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In order to improve the storage efficiency of Hadoop Distributed File System (HDFS) and its load balancing ability, this paper presented a distributed storage method based on information dispersal algorithm (IDA). The method used IDA to encode files to blocks, and stored the blocks in the cluster by the improved data placement strategy. The results and analysis of the experiments show that the method improves the storage efficiency and load balancing ability.

Analyzed some shortages of the existing one-time password (OTP) authentication schemes, a new OTP authentication scheme is designed. This scheme used the SM2 cryptographic algorithm and Hash function to ensure data transmission security, provided the mutual authentication between client and server, resisted different kinds of attacks, and protected the user's identity information effectively. Analysis showed that compared with the existing schemes, the new designed scheme had higher security, small system overhead and easy to implement.

A first stage of a SHA-less 12-bit 200 MSps pipeline analog-to-digital converter (ADC) is designed in this paper. A high speed and high precision comparator is designed in order to reduce the transmission delay of the comparator. RC network of the multiplying digital-to-analog converter (MDAC) and Sub-ADC should be strict matched in order to reduce the sampling errors between the two path. The prototype circuit, implemented in SMIC 130nm 1P5M CMOS process under 1.2V power supply with a 94MHz input signal and 200MHz sampling clock, demonstrates a SNDR of 82.7dB, a SNR of 72.6dB, and a ENOB of 11.83 bit.

An experiment of vortex flowmeter in oil-gas-water vertical upward three phase flow has been reported in this paper. In this research, the diameter of the pipeline is 50mm. The flow of the water varies from 5m3 /h to 8 m3 /h. For the total mixed flow, oil is occupying from 5% to 30%, and the gas proportion of the void fraction is from 1% to 5%. The results show that the measurement error of oil-gas-water three-phase is relatively small and has direct reference value for measuring the oil-gas-water three phase flow. The experiment showed that the volume measured by the vortex flow-meter was less influenced by media with low gas content.