5.2 Infinite array of linear concatenated sectors One
infinite server spatially distributed queueing system that has provided
certain physical insights into alternative dispatching procedures is a
linear concatenated sector system. On the x-axis, assume that
sector i covers the interval from x = i/2 to
x = (i/2) + 1 for i even and from x =
-(i + 1)/2 to x = -(i - 1)/2 for i odd.
Response unit i is assigned to patrol uniformly sector i
when it is available for dispatch assignment. Each unit is assumed to be
available with probability (1 - ),
independently of the status of all other units. (It should be
clear that the independence assumption is an approximation.) The
position of each available unit is selected from a uniform distribution
over the length of the unit's sector. The random variable indicating the
position of unit i is Xi; a particular
experimental value of the random variable is xi.
Assume that an incident is reported from some point x in
sector 0 (0 x 1) and that the dispatcher must select an
available unit to assign to the incident. The incident position x
is drawn from a uniform probability density over [0, 1]. The dispatcher
may use any one of the following three selection criteria:
Let i( ) = expected travel distance for strategy i,
given a utilization factor of (i = 1, 2,
3).
Do these results make intuitive sense for limiting values of ? What practical significance do they have?
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