In this paper we present novel results for discrete-time and Markovian continuous-time multitype branching processes. As a population develops, we are interested in the waiting time until a particular type of interest...
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In this paper we present novel results for discrete-time and Markovian continuous-time multitype branching processes. As a population develops, we are interested in the waiting time until a particular type of interest (such as an escape mutant) appears, and in how the distribution of individuals depends on whether this type has yet appeared. Specifically, both forward and backward equations for the distribution of type-specific population sizes overtime, conditioned on the nonappearance of one or more particular types, are derived. In tandem, equations for the probability that one or more particular types have not yet appeared are also derived. Brief examples illustrate numerical methods and potential applications of these results in evolutionary biology and epidemiology.
In this paper we study exact distributions of sooner and later waiting times for runs in Markov dependent bivariate trials. We give systems of linear equations with respect to conditional probabilitygenerating functi...
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In this paper we study exact distributions of sooner and later waiting times for runs in Markov dependent bivariate trials. We give systems of linear equations with respect to conditional probability generating functions of the waiting times. By considering bivariate trials, we can treat very general and practical waiting time problems for runs of two events which are not necessarily mutually exclusive. Numerical examples are also given in order to illustrate the feasibility of our results.
Wireless body area networks (WBANs) play an important role in human health monitoring for mobile healthcare. The improvement of service performance and low-power consumption are the two challenges for these medical WB...
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Wireless body area networks (WBANs) play an important role in human health monitoring for mobile healthcare. The improvement of service performance and low-power consumption are the two challenges for these medical WBANs, because those energy-limited wireless medical sensors must transmit the monitoring data to the personal server (PS) via intra-WBAN in time. Further, precise mathematical modeling combining with the sleeping state to measure this improvement theoretically is still lack. Therefore, a polling control with exhaustive service using the sleeping schema is proposed to address the problems in WBANs communication for smart health. Based on the managed access phase (MAP) specified in the IEEE 802.15.6 standard, it has been attempting to improve the energy efficiency through a self-managing sleeping schema for both the sensor nodes and the PS according to the load in intra-WBANs, in which the node will soon turn to sleep upon completion of transmitting all its current data packets. Additionally, by employing the embedded Markov chain and probability generating function, the proposed model is established, and the performance characteristics-the mean cyclic period and queue length at the polling moment-were accurately obtained to justify the service performance can be guaranteed. In addition, the expressions of the quantitative relationship among sleeping time, performance characteristics and network parameters were derived in closed form, which can easily evaluate the energy efficiency. Simulations were carried out to justify this model.
The two-parameter strict arcsine distribution as a member of the natural exponential family with cubic variance function has been shown to be a viable candidate for statistical analysis of count data. Efficient method...
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The two-parameter strict arcsine distribution as a member of the natural exponential family with cubic variance function has been shown to be a viable candidate for statistical analysis of count data. Efficient methods of parameter estimation will be essential in practical applications of the distribution. In this paper we examine some methods of parameter estimation. Due to the simple expression of the probability generating function, a probability generating function-based estimation procedure is considered and compared with other estimation procedures. Since the accuracy of the parameter estimation procedure affects the probability of correct selection in choosing the correct probability distribution, we extend the investigation by examining the discrimination between strict arcsine and generalized Poisson distributions in which both have cubic variance functions.
Uncertainties in common cause event observation, documentation and interpretation are taken into account by conditional probabilities and generalized impact vector weights that separate single and double events of a s...
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Uncertainties in common cause event observation, documentation and interpretation are taken into account by conditional probabilities and generalized impact vector weights that separate single and double events of a specific multiplicity in a single observation. Distributions and moments of common cause failure (CCF) rates of a system are obtained in terms of the weights by using probability generating functions, combining assessment uncertainties and statistical uncertainties. These results are then used to generate effective plant-specific input data to general empirical Bayes estimation methods to combine data from many plants. The posterior output yields CCF probabilities for standby safety system fault tree analysis or probabilistic safety assessments of a target plant. (C) 2002 Published by Elsevier Science Ltd.
We consider a two-dimensional time-inhomogeneous birth-death process to model the time-evolution of fake news in a population. The two components of the process represent, respectively: (i) the number of individuals (...
