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1
Content available On Grünwlad-Letinkov fractional operator with measurable order on continuous-discrete time scale
Pawłuszewicz Ewa, Koszewnik Andrzej, Burzyński Piotr
Acta Mechanica et Automatica
|
2020
|
Vol. 14, no. 3
161--165
EN
Considering experimental implementation control laws on digital tools that measurement cards are discharged every time unit one can see that time of simulations is partially continuous and partially discrete. This observation provides the motivation for defining the Grünvald-Letnikov fractional operator with measurable order defined on continuous-discrete time scale. Some properties of this operator are discussed. The simulation analysis of the proposed approach to the Grünwald-Letnikov operator with the measurement functional order is presented.
2
Analiza pojemności bufora i skali czasu autokorelacji ruchu
Rusek K., Papir Z.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2015
|
nr 8-9
730--732
PL
Zaobserwowano i opisano istnienie zależności pomiędzy pojemnością bufora urządzenia sieciowego, skalą czasu, dla której model ruchu dokładnie opisuje jego funkcję autokorelacji i dokładnością wyznaczania współczynnika strat z takiego modelu.
EN
A relationship was observed between (i) the buffer capacity of the network device (ii) the time scale on which the traffic model accurately describes its autocorelation function (iii) the accuracy of packet loss ratio calculation from this model.
3
Content available Random integral equations on time scales
Lupulescu V., Lungan C.
Opuscula Mathematica
|
2013
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Vol. 33, no. 2
323--335
EN
In this paper, we present the existence and uniqueness of random solution of a random integral equation of Volterra type on time scales. We also study the asymptotic properties of the unique random solution.
4
Content available Positive realizations on time scales
Bartosiewicz Z.
Control and Cybernetics
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2013
|
Vol. 42, no. 2
315--327
EN
The problem of realization of a linear input-output map as a positive linear system on a time scale is studied. To state the criteria of existence of realization, modified Markov parameters corresponding to the input-output map are introduced. It is necessary for the existence of a positive realization that the modified Markov parameters be nonnegative. A necessary and sufficient condition for realizability is expressed in the language of positive cones in an infinite dimensional space. The sequence of modified Markov parameters generates one of the cones that appear in the criterion of realizability.
5
Content available On positive reachability of time-variant linear systems on time scales
Bartosiewicz Z.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2013
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Vol. 61, nr 4
905--910
EN
Positive reachability of time-variant linear positive systems on arbitrary time scales is studied. It is shown that the system is positively reachable if and only if a modified Gram matrix corresponding to the system is monomial. The general criterion is then specified for particular cases of continuous-time systems and various classes of discrete-time systems. It is shown that in the case of continuous-time systems with analytic coefficients the conditions for positive reachability are very restrictive, similarly as for time-invariant systems.
6
Content available Nowe wyzwania w hydrogeologii – europejski projekt FP7 GENESIS
Witczak S., Kania J., Malina G., Postawa A., Żurek A., Duliński M., Różański K., Wachniew P., Nikiel G.
Biuletyn Państwowego Instytutu Geologicznego
|
2013
|
nr 456 Hydrogeologia z. 14/2
633--643
PL
W artykule krótko przedstawiono charakterystykę europejskiego projektu FP-7 GENESIS oraz doświadczenia wynikające z badania polskich obszarów testowych włączonych do projektu. W zrozumieniu systemu krążenia wód podziemnych najważniejsza jest rola skali czasowej oraz ocena środowiskowej roli wody. W prezentacji skali czasowej bardzo ważne są proste modele konceptualne. Bardziej zaawansowane modelowanie numeryczne wymaga nowych metod ograniczających niepewność prognoz. Jedną z przedstawionych w artykule metod jest kalibracja modeli przepływu i transportu przy pomocy znaczników środowiskowych w kolejnych krokach zależnych od dostępnych danych oraz przedziałów wieków wody.
