This paper presents the profit analysis of a system of two non-identical units in which one unit is original which is initially operative and the other is duplicate kept in cold standby. The units may fail completely directly from normal mode. There is a single server who visits the system immediately when required. The original unit undergoes for repair upon failure while only replacement of t...

Research teams are the fundamental social unit of science, and yet there is currently no model that describes their basic property: size. In most fields, teams have grown significantly in recent decades. We show that this is partly due to the change in the character of team size distribution. We explain these changes with a comprehensive yet straightforward model of how teams of different sizes...

The standard approach of counting the number of eigenmodes of N scalar fields near the horizon is used as a basis to provide a simple statistical mechanical derivation of the black hole entropy in two and four dimensions. The Bekenstein formula S = A 4Gh̄ and the two-dimensional entropy S = 2M/λh̄ are naturally obtained (up to a numerical constant of order 1). This approach provides an explanatio...

Abstract: The present paper concludes via an analytical method to reduced formulae for determining the eigenfrequencies and eigenmodes of multi-span continuous beams with spans of different lengths and bending rigidities in a very easy and efficient way. The rigorous determination of eigenfrequencies and eigenmodes allows us to focus on the derivation of the time function for the forced vibrati...

Eigenmode solutions are very important in stability analysis of dynamical systems. The set of eigenvalues of a non-self-adjoint differential operator originated from the linearization of some Cauchy problem is investigated. It is shown that the eigenvalues are purely imaginary, and that they are related to the eigenvalues of Heun’s differential equation. These two results are used to derive the...

The existence of quasi-periodic eigensolutions of a linear second order ordinary differential equation with quasi-periodic coefficient f{a>it, io%t) is investigated numerically and graphically. For sufficiently incommensurate frequencies coi, a>2 a doubly indexed infinite sequence of eigenvalues and eigenmodes is obtained. The equation considered is a model for the magneto-hydrodvnamic "continu...

Abstract. Simulating numerically the sound radiation of a rolling tire requires the solution of a very large and sparse gyroscopic eigenvalue problem. Taking advantage of the automated multi– level substructuring (AMLS) method it can be projected to a much smaller gyroscopic problem, the solution of which however is still quite costly since the eigenmodes are non–real and complex arithmetic is ...