We develop a model for broadcasting data to wireless appliances. Any data item may either be “pushed”, or broadcast without waiting for requests for the item, or it may be “pulled”, or broadcast in response to a request. Pushing items is cheaper than handling the individual requests, but if pushed items are not wanted, the bandwidth for broadcasting them is wasted. We determine the optimal allo...

Short Abstract: Traveling waves describe diverse natural phenomena from crystal growth in physics to range expansions in biology. Two classes of waves exist with very different properties: pulled and pushed. Pulled waves are noisy because they are driven by high growth rates at the expansion edge, where the number of organisms is small. In contrast, fluctuations are suppressed in pushed waves b...

GLOSSARY OF SYMBOLS r distance from pressure sample point to center of piston a radius of circular radiator R_ dc resistance of driver voice coil ao radius of diaphragm, = _/SD/_r E surface area ay radius of circular vent, = 5/Sv/_r SD effective projected surface area of driver diaphragm c velocity of sound in air, = 343 m/s Sv cross-sectional area of vent ein voltage applied to driver input SP...

Monitoring the condition of electrolytic capacitors in practical applications is a topic that has been and remains subject much research. This article part research this area. It develops parameter observer (PO) proposes its use for determination equivalent capacity serial resistance capacitors. The an integral-open-loop type second-order system, input which voltage at capacitor terminals measu...

instrument breakage during treatment can lead to serious complications and carries the risk of treatment failure. when a file breaks in the canal, bypassing or removal can be difficult and the long-term prognosis of the tooth may be compromised. sometimes surgery may be indicated for removal of the broken segment. often some part of the root cannot be cleaned because of blockage by the broken f...

The Industrial Revolution in England was characterised by early and rapid labour release from agriculture to industry. This was facilitated by rising levels of labour productivity in agriculture which permitted labour to be released without excessive upward pressure on food prices. New technology played a central role in raising agricultural productivity but the importance of particular innovat...