Abstract: A method for optimizing a Polar-RNNA quantizer of MLC NAND flash based on deep learning comprises the following steps: Step S1: transforming an MLC flash detection task into a deep learning task, and obtaining three hard-decision read thresholds based on a neural network; Step S2: expanding six soft-decision read thresholds based on the three hard-decision read thresholds; Step S3: constructing an LLR mapping table, and obtaining new LLR information of MLC flash based on the LLR mapping table; Step S4: symmetrizing an MLC flash channel, and performing density evolution; and Step S5: optimizing the soft-decision read thresholds based on a genetic algorithm to obtain an optimal quantization interval. According to the invention, polar codes can be directly used for MLC flash channels without the arduous work of MLC flash channel modeling, so that the reliability of MLC flash is effectively improved.

Abstract: A transient electromagnetic device with variable shape and turns includes squares, a transmitting coil carrying frame, a transmitting coil, a turns-variable device, a current generator and a working power supply. The transmitting coil carrying frame is arranged inside the transmitting coil; the transmitting coil carrying frame is configured as a carrier of the transmitting coil, and configured for adjusting a side length of the transmitting coil and a shape of the transmitting coil; the square is configured for clamping and connecting the transmitting coil and the transmitting coil carrying frame to fix the transmitting coil to the transmitting coil carrying frame. The current generator is configured for generating transient current; the turns-variable device is configured for changing the turns of the transmitting coil; and the transmitting coil is configured for transmitting the transient current to a target area to be measured.

Abstract: The present invention discloses a method for query of domain names of telephone numbers, e.g., E.164 numbers. The method comprises: in ENUM DNS (Electronic numbers to URI Mapping Domain Name System), dividing a domain name of a telephone number into a public domain name part and a digit domain name part; storing sequentially public domain name information separated by spacer(s) in the public domain name part and the data obtained by arranging digits in the digit domain name part in a preset order into nodes of a search tree according to storage rules of the search tree; on receiving a query request, the ENUM DNS obtaining the public domain name information of the domain name and finding the corresponding nodes according to search tree rules; obtaining the digits separated by spacer(s) in the domain name, arranging the digits into data in a prescribed order of the system, and finding the next-level nodes of the search tree.