EN
The paper briefly describes the European FP7 project GENESIS and lessons learned from the Polish case studies involved into the project. The most important are the role of time scales in understanding the groundwater flow system and environmental water requirements. Simple conceptual models are very important for time scale presentation. More sophisticated numerical modeling needs new methods of uncertainty control. One of them shown in the paper is calibration of flow and transport models with the aid of tracers in steps related to available data and age ranges.
7
Content available Null-Controllability of Linear Systems on Time Scales
Pawłuszewicz E.
Acta Mechanica et Automatica
|
2012
|
Vol. 6, no. 4
50-55
EN
The purpose of the paper is to study the problem of controllability of linear control systems with control constrains, defined on a time scale. The obtained results extend the existing ones on any time domain. The set of values of admissible controls is a given closed and convex cone with nonempty interior and vertex at zero or is a subset of containing zero.
8
Content available Jurassic Chronostratigraphic Database and the TimeScale Creator Visualization System
Ogg J., Przybylski P.
Volumina Jurassica
|
2009
|
Vol. 7, no. 1
175-179
EN
A joint project of the International Commission on Stratigraphy (ICS) and CHRONOS database program is to provide detailed global and regional “reference” scales of Earth history. Such scales integrate biostratigraphy (zones, datums for marine and terrestrial realms), sea-level (curves, sequences), geochemistry (trends, events), magnetic polarity chrons and astronomical cycles. The current Jurassic scale contains over 1000 events and zones correlated to Tethyan and Boreal ammonite zones with approximate numerical ages from Geologic Time Scale 2004 (Gradstein et al. 2004). This public database will be progressively enhanced through the efforts of the Jurassic Subcommission of the ICS and by other stratigraphic and regional experts. On-screen display and production of usertailored time-scale charts is provided by the TimeScale Creator, a Java package freely available from the ICS Subcommission for Stratigraphic Information or the TS-Creator websites (http://stratigraphy.science.purdue.edu or www.tscreator.org). After specifying the time interval and vertical scale, a user selects a subset of stratigraphic columns and trends. In addition to screen views and a scalable-vector graphics (SVG) file for importation into popular graphics programs, the on-screen display also has “hot-curser-points” to open windows providing additional information on events, zones and boundaries. The database and visualization package are envisioned as a convenient reference tool, chart-production assistant, and a window into the geologic history of our planet.
9
Czas i jego skale w nawigacyjnych systemach satelitarnych
Januszewski J.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2009
|
nr 12
2015-2021
PL
Pod koniec pierwszej dekady trzeciego tysiąclecia zagadnienia związane z czasem, jego znajomością i wykorzystaniem są obiektem bardzo dużego zainteresowania zarówno ze strony wąskiego grona naukowców, jak i milionów ludzi całego świata. Określanie pozycji za pomocą nawigacyjnych systemów satelitarnych opiera się na pomiarze czasu propagacji sygnału na trasie satelita odbiornik użytkownika, a sygnał ów jest jednocześnie źródłem czasu dla wielu odbiorców. W artykule po omówieniu definicji sekundy, stref czasowych wybranych państw oraz stosowanych obecnie skal czasu, takich jak czas uniwersalny (UT) i czas skoordynowany UTC, opisano skale czasu systemów GPS, GLONASS i Galileo, ich wzajemne relacje oraz informacje o czasie przesyłane w depeszach nawigacyjnych satelitów w/w systemów.
EN
In the later part the first decade of the third millennium connected problems over time, his knowledge and an utilization are an object of the very large interest both on the part of the narrow circle of specialists, as and millions of users of the all the world. The position fix by means satellite navigation systems is based on the measurement of the propagation time of the signal from satellite to the user's receiver, and this signal is simultaneously a source of the time for many receivers. In this paper after the definition of the second, zones of temporary chosen states and actual time scales as the universal time UT and universal time coordinated UTC, the time scales of the GPS, GLONASS and Galileo systems, the translation of satellite time to UTC/TAI and the data concerning the time in navigation messages transmitted by the satellites are described.
