Modelování a simulace komplexních systémů

1 Úvod S: Podívej, pořídil jsem si novou knihu. M: nechápu, proč si v dnešní době ještě kupuješ knihy. Všechno najdeš na internetu. S: To je ta dnešní mládež, všechno by hledala na internetu. Jenže abys něco našel na internetu, nejdřív potřebuješ vědět, co vlastně máš hledat. navíc intelektuální stravování na internetu se podobá stravování ve fast-foodu: rychle, levně, nekvalitně a většinou si k tomu dáš nezdravý zákusek, který jsi původně vůbec nechtěl. M: Přestaň mě poučovat a raději mi řekni, o čem je ta tvoje nová kniha? S: Jmenuje se "Modelování a simulace komplexních systémů'. Modely určitě znáš: třeba mapa jako model terénu nebo autíčko na hraní jako model reálného auta. Tady v té knize se mluví o výpočetních modelech. Představ si třeba počítačový model pohybu koulí na kulečníkovém stolu - model tvoří rovnice popisující pohyb koulí, simulací tohoto modelu dostáváš obrázek na monitoru, který vizualizuje pohyb koulí

An Analysis of Response Times in Adaptive Practice of Geography Facts

ABSTRACT Online educational systems can easily measure both answers and response times. Student modeling, however, typically focuses only on correctness of answers. In this work we analyze response times from a widely used system for adaptive practice of geography facts. Our results show that response times have simple relationship with the probability of answering correctly the next question about the same item. We also analyze the overall speed of students and its relation to several aspects of students' behaviour within the system

An Efficient Normalisation Procedure for Linear Temporal Logic and Very Weak Alternating Automata

In the mid 80s, Lichtenstein, Pnueli, and Zuck proved a classical theorem stating that every formula of Past LTL (the extension of LTL with past operators) is equivalent to a formula of the form $\bigwedge_{i=1}^n \mathbf{G}\mathbf{F} \varphi_i \vee \mathbf{F}\mathbf{G} \psi_i$, where $\varphi_i$ and $\psi_i$ contain only past operators. Some years later, Chang, Manna, and Pnueli built on this result to derive a similar normal form for LTL. Both normalisation procedures have a non-elementary worst-case blow-up, and follow an involved path from formulas to counter-free automata to star-free regular expressions and back to formulas. We improve on both points. We present a direct and purely syntactic normalisation procedure for LTL yielding a normal form, comparable to the one by Chang, Manna, and Pnueli, that has only a single exponential blow-up. As an application, we derive a simple algorithm to translate LTL into deterministic Rabin automata. The algorithm normalises the formula, translates it into a special very weak alternating automaton, and applies a simple determinisation procedure, valid only for these special automata.Comment: This is the extended version of the referenced conference paper and contains an appendix with additional materia

Distributed MAP in the SpinJa Model Checker

Spin in Java (SpinJa) is an explicit state model checker for the Promela modelling language also used by the SPIN model checker. Designed to be extensible and reusable, the implementation of SpinJa follows a layered approach in which each new layer extends the functionality of the previous one. While SpinJa has preliminary support for shared-memory model checking, it did not yet support distributed-memory model checking. This tool paper presents a distributed implementation of a maximal accepting predecessors (MAP) search algorithm on top of SpinJa.Comment: In Proceedings PDMC 2011, arXiv:1111.006

Czech Republic On-the-fly State Space Reductions £

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