Abstract: An automatic security enhancement system can automatically increase the security of the system when necessary. The system has at least two different states with each state has different security level. The state with low security could be changed into a state with higher security automatically when the system detects someone try to break the system. The state with low security could also be instructed to change into a state with higher security. However, a state with higher security will be changed into a state with lower security only when the system is commanded to do so.

Abstract: An automatic gain control circuit with a very wide operational range, less hardware, and faster response, and more flexibility includes a signal strength estimator, a gain adjusting factor device and a multiplier. After the signal strength estimator finds signal strength, the gain adjusting factor device will generate a gain adjusting factor corresponding to the signal strength. Then the multiplier will update gain by multiplying it the gain adjusting factor.

Abstract: A method and system are provided for a general computing software system to extract, reconstruct, save, and retrieve the information presented by an information source by assigning explicitly or implicitly properties to formulas, figures, and their components and making mathematics formulas as the bridges between the mathematics formulas in a document and the mathematics formulas and library functions in databases.