10
Content available remote Modelling of Complex Systems: Systems as Dataflow Machines
Bliudze S., Krob D.
Fundamenta Informaticae
|
2009
|
Vol. 91, nr 2
251-274
EN
We develop a unified functional formalism for modelling complex systems, that is to say systems that are composed of a number of heterogeneous components, including typically software and physical devices. Our approach relies on non-standard analysis that allows us to model continuous time in a discrete way. Systems are defined as generalized Turing machines with temporized input, internal and output mechanisms. Behaviors of systems are represented by transfer functions. A transfer function is said to be implementable if it is associated with a system. This notion leads us to define a new class - which is natural in our framework - of computable functions on (usual) real numbers. We show that our definitions are robust: on one hand, the class of implementable transfer functions is closed under composition; on the other hand, the class of computable functions in our meaning includes analytical functions whose coefficients are computable in the usual way, and is closed under addition, multiplication, differentiation and integration. Our class of computable functions also includes solutions of dynamical and Hamiltonian systems defined by computable functions. Hence, our notion of system appears to take suitably into account physical systems.
11
Content available remote Czasowe i przestrzenne skale turbulencji w mieszalniku wielostopniowym
Talaga J.
Czasopismo Techniczne. Mechanika
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2008
|
R. 105, z. 2-M
351-360
PL
W pracy przedstawiono wyniki badań doświadczalnych, których celem było określenie czasowych i przestrzennych mikroskal i makroskal turbulencji cieczy w mieszalniku wielostopniowym z dwoma mieszadłami usytuowanymi na wspólnym wale. Wielkości te wyznaczano w oparciu o funkcję autokorelacji prędkości fluktuacyjnych, uzyskaną na podstawie wyników pomiarów chwilowych prędkości przepływu cieczy w mieszalniku. Wyznaczone wielkości skal turbulencji porównano dla sześciu różnych kombinacji dwóch mieszadeł na wale oraz dla różnych odległości między mieszadłami.
EN
In the paper the results of investigations of time and length turbulence macro and micro scales for mixing vessel with multiple impellers are presented. These quantities were determined on the ground of the autocorrelation function of rms velocities, calculated on the basis of instantaneous velocities of flow in the mixing vessel. The values of turbulence scales obtained were compared for six different configurations of dual-impeller systems and different distances between impellers.
12
Content available remote Czas na ziemi i w kosmosie - wybrane aspekty metrologii czasu i częstotliwości
Czubla A., Fotowicz P.
Pomiary Automatyka Robotyka
|
2007
|
R. 11, nr 2
PL
Niniejszy artykuł przybliża tematykę współczesnej metrologii czasu i częstotliwości. Przedstawione są tu dwa najważniejsze zagadnienia dzisiejszej metrologii czasu i częstotliwości: wyznaczanie międzynarodowych atomowych skal czasu oraz utrzymywanie i funkcjonowanie globalnych systemów nawigacji satelitarnej. Dodatkowo opisane zostały wybrane aspekty związane bezpośrednio z praktyką pomiarów w tej dziedzinie.
EN
This paper is aimed at making contemporary time and frequency metrology more familiar to the readers. Two most important issues of today’s time and frequency metrology are presented here: determination of international atomic timescales as well as maintenance and operation of global navigation satellite systems. Additionally, same aspects directly connected to the practice of measurements in this field have been described herein.
13
Content available remote The age of the Triassic/Jurassic boundary: new data and their implications for the extinction and recovery
Pálfy J., Mundil R.
