Continuity theorems for the M/M/1/nM/M/1/n queueing system

In this paper continuity theorems are established for the number of losses during a busy period of the $M/M/1/n$ queue. We consider an $M/GI/1/n$ queueing system where the service time probability distribution, slightly different in a certain sense from the exponential distribution, is approximated by that exponential distribution. Continuity theorems are obtained in the form of one or two-sided stochastic inequalities. The paper shows how the bounds of these inequalities are changed if further assumptions, associated with specific properties of the service time distribution (precisely described in the paper), are made. Specifically, some parametric families of service time distributions are discussed, and the paper establishes uniform estimates (given for all possible values of the parameter) and local estimates (where the parameter is fixed and takes only the given value). The analysis of the paper is based on the level crossing approach and some characterization properties of the exponential distribution.Comment: Final revision; will be published as i

Особенности расчета освещенности, эквивалентной шуму, для тепловизионных и телевизионных систем

Запропоновано узагальнена методика розрахунку освітленості, що еквівалентна шуму, для тепловізійних і телевізійних систем, яка враховує спектральні характеристики випромінювання об’єкта й фону, пропускання атмосфери та об’єктива, чутливості приймача випромінювання.A generalized technique is proposed for calculating the noise-equivalent irradiance for thermovision and television systems. It takes into account spectral characteristics of a target, background radiation, atmospheric and a objective lens’ transmittance, as well as a detector’s sensitivity.Предложена обобщенная методика расчета освещенности, эквивалентной шуму, для тепловизионных и телевизионных систем, которая учитывает спектральные характеристики излучения объекта и фона, пропускание атмосферы и объектива, чувствительности приемника излучения

Influence of processing conditions on the structure and properties of yttrium oxide ceramics

By means of "wet" chemistry method Y₂O₃ nanopowder was obtained and characterized by X-ray diffraction analysis and differential thermal analysis. Transparent samples of Y₂O₃ and Y₂O₃:Nd ceramics were produced by vacuum sintering. Granulometric and phase compositions, crystal structure, spectral-kinetic and mechanical properties of the ceramics were studied