Wyniki wyszukiwania - BazTech

1

Digital phase-location system for marine applications

Sadowski J., Stefański J.

Zeszyty Naukowe Akademii Marynarki Wojennej

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2017

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R. 58 nr 3 (210)

97--106

EN

This paper presents concept and implementation of digital phase-location system, de-signed as a navigational aid for marine applications. Main feature of proposed system is the ability to work in both synchronous mode, with one master station and set of slave stations synchronized with master, and in asynchronous mode with independent clocking of all stations.

PL

Artykuł zawiera opis działania oraz budowy prototypu cyfrowego systemu fazolokacyjnego. System ten został zaprojektowany do obsługi nawigacji morskiej, przy czym jego cechą charakterystyczną jest możliwość pracy zarówno w trybie synchronicznym, z wyróżnioną stacją główną oraz zestawem stacji podległych, jak i w trybie asynchronicznym, w którym wszystkie stacje bazowe są taktowane niezależnie z własnych generatorów wzorcowych.

2

Asynchroniczny system fazolokacyjny

Sadowski J., Stefański J.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2017

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nr 6

501--504, CD

PL

Referat zawiera opis prototypu systemu fazolokacyjnego w wersji asynchronicznej. Przedstawione zostały założenia wstępne, konstrukcja systemu oraz parametry użytkowe, uzyskane podczas testów systemu w warunkach laboratoryjnych.

EN

This paper presents prototype of asynchronous radiolocation system based on phase measurements. Initial assumptions, construction of system elements and parameters measured in laboratory are briefly described.

3

Towards partial order reductions for fragments of alternating-time temporal logic

Dembiński P., Jamroga W., Mazurkiewicz A., Penczek W.

Prace Instytutu Podstaw Informatyki Polskiej Akademii Nauk

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2016

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Nr 1036

1--32

EN

A general semantics of strategic abilities of agents in asynchronous systems with and without perfect information is proposed, and some general complexity results for verification of strategic abilities in asynchronous systems are presented. A methodology for partial order reduction (POR) in verification of agents with imperfect information is developed, based on the notion of traces introduced by Mazurkiewicz. Two semantics of ATL∗ −X are considered and it is shown that for memoryless imperfect information (|=ir) contrary to memoryless perfect information (|=Ir), one can apply techniques known for LTL−X.

PL

Raport definiuje ogólną semantykę dla strategicznych umiejętności agentów w systemach asynchronicznych z pełną i częściową informacją, oraz prezentuje ogólne wyniki dotyczące złożoności weryfikacji strategicznych możliwości w systemach asynchronicznych. Metoda redukcji częścio-porządkowych, wykorzystująca ślady Mazurkiewicza, została zastosowana do weryfikacji agentów z niepełną informacją. Dla rozważanych dwóch semantyk logiki ATL*_x zostało pokazane, że dla bezpamięciowej niepełnej informacji (|=ir) w przeciwieństwie do bezpamięciowej pełnej informacji (|=Ir), można zastosować metody znane dla LTL_x.

4

Correct-by-Construction Asynchronous Implementation of Modular Synchronous Specifications

Potop-Butucaru D., Caillaud B.

Fundamenta Informaticae

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2007

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Vol. 78, nr 1

131-159

EN

In this paper, we introduce a new model for the representation of distributed asynchronous implementations of synchronous specifications. The model covers classical implementations, where a notion of global synchronization is preserved by means of signaling, and globally asynchronous, locally synchronous (GALS) implementations where the global clock is removed. The new model offers a unified framework for reasoning about two essential correctness properties of an implementation: the preservation of semantics and the absence of deadlocks. We use it to derive criteria ensuring the correct deployment of synchronous specifications over GALS architectures. As the model captures the internal concurrency of the synchronous specification, our criteria support implementations that are less constrained and more efficient than existing ones. Our work also reveals strong ties between abstract semantics-preservation properties and more operational ones like the absence of deadlocks.

5

Embedding Universal Delay-Insensitive Circuits in Asynchronous Cellular Spaces

Lee J., Adachi S., Peper F., Morita K.

