpretations of uncertainty in the models which are studied in the literature and that result in two different definitions of bisimulations. We give algorithms to compute the quotients of these bisimulations in time polynomial in the size of the model and exponential in the uncertain branching. Finally, we show by a case study that large models in practice can have small branching and that a substantial state space reduction can be achieved by our approach.Comment: In Proceedings SynCoP 2014, arXiv:1403.784

Půjčování e-knih : srovnání situace v ČR, USA a SRN

Snahy o půjčování nebo jiné formy zpřístupňování elektronických knih v knihovnách probíhají souběžně u nás i v zahraničí. Cílem příspěvku je poskytnout srovnání situace v České republice se zahraničím a prezentovat nejznámější zahraniční služby použitelné nebo již využívané (nejen) v knihovnách. Příspěvek popisuje německé služby Onleihe, Skoobe a PaperC a americká spolupráce mezi Amazonem a společností Overdrive.Snahy o půjčování nebo jiné formy zpřístupňování elektronických knih v knihovnách probíhají souběžně u nás i v zahraničí. Cílem příspěvku je poskytnout srovnání situace v České republice se zahraničím a prezentovat nejznámější zahraniční služby použitelné nebo již využívané (nejen) v knihovnách. Příspěvek popisuje německé služby Onleihe, Skoobe a PaperC a americká spolupráce mezi Amazonem a společností Overdrive.Efforts to borrowing e-books to users are evident in the Czech Republic as well as in other countries. The aim of this paper is to provide a comparison of the situation in the Czech Republic with foreign countries and to present the some services already used (not only) in libraries. This paper describes the German services Onleihe, Skoobe and PaperC and cooperation between American companies Amazon and Overdrive

The Fortification of the polis Milet and its development from the Bronze Age into the late Antiquity.

(in English): The aim of this bachelor thesis is to introduce the individual phases of the fortification in the history of Miletus, chronologically from the Late Bronze Age to the Late Antiquity. For each period, the historical context and the development of the topography of the city will be briefly presented, followed by an analysis of the fortification of the period and a description of some examples based on archaeological sources. In the final part each described period of the fortifications of Miletus will be classified into the historical context of Ionia and compared with the selected poleis of the region.(česky) Bakalářská práce má za cíl představit jednotlivé fáze opevnění v historii Milétu, a to chronologicky od pozdní doby bronzové až po pozdní antiku. pro každé období bude stručně uveden historický kontext a vývoj topografie města, a následně na základě archeologických zdrojů provedena analýza opevnění daného období a popis příkladů. Ve finální části bude opevnění Milétu pro každé popisované období zařazeno do historického kontextu Iónie a porovnáno s vybranými poleis regionu.Ústav pro klasickou archeologiiInstitute for Classical ArcheologyFaculty of ArtsFilozofická fakult

Mastering operational limitations of LEO satellites – The GOMX-3 approach

When working with space systems the keyword is resources. For a satellite in orbit all resources are sparse and the most critical resource of all is power. It is therefore crucial to have detailed knowledge on how much power is available for an energy harvesting satellite in orbit at every time – especially when in eclipse, where it draws its power from onboard batteries. This paper addresses this problem by a two-step procedure to perform task scheduling for low-earth-orbit (LEO) satellites exploiting formal methods. It combines cost-optimal reachability analyses of priced timed automata networks with a realistic kinetic battery model capable of capturing capacity limits as well as stochastic fluctuations. The procedure is in use for the automatic and resource-optimal day-ahead scheduling of GOMX-3, a power-hungry nanosatellite currently orbiting the earth. We explain how this approach has overcome existing problems, has led to improved designs, and has provided new insights

A systematic archaeological survey in the environs of Khaytabad Tepa (Southern Uzbekistan). Preliminary report on the 2021 pilot season

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Steven MARCUS, Jiní viktoriáni: Studie o sexualitě a pornografii v Anglii v polovině 19. století, Praha, Nakladatelství Academia 2022, 235 s. ISBN 978-80-200-3392-5

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