Abstract-We consider the estimation of the position and transmit power of primary users in cognitive radio networks based on solving a sequence of 1-regularized least-square problems, in which the unknown vector is sparse and the measurements are only sequentially available. We propose an online parallel algorithm that is novel in three aspects: i) all elements of the unknown vector variable are updated in parallel; ii) the update of each element has a closed-form expression; and iii) the stepsize is designed to accelerate the convergence yet it still has a closedform expression. The convergence property is both theoretically analyzed and numerically consolidated.
For the ciphertext storage and query in the DAS (database as service) model, this paper presents a ciphertextquery algorithm based on the filtering query in database. In the data storage process, the algorithm uses a given metadata set to encode the plaintext which needs protecting, generates and stores the corresponding ciphertext index code. In the data query process, the algorithm transforms the original query statement into ciphertext based on the index code to help database server complete the ciphertext-only query task. In this paper, we implement the algorithm using Oracle system and figure out the filtration rate, the detection rate and the execution time of the algorithm. The experimental statistics show that our algorithm has good performance.
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