An LED light string including a first loop, which further includes a first plurality of LEDs in series successively connected by first connecting wires, and at least one first resistor connected to two first resistor wires, the first two resistor wires removably connected to two of the first connecting wires in any portion of the first loop. An image pickup apparatus includes a zoom lens barrel that moves between a retracted position and a shooting position in an optical axis direction to thereby change a photographing magnification. The extracting of the control parameter comprises utilizing an analytic coordinate system that quantitatively relates the electrical characteristic of the matching system to the electrical characteristic of the power transmission line. The adjusted image of the microarray is compared with a database of stored microarray pixel data to extract information from said image. When an event occurs in a module, the module issues an event notification that is then handled by a handling process. Each protruding structure includes two conical frustums aligned at a center axis and stacked together.