Volumina Jurassica
|
2006
|
Vol. 4, no. 1
294-294
EN
Providing accurate and precise radio-isotopic ages for the Triassic/Jurassic (T/J) boundary is a goal for time scale calibration but it also bears on the timing and causality of the end-Triassic mass extinction and subsequent recovery. The currently used estimate of the T/J boundary age hinges on a multi-grain zircon U-Pb age from a marine T/J boundary section in the Queen Charlotte Islands, Canada (199.6±0.4 Ma, Pálfy et al. 2000), and ⁴⁰Ar/³⁹Ar ages of volcanism of the Central Atlantic Magmatic Province (CAMP) cluster around 199.9 Ma (Knight et al. 2004), supporting a hypothesis that implicates this Large Igneous Province in triggering severe environmental changes and the biotic extinction. However, the apparent synchrony of the end-Triassic extinction and CAMP volcanism requires scrutiny for at least two reasons. Multi-grain zircon U-Pb analyses are prone to leave slight Pb loss undetected, hence producing marginally younger ages. Comparison of ⁴⁰Ar/³⁹Ar and U-Pb dates is affected by a current revision of the decay constant of ⁴⁰K and the age of fluence monitors that may require recalculation of all Phanerozoic ⁴⁰Ar/³⁹Ar ages and their upward adjustment by ˜1% (e.g. Min et al. 2000). Here we present new single-crystal zircon U-Pb ages that provide new constraints on the T/J boundary. Applying the pretreatment of thermal annealing and chemical abrasion (Mattinson 2005) resulted in a coherent cluster of zircon ages with a preliminary ²⁰⁶Pb/²³⁸U age of 198.0±0.6 Ma from a volcanic tuff layer within Early Sinemurian sediments in the Mecsek Mts., southern Hungary. The same method yielded an age of 200.6±0.3 Ma for a volcanic ash layer in ammonite-bearing Middle Hettangian marine sediments at Puale Bay, Alaska. The Early Sinemurian age provides an upper limit for the earliest Jurassic recovery interval. The two new ages suggest that the T/J boundary might be older than previously thought, likely >201 Ma. Considering the systematic bias in existing ⁴⁰Ar/³⁹Ar ages for the CAMP, synchrony of volcanism and extinction remains a strong possibility but requires further tests. Significantly, a single-crystal 206Pb/238U age of 201.3±0.3 Ma has been reported from the North Mountain basalt, a CAMP flow in Nova Scotia, Canada (Schoene et al. 2006). Further dating effort is needed to re-analyze critically important volcanic ash layers from the T/J boundary sections of the Queen Charlotte Islands.
14
Content available remote Jurassic cyclostratigraphy: recent advances, implications and problems
Coe A., Weedon G.
Volumina Jurassica
|
2006
|
Vol. 4, no. 1
156-157
EN
About 70% of the Jurassic is now covered by floating astronomical timescales based on the recognition of Milankovitch cycles. Astronomical timescales provide the highest resolution robust timescales over the tens of thousands to millions and even tens of millions of year timescales. This presentation will provide a summary of the status of the Jurassic astronomical timescale, including the outstanding problems and possible solutions. The oldest sea-floor magnetic anomaly pattern is Callovian. For earlier stages the scaling for the Geological Timescale 2004 (Gradstein et al. 2004), other than minimum estimates from direct counts of stratigraphic cycles, relied on a combination of c. 20 radiometric dates, the number of ammonite subzones and an assumption that the rate of change of seawater 87Sr/86Sr ratio for the Early Jurassic was linear over intervals of millions of years. However, this assumption has recently been questioned and thus there is an additional need to improve the cyclostratigraphic and radiometric databases. Cyclostratigraphy for much of the Early Jurassic has been completed using sections in England and the Alps. There is no cyclostratigraphy for the Bajocian and Bathonian. For the Late Jurassic, the existence of a sea-floor magnetic anomaly pattern together with recent and ongoing cyclostratigraphic and magnetostratigraphic studies on the same sections in the UK provide the potential to produce a high-resolution integrated timescale for the Callovian to Tithonian (c. 15 Ma duration). However, construction of the Late Jurassic timescale is complex because of the high number of magnetic reversals, the provincialism of the ammonites used for biostratigraphy and lack of agreement on the stages. Weedon et al. (2004) identified regular cycles in the Kimmeridge Clay Formation in England and used these to construct a floating 7.5 Ma astronomical timescale for the latest Oxfordian (as defined in the Tethyan province), Kimmeridgian and most of the Early Tithonian. Comparison of this astronomical timescale with the GTS2004 reveals that the Early Tithonian is c. 1 Ma (25%) longer according to the cyclostratigraphy. This mismatch may be resolved via better correlation of the magnetozones that were defined in France (Tethyan Province) and the Kimmeridge Clay Formation (Boreal Province). For the Oxfordian and Callovian a high-resolution magnetostratigraphy based on sections in the UK has recently been compiled. Work is currently being conducted to produce a floating astronomical timescale using exactly the same exposures.
