232 research outputs found
Resource-Adaptive Newton's Method for Distributed Learning
Distributed stochastic optimization methods based on Newton's method offer
significant advantages over first-order methods by leveraging curvature
information for improved performance. However, the practical applicability of
Newton's method is hindered in large-scale and heterogeneous learning
environments due to challenges such as high computation and communication costs
associated with the Hessian matrix, sub-model diversity, staleness in training,
and data heterogeneity. To address these challenges, this paper introduces a
novel and efficient algorithm called RANL, which overcomes the limitations of
Newton's method by employing a simple Hessian initialization and adaptive
assignments of training regions. The algorithm demonstrates impressive
convergence properties, which are rigorously analyzed under standard
assumptions in stochastic optimization. The theoretical analysis establishes
that RANL achieves a linear convergence rate while effectively adapting to
available resources and maintaining high efficiency. Unlike traditional
first-order methods, RANL exhibits remarkable independence from the condition
number of the problem and eliminates the need for complex parameter tuning.
These advantages make RANL a promising approach for distributed stochastic
optimization in practical scenarios
The Role of AM Symbiosis in Plant Adaptation to Drought Stress
Symposium paper Part 1: Function and management of soil microorganisms in agro-ecosystems with special reference to arbuscular mycorrhizal fung
Surface charging on HVDC spacers considering time-varying effect of temperature and electric fields
The dynamic behavior of surface charging on spacers in DC-GILs can be influenced by multi-factors including the non-uniform distributed electric field as well as the time-varying temperature gradient. In this paper, the time-varying effect of surface charging phenomenon on spacers is studied and a time-varying mathematical model is established, based on the influence of temperature and electric field on the ion mobility at the gas phase and the bulk conductivity in the solid phase. The results verify that the bulk conductivity can be greatly influenced by temperature, which leads to an increase in the surface charge density on the spacer. This allows the surface charge accumulation to stabilize more quickly. However, the ion mobility from the gas phase is less affected by temperature. When the non-uniform distributed electric field changes from 1.3 to 6.4 kV/mm, ion mobility is less influenced and the surface charge density on the spacer varies slightly. In this case, the effects of the non-uniformly distributed electric field in surface charge density variation is much smaller and can be ignored
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