19,385 research outputs found
A stochastic two-step inertial Bregman proximal alternating linearized minimization algorithm for nonconvex and nonsmooth problems
In this paper, for solving a broad class of large-scale nonconvex and
nonsmooth optimization problems, we propose a stochastic two step inertial
Bregman proximal alternating linearized minimization (STiBPALM) algorithm with
variance-reduced stochastic gradient estimators. And we show that SAGA and
SARAH are variance-reduced gradient estimators. Under expectation conditions
with the Kurdyka-Lojasiewicz property and some suitable conditions on the
parameters, we obtain that the sequence generated by the proposed algorithm
converges to a critical point. And the general convergence rate is also
provided. Numerical experiments on sparse nonnegative matrix factorization and
blind image-deblurring are presented to demonstrate the performance of the
proposed algorithm.Comment: arXiv admin note: text overlap with arXiv:2002.12266 by other author
Research on a safety evaluation system for railway-tunnel structures by fuzzy comprehensive evaluation theory
Long-term health detection of railway-tunnel is the development direction and trend of future railway tunnel research. Based on the actual engineering of a railway tunnel, this study developed a safety evaluation model for railway tunnel structures using a fuzzy comprehensive evaluation method and examined a health state evaluation method suitable for most railway tunnel structures. The results showed that the evaluation method comprehensively reflected the impact of various factors, which had strong practicality. The evaluation results were clear, accurate, and consistent with engineering practice. When using the safety factor index to study the stress of a railway tunnel structure, Midas/civil analysis showed that different levels of the surrounding rock structural vault in railway tunnels were in a tensile, control-bearing capacity state. When calculating safety factors, the range of a 60° central angle of a railway tunnel vault was calculated according to the tensile control-bearing capacity. Theoretical formulas of the range of the center angle φ0 of the vault tension zone were derived and then verified by experiments and numerical analysis
Fine-Grained Access Control Systems Suitable for Resource-Constrained Users in Cloud Computing
For the sake of practicability of cloud computing, fine-grained data access is frequently required in the sense that users with different attributes should be granted different levels of access privileges. However, most of existing access control solutions are not suitable for resource-constrained users because of large computation costs, which linearly increase with the complexity of access policies. In this paper, we present an access control system based on ciphertext-policy attribute-based encryption. The proposed access control system enjoys constant computation cost and is proven secure in the random oracle model under the decision Bilinear Diffie-Hellman Exponent assumption. Our access control system supports AND-gate access policies with multiple values and wildcards, and it can efficiently support direct user revocation. Performance comparisons indicate that the proposed solution is suitable for resource-constrained environment
STEADY-STATE ANALYSIS OF THE GI/M/1 QUEUE WITH MULTIPLE VACATIONS AND SET-UP TIME
In this paper, we consider a GI/M/1 queueing model with multiple vacations and set-up time. We derive the distribution and the generating function and the stochastic decomposition of the steady-state queue length, meanwhile, we get the waiting time distributions. Key words: multiple vacations, set-up time, stochastic decompositio
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