Applying FLC-based dynamic buffer size tuning to shorten the information retrieval round trip time in mobile location-aware environments

This paper proposes to use the novel fuzzy logic controller (FLC), which is a dynamic buffer size tuning technique, to support more dependable location-aware information retrieval in a pervasive environment. Within a smart space of a mobile/pervasive environment a user may request service from the dedicated surrogate via a portable small-form-factor (SFF) device (e. g. PDA). In effect, the SFF is the client and the surrogate is the server, which may serve many clients at the same time. The one-surrogate-to-many-SFF relationship or asymmetric rendezvous easily makes the surrogate buffer overflow in the peak demand seasons. The request traffic to the surrogate is tied in with the transient traveler mass traffic through the smart space, for example, in an airport. The transit travelers may switch on their mobile SFF at will to demand service from the local surrogate. If the surrogate buffer overflows, the users do not benefit from the cyber foraging provided by the pervasive computing infrastructure in the background. The FLC adaptively tunes the surrogate buffer size so that it always covers the queue length by the given D safety margin. As a result the SFF-surrogate asymmetric rendezvous becomes dependable because the chance of buffer overflow is eliminated. The dependability leads to shorter information retrieval roundtrip time ( RTT) and happier users.