Analysis of an SPP/G/1 system with multiple vacations and E-limited service discipline

Many researchers have studied variants of queueing systems with vacations. Most of them have dealt with M/G/1 systems and have explicitly analyzed some of their performance measures, such as queue length, waiting time, and so on. Recently, studies on queueing systems whose arrival processes are not Poissonian have appeared. We consider a single server queueing system with multiple vacations and E-limited service discipline, where messages arrive to the system according to a switched Poisson process. First, we consider the joint probability density functions of the queue length and the elapsed service time or the elapsed vacation time. We derive the equations for these pdf's, which include a finite number of unknown values. Using Rouché's theorem, we determine the values from boundary conditions. Finally, we derive the transform of the stationary queue length distribution explicitly.     

Analysis of NMAR missing data without specifying missing-data mechanisms in a linear latent variate model

It is natural to assume that a missing-data mechanism depends on latent variables in the analysis of incomplete data in latent variate modeling because latent variables are error-free and represent key notions investigated by applied researchers. Unfortunately, the missing-data mechanism is then not missing at random (NMAR). In this article, a new estimation method is proposed, which leads to consistent and asymptotically normal estimators for all parameters in a linear latent variate model, where the missing mechanism depends on the latent variables and no concrete functional form for the missing-data mechanism is used in estimation. The method to be proposed is a type of multi-sample analysis with or without mean structures, and hence, it is easy to implement. Complete-case analysis is shown to produce consistent estimators for some important parameters in the model.     

A family of non class-regular symmetric transversal designs of spread type

Many classes of symmetric transversal designs have been constructed from generalized Hadamard matrices and they are necessarily class regular. In (Hiramine, Des Codes Cryptogr 56:21–33, 2010) we constructed symmetric transversal designs using spreads of \mathbbZ_p²ⁿ{\mathbb{Z}_p^{2n}} with p a prime. In this article we show that most of them admit no class regular automorphism groups. This implies that they are never obtained from generalized Hadamard matrices. As far as we know, this is the first infinite family of non class-regular symmetric transversal designs.     

Construction of additional variables conforming to a common factor model

It is shown that if a random p-vector x conforms to an r-common factor model and an external variable Z is given, then there exists a family of linear combinations X of x and Z such that [x′: X]′ conforms to an r-common factor model     

Enantioselective ester synthesis in the presence of optically active polymers

Enantiomer-differentiating ester syntheses from acid salts, chlorides, and an anhydride were studied in the presence of optically active polyamines. Enantiomer selection occurred in reactions of a racemic salt with an achiral alkyl bromide and vice versa, which is good evidence of the importance of activation of the carboxylate group by complexation of the counterion and activation of alkyl bromide by the formation of a quaternary salt with polyamine under solid–liquid, phase-transfer reaction conditions. Only small optical activity was observed in the products of acid anhydride or chloride with alcohol.     

Oscillation of the solutions of parabolic equations with nonlinear neutral terms

In the present paper the oscillatory properties of the solutions of parabolic equations with nonlinear neutral terms are investigated. Our approach is to reduce the multi-dimensional problem to a one-dimensional problem for delay differential inequalities.     

Microlocal study of topological Radon transforms and real projective duality

Various topological properties of projective duality between real projective varieties and their duals are obtained by making use of the microlocal theory of (subanalytically) constructible sheaves developed by Kashiwara [M. Kashiwara, Index theorem for constructible sheaves, Astérisque 130 (1985) 193-209] and Kashiwara-Schapira [M. Kashiwara, P. Schapira, Sheaves on Manifolds, Grundlehren Math. Wiss., vol. 292, Springer, Berlin-Heidelberg-New York, 1990]. In particular, we prove in the real setting some results similar to the ones proved by Ernström in the complex case [L. Ernström, Topological Radon transforms and the local Euler obstruction, Duke Math. J. 76 (1994) 1-21]. For this purpose, we describe the characteristic cycles of topological Radon transforms of constructible functions in terms of curvatures of strata in real projective spaces.     

Charge-order pattern of the low-temperature phase from a monoclinic single domain of NaV2O5 uniquely determined by resonant x-ray scattering

The present resonant x-ray scattering has been performed on a monoclinically split single domain of NaV(2)O(5). The observation of a critically enhanced contrast between V(4+) and V(5+) ions has led us to the unequivocal conclusion of the charge-order pattern of the low-temperature phase of NaV(2)O(5) below T(c) = 35 K. In spite of the possible four types of configuration of the zigzag-type charge-order patterns in the ab plane (A,A',B and B'), the stacking sequence along the c axis is determined as the AAA'A' type by comparison with model calculations.