Fundamenta Informaticae

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2003

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Vol. 58, nr 3,4

295--320

EN

Asynchronous Cellular Automata (ACA) are cellular automata which allow cells to be updated at times that are random and independent of each other. Due to their unpredictable behavior, ACA are usually dealt with by simulating a timing mechanism that forces all cells into synchronicity. Though this allows the use of well-established synchronous methods to conduct computations, it comes at the price of an increased number of cell states. This paper presents a more effective approach based on a 5-state ACA with von Neumann neighborhood that uses rotation- and reflection-symmetric transition rules to describe the interactions between cells. We achieve efficient computation on this model by embedding so-called Delay-Insensitive circuits in it, a type of asynchronous circuits in which signals may be subject to arbitrary delays, without this being an obstacle to correct operation. Our constructions not only imply the computational universality of the proposed cellular automaton, but also allow the efficient use of its massive parallelism, in the sense that the circuits operate in parallel and there are no signals running around indefinitely in the circuits in the absence of input.

6

Communication complexity for multi-speed cooperating automata

Jurdziński T., Kutyłowski M., Rzechonek P., Zatopiański J.

Prace Naukowe Instytutu Matematyki Politechniki Wrocławskiej. Konferencje

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2001

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Vol. 24, nr 3

17-30

EN

We consider bounded memory asynchronous systems. They consist of finite automata working independently and communicating by exchanging messages. We discuss what impact the differences in timing models on computational power of such systems have. It is known that a total lack of synchronization has profound consequences for computational power of systems of automata. Lower bounds found for this model indicate that the only way to perform a nontrivial computation would be to re-synchronize the automata every 0(1) steps. We examine much weaker form of asynchronism. We consider the model in which automata work with constant speeds, but the speed might be different for each automaton, and the automata have no knowledge about the speeds. (We call this model multi-speed systems of finite automata.) In particular, it may happen that some speed cannot be expressed exactly by the means of internal states of automata. Nevertheless, we expect the automata to compute the correct output. The main result of this paper is that, quite unexpectedly, the systems described might be as powerful as synchronous systems, where all automata work with the same speed. More precisely, some languages, which have been candidates for distinguishing multi-speed and synchronous models, can be recognized by multi-speed systems with approximately the same number of messages sent.

7

Formal asynchronous systems modelling

Kohn M., Schmeck H.

Fundamenta Informaticae

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2000

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Vol. 42, nr 3,4

335-389

EN

In this paper a formal model for asynchronous systems behaviour is presented which is suited for representing all levels of abstraction appearing in the design process. Based on a structural abstraction of asynchronous computation systems called asynchronous nets the behaviour of an asynchronous system can be represented by a set of so called abstract computations. It is shown how basic properties of such systems, and in particular, delay-insensitive behaviour, could be determined by investigating properties of abstract computations. Finally, it is demonstrated that the model enables formal verification of asynchronous systems over different levels of abstraction.

8

Concurrent realizations of reactive systems

Bednarczyk M., Borzyszkowski A.

Prace Instytutu Podstaw Informatyki Polskiej Akademii Nauk

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1999

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nr 881

3-23

PL

Omawiany jest problem znajdowania (funktorialnej) współbieżnej realizacji systemu reaktywnego jako etykietowanej bezpiecznej sieci Petriego. Najpierw opisana jest funktorialna konstrukcja prowadząca z kategorii konkretnych systemów asynchronicznych, wprowadzonych przez Morina, do kategorii etykietowanych bezpiecznych sieci Petriego. Następnie omówiony jest problem w pełnej ogólności. Na ogół nie istnieje optymalne rozwiązanie, tzn. nie istnieje najbardziej współbieżna realizacja systemu reaktywnego. Niemniej wskazana jest droga budowania pewnej współbieżnej realizacji systemu reaktywnego.

EN

The problem of finding a (functional) concurrent realization of a reactive system by means of labelled safe Petri net is studied. Firstly, a (functional) construction is described that leads from the category of concrete asynchronous systems introduced by Morin to the category of labelled safe Petri nets. Then, the general problem is discussed. It is indicated that in general there are no optimal solutions, i.e., that the most concurrent realizations of a reactive system need not exist. Nevertheless, a framework to support the process of building a concurrent realization of a reactive system is presented.

9

General response time computation for the deadline driven scheduling of periodic tasks

Devillers R., Goossens J.

Fundamenta Informaticae

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1999

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Vol. 40, Nr 2,3

199-219

EN

In this paper we study the problem of scheduling hard real-time periodic task sets with a dynamic and preemptive scheduler. We will focus on the response time notion, its interest and its effective computation for the deadline driven scheduler. We present a general calculation procedure for determining the response time of the kth request of a task in asynchronous systems with general as well as arbitrary deadlines. Finally, we analyze the performance of the computation so defined, both in terms of time and memory requirements.