Abstract: Synchronizing a plurality of sensors of a wireless sensor network includes initiating, by a first sensor, a flood broadcast of a sequence discovery packet in the wireless sensor network; creating, by the first sensor in response to receiving back the sequence discovery packet, an initial broadcast sequence, wherein the initial broadcast sequence includes a list of sensor identifications, and wherein an adjacent pair of sensor identifications in the initial broadcast sequence correspond to a pair of neighbor sensors, and wherein the pair of neighbor sensors are able to communicate directly with each other; broadcasting, by the first sensor, the initial broadcast sequence, wherein the initial broadcast sequence specifies an initial order for the plurality of sensors to broadcast synchronization information to eliminate collisions in the wireless sensor network; and broadcasting, by the first sensor, a first timestamp, using a location of the first sensor in the initial broadcast sequence.

Abstract: An improved projection lens capable of substantially and advantageously implementing a distinct picture by compensating for a chromatic aberration and a residue aberration, which includes a first lens group, including a lens element convex to a screen and having a relatively weak optical power, for eliminating a spherical surface aberration; a second lens group having positive optical power and cemented with a two side lens element having a positive optical element and a lens element having a negative optical element, which have a different dispersion from each other; a third lens group having a positive optical power on an optical axis and a radius code of a curvature surface toward an upper surface of which has the same radius code as the radius curvature surface of a cathode ray tube; and a fourth lens group having a high optical power toward an upper surface of the screen for compensating for a field dependent aberration.

Abstract: An actuator of an Optical disk unit is controlled to convey an optical head to a target track in accordance with a tracking error signal and an acceleration pattern signal of the actuator. The acceleration pattern signal is integrated to obtain a commanded velocity of the actuator, and the tracking error signal is processed to determine a displacement velocity of the actuator. Also, a reference tracking error is determined in accordance with a variation of the displacement velocity. The commanded velocity, displacement velocity and reference tracking error are compared to obtain an error signal indicative of a difference between the commanded velocity and an actual displacement velocity of the actuator. The error signal is then differentiated and used to adjust the acceleration pattern signal, and the thus corrected acceleration pattern signal is used to drive the actuator.

Abstract: A tracking induction system and method in which an artificial tracking induction signal is generated by selectively outputting one of a tracking error signal that is a well-known position error signal detected by a detector of an optical disc driver, a sum signal that is a signal phase-shifted 90.degree. from the position error signal and provided by the detector, a tracking error enable signal, a -V on signal and a +V on signal, the latter three signals being provided by a microprocessor, according to a selective switching operation of a switching unit for each track interval, so that the artificial tracking induction signal is applied to a tracking servo circuit, thereby achieving a tracking induction to a target track, even at intervals of .+-.1/2 track pitches or more from the target track.