A method and apparatus for optimizing information-retrieval related system performance based on users’ communication relationships. The system may also include trial or implant stem components that are inserted or implanted in the proximal and distal ends of the long bone. The dive depth of the air-charged cargo submarines is not large, so the pressure and volume of the charged air in the cargo hold are limited. In addition, a number of grooves are distributed around the boring’s circumference. The clamping mechanism includes a first clamping member which moves into the endmost group of sheets at a location outwardly of the separation between the endmost group of sheets and the next adjacent group of sheets, and further includes a second clamping member which moves toward the first clamping member to clamp a portion of the endmost group of sheets therebetween. The control piston is subjected to compressed air to move the switching valve from the stop position to the driving position.