{ "id": "1004.1850", "version": "v8", "published": "2010-04-11T22:27:34.000Z", "updated": "2011-06-28T08:32:42.000Z", "title": "Level-crossings of symmetric random walks and their application", "authors": [ "Vyacheslav M. Abramov" ], "comment": "Substantially revised, will be submitted", "categories": [ "math.PR" ], "abstract": "Let $X_1$, $X_2$, $...$ be a sequence of independently and identically distributed random variables with $\\mathsf{E}X_1=0$, and let $S_0=0$ and $S_t=S_{t-1}+X_t$, $t=1,2,...$, be a random walk. Denote $\\tau={cases}\\inf\\{t>1: S_t\\leq0\\}, &\\text{if} \\ X_1>0, 1, &\\text{otherwise}. {cases}$ Let $\\alpha$ denote a positive number, and let $L_\\alpha$ denote the number of level-crossings from the below (or above) across the level $\\alpha$ during the interval $[0, \\tau]$. Under quite general assumption, an inequality for the expected number of level-crossings is established. Under some special assumptions, it is proved that there exists an infinitely increasing sequence $\\alpha_n$ such that the equality $\\mathsf{E}L_{\\alpha_n}=c\\mathsf{P}\\{X_1>0\\}$ is satisfied, where $c$ is a specified constant that does not depend on $n$. The result is illustrated for a number of special random walks. We also give non-trivial examples from queuing theory where the results of this theory are applied.", "revisions": [ { "version": "v8", "updated": "2011-06-28T08:32:42.000Z" } ], "analyses": { "subjects": [ "60G50", "60K25" ], "keywords": [ "symmetric random walks", "level-crossings", "application", "quite general assumption", "special random walks" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1004.1850A" } } }