15
Content available remote Jurassic Chronostratigraphic Charts and a Display Interface. 1. Hettangian through Aalenian. 2. Bajocian through Tithonian
Przybylski P., Ogg J.
Volumina Jurassica
|
2006
|
Vol. 4, no. 1
199-199
EN
A joint project of the International Commission on Stratigraphy (ICS) and CHRONOS database program is to provide detailed global and regional “reference” scales of Earth history. Such scales integrate biostratigraphy (zones, datums for marine and terrestrial realms), sea-level (curves, sequences), geochemistry (trends, events), magnetic polarity chrons and astronomical cycles. These summarize our current consensus on the inter-calibration of events, their relationships to international divisions of geologic time and their estimated numerical ages. An initial Phanerozoic database (about 9000 events and zones in April 2006) includes definitions of geologic stages, major zonations and markers of all significant fossil groups, primary and secondary magnetic polarity scales, and other stratigraphic information. Annotations on each entry include source, reliability, selected taxonomic notes, inter-calibrations, and methods of interpolating numerical age. This database will be enhanced through the efforts of the subcommissions of the ICS and other stratigraphic and regional experts. A primary source for the Jurassic was the extensive “Mesozoic and Cenozoic Sequence Chronostratigraphic Framework of European Basins” chart series of inter-calibrated bio-, magneto-, chemoand sequence stratigraphy (Hardenbol et al. 1998) which had been calibrated to the geologic time scales of 1995. We recalibrated all these chronostratigraphic and sequence stratigraphy events to Geologic Time Scale 2004 (Gradstein et al. 2004) and included selected post-1995 biostratigraphic schemes, marker events and geochemistry correlated to Tethyan and Boreal ammonite zones. On-screen display and production of user-tailored time-scale charts is provided by the Time-Scale Creator, a JAVA package available from the ICS/CHRONOS websites (www.stratigraphy.org or www.chronos.org). After specifying the time interval and vertical scale, a user selects a subset of stratigraphic columns and trends. In addition to screen views and a scalable-vector graphics (SVG) file for importation into popular graphics programs (e.g., Adobe Illustrator), the on-screen display has “hot-curser-points” to open windows providing additional information on events, zones and boundaries. The database and visualization package are envisioned as a convenient reference tool, chart-production assistant, and a window into the geologic history of our planet. We present sample output for the Jurassic portion as a pair of large-format charts: Hettangian-Aalenian by Ogg and Przybylski, and an accompanying poster for Bajocian-Tithonian by Przybylski and Ogg.
16
Content available The asymptotic properties of the dynamic equation with a delayed argument
Cermak J., Urbanek M.
Opuscula Mathematica
|
2006
|
Vol. 26, no. 3
421-429
EN
In this paper, we present some asymptotic results related to the scalar dynamic equation with a delayed argument. Using the time scale calculus we generalize some results known in the differential and difference case to the more general dynamie case.
17
Content available remote Realization of atomic SI second definiotion in the context UTC(PL) and TA(PL)
Czubla A., Konopka J., Nawrocki J.
