Wyniki wyszukiwania - BazTech

1

Porównywanie modeli kontaktów metodą porządkowania stochastycznego

Kamińska-Zabierowska M., Kamiński M.

Architectus

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2016

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Nr 3 (47)

73--84

PL

Nie jest znana uniwersalna metoda porównywania modeli kontaktów. Modele spotykane w literaturze są najczęściej zadane wzorem matematycznym, który opisuje swoistą charakterystykę modelu, ale niewiele mówi o jego działaniu. W niniejszej pracy zaproponowano sposób porównywania modeli kontaktów. Dzięki analitycznemu uruchomieniu modeli na idealnych, teoretycznych rozkładach porównano, jakie typy podróży preferuje model, jak rozkłada ruch oraz jak przedstawiają się te cechy w zestawieniu z innymi modelami. Kryterium porównawczym uczyniliśmy stochastyczne porządkowanie frakcji zrealizowanych kontaktów. Pomysł ten wydaje się dobrą alternatywą dla porównywania modeli na konkretnych miastach. Porównania dokonano dla modeli production constrained oraz intervening opportunity (modelu pośrednich możliwości). Wyniki otrzymane dla przyjętych rozkładów celów ukazują, że choć obydwa modele bardzo się różnią w swoich założeniach, w szczególnych przypadkach mogą podobnie realizować kontakty.

EN

No universal method for comparing contact models is known. Models we met in literature are usually stated by a complicated mathematical formula, which does not provide any information about the model’s specific behaviour, although it characterizes the model. In this paper the authors present their own way of comparing contact models. We run models in analytic theory on ideal theoretical distributions. Thanks to this we are able to compare multiple models and their behaviour in terms of arriving distribution or short/long trips preferences. We use stochastic ordering approach for fractions of completed contacts as the criterion for comparing models. The presented idea seems to be a good alternative to a comparison based on the model’s output for fixed city instances. Comparison is made for production constrained and intervening opportunity models. The results for chosen distributions show that, even if both models differ much in their assumptions, they can give very similar outputs.

2

A note on preservation of the generalized TTT transform order

Kamińska-Zabierowska M.

Probability and Mathematical Statistics

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2014

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Vol. 34, Fasc. 2

273--278

EN

The generalized total time on test (GTTT) transform with respect to the nonnegative function was introduced by Li and Shaked (2007). Comparing GTTT transforms of two distributions is useful in reliability theory and actuarial science, see, e.g., Li and Shaked (2007), Shaked et al. (2010). In 2009, Bartoszewicz and Benduch formulated the preserving theorem for some orders under the GTTT transform. We complete it with result for the GTTT transform order with respect to the nonnegative function. We give also some conditions for preservation under mixtures of exponential distributions and extend the theorem proved by Bartoszewicz and Skolimowska (2006).

3

On new aging classes based on the reversed mean residual life order

Ahmadi K., Rezaei M.

Control and Cybernetics

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2013

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Vol. 42, no. 3

727--737

EN

In this paper, we introduce new concepts of aging for lifetime distributions. The main idea is the comparison between reversed mean residual life of the random variables X and (X − t | X > t), for all t > 0. Firstly, with some examples, we highlight the role of the proposed aging classes in reliability and life testing. Then, we try to find the connection between the new aging classes and other aging classes well-known from the literature. Reliability properties of the new classes are studied. Formally, we derive the preservation property under monotonic transformations. Some Rother characterization and implications are studied.

4

Characterizations of the exponential distribution by geometric compound

Iwińska M., Popowska B.

Fasciculi Mathematici

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2011

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Nr 47

5--10

EN

Under the reliability conditions IFRA/DFRA (NBU/ NWU), the exponential distribution is characterized by stochas- tic ordering properties which link the geometric compound with record values (spacing of record values). The index of record val- ues is random.