eliminate this overhead without transmitting additional portions.
The present invention relates to a method and system for access control in a communication network which includes a first wireless unit, a second wireless unit and at least one further unit. The first unit generates a frame for the second unit. The frame includes a first portion and a second portion. The first portion includes data indicating that the first unit is about to establish a direct communication channel with the second unit. The first portion is transmitted to the second unit and is received by the at least one further wireless unit.
A direct communication channel is established between the first unit and the second unit for transmission of the second portion. During the transmission of the second portion, the atOn the wings of dragonflies: Flapping insect uses drag to carry its weight, offering insight into intricacies of flight

Media Contact

Blaine Friedlander

ST. LOUIS -- If mastering flight is your goal, you can't do better than to emulate a dragonfly.

With four wings instead of the standard two and an unusual pitching stroke that allows the bug to hover and even shift into reverse, the slender, elegant insect is a marvel of engineering.

Z. Jane Wang, professor of theoretical and applied mechanics at Cornell University, presented her research on flying systems and fluid dynamics today (Feb. 19) at the annual meeting of the American Association for the Advancement of Science. In a seminar "Falling Paper, Dragonfly Flight and Making a Virtual Insect," she said the best way to learn about flight is