X-axis and the Y-axis. It is shown that there exists a competitive algorithm for this restricted version, namely there is an online algorithm for this "axis-bound CNN" with competitive ratio 9.0." />


The Axis-bound CNN Problem

Kouki YONEZAWA  Kazuo IWAMA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E87-A   No.5   pp.1235-1242
Publication Date: 2004/05/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Algorithms and Data Structures
Keyword: 
online algorithms,  CNN problem,  

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Summary: 
In the CNN problem, a "scene" appears on the two-dimensional plane, at different positions sequentially, and a "camera crew" has to shoot the scene whenever it appears. If a scene appears at some position, the camera crew does not have to move to the position exactly, but has only to move to a point that lies in the same horizontal or vertical line with the scene. Namely it is enough to move either to the same row or to the same column. The goal is to minimize the total moving distance of the camera crew. This problem has been quite popular in the last decade but it is still open whether or not there is a competitive algorithm, i.e., an algorithm with competitive ratio bounded by a constant. In this paper we study this problem under a natural restriction that the server can move only along the X-axis and the Y-axis. It is shown that there exists a competitive algorithm for this restricted version, namely there is an online algorithm for this "axis-bound CNN" with competitive ratio 9.0.