Metrology and Measurement Systems
|
2006
|
Vol. 13, nr 2
149-159
EN
In this paper, the problem of practical realization of atomic SI second definition is discussed from the metrological point of view. Special attention is devoted to the maintenance of UTC(PL) - Polish local physical realization of UTC, and to the determination of TA(PL) - the Polish independent atomic timescale. The role of such timescales, as well as local and international cooperation in time and frequency metrology is also considered. We share some Polish experience in this field.
PL
Przy realizacji atomowej definicji sekundy na najwyższym poziomie dokładności samo posiadanie atomowych wzorców czasu i częstotliwości nie wystarcza. Wymagane jest również prowadzenie szerokiej lokalnej i międzynarodowej współpracy laboratoriów czasu i częstotliwości. W celu zachowania wysokiej dokładności zegary atomowe powinny być w sposób ciągły ze sobą porównywane i niezbędny jest ich udział w tworzeniu międzynarodowych i lokalnych atomowych skal czasu. Z tego względu atomowe skale czasu UTC(PL) i TA(PL) pełnią istotną rolę w zachowaniu wysokiej dokładności pomiarów czasu i częstotliwości w Polsce. UTC(PL) stanowi główną skalę odniesienia dla porównań zegarów atomowych i skal czasu w Polsce i umożliwia im dowiązanie do UTC. Dlatego bardzo ważne jest utrzymywanie UTC(PL) jak najbliżej UTC, co jest procesem złożonym i wymaga prognozowania skali czasu UTC(PL) względem UTC. Z kolei wyznaczanie TA(PL), możliwe dzięki utworzeniu w Polsce rozproszonej sieci porównań zegarów atomowych przy użyciu metody GPS CV, stymuluje rozwój wyznaczania i prognozowania skal czasu, zobowiązuje laboratoria biorące udział w TA(PL) do prowadzenia regularnej współpracy na odpowiednio wysokim poziomie merytorycznym oraz gwarantuje regularną ocenę stabilności wzorców atomowych. Wszystkie te działania prowadzą do podnoszenia dokładności odtwarzania jednostek miar czasu i częstotliwości i są one w Polsce ciągle rozwijane i doskonalone.
18
Content available remote Realizations of linear control systems on time scales
Bartosiewicz Z., Pawłuszewicz E.
Control and Cybernetics
|
2006
|
Vol. 35, no 4
769-786
EN
Linear constant-coefficients control systems with output on arbitrary time scales are studied. Kalman criteria of controllability and observability are extended to such systems. The main problem is to find criteria for an abstract input/output map to have a realization as a system on the time scale. Two different characterizations of realizability are proved. They extend the classical results obtained for continuous-time and discrete-time systems. Minimal realizations and their uniqueness are also studied.
19
Content available remote Rozwój miejscowego rozmycia w czasie na modelach jazu w dwóch skalach
Urbański J.
Przegląd Naukowy Inżynieria i Kształtowanie Środowiska
|
2005
|
Vol. 14, No. 1
67--75
EN
Paper presented analysis results of investigations of influence scale model on formation of scour in time. Investigations were conducted on two model this same taired constructions with the over of water under the closure, bottom of water basins and washing-out area. Models were made in two skales 1 : 30 and 1 : 55. In inwestigations were used this same eroded materiał on two models - sand. Estimated change of parameter for morfological time scale between two models of the dam. In Froudian models with a nonlinearly scaled size of sand grains the maximum depth of local scour develop slower than their linear counterparts in prototypes, except for the initial stage of scour.
20
Content available remote An eigenvalue problem for linear Hamiltonian dynamic systems
Bohner M., Hilscher R.
Fasciculi Mathematici
|
2005
|
Nr 35
35-49
EN
In this paper we consider eigenvalue problems on time scales involving linear Hainiltonian dynamic systems. We give conditions that ensure that the eigenvalues of the problem are isolated and bounded below. The presented results are applicable also to Sturm-Liouville dynamic equations of higher order, and further special cases of our systems are linear Hamiltonian differ ential systems as well as linear Hamiltonian difference systems.
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