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We consider a two-dimensional time-inhomogeneous birth-death process to model the time-evolution of fake news in a population. The two components of the process represent, respectively: (i) the number of individuals (say spreaders) who know the rumor and intend to spread it and (ii) the number of individuals (say inactives) who have forgotten the rumor previously received. We employ the probability generating function-based approach to obtain the moments and the covariance of the two-dimensional process. We also analyze a new adimensional index to study the correlation between the two components. Some special cases are considered in which both the expected numbers of spreaders and inactives are equal to suitable sigmoidal curves, which are often adopted in modeling growth phenomena. Finally, we provide an application based on real data related to the diffusion of fake news, in which the optimal choice of the sigmoidal curve that fit the datasets is based on the minimization of the mean square error and of the relative absolute error.
In this paper we study exact distributions of runs on directed trees. On the assumption that the collection of random variables indexed by the vertices of a directed tree has a directed Markov distribution, the exact ...
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In this paper we study exact distributions of runs on directed trees. On the assumption that the collection of random variables indexed by the vertices of a directed tree has a directed Markov distribution, the exact distribution theory of runs is extended from based on random sequences to based on directed trees. The distribution of the number of success runs of a specified length on a directed tree along the direction is derived. A consecutive-k-out-of-n:F system on a directed tree is introduced and investigated. By assuming that the lifetimes of the components are independent and identically distributed, we give the exact distribution of the lifetime of the consecutive system. The results are not only theoretical but also suitable for computation.
In this paper,we consider the impatient customers in M/M/1 queueing model under variant working vacation *** customer’s impatience is due to its arrival during a working vacation period,where the service rate of the ...
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In this paper,we consider the impatient customers in M/M/1 queueing model under variant working vacation *** customer’s impatience is due to its arrival during a working vacation period,where the service rate of the customer is lower than a normal busy *** the system is non-empty when the server returns from the working vacation,the server resumes the normal service ***,the server will take successive working vacations till it reaches the maximum number of K working vacations and then the server remains idle until the next ***-form probabilities are obtained by using the identities involving beta functions and degenerate hypergeometric functions,and the performance measures of the system are derived using generating *** stochastic decomposition structures of the mean queue length and mean waiting time are *** effects of the system parameters on some performance measures had been numerically illustrated.
Let Z(1), Z(2),... be a sequence of independent Bernoulli trials with constant success and failure probabilities p = Pr(Zt = 1) and q = Pr(Zt = 0) = 1 -p, respectively, t = 1, 2,.... For any given integer k = 2 we con...
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Let Z(1), Z(2),... be a sequence of independent Bernoulli trials with constant success and failure probabilities p = Pr(Zt = 1) and q = Pr(Zt = 0) = 1 -p, respectively, t = 1, 2,.... For any given integer k = 2 we consider the patterns E1: two successes are separated by at most k -2 failures, E2: two successes are separated by exactly k -2 failures, and E3: two successes are separated by at least k -2 failures. Denote by N-n, k((i)) (respectively M-n, k,((i)) ) the number of occurrences of the pattern Ei, i = 1, 2, 3, in Z(1), Z(2),..., Zn when the non-overlapping (respectively overlapping) counting scheme for runs and patterns is employed. Also, let T ((i)) r, k (resp. W ((i)) r, k) be the waiting time for the r -th occurrence of the pattern Ei, i = 1, 2, 3, in Z(1), Z(2),... according to the non-overlapping (resp. overlapping) counting scheme. In this article we conduct a systematic study of N-n, k((i)), M-n, k,((i)) ,T-r,T-k ((i)) and W-r,W-k ((i)) (i = 1, 2, 3) obtaining exact formulae, explicit or recursive, for their probability generating functions, probability mass functions and moments. An application is given.
In this article the probability generating functions of the extended Farlie-Gumbel-Morgenstern family for discrete distributions are derived. Using the probability generating function approach various properties are e...
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In this article the probability generating functions of the extended Farlie-Gumbel-Morgenstern family for discrete distributions are derived. Using the probability generating function approach various properties are examined, the expressions for probabilities, moments, and the form of the conditional distributions are obtained. Bivariate version of the geometric and Poisson distributions are used as illustrative examples. Their covariance structure and estimation of parameters for a data set are briefly discussed. A new copula is also introduced. (C) 2009 Elsevier B.V. All rights reserved.
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