# Allocating Servers in Infostations for Bounded Simultaneous Requests

Bertossi, Alan Albert and Pinotti, Maria Cristina and Rizzi, Romeo and Gupta, Phalguni (2002) Allocating Servers in Infostations for Bounded Simultaneous Requests. UNSPECIFIED. (Submitted)

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## Abstract

The Server Allocation with Bounded Simultaneous Requests problem arises in infostations, where mobile users going through the coverage area require immediate high-bit rate communications such as web surfing, file transferring, voice messaging, email and fax. Given a set of service requests, each characterized by a temporal interval and a category, an integer $k$, and an integer $h_c$ for each category $c$, the problem consists in assigning a server to each request in such a way that at most $k$ mutually simultaneous requests are assigned to the same server at the same time, out of which at most $h_c$ are of category $c$, and the minimum number of servers is used. Since this problem is computationally intractable, a $2$-approximation on-line algorithm is exhibited which asymptotically gives a $\left(2-\frac{h}{k}\right)$-approximation, where $h = min \{h_c\}$. Generalizations of the problem are considered, where each request $r$ is also characterized by a bandwidth rate $w_r$, and the sum of the bandwidth rates of the simultaneous requests assigned to the same server at the same time is bounded, and where each request is characterized also by a gender bandwidth. Such generalizations contain Bin-Packing and Multiprocessor Task Scheduling as special cases, and they admit on-line algorithms providing constant approximations.

Item Type: Departmental Technical Report Information Engineering and Computer Science Q Science > QA Mathematics > QA075 Electronic computers. Computer science Infostations, Server allocation, Bin-Packing, Greedy algorithms, Approximation algorithms, On-line algorithms, Interval coloring. DIT-02-074 12 Dec 2002

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